芽孢杆菌BI1的鉴定及其抑菌性研究

目的 对本实验室分离得到芽孢杆菌B11进行鉴定.方法 将该菌株的16S rDNA基因序列与GeneBank中已鉴定的16S rDNA序列对比,并结合生理生化实验综合分析.结果 菌株B11与枯草芽孢杆菌亲缘关系最为接近,16S rDNA基因相似性达到99.6%,生理生化实验结果与标准枯草芽孢杆菌一致.结论 将芽孢杆菌B11鉴定为枯草芽孢杆菌.     

豆豉纤溶酶产生菌发酵条件研究

对从豆豉中筛选到的一株纤溶酶产生菌--枯草芽孢杆菌HGD107进行发酵产酶条件研究.在最适发酵条件下,该菌株产豆豉纤溶酶酶活达到尿激酶3643u/ml发酵液.     

中成药中的芽孢杆菌鉴定

目的：随机取抽验细菌数超限的中成药20批,对培养检出的芽孢相菌进行鉴定,方法：根据培养检出的16株芽孢杆菌的形态,生理生化,碳源及氮源利用等32项特征鉴定到种。结果与讨论：16株芽孢杆菌中,巨大芽孢杆菌3株,枯草芽孢杆菌8株,环状芽孢杆菌3株,蜂房芽孢杆菌1株,球形芽孢杆菌1株,从中成药检出以上芽孢杆菌,说明中成药现行幅射剂量可能不足,或是保存期间再次受微生物污染,具体原因待进一步探讨,建议今后的《中国药典》,在[微生物限度]检查项目中,应当考虑增加有关芽孢杆菌的质控内容。     

豆豉纤溶酶生产工艺研究

以筛选得的纤溶酶产生菌——枯草芽孢杆菌HGD107进行15L发酵罐生产豆豉纤溶酶，产物经离心、D392型树脂脱色、盐析、超滤等操作纯化，制得冻干豆豉纤溶酶产品，其比活力为530．6u／mg，纯化倍数11，活性回收率65．7％。     

一株产脂肽类抗生素bacillopeptin A深海芽孢杆菌的筛选与鉴定

目的 筛选从中国南海深海3601m的海泥样品中分离得到的细菌,获得一株芽孢杆菌SH-B74,分离其产生抗植物病原真菌脂肽类化合物,并进行菌种鉴定.方法 使用酸沉淀、快速柱色谱、SPE和半制备反高效液相色谱技术分离发酵液中的脂肽类纯化合物,采用形态、生理生化特性和16S rDNA基因序列分析相结合方法鉴定菌株.结果 分离纯化得到一种拮抗植物病原真菌的脂肽类纯化合物bacillopeptin A,分子量为1020.6Da;菌株经鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens).结论 该菌株对玉米纹枯病等多种植物病原真菌具有拮抗作用,代谢产物bacillopeptin A对苹果干腐病菌具有良好的拮抗效果.显示了该菌及其代谢产物在植物病原真菌的生物防治和土壤生物修复方面具有潜在研发价值.     

