Gonadotropin-induced luminal formation in the seminiferous tubules and efferent ductules in young frogs: light and electron microscopic study

To clarify the mechanism of fluid secretion in the testes at the time of gonadotropin-induced spermiation, young Rana nigromaculata were used. As a morphological index of fluid secretion, luminal formation of the seminiferous tubules, and efferent ductules were observed. The following changes were seen by the administration of hCG or frog pituitary: first, the luminal formation of the seminiferous tubules was seen; next, tubular expansion became evident, and finally, luminal formation and expansion were observed in the efferent ductules. These changes were preceded by the separation of cell contact among Sertoli cells and of cell contact between Sertoli cells and the cells of efferent ductules only in the center and the swelling of Sertoli cells and cells of efferent ductules. With regard to the flow of fluid at the time of spermiation, the present results indicate the possibility that there is a difference in the ability for fluid secretion between Sertoli cells and the ductule cells.     

Syntheses of polypeptides corresponding to ribonuclease T1 and its analog, (59-tyrosine)-ribonuclease T1

Two polypeptides with the sequence of ribonuclease T₁ and its analog, [59-tyrosine]-ribonuclease T₁ were prepared by the solid-phase method. After purification by gel filtration and ion exchange chromatography, the synthetic peptides afforded similar patterns on paper and disc electrophoreses to those of natural enzyme. Further purification of the peptide corresponding to ribonuclease T₁ raised the specific activity to 59% for RNA and 44% for guanosine 2′,3′-cyclic phosphate. In case of [59-tyrosine]-ribonuclease T₁, the activity was raised to 61% and 57%, respectively.     

Improved β-glucan yield using an Aureobasidium pullulans M-2 mutant strain in a 200-L pilot scale fermentor targeting industrial mass production

β-(1→3)-D-glucans with β-(1→6)-glycosidic linked branches are known to be immune activation agents and are incorporated in anti-cancer drugs and health-promoting supplements. β-Glucan concentration was 9.2 g/L in a 200-L pilot scale fermentor using mutant strain Aureobasidium pullulans M-2 from an imperfect fungal strain belonging to A. pullulans M-1. The culture broth of A. pullulans M-2 had a faint yellow color, whereas that of the wild-type had an intense dark green color caused by the accumulation of melanin-like pigments. β-Glucan produced by A. pullulans M-2 was identified as a polysaccharide of D-glucose monomers linked by β-(1→3, 1→6)-glycosidic bonds through GC/MS and NMR analysis. When a conventional medium was used in the culture of A. pullulans M-2 in a 3-L jar fermentor, β-glucan concentration was 1.4-fold that produced by the wild-type. However, when a medium optimized by statistical experimental design was used with dissolved oxygen at 10%, the β-glucan concentration was 9.9 g/L with a yield of 0.52 (g β-glucan/g consumed sucrose), 2.9-fold that of the wild-type. This level of productivity was reproduced when the fermentation was scaled up 200-L. The industrial production of high β-glucan without melanin-like pigments is highly expected, as a health-promoting supplement or functional food.     

Infection with HIV is associated with elevated IL-6 levels and production

Polyclonal B cell activation is commonly observed in AIDS and in infection with HIV. Because IL-6 (B cell stimulatory factor 2) plays an essential role in the differentiation of activated B cells to Ig-secreting cells, and because IL-6 production is induced by exposure of human PBMC to HIV, we measured the level of circulating plasma IL-6, spontaneously-produced IL-6, and IL-6 mRNA in HIV-infected donors and in healthy control donors. Elevated levels of plasma IL-6 and IL-6 mRNA were detected in HIV-infected donors. PBMC isolated from the peripheral circulation of HIV-infected donors, and cultured without added exogenous activators of IL-6 production, produced markedly elevated amounts of IL-6 when compared with cells isolated from healthy donors. Interestingly, levels of an acute-phase protein, which is known to be induced by IL-6, was also increased in HIV-infected donors. These results demonstrate that elevated levels of IL-6 are associated with HIV-infection, and suggest that IL-6 over-production may contribute to the polyclonal B cell activation seen in AIDS and HIV infection.