A sizeable protective measure that’s present on Earth is the atmosphere. The atmosphere and magnetic field protect humans from large amounts of radiation from space. The ozone layers of our atmosphere prevent excess ultraviolet (UV) radiation from reaching us by absorbing harmful UV particles, especially UVB. However, when these protective measures are unavailable in space, the radiation exposure, especially UVB, drastically increases. (Make sure to pack SPF 1000+ before your next trip to space). In space, the vacuum results in a lack of an atmosphere and ozone layers, our protectors. Radiation from the sun and cosmic rays interfere with the body’s natural processes and can cause cancer, degenerative diseases, and radiation sickness. There are various methods by which this can happen, many of which are due to heavy ion exposure. For example, exposure to carbon ions contributes to the breakage of chromosomes during mitosis, or when exposed to high-energy iron and silicon ions, the growth pathways associated with bronchial epithelial cells (cells that line the airway paths in the lungs) are upregulated, potentially leading to lung cancer. Additionally, exposure to certain heavy ions can decrease programmed cell death and increase rapid cell growth, leading to the start of tumors.
The sudden increase in exposure to radiation that occurs in space is coupled with a sudden decrease in gravity acting on the body. A lack of gravity can interfere with many bodily processes since we are accustomed to a force pulling us down. One such process is the daily destruction and reconstruction of bones. Without gravity, bones have very little weight to support, so the natural process of degeneration and regeneration is disrupted. Bones naturally break down and rebuild over time. However, when there’s no gravity, there’s less weight on the bones, leading to less regeneration since the bones don’t need to be as dense to support a heavy weight. Overtime this causes a degradation of the bone mass, known as disuse osteoporosis. The calcium from the bones gets into the bloodstream and, combined with dehydration, can lead to kidney stones. Muscles are also broken down since they are not used as much. With no gravity to act against, the muscles aren’t under constant stress like they are on Earth, so they break down.
Zero gravity can also alter sensory and motor skills. Fluids on Earth are pulled down because of gravity. However, in space, they have no specific direction to flow in, so they kind of just float around. The same happens with bodily fluids (thank god astronauts don’t just pee into space). Some bodily fluids help maintain a sense of awareness of the orientation and location of the body, which is known as proprioception. Shifts from the normal patterns of flow of these fluids may cause eye problems and lead to sensory reweighting. The vestibular senses, which occur in the ear, determine the head’s orientation and help keep the body upright. This relies on inner ear fluid. The motion of the fluid alerts the brain as to how the head is positioned and can trigger motor responses based on this information. This is why you may sometimes feel like you are falling while lying down: your inner ear fluid will move similarly to when you are falling. Since the fluid flow is unreliable in space, the brain tends to rely more on the vision and proprioception senses to gather information on its surroundings and the body’s orientation. Like the circulatory system, these senses take a while to readjust once back on Earth. Astronauts face post-flight orthostatic intolerance, where they cannot maintain blood pressure while standing up. The body is not yet accustomed to pumping blood against gravity.
Although space travel seems fascinating, the effects of being away from home significantly affect the body. Radiation and zero gravity put the body through physical stressors and may lead to diseases like osteoporosis or cancer. It can also change the way certain bodily functions occur. However, the reward of space travel far outweighs the challenges, and hopefully one day all the kids obsessed with space will have a lot more to learn about.
https://www.nasa.gov/hrp/bodyinspace
https://www.nasa.gov/missions/station/bone-and-muscle-loss-in-microgravity/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8577506/
https://unsplash.com/photos/astronaut-in-white-suit-in-grayscale-photography-I0fDR8xtApA
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How does music trigger the brain’s reward system?
“It’s like I got this music in my mind saying it’s gonna be alright”
As it turns out, listening to music triggers the reward system in the human brain. This means that when we encounter something rewarding, like music, a region in the midbrain called the Ventral Tegmental Area is stimulated to produce dopamine. Dopamine is a neurotransmitter that plays a role in mood, learning, attention, and–most relevant here–reinforcement. The so-called “dopamine rush” we get from something that brings us joy keeps us coming back for more. Once dopamine is released, it travels through the mesolimbic pathway to the Nucleus Accumbens (NAc) located in the forebrain. When it binds to receptors there, we feel pleasure. In fact, it’s this process that’s responsible for the sensation of “chills” while listening to music, but we’ll get to that later! Once we associate pleasure with a certain stimulus, we seek out that stimulus again and again (Guy-Evans). This is the same neurological response associated with behaviors like eating and sex—behaviors required for an organism to survive and reproduce. Listening to music, however, is not quite on that level. All organisms must exhibit evolutionarily necessitated behaviors, but I don’t see chimpanzees screaming “You Belong With Me” at the top of their lungs.
So, what makes humans different? As organisms get more complex and more capable of higher-order thinking, the activities that can trigger the brain’s reward system get more complex as well. Specifically, it’s higher-order processing by the cerebral cortex (the region responsible for language, thought, emotion, and personality) that determines what humans find rewarding. Humans can connect stimuli that don’t directly relate to survival with survival in a way that other animals cannot. Music fosters human connection (“Taylor, you’ll be fine!”), and, therefore, survival. Listening to music triggers the same dopamine response as these other biologically rewarding stimuli, which connects them. Thus, something like music, which is integral to human communities and social behavior but not necessarily a requirement for survival, can still elicit the same response as something that is required for survival.
Dopamine is released as a response to a stimulus, leading to pleasure. Specifically, certain cells are responsible for releasing dopamine in conjunction with pattern prediction. Music is, of course, built upon patterns. For example, the click of a metronome can be organized into patterns, such as the two-beat feel of a march or the three-beat feel of a waltz. Similarly, the repetition of a certain melody, perhaps the chorus of a song (“You got that James Dean daydream look in your eyes”), adds a periodicity to what is perceived and keeps the brain anticipating the next repetition. It’s this cycle of anticipation and reward that is so addictive, as it takes advantage of both our brain’s affinity for patterns and the reinforcement cycle created by dopamine release.
How does this contribute to emotional response?
“And I never knew I could feel that much”
All of this is happening in the brain when we listen to music, leading to the emotions we feel. One aspect of our emotional response to music is the way we identify with it. There’s a system in the brain called the Default Mode Network (DMN) that is active when the brain is not actively paying attention to something. It’s associated with introspection, self-awareness, and understanding others and is active during times of “mind-wandering.” As one study found, it’s also active while listening to music one enjoys. Listening to music in general corresponds with increased activity in the DMN, but the most increased activity was measured while study participants listened to music they enjoyed. Increased DMN activity means music is tied to the states and behaviors associated with the DMN, as outlined above.
In a different study, emotional arousal was measured in conjunction with participants’ reported pleasurable experiences listening to music. Activity in the Sympathetic Nervous System (activated for a “fight or flight response”) was used to measure emotional arousal. Sure enough, increased Sympathetic Nervous System activity correlated with increased participant pleasure ratings. Furthermore, when one experiences a “peak experience” (more on that later) while listening to music, there is a higher dopamine response in the mesolimbic striatum, the same pathway associated with the reward discussed above! This is further supported by the fact that when comparing music that does provoke a pleasurable response (for me, Folklore), to music that does not, there is greater NAc activity, a.k.a. greater reward value! These studies illustrate that subjective ratings of pleasure correlate with the neurobiological process of dopamine release in the brain.
Oddly enough, “pleasurable” doesn’t necessarily mean happy. Listening to sad music can lead to the same pleasure response as happy music. For example, it’s possible to get chills (pleasurable) while listening to sad music. One potential explanation for this bizarre paradox is the so-called “consoling” reaction, the comforting response certain hormones cause when you cry. This response is the reason you might feel better after crying (or listening to All Too Well (10 Minute Version) (Taylor’s Version)). Another paradox presented by the brain’s response to music is that music can be both energizing and calming (think: your workout playlist vs. a lullaby, or 22 vs. peace). This is because music is capable of manipulating arousal. In a study conducted on mothers, arousal levels were lower while singing calming songs to their babies. While singing playful songs, arousal levels were higher. This is potentially due to music’s impact on the amygdala, a brain structure closely associated with emotion.
Music has the ability to impact many different neurobiological processes, leading to the wide variety of emotional states it can provoke.
Why do we get chills while listening to music?
“But can you feel this magic in the air?”
