Category: Science In Context

Science In Context

Sleep Pattern in Animals

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Sleep that knits up the ravell’d sleave of care,
The death of each day’s life, sore labor’s bath,
Balm of hurt minds, great nature’s second course,
Chief nourisher in life’s feast.

-William Shakespeare, Macbeth

Sleep is a universal phenomenon that takes various forms across the spectrum of life, from the simplest bacteria to the most complex mammals. Yet, the mechanisms and purposes of sleep are as diverse as the organisms themselves. Let’s delve into the intriguing ways different creatures rest and rejuvenate.

Bacteria – do not sleep in the way multicellular organisms do. They may exhibit periods of dormancy or reduced metabolic activity, but this is not considered sleep. Moving up the complexity ladder, plants don’t sleep either. While plants like Mimosa pudica exhibit circadian rhythms, adjusting their movements and metabolic processes in response to the day-night cycle, they do not truly sleep. This concept was demonstrated by de Mairan’s experiments which showed that these plants have quiescent stages during the night.

In a fascinating study in 2020, Kanasa et al. show that Hydra, simple organisms with decentralized nerve nets, exhibit sleep-like states characterized by stillness and reduced responsiveness to stimuli. These behaviours, which follow an ultradian rhythm of about four hours, involve key neurotransmitters like GABA, melatonin, and dopamine, highlighting an ancient sleep mechanism.

Jellyfish, with their primitive neural organization, also exhibit sleep-like states. Caltech researchers observed that jellyfish pulse slowly at night, and disruptions in this pattern lead to sleep deprivation, indicating that even simple organisms may need rest for survival.

Flatworms display nocturnal behaviours likely to avoid predators and optimize feeding. They possess clock genes similar to the TIM gene in other organisms and exhibit a restful, motionless stage without the same need for sleep seen in more complex animals.

Snails exhibit unique sleep patterns, often entering a state known as aestivation and hibernation, closing their shells with a structure called the operculum. Research by Kengo et al. (2024) show that sleep-like states in snails aid memory consolidation, demonstrating that sleep serves critical functions even in these simple creatures.

Pacific Ocean oysters, despite lacking eyes, exhibit disrupted circadian rhythms under artificial light, affecting their clock genes. This highlights the impact of environmental cues on sleep-like behaviours in marine life.

Octopuses show sleep stages (Quiescent sleep and Active sleep) akin to humans, including periods of colour changes and skin patterning, suggesting possible dreaming. These behaviours, influenced by neuropeptide signalling and melatonin production, indicate complex sleep patterns.

Ants follow a strict circadian rhythm, taking short naps totalling about 4 hours and 48 minutes of sleep per day. Soldier ants, however, can sleep deeply for more than 8 hours, showing variability in sleep needs within a species. Fruit flies and cockroaches sleep in such a way that their antenna becomes immobile, and interestingly, they sleep like they are glued to the surface.

Birds have adapted their sleep for flight and survival. Alpine swifts and frigate birds use unihemispheric sleep while in flight, alternating between short bursts of sleep and wakefulness, while penguins sleep using both unihemispheric and bihemispheric slow-wave sleep, adapting to extreme cold by tucking their heads. Looking at the parrots huddling together, the right and left ones are unlucky, because they don’t sleep with their both brains shut. If they receive any signals like a predation attack, they make the in-between birds to alert and fly off.

Marine mammals such as Fur Seals sleep with one hemisphere of their brain, one part of the body becomes inactive and swims over the ocean with only one flipper. While elephant seals exhibit deep NREM sleep underwater with both hemispheres shut. They sleep in such a way and enter into different sleep stages as depicted in the picture.

Thus, we can see that the need for rest and sleep transcends the complexity of the organism, showcasing an incredible array of adaptations and behaviours. From the simplest bacteria to the most complex mammals, each organism has evolved unique mechanisms to balance activity and rest, ensuring survival and functionality in their respective environments. Sleep, in its myriad forms, remains one of nature’s most fascinating and essential phenomena.
Robinson Mohanraj Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

How a lawyer lost the case to a tree

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In 1993, in a murder trial in Arizona, a lawyer had an interesting remark- he said that he is probably the only lawyer to have lost the case to a tree!

