Sometimes science can be baffling, especially if you are a young scientist trying to make your mark in the community. Take for example – Dr. Wolfe-Simon, at a point in her career where she had pinned every aspect of her future on a discovery that could be groundbreaking nonetheless – the GFAJ-1 strain. This might be old news to some people but most of us might have heard of this strain found and cultured from Mono Lake, CA which was supposedly was be able to utilize arsenic instead of phosphorous to grow. Of course, as you might know – the basic building ‘blocks’ of life per se are – C, H, O, N and P, of which the last one holds a special place when it comes to holding together the segments of a DNA chain. Now phosphorous here holds a special place amidst these other elements of life – not only is it a major player in holding the nucleotide bases together via phosphate bonds, but it also is a major component of signaling mechanisms, on/off switches for genes and metabolic pathways. Of course when someone claims that a life form as familiar as a bacterium can instead utilize As instead to at least – hold DNA together – there will most definitely be more than a set of frowns in the scientific community. This was reinforced by the announcement by NASA in the December of 2010 that they had found a As-based life form and heralding it as one of most important discoveries of all time. Of course, what has followed next, really is what separates science from religion/faith – Science needs corroboration.
What Dr. Wolfe-Simon depicted in her paper in Science (which a number of other scientists have labeled as bad science) is that this “novel” bacterium is being able to survive in very low levels of P and instead in rather high levels of As. They even suggest that the toxic As is being incorporated into its DNA! On the contrary, other studies on GFAJ-1 have shown that – 1. It is able to grow on arsenic containing medium but only if the culture contains enough “contaminating” phosphorous for it to scavenge it out of the medium and 2. The bacteria is not being able to incorporate As into its DNA, as shown by Dr. Redfield and her team at U of British Columbia, Vancouver – using a caesium chloride gradient, they separated the cellular DNA into fractions and subsequent M/S analysis turned out that no As was found in the cells DNA. As of now – two separate studies have shown that, Dr. Wolfe-Simon’s medium did indeed contain enough phosphate ‘contamination’ to support the bacterium’s growth in spite of having As in the medium. Albeit more studies need to be done to confirm that it is so – there is also the case that most time lab conditions and natural habitats are not exactly similar. Nonetheless, NASA’s claims for a novel form of life (read – alien life form) has somewhat been disproven. The journal – Science has released their statement saying that – GFAJ-1 is “a well-adapted extremophile that lives in a high-arsenic environment”. They do not seem to be retracting the study but seem to be pleased to publish more information on GFAJ-1. What’s disappointing is that when bad science gets so much publicity it sometimes is hard to keep your faith in every other scientist. Of course, “popular science journals” and the media/press do play their part in the innumerable misinterpretations as well. Recently – Dr. Wolfe-Simon stated - "As far as we know, all the data in our paper still stand," she wrote in an email. "Yet, it may take some time to accurately establish where the [arsenic] ends up." But read this exercept from her original GFAJ-1 paper
These measurements therefore specifically dem- onstrated that the purified DNA extracted from +As/–P cells contained As. Our NanoSIMS analyses, combined with the evidence for intra- cellular arsenic by ICP-MS and our radiolabeled 73AsO43 – experiments, indicated that intracel- lular AsO43– was incorporated into key biomol- ecules, specifically DNA.
I leave it to you – to make your own conclusions, but a couple of things I believe still stand – 1. GFAJ-1 is an interesting extremophile. 2. Science has its way delving out appropriate corrections.
N.B. – GFAJ-1 is a clever acronym for Give Felisa a Job. :-)
What Dr. Wolfe-Simon depicted in her paper in Science (which a number of other scientists have labeled as bad science) is that this “novel” bacterium is being able to survive in very low levels of P and instead in rather high levels of As. They even suggest that the toxic As is being incorporated into its DNA! On the contrary, other studies on GFAJ-1 have shown that – 1. It is able to grow on arsenic containing medium but only if the culture contains enough “contaminating” phosphorous for it to scavenge it out of the medium and 2. The bacteria is not being able to incorporate As into its DNA, as shown by Dr. Redfield and her team at U of British Columbia, Vancouver – using a caesium chloride gradient, they separated the cellular DNA into fractions and subsequent M/S analysis turned out that no As was found in the cells DNA. As of now – two separate studies have shown that, Dr. Wolfe-Simon’s medium did indeed contain enough phosphate ‘contamination’ to support the bacterium’s growth in spite of having As in the medium. Albeit more studies need to be done to confirm that it is so – there is also the case that most time lab conditions and natural habitats are not exactly similar. Nonetheless, NASA’s claims for a novel form of life (read – alien life form) has somewhat been disproven. The journal – Science has released their statement saying that – GFAJ-1 is “a well-adapted extremophile that lives in a high-arsenic environment”. They do not seem to be retracting the study but seem to be pleased to publish more information on GFAJ-1. What’s disappointing is that when bad science gets so much publicity it sometimes is hard to keep your faith in every other scientist. Of course, “popular science journals” and the media/press do play their part in the innumerable misinterpretations as well. Recently – Dr. Wolfe-Simon stated - "As far as we know, all the data in our paper still stand," she wrote in an email. "Yet, it may take some time to accurately establish where the [arsenic] ends up." But read this exercept from her original GFAJ-1 paper
These measurements therefore specifically dem- onstrated that the purified DNA extracted from +As/–P cells contained As. Our NanoSIMS analyses, combined with the evidence for intra- cellular arsenic by ICP-MS and our radiolabeled 73AsO43 – experiments, indicated that intracel- lular AsO43– was incorporated into key biomol- ecules, specifically DNA.
I leave it to you – to make your own conclusions, but a couple of things I believe still stand – 1. GFAJ-1 is an interesting extremophile. 2. Science has its way delving out appropriate corrections.
N.B. – GFAJ-1 is a clever acronym for Give Felisa a Job. :-)