黄鳍鲷和尼罗罗非鱼鳃丝表面结构扫描电镜观察

黄鳍鲷Sarus latus和尼罗罗非鱼Oreochromis nilotica鳃丝和鳃小片表面都具有规则或不规则分布的环形微嵴、沟状或坑状凹陷及孔洞等结构.黄鳍鲷的鳃丝表面一部分鳃丝表皮凹凸不平,另一部分鳃丝表皮较为平坦.黄鳍鲷和尼罗罗非鱼鳃上皮几种细胞的形态结构及数量分布存在细微的差异.黄鳍鲷的扁平上皮细胞表面观以不规则的六边形为主,或类似菱形的四边形,细胞间界限清楚,而尼罗罗非鱼鳃丝细胞表面的微嵴以形成密集指纹状回路,隆起的微嵴两侧有细小的横突,扁平上皮细胞间排列凹凸不平,形成深沟或凹坑,成为细胞间明确的界线.黄鳍鲷鳃丝表面的氯细胞和粘液细胞数量较多,尼罗罗非鱼鳃丝表面基本上没有观察到氯细胞,粘液细胞很少.黄鳍鲷鳃小片的厚度比尼罗罗非鱼鳃小片的厚.     

怒江裂腹鱼鳃的显微和超微结构

通过光镜、扫描电镜及透射电镜技术,研究了怒江裂腹鱼(Schizothorax nukiangensis)鳃的组织结构和超微结构。结果表明,怒江裂腹鱼鳃基本结构与其他硬骨鱼相似,均由鳃耙、鳃弓、鳃丝以及鳃小片构成,且各部分具有不同的组织结构和细胞类型。扁平上皮细胞覆盖于整个鳃表面,其表面的纹路主要有3种类型,在鳃上不同的部位具有不同的结构和功能。线粒体密集细胞主要分布于鳃小片基部,仅有一种细胞类型,顶端膜内凹呈浅滩型,细胞内具有大量圆形的线粒体。怒江裂腹鱼鳃内扁平上皮细胞和线粒体密集细胞的形态结构与其在急流中游泳和摄食活动等生活习性相适应。本研究结果丰富了怒江裂腹鱼的基础生物学资料,并为阐明鱼类鳃的结构特征与其生活习性之间的关系提供参考。     

马氏珠母贝精子的超低温保存

采用光镜和透射电镜方法，研究了不同盐度驯化下施氏鲟幼鱼鳃中泌氯细胞的分布和结构特征。结果显示，在淡水中，施氏鲟幼鱼鳃中的泌氯细胞数量较少，且主要分布在近鳃小片基部，胞体与核均较大而明显，胞内含大量线粒体；泌氯细胞中有网管和囊管，但网管欠发达，囊管分布面积小，细胞表面有顶隐窝。表现为典型的淡水型泌氯细胞（freshwater-type chloride cells）特征。与淡水组相比，盐度10组鳃泌氯细胞的分布和结构变化均不明显，仅数量略有增加，胞体变大。幼鱼在盐度25海水中驯化65d，鳃丝和鳃小片上泌氯细胞数量明显增加，泌氯细胞集中分布在鳃小片基部；超微结构显示，细胞内线粒体数量明显增加，胞质中网管颇为发达，囊管丰富，顶隐窝扩大，表面有微绒毛，表现为α-型（α-subtype）泌氯细胞特征。泌氯细胞具有分泌体内过多Na^＋、Cl-以及调节体液渗透平衡的功能，其数量和结构变化与幼鱼所处的高渗环境相适应。     

