Electrophoretic Variants of Intracellular Catalase of Different Candida Species

Intracellular and extracellular catalases of different species of Candida were investigated using different culture media. All the Candida strains produced intracellular catalase, whose enzymatic activity was detected by non-denaturating polyacrylamide gradient (4-30%) gel electrophoresis. The cell extracts presented a major 230 kDa catalase band and in some strains variants of catalase with different molecular weights were detected. Candida catalase activity was not affected by heating at 50 degrees C and incubation with beta-mercaptoethanol, but treatment with sodium dodecyl sulphate inhibited or reduced enzymatic activity. Extracellular enzyme activity was not detected in any of the culture filtrate extracts tested.     

Virulence of Yersinia ruckeri serotype I strains is associated with a heat sensitive factor (HSF) in cell extracts

Cell extracts of Yersinia ruckeri (serotype I) were examined by SDS-PAGE and Western blotting. An unusual band, termed heat-sensitive factor (HSF) was observed in extracts of virulent strains only. It is thought to be lipid in nature; no differences could be detected in the region of the band in protein profiles of virulent and avirulent strains. When trout were infected either by intraperitoneal injection or bath immersion, mortalities occurred only with HSF+ strains. The HSF appears to be an important virulence determinant of Y. ruckeri.     

Characterization of fimbriae extracts from porcine enterotoxigenic Escherichia coli strains carrying F6 (987P) antigen.

Fimbrial extracts from porcine enterotoxigenic Escherichia coli (ETEC) strains carrying F6 (987P) intestinal colonization factor antigen wereobtained using the thermal shock method. The extracts were analyzed by SDSPAGE and immunoblotting using different fimbriae-specific antisera. Two major protein bands with molecular masses of 17.5 and 21.9 kDa were detected. The 21.9-kDa band was identified as the major subunit of F6 fimbrial antigen in strains of serogroups O9 and O141. The 17.5-kDa band was associated with porcine strains of serogroups O9 and O20.     

Antibiotic properties of the strains of the basidiomycete Lentinus edodes (Berk.) sing]

Antibiotic properties of the extracts from the fermentation broth and mycelium of 15 strains of the edible and medicinal basidiomycete L. edodes were studied and it was shown that the extracts were active against grampositive and gramnegative bacteria, yeasts and mycelial fungi, including dermatophytes and phytopathogens. The strains differed by the set of the organisms susceptible to the action of the extracts. Strains of L. edodes combining marked antibiotic properties and high yields of water soluble polysaccharides were screened. The active compounds were detected by preparative TLC. Two of them were identified with UV- and mass spectrometry as lentinamycin B and erytadenine (lentinacin). Lentinamycin B was found to be the main component responsible for the antibiotic activity of the L. edodes strains.     

Genetic and physiological characterization of the purine salvage pathway in the archaebacterium Methanobacterium thermoautotrophicum Marburg.

The enzymes involved in the purine interconversion pathway of wild-type and purine analog-resistant strains of Methanobacterium thermoautotrophicum Marburg were assayed by radiometric and spectrophotometric methods. Wild-type cells incorporated labeled adenine, guanine, and hypoxanthine, whereas mutant strains varied in their ability to incorporate these bases. Adenine, guanine, hypoxanthine, and xanthine were activated by phosphoribosyltransferase activities present in wild-type cell extracts. Some mutant strains simultaneously lost the ability to convert both guanine and hypoxanthine to the respective nucleotide, suggesting that the same enzyme activates both bases. Adenosine, guanosine, and inosine phosphorylase activities were detected for the conversion of base to nucleoside. Adenine deaminase activity was detected at low levels. Guanine deaminase activity was not detected. Nucleoside kinase activities for the conversion of adenosine, guanosine, and inosine to the respective nucleotides were detected by a new assay. The nucleotide-interconverting enzymes AMP deaminase, succinyl-AMP synthetase, succinyl-AMP lyase, IMP dehydrogenase, and GMP synthetase were present in extracts; GMP reductase was not detected. The results indicate that this autotrophic methanogen has a complex system for the utilization of exogenous purines.     

