1,721,021 research outputs found
Applicazione di tecniche molecolari per l’identificazione di microalghe bentoniche tossiche (Ostreopsidaceae) in aree costiere dell’Adriatico settentrionale.
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DNA barcoding and phylogenetic relationships in marine toxic dinoflagellate genus Ostreopsis based on mithocondrial genes
Full text linkThe marine dinoflagellate genus Ostreopsis includes species producing potent toxic compounds, such as palytoxin and palytoxin analogs, which cause toxic blooms in Mediterranean and tropical or other temperate areas. Phylogenetic and phylogeographical analyses based on ribosomal data set revealed the existence of distinct species and, within them, clades related to geographical distribution. Due to a high morphological variability, species belonging to this genus are very difficult to identify and cryptic species could be present. Thus, developing a standardized DNA barcode approach for this marine dinoflagellate can allow confirming known species and uncover hidden variability with consequent description of new species. These information, besides leading to a better understanding of species diversity in natural environment, could assist in identification and detection of different species directly in field sample. This study represents the first attempt to assess the suitability of mitochondrial COI (cytochrome c oxidase 1) and cob (cytochrome b) as an identification tool for Ostreopsis species. For this purpose, we designed specific primers to amplify and sequence mitochondrial COI and cob genes from several Ostreopsis spp. isolates from worldwide areas. Phylogenetic analyses of single and concatenated mtDNA genes within genus Ostreopsis, as well as their intra and inter-specific divergences, were compared to those based on nuclear ribosomal genes LSU and 5.8S-ITS regions. Phylogenetic analyses of the genus Ostreopsis using mtDNA genes resulted uninformative, being not able to distinguish different species. Moreover, the so called 'barcode gap' that is interspecific variation exceeding intraspecific variation, was detected only in ribosomal genes. Thus, our original goal to apply the mtDNA barcode to recognize species within this toxic marine dinoflagellate was not accomplishe
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
Studio delle dinamiche di crescita di Ostreopsis cf. ovata con nuove metodologie molecolari di qrt-PCR
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Monitoring toxic Ostreopsis cf. ovata in recreational waters using a qPCR based assay.
No full textOstreopsis sp. is a toxic marine benthic dinoflagellate that causes high biomass blooms, posing a threat to human health, marine biota and aquaculture activities, and negatively impacting coastal seawater qual- ity. Species-specific identification and enumeration is fundamental because it can allow the implemen- tation of all the necessary preventive measures to properly manage Ostreopsis spp. bloom events in recreational waters and aquaculture farms. The aim of this study was to apply a rapid and sensitive qPCR method to quantify Ostreopsis cf. ovata abundance in environmental samples collected from Mediterra- nean coastal sites and to develop site-specific environmental standard curves. Similar PCR efficiencies of plasmid and environmental standard curves allowed us to estimate the LSU rDNA copy number per cell. Moreover, we assessed the effectiveness of mitochondrial COI and cob genes as alternative molecular markers to ribosomal genes in qPCR assays for Ostreopsis spp. quantification
Influenza di differenti forme chimiche di silice disciolta sulla crescita di diatomee marine.
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