急性低温胁迫对四指马鲅幼鱼肝脏、肌肉以及鳃组织结构的影响

为探究急性低温胁迫对四指马鲅Eleutheronema tetradactylum 幼鱼肝脏、肌肉以及鳃组织结构的影响。该研 究设置了常温(27±0.5 ℃)组、20 ℃组以及15 ℃组共三个温度梯度进行试验, 以常温组作为对照,在试验进行的2 h、6 h 以及12 h 分别采集肝脏、肌肉以及鳃样品进行观察和测定。结果显示: 随着低温处理时间的延长, 20℃组的肝脏细胞空泡结构呈增多, 细胞核偏离, 染色变浅趋势; 肌纤维出现弯曲现象, 肌纤维之间与内部均出现较大间隙; 线粒体丰富细胞数目增多, 鳃小片末端轻微的膨大到鳃小片整体水肿且严重弯曲, 血管以及血窦内出现大量的红细胞, 部分鳃小片因红细胞过多而涨破; 同时, 15 ℃组肝脏细胞排列混乱, 肝板结构不清晰, 细胞核溶解, 肝脏整体失去固有形态。肌纤维间隙增大, 部分断裂直至肌纤维之间与内部均严重开裂, 部分肌纤维溶解并暴露出细胞核。鳃小片表皮出现轻微的脱落, 少部分鳃小片胀大到其吸水涨破, 鳃小片基本形态不可见。该研究结果为优化四指马鲅养殖生产温控管理措施, 提高越冬成活率提供参考资料。     

塑料袋包装充氧运输胁迫对四指马鲅幼鱼抗氧化系统的影响及抗应激剂的作用

为探究塑料袋包装充氧运输胁迫对四指马鲅(Eleutheronema tetradactylum)幼鱼肝、肌肉抗氧化系统的影响以及抗应激剂的生理作用。本研究设置了未经运输的幼鱼30尾作为对照组、不添加任何抗应激剂运输的幼鱼90尾作为空白组、添加维生素C(VC)运输的幼鱼90尾作为维生素C组以及添加谷氨酰胺(Gln)运输的幼鱼90尾作为谷氨酰胺组,在运输实验进行的2 h、6 h以及9 h采样,不同时间点每组各取30尾幼鱼分别采集肝、肌肉样品进行相关指标的测定。测定项目包括:超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)、丙二醛(MDA)以及总抗氧化能力(T-AOC)。结果显示,运输胁迫使空白组肝和肌肉中SOD活性最终显著(P0.05)高于对照组,而维生素C组和谷氨酰胺组由于抗应激剂的存在而使其最终活性低于对照组;运输胁迫使空白组和维生素C组肝以及肌肉中CAT活性显著(P0.05)升高,最终其活性均显著(P0.05)高于对照组,而谷氨酰胺组最终值与对照组无显著差异(P0.05);运输胁迫使空白组肝和肌肉MDA含量均显著(P0.05)升高,而抗应激剂维生素C和谷氨酰胺明显缓解了这一现象;GSH含量在空白组、维生素C组和谷氨酰胺组的肝与肌肉中均出现了不同的变化趋势,可能与这两种组织所承担的生理功能不同有关;运输胁迫后,空白组肝与肌肉T-AOC值均显著(P0.05)高于对照组,而维生素C组和谷氨酰胺组最终则略高于或等于对照组。本研究分析了运输胁迫下四指马鲅幼鱼抗氧化系统变化规律以及抗应激的作用效果,旨在为其养殖生产提供参考依据。     

中华鲟视网膜早期发育及趋光行为观察

视觉在鱼类摄食、集群、繁殖及洄游等活动中起着重要的信息传递作用,深入研究鱼类的视觉特性,对阐明其行为机制,了解视觉结构在不同发育时期的生态适应性具有重要意义[1]。鱼类和其他脊椎动物一样,感光细胞由感受强光的视锥细胞和感受弱光的视杆细胞组成。鱼类受到不同光强度照射时,能以不同的方式调节达到光感受细胞的有效光强度,从而适应于光亮或者黑暗的环境。鱼类感知光线刺激后能产生定向性运动,称为趋光反应。渔业生产上的光诱捕鱼根据这种特性用集鱼灯将鱼诱集到预定的水域进行捕捞,可大大提高渔获量。中华鲟(Acipenser sinensisGra…     

