光合细菌在水产养殖上的应用研究与进展

光合细菌是一种能进行光合作用的细菌，广泛分布于淡、海水和活性淤泥、土壤中，与水产有着密切的联系。国际上从20世纪50年代开始了光合细菌在水产养殖方面的应用研究。对50年来光合细菌的研究进展及前景作出了阐述。     

海洋光合细菌的分离培养研究

光合细菌是一大类具有光合色素,能在厌氧光照条件下进行光合作用的原核生物的总称。由于光合细菌对鱼类具有明显的促生长作用,还有防治鱼虾疾病、净化养殖水质等多方面的功能近年来普遍受到水产科研部门的重视。我们从1989年开始对这类光合细菌进行了分离、培养,特别在分离、培养适用于海水养殖池的光合细菌菌株方面进行了较多的培养试验,并在实验室扩大培养中取得成功,1989—1990两年应用于生产性养虾池的试验研究均取得明显的效果。本文就海洋光合细菌的分离、培养试验报告如下:     

光合细菌在我市水产养殖业推广应用

一、国内外光合细菌技术研究及应用动态 自60年代以来,日本的小林正太围绕光合细菌基础理论在环保农畜水产应用做了进一步研究,近年来各国竞相进行研究开发成商品并进入大田性运用成为现实,我国许多水产研究中心、高校应用研究表明,光合细菌具有营养价值高、净化水质能力强、能增强动物抗病能力三大功能,在水产业生产中应用有广阔前景。 二、我市水产业开展光合细菌推广应用工作的必要性 我所以前仅从资料中认识光合细菌研究工作,1990年起与台湾技术员合作中得知这种进口产品可以     

淡水光合细菌分离培养技术

光合细菌(Photosynthetic bacteria,简称PSB)是一类具有光合色素,能在厌氧光照条件下进行光合作用的原核生物的总称。光合细菌的自然生境为有阳光可供利用的水田、沼泽、河川、海洋、土壤、鱼塘等地。近几年有报道应用于水产养殖有促进鱼虾生长,净化鱼虾塘的水质及防治鱼病等作用。我们从1989年开始对这类光合细菌进行了分离、培养,并在实验室扩大培养中取得成功,且     

光合细菌及其在水产养殖业的应用（一）

光合细菌（Photsynthetic Becteria简称PSB）是一类能进行光合作用的原核生物的总称。光合细菌在自然界的分布极为广泛,是地球上物质和能量循环中不可缺少的一大类群微生物。因其细胞内具有细菌叶绿素和类胡萝卜素,常使用光合细菌自下而上的水体或固体呈现出红色。     

微生态制剂在对虾养殖中的使用方法

1微生态制剂的功能(1)光合细菌光合细菌(PSB)是一大类能进行光合作用的原核生物的总称。光合细菌放在虾塘中,能迅速消除水体中的氨氮、硫化氢、有机酸等有害物质,改善水体质量,平衡酸碱度。但对于进入水体中的大量大分子有机物质,例如虾的排泄物、残存饲料、浮游生物残体却无法     

益生菌在凡纳滨对虾育苗中的应用

实验研究了在凡纳滨对虾育苗中添加益生菌(芽孢杆菌、光合细菌或芽孢杆菌 光合细菌)对水体中pH值、H2S、COD、NH 4N、NO-2N和幼体成活率的影响。结果表明:光合细菌对提高水体的pH值有一定作用,而芽孢杆菌对pH值无显著影响;益生菌能显著降低水体中的H2S、NH 4N和NO-2N含量,其中光合细菌去除H2S和NO-2N的效果略优于芽孢杆菌,而芽孢杆菌去除NH 4N的能力比光合细菌强;实验中COD均在较适宜范围,益生菌对COD无显著影响。5mg·L-1芽孢杆菌和1mg·L-1芽孢杆菌 10mg·L-1光合细菌能显著提高育苗成活率。在实验中,1mg·L-1芽孢杆菌 10mg·L-1光合细菌的综合效果最佳,芽孢杆菌和光合细菌具有协同作用。     

光合细菌的培养及其在水产养殖中的应用

光合细菌简称PSB，是一群能在厌氧光照或好氧黑暗条件下利用有机物作供氧体兼碳源，进行不放氧光合作用的细菌，广泛分布于水田、湖语、江河、海洋、活性污泥和土壤中。近年来，光合细菌应用于水产养殖业并取得显著效果。我所自1994年开始光会细菌的培养与应用研究，在对虾和中华鳖养殖、对虾和泥蜡人工有革中试用，均取得较好的效果。本文根据我们的研究实践，综合国内外有关文献，概述光合细菌的培养技术及其在水产养殖中的应用状况。1光合细菌的培养1．1菌种菌种可从采集的池塘底泥中重复富集、分离纯化获得。如用保存下来的菌种，在培…     

光合细菌及其应用

光合细菌(Photo Syntnetie bacteria)广泛分布于湖泊、河流、水田、海洋、土壤之中。它在地球上水的自然净化过程中,有着十分重要的作用。光合细菌分为产氧光合细菌(蓝细菌即蓝藻)和不产氧光合细菌两大类。本文所述主要指后者。此类光合细菌只能在厌氧光照条件下进行光合作用且不产生氧气。对光合细菌的应用研究,日本开展较早,如光合细菌对高浓度有机废水的处理可大幅度降低其中的BOD、COD,现已在不同类型的有机废水处理中推广应用;光合细菌在水产养殖中的利用研究成果已获得专利,已进行了光合细菌的商品性生产。     

用于水产养殖的有益菌类

1光合细菌 光合细菌简称PSB。是国内最早用于水产养殖的细菌制剂。光合细菌是一些能利用光能进行不产氧的光合作用的细菌,革兰氏阴性,无毒,大多数为厌氧菌,细胞内有细菌叶绿素,可在日光下,在无氧条件下以H2S、硫代硫酸根作供氢体,进行不产氧的光合作用,植物的光合作用不同,将两种反应过程比较如下：     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.