Why does petroleum have a rainbow-like reflection in the sunlight?

When the light strikes a thin film of a fluid(such as petrol) in which light moves slower than air, there is an initial reflection off of the surface. Some of the light is transmitted into the fluid and it reflects off the bottom and then finally travels back out.

These waves take slightly longer to reflect due to the travel of a very short distance through the oil, they are now slightly out of phase with the initial reflection, creating a rainbow of interference

And this phenomenon is known as thin-film interference.

All cats with 3 or more colors are females, why?

Cats may have 3 colors at times, they are also known as Calico cats. Cats who have 3 or more colors are female, in other words male cats cant have more than 2 colors(with an exception, discussed later). So why is that? What is the biological reason for this phenomenon?

Like most of the mammals, cats have a XY sex determination system. So the female cats have two X chromosomes and the male cat has a X and a Y chromosome. The X chromosome is the chromosome which determines the color of the cat. So in females there are two chromosomes, so they can have an orange and a non-orange gene on each of the X chromosome.

But this is not possible in male cats as they have only one X chromosome which will either have a orange and a non-orange gene. However, there is one exception to this case where if a male cat has a genetic disease such as Klinefelter syndrome in which the male cat as an extra X chromosome. Klinefelter syndrome cats have XXY chromosome and can have 3 colors.

Remember rabies virus genes in order

Mnemonic to remember 'Rabies virus' genes and remember the order in which they are translated

Remember it with relation to dog bite; If someone gets a dog bite always tell them:

No ProbleM Good Luck

N - P - M - G - L

N - Nucleoprotein
P - Phosphoprotein
M - Matrix protien
G - Glycoprotein
L - Polymerase

 -IfuM

An autobiography of a Th1 cell about HIV vaccine

 Hi guys, this is an essay on 'HIV Vaccine' which I had to write for an essay writing competition for my college. I got 2nd prize for it.
Have fun reading it.

____________________________________________________


"Hi, I am a Th1 cell, I have just been accepted as a potent cell to fight the immune system in the thymus, my birthplace like all other cells is the bone marrow. I come from the family of the T-helper cells, we are the bosses of all the immune cells as we tell them what to do. We fight the various components that enter the blood which do not belong to us. Such as various bacteria, viruses and proteins etc. One of the most important cells which take care of the bacteria, viruses and proteins are the marcophages and these macrophages once activated by us play a very important role in the immune system. The other cells are B cells, dendritic cells, the PMNs and NK cells which work under us."

"All of us together are very much potent in fighting the immune system and can take care of any 'pathogen'. But there is a very big problem in our whole system as a virus known as the HIV has entered our system. This virus attacks the macrophages and grows inside it and then replicates inside it. But the main target are the CD4 T cells, which are basically us. Now if we get reduced in the system there is no one to actually tell the immune system what to do and there a functional collaspe of the whole immune system. We cannot fight it as they grow inside us and replicate inside us. So there are various ways in which we could be informed about a threat like this, and one of the way is 'vaccination'. A live or dead pathogen or a part of the pathogen is injected in blood or is exposed to the system due to which we know that a pathogen similar to it maybe encountered in future and the cells can be trained and developed accordingly."

"So why was there no vaccine developed for HIV? I asked the other Th cells. And based on the various interactions I can tell you that first and foremost, the vaccine developed against the surface antigen of the HIV can be made. However that is not possible as when the virus is killed the antigenicity of that virus protein is lost. So in other words we cannot train the cells to such a product which has no antigenicity. And the other is live vaccines in which the virus is made weak and then is injected into the blood. But this is not done as the process is very risky and may lead to an infection if that weak virus can still attack the immune system. One of the other factors is the 'latency period'. I had a talk with another th cell and he said that 'the virus stayed inside me for 2 weeks or so and after that it started replicating.' This means that the virus does not infect the cell as it enters, it infact goes into a so called 'latency period'. And this is one of the reasons why the vaccine cannot be made."

