Scientists extracted DNA from spider webs to identify the web's spider architect and the prey that crossed it, according to this proof-of-concept study published on November 25, 2015 in the open-access journal PLOS ONE by Charles C. Y. Xu from the University of Notre Dame, and colleagues. The article is titled “Spider Web DNA: A New Spin on Noninvasive Genetics of Predator and Prey.” Noninvasive genetic sampling enables biomonitoring without the need to directly observe or disturb target organisms. The authors of this study used three black widow spiders fed house crickets to noninvasively extract, amplify, and sequence mitochondrial DNA from their spider web samples, which identified both the spider and its prey to the species level. The detectability of spider DNA did not differ between assays and spider and prey DNA remained detectable at least 88 days after living organisms were no longer present on the web. The authors suggest that these results may encourage further studies that could lead to practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments. However, further testing of field-collected spider webs from more species and habitats is needed to evaluate the generality of these findings. Xu says: "Sticky spider webs are natural DNA samplers, trapping nearby insects and other things blowing in the wind. We see potential for broad environmental monitoring because spiders build webs in so many places." The image shows a Southern black widow spider (Latrodectus mactans) with its prey house cricket (Acheta domesticus) trapped in spider web. (Credit: Scott Camazine).
Using the ground-breaking CRISPR/Cas9 gene editing technique, University of California scientists have created a strain of mosquitoes capable of rapidly introducing malaria-blocking genes into a mosquito population through its progeny, ultimately eliminating the insects' ability to transmit the disease to humans. This new model represents a notable advance in the effort to establish an anti-malarial mosquito population, which with further development could help eradicate a disease that sickens millions worldwide each year. To create this breed, researchers at the Irvine and San Diego campuses inserted a DNA element into the germ line of Anopheles stephensi mosquitoes that resulted in the genes preventing malaria transmission being passed on to an astonishing 99.5 percent of offspring. The transferred genes included dual anti-Plasmodium falciparum effector genes, a marker gene, and the autonomous gene-drive components. A. stephensi is a leading malaria vector in Asia. The study underlines the growing utility of the CRISPR method, a powerful gene editing tool that allows access to a cell's nucleus to snip DNA to either replace mutated genes or insert new ones. Results were published online on November 23, 2015 in PNAS. The article is titled “Highly Efficient Cas9-Mediated Gene Drive for Population Modification of the Malaria Vector Mosquito Anopheles stephensi.” "This opens up the real promise that this technique can be adapted for eliminating malaria," said Anthony James, Ph.D., Distinguished Professor of Molecular Biology & Biochemistry and Microbiology & Molecular Genetics at UC Irvine (UCI). For nearly 20 years, the James lab has focused on engineering anti-disease mosquitoes.
Swimming in a pool of syrup would be difficult for most people, but for bacteria like E. coli, it's easier than swimming in water. Scientists have known for decades that these cells move faster and farther in viscoelastic fluids, such as the saliva, mucus, and other bodily fluids they are likely to call home, but didn't understand why. Now, researchers from the University of Pennsylvania (Penn) School of Engineering and Applied Science and the Penn School of Arts & Sciences have come together to find an answer. Their findings could inform disease models and treatments, or even help design microscopic swimming robots. The study was led by Paulo Arratia, Ph.D., an Associate Professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering, and lab member Alison Patteson, a graduate student. Postdoctoral researcher Arvind Gopinath, Ph.D., a member of the Arratia lab, and Mark Goulian, Ph.D., the Edmund J. and Louise W. Kahn Endowed Term Professor of Biology in Penn Arts & Sciences, contributed to the study, which was published online on October 28, 2015 in an open-access article in Scientific Reports. The article is titled “Running and Tumbling with E. coli in Polymeric Solutions.” Experiments in the 1970s showed that, when in water, E. coli demonstrated what is known as "run and tumble" swimming. A bacterium would swim in a straight line, then tumble, or change direction in a random way. This is a good strategy for finding food, but it was unclear how that strategy would change in the more gelatinous fluids that E. coli tend to live in. "What's different now is that we can characterize the material properties of these fluids more precisely," Patteson said, "so we can connect changes in those properties to changes in the swimming behavior of the cells in a very systematic way.
