Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man

In order to clarify whether a dietary fiber has any effect upon the intestinal absorption of sulfonylurea, changes in plasma concentration of glibenclamide were determined during a six-hour period in nine healthy volunteers who took 2.5 mg of glibenclamide together with a breakfast and 3.9 g of glucomannan in a form of konjac powder and were compared with those of the control experiment in which the same amount of the hypoglycemic agent was given without the dietary fiber. In the control, mean plasma glibenclamide level increased rapidly, reaching a peak at 60 min and decreased gradually thereafter, whereas an increase in plasma glibenclamide level was blunted in the test experiment, thus plasma concentration of glibenclamide being lower at 30, 60, 90 and 150 min compared with the corresponding value of the control (31.7 +/- 24.5 ng/ml vs 76.4 +/- 25.0 ng/ml at 30 min; 51.3 +/- 35.5 ng/ml vs 120.9 +/- 56.0 ng/ml at 60 min; 60.0 +/- 38.8 ng/ml vs 117.4 +/- 53.1 ng/ml at 90 min; 54.0 +/- 31.5 ng/ml vs 100.7 +/- 46.5 ng/ml at 150 min). Mean plasma glucose concentration was significantly lower at 30 min in the test experiment than in the control despite the lower level of plasma glibenclamide in the former. The results suggest that glucomannan may influence the intestinal absorption of glibenclamide. A dietary fiber must be prescribed in due consideration of these facts.     

Construction and Characterization of Isogenic Series of Saccharomyces cerevisiae Polyploid Strains

Tetraploid cells of Saccharomyces cerevisiae are generated spontaneously in a homothallic MATa/MATα diploid population at low frequency (approximately 10⁻⁶ per cell) through the homozygosity of mating-type alleles by mitotic recombination followed by homothallic switching of the mating-type alleles. To isolate tetraploid clones more effectively, a selection method was developed that used a dye plate containing 40 mg each of eosin Y and amaranth in synthetic nutrient agar per liter. It was possible to isolate tetraploid clones on the dye plate at a frequency of 1 to 3% among the colonies colored dark red in contrast to the light red of the original diploid colonies. Isogenic series of haploid to tetraploid clones with homozygous or heterozygous genomic configurations were easily constructed with the tetraploid strains. No significant differences in specific growth rate or fermentative rate were observed corresponding to differences in ploidy, although the haploid clones showed a higher frequency of spontaneous respiratory-deficient cells than did the others. However, a significant increment in the fermentative rate in glucose nutrient medium was observed in the hybrid strains constructed with two independent homozygous cell lines. These observations strongly suggest that the polyploid strains favored by the brewing and baking industries perform well not because of the physical increment of the cellular volume by polyploidy but because of the genetic complexity or heterosis by heterozygosity of the genome in the hybrid polyploid cells.     

Effects of W-7 on catecholamine release and 45Ca2+ uptake in cultured adrenal chromaffin cells.

Effects of N-(6-aminohexyl)-5-chloro-1-naph-thalenesulfonamide (W-7), a calmodulin antagonist, on catecholamine (CA) release and ⁴⁵Ca²⁺ uptake were studied using cultured bovine adrenal chromaffin cells. W-7 inhibited the carbamylcholine (CCh)-evoked CA release and ⁴⁵Ca²⁺ uptake in a concentration-dependent manner. The inhibitory effect of W-7 on CCh-evoked CA release was not overcome either by an increase in extracellular calcium or CCh concentration. Although W-7 inhibited the high K⁺-evoked CA release and ⁴⁵Ca²⁺ uptake, potency of the drug was approximately 50–100 fold less than when inhibiting the CCh-evoked CA release and ⁴⁵Ca²⁺ uptake. The inhibitory effects of W-7 were observed both in norepinephrine release and epinephrine release. Moreover, W-7 inhibited the CCh-evoked ⁴⁵Ca²⁺ efflux. These results suggest that the inhibition of CA release by W-7 in adrenal chromaffin cells is mainly due to its inhibition of calcium uptake. W-7 may influence the linkage between acetylcholine-receptor and calcium uptake with higher potency than depolarization-dependent calcium entry.     

