A Northwestern University research team has found a way to manufacture single laser devices that are the size of a virus particle and that operate at room temperature. These plasmonic nanolasers could be readily integrated into silicon-based photonic devices, all-optical circuits and nanoscale biosensors. Reducing the size of photonic and electronic elements is critical for ultra-fast data processing and ultra-dense information storage. The miniaturization of a key, workhorse instrument -- the laser -- is no exception.
Soybean (Glycine max (L.) Merr.) is an important crop that provides a sustainable source of protein and oil worldwide. Soybean cyst nematode (Heterodera glycines Ichinohe) is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone1, making it the most economically important pathogen on soybean. Although planting of resistant cultivars forms the core management strategy for this pathogen, nothing is known about the nature of resistance. Moreover, the increase in virulent populations of this parasite on most known resistance sources necessitates the development of novel approaches for control. Here we report the map-based cloning of a gene at the Rhg4 (for resistance to Heterodera glycines 4) locus, a major quantitative trait locus contributing to resistance to this pathogen. Mutation analysis, gene silencing and transgenic complementation confirm that the gene confers resistance. The gene encodes a serine hydroxymethyltransferase, an enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Alleles of Rhg4 conferring resistance or susceptibility differ by two genetic polymorphisms that alter a key regulatory property of the enzyme. Our discovery reveals an unprecedented plant resistance mechanism against a pathogen. The mechanistic knowledge of the resistance gene can be readily exploited to improve nematode resistance of soybean, an increasingly important global crop.
Retiree Walter R. Tschinkel is an entomologist and former professor of Biological Science at Florida State University. He recognizes ants as "some of nature's grand architects" and, curious to understand their self-created habitats, devised a clever (if cruel) way to do it: By pouring molten aluminum down into the hole.
Unsurprisingly, the ants die in the process. But after the aluminum cools and Tschinkel has completed a meticulous excavation, he unearths these wondrous, chandelier-esque shapes revealing the alien architectures of the colony.
Biomarkers predicting metastatic capacity might assist the development of better therapeutic strategies for aggressive cancers such as lung cancer. A new study showed that adenylate kinase-4 (AK4) is a progression-associated gene in human lung cancer that promotes metastasis. AK4 is upregulated in lung adenocarcinoma compared with normal cells. High AK4 expression was associated with advanced stage, disease recurrence and poor prognosis.
Plants and pathogens evolve in response to each other. This co-evolutionary arms race is fueled by genetic variation underlying the recognition of pathogen proteins by the host and the defeat of host defenses by the pathogen. Together with new mutations, genetic diversity in populations of both the host and pathogen represent a pool of possible variants to maintain adaptation via natural selection.Drastic changes in genetic diversity in crop species have occurred as a consequence of domestication. Whether changes in the genetic composition of these host populations also have affected genetic diversity in pathogen species is, so far, poorly understood. Advances in comparative genomics and population genomic approaches open new avenues to study adaptive processes in plant pathogens and to infer the impact of agro-ecosystems on the evolution of pathogen populations. Here we summarize new insights gained from comparative genome studies and population genomics in host-pathogen systems.
Biology: Changing the world inspiring and celebrating the great biologists of the UK - a new project by the Society of Biology, Heritage Lottery Fund and BBSRC.
Biology: Changing the World will celebrate life science research and life scientists, communicating their discoveries to students and teachers. The project focusses on how biology has saved the world, from discoveries that have changed how we treat a disease to scientists that have campaigned to save a species on the bridge of extinction. Sharing the journey of the individual; how they became a biologist and the hurdles they overcame will be a crucial part of our project." .
(Source: Northampton Borough Council) Published Monday, 31 December 2012 Northampton Borough Council is reminding those that usually have their black bins, (http://t.co/QF91oDnm Making recycling your...
