Potassium fluxes in Neocosmospora vasinfecta.

The unidirectional K+ fluxes across the mycelial surface of Neocosmospora vasinfecta were determined using 42K. Influx was mediated by at least two kinetically distinct systems, one having an apparent Km of 6-5 mu-equiv. K+/l and the other of about 1-0 m-equiv. K+/l. The VMAX for both systems was in the range 18 to 22 mu-equiv. K+/100 mg mycelial dry matter/h (1-0 to 1-2 m-equiv. K+/l cell-water/min). Influx was strongly inhibited by 2,4-dinitrophenol, sodium azide, sodium arsenate and anaerobiosis. K+ efflux was dependent on the external K+ concentration and ranged from 3 to 10% of mycelial K+/h. The maximum efflux rate was always considerably less than the initial influx rate for the K+ concentrations examined. During incubation in dilute KCl solutions, K+ influx decreased to a value approaching the K+ efflux rate. It is considered that equilibrium with external K+ is attained primarily by the regulation of K+ influx, and that this may be the principal mechanism controlling cytoplasmic K+ levels. Adsorption of K+ was also observed throughout the K+ concentration range examined and can be attributed to two distinct K+-binding entities at the mycelial surface, half-saturating at approximately O-I mM-and 4-4 mM-KCl respectively.     

Evidence for insulin synthesis in normal mouse seminal vesicle based on in situ RNA-DNA hybridization

Cultured seminal vesicle epithelial cells exhibited cytoplasmic immunoreactivity following treatment with anti-insulin antisera. In addition, these cultured epithelial cells were found, by in situ hybridization with a radiolabeled insulin complementary deoxyribonucleic acid (cDNA) probe, to contain an insulin or insulin-like messenger ribonucleic acid (mRNA). Autoradiograms of the hybridized cells exhibited heavy labeling over the cytoplasm and minimal distribution of grains over the nuclei and background areas. These observations indicate that cultured mouse seminal vesicle epithelium contains an insulin or insulin-like peptide as well as the mRNA that is required for its synthesis.     

Towards a phylogenetic classification of reef corals: the Indo‐Pacific genera Merulina,Goniastrea and Scapophyllia (Scleractinia,Merulinidae)

Recent advances in scleractinian systematics and taxonomy have been achieved through the integration of molecular and morphological data, as well as rigorous analysis using phylogenetic methods. In this study, we continue in our pursuit of a phylogenetic classification by examining the evolutionary relationships between the closely related reef coral genera Merulina, Goniastrea, Paraclavarina and Scapophyllia (Merulinidae). In particular, we address the extreme polyphyly of Favites and Goniastrea that was discovered a decade ago. We sampled 145 specimens belonging to 16 species from a wide geographic range in the Indo‐Pacific, focusing especially on type localities, including the Red Sea, western Indian Ocean and central Pacific. Tree reconstructions based on both nuclear and mitochondrial markers reveal a novel lineage composed of three species previously placed in Favites and Goniastrea. Morphological analyses indicate that this clade, Paragoniastrea Huang, Benzoni & Budd, gen. n., has a unique combination of corallite and subcorallite features observable with scanning electron microscopy and thin sections. Molecular and morphological evidence furthermore indicates that the monotypic genus Paraclavarina is nested within Merulina, and the former is therefore synonymised.     

Immunocytochemical localization of insulin-like immunoreactivity in mouse seminal vesicle

Insulin-like immunoreactivity was localized in tissue sections and cell cultures of mouse seminal vesicle using the indirect technique of immunocytochemistry. Seminal vesicles were cut into fragments, fixed in 2.5% glutaraldehyde, embedded in epoxy resin, sectioned at 1 micron, and transferred to glass slides. Epithelial cell cultures of seminal vesicle were grown on coverslips in Dulbecco's Minimal Essential Medium for 4-6 days and fixed in 2.5% glutaraldehyde. Sections (etched with sodium ethanolate) or coverslips were incubated in guinea pig antiporcine insulin antiserum, in antiserum immunoabsorbed with porcine insulin, or in normal guinea pig serum. For indirect immunocytochemistry, incubation with primary antiserum was followed by treatment with rabbit anti-guinea pig immunoglobulin (Ig) G conjugated to peroxidase, or with protein A and then rabbit peroxidase anti-peroxidase (PAP). Finally, treated samples were incubated in phenylenediamine-pyrocatechol-H2O2 substrate mixture for 6-8 min at room temperature. Specific immunoreactivity to insulin antisera was confined to the epithelium of the seminal vesicle in tissue sections. No staining occurred in subepithelial connective tissue. Specific immunoreactivity was also observed in the cytoplasm of cultured seminal vesicle epithelial cells.