Structure of the ovary and mode of oogenesis in a freshwater crab Potamon dehaani

Structure of the adult ovary and oogenetic mode were examined in the freshwater crab Potamon dehaani. An H‐shaped ovary consisting of a pair of long ovarian sacs connected by a narrow bridge tube is located in the cephalothorax on the dorsal side of the stomach. A short oviduct with a seminal receptacle is connected with the posterior end of each ovarian sac, and a genital pore opens on the sternum of the sixth thoracic segment. The ovarian wall consists of a layer of ovarian epithelium that infolds to form a number of oogenetic pouches of various sizes. These are present mainly in the anterior regions of the ovarian sacs, are scarce in the posterior regions of the ovarian sacs, and are absent from the bridge tube. Each oogenetic pouch contains an egg or a relative large oocyte in its lumen. Germaria containing oogonia, very early previtellogenic oocytes, and somatic interstitial cells are located in the ovarian epithelium near the necks of the oogenetic pouches in the anterior regions of the ovarian sacs and are randomly scattered throughout the ovarian epithelium in the posterior regions of the ovarian sacs. In cross section, the germaria appear to be concentrated into a central germarial cluster in the ovarian sac. In the posterior regions of the ovarian sacs, however, the germaria are randomly scattered throughout the ovarian epithelium. An early previtellogenic oocyte leaves its germarium and raises the ovarian epithelium infolds to form a new oogenetic pouch in which it grows to maturity. Mature eggs are ovulated from the oogenetic pouches into the ovarian lumen, transferred from the ovarian lumen into the oviducts, fertilized there by sperm stored in the seminal receptacles, and then oviposited through the genital pores. The female reproductive system is surrounded wholly and tightly by a thin, cellular, membranous sheath, which has often been mistaken as the ovarian epithelium in some decapod crustaceans. J. Morphol. 239:107–114, 1999. © 1999 Wiley‐Liss, Inc.     

中华绒螯蟹成熟卵形态和超微结构的研究

中华绒螯蟹的成熟卵仅有初级卵膜，无次级和三级卵巢，质膜初期厚而多层，且具皱褶，卵核在卵的发育过程中变化很大，未发见中心粒，内质网和高尔基体均始见于蟹卵发育的初期，皮层颗粒先出现于蟹卵深部，随后移到卵的表层，无滋养细胞，蟹卵由卵泡细胞提供物质，形成卵黄，此外，还可直接从血淋巴内摄取卵黄前身物质。     

The effect of invertebrate diets on lipids, fatty acid composition and physiological condition of pike larvae (Esox lucius)

The present study tests two invertebrate diets for pike larvae reared in floating cages. One diet contained mainly copepods and cladocerans such as Eucyclops serrulatus and Bosmina longirostris , while the other diet contained Eucyclops serrulatus together with a small proportion of large Chydoridae and chironomid larvae. During the first days of the experiment, the amount of food distributed to the larvae was insufficient (9–17.1 prey per larva and per day) and led to an increase in the mortality. Triacylglycerol contents of fry were low and dietary fatty acids were either catabolised or, concerning PUFA such as 22:6(n-3), incorporated into phospholipids. From day 13 to the end of the study (day 22), the most abundant diets distributed were accompanied by an increase in triacylglycerol PUFA and in triacylglycerol contents of larvae. During the same period weight and length growth were better for larvae reared on the copepod plus Chydoridae and chironomid diet, than for larvae reared on the copepod and Bosmina diet. The use of a lipid condition index based on the triacylglycerol/sterol ratio suggested that Chydoridae and chironomids positively influenced the growth and nutritional condition of larvae. The effects of prey type in terms of PUFA composition on pike larvae are discussed.     