细叶马先蒿根系发育形态学研究

细叶马先蒿为玄参科多年生草本植物。年生产周期明显缩短。根系营养生长至花期为粗壮主根与纤细侧根并存,果期侧根几乎全部枯萎脱落,所存留根系皆呈乳白色。由胚根形成的初生主根根毛密集,初生木质部二原型。侧生分生组织只有形成层而无木栓形成层。根表皮细胞经解离后略呈不规则方形片状,横切面为平周长梭形,进行垂周分裂增加梭形根表皮细胞长度,以适应根的增粗生长。根表皮脱落时,外皮层以同样生长方式代替脱落的表皮。在年     

鳜早期味蕾发育的组织学特征

采用石蜡切片、H.E染色研究了3 ~ 28日龄鳜（Siniperca chuatsi）味蕾发育的组织学特征,并通过扫描电镜观察28日龄鳜口咽腔组织味蕾类型与数目。结果表明,未开口期（3日龄）,鳜口裂未张开,味蕾尚未分化;开口期（7日龄）,鳜口裂张开明显,味蕾呈椭圆形,突起高度平缓,主要分布在上下颌上皮上,舌、咽、鳃弓上皮上有少量分布;稚鱼期（14日龄）,味蕾呈圆锥形,突起高度上升,舌和咽上味蕾数目增加;21日龄,味蕾呈近梯形,突起高度不变,下颌、舌、咽上味蕾数增加,鳃弓上味蕾数目显著增加;28日龄,味蕾发育完全,口咽腔味蕾数继续增加。扫描电镜观察表明,鳜味蕾主要有3种类型：Ⅰ型味蕾近球形,含有大量微绒毛,突起高于上皮,味孔向外突起;Ⅱ型味蕾含有少量微绒毛,突起略高于黏膜上皮,味孔向内凹陷;Ⅲ型味蕾微绒毛含量最少,突起几乎与黏膜上皮共面,味孔平坦或凹陷。上下颌、咽、鳃中以Ⅰ型味蕾数量最多,Ⅱ型味蕾最少,舌上主要分布Ⅰ型味蕾,无Ⅲ型味蕾。结果表明,鳜早期味蕾结构发育与其摄食关联,推测其主要通过Ⅰ型味蕾和Ⅱ型味蕾对食物的机械性和化学成分进行识别。     

锯缘青蟹精巢发育的组织学观察

组织学观察表明,锯缘青蟹（Scylla serrata)精巢发育周期可以分为精原细胞期,精母细胞期,精子细胞期,精子期和休止期5个时期。在划分精巢发育期的基础上,结合生精小管直径的成熟节段比例这2个指标,可以较准确地反映锯缘青解精巢的发育状况。而成熟节段比例可以作为锯缘青蟹精巢发育的表征指标。     

猫视网膜多巴胺能神经元的形态和发育

Morphology and development of dopaminergic neurons has been studied in the kitten retina, using tyrosine hydroxylase (TH) immunocytochemistry. TH immunoreactive (TH+) cells are already presented in whole amount and sectioned retina at first postnatal day (P1). According to soma size, shape, dendritic process pattern and immunoreactivity, two classes, type I or large dark staining TH+ cells and type II or small light staining TH+ cells are recognized. The TH I cells which consisting of normal placed DA amacrine cells, displaced DA amacrine cells and DA interplex-form-like cells, gradually mature during postnatal development, while TH II cells decrease quickly and through disappear at P30. After eye opening TH I amacrine cells, especially their dendrites develop quickly. The soma diameters increase from 11.8 microns (P1) to 14.2 microns (P30). The dendritic fields increase in size and complexity. At P1 the thick radiating dendrites emerge from the cell body with small or large "spines" and many growth cones. At P13 the dendritic field is markedly enlarged and only a few growth cones can be seen on some stained dendrites. In addition, the dendritic spines are no longer apparent and they are a part of rudimentary rings. By P30 the dendritic plexus of TH+ dendrites and rings in the out most part of IPL, typical of the adult cells, are complete. The influence of light on the development of DA cells after eye opening and the possibility of neurotransmitter changing are discussed.     

