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.

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.

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 Identification of 35 C-Type Lectins in the Oriental Armyworm, Mythimna separata (Walker)

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 559
Author(s):  
Hao Li ◽  
Fang-Fang Liu ◽  
Li-Qing Fu ◽  
Ze Liu ◽  
Wen-Ting Zhang ◽  
...  
Keyword(s):  
Fat Body ◽  
Early Stage ◽  
Average Length ◽  
Phylogenetic Analyses ◽  
Endocrine System ◽  
Economic Loss ◽  
Mythimna Separata ◽  
Oriental Armyworm ◽  
Potential Ligand ◽  
Cellular Immune

Insect C-type lectins (CTLs) play vital roles in modulating humoral and cellular immune responses. The oriental armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae) is a migratory pest that causes significant economic loss in agriculture. CTLs have not yet been systematically identified in M. separata. In this study, we first constructed a transcriptome of M. separata larvae, generating a total of 45,888 unigenes with an average length of 910 bp. Unigenes were functionally annotated in six databases: NR, GO, KEGG, Pfam, eggNOG, and Swiss-Prot. Unigenes were enriched in functional pathways, such as those of signal transduction, endocrine system, cellular community, and immune system. Thirty-five unigenes encoding C-type lectins were identified, including CTL-S1~CTL-S6 (single CRD) and IML-1~IML-29 (dual CRD). Phylogenetic analyses showed dramatic lineage-specific expansions of IMLs. Sequence alignment and structural modeling identified potential ligand-interacting residues. Real-time qPCR revealed that CTL-Ss mainly express in eggs and early stage larvae, while IMLs mainly express in mid-late-stage larvae, pupae, and adults. In naïve larvae, hemocytes, fat body, and epidermis are the major tissues that express CTLs. In larvae challenged by Escherichia coli, Staphylococcus aureus, or Beauveria bassiana, the expression of different CTLs was stimulated in hemocytes, fat body and midgut. The present study will help further explore functions of M. separata CTLs.

scholarly journals Ovarian Development and Vitellogenin Gene Expression under Heat Stress in Silkworm,Bombyx mori

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Satinath Paul ◽  
Bela Keshan
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Heat Shock ◽  
Reproductive Performance ◽  
Ovarian Development ◽  
Fat Body ◽  
Shock Treatment ◽  
Heat Shock Treatment ◽  
Vitellogenin Gene ◽  
Vitellogenin Mrna

The present study observed the effect of heat stress on ovarian development, fecundity, and vitellogenin gene expression in silkworm,Bombyx mori. The result showed that the heat shock treatment to spinning larvae and pupae at 39°C (1 h and 2 h) did not cause any adverse effect on the reproductive performance ofB. mori.However, the heat shock treatment at 42°C or above caused a decrease in the fecundity. The heat shock treatment to day 2 pupae for 2 h at 45°C caused a drastic effect on the development of ovary as measured by gonadosomatic index. The study thus showed that a brief exposure ofBombyxlarvae and pupae to a temperature of 42°C or higher, much prevalent in tropical countries like India, greatly affects the ovarian development and reproductive performance of this commercially important insect. The study further showed a developmental- and tissue-specific expression of vitellogenin mRNA in fat body and ovary upon heat shock. When heat shock treatment was done at 39°C and 42°C to spinning larvae, ovary showed an upregulation in the expression of vitellogenin mRNA, whereas fat body failed to do so. However, at 45°C, both fat body and ovary showed a downregulation. The heat shock treatment to day 2 pupae showed an upregulation in the vitellogenin mRNA expression in both fat body and ovary, even at 45°C. The upregulation in the expression of vitellogenin upon heat shock indicates its role in thermal protection ofBombyxlarvae and pupae.

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.

scholarly journals Tissue Tropisms and Transstadial Transmission of a Rickettsia Endosymbiont in the Highland Midge, Culicoides impunctatus (Diptera: Ceratopogonidae)

2020 ◽  
Vol 86 (20) ◽  
Author(s):  
Jack Pilgrim ◽  
Stefanos Siozios ◽  
Matthew Baylis ◽  
Gregory D. D. Hurst
Keyword(s):  
Vertical Transmission ◽  
Fat Body ◽  
Germ Line ◽  
Horizontal Transmission ◽  
Follicle Cells ◽  
Biting Midges ◽  
Diverse Range ◽  
Suspensory Ligament ◽  
Transstadial Transmission ◽  
Tissue Tropisms

