An Arabidopsis stomate showing two guard cells exhibiting green fluorescent protein and native chloroplast (red) fluorescence. via Wikipedia. This image is an extreme closeup of a stomate (singular, the plural form is stomata). These two cells, called guard cells, control the plant’s respiration: how much carbon dioxide gets in and how much oxygen and water vapor gets out. The control isn’t very good, though. Most plants just have their stomata open all day Continue reading...... Read more »
Hu H, Boisson-Dernier A, Israelsson-Nordström M, Böhmer M, Xue S, Ries A, Godoski J, Kuhn JM, & Schroeder JI. (2010) Carbonic anhydrases are upstream regulators of CO2-controlled stomatal movements in guard cells. Nature cell biology, 12(1), 87. PMID: 20010812
Will we have a universal Influenza vaccine someday? Will we find something that eliminates the need of developing a new vaccine every year and ensuring that great part of the population receives it?
The annual development of flu vaccines is a very expensive way of avoiding this disease even if it is the most efficient way. [...]... Read more »
Sui, J., Hwang, W., Perez, S., Wei, G., Aird, D., Chen, L., Santelli, E., Stec, B., Cadwell, G., Ali, M.... (2009) Structural and functional bases for broad-spectrum neutralization of avian and human influenza A viruses. Nature Structural , 16(3), 265-273. DOI: 10.1038/nsmb.1566
Wang, T., & Palese, P. (2009) Universal epitopes of influenza virus hemagglutinins?. Nature Structural , 16(3), 233-234. DOI: 10.1038/nsmb.1574
Why are there no perennial grain crops? That’s the provocative question posed by a recent paper in Evolutionary Applications written by three scientists working at The Land Institute. Whose institutional mission, of course, is to breed just this sort of crop, on the assumption that they “could reduce soil erosion while maintaining production of food [...]... Read more »
Van Tassel, D., DeHaan, L., & Cox, T. (2010) Missing domesticated plant forms: can artificial selection fill the gap?. Evolutionary Applications. DOI: 10.1111/j.1752-4571.2010.00132.x
An analysis of two recent publications describing two different systems that can penetrate solid tumors and deliver/distribute anti-cancer therapeutics throughout the tumor tissue, thereby improving treatment efficacy.... Read more »
Sugahara, K., Teesalu, T., Karmali, P., Kotamraju, V., Agemy, L., Greenwald, D., & Ruoslahti, E. (2010) Coadministration of a Tumor-Penetrating Peptide Enhances the Efficacy of Cancer Drugs. Science, 328(5981), 1031-1035. DOI: 10.1126/science.1183057
Davis, M., Zuckerman, J., Choi, C., Seligson, D., Tolcher, A., Alabi, C., Yen, Y., Heidel, J., & Ribas, A. (2010) Evidence of RNAi in humans from systemically administered siRNA via targeted nanoparticles. Nature, 464(7291), 1067-1070. DOI: 10.1038/nature08956
I recently received an email from a graduate student in Philosophy regarding protein function. Not sure if that person wants his name advertised, so I will keep it to myself.
