Med,a cell-surface localized protein regulating a competence transcription factor gene,comK, in Bacillus subtilis

Med was found as a positive regulator for comK, a master regulator for late competence genes. It was found by Western analysis that the ComK level was decreased in a med mutant. Experiments using an alkaline phosphatase fusion with Med and Western analysis of Med were done because a putative lipo-modification signal is found at the N-terminus of Med. The results obtained are consistent with the localization of Med at the cell surface. An implication of the cell-surface localization of Med is discussed in terms of comK regulation.     

Casein digestion by Debaryomyces hansenii isolated from cheese

To understand the possible proteolytic contribution of yeast during cheese ripening, Debaryomyces hansenii 212 was isolated from commercial blue-veined cheese and incubated in a medium containing casein. Growth and casein degradation were recognized at the cheese-ripening temperature. Proteolytic activity was found in the intracellular fraction, and the enzyme, which was attached to the cell wall, primarily acted on beta-casein. The cytosol contained more than 90% of the total proteolytic activity which was responsible for the degradation of both alpha(s)- and beta-casein. These results suggest that the contribution of yeast to cheese ripening would depend on the susceptibility to cell lysis in addition to its proteolytic activity.     

Effects of quantity and quality of dietary protein on the brain polysome profile in aged rats

The purpose of this study was to determine whether the quantity and quality of dietary protein affected the polysome profile of the brain in aged rats. Two experiments were done on three groups of aged rats (30 wk) given the diets containing 20% casein, 5% casein, or 0% casein (experiment 1), and 20% casein, 20% gluten, or 20% gelatin (experiment 2) for 10 d. The aggregation in brain ribosomes declined with a decrease of quantity and quality of dietary protein except in the hippocampus. The RNA concentration (mg RNA/g protein) did not differ among the three groups varying the dietary protein in any brain regions. The results suggest that the higher quantity and quality of dietary protein improves the polysome profile in the brain of aged rats, and that the polysome profile is at least partly related to the mechanism by which the dietary protein affects brain protein synthesis in aged rats.     

Effects of oolong tea on metabolism of plasma fat in mice under restraint stress

We investigated the effects of oolong tea on the basic metabolism of plasma lipids in mice under restraint stress. When a lipid emulsion (Intralipid 20%; a lipid emulsion containing 20% soybean oil) was injected intravenously into mice, the restraint stress prolonged the half-life (T 1/2) of elimination for plasma triglyceride (TG) from 28.7 to 55.5 min. The elimination rate per minute was 48.2% in stressed mice with the rate in starved control mice as 100%. Therefore, TG metabolism was disrupted by the stress, and the use of TG as an energy source decreased. We found that the metabolism of lipids significantly response to the restrained stress in the present study. Plasma TG was 515.9 +/- 29.9mg/dl 35min after Intralipid administration in control stressed mice, 478.7 +/- 26.7 mg/dl in the stressed group given caffeine 100 mg/kg of body weight, and 418.3 +/- 18.4 mg/dl in the stressed group given 1,000 mg/kg oolong tea, an improvement by 7.2% and 18.9%, respectively, with the value for the untreated control group. The intake of oolong tea alleviated the stress-induced decrease in the rate of blood lipid metabolism; this effect may have arisen from some non-specific stress-relieving property of the tea or from acceleration of lipid metabolism by properties of polyphenols, etc. in tea. Oolong tea had anti-stress effects on plasma TG metabolism, and the effects did not depend on caffeine.     

Changes in flower coloration and sepal anthocyanins of Cyanic delphinium cultivars during flowering

The changes in flower color related to sepal pigmentation of cyanic Delphinium cultivars were investigated during anthesis. The sepal hues of the purple and blue flowered varieties observed on the initial day of unfurling had changed with a decrease in hue angle three days after anthesis. In both the purple and blue cultivars, violdelphin (3) was the major component on day one of anthesis, and the chromaticity improved with increasing sepal concentrations of violdelphin (3) and cyanodelphin (4) after three days of unfurling. The flower hue was dominated by the constitution of acylated anthocyanins, and the chromaticity was ordered by the sepal concentration. The biosynthesis of cyanodelphin (4) from violdelphin (3) was postulated since an increase in the sepal concentration of cyanodelphin (4) was accompanied by a decrease in violdelphin (3). Acylation of the anthocyanins was initiated by an increase in the respective possible precursors, tulipanin (2) and violdelphin (3), to subsequently synthesize violdelphin (3) and cyanodelphin (4) during flowering.     

