Oogenesis in Crustaceans: Ultrastructural Aspects and Selected Regulating Factors

2020 ◽  
pp. 29-59
Author(s):  
Mariusz K. Jaglarz ◽  
Szczepan M. Bilinski
Keyword(s):  
Great Majority ◽  
Follicle Cells ◽  
Nurse Cells ◽  
Germline Development ◽  
Cellular Processes ◽  
Ultrastructural Studies ◽  
Large Numbers ◽  
Oocyte Cytoplasm ◽  
Germline Cells ◽  
Female Germline

This chapter explores ultrastructural aspects of crustacean oogenesis. It focuses on various cellular processes associated with female germline development in selected crustacean groups. Oogenesis in crustaceans comprises four stages: proliferation of germline cells, previtellogenesis, vitellogenesis, and formation of egg coverings. The greater part of oogenesis occurs in the ovary. In Crustacea, two structurally and functionally distinct types of ovary are recognized: panoistic and meroistic. In panoistic ovaries, all germline cells differentiate into oocytes, and this type of ovarian organization occurs in a great majority of crustaceans, including Malacostraca. In contrast, in the meroistic ovaries, oogonial cells are connected by intercellular bridges and form characteristic linear cysts. Within each cyst, only one cell becomes an oocyte, and the remaining cells differentiate into nurse cells. Meroistic ovaries are typical for Branchiopoda and Ostracoda: Podocopida. Ultrastructural studies reveal that the nucleus and cytoplasmic organelles of the oocyte are highly synthetically active in the panoistic ovary, whereas in the meroistic type, oocyte development is supported, to some extent, by accompanying nurse cells. During previtellogenesis, oocytes accumulate large numbers of various organelles, e.g. ribosomes, mitochondria, and cisternae of endoplasmic reticulum. The oocyte cytoplasm also contains characteristic disc-shaped bodies and cortical granules. A comparative analysis of the proteinaceous yolk formation in different crustaceans reveals two distinct types of vitellogenesis (autosynthesis and heterosynthesis), and indicates that a mixed type prevails in these arthropods. In most crustacean species, germline cells associate with somatic follicle cells that may fulfill several functions during oogenesis.

Zur Geschlechtsbestimmung und Gametogenese von Bonellia viridis Rolando

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 169-193
Author(s):  
Von Rudolf Leutert
Keyword(s):  
Sea Water ◽  
Sex Differentiation ◽  
Follicle Cells ◽  
Sensitive Period ◽  
Nurse Cells ◽  
Larval Life ◽  
Coelomic Cavity ◽  
Male And Female ◽  
Large Numbers ◽  
Electron Microscopical

Sex differentiation and gametogenesis in Bonellia viridis Rolando Large numbers of trochophore larvae of Bonellia viridis (Echiurida) were cultivated either in pure sea water (‘Glaszuchten’) or in sea water containing an intact or fragmented proboscis of an adult female (‘Rüsselzuchten’). The ability of these larvae to differentiate into males or females was investigated. Sex determination for the majority (43–83 %) is metagamic and phenotypic. These findings therefore confirm the results of Baltzer and disprove those of Wilczynski. When larvae are exposed to the action of the female proboscis, 76 % become males. The sensitive period during which this determination can take place lasts from day 3 to day 16 of larval life. Exceptions to this rule are discussed. The gametogenesis of Bonellia viridis has been investigated by electron microscopical methods. In early stages the oogonia of the ovary are already in syncytial contact with the nurse cells. The possible functions of the nurse cells and follicle cells are discussed. Electron micrographs failed to reveal two types of eggs (male- and female-determined eggs, according to Wilczynski). Spermiogenesis in Bonellia is described. The spermatogonia are situated in paired clusters in the coelomic cavity, and form a syncytial complex. After completion of spermiogenesis, the spermatozoa abandon their syncytial contact. The fine structure of ripe spermatozoa is described and discussed.

scholarly journals Binding of SU(VAR)3-9 Partially Depends on SETDB1 in the Chromosomes of Drosophila melanogaster

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1030 ◽  
Author(s):  
Daniil A. Maksimov ◽  
Dmitry E. Koryakov
Keyword(s):  
Developmental Stages ◽  
Critical Role ◽  
Single Copy ◽  
Nurse Cells ◽  
Wild Type ◽  
Histone Methyltransferases ◽  
Adult Females ◽  
Germline Cells ◽  
Differentiation Stage ◽  
Female Germline