And, when music impacts us emotionally, we may get chills/thrills/goosebumps (survey’s out on the most popular word). Chills are a manifestation of what is known as a “peak experience”, as mentioned above. They correlate with the peak emotional response to a piece of music. Chills are also associated with different observable traits of Sympathetic Nervous System arousal, like an increased heart rate. Thus, chills are often used by scientists in this field as a marker of emotional arousal. Chills can result from both positive and negative experiences (like chills from fear). For simplicity’s sake, pleasurable chills are referred to as “frisson”, a French word for the pleasurable variation of this sensation. Various studies have determined that at least half of the population experiences frisson from music, with some studies putting the number closer to three-fourths. This number is higher in musicians, perhaps because those who experience chills are more likely to pursue music.
Chills, like the pleasure responses outlined above, are also connected with Sympathetic Nervous System arousal. In people who experience frisson, the parts of the brain responsible for auditory processing and those responsible for emotion are more connected. Frisson correlates with increased blood flow in the NAc, the same structure associated with dopamine release. So, the dopamine rush we get while listening to pleasurable music leads to a physiological reaction. In addition to NAc activity, the moments preceding frisson are accompanied by activity in the caudate, another structure involved with reward. In fact, the blood flow patterns in the brain during musical frisson show a striking similarity to those of addiction. The same sort of “craving” takes place. In musicians and extreme Swifties (holders of the over 4.35 million Eras Tour tickets sold), that craving is intense.
There are many theories for why this happens. One theory suggests that the human ear is attuned to the sound of an infant crying, leading to a physiological response, like chills. Having a response like this means that humans are more likely to connect with a crying infant, which, naturally, is of evolutionary importance. This phenomenon is then extended to other auditory stimuli, like music. Another theory suggests that frisson results from the contrast generated by a positive response when preceded by a negative one. For example, when riding a rollercoaster, initial sensations of fear are soon overrun by joy as you realize your life isn’t actually in danger. This, too, could lead to frisson. According to this model, unexpected sounds, as presented by music, trigger a fear response that is quickly replaced by pleasure once the stimulus is recognized as music. The contrast here makes the positive response more potent, leading to frisson. Goosebumps, or piloerections, are also commonly a fear response, suggesting that this fear response is connected to frisson. According to this theory, it’s the combination of high fear and high pleasure that causes the sensation.
Conclusion
“I can see the end, as it begins”
So, next time you find yourself scream-singing along to 1989 (Taylor’s Version), know that you have your brain to thank! And, when you find yourself tapping through your Spotify Wrapped, wondering how on Earth you listened to the same song that many times, know that our brain’s reward system is hard at work, making you come back time and time again.
https://www.jstor.org/stable/42706677
https://www.simplypsychology.org/brain-reward-system.html
https://www.health.harvard.edu/mind-and-mood/dopamine-the-pathway-to-pleasure
https://www.jstor.org/stable/40351765?seq=4
https://www.jstor.org/stable/24755599
https://www.ncbi.nlm.nih.gov/books/NBK92781/
https://daily.jstor.org/why-do-we-listen-to-sad-music/
https://www.sciencedirect.com/science/article/pii/S157106451730163X
https://www.nature.com/articles/nn.2726
https://www.bbc.com/culture/article/20221124-why-music-can-give-you-chills-or-goosebumps
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0007487
https://www.researchgate.net/publication/285500789_Musical_Expectancy_and_Thrills
https://neurosciencenews.com/music-chills-neuroscience-6167/
https://www.frontiersin.org/articles/10.3389/fpsyg.2014.00790/full
https://open.spotify.com/track/3pv7Q5v2dpdefwdWIvE7yH?si=4xTl3OZeRGSMWG4eM0PAZw
https://open.spotify.com/track/22bPsP2jCgbLUvh82U0Z3M?si=2KzL5kV5TIe8HEczs264UA
https://open.spotify.com/track/1K39ty6o1sHwwlZwO6a7wK?si=c1BiTqwIQlueVzYlDdUftg
https://open.spotify.com/track/3Vpk1hfMAQme8VJ0SNRSkd?si=bc0bf4efe3e149e1
https://unsplash.com/photos/taylor-swift-album-RjD01Is-KnI
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Seed Germination
It all starts with embryogenesis, a developmental process in which the plant maps out its “body plan” through cell differentiation, or the process of creating new cells and various hormonal signals. By this time, the plant has turned from a single cell into a multicellular organism with built-in food reserves and a protective layer. This is also known as the seed. But the plant’s stuck in its own shell. How does it come out?
The plant breaks free from its cage through a process called germination. Like all good things, it only occurs when conditions are right: there has to be water uptake by the seed and the right ratio of ABA to GA hormones. ABA (Abscisic acid) and GA (Gibberellins) are both phytohormones, or plant hormones. ABA inhibits seed germination, and in general if a plant is producing more ABA, that means the plant is undergoing some type of stress due to environmental conditions. The most common is water stress (ie. drought conditions), in which a plant produces more ABA, telling its parts to slow down growth to conserve water and other nutrients. On the other hand, GA is a family of molecules that promote seed germination and stem growth in a plant. A low ratio is needed for the germination of a seed. There’s not a set value to reach as it changes for each plant species – in general the lower the ratio, the better the chance it has at germinating. That’s why it’s not uncommon to see plants that develop fruit only after a cold winter, such as the carrots you might see growing in UC San Diego campus’ community gardens. On the other hand, there are plants with seeds that only germinate after a fire, such as the Eucalyptus trees seen around UC San Diego.
The emergence of the radicle, or embryonic root, is one of the first visible successes of a growing plant. Closely following comes the stem and then the cotyledons, which are the first leaves of the plant. During this time the embryo undergoes polarized growth, which is another way to say the embryo establishes a sense of directionality and starts dividing its cells based on that directionality. The plant establishes two axes: the apical-basal axis( up-and-down), and the radial axis( in-and-out). Another family of phytohormones called auxins play a key role in developing this directionality. Auxins are tiny but mighty; they’re smaller than most other phytohormones, but are present in almost every stage of a plant’s life. They’re responsible for cell growth, and do this through sensing the plant’s environmental conditions. For example, light and gravity are important factors auxins react to in order for the plant to grow. That’s why you see plants, for example the pumpkin, will grow ‘towards’ the sun. This is from auxins in the plant concentrating towards the side where there is no sun, forcing cells on the other side to elongate towards the sun!
Cell Formation
So far, the plant has gotten a better sense of its bearings, but how does it actually create its leaves, flowers, spines, branches, and fruit? It differs between different types of plants, so let’s focus on the phylum ‘Angiosperm’, which includes the most recently evolved plants in the plant kingdom. Angiosperms encompass all plants that flower and bear fruit such as the pumpkin plant cared for by Mr. Geinger.
These plants organize themselves into their respective shoot and root systems. Each system is composed of different organs made of different tissues, similar to a human body’s organization. One kind of tissue, called meristematic tissue, is the source of all cell formation and growth in the plant. Think of it as a fountain of youth for the plant. There’s the SAM (shoot apical meristem) that form parts of the plant like leaves, stems, and flowers. Areas in which higher levels of SAM meristem cells are found are ‘peripheral zones’. This is where the leaves and flowers (which are bunches of highly modified leaves) are created. You can think of it as the plant’s ‘torso’. It has ‘arms’ that help it absorb sunlight and grow taller as it receives more nutrients. But these meristem cells aren’t the only players in this reaction. For instance, in flower formation, environmental conditions and a whole range of proteins called ‘transcription factors’ that help copy DNA, play big roles in whether or not a plant is able to flower at all.
Then there’s the RAM (root apical meristem) that facilitates root growth. From the radicle, the root grows downward with the help of gravity to form new cells coming from the RAM. Think of these as the plant’s ‘legs’. Although it can’t physically move, the roots aid the plant in finding nutrients, like how those late night food runs always hit the spot. There’s even a root cap covering the tip of the root to protect its RAM while traversing the underground terrain, similar to how a shoe is used to protect your feet.
Knowing all of this now, it’s clear to see there’s so much more going on in Travis Geinger’s pumpkin than just a pollinated flower turning into a fruit. The whole plant fights everyday to stay alive with help from its molecular mechanisms and systems, along with some luck from genetics. The growth of a pumpkin wasn’t just pure luck though; environmental conditions had to be favorable, the plant needed all its nutrients, and lots of tender loving care!