盐度对花鲈幼鱼鳃、脾及肌肉组织结构的影响

为了探究不同盐度对花鲈(Lateolabrax maculatus)幼鱼组织结构的影响，用组织学方法对不同盐度条件下(0、10、15、20、30)花鲈幼鱼的鳃、脾及肌肉组织结构进行研究。结果显示，盐度为0时，花鲈幼鱼鳃丝排列紧密，顶端膨大呈棒状，鳃小片细胞饱满，有少量泌氯细胞。花鲈幼鱼鳃丝宽度随盐度的升高而缩小，鳃小片间距则逐渐增大，差异显著(P<0.05)；盐度为20时，部分鳃小片变形脱落，鳃丝上的泌氯细胞明显增多增大；盐度为30时，鳃丝宽度较大，出现断裂脱落，鳃丝上细胞排列疏松，泌氯细胞明显膨大，有溶解现象。脾脏在淡水条件下(盐度为0)，淋巴细胞数目较少，血细胞较多；在低盐环境中(盐度为10、15)，淋巴细胞增大，数量增多，黑色素巨噬细胞中心数量增加；在高盐度下(盐度为30)，脾细胞和部分淋巴细胞出现肿大、空泡化现象，细胞排列疏松。盐度为0时，花鲈幼鱼肌纤维排列较为疏松，多角形或长椭圆形，长径和短径较大、密度较小；盐度为15时，肌纤维短径变小、密度增大，与0、10盐度组均差异显著，盐度为30时，肌纤维长径增大、密度减小；随着盐度的增加，肌纤维长径和短径均有先减小后增加的趋势，单位面积肌纤维数量则先增加后减小，差异显著(P<0.05)。结果表明，花鲈幼鱼鳃、脾及肌肉组织结构变化特征与其所处的环境盐度有关。     

不同盐度和驯养时间中华鲟子二代幼鱼鳃的显微结构变化

采用光学显微镜和组织切片方法,研究了不同盐度和驯养时间中华鲟幼鱼鳃及鳃中泌氯细胞的结构变化特征。试验用鱼为1+龄中华鲟子二代,平均全长50.7 cm,平均体重约441.9 g。试验前在养殖池中暂养1周。试验设2个盐度梯度(10、15)组和1个对照组(淡水)。盐度驯养为将中华鲟子二代从暂养池转入盐度10海水中驯养,分别取驯养1、3、6、9、12、24、48、72、96、120、144、168、192、216、240和264 h的幼鱼各1尾用于试验;将剩下的鱼再转入盐度15海水中驯养,分别取驯养24、48、72 h的幼鱼各1尾用于试验。结果显示,在淡水组中,中华鲟子二代幼鱼鳃丝发达,细胞饱满,鳃小片宽且长。鳃丝上皮的泌氯细胞数量较少,通常靠近鳃小片基部,呈近椭圆状。与淡水组相比,盐度10组的幼鱼鳃丝主干部明显变窄,鳃小片基部区域及鳃小片上泌氯细胞的数量略有增加,胞体变大,且随驯养时间的延长,出现了明显的细胞膜间隙。幼鱼在盐度15组中鳃丝主干明显变窄变短,鳃小片也显著缩短,鳃泌氯细胞数量显著增加,主要分布在鳃小片基部,有明显的分泌腔。中华鲟子二代幼鱼能够快速适应外界水体盐度的变化,这与鳃及鳃上皮中调节渗透压功能细胞的数量和结构变化相适应。     

卵形鲳鲹胚后发育阶段鳃的分化和发育

采用组织学和扫描电镜等方法,鲹研究了卵形鲳(Trachinotus ovatus)胚后发育阶段鳃的分化和发育及其结构和功能的关系。观察发现,仔稚鱼鳃的早期发育可分为3个阶段:第1阶段(0~3日龄)为原基期,鳃原基形成但未分化,鳃耙未出现,仔鱼主要依靠鳍褶、皮肤和卵黄囊上的微血管进行呼吸;第2阶段(4~17日龄)为鳃丝分化、发育期,鳃弓、鳃丝、鳃小片、鳃耙逐渐形成,具备鳃的基本结构和形态特点;第3阶段(18日龄之后)为鳃器官生长发育完善期,鳃弓、鳃丝、鳃小片、鳃耙发育完善,鳃的形态和功能与成鱼相似。进一步研究发现,鳃丝总数随仔稚鱼全长和体质量的增加而增加,单个鳃小片面积和总呼吸面积随仔稚鱼体质量的增加而增大。结果表明,卵形鲳鲳鲹的分化和发育是与仔、稚鱼的生长、形态发育和功能的完善相一致的。     

