AgNO3对大肠杆菌和金黄色葡萄球菌的抗菌作用及机制

以大肠杆菌和金黄色葡萄球菌为模式菌,对AgNO3的抗菌效果进行研究,并对其抗菌机制作初步探讨。AgNO3对大肠杆菌的抑制生长曲线表明:2.891 mg/L的AgNO3能够完全抑制106个/mL的大肠杆菌细胞生长,AgNO3使大肠杆菌和金黄色葡萄球菌的延滞期加长,并且浓度越高,延滞期越长。另外,AgNO3对大肠杆菌和金黄色葡萄球菌脱氢酶的活性有明显影响,随着AgNO3浓度的提高,脱氢酶的活性逐渐降低。AgNO3溶液作用于细菌后,细菌表面疏水性均有不同程度地下降,且浓度越大对其影响也越明显,大肠杆菌的下降程度要大于金黄色葡萄球菌。     

微量热法研究板蓝根中四种有机酸对微生物生长代谢的影响

微量热法研究传统中药板蓝根中四种有机酸对大肠杆菌、金黄色葡萄球菌和痢疾杆菌生长代谢的影响。得到加药与不加药时大肠杆菌、金黄色葡萄球菌和痢疾杆菌生长代谢的“效-时”曲线, 以生长速率常数(k1, k2)、最大产热功率(Pm)和最大达峰时间(tm)等热力学参数来评价四种有机酸对微生物生长代谢抑制的强度和程度。四种有机酸抗微生物活性作用的顺序为: 丁香酸>邻氨基苯甲酸>水杨酸>苯甲酸, 其中苯甲酸对金黄色葡萄球菌和痢疾杆菌的生长代谢具有促进作用。本研究对板蓝根的进一步研究提供了基础和依据。     

微量热法研究板蓝根中四种有机酸对微生物生长代谢的影响

微量热法研究传统中药板蓝根中四种有机酸对大肠杆菌、金黄色葡萄球菌和痢疾杆菌生长代谢的影响。得到加药与不加药时大肠杆菌、金黄色葡萄球菌和痢疾杆菌生长代谢的“效-时”曲线, 以生长速率常数(k1, k2)、最大产热功率(Pm)和最大达峰时间(tm)等热力学参数来评价四种有机酸对微生物生长代谢抑制的强度和程度。四种有机酸抗微生物活性作用的顺序为: 丁香酸>邻氨基苯甲酸>水杨酸>苯甲酸, 其中苯甲酸对金黄色葡萄球菌和痢疾杆菌的生长代谢具有促进作用。本研究对板蓝根的进一步研究提供了基础和依据。     

乳杆菌抑制金黄色葡萄球菌对HeLa细胞的粘附

对弯曲乳杆菌Lactobacillus crispatus T79-3和T90-1、詹氏乳杆菌Lactobacillus jensenii T118-3和T231-1四株乳杆菌对金黄色葡萄球菌生长的抑制效果以及抑菌成分进行了分析,比较乳杆菌排除、竞争、置换3种不同作用方式对金黄色葡萄球菌粘附HeLa细胞的抑制作用。结果表明4株乳杆菌皆能抑制金黄色葡萄球菌的生长及其粘附HeLa细胞的能力,分析发现4株乳杆菌发挥抑制作用的主要成分是有机酸,同时比较分析乳杆菌3种不同作用方式发现它们对金黄色葡萄球菌粘附HeLa细胞的抑制效果不同,其中,排除作用方式效果最好。另外,乳杆菌对金黄色葡萄球菌粘附HeLa细胞的抑制作用具有浓度依赖性,随着乳杆菌浓度增大,抑制作用增强并逐渐达到饱和。4株乳杆菌中,T79-3粘附能力最强,对金黄色葡萄球菌的抑制作用最强,排除作用方式抑制金黄色葡萄球菌粘附HeLa细胞作用效果较好,提示乳杆菌T79-3有可能作为益生菌防治妇女泌尿生殖道感染。     

11种食药同源植物提取物对果蔬常见腐败菌的抑菌活性研究

本文以花椒、高良姜等11种食药同源植物提取物为供试材料,分别研究了其对扩展青霉、灰葡萄孢、链格孢和大肠杆菌、金黄色葡萄球菌等5种常见果蔬腐败菌的抑制作用。结果表明,花椒对三种霉菌抑制作用最强,高良姜和莱菔子对扩展青霉和链格孢有一定抑制作用。花椒对三种霉菌的最小抑菌浓度分别为25. 00、25. 00、50. 00 mg/m L,最小杀菌浓度分别为50. 00、100. 00、100. 00 mg/m L。花椒对三种霉菌的孢子萌发有显著抑制作用。花椒提取液处理樱桃番茄可显著降低果实发病率,延长果实保鲜期。11种食药同源植物提取液对大肠杆菌抑菌效果较差。高良姜和天麻对金黄色葡萄球菌抑菌效果突出,可显著抑制金黄色葡萄球菌生长,二者对金黄色葡萄球菌的MIC分别为7. 50和30. 00 mg/m L,MBC分别为15. 00和60. 00 mg/m L。     

