海洋细菌B177的鉴定及活性物质研究

运用卤虫和玉米纹枯病菌为筛选靶标,从中国南海海泥的94株细菌中分离筛选到1株具有杀虫、抗菌活性的海洋细菌B177菌株。卤虫和玉米纹枯病菌筛选模型测定结果表明,当PSA为发酵液时,LD50值最低,为1.3μg.mL-1;当滤纸片加20μL(5mg.mL-1浓度)发酵粗提取物溶液时,抗玉米纹枯病菌抑菌圈直径可达26mm。对B177的形态特征、培养特征、生理生化特征、16S rDNA序列进行了系统的研究,鉴定其为Micrococcus yunnanensis,其16S rDNA GenBank登录号为HQ439904。对其活性物质进行初步分离纯化研究。     

Involvement of Bacillus licheniformis and Micrococcus kristinae During Ripening of Salt Fermented Indian Shad (Tenualosa ilisha)

ABSTRACT

“Lona ilish” is a salt fermented fish product prepared exclusively from fatty Indian shad (Tenualosa ilisha). Despite the presence of salt and metals coming from the container used for fermentation, rancidity is not observed as long as the products are kept immersed in the fermenting brine. To understand the technical principles of this indigenous preservation method, the traditional preparation was followed along with analyses of chemical and microbiological changes. The biochemical and microbiological changes were followed at 15 day intervals during the fermentation period of 150 days. From the 45th day of fermentation onwards, the microbial flora in the product was composed of only two species, tentatively identified as Bacillus licheniformis and Micrococcus kristinae. Because Bacillus licheniformis showed some atypical biochemical reactions, it was tentatively identified as Bacillus licheniformis var. III. These two bacterial species either singly or collectively were involved in the fermentation process.     

藤黄微球菌AD3的阿特拉津降解基因检测与分析

为了获得高效稳定的阿特拉津基因,分离出更多的阿特拉津降解菌,试验采用PCR基因扩增和氮源利用方法,对AD3菌株的阿特拉津降解基因进行了检测和测序,并与其他菌株阿特拉津降解基因的序列进行了比较。结果表明：Micrococcus luteus AD3菌株含有阿特拉津降解基因trzN,atzB,atzC和atzDEF。其中trzN基因中心区的序列与Arthrobacter sp.TC1的trzN完全相同,atzB和atzC基因中心区的序列与Pseudomonas sp.ADP的atzB和atzC完全相同。AD3菌株能以氰脲酸为唯一氮源生长,Micrococcus luteus AD3菌株能将阿特拉津彻底降解成CO2和NH3。     

基于高效解磷菌的煤矸石肥料制备及其应用潜力分析

从风化的煤矸石中分离筛选出一株具有解磷能力的细菌菌株GZU-Mic02,经鉴定,为藤黄微球菌(Micrococcus luteus)。利用该菌株和巨大芽孢杆菌(Bacillus megaterium)菌株ACCC1011分别解离煤矸石制备肥料,与没有处理的煤矸石样品相比,制备的煤矸石肥料的碱解氮、有效磷和速效钾含量都大幅提高。其中,经GZU-Mic02菌株处理的煤矸石肥料相比经巨大芽孢杆菌处理的煤矸石肥料具有更高的有效磷和碱解氮含量,而后者的速效钾含量更高。采用烟草盆栽试验验证制备的煤矸石肥料的肥效,结果表明,分别施用2种煤矸石肥料培育25 d后,烟草的株高、茎围和叶片大小均优于不施用肥料的对照组,且以用GZU-Mic02菌株制备的煤矸石肥料的效果更佳。     

牛肉发酵香肠成熟过程中菌相变化的研究

研究了在不同发酵剂作用下，发酵香肠成熟过程中微生物的构成和数量变化。在发酵香肠的成熟过程中，乳酸菌一直是优势菌，在第8天达到最大，即10^8cfu／g以上，微球菌和葡萄球菌与乳酸菌的变化趋势基本一致，但远低于乳酸菌。     

Comparison of methods for routine separation of coagulase-negative staphylococci from micrococci isolated from sheep

A total of 176 Gram-positive, catalase positive cocci strains, isolated from sheep were studied by different routine tests for the differentiation of staphylococci and micrococci, comparing their validity and usefulness. By glucose fermentation and growth in the anaerobic portion of thioglycolate 85 and 73.6% respectively of coagulase negative staphylococci were misclassified as Micrococcus spp. Susceptibility to lysostaphin was an adequate test for the differentiation of the strains. Atypical results in the production of acid from glycerol/erythromycin were obtained in 11.8% of the coagulase negative strains and 16.7% of micrococci. The combined use of the selective media furazolidone agar and Schleifer and Krämer medium resulted in a fast and useful separation of ovine staphylococci and micrococci. The bacteriolytic activity misclassified 32.2% of the coagulase negative strains.     

