Scientific Scribbles

The voice of UniMelb Science Communication students

Sea Monkeys- a nostalgic childrens toy with an amazing superpower

I remember my sister and I receiving a packet each and being mesmerised as they grew and reproduced in the little container on top of my bookcase.

Sea-monkeys are a hybrid breed of brine shrimp, that were invented by Harold von Braunhut in 1957. They have been such a big hit they have even had comics and a tv series based on the little alien-like creatures. Even to do this day, with all the technological advancements to toys, they continue to be popular. For those unfamiliar with the product, in a packet you get sachet of brine shrimp eggs, that you simply put into a tank with purified water and watch as they hatch into life.

From when I watched my own when I was a kid, till most recently when I saw them in a toy store- I have always wondered how exactly do they work? How can an animal come alive from a packet of dry eggs?

            Marketing for the pet Sea-Monkeys. Photo credit Roger Johnson via Flikr

Brine shrimp- super human crustaceans

Brine shrimp are an unique creature that have what seem like impossible abilities. You can:

  • Dry them out
  • Dissolve them in alcohol
  • Set them on fire
  • Put them in water that is 50% salt
  • Immerse them in insecticides
  • Boil them at 105°C
  • Chill them to temperatures close to absolute zero (which is the point at which atoms stop moving)
  • Place them in such extreme pH levels that they would normally dissolve human skin.
  • Grow them in the vacuum of space

And they will continue to survive! But how do they do it?

It was actually the long tail of the brine shrimp that led to them being labelled Sea-Monkeys
Photo credit Wikicommons 

Living in a state between life and death

When sea-monkeys face non-favourable conditions that are able to enter a state so that is neither alive nor is it dead. This is known as cryptobiosis, by which all metabolic actions within the organism stop. It can live in this state indefinitely, until environmental conditions are more favourable for it to come out of this state.

Sea monkeys undergo anhydrobiosis- a type of cryptobiosis- where they lose up to 97% of their water content.

When the conditions of the environment are good, the female brine shrimp will produce thin-shelled eggs that can immediately hatch. However, when the conditions are less then favourable, she will produce hard-shelled cysts which contain close to fully-developed larva.

Water is an essential liquid to all life forms- inside our cells it helps keep the molecules moving and mixing- allowing for important chemical reactions to occur. When water is removed from our cells, these important molecules inside lose their structure, so they can no longer function. Brine shrimp have gotten past this by forming a solid matrix made up of the sugar trehalose- which then maintains the structures of the molecules by supporting the proteins and membranes- basically freezing them in place.

The Great Salt Lake of Utah, America- home to the brine shrimp. Photo by Public Domain

An extreme adaptation for an extreme environment 

Brine shrimp have inhabited salty bodies of water worldwide for over 100 million years. These habitats can dry up and disappear for months up to decades, so the shrimp have had to adapt to be able to get past this issue.

Wouldn’t it have been easier to no longer reside in these areas rather than have to develop this extreme adaptation?

These areas of high salinity, also have increased risk of suffocation, as water becomes saltier it can hold less dissolved oxygen. So very few animals can survive in these extremes, therefore there are no predators to the brine shrimp. It’s an interesting adaptation, choosing between living in an environment with such harsh environmental conditions or being preyed upon by other organisms.

So next time you see a packet of sea monkeys at your local toy store or department store, I suggest giving them a go. So you can experience the wonder that are these little fluttery creatures and know exactly how they have been able to hatch from that little packet.

(This post is not sponsored by Sea Monkeys, the author just thinks they are pretty cool!)


A Sunny Public Health Announcement

Every year, hundreds of Australians flock to our beaches during the summer. Image credit Nikita Vasilyev, via Flickr.

It’s almost time to shed those winter gains in preparation for the summer just around the corner. But how much do you care about your exposure to sunlight, what it might be doing to your body and how to better protect yourself? This is a get-to-know guide on what you could be expecting during those hot, summer, beach days.

Beyond the rainbow

The sun shoots out energy in the form of electromagnetic radiation, what we perceive as sunlight when it reaches Earth. Our atmosphere protects us from the more dangerous light such as x-rays and ultraviolet, but it doesn’t do a perfect job. Ultraviolet radiation is invisible to the naked eye, we don’t have the appropriate receptors in our eyes to detect them. It’s beyond visible light and therefore has higher frequency, shorter wavelengths in comparison. This translates to higher energy and a greater potential to cause chemical reactions, which can be a good and a bad thing. All UVR is classified as carcinogenic or cancer causing, because of this property.

