18 posts · 6,812 views
An Oxford graduate student by day and a scientific activist by night, Nick Anthis isn't letting his Ph.D. research in protein structure get in the way of defending scientific and social progress.
The Scientific Activist
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- November 12, 2009
- 07:39 AM
- 192 views
On Mimicking Phosphotyrosine
by Nick Anthis in The Scientific Activist
When doing science, there's generally one totally optimal way of performing an experiment. But, there may also be several other less optimal means of gathering similar data, and one of those may be much more feasible than the totally optimal method. As a scientist, you have to determine whether this other method is sufficient, or whether it's necessary to expend the extra effort and/or resources on the more difficult method. Sometimes it's totally fine to take the simpler approach (and this will spare some of your precious time and your lab's precious funding), but this post is about a case where it's not.
My colleagues and I have a new paper in JBC (the Journal of Biological Chemistry) that went online late last month. Although I think that the science is pretty interesting, I'm not going to write at length about it here. Instead, you should check out my post about an earlier paper on this subject (integrin phosphorylation) here. Superficially, the two are reasonably similar (at least on the level that I would discuss things on the blog). In fact, much of the newly published work was was actually conducted around the same time as the earlier work (a few years ago), but for a variety of reasons we didn't publish it then. The new paper marks a major advancement of that work, and the new biological data from Jake Haling (in Mark Ginsberg's lab at UCSD) also increases its depth considerably.
However, what I want to write about here is how one goes about studying tyrosine phosphorylation. Tyrosine is one of the 20 amino acids that form the building blocks of the proteins in our bodies. Proteins are often modified after they are produced in the body, and one type of modification is phosphorylation (the addition of a phosphate group to the -OH group of serine, threonine, or tyrosine, i.e. changing -OH to -PO42-). This modification is catalyzed by a type of enzyme called a kinase, and phosphorylation is a type of "posttranslational modification" because it occurs after the mRNA has been translated into a chain of amino acids (i.e. a protein). Read the rest of this post... | Read the comments on this post...... Read more »
Anthis, N., Haling, J., Oxley, C., Memo, M., Wegener, K., Lim, C., Ginsberg, M., & Campbell, I. (2009) integrin tyrosine phosphorylation is a conserved mechanism for regulating talin-induced integrin activation. Journal of Biological Chemistry. DOI: 10.1074/jbc.M109.061275
- October 20, 2009
- 08:39 AM
- 208 views
Two New Papers on Integrin Activation
by Nick Anthis in The Scientific Activist
Just as I was in the process of finishing my doctorate in August, I found out that my first first-author paper had been accepted for publication by The EMBO Journal. This was good news, because we were reporting some pretty fundamental findings in a relatively saturated field, and one of our competitors had managed to successfully stall the acceptance of this paper since March. Up until that point, witnessing this happen firsthand had been a somewhat frustrating and disillusioning experience for a young scientist, but I think that we were vindicated in the end. Anyway, this paper--and another paper that I contributed to--were published online earlier this month.
These studies both explore the important biological process of integrin activation. The first paper (Anthis et al.) provides some new basic molecular details for how this process is carried out in the cell. Cells in humans and other higher organisms exist in a dynamic environment, alternately grasping and disengaging from the three-dimensional web of their surroundings (i.e. the extracellular matrix). Many of these tasks involve a family of proteins called integrins, which act as the "hands" of the cell. The cell internally controls whether an integrin is adhesive by signals from within the cell, using another protein called talin. By exploring the detailed three-dimensional structure of a talin/integrin complex, we showed how key interactions between talin, the integrin, and the inner surface of the cell membrane can elegantly promote the structural changes outside the cell that modulate adhesion strength.
