中华绒螯蟹养殖期间细菌性疾病流行情况调查研究

1999~2004年对安徽省巢湖市6个乡镇的池塘、稻田养殖的中华绒螯蟹(Eriocheir sinensis)的细菌性疾病流行情况进行了调查研究。结果表明:中华绒螯蟹细菌性疾病发生与流行存在着季节性,其发病率年平均依次为47.3%、59.6%、51.9%、46.7%、60.0%、29.9%,逐月比较发病率最大峰值出现在每年的8月份;感染率年平均分别为66.6%、75.8%、57.8%、52.0%、86.0%、39.3%,死亡率年平均依次为38.3%、44.6%、36.3%、29.6%、43.5%、21.6%;中华绒螯蟹细菌性疾病发病率与出现的最高气温、最低气温以及气温、水温持续偏高呈正相关(r=0.7657、r=0.7385、r=0.7237,P<0.01)。     

Analysis of exotoxins produced by atypical isolates of Aeromonas salmonicida,by enzymatic and serological methods

In this study, exotoxins produced by 62 Aeromonas salmonicida strains and the bacterium Haemophilus piscium were analysed. Enzymatic assays, zymograms and serological detection were used to monitor secretion by bacterial strains of the previously described exotoxins P1, GCAT and AsaP1 and also the extracellular P2 metallo-gelatinase and a serine caseinase, which is different from the P1 protease and has not yet been characterized. Based on the results, the strains were divided into five groups. One comprised the type strains for A. salmonicida ssp. masoucida, H. piscium and 36% of the atypical isolates, and another, a type strain for A. salmonicida ssp. smithia together with 14% of the atypical isolates. A second type strain of A. salmonicida ssp. smithia was grouped with 8% of the atypical isolates. The largest group contained the type strains for A. salmonicida ssp. achromogenes and 38% of the atypical isolates. The type strains for A. salmonicida ssp. salmonicida were in the last group with all the four typical strains and 4% of the atypical isolates. The combination of zymogram and serological detection used is recommended as the most reliable method for characterizing A. salmonicida strains according to their exotoxin secretion.     

Bioencapsulation of five forms of erythromycin by adult Artemia salina (L.)

Uptake of five chemical forms of erythromycin by adult Artemia salina (L.) (erythromycin phosphate – EP, erythromycin stearate – ES, erythromycin estolate – EE, erythromycin hydrate – EH and crystalline erythromycin – CE) was investigated in two trials. In each trial, final erythromycin concentration in Artemia tissue and survival after a 12‐h bioencapsulation period were determined. In the first trial, Artemia tissue concentration after a 12‐h bioencapsulation period was significantly (P < 0.05) affected by erythromycin form with ES (68.5 ± 3.3 μg mL^?1, mean ± SEM) ≈ EH (61.2 ± 3.4 μg mL^?1) > CE (37.1 ± 10.7 μg mL^?1) > EP (16.4 ± 7.7 μg mL^?1) > control. In trial 2, Artemia tissue concentration was also significantly (P < 0.05) affected by erythromycin form with EE (111.4 ± 9.6 μg mL^?1) > CE (89.1 ± 1.7 μg mL^?1) > ES (78.9 ± 1.6 μg mL^?1) > EP (33.4 ± 5.2 μg mL^?1) > control. Survival was significantly affected by erythromycin form in trial 1 with EP=control (100 ± 0.0%) > ES (74.4 ± 2.0%) > CE (32.2 ± 0.3%) > EH (8.8 ± 4.4%). In trial 2, survival was also significantly affected by erythromycin form with EP=control (100 ± 0.0%) > ES (67.1 ±3.7%) > CE (52.5 ± 7.7%) > EE (5.0 ± 2.5%). Based on both uptake and survival, EP and ES appear to be appropriate compounds for bioencapsulation of erythromycin using live adult Artemia.     

Bacterial flora associated with the giant freshwater prawn Macrobrachium rosenbergii, in the hatchery system

The objective of this study was to understand the microbial flora associated with the hatchery system of giant fresh water prawn, Macrobrachium rosenbergii during an entire rearing cycle. Bacteriological and physico-chemical analysis was done for different samples of water, larvae, and Artemia. The total bacterial load in well water, seawater and inlet water varied from 10¹ to 10⁵ cfu ml^− 1 with higher counts seen in larval rearing tank (LRT) water. The Vibrio count ranged between 10¹ to 10³ cfu ml^− 1. Larval samples harboured a bacterial load of 10⁶ to 10⁷ cfu/10 larvae. The bacterial load in Artemia hatching water ranged from 4.90 × 10⁴ to 5.63 × 10⁶ cfu ml^− 1 while Artemia had a load ranging from 1.08 × 10⁷ to 2.09 × 10⁹ cfu g^− 1. Vibrio count in the LRT water ranged from 10¹-10³ cfu ml^− 1 while the count in larvae ranged from 10² to 10⁴ cfu/10 larvae. The bacterial genera were predominantly Gram-negative and comprised of Aeromonas spp., Pseudomonas spp., Vibrio spp. and Bacillus spp. and non-spore formers (NSF) were the dominant Gram-positive bacteria. This study documents the bacterial flora associated with Macrobrachium hatchery system during a regular normal run. Knowledge of the qualitative and quantitative aspects of bacterial flora in the hatchery would help to understand disturbances, if any, brought about during disease outbreaks.     

