Oogenesis in Lucilia Cuprina (Wied.) (Diptera: Calliphoridae). I. Development of Nurse Cell Nuclei, the Oocyte Nucleus and the Follicle Cells.

1979 ◽  
Vol 27 (3) ◽  
pp. 331 ◽  
Author(s):  
GAC Beattie ◽  
J Cheney
Keyword(s):  
Nurse Cell ◽  
Early Stage ◽  
Chromosomal Rearrangements ◽  
Polytene Chromosomes ◽  
Average Diameter ◽  
Lucilia Cuprina ◽  
Follicle Cells ◽  
Oocyte Nucleus ◽  
Cell Nuclei ◽  
Stage 1

In investigations in the laboratory in Australia, endomitosis in the ovarian nurse cell nuclei in females of Lucilia cuprina (Wied.) was found to be initiated in stage-1 follicles shortly after eclosion, independently of a protein meal. The largest nurse cell nuclei attained a ploidy of 1024n in stage 3 and 4 follicles, shortly after the onset of vitellogenesis; after this, they could undergo a further eightfold increase in volume. Polytene chromosomes were occasionally observed during endomitosis in 16n and 32n nurse cell nuclei. Throughout stages 1-8, the oocyte nucleus steadily increased from an average diameter of 6-7 mu m to one of about 60 mu m. In early stage 9, the nuclear membrane was lost and what appeared to be a karyosphere with a diameter of about 6 mu m was visible. Later in stage 9, the oocyte nucleus was obscured by yolk, and its development beyond this stage was not traced. Follicle cells increased in number from 80 in early stage-1 follicles to 1300 in stage 2. The information presented was required to ascertain the site of action of aziridinyl chemosterilants on ovarian development [see next abstract] and to aid in current research on the production of chromosomal rearrangements by irradiation.

Oogenesis in Lucilia Cuprina (Wied.) (Diptera: Calliphoridae). Ii. The Effect of Aziridinyl Chemosterilants on Oogenesis.

1979 ◽  
Vol 27 (3) ◽  
pp. 349 ◽  
Author(s):  
GAC Beattie
Keyword(s):  
Direct Effect ◽  
Nurse Cell ◽  
Ovarian Development ◽  
Fat Body ◽  
Endocrine System ◽  
Lucilia Cuprina ◽  
Follicle Cells ◽  
Cell Nuclei

Inhibition of ovarian development in L. cuprina by two aziridinyl chemosterilants, N,N'-hexamethylenebis(1-aziridinecarboxamide) and N. N'bisaziridinyl-N"-cyclohexylphosphine sulphide, was due to the direct effect of the sterilants on the ovary. The sterilants caused infecundity by interfering with mitosis in the follicle cells. Contrary to the accepted view, no evidence was obtained to suggest that infecundity resulted from inhibition of endomitosis in the nurse cell nuclei. Neither sterilant prevented the digestion of protein by the midgut, nor did they prevent the endocrine system and fat body from functioning.

scholarly journals INTERCELLULAR MIGRATION OF CENTRIOLES IN THE GERMARIUM OF DROSOPHILA MELANOGASTER

1970 ◽  
Vol 45 (2) ◽  
pp. 306-320 ◽  
Author(s):  
Anthony P. Mahowald ◽  
Joan M. Strassheim
Keyword(s):  
Follicle Cell ◽  
Cell Cluster ◽  
Follicle Cells ◽  
Oocyte Nucleus ◽  
Nurse Cells ◽  
Serial Sections ◽  
Cell Border ◽  
Ring Canals ◽  
Egg Chambers ◽  
Stage 1

