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01-28-2014, 05:37 PM | #1276 |
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I think it's a rock that some angry Martian threw at the rover for driving through his lawn!
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01-28-2014, 06:00 PM | #1277 | |
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01-28-2014, 06:00 PM | #1278 | |
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01-28-2014, 06:01 PM | #1279 |
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01-29-2014, 03:53 PM | #1280 |
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Viruses. Not many pleasant thoughts associated with that word. Discovered just over 100 years ago, we've been slowly understanding them ever since. Initially it was thought that all viruses were bad. But now we know that's not the case. Viruses are now understood to be a very important part of our biosphere. And in much more abundance than we ever imagined...
An Ocean of Viruses Viruses abound in the world’s oceans, yet researchers are only beginning to understand how they affect life and chemistry from the water’s surface to the sea floor. There are an estimated 10^31 viruses on Earth. That is to say: there may be a hundred million times more viruses on Earth than there are stars in the universe. The majority of these viruses infect microbes, including bacteria, archaea, and microeukaryotes, all of which are vital players in the global fixation and cycling of key elements such as carbon, nitrogen, and phosphorus. These two facts combined—the sheer number of viruses and their intimate relationship with microbial life—suggest that viruses, too, play a critical role in the planet’s biosphere. Of all the Earth’s biomes, the ocean has emerged as the source for major discoveries on the interaction of viruses with their microbial hosts.1,2,3 Ocean viruses were the inspiration for early hypotheses of the so-called “viral shunt,” by which viral killing of microbial hosts redirects carbon and nutrients away from larger organisms and back toward other microorganisms.4,5 Furthermore, researchers analyzing oceanic life have discovered many novel viruses that defy much of the conventional wisdom about what a virus is and what a virus does. Among these discoveries are “giant” marine viruses, with capsid cross-sections that can exceed 500 nm, an order of magnitude larger than prototypical viruses. Giant viruses infect eukaryotic hosts, including the protist Cafeteria and unicellular green algae.6,7 These viruses also carry genomes larger than nearly all previously identified viral types, in some cases upwards of 1 million base pairs. In both marine and nonmarine contexts, researchers have even identified viruses that can infect giant viruses, the so-called virophages,8 a modern biological example of Jonathan Swift’s 17th-century aphorism: “a flea/ Hath smaller fleas that on him prey;/ And these have smaller fleas to bite ’em;/ And so proceed ad infinitum.” It is apparent that we still have much to learn about the rich and dynamic world of ocean microbes and viruses. For example, a liter of seawater collected in marine surface waters typically contains at least 10 billion microbes and 100 billion viruses—the vast majority of which remain unidentified and uncharacterized. Thankfully, there are an increasing number of high-throughput tools that facilitate the study of bacteriophages and other microbe-infecting viruses that cannot yet be cultured in the laboratory. Indeed, studying viruses in natural environments has recently gone mainstream with the advent of viral metagenomics, pioneered by Forest Rohwer and colleagues at San Diego State University in California.9 More recently, culture-free methods have enabled insights into questions beyond that of characterizing viral diversity. For example, Matthew Sullivan’s group at the University of Arizona and colleagues recently developed an adapted “viral tagging” method, by which researchers can now characterize the genotypes of environmental viruses that infect a host of interest, even if those viruses cannot be isolated in culture.10 These and other techniques—and the increasingly interdisciplinary study of environmental viruses—bring the scientific community ever closer to a clearer understanding of how viruses shape ocean ecology. Not so picky Researchers have long believed viruses to be extremely host-specific, meaning they should infect a taxonomically narrow subset of the microbial community at a given time in any given environment. But recent evidence suggests that marine viruses may not be so picky after all, and may be capable of infecting multiple microbial species or even more distantly related organisms. For example, a 2003 study demonstrated that certain cyanophage genotypes can infect not only different strains within the same cyanobacteria species, but different cyanobacterial genera as well.11 And a 2011 analysis of more than 20 years of viral-host infection assays revealed that naturally occurring viruses from a diversity of taxa range from specialists to generalists.12 Hence, viruses are certainly not limited to a single host genotype, nor to a particular species, and perhaps not even to a genus! Ostensibly, viruses should decrease the oceanic abundance of the targeted microbial lineage. Quantitative estimates of virus-mediated killing demonstrate that viruses are, in some cases, as important as grazers, such as protists and zooplankton, in selectively killing microbes. Such a relationship might, as a