鄱阳湖水生植被

本文列出了鄱阳湖98种水生维管束植物的名录,叙述了水生植被的分布。鄱阳湖水生植被面积为2262平方公里,占全湖总面积的80．8％。湖中植被呈不规则环带状分布,并可划分为湿生、挺水、浮叶和沉水4个植物带,9个主要植物群丛。并研究了鄱阳湖水生植被的演变及发展趋势和湖水位的季节性变化对植被的影响。     

细菌(Pseudomonas maltophilia)之绒毛膜促性腺激素(hCG)结合物质之研究

 细菌(Pseudomonas moltophilia)与hCG及LH有特异的亲和力,实验发现,细菌之生长曲线与hCG结合活性成平行关系,96小时达高峰,细菌之培养液中含有可溶性结合蛋白,该蛋白经硫酸铵沉淀(80％饱和度)、Sephadex G-100柱层析、DEAE-纤维素柱0.5mol/L NaCl梯度洗脱,再过Sepharose CL-AB柱,收集之活性部分经SDS电泳测得其分子量为70,000,凝胶层析测Stokes radius为41A,Schiff氏染色未见着色带。     

Survival of Shigella in Sewage: II. Effect of Glycerol on Shigella flexneri and Shigella Bacteriophage1

Glycerol (30%) inhibited or delayed the adsorption of Shigella bacteriophage on its host organism, S. flexneri II; glycerol also inhibited or delayed the burst of phage, whether or not adsorption was carried out in the presence of glycerol. Studies of the mechanisms of these effects showed that viscosity and osmotic shock probably were not responsible for either phenomenon. The inhibition of adsorption, however, was proportional to the concentration of glycerol, and appeared to be a function of the hydroxyl groups on the glycerol molecule. The inhibition of burst seemed to be related to the osmotic pressure outside the bacterial cells.     

Ornithine lipid of Mycobacterium tuberculosis: its distribution in some slow- and fast-growing mycobacteria

An ornithine-amide lipid is present in Mycobacterium tuberculosis. Its structure was established by a combination of chemical analysis and mass spectrometry. 3-Hydroxyoctadecanoic and 3-hydroxyeicosanoic acids (and homologues) were found to be linked through an amide bond to the alpha-amino group of L-ornithine, the hydroxyl group of the fatty acid being esterified mainly by tuberculostearic acid (10-methyloctadecanoic acid). This ornithine-amide lipid was detected in several other slow-growing pathogenic mycobacteria by thin layer chromatography, but not in an avirulent strain (H37 Ra) of M. tuberculosis. In each case mass spectrometry showed that all the structures were identical, thus revising an earlier reported structure for the lipid from M. bovis.     

Common denominators in the etiology and pathology of visceral lesions of cystic fibrosis and Keshan disease

The common denominator of a unique disseminated multi-focal milliary myocardial hyaline necrosis and fibrosis in Keshan disease (KSD) and cystic fibrosis (CF) and a commonality of the affected age groups of fetuses and preschool children led to the review of existing KSD autopsy material to search for pancreatic and hepatic lesions considered pathognomonic for CF. Pancreatic lesions considered pathognomonic for CF were found in 595, or 35% of 1700 documented cases of KSD. The pancreatic lesions were limited to tissues of fetuses and preschool children. Adults dying of KSD had diagnostic lesions limited to the cardiovascular system, liver, and skeletal muscle. Varying degrees of focal biliary cirrhosis were identified in 850, or 50% of the KSD autopsies, and 85, or 5% developed severe lobular cirrhosis. The common denominator in CF and KSD appears to be a primary or induced secondary selenium deficiency in age-susceptable humans, prenatally at or around 22 wk of fetal life, during early postnatal life, or during the rapid-growth preschool years. The basic difference between the natural history of CF and KSD is that the selenium deficiency is totally environmental in KSD and appears to be the result of a maternal malabsorptive syndrome or an abnormality of selenium transfer in CF.     

