Influence of extract of Rosa rugosa roots on lipid levels in serum and liver of rats

The effects of the methanol extract of Rosa rugosa roots on serum and liver lipids were studied in rats. The rats were fed the purified diets with or without the methanol extract at the 1% level for 4 weeks. The concentrations of serum and liver total cholesterol were not significantly affected by the feeding of extract. Feeding of the extract, on the other hand, reduced the liver triacylglycerol content without influencing the serum triacylglycerol level. The effects of the extract on lipids profiles were diminished markedly by dietary cholesterol. The results suggest an existence of component in the extract which may ameliorate the accumulation of triacylglycerol in rat liver.     

Characteristics of a novel high viscosity polysaccharide,methylan, produced byMethylobacterium organophilum

Summary A new anionic high molecular weight polysaccharide, Methylan, was produced byMethylobacterium organophilum from methanol as a sole source of carbon and energy under the specific culture conditions. By GPC and light scattering, the molecular weight was determined to be 2–4×10⁶ dalton and the distribution of molecular weight was very homogeneous. Methylan was composed of carbohydrate (80%), uronic acid (12%), protein (6%) and pyruvic acid (5%). The sugar composition of Methylan was identified as glucose, galactose and mannose with the approximate molar ratio of 232. Methylan solution showed a pseudoplastic non-Newtonian fluid property at the concentration above 0.05%. At the concentration of 1% Methylan solution, the consistency index was 18,000 centipoise which was almost 10 times higher than that of Xanthan and the flow behavior index was 0.15.     

Purification and properties of intracellular fructosyl transferase fromAureobasidium pullulans

Intracellular frustosyl transferase was purified fromAureobasidium pullulans C-23 by ethanol fractionation, CM-Sephadex chromatography and preparative disc gel electrophoresis. It was shown to be homogeneous on disc polyacrylamide gel electrophoresis, with a molecular size of 190kDa. The pI value of the enzyme was about 3.7. The enzyme has aK _m value of 0.43 mM for sucrose and was optimally active at pH 5.0 and 60°C. The enzyme was stable from pH 2.5 to 12. It was almost completely inhibited by 5mM Hg²⁺ but was not significantly affected by other cations. The transferase was inactivated by treatment with the tryptophan-specific reagentN-bromosuccinimide and the tyrosine-specific reagent, I₂, suggesting that tryptophan and tyrosine residues are probably located at or near the active site of the enzyme.     

湖北宜昌震旦系-寒武系界线地层Micrhystridium regulare化石的发现及其地层意义

该文记述了国际前寒武系-寒武系界线层型候选剖面所在地,湖北宜昌震旦系-寒武系界线地层中发现的小刺球藻类化石Micrhystridium regulare,regulare,讨论了它们的产出层位及其归属,并对小刺球藻类化石在时间上、空间上的分布作了简要的归纳,最后提出了小刺球藻类化石在震旦系-寒武系界线地层的划分和大区域地层对比中重要的潜在作用。     

Mechanisms of heat protection by cycloheximide or puromycin: Involvement of polyamines?

1. 1.|When Chinese hamster ovary cells are treated with cycloheximide (10 μg/ml) or puromycin (100 μg/ml) for 2 h before and during heating at 43°C for 3 h, there is protection from hyperthermic killing; i.e. the plating efficiency increases 2000-fold from 3.7 × 10⁻⁵ to (6–9) × 10⁻².

2. 2.|The total intracellular levels of spermidine and spermine are not altered by the hyperthermic or drug treatments.

3. 3.|The small 30% decrease in intracellular putrescine observed after heating is not altered by drug treatment.

4. 4.|Heat protection by treatment with cycloheximide or puromycin cannot be attributed to changes in levels of total intracellular polyamines.

Resolution of the stereoisomers of leucovorin and 5-methyltetrahydrofolate by chiral high-performance liquid chromatography

