THE FORMATION OF COMPOUND EGG CHAMBERS IN A BUG (HEMIPTERA) STERILIZED WITH 6-AZAURIDINE

1971 ◽  
Vol 103 (8) ◽  
pp. 1063-1078 ◽  
Author(s):  
Petr Masner ◽  
Vladimir Landa
Keyword(s):  
Dna Replication ◽  
Nucleic Acid ◽  
Mitotic Activity ◽  
Follicular Cells ◽  
Nutritive Tissue ◽  
Target Organs ◽  
Egg Chambers ◽  
Egg Chamber ◽  
Rich Material

AbstractOvaries are one of the target organs hit by the nucleic acid antimetabolite 6-azauridine. All the malformations observed are caused by the suppression of mitotic activity, which appears to be the most sensitive to the applied drug. The inhibition of mitosis in the apical trophocytes results in depletion of the nutritive tissue in older females, followed by a disturbance of previtellogenesis and activation of oocytes. The blocked mitotic multiplication of prefollicular tissue results in exhaustion of this layer followed by a disturbance of regular egg chamber formation. The inadequate separation of oocytes by follicular cells causes the arrangement of the oocytes in paired chambers, often blocking the ovariole, or the formation of compound chambers. The oocytes sharing the compound chamber either remain separated by the ooplasmalemma or merge. Eggs with adherent dwarf oocytes or giant fused double eggs are oviposited. Endomitotic DNA replication and amitotic karyokinesis of the follicular cells are not interfered with by 6-azauridine, probably owing to the nucleic acid pools contained in the haemolymph. The lecytholitic cells resorb the ooplasm utilizing the nucleic acid-rich material.

Apoptosis in late stage Drosophila nurse cells does not require genes within the H99 deficiency

Development ◽  
1998 ◽  
Vol 125 (6) ◽  
pp. 1075-1082 ◽  
Author(s):  
K. Foley ◽  
L. Cooley
Keyword(s):  
Dna Fragmentation ◽  
Late Stage ◽  
Expression Patterns ◽  
Nuclear Material ◽  
Nurse Cells ◽  
Wild Type ◽  
Negative Regulators ◽  
Egg Chambers ◽  
Positive Regulators ◽  
Egg Chamber

We have determined that nurse cells are cleared from the Drosophila egg chamber by apoptosis. DNA fragmentation begins in nurse cells at stage 12, following the completion of cytoplasm transfer from the nurse cells to the oocyte. During stage 13, nurse cells increasingly contain highly fragmented DNA and disappear from the egg chamber concomitantly with the formation of apoptotic vesicles containing highly fragmented nuclear material. In dumpless mutant egg chambers that fail to complete cytoplasm transport from the nurse cells, DNA fragmentation is markedly delayed and begins during stage 13, when the majority of cytoplasm is lost from the nurse cells. These data suggest the presence of cytoplasmic factors in nurse cells that inhibit the initiation of DNA fragmentation. In addition, we have examined the ovarian expression patterns of regulatory genes implicated in Drosophila apoptosis. The positive regulators, reaper (rpr), head involution defective (hid) and grim, as well as the negative regulators, DIAP1 and DIAP2, are transcribed during oogenesis. However, germline clones homozygous for the deficiency Df(3)H99, which deletes rpr, hid and grim, undergo oogenesis in a manner morphologically indistinguishable from wild type, indicating that genes within this region are not necessary for apoptosis in nurse cells.

Female Reproductive Function

2011 ◽  
Author(s):  
Sergio R. Ojeda
Keyword(s):  
Granulosa Cells ◽  
Reproductive Function ◽  
Basal Membrane ◽  
Pituitary Hormones ◽  
Follicular Cells ◽  
Outer Cortex ◽  
Animal Fats ◽  
Point Of Entry ◽  
Target Organs ◽  
Attachment Region