移植视网膜NOS阳性神经元的发育

目的 观察不同年龄组段大鼠正常视网膜及移植视网膜内NOS阳性神经元的发育情况及其定位分布。方法 实验分正常视网膜发育组和移植视网膜发育组,应用还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）组织化学方法显示。结果 1、NOS阳性神经元最早出现于生后第五天（P5）,P18时阳性神经元数目达到最高峰,2、移植视网膜具有正常视网膜的各层结构和相似的生长规律,NOS阳性神经元在生后第4天移植视网膜（TP4）中出现,TP12数量达到高峰值,TP22后降至正常成年鼠水平。结论 根据NOS阳性神经元的定位,分布,推测其为无长突细胞,移位无长突细胞及节细胞。     

根田鼠视网膜的胚后发育

视觉对动物的生活习性尤其是取食具有重要意义。本文对根田鼠视网膜的胚后发育进行了研究,结果表明:出生3d内根田鼠视网膜分化程度较低,神经节母细胞层尚未分化,占据了视网膜层的一半以上;5日龄时,外网层开始出现;6日龄时,外网层开始清晰,外核层与内核层更加清晰;18日龄时,视网膜结构与成年根田鼠结构相似,各层结构清晰可见。测量了神经节细胞层和外核层的细胞密度以及核层厚度,结果表明:随着个体发育,外核层细胞层厚度及细胞密度不断增加;而神经节细胞层厚度及细胞密度不断减少。与褐家鼠、黑线姬鼠、大仓鼠、棕色田鼠、甘肃鼢鼠、达乌尔黄鼠、岩松鼠视网膜相比,根田鼠视网膜结构介于夜行性与昼行性鼠类之间[动物学报52(2):376-382,2006]。     

Histological profiling of gonads depicting protandrous hermaphroditism in Eleutheronema tetradactylum

The fourfinger threadfin Eleutheronema tetradactylum is reported as a protandrous hermaphrodite from Australian waters, while being a gonochorist in reports from Singapore and India, with a single report of protandrous hermaphroditism from the latter. Histological analysis of gonads of fish from Indian waters confirms protandrous hermaphroditism in E. tetradactylum. The study was based on 480 fish examined from eight locations along the Indian coast. Mean total length (L_T) of male fish was 240 mm with the transition to female starting from 280 mm L_T. Specimens confirmed as mature females were >380 mm L_T.     

红腹锦鸡和丽纹龙蜥视网膜的组织学观察

为了进一步探讨动物视网膜结构与机能的关系,利用光镜和扫描电镜比较观察了红腹锦鸡(Chrysolophus pictus)、丽纹龙蜥(Jspalura splendida)视网膜的结构。结果表明,红腹锦鸡、丽纹龙蜥的视网膜均由四层细胞构成,在光镜下均可分为十层结构。红腹锦鸡视网膜平均厚225·2μm,视细胞与节细胞数比约为2:1;丽纹龙蜥视网膜平均厚156.2μm,视细胞与节细胞数比为1:1。红腹锦鸡、丽纹龙蜥视网膜视细胞的平均密度分别为(124828±24404)个/mm2和(33165±7034)个/mm2。显示了红腹锦鸡和丽纹龙蜥均具有昼行性动物视网膜的结构特征。     

Revision of the Indo-West Pacific polynemid fish genus <Emphasis Type="Italic">Eleutheronema</Emphasis> (Teleostei: Perciformes)