We split solar UVR into three categories: UVA, UVB and UVC, ranging from longest to shortest wavelengths. UVC is completely absorbed by the atmosphere and only UVA and UVB reaches the surface. UVA is the closest to visible light and is the least energetic. The more energetic UVB is mostly absorbed by the atmosphere but roughly 10% gets through.

UV-Benefits and UV-Cancerous

Sunlight is great for you, it’s warm and delightful but it also has great physiological benefits too. Vitamin D is essential to all life and is entirely produced by our skin cells when exposed to sunlight, specifically UVB radiation. Deficiency in vitamin D can cause diseases related to bone health such as rickets and osteoporosis.

However, the World Health Organization recommends that only, “5 to 15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high“.

We’re usually exposed to sunlight longer than necessary during summer. We know through sunburns that UVR has enough energy to damage the surface of our skin. However, both UVA and UVB are also classified as carcinogenic, meaning that they can cause reactions in our bodies that lead to cancers. UVB can directly break covalent bonds in our DNA, producing cancer cells that can later develop into tumours or melanoma, the fourth most common cancer in Australia. Although UVA has less energy, it can still damage DNA indirectly by generating reactive species in our cells.

If that’s not enough to scare you, UVR also damages the collagen fibres and degrades vitamin A, which help keep the youthful appearance. Excessive sun exposure has been linked to accelerated aging of the skin. More sun = more wrinkles and sag!

Apply sunscreen 20 minutes before exposure and reapply every 2-4 hours. Image credit JoeBlubaugh, via Flickr.

Sunscreen and protection

Apply sunscreen and reapply! You’re probably annoyed by how much this is thrown around, but sunscreen really is the most effective way of protecting yourself in the sun. We’ve come a long way in the sunscreen industry and there are now hundreds of different options available. Look for sunscreen that is SPF30+ and broad-spectrum. SPF30+ offers the recommended amount of protection from UVB radiation, and broad-spectrum includes UVA protection, which is not rated. If you look at the ingredients, most sunscreens use chemical filters, mineral filters or a mix. Shop around and choose the one that is most comfortable for you. Chemical filters are generally lighter and less greasy but offer less protection than mineral filters.

More tips and tricks

  • Get your mate to help you apply sunscreen – you must apply sunscreen to all exposed areas of your skin, another set of hands can really come in handy!
  • Avoid going out during peak solar hours – the sun is at its highest and sunlight at its strongest from 10 pm – 2 pm.
  • Check the UV index – you can find this information at your local meteorologist; however it’s still recommended to protect yourself every day of the week.
  • Try to wear light layers of clothing and a hat to limit your skin’s exposure. If not, wear sunscreen on all exposed areas of skin.
  • Wear sunglasses – the receptors at the back of your eye are prone to damage caused by sunlight. Protect your vision by wearing sunglasses that filter out UVR.
  • Don’t go tanning – it’s terrible for your health and only works to accelerate the aging of your skin. Use tanning products instead.

Continue reading “A Sunny Public Health Announcement”


Strange Platefellows

Last night, as I scrolled through my favourite (very science-y!) food website in a haze of hunger and procrastination, I came across a recipe for chicken mole poblano. “Chicken, chillies, and… chocolate?” I thought. “Eugh.” Then I caught myself—why was that my immediate reaction? Of course, cultural contexts and personal taste play a significant role in deciding whether things “go together”. But is there any scientific, objective method to determine successful food combinations? What are we missing out on? What does Remy know that we don’t????

Remy from Ratatouille (2007). I can only dream of transcending to his level. From GIPHY

First of all, though: what is flavour? It’s tempting to equate ‘flavour’ with ‘taste’, but taste is limited to what our taste buds perceive. Flavour, on the other hand, describes our entire sensory experience of food, and is comprised of taste and aroma. (If you want extra credit, flavour also factors in a food’s texture and temperature.) Yes, the smell of food plays a huge role in your flavour experiences, which is why everything tastes of nothing when you have the flu.

The smell of food comes mainly from aroma compounds, which are, quite literally, molecules that have an aroma. While all foods contain hundreds of aroma compounds, only a few will be dominant; for example, cocoa has upward of 600 aroma compounds, but only about 80 of those are considered to be the main contributors to cocoa’s flavour.

One hypothesis that has become fashionable in recent times is the idea that the more dominant aroma compounds two foods have in common, the better they’ll taste together. This idea gained some traction among more adventurous chefs and scientists alike, and an article in Nature found that, at least in Western cuisines, there is a significant tendency to combine ingredients with many overlapping aroma compounds.