The mosquito-borne virus Chikungunya may lead to severe brain infection and even death in infants and people over 65, according to a new study that reviewed a Chikungunya outbreak on Reunion Island off the coast of Madagascar in 2005-2006. The study was published online today (November 25, 2015) in Neurology, the medical journal of the American Academy of Neurology. The article is titled “Chikungunya Virus–Associated Encephalitis: A Cohort Study on La Réunion Island, 2005–2009.” Many cases have occurred in the United States in people who acquired the virus while traveling, but the first locally transmitted case in the U.S. occurred in Florida in July 2015. The Neurology-published study showed that the rate of brain infection, or encephalitis, from the Chikungunya virus is higher than the rate seen in the United States due to West Nile virus and similar infections between 1999 and 2007. Outbreaks of Chikungunya have occurred in numerous areas, including Africa, Asia, the Caribbean islands, and, as of September 2015, more than 7,000 cases have been reported in Mexico, according to the Centers for Disease Control and Prevention (CDC). The most common symptoms of the infection are fever and joint pain. Most people recover within a week. For some people, however, the joint pain can continue for months and even years. "Because there is no vaccine to prevent Chikungunya and no medicine to treat it, people who are traveling to these areas should be aware of this infection and take steps to avoid mosquito bites, such as wearing repellent and long-sleeves and pants if possible," said study lead author Patrick Gérardin, M.D., Ph.D., of Central University Hospital in Saint Pierre, Reunion Island. The epidemic of the virus on Reunion Island occurred in 2005 to 2006 and affected 300,000 people.
Gene duplications are a common cause of intellectual disabilities and autism, as well as various other neurological disorders. In a new study that was published online today (November 25, 2015) in Nature, Huda Zoghbi (photo), M.D., Professor of Molecular and Human Genetics at Baylor College of Medicine, and Director of the Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, and her team showed that there is a new potential way to treat such disorders. MECP2 (methyl-CpG-binding) protein is a cellular maestro, that modulates the expression of thousands of genes in the brain, but its levels must be carefully controlled. Too little of the protein results in Rett syndrome, a childhood neurological disorder characterized by decreased cognition, inability to perform motor functions, particularly with hands, and autism-like behavior. More than 10 years ago, Dr. Zoghbi who is also a Howard Hughes Medical Institute (HHMI) investigator, discovered that MECP2 is a "Goldilocks" protein - too little causes Rett syndrome, but too much can cause a different neurological problem. The mouse models that Zoghbi's lab generated with an extra copy of the MECP2 gene developed a progressive neurological disorder. Dr. Zoghbi suspected there must be children or adults with analogous neurological problems due to duplication of the MECP2 gene and this proved to be the case. Boys with the MECP2 duplication syndrome suffer from poor muscle tone and motor function, cognitive disability, epilepsy, autistic behaviors, respiratory infections, and premature death. Once considered rare, it appears that MECP2 duplication syndrome is more common than previously thought, said Yehezkel Sztainberg, Ph.D., a postdoctoral fellow in Zoghbi's laboratory and first author of the report.
What doesn't kill you could cure you. A growing interest in the therapeutic value of animal venom has led a pair of Columbia University data scientists to create the first catalog of known animal toxins and their physiological effects on humans. VenomKB, short for Venom Knowledge Base, summarizes the results of 5,117 studies in the medical literature describing the use of venom toxins as painkillers and as treatments for diseases like cancer, diabetes, obesity, and heart failure. Drawn from an automated analysis of the literature, VenomKB documents nearly 42,723 effects on the body. Though modern medicine makes use of only a small fraction of the toxins documented thus far, the researchers hope that the catalog will spur the discovery of new compounds and medical treatments. "With this list, we can take stock of what we know about venoms and their therapeutic effects" said Nicholas Tatonetti, Ph.D., an Assistant Professor of Biomedical Informatics at Columbia University Medical Center and a member of the Data Science Institute. "The questions now is: How can we use this information with other databases to discover new compounds and therapies?" Dr. Tatonetti and Joseph Romano, a graduate student, searched on the term "venoms/therapeutic use" in a database of 22 million medical research papers. This produced a list of 5,117 venom-related studies whose results they summarized using a pair of computer algorithms. After cross-referencing toxins and drugs listed under multiple names and correcting other irregularities in the data, they found 42,723 unique mentions of venoms having a specific effect on the body. Their results were published online on November 24, 2015 in a companion study (open-access) to Venom KB in the journal Scientific Data.
A latticework of tiny tubes called microtubules gives your cells their shape and also acts like a railroad track that essential proteins travel on. But if there is a glitch in the connection between train and track, diseases can occur. In the November 24, 2015 issue of PNAS, Tatyana Polenova, Ph.D., Professor of Chemistry and Biochemistry, and her team at the University of Delaware (UD), together with John C. Williams, Ph.D., Associate Professor at the Beckman Research Institute of City of Hope in Duarte, California, reveal for the first time -- atom by atom -- the structure of a protein bound to a microtubule. The protein of focus, CAP-Gly, short for "cytoskeleton-associated protein-glycine-rich domains," is a component of dynactin, which binds with the motor protein dynein to move cargoes of essential proteins along the microtubule tracks. Mutations in CAP-Gly have been linked to such neurological diseases and disorders as Perry syndrome and distal spinal bulbar muscular dystrophy. The research team used magic-angle-spinning nuclear magnetic resonance spectrometry (NMR) in the Department of Chemistry and Biochemistry at UD to unveil the structure of the CAP-Gly protein assembled on polymerized microtubules. The CAP-Gly protein has 1,329 atoms, and each tubulin dimer, which is a building block for microtubules, has nearly 14,000 atoms. "This is the first time anyone has been able to get an atomic-resolution structure of any microtubule-associated protein assembled on polymerized microtubules," Dr. Polenova says.
