绢丝丽蚌胚胎发育的研究

绢丝丽蚌卵为均黄卵,爱精卵在雌蚌外鳃中进行胚胎发育,其卵裂为不等完全卵裂。在秋季自然常湿（水温变幅为２４－８℃）时,胚胎发育历时５１ｄ,经过卵裂期、原肠期,发育为具有透明原壳、过钩、闭壳肌丝、内足丝、刚毛和外足丝的成熟钩介幼虫。胚胎发育的不同时期与外鳃特征具相关性。     

背瘤丽蚌胚胎发育的初步研究

用显微技术研究了背瘤丽蚌(Lamprotula leai)胚胎发育和钩介幼虫结构。结果表明,背瘤丽蚌卵为均黄卵,受精卵分布在雌蚌内、外鳃腔中进行胚胎发育;胚胎发育同步;胚胎发育过程包括受精卵、卵裂期、囊胚期、原肠期、膜内钩介幼虫期和钩介幼虫期;卵裂为螺旋不等完全卵裂;未受精的成熟卵在鳃腔内退化;胚胎发育期与胚胎、外鳃和内鳃颜色相关;怀卵母蚌胚胎在外界环境变化时容易全部流产。分析认为背瘤丽蚌胚胎发育期的繁殖特征可指导人工苗种生产。     

低旋巴蜗牛胚胎发育的初步研究

对低旋巴蜗牛（ Ｂｒａｄｙｂａｅｎａ ｂｒｅｖｉｓｐｉｒａ） 的胚胎发育过程进行了研究。在２３—２５ ℃气温下, 从卵产出到孵化需３６４ 小时, 直径可增长２０ 倍。胚胎发育全过程可分为７ 个时期： 卵裂期、囊胚期、原肠期、担轮幼虫期、面盘幼虫期、幼螺形成期和孵化期。对各期的外部特征进行了描述, 并绘制了各发育时期的形态特征图。     

扁平圆扁螺(Hippeutis complanatus)早期发育的形态观察

在水温18℃左右条件下培养扁平圆扁螺(Hippeutis complanatus),使其产卵,在光镜下观察其早期发育过程,详细描述各发育阶段的形态特征.扁平圆扁螺胚胎发育属典型的包囊幼虫发育类型,其过程共分为6个时期,即卵裂期、囊胚期、原肠期、担轮幼虫期、面盘幼虫期和仔螺形成期.胚胎于面盘幼虫晚期孵化,在水中完成仔螺形成过程,腹足从三角变为长楔形,幼虫肾退化,螺壳平伏形成仔螺.     

多肠目薄背涡虫的胚胎发育

薄背涡虫(Notoplana humilis)的产卵高峰期在春末夏初。胚胎发育为螺旋式卵裂、外包法形成原肠胚,以大卵裂球储存卵黄。14~16℃下约20d左右幼虫由卵膜中孵化,但不是典型的牟勒氏幼虫。幼虫经历一周左右的浮游生活和两周左右的底栖生活后,逐渐发育为涡虫幼体。     

施氏獭蛤融合卯裂及其胚胎发育过程观察

对施氏獭蛤胚胎发育过程进行了观察,结果显示:(1)与其他双壳类相似,施氏獭蛤胚胎发育过程可以分为卵裂期、囊胚期、原肠期、担轮幼虫期和面盘幼虫期;(2)在卵裂阶段,施氏獭蛤的卵裂方式完全不同于其他动物;施氏獭蛤卵子发育到第一次成熟分裂前期(胚泡破裂前)即有受精能力,但卵子受精后未观察到极体排出的现象,而是有多核受精卵产生;在以后的卵裂过程中,受精卵没有进行其他动物的经裂或纬裂,而是以一种独特的、复杂的分裂方式--融合卵裂进行卵裂,即:二细胞、叫细胞、八细胞进行下一次卵裂之前,细胞核逐渐消失,分裂球逐渐融合成一个细胞,一段时间后在细胞中央逐渐出现数量加倍的细胞核,细胞核逐渐向外周移动,最后一次性地分裂出数量加倍的分裂球.     

扁玉螺早期发育的实验观察

在实验室条件下人工孵化扁玉螺(Neverita didyma)的卵块,观察了其胚胎发育和幼虫发育过程.扁玉螺的早期发育属间接发生型,其胚胎发育包括卵裂期、囊胚期、原肠胚、膜内担轮幼虫、膜内面盘幼虫;幼虫发育包括面盘幼虫、后期面盘幼虫和匍匐幼虫;匍匐幼虫经变态后发育为稚螺.在水温25～26℃条件下,受精卵发育至膜内面盘幼虫约需38h,5～6d后面盘幼虫冲破卵膜而孵化.扁玉螺面盘幼虫的显著特点是具有1对眼点和1对平衡囊,面盘呈双叶状;后期面盘幼虫的面盘为4叶,呈蝴蝶状,足发达,幼虫既能浮游,又能爬行.后期面盘幼虫进一步生长发育,逐渐转入匍匐生活.     

