Aspects of the Differentiation of the Egg of the Moss Physcomitrium coorgense Broth

Oogenesis in Physcomitrium coorgense follows the course seenin lower archegoniates generally. However no evidence was foundof cytoplasmic autophagy, or, during maturation of the egg,of nucleo-cytoplasmic interaction of the kind reported in liverwortsand ferns. The internal lamellar system of the plastids dedifferentiatesalmost entirely, and there is a corresponding increase in thefrequency of osmiophilic droplets. Starch also disappears, andsimultaneously large quantities of mucilage appear in the cytoplasm.The mucilage is secreted into the venter of the archegoniumand envelopes the egg. The egg lacks a special osmiophilic membrane.     

Nucleocytoplasmic Interaction During Maturation of the Egg of the Fern Histiopteris incisa (Thunb.) J. Smith

The maturing egg of Histiopteris incisa has many features incommon with that of Pteridium, with which the species may berelated. The nuclear evaginations are however conspicuous inrespect of the extensive development of internal membrane systems,involving dilatation of the perinuclear space. In some in stancesthe inner membrane of the nuclear envelope, the proliferationof which gives rise to the dilatations, was strikingly tenuous,possibly indicating an extensive interchange between the perinuclearspace and that part of the nucleoplasm sequestered in the evaginations.The evaginations frequently contain an aggregate of electron-opaquematerial resembling structurally and in staining propertiessimilar aggregates in Pteridium, but in contrast to Pteridiumthere was no evidence that these aggregates were organized inor near the nucleolus. Histiopteris inciso (Thunb.)J. Smith, Pteridophyta, egg maturation, nucleocytoplasmic interaction, ultrastructure     

家蚕保存系统红色卵的遗传分析

用遗传背景清楚的家蚕Bombyx mori红卵（re）、白卵(w-2、pe)、第4褐卵（b-4）的标志基因系统和正常型黑卵系统与我国家蚕基因库保存的20个红色卵系统杂交,进行顺反测验,分析了它们的卵色支配基因及遗传规律。结果发现：①在03-310系统中存在家蚕卵色新突变pink egg,与红卵re 等位,基因符号为re^p,表型特征为：卵淡红色,成虫蛾眼也为淡红色;②6个系统为红卵（re）的纯合系统,还有５个系统除具有re／re基因型外,还具有支配白色卵或浅红色或橙红色卵的突变基因;③２个系统为第4褐卵（b4）的纯合系统; ④6个系统的红褐色卵为母性影响遗传;⑤发现家蚕卵色基因b-4和r-e的互补关系,b-4/b-4 re/re基因型表现为新的卵色——橙黄色。     

甜菜夜蛾围食膜肠粘蛋白基因SeM-8的克隆、序列分析及在不同组织中的表达检测

昆虫肠粘蛋白（invertebrate intestinal mucin, IIM）是围食膜（peritrophic membrane, PM）的重要蛋白组分之一,在保护昆虫免受微生物侵染方面起着非常重要的作用。本研究以甜菜夜蛾Spodoptera exigua 5龄幼虫中肠总RNA为模板,根据已知的甜菜夜蛾肠粘蛋白SeIIM-8基因的cDNA序列（GenBank登录号：ABW06596）设计引物,利用RT-PCR技术扩增得到甜菜夜蛾肠粘蛋白基因SeM-8,序列分析发现其开放阅读框（open reading frame, ORF）长2 703 bp,编码900个氨基酸残基,预测分子量为95.7 kDa。序列分析表明,其氨基酸序列（GenBank登录号：GU255994）与棉铃虫Helicoverpa armigera（Hübner）,粘虫Mamestra configurata和小菜蛾Plutella xylostella肠粘蛋白的一致性分别为48%,49% 和45%。Western blot分析结果表明,SeM-8粘蛋白在甜菜夜蛾即将孵化的卵和5龄幼虫的围食膜、中肠和粪便中都有存在,在5龄幼虫马氏管、脂肪体、唾腺、血淋巴等组织部位没有发现。本研究为进一步研究IIM结构和功能,寻找生物防治新靶标奠定了理论基础。     