The following figure (from my thesis) illustrates the process of integrin activation: Read the rest of this post... | Read the comments on this post...... Read more »
Anthis NJ, Wegener KL, Ye F, Kim C, Goult BT, Lowe ED, Vakonakis I, Bate N, Critchley DR, Ginsberg MH.... (2009) The structure of an integrin/talin complex reveals the basis of inside-out signal transduction. The EMBO journal. PMID: 19798053
Goult BT, Bouaouina M, Harburger DS, Bate N, Patel B, Anthis NJ, Campbell ID, Calderwood DA, Barsukov IL, Roberts GC.... (2009) The Structure of the N-Terminus of Kindlin-1: A Domain Important for alphaIIbbeta3 Integrin Activation. Journal of molecular biology. PMID: 19804783
- October 20, 2009
- 12:46 AM
- 209 views
New Interactive 3D Molecular Images in Scientific Articles
by Nick Anthis in The Scientific Activist
Late last week, I received emails from two journals (The Journal of Biological Chemistry (JBC) and PLoS ONE) indicating that they are now incorporating interactive 3D images of molecular structures in their papers. The atomic coordinates of all published biomolecular structures have been available for some time at the Protein Data Bank. However, making sense of something as complex as a protein structure can require quite a bit of analysis. So, scientists go through great pains to represent important features of their structures in 2D images for publication. Ostensibly, this new functionality will save readers time and enhance their understanding by letting them explore these structures, but starting with the important features already highlighted.
After a quick look at these new interactive 3D images, though, I have to admit that I'm finding the experience slightly cumbersome. Still, this is a good idea, and I imagine that the experience will be improved over time. You can check out the first JBC paper incorporating the interactive images here, and a collection of papers in PLos ONE incorporating the images here. Below is the press release on the subject from PLoS ONE: Read the rest of this post... | Read the comments on this post...... Read more »
Kumar, P., Vahedi-Faridi, A., Saenger, W., Merino, E., Lopez de Castro, J., Uchanska-Ziegler, B., & Ziegler, A. (2009) Structural Basis for T Cell Alloreactivity among Three HLA-B14 and HLA-B27 Antigens. Journal of Biological Chemistry, 284(43), 29784-29797. DOI: 10.1074/jbc.M109.038497
Raush, E., Totrov, M., Marsden, B., & Abagyan, R. (2009) A New Method for Publishing Three-Dimensional Content. PLoS ONE, 4(10). DOI: 10.1371/journal.pone.0007394
- May 1, 2009
- 07:49 AM
- 399 views
Why Swine Flu Is Resistant to Adamantane Drugs
by Nick Anthis in The Scientific Activist
On Wednesday, the CDC reported that influenza A H1N1 viruses from 13 patients with confirmed diagnoses of swine flu had been tested for resistance to a variety of antiviral drugs. The good news was that all of the isolates were susceptible to the antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza). However, all 13 were resistant to adamantane-based drugs (amantadine and rimantadine). Resistance to adamantane drugs (which were developed first) has actually become quite widespread among flu viruses in general, so oseltamivir and zanamivir are commonly the drugs of choice.
The reason for the difference is that the adamantane drugs target different viral proteins from oseltamivir and zanamivir. The two major proteins on the surface of the influenza virus are hemagglutinin (the "H" in H1N1) and neuraminidase (the "N"). Due to the evolution of the influenza virus over time, these proteins come in a variety of different forms, and we label strains of flu by the specific class of hemagglutinin and neuraminidase the virus carries (H1N1, H3N2, etc.). These are the largest proteins on the surface of the virus, and they are the ones that our immune system generally reacts to. However, they aren't the only ones.
The surface of the influenza virus also has a much smaller protein called M2, which acts as a channel to let hydrogen ions pass across the virus' outer membrane. M2 plays an important role in viral function (more on that below), and, not surprisingly, so do hemagglutinin and neuraminidase. Specifically, hemagglutinin allows the virus to attach to a cell in order to infect it, and after the virus has replicated within the cell, neuraminidase allows the daughter viruses to detach from that cell and infect other cells. For a more in depth description of these proteins, check out this post at Effect Measure.