A cluster of centrioles has been found in the early Drosophila oocyte. Since the oocyte is connected to 15 nurse cells by a system of intercellular bridges or ring canals, the possibility that the cluster of centrioles arose in the germarium from an intercellular migration of centrioles from the nurse cells to the oocyte was analyzed in serial sections for the electron microscope. Initially, all of the 16 cells of the future egg chambers possess centrioles, which are located in a juxtanuclear position. At the time the 16 cell cluster becomes arranged in a lens-shaped layer laterally across the germarium, the centrioles lose their juxtanuclear position and move towards the oocyte. By the time the 16 cell cluster of cells is surrounded by follicle cells (Stage 1), between 14 and 17 centrioles are found in the oocyte. Later, these centrioles become located between the oocyte nucleus and the follicle cell border and become aggregated into a cluster less than 1.5 µ in its largest dimension. The fate of these centrioles in the oocyte is not known. The fine structure of the germarium and the early oocyte is also described.

Memoirs: Certain Phenomena of Tenthredinid Oogenesis as Revealed Mainly by Feulgen's Nuclear-Reaction

1930 ◽  
Vol s2-73 (292) ◽  
pp. 617-630
Author(s):  
R.A. R. GRESSON
Keyword(s):  
Nurse Cell ◽  
Chemical Change ◽  
Follicle Cell ◽  
Nuclear Material ◽  
Methyl Blue ◽  
Follicle Cells ◽  
Nuclear Chromatin ◽  
Nurse Cells ◽  
Cell Nuclei ◽  
Nucleolar Material

1. By the use of Feulgen's ‘nuclealreaktion’ certain points of Tenthredinid oogenesis have been subjected to closer study. The chromatin of the early nurse-cells of Allantus pallipes exists in the form of granules, the majority of which occur close to the nuclear membrane. In the older cells a nuclear network appears in which is distributed granules of chromatin. In Thrinax mixta, where the ovarioles were more highly developed, the chromatin of the nurse-cells occurs as granules scattered through the nucleus; a nuclear network is not present, but certain granules appear to be connected by a thread. The granules which were shown to surround the nurse-cell nuclei (in material treated by Bensley's method and also by fixation in Bouin's picro-formol and subsequently stained in iron haematoxylin) and which were formerly regarded as chromatin emissions from the nurse-cell nuclei (9) were not revealed by Feulgen's technique. They therefore cannot be regarded as chromatin. Their precise nature and origin remains undetermined. 2. The nucleoli of the early nurse-cells of both species, as revealed by Mann's methyl-blue eosin, are faintly basophil. Later they break up into a number of basophil bodies which undergo fragmentation; formerly (technique and reference as in 1) the basophil nucleolus and the basophil bodies originating from it were termed ‘nuclear material’ undergoing fragmentation. While this basophil nucleolar material presents a fragmented appearance, it increases in amount as evidenced by the large number of basophil bodies present in the older nurse-cell nuclei. This material is utilized for the nourishment of the egg after the latter engulfs the nurse-cell nuclei. Nucleolar extrusions to the cytoplasm do not occur. 3. The behaviour of the chromatin of the follicle-cell nuclei is similar to that of the nurse-cell nuclei except that in Allantus pallipes the nuclear chromatin network as demonstrated by Feulgen's technique disappears in the older cells. 4. The nucleoli of the follicle-cells are basophil. They become broken up in the older cells, but in most cases the resulting masses remain in contact. Nucleolar extrusions to the cytoplasm do not occur. 5. The occurrence of deeply basophil material in the cytoplasm of the follicle-cells of Thrinax mixta stained with Mann's methyl-blue eosin, formerly described for Bouin fixed material stained in iron haematoxylin (9), suggests that some substance in solution may be passed into the ooplasm; extrusion of granules from the follicle-cells to the ooplasm does not take place. 6. The absence or non-visibility of chromatin (Feulgen's technique) from the oocytes of Thrinax mixta, and its disappearance from the older oocytes of Allantus pallipes , would indicate that the chromatin undergoes a chemical change during oogenesis such as suggested by Koch for Chilopods. 7. The oxyphil and basophil nucleoli of the oocytes do not react to Feulgen's technique for chromatin; this agrees with Ludford's findings for the mouse and for Limnaeastagnalis.

