Science As We Know It

On 16 September 2021, the first human spaceflight with an entirely civilian crew, Inspiration4, was launched into low Earth orbit from the Kennedy Space Center. The mission ended three days later, on 18 September 2021, giving the crew a chance to experience similar conditions to those on the International Space Station (ISS). This included exposure to ionising radiation, living in a vacuum and the challenges of a closed, hostile environment, along with isolation and limited Earth resources. However, it also presented scientists with a remarkable opportunity to conduct research on the biological and behavioral responses of non-professional astronauts during the early phases of spaceflight. The ambitious goal was to gather biological and cognitive data to create a comprehensive database that could inform future crew selection and mission planning.

At this point, you might wonder why we do not possess this data, given that we have been sending people to space since the early 1960s. The truth is, while we have a wealth of knowledge regarding the effects of living in space on the human body, much of this information comes from studies involving professional astronauts – individuals who have been rigorously selected and trained for years to cope with the unique challenges of space travel. If you are curious about life in space, the fearless Mary Roach (https://www.goodreads.com/book/show/9542311-packing-for-mars) answers all the questions you have ever wanted to ask but might have been to shy or embarrassed to say out loud. Wondering how to handle basic (and maybe not-so-basic) physiological needs in microgravity? You will find your answers there. Trust me, once you read it, you will be ready to start saving for a ticket on one of those zero-gravity commercial flights, just for the experience. It is highly recommended for everyone, especially aerospace enthusiasts.

With the advent of space tourism in 2001, our focus shifted towards civilians. Although the sample size was very small—only four crew members—this group was already well-gender balanced, comprising two females and two males. They were equipped with novel flight technologies, such as handheld ultrasound imaging devices and Apple Watches (yes, you read that correctly!). While the original article does not specify whether the crew members were allowed to keep their watches after the spaceflight study, they also employed new protocols for analysing gene and protein expression, as well as cellular and immune system function.

As expected, the three-day stay in the void induced a broad spectrum of physiological and stress responses, evident in changes to gene and protein expression and immune system function, alongside space motion sickness. Notably, cognitive ability remained largely unaffected. Interestingly, most examined factors did not differ from the pre-flight state upon their return to Earth, leading scientists to conclude that a short-term stay in space does not pose any major health risks. What is even more intriguing – yet perhaps expected – is the reported increase in happiness and decrease in boredom among the civilian astronauts during their flight compared to their pre-flight state.

Given the small sample size, all the collected data are very preliminary. However, as more civilians venture into space, we will gather additional insights into the physiological and cognitive responses of non-professional astronauts to life in space. Fingers crossed for all future space tourists! Let’s hope that one day, some of us will have the extraordinary opportunity to witness 16 sunsets and sunrises in a single Earth day while floating among the stars.

References:

1. Jones, C.W., Overbey, E.G., Lacombe, J., Ecker, A.J., Meydan, C., Ryon, K., Tierney, B., Damle, N., MacKay, M., Afshin, E.E., et al. (2024). Molecular and physiological changes in the SpaceX Inspiration4 civilian crew. Nature 632, 1155-1164. 10.1038/s41586-024-07648-x.

2. Overbey, E.G., Kim, J., Tierney, B.T., Park, J., Houerbi, N., Lucaci, A.G., Garcia Medina, S., Damle, N., Najjar, D., Grigorev, K., et al. (2024). The Space Omics and Medical Atlas (SOMA) and international astronaut biobank. Nature 632, 1145-1154. 10.1038/s41586-024-07639-y.

It’s been almost a year since we (re)launched Science as We Know It. Our first post was a small imagination exercise where we pretended a cell was a city and drew some metaphors about what each cell organelle might be comparable to. You can (re)read all about it here.

At the time, some additional interesting parallels were worth exploring. However, in the interest of length, we kept them archived… Until now.

Welcome to What If a Cell Was a City #2 – Energy and Trash. This sounds exactly like the title of a movie sequel, doesn’t it? Well, movie sequels tend to be worse than the originals. So, let’s see how this one goes.

Mitochondria – The Powerhouse Of The Cell

We are aware that calling the mitochondria the powerhouse of the cell is such a cliché. But, given that this comparison is used so many times, do people actually know why it is so?

To produce energy we need to eat food. Us, other animals and even smaller organisms. But the energy that exists in food cannot be used directly by our bodies. Proteins, fats, carbohydrates… All these nutrients come down to one single type of energy, a kind of energy “currency” called ATP: adenosine triphosphate (bless you).