池蝶蚌胚胎发育与繁殖季节性腺的观察

以池蝶蚌(Hyriopsis schlegeli)育儿囊中单细胞胚胎为材料,通过连续观察、人工体外培养等方法,对繁殖季节池蝶蚌的生殖腺特性、生殖细胞形态、胚胎发育过程等进行了观察.结果表明,年满4冬龄池蝶蚌卵巢的相对怀卵量为(2.25±1.09)×103粒/g,绝对怀卵量为1.93×104～1.03 × 105粒;性腺指数为24.09%±0.33%;在体外用自制培养液培养的胚胎,部分能正常分裂发育至桑椹期,其胚胎发育过程经历了4个时期,即卵裂期、囊胚期、原肠期、钩介幼虫期.在18～23℃的水温下,胚胎发育历时约12 d;胚胎发育的最适水温为20～30℃.此外,通过池蝶蚌外鳃的特征可初步判断胚胎发育的时期.研究结果可为池蝶蚌人工繁殖、新品种培育及种质资源保护等提供理论依据.     

婆罗囊螺早期发育的初步研究

描述了婆罗囊螺(Retusa borneensis)从受精卵到幼虫孵化后的发育过程,婆罗囊螺为雌雄同体的一年生贝类,在浙江沿海繁殖期是6∽9月,盛期在7∽8月。婆罗囊螺为体内受精种类,胚胎发育过程为变态发育,可以分为卵裂、囊胚、原肠胚、担轮幼虫和面盘幼虫等几个阶段。个体发育从受精卵的卵裂开始,卵裂为螺旋形的全裂。卵裂不断进行,囊胚形成,后以外包和内陷方式共同形成了原肠胚。婆罗囊螺的面盘幼虫在膜内就已经形成,并且具备运动能力,但是其面盘和纤毛远没有膜外面盘幼虫发达。幼虫浮游一段时间后,就营匍匐生活,然后变态发育为稚贝。本文还就婆罗囊螺的繁殖期、繁殖力、交配产卵和繁殖特性等做了进一步的讨论。     

家蚕胚胎发育过程的组织形态显微观察

胚胎发育是动物许多重要器官与性状发育的重要时期。本文利用石蜡切片法,对家蚕的胚胎发育进行了观察,并在显微镜可见光明场下拍照记录胚胎发育的形态特殊时期及其经历的发育时间,直观地获得家蚕胚胎发育完整过程。实验完整记录了家蚕胚胎发育的5个胚胎发育时期及其相对应:卵裂与胚盘形成期、胚带形成期、器官形成期和完成期及其相对应的发育时间。为进一步研究家蚕个体发育,器官的形成与分化奠定基础。     

东北七鳃鳗早期发育研究

通过开展东北七鳃鳗(Lampetra morii)胚胎、卵黄囊期仔鱼和幼鱼发育研究, 系统地描述东北七鳃鳗的早期发育形态特征和生长发育规律。研究结果表明: 东北七鳃鳗的卵裂为全裂类型, 在(18±1)℃水温下, 受精卵经卵裂期、囊胚期、原肠胚期、神经胚期、头凸期、孵出前期以及孵出期, 历时11—12d孵育出仔鱼。初孵仔鱼体重为(0.00032±0.00002) g, 全长为(0.29±0.02) cm。在卵黄囊期内, 仔鱼体重和全长随日龄的增加而增长, 吻长、眼径、眼鳃间距、口笠长、鳃前长、鳃长、头长、体长、尾长和泄殖孔长均存在异速生长现象。初孵仔鱼经过约15d(卵黄囊期)发育成幼鱼, 幼鱼卵黄囊完全吸收, 消化道贯通, 形成肠道, 开始摄食。在幼鱼期, 经5 个月的培育, 幼鱼体重和全长随月龄的增加而增长, 体色逐渐加深, 5月龄幼鱼的体重和全长分别为(0.07±0.01) g和(3.87±0.32) cm。东北七鳃鳗的早期发育研究为七鳃鳗发育生物学积累基础资料, 同时也为七鳃鳗的人工增养殖提供了科学依据, 推进七鳃鳗的模式化进程。     

Larval case and water balance in Tinea pellionella

In a very dry environment (0% r.h.) the case plays an important role in the physiology of the Tinea pellionella larva. Absence of the case leads to a reduction of oxygen consumption and a great loss of body water. At 0% r.h. the rate of water loss from a larva without its case, is twice that from a larva remaining within its case.In a very humid environment (r.h. higher than 95%) the case absorbs a very large quantity of water and becomes very heavy, but it does not interfere with larval physiology. With or without their cases the weight of the larvae stays stable, and their oxygen consumption does not change.When the humidity changes abruptly, the case acts as a buffer and assists in the regulation of the water balance of the larva. If the humidity decreases the case slows the rate of body water loss; if the humidity increases, it very quickly builds up a reserve of atmospheric water around the larva's body.     

