固定化微生物修复养殖池塘污染底泥的围隔试验

摘要：通过测定上覆水的多项水质指标、底泥总有机碳(TOC)、底泥生物降解能力(G值)、底泥异养细菌数和反硫化细菌数等指标值,在野外实验围隔条件下比较了固定化微生物和游离微生物（FR-M）对污染底质的生物修复能力。微生物固定所用载体包括：纤维网状活性炭,生物活性炭,沸石和硅藻土(相应的固定化微生物分别标记为FC-M、 BC-M、ZE-M和DI-M组)。结果显示：固定化微生物对围隔内水质有间接影响,试验后期固定化微生物组（ZE-M、DI-M和FC-M组）的上覆水硝氮浓度显著高于对照组;BC-M组和ZE-M组上覆水中的COD值显著低于游离微生物组(FR-M)和对照组,说明固定化微生物有效削减了水底界面还原性物质的污染程度;与游离微生物或对照组相比,固定化微生物组（FC-M组、DI-M 组和ZE-M组）能更有效地降解底泥有机质。固定化微生物对底泥生物降解能力（G值）的影响明显,实验后期固定化微生物组（（BC-M组、DI-M组和ZE-M组）的G值均显著高于对照组和游离微生物组,说明固定化微生物技术的运用显著提高了围隔底泥的生物降解能力;固定化微生物对围隔内底泥异养细菌总数影响不显著,可能是由于底泥微生物群落结构受其它多种因子的综合影响所致。固定化微生物对底泥反硫化细菌影响显著,与对照组和游离微生物组相比,固定化微生物（尤其是ZE-M和BC-M组）能更有效地减少围隔底泥反硫化细菌数。本实验结果显示,利用载体固定微生物技术能显著提高微生物对污染底质的生物修复能力,其中以ZE-M和BC-M组效果最好。     

添加光合细菌对糙海参幼苗培育阶段的影响研究

以受精后24h孵化出的糙海参（Holothuria scabra）耳状幼体为研究对象,探讨养殖水体不同量光合细菌对糙海参苗期生长、成活、消化道消化酶活性和养殖水体水质变化的影响。试验设4个处理,光合细菌（浓度为1×10^11cfu·mL^-1）添加量分别是0m L（组1,对照组）、50m L（组2）、100m L（组3）和150m L（组4）,每个处理设3个重复,每个重复放养4×10^4尾幼体于室内水泥池（5m×3 m×1.5m）中,试验周期为41 d。结果表明,添加光合细菌组的糙海参出苗体质量和成活率均显著高于对照组（P〈0.05）,而组3和组4的体质量和成活率又明显优于组2（P〈0.05）,组3和组4之间的差异不显著（P〉0.05）。添加光合细菌还能不同程度地影响糙海参苗体消化道蛋白酶、淀粉酶和纤维素酶的活性,试验组3种酶的活性均显著高于对照组（P〈0.05）,而组3和组4的蛋白酶活性和纤维素酶活性显著高于组2（P〈0.05）,淀粉酶活性在3个试验组之间无显著差异（P〉0.05）。在试验第10天后,各试验组氨氮（NH3-N）和亚硝酸盐含量显著低于对照组（P〈0.05）,在试验第20天后,各试验组化学需氧量（COD）的值显著低于对照组（P〈0.05）,而总磷（TP）的差异不大（P〉0.05）。表明光合细菌可以促进糙海参幼体的生长,提高消化酶活性和成活率,并改良育苗水体水质。     

固定化光合细菌在中华绒螯蟹人工育苗中的应用

用包埋法制备固定化光合细菌,并通过制备方法及使用方法的改进,使净化水质效果得到改善。四种不同包埋载体的试验结果表明,含３％沸石的海藻酸钙凝胶珠强度最大,净化水质活性最高。水体中ＮＹ３－Ｎ,ＮＯ２－Ｎ的含量及ＣＯＤ值的下降度随包埋比的增大而增大。对固定化光合细菌的用量及活化处理方法进行了探讨。     

固定化光合细菌去除水中氨氮效果的初步研究

光合细菌固定化是一生物新技术，本文报导了利用这一技术去除水体中氨氮的效果，在运输鲤鱼鱼种中比添加游离光合细菌运输成活率提高10．9％；比对照组成活率提高13．9％。氨氮去除率敞口篓（96．44％），优于密封篓（71％）。本文并对固定化光合细菌在生产实际中的应用前景进行了讨论。     

