Identification of a major secretory glycoprotein from rat epididymis: interaction with spermatozoa

A polypeptide with molecular mass of 17 kDa has been partially purified and identified as a major secretory glycoprotein in the rat epididymis. It is phosphorylated and contains high mannose-type oligosaccharides with 5 and 6 mannose units predominantly. These sugar residues are sufficiently exposed in the molecule to be released by endo-beta-N-acetylglucosaminidase H without prior denaturation or protease digestion. Specific binding of the glycoprotein to testicular spermatozoa was demonstrated with Ka 0.2 x 10(9) M-1 and 17,200 sites per cell, while no binding to epididymal spermatozoa was detectable. Direct labeling of surface proteins on cauda epididymis spermatozoa revealed the presence of a major band of 16.2 kDa, which may be equivalent to GP17. The interaction of the epididymal secretory protein with sperm suggests a possible role in the maturation process.     

Anonymous nuclear DNA markers in the American oyster and their implications for the heterozygote deficiency phenomenon in marine bivalves

A puzzling population-genetic phenomenon widely reported in allozyme surveys of marine bivalves is the occurrence of heterozygote deficits relative to Hardy-Weinberg expectations. Possible explanations for this pattern are categorized with respect to whether the effects should be confined to protein-level assays or are genomically pervasive and expected to be registered in both protein- and DNA-level assays. Anonymous nuclear DNA markers from the American oyster were employed to reexamine the phenomenon. In assays based on the polymerase chain reaction (PCR), two DNA-level processes were encountered that can lead to artifactual genotypic scorings: (a) differential amplification of alleles at a target locus and (b) amplification from multiple paralogous loci. We describe symptoms of these complications and prescribe methods that should generally help to ameliorate them. When artifactual scorings at two anonymous DNA loci in the American oyster were corrected, Hardy-Weinberg deviations registered in preliminary population assays decreased to nonsignificant values. Implications of these findings for the heterozygote-deficit phenomenon in marine bivalves, and for the general development and use of PCR-based assays, are discussed.      

Basolateral plasma membrane localization of ouabain-sensitive sodium transport sites in the secretory epithelium of the avian salt gland

The distribution of Na+ pump sites (Na+-K+-ATPase) in the secretory epithelium of the avian salt gland was demonstrated by freeze-dry autoradiographic analysis of [(3)H] ouabain binding sites. Kinetic studies indicated that near saturation of tissue binding sites occurred when slices of salt glands from salt-stressed ducks were exposed to 2.2 μM ouabain (containing 5 μCi/ml [(3)H]ouabain) for 90 min. Washing with label-free Ringer's solution for 90 min extracted only 10% of the inhibitor, an amount which corresponded to ouabain present in the tissue spaces labeled by [(14)C]insulin. Increasing the KCl concentration of the incubation medium reduced the rate of ouabain binding but not the maximal amount bound. In contrast to the low level of ouabain binding to salt glands of ducks maintained on a freshwater regimen, exposure to a salt water diet led to a more than threefold increase in binding within 9-11 days. This increase paralleled the similar increment in Na+-K+-ATPase activity described previously. [(3)H]ouabain binding sites were localized autoradiographically to the folded basolateral plasma membrane of the principal secretory cells. The luminal surfaces of these cells were unlabeled. Mitotically active peripheral cells were also unlabeled. The cell-specific pattern of [(3)H]ouabain binding to principal secretory cells and the membrane-specific localization of binding sites to the nonluminal surfaces of these cells were identical to the distribution of Na+-K+-ATPase as reflected by the cytochemical localization of ouabain-sensitive and K+-dependent nitrophenyl phosphatase activity. The relationship between the nonluminal localization of Na+-K+-ATPase and the possible role of the enzyme n NaCl secretion is considered in the light of physiological data on electrolyte transport in salt glands and other secretory epithelia.     