Let us hear that story…

In 1992, on the outskirts of Phoenix, Arizona, a woman was found murdered. There was hardly any evidence left by the murderer. However, there is no such thing as a perfect crime. Read on to find out how forensic analysis led to justice.

At the crime scene, forensic investigators found a syringe, some pieces of clothing and a pager that did not belong to the victim (It’s an old case. Pagers were a thing back then, fellow millennials). Homicide detective Charlie Norton noticed fresh abrasion on a Palo verde tree at the crime spot, and took some bean pods off that particular tree.

A fingerprint search helped identify the victim as Denise Johnson. Denise was a single mother of two and lived in ‘the projects’.

The pager was traced to a truck driver Mark Bogan. When confronted, Bogan said that Denise had requested him for a ride and then tried to steal some things from him when he dropped her. He said that he took his wallet back from her but later noticed that his pager was missing.

Scratches on Bogan’s face did not escape the investigator’s eyes while they were interrogating him. However, no traces of blood or skin cells were found under Denise’s nails. Her autopsy revealed that she had died from ‘asphyxiation due to strangulation’.

When the investigator’s visited Bogan’s truck, there was no evidence to suggest that he was involved in the crime- no fingerprints, blood, or hair. However, in the back of the truck they found two bean pods from a Palo verde tree.

The only way to prove that Bogan was at the crime scene, was to prove that the pods in his truck came from that same tree. And that was tough, because obviously, there is not just one such tree there! Arizona has thousands of Palo verde trees.

Now, DNA forensics involving animals and humans is common place. But plants? Not at all. In 1980, Dr Alec Jeffreys developed the technique called genetic fingerprinting that was used as evidence to solve cases, but plant DNA analysis had never been admitted as evidence before.

This is where Dr Timothy Helentjaris came into the picture. A professor at the University of Arizona, Dr Timothy specialized in plant genetics. Since no one had extensively studied Palo verde trees before, Restriction Fragment Length Polymorphism (RFLP)- a DNA analysis technique used frequently for human DNA, could not be performed. Moreover, not enough DNA could be extracted. Hence Dr Helentjaris used the Randomly Amplified Polymorphic DNA (RAPD) technique which works despite low DNA concentration, on any biological sample.

In RAPD, the seeds are removed from the pods and ground to a fine powder. The DNA sample being too low to be analysed needs to be amplified by Polymerase Chain Reaction (PCR) which multiplies the DNA millions of times within a few hours. That sample is then run on an agarose electrophoresis gel and the gel is exposed to UV light to enable visualisation of DNA as short, horizontal bands. The band pattern for every individual is unique. This is the equivalent of a QR code, called a genetic fingerprint.

Dr Helentjaris found that the DNA band pattern of seeds from both pods in the truck, matched each other.  Furthermore, they also matched the DNA band pattern of the seeds from the pods that detective Norton had taken from the tree at the crime scene! When a similar analysis was carried out with DNA from other seed pods in the neighbourhood, there was no perfect match, proving their hunch right- about the pods in Bogan’s truck belonging to the tree at the crime scene.

The judge permitted the results of this DNA analysis to be submitted as evidence. Something that was unprecedented. The jury agreed that this piece of evidence wasn’t circumstantial and found Mark Bogan guilty of first degree murder, sentencing him to 25 year imprisonment.

And thus, despite having no obvious evidence of the victim, Bogan’s lawyer lost his case to the unique seed pods of the Palo verde tree!
Avani Jha Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Entering the cerebral world – learnings from inherent human cells and microbes!

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Neurological disease is the second leading cause of death and disability worldwide. The increasing global burden of brain diseases such as stroke, Alzheimer’s and multiple sclerosis, implies the need for better therapeutic strategies in the management of the disease pathology. To date, delivery of therapeutic molecules and drugs across the blood-brain barrier (BBB) – the barrier that separates the brain from the rest of the body- remains a challenge. In this article, we will understand the different ways in which this barrier can be crossed if a substance has to enter the cerebral world, especially for therapeutic purposes.

Though the concept of BBB was discovered back in the 19th century by Paul Ehrlich, the understanding of it is still evolving. Initially, the blood-brain barrier was simply considered to be comprised of tight junctions of cells which could not be penetrated.  Later studies revealed that there may actually be transporters or gatekeepers, that decide the entry and exit of substances into the brain. 

