Pathogenic ability and saline stress tolerance of two Fusarium isolates from Odontesthes bonariensis eggs

BackgroundSeveral fungal species represent a potential risk to embryos of Odontesthes bonariensis (Cuvier and Valenciennes, 1835), a euryhaline freshwater fish that lives in the Pampean inland waters and has potential economic relevance.AimsTo identify two fungi isolated from O. bonariensis eggs exposed to saline conditions and to characterize their pathogenicity and tolerance to sodium chloride solutions.MethodsThe isolates were identified by morphological features, and a preliminar phylogenetic analysis using sequences of translation elongation factor 1-alpha (EF-1α) and calmodulin (CAM) was performed. Koch's postulates were tested to identify the causative agent of fungal infection. The influence of NaCl on the fungal growth was evaluated in in vitro assays.ResultsThe isolates LPSC 1001 and 1002 were identified as representatives of the genus Fusarium, and belonging to the Fusarium incarnatum-Fusarium equiseti species complex (FIESC) and the Fusarium solani species complex (FSSC), respectively. Histological observations on eggs exposed in vitro to both isolates in infectivity assays confirmed the ability of the fungal isolates to penetrate to egg's chorionic membrane, leading to the death of embryos. Increasing NaCl concentration in the culture medium reduced the growth of the isolates LPSC 1001 and 1002, being completely inhibited at 160 and 120 g/l NaCl respectively.ConclusionsThe isolates LPSC 1001 (FIESC) and 1002 (FSSC) were identified as fungal pathogens to O. bonariensis eggs. The use of NaCl solutions as antifungal treatment was not effective to control the infection with these strains.     

Structure and function of the hydropyle of the egg of the bug, Sphaerodema molestum

Changes in the wet weight, dry weight, and volume of the egg of Sphaerodema molestum during embryonic development have been studied. Also, experiments have been carried out to ascertain the route of entry of water from the environment into the egg.During development the eggs considerably increase their volume and wet weight while their dry weight progressively decreases. When the eggs of S. molestum are incubated in dye solutions, the latter penetrate through the chorionic hydropyle and reach the outer surface of the serosal hydropyle. This indicates that water enters in significant quantity through the chorionic and serosal hydropyles. The behaviour of 48-hr-old experimental eggs of S. molestum, in which the entry of water is blocked, further confirms that the intake of water is effected only through the hydropyles. The significance of the uptake of water in the eggs is discussed in relation to protein metabolism during embryogenesis.     

Nutritive Egg Formation in the Marine Snails Crepidula dilatata and Nucella crassilabrum

Summary

Both frequency and morphology of the nutritive eggs in the snails Crepidula dilatata and Nucella crassilabrum were analyzed. In both species, nutritive eggs constitute over 90% of the eggs deposited in each capsule. Marked differences in nutritive eggs exist between these species with respect to morphological and cytological characteristics.

Nutritive eggs of C. dilatata remain uncleaved and in their cytological characteristics resemble oocytes whose development becomes arrested at the stage of germinal vesicle. Although the eggs of this snail are dimorphic in size, such dimorphism is not correlated with the fate of these cells. Nutritive eggs of N. crassilabrum typically abort their development at the stage of zygote cleavage divisions and anarchic cleavage occurs only in a small fraction of them (X = 5–6%).

The nature of these food eggs is discussed. Our findings suggest that, at least in C. dilatata, the mechanisms of nutritive egg formation reside in properties of the oocyte.     

Introductory class exercises in experimental embryology using Xenopus laevis

Abstract

This paper describes classical experiments of experimental embryology which may be repeated at class level using the early embryos of Xenopus laevis. The experiments demonstrate the effects of lithium on the early development of the nervous system, and the use of hypertonic salt solutions to produce exogastrulation. Both experiments involve the removal of the jelly coats around the embryo, and for this purpose a rapid chemical method using a cysteine hydrochloride/papain solution is described. Both experiments are theoretically important: the effects of lithium are used as evidence for the existence of an anterior-posterior gradient in the early embryo, while exogastrulation provides a convenient system for interfering with the primary inductive effect of the chordo-mesoderm, necessary for ectodermal neuralization.

The procedure for obtaining fertile eggs from mature Xenopus specimens by injection of mammalian chorionic gonadotrophin is described.     