Getting back to antiviral drugs, oseltamivir and zanamivir work by inhibiting neuraminidase (for details, once again check out the above post at Effect Measure or this more recent one). The adamantane-based drugs, however, target M2. In January 2008, two research groups independently published atomic-resolution structures of the M2 channel bound to an inhibitor. Using NMR, Jason Schnell (in James Chou's lab at Harvard) solved the structure of rimantadine bound to M2 (shown above with the drug in red). Alternatively, Amanda L. Stouffer (in William DeGrado's lab in Pennsylvania) used x-ray crystallography to solve the structure of amantadine bound to M2. Read the rest of this post... | Read the comments on this post...... Read more »
Schnell, J., & Chou, J. (2008) Structure and mechanism of the M2 proton channel of influenza A virus. Nature, 451(7178), 591-595. DOI: 10.1038/nature06531
Pielak, R., Schnell, J., & Chou, J. (2009) Mechanism of drug inhibition and drug resistance of influenza A M2 channel. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0902548106
Stouffer, A., Acharya, R., Salom, D., Levine, A., Di Costanzo, L., Soto, C., Tereshko, V., Nanda, V., Stayrook, S., & DeGrado, W. (2008) Structural basis for the function and inhibition of an influenza virus proton channel. Nature, 451(7178), 596-599. DOI: 10.1038/nature06528
Stouffer, A., Ma, C., Cristian, L., Ohigashi, Y., Lamb, R., Lear, J., Pinto, L., & DeGrado, W. (2008) The Interplay of Functional Tuning, Drug Resistance, and Thermodynamic Stability in the Evolution of the M2 Proton Channel from the Influenza A Virus. Structure, 16(7), 1067-1076. DOI: 10.1016/j.str.2008.04.011
- April 11, 2009
- 02:12 PM
- 455 views
Download Counts Predict Future Impact of Scientific Papers
by Nick Anthis in The Scientific Activist
The gold standard for measuring the impact of a scientific paper is counting the number of other papers that cite that paper. However, due to the drawn-out nature of the scientific publication process, there is a lag of at least a year or so after a paper is published before citations to it even begin to appear in the literature, and at least a few years are generally needed to get an accurate measure of how heavily cited an article will actually be. It's reasonable to ask, then, if there exists a mechanism to judge the impact of a paper much earlier in its lifetime.
Several analyses now indicate that how frequently a paper is downloaded soon after publication predicts--to an extent--how highly it will be cited later on. The most recent analysis (Watson, 2009) compared download counts with citations for the Journal of Vision. There is a lot of extraneous, or at least uninteresting, information in this paper (i.e. that total number of citations correlate with total paper downloads over the lifetime of a paper and that both numbers increase year after year), but the key data is in Figure 6. This figure shows that the number of downloads per day over the first 1,000 days after publication correlates well with the number of citations per year five years down the line (r = 0.62). Read the rest of this post... | Read the comments on this post...... Read more »
Brody, T., Harnad, S., & Carr, L. (2006) Earlier Web usage statistics as predictors of later citation impact. Journal of the American Society for Information Science and Technology, 57(8), 1060-1072. DOI: 10.1002/asi.20373
(none). (2008) Deciphering citation statistics. Nature Neuroscience, 11(6), 619-619. DOI: 10.1038/nn0608-619
Perneger, T. (2004) Relation between online "hit counts" and subsequent citations: prospective study of research papers in the BMJ. BMJ, 329(7465), 546-547. DOI: 10.1136/bmj.329.7465.546
Watson, A. (2009) Comparing citations and downloads for individual articles. Journal of Vision, 9(4), 1-4. DOI: 10.1167/9.4.i
- April 2, 2009
- 07:01 AM
- 397 views
THC Gives Cancer Cells the Munchies Too
by Nick Anthis in The Scientific Activist
Through the results of widespread experimentation of the... well... let's say "non-scientific" variety, it's pretty well known that marijuana has the side effect of making the user very hungry. This is one of the many physiological effects of the active ingredient THC (Δ9-tetrahydrocannabinol). More relevantly, however, THC and other cannabinoids are actively being investigated for various useful clinical purposes, including the treatment of cancer through the inhibition of tumor growth.
A new study by Salazar et al. in The Journal of Clinical Investigation demonstrates that THC causes tumor cells to begin to degrade themselves from the inside (a process called autophagy, i.e. "self-eating"). Although autophagy has been shown to promote cell survival in some cases and cell death in others, the authors show that in this case it causes cancer cells to undergo programmed cell death (apoptosis). Thus, THC activates a series of events within cancer cells, inhibiting tumor growth. Read the rest of this post... | Read the comments on this post...... Read more »
Salazar, M., Carracedo, A., Salanueva, I., Hernández-Tiedra, S., Lorente, M., Egia, A., Vázquez, P., Blázquez, C., Torres, S., García, S.... (2009) Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells. Journal of Clinical Investigation. DOI: 10.1172/JCI37948
- March 23, 2009
- 04:48 PM
- 381 views
Fine-Tuning Cell Adhesiveness
by Nick Anthis in The Scientific Activist
Cells in higher organisms exist in a dynamic environment, requiring the ability to alternately grasp and disengage from the three-dimensional web of their surroundings. One family of proteins in particular, the integrins, plays a key role in this process by acting as the hands of the cell. Spanning the cell membrane, they link the extracellular matrix to the cell's internal cytoskeleton. Integrins are especially interesting, though, because the cell uses them to uniquely pass signals in both directions across the membrane, and an integrin's adhesiveness for the extracellular matrix can be activated from within the cell by a protein called talin. This occurs through a direct protein-protein interaction between talin and the integrin.