However, we also know that despite the tight regulation of transport into the cerebral world, certain bacteria, viruses and fungi can pass through and cause infection. Some examples include- Meningitis, encephalitis and viral-induced glioblastoma.

A common mode of entry for the microbes is mediated by specialized gatekeepers of the BBB known as receptors. Mimicking these interactions, researchers have tried to develop nano-carriers coated with microbes to send therapeutic molecules across the BBB in order to help in their targeted slow release in different regions of the brain. This approach has been successful and efficient to some extent, however, the approach fails especially in case of Alzheimer’s or stroke, where the integrity of BBB itself is affected and therefore the release of therapeutic molecules can become unspecific.

Nevertheless, leaving the microbes aside for a while, have you ever wondered how our inherent blood cells themselves cross the blood-brain barrier? Could it be possible to mimic their process for drug delivery?

The answer is yes! 

Several drug delivery studies have focused on mimicking the entry of blood cells into the brain. In the case of the treatment of brain tumours, for example, the nano-carriers use receptors that are inherently used by the blood cells to deliver therapeutic molecules such as neurotoxins. Such a targeted delivery to the tumor regions reduces the off-target effects of the neurotoxin, killing only the tumor cells.

Now, one may also ask whether the Blood-brain barrier only plays the role of a gatekeeper, or does it have other roles as well?

Further studies on BBB unravel that there is a tight interaction between the different cells of the brain, called neovascular units. pericytes, astrocytes, glial and endothelial cells making a neovascular unit. These neo-vascular units of BBB serve as a junction to relay and transmit important signals to the brain. Thus, the dynamic nature of these barriers opens up new avenues for therapeutic intervention in neurological disorders. Several neurological disorders occur due to the dysfunction of BBB, hence repair and the delivery of therapeutics to the BBB itself could become a therapeutic solution. For example, in diseases like multiple sclerosis, the integrity of the BBB needs to decrease in order to prevent inflammation and curb the disease. Thus, BBB holds a vital role in maintaining the physiology of the brain, beyond being just a ‘barrier’ or a ‘gatekeeper’.

Despite the numerous advancements in the understanding of BBB, the efficiency of drug delivery remains undermined due to the difficulty in modelling the multidimensional structures of BBB. Hence further development of efficient models with recent understandings of BBB structure is required to improve targeted drug treatments for neurological disorders.
Keerthana B Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

A revisit to the 2022 Nobel Prize in physiology/medicine

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The 2022 Nobel prize in Physiology or Medicine was awarded to Swedish geneticist Svante Pääbo- for his discoveries regarding the genomes of extinct hominins and human evolution.

Using modern DNA technologies, Pääbo was able to sequence the Neanderthal genome and discovered traces of their DNA in present-day humans. He believes that a transfer of genetic material could have happened when the Neanderthals and Homo sapiens coexisted in Eurasia, following the migration out of Africa around 70,000 years ago.

The presence of such ancient genes in modern-day humans is not only important from an evolutionary perspective, but may also have physiological relevance. Pääbo believes that it may have impacted and influenced the survival strategies in Homo sapiens. For example, the survival of Tibetans at high altitudes and discrete immune responses to infections could be a result of this transfer of genetic material.
Guneet Kaur Author

Disclaimer: The content of this infographic is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Role of gut-brain axis in the feeling of satiety

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It is a common knowledge that our brain influences each and every organ of our body, including our gut, but how strong is this connection? Also, is this connection between gut and brain, a unidirectional one or does the gut also have an influence on ‘the Master’-our brain?

The answers for these questions first came to light when a group of scientists conducted an experiment on two mice. One had all its gut microbiota removed while the other’s wasn’t. On keeping them in stress-inducing conditions, it was noted that the former one showed a greater response to stress. This and many other studies have shown that 50% of Dopamine- the pleasure inducing hormone and about 90% of Serotonin- the happiness hormone, are produced in our gut alone by the microbiota present in the gut.

The fact that our gut produces a variety of neurotransmitters and has more nerve endings than our spinal cord is more than enough to establish the exemplary control it has on our mental state.  No wonder then, that one feels depressed or anxious when one has indigestion. The connection that exists between our gut, its microbiota and the brain is mediated through Gut-Brain axis – have a look at some of the previous articles related to this topic here.