Preventive effect of a chicken extract on the development of hypertension in stroke-prone spontaneously hypertensive rats

The antihypertensive effect of Brand's Essence of Chicken (BEC), a popular chicken extract used as a traditional health food, was examined with stroke-prone spontaneously hypertensive rats (SHRSPs). The animals were maintained from 6 to 25 weeks of age on drinking water with or without BEC. The BEC-fed group showed a significant reduction in the development of hypertension when compared with the control animals. The levels of blood urea nitrogen and plasma creatinine in the BEC-fed group were significantly lower than those in the control group, suggesting that the renal glomerular function had been improved by the daily administration of BEC. It thus seems likely that BEC would be useful as a prophylactic treatment against the development of hypertension and renal injury.     

Membrane-rigidifying effects of anti-cancer dietary factors

Since several anti-cancer drugs interact with cell membrane lipids, the effects of anti-cancer dietary factors on liposomal membranes with different lipid composition were comparatively studied by measuring fluorescence polarization. Fluidity was imparted on both hydrophobic and hydrophilic regions of lipid bilayers by decreasing cholesterol and increasing unsaturated phosphatidylcholine in membranes. At 0.625-10 microM, (-)-epigallocatechin gallate, genistein, apigenin, resveratrol and a reference anti-cancer drug, doxorubicin, rigidified the tumor cell model membranes consisting of 20 mol% cholesterol and 80 mol% phosphatidylcholine with the acyl chain 18:1/16:0 ratio of 1.0, but not daidzein. They were more effective on the membrane core than the membrane surface. Quercetin showed a biphasic effect on the hydrophobic regions of membrane lipid bilayers to rigidify above 5 microM and fluidize below 2.5 microM. In contrast, anti-cancer dietary factors and doxorubicin were not or much less effective in rigidifying the normal cell model membranes consisting of 40 mol% cholesterol and 60 mol% phosphatidylcholine with the acyl chain 18:1/16:0 ratio of 0.5. The membrane-rigidifying effects were greater depending on a decrease of the cholesterol/phosphatidylcholine ratio and an increase of the phosphatidylcholine unsaturation degree. Membrane-active dietary factors and doxorubicin inhibited the growth of mouse myeloma cells at 10-100 microM, while the growth inhibition by membrane-inactive daidzein was relatively weak. Anti-cancer dietary factors appear to act on more fluid membranes like tumor cells as well as doxorubicin to induce rigidification, especially in the hydrocarbon core of membrane lipids, which is determined by the composition of cholesterol and unsaturated phospholipids.     

Half-life of cholesterol 7alpha-hydroxylase activity and enzyme mass differ in animals and humans when determined by a monoclonal antibody against human cholesterol 7alpha-hydroxylase

A monoclonal antibody against human cholesterol 7alpha-hydroxylase was produced, and the half-life of the enzyme was studied. Both the activity and protein mass of the enzyme were measured at timed intervals during microsomal incubation. The enzyme activity dropped rapidly; the half-life was 1, 1.7 and 3h in humans, rats and rabbits, respectively. In contrast, the protein mass, measured by immunoblotting, declined slowly; its half-life was 5h in the human and 9h in the rat and rabbit enzymes. This suggests that there may be vulnerable sites responsible for the enzyme activity. Addition of dithiothreitol (DTT) restored the decreased activity considerably, indicating that at least one sulfhydryl group is involved in the vulnerability. These results show considerable decrement in cholesterol 7alpha-hydroxylase activity due to sulfhydryl groups.     

<Emphasis Type="Italic">Heteroepichloë</Emphasis>, gen. nov. (Clavicipitaceae; Ascomycotina) on bamboo plants in East Asia

The causal agents of witches' broom of bamboo plants in East Asia, Epichloë bambusae and E. sasae, were morphologically and phylogenetically examined. The phylogenetic studies were conducted using ITS 1, 2, and 5.8 S rDNA regions. Both Epichloë species produce Ephelis-type conidia in artificial medium and are phylogenetically situated in different clades from Epichloë and Parepichloë. Here, we propose a new genus Heteroepichloë for these two bambsicolous Epichloë species.