The “industrial” process that takes place in the mitochondria can be resumed relatively simply: glucose (from food) + oxygen (that we breathe in) = carbon dioxide, water (that we breathe out) and energy (in the form of ATP).

ATP is then, just like electricity produced in a city’s power plant, used throughout the cell for any activities. 

Muscle cells need to move? ->  ATP!

Heart needs to beat? -> ATP!

Sperm cells need to wave their little tails to swim until the egg? -> ATP!

Chloroplast – The Greenhouse

If the mitochondria are the pollutant coal power plant, the chloroplast is the environmentally friendly renewable energy power plant, with (almost) zero carbon footprint. However, it does not exist in every cell. Animals, for instance, are not lucky enough to have one. Mostly plants and algae do.

The chloroplast is the place where photosynthesis happens. It is green because of chlorophyll, the pigment that is key to “absorb” the energy from the sun which is then used to make “food”.

The energy coming from sunlight is converted into energy (yes, our boy ATP!) which is then, together with captured carbon dioxide, turned into carbohydrates and oxygen. That’s the reason why plants are so important: they release oxygen and produce carbohydrates!

And, if you ever worried about your diet, you are probably aware that carbohydrates mean sugars. And if you ever have breathed in your life, you are aware that oxygen is good. Food and oxygen! Plants produce food and oxygen!

Too bad chloroplasts only exist in plant cells and algae, though. If we had them, we wouldn’t have to worry so much about actually eating. On the other hand, it is quite sad… Don’t you think plants are missing out on such amazing things as steak… Tropical fruits… Chocolate…?

Lysosome – Recycling Centers

A side effect of the industry and activity in any city is, of course, trash production. Whatever things we use and stuff we do, there will always be waste materials that we need to get rid off. And the same happens inside our cells.

Lysosomes are vesicles that incorporate complex molecules that are not needed in our cells. Inside lysosomes, the pH is low (so it is acidic) which helps with, together with other enzymes, the degradation of the molecules inside. Similar to what happens in the stomach, these contents are degraded inside this kind of waste-disposal center. 

And then, since our cells run on a sustainable economy, many of the products resulting from this digestion are brought back to the cell to be used to synthesize other components. Our cells might be a confusing city, but they for sure are environmentally friendly.

And here it is, after having a look at how the industry of protein production happens in our cells last year, we showed you today how our cells produce energy and recycle waste materials. 

If I were you, I’d stick around for one more year. Who knows what metaphors we will think about next year!

Those trying to conceive are often aware of the importance of a healthy lifestyle for the quality of their reproductive cells and, ultimately, the health of their future children. However, a future father’s diet, in particular, can have a significant impact. Recent research has shown that what prospective fathers eat can influence RNA (ribonucleic acid) in their sperm cells, potentially affecting embryo development and increasing the risk of metabolic diseases that their children may develop later in life.

Let’s take a few steps back. DNA (deoxyribonucleic acid) is the hereditary material in nearly all organisms, including humans. While nuclear DNA is inherited from both parents, the DNA found in organelles called mitochondria is exclusively inherited from mothers. Maintaining the integrity of genetic information is crucial, and this is where various types of RNA come into play. RNA has several functions, including carrying genetic information from DNA to proteins and regulating gene expression. Although RNA is not inherited like DNA, it can still transmit information and influence how a new organism develops.

In both mice and humans, spermatogenesis is a two-step process. First, sperm is produced in the testes, and then it travels to an elongated organ called the epididymis, where it matures. Scientists have discovered that feeding mice a high-fat diet makes the sperm cells in the epididymis particularly sensitive to these dietary changes. While they did not observe any effects on sperm development or reproductive fitness, they did find that male offspring of these mice had increased glucose intolerance compared to those of control mice. Interestingly, when the mice were returned to a regular diet for a period long enough to allow the development of new sperm cells, the negative effects were fully reversible.

The sensors of the high-fat diet are a type of RNA called small non-coding RNA (sncRNAs) encoded by mitochondrial genome. These RNAs are delivered from the sperm to the egg during fertilization and may regulate genes involved in mitochondrial energy metabolism. This makes them a potential candidate for predicting how a father’s lifestyle may affect the metabolic health of his children.

So, future dads, it does matter what you eat—for your health and your sons’. Think twice before taking that next bite of deep-fried food. The good news is that for those willing to change their eating habits, the negative effects of poor diet on their offsprings’ health can be reversed.