Links Used:
Squash goals: Minnesota man’s 2,749lb pumpkin sets world record | California | The Guardian
https://open.lib.umn.edu/horticulture/chapter/4-2-plant-hormones/
2.2: Introduction to Seed Germination – Biology LibreTexts
30.11: Plant Development – Meristems – Biology LibreTexts
Molecular mechanisms of flower development: an armchair guide | Nature Reviews Genetics
]]>But what exactly is “clean eating”? Clean eating focuses on foods that are as close to their natural state as possible, free from harmful chemicals and probably organic. A survey conducted by the Food Information Council showed that for “clean eaters”, they tend to consume foods that are not highly processed, sticking more to fresh fruits and vegetables as well as foods that have a short ingredient list with as little complicated names and terms as possible.
Clean eating in moderation has wonderful benefits for our body. Personally, I have noticed a dramatic improvement in my skin health and overall mood when I cut down on refined sugars and junk food. The days when I eat more sugar (read chocolate, chips and fried, greasy foods), my skin tends to have bigger, redder pimples over the next few days and seems to look more dull and thin. My mother and grandmother, since I was a kid, have stressed the importance of having a healthy, moderate diet. Especially growing up in India, my diet consisted of home-cooked foods made of organic fruits, vegetables and grains. Since coming to the US, I have noticed the incredible amount of delicious sugary snacks that are constantly available in every corner of the street, and how easy it is to indulge in them. With this uptake in sugar in my diet, I have noticed my skin gets more breakouts easily and more hyperpigmentation. (Hyperpigmentation is when our body overproduces melanin in a certain part of our body, causing it to appear darker. For example, after you have a pimple, the area where it was could appear darker due to this accumulation of melanin. )
When we cut out sugary foods, there is a decrease in inflammation (read: those pesky pimples and acne you’re trying to get rid of!). This is because high sugar foods cause an increase in insulin in our bodies, an enzyme that maintains our glucose levels, which in turn, can cause an imbalance with our other hormones and trigger those red, bumpy friends of ours to come on our skin. When we eat more sugary/salty foods, our body gets dehydrated and produces more oil to combat this dryness. Because of this, our skin’s sebaceous glands will secrete more oil, clogging our pores and causing even more acne! The cycle seems pretty straightforward: the more junk food we eat, the more negative effects occur as our body goes haywire and tries to bring our hormone and oil levels to a normal level, and one of the ways we can see this is really through the health of our skin.
Now let’s talk about foods that can help our skin glow. Foods rich in omega 3 fatty acids, as they help preserve collagen in our skin. These include flax seeds, fish and walnuts, so make sure to include those in your diet. Foods with Vitamin C are wonderful sources of antioxidants and help with fighting the free radicals that come in contact with the surface of your skin, which can damage your skin. Foods that have vitamin C include oranges, bell peppers and strawberries. Overall, including a healthy mix of different fruits and vegetables will help your skin become smooth, soft and plump.
So all in all, if we cut out the sugar, we can potentially save ourselves from hundreds of dollars spent on the latest skincare, pimple patches and dermatologist visits. Our skin is a reflection of the things we put in our body and our internal environment. If we keep our internal body clean, our external body will showcase that. So the key, I believe, lies in the age-old mantra our parents and grandparents have peddled to us since we were kids: You are what you eat. So eat “clean” kids, take care of your health, and see your skin glow!
Early at 8 a.m. after studying all night and after a couple more classes, you get to your comfy bed, and your mind can only focus on one thing– a perfect midday nap. Naps have become a staple for me this quarter, but it has thrown my sleep schedule off. You know, when you stay up well past midnight once, and then, it ends up being a part of your daily routine. I can’t help but wonder if my fragmented sleep schedule is why I can hardly focus in class or why my social battery is so low.
So how come naps are so enjoyable if it can throw off your sleep schedule? Or wait… does it even affect your sleep schedule? Well, to find out, it is important to understand the circadian rhythm, also known as the body’s “internal clock,” and how it affects the sleep-wake cycle. The sleep-wake cycle majorly affects human productivity, and with an improper sleep schedule, it makes it difficult to carry out your daily life.
It begins with the biological rhythms
Circadian rhythms are often referred to as a biological clock, but what does that really mean? Rhythms refer to the physical, mental, and behavioral cycles that occur within 24-hour periods. This is important in allowing the body to carry out its daily functions at appropriate times such as hormone release or maintaining body temperature. For example, body temperature drops at night, signaling the body that it needs to rest. The body aligns its rhythms with day and night with the help of light, which is processed in the hypothalamus. The hypothalamus is located in a deep region within the brain, and I could go into depth on all of its functions, but that would be its own separate blog. Most importantly, the function we are going to focus on is how it manages sleep with help from the suprachiasmatic nucleus (SCN). The SCN is a bilateral structure inside the hypothalamus composed of about 20,000 nerve cells that receive synaptic input from the eyes. A bilateral structure is symmetrical, and this is important for the SCN so it can properly function in both hemispheres of the brain to efficiently operate circadian rhythms. With direct input from the eyes, light is processed, and signals can be sent to the body to infer that it is daytime, allowing the SCN to specialize in managing the human body’s internal clock.
To better understand how light processing maintains circadian rhythms, let’s use jet lag as a quick example. For most people, flying across the world results in a couple of days of jet lag, where your body has yet to adapt to a new time zone, so your sleep-wake cycle is still aligned from wherever you originally took off from. This is because the body is adapted to using light as the primary signal to awaken and begin performing its daily routine and functions. So, when you are in a new time zone and day and night are switched, it takes time for the body to adjust to the difference in light, having to change the circadian rhythm timing.
Stages of sleep and GABA
Circadian rhythm is all about cyclic oscillations, especially with the stages of sleep. While there are multiple stages of sleep, there are two main categories: rapid eye movement (REM) sleep and non-REM sleep. The stages of sleep are regulated with the help of GABA, and it is vital to understand what it is and how it works before we dive into the different stages of sleep.
GABA is an inhibitory neurotransmitter that regulates circadian rhythm, especially with sleep and stress. GABA binds to its receptors and inhibits other neurotransmitters from responding to small stimuli. Since GABA hyperpolarizes the neurotransmitters that would respond to these stimuli, it increases the threshold needed to fire an action potential. Depolarization is what allows the firing of action potential, so when cells are hyperpolarized, positive ions flow out of the cell membrane so that it can not reach the threshold. This can be used to interpret why GABA is so important for sleep and stress regulation. Think of it to ease the mind from constantly firing responses to small stimuli, reducing anxiety, and allowing the body to respond to signals that it is time to sleep. Insufficient amounts of GABA may lead to sleep disorders, the most common one being insomnia. An 8-week study was conducted to monitor the relationship between GABA and sleep, where individuals who were unable to get proper sleep were treated by consuming capsules that contained GABA. The results of this study confirmed that GABA does have a strong influence on circadian rhythms as participants noted that their sleep schedules did improve, where they experienced longer, preferred amounts of non-REM sleep.
Beginning a sleep episode of multiple cycles, first you go through stages one to three of non-REM sleep. Non-REM sleep accounts for around ¾ of time asleep and involves the relation between the brainstem with the thalamus and cortex. During non-REM sleep, GABA hyperpolarizes the neurons in the thalamus and cortex. Each stage of non-REM sleep varies in time, where they progressively get longer. To start, stage 1 of non-REM sleep is the shortest, lasting just a few minutes and can easily be disrupted. Stage 2 of nonREM sleep gets longer as the cycle repeats and accounts for around half of total sleep. Stage 2 is where you enter a progressively deeper sleep, until stage 3 which is the deepest stage. Stage 3 is where you are in a deep sleep called slow-wave sleep (SWS), lasting anywhere from 20 to 40 minutes.
Next is REM sleep, which lasts only a couple minutes the first cycle but progressively gets longer as the cycle repeats. This is the stage of sleep where you visualize most of those bizarre imagery and scenarios that you can hardly recall in the morning, aka dreams. REM sleep is by far the most interesting stage, as dreaming causes rapid eye movement and brain activity that is like when awake. On average, REM sleep repeats 4-5 completed cycles each sleep episode.
Prolonged effects: Insomnia
Maintaining circadian rhythms with the sleep-wake cycle is vital to carry out daily functions. Improper sleep causes complications in productivity, which can be called worker fatigue. This fatigue refers to the mental state between being awake and asleep. Worker fatigue differs from simply being tired, where prolonged inadequate sleep and disruption in the circadian clock creates more drastic effects in individuals. This fatigue involves the mind not being able to carry out daily functions including reaction time and problem-solving abilities. This may also result in problems with the immune system and can lead to long-term health issues.