红海榄根际土壤中短小芽孢杆菌菌株DH-11的鉴定及其抗菌活性的分析

根据菌体的形态、生理生化特征以及16s rDNA序列分析结果,将一株分离自中国海南东寨港红树林保护区红海榄根际土壤的细菌菌株DH-11鉴定为芽孢杆菌属的短小芽孢杆菌(Bacillus pumilus strain DH-11)。菌株DH-11是一种革兰阳性短杆菌,大小约为(0.5～0.6)μm×(0.7～1.5)μm,卵圆形芽孢侧端生。其细胞中的主要脂肪酸为Iso-C15∶0和Anteiso-C15∶0,它们的含量占菌体总脂肪酸含量的47.49%和26.21%,其它脂肪酸还包括Iso-C17∶1(7.27%)、Anteiso-C17∶0(6.92%)、C16∶1 N Alcohol(3.45%)以及C16∶0(2.33%)等。与已报道的短小芽孢杆菌菌株B.pumilus ATCC 7061的不同之处在于:菌株DH-11不能利用木糖和甘露醇产酸,且硝酸盐还原呈阳性。进一步的研究显示:菌株DH-11在改良马铃薯培养基中培养时,获得的培养液及其提取浸膏不能抑制革兰阴性细菌Escherichia coli和Pseudomonas aeruginosus的生长,但对革兰阳性菌Staphylococcus epidermidis、Staphy-lococcus aureus、Bacillus subtilis和Sarcina lutea的生长具有一定的抑制作用:其中发酵液浸膏1和浸膏2对上述菌株的最低抑菌浓度(MIC)分别为500.0和250μg/mL,浸膏2还可抑制真菌Candida albicans的生长,其MIC为500μg/mL。     

抗流感病毒H1N1海绵放线菌的筛选及菌株HA10201的鉴定

目的从海绵中分离筛选具有抗H1N1活性的放线菌,并对活性菌株HA10201进行鉴定。方法采用CPE和MTT方法对从海绵中分离的放线菌进行抗H1N1活性筛选,对活性较强的菌株HA10201进行形态学和生理生化特性研究,测定其16SrDNA序列并进行系统发育分析。结果菌株HA10201发酵液稀释20倍后对H1N1抑制率达68.1%,HA10201与Streptomyces roseorubens的形态和生理生化特征最为接近,且与其16SrDNA序列相似性为99.40%,且在发育树上聚为一个分支。结论菌株HA10201鉴定为S.rose-orubens,其发酵液具有较强的体外抗H1N1活性,值得进一步研究。     

苔藓内生菌Bacillus megaterium z12的分离、鉴定和抗菌活性筛选

目的从无纹紫背苔(Plagiochasma intermedium)叶片中分离筛选出一株具广谱抗菌活性的内生菌z12。方法根据菌落和细胞形态、生理生化特性,以及16S rDNA序列对内生细菌z12进行了分析鉴定,并研究了它对14种供试菌株的抑制作用。结果经分析鉴定该菌属于巨大芽孢杆菌(Bacillus megaterium)。抑菌实验表明,内生细菌z12对7种供试菌都有不同程度的抑制作用,对金黄色葡萄球菌(Staphylococcus aureus)和白念珠菌(Candida albicans)的抑制作用较强。研究了z12菌株粗提物对水稻纹枯病原菌(Corticium sasakii)的抑制作用。结论该菌株具有开发成农用抗生素的价值。     

抗甲型流感H1N1病毒红树林内生放线菌的筛选及菌株HA12210的鉴定

目的对红树林内生放线菌进行抗H1N1病毒活性检测,并对具有较高活性的菌株HA12210进行鉴定。方法采用嗜杀酵母系统和CPE+MTT联合法模型对菌株发酵液进行抗H1N1病毒活性的初筛和复筛;对菌株HA12210进行培养和形态特征、生理生化特征的鉴定,测定其16SrDNA序列并进行系统发育分析。结果菌株HA12210发酵液稀释20倍后对H1N1病毒的抑制率达到73.2%。HA12210与Micromonospora marina JSM1-1T形态和生理生化特征接近,并与其16SrDNA序列相似性最高(99.70%),且在发育树上聚为同一分支。结论鉴定活性菌株HA12210为Micromonospora marina,本文首次报道了该菌株的抗H1N1病毒活性。     

4种药用植物内生放线菌的分离与初步研究

目的分离并研究具有抑菌活性的药用植物内生放线菌。方法使用高氏一号培养基定向筛选药用植物内生放线菌,采用滤纸扩散法评价分离菌株的抑菌活性,进而通过形态学、生理生化等特征的分析对其进行鉴定。结果共分离得到63株内生放线菌。对金黄色葡萄菌、表皮葡萄球菌、枯草芽孢杆菌、大肠杆菌、铜绿假单胞菌等表现出选择性抑菌作用的菌株有17株,其中Y6菌株抗菌谱较广、抑菌作用较强。初步鉴定结果表明Y6菌株是链霉菌属的一个成员。结论 Y6对金黄色葡萄球菌的抑菌效果较好。     