scholarly journals Domains of the Pavarotti kinesin-like protein that direct its subcellular distribution: effects of mislocalisation on the tubulin and actin cytoskeleton during Drosophila oogenesis

2002 ◽  
Vol 115 (4) ◽  
pp. 725-736 ◽  
Author(s):  
Gianluca Minestrini ◽  
Endre Máthé ◽  
David M. Glover
Keyword(s):  
Actin Cytoskeleton ◽  
Nurse Cell ◽  
Oocyte Nucleus ◽  
Subcellular Localisation ◽  
Cell Nuclei ◽  
Cortical Actin ◽  
Atp Binding Site ◽  
Ring Canals ◽  
Cytoplasmic Microtubules ◽  
Mutant Forms

The kinesin-like protein encoded by pavarotti (Pav-KLP) is essential for cytokinesis and associates with the central part of the late mitotic spindle and interphase nuclei in somatic cells (Adams et al., 1988). Here we define regions of the molecule that regulate its subcellular localisation and study the consequences of overexpressing mutant forms of the protein during oogenesis in Drosophila. Pav-KLP normally associates with the oocyte nucleus, but when over-expressed at moderate levels, its GFP tagged form also accumulates in nurse cell nuclei. At high expression levels this leads to loss of the microfilaments that tether these nuclei, so that they block the ring canals and prevent the `dumping' of nurse cell cytoplasm into the oocyte, which results in sterility. Localisation to these nuclei is prevented by mutations in either the conserved ATP-binding site of the motor domain or the nuclear localisation sequences in the C-terminal domain. Both such mutations lead to the formation of stable arrays of cytoplasmic microtubules and the progressive disruption of the actin cytoskeleton. The latter is evident by a breakdown of the cortical actin causing disruption of cell membranes; this breakdown ultimately results in the accumulation of cytoplasmic aggregates containing tubulin, actin and at least some of their binding proteins. Pav-KLP is also found associated with the ring canals,actin-rich structures built from remnants of the cytokinesis ring. The stalk domain alone is sufficient for the exclusive association of Pav-KLP to these structures, and this has no consequences for fertility. We discuss whether disruption of actin structures by full-length cytoplasmic forms of Pav-KLP is a consequence of the resulting stabilised cytoplasmic microtubules per se or accumulation of the motor protein at ectopic cortical sites to sequester molecules that regulate actin behaviour.

Alterations in the number of motoneurons containing immunoreactive calcitonin gene-related peptide(CGRP)& choline acetyltransferase(ChAT) in the cervical spinal cord of the wobbler mouse during the development of the motoneuron disease

1995 ◽  
Vol 53 ◽  
pp. 970-971
Author(s):  
L. Vacca-Galloway ◽  
Y.Q. Zhang ◽  
P. Bose ◽  
S.H. Zhang
Keyword(s):  
Spinal Cord ◽  
Early Stage ◽  
Cervical Spinal Cord ◽  
Wild Type Mouse ◽  
Reflex Response ◽  
Mouse Strains ◽  
Behavioral Tests ◽  
Wobbler Mouse ◽  
Stage 4 ◽  
Stage 1

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.

scholarly journals Temporal changes of quantitative CT findings from 102 patients with COVID-19 in Wuhan, China: A longitudinal study

2021 ◽  
Vol 29 ◽  
pp. 297-309
Author(s):  
Xiaohui Chen ◽  
Wenbo Sun ◽  
Dan Xu ◽  
Jiaojiao Ma ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Lung Diseases ◽  
Early Stage ◽  
Temporal Changes ◽  
Time Interval ◽  
Lesion Area ◽  
Quantitative Ct ◽  
Diagnosis And Prognosis ◽  
Ct Findings ◽  
Stage 4 ◽  
Stage 1