Temperature-Induced Change of Chlorophyll a Forms in Phosphatidylcholine Liposomes

Absorption spectra of chlorophyll a in phosphatidylcholine liposomesat different temperatures were analyzed by a curve fitting method.The absorption spectrum was found to be composed of one majorband with a peak at 670–671 nm and minor bands with peaksat 650–652, 662–663 and 684–686 nm. Upon coolingbelow the phase transition temperature of the lipid, the componentabsorbing at 670–671 nm increased significantly at theexpense of the component absorbing at 662–663 nm. No changein the extents of other bands was observed. ¹ CIW-DPB Publication No. 795. ²On leave from the Department of Biology, Faculty of Science,Kanazawa University, Marunouchi, Kanazawa 920, Japan. (Received December 20, 1982; Accepted April 27, 1983)     

Genetic studies of the ribosomal proteins in Escherichia. coli. II. Altered 30s ribosomal protein component specific to spectinomycin resistant mutants

Summary Spectinomycin resistant (spc ^r) mutants were obtained by treating the cells of E. coli K12, W3637 with nitrosoguanidine. The compositions of ribosomal proteins were analyzed for six out of eleven such spc ^r-mutants with chromatography on a carboxymethyl cellulose (CMC) column. The 30s ribosomal subunit from all of the spc ^r-mutants was found to contain the altered 30-4 protein component, while no difference was detected in 50s ribosomal proteins between spc ^r and spc ^s bacteria.Abbreviations used CMC carboxymethyl cellulose - str streptomycin - spc spectinomycin     

Energy-requiring uptake of protoberberine alkaloids by cultured cells ofThalictrum flavum

Cultured cells ofThalictrum flavum take up berberine exogenously added to medium against the concentration gradient. This uptake was temperature-dependent and sensitive to plasma membrane-bound ATPase inhibitors such as sodium orthovanadate and diethylstilbestrol, indicating that the process is mediated by an energy-requiring system. The time-course of pH-shift during berberine uptake suggests the participation of a berberine-proton antiport system in the berberine uptake by the cultured cells. In addition, the existence of a specific transport system was suggested by the competitive inhibition of berberine uptake by berberine analogues, coptisine and jatrorrhizine.     

Identification of viruses infected in Rehmannia glutinosa Libosch. var purpurea Makino and effect of virus infection on root yield and iridoid glycoside contents

Virus free plants of Rehmannia glutinosa Libosch. var. purpurea Makino were obtained through meristem tip tissue cultures from plants infected with a mixture of tabocco mosaic virus(TMV), a member of the carlavirus group, and an unknown spherical virus. The re-infection rate of the virus free plants by TMV in the field was determined by enzyme linked immunosorbent assay(ELISA). Twenty seven percent of the plants were re-infected during the first year, 31 % by the end of second year, and 63 % by the end of the third year. The yield of root and iridoid glycoside contents gradually decreased each year. These results led to the conclusion that virus infection causes marked decrease of the yield of roots and productivity of secondary metabolites.     

Effect of oxygen supply on berberine production in cell suspension cultures and immobilized cells ofThalictrum minus

The ample supply of O₂ proved to be of great importance for berberine production in cell suspension culture ofThalictrum minus, as the specific O₂ consumption rate of berberine-producing cells was twice as high as that of non-producing cells. Furthermore, berberine yield increased with increases in the volumetric O₂ transfer coefficient (K_La). Estimation of the optimum conditions of oxygen supply in suspension cultures and immobilized cells according to a known theoretical model assuming O₂ uptake by cells to be a zero-order reaction was in good agreement with the experimental data. The O₂ supply to immobilized cells could be improved by reducing the cell density and radius of the bead.     

Interconversion of polyamines in wild-type strains and mutants of yeasts and the effects of polyamines on their growth

Yeasts of wild-type strains, such as Saccharomyces cerevisiae, Schizosaccharomyces pombe and Candida albicans were shown to have the ability to form aminopropylcadaverine and aminopropylhomospermidine from cadaverine and homospermidine, respectively. A polyamine autotroph S. cerevisiae 179-5, which lacks ornithine decarboxylase, produced both aminopropylcadaverine and aminopropylhomospermidine, while another mutant S. cerevisiae Y 260 A, which lacks spermine synthase, formed only aminopropylcadaverine. Naturally-occurring triamines and tetraamines except norspermidine and norspermine stimulated the growth of S. cerevisiae 179-5. All the six aliphatic diamines with carbon chain length ranging from one to six were effective in activating the growth of S. cerevisiae 179-5, though all of them were not converted to either triamines or tetraamines.