菜蛾盘绒茧蜂卵携带的免疫抑制因子

抑制寄主昆虫的免疫反应是内寄生蜂存活的关键。菜蛾盘绒茧蜂Cotesia vestalis（Haliday）寄生小菜蛾Plutella xylostella （L.）幼虫后,蜂卵如何逃避和抑制寄主的免疫攻击,尚未得到全面揭示。本文采用电镜技术系统观察了菜蛾盘绒茧蜂卵表面的超微结构。结果显示：蜂卵表面覆盖有纤维层和絮状的类病毒样纤丝（VLFs）,同时携带了含多分DNA病毒粒子（PDV）的萼液。在寄生初期,包裹在蜂卵表面的纤维层和VLFs首先起到保护蜂卵不被小菜蛾血细胞包囊的被动防御作用。随后,PDV发挥主动的免疫抑制作用。通过假寄生手段,证明了菜蛾盘绒茧蜂PDV (CvBV) 具有较持久的克服寄主免疫攻击的能力,是主要的免疫抑制因子。在假寄生后连续8 d的观察时间内,菜蛾盘绒茧蜂的蜂卵均未被包囊。结果提示,在菜蛾盘绒茧蜂-小菜蛾寄生体系中,菜蛾盘绒茧蜂采取被动防御和主动攻击两种方式应对寄主小菜蛾的免疫攻击。     

Adaptive evolution of sperm bindin tracks egg incompatibility in neotropical sea urchins of the genus Echinometra

Bindin is a gamete recognition protein known to control species-specificsperm-egg adhesion and membrane fusion in sea urchins. Previousanalyses have shown that diversifying selection on bindin aminoacid sequence is found when gametically incompatible speciesare compared, but not when species are compatible. The presentstudy analyzes bindin polymorphism and divergence in the threeclosely related species of Echinometra in Central America: E.lucunter and E. viridis from the Caribbean, and E. vanbruntifrom the eastern Pacific. The eggs of E. lucunter have evolveda strong block to fertilization by sperm of its neotropicalcongeners, whereas those of the other two species have not.As in the Indo-West Pacific (IWP) Echinometra, the neotropicalspecies show high intraspecific bindin polymorphism in the samegene regions as in the IWP species. Maximum likelihood analysisshows that many of the polymorphic codon sites are under mildpositive selection. Of the fixed amino acid replacements, mosthave accumulated along the bindin lineage of E. lucunter. Weanalyzed the data with maximum likelihood models of variationin positive selection across lineages and codon sites, and withmodels that consider sites and lineages simultaneously. Ourresults show that positive selection is concentrated along theE. lucunter bindin lineage, and that codon sites with aminoacid replacements fixed in this species show by far the highestsignal of positive selection. Lineage-specific positive selectionparalleling egg incompatibility provides support that adaptiveevolution of sperm proteins acts to maintain recognition ofbindin by changing egg receptors. Because both egg incompatibilityand bindin divergence are greater between allopatric speciesthan between sympatric species, the hypothesis of selectionagainst hybridization (reinforcement) cannot explain why adaptiveevolution has been confined to a single lineage in the AmericanEchinometra. Instead, processes acting to varying degrees withinspecies (e.g., sperm competition, sexual selection, and sexualconflict) are more promising explanations for lineage-specificpositive selection on bindin.     

The Structure of the Gonads, Gametogenesis, and Sperm-Egg Interactions in the Anthozoa

In the Anthozoans Metridium sp. and Bunodosoma cavernata thetestes are located in the secondary septa. The cysts of thetestis are surrounded by mesoglea. Bounding the mesoglea oneach side of the septa is the gastrodermis. The gastrodermalcells exhibit interesting flagellar specializations. Each cellhas a flagellum which extends into the gastrovascular cavityand is surrounded by long microvillus-like extensions. It issuggested that these specializations may serve in a sensorycapacity. The periphery of the testicular cysts contains the early spermatogenicstages, while spermatids and sperm are more centrally located.In both Metridium sp. and B. cavernata the early spermatidsare connected by intercellular bridges. These spermatids exhibitearly flagellar formation. The distal centrioles have two associatedspecializations, satellites and pericentriolar processes. Duringspermiogenesis there is a general polarization of the cytoplasmand several maturational events occur more or less simultaneously.Nuclear condensation begins, mitochondria aggregate and fuse,and lipid-like inclusions associate with this mitochondrialcomplex. Concave or "donut" shaped vesicles are noted in associationwith Golgi complexes. The sperm of both species contain electron dense nuclei, lackdistinct acrosomes but have vesicles associated with the lateralsides of their heads between the nuclear envelopes and plasmamembranes. In both sperm, lipid-like inclusions are associatedwith complex mitochondrial bodies. The sperm of Metridium exhibit an interesting membrane responsewhen exposed to eggs. The plasma membrane along the side ofthe head of the sperm sends out long finger-like protrusions. The eggs of both Metridium sp. and B. cavernata exhibit corticalreactions. In Metridium the dehisced cortical substance appearsto be lost to the environment, while in B. cavernata it formsa flocculent coat around the egg.     