群体感应抑制活性海洋细菌的筛选与鉴定

从黄海青岛海域海洋污泥中分离纯化微生物菌株,然后采用紫色色杆菌(Chromobacterium violaceum) 为指示菌株,检测其代谢产物的群体感应(Quorum sensing) 抑制活性,并对具有抑制功能的细菌菌株进行16S rDNA分子鉴定及生理生化特征分析.结果表明,1株蜡样芽孢杆菌和1株水莱茵海默氏菌具有较强的细菌群体感应抑制活性,分别命名为Bacillus cereus QSI01和Rheinheimera aquimaris QSI02.从海洋环境中筛选的具有细菌群体感应抑制活性的菌株,为以致病菌群体感应系统为靶点的新型药物的研发提供了菌种资源.     

An electron spin resonance study of oxyradical generation in superoxide dismutase- and catalase-deficient mutants of Escherichia coli K-12

The response of superoxide dismutase- and catalase-deficient strains of Escherichia coli to redox active compounds was examined by electron spin resonance. Levels of radicals formed in response to pyocyanine in situ were extremely low and were found to be predominantly extracellular, even in a strain completely deficient in both superoxide dismutase and catalase. In cell-free extracts of superoxide dismutase-minus strains incubated with NADPH and pyocyanine, the primary accumulating radical was the superoxide anion (O2-), although low levels of the hydroxyl radical (.OH) were also detected. In contrast, extracts from strains lacking catalase were found to accumulate higher levels of hydroxyl radicals.     

Chitinolytic activity of actinomycetes from a cerrado soil and their potential in biocontrol

The crude enzyme extracts from five actinomycetes selected from a cerrado soil presented very good endochitinolytic activity when compared to a commercial chitinase. Exochitinase and chitobiase activities were also detected. They were identified as Streptomyces, but could not be characterized to species level, probably corresponding to new ones. The crude extracts, obtained from growth on fungal mycelium plus chitin of three of the strains, have shown a very pronounced activity against phytopathogenic fungi. In tests using growing cells, all five strains were active. These data suggest that these strains are potential biocontrol agents.     

Evaluation of Sclerotinia sclerotiorum as a potential mycotoxin producer on soybeans

Solvent extracts of Sclerotinia sclerotiorum sclerotia were nontoxic to mice and chicken embryos; psoralens were not detected. Solvent extracts of soybeans inoculated with 10 strains of S. sclerotiorum were toxic on injection but nontoxic on per os administration to mice. The presence of chlorinated hydrocarbons in the soybeans may partially help explain toxicity by intraperitineal injection.     

Evaluation of Sclerotinia sclerotiorum as a potential mycotoxin producer on soybeans.

Solvent extracts of Sclerotinia sclerotiorum sclerotia were nontoxic to mice and chicken embryos; psoralens were not detected. Solvent extracts of soybeans inoculated with 10 strains of S. sclerotiorum were toxic on injection but nontoxic on per os administration to mice. The presence of chlorinated hydrocarbons in the soybeans may partially help explain toxicity by intraperitineal injection.     

Immunoelectrophoresis to detect differences between strains of Candida albicans

Summary Aqueous extracts of two parental strains ofCandida albicans and two mutants obtained from these strains were studied through immunoelectrophoresis and differential staining for protein and polysaccharide fractions after electrophoresis. Differences in antibody-antigen reactions, and protein and polysaccharide fractions could be detected between these strains. These differences reflected changes in synthesizing ability and genetic information inherent in these yeast cells.     

An Examination of Corynebacterium spp. by Gel Electrophoresis

S ummary . The cell free extracts of 24 organisms of the genus Corynebacterium were examined by starch gel electrophoresis for esterase, catalase and peroxidase activity. The protein components of eleven of these extracts were also detected after electrophoresis in polyacrylamide gel. The results indicate a separation of the members of the genus into distinct subgroups comparable to those obtained by grouping strains according to habitat.     

A characteristic phenolic glycolipid antigen from Mycobacterium haemophilum

A characteristic phenolic glycolipid was detected, by thin layer chromatography, in non-polar lipid extracts of nine representative strains of Mycobacterium haemophilum . The lipid was a specific antigen that reacted strongly with serum raised against whole cells of M. haemophilum. Sera from six other mycobacterial strains were tested but only that from Mycobacterium kansasii give a weak reaction.     

