Science Simplified!

Mar 31, 2014

Mar 24, 2014

Oh Mighty Chondria, who art thou?

2:19 AM Posted by Coffee Table Science , , No comments
A diagram showing a mitochondrion of the eukar...
Mitochondria are organelles surrounded by membranes, distributed in the cytosol of most eukaryotic cells. Its main function is the conversion of potential energy of pyruvate molecules into ATP. (Photo credit: Wikipedia)
The term 'mitochondria' is not alien to many. School level science introduced us to it, where we were told that these thread-granules (literal translation from Greek) were the power houses of the cell. They make energy in the form of ATP (adenosine triphosphate), something that the cells can use and that was all we ever needed to know. But these organelles have their own history and their own secrets that are so grave, that they would even put a Dan Brown novel to shame. Well, let us begin with some history.

Background (we have been outsourcing since the begining of time!!- it seems)

Although, we are very comfortable with the concept of mitochondria supplying power to the cell, many are surprised, when they get to know that the mitochondria were not originally a part of our cells. The popular theory about mitochondria is that its ancestors were probably some bacteria, who were exceptionally good at energy production and somewhere way back in time, our ancestral cells thought that it would be good idea to outsource this mechanical task of energy generation and concentrate on something that required more detailed attention, like cellular maintenance and reproduction. Of course, this would be in return for food and energy for the outsourcing staff and thus, mitochondria were officially accepted within our cell walls. 


So where is the evidence that supports this theory you might ask. Well, there are two strong points favouring this theory. The first being that even within our cells, mitochondria look and function very much like any bacteria, found in nature. The second being that all the energy production that is carried out by the mitochondria occurs as per the instructions dictated by the DNA of mitochondria themselves, a feature not seen with any other organelle in the cell. Thus, even inside our cells, mitochondria enjoy quite an independent life and are not at the mercy of the cell. Rather, recent findings have shown mitochondria to have a more dominant role in the cell, one even involving introduction of bits of its own genome into the cell's nucleus. 

Numts- hijacking the host

Yes, there is sufficient scientific evidence to show that these mitochondria send out to the nucleus, pieces of their own DNA so that it can be integrated into the nuclear DNA of its host cell. The DNA repair mechanism in the nucleus of our cells works like a charm, to incorporate these new bits and pieces of DNA floating inside the nucleus. Called, numts (short for New mitochondrial DNA), these insertions of DNA, occur much more frequently that one would like, leaving many to wonder what mitochondria are actually up to?

The mitochondrial genome is about 14,600 bases long. Interestingly, 90% of this information has already been sent out and incorporated into the human genome. Taking into consideration that the smallest protein coding gene is only 500 bases long, our mitochondria have pushed in a lot of information into our genome already and continue to do so on an everyday basis. 

Numts are not recent and are neither unique to animals

Numts have been inserting themselves into our our genome for quite some time now. A study published in 2007, has shown that 80 % of the numts seen in humans were also seen in chimpanzees at the same location on the genome. Thus, numts have been on their mission, even when chimps and humans had not separated into different species. Also, a similar phenomenon has also been reported in plant genomes, where chloroplast DNA is imprinting its nuclear information onto the host nucleus, while yeasts, honeybees and even rodents have seen numts. 

So far, research has shown that there are at least twelve sites in the human genome that have accepted numts and it is likely that this is just the beginning of the find. Interestingly, most of these sites are active genes suggesting that insertion of numts is largely a targetted exercise and not just a random event. Although, numts insertions stay largely neutral, there are also instances where such insertions can lead to diseases in individuals. Although rare, numts insertions have been established as cause for instances of Plasma Factor VII deficiency, Pallister-Hall Syndrome, Usher Syndrome type IC etc.

So what are Numts upto?

To be honest, nobody really knows why numts exist. There are a few theories though that have been put to explain the behaviour of mitochondria and the existence of numts.

A very plausible explanation is that the presence of numts is part of an extremely long process of integrating the mitochondria into our genomes. Having uploaded its genetic information into the cell's nuclear databank, the mitochondria can continue to carry out their regular function of energy production without having to bother about their own reproduction. In a way, one could also say that mitochondria are outsourcing this function just like they have outsourced production of certain proteins to the cell in the past. Over a period of time (which in this case is a few more million years), mitochondrial DNA will be entirely transferred to the nucleus, mitochondria will become a true cell organelle and its genetic control will be handled by the cell's nucleus, thereby completing the integration.

