鲑点石斑鱼和大眼鳜鳃的扫描电镜观察

对鲈形目科、底栖生活、凶猛肉食性的鲑点石斑鱼 (Epinephelusfario)和大眼鳜 (Sinipercakneri)鳃的结构进行扫描电镜观察。结果表明 ,两种鱼鳃的表面结构和微细结构与其他硬骨鱼类基本相似 ,鳃丝表面都具有规则或不规则分布的环形微嵴、沟、坑、孔等结构 ;然而两者的鳃小片都较高 ,表面更加凹凸不平 ,是对低溶氧环境的适应。鲑点石斑鱼的鳃丝表面一部分较为平坦 ,另一部分则凹凸不平 ,其鳃小片高度也高于大眼鳜 ,因而具有更大的表面积和较高的摄氧效率。在扫描电镜下能在鲑点石斑鱼和大眼鳜的鳃上分辨出扁平上皮细胞、氯细胞和粘液细胞 3种细胞 :前者鳃上的扁平上皮细胞界限清楚 ,而后者的界限模糊且表面遍布不规则的微嵴 ;前者的鳃丝和鳃小片上氯细胞的数量明显多于后者 ,两者细胞形态也存在差异 ;而鳃丝表面的粘液细胞的数量则是后者较多。两种鱼鳃上的细胞的形态结构及数量分布存在的差异 ,可能与前者生活于海水而后者生活于淡水的不同生活环境有关。     

银杏种仁中抗菌蛋白的纯化及性质

银杏果仁提取上清液经硫酸铵沉淀、CM—52离子交换柱层析和Sephadex G-50凝胶过滤层析后分离纯化出一种抗菌蛋白。SDS—PAGE分析结果表明,此蛋白分子量为13000,对热稳定;氨基酸组分分析表明,该蛋白含18种不同氨基酸,尤富含丙氨酸(Ala)和精氨酸(His)等,缺乏半胱氨酸(Cys);纯化的蛋白对黄瓜镰刀孢菌(Fusarium oxysporum)、瓜类炭疽菌(Colletotrichum orbiculare)、小麦全蚀病菌(Gaeumannomyces graminis)等真菌有很强的抑制作用,而且对金黄色葡萄球菌(Staphylococcus aureus)、大肠杆菌(Escherichia Coli)等细菌也有一定的抑制作用。     

红茶菌抗菌蛋白提取与纯化

红茶菌液经过滤、离心、减压浓缩 ,丙酮加盐沉淀 ,Sephadex G-50柱层析后 ,得到两个分子量部分 ,其中小分子量部分有抗菌活性 ,采用尿素— SDS—PAGE测定抗菌蛋白分子量未获成功     

斜带石斑鱼MyD88基因的原核表达及蛋白纯化

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海水小球藻抗菌蛋白的分离纯化及性质研究

海水小球藻(Chlorella pacifica)提取液经硫酸铵沉淀、DEAE-52离子交换层析和SephadexG-200凝胶过滤层析后分离纯化出1种抗菌蛋白.经SDS-PAGE测定,两个亚基的相对分子量分别为61 kD和70 kD;该抗菌蛋白对热稳定,氨基酸组成分析表明含17种氨基酸,其中谷氨酸的含量最高,其次为甘氨酸与天冬氨酸,胱氨酸的含量最低.在抗菌活性中,纯化的蛋白质对产黄青霉(Penicillium chrysogenum)和中华根霉(Rhizopus chinensis)有较强的抑制作用,对金黄色葡萄球菌(staphy lococcus aureus)和肠炎病病原菌(Ameromonas punctata)也有抑制作用,其抗真菌活性比抗细菌强.     