Our gut is lined throughout by glands that secrete a diversity of enzymes. One such hormone is Cholecystokinin (henceforth referred to as-CCK) which is released from our gut after we have a meal. While this hormone is mainly released to digest the fat and protein components in our food, it also makes sure that the stomach is kept relatively ‘full’ after a meal.

CCK does this by initiating a feedback loop through our gut, which sends a signal to the brain to stop eating food. Interestingly, this entire signaling is mediated with the help of receptors, which are present not only in our gut, but throughout the gut-brain axis as well as in the brain. Through this signal, an activation of the vagal afferent pathway takes place- this is the pathway in our body that integrates all the collected information from different organs in the hypothalamus region of the brain and results in modulating our eating behaviour.

Now you know how you get the feeling of ‘satiety’ after eating a full meal!

Now the next question that one could ask is- does the gut microbiome have any role to play in the production of this particular hormone? Well, not much has been explored regarding this topic… but with the way science is catching up, we may soon begin to understand their involvement better!
Malavika V Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Know all about Prosopagnosia: an inability to recognize faces

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Don’t we all recognize people by their faces almost effortlessly? Don’t we search for familiar faces in a party to help blend into the crowd and socialise further? Well rest assured, you are not alone!

But, what if I told you that it is impossible for few people to do what we often take for granted as a simple task. Scary isn’t it? A neurological disorder called prosopagnosia robs people of this ability. Simply put- prosopagnosia stands for face blindness. The mind of a prosopagnosic person denies having seen a face before, even if it belongs to someone known and this has nothing to do with memory loss. When visualizing a conversation that they had with someone, they are able to recall everything about that instance but their face!

There are two major types of this disorder- acquired and developmental.

Acquired prosopagnosia could be because of a brain injury or any other neurological disorder such as trauma, stroke, tumors etc.

Developmental prosopagnosia, on the other hand might occur during the developmental stages of life and in some cases, could also have genetic origins. 

Now, let us dive a little deeper into what this condition is all about. In order to do that, we need to get an insight on how our brain is able to recognise faces in the first place.

Bruce and Young, two scientists, came up with a cognitive model in order to understand the steps involved in face recognition:

  1. Face encoding: In the first step, the structural information about the face is encoded.
  2. Face recognition: In the second step, the structural information is matched to “face recognition units”, which are the stores of face memories in the brain, that determine whether a face has been seen before.
  3. Person identification: In the third step, any familiarity that is recognized in ‘Face recognition’ step, activates a ‘person identity node’, ie. an area of the brain that gives access to the biographical information of the person to whom the face belongs.
  4. Name generation: In the last step, the brain processes or attaches a name to the face, depending upon the first three steps. 

The entire process involves a core network and an extended network- broadly speaking, steps 1 and 2 belong to the core network, while the steps 3 and 4 belong to the extended network. Lesions/injuries in certain parts of any one of these networks can lead to different variants of prosopagnosia. Owing to this, there are two variants of prosopagnosia, especially in acquired prosopagnosia:

Apperceptive: a person is unable to recognize/encode the structural information of the face at all, due to an injury in the core network 

Associative: a person can encode the face but is unable to associate it with any previous familiarity, due to an injury in the extended network.

In the case of developmental prosopagnosia, no obvious structural lesions are found in either of the networks, however certain abnormalities may be seen in the cortex of the brain itself.

One question in the field of prosopagnosia is whether the patients fail in the recognition of faces only or does this inability extend to other areas as well- which in turn leads us to speculate whether the mechanism to recognize faces is involved in the recognition of objects or is it just “face specific”. As per neuroimaging studies, it has been shown that the cortical network of regions involved in face recognition does partially overlap with those of object recognition but it is still distinct. With that being said, some prosopagnosic patients may or may not have difficulty recognizing objects. Even though words are processed on the left and faces are processed on the right, it has been shown that a bilateral network in both cases does overlap. Again, most patients with acquired prosopagnosia have no problem with word processing while some do. However, people with prosopagnosia are thought to have superior voice recognition due to years of relying on voice cues to recognize others. 

