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中性柠檬酸菌对几种常见藻类生长的他感作用 总被引:11,自引:0,他引:11
在4500~4800lux光照,26~28℃的培养条件下,从绿裸藻(Euglenaviridis)水华中分离的优势菌种之一中性柠檬酸菌(Citrobacterintermedius)的分泌物对斜生栅藻(Scenedesmusobliquus)、粉核小球藻(Chlorelapyrenoidosa)、羊角月牙藻(Selenastrumcapri cormutum)、水华鱼腥藻(Anabaenaflos-aquae)和易变鱼腥藻(Anabaenavqriabilis)的生长有促进作用;对银灰平裂藻(Merismopediaglauca)、莱茵衣藻(Chlamydononasreinhardi)和铜绿微囊藻(Microcystisaerugiuosa)的生长具有抑制作用。中性柠檬酸菌胞外分泌物能促进粉核小球藻细胞个体的长大,对其他藻类主要是影响细胞的大小。中性柠檬酸菌对不同藻类影响的差异对水华过程可能具有重要意义。 相似文献
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目前养殖的龟类主要有乌龟 (Chinemysreevesii)、黄喉拟水龟 (Mauremysmutica)、三线闭壳龟 (Cuoratrifasciata)等国产龟及国外引进的红耳龟 (Trachemysscriptaelegans)。我们在广州市清平市场经常看见很多从东南亚等地进口的龟类销售 ,如安布闭壳龟 (Cuoraamboinensis)、安南龟(Annamemysannamensis)和眼斑图龟 (Graptemysoculifera)等。为探求此类乌龟是否有人工养殖的价值 ,从 1997年开始 ,我们在校内爬行… 相似文献
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从中华鳖病病鳖的肝脏分离得到菌株s-1。用菌株S-1进行人工感染,100%的鳖患病,从感染的病鳖的肝脏分离到菌株s’-1,经生理生化反应测定,它与菌株s-1特性一致。经鉴定,菌株s-1是迟钝爱德华氏菌,野生型。爱德华氏菌感染会引起鳖的脏器发生变质性病变。主要症状呈肝脏型,肝局部坏死,有结节状肉芽肿。 相似文献
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江西三种红鲤起源与遗传多样性研究的进展 总被引:10,自引:3,他引:10
遗传多样性 (geneticdiversity)是生物多样性的重要组成部分。广义的遗传多样性是指地球上所有生物携带的遗传信息的总和。这里指的遗传多样性主要是指种内不同群体之间或一个群体内不同个体之间的遗传变异的总和 ,这或许可称是遗传多样性狭义的定义[1] 。产于江西省婺源县的荷包红鲤 (Cyprinuscarpiovar.wuyuanensis)、兴国县的兴国红鲤 (Cyprinuscarpievar.xingguonensis)和万安县的玻璃红鲤 (Cyprinuscarpiovar.wananensis)是我… 相似文献
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多种接种途径对翘嘴鳜细菌性烂鳃和败血症的免疫预防效果 总被引:6,自引:0,他引:6
多种接种途径对翘嘴鳜细菌性烂鳃和败血症的免疫预防效果陈昌福,周文豪(华中农业大学水产学院,武汉430070)陈昌福等(1995)先后用从患细菌性烂鳃病的翘嘴鳜(SinipercachuatsiB.)上分离的柱状嗜纤维菌(Cytophagacolumn... 相似文献
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评《Freshwater Fish Culture in China:Principles and Practice》《FreshwaterFishCultureInChina:PrinciplesandPractice}(中国淡水鱼类养殖原理与实践... 相似文献
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广西沿海文蛤及其生境中细菌菌群的初步调查 总被引:15,自引:0,他引:15
对广西沿海文蛤及其养殖场的细菌菌群用VITEK微生物自动分析仪进行了初步检测,发现文蛤体内有腐败假单胞菌(Alteromonasputrefaciens)、河弧菌(Vibriofluvialis)、副溶血弧菌(V.parahaemolyticus)、溶藻弧菌(V.alginolyticus)、非发酵性革兰氏阴性芽胞菌(NonfermentingGram-negativeBacillus)、假单胞菌属(Pseudomonasspp.)以及一些未知菌。从海水中亦经常检测到腐败假单胞菌、溶藻弧菌、河弧菌、温和气单胞菌(Aeromonassobria)等细菌。分析表明,副溶血弧菌可能为文蛤的一种病原菌。药敏试验显示.上述所有细菌几乎都对环丙沙星、庆大霉素和氯霉素敏感。 相似文献
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克雷伯氏菌胞外多糖的制备与组成分析 总被引:1,自引:0,他引:1
利用不同血清型的克雷伯氏菌Klebsiella菌株液体发酵,制备胞外多糖,并采用气相色谱和化学分析方法分析胞外多糖的化学组成。结果表明,菌株K26产胞外多糖的能力最高,培养48h和72h的产量分别为3.11mg/ml和3.89mg/ml;各实验菌株的胞外多糖的单糖组成包括甘露糖、葡萄糖和半乳糖。 相似文献
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A M Declercq F Boyen W Van den Broeck P Bossier A Karsi F Haesebrouck A Decostere 《Journal of fish diseases》2013,36(1):45-55
Flavobacterium columnare is the causative agent of columnaris disease in diverse fish species worldwide. Although columnaris is an important disease, the antimicrobial susceptibility pattern of F. columnare is not well studied. Thus, the purpose of this study was to test the in vitro antimicrobial susceptibility of 97 F. columnare isolates collected worldwide between 1987 and 2011 from 17 fish species. The broth microdilution technique was utilized for reliable testing of these fastidious organisms. None of the isolates displayed acquired resistance to florfenicol, gentamicin, ormetoprim‐sulfadimethoxine and trimethoprim‐sulfamethoxazole. Acquired