H3K9 methylation is known to play a critical role in gene silencing. This modification is established and maintained by several enzymes, but relationships between them are not fully understood. In the present study, we decipher the interplay between two Drosophila H3K9-specific histone methyltransferases, SU(VAR)3-9 and SETDB1. We asked whether SETDB1 is required for targeting of SU(VAR)3-9. Using DamID-seq, we obtained SU(VAR)3-9 binding profiles for the chromosomes from larval salivary glands and germline cells from adult females, and compared profiles between the wild type and SETDB1-mutant backgrounds. Our analyses indicate that the vast majority of single copy genes in euchromatin are targeted by SU(VAR)3-9 only in the presence of SETDB1, whereas SU(VAR)3-9 binding at repeated sequences in heterochromatin is largely SETDB1-independent. Interestingly, piRNA clusters 42AB and 38C in salivary gland chromosomes bind SU(VAR)3-9 regardless of SETDB1, whereas binding to the same regions in the germline cells is SETDB1-dependent. In addition, we compared SU(VAR)3-9 profiles in female germline cells at different developmental stages (germarium cells in juvenile ovaries and mature nurse cells). It turned out that SU(VAR)3-9 binding is influenced both by the presence of SETDB1, as well as by the differentiation stage.

Inhibition of DMRTA2 impairs human female germline development in xeno-grafted ovaries

2014 ◽  
Author(s):  
Marine Poulain ◽  
Sophie Tourpin ◽  
Vincent Muczynski ◽  
Sebastien Messiaen ◽  
Delphine Moison ◽  
...  
Keyword(s):  
Human Female ◽  
Germline Development ◽  
Female Germline

scholarly journals The Mammalian Ovary from Genesis to Revelation

2009 ◽  
Vol 30 (6) ◽  
pp. 624-712 ◽  
Author(s):  
Mark A. Edson ◽  
Ankur K. Nagaraja ◽  
Martin M. Matzuk
Keyword(s):  
Germ Cells ◽  
Ovarian Function ◽  
Primordial Germ Cells ◽  
Bioactive Molecules ◽  
Sex Characteristics ◽  
Germline Development ◽  
Peptide Growth Factors ◽  
Development And Differentiation ◽  
Common Destiny ◽  
Female Germline

Abstract Two major functions of the mammalian ovary are the production of germ cells (oocytes), which allow continuation of the species, and the generation of bioactive molecules, primarily steroids (mainly estrogens and progestins) and peptide growth factors, which are critical for ovarian function, regulation of the hypothalamic-pituitary-ovarian axis, and development of secondary sex characteristics. The female germline is created during embryogenesis when the precursors of primordial germ cells differentiate from somatic lineages of the embryo and take a unique route to reach the urogenital ridge. This undifferentiated gonad will differentiate along a female pathway, and the newly formed oocytes will proliferate and subsequently enter meiosis. At this point, the oocyte has two alternative fates: die, a common destiny of millions of oocytes, or be fertilized, a fate of at most approximately 100 oocytes, depending on the species. At every step from germline development and ovary formation to oogenesis and ovarian development and differentiation, there are coordinated interactions of hundreds of proteins and small RNAs. These studies have helped reproductive biologists to understand not only the normal functioning of the ovary but also the pathophysiology and genetics of diseases such as infertility and ovarian cancer. Over the last two decades, parallel progress has been made in the assisted reproductive technology clinic including better hormonal preparations, prenatal genetic testing, and optimal oocyte and embryo analysis and cryopreservation. Clearly, we have learned much about the mammalian ovary and manipulating its most important cargo, the oocyte, since the birth of Louise Brown over 30 yr ago.

scholarly journals Differentiating Drosophila female germ cells initiate Polycomb silencing by regulating PRC2-interacting proteins

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Steven Z DeLuca ◽  
Megha Ghildiyal ◽  
Liang-Yu Pang ◽  
Allan C Spradling
Keyword(s):  
Interacting Proteins ◽  
Nurse Cells ◽  
Germline Stem Cells ◽  
Developmentally Regulated ◽  
Canonical Distribution ◽  
Polycomb Repressive Complex 2 ◽  
Animal Development ◽  
Target Sites ◽  
Female Germline ◽  
Inactive Chromatin

