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马氏沼虾是我国从斯里兰卡新引进的淡水虾类，外观略呈纺锤形，虾体共分为20节，除尾节外，虾体的每一节各具l对附肢，雌虾和雄虾在第五步足基部分别具有“A”和“M”状突起。头胸甲的胃区、心区、触角区表面较粗糙，两侧还有数条与虾体平行的浅棕色斑纹。虾苗时期多数个体呈淡褐色，性成熟后体色呈浅褐、淡青偏褐色或淡灰色。额角尖端微微上翘向前伸展，但不超出第二触角的触角片末端，上翘高度不超过额角上缘鸡冠状隆起的顶端，齿式为7～13／4～6。其生物学特性与罗氏沼虾和日本沼虾相比有许多相似之处，但在体色、额角、头胸甲和腹甲侧片等形态特征上差异十分明显。本文描述了马氏沼虾的外部形态及结构，比较了上述几种虾的主要特征，并就“雄虾特化”现象以第二步足与体长之比作为依据提出了质疑。 相似文献
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长毛对虾(Fenneropenaeus penicillatus Alcock)又名大虾、白虾、红尾虾、红虾、大明虾,隶属对虾科对虾属,是对虾类中的大型虾之一,广泛分布在印度洋、西太平洋的巴基斯坦到印度尼西亚沿海一带,我国福建、台湾及广东东部沿海最为常见,是南方省区重要的海洋捕捞和养殖对象；养殖120～150天,体长可达120mm 以上,每667m~2产量100kg 左右。 1 形态特征长毛对虾体淡棕黄色,额角上缘7～8齿,下缘4～ 6齿,额角基部侧视比中国对虾的高,而比墨吉对虾的低,额角后脊伸至头胸甲后缘附近,无中央沟,第1触角鞭比头胸甲稍长,雄虾第3颚足末节有毛笔状长毛,其长度为末第2节的1.2～2.7倍,额角脊上有断续的凹点, 雌交接器前片顶端的疣突比墨吉对虾的小。 2 生态习性长毛对虾存活的最高温度为40%,最低10℃C,生长 相似文献
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刀额新对虾（Metapenaeus ensis De haan）俗称沙虾、基嘲虾、虎虾等，形态特征：体色褐绿色，有黑色微圆小点，触鞭血红色，长度是体长的1．6倍，额角后脊达头胸甲的后缘：双侧眼窝后具双刺脊,额角上缘6～9齿，下缘无齿，肝沟“C”宇形，壳较中国对虾稍厚；雌性交接器之中央板长条形，两侧板为脊状硬板，后连两片三角形的后板：雄性交接器腹面观只见三角形的中央突起，侧突出被中央突起所盖，不明显。 相似文献
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眼斑猛虾蛄幼体的发育 总被引：4，自引：0，他引：4
通过对眼斑猛虾蛄（Harpiosquilla annandalei）幼体各发育期的连续取样，在显微镜或解剖镜下系统地观察各发育期的形态变化及生长特征并描图。眼斑猛虾蛄假蚤状幼体经11次蜕皮，在水温24～27℃，盐度25．4～29．0的条件下，历时49d，发育变态成仔虾蛄；第Ⅰ期假蚤状幼体（Z1）体长1．75～1．83mm，头部有一长额角，头胸甲形状似龟壳，有1对腹侧齿，四角有刺，后部中间有一较长棘刺；第Ⅵ期头胸甲形状渐变成梯形，腹侧齿5对，第一触角中鞭萌芽，第二触角内肢发育呈短芽状，第Ⅷ期头胸甲左右两侧边缘开始渐向下弯卷；第Ⅺ期（Z11）体长15．10～17．20mm，第二触角内肢发育成鞭状且分为14～16节，尾肢外肢2节，内肢1节；Ⅰ期仔虾蛄体长14．50～16．10mm，长额角消失，头胸头形状仍为梯形，但光滑无腹侧齿，前侧角圆形，后侧角有二个缺角，这是该种的特征，后部中间棘刺消失，头胸甲占体长的比例明显缩小，形似成体虾蛄。眼斑猛虾蛄的幼体与黑斑口虾蛄的幼体的形态存在一定差异，主要表现在头胸甲与体长的比例，头胸甲的长宽比及第二触鳞片刚毛数和尾节的侧小齿、中间小齿和亚中间小齿的齿数。 相似文献
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为研究三叶唇鱼(Cheilinus trilobatus)消化系统组织特征,采用组织切片技术,对三叶唇鱼消化系统进行组织学观察。结果发现：三叶唇鱼消化道由口咽腔、食道、小肠和直肠构成。口咽腔内颌齿和咽齿发达,颌齿单行排列,1对上咽齿呈三角形左右对称分布,下咽齿由颗粒状齿愈合而成,呈“T”型;肠道短粗,在体腔内形成一个弯曲,呈“之”型排列,比肠长0.32±0.11;消化腺由肝胰脏和胆囊构成,肝脏分成3片,中间大、两边小,包裹在小肠上,胰脏沿肝血管呈弥散状分布在肝脏组织内部,胆囊呈椭圆型,位于肝腹叶下部,肝总管在小肠前部紧挨食道后与小肠连通,比肝胰脏重(1.43±0.32)%。口咽腔壁光滑,粘膜层主要由复层扁平细胞组成,表层有少量杯状细胞,中间有圆形粘液细胞,表层分布有味蕾。食道由粘膜层、粘膜下层、肌层和浆膜层组成,粘膜层由二级和三级指状突起构成,基部有“凹”型类似外分泌腺的结构;肌层特别发达,由外环肌和内纵肌组成,纵肌层呈不连续束状分布,外包一层浆膜,与粘膜下层分界不明显,两肌层间可见肌间神经丛分布。小肠和直肠均由粘膜层、粘膜下层、肌层和浆膜层组成,粘膜层多为一级和二级指状突起,由单层柱... 相似文献