水稻PDER品系的特点和二倍体孢子生殖胚囊的形成和发育

对水稻（ＯｒｙｚａｓａｔｉｖａＬ．）早发生胚ＰＤＥＲ（ｐｒｅ－ｄｅｖｅｌｏｐｅｄｅｍｂｒｙｏｏｆｒｉｃｅ）品系的特点和细胞胚胎学研究表明,ＰＤＥＲ是二倍体植物２ｎ＝２４,约有５０％胚囊的卵细胞未经受精能自行发育形成胚,成熟种子的萌发和生长速度较常规正常水稻快。ＰＤＥＲ的大孢子母细胞经有丝分裂产生未减数的胚囊,即无融合生殖中的二倍体孢子生殖类型。在胚囊形成和发育过程中有如下几个特点：（１）孢原细胞至大孢子母细胞分裂前的过渡期持续时间较长,孢原细胞和大孢子母细胞的细胞质比周围的珠心细胞质稀淡。（２）大孢子母细胞经二次有丝分裂后形成直线排列的三个细胞（三分体）,珠孔端的两个解体,合点端的一个发育为功能细胞,有少数胚囊的三个细胞全部解体形成败育胚囊。（３）功能细胞经三次连续核分裂形成具八核七个细胞的成熟胚囊,它的结构与常规正常水稻基本相同,但助细胞呈长形而没有回抱着卵细胞。     

韭菜幼小子房培养时胚囊的发育和一些异常现象

对韭菜开花前1天左右的子房进行培养可获得大量的单倍体植株。观察表明单倍体植株起源于未受精的卵细胞和反足细胞。为了探索培养不同发育时期的子房对单倍体原胚发生频率的影响,我们又对大孢子母细胞时期的幼     

Egg sac damage and previous egg sac production influence truncated parental investment in the wolf spider,Pardosa milvina

Life history theory predicts that iteroparous animals adaptively partition reproductive effort between current and future reproduction. When rearing costs of current offspring exceed the potential benefits, parental care should be terminated and deferred toward future reproduction. We tested two related predictions that follow from life history theory: (a) parents should be sensitive to offspring viability and withhold parental care if offspring survival probability drops and future reproductive opportunities are likely, and (b) parents should be less sensitive to offspring survival probability when future reproduction is unlikely and maximize parental care late in life. The wolf spider, Pardosa milvina, demonstrates extensive parental care; however, they may also abandon or cannibalize their egg sacs. We tested the effects of egg sac damage and production of a previous egg sac on egg sac abandonment and cannibalism decisions. Among four egg sac groups (1st egg sac intact, 1st egg sac damaged, 2nd egg sac intact, 2nd egg sac damaged), we daily monitored egg sac abandonment and cannibalism and measured differences in egg sac searching, protection, and grooming among removed and damaged egg sacs (N = 116 with 1st egg sac and 88 with 2nd egg sac). Females with first egg sacs abandoned and cannibalized damaged egg sacs significantly more compared to unmanipulated egg sacs; however, females with second egg sacs were insensitive to egg sac damage. Females also spent significantly more time protecting second egg sacs compared to first egg sacs and groomed damaged egg sacs significantly more than undamaged. These results support the general predictions of life history theory that indicate that abandonment and cannibalism should decrease with diminished future reproductive potential and that parents should be less sensitive to indicators of offspring survival probability late in life.     

Inhibitory effects of the androgenic gland on ovarian development in the mud crab Scylla paramamosain

Isolation and characterization of androgenic hormone in decapod crustaceans depend on an effective bioassay of its action. In the present study, the effect of androgenic gland on ovarian development in the mud crab Scylla paramamosain was investigated with a view to develop a bioassay for androgenic hormone. Ovarian regression with degeneration of oocytes occurred in some female crabs implanted with androgenic gland in vivo. In vitro incubation of ovarian tissues at secondary vitellogenesis in extract of androgenic gland resulted in a significant decrease in amino acid uptake by the tissues. We propose that this inhibitory effect could be established as an effective bioassay for the isolation of androgenic hormone in the mud crab.     

Biology of a hoplonemertean from the branchial chambers of the pinnotherid crab Zaops (= Pinnotheres) ostreum