家蝇幼虫抗菌相关蛋白/多肽的诱导及抗菌活性分析

对家蝇Musca domestica 3龄幼虫进行针刺、带菌针刺、热激和超声4种处理,并于处理后不同时间分别收集提取家蝇幼虫体内耐热总蛋白,比浊法测定其抗菌活性,经逐步回归分析确定抗菌相关蛋白/多肽。结果表明,4种处理均能诱导家蝇幼虫产生抗菌物质,其中表观分子量为22 kD的蛋白对藤黄微球菌和大肠杆菌均有抗菌作用,50 kD,13 kD,26 kD,7 kD的蛋白抗菌活性具有专一性。还发现一种37 kD的蛋白对抗菌活性有负作用,推测它可能是促进细胞生长的物质。     

类芽孢杆菌(Paenibacillus sp.)蛋白质组学研究中三种蛋白提取方法的比较分析

【目的】革兰氏阳性类芽孢杆菌（Paenibacillus sp.）本身细胞壁的结构特点导致其菌体全蛋白不易获得。本研究选取了3种破碎方法——溶菌酶联合超声破碎法（方法一）、溶菌酶联合SDS热处理破碎法（方法二）、液氮联合超声破碎法（方法三）进行革兰氏阳性菌的细胞破碎,以期获得适于样品菌株基于质谱技术进行蛋白质组学研究的制备方法。【方法】在蛋白样品的制备过程中,对3种不同破碎方法的蛋白提取得率和SDS-PAGE检测分析结果进行比较;随后将3种蛋白样品制备方法的样品用质谱技术进行鉴定,分析不同蛋白样品基于质谱技术鉴定蛋白的差异。【结果】在蛋白样品的制备提取过程中,不同破碎方法的蛋白提取率大致相同。用单因素方差比较3种提取方法质谱鉴定蛋白数的差异性,方法三鉴定的蛋白数最多（2 638个）,其次是方法一（2 452个）,方法二鉴定的蛋白数最少（2 003个）。进一步用韦恩图分析比较不同提取方法的蛋白鉴定通量差异,综合考虑蛋白提取效率的结果以及液氮研磨法提取蛋白的缺点,最终选取溶菌酶联合超声破碎法（方法一）提取菌株全蛋白作为该菌基于质谱分析其蛋白质组学研究中最适合的方法。最后,对质谱鉴定菌株蛋白包括分子量、等电点、疏水性的基本性质进行分析,发现3种破碎方法质谱鉴定的蛋白与模式菌株多黏类芽孢杆菌（Paenibacillus polymyxa）基因组中预测蛋白的各个组分分布占比基本一致,都保证了菌株蛋白质组数据信息的完整性。【结论】基于质谱技术开展革兰氏阳性类芽孢杆菌（Paenibacillus sp.）的蛋白质组学研究,溶菌酶联合超声破碎法是提取该菌株全蛋白最适合的方法。     

内芽孢杆菌属细菌(Paenibacillus daejeonensis)SS02抗菌蛋白的分离纯化和其性质的研究

内芽孢杆菌属细菌（Paenibacillus daejeoneusis）SS02,是一株能强烈抑制玉米纹枯菌（Rhizoctonia cerealis）、白色念珠菌（Candidal vaginitis）等病害真菌的拮抗菌株。SS02菌株培养液经硫酸铵分级盐析,SephadexG-75凝胶柱层析和DEAE-32纤维素柱层析分离纯化出一种抗菌蛋白,命名为SD22。蛋白电泳分析结果表明,此蛋白分子量为56000,等电点为6．4。此蛋白对热和紫外线稳定,对蛋白酶部分敏感。纯化后的SD22对玉米纹枯菌（Rhizoctonia cerealis）、油菜菌核病（Sclerotinia sclerotiorum）、苹果轮纹病菌（Physalospora piricala）、绿色木霉（Triclwdema viride）、绿色粘帚霉（Gliocladium viride）、弯孢霉菌（Curvula rialeafspot）、镰刀霉菌（Fusarium sp．）、赤霉菌（Fusarium headblight）、球孢白僵菌（Beauveria bassiana）、大肠杆菌（Escherichia coli）、金黄色葡萄球菌（Staphylo-coccus aureus）、枯草芽孢杆菌（Bacillus subtilis）、白色念珠菌（Candidal vaginitis）、冬瓜枯萎菌（Fusarium oxysporum Schl．emend,Snyder＆Hause）等菌有很强的抑制作用。     