The early life history of two sympatric New Zealand octopuses: eggs and paralarvae of Octopus huttoni and Pinnoctopus cordiformis

This study combined morphological and morphometric information on egg clutches, egg capsules and paralarvae of two sympatric coastal octopuses from New Zealand waters, Octopus huttoni and Pinnoctopus cordiformis, to provide species-specific traits to identify their early life stages obtained from field surveys. Eggs of O. huttoni (2.5 mm length; 1 mm width) were entwined with one another forming strings that ranged from 11 to 25.8 mm in length. Eggs of P. cordiformis (6.4 mm length; 1.5 mm width) were significantly bigger than those of O. huttoni and were grouped in small clusters of about seven eggs. Paralarvae O. huttoni and P. cordiformis differed in hatching size (1.4 mm versus 3.1 mm mantle length), number of suckers per arm (four versus eight), number of lamellae per outer demibranch (five versus ten) and arrangements of chromatophores in the body surface (29 to 59 versus 91 to 179), respectively. The morphological traits described in hatchlings from the laboratory allowed comparisons with field-collected paralarvae, suggesting that such characters were reliable species-specific patterns to enable a consistent differentiation between the early life stages of these two sympatric species, even in the absence of the brooding female.     

Niche Partition of Bacteriovorax Operational Taxonomic Units Along Salinity and Temporal Gradients in the Chesapeake Bay Reveals Distinct Estuarine Strains

The predatory Bacteriovorax are Gram-negative bacteria ubiquitous in saltwater systems that prey upon other Gram-negative bacteria in a similar manner to the related genus Bdellovibrio. Among the phylogenetically defined clusters of Bacteriovorax, cluster V has only been isolated from estuaries suggesting that it may be a distinct estuarine phylotype. To assess this hypothesis, the spatial and temporal distribution of cluster V and other Bacteriovorax phylogenetic assemblages along the salinity gradient of Chesapeake Bay were determined. Cluster V was expected to be found in significantly greater numbers in low to moderate salinity waters compared to high salinity areas. The analyses of water and sediment samples from sites in the bay revealed cluster V to be present at the lower salinity and not high salinity sites, consistent with it being an estuarine phylotype. Cluster IV had a similar distribution pattern and may also be specifically adapted to estuaries. While the distribution of clusters V and IV were similar for salinity, they were distinct on temperature gradients, being found in cooler and in warmer temperatures, respectively. The differentiation of phylotype populations along the salinity and temporal gradients in Chesapeake Bay revealed distinct niches inhabited by different phylotypes of Bacteriovorax and unique estuarine phylotypes.     

Production of endothelial progenitor cells obtained from human Wharton's jelly using different culture conditions

Endothelial progenitor cells (EPC) participate in revascularization and angiogenesis. EPC can be cultured in vitro from mononuclear cells of peripheral blood, umbilical cord blood or bone marrow; they also can be transdifferentiated from mesenchymal stem cells (MSC). We isolated EPCs from Wharton's jelly (WJ) using two methods. The first method was by obtaining MSC from WJ and characterizing them by flow cytometry and their adipogenic and osteogenic differentiation, then applying endothelial growth differentiating media. The second method was by direct culture of cells derived from WJ into endothelial differentiating media. EPCs were characterized by morphology, Dil-LDL uptake/UEA-1 immunostaining and testing the expression of endothelial markers by flow cytometry and RT-PCR. We found that MSC derived from WJ differentiated into endothelial-like cells using simple culture conditions with endothelium induction agents in the medium.     

羌活与宽叶羌活的群体遗传结构和种间分化研究

为了合理利用羌活和宽叶羌活的药用植物资源,同时保护其物种多样性,该研究利用SSR分子标记技术对羌活与宽叶羌活邻域及异域分布的23个自然种群,共计227个个体进行多样性和种间分化研究.结果显示:(1)两个物种具有中等水平的遗传多样性;羌活的平均等位基因数(Na)、有效等位基因数(Ne)和期望杂合度(He)分别为2.603...     

Predation Pattern and Phylogenetic Analysis of <Emphasis Type="Italic">Bdellovibrionaceae</Emphasis> from the Great Salt Lake,Utah

The Bdellovibrionaceae are predatory, intraperiplasmic bacteria that prey upon a variety of Gram-negative bacteria. The prey susceptibility pattern is frequently used to characterize new isolates. The objective in this study was to isolate and characterize predators from the Great Salt Lake (GSL) by prey susceptibility testing. To recover the predators, water samples were inoculated into an enrichment medium with Vibrio parahaemolyticus as prey. After several days of incubation, the predators were isolated, pure DNA was extracted, and partial 16S rDNA gene was sequenced. Water samples were also plated for isolation of heterotrophic bacteria. The susceptibility of bacterial isolates from the lake and other sources to each predator isolate was determined. The results revealed that there are predators in the GSL, and they preferentially prey on bacteria from the lake. This is the first report of the isolation of Bdellovibrionaceae from GSL and the predators showing preferences for bacteria from the same habitat.