I am a fan of your blog, and interested in the philosophy of biology. One particularly interesting question is what makes something have a function; when [...]... Read more »
Khersonsky O, Roodveldt C, & Tawfik DS. (2006) Enzyme promiscuity: evolutionary and mechanistic aspects. Current opinion in chemical biology, 10(5), 498-508. PMID: 16939713
Jeffery, C. (2003) Moonlighting proteins: old proteins learning new tricks. Trends in Genetics, 19(8), 415-417. DOI: 10.1016/S0168-9525(03)00167-7
I’m happy and proud to tell you that Lab Rat was kind enough to write today’s blogpost. She brings you a fascinating story about little magnetic particles found in some bacteria, that may help them find their way like compasses do. Normally she writes great posts on bacteria on her own blog, which [...]... Read more »
Komeili, A. (2006) Magnetosomes Are Cell Membrane Invaginations Organized by the Actin-Like Protein MamK. Science, 311(5758), 242-245. DOI: 10.1126/science.1123231
I read a paper today (actually, more like an essay) by Peter Wangersky, a longtime chemical oceanographer. Titled “Methods of sampling and analysis and our concepts of ocean dynamics,” it is essentially a personable ramble through six decades of marine science, reflecting on the technical capabilities and sampling methods over time and the [...]... Read more »
Peter J. Wangersky. (2005) Methods of sampling and analysis and our concepts of ocean dynamics. Scientia Marina, 69(S1), 75-84. info:/10.3989/scimar.2005.69s175
As I'm sure you're all aware by now, human life expectancy for both young and old in the most developed regions of the world is slowly increasing, and this has been the case for some time. As medical technology advances and our wealth grows, we benefit in ways that lead to less biochemical damage to the complex machinery of our body accumulated over the course of a lifetime - and thus a greater likelihood of living longer. That the medical and research establishments have achieved this ongoing benefit even in advance of any structured, deliberate, large-scale efforts to slow or (more preferably) repair the consequences of aging bodes well for the future. The scientific community should be able to achieve far more impressive results when they are actually trying to directly tackle aging. I noticed an open access paper today (PDF version included) that applies some mathematical wizardry so as to break out the most important structural contributions to increasing longevity. I think you'll find it interesting: The ongoing increase in life expectancy in developed countries is associated with changes in the shape of the survival curve. These changes can be characterized by two main, distinct components: (i) the decline...... Read more »
Rousson, V., & Paccaud, F. (2010) A set of indicators for decomposing the secular increase of life expectancy. Population Health Metrics, 8(1), 18. DOI: 10.1186/1478-7954-8-18
Our cells are dividing all the time – replacing worn-out cells and healing injuries. But cell division can be a tricky business – every time a cell divides, each one of its 46 chromosomes, and the DNA they are made of, must be copied perfectly. Time and time again the cells in our bodies divide [...]... Read more »
Lin, T., Letsolo, B., Jones, R., Rowson, J., Pratt, G., Hewamana, S., Fegan, C., Pepper, C., & Baird, D. (2010) Telomere dysfunction and fusion during the progression of chronic lymphocytic leukaemia: evidence for a telomere crisis. Blood. DOI: 10.1182/blood-2010-02-272104
Although he’s been dead for nearly 500 years, Leonardo da Vinci is still remembered as the quintessential Renaissance man, a polymath whose curiosity and creativity ranged widely among the arts and sciences. One of his interests was the study of fossils. In a new paper in the journal Palaios, Andrea Baucon shows that he was [...]... Read more »
BAUCON, A. (2010) LEONARDO DA VINCI, THE FOUNDING FATHER OF ICHNOLOGY. PALAIOS, 25(6), 361-367. DOI: 10.2110/palo.2009.p09-049r
I wonder what the loons at Age of Autism will say about this.
Actually, I know what they'll say. Whenever a scientific study like the one just published earlier this week the top tier journal Nature, which examines genetic variations (CNVs) associated with autism and autism spectrum disorders (ASDs), comes out, they have a standard reply. Even though, as of this writing, I haven't seen yet seen a reply on the anti-vaccine crank blog Age of Autism to the study I'm about to describe, I'm sure it's coming and I'm sure it will look something like this article from a year ago by Mark "Not A Scientist Not a Doctor" Blaxill entitled Latest Autism Gene Studies Find....Not Very Much:
There's a familiar rhythm to the most prominent autism gene hunt publications. Their authors hype their newly minted study aggressively in the media. The prestigious journals that publish them lend their imprimatur to press releases that say, "this study is a big deal." The findings sound impressive in the press release (and the authors get plenty of time on camera and in leading newspapers to tell us how truly impressive they are). In the meantime--in papers that are so densely written that making sense of what they really say requires far more reflection than the media hype cycle permits--skillfully concealed evidence reveals the truly important news in the findings: the authors whisper quietly (if at all) that the new analysis negates the most important findings of some of the most prominent previous gene hunts, while crucial detail on their new findings is often relegated to "supplementary material" that's not available on the publication date.
