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991.
Description of diatoms from the Southwest to West Greenland coastal and open marine waters 总被引:1,自引:0,他引:1
Diana W. Krawczyk Andrzej Witkowski Joanna J. Waniek Marcin Wroniecki Jan Harff 《Polar Biology》2014,37(11):1589-1606
Detailed studies on sub-Arctic and Arctic marine diatom assemblages contribute to the understanding of spatial distribution patterns and their physical drivers. In this study, diatom species were analyzed from water samples collected with a Niskin bottle rosette combined with a CTD along the West Greenland coast (63°58′N–71°08′N and 50°49′W–59°06′W) during summer 2007. Diatom community was represented mainly by three genera Thalassiosira, Fragilariopsis, and Chaetoceros and linked to observed hydrographic and environmental conditions. Thalassiosira spp. were common in coastal waters (particularly Godthåbsfjord) and linked to increased surface water temperature, typical of summer water stratification in West Greenland. Fragilariopsis spp., along with other dominant species associated with higher geographic latitudes, dominated in Arctic fjords (Uummannaq Fjord-Qaumarujuk Fjord). These species generally characterized coastal waters influenced by melting sea ice and/or glacial ice. Chaetoceros spp. were linked to more saline open marine waters, particularly in the Davis Strait south of 70°N, probably corresponding to weaker water stratification and the influence of the West Greenland Current. The present paper provides new knowledge on diatom assemblages along a south–north climate gradient in West Greenland, which is necessary in order to understand how observed ocean-climate changes influence Arctic marine ecosystems. This study provides a reference for palaeoenvironmental reconstructions using diatom microfossils deposited in the West Greenland marine sediments. 相似文献
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Silke Roedder Tara Sigdel Nathan Salomonis Sue Hsieh Hong Dai Oriol Bestard Diana Metes Andrea Zeevi Albin Gritsch Jennifer Cheeseman Camila Macedo Ram Peddy Mara Medeiros Flavio Vincenti Nancy Asher Oscar Salvatierra Ron Shapiro Allan Kirk Elaine Reed Minnie M. Sarwal 《PLoS medicine》2014,11(11)
BackgroundDevelopment of noninvasive molecular assays to improve disease diagnosis and patient monitoring is a critical need. In renal transplantation, acute rejection (AR) increases the risk for chronic graft injury and failure. Noninvasive diagnostic assays to improve current late and nonspecific diagnosis of rejection are needed. We sought to develop a test using a simple blood gene expression assay to detect patients at high risk for AR.ConclusionsThe kSORT blood QPCR assay is a noninvasive tool to detect high risk of AR of renal transplants.Please see later in the article for the Editors'' Summary 相似文献
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Lubov Petkova Nedialkova Rémy Denzler Martin B. Koeppel Manuel Diehl Diana Ring Thorsten Wille Roman G. Gerlach B?rbel Stecher 《PLoS pathogens》2014,10(1)
The host''s immune system plays a key role in modulating growth of pathogens and the intestinal microbiota in the gut. In particular, inflammatory bowel disorders and pathogen infections induce shifts of the resident commensal microbiota which can result in overgrowth of Enterobacteriaceae (“inflammation-inflicted blooms”). Here, we investigated competition of the human pathogenic Salmonella enterica serovar Typhimurium strain SL1344 (S. Tm) and commensal E. coli in inflammation-inflicted blooms. S. Tm produces colicin Ib (ColIb), which is a narrow-spectrum protein toxin active against related Enterobacteriaceae. Production of ColIb conferred a competitive advantage to S. Tm over sensitive E. coli strains in the inflamed gut. In contrast, an avirulent S. Tm mutant strain defective in triggering gut inflammation did not benefit from ColIb. Expression of ColIb (cib) is regulated by iron limitation and the SOS response. CirA, the cognate outer membrane receptor of ColIb on colicin-sensitive E. coli, is induced upon iron limitation. We demonstrate that growth in inflammation-induced blooms favours expression of both S. Tm ColIb and the receptor CirA, thereby fuelling ColIb dependent competition of S. Tm and commensal E. coli in the gut. In conclusion, this study uncovers a so-far unappreciated role of inflammation-inflicted blooms as an environment favouring ColIb-dependent competition of pathogenic and commensal representatives of the Enterobacteriaceae family. 相似文献
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Diana Clausznitzer Gabriele Micali Silke Neumann Victor Sourjik Robert G. Endres 《PLoS computational biology》2014,10(10)
Sensory systems have evolved to respond to input stimuli of certain statistical properties, and to reliably transmit this information through biochemical pathways. Hence, for an experimentally well-characterized sensory system, one ought to be able to extract valuable information about the statistics of the stimuli. Based on dose-response curves from in vivo fluorescence resonance energy transfer (FRET) experiments of the bacterial chemotaxis sensory system, we predict the chemical gradients chemotactic Escherichia coli cells typically encounter in their natural environment. To predict average gradients cells experience, we revaluate the phenomenological Weber''s law and its generalizations to the Weber-Fechner law and fold-change detection. To obtain full distributions of gradients we use information theory and simulations, considering limitations of information transmission from both cell-external and internal noise. We identify broad distributions of exponential gradients, which lead to log-normal stimuli and maximal drift velocity. Our results thus provide a first step towards deciphering the chemical nature of complex, experimentally inaccessible cellular microenvironments, such as the human intestine. 相似文献
998.
