Vibrio anguillarum and larval mortality in a California coastal shellfish hatchery.

Vibrio anguillarum was isolated as a pathogen in the commercial culture of oyster spat at Pigeon Point, Calif. A water-soluble, heat-stable exotoxin extracted from cultures of the vibrio inhibited larval swimming and contributed to larval mortality. Although the vibrio was insensitive to penicillin in standard plate testing, this antibiotic proved useful in preventing mass larval mortalities in the hatchery.     

副溶血性弧菌显色培养基检测效果初步评价

副溶血性弧菌(Vibrio parahaemolyticus)是一种重要的食源性致病菌,广泛存在于各种海产品中.由于传统培养基和检测方法费时费力,本研究设计开发了一种新型显色培养基HKC vibrio,通过应用于人工污染样品和实际样品检验,以法国科玛嘉弧菌显色平板CHROMagar vibrio和柠檬酸钠-硫代硫酸钠-氯化钠-蔗糖琼脂平板(TCBS)为对照,对显色培养基HKC vibrio的灵敏性、特异性和检测效果进行了初步评价.结果表明,HKC vibrio的灵敏性与CHROMagar vibrio和TCBS相当,并具有较好的特异性,HKC vibrio是非常有价值的分离平板,可大大提高副溶血性弧菌的检测效率.     

副溶血性弧菌显色培养基检测效果初步评价

副溶血性弧菌(Vibrio parahaemolyticus)是一种重要的食源性致病菌, 广泛存在于各种海产品中。由于传统培养基和检测方法费时费力, 本研究设计开发了一种新型显色培养基HKC vibrio, 通过应用于人工污染样品和实际样品检验, 以法国科玛嘉弧菌显色平板CHROMagar vibrio和柠檬酸钠-硫代硫酸钠-氯化钠-蔗糖琼脂平板(TCBS)为对照, 对显色培养基HKC vibrio的灵敏性、特异性和检测效果进行了初步评价。结果表明, HKC vibrio的灵敏性与CHROMagar vibrio和TCBS相当, 并具有较好的特异性, HKC vibrio是非常有价值的分离平板, 可大大提高副溶血性弧菌的检测效率。     

Immunochemical Studies on Lipopolysaccharide from Agglutinable and Non-Agglutinable Vibrios

Lipopolysaccharide (LPS) prepared from Vibrio cholerae and a non-agglutinable (NAG; not agglutinable with O-group I serum according to Gardner and Venkatraman [13]) vibrio strain, isolated from a patient with cholera-like clinical symptoms, have been compared with respect to their chemical composition and immunological behavior. In addition to a significant difference in the chemical composition between the two lipopolysaccharides, the LPS from V. cholerae, unlike that from the NAG vibrio, requires prior treatment with alkali for it to be an effective antigen in the indirect hemagglutination test with sheep cells. It has been suggested that the alkali acts by removing excess O-acetyl group from LPS of agglutinable vibrios. LPS from the NAG vibrio consistently showed a lower antibody response in rabbits in terms of agglutinin and vibriocidal titer. Also, the class of agglutinin antibody elicited by LPS of the NAG vibrio was predominantly immunoglobin M, and that from V. cholerae was immunoglobulin G under comparable conditions.     

The effect on enterotoxicity of protease purified from Vibrio cholerae O1

Abstract The effect on enterotoxicity of protease purified from Vibrio cholerae O1 was investigated by the inoculation of live vibrio cells into the protease-treated loops of the ileal loop model. Fluid accumulation ratios in the protease-treated loops were elevated in a dose-dependent manner by challenge with live vibrio cells byt not that with toxin. An enhancement effect of protease on enterotoxicity was observed in both serotypes of V. cholerae O1 and V. cholerae non-O1. It is suggested, therefore, that the enterotoxicity was enhanced by treatment with protease when live vibrio cells were inoculated into the ileal loops of rabbits.     