consequence, lead to dynamic fluctuations in viral and microbial populations, as viruses deplete susceptible bacteria. Indeed, new viral subtypes arise frequently and rapidly, and previously rare subtypes can quickly increase in abundance. Nonetheless, direct evidence for coupled oscillations in virus-microbe systems in the oceans is limited. It’s even possible that viruses do not play a strong role in controlling a microbe’s population. Or, in some instances, marine viruses that actively infect and lyse microbes may simply not have been accounted for in prior surveys. For example, until recently, the most abundant marine bacterial lineage, SAR11—estimated to make up a third of all prokaryotic cells in surface waters—had no documented viruses that were known to infect it, leading to speculations that SAR11’s observed high abundance was due, in part, to its lack of a phage predator. However, scientists recently discovered a group of non-tailed podoviruses that can and do kill SAR11. These viruses, previously unknown to science, are now estimated to be the most abundant viral type in the oceans and could be an important factor in driving changes in SAR11 populations.13 Where do all the nutrients go? The death of a host cell and the release of viral progeny are but one part of the story of how viruses affect the ocean ecosystem. Lysis of microbes also releases carbon and other organic nutrients, previously tied up as cellular materials, back into the environment. Marine microbes can assimilate these organic materials, leading to a paradoxical consequence of viral infection: the death of one host may indirectly benefit other microbes. This hypothesis, which we term “viral priming,” has been documented in experimental model systems using microbes that predominantly occur near the ocean surface. In one illustrative example, viral lysis of a bacterium infected in the lab released organic-iron complexes that were rapidly taken up by other marine bacteria, as well as by diatoms (unicellular eukaryotic algae).14 This assimilation increased growth rates of the nontargeted organisms. In a second example, the removal from an experimental system of viruses that infect and lyse heterotrophs slowed Synechococcus cell growth and proliferation, presumably due to a decrease in virus-mediated nutrient release.15 Thus, what is bad for one microbial cell may indeed be good for others. In the deep ocean, however, we still do not yet know what happens to virus-released organic matter. Is it assimilated, buried, or otherwise exported? What happens to organic matter miles below the surface is important because it closes the loop of the global carbon cycle. Free carbon in the deep ocean is “ancient” (4,000–6,000 years old) and largely recalcitrant to assimilation by microbes, suggesting there may be another supply of this material. Viral lysing of deep-ocean microbes may be a potential source.16 Furthermore, even before lysis, the infection of microbes alters host metabolism. Virus-induced changes in host metabolism can be so significant that the resulting infected particle is, biochemically and metabolically, a very different cell. For example, phage-infected cyanobacteria exhibit a higher rate of photosynthesis than their noninfected counterparts, presumably changing their rate of fixation of carbon from the environment until they are eventually killed by the infection. Bacterial cells undergoing active phage infections can also have altered distributions of other major elements, such as nitrogen and phosphorus, making them biochemically unique. Moreover, viruses can establish persistent infections within their microbial host cells—similar to infections established by viruses within large eukaryotic hosts, as occurs in the case of retroviral infections—by integrating their genomic material into that of their host, forming what is called a “lysogen.” (See diagram above.) The fate of infected cells may itself be coupled with the availability of carbon and nutrients in the environment. A recent study found that marine phages were more likely to initiate lysogeny, instead of lysis, when their hosts were nutrient-depleted.17 Hence, viruses that may “want” to lyse their hosts may not be able to—or, perhaps, they have evolved to respond to host physiology so as to kill their hosts only when it is more likely that other healthy hosts will be available to infect, which may be indicated by the physiological status of their current host. However, lysogeny is often harder to detect than lysis because the viruses are largely “hidden” within the host. In future, our understanding of viral-host interactions will need to take into account not just who infects whom, but what happens after that. Viruses, in theory Given the difficulties in quantifying the role viruses play in complex environments, researchers have turned to mathematical models to help shed light on what viruses might be doing to their hosts and the consequences of such interactions for the ocean system. Like many mathematical models in biology, these models can be very useful in making qualitative and quantitative predictions and in making sense of complex processes. But they also make simplifying assumptions. So, what do these models assume, what have they helped discover, and how can they help shape what we know about viral interactions with their hosts? Answering these questions requires an illustrative example. Here, we briefly discuss models that examine changes in the population densities of hosts and viruses in a community. Consider the question: