Camellidins,Antifungal Saponins Isolated from Camellia japonica

Two triterpenoid saponins were isolated from an aqueous or a methanolic extract of camellia (Camellia japonica) leaf. They had an antifungal activity characterized by abnormal germination of conidia. These saponins were composed of 3βhydroxy-18β-acetoxy-28-norolean-12-en-16-one or 3β, 8β-dihydroxy-28-norolean-12-en-16-one as aglycon, and d-glucuronic acid, dglucose and two moles of dgalactose as the sugar moiety. The authors have named these new saponins “Camellidin,” which might have value for studies in the fields of phytopathology and biochemistry.     

Isolation and Restriction Mapping of a Pseudomonas Plasmid

The effects of the injection of a large amount of N¹ -methylnicotinamide (MNA) (500 mg per kg body weight) on the ratio of N¹ -methyl-4-pyridone-3-carboxamide (4-py) to N¹ -methyl-2-pyridone-5- carboxamide (2-py) excretion, and the activities of 2-py and 4-py forming MNA oxidases were investigated in rats. The injected MN A was excreted very rapidly into the urine; 46 % of the dose was excreted from 0~3hr post-injection, 15% from 3~6hr, 6% from 6~9hr and 1.5% from 9~ 12hr. The ratio of 4-py to 2-py also decreased rapidly; the ratio being about 0.6, 0.4, 0.4 and 0.6 from 0~3hr, 3~6hr, 6~9hr and 9~ 12hr post-injection, respectively. This ratio then recovered rapidly; being about 2, 5.5, 8.5 and 9.7 from 12~24 hr, 24 ~48 hr, 48~72 hr and 72 ~96 hr post-injection, respectively. The normal range of 4-py to 2-py excretion ratio is 8~14. So, this ratio returned to a normal level by day 3 post-injection. The rats were killed 5 hr after the MNA injection. At this time (the lowest ratio was observed around this time), the activities of 2-py and 4-py forming MNA oxidases in the injected group were 59 % and 11 % of the normal levels, respectively. Therefore, it was found that the decreased ratio of 4-py to 2-py excretion with the MNA injection was mainly due to the higher inhibition of the 4-py forming MNA oxidase than of the 2-py forming MNA oxidase by the MNA injection.     

Production and Properties of Lipase from a Newly Isolated Chromobacterium

Out of some 750 strains of microorganisms, a potent bacterium for lipase production was isolated from soil and was identified as Chromobacterium viscosum.

The bacterium accumulates lipase in culture fluid when grown aerobically at 26°C for 3 days in a medium composed of soluble starch, soy bean meal, lard and inorganic salts.

Chromobacterium lipase had an optimum pH of 7.0 for activity at 37°C, and an optimal temperature of 65°C at pH 7.0. The enzyme retained 80% of the activity when heated for 10 min at 70°C. This lipase was capable of hydrolyzing a variety of natural fats and oils, and it was more active on lard and butter than on olive oil. The activity was stimulated by Ca²⁺, Mg²⁺, Mn²⁺ and inhibited by Cu²⁺, Hg²⁺ and Sn²⁺. It was not diminished but rather stimulated by a high concentration of bile-salts.     

Reductive Dechlorination of 1,2,4-Trichlorobenzene by Staphylococcus epidermidis Isolated from Intestinal Contents of Rats

Twelve bacterial strains which were concerned with dechlorination of 1,2,4-trichlorobenzene (TCB) were isolated from the intestinal contents of rats and it was found that they belonged to Staphylococcus epidermidis (strain A-F), Staphylococcus saprophyticus (strain G), Streptococcus sp. (strains H and I), Bacillus sp. (strain J), Gram negative rod (strain K) and Lactobacillus sp. (strain L).

In Staphylococcus epidermidis (Strain A), TCB was mainly converted to o-dichlorobenzene and the latter was preferentially converted to monochlorobenzene (MCB) among dichlorobenzenes (DCBs). These conversions proceeded only under a gas phase of hydrogen. Furthermore, dry and broken cells of intact bacteria also maintained the dechlorinating activities, which were stimulated by the addition of NADPH.

Therefore, it was supposed that the conversion of TCB to MCB via DCBs was reductively carried out by enzymes originating from the isolated bacteria.     

Isolation and Identification of Ubiquinone 10 from Cultured Cells of Tobacco

Callus tissues were induced from stem and root segments of Rauwolfia serpentina. Growth and alkaloid production of the callus tissues were examined under various culture conditions. The growth was strikingly promoted in the presence of 2,4-D (0.5~1 ppm), kinetin (0.2~0.5 ppm) and yeast extract (0.1~0.2%). At favourable conditions, the growth value in 4 weeks’ culture was ca. 40 (F.W.), and ca. 25 (D.W.) for stem callus tissues, and ca. 15 (F.W.), and ca. 8 (D.W.) for root callus tissues. Stem and root callus tissues produced ajmaline and some other unidentified Rauwolfia alkaloids. The ajmaline content in root callus tissues was 10~20mg % and in stem callus tissues was 1~10mg %. The ajmaline production was strikingly reduced when 2,4-D concentration increased, or kinetin was omitted in the culture medium. Phytosterols including stigmasterol, β-sitosterol or cholesterol were also produced.     