淡水和半咸水条件下中华鲟幼鱼鳃上皮泌氯细胞的形态特征与数量分布

为了探讨中华鲟幼鱼进入长江口半咸水环境后,渗透压适应调节过程中鳃上皮泌氯细胞的适应性变化,将幼鱼在淡水(盐度0)和半咸水(盐度15)两种条件下驯养60 d,利用光镜和扫描电镜技术对比分析鳃上皮泌氯细胞的形态、分布与数量特征。结果表明:幼鱼鳃上皮泌氯细胞主要集中分布于鳃小片基部和鳃小片之间的鳃丝上,细胞略呈椭圆形。半咸水条件下,幼鱼鳃丝上皮泌氯细胞数量和大小显著增加,鳃小片上皮泌氯细胞数量则未发生改变,但细胞大小显著增加;而鳃丝和鳃小片上皮泌氯细胞的形态在淡水和半咸水中均未发生显著变化。扫描电镜观察发现,鳃丝上皮泌氯细胞顶膜开口的形态分为3种类型:Ⅰ型,突起型;Ⅱ型,凹陷型;Ⅲ型,深洞型。淡水条件下,顶膜开口形态多为Ⅰ型和Ⅱ型,未发现Ⅲ型存在;而半咸水条件下,顶膜开口形态以Ⅲ型为主,Ⅰ型与Ⅱ型也有少量分布。     

人工培育四指马鲅鳃组织结构及其早期发育

采用组织切片和透射电镜技术对人工培育四指马鲅(Eleutheronema tetradactylum)鳃结构及其早期(1—35日龄)发育进行观察。结果显示,鳃耙列齿状,鳃丝梳状排列在鳃弓上,鳃小片排列在鳃丝两边。透射电镜下鳃小片主要由线粒体丰富细胞(Ⅰ型和Ⅱ型)、扁平上皮细胞、柱细胞、血细胞、黏液细胞和未分化细胞组成。四指马鲅鳃早期发育显示,1日龄鳃原基形成;3日龄出现鳃弓,有扁平上皮细胞和血细胞;5日龄出现鳃小片,鳃小片上有柱细胞,基部有线粒体丰富细胞;18日龄鳃小片增多,鳃结构完善;35日龄鳃结构基本和成鱼一致。根据发育特点将其分为3个阶段:第1阶段(0—3日龄)为原基期,鳃原基形成但未分化,仔鱼主要靠鳍褶、皮肤和卵黄囊上的微血管进行呼吸;第2阶段(4—17日龄)为鳃结构分化、发育期,鳃耙、鳃弓、鳃丝、鳃小片逐渐形成,具备鳃基本的结构特点;第3阶段(18—35日龄)为鳃结构完善期,鳃组织发育主要体现在数量和形状的变化。     

苏氏鲢鲶鳃超微结构观察

对苏氏鲢鲶鳃结构进行扫描和透射电镜观察.鲢鲶鳃丝末端膨大呈杓状结构,每一鳃丝两侧具许多呈褶状的鳃小片,相邻两鳃丝上的鳃小片紧密镶嵌排列.鳃弓和鳃耙表面分布众多味蕾.鳃丝呼吸面上皮细胞薄,高度血管化,形成呼吸面隆起;非呼吸面由微脊细胞彼此相连,间缝具分泌细胞开口.鳃小片由单层或数层外上皮细胞和由基膜相隔的柱状细胞及其围在血管腔的凸缘构成,氯细胞多分布在鳃小片基部,并有开口通外.还探讨了鲢鲶鳃丝和鳃小片特殊的结构与功能.     

苏氏Mang鲶鳃超微结构观察

对苏氏Mang鲶鳃结构进行扫描和透射电镜观察。Mang鲶鳃丝末端膨大呈杓状结构，每一鳃丝两侧具有许多呈褶状的鳃小片，相邻两鳃丝上的鳃小片紧密镶嵌排列。鳃弓和鳃耙表面分布众多味蕾。鳃丝呼吸面上皮细胞薄，高度血管化，形成呼吸面隆起，非呼吸面由微脊细胞彼此相连，间缝具分泌细胞开口。鳃小片由单层或数层外上皮细胞和由基膜相隔的柱状细胞及其围在血管腔的凸缘构成，氯细胞多分布在鳃小片基部，并有开口通外，还探讨了Mang鲶鳃丝和鳃小片特殊的结构与功能。     