resistance to chloramphenicol was detected in 1%, to nitrofuran in 5%, to oxytetracycline in 11% and to enrofloxacin, flumequine and oxolinic acid in 10%, 16% and 16% of the isolates, respectively, as reflected by a bimodal or trimodal distribution of their minimum inhibitory concentrations (MICs). One isolate showed acquired resistance towards several antimicrobial agents including erythromycin. Another isolate revealed acquired resistance towards – amongst others – ampicillin. The isolates displaying acquired resistance originated from ornamental fish species or Vietnamese catfish, except for two isolates coming from wild channel catfish in which acquired resistance was encountered towards oxytetracycline only. Fifty per cent of the resistant isolates from ornamental fish were shown to have acquired resistance against three classes of antimicrobial agents, assigning these isolates as multiple resistant. These data might indicate less prudent use of antimicrobials especially in ornamental fish species. 相似文献
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A trial was performed to evaluate the efficacy of diquat (6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide) against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus . Diquat is an Environmental Protection Agency-approved herbicide and has the potential to be legally and practically used against columnaris. Channel catfish were challenged, by cutaneous abrasion, and waterborne exposure to F. columnare and treated once at 22-h post-challenge with 2.5, 5.0, 10.0 and 15 mg L−1 of diquat active ingredient for 6 h. At the conclusion of the trial, 21-day post-challenge, diquat at 5.0, 10.0 and 15 mg L−1 significantly ( P < 0.05) reduced the mortality of infected fish from 95% in the challenged non-treated fish to 68%, 59% and 49%, respectively. In vitro , the minimum inhibitory concentration (MIC) of 23 isolates of F. columnare was assayed. The majority of the isolates had an MIC value of 5 μg mL−1 (15 of the 23 isolates). Infected fish exhibited acute clinical signs similar to a natural infection. The skin had severe ulcerative necrotizing dermatitis and the muscles had severe necrotizing myositis. The gills had severe multifocal necrotizing branchitis. The results demonstrate that diquat would reduce mortalities caused by an acute columnaris infection. 相似文献
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柱状黄杆菌间接ELISA快速检测方法的研究 总被引:1,自引:0,他引:1
应用间接酶联免疫吸附试验(Indirect-ELISA)技术,建立了快速检测柱状黄杆菌的方法。结果显示:根据棋盘试验,确定最佳抗原包被浓度和免疫血清最佳工作浓度分别为1×106cfu/mL和1∶5000,酶标抗体最佳工作浓度为1∶10000。在该条件下,所建立的间接ELISA能检测出5×104cfu/mL的柱状黄杆菌,且与爱德华氏菌、哈维氏菌弧菌、嗜水气单胞菌、副溶血弧菌等常见鱼类致病菌无交叉反应。结果表明,所建立的间接ELISA可不经细菌培养而直接检测人工感染后草鱼鳃组织中的柱状黄杆菌,该方法对柱状黄杆菌的检测具有快速、敏感、特异、实用的优点。 相似文献
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Provisional epidemiological cutoff values for standard broth microdilution susceptibility testing of Flavobacterium columnare