Structural characterization of glycosphingolipids from the eggs of Schistosoma mansoni and Schistosoma japonicum

The granulomatous pathology in human intestinal schistosomiasisis induced primarily by the egg antigens of schistosome, a parasitictrematode. Glycolipids and glycoproteins were extracted fromthe eggs of the two major species which infect human, Schistosomamansoni and Schistosoma japonicum, for structural characterizationbased on highly sensitive mass spectrometric analysis coupledwith chemical derivatization. Here, we demonstrate that a seriesof uniquely multifucosylated glycosphingolipids constitute themajor egg glycolipids of S.mansoni but not of S.japonicum. TheS.mansoni glycosphingolipids were found to be extended by varyingnumbers of an unusual repeating unit,     

Fine Structural Analysis of Animal Cell Surfaces: Membranes and Cell Surface Topography

Current research on the mechanism of transmembrane regulationof topographic modulation at the cell surface is described forthe sea urchin egg and Sarcoma 180 ascites tumor cells of SwissWebster white mice. The transmembrane system is characterizedin terms of three components: glycocalyx, membrane, and cytofibrillarstructures. The importance of membrane molecular architectureper se relative to the other surface components is assessedin terms of freeze fracture analysis of both cell types as wellas concanavalin A (ConA)-mediated long term agglutination, cytochalasinB effects, and other drug-induced changes at Sarcoma 180 cellsurfaces. A quantitative and qualitative assessment of intramembranousparticle (IMP) sizes and density distributions reveals intrinsicstructural changes of the fusing membranes at cortical reactionduring sea urchin egg fertilization and also with the post-fertilizedaccumulation of surface microvilli. Comparable changes in IMPare noted for microvillus retraction and membrane smoothingin Sarcoma 180 cells under a variety of experimental conditions.On the other hand, chemical perturbation of S-180 cell surfacesreveals a rather non-ubiquitous, though identifiable, involvementof microfilaments and no microtubule involvement in these topographicchanges. These observations suggest that the plasma membraneis a dynamic structure poised between "restrictive" and "lessrestrictive" states of fluidity or deformability and, hence,is a determinant component in topographic change.     

Ultrastructural Aspects of Fertilization in Spiralian Eggs

Normally, the eggs of Spisula are monospermic. How polyspermyis prevented in this organism is unclear, particularly whenthe cortex of the fertilized ovum is examined. Using conventionalmicroscopic procedures, little alteration of the surface ofthe egg is observed following insemination; the microvilli,vitelline layer and cortical granules are morphologically unchanged.Investigations employing freeze fracture replication of fertilizedand unfertilized Spisula eggs demonstrate that there is a dichotomywith respect to the distribution of intra membranous particleswithin the plasmalemma of Spisula eggs. There is a structuralreorganization of microvilli and a two-fold increase in particleson the A-face of the plasma membrane along their bases followinginsemination. These transformations in microvillar structureand intramembranous particle number may be involved in establishinga block to polyspermy, however, further evidence is necessaryto demonstrate a cause-effect relation.     

Pigment ingestion and egg production rates of the calanoid copepod Temora longicornisr. implications for gut pigment loss and omnivorous feeding

We examined the relationship between egg production rate (E)and pigment ingestion rate (I, from gut content corrected for33% loss) for adult female Temora longicornis in Long IslandSound on 47 occasions. Linear regression of E on I [both variablesexpressed in mass of nitrogen (N) female^–1 day^–1]was: E_N = 0.0016 + 0.770 x I_N. The slope, 0.77, is the apparentgross efficiency of egg production, equivalent to the grossgrowth efficiency (GGE) assuming that females partition allnitrogen for growth into egg production. Published work suggeststhat a GGE of 0.37 would be expected for herbivorous copepods.The discrepancy between the expected value of 0.37 and observedvalue of 0.77 could result from unquantified losses of gut pigmentor because T.longicomis ingested a significant amount of nitrogenby feeding as a carnivore. We suggest that if T.longicomis femalesderive all of their nitrogen for growth by feeding on phytoplankton,and if no correction for pigment loss is employed, then thegut pigment method underestimates pigment ingestion by no morethan a factor of two.     