Factors influencing the developmental capacity of Galleria larval epidermis

The nature of the cuticle secreted by integument from a day-1 penultimate instar larval Galleria when cultured in vivo in the abdomen of a last instar larva varied with the age of the host. When placed in a day-5 last instar larva, the implanted integument secreted a pupal cuticle at the time the host metamorphosed and became a pupa. However, when placed in a day-7 last instar larva the implant, from the same stage donor, secreted a larval cuticle at the time the host pupated. Experimental studies involving implantation of the integument for a 24 hr period, into various developmental stages of normal and ligated last instar larvae, pupae, and pharate adults, prior to placing it in a day-7 last instar larva suggest that a non-hormonal factor present in day-4 and -5 last instar larvae is important to initiate pupal syntheses.     

Susceptibility of early larval stages of Pseudaletia unipuncta and Spodoptera exigua (Lepidoptera: Noctuidae) to the entomogenous nematode Steinernema feltiae (Rhabditida: Steinernematidae)

Early stages (neonate to 7- or 8-day-old larvae) of Spodoptera exigua and Pseudaletia unipuncta were exposed to the entomogenous nematode, Steinernema feltiae, at concentrations of 0, 10, 25, 60, 100, or 200 nematodes per larva. Larvae of both species were susceptible to nematode infections. However, neonate larvae of S. exigua were significantly less susceptible to nematode infection than 3- or 8-day-old larvae at or above 50 nematodes per larva. Mortalities of neonate larvae exposed to 50 or more nematodes ranged from 68 to 74% while mortalities of 3- and 8-day-old larvae ranged from 91 to 100%. The results with P. unipuncta showed similar trends as described for S. exigua, albeit at a lower mortality level and usually with no statistical differences. Mortalities of neonate larvae exposed to 50 or more nematodes ranged from 34 to 44% while mortalities of 7-day-old larvae ranged from 32 to 91%.     

Recovery of Bacillus thuringiensis and other bacteria from larvae of Spodoptera littoralis previously fed B. thuringiensis-treated leaves

Exposure of a spore-crystal suspension of Bacillus thuringiensis to UV irradiation for (200 lx) 8.5 min killed most of the spores ($\text{P}\text{P}{}_0\text{= 2.6 × 10}{}^{\mathrm{?4}}$), while the insecticidal activity of the suspension to larvae of Spodoptera littoralis was only slightly affected. Numbers of colony-forming units (CFU) of B. thuringiensis recovered from larvae after ingestion of spores decreased with time as long as the larvae lived and several hours after larval death. Only 3–6 hr after larval death, the spores germinated and multiplied, reaching up to 100-fold after 24 hr. When UV-irradiated suspensions were used, numbers of CFU per larva were too scarce to be recovered from living larvae. However, 1.5 × 10⁶ CFU/larva were recovered 24 hr after death. It seems that the disruption of the gut epithelium by the endotoxin caused a change in the unfavorable conditions for endospore germination, thus providing the suitable ambient for germination and multiplication of B. thuringiensis. Numbers of other bacteria present per milligram of healthy larva increased with larval weight, predominantly Streptococcus sp. and Erwinia sp. In dead larvae, the increase of Erwinia sp. was higher than that of Streptococcus sp. Other bacterial species isolated were: Corynebacterium sp., Micrococcus sp., Serratia marcescens, and Bacillus sp.     

The Establishment of Embryonic Axial Properties in the Nemertean,Cerebratulus lacteus

Experiments were performed to determine whether the first cleavage division plays a role in setting up the dorsoventral axis in embryos of the equal-cleaving nemerteanCerebratulus lacteus.Fertilized eggs were compressed to change the orientation of the first cleavage spindle, and thus the plane of the first cleavage division. One cell of the resulting two-celled embryos was then injected with lineage tracer to determine whether the first cleavage plane always maintains its normal relationships to the median and frontal planes or whether new relationships (and thus, novel cell lineages) could be created. Many of these compressed embryos gave rise to normal-appearing pilidium larvae in which the first cleavage plane had taken on various oblique angular relationships relative to the plane of bilateral symmetry and the dorsoventral axis of the larva. These findings indicate that the first cleavage plane can be dissociated from its normal relationships to these axial properties. Thus, the first cleavage division is not causally involved in the establishment of the dorsoventral and bilateral axes. We argue that the dorsoventral axis is specified prior to the first cleavage division.     

