Ultrastructure of sperm development and mature sperm morphology in three species of commensal bivalves (Mollusca: Galeommatoidea)

Ultrastructural features of the ovotestes, spermatogenesis, and the mature sperm are described for three galeommatid bivalves, Divariscintilla yoyo, Divariscintilla troglodytes, and Scintilla sp., from stomatopod burrows in eastern Florida. All three species yielded similar results except with respect to mature sperm dimensions. The ovotestis contains three types of somatic cells within the testicular portion: flattened myoepithelial cells defining the outer acinal wall; underlying pleomorphic follicle cells containing abundant glycogen deposits; and scattered, amoeboid cells containing lysosomal-like inclusions which are closely associated with developing sperm. Early spermatogenesis is typical of that reported from other bivalves. In contrast, the late stages of spermiogenesis involve the migration and gradual rotation of the acrosomal vesicle, resulting in a mature acrosome tilted about 70° from the long axis of the cell. The mature sperm possesses an elongated, slightly curved nucleus; a subterminal, concave acrosome with a nipple-like central projection; five spherical mitochondria and two centnoles in the middlepiece; and a long flagellum. The rotational asymmetry and the presence of perimitochondrial glycogen deposits in these sperm are unusual in the Bivalvia and may be associated with fertilization specializations and larval brooding common among galeommatoideans.     

Comparison studies on the effects of ultraviolet irradiation on photosynthesis

1. 1. A comparison of chloroplasts from which plastoquinone had been extracted with ultraviolet irradiation supports the conclusion that plastoquinone destruction is not the major cause of ultraviolet inhibition of photosynthesis. No photodestruction of chloroplast lipids, carotenoids or soluble proteins by ultraviolet irradiation was detected.

2. 2. Phenazine methosulfate-mediated cyclic photophosphorylation and variable yield fluorescence were inhibited at the same rate as the Hill reaction. Examination of fluorescence emission spectra of chloroplasts and whole algal cells revealed decreases in both the 685-nm and long-wavelength emission peaks.

3. 3. Digestion of chloroplasts with lipase decreased fluorescence in a manner similar to ultraviolet irradiation. Hill reaction activity was also inhibited by lipase digestion.

4. 4. It is concluded that the inhibition of photosynthesis by ultraviolet irradiation is most likely due to a disruption of the structural integrity of the lamellar membranes which results in the loss of System II activity and associated reactions.

Cytogenetic effects of cyclophosphamide on mouse spermatogonia

Summary NMRI mice were treated with single doses of cyclophosphamide (Cytoxan) and spermatogonia were analysed for chromosome aberrations at various time intervals after treatment.The maxima of aberrations were found 24 hrs p.i. Chromatid type aberrations were observed exclusively. About half of the aberrations consisted of chromatid interchanges, 92% of which exchanging short arm fragments close to the centromeric region.The lack of meiotic multivalents in diakinesis-metaphase I after treatment of spermatogonia stem cells with cyclophosphamide in the study of leonard and Linden (1972) is discussed.

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Zusammentassung NMRI-Mäuse erhielten einmalig eine Applikation von Endoxan in verschieden hoher Dosierung. Zu verschiedenen Zeiten nach der Behandlung wurden Tiere getötet und die Spermatogonien analysiert.Das Maximum der induzierten Effekte lag bei 24 Std p.i. Es gelangten ausschließlich Chromatidentypaberrationen zur Beobachtung, die annähernd zur Hälfte aus Chromatidenaustauschen bestanden. Dabei handelte es sich überwiegend (92%) um Segmentaustausche im zentromernahen Bereich.Der fehlende Nachweis von Multivalenten in der Diakinese-Metaphase I nach Behandlung spermatogonialer Stammzellen mit Cyclophosphamid (Leonard u. Linden, 1972) wird diskutiert.

     

Aflagellate sperm in three species of leptophlebiidae (Ephemeroptera)

Immotile spermatozoa of 3 species of Ephemeroptera, Habroleptoides umbratilis, Habrophlebia eldae and Choroterpes picteti (Leptophlebiidae) are described. In all 3 species, sperm present a coccoidal shape and lack flagella or microtubule systems. Habrophlebia eldae shows very atypical sperm with a roundish nucleus and scarce cytoplasm, including an apical acrosome. By contrast, a fibrillar perforatorium and a mitochondrion are present in the sperm of H. umbratilis and C. picteti. This latter species also shows electron-dense bodies located in the space between the nucleus and the cell membrane. Our findings suggest that sperm/egg interaction should depend in leptophlebiids on the contraction of the genital duct muscles.     