 

Putting the theory to the test
How well does this idea hold? Consider the humble molecule 4-methylpentanoic acid. With a smell described as “pungent” and “cheesy”, it’s a dominant aroma compound of baked wheat, tomatoes, cheese, basil… does the combination sound familiar? You guessed it, pizza!

When the moon hits your eye like a big pizza pie… that’s 4-methylpentanoic acid! Image by author, modified from Wikimedia Commons

But one anecdote is never enough: If we trawl through whole databases of aroma compounds, are there any innovative, non-intuitive combinations that arise? Enter Heston Blumenthal, a celebrity chef and molecular gastronomist who did much to popularize the flavour-pairing hypothesis. After accidentally landing on a winning combination of white chocolate and caviar (both of which have have high concentrations of trimethylamine), Blumenthal and his friend Francois Benzi hit on the pairing of pork liver and jasmine, both of which contain indole.

The most enjoyable work I came across while researching flavour-pairing came from Khymos, the blog of organometallic chemist and food chemistry enthusiast Martin Lersch. In a column called “They Go Really Well Together”, he invites his readers to share their own kitchen concoctions using hypothetically compatible ingredients. Anyone want to take one for the team and do a taste test of chocolate, coffee, and garlic?

 

Food for thought (couldn’t help myself, folks)
The flavour-pairing hypothesis is not without criticism; and perhaps its most damning flaw of the hypothesis is its most fundamental: if it’s true that the two foods taste better the more their aroma compounds overlap, then it should also be true that the fewer aromatic compounds two foods have in common, the worse they taste together. However, there are no published papers as of right now that systematically test this side of the coin. This is leading many skeptics to believe the theory is no more than a passing fad.

While I am fully in favour of throwing out unworkable theories instead of fudging the numbers, I’ll admit I did love how this little community of food enthusiasts is taking a scientific approach to cooking; along with the curiosity, experimentation, and collaboration among everyone in digging for answers—and really, isn’t that what drives us all to do science?

Now, if you’ll excuse me, I’m headed to the kitchen to make myself a strawberry-cilantro salad—hold the sewing needles, please.

 

Want to play with flavour pairings? Try these sites.

 


Men vs Mice

The latest breakthrough in the field of mammal reproduction hints at a possible future in which men could be deemed obsolete.

At the Chinese Academy of Science, researchers have produced healthy mice pups with two mothers, no males involved.   This new work comes thanks to the amazing combination of stem cells and gene editing.

Unfortunately, when a similar process was attempted with two male mice, the offspring didn’t survive longer than two days.  Does this research endanger the relevance of the entire male sex!

The evil creature threatening the entire male sex. Image credit: Nick Harris (Flickr)

 

Why make mice from same-sex parents anyway?

Now it might seem a weird concept for animals to reproduce without both male and female sexes. However, when it comes to the wonderful diversity of the animal kingdom, there a variety of ways we create the next generation, not all of which require two sexes.

My personal favourite is parthenogenesis, in which the development of the embryo doesn’t require fertilisation. This means they can reproduce all on their own! It isn’t seen often, but has been observed in several species including; lizards, snakes, fish and even birds. Some species have all the options, and can even reproduce by both sexual reproduction and parthenogenesis, such as the ancient Komodo dragon.

The Komodo dragon, capable of reproducing by both sexual reproduction and parthenogenesis. Image credit: Poppet Maulding (Flickr)

However, alternative reproductive methods such as parthenogenesis, are not seen at all in mammal species. This new research aimed to gain insight into what is restricting us to the two-sex approach. So, what was the best way to analyse mammal reproduction? See if we can break it.

 

So, how did they break mammal reproduction?

We have genes which are required for our development into an embryo. Some of these are shut down by ‘imprinting’ genes. Mammals normally require both a mother and a father to stop these ‘imprinting’ genes from interfering. However, if the ‘imprinting’ genes are removed from our DNA then the problem is avoided. Simply put, that’s exactly what the researchers did. Using the forefront of gene editing technology, CRISPR, the researchers deleted the ‘imprinting’ genes.

The team took edited stem cells, specifically haploid stem cells, from one mother, then injected them into an egg cell from another mother. Both the egg and stem cell contain half of the information required for a complete mouse, which made this process possible. Haploid stem cells were used because they naturally contain lower amounts of the problematic ‘imprinting’ genes making the overall process more successful.

