纳米银体外对三种微生物的抑制作用及机制

目的探讨纳米银广谱的抗菌作用及机制。方法以金黄色葡萄球菌、大肠埃希菌及白假丝酵母菌为研究对象,采用涂布法检测纳米银的杀菌作用,利用细菌呼吸链脱氢酶活性检测及透射电镜探讨纳米银抑菌的作用机制。结果≥0.05μg/mL的纳米银对金黄色葡萄球菌、大肠埃希菌及白假丝酵母菌具有明显的杀菌作用;5μg/mL的纳米银对金黄色葡萄球菌、大肠埃希菌及白假丝酵母菌作用60、30、15和5min均有明显的杀菌作用;纳米银对金黄色葡萄球菌、大肠埃希菌的呼吸链脱氢酶活性具有明显的抑制作用;纳米银对金黄色葡萄球菌、大肠埃希菌和白假丝酵母菌的菌体形态具有明显的破坏作用。结论纳米银对金黄色葡萄球菌、大肠埃希菌和白假丝酵母菌具有高效、迅速及广谱的杀菌作用,这些作用可能与纳米银的多靶位作用机制有关。     

黑大蒜提取物联合抗生素对金黄色葡萄球菌和肠埃希菌的体外抗菌作用研究

评价黑大蒜提取物分别与头孢唑林或庆大霉素联合应用,对金黄色葡萄球菌和大肠埃希菌的体外抗菌效应。采用液体稀释法分别测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的最低抑菌浓度（MIC）。采用棋盘法设计,微量肉汤稀释法测定黑大蒜提取物联合头孢唑林或庆大霉素对金黄色葡萄球菌和大肠埃希菌的MIC,并计算部分抑菌浓度（FIC指数）。测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的时间-杀菌曲线。黑大蒜提取物对金黄色葡萄球菌的MIC为256μg/mL,黑大蒜提取物对大肠埃希菌的MIC为256μg/mL。时间-杀菌曲线结果显示黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的抑菌作用呈现较强的浓度依赖性。黑大蒜提取物联合头孢唑林后对金黄色葡萄球菌的FIC指数为0.75;黑大蒜提取物联合庆大霉素后对大肠埃希菌的FIC指数为0.5。黑大蒜提取物与头孢唑林或庆大霉素联合用药,可明显降低抗生素对金黄色葡萄球菌和大肠埃希菌的MIC,表现为相加和协同效应。     

黑大蒜提取物联合抗生素对金黄色葡萄球菌和大肠埃希菌的体外抗菌作用研究

评价黑大蒜提取物分别与头孢唑林或庆大霉素联合应用,对金黄色葡萄球菌和大肠埃希菌的体外抗菌效应。采用液体稀释法分别测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的最低抑菌浓度(MIC)。采用棋盘法设计,微量肉汤稀释法测定黑大蒜提取物联合头孢唑林或庆大霉素对金黄色葡萄球菌和大肠埃希菌的MIC,并计算部分抑菌浓度(FIC指数)。测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的时间-杀菌曲线。黑大蒜提取物对金黄色葡萄球菌的MIC为256μg/mL,黑大蒜提取物对大肠埃希菌的MIC为256μg/mL。时间-杀菌曲线结果显示黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的抑菌作用呈现较强的浓度依赖性。黑大蒜提取物联合头孢唑林后对金黄色葡萄球菌的FIC指数为0.75;黑大蒜提取物联合庆大霉素后对大肠埃希菌的FIC指数为0.5。黑大蒜提取物与头孢唑林或庆大霉素联合用药,可明显降低抗生素对金黄色葡萄球菌和大肠埃希菌的MIC,表现为相加和协同效应。     