薇甘菊水提物的抑菌试验研究

以枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌为代表,分别探讨了薇甘菊水溶性提取物对上述3种细菌在培养24 h过程中的光密度、活菌数和最低杀菌浓度的影响。试验结果表明,在一定浓度范围内薇甘菊水提物对上述3种细菌均有不同程度的抑制作用。其中,枯草芽孢杆菌的抑制作用最强,其次是大肠杆菌和金黄色葡萄球菌。透射电镜观察结果表明,薇甘菊水提物可抑制金黄色葡萄球菌细胞壁的分离,因而抑制了细胞的分裂而达到抑菌效果。     

中药鹿藿的抑菌实验研究

研究发现中药鹿藿在体外可瞬间抑制人类精子的运动。为了研究中药鹿藿的抑菌作用,本实验对几种女性生殖道常见致病菌和条件致病菌进行了体外抑菌实验,发现鹿藿对金黄色葡萄球菌、淋病奈瑟氏菌和大肠杆菌有抑制作用,并可抑制常见耐药菌株的生长。金黄色葡萄球菌的MIC折合生药为31.25mg/mL,大肠杆菌的MIC250mg/mL,淋球菌的MIC为31.25mg/mL。结果表明中药鹿藿在能有效抑制精子运动的浓度可以抑制某些男、女性生殖道常见细菌的生长。     

低聚壳聚糖美拉德衍生物抑菌性能研究

本文研究了基于与葡萄糖、麦芽糖和木糖进行美拉德反应的低聚壳聚糖衍生物的抑菌性.测定低聚壳聚糖及其衍生物对大肠杆菌和金黄色葡萄球菌的抑制效果.结果显示:壳聚糖及其衍生物对金黄色葡萄球菌的抑制作用强于对大肠杆菌的抑制作用,且随着浓度增加,对两种菌的抑菌效果增强.大多数壳聚糖衍生物的抑菌效果优于壳聚糖本身,其中CG 1∶1 8 h(低聚壳聚糖的氨基与葡萄糖的羰基的物质量比为1∶1,反应8h)的抑菌效果最好,CM 1∶3 8 h(低聚壳聚糖的氨基与麦芽糖的羰基的物质量比为1∶3,反应8 h)抑菌性最差,这可能与参加反应的还原糖种类、反应物比例以及反应时间相关.     

紫甘薯花色苷色素的抑菌作用研究

本文研究了紫甘薯花色苷色素抑制大肠杆菌、金黄色葡萄球菌、啤酒酵母和黑曲霉的作用及机理。结果表明：紫甘薯花色苷色素对大肠杆菌及金黄色葡萄球菌均有抑制作用, 并与其浓度呈正相关, 而对啤酒酵母和黑曲霉无抑制作用。透射电镜观察和大肠杆菌生长曲线表明, 该色素的抑菌作用可能是通过增强细胞膜的通透性, 使细胞异常生长, 抑制对数生长期的细胞分裂, 使细胞质稀薄、细胞解体。SDS-PAGE 分析表明, 紫甘薯花色苷对大肠杆菌蛋白表达影响不明显, 未见特征性条带的消失, 仅对部分蛋白质合成量有影响。     

紫甘薯花色苷色素的抑菌作用研究

本文研究了紫甘薯花色苷色素抑制大肠杆菌、金黄色葡萄球菌、啤酒酵母和黑曲霉的作用及机理.结果表明:紫甘薯花色苷色素对大肠杆菌及金黄色葡萄球菌均有抑制作用,并与其浓度呈正相关,而对啤酒酵母和黑曲霉无抑制作用.透射电镜观察和大肠杆菌生长曲线表明,该色素的抑菌作用可能是通过增强细胞膜的通透性,使细胞异常生长,抑制对数生长期的细胞分裂,使细胞质稀薄、细胞解体.SDS-PAGE分析表明,紫甘薯花色苷对大肠杆菌蛋白表达影响不明显,未见特征性条带的消失,仅对部分蛋白质合成量有影响.     