Adults and children with this disorder can have other significant implications like traumatic social experiences, chronic anxiety, embarrassment and guilt and usually have a limited social circle because of this inability. Imagine never feeling comfortable around anyone and always having to do ‘small talk’, even with your best friend, because you don’t remember them!

The treatments for improving prosopagnosia differ, depending on the type of prosopagnosia, the variant and intensity of injury at the affected parts. For the acquired variant, most of the training programs usually focus on enhancing coping strategies to deal with poor face recognition. In the case of developmental prosopagnosia, another approach needs to be implemented depending upon the severity.

Nonetheless, counselling sessions for someone who is prosopagnosic or who may have prosopagnosia should be a must as the mental stress associated with this condition can be both overwhelming and confusing. Furthermore, awareness regarding prosopagnosia needs to be increased in order to separate this condition from a simple memory loss. Diagnosis is needed to first rule out the other defects. 

When I personally try to view the world through the eyes of someone with prosopagnosia, I imagine walking down a busy street among a thousand faceless people who either remove their hats to greet me or are gesturing to hit me with it, I have no clue since I can’t understand their facial expressions. This seems extremely scary, confusing and moreover, lonely. I sincerely hope this condition is brought to the notice of more and more people and its treatment can be a bit more definite.
Sanjhi Sardana Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Biosensors: a revolution in the healthcare sector

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Prognosis and diagnosis of any disease as well as its subsequent management has become quite easy now, with the advent in bioinstrumentation, more specifically with biosensors. Just as environmentalists can predict the level of pollution by analyzing the population of butterflies or the color of moths, a ‘biosensor’ is a device that detects our body’s physiological activity to send signals and analyze health-related conditions for diagnosis and/or subsequent treatment.

Everyone is rushing around in today’s fast world, and as a result of this daily pace, diseases are also becoming more prevalent. The lack of clinical resources has led to significant demand for wearable and portable healthcare devices as a potential solution.

Biosensors have become extremely popular today because they support the method of non-invasive monitoring – that is, a monitoring procedure that does not involve any surgical intervention in the body (Read more about the basics of biosensors).

These wearable sensors can be in the form of smartwatches, smart shoes, contact lenses, earpieces, and mouthpieces depending on the location of the body. The technology provides a wireless mechanism that makes it easier for patients to use. Skin is the outermost layer of our body and along with the protection, it also provides a lot of information about the physiological activity of the body through sweat and wound exudates. With the help of wristbands, patches, and smartwatches, the important details in case of hyperglycemia or hypertension can be measured to get instant treatment. Contact lenses can give information about changes in pH levels of the tears. Mouthpieces can be used to detect the rate of saliva production, which is known to be altered in response to exercise, stress, and dietary intake.

Today it might be difficult for people living in remote locations to have close access to any health center but devices such as these would help them get one step closer towards early detection and treatment.

Indeed, when it comes to biosensors, the future is already here. 
Nashrah Mubeen Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Diving into the world of Probiotics

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‘Probiotics’ has become quite a buzz-word nowadays, especially in context of treating any kind of stomach/intestinal disorders. In this article, let us dive deeper into what they really are, and how they work.

Simply put- probiotics are a group of living microorganisms cultured in a laboratory setting to be used as a food supplement for human use. Before you begin to cringe, let us understand that these tiny organisms from the probiotics, that include bacteria and/or yeasts are actually very similar to the naturally residing microbes found in our body and more specifically, out gut. Thus, when probiotics are taken through diet, they add on to the ‘good microbe’ population in our gut.

(Read more about the gut microbiome and its influence on human physiology in the previous articles).

However, as we all know, every microbe consumed might not necessarily be beneficial to our body. And therefore, for a microbe to be called a ‘probiotic’, it must have certain characteristics-

  1. It should belong to one of the species of microbes that is isolated from humans and is easily cultivated in a lab setting
  2. It should be able to survive and thrive in the intestines after being consumed
  3. Last but not the least, it should be safe to consume

So, how to probiotics really work?

