A new lysozyme from the eastern oyster, Crassostrea virginica, and a possible evolutionary pathway for i-type lysozymes in bivalves from host defense to digestion.

Background: Lysozymes are enzymes that lyse bacterial cell walls, an activity widely used for host defense but also modified in some instances for digestion. The biochemical and evolutionary changes between these different functional forms has been well-studied in the c-type lysozymes of vertebrates, but less so in the i-type lysozymes prevalent in most invertebrate animals. Some bivalve molluscs possess both defensive and digestive lysozymes.

Characterization of the major plasma protein of the eastern oyster, Crassostrea virginica, and a proposed role in host defense.

The major plasma protein of the eastern oyster, Crassostrea virginica, was purified, characterized and named dominin. SDS-PAGE analyses revealed that dominin consistently made up more than 40% of eastern oyster plasma and extrapallial fluid proteins. Three different forms of dominin were observed under non-reducing conditions.

Serine protease inhibitor cvSI-1 potential role in the eastern oyster host defense against the protozoan parasite Perkinsus marinus.

The serine protease inhibitor cvSI-1, purified from plasma of eastern oysters, inhibited the proliferation of the protozoan parasite Perkinsus marinus in vitro. In situ hybridization located cvSI-1 gene expression in basophil cells of the digestive tubules and cvSI-1 expression measured by real-time quantitative reverse transcriptase polymerase chain reaction was several hundred folds greater in digestive glands than in other organs examined or circulating hemocytes. cvSI-1 gene expression was also significantly greater in winter than in summer.

Evidence indicating the existence of a novel family of serine protease inhibitors that may be involved in marine invertebrate immunity.

A new serine protease inhibitor, designated cvSI-2, was purified and characterized from the plasma of the eastern oyster, Crassostrea virginica. CvSI-2 inhibited the serine protease subtilisin A in a slow-tight binding manner, with an overall dissociation constant Ki* of 0.18 nM.

cDNA cloning and tissue expression of plasma lysozyme in the eastern oyster, Crassostrea virginica.

The cDNA sequence of a 17,861 Da lysozyme first purified from plasma of eastern oysters (Crassostrea virginica) was identified and its complete amino acid sequence deduced. The amino acid sequence of the plasma lysozyme, designated cv-lysozyme 1, contained both a unique and a conserved region when compared to the amino acid sequences of other bivalve lysozymes. In situ hybridisation located cv-lysozyme 1 gene expression in mantle and gill cells in standard histological sections.

Calving sex ratio as related to the predicted Y-chromosome-bearing spermatozoa ratio in bull ejaculates.

The first objective was to correlate calving sex-ratio data from semen lots with the semen sex ratio obtained by two duplex polymerase chain reaction (PCR)/gel electrophoresis techniques. The two techniques involved different starting DNA amounts, PCR conditions, agarose gel concentrations, sample placement on the gels, lane size, number of lanes per gel, and duration of electrophoresis. The second objective was to sequence the duplex PCR products to verify their match to genes and chromosomes for which they were designed.

Chromosomal localization of a proinsulin transgene in Japanese quail by laser pressure catapulting.

Transgenic avian bioreactors produce therapeutic recombinant proteins in egg white. To date, however, methods for transgenic modification of the avian genome or determining transgenic status of individual birds are scarce. The dual, but interrelated, goals of this research were to: (1) develop a method of detecting stable DNA insertion into Japanese quail; and (2) provide a method for gene location on avian chromosomes.

A novel slow-tight binding serine protease inhibitor from eastern oyster (Crassostrea virginica) plasma inhibits perkinsin, the major extracellular protease of the oyster protozoan parasite Perkinsus marinus.

A serine protease inhibitor was purified from plasma of the eastern oyster, Crassostrea virginica. The inhibitor is a 7609.6 Da protein consisting of 71 amino acids with 12 cysteine residues that are postulated to form 6 intra-chain disulfide bridges.

Plasmid-mediated high-level gentamicin resistance among enteric bacteria isolated from pet turtles in Louisiana.

The sale of small turtles is banned by the Food and Drug Administration from the U.S. market due to concerns about their excretion of Salmonella spp.

Effects of cecropin B transgene expression on Mannheimia haemolytica serotype 1 colonization of the nasal mucosa of calves.

Objective: To express a cecropin B transgene on bovine nasal mucosa and determine the effect on Mannheimia haemolytica serotype 1 (S1) colonization.

Animals: 27 crossbred beef calves.

Procedure: The antibacterial efficacy of cecropin B against M.

SRY-related genes in the genome of the rice field eel (Monopterus albus).

The mammalian sex determining gene, SRY, is the founding member of the new growing family of Sox (SRY-like HMG-box gene) genes. Sox genes encode transcription factors with diverse roles in development, and a few of them are involved in sex determination and differentiation. We report here the existence of Sox genes in the rice field eel, Monopterus albus, and DNA sequence information of the HMG box region of five Sox genes.