Insomnia is the most common sleep disorder where an individual struggles with falling asleep or staying asleep. In 2011, a study was conducted to see how prevalent insomnia is in the U.S. while demonstrating its significant impact on productivity levels. The results concluded that an estimate of 23.2% of the population experienced insomnia, contributing to decreased work performance which results in $63 billion lost annually. This study illustrates how insomnia impacts the economy but can also be used to demonstrate how it commonly affects people. As previously mentioned in terms of productivity, individuals with insomnia are unable to perform daily tasks and instead struggle throughout the day with fatigue.
So, yes or no to naps?
Understanding your circadian rhythm is crucial as it maintains your internal clock. Aligning your day-to-today life with circadian rhythms boosts your health, productivity, and overall well-being. Where the body specializes in being able to function on its own, it is still our responsibility to align our activities with our rhythms to maintain a healthy lifestyle. At the beginning of this blog, we asked if naps are harmful to circadian rhythm. I do not believe that there is a clear answer after learning about the intricacies of sleep; longer naps can lead to disordered circadian rhythms as waking up in a deep stage of sleep can cause an abrupt change in brain activity from slow to active. However, shorter naps do not tend to reach the state of deep sleep and brain activity during a catnap can still resemble itself when awake. In addition, sleeping during the day may cause disturbances to light-to-signal processing. However, after taking a closer look at an example of a common sleep disorder, these imbalanced patterns are caused by prolonged disturbances. My opinion? A nap everyday may not be ideal, but a once-in-a-while post-class nap never hurts anyone.
Sources
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707128/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527439/
https://www.cdc.gov/niosh/mining/works/coversheet2049.html
https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx
https://www.ncbi.nlm.nih.gov/books/NBK19956/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157657/
https://unsplash.com/photos/a-bed-with-white-sheets-and-white-pillows-pl3sj3DigxM
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What is Yoga?
Although the modern practice of yoga was recently made public to the masses in the last few decades, “Yoga” has been a common practice of those in the Indian subcontinent since 2700 B.C, originating in the Indus Valley. The word “Yoga” is derived from the Sanskrit root “Yuj”, meaning “to unite”. In essence, yoga aims to unite the mind and body with the ultimate goal of reaching self-realization, a state where the body is free or liberated from suffering of the material world. Freedom from suffering guides traditional practitioners of yoga towards achieving a balance of health both in the body and the mind. During the Classical Period of Yoga, from 500-800 B.C., the eightfold path of Yoga was developed, consisting of components like posture, breathing, asanas (poses), and self-discipline. These physical components formed the backbone of the yoga that is still practiced today, leading the practice towards enlightenment. In this respect, Yoga is associated with “the art and science of healthy living”. However, while yoga simply unites the body with the mind, the spiritual aspect of yoga cannot be understated, as it is a lifestyle that many adopt to “harmonize oneself with the universe”.
Is Yoga Just A Workout?
Yoga began as a spiritual practice, but is mainly known today for the physical benefits as a daily exercise. In the early 20th century, many swamis, or spiritual teachers, started to introduce their teachings to the West. Swami Vivekanada arrived in the U.S. with the goal of making yoga more accessible to Western populations through live demonstrations and translations of sacred Sanskrit yogic texts. As more swamis ventured to the Western world to open more traditional schools of yoga, more people began adopting yoga into their lifestyles. However, these forms of yoga were mainly restricted to the asanas. Most people might know the common postures such as “child’s pose” and “downward dog”. While these forms of yoga are fundamentally important, many Westerners began to simplify yoga down to only these two forms. These days, many yoga classes view yoga as a method of exercise, meant to initiate a sweat, burn calories, and tone the body, while cherry-picking bits and pieces of true yoga. At most, many of these classes will finish with a final breathing session, but to the true practitioners of classical yoga, it is less an homage than it is a weak recreation of an ancient form of meditation.
Yoga and Pain Relief
Emphasizing the history and meaning behind yoga does not mean one should negate the obvious physical benefits it provides. The physical characteristics of yoga are extremely important to understanding the utility of this ritual. These acts also lend yoga to being a useful form of physical relief for people suffering with chronic pain. According to Harvard Medical School, four in five Americans suffer from back pain. However, a 2015 study by Journal of Physical Therapy found that when completing 90-minute sessions of Hatha Yoga per week, which focuses on stretching and breathing techniques, spine mobility in elderly women significantly improved. Osteoarthritis is another common condition that results in joint stiffness and long-term pain due to age-related degradation of cartilage and joint linings. A 2014 study by Harvard Health discovered that women who completed an hour session of yoga per week resulted in a “38% reduction of pain and a 35% reduction of stiffness”. While elements of yoga such as frequent stretching and focus of flexibility promote low-impact movements necessary to alleviate chronic pain, is there a scientific reason for these results? A 2008 study done by researchers Sarika Arora and Jayashree Bhattacharjee for the International Journal of Yoga show that yoga does indeed lower the activation of the sympathetic nervous system, which is known for its role in “fight or flight” stress responses and lowering heart rate, cardiac output, and blood pressure. Practicing yoga also inhibits the posterior hypothalamus to reduce stress responses. This suppresses the release of adrenocorticotropic hormone from the anterior pituitary gland, which is responsible for helping release cortisol, a major stress hormone.
Yoga and Depression
Although many choose to focus on the physical and athletic characteristics of yoga, the mental relief it provides should not be overlooked. While some people may believe meditation is an act of stillness, yoga uniquely allows meditation to occur through movement. According to the World Health Organization, major depressive disorder is the leading mood disorder, afflicting over 280 million people around the world. Depression results in anhedonia (loss of pleasure), persistent sadness, lack of energy, and feelings of guilt and worthlessness. The cause of depression may be through external factors such as stressors from work, home, or school, or it may be genetic. No matter the cause, depression has become widespread and greatly affects the mental health of those who have it. Some researchers looked into the benefits of yoga to alleviate the symptoms of those with depression. In a review completed in 2017 by Alternative Medicine, researchers concluded that the preliminary evidence of yoga reducing depression was hopeful due to the focus on “mind-body interventions” by helping patients control their breathing, relax, and learn self-regulation. More specifically, another review by Explore: The Journal of Science and Healing suggests that yoga has been shown to “modulate stress-responsive brain regions including the amygdala, hippocampus, and hypothalamus, to improve hypothalamic-pituitary-adrenal (HPA) axis activity, autonomic balance, and inflammation, reducing drive on bottom-up stress pathways”.While yoga should not replace traditional medicine to treat mental disorders, yoga is a useful supplementary method when paired with typical pharmacological approaches.
Despite starting as an ancient form of meditation and self-realization, yoga can be studied for its vast physical and mental benefits. Not only is yoga a useful way to move the body, especially for those experiencing chronic pain, but completing a yoga routine provides solace and calmness to those experiencing stress and mental health issues. However, purely viewing yoga from a dichotic lens does not lend itself to understanding the rich and complex history of this form of prayer. To practice yoga is to recognize a culture and a people and honor a tradition that has enhanced the lives of many throughout generations. Appreciating yoga for its many benefits, not just the ones found in a workout class, is an art that will hopefully be sustained and remembered for future generations.
References
https://www.health.harvard.edu/staying-healthy/the-physical-benefits-of-yoga
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4339138/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144610/
https://www.cnn.com/2023/05/17/health/depression-rates-gallup/index.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871291/
https://pubmed.ncbi.nlm.nih.gov/36239640/
https://yoga.ayush.gov.in/Yoga-History/
https://unsplash.com/photos/silhouette-photography-of-woman-doing-yoga-F2qh3yjz6Jk
]]>Scientists have always utilized creative approaches to study the brain. Live animal, or in-vivo, studies look at the real time behavioral consequences of neural manipulation. For years, to study specific brain regions, researchers would damage the specific area and study the animal’s consequent behavior to understand the importance of the region. As technology improved, scientists became able to genetically alter neural circuits; a more precise and less risky approach in comparison to removing functional brain regions. These techniques allow scientists to target specific cell types, circuits, or whole areas without risking damage to other areas of the brain. Genetic manipulation, knockouts, and lesion studies prove to be compelling in neuroscience, however, most of these experiments are slow, invasive, and typically permanent. No simple way existed to get fast, precise control of neural activity that could be turned on and off, until Karl Diesseroth’s lab at Stanford University developed optogenetics.
What is Optogenetics?
