1,721,006 research outputs found
Rapid identification of Pseudomonas spp. From aquatic samples using Terminal Restriction Fragment Lenght Polymorphism analysis
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Bacteria associated with the rapid tissue necrosis of stony corals
No full textWe investigated bacterial assemblages associated with corals displaying symptoms of the “White Syndrome” (WS), a general term used for indicating the appearance of bands, spots or patches of tissue loss, which is devastating wide areas of tropical ecosystems worldwide. We collected WS-diseased (n = 15) and healthy (n = 15) corals from the natural reef (Indonesia, Indian Ocean) and from large public aquaria. By using culture-dependent and culture-independent techniques, we found that a large fraction (73%) of the investigated WS events was associated with the presence of a high bacterial abundance and, specifically, of Vibrio spp.. Vibrio harveyi, a pathogen of many marine organisms and recently involved in coral Yellow Band disease, was the most represented species, being recovered from five out of 15 diseased corals. In experimental infection assays s, two V. harveyi strains, isolated from diseased corals, were inoculated on a total of 62 healthy colonies of Pocillopora damicornis. WS signs appeared in 57, confirming their ability of V. harvey strains to induce the disease . We conclude that Vibrio harveyi is one of the coral pathogens involved in the appearance of WS. However, not all of the WSs investigated were associated to Vibrio harveyi detection, nor to other Vibrio species (such as V. coralliilyticus). supporting the hypothesis that WS is not caused exclusively by Vibrio spp., but rather can have a multifactorial etiology, or can represent a group of diseases caused by a variety of agents . Further investigations to identify specific virulence traits will contribute to the understanding of the role of V. harveyi in WS pathogenesis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Archaeal Diversity in Deep-Sea Sediments Estimated by Means of Different Terminal-Restriction Fragment Length Polymorphisms (T-RFLP) Protocols
No full textMolecular approaches for the assessment of fecal bacterial contamination in marine harbor sediments.
No full textSustainable impact of mussel farming in the Adriatic Sea (Mediterranean Sea): evidence from biochemical, microbial and meiofaunal indicators
No full textArchaeal diversity in deep-sea sediments estimated by means of different Terminal-Restriction Fragment Length Polymorphisms (T-RFLP) protocols
No full textDespite the increasing recognition of the quantitative importance of Archaea in all marine systems, the protocols for a rapid estimate of Archaeal diversity patterns in deep-sea sediments have been only poorly tested yet. Sediment samples from 11 deep-sea sites (from 79°N to 36°N, at depths comprised from 469 to 5,571 m) were used to compare the performance of two different primer sets (ARCH21f/ARCH958r and ARCH109f/ARCH 915r) and three restriction enzymes (AluI, Rsa I, and HaeIII) for the fingerprinting analysis of Archaeal diversity using terminal-restriction fragment length polymorphisms (T-RFLP). In silico and experimental analyses indicated that different combinations of primer sets and restriction enzymes provided different values of benthic Archaeal ribotype richness and different Archaeal assemblage compositions. The use of the ARCH109f/ARCH 915r primer set in combination with AluI provided the best results (a number of ribotypes up to four folds higher than other combinations), suggesting that this primer set should be used in future studies dealing with the analysis of the patterns of Archaeal diversity in deep-sea sediments. Multivariate multiple regression analysis revealed that, whatever the T-RFLP protocol utilized, latitude and temperature explained most of the variance in benthic Archaeal ribotype richness, while water depth had a negligible role
Measuring species richness based on microbial community fingerprints: the emperor has no clothes - Authors reply
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