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The taxonomic position of the bivalve pathogen PP-638 was studied together with five similar isolates. The strains were isolated from flat oyster (Ostrea edulis) and Manila clam (Venerupis philippinarum) cultures during outbreaks of disease in two shellfish hatcheries (Galicia, NW Spain). The pathogenicity, previously established for PP-638, was demonstrated with all isolates and for several bivalve species, including the original hosts. On the basis of phenotypic characterization and 16S rRNA gene sequences, a tight group was defined within the genus Vibrio. Multilocus sequence analysis (MLSA) based on concatenated sequences of the 16S rRNA gene and the five housekeeping genes recA, rpoA, pyrH, gyrB and ftsZ revealed that these strains form a cluster within the Orientalis clade, close to the species Vibrio tubiashii. The results of MLSA, the DDH rate and the phenotypic differences with the type strain of V. tubiashii supported the differentiation of the Galician isolates as a new subspecies within V. tubiashii, for which the name V. tubiashii subsp. europaeus [corrected] subsp. nov. is proposed (type strain PP-638(T)=CECT 8136(T)=DSM 7349(T)) The emended description of V. tubiashii is included. The pathogenicity assays widen the host range of V. tubiashii to add two unreported species, Venerupis decussata and Donax trunculus, and the described as relatively resistant species V. philippinarum., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Seabirds are often free from blood parasites, and a recent review suggested that phylogenetic, ecological and life-history parameters can determine the prevalence of blood parasites in seabirds. However, there is a lack of data available from many seabird groups, and a larger database is needed to understand prevalence patterns of blood parasites. We used a molecular screening approach to detect parasites of the genera Plasmodium, Haemoproteus, Leucocytozoon and Babesia in five species of two genera of seabirds that breed on Atlantic Ocean islands off Brazil. The observed patterns differed between the two bird genera. Like other Laridae, brown noddy, Anous stolidus adults were infected with Haemoproteus with low prevalence. Masked boobies, Sula dactylatra and brown boobies, Sula leucogaster were infected with Babesia. Of the latter, mainly juveniles were infected. In all species, intensity of infection (i.e. number of infected erythrocytes) was so low that parasites remained undetected in blood smears. This may explain the absence of major effects on the body condition of birds, although infected juvenile masked boobies were lighter than juveniles that were not infected with Babesia. Two tree-nesting species; black noddy, Anous minutus and red-footed booby, Sula sula did not have blood parasites, suggesting that tree-nesting may reduce the exposure to arthropod vectors compared with ground nesting in these species.

Acylhomoserine lactone (AHLs)-mediated quorum-sensing (QS) processes seem to be common in the marine environment and among marine pathogenic bacteria, but no data are available on the prevalence of bacteria capable of interfering with QS in the sea, a process that has been generally termed 'quorum quenching' (QQ). One hundred and sixty-six strains isolated from different marine dense microbial communities were screened for their ability to interfere with AHL activity. Twenty-four strains (14.4%) were able to eliminate or significantly reduce N-hexanoyl-l-homoserine lactone activity as detected by the biosensor strain Chromobacterium violaceum CV026, a much higher percentage than that reported for soil isolates, which reinforces the ecological role of QS and QQ in the marine environment. Among these, 15 strains were also able to inhibit N-decanoyl-l-homoserine lactone activity and all of them were confirmed to enzymatically inactivate the AHL signals by HPLC-MS. Active isolates belonged to nine different genera of prevalently or exclusively marine origin, including members of the Alpha- and Gammaproteobacteria (8), Actinobacteria (2), Firmicutes (4) and Bacteroidetes (1). Whether the high frequency and diversity of cultivable bacteria with QQ activity found in near-shore marine isolates reflects their prevalence among pelagic marine bacterial communities deserves further investigation in order to understand the ecological importance of AHL-mediated QS and QQ processes in the marine environment., (© 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

The allozyme variation between 2 sympatric populations of Lecithochirium furcolabiatum and L. rufoviride was examined with the aim to investigate if the 2, morphologically similar, helminths are reproductively distinct. Three enzyme loci, Gpd, Pgm-1, and Idh were found to be diagnostic for the 2 species. These results support the conclusion that the worms are different biological species. Only the Gpi and Gdh loci showed no differences. Marked genetic subdivision was detected at the Idh locus in the L. rufoviride population. Given that the genotypic distribution at Pgm-I showed no significant deviations from Hardy-Weinberg expectations, it does not appear that the absence of heterozygotes for Idh was caused by the reproductive structure of the population. Although there are several other possible reasons for the deficiency of heterozygotes in natural populations, the existence of a new noninterbreeding group within the population studied constitutes a plausible explanation.