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甲壳动物十足目的大多数种类,其受精卵自产出后就附着于亲体腹部,并完成胚胎发育过程直至孵化,这对于胚胎的发育、保护和幼体散布有重要的生物学意义。胚胎的附着机制较为复杂,与刚毛、卵柄、卵索、卵膜和黏液腺有关:卵柄和卵索的形成决定了胚胎发育的顺利进行;卵膜的变化影响着胚胎的附着;黏液腺在胚胎附着过程中形成卵柄和外层卵膜,胚胎是依靠卵柄或卵索附着于腹肢的刚毛上,进而完成胚胎发育过程。本研究采用常规组织学和扫描电镜的方法研究了罗氏沼虾(Macrobrachium rosenbergii)胚胎及其附着结构。结果表明,胚胎附着与母体腹肢的结构、黏液腺分泌的黏液相关,也与胚胎表面结构、次级卵膜的形态和结构密切相关。原肢底节和内肢刚毛密而长,基部有细小的分支,有利于胚胎的附着,外肢刚毛羽状则有利于胚胎的托附和保护。抱卵雌虾腹肢的原肢和内肢上布满腹肢黏液腺分泌的黏液;携卵刚毛中空、壁厚,刚毛外壁由微绒毛状结构组成,扩大了携卵刚毛的表面积,以利胚胎附着。胚胎外表面由初级卵膜和次级卵膜组成,次级卵膜主要由卵巢黏液腺分泌的黏液参与形成。排卵时,受精卵依靠坚韧的次级卵膜相互粘连,同时,部分受精卵在刚毛上滑动、旋转,并借助次级卵膜逐渐形成了卵柄或卵索固着在腹肢刚毛上。从受精卵到胚胎孵化,胚胎之间最主要的连接方式是依靠次级卵膜的连接。胚胎的表面有许多褶皱和黏液,利于胚胎的附着以及胚胎对溶氧和小分子物质等的通透。以上结构与附着相适应,保证了胚胎发育的顺利进行和幼体的正常孵化。本研究旨为进一步认识甲壳动物胚胎附着机制、胚胎发育和人工育苗的研究提供参考。[中国水产科学,2007,14(1):67-73] 相似文献
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采用电镜对长江口纹缟虾虎鱼成熟精子、卵子及受精早期精子入卵过程进行了观察。结果显示:纹缟虾虎鱼成熟精子由头部和尾部两部分组成。头部呈圆形或近圆形,无顶体,细胞核长径为1.15±0.28μm,短径为0.97±0.22μm,尾部鞭毛长为8.17±1.12μm。核膜外具有双层质膜,质膜表面不平整,在核膜和双层质膜中间有较大空隙存在。中心粒复合体位于植入窝内。袖套两侧分布有2～3个较大的线粒体。鞭毛为典型的"9+2"结构,有侧鳍。成熟卵呈圆形,卵膜表面多沟和嵴,具单一受精孔,孔洞区外径约5μm,孔内壁呈螺旋嵴。在卵的植物极有一盘状突起,突起的中间为圆形,周边有呈网状结构的粘丝与卵壳膜连接。纹缟虾虎鱼精子入卵速度较快,受精过程较短,受精后10～18 s完成精子入卵过程。 相似文献
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扫描电镜观察发现,鸭绿沙塘鳢(Odontobutis yaluensis)卵壳膜由卵柄和卵体两部分构成.卵柄基部为丝状纤维围成的直径200μm、高12.5μm的"圆盘状"结构,使卵子黏附在附着物上.卵柄基部正中有一直径为20 μm的凹陷受精孔.卵柄丝为圆柱体.未受精卵子的系丝表面光滑,呈发散状向外扩散.随着胚胎发育,受精卵的系丝逐步拉长,直径变小,脆性增加.卵壳主要分为两层:内层具有卵膜孔,肌节出现后内膜孔直径为0.2～0.5μm,眼点出现后达到0.9～1.22μm,破膜前期为0.4μm,平均每100μm2有卵孔38个;卵膜外层规则地排布有直径为0.30～0.63μm的孔径.文中讨论了卵壳膜和受精孔的结构与受精卵孵化生态环境的统一. 相似文献
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Psenicka M Rodina M Flajshans M Kaspar V Linhart O 《Fish physiology and biochemistry》2009,35(4):591-597
Spermatozoa of common carp Cyprinus carpio are typically consist of a primitive head without acrosome, a midpiece with several mitochondria, a centriolar complex (proximal
and distal centriole), and one flagellum. During an evaluation of the motility of common carp spermatozoa, we found spermatozoa
with more than one flagellum and/or “double head” in three different individuals. This may be related to abnormal spermatogenesis.