Polycomb silencing represses gene expression and provides a molecular memory of chromatin state that is essential for animal development. We show that Drosophila female germline stem cells (GSCs) provide a powerful system for studying Polycomb silencing. GSCs have a non-canonical distribution of PRC2 activity and lack silenced chromatin like embryonic progenitors. As GSC daughters differentiate into nurse cells and oocytes, nurse cells, like embryonic somatic cells, silence genes in traditional Polycomb domains and in generally inactive chromatin. Developmentally controlled expression of two Polycomb repressive complex 2 (PRC2)-interacting proteins, Pcl and Scm, initiate silencing during differentiation. In GSCs, abundant Pcl inhibits PRC2-dependent silencing globally, while in nurse cells Pcl declines and newly induced Scm concentrates PRC2 activity on traditional Polycomb domains. Our results suggest that PRC2-dependent silencing is developmentally regulated by accessory proteins that either increase the concentration of PRC2 at target sites or inhibit the rate that PRC2 samples chromatin.

maelstrom is required for an early step in the establishment of Drosophila oocyte polarity: posterior localization of grk mRNA

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4661-4671 ◽  
Author(s):  
N.J. Clegg ◽  
D.M. Frost ◽  
M.K. Larkin ◽  
L. Subrahmanyan ◽  
Z. Bryant ◽  
...  
Keyword(s):  
Nurse Cell ◽  
Egf Receptor ◽  
Mrna Localization ◽  
Follicle Cells ◽  
Rna Transport ◽  
Nurse Cells ◽  
Loss Of Function ◽  
Cell Fates ◽  
Early Step ◽  
Novel Protein

We describe a mutant, maelstrom, that disrupts a previously unobserved step in mRNA localization within the early oocyte, distinct from nurse-cell-to-oocyte RNA transport. Mutations in maelstrom disturb the localization of mRNAs for Gurken (a ligand for the Drosophila Egf receptor), Oskar and Bicoid at the posterior of the developing (stage 3–6) oocyte. maelstrom mutants display phenotypes detected in gurken loss-of-function mutants: posterior follicle cells with anterior cell fates, bicoid mRNA localization at both poles of the stage 8 oocyte and ventralization of the eggshell. These data are consistent with the suggestion that early posterior localization of gurken mRNA is essential for activation of the Egf receptor pathway in posterior follicle cells. Posterior localization of mRNA in stage 3–6 oocytes could therefore be one of the earliest known steps in the establishment of oocyte polarity. The maelstrom gene encodes a novel protein that has a punctate distribution in the cytoplasm of the nurse cells and the oocyte until the protein disappears in stage 7 of oogenesis.

Origin and spatial distribution of maternal messenger RNA during oogenesis of an insect, Oncopeltus fasciatus

1979 ◽  
Vol 39 (1) ◽  
pp. 63-76
Author(s):  
D.G. Capco ◽  
W.R. Jeffery
Keyword(s):  
Spatial Distribution ◽  
Messenger Rna ◽  
Germinal Vesicle ◽  
Oncopeltus Fasciatus ◽  
Follicle Cells ◽  
Rna Molecules ◽  
Maternal Mrna ◽  
Chorion Formation ◽  
Oocyte Cytoplasm ◽  
Rna Accumulation

In order to investigate the origin and spatial distribution of maternal mRNA during oogenesis, in situ hybridization with [3H]-poly(U) was utilized for the detection of poly(A)-containing RNA [poly(A)+RNA] in histological sections of Oncopeltus fasciatus ovaries. In the germarium poly(A)+RNA was found to accumulate in the trophocyte cytoplasm concomitant with the maturation of these cells. Poly(A)+RNA was also detected in the trophic cores and nutritive tubes suggesting that these channels participate in the transport of trophocyte-derived mRNA to the oocytes. Although large amounts of poly(A)+RNA were also detected in the cytoplasm of the follicle cells, particularly during late vitellogenesis when pseudopod-like processes projected into the ooplasm, no evidence was obtained for the transport of poly(A)+RNA from these processes to the oocytes. The content of poly(A)+RNA in the oocyte cytoplasm continually increased during oogenesis. In stage 2–4 oocytes poly(A)+RNA accumulation occurred in the apparent absence of transcriptional activity in the germinal vesicle nuclei suggesting that most maternal mRNA molecules synthesized during early oogenesis are of trophocyte origin. Poly(A)+RNA also continued to accumulate after chorion formation, when the nutritive tubes are longer active in RNA transport. This implies that other sources of maternal mRNA may exist during late oogenesis. The distribution of poly(A)+RNA molecules in the oocyte cytoplasm appeared to be uniform throughout oogenesis with one exception. During late vitellogenesis poly(A)+RNA activity was significantly enhanced in the anterior and posterior periplasmic cytoplasms relative to the lateral periplasm and the endoplasm. After chorion formation these variations disappeared. The results suggest that maternal mRNA molecules arise from at least 2 sources during oogenesis. During late vitellogenesis these molecules appear to be subject to differential localization in the polar perimeters of the oocyte cytoplasm.