黄臀鹎禁食和夜间能量物质消耗的研究

本文报道分布于昆明地区的黄臀鹎Pycnonotus xanthorrhous在禁食和四季夜间能量物质——脂肪、蛋白质和糖的消耗情况。结果表明,在人为禁食条件下黄臀鹎的存活时间仅19小时,死亡时躯脂降低79％,去脂飞翔肌干重降低46％,肝糖降低96％。在夜间黄臀鹎消耗大量的储存脂肪,并以冬季的消耗量最大。肝糖提供的能量极少。在繁殖期和换羽期,储存的飞翔肌蛋白质在夜间大量分解以提供鸟体的需要。     

Time-Dependent Increase in Protein Phosphorylation Following One-Trial Enhancement in Hermissenda

Abstract: One-trial conditioning of the nudibranch mollusk Hermissenda produces short- and long-term changes in excitability (enhancement) of identified sensory neurons. To investigate the biochemical mechanisms underlying this example of plasticity, we have examined changes in protein phosphorylation at different times following the in vitro conditioning trial. Changes in the incorporation of ³²PO₄ into proteins were determined using two-dimensional polyacrylamide gel electrophoresis, autoradiography, and densitometry. Conditioning resulted in increases in levels of several phosphoproteins, five of which, ranging in apparent molecular mass from 22 to 55 kDa, were chosen for analysis. The increased phosphorylation of the 46- and 55-kDa phosphoproteins detected 2 h postconditioning was significantly greater than the level of phosphorylation detected in an unpaired control group, indicating that long-term enhancement is pairing specific. Statistically significant increases in phosphorylation as compared with the control group that received only light were detected immediately after conditioning (5 min) for the 55-, 46-, and 22-kDa phosphoproteins, at 1 h for the 55- and 46-kDa phosphoproteins, and at 2 h for the 55-, 46-, and 22-kDa phosphoproteins. The 46- and 55-kDa phosphoproteins are putative structural proteins, and the 22-kDa phosphoprotein is proposed to be a protein kinase C substrate previously identified in Hermissenda following multitrial classical conditioning. Time-dependent increases in protein phosphorylation may contribute to the induction and maintenance of different memory stages expressed in sensory neurons after one-trial conditioning.     

A SPOROPHYTE CELL WALL PROTEIN OF THE RED ALGA PORPHYRA PURPUREA (RHODOPHYTA) IS A NOVEL MEMBER OF THE CHYMOTRYPSIN FAMILY OF SERINE PROTEASES1

A complementary DNA (cDNA) clone from a Porphyra purpurea (Roth) C. Agardh sporophyte-specific subtracted cDNA library was found to encode a protein similar to serine proteases of the chymotrypsin class. The encoded protein contains a typical signal peptide and is particularly similar to chymotrypsins in the regions surrounding the active site residues and the activation site where cleavage of the propeptide occurs. In addition, the six cysteine residues characteristic of chymotrypsins are conserved. However, two of the three residues of the active site His/Asp/Ser charge relay triad have been replaced, indicating that the protein is unlikely to have peptidase activity. Northern hybridization confirmed that this cDNA is derived from an abundant, sporophyte-specific messenger RNA (mRNA). The presence of signal peptide on the encoded protein and the abundance of its mRNA suggested that this protein might be localized in the cell wall. Consequently, sporophyte cell walls were isolated and a major protein having a molecular weight similar to that estimated for the encoded protein was purified. N-terminal sequence analysis indicated that this cell wall protein is identical to that encoded by the cDNA with the amino terminus of the mature protein beginning at the activation site. This cell wall structural protein appears to have evolved from a chymotrypsin-like progenitor but has been adapted to bind cell wall proteins and/or polysaccharides rather than to cleave proteins.     

细胞分裂素生物合成基因在调节一组烟草病理相关蛋白基因表达中的作用

对一组病理相关蛋白基因在烟草 ( N icotiana tabacum cv. Wisconsin 38)中的表达情况进行了研究 ,包括 :碱性几丁质酶、β- 1 ,3-葡萄糖苷酶、渗透蛋白及伸展蛋白。RNA杂交实验表明在正常烟草植株中上述 4个基因具有发育和器官专一性的表达。在含有细胞分裂素生物合成基因的转基因烟草丛生芽中 ,这 4个基因的表达受过量合成的内源细胞分裂素和载体效应的共同调节 ,细胞分裂素降低这些基因的表达 ,而载体效应则促进它们的表达。热激处理也明显降低这 4种基因的表达水平。上述结果表明这些病理相关蛋白基因具有复杂的调控系统