The effect of parabens on DNA, RNA and protein synthesis in Escherichia coli and Bacillus subtilis

The effect of methyl, propyl and butyl esters of p-hydroxybenzoic acid on DNA and RNA synthesis has been tested in toluenized cells of Escherichia coli and Bacillus subtilis. Both RNA and DNA synthesis of these bacteria were inhibited. The inhibitory concentrations were higher than those previously reported for growth inhibition. Protein synthesis in cell-free extracts (S-30 fraction) of B. subtilis was even more sensitive to parabens than DNA and RNA synthesis, while protein synthesis in Esch. coli was largely unaffected.     

The effect of parabens on DNA, RNA and protein synthesis in Escherichia coli and Bacillus subtilis

The effect of methyl, propyl and butyl esters of p -hydroxybenzoic acid on DNA and RNA synthesis has been tested in toluenized cells of Escherichia coli and Bacillus subtilis. Both RNA and DNA synthesis of these bacteria were inhibited. The inhibitory concentrations were higher than those previously reported for growth inhibition. Protein synthesis in cell-free extracts (S-30 fraction) of B. subtilis was even more sensitive to parabens than DNA and RNA synthesis, while protein synthesis in Esch. coli was largely unaffected.     

Absence in Bacillus subtilis and Staphylococcus aureus of the sequence-specific deoxyribonucleic acid methylation that is conferred in Escherichia coli K-12 by the dam and dcm enzymes

Restriction analysis of plasmid pHV14 deoxyribonucleic acid isolated from Escherichia coli K-12, Bacillus subtilis, and staphylococcus aureus with restriction endonucleases MboI, Sau3AI, and EcoRII was used to study the methylation of those nucleotide sequences which in E. coli contain the major portions of N6-methyladenine and 5-methylcytosine. The results showed that neither B. subtilis nor S. aureus methylates deoxyribonucleic acid at the same sites and nucleotides which are recognized and methylated by dam and dcm enzymes in E. coli K-12.     

西瓜藤提取物的抑菌作用研究

采用琼脂稀释法研究西瓜藤提取物的体外抑菌作用,用小鼠腹腔注射金黄色葡萄球菌法研究80%醇提物的体内抑菌作用。结果表明:西瓜藤提取物对金黄色葡萄球菌、大肠埃希氏菌、铜绿假单胞菌、伤寒沙门氏菌、枯草芽孢杆菌和肺炎克雷伯氏菌均有不同程度的抑制作用,但对链球菌作用不明显。其中80%醇提取物和乙酸乙酯萃取物抑制金黄色葡萄球菌活性最好,其最低抑菌浓度(MIC)分别为4.2、8.4mg.mL-1。体内实验也表明,乙醇提取物具有较好的抑菌作用。西瓜藤提取物具有抑菌活性,在抑菌方面有一定开发前景。     

马缨丹抑菌试验研究

目的：研究马缨丹的体外抑菌效果。方法：制备马缨丹水煎煮液和乙醇提取液,测定其对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌圈直径、最小抑菌浓度及灭菌前后提取液抑菌效果的变化。结果：当两种提取液生药含量大于0.4 g/mL时,它们对三种细菌的抑菌效果依次为：枯草芽孢杆菌〉金黄色葡萄球菌〉大肠杆菌。马缨丹乙醇提取液对三种细菌的最小抑菌浓度分别为1/64g/mL1、/16g/mL和1/32g/mL,都比水煎煮液的结果1/32g/mL、1/8g/mL和1/16g/mL低。两种提取液经121℃高压蒸汽灭菌处理后对枯草芽孢杆菌和金黄色葡萄球菌的抑制作用有所增强。结论：两种提取液对三种细菌均有不同程度的抑制作用,因此,马缨丹可考虑用于食品、化妆品及饲料防腐等领域,以提高产品质量。     

Biosynthesis of Bacillus licheniformis penicillinase in Escherichia coli and in Bacillus subtilis.

Modified prepenicillinase was accumulated in both Escherichia coli and Bacillus subtilis treated with globomycin. Although the inhibitions of processings of prepenicillinase and prolipoprotein by globomycin in E. coli are qualitatively similar, they differ in the degree of inhibition at given concentrations of globomycin. The processing of prepenicillinase proceeds much more rapidly in E. coli than in B. subtilis.     