Some biological processes call for exquisitely fine regulation of cell adhesiveness. When a cell migrates from one location to another in the body (as is necessary in growth, development, wound healing, and blood vessel formation, for example) integrins at the front of the cell need to make new contacts with the surroundings, but those in the rear need to disengage. Specifically, this requires the regulation of integrin activation by talin.
We have a new paper out this week in JBC (The Journal of Biological Chemistry) that explains part of this regulation in great structural detail. This work was done primarily by Ben Goult, a postdoc with David Critchley at the University of Leicester. Read the rest of this post... | Read the comments on this post...... Read more »
Goult, B., Bate, N., Anthis, N., Wegener, K., Gingras, A., Patel, B., Barsukov, I., Campbell, I., Roberts, G., & Critchley, D. (2009) The structure of an interdomain complex which regulates talin activity. Journal of Biological Chemistry. DOI: 10.1074/jbc.M900078200
- September 24, 2008
- 08:36 PM
- 476 views
Feedback on "Advancing Science Through Conversations"
by Nick Anthis in The Scientific Activist
Since our paper on the role of blogs in academia was published earlier this week, we've received quite a bit of feedback from the across blogosphere. Befittingly, the authors of the paper have contributed to this, as Tara gave her thoughts on her blog, I gave mine on my blog (Shelley has been busy traveling for interviews, so she hasn't had a chance to weigh in yet), and we published a list of acknowledgments. (I'd also like to thank our respective universities' press offices for their outreach efforts. I found Oxford particularly pleasant to work with, and they even put up something on their website--although it's a bit overly focused on me, as one might expect coming from my university).
Of course, we already knew what we thought, so let's see what others had to say. I'll start with some of the more favorable posts. In particular, Brian Switek of Laelaps, John Dennehy of The Evilutionary Biologist, and Dave Munger of ResearchBlogging all gave positive reviews, each from a different perspective. Munger focused on the role of ResearchBlogging, Dennehy draws on his own experiences, saying "blogging has been one of the best academic decisions I have ever made" and addressing those not convinced by pointing out that "back in 1994, hardly any labs had a web page, but now it seems obligatory". Switek gave his own case for the value of blogs in academia, one that runs parallel to the arguments we make in our paper. In particularly, I'd like to quote the following paragraph from Switek, because it is relevant to addressing some of the criticisms discussed below: Read the rest of this post... | Read the comments on this post...... Read more »
Shelley A. Batts, Nicholas J. Anthis, & Tara C. Smith. (2008) Advancing Science through Conversations: Bridging the Gap between Blogs and the Academy. PLoS Biology, 6(9). DOI: 10.1371/journal.pbio.0060240
- September 22, 2008
- 09:47 PM
- 468 views
Advancing Science through Conversations: Bridging the Gap between Blogs and the Academy
by Nick Anthis in The Scientific Activist
Just over a year ago, I joined fellow science bloggers Shelley Batts (Of Two Minds) and Tara Smith (Aetiology) in setting out to catalogue the accomplishments--and pitfalls--of the scientific blogosphere and to explain why people should pay attention. In a sense, we wanted to say "We are the science bloggers; hear us roar!" And, in order to make our case, we drew from the collective experience of our fellow science bloggers, far and wide, asking how blogging had affected their work, their careers, and their lives--both positively and negatively.
The results were astounding. Across the blogosphere, scientists had started new collaborations, enhanced their scientific work, advanced their careers, been able to communicate science as never before, and had been offered a whole array of new and unique experiences and opportunities in part or in full due to their blogs. In fact, the stories we heard were so compelling that instead of just communicating them we asked ourselves another question: why has this phenomenon gone so underreported and unappreciated within academic circles? And, more pointedly, how can we most effectively communicate this potential to an academic audience--in hopes of catalyzing even more of these wonderful successes?