A taxonomic revision of the polynemid fish genus Eleutheronema, which is redefined, resulted in three species of the genus being regarded as valid: Eleutheronema rhadinum (Jordan and Evermann, 1902), having to date been treated as a junior synonym of E. tetradactylum (Shaw, 1804) and currently known only from East Asia (China and Japan) where it is endemic; E. tetradactylum, a senior synonym of both Polynemus teria Hamilton, 1822 and Polynemus coecus Macleay, 1878, being a widely distributed Indo-West Pacific species, which ranges from the Persian Gulf to Australia; and E. tridactylum (Bleeker, 1845), distributed in Southeast Asia (Thailand, Malaysia, and Indonesia). Eleutheronema tridactylum is easily distinguished from both E. rhadinum and E. tetradactylum owing to the vomer lacking tooth plates in the former [vs. vomer with 2 deciduous tooth plates (in specimens at least over ca. 70 mm SL) in the latter] and lower counts of pectoral filaments (free lower rays, 3 vs. 4) and gill rakers [mode 8 (range 4–10) vs. 12 (10–17) and 13 (6–18) in E. rhadinum and E. tetradactylum, respectively]. Eleutheronema rhadinum clearly differs from E. tetradactylum in having higher counts of pored lateral line scales [mode 95 (range 82–95) vs. 73 (71–80) in the latter] and higher scale counts above and below the lateral line [12 (11–14) and 16 (15–17), respectively, vs. 10 (9–12) and 14 (13–15), respectively]. Furthermore, E. rhadinum is distinguished from E. tetradactylum by having a dense black pectoral fin [vs. vivid yellow in life (except in specimens over ca. 350 mm SL, pectoral fin dusky-yellow) in the latter]. Intraspecific variations and morphological changes with growth of the three species are also discussed. Received: June 13, 2001 / Revised: October 11, 2001 / Accepted: October 17, 2001     

Biochemical Aspects of Chick Embryo Retina Development: The Effects of Glucocorticoids

In chick embryo retina during development, DNA synthesis and the activities of DNA polymerase, thymidine kinase, thymidylate synthetase, and ornithine decarboxylase (ODC) declined in parallel from day 7 to 12. The administration in ovo of hydrocortisone reduced significantly, particularly at 8-10 days of incubation, both DNA synthesis and the four enzyme activities tested. The effect was dose dependent, reaching the maximum with 50-100 nmol of hydrocortisone, 8-16 h after treatment. The highest inhibition was found for ODC activity (70%), followed by thymidine kinase activity (62%) and DNA synthesis (45%), whereas activities of DNA polymerase and thymidylate synthetase were reduced only by 30%. The inhibitory effect was exerted by all the glucocorticoids tested, with dexamethasone and hydrocortisone being the most efficacious. The results support the view that glucocorticoids reduce the proliferative events in chick embryo retina, particularly at 8-10 days of embryonic life.     

哲罗鱼消化系统器官发生发育的组织学观察

采用形态观察与连续组织切片技术,对哲罗鱼(Hucho taimen)胚胎期(水温7~8℃)和胚后期(水温3~14℃)消化系统的发生发育进行观察和研究。结果表明,哲罗鱼受精11d形成原始的消化管。受精18d肝原基出现,U型胃雏型形成。受精30d鱼体破膜,口能自由闭合。破膜8d后,齿形成,肛门与外界相通,消化道初步形成口咽腔、食道、U型胃、肠和肛门。破膜16d,胰及瓣囊出现,仔鱼消化系统初步具备了摄食和消化外源性食物的能力。破膜24d后,鱼体开始上浮,主动摄食,由内源性营养转向混合性营养。破膜30d后,卵黄囊完全被吸收,各消化器官功能和结构逐步发育完善,鱼体由混合性营养进入外源性营养阶段。此后随着鱼体的生长消化器官逐步发育成熟,舌齿和下颌齿分别为双排,胃腺发达,形成网状结构,幽门盲囊较多,肠为直行,肝和胰为相互分开的独立器官。     

中华鳖眼睛发育的形态及组织学观察

在孵化基质沙粒径为0.3～0.6mm、孵化温度为(33.0±0.5)℃、孵化基质的湿度为7%～10%、相对湿度为70%～85%的条件下孵化中华鳖(Trionyx sinensis)卵,孵化周期35～36 d.破壳取不同发育时期的胚胎并制作切片,观察眼睛发育的形态学和组织学特征.孵化第4 d头部两侧出现眼泡的突起;第6d眼睛开始出现色素,第14 d色素由褐色变为黑色;第7 d瞳孔出现,透过瞳孔可见晶状体;虹膜于第14d出现,第18、19 d瞳孔周围呈放射状;巩膜突自第19 d出现,第21 d增至最多,第23 d消失;上、下眼睑分别在第19 d和22 d出现,第32 d眼睑可覆盖瞳孔,眼睛形态与成体眼睛相似.表皮外胚层于第3 d形成角膜原基和晶体泡,第32 d角膜发育完成;第34 d晶状体发育完成;神经外胚层于44～48 h由前脑的两侧分化形成视泡,第3 d由视泡分化形成视杯,并逐步分化形成视网膜;第23 d视网膜的八层结构基本形成;第34 d视网膜发育完成.     