Genomic diversity of vibrios associated with the Brazilian coral Mussismilia hispida and its sympatric zoanthids (Palythoa caribaeorum, Palythoa variabilis and Zoanthus solanderi)

Aims: A taxonomic survey of the vibrios associated with the Brazilian endemic coral Mussismilia hispida and the sympatric zoanthids (i.e. Palythoa caribaeorum, Palythoa variabilis and Zoanthus solanderi). Methods and Results: Mucus of 54 cnidarian specimens collected in three different places at São Sebastião in two consecutive years (i.e. 2005 and 2006) was used for taxonomic characterization of the cnidarian microbiota. Ninety‐eight of the 151 vibrio isolates fell within the vibrio core group according to partial 16S rDNA sequences. We performed the sequencing of recA and pyrH genes of all vibrio isolates. The most abundant taxa belonged to the vibrio core group (Vibrio harveyi, Vibrio rotiferianus, Vibrio campbellii and Vibrio alginolyticus), Vibrio mediterranei (=Vibrio shillonii) and Vibrio chagasii. With the exception of V. chagasii which was found only in the mucus of M. hispida, the other species appeared in different hosts with no evidence for the presence of host‐specific clones or species. Using rep‐PCR analysis, we observed a high genomic heterogeneity within the vibrios. Each vibrio isolate generated a different rep‐PCR fingerprint pattern. There was a complete agreement between the grouping based on rep‐PCR and concatenated sequences of pyrH, recA and 16S rDNA, but the pyrH gene has the highest discriminatory power for vibrio species identification. Conclusion: The vibrio core group is dominant in the mucus of these cnidarians. There is a tremendous diversity of vibrio lineages within the coral mucus. pyrH gene sequences permit a clear‐cut identification of vibrios. Significance and Impact of the Study: The taxonomic resolution provided by pyrH (but not recA) appears to be enough for identifying species of vibrios and for disclosing putative new taxa. The vibrio core group appears to be dominant in the mucus of the Brazilian cnidarians. The overrepresentation of these vibrios may reflect as yet unknown ecological functions in the coral holobiont.     

滩涂海水种植-养殖系统细菌生态学研究

滩涂海水种植-养殖系统是一种新型的生态养殖模式．对种植红树林的滩涂种植-养殖系统中细菌的生物量分布和水质的分析结果表明,由于红树林的净化作用,该系统内的水质达到Ⅱ～Ⅲ类海水水质标准,而对照塘的处于Ⅳ、Ⅴ类水质标准．系统中处理塘的异养菌、弧菌、磷细菌和产酶类细菌的数量比未种红树林的对照塘低1～2个数量级．用CORREL软件分析了细菌与水质的相关关系,异养菌、弧菌、磷细菌和产酶类细菌的数量与水体中的氮磷含量呈正相关．其中异养菌与弧菌的相关系数为0．9205,与氮磷的相关系数为0．6535(N)、0．8342(P),表明异养菌和弧菌可作为滩涂海水养殖系统水质的生物监测指标．     

Characteristics of the heat-stable enterotoxin of NAG vibrios

Cell-free culture filtrate boiled for 15 minutes has been found to retain its biological activity in various experimental models used for the determination of the toxicogenicity of cholera vibrio filtrates. During gel filtration of the concentrated filrate o. NAG vibrio, strain NO. 9852, through Sephadex G-75 toxic activity could be detected in the free volume of the column, which was indicative of the fact that the molecular weight of the thermostable enterotoxin was about 70,000 daltons and greater. The methods of gel diffusion and aggregated hemagglutination have been used to show that the thermostable enterotoxin of NAG vibrio No. 9852 is immunologically unrelated to cholerogen. Some data obtained in experimental models suggest that the thermostable enterotoxin probably differs from cholera enterotoxin in the mechanism of its action.     

Genetic relationship among bacteria classified as vibrios

Genetic relatedness among six bacterial strains currently classified as vibrios was determined by biochemical tests, deoxyribonucleic acid base composition analysis, and the detection of nucleic acid homology by the membrane filter method. Varying degrees of genetic homology existed among vibrios having similar base compositions. The bovine isolate which had a substantially different per cent guanine plus cytosine content was shown to be genetically different from the remaining vibrio strains. The use of nucleic acid homology studies in classifying vibrio strains is discussed.     

