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51.
Mesoscale circulation generated by the Loop Current in the Northern Gulf of Mexico (NGOM) delivers growth-limiting nutrients to the microbial plankton of the euphotic zone. Consequences of physicochemically driven community shifts on higher order consumers and subsequent impacts on the biological carbon pump remain poorly understood. This study evaluates microbial plankton <10 μm abundance and community structure across both cyclonic and anti-cyclonic circulation features in the NGOM using flow cytometry (SYBR Green I and autofluorescence parameters). Non-parametric multivariate hierarchical cluster analyses indicated that significant spatial variability in community structure exists such that stations that clustered together were defined as having a specific ‘microbial signature’ (i.e. statistically homogeneous community structure profiles based on relative abundance of microbial groups). Salinity and a combination of sea surface height anomaly and sea surface temperature were determined by distance based linear modeling to be abiotic predictor variables significantly correlated to changes in microbial signatures. Correlations between increased microbial abundance and availability of nitrogen suggest nitrogen-limitation of microbial plankton in this open ocean area. Regions of combined coastal water entrainment and mesoscale convergence corresponded to increased heterotrophic prokaryote abundance relative to autotrophic plankton. The results provide an initial assessment of how mesoscale circulation potentially influences microbial plankton abundance and community structure in the NGOM. 相似文献
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Claudio Stalder Agostina Vertino Antonietta Rosso Andres Rüggeberg Claudius Pirkenseer Jorge E. Spangenberg Silvia Spezzaferri Osvaldo Camozzi Sacha Rappo Irka Hajdas 《PloS one》2015,10(10)
Cold-water coral (CWC) ecosystems occur worldwide and play a major role in the ocean''s carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago). However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata) that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents 相似文献
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Mosca A Russo F Miragliotta L Iodice MA Miragliotta G 《Journal of microbiological methods》2007,68(2):392-395
Over the last years, the clinical importance of mycobacteria has been raised. In this regard, it is important their identification in order to establish either the clinical significance or the appropriate therapy of the disease. Biochemical tests are usually time consuming until the report of results, that is why more rapid techniques are needed. As an alternative identification method, we have used a commercially available system for microbial identification based on whole cellular fatty acids analysis using gas-chromatography (GC). Sixty-eight strains of Mycobacterium tuberculosis, Mycobacterium gordonae, Mycobacterium xenopi, Mycobacterium kansasii, Mycobacterium fortuitum, and Mycobacterium avium-intracellulare were clearly identified by their unique fatty acid profile using the Sherlock Microbial Identification System (MIS). The results were in agreement with those obtained with traditional methods. This method is highly automated, rapid, easy to perform with a sample preparation for lipid analysis which is neither time consuming nor requiring a particular expertise. On this basis the MIS-GC method for the identification of some clinically important mycobacteria appears to be suitable for routine clinical use. 相似文献
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Pedrini B Placzek WJ Koculi E Alimenti C LaTerza A Luporini P Wüthrich K 《Journal of molecular biology》2007,372(2):277-286
Ciliates of Euplotes species constitutively secrete pleiotropic protein pheromones, which are capable to function as prototypic autocrine growth factors as well as paracrine inducers of mating processes. This paper reports the amino acid sequence and the NMR structure of the pheromone En-6 isolated from the antarctic species Euplotes nobilii. The 63-residue En-6 polypeptide chain forms three alpha-helices in positions 18-25, 36-40 and 46-56, which are arranged in an up-down-up three-helix bundle forming the edges of a distorted trigonal pyramid. The base of the pyramid is covered by the N-terminal heptadecapeptide segment, which includes a 3(10)-turn of residues 3-6. This topology is covalently anchored by four long-range disulfide bonds. Comparison with the smaller pheromones of E. raikovi, a closely related species living in temperate waters, shows that the two-pheromone families have the same three-helix bundle architecture. It then appears that cold-adaptation of the En proteins is primarily related to increased lengths of the chain-terminal peptide segments and the surface-exposed loops connecting the regular secondary structures, and to the presence of solvent-exposed clusters of negatively charged side-chains. 相似文献
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PTX3 interacts with inter-alpha-trypsin inhibitor: implications for hyaluronan organization and cumulus oophorus expansion 总被引:1,自引:0,他引:1
Scarchilli L Camaioni A Bottazzi B Negri V Doni A Deban L Bastone A Salvatori G Mantovani A Siracusa G Salustri A 《The Journal of biological chemistry》2007,282(41):30161-30170
Pentraxin 3 (PTX3) and heavy chains (HCs) of inter-alpha-trypsin inhibitor (IalphaI) are essential for hyaluronan (HA) organization within the extracellular matrix of the cumulus oophorus, which is critical for in vivo oocyte fertilization and female fertility. In this study, we examined the possibility that these molecules interact and cooperate in this function. We show that HCs and PTX3 colocalize in the cumulus matrix and coimmunoprecipitate from cumulus matrix extracts. Coimmunoprecipitation experiments and solid-phase binding assays performed with purified human IalphaI and recombinant PTX3 demonstrate that their interaction is direct and not mediated by other matrix components. PTX3 does not bind to IalphaI subcomponent bikunin and, accordingly, bikunin does not compete for the binding of PTX3 to IalphaI, indicating that PTX3 interacts with IalphaI subcomponent HC only. Recombinant PTX3-specific N-terminal region, but not the PTX3-pentraxin C-terminal domain, showed the same ability as full-length protein to bind to HCs and to enable HA organization and matrix formation by Ptx3(-/-) cumulus cell oocyte complexes cultured in vitro. Furthermore, a monoclonal antibody raised against PTX3 N terminus, which inhibits PTX3/IalphaI interaction, also prevents recombinant full-length PTX3 from restoring a normal phenotype to in vitro-cultured Ptx3(-/-) cumuli. These results indicate that PTX3 directly interacts with HCs of IalphaI and that such interaction is essential for organizing HA in the viscoelastic matrix of cumulus oophorus, highlighting a direct functional link between the two molecules. 相似文献
60.
Lepori MB Lovicu M Dessi V Zappu A Incollu S Zancan L Giacchino R Iorio R Vajro P Maggiore G Marcellini M Barbera C Pellecchia MT Simonetti R Kostic V Farci AM Solinas A De Virgiliis S Cao A Loudianos G 《Genetic testing》2007,11(3):328-332
Herein we report the results of mutation analysis of the ATP7B gene in a group of 134 Wilson disease (WD) families (268 chromosomes) prevalently of Italian origin. Using the SSCP and sequencing methods we identified 71 disease-causing mutations. Twenty-four were novel, while 19 more mutations already described, were identified in new populations in this study. A known mutation G591D showed a regional distribution, since it was only detected in 38.5% of the analyzed chromosomes in WD patients originating from Apulia, a region of South Italy. Detection of new mutations in the ATP7B gene increases our capability of molecular analysis that is essential for early diagnosis and treatment of WD. 相似文献