Morphogenetic effects of precocenes on three aphid species

The disruptive effects of precocenes I, II and III on metamorphosis were assessed in apterous viviparae of Acyrthosiphon pisum, Aphis fabae and Megoura viciae. Prenatally applied precocene I had no effect, precocene II caused supernumerary moulting (metathetely) in M. viciae but precocene III induced both precocious adult development (prothetely) and metathetely in all three species. the latter compound also promoted precocious adult development in alate virginoparae, males and ovipara-producers of M. viciae. However, gynoparae of A. fabae, and oviparae of M. viciae and A. pisum were resistant to this action. When topically applied to young adults of A. fabae or M. viciae none of the precocenes caused alate progeny to be produced but all did so in A. pisum. However, the previous supposition that precocene II promotes wing development because it decreases juvenile hormone titres should be viewed with caution as: (a) Precocene II was more potent than precocenes I and III when inducing wing formation but did not provoke precocious adult development, an overt indication of low juvenile hormone titres. (b) Precocene I and III were equally effective in inducing alate progeny but only the latter provoked precocious adult development. (c) Attempts to prevent or reduce the alata-inducing property of precocene II with juvenile hormone I were unsuccessful.     

Differential effects of ammonium and nitrate on three heathland species

Arnica montana and Cirsium dissectum, typical of species-rich heathlands and acidic grasslands, have declined rapidly in The Netherlands in recent years. Field surveys suggest that the decline is caused by soil acidification as a result of enhanced atmospheric N and S deposition. Therefore, the survival, growth and development of these species were studied in a water culture experiment, using nutrient solutions which differed both in mineral nitrogen form and in ammonium concentration. For comparison, the performance of a third, acid tolerant species, Calluna vulgaris, was studied. The results showed that both Arnica and Cirsium performed better using nitrate than when using ammonium as a sole nitrogen source, whereas ammonium toxicity became apparent when ammonium concentrations were raised above 100 µM. Ammonium toxicity was expressed by an increase in mortality of Arnica plants with increasing ammonium concentrations and by a reduction of biomass in Arnica and Cirsium. Furthermore, cation concentrations in both roots and shoots decreased when ammonium was supplied as a nitrogen source. In contrast, Calluna showed optimal development when using ammonium as a sole nitrogen source. In this species, only root biomass was negatively affected by high ammonium concentrations. The ecological implications of these preferences are discussed in relation to soil acidification.     

Comparison of frequencies of complete and incomplete translocations induced in mature sperm of Drosophila]

A frequency of induction of translocations taking place in mature sperm of Drosophila between heterochromatic portions of the 2L compound and 2R acrocentric was estimated to be 9.62 X 10(-3). This value is being compared with the previously estimated frequency of incomplete translocations in this system which is (2.5-2.9) X 10(-3). The ratio of frequencies of complete and incomplete translocations obtained was intermediate between the Panshin data, on the one hand, and those of Muller and Hershkowitz, on the other. The reasons for these discrepancies are under discussion. Based on the value obtained for this ratio, the probability of reunion of chromosome break (q) is calculated to be 0.79.     

Cryopreservation effects on sperm function and fertility in two threatened crane species

The capacity to cryopreserve semen from captive cranes facilitates production of offspring from behaviorally incompatible or geographically separated pairs, and allows for long-term preservation of valuable genetic materials. The present study sought to develop effective cryopreservation protocols for whooping (Grus americana) and white-naped (Grus vipio) cranes, through examining the influences of two permeating (DMA and Me₂SO) and one non-permeating (sucrose) cryoprotectants, as well as vitamin E on post-thaw sperm survival. In Study 1, ejaculates (whooping: n = 10, white-naped: n = 8) were collected and cryopreserved in one of six cryo-diluents (crane extender with: DMA; DMA+0.1M sucrose; Me₂SO; Me₂SO+0.1M sucrose; 0.1M sucrose; 0.2M sucrose) using a two-step cooling method. Frozen samples were thawed and assessed for overall motility, motion characteristics, membrane integrity, morphology, and ability to bind to the inner perivitelline membrane (IPVM). In Study 2, whooping crane ejaculates (n = 17) were frozen in crane extender containing Me₂SO alone or with vitamin E (5 μg/mL or 10 μg/mL). Frozen samples were thawed and assessed as in Study 1, except the binding assay. White-naped crane sperm were more tolerant to cryopreservation than whooping crane (15% vs 6% post-thawed motility). In both species, sperm cryopreserved in medium containing Me₂SO alone displayed higher post thaw survival and ability to bind to IPVM than the other cryodiluent treatments. Vitamin E supplementation exerted no benefits to post thaw motility or membrane integrity. The findings demonstrated that there was species specificity in the susceptibility to cryopreservation. Nevertheless, Me₂SO was a preferred cryoprotectant for sperm from both whooping and white-naped cranes.     