Optogenetics combines light (‘opto’) with genetic modifications (‘genetics’) in order to create an experimental setup in live animals where modifications can be turned on and off as needed. The idea behind optogenetics is simple: make your subject (usually a rat or mouse) express an ion channel in the brain that is sensitive to light. Neurons transmit signals via the opening and closing of ion channels, thereby influencing their electrical activity. If light is delivered to one of these special ion channels, called an opsin, the cell can be activated or inhibited, depending on the needs of the experiment.
The first step in any optogenetic experiment is to induce expression of opsin. Light-sensitive channels were initially discovered in bacteria, but thanks to genetic engineering, it is possible to make almost any cell express these channels. There are several ways to achieve this; such as using genetically modified rodents, or by delivering a virus that contains DNA for the ion channel to the subject. Today, many types of opsins are available to suit the needs of any experiment. Two of the most common types are channelrhodopsin, a blue-light sensitive excitatory ion channel, and halorhodopsin, a green-light sensitive inhibitory channel. For example, if there was an animal expressing both Channelrhodopsin and Halorhodopsin, delivering blue light would cause its neurons to fire while delivering green light would inactivate them. By utilizing different genetic characteristics, opsins can be optimized for specific cell types, brain regions, or activation/inactivation speeds.
After an animal expresses the opsin, researchers implant a fiber optic cable in the brain. This cable attaches to a light source that delivers light at the wavelength responded to by the channel, usually blue, green, or red, depending on the opsin. The light source, usually a laser or an LED, switches on and off and ion channels operate within milliseconds. This means that these circuits can be turned on and off completely, literally with a flick of a switch.
Memory Studies
One of the most innovative uses of optogenetics is in memory studies. A common behavioral test known as conditioning reveals the mechanisms behind memory systems, and relies on the hippocampus. Conditioning results in associative learning, where an animal earns to associate two independent stimuli. A subject’s ability to predict a second stimulus after exposure to the first indicates if associative memory was affected by an experiment. A scientist will train the subject to two stimuli, such as a high-pitched tone (the “conditioned” stimulus which normally would not evoke a behavioral response) and a puff of air to the eyes (a response-evoking “unconditioned” stimulus). If learning occurs, after training, the subject should automatically react to the unconditioned stimulus, in this case by closing the eyes upon hearing the high-pitched tone. This is called eyeblink conditioning.
The process by which the two stimuli are associated is called long term potentiation (LTP). When learning occurs, synapses at neurons within a memory circuit strengthen, resulting in transmission of more neurotransmitters and increased sensitivity of the postsynaptic neuron. LTP explains how associations are made during conditioning experiments. After a period of time, depending on the strength of LTP and the degree to which a memory has been reinforced, synapses may be desensitized and weakened through a process called long term depression (LTD). This allows unnecessary connections to be lost so that new memories can be made and stored, essentially how forgetting works.
But what does this have to do with optogenetics? If a scientist wants to study the importance of a certain brain region or synaptic connection in learning, they can perform an experiment in which they inhibit or activate the area of interest only during conditioning. If an area gets optogenetically modified during a behavioral experiment and learning outcomes are affected, this demonstrates precisely an important link between the area and learning. Experiments like these enable the animal to have a normal life outside of the experiment, and help to establish causal relationships between synaptic processes and memory.
How UC San Diego Scientists Engineer Memories
One of the most famous optogenetic memory experiments was conducted by Sadegh Nabavi in Roberto Malinow’s lab here at UC San Diego. Animals were conditioned using a classical conditioning method: a tone paired with foot shocks, eliciting an easily measurable fear response. Upon hearing the tone, subjects produce a fear response, indicating learning occurred. This is a common and simple technique, but the Malinow lab did something new: they replaced the tone with excitatory light delivery to the auditory cortex, activating the auditory stimulus response without the actual stimulus being present. Pairing optogenetic stimuli with a fearful stimulus induced LTP in the animal in the same way that a tone typically would. Furthermore, inducing LTD by optogenetic stimulation resulted in a loss of the fear response. Synapses can be desensitized by weak, prolonged exposure to the conditioning stimulus, resulting in synaptic depression and loss of the memory association. By precisely activating and inactivating specific neuronal assemblies, the inner workings of memory circuits are revealed.
How are Optogenetics Being Used Today?
As optogenetics becomes easier, more affordable, and more widely used in labs, our understanding of brain circuitry continues to rapidly develop under more precise and innovative techniques. One of the most straightforward ways to study whether a certain synapse, cell, circuit, or region within the brain is needed for learning is to inactivate it and identify whether memories are still formed. The precise temporal control offered by optogenetics allows experimenters to use this general idea while opening up the field to even more questions to be uncovered. For example, perhaps a scientist wants to know exactly what time window is important for memory formation. The experimental procedure would be as follows: inhibiting the hippocampus (or any brain region involved in learning) during the training period for the conditioned stimulus, unconditioned stimulus, or the period in between. This can be easily done with an inhibitory opsin, like halorhodopsin, and brief light delivery at a chosen time point. The lack of a conditioned response after light delivery at one of these experimental timepoints would indicate that a memory has not been formed, and that LTP is dependent on that timepoint.
New applications for optogenetics are being developed every day by labs across the country. Some labs are enhancing memories to treat disorders like Alzheimer’s disease, while others have successfully implanted false memories and used induced LTP to recover “lost” memories. Though some time remains before these technologies are ready for human applications, the budding field of optogenetics offers innovative research leading to promising therapeutics for memory disorders and beyond.
Sources:
https://unsplash.com/photos/human-brain-toy-IHfOpAzzjHM
https://www.nature.com/articles/nature11028
https://www.nature.com/articles/nprot.2009.226
https://www.nature.com/articles/nature13294
https://www.jove.com/t/51483/in-vivo-optogenetic-stimulation-of-the-rodent-central-nervous-system
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Stem cells are unique from other cells because they are unspecialized and have no set function in the body like a blood or muscle cell, but they do have the ability to develop into a variety of different types of specialized cells in the human body. There are two main types of stem cells that are currently well-understood: embryonic and adult. Embryonic stem cells are cells extracted from early embryos that are pluripotent, which means they can differentiate into any cell type in the body. Adult stem cells come in two forms, the first being from tissues in the body, like skin or brain tissue, and will only differentiate into specialized cells from the tissue in which they originate. For example, stem cells from skin tissue will turn into more skin cells, not other types of cells such as neurons. The other type of adult stem cells are known as induced pluripotent stem cells—the term ‘induced’ stems from the fact that they have been modified in a laboratory to act more like embryonic stem cells. Induced pluripotent stem cells can differentiate into more than one type of cell in the human body.
Image: Visual representation of stem cells transforming into specialized cells
The Future of Developmental Biology: Synthetic Embryos
In a study done at the California Institute of Technology, Magdalena Zernicka-Goetz, a Polish developmental biologist, and her colleagues were able to use the stem cells of mice to create synthetic embryos in a manner similar to how bacteria are cultured. First, they placed mouse embryonic stem cells and extraembryonic stem cells (found outside the embryo) into well plates. These are similar to the Petri dishes that bacteria tend to be cultured in because they hold the necessary media for cell or bacterial growth and formation. While an agar medium promotes bacterial growth, several different media including FC, IVC1, DRH, and EUCM—all of which provide nutrients and other growth factors that aid in both embryo and stem cell culture—were used to promote the aggregation of the mouse stem cells into the desired synthetic embryos. In addition to requiring specific media, the cells required specific oxygen conditions (21% oxygen provided continuously or slowly increased from 5-21% over the incubation period) to further aid in embryo development, just like how bacteria are incubated at specific temperatures to help colonies grow. The fully-formed synthetic embryo models exactly replicated natural mice embryos up to 8.5 days after fertilization, and they contained both brain and heart structures. Jacob Hanna, a professor of stem cell biology at the Weizmann Institute of Science, conducted a similar study: instead of using well plates, Hanna and his team developed an electronically controlled embryo culture platform that supports stem cell assembly into embryo structures containing hearts, brains, neural tubes, guts, and germ cells. This electronic machine is made up of similar plates used in the previously described study; however, it can rotate and has customized gas and pressure regulation modules to better control the incubation period.