The pea crab, Zaops ostreum, a symbiont in the mantle cavity of the American oyster (Crassostreavirginica), is itself a host to a symbiotic nemertean. Thisnemertean belongs to the genus Carcinonemertes, and issimilar to or possibly the same as C. pinnotheridophila,known from another sympatric pinnotherid crab, Pinnixachaetopterana. Living in mucous sheaths within the gillchambers of female crabs, the life cycle of the nemertean isintimately synchronized with and dependent on the crab's reproduction. A total of 138 pea crabs were collected andexamined for nemerteans during the summers of 1965 to 1967 atBeaufort, North Carolina, U.S.A.; of these 97 (70%) were mature(5th stage) female crabs. Mature females harbored thenemerteans, and had a prevalence of 39.2%. A maximum of 20worms was found in the gill chambers of a single crab, 9 ofwhich were the red, eyeless, mature female worms, along with 11colorless males. Worm egg sacs were attached to the pleopods ofovigorous crabs; a maximum of 293 sacs was recorded in anindividual crab with 7 mature females. At about 110 eggs persac, this translates to a potential production of >32 200nemertean larvae. Since female Z. ostreum may live for 2to 3 yr and produce two broods of eggs per year (beyond thefirst year), the reproductive potential of the symbionts may beeven greater. Gills of crabs with more than one mature femalewere usually covered by the worm sheaths, and were frequentlydamaged (gnarled, torn, silted, etc.). The sternum of infestedcrabs was often damaged due to the projection of worm sheathsthrough it to the subabdominal region. There the egg sacs weredeposited on the pleopods to develop along with the crabembryos.     

Costs and benefits of maternal behaviour in the green lynx spider (Oxyopidae,Peucetia viridans)

I examined the adaptiveness of maternal behaviour in the green lynx spider Peucetia viridans (Hentz), by measuring the costs and benefits to the female of egg-sac tending. P. viridans guards her egg sac for 6–8 weeks until the young have emerged and dispersed. I removed females from egg sacs in the field either immediately after oviposition or after they had guarded the egg sacs for 2 weeks, and compared the fate of these sacs with that of control sacs which had females present throughout. Survival rates of egg sacs were significantly improved by the presence of a female. The major sources of mortality were ant predation and sac dislodgement, both of which were significantly reduced by a guarding female, and mantispid brood parasitism, which was not affected by the female. To measure the spiders' lifetime reproductive output, I allowed caged females to construct egg sacs. Half had their first egg sac removed shortly after oviposition, while half were allowed to guard. Significantly more non-guarding than guarding females produced second egg sacs. Thus for the green lynx spider, egg sac guarding decreases lifetime egg production, but increases offspring survival. Under north Florida conditions, the benefits of guarding outweight the costs, and the females have a higher lifetime reproductive success than if they did not guard.     

Cry1Ab蛋白对拟环纹豹蛛胚胎发育过程中形态和化学物质含量变化的影响

利用稻田蜘蛛优势种拟环纹豹蛛为研究对象,检测Cry1Ab蛋白在拟环纹豹蛛卵囊内的含量及Cry1Ab蛋白对拟环纹豹蛛胚胎发育过程中形态特征的变化、化学物质含量和卵粒内4种保护酶活性的影响。结果表明：在胚胎发育过程中,卵粒中Cry1Ab蛋白含量随发育时间延长而减少,通过对卵粒中的化学物质的测定,发现蛋白质含量水平对照组要显著高于实验组（P〈0.05）,糖和脂肪含量对照组和实验组之间无显著差异。卵粒内超氧化物歧化酶（SOD）、乙酰胆碱酯酶（AchE）、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）4种酶活力除了GSH-Px酶活力实验组高于对照组外,其余3种酶活力均低于对照组。通过石蜡切片和液体石蜡透明观察,实验组较对照组胚胎发育历期延长。该研究证明在胚胎发育时期Cry1Ab蛋白影响了卵粒内SOD、AchE、GSH-Px和CAT酶的活力,且Cry1Ab蛋白对拟环纹豹蛛的胚胎发育产生了一定程度的影响。     

韭菜胚囊发育与胚胎发生

韭菜胚囊发育为葱型,胚胎发生属柳叶菜型。成熟胚囊中,三个反足细胞形态上常类似卵器,其中二个呈助细胞状,一个呈卵细胞状。卵状反足细胞可分裂成多细胞原胚,但随着胚乳的发育而退化。在未受精胚囊中,卵细胞和卵状反足细胞均可分裂,它们的发生过程与合子胚相似,但因无胚乳哺育,均不能继续发育。论证了反足细胞胚的性质,初步探讨了胚乳与反足细胞无配子生殖的关系。     

Maternal defensive behaviors of <Emphasis Type="Italic">Uloborus</Emphasis> sp. (Araneae,Uloboridae): behavioral repertoire and influence of clutch size and female size on female aggressiveness