Cytogenetic effects of cyclophosphamide on mouse spermatogonia.

NMRI mice were treated with single doses of cyclophosphamide (Cytoxan) and spermatogonia were analysed for chromosome aberrations at various time intervals after treatment. The maxima of aberrations were found 24 hrs p.i. Chromatid type aberrations were observed exclusively. About half of the aberrations consisted of chromatid interchanges, 92% of which exchanging short arm fragments close to the centromeric region. The lack of meiotic multivalents in diakinesis-metaphase I after treatment of spermatogonia stem cells with cyclophosphamide in the study of Leonard and Linden (1972) is discussed.     

华南地区3种入侵植物与本地植物叶片建成成本的比较

生物量建成成本作为衡量植物生物量建成所需能量的指标, 反映了植物的能量利用策略, 较低的建成成本可能会增加入侵种的竞争优势。本研究以华南地区3种危害严重的入侵植物薇甘菊(Mikania micrantha)、三裂叶蟛蜞菊(Wedelia trilobata)和五爪金龙(Ipomoea cairica)为研究对象, 选取与它们伴生或近缘的本地植物鸡矢藤(Paederia scandens)、蟛蜞菊(W. chinensis)和厚藤(I. pescaprae)作为对照, 比较了相同环境下培养的入侵植物和本地植物叶片建成成本的差异。结果表明, 这3种入侵植物的叶片单位质量建成成本(CCmass)和单位面积建成成本(CCarea)均低于它们的本地对照种。将3种入侵植物作为一组, 它们的叶片平均CCmass (1.17 g glucose/g)和CCarea (22.34 g glucose/m2)显著低于本地种的叶片平均CCmass (1.32 g glucose/g)和CCarea (36.93 g glucose/m2)。本研究结果进一步证实, 入侵植物与本地植物相比具有较低的叶片建成成本, 这可能是它们入侵成功的原因之一。同时, 本研究通过分析叶片建成成本与叶片碳浓度、氮浓度、灰分含量(Ash)以及去灰分热值(Hc)的相互关系, 探讨了影响入侵种和本地种叶片建成成本的可能因素。结果显示, 入侵植物具有较低的叶片建成成本是与其较低的碳浓度和氮浓度以及较高的灰分含量相联系的。     

Fine structure of spermatogonia and primary spermatocytes in rabbits

Summary The fine structure of rabbit Spermatogonia and primary spermatocytes in meiotic prophase has been studied with different methods of preparation, including a technique for acid phosphatase activity. The spermatogonial cytoplasm is rich in free ribosomes and containes moderate amounts of vesicular, smooth-surfaced endoplasmic reticulum and mitochondria, a simple Golgi-apparatus, some micropinocytotic vesicles, and occasional multivesicular bodies, vacuoles and dense bodies with acid phosphatase activity. The large type A Spermatogonia have a prominent nucleolus and their mitochondria sometimes form clusters with a dense intermitochondrial substance, similar to that in spermatocytes.The nucleus and cytoplasm of primary spermatocytes increase markedly in volume and density during meiotic prophase. The Golgi apparatus enlarges and becomes more differentiated and finally forms small proacrosome granules. The endoplasmic reticulum produces numerous small, mainly smooth vesicles and might also be the source of a new organelle: numerous piles of narrow cisternae with opaque contents. These piles disintegrate late in prophase. The mitochondria become aggregated in clusters with dense intermitochondrial substance and their internal structure is characterized by highly dilated cristae and small particles, interpreted as mitochondrial ribosomes, in the matrix. The role of these structures in the formation of new mitochondria is discussed. The clusters of mitochondria finally disperse and their cores of dense intermitochondrial substance, possibly containing ribonucleoprotein, coalesce into a large chromatoid body similar to that in spermatids. Micropinocytosis and a few lysosomes occur in most spermatocytes. The pachytene nuclei show prominent nucleoli and a distinct sex vesicle without any synaptinemal complex.The importance for spermatid differentiation of some events taking place in the cytoplasm of primary spermatocytes is emphasized.Financial support for this study was received from the Swedish Medical Research Council.     