Ultrastructure and physiological parameters of spermatozoa were examined using light microscopy (dark field with stroboscopic
illumination), transmission and scanning electron microscopy, and flow cytometry. The recorded pictures and videos were evaluated
using Olympus MicroImage software. All spermatozoa with more than one flagellum had a larger head and shorter flagella. They
occasionally demonstrated several cytoplasmic channels separating the flagella from the midpiece. Each flagellum was based
upon its own centriolar complex, with the connection of the flagellum to the head always at a constant angle. The flagella
always consisted of nine peripheral pairs and one central doublet of microtubules. Sperm exhibited a relative DNA content
similar to that found in sperm from normal males, with higher coefficients of variation. Although similar abnormalities have
been found in livestock, where they were described as a defect in spermiogenesis, no comparable results have been reported
in fish. The frequency at which these abnormalities occurs, the fertilization ability of males with defects in spermiogenesis,
the influence of these abnormalities on progeny in terms of ploidy level, and the occurrence of deformities warrant further
investigation. 相似文献
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When, in the 1980s, I became interested in the spermatology of fish under the light microscope, active spermatozoa were only visible thanks to their head presenting a sort of “tremor.” This situation was quite frustrating given the lack of possible information regarding the motor part called flagellum. We decided to apply simple technologies, including photography. Due to the high speed of the moving fish flagellum, the microscope illumination used a pulsed light strobe combined with a dark field microscope to record the flagellum image despite its small diameter (< 0.5 μm). Then came high-speed cinematographic microscopy up to 200 fps, as well as video cameras. At the end of the 1990s, an automatic moving object video tracking system began to be commercialized (CASA) with main advantages such as (a) a large number of cells tracked, which greatly improves statistics, (b) computer assistance allowing an automatic analysis that provides many motility parameters. Nevertheless, CASA systems are still unable to provide information about fish sperm flagella that move fast. During the 1990s, analog video camera technologies allowed acquisition of flagellum images with high resolution for detailed analysis. Since the 2000s, the use of high-speed video cameras allows the acquisition of images at a much higher resolution and frequency, up to 10,000 frames per second. Since it became possible to visualize the flagella in motion, a noble function was added to that of a propeller: that of a rudder with what a spermatozoon responds to specific signals delivered by the egg for its guidance. In the future, one can wish that an automatic flagella movement analyzer will become functional. This brief anthology puts forward the large amount of progress accomplished during past 40-year period about spermatozoa movement analysis, especially in fish.
相似文献13.
