Primers for the amplification of sequence‐characterized loci in Cryphonectria cubensis populations

We describe the development of DNA markers for the fungal pathogen of Eucalyptus, Cryphonectria cubensis. These markers originated from cloned intershort sequence repeat polymerase chain reactions, which enrich for medium to highly repetitive DNA sequences. In total, 10 markers were isolated, eight of which were polymorphic, and these can subsequently be applied to study populations of C. cubensis.     

Structural analysis of the carbohydrate moieties of α-l-fucosidase from human liver

Acid -l-fucosidase (EC 3.2.1.51) was obtained from human liver and purified to homogeneity. The enzyme consists of four subunits; each of these has a molecular mass of 50 kD_a and bears oneN-linked carbohydrate chain. The structures of these chains were studied at the glycopeptide level by methylation analysis and 500-MHz¹H-NMR spectroscopy. Oligomannoside-type chains andN-acetyllactosamine-type chains are present in an approximate ratio of 31. While the oligomannoside-type chains show some heterogeneity in size (Man_5–8GlcNAc₂), theN-acetyllactosaminetype chains are exclusively bi-(2–6)-sialyl, bi-antennary in their structure.These observations on the carbohydrate moieties of -l-fucosidase substantiate our hypothesis [Overdijket al. (1986) Glycoconjugate J 3:339–50] with respect to the relationship between the oligosaccharide structure of lysosomal enzymes and their residual intracellular activity in I-cell disease. For the series of enzymes examined so far, namely, -N-acetylhexosaminidase, -l-fucosidase and -galactosidase, the relative amount ofN-acetyllactosamine-type carbohydrate increases, while the residual intracellular activity in I-cell disease tissue decreases in this order. The system which is responsible for preferentially retaining hydrolases with (non-phosphorylated) oligomannoside-type chains both in I-cells and in normal cells has yet to be identified.     

The lipopolysaccharide of the green sulfur bacterium Chlorobium vibrioforme f. thiosulfatophilum

The cell wall lipopolysaccharide of the green sulfur bacterium Chlorobium vibrioforme f. thiosulfatophilum was obtained by the phenol-chloroform-petroleum ether and the hot phenol-water methods, respectively. It contained mannose, glucose, galacturonic acid, glucosamine, glycine, and small amounts of rhamnose, galactose and glucuronic acid. In addition to d-glycero-d-mannoheptose, the corespecific constituents 2-keto-3-deoxyoctonate and l-glycero-d-mannoheptose were found. Polyacrylamide gel-electrophoresis in the presence of sodium deoxycholate gave no indication for the presence of O-specific repeating units. Degradation of the lipopolysaccharide required 10% acetic acid (100° C, 2 h). The lipid A moiety contained the total of glucosamine of the lipopolysaccharide as well as small amounts of 2,3-diamino-2,3-dideoxy-glucose. It was phosphate-free. The fatty acid spectrum comprised 3-OH-14:0, 3-OH-16:0, and iso-3-OH-18:0 besides little 12:0, 14:0 and 16:0. Hydroxylaminolysis and sodium methylate treatment revealed all of the three hydroxy fatty acids to be amidebound.Abbreviations DOC sodium deoxycholate - PAGE polyacrylamide gel-electrophoresis     

Manganese-binding proteins of the oxygen-evolving complex

The extrinsic 33-kDa protein (P33) was cross-linked covalently to the binding site on P33-depleted PSII preparations which is responsible for reconstitution of photosynthetic water oxidation after PSII preparations have been washed with 1 M CaCl2. Conditions were found in which more than half of the cross-linked protein complexes formed in the PSII preparations retained the ability to catalyze the oxidation of water. The complex is composed of the P33 cross-linked to the D1 and D2 proteins and a 34-kDa protein, which is present in lower abundance than the other three proteins. After solubilization of the membranes with SDS and purification by preparative SDS-PAGE, the complex retains bound manganese and can catalyze the conversion of H2O2 to O2. Calcium and chloride increased the catalase activity of the purified cross-linked complex while lanthanum or hydroxylamine abolished the activity. By use of the specific activity of the H2O2-dependent reaction to follow the extent of purification of the cross-linked complex, the most highly purified complex was determined to contain 0.34 microgram of manganese/180 micrograms of protein. The mole ratio of Mn/protein was calculated to range from 3.6 to 4.5 depending on the assumed stoichiometry of the protein subunits. The results presented here provide direct evidence that one or more of the three proteins that have cross-linked to the P33 are responsible for binding the manganese of the oxygen-evolving complex.     