内芽孢杆菌属细菌（Paenibacillus daejeonensis）SS02抗菌蛋白的分离纯化和其性质的研究

内芽孢杆菌属细菌（Paenibacillus daejeonensis）SS02,是一株能强烈抑制玉米纹枯菌（Rhizoctonia cerealis）、白色念珠菌 (Candidal vaginitis)等病害真菌的拮抗菌株。SS02菌株培养液经硫酸铵分级盐析,Sephadex G-75凝胶柱层析和DEAE-32纤维素柱层析分离纯化出一种抗菌蛋白,命名为SD22。蛋白电泳分析结果表明,此蛋白分子量为56000,等电点为6.4。此蛋白对热和紫外线稳定,对蛋白酶部分敏感。纯化后的SD22对玉米纹枯菌(Rhizoctonia cerealis)、油菜菌核病(Sclerotinia sclerotiorum)、苹果轮纹病菌（Physalospora piricala）、绿色木霉(Trichodema viride)、绿色粘帚霉（Gliocladium viride）、弯孢霉菌(Curvularia leaf spot)、镰刀霉菌(Fusarium sp.)、赤霉菌(Fusarium head blight)、球孢白僵菌（Beauveria bassiana）、大肠杆菌（Escherichia coli）、金黄色葡萄球菌（Staphylo-coccus aureus）、枯草芽孢杆菌（Bacillus subtilis）、白色念珠菌(Candidal vaginitis）、冬瓜枯萎菌（Fusarium oxysporum Schl.emend.Snyder & Hanse）等菌有很强的抑制作用。     

上海某三甲医院2014—2021年血流感染病原菌的分布及耐药性分析

本研究旨在分析血流感染病原菌种类分布及其耐药率,为临床合理使用抗菌药物提供参考。对2014—2021年同济大学附属东方医院血培养标本分离的主要病原菌及其耐药性进行统计分析,结果显示剔除重复菌株后,本院8年血培养标本共检出病原菌1 396株,以革兰氏阴性杆菌为主,占56.3%,其次为革兰氏阳性球菌(38.4%)和真菌(5.3%)。居前8位的菌株为大肠埃希菌(21.5%)、凝固酶阴性葡萄球菌(coagulase negative Staphylococcus, CNS) (17.4%),肺炎克雷伯菌(14.9%)、金黄色葡萄球菌(7.2%),鲍曼不动杆菌(5.4%),粪肠球菌(4.2%),屎肠球菌(3.7%)和铜绿假单胞菌(3.5%)。大肠埃希菌对第3代头孢菌素的耐药率超过50%,对碳青霉烯类药物的耐药率低至1%;肺炎克雷伯菌对碳青霉烯类药物的耐药率高达46.3%;鲍曼不动杆菌对头孢类、氨基糖苷类和碳青霉烯类的累计耐药率均大于45%。耐甲氧西林金黄色葡萄球菌和耐甲氧西林凝固酶阴性葡萄球菌(methicillin-resistant coagulase-negative Staphylococci, MRCNS)分别为44.6%和74.5%的占比。     

重庆地区儿童2000年至2004年首位革兰阴性细菌和阳性细菌的耐药性监测

目的了解重庆地区儿童感染的分离至临床标本的首位革兰阴性细菌和阳性细菌对常用抗生素的耐药趋势,指导临床合理使用抗生素。方法常规方法分离、培养细菌,应用美国德灵公司WalkAway-40细菌鉴定仪对2000年至2004年我院细菌室分离至临床标本的首位革兰阴性细菌和阳性细菌共2854株进行细菌鉴定及药敏试验。结果2000年至2004年检出的首位革兰阴性细菌和阳性细菌分别为大肠埃希菌和金黄色葡萄球菌。2000年至2004年前5位革兰阴性菌5777株,革兰阳性菌1565株,其中大肠埃希菌2090株,金黄色葡萄球菌764株,分别占36.2%和48.8%;5年间大肠埃希菌对氨苄西林、头孢吡肟、头孢西丁、庆大霉素、亚胺培南、环丙沙星、头孢噻肟、头孢他啶的总耐药率分别为80.9%、37.5%、15.4%、54.0%、0.8%、34.0%、46.6%、46.2%;金黄色葡萄球菌对青霉素、红霉素、复方新诺明、万古霉素、阿莫西林/克拉维酸的总耐药率分别为95.6%、63.4%、5.8%、0%、11.0%。结论通过细菌耐药监测发现：大肠埃希菌对常用抗生素的总耐药率变化不大,金黄色葡萄球菌对常用抗生素的总耐药率有下降趋势,应引起临床医生重视。     