Nocturnal parasitism of moth eggs by Trichogramma wasps

Parasitoid wasps of the genus Trichogramma are used worldwide as biological control agents against lepidopteran pests. Trichogramma wasps develop inside eggs of a wide range of host species, most of them moths. They are generally considered as diurnal insects. Here, we investigated whether Trichogramma wasps can also successfully parasitise host eggs at night under controlled laboratory conditions. Eggs of the moth Ephestia kuehniella were offered under dark conditions (scotophase) to females of Trichogramma brassicae and Trichogramma evanescens either from 9:00 PM to 9:00 AM or from 11:00 AM to 5:00 PM at four different temperatures (5°C, 10°C, 15°C and 20°C). Both species are known to parasitise E. kuehniella eggs in the photophase during daytime. The results show that T. brassicae did not parasitise eggs in the scotophase at night and only very few in the artificially induced scotophase during daytime from 10°C to 20°C. In contrast, T. evanescens parasitised more eggs in the dark both at night and artificially induced scotophase during daytime. Parasitism in the scotophase already started at 5°C, with more eggs being parasitised and more offspring being produced at higher temperatures. T. evanescens displayed higher parasitism activity in the induced scotophase during daytime than in the scotophase at night. The present study suggests that Trichogramma are capable of successfully parasitising host eggs at night, even at low temperatures, but that nocturnal activity with respect to parasitism varies between wasp species.     

No brood parasitism by the Great Spotted Cuckoo Clamator glandarius on the Azure-winged Magpie Cyanopica cyanus

Capsule No case of parasitic interaction was found after 12 years of intensive monitoring of a marked population in Spain where both species are sympatric.

Aims To evaluate whether the Azure-winged Magpie is parasitized, and suggest possible causes that affect its relationship with the Great Spotted Cuckoo.

Methods Data from a long-term field study of marked individuals in a population of Azure-winged Magpie in Spain, were collected from about 60 nests per year over 12 years.

Results Although common in the area, no eggs or young of the Great Spotted Cuckoo were found in an Azure-winged Magpie nest.

Conclusion The Great Spotted Cuckoo does not appear to parasitize the Azure-winged Magpie, and we suggest that elevated predation rates on nests may be an important, overlooked factor potentially affecting the choice of host species by this brood parasite.     

椰子木蛾的产卵节律及其对寄主植物的产卵选择性

【背景】椰子木蛾是近年来新入侵我国棕榈科植物的害虫,研究其产卵习性可为监测和防治该虫提供参考。【方法】在室内条件下,观察、记录了椰子木蛾雌成虫的产卵节律及其对不同寄主植物的产卵选择性。【结果】椰子木蛾最高日产卵量可达34.4粒·头-1,且主要集中在羽化后4 d内产卵,占总产卵量的54.1%;产卵活动主要发生在夜间23:00到次日8:00;在椰子、蒲葵、大王棕、槟榔和散尾葵等寄主植物上的产卵量无显著差异,为89.3~147.7粒·头-1,但产卵位置存在差别。【结论与意义】椰子木蛾雌成虫具有较强的繁殖能力和产卵节律性,且在不同寄主植物上的产卵量一致。     

Osmotrophy in fossil protoctists and early animals

Summary

The role of Ca²⁺ in activation and early development of locust eggs was examined through measurement of ooplasmic Ca²⁺ levels before and after fertilization, and through experimental activation of unfertilized eggs. Ooplasmic pCa (i.e. the negative logarithm of Ca²⁺ activity) measured in intact eggs decreased from 5.35 before fertilization, to 4.77 and 3.00 by 1 day and 3 days after fertilization, respectively. pCa was also determined for samples of ooplasm collected by rupturing eggs under paraffin oil. The pCa was 5.10 in ooplasm isolated from unfertilized eggs, and 3.84 in ooplasm collected from eggs within 4 h of fertilization. Ooplasmic pCa remained between 3.97 and 3.12 from 1–6 days after fertilization. Since a decline in pCa indicates an increase in ooplasmic Ca²⁺ activity, the data suggest that regulation of ooplasmic Ca²⁺ during post-fertilization development involves release of Ca²⁺ from internal stores. Experimental egg activation was examined in eggs dissected from the oviducts before fertilization and incubated on moist filter paper. Some eggs were first immersed in experimental solutions for 30–60 minutes before incubation. The presence of an embryo 2 or 4 days after fertilization or experimental treatment was used as an indicator of egg activation. Activation occurred in 92% and 12% of fertilized and untreated eggs, respectively. The percentage of unfertilized eggs which activated increased to 47% if eggs were soaked 30–60 minutes in physiological saline, and to as much as 65%-68% if eggs were injected with Ca²⁺ buffers or if a Ca²⁺ action potential was evoked. Up to 36% and 42% of unfertilized eggs activated after incubation in Ca²⁺-free salines or in the presence of the Ca²⁺-channel blocker Cd²⁺, respectively. Taken together, the results suggest that entry of external Ca²⁺ through voltage dependent channels increases the proportion of eggs which activate, but is not an absolute requirement for activation.     