Estimation and interpretation of egg provisioning in marine invertebrates

Per-offspring maternal investment is an integral part of life-historytheory. To understand the evolution of per-offspring maternalinvestment in marine invertebrates, a number of mathematicalmodels have been developed. These models examine how selectionaffects the proportion of maternally derived egg energy usedto produce a newly metamorphosed juvenile (s) and make predictionsabout the distribution of s in nature. However, there are veryfew published values of s and therefore it is difficult to evaluatehow well these models match nature. We present several equationsto empirically estimate values of s for any group of marineinvertebrate, and use data from echinoderms to compare the differentequations. The calculations that directly estimate s requireinformation on the amount of egg energy, juvenile energy, andenergy metabolized during development. Currently, there arefew data available for directly estimating s, and thus generatingdistributions of s derived from direct estimates is not possible.Furthermore, the direct estimations of s are informative forplanktotrophy but not for lecithotrophy. We have developed anequation that can be used to directly estimate s for lecithotrophs.The calculations to indirectly estimate s only require egg energyor egg size for the species in question and the value of s andegg energy or size for a reference species. This reference speciesreplaces the need to measure juvenile energy and energy metabolizedduring larval development. Because egg energy or size is currentlyavailable for many species, the indirect estimates will be usefulfor generating distributions of s, and will allow comparisonswith models. Although these indirect methods are good for generatingdistributions of s, they do not provide reliable estimates ofs for any particular species. Estimating values of s to comparemodels is a critical gap in our current evaluations of marineinvertebrate life-history models.     

Partner fidelity and egg reciprocation in the simultaneously hermaphroditic polychaete worm Ophryotrocha diadema

The mating system of the simultaneously hermaphroditic polychaeteworm Ophryotrocha diadema consists of a regular egg exchangebetween partners of a pair. Such reciprocal egg exchange hasbeen considered a form of cooperation, where one partner cooperatesby offering its eggs to be fertilized and expects to receivepartner's eggs to fertilize. Frequency of cases in which hermaphroditescheated (i.e., failed to give up eggs at their turn) and responsesto cheating were estimated by analyzing the behavior of 38 triplets of ovigerous hermaphrodites over a 2-week period. Thepartner did not reciprocate 8% of egg layings. The cheatedpartner did not detect most cases of cheating (16 out of 25).Such a low frequency of cheating can explain why no retaliationmechanism evolved in this species. Sixty-eight percent of the individuals from the original pairs deserted even if their partnersnever cheated them; therefore, cheating cannot be consideredthe cause of desertion. Rather, desertion appeared to be aconsequence of availability of a new partner whose oocyteswere riper than those of the old partner. It occurred becausethe opportunity arose for an immediate reward, indicating thatO. diadema egg exchange differs from that originally describedin some serranid fish as egg trading. The relationship betweencosts of desertion and population size is discussed.     

空心莲子草叶甲室内大量繁殖研究

为了大量繁殖供环境释放的空心莲子草叶甲Agasicles hygrophila以实现空心莲子草区域减灾, 我们探索出室内大量饲养与繁殖空心莲子草叶甲的方法与流程, 包括用叶片法或苗水培法孵化卵粒、用盒养法饲养各龄幼虫与成虫并供成虫产卵、用栽培活苗笼养法化蛹羽化。在室内成虫终日均能取食、交配、产卵, 产卵前期约4～5 d, 产卵高峰期在羽化后第7～24 天, 每雌平均产卵21.08块, 约570粒。盒养法叶片平均可着卵4.28块, 叶背与叶面着卵量相近; 笼养法叶片平均着卵为1.46块, 卵主要产于叶背。盒养法与笼养法得到的卵孵化率分别为94.02%与92.50%。空心莲子草叶甲除化蛹需在栽培活苗上完成外, 各龄幼虫与成虫均可用离体新鲜苗盒养法密集饲养。初孵1龄幼虫转株（叶）期、3龄老熟幼虫转化蛹苗期是室内大量饲养与繁殖空心莲子草叶甲的关键时期, 高密度成功饲养与繁殖空心莲子草叶甲的最适化蛹接虫量是每株8头, 产卵期雌虫的最适密度是每株5头。     