BACKGROUND: Computed tomography (CT) imaging combined with artificial intelligence is important in the diagnosis and prognosis of lung diseases. OBJECTIVE: This study aimed to investigate temporal changes of quantitative CT findings in patients with COVID-19 in three clinic types, including moderate, severe, and non-survivors, and to predict severe cases in the early stage from the results. METHODS: One hundred and two patients with confirmed COVID-19 were included in this study. Based on the time interval between onset of symptoms and the CT scan, four stages were defined in this study: Stage-1 (0 ∼7 days); Stage-2 (8 ∼ 14 days); Stage-3 (15 ∼ 21days); Stage-4 (> 21 days). Eight parameters, the infection volume and percentage of the whole lung in four different Hounsfield (HU) ranges, ((-, -750), [-750, -300), [-300, 50) and [50, +)), were calculated and compared between different groups. RESULTS: The infection volume and percentage of four HU ranges peaked in Stage-2. The highest proportion of HU [-750, 50) was found in the infected regions in non-survivors among three groups. CONCLUSIONS: The findings indicate rapid deterioration in the first week since the onset of symptoms in non-survivors. Higher proportion of HU [-750, 50) in the lesion area might be a potential bio-marker for poor prognosis in patients with COVID-19.

The endocycle controls nurse cell polytene chromosome structure during Drosophila oogenesis

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 293-303 ◽  
Author(s):  
K.J. Dej ◽  
A.C. Spradling
Keyword(s):  
Polytene Chromosome ◽  
Nurse Cell ◽  
Chromosome Structure ◽  
Polytene Chromosomes ◽  
S Phase ◽  
Nurse Cells ◽  
Chromosome Behavior ◽  
M Phase ◽  
Diploid Cells ◽  
Polytene Nuclei

Polytene chromosomes exhibit intricate higher order chromatin structure that is easily visualized due to their precisely aligned component strands. However, it remains unclear if the same factors determine chromatin organization in polyploid and diploid cells. We have analyzed one such factor, the cell cycle, by studying changes in Drosophila nurse cell chromosomes throughout the 10 to 12 endocycles of oogenesis. We find that nurse cells undergo three distinct types of endocycle whose parameters are correlated with chromosome behavior. The first four endocycles support complete DNA replication; poorly banded polytene euchromatin progressively condenses during the late S phases to produce blob-like chromosomes. During the unique fifth endocycle, an incomplete late S phase is followed by a mitosis-like state during which the 64C chromosomes dissociate into 32 chromatid pairs held together by unreplicated regions. All the subsequent endocycles lack any late S phase; during these cycles a new polytene chromosome grows from each 2C chromatid pair to generate 32-ploid polytene nuclei. These observations suggest that euchromatin begins to condense during late S phase and that nurse cell polytene chromosome structure is controlled by regulating whether events characteristic of late S and M phase are incorporated or skipped within a given endocycle.

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.

The TGF-beta signaling pathway is essential for Drosophila oogenesis

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1555-1565 ◽  
Author(s):  
V. Twombly ◽  
R.K. Blackman ◽  
H. Jin ◽  
J.M. Graff ◽  
R.W. Padgett ◽  
...  
Keyword(s):  
Family Member ◽  
Signaling Pathway ◽  
Expression Pattern ◽  
Nurse Cell ◽  
Follicle Cells ◽  
Tgf Beta ◽  
Drosophila Oogenesis ◽  
Egg Chamber

We examine roles of signaling by secreted ligands of the TGF-beta family during Drosophila oogenesis. One family member, the DPP ligand encoded by the decapentaplegic (dpp) gene, is required for patterning of anterior eggshell structures. This requirement presumably reflects the expression pattern of dpp in an anterior subset of somatic follicle cells: the centripetally migrating and the nurse cell-associated follicle cells. Similar requirements are also revealed by mutations in the saxophone (sax)-encoded receptor, consistent with the idea that DPP signaling is, at least in part, mediated by the SAX receptor. A loss of germline sax function results in a block in oogenesis associated with egg chamber degeneration and a failure of the transfer of nurse cell contents to the oocyte, indicating that TGF-beta signaling is required for these events. Some phenotypes of sax mutations during oogenesis suggest that SAX responds to at least one other TGF-beta ligand as well in the posterior follicle cells.