Environmental preferences of longlining for yellowfin tuna (Thunnus albacares) in the tropical high seas of the Indian Ocean

A survey of yellowfin tuna, Thunnus albacares , fishing ground was carried out on board of the Chinese longliners from September 15 to December 12, 2005 in the tropical high seas of the Indian Ocean. The depth at which each yellowfin tuna was hooked was estimated using a stepwise regression analysis of theoretical hook depth and observed average hook depth measured using a temperature depth recorder. Water temperature, salinity, chlorophyll  a , dissolved oxygen and thermocline, which are important variables influencing yellowfin tuna habitats, were measured in the survey. Catch rates of yellowfin tuna were then analyzed with respect to depth, temperature, salinity, chlorophyll  a , dissolved oxygen and thermocline. We suggest that the optimum ranges of swimming depth, water temperature, chlorophyll  a and dissolved oxygen concentration for yellowfin tuna are 100.0–179.9 m, 15.0–17.9°C, 0.090–0.099  μ g L⁻¹, 2.50–2.99 mg L⁻¹, respectively; that salinity has less influence on the vertical distribution of adult yellowfin tuna; and that yellowfin tuna are mainly distributed within the thermocline in the high seas of the Indian Ocean. Our results match the yellowfin tuna's vulnerability to deep longline fishing gear well.     

Comparison of the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye (T. obesus) tuna associated with drifting FADs in the equatorial central Pacific Ocean

We evaluated the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) associated with drifting fish aggregating devices (FADs) in the equatorial central Pacific Ocean. A total of 30 skipjack [34.5–65.0 cm in fork length (FL)], 43 yellowfin (31.6–93.5 cm FL) and 32 bigeye tuna (33.5–85.5 cm FL) were tagged with coded transmitters and released near two drifting FADs. At one of the two FADs, we successfully monitored the behavior of all three species simultaneously. Several individuals remained around the same FAD for 10 or more days. Occasional excursions from the FAD were observed for all three species, some of which occurred concurrently for multiple individuals. The detection rate was higher during the daytime than the nighttime for all the species, and the detection rate for bigeye tuna was higher than for yellowfin or skipjack tuna. The swimming depth was deeper during the daytime than nighttime for all species. The fish usually remained shallower than 100 m, but occasionally dived to around 150 m or deeper, most often for bigeye and yellowfin tuna during the daytime. The swimming depth for skipjack tuna was shallower than that for bigeye and yellowfin tuna, although the difference was not large, and is probably not sufficient to allow the selective harvest of skipjack and yellowfin tuna by the purse seine fishery. From the detection rate of the signals, bigeye tuna is considered to be more vulnerable to the FAD sets than yellowfin and skipjack tuna.     

急性和慢性低氧胁迫对卵形鲳鲹鳃器官的影响

文章研究了窒息点以上的低氧胁迫对卵形鲳鲹(Trachinotus ovatus)鱼体鳃器官的影响,在常温条件下对(32.84±3.99)g的卵形鲳鲹进行了急性(0 h、3 h、6 h、12 h、24 h)和慢性(14 d)的低氧胁迫实验,采用常规石蜡切片和H-E染色以及电子显微技术,观察低氧胁迫对卵形鲳鲹鳃器官的影响。结果显示,卵形鲳鲹在急性低氧胁迫下鳃小片上皮肿胀和抬升;慢性低氧胁迫下随着时间延长,鳃小片上皮细胞与鳃小片分离,鳃呼吸表面积增加。结果表明低氧胁迫对卵形鲳鲹鳃器官具有较大影响,而且慢性胁迫的影响大于急性胁迫。     

Amyloodinium ocellatum (Brown, 1931) (Dinoflagellida) infestations in cultured marine fish at Eilat, Red Sea: epizootiology and pathology