Infection of the germ line by retroviral particles produced in the follicle cells: a possible mechanism for the mobilization of the gypsy retroelement of Drosophila

Development ◽  
1997 ◽  
Vol 124 (14) ◽  
pp. 2789-2798 ◽  
Author(s):  
S.U. Song ◽  
M. Kurkulos ◽  
J.D. Boeke ◽  
V.G. Corces
Keyword(s):  
High Frequency ◽  
Cytoplasmic Membrane ◽  
De Novo ◽  
Germ Line ◽  
High Rate ◽  
Follicle Cells ◽  
Nurse Cells ◽  
Perivitelline Space ◽  
Viral Particles ◽  
Secretory Apparatus

The gypsy retroelement of Drosophila moves at high frequency in the germ line of the progeny of females carrying a mutation in the flamenco (flam) gene. This high rate of de novo insertion correlates with elevated accumulation of full-length gypsy RNA in the ovaries of these females, as well as the presence of an env-specific RNA. We have prepared monoclonal antibodies against the gypsy Pol and Env products and found that these proteins are expressed in the ovaries of flam females and processed in the manner characteristic of vertebrate retroviruses. The Pol proteins are expressed in both follicle and nurse cells, but they do not accumulate at detectable levels in the oocyte. The Env proteins are expressed exclusively in the follicle cells starting at stage 9 of oogenesis, where they accumulate in the secretory apparatus of the endoplasmic reticulum. They then migrate to the inner side of the cytoplasmic membrane where they assemble into viral particles. These particles can be observed in the perivitelline space starting at stage 10 by immunoelectron microscopy using anti-Env antibodies. We propose a model to explain flamenco-mediated induction of gypsy mobilization that involves the synthesis of gypsy viral particles in the follicle cells, from where they leave and infect the oocyte, thus explaining gypsy insertion into the germ line of the subsequent generation.

scholarly journals Four Departmental Asylums in the North-West of France

1874 ◽  
Vol 19 (88) ◽  
pp. 541-552
Author(s):  
J. Wilkie Burman
Keyword(s):  
Small Town ◽  
Great Majority ◽  
Waste Paper ◽  
Maintenance Rate ◽  
North West ◽  
The North ◽  
Walking Tour ◽  
Large Numbers ◽  
Close Proximity ◽  
Lunatic Asylums

In the course of a walking tour, during last summer, I visited, en route, four of the Departmental Lunatic Asylums in the North-West of France, principally with a view to see how they would stand comparison with our own Provincial or County Asylums. Such a comparison, however, could scarcely, I find, be made on a fair basis; for though, undoubtedly, the great majority of the patients in the French Departmental Asylums are paupers, and maintained at the expense of the several Departments, yet, in all, there are associated with these paupers large numbers of pensionnaires, who are maintained by theirfriends and divided into four or five classes, and treated according to their rate of payment. It is obvious, moreover, that the better general and special arrangements, due to and supported by the higher rates of payment of the pensionnaires, would prevent such associated asylums as these from being fairly compared, as to their tout ensemble, with our own County Asylums—in which, as a rule, the patients are all paupers, and chargeable to the different unions, and in which the arrangements are for paupers only, and so constituted as to keep the maintenance rate as low as is compatible with efficiency. Seeing, then, that it was impossible to institute any fair general comparison between the French Departmental Asylums, which I lately visited, and our own County Asylums, I determined, whilst not failing to pay all due regard to the arrangements for, and treatment of, the pensionnaires, to pay more particular attention to the condition and treatment of the pauper patients in the Asylums visited, and to take my notes accordingly. These rough notes, instead of consigning them to the waste paper basket, as has been the fate of former notes of visits made by me to Continental Asylums, I have, this time, determined to offer to my professional brethren, in the hope that they may afford, perhaps, some few crumbs of information and of interest. It will be necessary for me, however, before going further, to state—that, as the principal object of my tour was walking and not mad-house hunting, I did not follow out any predetermined plan as to which particular asylums I should visit. Indeed, it was not until I had well started on my tour that I conceived the laudable idea of endeavouring to combine a little instruction with my amusement, and the result was that I merely visited those asylums which were in close proximity to the route which I had arranged for myself previous to starting. The asylums to which I paid these hap-hazard visits, then, were the following:—1st, “L'Asile de Lehon,” Dinan; 2nd, “L'Asile St. Athanase,” Quimper; 3rd, “L'Asile St. Méen,” Rennes; and 4, “L'Asile de Pontorson,” situated in the small town of that name; and I shall record my notes of them, seriatim, in the order in which they were visited.

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