Iulia Lupan Genel Sur Diana Deleanu Victor Cristea Gabriel Samasca Peter Makovicky 《Annals of microbiology》2014,64(3):899-903
Intestinal microbiota plays an important role in maintaining the overall health of an individual. It can be affected by diet but also inflammation of the intestine due to various causes. In the last decade, particular attention has been paid to the study of the interaction between mucosal cells and intestinal microbiota, and to the host immune response to change in community structure. Here, we review the most significant studies on human microbiota in patients with celiac disease, and also the potential biotechnological use of microorganisms for the production of gluten-free products. 相似文献
999.
Jack?A?TuszynskiEmail author Philip?Winter Diana?White Chih-Yuan?Tseng Kamlesh?K?Sahu Francesco?Gentile Ivana?Spasevska Sara?Ibrahim?Omar Niloofar?Nayebi Cassandra?DM?Churchill Mariusz?Klobukowski Rabab?M?Abou?El-Magd 《Theoretical biology & medical modelling》2014,11(1):52
A variety of topics are reviewed in the area of mathematical and computational modeling in biology, covering the range of scales from populations of organisms to electrons in atoms. The use of maximum entropy as an inference tool in the fields of biology and drug discovery is discussed. Mathematical and computational methods and models in the areas of epidemiology, cell physiology and cancer are surveyed. The technique of molecular dynamics is covered, with special attention to force fields for protein simulations and methods for the calculation of solvation free energies. The utility of quantum mechanical methods in biophysical and biochemical modeling is explored. The field of computational enzymology is examined. 相似文献
1000.
Carolin R Loescher Tobias Gro?kopf Falguni D Desai Diana Gill Harald Schunck Peter L Croot Christian Schlosser Sven C Neulinger Nicole Pinnow Gaute Lavik Marcel M M Kuypers Julie LaRoche Ruth A Schmitz 《The ISME journal》2014,8(11):2180-2192
Nitrogen fixation, the biological reduction of dinitrogen gas (N2) to ammonium (NH4+), is quantitatively the most important external source of new nitrogen (N) to the open ocean. Classically, the ecological niche of oceanic N2 fixers (diazotrophs) is ascribed to tropical oligotrophic surface waters, often depleted in fixed N, with a diazotrophic community dominated by cyanobacteria. Although this applies for large areas of the ocean, biogeochemical models and phylogenetic studies suggest that the oceanic diazotrophic niche may be much broader than previously considered, resulting in major implications for the global N-budget. Here, we report on the composition, distribution and abundance of nifH, the functional gene marker for N2 fixation. Our results show the presence of eight clades of diazotrophs in the oxygen minimum zone (OMZ) off Peru. Although proteobacterial clades dominated overall, two clusters affiliated to spirochaeta and archaea were identified. N2 fixation was detected within OMZ waters and was stimulated by the addition of organic carbon sources supporting the view that non-phototrophic diazotrophs were actively fixing dinitrogen. The observed co-occurrence of key functional genes for N2 fixation, nitrification, anammox and denitrification suggests that a close spatial coupling of N-input and N-loss processes exists in the OMZ off Peru. The wide distribution of diazotrophs throughout the water column adds to the emerging view that the habitat of marine diazotrophs can be extended to low oxygen/high nitrate areas. Furthermore, our statistical analysis suggests that NO2− and PO43− are the major factors affecting diazotrophic distribution throughout the OMZ. In view of the predicted increase in ocean deoxygenation resulting from global warming, our findings indicate that the importance of OMZs as niches for N2 fixation may increase in the future. 相似文献