Comparison of the fine-scale genetic structure of three dipterocarp species

We investigated the fine-scale genetic structure of three tropical-rainforest trees, Hopea dryobalanoides, Shorea parvifolia and S. acuminata (Dipterocarpaceae), in Peninsular Malaysia, all of which cooccurred within a 6-ha plot in Pasoh Forest Reserve. A significant genetic structure was found in H. dryobalanoides, weaker (but still significant) genetic structure in S. parvifolia and nonsignificant structure in S. acuminata. Seeds of all three species are wind dispersed, and their flowers are thought to be insect pollinated. The most obvious difference among these species is their height: S. parvifolia and S. acuminata are canopy species, whereas H. dryobalanoides is a subcanopy species. Clear differences were also found among these species in their range of seed dispersal, which depends on the height of the release point; so taller trees disperse their seed more extensively. The estimates of seed dispersal area were consistent with the degree of genetic structure found in the three species. Therefore, tree height probably had a strong influence on the fine-scale genetic structure of the three species.     

Spermiogenesis and the ultrastructure of mature sperm in Eurygaster intergriceps

An electron-microscope study of spermiogenesis and the ultrastructure of mature sperm was made on Eurygaster integriceps. During spermiogenesis, a manchette consisting of two large groups of microtubules and an unusual centriolar adjunct are formed. The latter looks like two half cylinders located almost at right angles to one another. Its wall consists of several dark layers divided by lighter areas. The centriole and its adjunct are not identified in the mature sperm. Bug spermatids have a large amount of amorphous pericentriolar matter, which assists in establishing an unusual nuclear pattern. The mature sperm is distinguished by a number of unique features. Its nucleus consists of three interconnected parts: the inner and outer cylinders and a part freely suspended along the middle piece. The intranuclear channel is blindly closed at the apical end and filled with dark amorphous matter that originates from the pericentriolar matter. The acrosome has an extracellular part resembling a diagonally striated rod, which is sometimes disengaged from its surface. The axoneme has 9+9(2) + 2 tubules. It is connected with the Nebenkern by dark arms.     

Comparison of imposex response in three Prosobranch species

A comparative study of the three gastropod species Nucella lapillus (L.), Ocenebra erinacea (L.) and Hinia (Nassarius) reticulata (L.) reveals that Nucella is the most TBT sensitive species while Hinia is the least sensitive. Of the two imposex indices VDSI and RPSI, good interspecies correlations were obtained only for VDSI. The three species can be considered as complementary not only in terms of their ecology but also for their levels of sensitivity. Indeed, Nucella and Ocenebra are useful test species at TBT concentrations below 2 ng Sn 1⁻¹ while Hinia is the more appropriate species at higher TBT levels. For the first time, two sterilised Hinia females are recorded. This sterilization does not seem to be due to proliferation of vas deferens tissue in the vaginal opening and further investigation is needed to find intermediary VDS stages between stage 4⁺ and sterilization. Studies using Nucella show that the use of narcotization in imposex analysis leads to an underestimation of RPSI compared with non-narcotization methods. Indeed, narcotization straightens the penis and increases its length when compared with non-narcotized animals, but this increase is proportionally higher in males than in females.     

Comparison of the effects of irradiation and splenectomy on Babesia rodhaini infection in mice

Comparison of the effects of irradiation and splenectomy on Babesia rodhaini infection in mice. International journal for Parasitology3: 773–781. Babesia rodhaini infection was compared in irradiated, splenectomized and control mice. Although irradiation reduced the weight of the spleen by as much as 95 per cent, this reduction in size did not result in parasitaemia levels comparable to those seen in splenectomized mice, which were consistently higher. Parasitaemias were similar in irradiated and control mice, but the mean survival time in control mice was longer than that of irradiated or splenectomized mice, which were comparable. Splenectomy generally resulted in higher parasitaemias than those seen in non-splenectomized mice.Since B. rodhaini has a predeliction for invading reticulocytes, the apparent failure of irradiated mice to develop parasitaemias comparable to those of splenectomized mice, may have been due to the selective destruction of these immature red cells by irradiation.     