贝氏高原鳅消化系统胚后发育的形态及组织结构

应用解剖学、组织学和组织化学方法,对贝氏高原鳅(Triplophysa bleekeri)消化系统的胚后发育进行观察.结果表明,贝氏高原鳅仔、稚鱼呈线性生长趋势.仔鱼出膜后1～2d为内源性营养阶段,3d进入混合营养阶段,15 d进入外源性营养阶段.初孵仔鱼口凹已经出现,出膜后3d与外界相通,9d口咽腔基本发育完成.8d食道发育基本完成.初孵仔鱼消化道雏形已现,但胃肠未明显分化.出膜后64 d胃小凹处出现胃腺,胃消化功能基本完备.初孵仔鱼肠道已经分化,出膜后27 d肠基本发育完成.初孵仔鱼具有肝前体,出膜后2d肝细胞开始分化,7d肝中出现明显的中央静脉和肝细胞索,肝组织结构与成体差异不大.3d肝前端出现胰组织,4d具有胰雏形,5d完整胰出现,胰腺细胞之间具有大量嗜曙红酶原颗粒物质;9d胰岛出现,胰组织基本发育完成.64 d消化系统各部分组织结构发育基本完成.贝氏高原鳅消化道的形态发育需要很长的时间,出膜后64 d胃肠仅前端膨大,无任何弯曲;85 d胃与食道呈直角弯曲后下行,但胃肠无明显分界;120 d胃弯曲为“Z”形后笔直下行,胃肠仍无明显分界,肝为一整体,未见分叶.1龄幼鱼,消化系统解剖结构与成鱼相似,但肝缺少右叶,肠缺少胃背面的圆环形弯曲.贝氏高原鳅消化系统的胚后发育特点和仔鱼的营养方式可能体现了长江以南地区冬天繁殖鱼类消化系统胚后发育的一般规律和仔鱼的营养趋势.     

The first stage larva of brugia pahangi in Aedes togoi: An ultrastructural study

Lehane M. J. 1978. The first stage larva of Brugi pahangi in Aedes togoi: an ultrastructural study. International Journal for Parasitology8: 207–218. The ultrastructure of the first stage larva in the mosquito is described up to the onset of the first cuticular moult. The following structural changes from the microfilarial stage have been noted at this time; the numbers of muscle cells have increased, usually to four with a maximum of six in each intercordai quadrant ; part of the pharyngeal thread has formed into a knot ; the intestinal lumen has developed and is surrounded in any given transverse section by up to four intestinal cells and the inner body has largely been lost; the anal apparatus has enlarged and developed; the excretory apparatus has largely degenerated. The functional morphology of the various organ systems described is discussed.     

Cleavage and gastrulation in the shrimp Penaeus (Litopenaeus) vannamei (Malacostraca, Decapoda, Dendrobranchiata)

While most malacostracan crustaceans develop through superficial cleavage, in the Amphipoda, Euphausiacea, and Dendrobranchiata (Decapoda) cleavage is complete. Euphausiaceans and dendrobranchiate shrimp share a similar early cleavage pattern, early cleavage arrest and ingression of mesendoderm progenitor cells, a ring of crown cells (prospective naupliar mesoderm) around the blastopore, and hatching as a nauplius larva. Yet recent phylogenies do not support a close relationship between Euphausiacea and Decapoda. In addition, some variation is reported in the timing of mesendoderm cell arrest and number of crown cells for a number of dendrobranchiates. To determine the representative pattern of development in the Dendrobranchiata, embryos of the Pacific white shrimp Penaeus (Litopenaeus) vannamei were stained with Sytox Green to label chromosomes and nuclei and examined with confocal microscopy. The early cleavage pattern, mesendoblast arrest and subsequent ingression at the 32-cell stage, presence of 8 initial crown cells, and fates of the mesendoblasts are the same for P. vannamei (family Peneaeidae) and Sicyonia ingentis (family Sicyoniidae). The lineage of the primordial endoderm cells differs from that reported for P. kerathurus. These characters were discussed in the context of the evolution of development in the Dendrobranchiata and in comparison to the Euphausiacea.     

Tentacle structure and feeding processes in life stages of the commercial sea cucumber Parastichopus californicus (Stimpson)

Tentacle structure and function in the pentacula larva, juvenile, and adult life stages of Parastichopus californiens (Stimpson) were examined via light and electron microscopy. Food particle adherance to the tentacle surface is mediated by an adhesive material in the case of the pentacula larva and additionally by mechanical entrapment in juvenile and adult animals. Mechanical entrapment is of secondary importance to adhesion during feeding.