Gut immune stimulation by non pathogenic Gram(+) and Gram(-) bacteria. Comparison with a probiotic strain

We analyzed the gut immune stimulation induced by Gram-positive bacteria: non probiotic Lactobacillus acidophilus CRL 1462 and Lactobacillus acidophilus A9; two potentially probiotic strains: L. acidophilus CRL 924 and Lactobacillus delbrueckii subsp. bulgaricus CRL 423; comparatively with a probiotic strain: Lactobacillus casei CRL 431. We also studied Gram-negative bacteria: Escherichia coli 129 and E. coli 13-7 in BALB/c mice. All the strains increased the number of IgA+ cells. We analyzed the cytokines IFNγ, TNFα, IL-17, IL-12, IL-6 and MIP-1α. The Gram(+) strains increased the number of IL-10+ cells. Gram(−) strains did not increase IL-10+ cells, but they increased the number of IL-12+ cells. The probiotic strain increased mainly IFNγ and TNFα. In the study of the receptors TLR-2, TLR-4 and CD-206, we demonstrated that only the probiotic strain increased the number of CD-206+ cells. All the Gram(+) strains increased the number of TLR-2+ cells and the Gram(−) strains of the TLR-4+ cells. The probiotic strain induced the release of IL-6 by a preparation enriched in intestinal epithelial cells (IEC). Gram(+) and Gram(−) bacteria activated different immune receptors and induced a different cytokine profile. The probiotic strain showed a great activity on the immune cells and the enriched population in IEC, activating mainly cells of the innate immune system.     

Synthesis and biological evaluation of α-hydroxyalkylphosphonates as new antimicrobial agents

A set of α-quaternary 3-chloro-1-hydroxyalkylphosphonates, analogues of fosfomycin and fosfonochlorin, some of which are new compounds, was synthesized. The compounds were screened for bioactivity against several clinical and standard microbial isolates. Some were found to have moderate activity. The activity was higher with phenyl protection of the phosphoryl ester groups and α-phenyl substitution. Compound 11 was as effective or more potent than fosfomycin or chloramphenicol against several Gram-negative bacteria as well as against some Gram-positive ones.     

Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn

The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria. The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus, coagulase-negative stahylococci, S. pyogenes, S. agalactiae, S. aureus ATCC 29213, E. faecalis ATCC 29212) and Gram-negative bacteria (E. coli., K. pneumoniae, P. mirabilis, E. cloacae, S. marcescens, M morganii, A. baumannii, P. aeruginosa, S. maltophilia, E. coli ATCC 35218, P. aeruginosa ATCC 27853, E. coli ATCC 25922). All ethanolic extracts showed activity against gram-positive bacteria. Among all obtained extracts, only leaf and flower fluid extracts showed activity against Gram-negative bacteria. Based on this bioassay, leaf fluid extracts tended to be the most potent, followed by flower fluid extracts. Minimal inhibitory concentration (MIC) values of extracts and antibiotics were comparatively determined by agar and broth dilution methods. Both extracts were active against S. aureus, coagulase-negative stahylococci, E. faecalis and E. faecium and all tested Gram-negative bacteria with MIC values from 0.067 to 0.308 mg/ml. In this study the minimal bactericidal concentration (MBC) values were identical or twice as high than the corresponding MIC for leaf extracts and four or eight times higher than MIC values for flower extracts. This may indicate a bactericidal effect. Stored extracts have similar antibacterial activity as recently obtained extracts. The A. aroma extracts of leaves and flowers may be useful as antibacterial agents against Gram- negative and Gram-positive antibiotic multi-resistant microorganisms.     