"Another reason for not developing a vaccine is that the virus has various types and each type is different from another and due to these serotypes/variants only one vaccine cannot do the complete job, as the cells of the immune system are very specific. I have talked with 'acquired immune cells' which were from an different origin told us that the lab in which they were cultivated, there HIV vaccine trials have been going on. And in most of the parts of the world like South Africa, Malaysia etc there are HIV vaccine trials going on.

"Hope is not lost yet, as various antiretrovirals in combination with the vaccine may serve as a potent immunisation technique one day. One of the very good and potent antiretroviral drug is tenofovir which may be used as an 'antiretroviral gel'. Final conclusions can be made that the vaccine may be made in several years, but till then prevention is the best way to combat AIDS. If there will be no enrty of the virus in the immune system they wont get to us and no infection will take place."

"Vaccine making will take time but as always remember 'prevention is better than cure' and so now gotta go, I got some Mycobacterium cells to take care of"

Copyright  (c) Mufaddal Dewaswala
____________________________________________________

CURE FOR AIDS has NOT been found

Everyone has heard the 'miracle baby' news, in which the child born had AIDS and then after treatment, he was cured.

Its not a cure because the doctors had hit the virus very early and it is certainly not the case in adults. Children born with HIV maybe cured this way, only children.

It is very nice that people are spreading the news like this but they are certainly spreading it the wrong way.
Eg. people are posting statuses on facebook saying that "finally a cure for AIDS has been found". Well that is certainly NOT true and it is misleading to other people especially misleading teenagers to have unprotected sex.

This is an example of a comment I found on facebook which supports my point

 

A picture from a newspaper:

What if the people only read the bold headline which says "Found: A cure for HIV". So it is very important that we do not misconstrue the news here. If someone in your surrounding is in the wrong impression and has received the wrong news, please do give him/her the right information before they do something wrong.

Have fun I have added the like and share buttons so that you can easily share this post on your fb profile.

Information like this is very vital as it may save some peoples lives.

What if someone typed the human genome - facts about human genome

So 2 days back I studying about 'Human genome project' and I learned that the human genome compromised of about 3 billion base pairs.

Hmmm... 3 billion... thats is a really big number. But I never realized that 3 billion was a REALLY big number until my obsessive mind did some maths.

So I thought what if someone typed the whole genome with a speed of 1 base per second? How much time would that take? So I quickly did the math using an internet calculator and I was kind of shocked to see the result...

So I found out that:

"It would take more than 9.5 decades to type the whole human genome if it was typed 1 base/second for 24 hours a day."

95 years... amazing... I will be posting more interesting blogs and facts like these in future soon.

Microbiology helps in fighting toothdecay!

Personal Blog of IfuM

One of my classmates suggested that, "You should try finding out some organisms which degrades the calculus or tartar(white stuff which usually is formed on the teeth.) and later you can extract the enzyme responsible for this degradation and make mouthwash with it." And I said "You cannot cure tooth problems by microbiology, that IMPOSSIBLE!"

I have got teeth problems for a long time. I always used to wonder that whether microorganisms can be used to cure/heal all my teeth problems. Turns out there are ways in which scientists have been trying to achieve it.

What causes tooth decay? Bacteria are present on teeth. These bacteria convert sugar to lactic acid, sugar can be obtained from any source of food which you eat and it sticks/remains on your teeth. The lactic acid produced causes tooth decay.

Streptococcus mutans which is a facultatively anaerobic, Gram-positive coccus-shaped bacteria. It is most commonly found in the human oral cavity and is a significant contributor to tooth decay.

So a group of scientists have engineered a genetically mutated strain of Streptococcus which do not produce lactic acid. But you may think, what about the rest of the normal flora? no worries because this strain also produces antibiotics which kill/inhibit the lactic acid producing bacteria!

Genetically altered strain of S. mutans is also called SMaRT. It is engineered to have an advantage over native S. mutans strains. It produces minute amounts of a lantibiotic that kills off the native strains but leaves the SMaRT strain unharmed.