Such a declaration is then almost inevitably followed by rants against scientists for concentrating on genes rather than vaccines as a cause of autism, claims of "conflicts of interest," and an "analysis" of the findings of the study that betray an incredible lack of understanding of molecular biology, genetics, and developmental biology. I expect that the response to this study will be no different and may well appear on AoA by tomorrow morning, quite possibly written by Mark "Not a Scientist Not a Doctor" Blaxill. The study by Pinto et al, looks at the functional impact of global rare copy number variation in autism spectrum disorders. Read the rest of this post... | Read the comments on this post...... Read more »
Pinto, D., Pagnamenta, A., Klei, L., Anney, R., Merico, D., Regan, R., Conroy, J., Magalhaes, T., Correia, C., Abrahams, B.... (2010) Functional impact of global rare copy number variation in autism spectrum disorders. Nature. DOI: 10.1038/nature09146
Sci has constantly been annoyed that no one seems to have performed a real, thorough study on the sensitivity of the vagina. Or at least, it's beyond her pubmed-fu. If someone has done it, please let me know! I'd really like to cover it and I'm very annoyed that I cannot seem to find it. Sci is also annoyed by this because several studies have covered the sensitivity of the penis. It's just not fair.
But today, Sci was pubmedding furiously, and she FOUND SOMETHING. I am so excited.
Foldes and Buisson. "The Clitoral Complex: A Dynamic Sonographic Study" Journal of Sexual Medicine, 2009.
YES! Not the whole thing, but it's a start.
I suppose you could say the pictures below are NFSW. But they're sonograms. So it could be anything, really, and most people won't know. If your boss comes up behind you, tell them you're looking at someone's baby pics. Read the rest of this post... | Read the comments on this post...... Read more »
The human immune system of tomorrow will look, conceptually, a lot like today's software defenses: Scientists are making real inroads into replicating and controlling the cells and mechanisms of our immune system. Producing immune cells, directing their actions, deciphering the biochemistry of pathogens - all these pieces are waiting to be put together as a bioartificial immune system, many times more selective, efficient and resistant to damage than the basic version we're all equipped with. ... One might imagine the future providers of immune system technology looking a lot like today's providers of anti-virus software for your computers, harvesting information on potential infections and streaming update information to bioartificial antibody manufactories in your bloodstream. Wireless anti-virus nanotechnology in the blood may seem like a far future vision, but the first building blocks of that technology are already emerging from present day research. For example, it won't be long before clinics can assemble massive doses of artificial antibodies to order and then infuse them into your body. Antibodies are the immune system's weapons, molecules tailored to a specific threat that either directly kill attackers or flag them for ingestion and destruction by white blood cells. An infusion of antibodies produced in...... Read more »
Hoshino, Y., Koide, H., Urakami, T., Kanazawa, H., Kodama, T., Oku, N., & Shea, K. (2010) Recognition, Neutralization, and Clearance of Target Peptides in the Bloodstream of Living Mice by Molecularly Imprinted Polymer Nanoparticles: A Plastic Antibody. Journal of the American Chemical Society, 132(19), 6644-6645. DOI: 10.1021/ja102148f
"Dinah", a young female gorilla kept at the Bronx Zoo in 1914. From the Zoological Society Bulletin.
Frustrated by the failure of gorillas to thrive in captivity, in 1914 the Bronx Zoo's director William Hornaday lamented "There is not the slightest reason to hope that an adult gorilla, either male or female, ever will be seen living in a zoological park or garden." Whereas wild adult gorillas were "savage" and "implacable" beasts which could not be captured (a photo of a sculpture included in Hornaday's article depicts a gorilla strangling one man, brandishing another about with its other arm, and standing on the body of a third), young gorillas were fragile animals that did not last long in the concrete and steel enclosures made for them. One gorilla in Germany had survived for seven years, but the average lifespan of a captive juvenile gorilla was about nine months, and often considerably less than that. This was not to say that zoological parks would stop trying to capture and import young gorillas - Hornaday gave no indication that he wished to stop procuring young gorillas for his zoo - but only that visitors to the Bronx Zoo and other menageries would probably never see an adult gorilla.