How does the population size of a particular bacterial lineage depend on interactions with a particular set of viruses? Mathematical models deconstruct interactions between hosts and their environment, between viruses and hosts, and between viruses and the environment. For example, the infection of a marine cyanobacterium by a cyanophage can lead to lysis in approximately 12 hours. The net effect is the death of a host cell, the release of ~50 progeny viruses, and the release of organic material from the original cell as both virus particles and cellular debris. Hence, a model may ignore the complicated intracellular dynamics and focus on the output, breaking down the entire process in terms of a representative “chemical” reaction, such as 1 Host + 1 Virus = 50 Viruses. Then, the population dynamics of hosts and viruses can be derived from these reactions just as one would derive chemical reaction kinetics. The art of modeling is to decide when and where details matter. The details, however, depend on the question. Hence, efforts to characterize intracellular dynamics of infected cells require consideration of gene-gene interactions, and particularly the interaction of viral gene products with host physiology. Likewise, efforts to characterize extracellular dynamics require understanding of the rate at which hosts and viruses interact, particularly in complex environments. Perhaps the most exciting innovation in the area of virus-host modeling is the study of coevolutionary dynamics. Unlike in most models of chemical kinetics, the components (hosts and viruses) evolve over time. Coevolutionary models are technically challenging, given that the genotypes in the community (and in the model) must keep changing. Nonetheless, such models have been used to generate key hypotheses regarding the long-term dynamics of diverse microbial and viral populations. For example, an evolutionary kill-the-winner model was used to suggest that viral and bacterial strains may change rapidly even as total population size and total diversity remain relatively constant.18 Similarly, coevolutionary models have suggested that long-term coexistence of diverse microbial and viral communities should be expected, so long as there are trade-offs between infection and other host physiological rates, such as growth rate or nutrient uptake rate.19 The challenge is to reconcile model predictions with biological reality. For example, Debbie Lindell’s group at Technion–Israel Institute of Technology recently discovered a novel trade-off in which hosts that evolve resistance to certain viral infections may be increasingly susceptible to infection by other viral types with which they have not coevolved.20 This type of discovery further supports the need for considering viral-host interactions in a dynamic community context. It’s a microbial and viral world The potential role of viruses in marine biogeochemical cycles has been discussed for nearly 2 decades now, yet the quantitative influence that viruses have at regional and global scales remains largely unresolved. Fortunately, there is a growing interest in the ecological role of ocean viruses. Indeed, as marine microbiologist Mya Breitbart of the University of South Florida posed it, the science of environmental viruses is entering into an exciting period of “truth or dare.”3 That is to say, there are many established tenets of viral-host interactions in the oceans that are oft-repeated, but that are just now being put to the test. There are also many tenets that researchers should be “dared” to prove, or at least further substantiate. Indeed, a working group that we organized to study ocean viral dynamics at the University of Tennessee’s National Institute for Mathematical and Biological Synthesis is but one example of collaborations amongst experimentalists and modelers to characterize viral-host interactions and their consequences on a global scale. If the working group is any guide, future work on ocean viruses will include efforts to combine virus-driven biogeochemical processes, molecular biological data, and mathematical models in a unified context. A better quantitative assessment of the role of viruses in the ocean will have important implications for understanding past trends in, and future changes to, the Earth system. Curtis Suttle of the University of British Columbia has estimated that ocean viruses may turn over as much as 150 gigatons of carbon per year1—more than 30 times the standing abundance of carbon in marine plankton. This recycling of carbon and other nutrients suggests that viruses need to be considered in quantitative, dynamic models of global change. Global-change models integrate geophysical processes with the biology of microbes and metazoans to predict the dynamics of carbon nutrients and biodiversity. However, the smallest yet most abundant biotic agents on the planet—viruses—are rarely, if ever, included in such models. As the Intergovernmental Panel on Climate Change noted in a 2007 report (our emphasis): “The overall reaction of marine biological carbon cycling (including processes such as nutrient cycling as well as ecosystem changes including the role of bacteria and viruses) to a warm and high-CO2 world is not yet well understood. Several small feedback mechanisms may add up to a significant one.”
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01-29-2014, 04:02 PM | #1281 |
Ain't no relax!
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The Gympie-Gympie. Perhaps the worst choice of natural buttwipe....
