The pattern of the follicle cell diversification in ovarian follicles of the true fruit flies, Tephritidae.

In flies (Diptera), the ovary displays several distinct patterns of the follicular epithelium formation and diversification. Two main patterns have been identified in the true flies or Brachycera, namely the Rhagio type and the Drosophila type. These patterns align with the traditional division of Brachycera into Orthorrhapha and Cyclorrhapha.

ESCRT-III-dependent adhesive and mechanical changes are triggered by a mechanism detecting alteration of septate junction integrity in epithelial cells.

Barrier functions of proliferative epithelia are constantly challenged by mechanical and chemical constraints. How epithelia respond to and cope with disturbances of barrier functions to allow tissue integrity maintenance is poorly characterised. Cellular junctions play an important role in this process and intracellular traffic contribute to their homeostasis.

Evolutionary origin and functioning of pregenital abdominal outgrowths in a viviparous insect, Arixenia esau.

Although pregenital abdominal outgrowths occur only rarely in pterygote insects, they are interesting from the evolutionary viewpoint because of their potential homology to wings. Our previous studies of early development of an epizoic dermapteran, Arixenia esau revealed that abdominal segments of the advanced embryos and larvae, growing inside a mother's uterus, are equipped with paired serial outgrowths. Here, we focus on the origin and functioning of these outgrowths.

Viviparity in Two Closely Related Epizoic Dermapterans Relies on Disparate Modifications of Reproductive Systems and Embryogenesis.

Nutritional modes operating during embryonic/larval development of viviparous species range from "pure" lecitothrophy in which embryos rely solely on reserve materials (yolk spheres, lipid droplets, and glycogen particles) accumulated in the egg cytoplasm to matrotrophy in which embryos are continuously supplied with nutrients from a parental organism. Interestingly, a wide spectrum of diverse "mixed" modes employed in the embryo nourishment have also been described among viviparous species. Here, we summarize results of histochemical, ultrastructural, and biochemical analyses of reproductive systems as well as developing embryos of two closely related viviparous species of earwigs (Dermaptera), Hemimerus talpoides and Arixenia esau.

Viviparity in the dermapteran Arixenia esau: respiration inside mother's body requires both maternal and larval contribution.

Earwigs (Dermaptera) use different strategies to increase their reproductive success. Most species lay eggs; however, viviparity of the matrotrophic type has been reported in two groups: Hemimeridae and Arixeniidae. In Arixeniidae, offspring develop in two separate places: inside an ovary (the intraovarian phase) and within a uterus (the intrauterine phase).

Organelle assemblages implicated in the transfer of oocyte components to the embryo: an insect perspective.

Besides reserve materials (yolk spheres, lipid droplets), ribosomes and various mRNA species, insect oocytes contain large easily morphologically recognizable organelle assemblages: the Balbiani body and the oosome (pole plasm). These assemblages are implicated in the transfer of oocyte components (mitochondria, polar granules) to the embryo that is to offspring. Here, we review present knowledge of morphology, morphogenesis, molecular composition and function/s of these assemblages.

Excretion in the mother's body: modifications of the larval excretory system in the viviparous dermapteran, Arixenia esau.

The vast majority of Dermaptera are free-living and oviparous, i.e., females lay eggs within which embryonic development occurs until the larva hatches.

Unusual morphological adaptations and processes associated with viviparity in an epizoic dermapteran.

Matrotrophic viviparity is a reproductive pattern in which offspring develop inside a female's body which provides gas exchange and nutrients necessary for development. Besides placental mammals, structural and physiological aspects of matrotrophic viviparity are poorly characterized. In insects, the majority of species is oviparous, i.

The Pole (Germ) Plasm in Insect Oocytes.

Animal germline cells are specified either through zygotic induction or cytoplasmic inheritance. Zygotic induction takes place in mid- or late embryogenesis and requires cell-to-cell signaling leading to the acquisition of germline fate de novo. In contrast, cytoplasmic inheritance involves formation of a specific, asymmetrically localized oocyte region, termed the germ (pole) plasm.

The ovary structure and oogenesis in the basal crustaceans and hexapods. Possible phylogenetic significance.