Zoos had been failing miserably at keeping apes in captivity for centuries. Most of the animals captured were young individuals which had been snatched from their families or had just been orphaned by specimen collectors. They regularly died on the journey out of Africa or shortly after they arrived at their public confines. Many refused to eat, and most would become sick before passing away, but why this should be so puzzled zoologists. Perhaps, they speculated, it was a matter of climate. The cooler climates of Europe and North America were poor proxies for equatorial Africa, so it was hardly surprising that morality was so high.
Looking back at the practices of zoos during the early 20th century, however, it is apparent that the different climates of Europe and North America cannot solely be blamed for the deaths of these apes. The traditional methods of catching and collecting wild animals which had worked for many other species caused a great deal of stress for captured apes, and the concrete and steel enclosures in which they were placed were cruel by today's standards. (Though, even under today's improved conditions, it can still be questions whether zoos are capable of keeping apes happy and healthy.) Still, in reference to climate, what is curious about the modern disparity between Africa and the places to which the young apes were shipped is that, not so very long ago, much of the northern hemisphere was inhabited by a variety of apes species. North American never had apes, but Europe and much of Asia did, making today's ape species the tattered branches of what once was a richer family tree.
Read the rest of this post... | Read the comments on this post...... Read more »
Merceron, G., Kaiser, T., Kostopoulos, D., & Schulz, E. (2010) Ruminant diets and the Miocene extinction of European great apes. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2010.0523
DUNHAM, A., ERHART, E., & WRIGHT, P. (2010) Global climate cycles and cyclones: consequences for rainfall patterns and lemur reproduction in southeastern Madagascar. Global Change Biology. DOI: 10.1111/j.1365-2486.2010.02205.x
There has been a lot of talk about brain plasticity, the idea that our brains can be shaped and moulded by experience, in popular books and articles over the past several years. The notion that new neurons can be born in our brains, even in adulthood, is gripping and at times very encouraging.However, our brains are not nearly as plastic as the more primitive brains of fish, amphibians and birds. Some of these organisms experience fluctuations in brain volume so drastic that if they existed in humans, they would probably leads to startling changes in intelligence and behaviour throughout adult life.In birds, changes in singing behaviour that occur as the seasons change are linked to radical changes in the size of brain regions that control singing (explained here). During mating season, when birds sing more, new neurons are born (i.e. neurogenesis) in the song control system, whereas neurons die during the offseason.Neurogenesis occurs in widespread regions of adult bird brains, making them a good model for the studying the mechanism of neuron birth. In mammals, neurogenesis has only been identified in the hippocampus and the olfactory bulb. In humans, most research attention is given to the hippocampus because of its prominent roles in memory and cognition.David Sherry and Jennifer Hoshooley at the University of Western Ontario recently published a review on the study of plasticity/neurogenesis in the hippocampus of birds who store food during specific seasons. The authors discuss studies that show changes in hippocampal size and neurogenesis during periods of food-storing behaviour. They propose that hippocampal neurogenesis may be a consequence of the behavioural and cognitive involvement of the hippocampus in storing and retrieving food.It is important to note, however, that it is difficult to directly link hippocampal neurogenesis to food-storing behaviour when this type of behaviour always comes during a specific season that is associated with changes in social system, size and appearance of home range, and diet. Important evidence that supports the notion that hippocampal neurogenesis is due to food-storing behaviour alone comes from studies of food-storing birds (e.g. chickadees) versus non-storing birds (e.g. house sparrows). The non-storing birds experience the same environmental changes as food-storing birds, but the food-storing birds show much more hippocampal neurogenesis than the non-storing birds (a study that showed this was conducted by David Sherry’s group).It thus