References:

Tomar, A., Gomez-Velazquez, M., Gerlini, R., Comas-Armangue, G., Makharadze, L., Kolbe, T., Boersma, A., Dahlhoff, M., Burgstaller, J.P., Lassi, M., et al. (2024). Epigenetic inheritance of diet-induced and sperm-borne mitochondrial RNAs. Nature 630, 720-727. 10.1038/s41586-024-07472-3.

Today’s post is gonna have a sweet flavor. Because 103 years ago, on July 27th, a huge step in the treatment of diabetes was taken: the discovery of insulin. Using insulin is part of the daily life of many people who suffer from diabetes. But what really is insulin? And how does it play such an important role in treating diabetes?

Diabetes has been a known disease for thousands of years. It is known to be related to elevated levels of sugar in the blood. Historically, it has been documented as “honey urine” (a weird combination of words, I know). Diabetes patients’ urine was known to attract ants, due to their increased sugar levels.

Until not very long ago, the only way to deal with it involved changes in diet: reducing the consumption of sugars and carbohydrates. But, in 1921, Canadian scientists Frederick Banting and Charles Best discovered that insulin injections treated diabetes symptoms.

This discovery was so successful that, the year after, a 14-year-old boy became the first person to be treated for diabetes with insulin injection.

But what really is insulin and how is it related to diabetes?

So, let’s start from the beginning: When we eat or drink, glucose is absorbed into the bloodstream during digestion. However, for it to be used to produce energy, it needs to go into our cells, so that they can process it.

Insulin is a hormone that, under normal conditions, is produced in the pancreas. Its role is to precisely regulate glucose (sugar) levels in the blood, by mediating its intake into the cells. 

It acts as a kind of switch that allows the transporters that exist on the surface of our cells to open and allow glucose to move inside.

Without insulin, however, glucose will be floating around in the blood, never reaching our cells because its “doors” will never open.

In cases like this, when the pancreas does not produce enough insulin (or, in some other cases, the body is not able to successfully use the insulin), we have a case of diabetes.

Some of the biggest issues regarding diabetes have to do with the elevated levels of glucose in the blood. This accumulated build-up of sugar, over time, may lead to serious damage in the kidneys, the nerves (which can lead to typical diabetes problems in the feet), the eyes, in the heart… which can ultimately result in death.

And this is why the injection of insulin is so important in diabetes. In the absence of our own insulin produced by our pancreas, the injection of external insulin (which has had different origins: from isolation from other animals’ pancreas to mass production by bacteria) bypasses that problem, therefore opening the glucose transporters on the surface of our cells, allowing the sugar in our blood to reach its due destination and not stay around causing life-threatening troubles.

It is however important to mention that, although it can have genetic origins, diabetes can be prevented by practicing exercise, maintaining a good diet, and having a healthy lifestyle. You can extend your knowledge and read more about diabetes here.

Dear reader, I will ask you for a moment of reflection: Have you ever had one of these moments of stress that you just wanted to release a very loud “AHHHHHH…” or one of those that you are crying all the water you have available in your body and suddenly someone or something makes you laugh?

While I hope this is not the case right now and you are not putting all your hopes on me to make you giggle, I want you to think how you felt after that laugh? Probably better, like a sudden medicine to your pain had been administered.

Well, that is because laughing is a very good medicine and yesterday, 5^th May, was the International Day of Laugh, made to remember that sometimes the only thing we need to calm down our minds is not a 30-minute speech, nor a chocolate or buckets of ice cream, much less a pill, but surprisingly, just a good genuine laugh.

But why does this happen?

Although the reason for this relief can come in multiple ways, including at the psychological level, let’s go deep on what happens in our bodies and brain (despite the importance of psychology, I am still a biologist, so I will avoid a tough adventure in the lands of Sigmund Freud).

To answer this biological question, several studies have been done, mainly by showing the study participants videos with humour content followed by blood sampling or PET*. Yes, you can contribute to science while watching YouTube videos of mischievous cats and dramatic huskies, or while scrolling Instagram watching reels of Italians reacting to people breaking spaghetti.

These studies showed that at a biological level, laughter decreases the levels of DOPAC, which is a molecule present in the blood and that results from the destruction of dopamine (a very important molecule for our brains to feel pleasure and motivation). Therefore, the low levels of DOPAC indicate that dopamine is not being destroyed as before laughing, and we can store it in our brains, making us feel good.  

Additionally, cortisol was also reduced. This is a hormone released during physiological stress (including some diseases) and psychological stress and has multiple effects on our bodies, including the way we process sugars and accumulate fat (unfortunately I couldn’t find evidence that laughter makes us slimmer).