The eukaryotic microbes known as oomycetes are common inhabitants of terrestrial and aquatic environments and include saprophytes and pathogens. Lifestyles of the pathogens extend from biotrophy to necrotrophy, obligate to facultative pathogenesis, and narrow to broad host ranges on plants or animals. Sequencing of several pathogens has revealed striking variation in genome size and content, a plastic set of genes related to pathogenesis, and adaptations associated with obligate biotrophy. Features of genome evolution include repeat-driven expansions, deletions, gene fusions, and horizontal gene transfer in a landscape organized into gene-dense and gene-sparse sectors and influenced by transposable elements. Gene expression profiles are also highly dynamic throughout oomycete life cycles, with transcriptional polymorphisms as well as differences in protein sequence contributing to variation. The genome projects have set the foundation for functional studies and should spur the sequencing of additional species, including more diverse pathogens and nonpathogens.
During the several billions of years since life began on this planet, some organisms gained the capacity for multicellularity — the ability to make multiple cells and multiple cell types. How does multicellularity evolve?
Life is very good at reinventing itself over time, and one of its most important innovations has been multicellularity, the capacity to make multiple cells and cell types that carry out specialized functions. Without the evolution of multicellularity, our planet would be a very different place — a world without plants or animals of any kind, and of course without humans. Yet even though multicellular species have evolved independently in most major lineages of eukaryotic organisms — including not only those to which plants and animals belong, but also green algae, brown algae, red algae, ciliates, slime molds, and fungi — we know surprisingly little about how this evolution came about. Do certain properties predispose a unicellular lineage to make the leap to multicellularity? Are certain types of genes/gene families, or genetic mechanisms especially important for this sort of transition to occur? Does the evolution of multicellularity require big steps involving major increases in genome size and/or expansions in gene families, or even many new kinds of genes? Or might the transition to a multicellular form possibly take place in smaller steps, involving only subtle changes? Scientists who study a family of green algae that includes unicellular Chlamydomonas and multicellular Volvox are beginning to find answers to some of these questions.
The most precise measurement ever made of the speed of the universe's expansion is in, thanks to NASA's Spitzer Space Telescope, and it's a doozy. Space itself is pulling apart at the seams, expanding at a rate of 74.3 plus or minus 2.1 kilometers (46.2 plus or minus 1.3 miles) per second per megaparsec (a megaparsec is roughly 3 million light-years).
American astronomer Edwin P. Hubble first discovered that our universe isn't static in the 1920s. In fact, Hubble found, space has been expanding since it began with the Big Bang 13.7 billion years ago. Then, in the 1990s, astronomers shocked the world again with the revelation that this expansion is speeding up (this discovery won its finders the 2011 Nobel Prize in physics).
Ever since Hubble's initial discovery, scientists have been trying to refine their measurement of the universe's expansion rate, called the Hubble Constant. It's a hard measurement to make. The new value reduces the uncertainty in the Hubble Constant to just 3 percent, and improves the precision of the measurement by a factor of 3 compared to a previous estimate from the Hubble Space Telescope.
"Just over a decade ago, using the words 'precision' and 'cosmology' in the same sentence was not possible, and the size and age of the universe was not known to better than a factor of two," Wendy Freedman of the Observatories of the Carnegie Institution for Science in Pasadena, Calif., said in a statement. "Now we are talking about accuracies of a few percent. It is quite extraordinary."
I just saw this editorial from last year by David Botstein, in which he talks about how important it is for researchers to teach. (http://ascb.org/files/1111Presidents.pdf). In addition to an interesting history of the research / teaching dichotomy, he says,
"The intellectual effort that serious teaching requires is, in my experience, amply repaid in enhanced intellectual breadth, mental sophistication, and clarity of scientific vision."
If you are talking with your students about publications, they may find this site interesting. It's a set of donated rejection letters received by scientists. It's a nice idea to share and maybe destigmatize the pain of rejection, so that when students get their first one they'll realize that all is not lost. The site is here (http://emlab.rose2.brandeis.edu/rejections). "Rather than hiding these low points in the trajectory of a scientific paper, this forum offers a place to publish these letters and comments to educate others."