Archive for November, 2008

South Djoum ChimpIf you try to search in the library or over the internet for AIDS, you will find a huge amount of information available. You will also figure out that all scientists reach a dead end at the step of treating or vaccinating against AIDS. Their stop makes you never stop thinking: why can’t they continue? Why is there no cure for such a disease? Or at least why can’t they stop the progress of this illness by simply making a vaccine? It is like reading the same book millions of times without understanding its end, then you re-read the last chapters but still “YOU CAN’T”!!

I think that we need to restart reading the book from its beginning. We need to re-read about the origin of AIDS infections, to know more about HIV genome, and how its genes function; then we may know how to slow down or terminate progression of the virus inside the human body or at least to stop its passage from an individual to another. Hence, we may be able to read the book again and this time we can understand its end.

AIDS was initially reported on June 5th, 1981. But, it is more precise to mention the first documented AIDS case, which was in 1959. At that time, no one was able to define such an illness; however, scientists did a favor for the humankind by preserving the infected tissues till someone would be able to define HIV, i.e. after 1981. I may ask why not before 1959? But who can answer a question like this?

The origin of AIDS has so many controversial theories, including conspiracy theories. One of these is that HIV arose as a result of leakage in the US governmental or military labs during the development of a biological weapon. You may ask Dr. Leonard G. Horowitz (the author of Emerging Viruses: AIDS & Ebola. Nature, Accident or Intentional? And Death in the Air: Globalism, Terrorism and Toxic Warfare) for evidence to prove such an idea. As wikipedia page of ” AIDS origins opposed to scientific consensus” mentions his theory which claims that AIDS virus was engineered by such U.S. Government defense contractors as Litton industries for the purposes of bio-warfare and “population control”.

Dr. Alan Cantwell (the author of AIDS and the Doctors of Death) supported this theory, by naming one scientist that led the US military research on homosexual and bisexual men between 1979 and 1981; he attributed these research activities to Dr. Wolf Szmuness. And, when Dr. Alan was asked about the cases that were reported before 1979, his answer was that the American media masked the truth at that time! This has been also mentioned on “AIDS origins opposed to scientific consensus” Wikipedia webpage.

Another unreliable hypothesis had been advanced by Edward Hooper, as he accused Hilary Koprowski, the polish virologist and immunologist who was preparing polio vaccine using tissue cultures from non-human primates during 1950s, that he might have transferred AIDS from monkeys to human. This idea couldn’t be evidenced when one of these vaccine vials had been checked in 2000 to show negative HIV or SIV (Simian immune-deficiency virus that infects chimpanzees). Also, by checking the protocols of that old research, it is clear they were working on monkeys’ kidney cells that cannot transmit AIDS. But can one negative vial become a prove for the whole negativity?!

The most accepted and recent theory assumes that HIV is an evolution from SIV. This Cameroon Chimpanzees theory was suggested in 2006 after a study on genetic samples from more than 1300 chimpanzees within 7 years by Dr. Beatrice Hahn. It seems that one person had been bitten by one of these apes or got cut while he or she was trying to slaughter one of these animals, maybe for eating purposes!!

If this Chimpanzee in the picture is the main suspect now for HIV triggering on earth, the question now is: Do we have current reports for the same transmission from apes to human? If yes or no, I think we need to re-study and search that SIV which might tell us something about its “daughter” HIV (as accepted by most of the scientists). It is like reading the book from its beginning not the last chapters, sure it will tell us new things.. Like what? I really dont know, it may be like the first idea that led to inventing the nuclear bomb, would you believe me if I told you more than 60 years ago that there is an idea to bombard the nucleus to make a huge bomb? It was just an idea, but the know how was not known. I think it is the same for the AIDS book: we need to re-read but we still don’t know what is going to happen after that reading. All I know that we need to re-read with a new vision, not the same ordinary way of reading.