Antimicrobial and antiviral screening of novel indole carboxamide and propanamide derivatives

A few series of indole derivatives were screened for antimicrobial, antifungal and anti-HBV activities. The compounds were tested for their in vitro antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and for their antifungal activity against Candida albicans using a disc diffusion method, which measures the diameter of the inhibition zone around a paper disc soaked in a solution of the test compounds. The antimicrobial activity results showed that all compounds are as a active as the standard compound ampicillin against Staphylococcus aureus. It was also found that indole carboxamide derivatives, substituted at 3-position with several benzyl groups, showed better inhibition of Bacillus subtilis than their congeners substituted at 2-position. Activity patterns of the compounds against Escherichia coli and Staphylococcus aureus were found slightly different by the same method. In this case, there was no correlation between structure and activity of the compounds. The antifungal activity of carboxamide derivatives was found higher compared to that of the propanamide derivatives. The minimum inhibitory concentration (MIC) values of some indole derivatives were also determined by the tube dilution technique. The MIC values of the compounds were found nearly 20- to 100-fold smaller compared to the standard compounds ciprofloxacin and ampicillin (1.56-3.13 microg/ml and 1.56-12.5 microg/ml, respectively) against Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The MIC values of the tested compounds showed that these are better inhibitors for Candida albicans. Indole derivatives were screened by the anti-HBV susceptibility test. No compound showed good inhibition against the HBV virus.     

Analysis of an mRNA exhibiting anomalous translational specificity.

Gene 6 mRNA of Bacillus subtilis phage phi 29 is inefficiently translated under standard in vitro conditions by Escherichia coli, while it is efficiently translated by the in vitro system derived from B. subtilis. This is a rare example of the inability of E. coli to translate mRNA translated by B. subtilis. The ionic condition in the translation systems was the key component in the differential recognition of the gene 6 message by E. coli and B. subtilis ribosomes. Its translation by E. coli ribosomes was preferentially inhibited by moderate levels of KCl, while its translation by B. subtilis ribosomes was unaffected by these concentrations of salt. This preferential inhibition with E. coli ribosomes was observed in vitro as well as in vivo. While not influencing the general phenomenon of preferential inhibition, anion-specific effects were observed in overall protein synthesis. Glutamate and acetate promoted efficient synthesis over a broad range of concentrations, whereas chloride was inhibitory at all concentrations tested.     

Functional specificity of the replication fork-arrest complexes of Bacillus subtilis and Escherichia coli: significant specificity for Tus-Ter functioning in E. coli

The Escherichia coli replication terminator TerB was inserted in its two alternate orientations into a Bacillus subtilis fork-arrest assay plasmid. After transferring these new plasmids into B. subtilis, which could overproduce the E. coli terminator protein Tus, it was shown that the E. coli Tus-TerB complex could cause polar replication fork arrest, albeit at a very low level, in B. subtilis. A new B. subtilis-E. coli shuttle plasmid was designed to allow the insertion of either the Terl (B. subtilis) or TerB (E. coli) terminator at the same site and in the active orientation in relation to the approaching replication fork generated in either organism. Fork-arrest assays for both terminator-containing plasmids replicating in both organisms which also produced saturating levels of either the B. subtilis terminator protein (RTP) or Tus were performed. The efficiency of the Tus-TerB complex in causing fork arrest was much higher in E. coli than in B. subtilis. The efficiency of the B. subtilis RTP-Terl complex was higher in B. subtilis than in E. coli, but the effect was significantly less. Evidently a specificity feature in E. coli operates to enhance appreciably the fork-arrest efficiency of a Tus-Ter complex. The specificity effect is of less significance for an RTP-Ter complex functioning in B. subtilis.     

壳聚糖复合物的抑菌性研究

自制了壳聚糖系列复合物(CTS-X):黄原酸化壳聚糖(CTS-CS2)、巯基化壳聚糖(CTS-SH)、壳寡聚糖(O-CTS)、不同溶剂化的壳聚糖(CTS)及这些物质的系列金属离子(Ca、Zn、Fe、Mn、Cu、Ni、Co、Ag)配合物。分别用圆滤纸法和杯碟法对细菌和真菌:金黄葡萄球菌、枯草杆菌、大肠杆菌及黑曲霉和冻土毛霉等,进行了抑菌性研究。并讨论了最低抑菌浓度,作了抑菌曲线。经系统筛选得到对枯草杆菌有特效抑菌性的黄原酸化壳聚糖锌(CTS-CS2-Zn),对金黄葡萄球菌有特效抑菌性的黄原酸化壳聚糖银(CTS-CS2-Ag)。并用具有一定抑菌性和一定还原性的CTS-X作为水果保鲜剂对草莓、荔枝、樱桃等作了保鲜研究,收到良好效果。为CTS-X的广泛应用提供了实验依据。