Lastly, laughter triggers a higher release of endogenous opioids (yes, our bodies can produce opioids). If you are asking, the reason why they are called opioids is because they activate the same type of receptors (other molecules usually present at the cell surface that can trigger multiple responses inside the cell) as opium. These can include the now famous endorphins (also released after practising sports) which are molecules mainly produced in our brains but have functions in our entire body, including slowing our respiratory rate and digestive system, explaining why we feel our bodies calming down after laughing.

Chemical mechanisms happening before and after laugh in the brain.

Though these biological changes can explain why laughing is sometimes indeed the best remedy, a lot of research is still needed to completely unveil the biological effects of laughing, which can be depended on the type of laugh (spontaneous laughter, conversational laughter, inducible laugh- the one you get after some beers and everything is funny etc…).

While more efforts are being made to understand whether laughter can be used as therapy not only for mental disorders but physiological diseases, one thing we know for sure: laughter is an excellent communication tool to integrate us within society and makes us more relaxed and happier.

So, my dear reader, whether you are a fellow scientist whose experiment has just failed, a parent of a stubborn child or pet that does not follow your rules, a broken heart soul or if life is just not being easy, go ahead and surround yourself with people that will make you laugh. 

Happy International Laugh Day!

PET: Medical imaging technology that allows to detect and locate certain molecules, such as dopamine or others, in organs.

References:

1. Lee S. Berk et al. The American Journal of the Medical Sciences,1989
2. Sandra Manninen et al., The Journal of Neurosciences, 2017
3. Caroline Kaercher Kramer et al., Plos One, 2023

Cover art by Inês Caiado, inspired by an image generated using Microsoft Bing Image Creator, powered by DALL-E

Last week, on the 25^th of April, the commemoration of the DNA Day took place. Celebrated on this day, the date when, in 1953, Rosalind Franklin, James Watson, Francis Crick, Maurice Wilkins, and their collaborators published their studies about the structure of – you guessed it – DNA.

In line with this, and given that we previously talked about the different structures found in a cell, we thought it would be a great opportunity to talk more about this amazing molecule containing pretty much all our information. (Yes, even more than your Instagram page.)

DNA stands for DeoxyriboNucleic Acid (bless you!), and it is famously shaped like a double helix of two strands that revolve around each other. Within this twisted ladder-like structure, you can find the information for the functioning, development, and reproduction of every known live organism.

“How so?” you ask.

Well, if you think that the four letters that form life are L, I, F, and E, you are mistaken. They are actually A, T, G, and C. And no, I am not having a stroke. Here’s the thing, these long strands of the DNA molecule (a polymer) are composed of smaller pieces (monomers). These smaller molecules are called nucleotides, and there are four of them: adenine [A], thymine [T], guanine [G], and cytosine [C]. 

The sequence of these nucleotides is in itself a real code for the production of proteins, the biomolecules that constitute pretty much everything in a cell. So, each sequence of 3 nucleotides means a specific part of a protein, called an aminoacid: ATT means one aminoacid, GAC means another, and so on… You basically have a library of all the proteins your cells can produce being encoded in this 4-letter alphabet!

Thanks to its double-helix coil shape, it can turn around and around on itself so it can take up the least amount of space possible. To give you an idea, if we completely stretched out the DNA of one single individual human cell, it would measure approximately 2 meters. But the nucleus of the cell, where it is contained, only measures about 6 micrometers in diameter. (If you think Marie Kondo was the master of space optimization and organization, think twice!)

The smart thing about it is that the important parts of the long DNA molecule are specifically uncoiled, according to the needs. If a region of DNA is needed to be “read” for a specific protein, it unfolds and opens up that area in particular. And then it “closes again” when not needed anymore. These very long fibers of DNA, when condensed and packaged, form the chromosomes. Which, precisely when they are so packed, can be easily visualized under a light microscope. 

DNA is not only very efficient for information storing but also for information proliferation. When preparing for cell division, the entirety of DNA is replicated: the helix shape uncoils, both strands separate and new nucleotide building blocks come to “copy” each one of the strands, generating two. These will then form two sets of chromosomes, which can be split between the two new cells that form after division.

And here it is. Now you know why the forensics TV shows enjoy DNA so much. It is a biological trace that is different for every human that exists or ever existed. And all of this is encoded in only 4 letters.

So, hopefully, this article made you think twice before committing a crime.

Happy DNA day!