Soft-Shell Clam, Mya arenaria, a Convenient Laboratory Animal for Screening Pathogens of Bivalve Mollusks

Attempts to introduce infectious or foreign material into oysters and other bivalve mollusks usually involve force or trauma because of immediate, prolonged adduction of the tightly closing valves. The soft-shell clam, Mya arenaria, is unable to seal its valves completely and relaxes readily, exposing soft tissue and a large siphon. This species is free from fouling organisms and is readily available at all seasons in the New England and mid-Atlantic areas. Suspensions of five strains of Vibrio sp. that cause bacillary necrosis in larval and juvenile bivalve mollusks were injected into the heart, siphon tissue, and the incurrent and excurrent siphon lumina of soft-shell clams. All vibrio strains caused significant mortality, usually within 2 days. Heaviest losses resulted from heart and excurrent siphon injections. No mortality occurred in control clams injected with seawater, broth, Serratia sp., and Escherichia coli. The soft-shell clam appears to be a useful animal for testing the pathogenicity of marine microorganisms for bivalve mollusks.     

Construction of a genetic map of the chromosome of Vibrio cholerae based on conjugational crossings

The results of cholera vibrio chromosomal mapping using Vibrio cholerae classica and V. cholerae eltor donor strains obtained with the help of various R. plasmids, are summarized in the paper. A genetic map of V. cholerae chromosome was established showing the order of 35 gene markers. The relationship between the genetic structures of cholera eltor and classical vibrio biotypes is discussed.     

The agglutinability of cholera O-monoclonal immunoglobulins]

A set of 10 monoclonal antibodies specific for vibrio species and of 5 monoclonal antibodies specific for serovar (Ogawa) was studied. These monoclonal antibodies were directed toward V. cholerae O1 antigen in agglutination reaction and on slide plates. Monoclonal antibodies agglutinating typical strains of cholera vibrios with titration range from 1: 6000 to 1: 25,000 were selected. MA were revealed to interact with cholera vibrio strains with reduced agglutinability. The set of agglutinating O monoclonal immunoglobulins was developed for laboratory identification of cholera O1 vibrios.     

Utilization of serological methods in the retrospective diagnosis of cholera and in detecting vibrion carriers]

Sensitivity and specificity of the three serological methods were studied comparatively: the vibriocidal test, the reaction of bacterial agglutination and of indirect hemagglutination, with the use of erythrocytes sensitized with the vibrio lyzate, cholera species O-antigen and cholerogen. Investigations were conducted with the blood sera of cholera patients, vibrio carriers and contacts. Vibriocidal test proved to be the most sensitive; its data correlated with the results of bacterial agglutination and indirect hemagglutination with erythrocytes, sensitized with the lysate of the vibrios and the cholera O-antigen. None of the used serological methods provided a 100% coincidence with the results of bacteriological analysis. The frequency of detection of anticholera antibodies decreased in the following order: cholera patients, vibrio carriers, contacts.     

九孔鲍养殖水体及其肠道不同菌群抗药性研究*

为更好地防治鲍鱼病害的发生和流行,对分离自广东汕尾健生鲍鱼养殖场九孔鲍养殖环境及其肠道中不同细菌菌群的耐药性进行了研究。结果表明,四环素、青霉素G、卡那霉素、丁胺卡那霉素和新生霉素均对绝大多数异养菌和弧菌菌株都不敏感或无作用;相反,氟哌酸、红霉素、氯霉素以及环丙沙星等则均对它们比较敏感;复方新诺明、链霉素和多粘霉素B对弧菌菌株均有作用,而且多粘霉素B也对水体中的异养菌群相当有效。     

斗门地区养殖水源细菌数量的变化动态

细菌是水体生物群落中的重要组成部分 ,在水生态系统的物质循环中起着重要的作用 ,水环境中的各种因素也直接或间接地影响着细菌的数量和分布。对养殖生产来说 ,有不少细菌是养殖动物的病源 ,因此 ,水体细菌量的变化可作为反映水环境及水质变化的一个指标[7] 。斗门地区地处珠江口西岸 ,是广东省珠海市主要的水产养殖区 ,其养殖水源为河水和地下咸水。本文研究流经斗门地区的螺洲河及地下咸水蓄水池中水体异养细菌的数量变化 ,为了解该地区养殖水源水质变化提供依据。1　材料与方法1 1　调查站位和时间根据调查的需要设 2个水样采样站位 ,每…     