Abstract. Since 1977, repeated outbreaks of infestation by Amyloodinium ocellatum (Dinoflagellida) in cultured gilthead bream Sparus aurata L. and seabass Dicen-trarchus labrax (L.) resulted in sporadic and mass mortalities. Fingerlings and yearlings as well as breeders were affected and, since 1978, larval and post-larval S. aurata in the hatchery. Infestations in juvenile and breeder fish were located predominantly on the gills and mucosal integument but in larval fish only the skin rather than the gills was infested. Histopathological changes of the infested gills are described. Vacuolar degeneration of the cells penetrated by the parasites' rhizoids was evident at the site of attachment and cloudy swelling was apparent in the surrounding epithelial cells. In heavy infestations the entire epithelium of the gill filaments underwent hyperplasia with consequent fusion of the lamellae. Where hyperplasia was extensive the cells gradually degenerated while the inner epithelial layer showed distinct spongiosis and in some cases completely disintegrated. All heavily infested gills lacked mucous cells.     

Morphological changes in gill mitochondria-rich cells in cultured Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> acclimated to a wide range of environmental salinity

Morphological changes in gill mitochondria-rich (MR) cells were examined in cultured Japanese eel acclimated to deionized freshwater (DFW), freshwater (FW), 30%-diluted seawater (DSW), and seawater (SW). The gill Na⁺/K⁺-ATPase activity was higher in SW-acclimated eel than in those acclimated to DFW, FW, and DSW. Immunocytochemical observations revealed that MR cells in the gill filaments were most developed in SW, whereas MR cells in the lamellae were preferentially observed in DFW, suggesting that filament and lamellar MR cells are responsible for ion secretion and absorption, respectively. In scanning electron microscopic observations, the apical membrane of lamellar MR cells appeared as a flat or slightly projecting disk with a mesh-like structure on its surface. In contrast, the apical membrane of filament MR cells showed a slightly concave surface. Whole-mount immunocytochemistry revealed that most MR cells showed cystic fibrosis transmembrane conductance regulator immunoreaction in their apical region in fish in DSW and SW, but not in those in DFW and FW, indicating that MR cells developed in DSW and SW function as an ion-secreting site. In addition to MR cells, distinct Na⁺/K⁺-ATPase immunoreaction was observed in the outermost layer of gill epithelia, suggesting that pavement cells are an additional site of ion uptake in the gills.     

稀有鮈鲫鳃的组织结构及水体镉暴露对其影响

运用石蜡切片技术和扫描电镜技术对稀有鮈鲫(Gobiocypris rarus)鳃结构进行观察,并采用浓度为2 mg/L的Cd Cl_2水溶液对稀有鮈鲫进行急性毒理实验。结果显示:稀有鮈鲫具4对鳃,由鳃耙、鳃弓、鳃丝及鳃小片组成。鳃的各个部位表面均有上皮细胞覆盖;鳃耙和鳃弓具味蕾,鳃弓上还具不同类型的黏液细胞;相邻鳃小片的上皮细胞间也分布有黏液细胞,在鳃小片基部有氯细胞着生。鳃丝表面有不规则凹陷和微嵴,具沟、坑、孔等结构;鳃小片两面均呈凹凸状。在2 mg/L的Cd Cl_2水溶液暴露下,鳃受到损伤,发生鳃小片充血呈球状,鳃上皮水肿、脱落,黏液细胞增多等现象;并随时间延长受损程度加重。     

漂白粉蓄积对日本昭示(虫寻)4种组织超微结构的影响

根据急性毒性试验确定了漂白粉对日本的安全质量浓度为0.6mg/L,采用透射电镜技术研究了该质量浓度下漂白粉蓄积对日本4种组织细胞(肌肉、鳃、肝胰脏和心脏)超微结构的影响。试验结果表明:漂白粉主要损伤日本的鳃和肝胰脏,其次是心脏,肌肉基本无损害。鳃细胞的损害表现为鳃丝水肿,细胞器溶解,角质层变薄,线粒体、内质网的肿胀、解体;肝胰脏细胞的主要损害特征为肝管微绒毛减少、线粒体水肿解体、内质网扩张、细胞核空泡化、核膜水肿、脂肪滴增加;心脏细胞的毒理变化为线粒体内嵴肿胀、瓦解,肌原纤维不规则,内质网溶解。安全质量浓度的漂白粉经16d蓄积后,虽没有导致日本死亡,但已对其体内的鳃、肝胰脏、心脏等组织细胞的超微结构产生了不同程度的影响。