纤溶酶产生菌株BS-26的发酵工艺优化

目的对纤溶酶产生菌株BS-26发酵工艺进行优化。方法通过单因素试验和正交试验,确定了摇瓶发酵的最佳条件。结果该菌株产纤溶酶最佳的发酵条件为:3%糊精、1%酵母粉、0.02%CaCl2、0.07%MgSO4,初始pH7.0,接种量为6%,装液量为70/250(mL/mL),摇床温度37℃,转速180 r/min,发酵时间60 h,在该条件下产酶酶活可达593.03 U/mL,是原发酵培养条件下产酶活力的4.5倍。结论此发酵条件可以很好地提高纤溶酶的活力,为发酵规模的扩大奠定了基础。     

Cytotoxic potential of industrial strains of Bacillus sp

The cytotoxic potential of selected strains of Bacillus licheniformis, Bacillus amyloliquefaciens, and Bacillus subtilis, used in the production of industrial enzyme products, has been assessed. Cytotoxicity was determined in Chinese hamster ovary (CHO-K1) cells by measuring total cellular metabolic activity using the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Initially the MTT assay was validated against toxigenic strains of Bacillus cereus, to define the exact criteria for a toxigenic versus a nontoxigenic response. The assay proved sensitive to culture broths of both a diarrheagenic strain and an emetic strain of B. cereus. The enzyme-producing strains tested were nontoxic to CHO-K1 cells. Additionally it was demonstrated that our industrial strains did not react with antibodies against B. cereus enterotoxins by use of commercial antibody-based kits from Oxoid and Tecra. A short survey of the literature concerning the toxigenic potential of species within the subtilis group is included, as is a database search of known B. cereus enterotoxins against B. subtilis and B. licheniformis DNA sequences.     

1株抗耐甲氧西林金黄色葡萄球菌的土壤放线菌的分离与鉴定

目的:从土壤中分离与鉴定抗耐甲氧西林金黄色葡萄球菌(MRSA)的放线菌。方法:在改良的高氏Ⅱ号培养基上划线分离土壤放线菌,以MRSA作为受试菌株,测试抗菌活性,对具有抗菌活性的菌株进行16SrDNA种属鉴定。结果:获得拮抗放线菌1株(命名为Hu001),具有较强的抗MRSA的活性;并将16SrDNA序列提交GenBank数据库,(登录号为JQ689078),与同源细菌进行比对,得到其系统进化树;经鉴定16SrDNA序列与山丘链霉菌(Streptomycescollinus)NBRC12547株具有99%的同源性。结论:放线菌Hu001具有抗MRSA的活性,并根据16SrDNA序列测序将其初步归属于山丘链霉菌。     

微生物来源抗肿瘤先导化合物的靶向筛选研究

目的 寻找具有抗肿瘤活性的雷帕霉素结构类似物。 方法 以雷帕霉素细胞内结合蛋白RBP为靶标，运用营养依赖重组微生物工程菌筛选方法，从微生物的的次级代谢产物中筛选活性化合物；通过16S rDNA序列分析鉴定活性化合物产生菌；深层发酵制备活性物培养液并分离、纯化目标物；根据波谱检测及数据解析进行化合物结构鉴定并进行活性评价。结果 筛选获得1株活性菌株CY-365，经鉴定为放线菌链霉菌属，其代谢活性产物CY-365结构解析为15(S)-O-乙基雷帕霉素，与雷帕霉素具有相似的体外抗肿瘤活性。 结论 链霉菌CY-365经深层培养，主要代谢产物为具有抗肿瘤活性的15(S)-O-乙基雷帕霉素。     