Recent large-scale phylogenetic analyses of exclusively molecular or combined molecular and morphological characters support a close relationship between Crustacea and Hexapoda. The growing consensus on this phylogenetic link is reflected in uniting both taxa under the name Pancrustacea or Tetraconata. Several recent molecular phylogenies have also indicated that the monophyletic hexapods should be nested within paraphyletic crustaceans.

Ultrastructural analysis of the ovary and oogenesis in Spinicaudata and Laevicaudata (Branchiopoda) and its phylogenetic implications.

Recent molecular studies have indicated a close relationship between Crustacea and Hexapoda and postulated their unification into the Pancrustacea/Tetraconata clade. Certain molecular analyses have also suggested that the crustacean lineage, which includes the Branchiopoda, might be the sister group of Hexapoda. We test this hypothesis by analyzing the structure of the ovary and the ultrastructural features of oogenesis in two branchiopod species, Cyzicus tetracerus and Lynceus brachyurus, representing two separate orders, Spinicaudata and Laevicaudata, respectively.

Association of TCTP with centrosome and microtubules.

Translationally Controlled Tumour Protein (TCTP) associates with microtubules (MT), however, the details of this association are unknown. Here we analyze the relationship of TCTP with MTs and centrosomes in Xenopus laevis and mammalian cells using immunofluorescence, tagged TCTP expression and immunoelectron microscopy. We show that TCTP associates both with MTs and centrosomes at spindle poles when detected by species-specific antibodies and by Myc-XlTCTP expression in Xenopus and mammalian cells.

Ovary structure and early oogenesis in the remipede, Godzilliognomus frondosus (Crustacea, Remipedia): phylogenetic implications.

Remipedia are enigmatic crustaceans of uncertain phylogenetic position with the general consensus that they are crucial for understanding the crustacean/arthropod evolution. It has been demonstrated previously that the features of the ovary organization and subcellular aspects of oogenesis are useful in resolving phylogenetic relationships in arthropods such as hexapods and onychophorans. The structure of the female gonads in Remipedia remains largely unknown; therefore, we examined the gross morphology and ultrastructural details of the ovary in a remipede, Godzilliognomus frondosus, with special emphasis on characters relevant to phylogenetic reconstructions.

Nuage morphogenesis becomes more complex: two translocation pathways and two forms of nuage coexist in Drosophila germline syncytia.

We have developed a simple and reliable method of preserving antigen immunoreactivity with concomitant excellent retention of the cell ultrastructure. Using this method, we have been able to follow the origin and developmental stages of nuage accumulations within the nurse cell/oocyte syncytium in the ovary of the fruit fly, Drosophila melanogaster, at the ultrastructural level. We have found two morphologically and biochemically distinct forms of nuage material in the nurse cell cytoplasm: translocating accumulations of nuage containing the Vasa protein, termed sponge bodies and stationary polymorphic accumulations of nuage enriched in Argonaute and Survival of motor neuron proteins.

A novel pattern of follicular epithelium morphogenesis in higher dipterans.

In fly ovaries, the follicular epithelium surrounding germline cells diversifies into several morphologically distinct cell subpopulations. This complex process is crucial for the formation of a regionally complex eggshell and establishment of polarity of the future embryo. Morphogenetic changes accompanying patterning of the follicular epithelium have been best characterized in the model fly, Drosophila melanogaster.

Electron microscopy, immunostaining, cytoskeleton visualization, in situ hybridization, and three-dimensional reconstruction of Xenopus oocytes.

Although the overwhelming development of molecular techniques in recent decades has made ultrastructural studies less popular, to the point that ultrastructural interpretation is becoming a dying art, it still remains an indispensable tool for cell and developmental biologists. The introduction of EM-immunocytochemistry and three-dimensional visualization methods allows us to complement the knowledge gained from ultrastructural and molecular approaches. Because the first clues about the functions of newly discovered genes often come from the subcellular localization patterns of their proteins or RNAs, in this chapter we describe the methods that allow for precise ultrastructural localization and visualization of protein and RNA molecules within the compartments, organelles, and cytoskeleton of Xenopus oocytes.

Diversification of follicular cells in the ovaries of the horse fly Haematopota italica (Diptera: Tabanidae). Similarities and differences with the Drosophila model system.

