Granulomatous lesions in a wild mullet population from the eastern Ligurian Sea (Italy): mycobacteriosis vs. pseudotuberculosis

Mycobacterium spp. and Photobacterium damselae subsp. piscicida are recognized as the most frequent causative agents of granulomatous lesions in fish. Although frequent episodes of mycobacterial infections have been reported in wild fish worldwide, only sporadic cases have been documented to date in Italy. To investigate for the presence of lesions referable to mycobacteriosis and to identify the mycobacterial species involved, a total of 159 wild mullets were fished from the eastern coast of the Ligurian Sea, killed and necropsied. Liver and spleen samples were collected from all fish for histopathological and microbiological analyses. Molecular investigations for identification of Photobacterium damselae subsp. piscicida were performed. Gross examination revealed granulomatous lesions in one animal; microscopically, 42.14% of fish displayed granulomas with various histological features, 19.50% resulted positive at Ziehl–Neelsen staining, and were confirmed as mycobacterial lesions by culture. The identified colonies were characterized as M. fortuitum, M. abscessus, M. flavescens, M. chelonae, M. septicum and M. nonchromogenicum. In all, 35% of animals resulted positive for Photobacterium damselae subsp. piscicida. These data suggest widespread mycobacterial infection also by Photobacterium damselae subsp. piscicida infections in wild fish. Moreover, the pathogenicity of some mycobacterial species, previously considered as saprophytic, was demonstrated.     

The in‐vitro antibacterial effects of organic salts,chemical disinfectants and antibiotics against pathogens of black disease in fairy shrimp of Thailand

The antibacterial effects of organic salts, chemical disinfectants and antibiotics were evaluated on cultures of Aeromonas hydrophila C03, Aeromonas sobria C26, A. sobria C29, Aeromonas caviae C24 and Acinetobacter sp. SH‐94B, the pathogens that cause black disease found in fairy shrimps (Streptocephalus sirindhornae Sanoamuang et al. (2000) and Branchinella thailandensis Sanoamuang, Saengphan & Murugan) of Thailand. The minimal inhibitory concentrations (MICs) of organic salts (sodium chloride and potassium chloride) and antibiotics (oxytetracycline dihydrate, streptomycin sulphate, kanamycin monosulphate, chloramphenicol and ampicillin) were determined using the agar‐dilution method. The effect of chemical disinfectants (sodium hypochlorite and chlorine dioxide) was evaluated by exposing bacteria to different concentrations of these chemicals for different periods of time. Interestingly, all strains were intrinsically resistant to 0.25–3% sodium chloride and potassium chloride. The effect of sodium hypochlorite was greater than that of chlorine dioxide, and 5–20 μg mL^?1 of sodium hypochlorite was sufficient to inhibit the growth of these bacteria, but the exposure time varied, depending on the bacterial species. Of the antibiotics tested, chloramphenicol and oxytetracycline dihydrate completely inhibited the selected strains. Chloramphenicol showed the highest antibacterial effect against all pathogenic species – the MIC and minimal bactericidal concentration (MBC) ranged from 0.8 to 3.1 μg mL^?1 from 3.1 to 6.25 μg mL^?1, respectively. To achieve control of black disease during cultivation of fairy shrimp, data derived from this study can be used as a basis for further toxicity tests in vivo.     

基于文献计量统计分析中国棉花研究学术发展

运用文献计量方法,以SCIE数据库为数据源基础,检索了有关棉花研究的文献,从文献量、学科、期刊、著者和引文等角度进行了统计和分析,以定量数据从侧面反映10多年来中国棉花研究领域学术发展状况,揭示了中国加入WTO后棉花研究领域的蓬勃发展态势,年载文量稳步快速增长,学科研究领域广泛,基础科学研究取得了长足进步,国际交流与合作普遍,形成了较强的棉花研究团队,具有较强的学术研究领军人物,带动了中国棉花学术领域的发展。     

龙葵等19种野生植物提取物的离体抑菌活性研究

研究大庆地区19种具有清热、解毒功能的野生植物对小麦赤霉病(Fusarium graminearum)等5种常见植物病原真菌的抑菌活性。制备参试植物乙醇提取液,采用生长速率法测定提取液对5种病原菌的抑菌活性。筛选出对至少1种供试病原真菌有65%以上抑菌效果的植物样品6种。龙葵全株提取物对所有病原真菌均有很好的抑制作用,对小麦赤霉病菌抑制率为78.31%,对玉米圆斑病菌抑制率为84.87%;野亚麻根提取物对3种病原真菌有较好的抑制作用,对玉米圆斑病菌抑制率为73.94%、水稻纹枯病菌抑菌率为72.7%。龙葵及野亚麻乙醇提取物对大部分参试植物病原真菌具有较高抑制活性;汉麻、苍耳、菊芋对5种参试病原菌均有不同程度的抑菌活性。     

