皱纹盘鲍食道的结构与功能

以组织学，组织化学，扫描电镜和透射电镜观察及酶活性测定等方法研究了皱纹盘鲍的食道，食道可分为前，中后，三段，中段又可分为食物通道和食道侧囊，食道粘膜上皮由纤毛柱状细胞，粘液细胞，闰状腺细胞，微绒毛细胞和分泌细胞组成，纤毛柱状细胞参与运输食物和分泌物，并呈现吸收细胞的结构特征；粘液细胞分泌中性和酸性粘多糖；颗粒状腺细胞内充盈分泌颗粒；微绒毛细胞呈现吸收细胞的特征；分泌细胞具有强的蛋白酶等酶活性，能以楔浆分泌形式分泌消化酶，该细胞还具有吸收和细胞内消化作用。食道中段还呈现3种植物多糖酶活性。     

缢蛏消化盲囊的组织学与组织化学

运用光镜、透射电镜及组织化学方法研究了缢蛏消化盲囊的结构与功能。消化盲囊为复管泡状腺，以导管与胃腔相通。腺上皮由胚性细胞(E-细胞)、纤维细胞(F-细胞)、吸收细胞(R-细胞)和分泌细胞(B-细胞)组成，它们在分布位置、结构及功能等方面各有其特点：E-细胞主要存在于近端(与导管相连处)，体积较小、核质比大，能分化为其它类型的腺细胞；F-细胞内含发达的粗面内质网和游离核糖体，功能是合成、分泌消化酶；R-细胞以脂肪滴和糖原粒的形式储存丰富的能量；B-细胞只见于远端，游离端具发达的微绒毛，内含大量的次级溶酶体和消化残体，有很强的吸收和细胞内消化功能；B-细胞和R-细胞消化脂类的能力较强。导管壁由单层短柱状纤毛细胞和丰富的粘液细胞构成，纤毛柱状细胞能合成、分泌消化酶。消化盲囊参与无机盐代谢。     

单环刺螠虫消化道组织学和细胞学

对单环刺螠虫(Urechis unicoinctus VonDrasche)消化道的结构进行了组织学和细胞学观察。单环刺螠虫消化道可分为咽、食道、嗉囊、砂囊、胃、中肠、呼吸肠、直肠和排泄腔。咽、食道和直肠管壁由内向外分为粘膜层、粘膜下层、肌层和外膜，嗉囊、砂囊、胃、中肠和呼吸肠壁仅由粘膜层和外膜组成。除食道外，胃之前的消化道及直肠上皮细胞均有发达的纤毛，中肠和呼吸肠上皮主要为微绒毛。消化道上皮主要分为3类细胞，第1种为柱状上皮细胞；第2种为粘液细胞；第3种为分泌细胞。粘液细胞和分泌细胞散布于柱状上皮细胞之间，且结构和数量随部位而异：粘液细胞在咽、食道、嗦囊、胃、中肠和直肠上皮中有较多的分布，分泌细胞在砂囊、胃、中肠和呼吸肠中数量较多。     

大黄鱼消化道器官显微与亚显微结构

采用电镜和光镜技术研究大黄鱼消化道的组织结构。大黄鱼舌粘膜上皮为复层扁平上皮，其中含有杯状细胞和味蕾，舌腹面固有膜有浆液性腺泡；食道粘膜上皮为复层扁平上皮，表层扁平细胞下有粘液细胞。胃粘膜上皮为单层柱状，细胞游离端含有大量成熟粘液原颗粒，核周有不同成熟阶段的粘原颗粒，细胞器位于核周及下方，贲门和盲囊部胃小凹处有粘液腺，固有膜含大量胃腺，幽门部没有胃腺；胃腺细胞为矮锥形，细胞内含微管泡系和酶原颗粒，是一种典型的泌酸胃酶细胞。前肠、中肠和后肠粘膜上皮均为单层柱状上皮，其中有许多杯状细胞，肠上皮有密集的微绒毛，侧面有连接复合体，胞内各种细胞器均较丰富。大黄鱼消化道组织结构的特点与消化、吸收作用密切相关。     