The other explanation is that numts are mitochondria's way to ensure that its genetic information is safely stored. As power houses of the cell, mitochondria are under severe oxidative stress at all times. As we all know, oxidative stress can severely damage stored genetic information and also obstruct DNA repair mechanisms.With numts, mitochondria are creating a backup of the nuclear information, so that it can be brought back later, when need be. How are mitochondria doing something of this sort, is something we do not really know at this point in time. However, one thing is for sure, these mighty chondria are pulling some extreme feats every single day. 



References:

Hazkani-Covo, E., & Graur, D. (2006). A Comparative Analysis of numt Evolution in Human and Chimpanzee Molecular Biology and Evolution, 24 (1), 13-18 DOI: 10.1093/molbev/msl149

Hazkani-Covo, E., Zeller, R., & Martin, W. (2010). Molecular Poltergeists: Mitochondrial DNA Copies (numts) in Sequenced Nuclear Genomes PLoS Genetics, 6 (2) DOI: 10.1371/journal.pgen.1000834

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Mar 6, 2014

Immortality! - The story of Hydra

1:30 AM Posted by Coffee Table Science , , , , No comments
Immortality - a phenomenon, we admire in characters of fictional books, - the impossible, crazy scientists hope to attain in their labs and the unfulfilled desire of all human kind. We could do a 100,000 things if we were immortal; take up more reading, switch to a better job or simply take more vacation time when needed. Yet the constraint of time pushes us to maximise what we have at hand, make most of resources available and fit in a myriad of things into our timelines to make our lives more 'meaningful'. But what if there was no time constraint. There was no pressure of perishing. There was always ample time to do what we wanted. Well, that's the life of Hydra, the microscopic fresh water creatures that lead an immortal life.


Hydra sp
Hydra
The Hydra are small fresh water animals that are just a few milllimetres long and have a radial symmetry. Although, we have known Hydra since the 18th century, a recent discovery has sparked tremendous interest in these organisms. The paper published by Daniel Martinez in the year 1998 claimed that senescence was absent in Hydra. Now what is senescence you may ask. Senescence is the process of a cell growing old and ultimately dying.  In our youth, we have ample amount of stem cells that can replenish dying cells, but as we age, the number of stem cells in the body start decreasing and the replenishment of dead cells ceases. All living beings undergo this process throughout their life times and ultimately die, due to lack of new cells being generated in the body. Hydra, on the other hand, do not undergo this process at all and therefore, are immortal!

The secret to Hydra's immortality has now been revealed, thanks to the research done at Kiel University. It is called the FoxO gene. Initial reports have been able to show that in the absence of this gene Hydra show signs of aging. Basically, what scientists saw was the decreased number of stem cells in the Hydra when the activity of FoxO gene was obstructed. In Hydra, where the activity of FoxO gene was enhanced, researchers saw a larger number of stem cells available to replenish the old and dying lot. What the team of researchers at Kiel University also saw was the effect the obstruction or enhancement was having on the immune system of the organism.


 So, Hydra are immortal. How does it help us?


Interestingly, the FoxO gene is not something that is unique to Hydra but is also found in humans. Studies have shown that this gene is particularly active in people who live past 100 years. Research done on Hydra has been clear enough to demonstrate that an active FoxO gene means more stem cells that can replenish old and dying cells and saying good bye to senescence. Also, FoXo gene can help one boost his immune system as well.



 So, now that we know what the FoxO gene can do, it is time to let you imagination roll! But before you do that, do not forget to share this post with like-minded people!

ResearchBlogging.org

Martı́nez, D. (1998). Mortality Patterns Suggest Lack of Senescence in Hydra Experimental Gerontology, 33 (3), 217-225 DOI: 10.1016/S0531-5565(97)00113-7

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Mar 4, 2014

A raft like none other!

3:21 AM Posted by Coffee Table Science , , No comments
If you have always gloated about how intelligent humans are, how we have built, boats, houses, smartphones and computers for ourselves and how we have built communities to protect ourselves and to work together, well, you have never seen ants in action then!

If you still do not believe us on this, ask yourself this is,

Would you cross the Amazon with nothing but your large extended family or people in your neighbourhood. 

Well, ants do!

Here, this colony of ants migrate across the Amazon by making a raft out of themselves




Feb 6, 2014

How sexology became a science!

esa-tetra-kama-sutra
(Photo credit: Satyrika)


SEX, something that consumes everyone's existence at a given point in life. It is the key to our existence, and a means to our survival. Sex is as basic as food and water itself. Its safe to say that we as a species are curious about anything related to sex but why was sexology such a late bloomer in science. Lets find out.

