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41.
Laura Greenwood Lucinda Lawson Eli Greenbaum Breda M. Zimkus 《Journal of Natural History》2020,54(1-4):63-85
ABSTRACT Using integrative approaches, a new large-bodied species of Phrynobatrachus is described from a series of 48 specimens from the montane forests of the West Usambara and North Pare Mountains of Tanzania. The most distinguishing morphological feature separating Phrynobatrachus ambanguluensis sp. nov from similar species is the markedly overhanging and pointed upper jaw and snout. Mitochondrial 16S rRNA indicates that the new species differs from all other species with published sequence data by a minimum distance of 4.75% and is sister to P. krefftii, with which it has been confused in the past. The new species is known from two forest reserves and is of high conservation concern given these areas are highly impacted by anthropogenic change. http://www.zoobank.org/urn:lsid:zoobank.org:pub:E0C82A87-47A5-426B-978D-96D27FA7A3B7 相似文献
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Genome-wide DNA rearrangements occur in many eukaryotes but are most exaggerated in ciliates, making them ideal model systems for epigenetic phenomena. During development of the somatic macronucleus, Oxytricha trifallax destroys 95% of its germ line, severely fragmenting its chromosomes, and then unscrambles hundreds of thousands of remaining fragments by permutation or inversion. Here we demonstrate that DNA or RNA templates can orchestrate these genome rearrangements in Oxytricha, supporting an epigenetic model for sequence-dependent comparison between germline and somatic genomes. A complete RNA cache of the maternal somatic genome may be available at a specific stage during development to provide a template for correct and precise DNA rearrangement. We show the existence of maternal RNA templates that could guide DNA assembly, and that disruption of specific RNA molecules disables rearrangement of the corresponding gene. Injection of artificial templates reprogrammes the DNA rearrangement pathway, suggesting that RNA molecules guide genome rearrangement. 相似文献
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The ground state of embryonic stem cell self-renewal 总被引:3,自引:0,他引:3
Ying QL Wray J Nichols J Batlle-Morera L Doble B Woodgett J Cohen P Smith A 《Nature》2008,453(7194):519-523
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Therapies for patients with cancer have changed gradually over the past decade, moving away from the administration of broadly acting cytotoxic drugs towards the use of more-specific therapies that are targeted to each tumour. To facilitate this shift, tests need to be developed to identify those individuals who require therapy and those who are most likely to benefit from certain therapies. In particular, tests that predict the clinical outcome for patients on the basis of the genes expressed by their tumours are likely to increasingly affect patient management, heralding a new era of personalized medicine. 相似文献
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Laura Pecci S. Duprè A. Antonucci D. Cavallini 《Cellular and molecular life sciences : CMLS》1980,36(8):910-911
Summary Pyridoxal-5-phosphate (PLP) reacts with -carboxyglutamic acid (Gla) to form a stable complex absorbing at 325 nm. It is suggested that a condensation occurs in which the formyl group of PLP reacts with the -amino group and the carbon atom of Gla to give a pyrrolidine derivative. 相似文献
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Daffonchio D Borin S Brusa T Brusetti L van der Wielen PW Bolhuis H Yakimov MM D'Auria G Giuliano L Marty D Tamburini C McGenity TJ Hallsworth JE Sass AM Timmis KN Tselepides A de Lange GJ Hübner A Thomson J Varnavas SP Gasparoni F Gerber HW Malinverno E Corselli C Garcin J McKew B Golyshin PN Lampadariou N Polymenakou P Calore D Cenedese S Zanon F Hoog S;Biodeep Scientific Party 《Nature》2006,440(7081):203-207
The chemical composition of the Bannock basin has been studied in some detail. We recently showed that unusual microbial populations, including a new division of Archaea (MSBL1), inhabit the NaCl-rich hypersaline brine. High salinities tend to reduce biodiversity, but when brines come into contact with fresher water the natural haloclines formed frequently contain gradients of other chemicals, including permutations of electron donors and acceptors, that may enhance microbial diversity, activity and biogeochemical cycling. Here we report a 2.5-m-thick chemocline with a steep NaCl gradient at 3.3 km within the water column betweeen Bannock anoxic hypersaline brine and overlying sea water. The chemocline supports some of the most biomass-rich and active microbial communities in the deep sea, dominated by Bacteria rather than Archaea, and including four major new divisions of Bacteria. Significantly higher metabolic activities were measured in the chemocline than in the overlying sea water and underlying brine; functional analyses indicate that a range of biological processes is likely to occur in the chemocline. Many prokaryotic taxa, including the phylogenetically new groups, were confined to defined salinities, and collectively formed a diverse, sharply stratified, deep-sea ecosystem with sufficient biomass to potentially contribute to organic geological deposits. 相似文献
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