中华锯齿米虾内外性征分化时间与特征 总被引：1，自引：0，他引：1
通过对中华锯齿米虾(Neocaridina denticulate sinensis)早期性腺发育的组织学观察和第一腹肢的形态学观察,研究了其雌雄性腺分化的时间、分化过程中生殖细胞及第一腹肢变化的特征。实验结果表明,卵原细胞出现在孵化后发育12～18 d的幼体,此时期所有幼体的第一腹肢内肢均具有刚毛。孵化后发育18～22 d幼体的性腺出现了两种类型:类型1和类型2,类型1具有典型的卵巢特征,之后沿着卵巢发育方向分化;类型2兼备精巢和卵巢的一些特征,之后沿着精巢发育方向分化。精巢的分化要经过一个类卵巢的阶段,在该时期还出现了雄性生殖肢,其第一腹肢内肢刚毛数量减少且为卵圆形,而雌性第一腹肢的内肢在形状与刚毛数量上无明显变化,雄性生殖肢的出现与精巢的分化时间是一致的。 相似文献
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The disadvantages of hand counting hatchery produced juveniles of Macrobrachium rosenbergii have been overcome by development of a high speed opto-electronic counter. The hydraulic, mechanical and electronic designs of the Type B counter are described. The counter, extremely fast in principle, is being used and tested under commercial hatchery conditions. Its practical speed of operation and accuracy are expected to exceed 100 000 juveniles per hour and 95%, respectively.About 80% of juveniles show some morphological damage but most of this probably originates in the hatchery rearing tanks. Tests show that slight additional damage is caused only to the antennules of juveniles passing through the counter but this does not affect their subsequent growth rate and survival. It is suggested that density dependent aggression in hatchery tanks is the principal cause of damage. Counter B is shown to be suitable and safe for counting freshwater prawn juveniles. This counter could be adapted to count other macroscopic aquatic organisms via suitable dimensional scaling. No other counters of this type and purpose appear to exist. 相似文献
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In this investigation trichomonads were isolated from the oral cavity in 21 of 110 examined cats, and only from those which were simultaneously FeLV, FIV or FIP positive. By means of scanning electron microscopy the trichomonads were shown to be round or piriform parasites which were on average 7.9 microns long and 6.2 microns wide at maximum width. They had 4 anterior flagella, which were on average 9.4 microns long, an undulating membrane measuring 6.7 microns with no trailing flagellum as well as an axostyle extending on average 5.0 microns beyond the body, and therefore should be attributed to the genus Trichomonas. 相似文献
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Postlarvae or juveniles of Macrobrachium rosenbergii produced in Mauritius are sold at unit price to prawn farmers and are counted individually by hand. This process is time consuming, labour intensive, subject to error and may stress the juveniles; safe rapid electronic counting would be highly advantageous.The design of the hydraulic component of a successful counter prototype, Type A, is described. The counter has 10 parallel channels through which juveniles are carried in a water current. The detection of juveniles passing through these channels can be done photo-electrically. The counter accepts juveniles up to 15 mm in length (eye orbit to tip telson) and has the significant advantage that it can be constructed using only simple hand tools.Survival and growth rate tests, and microscopic examination for damage to appendages of juveniles were done on machine counted and hand counted juveniles. There was no reduction of growth or survival caused by passage through the counter by comparison with the hand counting method, and it is concluded that the counter is not detrimental to juvenile prawns.About 70% of all juveniles tested showed highly variable amounts of damage. The great majority of this damage appears to originate in the hatchery tanks, prior to the experimental treatments. Only in the case of antennules could the use of the counter be shown to increase damage significantly, i.e. from 25% to 38%, but this has no detectable effect on subsequent survival or growth.This appears to be the first counter made specifically for counting macroscopic crustacean juveniles, and via suitable scaling, adaptation to counting other species of crustaceans, fish larvae, etc., should be possible. 相似文献
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采用HE和AB—PAS染色方法分别从组织学和组织化学方面对黄斑篮子鱼（Siganus oramin）消化道进行了研究。结果显示,黄斑篮子鱼口小,口咽腔不宽阔。上颌具细长、尖锐齿,下颌齿短,排列紧密。犁骨、腭骨和舌上无齿。鳃耙齿分叉,食道细长,胃部稍膨大,“V”型,幽门盲囊5～6条,肠长比为2．73。胃腺发达,为管状腺体,开口于胃小凹。幽门部粘膜褶高度降低,褶皱上开始出现类似肠绒毛结构。前肠均分布有许多长条形粘膜褶,空泡状杯状细胞丰富。依据AB—PAS的染色结果将该鱼}肖化道的粘液细胞分为4种类型：I型呈红色,Ⅱ型呈蓝色,Ⅲ型呈紫红色,Ⅳ型呈蓝紫色。食道以Ⅱ型和Ⅲ型为主,胃、肠道和幽门盲囊主要以Ⅱ型和Ⅳ型为主,后肠中Ⅱ型〉III型〉IV型,其中中肠和后肠Ⅱ型占总粘液细胞的比率最大。 相似文献
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Morphological investigations on the changes in flagellar beating was carried out on native (taken from the milt) and thawed sperm of the Siberian sturgeon Acipenser baerii (Brandt). Immediately after activation, the pattern of flagellar wave formation and distribution was the same in native and thawed sperm but, after 27–42 s, depending on the samples, the thawed flagella showed asymmetric and poorly developed waves. The swimming trajectories recorded during 1‐s exposure were much shorter in thawed than in native sperm after 26–28 s motility. In native sperm, the flagella remained in the same axis as the head during the entire motility course, while the head of thawed sperm showed a right angle after 47 s. It is concluded that the freezing/thawing procedure induces some alteration in the dynamics of flagellar beating in many sperm, but these sperm still show progressive displacement. Therefore, the change in morphology of the flagellum during motion is a parameter that should be taken into account in the evaluation of the impact of various treatments on sperm motility. 相似文献