Image credits: http://upload.wikimedia.org/wikipedia/commons/8/8d/South_Djoum_Chimp.jpg

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Hello, hello. You’re now tuned to your favorite blog: micro-writers.egybio.net. Tonight we have this very special guest, live, online. After two months of waiting, we finally got this exclusive interview with the emerged Streptococcus pyogenes strain, the most dangerous ever, M1T1. We have it here, with us, in the studio.

– Hello, M1T1. Welcome in our studio.Streptococcus pyogenes - Adopt A Microbe
– Hey there.

– We knew from our resources, which are totally classified, that you got yourself in trouble recently.
– (Interrupting), I did NOT get myself in trouble. EID set me up.

– M1T1, Would you please calm down & tell us a little more about yourself?
– Well, I belong to Group A streptococci (GAS) aka Streptococcus pyogenes. M1T1 is my serotype; I’m just a clonal strain. As you know, S. pyogenes colonize human skin & throat causing either non-invasive (sore throat, tonsillitis & impetigo) or invasive (necrotizing fasciitis NF, scarlet fever & streptococcal toxic-shock syndrome STSS) infections. Actually, NF gave me my nick: Flesh-eating bacteria.

– So, you cause all people NF & STSS?
– No, kid. It depends on their genetic susceptibility, what you call “Host–pathogen interactions”. I was isolated from patients with invasive as well as non-invasive infections during 1992–2002. This is NOT entirely my fault; humans can make me extra virulent by selecting the most virulent members.

– Back to your history, when have you exactly been isolated?
– M1 & her sisters were the worst nightmare in US & UK in the 19th century as they caused the famous pandemic of scarlet fever. “Nevertheless”, early 1980s was the golden age of my strain as well as my very close sisters M3T3 & M18. We caused STSS & NF in different parts of the world. Great times, great times!

– Only for you, I suppose! So, what made you hypervirulent? What caused you this “epidemiologic shift”?
– Two reasons Dr Ramy K. Aziz identified that improved my fitness to humans: the new genes I got from phages & “host-imposed pressure”. Both resulted in the selection & survival of me M1T1 the hypervirulent strain. Dr Aziz’s work at Dr Kotb’s lab resulted in identification of a group of genes I got from phages that changed my entire life.

– Interesting! Tell us more about that. How did phages “change your life”?
– Dr Aziz proved that I differ from my ancestral M1 when he found that I have 2 extra prophages (lysogenized phages didn’t get the chance to lyse me, so they became integrated in my genome):
1. SPhinX which carries a gene encodes the potent superantigen SpeA or pyrogenic exotoxin A (scarlet fever toxin).
2. PhiRamid which carries another gene encodes the most potent streptococcal nuclease ever, Sda1.
3. He also found that phages conversion from the lytic state to the lysogenic state resulted in exchange of toxins between our different strains (aka Horizontal Gene Transfer). Phages are very good genetic material transporters, what makes “strains belonging to the same serotype may have different virulence components carried by the same or highly similar phages & those belonging to different serotypes may have identical phage-encoded toxins.” What a quote from Rise and Persistence of Global M1T1 Clone of Streptococcus pyogenes.

– Well, It was not that interesting. So, what? What’s the significance? How that made you hypervirulent?
– You can’t get it? You’re not that smart, are you? Tell me, what made M1 hypervirulent causing scarlet fever in the 1920s and me hypervirulent causing STSS in the 1980s with a 50-years decline period?

– Superantigen?
– Exactly. You do have your moments! Superantigen encoding-gene was present in us and absent in strains isolated in the period between them. The interesting part, for me of course, that humans after 50 years of absence of hypervirulent strains had absolutely no superantigen-neutralizing antibodies. That was the real invasive party. Superantigen causes high inflammatory response because of its non-specific binding to immune system components (antibodies & complements) causing an extremely high inflammatory response. In fact, SuperAg inflammatory response is “host-controlled”.

