一株铜绿假单胞菌的溶磷特征及其对底泥中Pb的固定化

通过纯培养和模拟实验研究一株铜绿假单胞菌JM1对磷酸钙的溶解特征及其对底泥中Pb的固定化作用. 结果表明: 菌株JM1对磷酸钙和磷酸铝均具有溶解作用, 96 h内释放的溶解性正磷酸盐的质量浓度分别为240.63,92.73 mg/L, 培养液pH值分别下降至464,512, 菌株JM1还可以利用卵磷脂进行生长但不释放磷酸根离子; 菌株JM1使灭菌底泥与不灭菌底泥中固定化Pb的质量比分别增加至14.02,11.83 mg/kg, 即菌株JM1对底泥中的Pb具有较强的固定能力.     

北京地区动物实验设施动物饮水无菌检测 及绿脓杆菌污染菌株鉴定

摘要: 目的了解北京地区动物实验设施动物饮水微生物控制状况。方法根据实验动物无菌动物生活环境国家 标准检测方法,对实验动物设施内的动物饮用水样品进行分离培养。扩增分离绿脓杆菌的16SrRNA,并进行测序, 绘制发育树。结果在27 个参与检测的单位中,未经过处理的饮水无菌生长率41% ; 经过处理的饮水无菌生长率 仅29% 。绿脓杆菌检出率30% ,主要为RHH13 和ZAQ22 两个菌株。结论本次检测的实验动物饮水在处理后的 效果普遍不甚理想,存在绿脓杆菌的污染,直接影响实验动物质量。     

生物表面活性剂鼠李糖脂的纯化与表征

生物表面活性剂鼠李糖脂是微生物在一定条件下产生的次级代谢产物,其分子具有极性亲水基团和非极性亲油基团结构,通常表现出很高的表面活性和界面优先分配能力。可靠的分离提纯方法和成分鉴定手段是鼠李糖脂生产工艺成功的重要保证。实验通过好氧发酵培养铜绿假单胞菌CCTCC AB93066、酸沉降分离得到鼠李糖脂后,利用柱色谱提纯技术得到纯化的鼠李糖脂的单糖脂和二糖脂,最后采用高效液相色谱-质谱联用法进行成分鉴定。结果显示这两种鼠李糖脂均含有3种主要成分,其中单糖脂的主要成分为RhaC₁₀C₁₀、RhaC₁₀C₁₂-H₂、RhaC₁₀C₁₂,二糖脂的主要成分为Rha₂C₁₀C₁₀、Rha₂C₁₀C₁₂-H₂、Rha₂C₁₀C₁₂。该研究结果表明,铜绿假单胞菌CCTCC AB93066是一种良好的鼠李糖脂产生菌;酸沉降-柱色谱技术可以用于鼠李糖脂的深度提纯,且有较好的效果;而高效液相色谱-质谱联用技术对鼠李糖脂成分鉴定具有灵敏度高和准确性好等优点,是一种较为可靠的检测方法。     

Purification and Partial Characterization of a Collagenolytic Enzyme Produced by Pseudomonas aeraginosa SCU Screened from Rotten Hides

Strain Pseudomonas Aeraginosa SCU isolated from rotten hides is shown to produce various gelatinolytic enzymes with molecular masses ranging from - 50 to - 200 kD. A gelatinolytic enzyme called PAC exhibiting collagenolytic activity is purified by SP sepharose fast flow, Sephadex G-200 gel filtration and native PAGE cutting method. The purified enzyme has an apparent molecular weight of about 110 kD by SDS PAGE without β-mercaptoethanol. Treatment withtβ-Me suggests that PAC is dissociated into three subunits approximately 33 kD, 25 kD and 20 kD with a ratio of 2:1:1, named sub A, sub B and sub C repectively. EDFA and EGTA display a significant inhibitory effect on the enzyme activity while PMSF, leupeptin and pepstain do not appreciably inhibit it. The first 15 amino acid residues of the major subunit (subA) are determined and the sequence is Ala-Glu-Ala-Gly-Gly-Pro-Gly-Gly-Asn-Gln-Lys-Ile-Gly -Lys-Tyr. This sequence is identical to that of elastase of P. aeruginosa. The fragment of encoding mature sub A is cloned and its sequence is determined, which has a high homology with the gene of elastase. These results indicate that PAC is a novel collagenolytic metalloprotease composed of three kinds of subunits, of which elastase is the major one.     