I'm not sure if this is the answer, but our best effort at addressing this gulf between academia and the blogosphere was published today in PLoS Biology. In our paper, we address various instances of efforts to bring academia and blogging closer together, and we offer a series of suggestions for how academic institutions--and bloggers--might carry this forward to the next level. We believe that when bloggers and academic institutions work together, the result can be mutually beneficial for both parties, and can be carried out in a way that advances the institution's mission without destroying the independence that makes the blogosphere so powerful. By no means are we saying that all science bloggers would want to be more closely associated with an academic institution--far from it, actually--but we give suggestions for how this might be accomplished when deemed desirable. I won't say much more here--instead encouraging you to take a look at the paper yourself--except for offering you the take-home message of the paper in the form of its final paragraph: Read the rest of this post... | Read the comments on this post...... Read more »
Shelley A. Batts, Nicholas J. Anthis, & Tara C. Smith. (2008) Advancing Science through Conversations: Bridging the Gap between Blogs and the Academy. PLoS Biology, 6(9). DOI: 10.1371/journal.pbio.0060240
J WILKINS. (2008) The roles, reasons and restrictions of science blogs. Trends in Ecology , 23(8), 411-413. DOI: 10.1016/j.tree.2008.05.004
L Bonetta. (2007) Scientists Enter the Blogosphere. Cell, 129(3), 443-445. DOI: 10.1016/j.cell.2007.04.032
A. Ashlin and R.J. Ladle. (2006) Environmental Science Adrift in the Blogosphere. Science, 312(5771), 201-201. DOI: 10.1126/science.1124197
- July 31, 2008
- 09:01 AM
- 346 views
Water on Mars, Part 2
by Nick Anthis in The Scientific Activist
Below is the second part of my interview with planetary geologist Bethany Ehlmann. In the first part, she discussed two of her recent papers on Martian geology (see citations below). In this segment, she discusses water on Mars more generally.
Bethany Ehlmann Nick Anthis: Would it be possible to briefly take our readers through the history of the discovery of water (or traces of past water) on Mars? I know that this is an important area, but it seems like there's so much work on it coming out now that it's hard for someone not in the field to put it all into context. Maybe you could just tell us what the key discoveries were.
Bethany Ehlmann: Part of being a graduate student is that I'm still learning what's been done before. So with that caveat...
NA: I understand. I'm writing my PhD thesis now, and I'm certainly discovering things now in the literature that I wish I had known about before I started my work!
BE: I really think it goes all the way back to Percival Lowell's canali: artificial straight channels that he thought he saw in his telescope. It really captured the public and scientific imagination even though later scientists couldn't replicate his find. Read the rest of this post... | Read the comments on this post...... Read more »
Bethany Ehlmann, John F Mustard, Caleb I Fassett, Samuel C Schon, James W Head III, David J Des Marais, John A Grant, & Scott L Murchie. (2008) Clay minerals in delta deposits and organic preservation potential on Mars. Nature Geoscience, 1(6), 355-358. DOI: 10.1038/ngeo207
John Mustard, S L Murchie, S M Pelkey, B L Ehlmann, R E Milliken, J A Grant, J-P Bibring, F Poulet, J Bishop, E Noe Dobrea.... (2008) Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument. Nature, 454(7202), 305-309. DOI: 10.1038/nature07097
- July 30, 2008
- 08:39 AM
- 360 views
Water on Mars, Part 1
by Nick Anthis in The Scientific Activist
Planetary geology is a fascinating area--particularly when it pertains to the search for extraterrestrial life. I wrote about it once during my brief stint as a student science writer, but it's not an area that I've really covered on my blog. However, a former colleague of mine from Oxford, Bethany Ehlmann, was recently involved with a couple of papers on geological formations left by ancient Martian water, so I thought that this would be a perfect opportunity. Ehlmann is currently a PhD student in the geological sciences at Brown University and part of the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) team . Before that, she was a Rhodes Scholar at Oxford, where she completed two MSc degrees. She was recently the fourth author on a paper in Nature and just before that the first author on a paper in Nature Geoscience, both on Martian geology (see references below).