Leucovorin (5-formyltetrahydrofolate, LV) is a reduced folate that has been in clinical use for many years as a rescue agent following methotrexate (MTX) therapy. Commercially available LV is a 1:1 mixture of [6R]-and [6S]-isomers. Due to the lack of a specific method for directly separating and quantitating the stereoisomers of LV, it has been difficult to precisely define the pharmacokinetic and biological characteristics of each stereoisomer. We have now developed a novel HPLC method to completely separate [6S]-LV and [6S]-5-methyltetrahydrofolate (MeTHF) from their respective [6R]-isomers using bovine serum albumin (BSA)-bonded silica as the chiral stationary phase. Baseline separation was achieved using 5 and 25 mM sodium phosphate buffers (pH 7.4) as the mobile phase with resolution factors of 1.65 for LV and 2.31 for MeTHF, respectively. The purity of each isomer prepared by this HPLC method is greater than 99%. The stereoisomers were identified by examining their ability to protect CEM cells from MTX (0.04 microM)-induced inhibition of growth. In the LV chromatogram, the first eluted peak provided complete protection from MTX growth inhibition when LV concentrations of 0.1 microM and above were used, whereas the last eluted peak failed to reverse MTX toxicity at concentrations up to 1.0 microM. Chemically pure synthetic [6R]-and [6S]-LV standards confirmed that the first eluted, biologically active peak is the [6S]-isomer. For MeTHF, only the last eluted peak effectively protects cells from MTX growth inhibition and is therefore believed to be the [6S]-isomer. This new HPLC method will serve as a useful tool to elucidate the clinical and cellular pharmacology of the stereoisomers of LV and MeTHF.     

Structure of the horseradish peroxidase isozyme C genes

We have isolated, cloned and characterized three cDNAs and two genomic DNAs corresponding to the mRNAs and genes for the horseradish (Armoracia rusticana) peroxidase isoenzyme C (HPR C). The amino acid sequence of HRP C1, deduced from the nucleotide sequence of one of the cDNA clone, pSK1, contained the same primary sequence as that of the purified enzyme established by Welinder [FEBS Lett. 72, 19-23 (1976)] with additional sequences at the N and C terminal. All three inserts in the cDNA clones, pSK1, pSK2 and pSK3, coded the same size of peptide (308 amino acid residues) if these are processed in the same way, and the amino acid sequence were homologous to each other by 91-94%. Functional amino acids, including His40, His170, Tyr185 and Arg183 and S-S-bond-forming Cys, were conserved in the three isozymes, but a few N-glycosylation sites were not the same. Two HRP C isoenzyme genomic genes, prxC1 and prxC2, were tandem on the chromosomal DNA and each gene consisted of four exons and three introns. The positions in the exons interrupted by introns were the same in two genes. We observed a putative promoter sequence 5' upstream and a poly(A) signal 3' downstream in both genes. The gene product of prxC1 might be processed with a signal sequence of 30 amino acid residues at the N terminus and a peptide consisting of 15 amino acid residues at the C terminus.     

Reaction products of a new anti-cancer agent, Pt(IV)(cyclohexyldiamine)Cl4, with guanosine and 9-methylguanine: first crystal structures of Pt(cyclohexyldiamine) complexes with a nucleobase and a nucleoside

Pt(IV)(dach)Cl4 (dach = cyclohexyldiamine) was reacted with guanosine and 9-methylguanine and their reaction products were analyzed by single-crystal x-ray diffraction. In both cases the resulting complexes, [Pt(dach)(guanosine)2]2+ and [Pt(dach)(9-methylguanine)2]2+ respectively, corresponded to an unanticipated reduction of the octahedral Pt(IV) starting material to a square planar Pt(II) species. The nature of the reducing agent is presently unknown.     

Chromatofocusing of mammalian estrone sulfate sulfohydrolase activity

Estrone sulfate sulfohydrolase (estrogen sulfatase) activity was solubilized by treatment with Triton X-100 from 105,000 g pellets of guinea pig uterus, testis and brain, as well as from rat liver and human placenta. The solubilized forms were subjected to chromatofocusing in the fast protein liquid chromatography (FPLC) system and on conventional columns packed in our laboratory. The guinea pig tissue pattern was complex. Uterus showed peaks of activity with apparent pI's of 9.11 and 7.6; testis contained 3 peaks with pI's of 9.18, 8.7 and 7.5; brain possessed peaks with pI's of 9.28 and 8.6. In each case the major activity peak was that with pI greater than 9. Rat liver activity chromatofocused as a single peak of apparent pI = 6.87 and the human placental enzyme also showed a single, though broad, peak, of pI = 6.57. This suggests not only that the guinea pig enzyme(s) differs markedly from those of rat liver and human placenta, but that there may be qualitative differences between the forms in the three guinea pig tissues. Chromatofocusing behaviour was not independent of the specific exchange resins and ampholytes utilized. The recovered enzyme activity was fairly stable and it seems that chromatofocusing could be a useful step in purification of the guinea pig enzyme(s), particularly the main form possessing a pI greater than 9.