– So, what about Sda1?
– Streptodornase (streptococcal extracellular nuclease) helps me to degrade neutrophils that entrap me in the neutrophil extracellular traps (NETs). So, I can invade humans freely & efficiently and be able to live in their neutrophils. Dr Aziz proved in his paper “Post-proteomic identification of a novel phage-encoded streptodornase, Sda1, in invasive M1T1 Streptococcus pyogenes” that it’s all about C-terminus in my Sda1; the frame-shift mutation increased my virulence while deletion decreased it.

– Now we know about your SuperAg & nuclease (DNase), what’s the “host-imposed pressure”?
– I have my own SpeB (Protease), I use it to degrade my other proteins (virulence factors), which provides me with a good camouflage & gives me access to blood. When the host immune system recognizes me, it traps me in NETs. At this time, I secret Sda1 to degrade neutrophils. Actually, SpeB protects you, humans, from my Sda1& my other toxins. When SpeB was compared in patients with severe & non-severe strep infections, it was found that SpeB wasn’t expressed in case of severe infection. Expression of SpeB may be host-controlled, as host selects the mutants with a mutation in covS, a part of my regulatory system which regulates my gene expression including SpeB gene.

– Finally, M1T1. How do you see your future?
– More new phage-encoded genes, more selection of the hypervirulent strains by the host & more regulation of expression of my virulence factors. Pretty good future! I also count on humans to not develop immunity against me like what happened in 1980, when I got new virulence factors or allelic variations in my old ones.

Thank you, M1T1. Pleasure talking to you…….M1T1? M1T1, where are you? Why do I feel this strange pain in my throat?

Image credits:
Streptococcus pyogenes: http://adoptamicrobe.blogspot.com/

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Yesterday, I was watching an episode of “The Doctors” where they were talking about a new study that completely amazed me…It was carried out at the Karolinska Institutet & the findings come in favor of men, mostly!! They found a link between a person’s genetic makeup & their relationship status. I have to admit that is pretty interesting.

The gene studied was AVPR1A, which actually has to do with one of the receptors for ADH, predisposes men to make unhealthy decisions, when it comes to relationships, once they have the allele 334. That is how it got its name, which it is pretty much now famous for as “The Commitment Gene”. Presence of two copies makes matter even worse…It is funny once you start thinking hmm..and how did they discover that!! The study was carried out on 550 sets of twins where they had to complete a survey evaluating their life in general & specifically when it comes to relationships..whether they are married, divorced, not ready to commit yet..

Luckily for the ladies, these genes can’t really dictate what a person does because that is all about his choices…but after all, it would be added on to the growing pile of excuses :). I wonder in the future if women would ask their future spouses to first undergo an examination and search for that gene…Who knows what the future might bring us!

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Researchers at Penn state discovered two new proteins which activate cells in the immune system & cause a rare form of blood cancer.
Helper T-cells can stimulate B lymphocytes to produce antibodies against the pathogen. Also, stimulate cytotoxic T-cell that kills infected cells.
Shortly after the elimination of pathogen, most of cytotoxic T-cells die while few of them remain to protect the body from re-infection with the same pathogen.
In some cases of autoimmune diseases these cells don’t die, but they expand & attack many tissues as bones to cause rheumatoid arthritis “RA” or bone marrow to cause leukemia.
Immune Response
Researchers at Penn state tried to find out conditions that cause abnormal expansion of these cells, they made an intricate computer modeling which follows up signals involved in either activation or death of these cells.

The researchers have found two proteins “IL-15 and PDGF” which are needed to cause activation & proliferation of T-cells. IL-15 causes activation, while PDGF stimulates their growth.A macrophage of a mouse stretching its

Another signaling protein called “NFκB” controlled by the two proteins which prevent the death of cancer cells whatever they are over expressed.All those proteins may become targets for drugs; when they blocked NFκB with drugs in cells from leukemia patients, an increase in mortality of abnormal T-cells has been observed.

So, the key is to find out what stimulates T-cells to survive & proliferate.

Source: Science Daily.

Image credits:  Immune response.

 

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