幼龄皱纹盘鲍消化道粘膜上皮的超微结构与组织化学

以透射电镜与组织学方法研究 4 5日龄皱纹盘鲍 (Haliotisdiscushannai,壳长 2 .3 0～ 2 .4 0mm ,壳宽1.80～ 2 .10mm)的消化道。结果表明 :①食道分为前、中、后 3段 ;中段分为食物通道和食道侧囊 ,食道侧囊的分泌细胞含大量的囊泡和分泌颗粒 ,呈强的蛋白酶和非特异性酯酶活性 ;食道前段、食物通道及食道后段粘膜上皮由纤毛细胞和粘液细胞组成。②嗉囔粘膜上皮只有 1种细胞 ,细胞游离缘具有长达 4 .0 μm的密集微绒毛。③胃粘膜上皮由纤毛细胞和微绒毛细胞组成。④肠和直肠粘膜上皮由 5种细胞组成 ,即纤毛细胞、微绒毛细胞、分泌细胞、颗粒状腺细胞和粘液细胞 ,分泌细胞基部有少量的分泌颗粒。⑤存在于消化道各部位的微绒毛细胞游离缘均具密集的微绒毛 ,游离端质膜呈碱性磷酸酶活性 ;食道和肠的粘液细胞分泌粘多糖 ;食道、胃和肠的纤毛细胞游离缘具纤毛。     

条石鲷消化道的形态学和组织学

采用解剖和光镜技术研究条石鲷消化道的形态学和组织学。条石鲷消化道包括具有发达颌齿的口咽腔，食道，胃，小肠和直肠。食道上皮组织可分为两个区域－头部和尾部，头部区域由扁平上皮层构成，尾部区域的上皮组织由单层柱状上皮细胞所构成，上皮含有大量 杯状细胞和黏液分泌细胞.胃呈V形，其粘膜上皮由单层柱状上皮组成，贲门部和胃体部上皮下有发达的胃腺组织。小肠上皮为具微绒毛的单层柱状上皮，肠道粘膜固有层中有管状肠腺存在；直肠上皮为单层柱状上皮，缺乏粘膜肌。小肠和直肠上皮中均分布有较多的杯状细胞，肠道系数约为0.78。在整个消化道中发现有四种杯状细胞。本文研究了条石鲷消化道的显微结构，并探讨了其消化道的组织学和解剖学特征与其杂食性的适应。     

长竹蛏消化系统的组织学和组织化学研究

用组织学和组织化学方法对长竹蛏的消化系统进行了研究。长竹蛏消化腺腺管上皮有消化细胞和嗜碱性细胞两种类型。消化细胞内含许多颗粒,具有酸性磷酸酶活性,表明该细胞能进行细胞内消化。消化腺导管柱状细胞亦呈现酸性磷权酶活性,并具有密集的微棋毛。消化道膜上皮由纤毛柱状细胞和少量的粘液细胞组成。食道有分泌中性和酸性混合粘液物质的上皮下粘液细胞。胃和肠上皮具帽白酶和非特异性酯酶活性。肠上皮还个酸性磷酸酶和碱性磷酸     

栉孔扇贝和太平洋牡蛎的唇瓣结构

运用石蜡切片和扫描电镜技术研究了栉孔扇贝和太平洋牡蛎的唇瓣结构。结果表明，2种贝的唇瓣结构都是中间一层结缔组织，两侧被覆纤毛柱状上皮，结缔组织中富含血腔隙。栉孔扇贝唇瓣的粘膜上皮由柱状细胞和杯状细胞组成；而太平洋牡蛎由柱状细胞、杯状细胞和嗜酸性粒分泌细胞组成。扫描电镜下，2种贝唇瓣的褶皱面呈现沟和嵴，纤毛浓密；光滑面纤毛较少。太平洋牡蛎唇瓣褶皱面的游离边缘部分和光滑面有大量的球状突起，这是杯状细胞所在处。纤毛和粘液在食物分栋和运输中起重要作用。     