Developmental potential of LT/Sv parthenotes derived from oocytes matured in vivo and in vitro

Release of oocytes of LT/Sv mice from the meiosis-inhibiting influence of antral follicles promotes parthenogenetic activation and development to early cleavage stages of 14% of the eggs. However, to attain the potential to develop to blastocysts under the culture conditions used, the oocytes must mature within follicles for 8–9 hr after human chorionic gonadotropin (HCG) administration. The results suggest that some positive influence, which does not occur during spontaneous oocyte maturation under defined conditions in vitro, occurs within preovulatory follicles and imparts developmental competence to the maturing oocytes.     

Salt soluble without jelly-like component from the oviducal gland induces chorionic expansion in the ova of the Japanese common squid Todarodes pacificus

Abstract

In vitro fertilization of squid requires the jelly substance found in the female oviducal gland; yet, the active component of this substance that facilitates fertilization remains unknown. Here, we used biochemical methods to separate the jelly substance of Todarodes pacificus (Oegopsida) and Sepioteuthis lessoniana (Myopsida family) into four fractions; specifically, two water soluble fractions (Molecular weight > 10,000 and < 10,000), one salt soluble fraction, and one insoluble fraction. The salt soluble fraction of T. pacificus induced chorionic expansion (perivitelline space formation), which precedes the normal embryonic development of ova. In contrast, the salt soluble fraction of S. lessoniana elicited insufficient expansion of the ova, only producing embryos with high abnormality rates. These results suggest that the salt soluble component(s) (not the jelly-like substances) in the oviducal gland induce chorionic expansion and hatching in Oegopsida, and that these components may be similar in Myopsida.     

Morphology of the egg shell and the developing embryo of the Red Palm Weevil,Rhynchophorus ferrugineus (Oliver)

The harvested eggs of Rhynchophorus ferrugineus are ovo-cylindrical shaped, averaged 1.09 mm in length and 0.43 mm in width, with ratio of L\W 4.42. The chorionic layer of electron dense material is seen covering the exochorion structure of the eggs. The egg main body chorion exhibits a polygonal pattern and architecture surface of the egg is supported by a system of irregular interconnecting grooves. The micropylar apparatus of the eggs of the Red Palm Weevil, R. ferrugineus is described in the present study for the first time. Two micropylar openings are found closed to the center of the posterior wide pole of the egg. Each micropylar opening presents a single small orifice and its surrounding chorion is porous and densely set with tiny projections allowing the spermatozoa to penetrate the egg. Respiratory aeropyles are distributed on the borders of reticulations in the area chorionic surface of egg capsule. The hatching region is detected on the anterior part at the opposite side of the egg. Changes in the appearance and shape of R. ferrugineus eggs as well as the incidence of embryonic development are observed.     

Egg envelopes of Baetis rhodani and Cloeon dipterum (Ephemeroptera, Baetidae): a comparative analysis between an oviparous and an ovoviviparous species

A comparative ultrastructural investigation on the eggshell (vitelline and chorionic envelopes) has been carried out in the nymphs of two mayfly species encompassed into the Baetidae, namely Baetis rhodani and Cloeon dipterum. During oocyte differentiation in the meroistic telotrophic ovarioles, gametes are connected to discrete nurse cells by trophic cords. In B. rhodani, each ovariole contains several eggs arranged in sequence, whereas in C. dipterum each contains a single egg. Follicle cells are competent for vitelline and chorionic envelope synthesis. Baetis rhodani is an oviparous species and the chorion is fairly thick, formed by an alveolate endochorion and a fibrillar exochorion delimited by a honey‐comb roof. Cloeon dipterum stands out among Ephemeroptera for being ovoviviparous. In B. rhodani, ovulation starts in the older nymphs with dark wing‐pads, whereas in C. dipterum choriogenesis ends in the imaginal stage. Here the chorion is very thin and laid eggs hatch almost immediately, allowing the larvulae to move out. The maturation of a single egg per ovariole is synchronized with the achievement of the adult stage. The acquisition of ovoviviparity has led to remarkable changes in the ovariole organization along with a simplification of the eggshell structure.     