Have you heard about Vatsyayana? It wont be surprising if you have never heard that name before. So, let me  ask you this, Have you heard about the Kama Sutra? Yes, very likely you have heard about the book of love making from the exotic land of India. And the man who authored this oldest known manual on sexual practices- well, yes- Vatsyayana.

While we silently thank the Kama Sutra every single time we stumble upon an inevitable bump of lacklustre in our bedrooms, we so often just ignore the great mind that wrote it in the first place. So here is to Vatsyayana, the humble guru, the forgotten sage, who explored the mysterious realms of eroticism and put in plain and simple text so that generations and society could benefit from it.

So why did Vatsyayana write the book in the first place? Story goes that Vatsyayana was compelled to write the manuscript on sex because of a freak love making incident that involved a royalty (King Satakarni) who struck his queen in an act of passion, which lead to her inevitable death. Now to warn people about the dangers and educate them on the behaviour that is expected, out of ones sexual partner, Vatsyayana wrote the Kamasutra. Now that really gets you thinking about ancient India and how 'kinky' was very much the norm then! Your bed buddy dying on you because of some freak accident in the bed room was just run of the mill. (Way to go Kinky Ancient India!) 

So, educating people on sex was Vatsyayana’s motive, and if you do get the opportunity to read the Kama Sutra, you will be pleasantly surprised. Apart from the very hyped and over rated encyclopaedia of sexual positions, the Kama Sutra also has a lot of tips and lessons of how to carry on a proper marriage, which includes trifle things like cleanliness, coping with loneliness and how to punish a cheating husband. But this text, this holy grail, if you like, for the fully functional sexual adult, was only for the benefit of the eastern world, until the late nineteenth century. The first popular translation of the Kama Sutra that took the western world by storm was the one from Sir Richard Francis Burton. Well until then, its safe to assume that the missionary position ruled the world (except for the east of course).

The conservationist society that the western world was back then, the translation from Sir Burton came under
Sir Richard Francis Burton
fire, from the government. But whatever is controversial will spread and so it did. But this article is not so much about the Kama Sutra and sex but about the people who brought sex to the academia and made it a legitimate (non smirking, and non-oohing ahhaing ) serious topic of conversation and also the topic of study.

Similar to the Kama Sutra, manuscripts written by Philaenis (believed to have existed between 3rd-1st century BC), a courtesan living in Greece, carry detailed accounts of her courtship is believed to have heavily influenced the Ars Amatoria written by the famous Roman poet Ovid. While it is ok to credit the Kama Sutra or the Ars Amatoria, as the oldest self-help books to sexual practices, satisfaction and contentment, they are not necessarily, the emergence of a scientific approach and methodology to sex and sexual practices.  

The influence of science on sex and sexual practices was seen much, much later. In fact, the first study and wide scale research done on sex was published in 1837, which involved an in-depth study on 3,558 prostitutes in Paris. Alexander Jean Baptiste Parent-Duchatelet’s work, published posthumously was a compilation of eight years of ardent research, which today, is regarded as the first sex survey that carried sociological weightage.  
After that there were a few men that braved the road between carnal pleasures and science and looked at the whole act with a keen scientific eye. It is these brave men who brought sex to the academic forefront. 

One of those men was Havelock Ellis, the founding father of Sexology, the man who challenged taboos that Victorian society associated with human sexuality. Being sexually vocal, explicit and bold, is considered a little off-putting even in today’s time and age; imagine being someone who just released a book about masturbation and homosexuality (a term he coined). Ellis is known to have uncovered a lot of sexual phenomena, which we consider quite normal today. It is interesting however that despite being termed a 'pioneer in sexology', his personal life, was quite unusual. He was a virgin till 32 and was in an open marriage with a lesbian. Now that’s interesting!

Magnus Hirschfeld is also considered one of the pioneers of Sexology, and is regarded as the first to openly speak about homosexual and transgender rights (transvestite was the term coined by him), and is even called the “Einstein of Sex”. The works of Richard von Krafft-Ebing- in the Psychopathia Sexualis, is also regarded as the foundation of sexology itself. These men pumped in the much needed fuel that propelled the field of Sexology, as we know it today.

Alfred Kinsey
While Ellis, Magnus and Richard may have turned on the heat, in black and white- tight collared west, temperatures of scientific inquiry into everything sexual plummeted down to sub-zero after the Second World War. Taboos got reinstated, even more firmly than before the War, and all the ground breaking progress achieved just decades ago, was facing serious treat. It was not until Alfred Kinsey, a humble America biology Professor, that sex and sexology, got a new wave of academic interest.