In insect ovaries, germ line cells are surrounded by somatic cells that initially form a uniform follicular epithelium. The subsequent diversification of the follicular cells into several subpopulations enables specification of distinct structures in different regions of complex eggshells. It also influences the patterning of the future embryo.

Structure of the ovaries and follicular epithelium morphogenesis in Drosophila and its kin.

In insects, the ovarian follicular epithelium morphogenesis has been intensively studied and best characterized in the fruit fly, Drosophila melanogaster. It is well established that initially identical somatic follicular cells (FCs) form a simple epithelium overlying the germline cells, but during oogenesis, they diversify into a number of morphologically distinct subpopulations each responsible for creating specific eggshell structures. In addition, some FC subpopulations (e.

Accessory nuclei in insect oogenesis: in search of the function of enigmatic organelles.

This review compiles present knowledge of the structure and molecular composition of the enigmatic cytoplasmic organelles called accessory nuclei. Most typically, they are found in the perinuclear cytoplasm in oocytes of insects and several other invertebrates. Accessory nuclei originate by budding of the oocyte nucleus (germinal vesicle) and are surrounded by an envelope identical to the nuclear envelope.

Stanislaw Smreczynskis legacy and the Department of Zoology of the Jagiellonian University of Krakow (Poland).

This article covers the origin and development of scientific interest in insect and amphibian developmental biology at the Department of Systematic Zoology and Zoogeography of the Jagiellonian University. The greater part of this historical account is devoted to Professor Stanislaw Smreczynski (1899-1975), the founding father of the Department, and comments on his biography and research achievements in the field of animal experimental embryology. A particular emphasis is on Smreczynski's contributions to contemporary understanding of early embryonic development of amphibians and insects as well as his expertise in Pleistocene and extant weevils (Curculionidae).

Oogenesis in phthirapterans (Insecta: Phthiraptera). I. Morphological and histochemical characterization of the oocyte nucleus and its inclusions.

We characterize morphological and histochemical changes occurring within the oocyte nucleus (germinal vesicle) during oogenesis in two phthirapteran species: the pig louse, Haematopinus suis (Anoplura) and the pigeon louse, Columbicola columbae (Mallophaga). In previtellogenic oocytes, within the oocyte nucleus the chromatin condenses and forms the karyosome. In contact with the karyosome numerous dense and highly heterogeneous nuclear bodies occur.

Assembly and breakdown of Cajal bodies in accessory nuclei of Hymenoptera.

In some species of insects, oocytes have vesicular organelles, termed accessory nuclei (ANs). The ANs form by budding off from the nuclear envelope of the oocyte and are filled with translucent matrix containing dense inclusions. One type of these inclusions contains coilin and small nuclear ribonucleoproteins (snRNPs) and is homologous to Cajal bodies.

Sm proteins, the constituents of the spliceosome, are components of nuage and mitochondrial cement in Xenopus oocytes.

A conserved feature of germ cells in many animal species is the presence of perinuclear electron-dense material called the "nuage" that is believed to be a precursor of germinal (or polar or P) granules. In Xenopus oogenesis the nuage is first observed near the nuclear envelope and subsequently in close contact with mitochondria, at which stage it is called the mitochondrial cement. In this study, we found that, in Xenopus pre-stage I and stage I oocytes, nuage and mitochondrial cement contain the spliceosomal Sm proteins, Xcat2 mRNA, and DEAD-box RNA helicase XVLG1.

snRNPs are present in the karyosome capsule in the weevil germinal vesicle.

Within the oocyte nucleus of the apple blossom weevil, Anthonomus pomorum (Insecta, Coleoptera) highly condensed and transcriptionaly inactive chromosomes form the karyosome. During its formation, within the nucleoplasm numerous, variably sized spherical inclusions termed nuclear bodies occur. As oogenesis progresses, the karyosome is gradually surrounded by a prominent sheath, the karyosome capsule.

The Balbiani body and generation of early asymmetry in the oocyte of a tiger beetle.

The developmental changes within the Balbiani body in previtellogenic and early vitellogenic oocytes of a tiger beetle, Pseudoxycheila angustata, are described. Our study showed that the Balbiani body forms in a juxtanuclear position in previtellogenic oocytes. Subsequently, it disperses within the ooplasm while multivesicular bodies, a prominent component of the Balbiani body in this species, segregate out and are targeted to the posterior pole of the oocyte.