The successful results of Hanna and Zernicka-Goetz’s studies have enormous implications for the future of the reproductive and developmental biology fields. First, these synthetic models could replace the use of lab animals in studying early developmental stages and concepts of early development like infertility and pregnancy loss. However, there are still several limitations to this research: for example, Zernicka-Goetz’s synthetic embryoids—a structure that resembles an early-stage embryo created in a lab—are unable to survive to term, which is 20 days for mice. Hanna’s study had a similar issue, indicating that improvements need to be made to these two cell culturing methods. Getting these embryos to term would be vital for studying the later stages of development. Furthermore, there are several ethical and societal implications that must be explored and discussed before creating artificial human embryos. For instance, a current controversial debate in the bioethics community is whether or not research on synthetic embryos should be allowed past the 14-day limit set for actual embryos. This begs the question of whether or not artificial embryos should be treated as ‘life,’ significantly if they could eventually develop into living persons, like actual embryos.
The Future of Fertility: Same-Sex Conception
In addition to the development of synthetic embryos, stem cells have also aided in the creation of mice pups from two male mice. Katsuhiko Hayashi of Kyushu University and Osaka University in Japan accomplished this by converting the adult skin cells of male mice into induced pluripotent stem cells. These were then transformed into female egg cells through treatment with a drug named reversine. The eggs were then fertilized and transplanted into the embryos of female mice. 7 of the 630 embryos survived and developed into mice pups that could live on and reproduce as normal. While this is a low success rate, this is only the first study of its kind. More research is needed to truly determine if this is a viable method of conception. If it is, it could have many positive consequences. For example, it may be possible to reproduce endangered species—like the orangutan, the Asian elephant, the blue whale, the chimpanzee, the red panda, and the sea turtle—from a single male in the future.
In addition, stem cell embryos could increase the alternative fertility and reproductive options for couples who cannot naturally conceive, while potentially eliminating the negative ethical challenges of donor eggs: the principle of justice and respect for autonomy. The principle of justice is a medical ethics term that refers to the fair and equitable distribution of medical access and opportunities; in this case, donor eggs. Currently, donor eggs are more likely to go to those who can pay more for them, not necessarily those who are more fit to be parents. Likewise, respect for autonomy is another phrase commonly used in discussions of medical ethics to describe an individual’s right to make informed decisions about their own body. As of now, egg donation is highly unregulated, and donation agencies often do not properly explain the emotional, physical, and psychological implications and risks of the process to both donors and recipients. Additionally, their websites often contain predatory language to manipulate those in financial need to donate their eggs or those desperate for children to start the recipient process. For instance, a study done by Lindsay Gezinski, an associate professor of social work at the University of Utah, found that donation sites use highly emotionally-charged language compared to neutral medical terminology to describe the process of egg donation (e.g. 9 of the 19 sites studied used the phrase “the gift of life,” which is non-scientific diction). The characteristic messaging of these websites tends to neglect considerations for health complications that may occur through egg donation. One somewhat common complication is the development of Ovarian hyperstimulation syndrome—a condition characterized by the swelling and leaking of ovaries. Although most cases of ovarian hyperstimulation are mild and treatable (i.e. abdominal pain that will resolve itself within a week or two), some cases can be critical with symptoms like difficulty breathing and kidney failure.
Even though there is still much research to be done, it seems as though stem cells are the key to many future medical advancements. Not only could they be effective in treating different diseases or cancers and replacing damaged tissues in the body, but they could also aid in the betterment of both developmental and reproductive biology. The decreased use of lab animals in research, the potential for a better understanding of issues regarding infertility and pregnancy loss, and the ability for same-sex child conception are all incredible advances that would improve both science and quality of life. The studies conducted by Zernicka-Goetz, Hanna, and Hayashi are just the beginning, and much more research regarding stem cells in these fields should emerge within the next few years. Although yet to be fully realized, the nature of stem cells holds great promise for the future.
Sources:
Through current media, we are constantly reminded of the threat food insecurity places upon the future of our planet. According to Natural Geographic, the Earth needs to feed two billion more people by 2050. What this really means is that if current trends in human diets remain unchanged, the world would have to grow double the current amount of crops, not only to feed the larger population but also the livestock that will need to be bred for human consumption. These numbers are concerning for a world already suffering from damages of raising livestock. Current estimates highlight that raising livestock uses up to 70% of our agricultural land and contributes to about 15% of the world’s global greenhouse gas emissions.
Another increasingly prevalent issue is the increased energy use experienced in recent years. Studies have shown that worldwide GDPs are increasing, which means that the average individual will be able to afford gas vehicles, increasing the usage of petroleum, a nonrenewable resource. Increased energy consumption requires the combustion of fossil fuels such as diesel and petroleum. Currently fossil fuel combustion accounts for 73% of green house gas emissions. With the two aforementioned problems expected to worsen in coming years, scientists are looking towards an unlikely source, algae, to save the world.
Algae in Our Food
Algae is already implemented in a significant portion of many human diets. It exists in a number of dairy products to help with fermentation. The ingredient is implemented in cereal based products like pasta, often to increase the fiber content of the dishes. However, research suggests that algae can be much more than a supplemental ingredient.
Firstly, it is important to distinguish between macroalgae and microalgae. Macroalgae are those visible to the human eye whereas microalgae are those that are too small to see without the help of a microscope. Despite its small size, microalgae is the more exciting of the two when comparing their value to human diets. Since algae do not have stems, roots, or branches, they can focus on producing proteins and fatty acids instead of cellulose.
Algae’s most impressive nutritional impact is its high protein content , which is most notably used to build and repair muscles. It contains all nine essential amino acids, those that cannot be produced within our own bodies and must be obtained through food, at similar or higher levels than crops such as soybeans and wheat. Through the five strains of amino acids tested, aspartic and glutamic acid had the highest rates of amino acid content. Aspartic acid assists both in energy production and in chemical signaling to the nervous system. Glutamine is the only amino acid that offers assistance in both muscle formation and cellular support. Through all five algae strains, the amino acid content of the nine essential acids were comparable to the rates of these acids found in soy protein.
Additionally, many forms of microalgae offer high concentration of lipids, important for signaling and cell membrane structure. This comes primarily through omega-3 fatty acids, an essential fatty acid that humans must receive from food. These fats are essential to the function of cell membrane receptors throughout the body and are involved in producing hormones that regulate blood clotting and inflammation.
There are two studies which truly highlight the importance of omega-3 fatty acids. The GISSI prevention trial, conducted in the late 1990s, focused on the effect of omega-3 fats among heart attack survivors. The group that consumed a gram capsule of omega-3 fats every day for 3 years had a reduced rate of repeat heart conditions compared to those who were given a placebo. Similarly, in the Japan EPA Lipid Intervention Study, participants who took statin (a common drug used to reduce cholesterol) along with EPA (a type of Omega-3 fatty acid) had a smaller chance of having a serious heart condition, such as a heart attack, than those who only took the statin. Additionally, omega-3 fatty acids can prevent heart conditions and stroke while also mitigating the effects of other conditions, such as lupus and eczema. Through the increased intake of protein and particular lipids such as omega-3, it is clear that algae offers much to the betterment of human health.
Still, what separates algae from our current sources of protein and omega 3-fats is its sustainability. As I mentioned earlier, soybeans are currently regarded as the best protein producing crop. However, algae is able to grow on land where other plants typically cannot grow, such as deserts using waste water, meaning that these resources can be saved for other purposes. Even in these conditions, algae can produce protein at 20 times the amount of soybeans. The dry protein mass of soybeans ranges from 35-45 percent, while algae ranges from 27-70 percent.
It may not be long until algae becomes a part of our diets. Triton Algae Innovators is a San Diego based company that has been experimenting with microalgae-based ingredients using the algae strain, Chlamydomonas. Some of the company’s most recent recipes include pastas, beverages, crostinis, and even dumplings!
Algae in Our Engines
The benefits of cultivating microalgae do not stop at its nutritional value. In recent years, biofuels have been introduced to the energy market to offer an additional form of energy to meet increased demands in an environmentally-friendly manner.
Microalgae are considered a good source for biofuel because they can grow rapidly compared to terrestrial crops, which biofuels are traditionally derived from. Most of the natural oil produced by algae is triacylglycerol, which is the ideal oil for producing biodiesel, diesel fuel procured from plants, due to its chemical similarities to non-renewable diesel. Additionally, the carbohydrates that microalgae generate can be fermented into biofuels such as ethanol and butanol. Algae biofuels have the opportunity to replace our current fuel options, and we wouldn’t even need to change our engines.
The growth of algae provides an exciting new option within the sector of biofuels. Just a single acre of algae can produce upwards of 30 times the amount of biomass as well as 60 times more oil than other land based biofuel options such as corn.