Kinsey’s academic interest was gall wasps, but like all unsuspecting biology teachers, he was made to take a class on Sex-Ed at the University of Indiana, the one class that would change his career interest. Soon enough he realised how little was published in the scientific community about normal sexual behaviour and practices. The course soon became one of the most popular courses at the Universityand Kinsey became a Science Rockstar. Alfred Kinsey is credited to bring the scientific inquiry (and interest) back into sex. Kinsey is credited to bust notions like – women don’t masturbate, and answering questions like how many times is normal to masturbate? He is also known for inventing the Kinsey scale – that measures homosexual tendencies of an individual (used even today).

Speaking about sex, carries its own set of awkwardness. It is hard to imagine how these brave men managed to stand on top of their roofs and ask simple questions like – why do we have urges like we do, and what is normal- something that we still can’t get a hang of even today; but whatever we do know today, its thanks to men who were not afraid to ask.
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Jan 15, 2014

Do we really know why cats purr?


Purring in cats is quite common. While you may have seen a domesticated cat at your house or  in the neighbourhood purr, there is documented evidence of even larger cats such as tigers, lions, panthers and cheetahs which have been found purring in the wild. While cat owners often take purring as a good sign and end up lathering the feline with loads of attention and ‘awwwwwws’, the fact remains that no one really knows why cats purr. So, although, the common cat got domesticated into human settlements somewhere around 10,000 years ago, there is very little that we actually know about why they exhibit such behaviour. Modern scientific methods continue to be used to determine, what might seem to a trivial question. But all studies so far have only ended up adding more more speculated reasons as to why cats purr.

Before we tell you to possible reasons for purring of cats, let us look at the question HOW do cats purr? Initially researchers had theorized that cats have a separate organ for purring. But when no such organ was found, an alternate theory emerged that the purr was caused by blood passing through a vein in the abdomen or as a by-product of the sound of blood hitting the aorta artery in the throat of the cat. However, it was only about a decade ago that studies revealed that the purring sound is brought by the combined action of the diaphragmatic and laryngeal muscles, when triggered by intermittent signaling of neural oscillator. Put simply, this means that cat’s brain signals muscles in the voice box to vibrate thereby allowing them to function as valve for air flowing due to the action of the diaphragm, thus producing a purr! The interesting part is that a domesticated cat (and its close relatives) can purr while inhaling as well as when exhaling whereas larger cats such as lions, tigers, panthers etc. purr only when exhaling. Now that we know for sure, how cats manage to purr, we will move onto the reasons they purr.

Firstly, purring in cats is attributed to their way of garnering attention or indicating hunger to their owners. Although, this is a popular theory, it is also more of a ‘cat owner’ explanation and therefore, highly biased. It is likely that cats purr at certain times of the day, which might coincide with their feeding times, making the owner that the cat is hungry. It could also be the case that cats are well aware that their owners give them food when they purr, which also means that we have sufficient evidence that cats (by purring) have devised a mechanism to manipulate actions of their owners to suit their needs. Well, as interesting as this sounds, it does not quite explain why wild cats purr.


Moving onto the second and equally well accepted theory that the purpose of purring is quite versatile and could mean anything from contentment to fear, from pain to anxiety or could just be a way to communicate with its young ones, depending on the situation the cat is in. The theory for purring as a way to demonstrate emotions can explain various scenarios such as a purring during a regular visit to the veterinarian clinic or when that seen when cats are recovering from an injury. A nursing mother may purr near her newborn kittens to establish a bond with them or even instill a sense of security and comfort among her litter.


What if we told you that all it took to heal a broken bone was a lot of talking to yourself or your family. Well, unfortunately we can’t do that but apparently cats can! This interesting theory emerged from a research carried out at the University of California, which emphasized on the self-healing powers of cats. How do they do it? Well, you might be well aware that cats are good at conserving energy, quite evident by their long hours of rest and sleep. But their lack of activity should also mean that they should have reduced bone density. Yet, they don’t.  Studies revealed that the 25 Hz frequency of purring in cats is a good stimulus for bones to regain their integrity or for muscular cells to recover from atrophy, without spending a lot of energy.


Thus, the simply curiosity of why and how cats purr is now leading the way as candidate treatment for spaceflight osteopenia, or the bone loss astronauts face while spending time in conditions of zero gravity.

