Dynamic Immune Response to Vibriosis in Pacific Oyster Crassostrea gigas Larvae during the Infection Process as Supported by Accurate Positioning of GFP-Tagged Vibrio Strains.

As the immune system is not fully developed during the larval stage, hatchery culture of bivalve larvae is characterized by frequent mass mortality caused by bacterial pathogens, especially Vibrio spp. However, the knowledge is limited to the pathogenesis of vibriosis in oyster larvae, while the immune response to pathogenic microorganisms in this early life stage is still far from being fully elucidated. In this study, we combined green fluorescent protein (GFP)-tagging, histological and transcriptomic analyses to clarify the pathogenesis of experimental vibriosis and the mechanisms used by the host Pacific oyster Crassostrea gigas larvae to resist infection. The Vibrio strains first colonized the digestive system and rapidly proliferated, while only the transcription level of IκB kinase (IKK) and nuclear factor κB (NF-κB) associated with signaling transduction were up-regulated in oyster at 18 h post challenge (hpc). The mRNA levels for integrin ß-1, peroxinectin, and heat shock protein 70 (HSP70), which are associated with phagocytosis, cell adhesion, and cytoprotection, were not upregulated until 30 hpc when the necrosis already happened in the larval digestive system. This suggested that the immunity in the early stages of C. gigas is not strong enough to prevent vibriosis and future research may focus on the strengthening of the gastrointestinal immune ability to defend vibriosis in bivalve larvae.

An overview on the nomenclatural and phylogenetic problems of native Asian brine shrimps of the genus Artemia Leach, 1819 (Crustacea, Anostraca).

The genus Artemia Leach, 1819 is a cosmopolitan halophilic crustacean, consisting of bisexual species and obligate parthenogenetic populations. Asia is rich in Artemia biodiversity. More than 530 Artemia sites have been recorded from this area and more than 20 species/subspecies/variety names have been used for them. There exist various problems in the nomenclature, identification, and phylogenetic status of Artemia native to Asia, which are discussed in this paper.

Morphometric and preliminary genetic characteristics of Branchinecta orientalis populations from Iran (Crustacea: Anostraca).

Branchinecta orientalis is a fairy shrimp endemic to the Palearctic region, from Mongolia to Spain. The patchy nature of its habitat is thought to result in a high degree of subdivision among populations, potentially promoting speciation. We combined morphometric characteristics with molecular phylogeny of cytochrome c oxidase I (COI) to test whether B. orientalis could be a species complex and whether there is any correlation between the genetic variation, morphometric characteristics and geographical variables. We studied six populations from Iran based on the comparison of morphometric and molecular datasets, we confirmed that the Aigher Goli (AIG) population is biometrically well separated from the Akh Gol, Hassar, Rashakan, Khaslou and Garagojanlou populations in northwestern Iran. The relatively high genetic divergence in the AIG from the other populations and its congruence with morphometric data were observed in B. orientalis populations. However, as these results were generated using a small sample size and on a limited sampling range, they should be considered as preliminary.