How to Grow Algae
Currently there are two major options for growing algae, the first being photobioreactors. Photobioreactors, typically shaped as a tube, are an enclosed container in which algae biomass grows. Developers hoped that through this enclosed system, evaporation would be reduced along with interaction with other algae species and predators. Photobioreactors have provided great results: A 2007 study discovered that photobioreactors can generate up to 13 times the amount of biomass as open raceway ponds, the currently more conventional method to growing algae. One microalgae farm in Iceland uses LED lights and fills the photobioreactor tube with waste water and carbon dioxide to ensure that the microalgae receives all necessary nutrients for growth. The facility has a negative carbon footprint and is able to go without herbicides, pesticides while maintaining zero waste during the production process.
The second option to grow algae is to use outdoor man made pond systems. The temperature of the pond must be maintained at around 60-80 degrees Fahrenheit with a pH of 7-9, although there are slight variations based on the type of microalgae used. The algae cannot settle at the bottom, so paddle wheels are set throughout the pond to ensure constant mixing. Typically, open pond’s are in a race car track formation (a large oval with a smaller divider in the middle) earning it the nickname of a raceway pond. This structure allows for large amounts of surface water where the algae can receive sunlight while also limiting the amount of land required.
However, there are concerning limitations to the open pond system. Since the pond has to be outdoors and exposed to sunlight, there tends to be significant amounts of evaporation experienced, thus reducing the amount of algae that can be produced. Another problem is that open ponds are exposed to bacteria and fungi predators, such as Vampirovibrio chlorellavorus which degrades algae proteins. These predators can destroy a fully functioning pond overnight.
Interview with Dr. Pomeroy
In order to further understand how microalgae can be grown and harvested, I interviewed UC San Diego professor and previous Revelle Provost Dr. Robert Pomeroy. In addition to his other commitments, he works for the California Center for Algae Biotechnology (CalCAB) and currently leads a lab where his team produces items out of algae for purchase, such as flip flops and surfboards!
When asked whether photobioreactors could be a potential option for large scale microalgae growth, he claimed that the algae produced in these bioreactors come in too small of a quantity and are too expensive to produce due to the maintenance required to keep the bioreactors functioning. Hence, Dr. Pomeroy suggested that open pond systems, due to their smaller cost, were a much more viable option to grow algae.
As Dr. Pomeroy began working with raceway ponds, he noticed that pond collapse was an increasingly prevalent issue, and he began looking into a solution. He discovered that before pond collapse would occur, whether by a predator or infection, there would be a minute change in the smell of the pond. To detect these changes, he helped develop a mass spectrometer with a sampler that can sit on the surface of raceway ponds and collect glasses. This way, it can help notify changes in the biochemistry of the air and atmosphere to help identify an infection. Normally, this method would have to be done with microscope and PCR testing and, as Dr. Pomeroy stated, “is expensive and lacks sensitivity. It could take up to two days to get results back. Meanwhile, some preliminary results for the spectrometer have come back in as quick as three hours.” He stressed that it is crucial to be immediately notified after infection because algae can be harvested at any point in production. Dr. Pomeroy explains “This is different from a majority of crops such as wheat, which you cannot harvest until it is fully grown.” Hence, one can pull the plug on the pond and harvest all the algae they have grown before all the algae is destroyed in the collapse.
Dr. Pomeroy also pointed out that his colleague, Dr. Stephen Mayfield, has been looking into other potential solutions to ensure pond success. Dr. Mayfield understands that if his team could discover a strain of algae that could grow at high pH levels and high temperatures, it would prevent predators and bacteria from infecting the pond because it wouldn’t be able to survive in those conditions. Dr. Mayfield quickly discovered that genetically engineered strains of algae could live in these extreme conditions, but due to environmental regulations within the United States, these engineered strains aren’t allowed to be grown outside. However, his team is allowed under regulations to mutate the algae to the point to which it developed into the strain type that could survive extreme conditions. To mutate algae, Dr. Mayfield and his team exposed the algae to UV light, which would damage the DNA and cause a mutation to occur. This is because the UV radiation oxidizes DNA bases, causing it to pair incorrectly during the replication process. These errors in the replication of new strands cause the development of new traits, known as mutations.
Another method for Dr. Mayfield’s team to discover an algae that could survive in extreme conditions was to selectively breed different strains of algae. Different types of algae with genetically favorable qualities could take part in sexual reproduction to produce a strain with even more advantageous qualities. This process would then be repeated till eventually a strain was developed that would be able to perfectly withstand the harsh conditions and grow quickly. Both of these aforementioned methods developed by UC San Diego researchers are pivotal in making algae a more viable food and biofuel source in the future.
But how do we harness algae’s energy as biofuel? The answer is in oils! As the algae grows in either an open raceway pond or a photobioreactor, it stores its energy as natural oils within itself. The oil is extracted by breaking down the cell structure of the algae, either through solvents or sound waves and then sent to a biorefinery to be processed. The natural oils have now become biodiesel and can be used in engines of cars, planes, and other motor vehicles.
An additional advantage to utilizing algae is its ability to play a role in carbon sequestration. Many forms of algae are photoautotrophic, meaning it requires photosynthesis to produce sugar and energy for itself. As a result of this process, algae sequesters carbon dioxide from the atmosphere. Currently, algae is less than two percent of global plant carbon but absorbs up to 50 percent of atmospheric carbon dioxide and converts it into organic carbon. As our world continues to invest more into the production of algae, we can be assured that even more atmospheric carbon would be able to be absorbed. Algae farms could be located near industrial pollution sources, such as carbon-producing refineries or power plants, and help clean the air by consuming carbon dioxide as they grow.
Our problems of food insecurity and climate change can be mitigated through the help of a plant we can’t even see. As we age and reduced resources are used for our food and less carbon is produced from our fuel, you can gaze at the sea with confidence that future generations will get to experience a beach with wide layers of sand and clean air.
Links:
https://www.nationalgeographic.com/foodfeatures/feeding-9-billion/
https://escholarship.org/uc/item/7jb0015q
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8125830/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893549/
https://www.frontiersin.org/articles/10.3389/fnut.2022.1029841/full
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)90191-5/fulltext
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931876/
https://agsci.oregonstate.edu/sites/agscid7/files/bioenergy/education/algae_final_interactive.pdf
https://www.sciencedirect.com/topics/engineering/open-pond
https://www.sciencedirect.com/science/article/abs/pii/S2211926421000680
]]>Stem cells are cells that have not yet differentiated, or changed, into cells with unique structures and unique functions. Differentiation can be triggered by several factors, such as environmental cues. Stem cells within the central nervous system, known as neural stem cells (NSCs) turn into different kinds of neural cells. At the pluripotent stem cell stage, or the stage where the stem cell is still immature, differentiation into multiple types of matured cells can be highly controlled. Having this controlled differentiation into specific neural cells such as neurons and glial cells– a type of neuron-support cell– allow many scientists to use stem cells to grow cells as needed. This technique has been included in studies to advance knowledge on neurological disorders such as schizophrenia, Parkinsons, and Alzheimers, among other disorders.
Schizophrenia:
Schizophrenia is both a psychiatric and neurological disorder that is largely influenced by an individual’s genes. A 2019 study used stem cell technology to predict possible genetic contributions to schizophrenia pathology. This disorder is a particularly complex one to study because contributing mutations lie in the noncoding regions of the gene, or the parts of the gene that are not directly expressed but can influence the expression of expressed coding DNA regions. These noncoding regions include promoters, enhancers, and repressors, which control the rate or amount of gene expression through interactions with different coding and noncoding regions in the genome. When an enhancer interacts with a promoter region, gene expression is amplified, but a repressor decreases the rate of gene expression. Furthermore, chromatin—genetic material containing DNA and proteins within each cell—takes on a 3-dimensional and nonlinear orientation known as the 3D genome (3DG). The nonlinear 3DG includes chromatin loops known as TAD loops which help interactions within genes. TAD loops allow promoters, enhancers, and repressors otherwise kilobases apart on a linear line to become within proximity in a loop. This then allows these noncoding regions to interact with each other. However, this long-distance gene interaction is exactly what makes the 3DG and schizophrenia so difficult and complex to study: the presence of TAD loops in the 3DG means that non-coding regions are able not only to interact with the regions closest to them, but also the regions that would otherwise be much, much farther away.