Maternal care in spiders often involves behaviors associated with the protection of eggs and spiderlings against parasitoids and predators (including conspecifics). The females of several species have been documented to move their egg sacs away from natural enemies or to invest in active defense behaviors against web invaders, such as parasitoid wasps or araneophagic spider species, to protect their brood. In this study, we present observations of protective behavior by Uloborus sp. females carrying egg sacs. We also investigated whether brood size and female size influence female aggressive behaviors and response time against an artificial source of disturbance. Females carrying egg sacs almost immediately perceived and reacted aggressively against the artificial stimulus, whereas females without egg sacs moved away or ran to the web margins, avoiding the source of disturbance. The aggressive response was independent of clutch size and female body size, indicating that all females will risk interacting with potential agents of egg mortality. This systematic response by all females with egg sacs may be important for reducing the incidence of attack by the egg predator wasp Bathyzonus sp. (Ichneumonidae).     

The Gamete-Shedding Substances of Starfishes: A Physiological-Biochemical Study

A shedding substance, found in the radial nerves of 14 speciesof starfish, induced the release of gametes from intact animalsas well as from whole or fragmented gonads. The shedding substancewas not sex-specific, being present in the radial nerves ofboth males and females throughout the year, and, in general,was not species-specific. This neurosecretory-like polypeptideappeared to function by stimulating ovarian muscle to contract,and was calcium-dependent: it also stimulated the maturationof immature eggs. The shedding substance has been purified andits amino acid composition investigated. A second physiologically-active material, termed "shedhibin"because it inhibited shedding activity, was also found in theradial nerves of ripe sea stars. In the presence of shedhibin,normally-adequate quantities of shedding substance would notcause the release of gametes from isolated ovarian fragments.It appeared that although the level of shedding substance wasconstant throughout the year, the level of shedhibin fluctuated,possibly controlling the natural release of gametes from seastars. The precise chemical nature of shedhibin has yet to bedetermined.     

The utilization of lipovitellin during blue crab (Callinectes sapidus) embryogenesis

Embryos of the blue crab Callinectes sapidus develop in egg sacs carried on the abdomen of the female. They develop over a period of 10-13 days at 28 degrees C and are nutritionally dependent on yolk until they emerge from the egg sacs as free-swimming zoeae. The principal component of blue crab yolk is lipovitellin (LpII), a water-soluble lipoprotein composed of approximately equal amounts of lipid and protein. We followed changes in the concentration of apoproteins of LpII during embryogenesis by ELISA and Western blots, using monoclonal antibodies against two LpII apoprotein associated peptides identified as Protein A (107 kDa) and Protein B (75 kDa). During embryogenesis there was a decrease in Protein B but an increase in two smaller peptides (52 and 35 kDa) that reacted with the Protein B antibody. Utilization of LpII during embryogenesis was also followed morphologically by immunohistochemistry. Utilization of LpII was slow in early embryonic stages, followed by rapid utilization in late embryonic stages, such that only traces of LpII were present at the end of embryogenesis. The cells of the developing hepatopancreas appear to play an important role in the utilization of LpII.     

An arboreal spider protects its offspring by diving into the water of tank bromeliadsUne araignée arboricole utilise les réservoirs d’eau des broméliacées pour se protéger et protéger son cocon

Cupiennius salei (Ctenidae) individuals frequently live in association with tank bromeliads, including Aechmea bracteata, in Quintana Roo (Mexico). Whereas C. salei females without egg sacs hunt over their entire host plant, females carrying egg sacs settle above the A. bracteata reservoirs they have partially sealed with silk. There they avoid predators that use sight to detect their prey, as is known for many bird species. Furthermore, if a danger is more acute, these females dive with their egg sacs into the bromeliad reservoir. An experiment showed that this is not the case for males or females without egg sacs. In addition to the likely abundance of prey found therein, the potential of diving into the tank to protect offspring may explain the close association of this spider with bromeliads. These results show that, although arboreal, C. salei evolved a protective behavior using the water of tank bromeliads to protect offspring.     