I've broken our interview into two parts. In the first part, published here, Ehlmann discusses her two recent papers. In the second part--which is published in a separate post--she discusses water on Mars more generally. Read the rest of this post... | Read the comments on this post...... Read more »
Bethany Ehlmann, John F Mustard, Caleb I Fassett, Samuel C Schon, James W Head III, David J Des Marais, John A Grant, & Scott L Murchie. (2008) Clay minerals in delta deposits and organic preservation potential on Mars. Nature Geoscience, 1(6), 355-358. DOI: 10.1038/ngeo207
John Mustard, S L Murchie, S M Pelkey, B L Ehlmann, R E Milliken, J A Grant, J-P Bibring, F Poulet, J Bishop, E Noe Dobrea.... (2008) Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument. Nature, 454(7202), 305-309. DOI: 10.1038/nature07097
- April 17, 2008
- 09:04 AM
- 336 views
Why Are Veins Blue?
by Nick Anthis in The Scientific Activist
When someone asks the question "why are veins blue?" a likely response is that they're blue because the blood in veins is deoxygenated. While it's true that venous blood vessels carry a lower concentration of oxygen than their arterial counterparts, this isn't the reason for their blue appearance in your skin. Still, when someone invariably responds to the veins-are-blue-because-they're-deoxygenated argument with the observation that "I've never seen blue blood before" one might then hear the slightly more sophisticated-sounding but increasingly far-fetched claim that we don't ever observ... Read more »
Alwin Kienle, Lothar Lilge, I. Vitkin, Michael Patterson, Brian Wilson, Raimund Hibst, & Rudolf Steiner. (1996) Why do veins appear blue? A new look at an old question. Applied Optics, 35(7), 1151-1160. http://www.imt.liu.se/edu/courses/TBMT36/pdf/blue.pdf
- February 11, 2008
- 10:02 PM
- 448 views
An Integrin Is Identified as a Co-Receptor for HIV
by Nick Anthis in The Scientific Activist
The New York Times reported yesterday that "scientists find new receptor for HIV," referring to a paper published online in Nature Immunology on Sunday by Arthos et al. This is basically correct, although it would be more accurate to call the new receptor a co-receptor, since the infection of a cell with HIV still depends on the primary receptor, CD4, in combination with either CCR5 or CXCR4. The newly-identified co-receptor, just like the other HIV receptors, is a protein located on the surface of white blood cells (T-cells, specifically). HIV, like any other virus, can only replicate w... Read more »
James Arthos, Claudia Cicala, Elena Martinelli, Katilyn Macleod, Donald Van Ryk, Danlan Wei, Zhen Xiao, Timothy Veenstra, Thomas Conrad, Richard Lempicki.... (2008) HIV-1 envelope protein binds to and signals through integrin α4β7, the gut mucosal homing receptor for peripheral T cells. Nature Immunology. DOI: 10.1038/ni1566
- February 5, 2008
- 08:02 AM
- 420 views
On Drugs, Circumcision, and John McCain
by Nick Anthis in The Scientific Activist
A few interesting items have recently come up in the news and in the scientific literature about various methods for preventing the transmission of HIV.
First up is a study (1) published in PLoS Medicine this week that demonstrated the effectiveness of a combination of antiretroviral drugs in preventing viral transmission in a monkey model of HIV. The researchers demonstrated that taking the antiretroviral drug emtricitabine (FTC) orally could reduce the chance that a macaque would become infected. Adding tenofovir-disoproxil fumarate (TDF) increased protection, and injecting both... Read more »
J García-Lerma, Ron A Otten, Shoukat H Qari, Eddie Jackson, Mian-er Cong, Silvina Masciotra, Wei Luo, Caryn Kim, Debra R Adams, Michael Monsour.... (2008) Prevention of Rectal SHIV Transmission in Macaques by Daily or Intermittent Prophylaxis with Emtricitabine and Tenofovir . PLoS Medicine, 5(2). DOI: 10.1371/journal.pmed.0050028
Paul Denton, Jacob D Estes, Zhifeng Sun, Florence A Othieno, Bangdong L Wei, Anja K Wege, Daniel A Powell, Deborah Payne, Ashley T Haase, & J Victor Garcia. (2008) Antiretroviral Pre-exposure Prophylaxis Prevents Vaginal Transmission of HIV-1 in Humanized BLT Mice. PLoS Medicine, 5(1). DOI: 10.1371/journal.pmed.0050016
- January 24, 2008
- 05:06 PM
- 392 views
Embryonic Stem Cell Debate Over; Thousands of Researchers Now Jobless
by Nick Anthis in The Scientific Activist
That could easily have been the shared title of a pair of articles in today's New York Times discussing the science and political implications of two very significant stem cell papers published online yesterday. The biggest offender was Sheryl Stolberg:
It has been more than six years since President Bush, in the first major televised address of his presidency, drew a stark moral line against the destruction of human embryos in medical research.