Now, having mutations in the noncoding regions that influence gene expression in the 3DG could mean that the mutations influence more than a handful of coding regions. If the DNA took a linear conformation, only the promoters and enhancers relatively close to each other would interact and cause gene expression. This would make mutations in noncoding regions of the DNA, such as promoter regions, potentially far simpler to identify, and these mutations would not reach as far across the gene. To study genetic interaction in the 3DG, the researchers used a technology called Hi-C to track connections of different genomic regions across the entire genome. Tracking interaction across the whole genome eliminates the bias of picking and choosing which regions to study. This study used Hi-C to focus on presence and intensity of interactions between different regions of the gene with noncoding regions that are known to be at risk for schizophrenia.
From two non-schizophrenic participants, the authors generated iPSCs which differentiated into neural progenitor cells (NPCs), glutaminergic neurons, and astrocytes. NPCs are a type of stem cell that, unlike normal stem cells, have a more targeted range of mature cells they can differentiate into. The glutaminergic neurons of this study are excitatory neurons that keep “passing along the message” to other neurons instead of stopping the chain. Astrocytes are a type of glial– or non-neuronal–cell that specifically resides in the central nervous system (CNS), which includes the brain. Astrocytes are characterized by their star-like formation, regulating the extracellular environment of CNS neurons. By using Hi-C to observe genetic interactions within each specific type of cell, the researchers attempted to derive exactly how schizophrenia might be influenced by interactions between noncoding regions.
Upon using Hi-C to observe the interactions between noncoding regions and TAD amounts, the authors found that of the three cell types, neurons had significantly fewer TAD loops compared to astrocytes and NPCs. However, TAD sizes were larger in neurons. This implied that though there was a lower amount of loops, noncoding regions further away from each other could interact in neurons that couldn’t in astrocytes or NPCs. To further visualize the interactions between noncoding regions of the gene, specifically of at-risk schizophrenia genes, the authors created a heat map to display what Hi-C observed. Heatmaps use color, such as red, to indicate the interaction between gene regions. If there were no interaction, there would be no color shown on the heatmap. In the heat map they created, the more intense the color, the more interaction within or contacting the specific at-risk schizophrenia locus in this focus. Neurons had the greatest amount and intensity of protocadherin (PCDH) interactions and risk locus connection. PCDH are specific molecules that influence neuronal development. Through these and other analyses, it was determined that neurons have the highest risk-contact within their genes compared to astrocytes and NPCs, with schizophrenia-causing at-risk promoters possibly interacting with more genetic regions. From this study, the authors determined that interactions among these risk regions may theoretically contribute to schizophrenia development. This is just one result of the many experiments these researchers conducted in their attempt to understand how interactions within the genome might contribute to schizophrenia.
Schizophrenia is one of many neurological disorders whose research benefited from the stem cell technology invented by Takahashi and Yamanaka. Though this research takes a more theoretical approach to the complex disorder, it provides valuable insight and a promising plan to move forward in our understanding of this neuropsychiatric disorder. Many other disorders are being studied using stem cell technologies, including multiple sclerosis, Parkinson’s, Huntington’s, Alzheimers, and autism.
Below is an interview with Dr. Hiruy Meharena, principal investigator of the Meharena Lab at UC San Diego and professor of UCSD’s undergraduate BIPN 194 and graduate BGGN 284 in the seminar on Stem Cell Models in Neuroscience. He researches the cell-type specific gene-networks and molecular indications behind the development of neurodevelopmental disorders such as Autism Spectrum Disorder and Down syndrome using iPSCs.
SQ: How might stem cells teach us about neurological and neurodevelopmental disorders that also rely on environmental and social factors or other factors than genetic code?
Meharena: I think one of the interesting things about stem cells is because they’re human-derived. You’d be able to provide them with different environmental factors. These environmental factors have to be chemical-based. For example, if you wanted to study how alcohol impacts neurodevelopment, you can start generating a brain in a dish, and then add some level of alcohol and see how that impacts the development of the brain. You can also study environmental factors such as infectious disease or maternal stress. Stress is basically a chemical compound at the end of it. It’s like adding hydrogen peroxide to look at mitochondrial stress and look at how the brain develops.
SQ: How might advancements in stem cell research transform the understanding of neurological disorders and in the clinical application?
Meharena: One of the biggest challenges that we’ve had in the past was that all neurological studies were done on mice or other rodents. Humans and rodents are not similar or the same, so there were a lot of gaps that we were missing in our knowledge about human neurological systems. This includes at the molecular and cellular level, just understanding through development, neuronal function and glia… how are they not only functioning at baseline but how are they interacting with other cell types in their system. Human stem cells now allow us to do that. One of the most difficult things in my opinion has been [ability] to study neurodevelopment. You cannot track neurodevelopment in a pregnant mom the way you’d be doing it with mice, in that we sacrifice mice at different time points and can extract the brain to try to understand what are the specific changes that are happening with high spatial temporal resolution. But now that we have organoids, we can at least somewhat recapitulate that.
(Organoids are 3D tissue samples produced from stem cells)
SQ: What do you think is the most beneficial aspect of combining improvements in stem cell technology with clinical practice?
Meharena: I think we’d need to start with some drawbacks or limitations of stem cell technology, especially in the context of the brain. All the models that we have would allow us to either generate the specific cell types and understand them in a 2D model which is unrealistic– we don’t exist in a 2D model. We’ve advanced to trying to make 3D models. However, the 3D models originate from neural progenitor cells; our brains are constructed of way more than that. We have… cells that have not been fully incorporated into the 3D models that we have today. We have started trying to integrate that, but we’re not there yet. There’s a significant limitation in that regard. The biggest problem is when an organism develops, there are all these different organs [other than the brain]; there are all of the factors that the other organs release, which is not available in that [stem cell] system]. There is a lot of drawback [to this technology] in that we’re still not able to mimic human brain or brain development in our stem cell systems.
There are no FDA-approved stem cell therapies today, but it’s something that’s in progress and the most advanced in that area is neurodegenerative disorders.
(Understanding the limitations of stem cell technologies is necessary to create new research methods or technologies that allow us to surpass them and produce even more effective and accurate results and applications.)
SQ: Do you foresee or are there any major advancements currently being made or considered for stem cell research that may improve its field?
Meharena: The major thing that I think will probably come in the near future is organ transplantation. One of the biggest challenges today in medicine is the limitation of the number of organs that are available for organ transplantation, and even after transplantation there’s rejection and so many different issues on compatibility. However, imagine a world where you can take a skin cell from the patient and make the organ that you need. There are several companies that are attempting to do this. This would be chimeric models with pigs where you take a human stem cell and try to generate the different organs that you need. I think this is probably where we will see some exciting new advancements.
(A chimeric model includes inserting pluripotent stem cells from one individual within a species to another, either of the same or different species, and allowing them to differentiate and grow.)
SQ: Can you tell us about any current research interests or projects that you’re doing right now?
Meharena: My lab is interested in intellectual disabilities… We utilize stem cells to generate organoids and look at how they develop… We have a model that we call “memory in a dish” which is matured neurons where we can activate them… with light… and look at the genetic and molecular changes that happen with neuronal activity. We’re trying to understand how autism and Down syndrome basically disrupt this process.
SQ: Do you have any advice for those interested in conducting research or learning about neurological disorders using stem cells, but may be daunted by the complexity of the topic?
Meharena: I think we’re in a really privileged position here at UCSD because we have the Sanford Center of Regenerative Medicine, and everyone in that building does stem cell research. There are a lot of different labs across campus that are utilizing stem cells, and it’s not just in the field of neuroscience and neurobiology but in cancer and other organ abnormalities, development, or function. There’re a lot of great opportunities. A great way to start is to volunteer in a lab. BIPN 194 [seminar class taught by Dr. Meharena] is a good place to start too.
SQ: Do you have any comments on this field of research that we haven’t covered so far?
Meharena: I will say that it’s a really exciting field. It has a lot of potential to grow, and with the ability to generate chimeric models we’re overcoming a lot of obstacles that have been limiting us in terms of making progress. I feel there’s going to be significant exciting avenues opening up soon. For that to happen, we need more people to be engaged and participating in research.
References:
https://pubmed.ncbi.nlm.nih.gov/16904174/
https://pubmed.ncbi.nlm.nih.gov/18035408/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963504/
https://pubmed.ncbi.nlm.nih.gov/30545851/
https://www.frontiersin.org/articles/10.3389/fgene.2021.681259/full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3149993/
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