重金属铜对3种跳虫的影响

为选择适于国内土壤环境健康测试的跳虫物种,采用重金属食物投入法,比较分析了重金属铜对3种跳虫的影响,结果表明：3种跳虫中似少刺齿姚（Homidia similis）敏感性最强;小原等节姚（Proisotoma minuta）耐受性最强;紫女兆（Ceratophysella duplicispinosa）的敏感性和耐受性均位于二者之间。低浓度的铜能促进3种跳虫的生长和繁殖。与以往相关研究结果比较显示。小原等节虫兆较以前认为的最具耐受性物种——环带长角长姓（Orchesella cincta）有更好的耐受性．为研究跳虫耐受机制的一种好材料。而刺齿姚类则可能是土壤环境健康状况的敏感指示生物。     

三种白蚁的头胸部及消化道结构特征比较

【目的】白蚁具有降解木质纤维素的能力,主要场所在消化道内,因此消化道形态结构的研究具有重要意义。【方法】本文对采自河南省的3种白蚁(平额散白蚁Reticulitermes planifrons Li et Ping、湖南散白蚁Reticulitermes hunanensis Tsai et Peng和双工土白蚁Odontotermes dimorphus Li et Xiao的兵蚁和工蚁头胸部特征及其消化道结构进行了比较。【结果】两种散白蚁兵蚁的头壳、后颏和上颚没有明显差异,但与双工土白蚁差异显著。3种白蚁工蚁的前肠、后肠及消化道平均长度均大于兵蚁,且差异显著(P<0.05),而中肠的差异不显著;双工土白蚁的肠道总长度工蚁/兵蚁比值(1.4倍)大于两种散白蚁(1.1倍);除了嗉囊和囊形胃外,两种散白蚁工蚁的其余消化道各段差异显著(P<0.05),与双工土白蚁相比差异也显著。【结论】工蚁的消化道比兵蚁发达,散白蚁的消化道结构与土白蚁有较大不同,这些结果与工蚁和兵蚁的社会分工有关,同时也表明高等白蚁与低等白蚁相比不仅是采食习惯的差别,自身消化系统结构与分区也有较大不同,并为白蚁的生物防治和生物质资源利用提供了资料。     

Dietary specialization and the effects of plant species on potential multitrophic interactions of three species of nymphaline caterpillars

The diet breadth of insect herbivores influences their response to variation in plant quality, and these bitrophic interactions have implications for the higher‐level trophic interactions between herbivores and their natural enemies. In this comparative study, we examined the role of host plant species and plant secondary chemistry on the potential interactions between three species of nymphaline caterpillars and their natural enemies. The caterpillar species (all Lepidoptera: Nymphalidae) varied in their degree of specialization: the buckeye, Junonia coenia Hübner, is a specialist on plants that contain iridoid glycosides (IGs); the white peacock, Anartia jatrophae L., feeds on plants in five families, some of which contain IGs and some of which do not; and the painted lady, Vanessa cardui L., is a generalist, feeding on plants in at least 15 families. Each species was reared on leaves of an introduced host plant, Plantago lanceolata L. (Plantaginaceae), which produces two IGs, aucubin and catalpol, and on another plant species that is a common host plant. These alternate host plants were Plantago major L. (Plantaginaceae) for J. coenia, Bacopa monnieri (L.) Pennell (Plantaginaceae) for A. jatrophae, and Malva parviflora L. (Malvaceae) for V. cardui. We examined growth, sequestration, and immune response of these caterpillars on the different host plant species. Junonia coenia developed more rapidly and sequestered higher IG concentrations when reared on P. lanceolata, whereas both other species grew more slowly on P. lanceolata. Host plant did not influence immune response of J. coenia or A. jatrophae, whereas V. cardui immune response was weaker when reared on P. lanceolata. Junonia coenia was most efficient at IG sequestration and A. jatrophae was least efficient, when all three species were reared on P. lanceolata. These results indicate that diet breadth may play an important role in structuring tritrophic interactions, and this role should be further explored.