光合细菌在河蟹育苗中的应用试验

１材料与方法１．１光合细菌为中国科技大学研究生院北京奇威生物工程研究所研制开发的“红精灵”牌光合细菌，活菌群数不低于３０亿个／毫升，外观为红色悬浮液。１．２试验场所试验选择在明光市女山湖镇蟹苗场二分场塑料大棚池，育苗池均为水泥结构，面积４０米２，池深１．８米，水质、光照条件好，供水、增氧、供热、排水系统齐全，Ⅰ号池为试验组，Ⅱ号池为对照组，两口池基本条件相似。１．３使用方法试验组（Ⅰ号池）从４月１５日～６月１日，共使用光合细菌５０千克，对照组（Ⅱ号池）不使用。使用方法：（１）浸泡法抱卵亲蟹下池前…     

固定化光合细菌净化养殖水质研究

采用海藻酸钠进行光合细菌固定化试验,比较了固定化菌和悬浮态菌的生长和生理特性,观察了其在载体中的分布,并对其净化养殖水的能力进行了初步研究.结果表明,固定化大大提高了光合细菌的生长速率;粒径为3.5mm,菌初始密度为0.12mg/L为最佳固定化条件.在生长初期,细菌在载体内的分布不均匀,后期趋于一致.固定化光合细菌对养殖水的净化能力大大优于悬浮态菌.     

固定化光合细菌研究与应用

介绍了光合细菌的种类和基本特性,总结了固定光合细菌的材料、方法和固定化光合细菌的活性,以及在养殖水净化、有机废水处理和生物制氢等方面的应用性研究成果。并基于固定化技术可以提高光合细菌的活性和单位体积生物量、在适当条件下固定化光合细菌能够保持优势生长、固定化光合细菌法工艺条件的可控性及其应用效果,揭示了其技术应用的可行性。     

TF血浆蛋白粉在断奶仔猪日粮中的应用对比试验

本试验选用２９日龄（２８天断奶）的杜×长×大断奶仔猪４５头,按体重随机分为３组,每组１５头。试验Ⅰ、Ⅱ组为对照组,Ⅲ组为试验组。试验Ⅰ组只喂基础日粮,Ⅱ、Ⅲ组分别添加６％的ＳＤＰＰ_１（进口血浆蛋白）、ＴＦ血浆蛋白粉,试验结果表明：试验Ⅰ、Ⅱ、Ⅲ组的日增重分别为１７２．５ｇ、２４１．２ｇ和２４２．８ｇ,Ⅰ组与其它２组均差异极显著（Ｐ＜０．０１）;Ⅱ、Ⅲ组之间差异不显著（Ｐ＜０．０５）,从料肉比看,Ⅰ组与其它２组均差异极显著（Ｐ＜０．０１）,Ⅱ、Ⅲ组之间差异不显著（Ｐ＞０．０５）、整个试验期间,仅试验Ⅰ组有４头仔猪发生腹泻,腹泻发生率为２６．７％。经分析,每增重１ｋｇ,添加ＴＦ比添加ＳＤＰＰ_１节省费用１．３４元,效果显著。表明ＴＦ喷干血浆蛋白粉无论在免疫、促长,还是经济效益方面均效果明显,是取代进口的理想产品。     

固定化浓缩光合细菌对氨氮降解作用的研究

用光合细菌、固定化光合细菌、浓缩光合细菌、固定化浓缩光合细菌和芽孢杆菌对养殖用水进行处理，比较各种处理对养殖用水的氨氮降解效果。实验结果表明，浓缩光合细菌和固定化浓缩光合细菌对氨氮的降解作用较好，水体中的氨氮全程控制在0．60mg／L以下，达到了虾类养殖规范的要求。     

复合光合细菌对热带鱼养殖水质净化作用的研究

从高原湖泊滇池和阳宗海中分离到光合细菌,经过挑选后进行复合培养,投放入养殖热带鱼的水族箱。试验结果证明,添加光合细菌后,水族箱水体的COD、氨氮和总磷显著降低,pH略有上升,溶解氧含量提高,水质得到显著净化。     

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.     

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.     

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.