褐菖鲉消化道的组织学和组织化学

褐菖鲉消化道的组织学和组织化学=Study on histology and histochemistry of digestive tract in Sebastiscus marmoratus[刊,中]/石戈（浙江海洋学院海洋科学学院,浙江 舟山 316004）,王健鑫,刘雪珠,王日昕//水产学报.－2007,31（03）.－293～302 利用光镜技术对褐菖鲉消化道进行了组织学和组织化学研究。组织学研究表明：褐菖鲉消化道由口咽腔、食道、胃和肠4部分组成。口咽腔较大,上下颌,犁骨及腭骨均有细齿带,粘膜由复层鳞状上皮组成,并含有大量黏液细胞和少量杯状细胞;食道粗而短,上皮组织包括扁平上皮层区域和单层柱状上皮层区域,上皮含有大量杯状细胞和黏液分泌细胞,粘膜层的固有膜中含有腺体;胃呈Y型,包括贲门、胃体和幽门3个区域,胃粘膜由单层柱状上皮组成,在贲门和胃体部的粘膜层中有厚的结实层,上皮有大量的胃小凹和胃腺组织;胃幽门部括约肌明显,幽门上皮不含胃小凹;胃与肠相接处有8～9个指状幽门盲囊,其形态学和组织学特征与前肠类似;肠道上皮由单层柱状上皮细胞组成,丰富的微绒毛形成明显的纹状缘,上皮中含有大量杯状细胞,肠道系数为0.54。组织化学研究显示：幽门、幽门盲囊和肠上皮细胞顶端胞质和纹状缘具碱性磷酸酶活性;幽门盲囊及肠道上皮细胞顶端胞质中检测到酸性磷酸酶活性;在贲门部和胃体部的固有层以及幽门上皮还检测到酯酶活性,且酯酶定位于幽门柱状上皮细胞胞质的上半部。整个消化道的粘膜层中存在许多粘液细胞：食道上皮含大量酸性粘液细胞,胃上皮细胞均含有中性粘液,而肠道由前向后中性粘液物质逐渐减少,酸性粘液物质逐渐增多。组织学和组织化学的结果表明褐菖鲉食道有润滑和微弱的消化作用,胃有消化脂类和吸收糖类的功能;幽门和盲囊有较强的吸收脂类的功能;前肠、中肠和后肠有活跃的细胞内消化和吸收功能,整个消化道结构与其肉食性功能密切相关。图3参29     

长鳍篮子鱼消化道显微与超微结构观察

采用光镜和电镜技术观察了长鳍篮子鱼消化道的组织结构。结果表明,食道黏膜上皮为复层扁平上皮,表层扁平细胞下有黏液细胞,黏膜下层含有大量腺体。胃黏膜上皮为单层柱状,胃贲门、盲囊部分布有许多腺体,幽门部较少;胃柱状细胞中有较多的线粒体、粗面内质网和高尔基体,在一些细胞中含有大量的吞饮泡。肠道黏膜上皮为单层柱状上皮,其中含有许多杯状细胞;肠上皮细胞游离面有密集的微绒毛,侧面有连接复合体,胞内细胞器较丰富,在细胞上部分布有大量多泡体。由前肠到后肠,黏膜褶皱高度由高变低,数量逐渐减少,肌层逐渐变厚,后肠分布有大量淋巴细胞,紧密排列成环状。幽门盲囊组织构造与肠道相似,但上皮细胞游离面有比肠道更密集的微绒毛。长鳍篮子鱼消化道组织结构的特点与其消化、吸收作用密切相关。     

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.