Fitness costs and benefits of cowbird egg ejection by gray catbirds

Gray catbirds (Dumetella carolinensis) eject over 95% of brown-headedcowbird (Molothrus ater) eggs placed into their nests. Ejectionbehavior could be maintained by selection from either: (1) cowbird parasitism, if the costs of accepting a cowbird egg outweighthe costs of ejecting it, or (2) conspecific parasitism, ifsuch parasitism occurs naturally and results in ejection. Thisstudy tested the above hypotheses by measuring the cost ofacceptance of cowbird parasitism (n= 38 experimentally introducedcowbird chicks) and of cowbird egg ejection (n = 94 experiments),as well as the frequency of natural conspecific parasitismamong 229 catbird nests observed and the frequency of conspecific egg ejection (n = 27 experiments). The conspecific parasitism hypothesis was not supported because catbirds accepted all foreignconspecific eggs placed into their nests, and no natural conspecificbrood parasitism was detected at any nests. The cowbird parasitismhypothesis was strongly supported because the cost of acceptinga cowbird chick (0.79 catbird fledglings) is much greater thanthe cost of ejecting a cowbird egg (0.0022 catbird fledglingsper ejection).     

The evolution of egg size in the brood parasitic cuckoos

We compared genera of nonparasitic cuckoos and two groups ofparasitic cuckoos: those raised together with host young ("nonejectors")and those in which the newly hatched cuckoo either ejects thehost eggs or chicks, or kills the host young ("ejectors"). Nonejectorsare similar to their hosts in body size and parasitize largerhosts than do ejectors, which parasitize hosts much smallerthan themselves. In both types of parasite, the cuckoo's eggtends to match the host eggs in size. To achieve this, nonejectorshave evolved a smaller egg for their body size than have nonparasiticcuckoos, and ejectors have evolved an even smaller egg. Amongejector cuckoo genera, larger cuckoos have larger eggs relativeto the eggs of their hosts, and the relationship between cuckooegg volume (mass of the newly-hatched cuckoo) and host egg volume(mass to be ejected) did not differ from that predicted by weight-liftingallometry. However, comparing among Cuculus cuckoo species,the allometric slope differed from the predicted, so it is notclear that egg size is related to the need to give the cuckoochick sufficient strength for ejection. Comparing the two mostspeciose ejector genera, Chrysococcyx cuckoos (smaller and parasitizedome-nesting hosts) lay eggs more similar in size to their host'seggs than do Cuculus cuckoos (larger and parasitize open cup–nestinghosts). Closer size-matching of host eggs in Chrysococcyx mayreflect the following: (1) selection to reduce adult body massto facilitate entry through small domed nest holes to lay, and(2) less need for a large egg, because longer incubation periodsin dome-nesting hosts allow the young cuckoo more time to growbefore it need eject host eggs.     

Egg size and reproductive allocation in eusocial thrips

Reproductive allocation, in terms of fecundity and egg size,has been given little consideration in eusocial societies. Tobegin to address this, absolute and body size–adjustedegg volumes were compared, along with fecundity, between thefoundress and her subfertile soldier offspring in the eusocial,gall-inducing thrips, Kladothrips hamiltoni, Kladothrips waterhousei,and Kladothrips habrus, and a congeneric, Kladothrips morrisi,with fully fecund soldiers. Soldiers produced significantlylarger eggs than the foundress in all species except K. morrisi,where egg volumes did not differ. After accounting for bodysize, soldiers produced significantly smaller eggs than thefoundress in K. morrisi and marginally so in K. waterhousei,but egg sizes did not differ in K. hamiltoni and K. habrus.When egg size and fecundity data are combined, K. morrisi soldiersinvest less in reproduction than the foundress, and in conjunctionwith other life-history features the species can be consideredeusocial. Maximum likelihood analyses reveal relatively lowreproductive allocation skew in the ancestral lineages and highskew in the derived lineages, but the trend is not significantwhen fecundity and egg size are considered separately. Gallsize covaried negatively with soldier-to-foundress relativebody size–adjusted egg size and reproductive allocationand marginally so with fecundity, suggesting that gall sizeis a determinant of egg size and fecundity trade-offs in eusocialthrips and providing the strongest support to date that gallsize has featured in the social evolution of this clade. Thisstudy highlights that data on fecundity alone may be insufficientfor assessing reproductive division of labor.     