维氏气单胞菌菌影疫苗的构建及其溶菌动力学研究

细菌菌影(Bacterial ghosts)是通过诱导PhiX 174噬菌体中裂解基因E在革兰氏阴性菌中的表达所获得的无细胞内容物的空细菌体.它保持了与活菌相同的膜蛋白成分、天然结构、细胞表面抗原等特性,是一种新型的死菌疫苗.为优化维氏气单胞菌(A.veronii)菌影制备条件,本实验将带有庆大抗性的裂解基因E转入A.veroniiATCC35624株中,通过温度变化对其进行溶菌动力学试验,每隔30 min对菌液OD600nm及其活菌数进行测定,当OD600nm稳定不再下降时,通过扫描电镜观察裂解后菌体的形态变化.结果显示,在诱导30 min后OD600nm值开始持续下降,当其下降到最低值时,活菌检测结果表明几乎无活菌存在.本研究利用菌影形成机制构建A.veronii菌影,为新型疫苗的制备提供依据.     

鲈细菌性类结节病的病原及血液病理研究

2002年5月从患细菌性类结节病的濒死鲈体内分离到一株细菌02517-1，经人工感染试验及API 20E系统鉴定，认为该病原菌为嗜水气单胞菌(Aeromonas hydrophila)。血液生理生化指标检测显示，与健康鱼相比，患病鱼的红细胞、白细胞、血糖、蛋白质、尿素、胆固醇等显著下降，而谷丙转氨酶ALT、谷草转氨酶AST、乳酸脱氢酶LDH等血清酶类活性增强，说明经嗜水气单胞菌感染后，鲈在营养物质代谢、抗病力、消化、呼吸、排泄等方面的生理功能受到严重损害。药敏实验结果表明：复方新诺明、卡那霉素、庆大霉素、氟哌酸等4种化学疗剂及地榆、乌梅、木瓜、五味子等4种中草药对该种病原菌有较强的抑菌作用。     

Determination of bacteria constituting ruminal fibrolytic consortia developed on orchard grass hay stem

To determine the relationship between Fibrobacter succinogenes and other rumen bacteria, the bacterial community structure on fiber was analyzed by using two different materials. These were ruminally incubated orchard grass hay stems without and with preincubation with F. succinogenes (natural and artificial consortia, respectively). The natural consortium mainly consisted of Firmicutes (56.6%) and Bacteroidetes (33.1%), while the artificial consortium showed a significantly higher proportion of Firmicutes (85.5%) and a lower proportion of Bacteroidetes (4.6%). At species or genus level, Butyrivibrio fibrisolvens, the U2 group, Ruminococcus albus and Lachnospiraceae incertae sedis made up a higher proportion in the artificial consortium. The most dominant bacterial group was the Butyrivibrio‐Pseudobutyrivibrio‐Lachnospiraceae incertae sedis group, which accounted for 19.7% in the natural and 29.5% in the artificial consortium. Within the genus Butyrivibrio, the phylogenetic groups SA and VA2 and phylogeny‐undefined Butyribivrio, but not VA1, were detected at high frequency in the artificial consortium. These results suggest that ecological and possibly functional relationships exist in the rumen among F. succinogenes, a subset of B. fibrisolvens, the U2 group, R. albus and Lachnospiraceae incertae sedis.     

重庆开县猕猴桃溃疡病药效试验研究初报

猕猴桃溃疡病是毁灭性病害,目前化学防治是预防该病的主要措施。试验采用碧生20％（噻唑锌）悬浮剂、可杀得1 01、农用链霉素72％可溶性粉剂、1．8％辛茵胺和有机硅对猕猴桃溃疡病防治进行药效研究。结果表明,蓰用链霉素72％可溶性粉剂1 000倍液对猕猴桃溃疡病防治效果最好,碧生20％（噻唑锌）悬浮剂、可杀得1 01、1．8％辛菌胺防治效果其次,且这5种药剂之间药效差异不显著。     

软包装即食醉鱼制品细菌学品质安全分析

对上海市场常见品牌的软包装即食醉鱼制品感官、理化、细菌学品质状况进行定性和定量研究,并对潜在病原菌安全性进行评价。结果表明,产品水分含量、水分活度、pH和盐分含量分别为43.50%~56.97%,0.93~0.97,6.07~6.73,2.41%~6.63%,差别较大;细菌菌落总数、耐热菌落总数分别是1.8×102~4.2×105cfu/g,38~3 800 cfu/g;厌氧菌落总数和金黄色葡萄球菌均低于10 cfu/g。由细菌总数计数平板分离256株细菌,鉴定残存主要细菌菌群为芽孢杆菌(34.0%)、葡萄球菌(27.3%)、玫瑰小球菌(14.0%),并出现少量的棒状杆菌(5.5%),表明热杀菌强度不足。产品中残存有一定数量的蜡样芽孢杆菌,对其潜在危害有待进一步研究。     

4个番茄品种对细菌性斑点病田间抗性评价及摘叶法防治技术初探

对云南热区4个番茄品种进行了细菌性斑点病的田间抗性评价和发病特点调查,同时评价了人工摘除病叶法对该病的防治效果。结果表明,拉比品种抗病性优于其它3个品种,同一品种植株上各部位发病严重程度依次为下部＞中部＞上部。用20%噻菌铜SC 300倍液进行病害防治时,辅以人工摘除下部重病叶的措施可显著提高病害防治效果。