Imagine a scenario where the ‘bad bacteria’ in your gut have taken over the good ones. This is a common plot which plays out when one falls sick and the doctor has to prescribe antibiotics to fight off the infection. Now, while the antibiotics kill off all the ‘bad bacteria’ in your body, they may also accidentally end up destroying the ‘good bacteria’, since the good ones are now so few in number. In this scenario, not only is your digestion affected, but the other physiological parameters may also get disturbed.

This is one of the main reasons that your doctor prescribes probiotics along with antibiotics, in order to maintain a healthy composition of gut microbiome and to keep it neutral. Apart from carrying the microbes themselves, probiotic supplements influence the growth and development of ‘good’ microbiota by modulating the components released by the intestinal cells, thus creating a conducive atmosphere for the microbes to grow.

Now, because of their beneficial effect on our bodies, researchers have been trying to find out how the consumption of adequate probiotics can help fight against various gut-related medical conditions. A few conditions that might be helped by adding probiotics to our diet are inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), constipation, lactose intolerance, and antibiotic-associated diarrhoea. Studies have shown that apart from an improvement of the conditions themselves, there is also an enhancement of the working of the immune system by consumption of probiotics.

Considering the continuous bi-directional communication between the gut and the brain, it is not hard to predict that consumption of probiotics can influence our mental health in a positive manner. A few studies indicate the benefits of consuming probiotics or as they are called “psychobiotics” as future possibilities in the treatment of depression and anxiety. Psychobiotics are a sub-class of probiotics mainly containing specific families of bacteria, such as Lactobacilli, Bifidobacteria, Streptococci and Escherichia. Their presence in the gut influences the crosstalk between the brain and gastrointestinal system through the neurochemicals produced by the flourishing microbiota of the gut. Thus, psychobiotics have applications in mood and stress alleviation and even have remedial effects in the treatment of various neurodevelopment and neurodegenerative disorders.

While all this sounds interesting, one may ask themselves the very valid question- what are some easy-to-acquire sources of probiotics?

For a food item to be considered a probiotic, it should contain sufficient living bacteria (preferably in millions) that survive the food processing and the bacterial species present in the food item should have benefits to human health (such as Lactobacillus and Bifidobacterium). Thus, the largest source of probiotics are fermented dairy products, such as yoghurt, kimchi and sauerkraut. Apart from this, probiotic supplements can also be consumed through food, drinks or in the form of capsules or powders. Probiotic supplements are often consumed in combination with prebiotics – which are complex carbohydrates that feed the microbes in our gut. A combination of both means that not only are you supplying your gut with ‘good microbes’ but also providing the microbes with nutritious food so that it can thrive in your gut.

Now you know how to answer most of your stomach distress calls: just call upon your doctor and ask if you can have some probiotics!
Guneet Kaur Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Influence of gut microbiome on Serotonin

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Have you ever wondered why you always have a bad mood when something is wrong with your stomach? Well, recent research has thrown light upon the fact that all our body parts are largely affected by the ‘Gut Microbiome’- a haven of around 300 billion micro-organisms! These tiny creatures are known to play an important role in human development, right from the fetal stage. No wonder our gut is called the second brain

Although microbial colonization in the gut is a successive process, it is known to remain stable and resilient if there is an absence of stress-causing factors. Several factors are known to influence microbial composition at different stages of life- exercise, use of medication, diet and lifestyle.

Out of all the various body systems affected by our gut microbiota, the central nervous system stands out as the most interesting and hot research topic of this decade. Our gut and brain are connected via a bidirectional communication network called the Gut-Brain Axis.

Recent research has shown that our gut microbiome can alter the levels of Serotonin in our body, thus leading to episodes of anxiety, depression, panic attacks etc. And while this word has become common vocabulary nowadays, let us have a closer look at what exactly is serotonin. Serotonin is a neurotransmitter- which means that it carries messages between nerve cells in the brain and other parts of your body. Serotonin plays several roles in the body, including influencing learning, memory, happiness as well as regulating body temperature, sleep, sexual behavior and hunger.

Interestingly, about 90% of the Serotonin found in the body is produced in your gut itself! This serotonin is then released into the blood circulation and transported to other organs. Only about 10% is produced in the brain. Thus, you can now see how relevant and necessary it is to maintain the population of the gut microbiota producing serotonin.