Megasporogenesis and the Subsequent Cell Lineage Within the Ovule of Taxus baccata L.

Megasporogenesis in Taxus led to a T-shaped tetrad, the mitochondriaand plastids being largely confined to the chalazal megaspore,the only spore to show further development. Germination of themegaspore followed very soon after its formation. The femalegametophyte was initially coenocytic but after about one monthit became cellular, new walls arising between the nuclei inpositions marked out by accumulations of cisternae of endoplasmicreticulum. No ‘secondary spindles’ or other formsof microtubular participation in the siting of these walls couldbe detected. The development of the archegonia could not be resolved withcertainty, but it seemed likely that the cell analogous to thecentral cell of the pteridophyte archegonium eventually becamethe egg cell. The cytoplasm of the egg cell was clearly zoned.Prominent in the outer cytoplasm were granular bodies, 2–5µm in diameter, identifiable with the ‘grandes inclusions’described from the egg cells of conifers. The evidence pointedto their being derived from hypertrophied plastids which hadencapsulated part of the cytoplasm, a view strengthened by thecomplete absence of recognizable plastids from the mature cell.Bundles of microtubules radiating from the nuclear envelopewere a conspicuous feature, possibly stabilizing the zonationof the cytoplasm. Megasporogenesis, Taxus baccata, egg cell, ‘grandes inclusions’     

Zooplankton growth rates: diel egg production in the copepods Oithona, Euterpina and Corycaeus from tropical waters

Clear diel periodicity in the timing of egg laying was observedin the tropical cyclopoid cope-pods Oithona plumifera, Oithonanana, Oithona simplex and Corycaeus amazomcus, and the harpacti-coidEuterpina acutifrons in waters surrounding Jamaica, West Indies.Individual females incubated under ambient food conditions formultiple clutches displayed remarkable constancy in their clutchdurations (= egg or embryonic development time). All speciesexhibited clutch durations of 20–23 h and cycle durations(= sum of clutch and inter-clutch durations) of 24 h, exceptfor the offshore species O.plumifera where the clutch durationwas 36 h and the cycle duration 48 or 72 h. Egg laying appearedto be synchronized by photoperiod, occurring around dawn formost species. In order to avoid biases, diel periodicity mustbe accounted for in estimates of egg production rates, and futureefforts should concentrate on the responses of clutch size andinterclutch durations to natural food climates.     

Fitness costs and benefits of antipredator behavior mediated by chemotactile cues in the wolf spider Pardosa milvina (Araneae: Lycosidae)

Animals may exhibit a variety of defensive behaviors in thepresence of indirect predator cues. Such behavior offers immediatefitness benefits but may also incur substantial foraging andreproductive costs. We measured shifts in space use (verticalclimbing) by the wolf spider Pardosa milvina induced by chemotactilecues (silk and excreta) from a co-occurring predatory wolfspider Hogna helluo. We then measured foraging and reproductive costs, as well as survival benefits, of this behavior. For 2weeks, we maintained mated adult female Pardosa in plasticcontainers with one of three treated peat moss substrates:a container previously occupied by a conspecific for 3 days,a container previously occupied by an adult Hogna for 3 days,and a container devoid of either cue (control). We measuredprey capture efficiency, body condition, egg sac production,egg sac weight, and egg number for individuals in each treatment.We also counted the number of Pardosa that survived and exhibitedclimbing behavior in the presence of a live Hogna with andwithout silk and excreta cues. Pardosa climbed container wallssignificantly more often in the presence of Hogna silk andexcreta relative to other treatments. Pardosa exposed to Hognacues coupled with live Hogna survived significantly longerthan spiders that had no predator cues available. Pardosa placedin containers with Hogna cues, but no Hogna, lost weight morequickly, ate fewer prey, were in poorer body condition, producedlighter egg sacs, and produced fewer eggs than spiders in controlor conspecific treatments.