Dont get to excited though you may not get rid of toothbrush anytime soon (:

Taste of Potassuim cyanide story

 Personal blog of IfuM

A friend told me a funny science related story the other day and so I cross checked it on the internet and I thought "why not blog about it."

The story is kind of funny, it was related to chemistry and so I expect a good REACTION. The story is about the taste of Potassium cyanide.

First let me introduce you to Potassium cyanide(molecular formula - KCN). It is highly toxic and it is a cellular respiration inhibitor. And the main point here is that its lethal dose is 200-300mg, yup!, only 0.3g can kill you!

So the story goes like this - A scientist was almost dying and had got not many days to live. So as a final contribution to science he told that he would taste cyanide and let people know about its taste. So he brought a pen and a paper, tasted cyanide and then he wrote the letter 'S' and he died. He died before he could write more than "S"!

What does the 'S' stand for? Sweet? Salty? Sour? So much for nothing. Wow great story, isn't it? I really dont know if this story is a myth or a super myth. But people have tasted very diluted KCN and they said it tastes bitter and it smells like almonds.

So now you know this kind of thing happened and if you or one of your friends decide to give some contribution to science and taste potassuim cyanide then first write down these on a piece of paper:

• Sweet
• Salty
• Sour
• Something else?

Then after tasting simply tick the appropriate answer :D

Eggs are veg or nonveg - Mystery solved

Personal blog of IfuM

"Chicken eggs are vegetarian!" It is important that we do not misconstrue this thought here.

Educational visits are arranged to teach us many things, but we may learn something different from what was expected. And thats why I say "Never miss an educational visit, no matter how boring it is; because the trip isn't boring, its you who decides how boring it is going to be."

Now coming back to what I was telling you. Chicken eggs are used to cultivate viruses and we learnt this on an educational visit to Bombay Veterinary college. But what I learnt that eggs which we eat do not contain embryo.

Yes its true. After reading and research I found out that chicken can lay eggs with and WITHOUT mating with a rooster. The ones which do not mate produce unfertilized eggs which do not contain embryos.

So what is a vegetarian egg?
The eggs which we eat contain only egg yolk(a part of an egg which feeds the developing embryo) and the egg white(albumin) and no embryo. You are not eating any living thing per se you are eating only the proteins.

At first I used to think that people who say egg is veg are stupid, well they are not. I personally think that egg which we eat is also called 'table egg' which is veg.

We have all had the experience of thoughts or ideas occurring to us spontaneously rather than as a result of conscious deliberation and so with my knowledge I can say that table egg is veg! Give it a thought let me know what you think in the comment section below. Still the debate continues...

LB stands for Lysogeny Broth

Personal blog of IfuM - 6th Oct 2012

So today I kind of felt a 'my life is a lie' kind of situation as I was reading a few articles on phage enrichment. When I was going through these articles I was looking at various compositions for the medium in which the phage had to be enriched.

And I came across the famous 'LB medium', I was taught(and used to believe) that 'LB' stood for "Luria-Bertani" but it is not so.

What does LB stand for according to the internet then? It stands for 'Lysogeny Broth'. As you all know that sources on the internet maybe deceptive so then I read the original paper which was published in 1952 by Bertani G, from which I confirmed that the sources on the internet are right and LB does stand for 'Lysogeny Broth'

In the paper, Bertani mentions that:
"the formula of the LB medium which I had concocted in order to optimize Shigella growth and plaque formation. Its use has since become very popular. The acronym has been variously interpreted, perhaps flatteringly, but incorrectly, as Luria broth, Lennox broth, or Luria-Bertani medium. For the historical record, the abbreviation LB was intended to stand for 'lysogeny broth.' "

So now I am going to spread the news to all of my friends that LB stands for Lysogengy broth. It is quite stupid but also alluring how I(and many others) have studied the wrong thing and didn't even arrive at the right thing for so long.


References: 
Bertani, G. 1952. "Studies on Lysogenesis. I. The mode of phage liberation by lysogenic Escherichia coli." J. Bacteriology, 62:293-300