Acetylcholine and Dopamine Promote the Production of Platelet Activating Factor in Immature Cells of Chick Embryonic Retina

We have previously shown that platelet-activating factor (PAF), a naturally occurring lipid mediator of cell-to-cell communication, was produced by 3-day-old chick retina stimulated with acetylcholine (ACh) and dopamine (DA), but not with other neurotransmitters. ACh and DA stimulated PAF synthesis via a dithiothreitol (DTT)-insensitive cholinephosphotransferase, without affecting the acetyltransferase pathway, which was stimulated only by the calcium ionophore A23187. Therefore, we attempted to study the effects of neurotransmitters on PAF production and on the activities of the DTT-insensitive cholinephosphotransferase and acetyltransferase in the developing chick embryo retina up to hatching. Our results show that PAF was produced already at 8 days of development, when retinal cells are still rather immature and ganglion and Mueller cells are the only differentiated cells. The stimulation of PAF production occurred with ACh and not with other neurotransmitters. In older stages, DA also stimulated PAF production, as already described in the chick after hatching. DTT-insensitive cholinephosphotransferase and acetyltransferase activities were present in 8-day-old embryos, the earliest stage analyzed. Both enzymatic activities increased with age; DTT-insensitive cholinephosphotransferase increased rapidly from day 12 up to day 18, whereas acetyltransferase activity increased linearly up to the time of hatching. To promote PAF production, ACh and DA activate DTT-insensitive cholinephosphotransferase, but not acetyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Localization of Hexokinase in Neural Tissue: Immunofluorescence Studies on the Developing Cerebellum and Retina of the Rat

Abstract: Antiserum against purified rat brain hexokinase (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1) has been used in a study of the distribution of hexokinase during the postnatal development of rat cerebellum and retina. The cells of the external germinal layer of the cerebellum exhibit little or no fluorescence. The Purkinje cells exhibit a transient increase in hexokinase levels between 2 and 8 days postnatally, followed by a precipitous decrease (8–12 days) to the relatively low levels found in the mature Purkinje cell. Development of the intensely fluorescent cerebellar glomeruli in the granule cell layer is readily followed during the 3rd and 4th weeks postnatally. With respect to postnatal changes in hexokinase distribution of the retina, perhaps most notable is the observation that even the cytoplasmic protrusions which represent the precursors of the photoreceptor segments are richly endowed with hexokinase. Biochemical differentiation of the photoreceptor segments into hexokinase-rich inner segments and hexokinase-poor outer segments is readily observed long before the growth of the photoreceptor segments has been completed.     

Identification of Insulin in Chick Embryo Retina During Development and Its Inhibitory Effect on DNA Synthesis

Incubation of chick embryo retinal explants with insulin resulted in a pronounced inhibition of thymidine uptake and incorporation into trichloroacetic acid-insoluble fraction. The inhibitory effect was highest with explants from embryos at day 7 and day 8, and thereafter it declined markedly with the age of embryos until day 11. A time-course study of the effect revealed that the inhibition occurred after a lag time; both thymidine uptake and incorporation were not altered significantly after 2-6 h of incubation with insulin, but began to decrease thereafter, reaching the maximum after 16 h. The effect was also dose dependent. After 16 h of incubation, the maximal inhibition (65%) was found with 10(-8) M insulin. Insulin caused similar effects also on thymidine kinase activity. All these effects were obtained by using minimal essential medium without glutamine. The addition of glutamine to the medium reduced the inhibitory effect of insulin. Retinas of chick embryos contain immunoreactive insulin. Retinal immunoreactive insulin was at the highest level (1.12 ng/mg of protein) in the youngest retinas studied (day 6), then it declined with age, reaching the lowest value (0.58 ng/mg of protein) at day 14. This value did not vary significantly during the third week of development. A potential biological role of insulin in retinal development is discussed.