The lipopolysaccharide of the phototrophic bacterium Ectothiorhodospira vacuolata

The lipopolysaccharide of Ectothiorhodospira vacuolata was obtained by the phenol-water procedure. It contained a 3-O-methyl-hexose, glucose, galacturonic and glucuronic acids. The finding of d-glycero-d-mannoheptose and 2-keto-3-deoxyoctonate (tentatively identified) suggested a core-structure. The lipid fraction of the lipopolysaccharide contained phosphate and both, 2,3-diamino-2,3-dideoxy-d-glucose and d-glucosamine. The major fatty acids were amine-bound 3-OH-10:0 and 3-OH-12:0 and esterbound 14:0 and 16:0 Sodium deoxycholate gel-electrophoresis, showing a single band only, indicated R-type character of the lipopolysaccharide of Ectothiorhodospira vacuolata.Abbreviations DOC sodium deoxycholate - GC/MS combined gasliquid chromatography - PAGE polyacrylamide gel-electrophoresis     

The effects of abscisic acid on growth and respiratory characteristics of potato tuber tissue discs

Incubation of potato tuber tissue discs on B5 medium supplemented with 1-naphtyl-acetic acid (NAA) led to callus formation, irrespective of the presence of kinetin; without NAA no callus formation occurred. Incubation in the presence of abscisic acid (ABA) reduced the increases in fresh weight and dry weight both in callus-forming and in non-callus-forming tissue. Mitochondrial respiration was lowered by ABA as well. The induction of the alternative, CN-resistant pathway was inhibited by the presence of ABA, especially in mitochondria from non-callus-forming tissue.The in vivo respiration of the callus-forming tissue was higher than that of the non-callus-forming tissue. Total respiration, cytochrome pathway activity and the capacity of the alternative pathway were all lowered in callus-forming tissue by treatment with ABA. The in vivo activity of the alternative pathway was low in all tissue types, especially after ABA-treatment. The slight stimulation by hydroxamates of the oxygen uptake of callus-forming tissue incubated on medium with NAA and ABA indicates the involvement of a hydroxamate-activated peroxidase in the oxygen uptake of this tissue; this peroxidase seemed not to participate in the oxygen uptake of the other tissues types.In non-callus-forming tissue the oxygen uptake of ABA-treated tissue was very low and almost completely resistant to the combined addition of inhibitors of both the cytochrome and the alternative pathway, indicating that the in vivo activity of the mitochondria in the oxygen uptake of the tissue was very low. The possible causes for this ABA-effect are discussed. In non-callus-forming tissue the treatment with ABA creates a situation which is comparable with that observed in intact potato tubers. This situation is characterized by a tissue respiration lower than that of the isolated mitochondria and an alternative pathway capacity that is low or absent.     

电损毁海马CA3区及连合前穹窿对大鼠血浆胰岛素水平...

Bilateral electrical lesioning of the hippocampal CA3 region (HCA3-EL) or anterior commissura hippocampi (ACHF-EL) caused marked elevations in plasma basal levels of insulin. 2 weeks later, fasting blood glucose levels were also augmented with decreased glucose tolerance. In contrast, the secretory response of pancreatic B cells to glucose stimulation was markedly enhanced. Following intravenous glucose tolerance test (IVGTT), the relative amounts of glucagon-like and insulin-like immunoreactants were reduced in the pancreatic islets of both HCA3-EL and ACHF-EL rats in comparison with the controls. In the HCA3-EL group, the relative amounts of somatostatin-like immunoreactants and gross numbers of such immunostained cells in islets were also decreased as compared with the control. No difference was seen in pancreatic-polypeptide-like immunoreactivities as assessed by immunohistochemistry plus microphotometry method. The above results suggest strongly that HCA3 and ACHF exert a tonic inhibitory action on the insulin secretion in the rat.     

The effect of copper toxicity on the contents of nitrogen compounds in Silene vulgaris (Moench) Garcke

The effect of copper on the uptake of nitrogen and the tissue contents of inorganic nitrogen, amino acids and proteins were studied in cooper-sensitive Silene vulgaris (Moench) Garcke, grown at different nitrogen sources (NH₄ ⁺ or NO₃ ^-). All the toxic copper levels tested, i.e. 4, 8, 16 M Cu²⁺, strongly inhibited the uptake of nitrogen, especially of NO₃ ^-, and decreased the content of NO₃ ^-, amino acids and proteins. Especially at 4 and 8 M Cu²⁺, NH₄ ⁺ accumulated in the plants, suggesting that the conversion of NH₄ ^- into amino acids was inhibited.     

活性氧对巨噬细胞呼吸爆发影响及云芝多糖的保护作用

用化学发光法观察到叔丁基氢过氧化物对培养的小鼠腹腔巨噬细胞呼吸爆发有强烈的抑制作用。云芝多糖经腹腔注射后,能增强巨噬细胞呼吸爆发功能对叔丁基氢过氧化物损伤的抵抗力。云芝多糖处理的巨噬细胞谷胱甘肽过氧化物酶基础活力显著提高,在叔丁基氢过氧化物作用下,云芝多糖处理的巨噬细胞仍有较高的谷胱甘肽过氧化物酶活力。说明巨噬细胞的免疫功能与谷胱甘肽过氧化物酶活力有关,非特异性免疫多糖可提高细胞抗氧化能力,减轻活性氧损伤作用。