Effect of the Distillation Time on the Chemical Composition,Antioxidant Potential and Antimicrobial Activity of Essential Oils from Different Cannabis sativa L. Cultivars

Within the unavoidable variability of various origins in the characteristics of essential oils, the aim of this study was to evaluate the effect of the distillation time on the chemical composition and biological activity of Cannabis sativa essential oils (EOs). The dry inflorescences came from Carmagnola, Kompolti, Futura 75, Gran Sasso Kush and Carmagnola Lemon varieties from Abruzzo region (Central Italy), the last two being new cultivar here described for the first time. EOs were collected at 2 h and 4 h of distillation; GC/MS technique was applied to characterize their volatile fraction. The EOs were evaluated for total polyphenol content (TPC), antioxidant capacity (AOC) and antimicrobial activity against food-borne pathogens and spoilage bacteria. The time of distillation particularly influenced EOs chemical composition, extracting more or less terpenic components, but generally enriching with minor sesquiterpenes and cannabidiol. A logical response in ratio of time was observed for antioxidant potential, being the essential oils at 4 h of distillation more active than those distilled for 2 h, and particularly Futura 75. Conversely, except for Futura 75, the effect of time on the antimicrobial activity was variable and requires further investigations; nevertheless, the inhibitory activity of all EOs against Pseudomonas fluorescens P34 was an interesting result.     

50味中药与8种抗生素对变形假单胞菌的体外抑菌作用

用牛津杯法选择诃子、大黄、黄连等50种单方中药对变形假单胞菌、金黄色葡萄球菌进行体外抑菌试验,并选用抑菌作用较好的药物组成复方二联、三联中药,药物质量浓度为60,240 mg/mL。结果表明:单方中药中,诃子对变形假单胞菌抑菌作用明显,为极敏感;复方二联中药中,240 mg/mL的诃子+白芍等4种对变形假单胞菌的抑菌作用明显,为极敏感;复方三联中药中,60 mg/mL的黄连+板蓝根+黄柏等5种对变形假单胞菌的抑菌效果为极敏感,240 mg/mL的黄连+连翘+黄芪等6种对变形假单胞菌的抑菌作用为极敏感;变形假单胞菌对恩诺沙星、盐酸多西环素、硫酸新霉素及硫酸庆大霉素4种药物高度敏感。由此认为黄连+板蓝根+黄柏等11个复方三联中药与恩诺沙星对变形假单胞菌抑菌作用最强,同时筛选出多个抑菌作用效果良好的复方三联中药和抗生素,可用于鱼病防治研究。     

Degradation of dibutyltin in sea water by pyoverdins isolated from Pseudomonas chlororaphis

The yellow compounds pyoverdins were isolated from Pseudomonas chlororaphis, which was isolated from mud in Japan. Degradation of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) by pyoverdin (20 mg) was carried in sea water (30 ml) containing a 6 µg l^?1 concentration of TBT, DBT, and MBT at 24 °C for 24 h in aerobic conditions. TBT, DBT, and MBT in sea water were analyzed by gas chromatography–mass spectrometry in selected ion monitoring mode. DBT in sea water was degraded to MBT by pyoverdins isolated from P. chlororaphis. However, TBT and MBT in sea water was not degraded by pyoverdins. The optimum degradation of DBT in sea water was at pH 4.8–8.2, at a temperature 25–30 °C. Copyright © 2002 John Wiley & Sons, Ltd.     

大亚湾海洋细菌Pseudomonas sp.中的红色素

海洋细菌Pseudomonas sp.，采集于大亚湾，从该菌的菌体提取物分离得到2个红色素：灵菌红素A和新的衍生物二甲基灵菌红素B。它们的结构通过NMR，LC-MS等确定，并得出灵菌红素是具有强烈抗微生物和细胞毒性的化合物，同时研究了它的培养条件。