1,25-Dihydroxyvitamin D stimulates sodium-dependent phosphate transport by renal outer cortical brush-border membrane vesicles by directly affecting membrane fluidity

We examined the effects of several forms of vitamin D added to renal brush-border membrane suspensions on phosphate and glucose transport and on membrane fluidity. The 1,25-D stimulated and the other vitamin D decreased phosphate uptake. In contrast, glucose uptake was not affected by the treatment of vitamin D. The 1,25-D resulted in a significant shift of the lower transition temperature in Arrhenius plots for phosphate, but not for glucose uptakes, from 15 degrees C to 11.5 degrees C. These data indicate that the 1,25-D may alter membrane fluidity, limited to the phosphate transporter, thus affecting the phosphate uptake.     

Potential bile acid metabolites. 14. Hyocholic and muricholic acid stereoisomers

The complete set of the eight theoretically possible stereoisomeric 3,6,7-trihydroxy-5 beta-cholanic acids, four of which are new, related to hyocholic and muricholic acids were prepared from chenodeoxycholic acid. The principal reactions used were 1) cis-dihydroxylation of delta 6-compounds with osmium tetroxide/N-methylmorpholine N-oxide; 2) trans-dihydroxylation of 6 alpha, 7 alpha-epoxy compounds with boron trifluoride etherate in N,N-dimethyl-formamide; 3) inversion of equatorial 3 alpha-hydroxylated compounds to the corresponding 3 beta-epimers with diethyl azodicarboxylate/triphenylphosphine/formic acid; and 4) stereoselective reduction of 7-keto derivatives with zinc borohydride (or sodium borohydride) and by metallic potassium/tert-amyl alcohol.     

Electron microscopic radioautographic study of the localization of an anti-allergic agent, Tranilast, in rat mast cells.

We have previously reported that Tranilast, an anti-allergic agent, was rapidly taken into the cytoplasm of rat mast cells in vitro by means of light microscopic radioautography. The present study was performed at the electron microscopic level to elucidate the fine localization of this agent in the mast cells. The results revealed that the number of radioautographic silver grains in the cells increased by the incubation with 3H-labelled Tranilast for 0 to 60 min. and that many silver grains were localized on the specific granules, especially on the perigranular membranes. These results suggest that the mode of inhibitory action of mast cell degranulation by Tranilast is related to the specific localization of this agent on the perigranular membranes.     

Functional mapping of amino acid residues responsible for the antibacterial action of apidaecin.

Functional mapping was carried out to address the amino acid residues responsible for the activity of the antibacterial peptide apidaecin from the honeybee by an in vivo assay system developed previously. The C-terminal region and many of the proline and arginine residues which are present at high frequency in apidaecin were found to play an important role in its antibacterial activity.     

On-line measurement of cell mass and specific growth rate by a laser turbidity meter coupled with data smoothing using a one-pass method

Summary A data smoothing algorithm by a one-pass method, employing spline function was applied to a laser turbidity meter for on-line measurement of cell mass and specific growth rate in the culture using recombinant E.coli The outputs from the laser turbidity meter containing noise and errors were successfully filtered by the method, leading to more reliable estimation of cell mass and specific growth rate in real time.     

Biological effects and binding properties of transforming growth factor-beta on human oral squamous cell carcinoma cells

The effects of transforming growth factor-beta (TGF-beta) on three human oral squamous cell carcinoma cell lines, HSC-2, HSC-3, and HSC-4, were investigated. Although these cell lines were equally sensitive to epidermal growth factor, responses to TGF-beta were variable. Dose-dependent inhibition of cell growth and [3H]thymidine incorporation of HSC-4 were observed by the addition of TGF-beta, whereas growth inhibitory effects on HSC-2 and HSC-3 were marginal. Moreover, treatment of HSC-4 with TGF-beta led to a more than 300-fold increase in fibronectin secretion into the medium. In contrast, TGF-beta did not increase the secretion of fibronectin on HSC-2 and HSC-3. Scatchard analysis of the binding of TGF-beta suggested that all squamous cell carcinoma cell lines have similar binding properties, with two classes of binding sites for TGF-beta. Affinity labeling of 125I-TGF-beta to cell surface receptors revealed the two major affinity crosslinked bands with Mr values of 65 kDa (type I) and 280 kDa (type III). A concomitant loss of 85 kDa band (type II) was observed in all squamous carcinoma cell lines examined. Although the proportions of type I and type III receptors were variable, the type I receptor, which is reported to be the main functional receptor in mediating the TGF-beta action, was commonly observed in these squamous cell carcinoma cell lines. These results indicate that the heterogeneity in response to TGF-beta between cell lines may be due to the difference in the signal transduction pathway of TGF-beta.     

Cryptic Plasmids in Glutamic Acid-producing Bacteria

Seven filamentous (fil) mutants were isolated from B. subtilis, and the mutations were mapped by means of lysed-protoplast transformation. Five of the mutations were linked to aroD and the others to pyrD. rgn mutations, which lead to a decrease in autolysin(s) and the formation of filaments, were also linked to aroD, and the mapping order was rgn-dnaE-aroD. On comparison with other reported filamentous mutations (lyt-1, lyt-2 and lyt-152), fil-1, fil-3 to -6, rgn and the above lyt mutations were determined to be in the same locus. All of the seven fil strains lacked flagella and showed decreased aμtolysin activity. Among them, only mutants having arod- linked mutations showed low competency. Protease assay results indicated that rgn mutants produce a several times higher amount of the enzyme than the parent strain, and the initiation time for the production in rgn mutants was two hours earlier than in the parent strain.