Fungal ovicidal activity on Toxocara canis eggs

BackgroundVisceral toxocariasis is a parasitic zoonosis caused by Toxocara canis. The prevalence of this parasite in dogs, soil contamination and the resistance of eggs increase human exposure to the disease. Moreover, the difficulties of the control measures justify the need for alternative ones.AimsThe objective of this study was to evaluate the in vitro ovicidal activity of fungi isolated from soils from public places in the city of Pelotas, Rio Grande do Sul, Brazil, on Toxocara canis.MethodsSamples of soil from ten localities were inoculated onto Petri dishes with 2% water–agar (WA) that contained antibiotics, and incubated at 25 °C/21 days. Isolated fungi were tested in vitro for ovicidal activity, with five replicates. One mL of an embryonated Toxocara canis egg suspension (10³ eggs) was poured over the fungal cultures after 10 days of growth. At intervals of 7, 14 and 21 days, 100 eggs were removed from each plaque and evaluated by optical microscopy.ResultsAcremonium, Aspergillus, Bipolaris, Fusarium, Gliocladium, Mucor and Trichoderma were isolated from the soil. A significant ovicidal type 3 effect was observed in Trichoderma, Fusarium solani complex and Acremonium. Those isolates from the genus Trichoderma showed their ovicidal effect on the 14th day of fungus–egg interaction. The other fungal genera tested showed a type 2 effect.ConclusionsThese results suggest that the use of Trichoderma and Fusarium solani complex in biological control of T. canis is promising; however, further studies should be performed.     

人脐带间充质干细胞条件培养基联合白藜芦醇对人滋养层细胞的作用

目的:探讨人脐带间充质干细胞条件培养基联合白藜芦醇对人绒毛膜外滋养层细胞凋亡的影响。方法:通过CCK8细胞活力检测试剂盒测定白藜芦醇及其与人脐带间充质干细胞条件培养基共同处理人绒毛膜外滋养层细胞HTR8后对细胞增殖及活性的影响;细胞迁移试验检测白藜芦醇和人脐带间充质干细胞条件培养基对细胞迁移能力的影响;显微镜观察细胞形态,并用流式细胞仪检测细胞凋亡率的变化;Western blot检测白藜芦醇和人脐带间充质干细胞条件培养基对细胞凋亡相关蛋白Bax、Bcl-2以及迁移相关蛋白MMP-9表达的影响。结果:白藜芦醇能够抑制HTR8细胞增殖,抑制细胞迁移及MMP-9蛋白的表达,改变Bax和Bcl-2蛋白表达诱导细胞凋亡的作用。而人脐带间充质干细胞条件培养基能够逆转白藜芦醇对细胞的抑制作用。结论:人脐带间充质干细胞条件培养基能够通过调控Bax、Bcl-2、MMP-9的蛋白表达逆转白藜芦醇对人绒毛膜外滋养层细胞的抑制作用。人脐带间充质干细胞条件培养基可作为潜在的治疗人绒毛膜外滋养层细胞功能障碍的临床手段,孕妇需要小心使用白藜芦醇。     

Morphology of eggs and spermatheca of <Emphasis Type="Italic">Odontotarsus purpureolineatus</Emphasis> (Heteroptera,Scutelleridae)

The morphology of the spermatheca and eggs of Odontotarsus purpureolineatus were studied by optical microscopy and scanning electron microscopy. The spherical eggs were about 1.35 mm long and 1.09 mm wide. The egg batches generally consist of 13–14 eggs. The egg surface is covered by polygonal (hexagonal and pentagonal shapes prevail) ridges and tiny chorionic tubercles. There were 8–10 aero-micropylar processes between the polygons. The spermatheca of O. purpureolineatus is characterized by a spherical spermathecal bulb, a pumping region, a flange of pump and dilation of spermathecal duct. Spermathecal processes and a median spermathecal dilation with sclerotized rod are missing. The spermathecal bulb and the pumping region possess many pores.     

Agistemus exsertus Gonzalez (Acari: Stigmaeidae) as a predator of two scale insects of the family Diaspididae (Homoptera: Diaspididae)

Abstract

The predacious mite Agistemus exsertus Gonzalez completed its life-span when fed on eggs and crawlers of the Florida red scale Chrysomphalus ficus Ashmead and the white date scale Parlatoria blanchardi (Targioni). The development was faster when individuals were maintained on eggs and crawlers of C. ficus, compared with both stages of P. blanchardi. The average number of eggs/female/day was 2.5 and 1.1 on eggs and crawlers of C. ficus, respectively. Eggs and crawlers of P. blanchardi were an unsuitable food for egg laying for A. exsertus. Life table parameters showed that A. exsertus preferred eggs of C. ficus to the crawlers as prey. The population of the predator feeding on eggs and crawlers of Florida red scale multiplied 45 and 7 times in a generation time of 23 and 20.5 days, respectively. Under these conditions, the intrinsic rate of increase (r _m) was (0.17 and 0.098) individuals/female/day on eggs and crawlers of C. ficus, while the finite rate of increase (λ) was (1.18 and 1.11) on both stages of C. ficus.     