矾冰纳米乳对临床常见病原菌体外抗菌活性的研究

研究纳米化提高白矾与冰片复合物体外抗菌活性的效果。分别采用琼脂扩散法、体外杀菌试验及试管稀释法,测定白矾与冰片O/W型复合纳米乳对临床常见病原菌的体外抑菌、杀菌效果及最低抑菌浓度(MIC),实验中以等浓度矾冰液作为对照。结果显示,矾冰纳米乳对金黄色葡萄球菌、表皮葡萄球菌、大肠埃希菌、铜绿假单胞菌、白假丝酵母菌的抑制及杀灭活性均明显强于矾冰液(P0.05)。矾冰纳米乳对金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌临床菌株MIC90值分别为1.02、2.04和2.04 mg/mL,均明显低于矾冰液的MIC90值(P0.05)。上述实验结果提示,矾冰纳米乳与矾冰液均有广谱体外抑菌及杀菌活性,白矾及冰片复合物纳米化可提高抗菌效果。     

哈尔明盐酸盐体外抗菌活性的探讨

目的 探讨哈尔明盐酸盐（harmine）体外对常见细菌的抗菌活性,为中草药用于细菌感染的治疗提供依据。方法 用琼脂 法测定哈尔明盐酸盐的MIC值。结果 哈尔明盐酸 地临床痰液、尿液、血液、伤口分泌物等标本分离出的细菌MIC值范围如下：金黄色葡萄球菌128－256μg/ml,表皮葡萄球菌16－128μg－ml,大肠埃希氏菌100－200μg/ml,单胞菌属大于625μg/ml。结论 哈尔明盐酸盐对表皮葡萄球菌、链球菌属、大肠埃希菌抑菌作用好,对单胞菌属无抑菌作用。     

艾叶提取物的杀菌效果

采用悬液定量杀菌试验,对艾叶提取物的杀菌效果进行实验室研究。研究发现,艾叶提取物对金黄色葡萄球菌、大肠埃希菌、枯草芽胞杆菌、白假丝酵母菌和黑曲霉均具有明显的杀菌作用。通过模拟现场试验,艾叶提取物有显著的杀菌效果。     

苦参水提液的杀菌效果

采用悬液定量杀菌试验,对苦参水提液的杀菌效果进行实验室研究。研究发现,苦参水提液对金黄色葡萄球菌、大肠埃希菌、枯草芽胞杆菌、白假丝酵母菌和黑曲霉均具有明显的杀菌作用。通过模拟现场试验,苦参水提液起到了显著地杀菌效果。     

复方蛇床子灌注液对奶牛乳房炎6种主要致病菌的抑杀作用

目的通过实验证明复方蛇床子灌注液对奶牛乳房炎病原菌的抑杀作用。方法复方蛇床子灌注液为受试药物,6种引起奶牛乳房炎的常见病原菌（金黄色葡萄球菌、大肠埃希菌、无乳链球菌、停乳链球菌、白色念珠菌和热带假丝酵母菌）为实验菌株,采用测定抑菌圈的琼脂平板扩散法和测定最小抑菌浓度（M IC）的药物固体培养基法来评价复方蛇床子灌注液的体外抗菌活性。结果复方蛇床子灌注液对6种供试菌株均有较好的抑菌作用,其中0.1 g/mL的原药液对无乳链球菌和金黄色葡萄球菌表现了强大的抑制作用（M IC值达0.0015 g/mL）,抑菌圈直径分别高达33 mm和28 mm。结论复方蛇床子灌注液对奶牛乳房炎6种主要致病菌有较强的抑杀作用,抗菌谱广,药物浓度与抑菌效应呈正相关。     

醋酸氯己定的杀菌效果

采用悬液定量杀菌试验,对醋酸氯己定的杀菌效果进行实验室研究。研究发现,0.1%醋酸氯己定对金黄色葡萄球菌、大肠埃希菌、枯草芽胞杆菌、白假丝酵母菌和黑曲霉均具有明显的杀菌作用。通过模拟现场试验,醋酸氯己定起到了显著的杀菌效果。     

醋酸氯己定与乙醇的协同杀菌效果

采用悬液定量杀菌试验,对醋酸氯己定与乙醇的协同杀菌效果进行了实验室研究。研究发现,0.1%醋酸氯己定与75%乙醇混合溶液对金黄色葡萄球菌、大肠埃希菌、白假丝酵母菌和黑曲霉均呈现出显著的协同杀菌作用。结果表明,醋酸氯己定与乙醇具有良好的协同杀菌效果。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.