Gympie Gympie: Once stung, never forgotten MARINA HURLEY'S DEDICATION TO science was sorely tested during the three years she spent in Queensland’s Atherton Tableland studying stinging trees. The entomologist and ecologist’s first encounter with the Gympie-Gympie stinging tree produced a sneezing fit and left her eyes and nose running for hours. Even protective particle masks and welding gloves could not spare her several subsequent stings – one requiring hospitalisation – but that was nothing compared with the severe allergy she developed. “Being stung is the worst kind of pain you can imagine - like being burnt with hot acid and electrocuted at the same time,” said Marina, who at the time was a postgraduate student at James Cook University investigating the herbivores that eat stinging trees. “The allergic reaction developed over time, causing extreme itching and huge hives that eventually required steroid treatment. At that point my doctor advised that I should have no further contact with the plant and I didn’t object.” She is not alone in her allergic reaction to this innocent-looking plant – one of six stinging-tree species found in Australia, and one of the most poisonous plants here – or her dramatic accounts. Proliferating in rainforest clearings, along creek-lines and small tracks, the Gympie-Gympie stinging tree (Dendrocnide excelsa) has long been a hazard for foresters, surveyors and timber workers – some of whom are today supplied with respirators, thick gloves and anti-histamine tablets as a precaution. More recently, the hairs covering the plant’s stems, leaves and fruits have also posed a danger to scientists and bushwalkers. Gympie-Gympie stinging tree history North Queensland road surveyor A.C. Macmillan was among the first to document the effects of a stinging tree, reporting to his boss in 1866 that his packhorse “was stung, got mad, and died within two hours”. Similar tales abound in local folklore of horses jumping in agony off cliffs and forestry workers drinking themselves silly to dull the intractable pain. Writing to Marina in 1994, Australian ex-serviceman Cyril Bromley described falling into a stinging tree during mili*tary training on the tableland in World War II. Strapped to a hospital bed for three weeks and administered all manner of unsuccessful treatments, he was sent “as mad as a cut snake” by the pain. Cyril also told of an officer shooting himself after using a stinging-tree leaf for “toilet purposes”. He’s had too many stings to count but Ernie Rider will never forget the day in 1963 that he was slapped in the face, arms and chest by a stinging tree. “I remember it feeling like there were giant hands trying to squash my chest,” he said. “For two or three days the pain was almost unbearable; I couldn’t work or sleep, then it was pretty bad pain for another fortnight or so. The stinging persisted for two years and recurred every time I had a cold shower.” Now a senior conservation officer with the Queensland Parks and Wildlife Service, Ernie said he’s not experienced anything like the pain during 44 years work in the bush. “There’s nothing to rival it; it’s 10 times worse than anything else – scrub ticks, scrub itch and itchy-jack sting included. Stinging trees are a real and present danger.” Gympie-Gympie: stings like acid So swollen was Les Moore after being stung across the face several years ago that he said he resembled Mr Potato Head. “I think I went into anaphylactic shock and it took days for my sight to recover,” said Les, a scientific officer with the CSIRO Division of Wildlife and Ecology in Queensland, who was near Bartle Frere (North Peak) studying cassowaries when disaster struck. “Within minutes the initial stinging and burning intensified and the pain in my eyes was like someone had poured acid on them. My mouth and tongue swelled up so much that I had trouble breathing. It was debilitating and I had to blunder my way out of the bush.” It was perhaps this rapid and savage reaction that inspired the British Army’s interest in the more sinister applications of the Gympie-Gympie stinging tree in 1968. That year, the Chemical Defence Establishment at Porton Down (a top-secret laboratory that developed chemical weapons) contracted Alan Seawright, then a Professor of Pathology at the University of Queensland, to dispatch stinging-tree specimens. “Chemical warfare is their work, so I could only assume that they were investigating its potential as a biological weapon,” said Alan, now an honorary research consultant to the University of Queensland’s National Research Centre in Environmental Toxicology. “I never heard anything more, so I guess we’ll never know.”
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01-29-2014, 04:17 PM | #1282 |
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^ **** that noise
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01-29-2014, 04:36 PM | #1283 |
Ain't no relax!
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So...... that mystery Mars rock? Some dumbshit is suing NASA over it....