Many birds travel in flocks, sometimes migrating over thousands of miles. But how do the birds decide who will lead the way? Researchers reporting in the Cell Press journal Current Biology on November 25, 2015, now have some new insight based on studies in homing pigeons. For pigeons, it seems, leadership is largely a question of speed. The article is titled “Speed Determines Leadership and Leadership Determines Learning During Pigeon Flocking." "This changes our understanding of how the flocks are structured and why flocks of this species have consistent leadership hierarchies," says Dora Biro, Ph.D., of the University of Oxford. Previous studies had shown that flock leadership is unrelated to social dominance. Giving followers extra training flights doesn't promote them to a position of leadership, either. The new findings offer an elegantly simple explanation for the phenomenon of leadership in birds, with important implications for how spatial knowledge is generated and retained in navigating flocks. While many birds travel in flocks, homing pigeons are domestic and more easily studied than most. "We can control the composition of the flocks and the starting points for their homeward journeys," says Benjamin Pettit, Ph.D., the first author of the new study. "We also have a good understanding of their individual spatial cognition, in particular how their homing routes develop over repeated flights in the same area." Recent developments in sensor technology also make it possible to explore, with exquisite precision, how pigeon flocks are coordinated. The latest GPS loggers allow the researchers to track not only the birds' overall routes, but also the sub-second time delays with which they react to each other while flying as a flock.
Drowning has emerged as a mysterious cause of death amongst groups of young common starlings (Sturnus vulgaris), according to research by a team of scientists led by international conservation charity the Zoological Society of London (ZSL). Drowning as a cause of death amongst wild birds is comparatively rare and normally involves single rather than multiple animals. Starlings, however, have been observed to drown in groups of 10 or more, prompting scientists to investigate these unusual occurrences. The research team studied 12 separate incidents of starling drownings recorded between 1993 and 2013, finding that on 10 of these occasions, more than 10 birds drowned. All of these incidents, which usually involved juvenile birds just a few months old, occurred during the spring and early summer months. In all cases, scientists found no evidence of underlying disease as a cause of death. Dr. Becki Lawson, lead author and wildlife veterinarian at ZSL, commented: "Drowning appears to be a more common cause of death amongst younger birds, as they may be inexperienced in identifying water hazards. This combined with the fact that starlings are a highly social species could potentially explain why multiple birds drown together. Members of the public from around Great Britain have been instrumental in bringing this unexpected cause of starling mortality to our attention by reporting these incidents. With starling numbers declining in general across the UK, we need to learn more about how and where these phenomena happen, in order to better understand why," Dr. Lawson explained. The research was published online on November 25, 2015 in an open-access article in Scientific Reports.
Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen Research & Development, LLC. The findings, which were published online on November 25, 2015 in the Journal of Neuroscience, implicate one family of molecules in particular -- thrombospondins -- that may have therapeutic potential for the treatment of degenerative eye diseases. The article is titled “Human Umbilical Tissue-Derived Cells (hUTC) Promote Synapse Formation and Neurite Outgrowth via Thrombospondin Family Proteins.” "By learning more about how these cells work, we are one step closer to understanding the disease states in which these cells should be studied," said Cagla Eroglu (photo), Ph.D., an Assistant Professor of Cell Biology and Neurobiology at the Duke University Medical Center, who led the research. Umbilical cord tissue-derived cells (hUTC) differ from umbilical cord blood cells in that they are isolated from cord tissue itself, rather than the blood. The Duke team used an established cell culture system to determine whether and how the hUTCs might affect the growth of neurons isolated from the retinas of rat eyes. In an experimental setup that allowed the two types of cells to bathe in the same fluid without coming into physical contact, retinal neurons in a bath with hUTCs formed new synaptic connections between neurons, and they sprouted new 'neurites' -- tiny branches that lead to additional connections. These cells also survived longer than rat neurons placed in a bath lacking the umbilical cord tissue-derived cells. Something present in the fluid surrounding the neurons in the bath with the hUTCs was apparently affecting the neurons.