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The gliding aquatic bacterium Flavobacterium columnare causes columnaris disease, a common problem for wild and farmed freshwater fish worldwide. Recently, a broth microdilution method was standardized to test the susceptibility of F. columnare against antimicrobials commonly used in aquaculture. We used this new method to measure the minimal inhibitory concentrations (MICs) of ten antimicrobials against 120 F. columnare isolates. The resulting MIC frequency distributions for each antimicrobial (1 MIC/isolate) were used to estimate epidemiological cut‐off values (ECVs) which separate isolates with typical wild‐type (WT) susceptibility from isolates with decreased non‐wild‐type (NWT) susceptibility. We identified 22 NWT isolates with elevated MICs relative to the ECV that covered 99.9% of the MIC distribution against one or more of the antimicrobials: ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, oxolinic acid or oxytetracycline. Ten of the NWT isolates had decreased susceptibility to a single antimicrobial class, six isolates to two antimicrobial classes and six isolates to three or more antimicrobial classes. The MIC frequency distributions and provisional cut‐off values provide data needed to set epidemiological cut‐off values to monitor for the development of antimicrobial resistance among F. columnare. 相似文献
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The biochemical, serological and molecular characteristics of a group of 21 Edwardsiella tarda strains isolated from turbot, Psetta maxima, in two different areas of Europe were analysed and compared with a total of 13 strains of this bacterial species with different geographical and host origins. All the turbot isolates were biochemically identical to the E. tarda strains included as reference. The use of different techniques including microagglutination, dot blot and Western blot of lipopolysaccharides allowed us to determine that all the turbot isolates constitute an homogeneous and distinctive serological group. Genetic analysis by randomly amplified polymorphic DNA (RAPD) analysis demonstrated that although the E. tarda strains from turbot were compiled in a unique group using the primers P3 and P6, two clonal lineages could be detected when oligonucleotides P4 and P5 were employed. 相似文献
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Abstract. Infectivity of Flexibator columnaris to loach, Misgurnus anguillicaudatus (Blecker, Günther), was studied with variation conditions and the presence of other bacteria in the water medium. Invasion of fish by the poathogen varied with different water conditions. The highest prevalence of infection was observed in an experimentally formulated water containing 0·03% NaCl 0·01% KCl, 0·002% CaCl2 2H2 O and 0·004% MgCI2 6H2 O. The percentage of infection in tap water was similar to that of the formulated water. The infeetion rate was low in the individual salt solutions, and no infection occurred in distilled water. Even in the formulated water, the pathogen failed to infect the fish when Citrobacter freundii, Aeromonas hydrophila or Pseudomonas fluorescens were present at densities 100 times that of F. columnaris. However, in such cases, the numbers of F. columnaris in the mucus of the fish body surface did not increase much throughout the experimental period. In contrast, F. columnaris suceessfully invaded the fish in the presence of either Streptococcus sp., Flavobacterium flavescens or Flavobacterium fuscum , even when the numbers of these bacteria were 1000 times that of F. columnaris. In this ease, F. columnaris gradually increased its numbers on the fish body surface. 相似文献