含有禽网状内皮组织增生病病毒基因组片段的天然重组禽痘病毒的研究

将国内5个不同生产厂家来源的禽痘弱毒疫苗株和1株禽痘野毒株在鸡胚成纤维细胞(CEF)上连续传5代,用禽网状内皮组织增生病病毒(Reticuloendotheliosis virus,REV)特异性的单克隆抗体进行间接免疫荧光试验(Immunonuoreseellee assay,IFA),均检测不到传染性REV。但以6株禽痘病毒(FPV)感染的第2代和第5代细胞基因组提取物为模板,通过PCR均能扩增出REV的长末端重复序列(LTR)和囊膜蛋白(env)基因片段。用特异性核酸探针作分子斑点杂交(Dot blot),结果显示所扩增的PCR条带为特异的REV—LTR和REV—env)基因片段。实验结果表明,国内的一些痘病毒疫苗和野毒株基因组中,已稳定地整合进了REV的基因组成分。     

Factors affecting the toxicity of diazinon to Musca domestica L

Processes affecting the toxicity of diazinon to a susceptible and a resistant strain of houseflies were examined. More evidence was obtained to show that slower penetration of diazinon through the integument of resistant flies is a cause of resistance. Small amounts of two decomposition products were found in both strains. The decomposition mechanisms, in these strains were differently distributed and, although detoxication of diazinon in the two strains is quantitatively similar and small, it may contribute to resistance. Traces of diazoxon were detected when diazinon was incubated with tissue extracts of either strain. Tissue extracts of resistant, but not of susceptible, flies decomposed significant amounts of diazinon in 1 hr. and the ability to decompose diazoxon seems to be an important cause of resistance. Tissues of both strains sorbed diazinon from aqueous solution similarly; the quantities sorbed were large and suggest that sorption may increase the amount of poison needed inside the insects to kill, by between five and forty times.     

A comparison of the isoenzymes, soluble proteins, polypeptides and free amino acids from ten isolates of Trypanosoma evansi.

1. Soluble extracts from different strains of Trypanosoma evansi were compared by several analytical procedures. 2. No isoenzymic differences were detected. 3. Some clear intraspecies differences in protein isoelectric points, in polypeptide sizes and in free amino acid contents were found.     

胡桃楸提取物对白色念珠菌生长的抑制作用

目的 探讨胡桃楸提取物对白色念珠菌生长的抑制作用。方法 以NCCLS方案检测胡桃楸提取物和伊曲康唑（ICZ）、氟康唑（FCZ）、两性霉索B（AMB）和5-氟胞嘧啶（5-FC）对133株白色念珠菌体外生长抑制作用。结果 标准菌株JC1A的MIC结果表明胡桃楸提取物对白色念珠菌的抗菌作用相当于FCZ,略低于ICZ、AMB和5-FC;临床分离株对ICZ和FCZ的耐药率很高,对胡桃楸提取物的耐药率较低。结论 胡桃楸提取物对白色念珠菌生长有强力抑制作用。     

Immunochemical analysis of water-soluble antigen complexes isolated from typing strains of Pseudomonas aeruginosa of different O-serogroups

Cross immunoelectrophoresis in agarose and immunodiffusion in agar gel were used to carry out the immunochemical analysis of water-soluble antigenic components isolated from P. aeruginosa of different O-serogroups (according to Lanyi's classification). Immunodiffusion revealed the presence of 1--3 common antigens and 1 specific O-antigen in aqueous extracts. Experiments with the use of cross immunoelectrophoresis indicated that 1--12 common antigens could be detected in aqueous extracts. The reference preparation, produced on the basis of the cell mixture of 9 P. aeruginosa strains, contained up to 47 antigenic components, many of them being common to the strains of different O-serogroups (immunotypes).     

Antagonistic activity of Staphylococcus siderophores and chemical biocides against Bacillus subtilis in a paper-machine environment

The antagonistic potential of nonpathogenic Staphylococcus strains against Bacillus subtilis wild and type strains were studied under conditions simulating a paper- and board-machine environment. The antimicrobial activity was measured by growth inhibition in an automated turbidimeter. The antagonistic potential was compared with that of generally used chemical biocides in a paper- and board-machine environment. The siderophore-containing extracts of Staphylococcus strains significantly inhibited vegetative growth of B. subtilis and delayed the germination of spores both in synthetic and in white-water media. The mill strains were more resistant than type strain against Staphylococcus siderophores and against chemical biocides. The Staphylococcus siderophore-containing extracts did not interfere with the bacteriostatic effect of chemical biocides, but no synergy was detected. The results indicate the potential for application of Staphylococcus siderophore-containing extracts as biocontrol agents in paper- and boardmachine environment. Received 2 January 1998/ Accepted in revised form 4 December 1998