陕西设施蔬菜根结线虫特异性分子检测

为明确陕西设施蔬菜根结线虫的主要种类,利用已报道的花生根结线虫[Meloidogyne arenaria (Neal.) Chitwood]、南方根结线虫[Meloidogyne incognita (Kofold & White) Chitwood]、北方根结线虫(Meloidogyne hapla Chitwood)和爪哇根结线虫[Meloidogyne javanica (Treub)]的特异性引物,对陕西省20个县市区的24个样区的根结线虫进行PCR检测。样品中检测到了南方根结线虫、北方根结线虫、花生根结线虫和爪哇根结线虫,其中南方根结线虫为优势种群,大部分样区为单一种群为害,但个别样区存在2种种群。     

河南省某地区健康人源及动物源肠球菌种属分布及耐药性差异研究

为了解河南省某地区社区健康人源及动物(鸡、猪)源肠球菌种属分布及对多种抗菌药物的耐受情况,以及研究不同来源肠球菌的流行分布和抗菌药物耐药表型特点,本试验应用肠球菌选择性培养基对220份人源及动物源粪便样本进行肠球菌的分离培养,并对分离菌株采用16S rDNA序列分析结合API生化板条进行种属鉴定,纸片扩散法对分离肠球菌进行9种抗菌药物的敏感性检测.肠球菌分离及鉴定结果显示肠球菌总分离率、粪肠球菌分离率及屎肠球菌分离率在人源、鸡源、猪源3种来源间均差异显著(P<0.05):肠球菌总分离率为70.91%(156/220),猪源肠球菌分离率最高(86.00%),人源肠球菌分离率最低(62.63%),且人源与猪源肠球菌分离率差异显著(P<0.018);人源粪便样本中分离率最高的为屎肠球菌(31.36%),鸡源、猪源肠球菌中粪肠球菌分离率最高,分别为28.17%和32.00%.抗菌药物敏感性结果显示肠球菌对多种药物的耐药率在人源、鸡源、猪源3种来源间差异显著(P<0.05),且3种来源肠球菌的多药耐药率差异有统计学意义(P<0.05).人源肠球菌对红霉素(69.35%)、环丙沙星(37.10%)、氨苄西林(19.35%)等抗菌药物耐药率较其他来源的肠球菌要高;鸡源肠球菌对四环素(88.24%)、氟苯尼考(11.76%)、氯霉素(21.57%)等抗菌药物耐药率较其他来源的肠球菌要高;猪源肠球菌对抗菌药物耐药率总体较低,且其多药耐药率(7.84%)也低于人源(35.48%)及鸡源肠球菌(30.19%).提示,健康人及动物粪便样本中肠球菌种属分布不同及对抗菌药物耐药率有差别,并对多种常见抗菌药物耐药率较高,有关部门应加强社区人群及动物等非临床来源肠球菌耐药检查、监测,进而更好的了解中国耐药肠球菌的流行现状,更有效的控制耐药肠球菌的传播.     

杨树扦插繁殖理论与技术概述

从亲本的条件与生根能力、插穗的条件与生根能力、插床环境条件与生根的关系、生根促进物质及防腐剂的使用方法研究等国内外繁殖技术研究以及母株复壮、插条生根的形态解剖学和生理生化机理研究状况进行了概述．对杨树扦插繁殖技术与发展现状作了简单的评述．     

甘肃连城国家级自然保护区4种云杉属植物表型变异比较研究

对甘肃连城国家级自然保护区白青杆、青海云杉等4种类型云杉属植物种子长、针叶长等10个表型性状采用方差分析、相关分析和聚类分析等方法,分析这4种类型植物的表型多样性,以便对该保护区内分类地位不明确的麻衣松进行分类地位的确定．结果表明,白青杆和黑青杆的表型多样性比较丰富,4种类型的平均变异系数由大到小依次为黑青杆、白青扦、麻衣松和青海云杉．白青杆和黑青杆的表型性状间大多数呈极显著或显著相关,麻衣松和青海云杉的大多数表型性状间相关性不显著．用分层聚类的方法分别对4种类型的表型性状进行聚类分析,结果表明,白青杆和黑青杆的表型性状可分为4类,麻衣松和青海云杉的表型性状可分为3类;麻衣松与白青杆、黑青杆不属于同一类,而与青海云杉比较相近．