ABSTRACT Rickettsia is a genus of intracellular bacteria which can manipulate host reproduction and alter sensitivity to natural enemy attack in a diverse range of arthropods. The maintenance of Rickettsia endosymbionts in insect populations can be achieved through both vertical and horizontal transmission routes. For example, the presence of the symbiont in the follicle cells and salivary glands of Bemisia whiteflies allows Belli group Rickettsia transmission via the germ line and plants, respectively. However, the transmission routes of other Rickettsia bacteria, such as those in the Torix group of the genus, remain underexplored. Through fluorescence in situ hybridization (FISH) and transmission electron microscopy (TEM) screening, this study describes the pattern of Torix Rickettsia tissue tropisms in the highland midge, Culicoides impunctatus (Diptera: Ceratopogonidae). Of note is the high intensity of infection of the ovarian suspensory ligament, suggestive of a novel germ line targeting strategy. Additionally, localization of the symbiont in tissues of several developmental stages suggests transstadial transmission is a major route for ensuring maintenance of Rickettsia within C. impunctatus populations. Aside from providing insights into transmission strategies, the presence of Rickettsia bacteria in the fat body of larvae indicates potential host fitness and vector capacity impacts to be investigated in the future. IMPORTANCE Microbial symbionts of disease vectors have garnered recent attention due to their ability to alter vectorial capacity. Their consideration as a means of arbovirus control depends on symbiont vertical transmission, which leads to spread of the bacteria through a population. Previous work has identified a Rickettsia symbiont present in several species of biting midges (Culicoides spp.), which transmit bluetongue and Schmallenberg arboviruses. However, symbiont transmission strategies and host effects remain underexplored. In this study, we describe the presence of Rickettsia in the ovarian suspensory ligament of Culicoides impunctatus. Infection of this organ suggests the connective tissue surrounding developing eggs is important for ensuring vertical transmission of the symbiont in midges and possibly other insects. Additionally, our results indicate Rickettsia localization in the fat body of Culicoides impunctatus. As the arboviruses spread by midges often replicate in the fat body, this location implies possible symbiont-virus interactions to be further investigated.

Studies on ovarian development in tsetse flies (Glossina, Diptera)

Parasitology ◽  
1961 ◽  
Vol 51 (3-4) ◽  
pp. 545-564 ◽  
Author(s):  
D. S. Saunders
Keyword(s):  
Seasonal Variation ◽  
Ovarian Development ◽  
Fat Body ◽  
Fat Content ◽  
The State ◽  
Tsetse Flies ◽  
Pupal Development ◽  
Follicle Size ◽  
The Right ◽  
Egg Follicles

Five species of Glossina (G. morsitans, G. pallidipes, G. austeni, G. brevipalpis and G. palpalis) have ovaries containing two polytrophic ovarioles, each of which contains a single egg follicle. In all these species the right ovary is more highly developed than the left at emergence. This type of ovary is probably common to all species of Glossina.The development of the egg follicles in G. morsitans pupae is described. It is shown that the cycle of development whereby eggs are produced alternately from right and left ovaries is established during pupal development and that some yolk deposition has occurred in follicle A (right ovary) and follicle C (left ovary) before the fly emerges from the puparium.In G. morsitans, it is shown that the size of the egg follicles in newly emerged flies is correlated with the size (R.D.W.) of the fly, larger females having more yolk laid down in their follicles before emergence. This is probably correlated with the state of reserves in the fat body. It is also shown that there is a seasonal variation in follicle size in newly emerged flies, this variation is probably correlated with variations in temperature acting upon wild females during pregnancy and upon the pupae, as temperature is known to affect both size and fat content of wild tsetse flies.

scholarly journals Vertical Transmission of a Drosophila Endosymbiont Via Cooption of the Yolk Transport and Internalization Machinery

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Jeremy K. Herren ◽  
Juan C. Paredes ◽  
Fanny Schüpfer ◽  
Bruno Lemaitre
Keyword(s):  
Vertical Transmission ◽  
Fat Body ◽  
Germ Line ◽  
Ovarian Follicle ◽  
Follicle Cells ◽  
Content Type ◽  
Vector Borne Diseases ◽  
Severe Reduction ◽  
Female Germ Line ◽  
Vector Borne

ABSTRACTSpiroplasmais a diverse bacterial clade that includes many vertically transmitted insect endosymbionts, includingSpiroplasma poulsonii, a natural endosymbiont ofDrosophila melanogaster. These bacteria persist in the hemolymph of their adult host and exhibit efficient vertical transmission from mother to offspring. In this study, we analyzed the mechanism that underlies their vertical transmission, and here we provide strong evidence that these bacteria use the yolk uptake machinery to colonize the germ line. We show thatSpiroplasmareaches the oocyte by passing through the intercellular space surrounding the ovarian follicle cells and is then endocytosed into oocytes within yolk granules during the vitellogenic stages of oogenesis. Mutations that disrupt yolk uptake by oocytes inhibit verticalSpiroplasmatransmission and lead to an accumulation of these bacteria outside the oocyte. Impairment of yolk secretion by the fat body results inSpiroplasmanot reaching the oocyte and a severe reduction of vertical transmission. We propose a model in whichSpiroplasmafirst interacts with yolk in the hemolymph to gain access to the oocyte and then uses the yolk receptor, Yolkless, to be endocytosed into the oocyte. Cooption of the yolk uptake machinery is a powerful strategy for endosymbionts to target the germ line and achieve vertical transmission. This mechanism may apply to other endosymbionts and provides a possible explanation for endosymbiont host specificity.IMPORTANCEMost insect species, including important disease vectors and crop pests, harbor vertically transmitted endosymbiotic bacteria. Studies have shown that many facultative endosymbionts, includingSpiroplasma, confer protection against different classes of parasites on their hosts and therefore are attractive tools for the control of vector-borne diseases. The ability to be efficiently transmitted from females to their offspring is the key feature shaping associations between insects and their inherited endosymbionts, but to date, little is known about the mechanisms involved. In oviparous animals, yolk accumulates in developing eggs and serves to meet the nutritional demands of embryonic development. Here we show thatSpiroplasma coopts the yolk transport and uptake machinery to colonize the germ line and ensure efficient vertical transmission. The uptake of yolk is a female germ line-specific feature and therefore an attractive target for cooption by endosymbionts that need to maintain high-fidelity maternal transmission.

Sign in / Sign up

Export Citation Format

Share Document