Inhibition of spore germination of Ulva pertusa by the marine bacterium Pseudoalteromonas haloplanktis CI4

The effect of the bacterial strain CI4 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial biofilm and cell-free supernatant strongly inhibited spore germination. In attempts to define the chemical nature of the antifouling substance in the supernatant of CI4, the culture supernatants were tested for activity after heat treatment, enzymatic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with specific activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive effect on spore germination. Pronase and carboxypeptidase y did not significantly affect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium CI4 was identified as Pseudoalteromonas. haloplanktis based on the phenotypic characters and 16S rRNA gene analysis

Inhibition of spore germination of Ulva pertusa by the marine bacterium Pseudoalteromonas haloplanktis CI4

The effect of the bacterial strain CI4 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial biofilm and cell-free supernatant strongly inhibited spore germination. In attempts to define the chemical nature of the antifouling substance in the supernatant of CI4, the culture supernatants were tested for activity after heat treatment, enzymatic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with specific activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive effect on spore germination. Pronase and carboxypeptidase y did not significantly affect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium CI4 was identified as Pseudoalteromonas. haloplanktis based on the phenotypic characters and 16S rRNA gene analysis

Characterization and phylogenetic analysis of the complete mitochondrial genome from Rock Scallop (Crassadoma gigantea) using next-generation sequencing

In this study, the complete 18,495 by mitochondrial genome was determined from Rock scallop (Crassadoma gigantea) using next-generation sequencing technology. The complete mitochondria! genome contained 12 protein-coding genes (PCGs), 2 ribosomal RNA genes, 23 transfer RNA genes, without ATP8 and D-loop, which was similar with most mitochondrial genomes of marine bivalve molluscs. Gene annotations, including gene order, genetic code, start and stop codons and codons bias, were identified. Phylogenetic tree was constructed using Neighbor-Joining (NJ) method based on the PCGs showed the present species clustered within the Pteriomorphia Glade. This work should be of importance not only for the better understanding of the relationships within Pectinidae, but also for the development of useful genetic markers in Rock scallop aquaculture and restoration efforts.</p

High genetic diversity in population of Lepturichthys fimbriata from the Yangtze River revealed by microsatellite DNA analysis

Lepturichthys fimbriata (Gunther) is one of the benthic and rock-attached fish species that is typically found in torrential flows of the upper reaches of the Yangtze River in China. Several dams in the Yangtze River (the Ertan Dam, the Three Gorges Dam, the Gezhouba Dam, the Xiluodu Dam and the Xiangjiaba Dam (the latter two dams are under construction)) may have significant effects on the habitat and spawning behaviors of L. fimbriata, and could ultimately threaten the survival of this fish. We studied the population genetic diversity of L. fimbriata samples collected at three sites within the Yangtze River and one of its tributaries, the Yalong River. Genetic diversity patterns were determined by analyzing genetic data from 14 polymorphic microsatellite loci isolated in Jinshaia sinensis (Sauvage et Dabry). A high genetic diversity among these L. fimbriata local populations was indicated by the number of microsatellite alleles (A) and the expected heterozygosity. No reductions of genetic diversity in any L. fimbriata population were observed. However, significant population differentiations were observed among three local populations by pairwise comparisons (P<0.001). We deduced that L. fimbriata local populations were not small ones. In addition, the habitat behaviors of rock-attachment and possible residence of L. fimbriata could account for the genetic differences found in local populations.Lepturichthys fimbriata (Gunther) is one of the benthic and rock-attached fish species that is typically found in torrential flows of the upper reaches of the Yangtze River in China. Several dams in the Yangtze River (the Ertan Dam, the Three Gorges Dam, the Gezhouba Dam, the Xiluodu Dam and the Xiangjiaba Dam (the latter two dams are under construction)) may have significant effects on the habitat and spawning behaviors of L. fimbriata, and could ultimately threaten the survival of this fish. We studied the population genetic diversity of L. fimbriata samples collected at three sites within the Yangtze River and one of its tributaries, the Yalong River. Genetic diversity patterns were determined by analyzing genetic data from 14 polymorphic microsatellite loci isolated in Jinshaia sinensis (Sauvage et Dabry). A high genetic diversity among these L. fimbriata local populations was indicated by the number of microsatellite alleles (A) and the expected heterozygosity. No reductions of genetic diversity in any L. fimbriata population were observed. However, significant population differentiations were observed among three local populations by pairwise comparisons (P<0.001). We deduced that L. fimbriata local populations were not small ones. In addition, the habitat behaviors of rock-attachment and possible residence of L. fimbriata could account for the genetic differences found in local populations