Contributed by : Sneha Shenoy





Jan 9, 2014

Cure Cancer with TRAIL

Cancer cells are notorious for their ability to detach themselves from tumours, flow through the blood stream and find themselves new sites in the body to adhere to and grow in size and number. Called metastasis, this process allows cancerous cells to not only survive in the body but also regroup at some other site, where you are least suspecting them to be and show up their ugly side as tumours. Site specific radiation therapy or even chemotherapy, for that matter, lacks the specificity to attack cancerous tumour alone, let alone freely floating cells and therefore, in spite of all advances in medicine and all the treatments that are offered to patients, there has never been a 'cure' for cancer. This, however, might soon change. 
Cancerous Cell
In the mid 1990s, researchers Steven Wiley and his team at the Immunex Research and Development Corporation, Washington identified a new protein called TRAIL ( TNF-related apoptosis-inducing Ligand). The TNF family of proteins has been long associated with apoptosis or programmed cell death. Apoptosis is the mechanism by which an organism gets rid of problematic/unnecessary cells (self or foreign) in the body. (Every day, about 50 billion cells undergo apoptosis in an adult body). The TNF family of proteins perform a special function in our body by initiating the same process of apoptosis against tumorous cells, hence the name, Tumour Necrosis Factor. Naturally, TNF superfamily is one of the main ally of researchers world wide, looking into development of anti-cancer treatments. Further research on the TRAIL showed that the protein, secreted by normal cells, is capable specifically binding to cancerous cells on specific sites called the 'death receptors'. Once the TRAIL binds to a cell, it begins a chain reaction that finally results into the death of the cell. 

Many drug companies latched onto TRAIL as the ultimate cure for cancer and initiated studies to test the efficacy of the protein. TRAIL was used in combination with chemotherapy and yet clinical trials conducted gave mixed responses. What was worse was that repeated administration and exposure of TRAIL to tomourous cells, also seemed to confer some resistance to these cells, thereby reducing the efficacy of the drug. Although, there are many mechanisms proposed to explain TRAIL resistance, the fact remains that TRAIL is one of our best chances to check cancerous growth and needs to be administered with much more caution to patients and not be used in excess like antibiotics have been used in recent past.

The team of biomedical scientists in Michael King's lab in the Department of Biomedical Engineering at Cornell University decided to do exactly the same. Rather than bombarding tumours will large amounts of TRAIL, they decided instead to use it to attack the cause of cancer recurrence viz., tumorous cells that float freely in the bloodstream. Called Circulating Tumour Cells or CTCs, these cells use another protein called E-selectin to facilitate their adhesion to endothelial cells in the body and thereby forming new tumours. Luckily, E-selectin is also responsible for attracting leukocytes (white blood cells), our body's defending cells, to sites of injury or inflammation. What the researchers at Cornell managed to achieve was introduce nano particles into the blood stream with TRAIL on them. These nanoparticles were designed in such a way that they would bind to leukocytes after entering the blood stream.

Whenever CTCs attempt to adhere to cells, they need the assistance of E-selectin to complete the process, which will also bring leukocytes into the picture. With TRAIL by their side, these leukocytes can now easily recognize CTCs and flag them for destruction via apoptosis, thereby preventing them from adhering to endothelial cells. Eventually, all CTCs can be identified and destroyed the same way and the individual may indeed become free of cancerous cells. While preliminary studies in mice have shown this method to be extremely effective, there is still a lot more work to be done before this becomes a method to be used routinely. Nevertheless, the cure for cancer may be not that far away.

Sources: 

Mitchell MJ, Wayne E, Rana K, Schaffer CB, & King MR (2014). TRAIL-coated leukocytes that kill cancer cells in the circulation. Proceedings of the National Academy of Sciences of the United States of America PMID: 24395803

Steven R. Wiley, Ken Schooley, Pamela J. Smolak, Wenie S. Din, Chang-Pin Huang, Jillian K. Nicholl, Grant R. Sutherland, Terri Davis Smith, Charles Rauch, Craig A. Smith and Raymond G. Goodwin (1995). Identification and characterization of a new member of the TNF family that induces apoptosis Immunity DOI: 10.1016/1074-7613(95)90057-8

Nov 26, 2013

Beetle Beauty!!

050 Namib Ground Beetle_1
050 Namib Ground Beetle_1 (Photo credit: tok tokkie)
Ever seen a water bottle the size of a beetle? What if, we told you that the bottle fills itself? Sounds like a miracle, doesn't it? The Namib beetle belonging to the Stenocara genus is here to demonstrate this miracle. Found in the world’s oldest desert, the Namib desert, this beetle demonstrates an indigenous method of obtaining water from the arid surroundings.