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Archive - Jan 13, 2017

Arabica Coffee Genome Sequenced

The first public genome sequence for Coffea arabica, the species responsible for more than 70 percent of global coffee production, was released today by researchers at the University of California (UC) Davis. Funding for the sequencing was provided by Suntory group, an international food and beverage company based in Tokyo. Now available for immediate use by scientists and plant breeders around the world, the new genome sequence has been posted to, the public database for comparative plant genomics coordinated by the U.S. Department of Energy's Joint Genome Institute (JGI). Details of the sequence will be presented Sunday, January 15, 2017 at the Plant and Animal Genome Conference in San Diego. Sequencing of the C. arabica genome is particularly meaningful for California, where coffee plants are being grown commercially for the first time in the continental United States and a specialty-coffee industry is emerging. "This new genome sequence for Coffea arabica contains information crucial for developing high-quality, disease-resistant coffee varieties that can adapt to the climate changes that are expected to threaten global coffee production in the next 30 years," said Juan Medrano, Ph.D., a geneticist in the UC Davis College of Agricultural and Environmental Sciences and co-researcher on the sequencing effort. "We hope that the C. arabica sequence will eventually benefit everyone involved with coffee -- from coffee farmers, whose livelihoods are threatened by devastating diseases like coffee leaf rust, to coffee processors and consumers around the world," he said. The sequencing was conducted through a collaboration among Dr. Medrano, plant scientists Dr. Allen Van Deynze and Dr. Dario Cantu, and postdoctoral research scholar Dr. Amanda Hulse-Kemp, all from UC Davis.

Nuclear Localization of Mitochondrial TCA Cycle Enzymes Is Critical to Genome Activation in Mammalian Zygotes

To turn on its genome — the full set of genes inherited from each parent — a mammalian embryo needs to relocate a group of proteins, researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA have discovered. The metabolic proteins, normally found in the energy-generating mitochondria of cells, move to the DNA-containing nuclei about two days after a mouse embryo is fertilized, according to the new study, led by senior author Dr. Utpal Banerjee. The study was published in the January 12, 2017 issue of Cell and is titled “Nuclear Localization of Mitochondrial TCA Cycle Enzymes As a Critical Step in Mammalian Zygotic Genome Activation.” Early in development, a mammalian embryo — or zygote — has all the materials it needs to grow and divide from genes and proteins that were contained in the egg cell. But after a few cell divisions, the zygote needs to activate its own genome. Researchers have never fully understood how this shift is made. They knew that certain metabolic compounds, such a pyruvate, were required, but had also observed that the mitochondria — which normally process pyruvate into energy — were small and inactive during this stage of development. Dr. Banerjee, a Professor of Molecular, Cell, and Developmental Biology and Co-Director of the UCLA Broad Stem Cell Research Center, and colleagues confirmed that pyruvate was required for zygotes to activate their genomes by growing mouse zygotes in a culture dish lacking pyruvate. Then, in both mouse and human embryos, researchers used a number of methods to determine the location of proteins that process pyruvate through a metabolic program called the tricarboxylic acid (TCA) cycle.

New Model Could Help Scientists Design Materials for Artificial Photosysnthesis

Plants and other photosynthetic organisms use a wide variety of pigments to absorb different wavelengths of light. MIT researchers have now developed a theoretical model to predict the spectrum of light absorbed by aggregates of these pigments, based on their structure. The new model could help guide scientists in designing new types of solar cells made of organic materials that efficiently capture light and funnel the light-induced excitation, according to the researchers. “Understanding the sensitive interplay between the self-assembled pigment superstructure and its electronic, optical, and transport properties is highly desirable for the synthesis of new materials and the design and operation of organic-based devices,” says Dr. Aurelia Chenu, an MIT postdoc and the lead author of the study, which appeared in Physical Review Letters on January 3, 2017. The article is titled “Construction of Multichromophoric Spectra from Monomer Data: Applications to Resonant Energy Transfer.” Photosynthesis, performed by all plants and algae, as well as some types of bacteria, allows organisms to harness energy from sunlight to build sugars and starches. Key to this process is the capture of single photons of light by photosynthetic pigments, and the subsequent transfer of the excitation to the reaction centers, the starting point of chemical conversion. Chlorophyll, which absorbs blue and red light, is the best-known example of photosynthetic pigments, but there are many more, such as carotenoids, which absorb blue and green light, as well as others specialized to capture the scarce light available deep in the ocean.

Congenital Tremor of “Shaking Pigliets” Caused by Newly Identified Virus

Cases of newborn "shaking piglets" have been reported since the 1920s both in Europe and abroad. Yet the cause for these congenital tremors has so far eluded researchers. A previously unknown virus had been suspected for quite some time - but without conclusive confirmation. On the basis of new genomic sequence data, a team of researchers from the University Clinic for Swine, the Institute of Virology, and the Institute of Pathology and Forensic Veterinary Medicine at Vetmeduni Vienna has now been able to identify a new virus as the cause of this potentially life-threatening disease. The pathogen, which belongs to the family of so-called atypical porcine pestiviruses (APPV), was detected in diseased animals at Austrian farms using a specially developed test. "Depending on the severity of the shaking, congenital tremor presents a challenge for the piglets from the first minute of their life," says first author Dr. Lukas Schwarz, veterinary clinician at the University Clinic for Swine. The tremor can sometimes be so severe that the piglet is unable to properly suckle milk. Yet suckling is especially important for piglets in the first 24 hours after birth. Only mother's milk contains everything the animals need to survive. "Without the first drink of mother's milk, piglets have a very low chance of survival," Dr. Schwarz explains. In piglets that survive this first phase, symptoms usually subside after three or four weeks. In rare cases, a slight tremor remains in the ears. But getting this far requires an enormous amount of attention and care on the part of the pig farmers and veterinarians. This makes it even more surprising that researchers have so far failed to identify a cause for this mysterious disease.