Since then, he has steadfastly maintained that scientists would come up with an alternative method of developing embryonic stem ce... Read more »
K TAKAHASHI, K TANABE, M OHNUKI, M NARITA, T ICHISAKA, K TOMODA, & S YAMANAKA. (2007) Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factors. Cell, 131(5), 861-872. DOI: 10.1016/j.cell.2007.11.019
J Yu, M Vodyanik, K Smuga-Otto, J Antosiewicz-Bourget, J Frane, S Tian, J Nie, G Jonsdottir, V Ruotti, R Stewart.... (2007) Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells. Science, 318(5858), 1917-1920. DOI: 10.1126/science.1151526
- January 24, 2008
- 05:06 PM
- 376 views
Stem Cells from Down Under
by Nick Anthis in The Scientific Activist
Two weeks ago, on November 15th, researchers reported in the Journal of Translational Medicine (see citation below) that they had successfully isolated and characterized stem cells from menstrual blood. The researchers, Meng et al., were able to differentiate these cells--called Endometrial Regenerative Cells (ERCs)--into nine distinct cell types, and the stem cells displayed other encouraging characteristics (including rapid proliferation, unique expression of an embryonic stem cell marker, and particularly high production of certain growth factors and matrix metalloproteinases). These f... Read more »
Xiaolong Meng, Thomas Ichim, Jie Zhong, Andrea Rogers, Zhenglian Yin, James Jackson, Hao Wang, Wei Ge, Vladimir Bogin, Kyle Chan.... (2007) Endometrial regenerative cells: A novel stem cell population. Journal of Translational Medicine, 5(1), 57. DOI: 10.1186/1479-5876-5-57
- January 24, 2008
- 05:06 PM
- 479 views
Best Headline Ever: "Creature from Hell Promises Salvation"
by Nick Anthis in The Scientific Activist
From today's (well, technically, tomorrow's) New Zealand Herald:
Creature from hell promises salvation
by Errol Kiong
Scientists have discovered a methane-eating bacterium at Hell's Gate in Rotorua which may offer hope for global warming.
Researchers at GNS Science hope their discovery of the bacterium could one day be used to cut down methane gas emissions from landfills and geothermal power stations.
The bug is part of a group of methane-eating micro-organisms known as methanotrophs, but this one is able to live in hotter and much more acidic conditions... Read more »
Peter Dunfield, Anton Yuryev, Pavel Senin, Angela V Smirnova, Matthew B Stott, Shaobin Hou, Binh Ly, Jimmy H Saw, Zhemin Zhou, Yan Ren.... (2007) Methane oxidation by an extremely acidophilic bacterium of the phylum Verrucomicrobia. Nature, 450(7171), 879-882. DOI: 10.1038/nature06411
Arjan Pol, Klaas Heijmans, Harry Harhangi, Dario Tedesco, Mike Jetten, & Huub Op den Camp. (2007) Methanotrophy below pH 1 by a new Verrucomicrobia species. Nature, 450(7171), 874-878. DOI: 10.1038/nature06222
- January 24, 2008
- 05:06 PM
- 470 views
Integrin Phosphorylation as an Off Switch for Integrin Activation
by Nick Anthis in The Scientific Activist
An individual cell inside the human body is in a dynamic environment: it not only has to anchor itself to its surroundings but also be able to communicate with them and respond as appropriate. One group of proteins--the integrins--play a central role in all of these tasks. The integrins are large (about 200,000 Da) membrane-spanning proteins, and each integrin consists of two subunits (alpha and beta). The vast majority of the integrin is located on the exterior of the cell, where it anchors the cell to the extracellular matrix. Each subunit has a short tail inside of the cell, and the... Read more »
C Oxley, N J Anthis, E D Lowe, I Vakonakis, I D Campbell, & K L Wegener. (2007) An integrin phosphorylation switch: the effect of beta3 integrin tail phosphorylation on DOK1 and talin binding. Journal of Biological Chemistry. DOI: 10.1074/jbc.M709435200
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