Comparison of Different Agar Diffusion Methods for the Detection of Antimicrobial Residues in Slaughter Animals

The different agar diffusion methods were compared using antibiotic and sulphonamide-impregnated filter-paper discs and the kidneys of healthy and emergency-slaughtered pigs and cows after slaughter.No method used seemed to be sensitive to all antimicrobial drugs preimpregnated onto discs. Tetracycline yielded a greater zone of inhibition at pH 6 than at pH 8 and aminoglycosides, erythromycin, polymyxin B and lin cornycin at pH 8 than at pH 6. It therefore seems necessary to use different pHs (6 and 8). The addition of trimethoprim to the medium is necessary for the detection of sulphonamides. Bacillus subtilis BGA used as the test organism was more sensitive to sulphonamides on the “Test agar for the inhibitor test” containing trimethoprim than on the “Iso-Sensitest agar” also containing trimethoprim. The addition of trimethoprim to “Test agar for the inhibitor test” is recommended at pH 8 but not at pH 6 because false-positive cases (with inhibition zones > 2 mm) were observed at pH 6 with trimethoprim on the kidneys of healthy pigs.     

Effect of organic acids on the microbial quality of Taiwanese-style sausages

The effects of organic acids on the microbial quality of Taiwanese‐style sausages were studied. Pork meat from a Taiwan retail market was decontaminated with various organic acids (citric, lactic and tartaric acid), then, the raw meat was used to make Taiwanese‐style sausages and stored from 0 to 40 days at 4°C. The total plate counts, lactic acid bacteria, Micrococcus, Listeria monocytogenes, Hunter‐L and Hunter‐a values were determined. The total plate counts of the control group were initially greater than those of the treated groups. Higher incidence rates of L. monocytogenes in the products were obtained from the control group, but were not detected in the treated groups during storage. Lactic acid bacteria counts following the lactic acid treatment were lower than those of the other groups. Micrococcus counts of the controls increased by 0.6–1.2 log₁₀ colony‐forming unit (CFU)/g greater than those of treated groups throughout storage at 4°C. The light color (L‐value) of the control group gradually decreased during storage. Pork meat dipped in various organic acids was found to be suitable to extend the shelf‐life and improve the microbiological quality of Taiwanese‐style sausages.     

西瓜枯萎病土壤拮抗菌的筛选(英文)

[Objective] The aim of this study was to screen bacteria strains with stable antagonistic effect against watermelon fusarium wilt from soil and investigate the biological control of watermelon fusarium wilt by applying the antagonistic bacteria strains into soil.[Method] Actinomycete strains,fluorescent bacteria strains and bacillus strains were isolated from soil samples by the dilution-plate method,then its resistance was screened respectively by the improved confront culture method after colonies were purified.Finally,bacteria strains with better antagonistic effect were identified.[Result] 29 bacteria strains with stable antagonistic effect against watermelon fusarium wilt were screened from 39 soil samples,which contained 15 fluorescent bacteria strains,5 bacillus strains and 9 actinomycete strains.Furthermore,three antagonistic bacteria strains of FM2,FM3 and FM4 with the strongest antagonism were identified primarily.[Conclusion] According to cultural characteristics,morphological observation,biochemical and physiological tests,FM2 belongs to bacillus subtilis,while FM3 and FM4 belong to micrococcus.     

Misidentification of soil bacteria by fatty acid methyl ester (FAME) and BIOLOG analyses

 Fatty acid methyl ester (FAME) analysis is commonly used by soil scientists as a sole method for identifying soil bacteria. We observed discrepancies with this method for identifying certain species of bacteria. Therefore, we used carbon substrate oxidation patterns (BIOLOG) and some simple physical and chemical tests to determine the extent of these discrepancies. Identification with FAME profiles gave false positives for Arthrobacter globiformis, Micrococcus kristinae, and M. luteus, and identification with BIOLOG patterns gave a false positive identification for A. globiformis. A visual check and Gram stain are recommended when FAME analysis identifies soil isolates as M. kristinae or M. luteus, and an additional spore formation test is recommended when FAME and BIOLOG analyses identify isolates as A. globiformis. Received: 14 January 2000