Lawsuit Alleges NASA Is Failing To Investigate Alien Life You may recall, NASA recently announced that a strange rock had somehow "appeared" in front of its Mars Opportunity rover. The explanations for the mystery rock were straight-forward: maybe some kind of nearby impact sent a rock toward the rover, or, more likely, the rover knocked the rock out of the ground and no one noticed until later. Not so, says self-described scientist Rhawn Joseph, an author of trade books on topics ranging from alien life to the Sept. 11 terrorist attacks. (Sample article: "Dreams and Hallucinations: Lifting the Veil to Multiple Perceptual Realities.") The rock was a living thing, and he's filed a lawsuit to compel NASA to examine the rock more closely. Joseph is involved with the Journal of Cosmology, online publisher of some very controversial papers. In fact, this isn't the first report of alien life to come out of the journal. For the record: NASA has identified it as a rock. A very special rock, with rare properties, even. But definitely a rock. Okay? Good. The lawsuit, filed yesterday in a California court, is aimed at NASA and its Administrator, Charles Bolden, requesting that the agency "perform a public, scientific, and statutory duty which is to closely photograph and thoroughly scientifically examine and investigate a putative biological organism." Joseph is disputing the rock theory, since, "when examined by Petitioner the same structure in miniature was clearly visible upon magnification and appears to have just germinated from spores." (Joseph is the Petitioner.) The "rock," according to the lawsuit, was there the whole time, it just grew until it became visible. "The refusal to take close up photos from various angles, the refusal to take microscopicimages of the specimen, the refusal to release high resolution photos, is inexplicable, recklessly negligent, and bizarre," according to the suit. Joseph has contacted multiple NASA employees and provided them with said evidence, according to the lawsuit, but they have failed to respond. Outrage. Here are his requests of NASA: Petitioner has specifically requested and has demanded in writing the following of NASA, NASA’s chief administrator Bolden, and NASA’s rover team: A) take 100 high resolution close-up infocus photos of the specimen identified in Sol 3540, at various angles, from all sides, and from above down into the "bowl" of the specimen, and under appropriate lighting conditions which minimize glare. B) Take a minimum of 24 microscopic in-focus images of the exterior, lip, walls, and interior of the specimen under appropriate lighting conditions. C) NASA, and the rover team must make public and supply Petitioner with all high resolution photos and images of that specimen as demanded in A and B. Enjoy the full suit embedded below: http://www.popsci.com/article/scienc...src=SOC&dom=fb
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01-29-2014, 07:03 PM | #1284 |
Seize life. Be an ermine.
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I kind of want to plant a gympie gympie plant next to the sidewalk in my front yard. I wonder if they would grow here.
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01-30-2014, 12:45 AM | #1285 | |
Deus ambulans inter homines
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2nd Note to Self: Send gift baskets with said plant to the entire Broncos organization, roster, and coaches with a tiny gift message stating these are a rare and exotic Asian plant that has been known to bestow luck and divine fortune. Stating for all who have rubbed the leaf on their hands, feet, and forehead to signify being 1 with the all the major elements as well as the mind, and then ingesting 1 of the leaves as a sign of being consumed by your mission and drive to victory.
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01-30-2014, 01:20 AM | #1286 | |
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FYP... |
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01-30-2014, 08:25 PM | #1287 | ||
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Of course... just dip the cells in acid. Why wasn't that the first thing we tried?
Stem cell breakthrough could be a game changer for personalized medicine One of the biggest drawbacks to stem cells is that creating them is a bit of a process. There is so much potential to solve a variety of physical ailments with stem cells, but it is not yet a simple, practical solution. However, a new method generates stem cells faster and cheaper than normal and could revolutionize personal medicine. The results come from Haruko Obokata from Japan’s Riken Center for Developmental Biology and were published in Nature. When the body is developing, certain cells have the ability to be stimulated into differentiating into a number of different cells. While these are abundant in embryos and umbilical cords, they are more rare in adults. A great deal of research has gone into transforming differentiated cells back into their stem cell state, known as induced pluripotent stem cells. There has been considerable success on this front, but it takes many months to complete and is a fairly expensive process. In this new technique, blood cells are exposed to acid, which shocks them back to their stem cell state. Obokata’s method is so easy, some researchers did not believe her results. In fact, there was such a lack of support, she nearly abandoned her project. Luckily, she stuck with it and developmental biologists herald the technique as “remarkable” and “a game changer” for personalized medicine that eliminates rejection, because they already come from each patient’s body. So far, the technique has only been demonstrated with mouse blood. Future trials will explore how the method works with human blood. If all goes well and the technology works well on human cells, this could represent a new source of cells that can be used in regenerative applications following trauma and also in treatment of diseases like Parkinson’s disease and cancer. They could also be used to generate replacement organs, which would alleviate much of the strain on the organ donation wait list. There is still a large amount of research to be done with using stem cells as an effective treatment, and Dr. Obokata’s induction method will not change that. Also, it remains to be seen how the low pH affects the integrity of the cells as they differentiate into bone, skin, nerve, and muscle cells. However, creating a cheaper, more efficient means of creating the stem cells could expedite some aspects of that research and help pave the way for stem cells to become a mainstream method of individualized treatment. UPDATE: Quote:
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01-30-2014, 08:30 PM | #1288 |
Ain't no relax!
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Fun Science projects to do with the kids!
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01-30-2014, 10:22 PM | #1289 |
On the inside
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A Gympie Gympie tree, VX poison gas, and a black widow all walk into a bar...
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01-30-2014, 10:26 PM | #1290 |
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How much would it take for you to use a condom made entirely out of gympie gympie leaves?
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