appears that hippocampal plasticity is linked to food-storing behaviour, an activity that involves memorizing multiple locations at once – something that birds are very good at. What remains to be seen is the aspect(s) of food-storing behaviour that the hippocampus is important for. We know that a reliable way to stimulate hippocampal neurogenesis in mammals is getting them to exercise. Could it be that birds are much more physically active during food-storing season, and could this account for the birth of new neurons? Neurogenesis is extensively studied in birds, but the question of exercise and neurogenesis has not been directly investigated. We know that we share genes with birds that control language and singing; perhaps further study of plasticity and neurogenesis will illuminate more similarities between us and our flying friends.References:Sherry DF, & Hoshooley JS (2010). Seasonal hippocampal plasticity in food-storing birds. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365 (1542), 933-43 PMID: 20156817Hoshooley JS, & Sherry DF (2007). Greater hippocampal neuronal recruitment in food-storing than in non-food-storing birds. Developmental neurobiology, 67 (4), 406-14 PMID: 17443797... Read more »
Sherry DF, & Hoshooley JS. (2010) Seasonal hippocampal plasticity in food-storing birds. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365(1542), 933-43. PMID: 20156817
Hoshooley JS, & Sherry DF. (2007) Greater hippocampal neuronal recruitment in food-storing than in non-food-storing birds. Developmental neurobiology, 67(4), 406-14. PMID: 17443797
It goes without saying that tomorrow, June 11, 2010, literally kicks off the FIFA 2010 World Cup in South Africa. The media has been throwing around stories on projected winners, South Africa’s history in the making and even possible flu outbreaks from vuvuzelas. Fans around the world wait in anticipation; meanwhile in South Africa, staff from the Global Environment Facility (GEF), the United Nations Environment Program (UNEP) and the South African Department of Environmental Affairs (DEA) are trying to meet an ambitious “green” goal.
... Read more »
How does natural selection account for language? Darwin wrestled with it, Chomsky sidestepped it, and Pinker claimed to solve it. Discerning the evolution of language is therefore a much sought endeavour, with a vast number of explanations emerging that offer a plethora of choice, but little in the way of consensus. This is hardly new, [...]... Read more »
Deacon, T. (2010) Colloquium Paper: A role for relaxed selection in the evolution of the language capacity. Proceedings of the National Academy of Sciences, 107(Supplement_2), 9000-9006. DOI: 10.1073/pnas.0914624107
Intracellular parasites have a difficult life. On the one hand, they need to utilise the resources of the host cell, which will ultimately cause it damage, however on the other they must necessarily keep the host cell alive so that they can live off it. This is particularly difficult when your host cell is a eukaryote cell in a multicellular organism, because multicellular organisms can't afford to have one cell behaving oddly. If the cell starts to notice any differences in its behaviour, it promptly commits suicide, meaning that in order for the parasite to survive it has to find ways of preventing the cell from killing itself when it notices things going wrong.Chlamydia is a particularly well studied human intracellular bacteria, and is best known for being sexually transmitted and featuring in posters on student welfare notice boards in probably every university in the UK:If it's worth talking about, it's worth blogging about!The reason Chlamydia is so worth talking about is two-fold, firstly because it's a bacterium rather than a virus and can therefore be (relatively) easily treated with antibiotics. Secondly, because you don't always know you have it and therefore it's worth getting tested even if you don't appear to have any symptoms. The bacteria can live perfectly happily within your cells replicating away without the body noticing, and if left untreated can lead to quite serious problems, such as blindness, pelvic inflammation or sterility.In order to remain replicating inside the cells unnoticed for so long, Chlamydia have to prevent the cells from either destroying them or committing suicide before they manage to replicate. One of the ways they can do this is by degrading the cell proteins involved in cell signalling pathways. An example is the serine protease (i.e an enzyme that breaks down proteins) CPAF which is secreted by the infective chlamydia particles and (among other things) breaks down