We propose a role for Galphai/o protein activation and subsequent interaction of Gbetagamma with PLCbeta in mediating the proapoptotic effects of ethanol upon the developing neural crest.
Yersinia pestis is the causative agent of the bubonic, septicemic, and pneumonic plagues (also known as black death) and has been responsible for recurrent devastating pandemics throughout history. To further understand this virulent bacterium and to accelerate an ongoing sequencing project, two whole-genome restriction maps (XhoI and PvuII) of Y. pestis strain KIM were constructed using shotgun optical mapping. This approach constructs ordered restriction maps from randomly sheared individual DNA molecules directly extracted from cells. The two maps served different purposes; the XhoI map facilitated sequence assembly by providing a scaffold for high-resolution alignment, while the PvuII map verified genome sequence assembly. Our results show that such maps facilitated the closure of sequence gaps and, most importantly, provided a purely independent means for sequence validation. Given the recent advancements to the optical mapping system, increased resolution and throughput are enabling such maps to guide sequence assembly at a very early stage of a microbial sequencing project.There are 11 species in the genus Yersinia, 3 of which are pathogenic for humans (Yersinia pestis, Y. enteroclitica, and Y. pseudotuberculosis). Of the three pathogenic species, Y. pestis, which lives in rodents, transmits this pathogen to humans via fleas, causing bubonic, septicemic, and pneumonic plagues (also known as black death). Y. pestis has been responsible for many recurrent devastating pandemics throughout history, resulting in widespread loss of human life (1,7,22). To understand the molecular mechanisms that define the pathogenicity of this bacterial species, sequencing of two strains (KIM and CO-92 biovar Orientalis) of Y. pestis was funded by the National Institute of Allergy and Infectious Diseases and Beowulf Genomics. The two separate sequencing projects were conducted by F. Blattner's laboratory (University of WisconsinMadison) and Sanger Center (Hinxton, United Kingdom), using the strategy of whole-genome shotgun sequencing (11). Although this sequencing strategy has racked up an impressive number of completed microbial genomes, it can be further optimized in terms of the cost and effort required during the finishing stages. In this regard, physical maps serve to guide sequence assembly, characterize gaps, and validate the finished sequence. Furthermore, ordered restriction maps are particularly useful when attempting to assemble genomic regions containing repeats, since cleavage patterns can accurately discern such sequence elements.The costly appellation of "finished," assumed when dealing with high-quality sequence data, minimally mandates that no genomic region be excluded from the final results (23) and thus requires extensive finishing efforts. The chances that entire regions of a genome might be excluded from "completed" sequence increases in the face of limited budgets and the absence of physical mapping data. Because of these issues, optical maps were used (15) at an early stage of sequence assembly to iden...
The selective, saturable effect of n-alcohols upon Ca2+ mobilization in neural crest is consistent with a hypothesis that ethanol stimulates these signals through specific interaction with one or more alcohol-binding sites on a target protein. Octanol may overcome structural constraints imposed upon C6 and C7 in interacting with this protein target; alternatively, it may interact through a unique binding site.
In mouse, the establishment of left-right (LR) asymmetry requires intracellular calcium (Cai2+) enrichment on the left of the node. The use of Cai2+ asymmetry by other vertebrates, and its origins and relationship to other laterality effectors are largely unknown. Additionally, the architecture of Hensen's node raises doubts as to whether Cai2+ asymmetry is a broadly conserved mechanism to achieve laterality. We report here that the avian embryo uses a left-side enriched Cai2+ asymmetry across Hensen's node to govern its lateral identity. Elevated Cai2+ was first detected along the anterior node at early HH4, and its emergence and left-side enrichment by HH5 required both ryanodine receptor (RyR) activity and extracellular calcium, implicating calcium-induced calcium release (CICR) as the novel source of the Cai2+. Targeted manipulation of node Cai2+ randomized heart laterality and affected nodal expression. Bifurcation of the Cai2+field by the emerging prechordal plate may permit the independent regulation of LR Cai2+ levels. To the left of the node, RyR/CICR and H+V-ATPase activity sustained elevated Cai2+. On the right, Cai2+ levels were actively repressed through the activities of H+K+ATPase and serotonin-dependent signaling, thus identifying a novel mechanism for the known effects of serotonin on laterality. Vitamin A-deficient quail have a high incidence of situs inversus hearts and had a reversed calcium asymmetry. Thus, Cai2+ asymmetry across the node represents a more broadly conserved mechanism for laterality among amniotes than had been previously believed.
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