The influence of parent body colouration and nesting habitat on bird nest predation

ABSTRACT

Capsule: Parent body colouration and nesting habitat may influence nest predation risk and, therefore, influence parental decisions on offspring care.

Aims: To investigate the adaptiveness of bird colouration under two different habitat and light conditions.

Methods: We used painted polyurethane dummies to simulate parental presence near nests, where some dummies were red, and others were cryptic brown. We placed artificial nests on trees in open and forested areas, along with two quail eggs and parental dummies.

Results: The results showed major predation on nests of the open area, however, we found no significant effect of parent colour on nest predation.

Conclusion: We suggest that the costs involved with nest site selection may overcome the costs of colouration in species that occur in these environments.     

Amphiregulin regulates the production of human chorionic gonadotropin in trophoblasts

AimsThe aim of this study was to investigate the significance of epidermal growth factor receptor (EGFR) ligands produced in syncytiotrophoblasts during normal pregnancy.Main methodsWe examined the expression of EGFR ligands in human pregnancy by real-time PCR, and analyzed the relationship between EGFR ligands and human chorionic gonadotropin (hCG) or human placental lactogen in amniotic fluid by ELISA. In addition, we also examined the EGFR ligands in syncytiotrophoblasts and the amount of hCG secretion in JAR, JEG3 and BeWo cells in the presence of each EGFR ligand.Key findingsIn order to identify possible candidates among the EGFR ligands, we examined the predominant expression of an EGFR ligand in the chorionic villi and amniotic fluid during normal pregnancy, and analyzed the relationship between EGFR ligands and hCG in trophoblastic model cells. Amphiregulin was primarily expressed throughout human pregnancy and stimulated the secretion of hCG, indicating that amphiregulin is a key molecule among EGFR ligands.SignificanceAmphiregulin may play a pivotal role in the development or maturation of placenta.     

Microanatomical diversification of the zona pellucida in aplochelioid killifishes

This study investigates zona pellucida (ZP) ultrastructure in fertilized eggs of annual killifishes (suborder Aplocheiloidei), a group of highly specialized fishes that are able to survive desiccation for several weeks to months before they hatch. Little is known about ZP or chorionic ultrastructure sustaining these life‐history modes, so scanning electron microscopy (SEM) was used to describe this trait in a large number of aplocheiloids with a focus on the family Rivulidae and the genus Hypsolebias. New images of ZP ultrastructure for 52 aplocheiloid species are provided, more than doubling the number characterized thus far. The evolution of chorionic structure within this group is studied using these new data. Characters were coded into a morphological matrix and optimized onto a consensus phylogeny to assess phylogenetic signal and reconstruct ancestral character states. Although ZP characters seem highly homoplastic and exhibit a large amount of structural convergence among lineages, aplocheiloid killifishes have evolved a number of unique structures associated with the chorion. Some annual species seem to have lost long filaments because eggs are deposited in the soil instead of being adhered to aquatic plants.     

Response of the parasitoid Telenomus podisi to induced volatiles from soybean damaged by stink bug herbivory and oviposition

Abstract

Egg parasitoids have a short time frame in which their host eggs are suitable for parasitism, and in several systems these parasitoids respond to plant volatiles induced by oviposition on the plant (either in isolation or in combination with feeding damage) as a means of finding suitable hosts. It is known that the parasitoid of pentatomid eggs Telenomus podisi responds to damage done to soybeans by female Euschistus heros, its preferred host. In this study our aim was to determine the type of E. heros damage to soybean (herbivory, oviposition or a combination of both) necessary for attraction of T. podisi. In a Y-tube olfactometer the parasitoid has shown to respond to the undamaged plant over clean air and herbivory-damaged plants over undamaged plants. However, the parasitoids did not respond to the treatments where oviposition occurred, either in isolation or in combination with herbivory. Analysis of volatile blends revealed that herbivory plus oviposition damage to soybean induced a volatile blend different to those induced when herbivory or oviposition occurred separately. These results, along with other results from this system, suggest that T. podisi uses plant volatile cues associated with female E. heros damage in order to be present when E. heros lays its eggs, and thus ensure its resource is optimal for parasitism.