XerCD/dif位点特异性重组

大约10%~15%的大肠杆菌在染色体复制过程中会形成染色体二聚体。大肠杆菌染色体编码的重组酶XerC和XerD作用于染色体复制终点区的dif序列,以同源重组的方式将染色体二聚体解离为单体,使细菌得以正常复制分裂。编码霍乱毒素的噬菌体CTXΦ以位点特异的方式整合入霍乱弧菌染色体,但其基因组中不含有任何重组酶基因,其整合过程需要细菌染色体编码的XerC和XerD重组酶,且整合位点与大肠杆菌dif序列相似。XerCD重组酶基因和dif位点在细菌染色体广泛存在,表明其可能是染色体二聚体解离,噬菌体及其他外源基因成分整合入染色体过程中一种广泛存在的途径。文章对XerCD/dif位点特异性重组在细菌染色体二聚体解离、外源基因整合的研究进展进行综述。     

Antibiotic sensitivity of El Tor Vibrio cholerae after exposure to various pesticides and mineral fertilizers]

The strains of El Tor Vibrio cholerae were exposed to different concentrations of pesticides (fazolone, treflane, prometrine, magnesium chlorate, omait and gardon) and mineral fertilizers (superphosphate, ammophos and carbamide) for 2 to 135 days. The subcultures of various ages were tested for their sensitivity to 16 antibiotics. The whole of 229 cultures were tested. There was a general tendency to lowering of the El Tor vibrio sensitivity to the majority of the antibiotics tested. The vibrio strains resistant to the antibiotics widely used in medical practice i. e. levomycetin, streptomycin, tetracycline, lincomycin, neomycin and kanamycin were isolated.     

Immunity to Cholera: Relation of Fraction II of Type 2 Cholera Toxin to Vibriocidal Antibody

The nontoxic protein component in supernatant fluids of young cultures of the cholera vibrio in peptone dialysate broth contains an antigen identical in specificity to vibrio lipopolysaccharide. This material was heterogeneous after elution from diethylaminoethyl A50 Sephadex, and it contained at least five additional minor antigens. Identity was demonstrated by immunodiffusion methods, by the induction of specific vibriocidal antibody formation, and by specific interference in the vibriocidal reaction. The minor antigens appeared to be unrelated to the vibriocidal reaction. The major antigen was more highly immunogenic than lipopolysaccharide, giving higher and longer-persisting antibody titers in the rabbit, but lipopolysaccharide was the more effective interfering antigen per unit weight in the vibriocidal reaction. The nontoxicity and high immunogenic potency of the protein antigen suggest that it may be useful as an immunizing agent for the production of the antibacterial component of an effective immunity.     

Prediction and experimental testing of ferric uptake regulator regulons in vibrios

Iron homeostasis is in many bacteria regulated by the ferric uptake regulator (Fur). Despite the available information on Fur regulons, it is likely that there are Fur-regulated genes and operons that are unique to vibrios, and knowledge into these can potentially provide new insights into vibrio virulence and pathogenesis. We constructed a vibrio-specific alignment matrix based on Fur-binding sites from the literature and used existing software (Patser) to search five published vibrio genomes and the Vibrio salmonicida draft genome for Fur-regulated genes. The consensus Fur-binding site from our matrix is 5'-AATGANAATNATTNTCATT-3'. Fur-binding motifs were found associated with 50-61 single genes and 16-20 operons in each genome. Predictions were tested by monitoring the expression of a subset of genes and operons in V. salmonicida. Six previously undescribed Fur-regulated genes showed increased expression under iron-restrictive conditions. Our work provides a comprehensive list of predicted Fur regulons in six vibrio genomes, which may be used to generate new hypotheses for future experiments.     

Detection of a Vibrio sp. by the Bacteriophagous Nematode Pelodera chitwoodi

S ummary . Pelodera chitwoodi was able to distinguish between a Vibrio sp. (food bacterium) and Chromobacterium janthinum (non-food bacterium), and between bacteria and mud. Nematodes migrated preferentially to the Vibrio sp. at various distances, temperatures, and pH values. Migration to food bacteria increased with an increase in bacterial concentration. Resting and dead bacteria failed to attract nematodes. Nematodes were able to detect a vibrio colony separated from them by a plastic barrier, and migrated to areas on agar containing exudate and dialysate from the vibrio. Both exudate and dialyzate contained 4 amino acids and 3 vitamins which attracted nematodes. However, attraction of nematodes to these compounds was not as strong as to metabolizing bacteria, indicating that additional compounds were also involved.