The breaking of mammal reproduction was successful. From 210 embryos, 29 produced live mice, each capable of reproducing on their own. For a new practice such as this, 29 is a significant result.

When the researchers used a similar approach with male mice they were not met with such success. No mice pups survived 48 hours after birth.

 

What about us?

This ground-breaking technique has the potential to be used on other mammals, us included. So, one could imagine that one day the male sex would no longer be required for the human race to continue.

My face after realising I might no longer be needed (not actually my face). Image credit: Si Wilson (Flickr)

 

There are also questions to be answered about the morality and method behind editing our own DNA.  We would also seek reassurance that children would have every opportunity of survival and health and wellbeing would not be compromised.

However, assuming all those barriers are passed, there is hope for everyone! The team is aiming to change and improve the process so that the two-male approach could one day also be possible. This would mean couples of all forms could have biological children of their own. At the end of the day men are not going to be obsolete, and everyone wins – a happy ending!

 


Genetics, politics and murders. Who ever thought such a day would come?

Have you been following the American politics lately? Ever heard about the senator Elizabeth Warren?

Wait! Wasn’t this supposed to be about science? How is American politics related to science?

Well, it turns out Elizabeth warren has claimed to have taken a “genetic test”, to prove her origin to be native American.

Is that even possible? Proving your origins through a test?

Yes, in fact mankind has developed ways and means to do so; genetic genealogy.

 

Genealogy? What does that even mean?

Genealogy is derived from the Greek words genea and logos, meaning generation and knowledge. Genealogy is the study of one’s family history or origin; tracing back their lineages.

Family tree. Image from flickr

Genealogists use the genetic makeup to understand lineages.

Genetic genealogy is the practice of using DNA testing to identify one’s ancestry or lineage.

 

Back to the basics

Our DNA is neatly packed in structures called chromosomes. We humans have 23 pairs of chromosomes in total. Of which, 22 pairs which we call the autosomal chromosomes and the 23rd pair, the sex chromosomes. Females have homologous X chromosomes as sex chromosomes, while males have a X and a Y chromosome.

Among the 23 chromosomes one of each pair is derived from both the mother and the father’s chromosomes.

The blame game. Image by Ludie Cochrane from flickr.

In male, the sex chromosome consists of an X and a Y, where X is retrieved from the mother and Y from the father.

In females, sex chromosomes consist of two X chromosomes, each from both the mother and father.

Mitochondrial DNA is another set of DNA present in the power house of the cell. This DNA is inherited exclusively from the mothers and passed down to her child.

 

Depending on the kind of ancestry question raised, Y-DNA test, Mitochondrial DNA test and autosomal DNA genetic genealogical tests can be done.

 

How does genetic genealogy testing work?

The different genetic genealogy testing companies (like 23andme and AncestoryDNA) have a DNA extraction kit which is used to extract DNA sample(like cheek scrapping or chewing gum) from the client who is curious about their origin. They match the DNA to their own repository of DNA samples derived from previous testings.

These companies have their own repository of markers identified from previous tests stored in the database. The companies match the samples or “markers” to their previous data.

Markers are mostly the SNPs (Single Nucleotide polymorphism) found in the DNA. This SNPs might be exclusive for a particular ethnic group which will be helpful in identifying them.

The findings that come out from the testing is more or less provide answer to the question, “in the current scenario where does your DNA come from?”, and not the “past of the DNA itself”.

This being the major drawback of the tests, provides varied results when testing using different providers.

Moreover, we all inherit parts from both our parents. The 23 chromosomal pairs have been received one half from the mother’s  and the other half from the father’s chromosome. During recombination, half of both the maternal and paternal ancestry is inherited, not the complete ancestry.

At the same time, these tests might reveal half the truth about your ancestral origin, but not the entire truth.

There have been many instances of such excruciating scenarios, revealing a part of one’s ancestral origins.

DNA testing botched one’s family heritage.

Curious case of mother and daughter having different ancestry.

 

 

Another pitfall of such test is, it can’t be replicable. That is, every genealogist who test the same sample, have to come out with the exact same inference, which is not the case as of now.

With more inputs to the genealogical databases, eventually the results will be more accurate and replicable more so.

 

Genetic genealogical testing might not seem to be helpful in finding your true origin, it has been perfectly put to use in forensics, solving murders.

Genetic Genealogical testing to solve decade long unsolved murder cases.

 

If you ever want to know more about your ancestry, International society of genetic genealogy wiki is a place to start.


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