The production of germ cells is essential for the continuation of a species. In the female this function is accomplished by the ovaries. In addition, the ovaries secrete steroids and nonsteroidal hormones that not only regulate the secretion of anterior pituitary hormones but also act on various target organs, including the ovaries themselves, the uterus, fallopian tubes, vagina, mammary gland, and bone. Morphologically, the ovary has three regions: an outer cortex that contains the oocytes and represents most of the mass of the ovary; the inner medulla, formed by stromal cells and cells with steroid-producing characteristics; and the hilum, which, in addition to serving as the point of entry of the nerves and blood vessels, represents the attachment region of the gland to the mesovarium. The cortex, which is enveloped by the germinal epithelium, contains the follicles, which are the functional units of the ovary. They are present in different states of development or degeneration (atresia), each enclosing an oocyte. In addition to the oocyte, ovarian follicles have two other cellular components: granulosa cells, which surround the oocyte, and thecal cells, which are separated from the granulosa cells by a basal membrane and are arranged in concentric layers around this membrane. The follicles are embedded in the stroma, which is composed of supportive connective cells similar to that of other tissues, interstitial secretory cells, and neurovascular elements. The medulla has a heterogeneous population of cells, some of which are morphologically similar to the Leydig cells in the testes. These cells predominate in the ovarian hilum; their neoplastic transformation results in excess androgen production. The ovary produces both steroids and peptidergic hormones. Whereas the steroids are synthesized in both interstitial and follicular cells, peptidergic hormones are primarily produced in follicular cells and, after ovulation, by cells of the corpus luteum. The initial precursor for steroid biosynthesis is cholesterol, which derives from animal fats of the diet or from local synthesis.

scholarly journals Visualization of replication initiation and elongation in Drosophila

2002 ◽  
Vol 159 (2) ◽  
pp. 225-236 ◽  
Author(s):  
Julie M. Claycomb ◽  
David M. MacAlpine ◽  
James G. Evans ◽  
Stephen P. Bell ◽  
Terry L. Orr-Weaver
Keyword(s):  
Dna Replication ◽  
Origin Recognition Complex ◽  
Developmental Stages ◽  
Replication Initiation ◽  
Nuclear Antigen ◽  
Minichromosome Maintenance ◽  
Egg Chamber ◽  
Two Phases ◽  
Replication Factors

Chorion gene amplification in the ovaries of Drosophila melanogaster is a powerful system for the study of metazoan DNA replication in vivo. Using a combination of high-resolution confocal and deconvolution microscopy and quantitative realtime PCR, we found that initiation and elongation occur during separate developmental stages, thus permitting analysis of these two phases of replication in vivo. Bromodeoxyuridine, origin recognition complex, and the elongation factors minichromosome maintenance proteins (MCM)2–7 and proliferating cell nuclear antigen were precisely localized, and the DNA copy number along the third chromosome chorion amplicon was quantified during multiple developmental stages. These studies revealed that initiation takes place during stages 10B and 11 of egg chamber development, whereas only elongation of existing replication forks occurs during egg chamber stages 12 and 13. The ability to distinguish initiation from elongation makes this an outstanding model to decipher the roles of various replication factors during metazoan DNA replication. We utilized this system to demonstrate that the pre–replication complex component, double-parked protein/cell division cycle 10–dependent transcript 1, is not only necessary for proper MCM2–7 localization, but, unexpectedly, is present during elongation.

Microstructure of Female Reproductive System of Phenacoccus fraxinus Tang (Hemiptera: Coccoidea: Pseudococcidae)

2008 ◽  
Vol 43 (4) ◽  
pp. 362-372 ◽  
Author(s):  
Xiaohong Fu ◽  
Yingping Xie ◽  
Xiaomin Zhang ◽  
Weimin Liu
Keyword(s):  
Electron Microscopy ◽  
Reproductive System ◽  
Lipid Droplets ◽  
Nurse Cells ◽  
Serial Sections ◽  
Female Reproductive System ◽  
Follicular Cells ◽  
Yolk Lipid ◽  
Egg Chamber ◽  
Scanning Electron

The structure of the female reproductive system of the mealybug, Phenacoccus fraxinus Tang (Hemiptera: Coccoidea: Pseudococcidae), was studied using standard histological examination of serial sections of tissues embedded in paraffin and by scanning electron microscopy. Our studies revealed that the ovary of P. fraxinus has paired lateral oviducts comprised of numerous short ovarioles. Each ovariole consists of 1 trophic chamber, 1 egg chamber and 1 pedicel which connect to the bottom of the egg chamber. Three nurse cells were observed in the trophic chamber, whereas yolk, lipid droplets and an oocyte were seen in the egg chamber. Follicular cells were arranged along the wall of the egg chamber and extended to form the pedicel. Many tracheae and tracheoles of various thicknesses were observed innervating the clusters of ovaries.