the protein HIF-1 which is used to trigger the cell suicide response to low oxygen levels. They can also break down proteins which would potentially be involved in the immune responses to the damaged cell, such as NF-KB, which helps activate the innate immune system inflammatory response.Quite how the chlamydia causes the host cell protein degradation is still a little unclear. They may use the common viral strategy of modifying proteins to make them more susceptible to being picked up by the cellular degradation machinery (although there is no biochemical evidence for this as yet) or alternatively it might activate protein degradation pathways that are usually silenced in uninfected cells. Analysis of the chlamydia genome shows several predicted proteases, so it may be possible that rather than using host proteases the bacteria is degrading specific proteins with its own protease enzymes. The bacterial protease CPAF (mentioned above) has been crystallised and the crystal structure shows the potential for several different substrates (i.e it could potentially degrade many different proteins) so it might play in important part in this process. The use of degradation proteins also creates a potential target for therapeutics. If that sentence sounds familiar it's because I've written it several times before and will probably write it several times in the future. "New targets for therapeutics" is pretty much THE standard excuse for studying anything related to bacteria. From a more selfish and less funding-motivated standpoint, it also provides exciting new information about how bacterial and eukaryotic cells interact, and how parasites that live inside cells can control host signalling pathways to their own advantage.---Zhong G (2009). Killing me softly: chlamydial use of proteolysis for evading host defenses. Trends in microbiology, 17 (10), 467-74 PMID: 19765998---Follow me on Twitter!... Read more »
Zhong G. (2009) Killing me softly: chlamydial use of proteolysis for evading host defenses. Trends in microbiology, 17(10), 467-74. PMID: 19765998
Sloths are mostly known as rather slow-moving adorable creatures that spend their days eating leaves and sleeping. However, a recent paper in the journal Mammalian Biology shows they might actually have a side to them that makes them a little less adorable: they were found to have developed the charming habit of climbing into an outdoor toilet and eating its contents!Read more about our weird and fascinating natural world at:Mudfooted.com
... Read more »
Heymann, E., Flores Amasifuén, C., Shahuano Tello, N., Tirado Herrera, E., & Stojan-Dolar, M. (2010) Disgusting appetite: Two-toed sloths feeding in human latrines. Mammalian Biology - Zeitschrift fur Saugetierkunde. DOI: 10.1016/j.mambio.2010.03.003
There will be ten thousand subtle gene variants of human longevity. Or rather, these differences between individuals most likely exist now and will be steadily uncovered in the years ahead as the cost of DNA sequencing continues to fall. Most of these longevity-associated genetic variants will look much like this one: an association discovered by comparing long-lived people to average members of the population, and neither terribly exciting nor particularly exploitable: Cytokines are crucial for the regulation of inflammation development in humans. Many studies have shown that variations in cytokine genes might play a role in determining human longevity. This study examined the changes in the gene pool relevant to the -308 G/A polymorphism in the promoter region of the proinflammatory cytokine tumour necrosis factor (TNF)-alpha gene and the -1082 G/A polymorphism in the promoter region of anti-inflammatory cytokine interleukin (IL)-10 gene with aging and survival selection occurs in the Jordanian population. .. the IL-10 genotype and allele frequencies were significantly associated with longevity in men but not in women. We should expect to see subtle associations with human longevity in genes associated with processes known to be important in long-term health - such as the inflammatory response, or indeed...... Read more »
Khabour OF, & Barnawi JM. (2010) Association of longevity with IL-10 -1082 G/A and TNF-alpha-308 G/A polymorphisms. International journal of immunogenetics. PMID: 20518833
Do you write about peer-reviewed research in your blog? Use ResearchBlogging.org to make it easy for your readers — and others from around the world — to find your serious posts about academic research.
If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.
Research Blogging is powered by SMG Technology.
To learn more, visit seedmediagroup.com.