Microbiome dysbiosis or in simpler words, the prevalence of bad bacteria over good ones, is associated with many diseases that lead to altered levels of serotonin. When researchers tried to replace the good bacteria in the gut with bacteria that led to swelling and inflammation, they observed that there was a slowing down of the serotonin secretion!

However, the good news is that you can take care of your gut microbial population, by choosing the right kind of diet. Recent research has also come to the conclusion that intake of probiotics will improve the integrity of the gut lining and help in increasing serotonin production. With a 10.7% of the world population suffering from depression, Alzheimer’s and other mental disorders, probiotics is a ray of hope-towards a world free of anti-depressants and its side effects. Want to avoid such disorders in the future? Make your diet rich in Lactobacillus helveticus and Bifidobacterium longumin from now on and keep your natural serotonin levels at par!
Malavika V Writer

Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.

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Science In Context

Changes in gut microbiome & its impact on mental health

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When one hears the term superorganisms”, the first thing that comes to mind is the Marvel Cinematic Universe Superheroes. But, did you know- that you yourself are a superorganism? Turns out, it’s not a necessity to get bitten by a radioactive spider to become a superorganism. Every human being is home to billions of microorganisms including bacteria, fungi, viruses, and many others which either live on or inside the human body. The number of microbiota present in human beings is almost 10 times the total number of human cells!

The most significant population of microorganisms, which make up to 1 kg, inhabit the digestive tract and they are collectively called the “gut microbiota” or the “gut microbiome”. The gut microbiota is actively involved in maintaining human physiology and communicates regularly with other body organs, including our brain.

A two-way communication system exists between the gut and the brain known as the gut-brain axis. There are two main pathways through which this bi-directional communication system operates:

  1. Neurologic pathway: The enteric nervous system (ENS), present in the intestine (also called the second brain), together with the Vagus nerve make up the neurologic pathway. Various neurotransmitters (GABA, serotonin, melatonin, histamine etc.) responsible for sending direct signals to the brain are produced by the sensory nerves present in the ENS.
  2. Metabolic pathway: The gut microbiota produce several components known as metabolites which have the ability to cross the blood-brain barrier and can affect the functioning of a special type of brain cells known as microglial cells which are necessary for the proper development of the brain as well as for modulation in the behavior in humans.

We have already touched upon these pathways in our previous article.

However, did you know that the population demographics of the gut microbiota changes rapidly with changes in the external environment? In this case- the gut or the digestive system.

For example, production of biologically active molecules such as peptides, or production of inflammatory molecules such as cytokines in the gut, directly affect the gut microbiota population. 

Now that we have had a quick look at how the gut and the brain communicate and what may cause disruptions in this communication (long distance is hard, phew!), we can move on to read about the various ways by which the microbiota residing in us impact our brain activities.

It has been found through various experiments that an imbalance in the gut microbiota (known as dysbiosis), can lead to clinical depression. Long-term swelling (also known as chronic inflammation) that occurs during stress-related disorders leads to changes in gut microbiota reduces serotonin production. The gut is responsible for providing 95% of the total serotonin which is known to play a beneficial role in several functions of the body. Inflammation in the gut can also cause stressful environments for the microbial population and can subsequently lead to symptoms of anxiety and depression.

On the other hand, changes in the gut microbiota can also be caused by on-going stress in an individual. In response to these changes, several metabolites, toxins, and neurohormones are released that can further impact an individual’s mood and eating behavior. The changes in eating behavior can further affect the gut microbiota population, creating a vicious cycle.

Therefore, it is evident that adapting a diet and lifestyle that promotes the growth of beneficial gut microbiota will lead to an optimal utilization of the gut-brain connection and help us maintain good mental health.

Probiotics such as yogurt, cheese, pickles, etc., are found to have species of microorganisms called – Lactobacillus and Bifidobacterium which are key components of a ‘healthy’ gut microbiota. A term called psychobiotic has been recently coined to show their importance in mental disorder therapies as they can act as  antidepressants and work against anxiety. Conversely, high-fat diets and highly-refined carbohydrate diets constitute an unhealthy diet that causes an unfavorable changes in the gut microbiota population and thereby can also affect our overall mental health.

Thus, one can safely say that the way to a ‘happy mind and heart’ is through a ‘happy gut’.
Sanjhi Sardana Writer

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