豆乳凝固酶产生菌LD30的研究

目的从土壤中分离产豆乳凝固酶菌株,并研究其发酵条件和酶学性质。方法采用常规土壤分离方法和培养基。结果从广东、敦煌、吐鲁番等地得到的12份土壤样品中分离得到1株产豆乳凝固酶的菌株芽孢杆菌LD30。在给定的发酵条件下,豆乳凝固酶的产率达到600 U.L-1。酶学性质表明:该酶的最适反应温度为70℃,60℃保温1 h,残余酶活力为50%。在pH6.0~7.0内,酶活力稳定,最适酶反应的pH值为5.9。结论筛选到的产豆乳凝固酶菌株芽孢杆菌LD30具有较高的产酶活性,值得进一步深入研究。     

Antibacterial activity of cervical mucus in pregnant or non-pregnant women

Antibacterial activities of human cervical mucus obtained from non-pregnant and pregnant women were tested using standard blood agar plates. The combined effect of cervical mucus with cefmetazole (CMZ) was also investigated. Obtained results are summarized as follows. 1. Cervical mucus specimens obtained from 6 subjects at 9 to 36 weeks of pregnancy showed antibacterial activity to only one strain of Bacillus subtilis among organisms tested. The cervical mucus enhanced the activity of CMZ against 1 strain of Streptococcus pyogenes and 2 strains of Micrococcus luteus, but no effect was observed against other organisms tested. 2. Cervical mucus specimens obtained from non-pregnant women showed antibacterial activities to 8 of 11 strains (72.7%) of B. subtilis tested. The cervical mucus enhanced the activities of CMZ against 1 strain of S. pyogenes and 3 strains of B. subtilis. The tested organisms included Staphylococcus aureus, Escherichia coli, Bacteroides fragilis, S. pyogenes, B. subtilis, M. luteus, Streptococcus agalactiae, Enterococcus faecalis, and Candida albicans, but, as described above, cervical mucus samples showed antimicrobial activities only against B. subtilis (9/17, 52.9%), and specimens obtained only from non-pregnant women or pregnant women with less than 11 weeks of pregnancy showed any antimicrobial activities.     

Selection and identification of non-pathogenic bacteria isolated from fermented pickles with antagonistic properties against two shrimp pathogens

In this study, potential probiotic strains were isolated from fermented pickles based on antagonistic activity against two shrimp pathogens (Vibrio harveyi and Vibrio parahaemolyticus). Two strains L10 and G1 were identified by biochemical tests, followed by16S ribosomal RNA gene sequence analysis as Bacillus subtilis, and characterized by PCR amplification of repetitive bacterial DNA elements (Rep-PCR). Subsequently, B. subtilis L10 and G1 strains were tested for antibacterial activity under different physical conditions, including culture medium, salinity, pH and temperature using the agar well diffusion assay. Among the different culture media, LB broth was the most suitable medium for antibacterial production. Both strains showed the highest level of antibacterial activity against two pathogens at 30?°C and 1.0% NaCl. Under the pH conditions, strain G1 showed the greatest activity against V. harveyi at pH 7.3-8.0 and against V. parahaemolyticus at pH 6.0-8.0, whereas strain L10 showed the greatest activity against two pathogens at pH 7.3. The cell-free supernatants of both strains were treated with four different enzymes in order to characterize the antibacterial substances against V. harveyi. The result showed considerable reduction of antibacterial activity for both strains, indicating the proteinaceous nature of the antibacterial substances. A wide range of tolerance to NaCl, pH and temperature was also recorded for both strains. In addition, both strains showed no virulence effect in juvenile shrimp Litopenaeus vannamei. On the basis of these results and safety of strains to L. vannamei, they may be considered for future challenge experiments in shrimp as a very promising alternative to the use of antibiotics.