锯缘青蟹主要过敏原的纯化与鉴定

以锯缘青蟹为研究对象,从免疫鉴定、分离纯化、抗体制备和免疫学分析等方面对其主要过敏原进行研究。首先利用过敏者血清的免疫印迹法,确定锯缘青蟹的主要过敏原为分子量约38kD的蛋白。然后通过制备丙酮粉、等电点沉淀、硫酸铵沉淀及加热处理对分子量为38kD的主要过敏蛋白进行了高度纯化。该蛋白的pI约为4.5,与虾的原肌球蛋白Pena1性质相近,证实了锯缘青蟹的主要过敏原为原肌球蛋白。通过免疫新西兰大白兔,制备了原肌球蛋白的抗血清,采用Protein A Sepharose亲和层析柱对动物抗体进行了纯化。该抗血清效价高,经4×105倍稀释后仍能与抗原进行反应。该抗体与甲壳类动物及软体动物的原肌球蛋白具有较强的免疫交叉反应,可用于食品过敏原检测。       

THE SARCOPLASMIC RETICULUM, THE T SYSTEM, AND THE MOTOR TERMINALS OF SLOW AND TWITCH MUSCLE FIBERS IN THE GARTER SNAKE

Twitch and slow muscle fibers, identified morphologically in the garter snake, have been examined in the electron microscope. The transverse tubular system and the sarcoplasmic reticulum are separate entities distinct from each other. In twitch fibers, the tubular system and the dilated sacs of the sarcoplasmic reticulum form triads at the level of junction of A and I bands. In the slow fibers, the sarcoplasmic reticulum is severely depleted in amount and the transverse tubular system is completely absent. The junctional folds of the postsynaptic membrane of the muscle fiber under an "en grappe" ending of a slow fiber are not so frequent or regular in occurrence or so wide or so long as under the "en plaque" ending of a twitch fiber. Some physiological implications of these differences in fine structure of twitch and slow fibers are discussed. The absence of the transverse tubular system and reduction in amount of sarcoplasmic reticulum, along with the consequent disposition of the fibrils, the occurrence of multiple nerve terminals, and the degree of complexity of the post junctional folds of the sarcolemma appear to be the morphological basis for the physiological reaction of slow muscle fibers.     

A new culture system for in situ observation of the growth and development of Eucyclops serrulatus (Copepoda: Cyclopoida)

A practical and convenient method of rearing Eucyclops serrulatus in a microculture environment is described. A complete life cycle of E. serrulatus was maintained in a narrow space on a microscope slide glass on which a cover glass of 22 x 40 mm in size was mounted at a height of 0.8 mm. The culture medium was constituted by bottled mineral water boiled with grains of Glycine max (soybean). Chilomonas paramecium, a free-living protozoan organism, was provided as live food. Growth of nauplii hatched from eggs to the first stage of copepodite took an average of 7.7 days, and the growth of copepodite 1 to the egg-bearing adult female took an average of 20.1 days in the microculture cell with an average life time of 44.7 days. Continuous passage of copepods was successfully maintained as long as sufficient medium and food were provided. The microculture method enables an in situ microscopic observation on the growth and developmental process of helminth larvae experimentally infected to copepods as well as of copepod itself. Furthermore, it does not require anesthetization and, therefore, minimize the amount of stress exposed to copepods during the handling process.     

Evidence for the copepods Acanthocyclops robustus and Mesocyclops edax as competent intermediate hosts for Coelomomyces punctatus during an epizootic in a larval population of the mosquito Anopheles quadrimaculatus.

Field and laboratory experiments were conducted during an epizootic of Coelomomyces punctatus (Chytridiomycetes: Blastocladiales) in a population of the mosquito Anopheles quadrimaculatus in a North Carolina farm pond to examine the interactions of several potential copepod hosts with the mosquito and fungus. The diel vertical migratory behavior of the copepod species Acanthocyclops robustus, Eucyclops serrulatus, Macrocyclops albidus, and Mesocyclops edax were monitored in relation to infection rates in sentinel mosquito larvae. Mosquito infection occurred primarily around dusk, the same period during which A. robustus and E. serrulatus were most abundant near the surface of the pond. However, exposure of A. robustus, E. serrulatus, M. albidus, M. edax, Microcyclops varicans, and Paracyclops poppei to fungal meiospores in the laboratory showed that only A. robustus and M. edax were competent intermediate hosts for C. punctatus. Laboratory studies of the diel periodicity of gametangial dehiscence in A. robustus and M. edax infected with C. punctatus revealed that gamete release and zygote formation also occurred around dusk. The combined results of the laboratory and field studies on copepod abundance, susceptibility to infection, and periodicity of gametangial dehiscence suggest that A. robustus was the principal intermediate host for C. punctatus during the epizootic, though it is probable that M. edax also contributed importantly to the overall rate of larval infection.