INFLUENCE OF THE ADRENAL GLAND ON PROSTATIC ACTIVITY IN ADULT RATS

1973 ◽  
Vol 59 (2) ◽  
pp. 335-344 ◽  
Author(s):  
B. G. MOBBS ◽  
I. E. JOHNSON ◽  
J. G. CONNOLLY
Keyword(s):  
Nucleic Acid ◽  
Adrenal Gland ◽  
Acid Content ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Nucleic Acid Content ◽  
Adult Rats ◽  
Intact Control ◽  
Accessory Sex Glands ◽  
Target Organs

SUMMARY The weight of the accessory sex glands, and the citrate and nucleic acid content of the ventral prostate (VP) glands, were examined in animals which had been adrenalectomized 30 days previously and in intact control rats. Adrenalectomy greatly reduced the citrate content, but did not affect the nucleic acid content of the VP. It was concluded that the adrenals stimulated prostatic function rather than growth. The concentration of radioactivity in the accessory sex glands of adrenalectomized and/or castrated animals after the injection of [3H]testosterone was compared with that in sham-operated controls. Radioactivity was related to the DNA content of the VP of the four groups. It was concluded that adrenalectomy facilitated the uptake and/or retention of androgen. [3H]Corticosterone was not retained by any of the accessory sex glands of animals adrenalectomized and castrated 2 days previously. It seems unlikely that the glands should be considered 'target organs' for corticosterone in the accepted sense of the term, but it is suggested that corticosteroids may help to maintain the balance between differentiation and growth in the VP by influencing the metabolism of androgens by the prostate gland.

scholarly journals Protein—nucleic acid interactions in bacteriophageφ29 DNA replication

1995 ◽  
Vol 17 (1-2) ◽  
pp. 73-82 ◽  
Author(s):  
M. Salas ◽  
R. Freire ◽  
M.S. Soengas ◽  
J.A. Esteban ◽  
J. Méndez ◽  
...  
Keyword(s):  
Dna Replication ◽  
Nucleic Acid ◽  
Protein Nucleic Acid ◽  
Nucleic Acid Interactions

Influence of the RNA content on oogenesis in the bobbed mutants of Drosophila melanogaster

Development ◽  
1971 ◽  
Vol 25 (2) ◽  
pp. 237-246
Author(s):  
Jag Mohan
Keyword(s):  
Drosophila Melanogaster ◽  
Nucleic Acid ◽  
Acid Content ◽  
Nucleic Acid Content ◽  
Wild Type ◽  
Dna And Rna ◽  
Stage Of Development ◽  
Rna Content ◽  
Egg Chambers ◽  
Total Dna

Developing egg chambers of Drosophila melanogaster (wild-type and bobbed mutants) have been examined for their nucleic acid content by cytophotometric methods. No differences were observed in the total DNA and RNA content of the egg chambers at all stages between the bobbed mutants and the wild type. It is shown that the process of oogenesis in bobbed females is prolonged, and that this prolongation occurs at all the stages of oocyte development. Since the ovaries of the bobbed females synthesize less rRNA per unit time, it is likely that this prolongation allows the egg chambers of the bobbed females to normalize their RNA content. When they achieve a given RNA content, they proceed to the next stage of development.

cut interacts with Notch and protein kinase A to regulate egg chamber formation and to maintain germline cyst integrity during Drosophila oogenesis

Development ◽  
1997 ◽  
Vol 124 (18) ◽  
pp. 3663-3672 ◽  
Author(s):  
S.M. Jackson ◽  
K. Blochlinger
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Structural Integrity ◽  
Follicle Cells ◽  
Drosophila Oogenesis ◽  
Cell Complexes ◽  
Genetic Manipulations ◽  
Egg Chambers ◽  
Egg Chamber ◽  
Kinase A

Communications between the germline and the soma during Drosophila oogenesis have been previously shown to be essential for the formation of egg chambers and to establish polarity in the developing oocyte. In this report, we demonstrate that the function of a somatically expressed gene, cut, is critical for maintaining the structural integrity of germline-derived cells and their arrangement within an egg chamber. Genetic manipulations of cut activity resulted in defective packaging of germline-derived cysts into egg chambers and disintegration of the structural organization of oocyte-nurse cell complexes to generate multinucleate germline-derived cells. We also found that cut interacts genetically with the Notch gene and with the catalytic subunit of Protein kinase A gene during egg chamber morphogenesis. Since cut expression is restricted to the somatic follicle cells and cut mutant germline clones are phenotypically normal, we propose that the defects in the assembly of egg chambers and the changes in germline cell morphology observed in cut mutant egg chambers are the result of altered interactions between follicle cells and germline cells. cut encodes a nuclear protein containing DNA-binding motifs, and we suggest that it participates in intercellular communications by regulating the expression of molecules that directly participate in this process.

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