Volatile Gas Components Contribute to Cigarette Smoke-induced DNA Single Strand Breaks in Cultured Human Cells

Thermostable purine nucleoside phosphorylases, PUN PI and PUNPII, have been purified from Bacillus stearothermophilus JTS 859. The characterization of PUNPI was reported previously. [Hori et al.₉ Agric. Biol. Chem. 53, 2205 (1989)] PUNPII had a molecular weight of 113,000, consisting of 4 identical subunits (M_w 28,000). The isoelectric point was 5.3. The Michaelis constants for inosine, guanosine, and adenosine were 0.22, 0.34, and 0.075 mm, respectively. The optimal temperature of the reaction was 70°C. The enzyme was stable at 70°C. Although other reported purine nucleoside phosphorylases were SH-enzymes, PUNPII was not a SH-enzyme because the enzyme reaction was not inhibited by PCMB and iodoacetic acid, the optimal pH of the enzyme reaction was from 7.0 to 11.0, and the enzyme did not contain cysteine.

PUNPII and PUNPI were different in several points. Not PUNPI but PUNPII could catalyze the phosphorolysis of adenosine. Specific activity of PUNPI and II for inosine were 405 and 50.6 μmol/min/mg protein at 60°C, respectively. PUNPI was stable at 80°C. PUNPII was stable at 70°C, but was denatured at 80°C.     

Extra tyrosine in the carbohydrate-binding module of Irpex lacteus Xyn10B enhances its cellulose-binding ability

The xylanase (Xyn10B) that strongly adsorbs on microcrystalline cellulose was isolated from Driselase. The Xyn10B contains a Carbohydrate-binding module family 1 (CBM1) (IrpCBM_Xyn10B) at N-terminus. The canonical essential aromatic residues required for cellulose binding were conserved in IrpCBM_Xyn10B; however, its adsorption ability was markedly higher than that typically observed for the CBM1 of an endoglucanase from Trametes hirsuta (ThCBM_EG1). An analysis of the CBM-GFP fusion proteins revealed that the binding capacity to cellulose (7.8 μmol/g) and distribution coefficient (2.0 L/μmol) of IrpCBM_Xyn10B-GFP were twofold higher than those of ThCBM_EG1-GFP (3.4 μmol/g and 1.2 L/μmol, respectively), used as a reference structure. Besides the canonical aromatic residues (W24-Y50-Y51) of typical CBM1-containing proteins, IrpCBM_Xyn10B had an additional aromatic residue (Y52). The mutation of Y52 to Ser (IrpCBM_Y52S-GFP) reduced these adsorption parameters to 4.4 μmol/g and 1.5 L/μmol, which were similar to those of ThCBM_EG1-GFP. These results indicate that Y52 plays a crucial role in strong cellulose binding.     

Late-maturing cooking rice Sensyuraku has excellent properties,equivalent to sake rice,for high-quality sake brewing

Low protein content and sufficient grain rigidity are desired properties for the rice used in high-quality sake brewing such as Daiginjo-shu (polishing ratio of the rice, less than 50%). Two kinds of rice, sake rice (SR) and cooking rice (CR), have been used for sake brewing. Compared with those of SR, analyses of CR for high-quality sake brewing using highly polished rice have been limited. Here we described the original screening of late-maturing CR Sensyuraku (SEN) as rice with low protein content and characterization of its properties for high-quality sake brewing. The protein content of SEN was lower than those of SR Gohyakumangoku (GOM) and CR Yukinosei (YUK), and its grain rigidity was higher than that of GOM. The excellent properties of SEN with respect to both water-adsorption and enzyme digestibility were confirmed using a Rapid Visco Analyzer (RVA). Further, we confirmed a clear taste of sake produced from SEN by sensory evaluation. Thus, SEN has excellent properties, equivalent to those of SR, for high-quality sake brewing.     

Moderate food restriction suppresses the conversion of l-tryptophan to nicotinamide in weaning rats

Calorie restriction leads to a change in the metabolism of nutrients. Nicotinamide is biosynthesized from l-tryptophan. We attempted to determine the effects of food restriction on the biosynthesis of nicotinamide from l-tryptophan. Weaning male rats were fed a conventional chemically defined diet without preformed niacin for 63?d. However, the food intake was restricted to 80 and 65% of the intake of the ad libitum-fed control group of rats. The 24-h urine samples were periodically collected, and the urinary excretion of nicotinamide and its catabolites was measured. The conversion percentages were lower in both restricted groups than in the ad libitum-fed control group during the experimental period (control group, 1.37?±?0.24%; 80%-restricted group, 0.20?±?0.04%; 65%-restricted group, 0.15?±?0.02%; control vs. restricted groups, p?<?0.01). Food restriction, even at mild level, suppressed the conversion of l-tryptophan to nicotinamide when compared to the ad libitum-fed control group.     

Studies on Biologically Active Substances Formed by Bacilli

The products of several Bacillus strains were investigated on rabbit serum calcium decreasing, oxytocic and toad heart function promoting activities. These products were obtained from the clear supernatant fluid of the culture medium after the cells were removed by centrifugation.

For the production of rabbit serum calcium decreasing substance, Bacillus subtilis K and Bacillus natto No. 8 were found to be usefull, Bacillus megaterium KM, Bacillus cereus var. mycoides and Bacillus subtilis K produced oxytocic principle. Bacillus subtilis K, Bacillus brevis and Bacillus megaterium KM also produced toad heart function promoting factor.

A procedure was developed to obtain the electrophoretically homogenous rabbit serum calcium decreasing substance from culture filtrate of Bacillus subtilis K. The crude substance was obtained as isoelectric precipitate by adjusting the culture filtrate to pH 3.0. The crude substance was purified by gel filtration on a Sephadex G-75 column, isoelectric fractionation and chromatography on DEAE-cellulose column. The purified preparation was shown to be homogenous by Tiselius electrophoresis but was separated into two bands by polyacrylamide electrophoresis. The chemical analysis of this biologically active substance indicated this substance to be a lipoprotein. The substance decreased rabbit serum calcium level about 12% at 6~8hr after intravenous injection (dose; 0.5 mg/kg body weight).