SecretP: Identifying bacterial secreted proteins by fusing new features into Chou’s pseudo-amino acid composition

Protein secretion plays an important role in bacterial lifestyles. Secreted proteins are crucial for bacterial pathogenesis by making bacteria interact with their environments, particularly delivering pathogenic and symbiotic bacteria into their eukaryotic hosts. Therefore, identification of bacterial secreted proteins becomes an important process for the study of various diseases and the corresponding drugs. In this paper, fusing several new features into Chou’s pseudo-amino acid composition (PseAAC), two support vector machine (SVM)-based ternary classifiers are developed to predict secreted proteins of Gram-negative and Gram-positive bacteria. For the two types of bacteria, the high accuracy of 94.03% and 94.36% are obtained in distinguishing classically secreted, non-classically secreted and non-secreted proteins by our method. In order to compare the practical ability of our method in identifying bacterial secreted proteins with those of six published methods, proteins in Escherichia coli and Bacillus subtilis are collected to construct the test sets of Gram-negative and Gram-positive bacteria, and the prediction results of our method are comparable to those of existing methods. When performed on two public independent data sets for predicting NCSPs, it also yields satisfactory results for Gram-negative bacterial proteins. The prediction server SecretP can be accessed at http://cic.scu.edu.cn/bioinformatics/secretPV2/index.htm.     

Synthesis and antimicrobial activity of polyhalobenzonitrile quinazolin-4(3H)-one derivatives

A novel series of polyhalobenzonitrile quinazolin-4(3H)-one derivatives were synthesized and characterized by NMR, IR, MS, and HRMS spectra. All of the newly prepared compounds were screened for antimicrobial activities against four strains of bacteria (Gram-positive bacterial: Staphylococcus aureus and Bacillus cereus; Gram-negative bacterial: Escherichia coli and Pseudomonas aeruginosa) and one strain of fungi (Candida albicans). Among the synthesized compounds, 5-(dimethylamino)-8-(2,4,5-trichloro-isophthalonitrile) quinazolin-4(3H)-one (7k) exhibited significant activity towards Gram-positive bacterial, Gram-negative bacterial, and the fungi strains. The MIC (0.8–3.3 μg/mL) and MBC (2.6–7.8 μg/mL) for this compound were close to those of nofloxacin, chlorothalonil, and fluconazole, making it the most potent antimicrobial agents in the series.     

Protein phylogenies and signature sequences: evolutionary relationships within prokaryotes and between prokaryotes and eukaryotes

The evolutionary relationships within prokaryotes and between prokaryotes and eukaryotes is examined based on protein sequence data. Phylogenies and common signature sequences in some of the most conserved proteins point to a close evolutionary relationship between Archaebacteria and Gram-positive bacteria. The monophyletic nature and distinctness of the Archaebacterial domain is not supported by many of the phylogenies. Within Gram-negative bacteria, cyanobacteria are indicated as the deepest branching lineage, and a clade consisting of Archaebacteria, Gram-positive bacteria and cyanobacteria is supported by signature sequences in many proteins. However, the division within the prokaryotic species viz. Archaebacteria Gram-positive bacteria Cyanobacteria other groups of Gram-negative bacteria, is indicated to be not very rigid but, instead is an evolutionary continuum. It is expected that certain species will be found which represent intermediates in the above transitions. By contrast to the evolutionary relationships within prokaryotes, the eukaryotic species, which are structurally very different, appear to have originated by a very different mechanism. Protein phylogenies and signature sequences provide evidence that the eukaryotic nuclear genome is a chimera which has received major contributions from both an Archaebacterium and a Gram-negative bacterium. To explain these observations, it is suggested that the ancestral eukaryotic cell arose by a symbiotic fusion event between the above parents and that this fusion event led to the origin of both nucleus and endoplasmic reticulum. The monophyletic nature of all extant eukaryotic species further suggests that a 'successful primary fusion' between the prokaryotic species that gave rise to the ancestral eukaryotic cell took place only once in the history of this planet.