Memoirs: The Formation and Structure of the Chorion of the Egg in an Hemipteran, Rhodnius prolixus

1946 ◽  
Vol s2-87 (348) ◽  
pp. 393-439
Author(s):  
J. W. BEAMENT
Keyword(s):  
Average Diameter ◽  
Water Soluble ◽  
Follicle Cells ◽  
Protein Layer ◽  
Secretory Products ◽  
Large Water ◽  
Protein Components ◽  
Egg Shell ◽  
Pore Canals ◽  
Strong Acids

The main regions of the Ehodnius prolixus egg-shell have been defined; a concise definition has been obtained for the term ‘chorion’. The formation and structure of the unspecialized chorion has been followed from the time of differentiation of the follicle cells, up to the completion of the shell, and an assessment made of the chemistry and permeability of each component shell layer. The follicle cells are binucleate; changes in morphology and histology prior to secretion of the shell are outlined. The secretory products of the follicle cells fall naturally into an endochorion and an exochorion; the endochorion consists of five modifications of a proteinaceous substance. They are, in order of secretion: 1. The Inner Polyphenol Layer, which consists of a series of tanned granules of average diameter 2µ, containing large quantities of polyphenols. The layer is discontinuous and has no effect on permeability. 2. The Resistant Protein Layer, a tanned and possibly vulcanized layer of protein, 1 to 2µ, thick, containing diffuse polyphenols. It is resistant to strong acids and bases, and permeable to water, ions, and large water-soluble molecules. 3. The Outer Polyphenol Layer, which is similar to the inner layer, but has more minute granules. 4. The Amber Layer.--This is the only coloured layer of the shell, and is less than 0-1µthick. It consists of tanned protein to which oil is added after secretion. It is therefore a lipidized protein, which is excessively resistant to acids and alkalies, and permeable to oils and oil-soluble material and to small ions and water. 5. The Soft Protein Layer.--This is a thick laminated layer some 8µ. thick, similar to, but less resistant than, the resistant protein layer. It contains polyphenols and tyrosine. The layer is freely permeable to water-soluble substances. Throughout the secretion of the endochorion, the follicle cells stain deeply and appear to be filled with the protein components of the shell. The exochorion consists of two layers of the lipoprotein ‘chorionin’. 6. The Soft Exochorion Layer is a lipoprotein which is soluble in potash but not in strong acids; the layer is permeable to lipoid solvents and to water and small ions, but not to larger particles. It is 8µ thick at its maximum thickness, but contains follicular pits which, during secretion, are filled by long processes from the follicle cells. 7. The Eesistant Exochorion Layer is a more resistant form of chorionin. It lines the pits and covers the surface of the shell, giving rise to the polygonal markings corresponding to the follicle cells, each with a pit at its centre. The follicle cells contain quantities of lipoprotein during this phase of secretion, and are difficult to stain. A method of staining is described which shows that pore canals of two varieties are present in the exochorion layers only. They run from the walls of the pits but do not reach the endochorion. None of the layers of the chorion waterproofs the shell. In the rear end of the shell, the outer polyphenol layer is displaced towards the exochorion, thus increasing the resistant protein layer and reducing the soft protein layer. It is shown that all seven layers are present in the neck, and in the central region of the cap, and that the order of secretion is the same. Modifications are produced by variations in the thickness of the various layers. In the neck, the soft protein layer is reduced; in the cap, the resistant protein layer is reduced while the amber layer is 2µ thick, giving the cap a brown appearance. The soft protein layer is extremely thin and irregular while the exochorion layers are 16 µ thick. Pore canals are again present in two varieties. Some analysis is made of the formation of follicular pits; this appears to be correlated with the thickness of the exochorion and endochorion layers.

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