scholarly journals Ein invasives Neoplasma aus embryonalen Zellen von Drosophila melanogaster in Dauerkultur in vivo

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 347-375
Author(s):  
Hans-Peter Hauri
Keyword(s):  
Drosophila Melanogaster ◽  
Intestinal Tract ◽  
Fat Body ◽  
Embryonic Cells ◽  
Cultivation Temperature ◽  
Virus Like Particles ◽  
Egg Deposition ◽  
Abnormal Cells ◽  
Cytoplasmic Processes

An invasive neoplasm from embryonic cells of Drosophila melanogaster cultured permanently in vivo The neoplasm H 126, obtained from the posterior half of a 6 ± 1-h-old embryo of Drosophila melanogaster, was cultivated in adult female flies over more than 120 transfer generations (more than 4 years). Four sub-lines were derived from it. The neoplasm H 126 invades the ovaries of the host flies, whereas the intestinal tract and the fat body are only surrounded very tightly, but not invaded by these abnormal cells. The neoplasm is lethal to the host 8–14 days after implantation into the abdomen (cultivation temperature: 25 °C). Egg deposition of neoplasm-bearing hosts decreases 5 days after abdominal implantation. After 4 years of cultivation the sub-lines differ specifically from one another in their chromosomal content; however, all of them show a karyotype near tetraploidy. Ultrastructural features of these neoplasm cells are: (a) the nearly complete absence of membrane specializations correlated with weak cell adhesion, (b) the abundance of cytoplasmic processes and (c) 36 nm virus-like particles in the nucleus and in the cytoplasm. Invasiveness, alterations of the karyotype, the origin of the neoplasm H 126, and the presence of virus-like particles are discussed.

Recent findings on oogenesis of Drosophila melanogaster

Development ◽  
1977 ◽  
Vol 38 (1) ◽  
pp. 125-138
Author(s):  
F. Giorgi ◽  
J. Jacob
Keyword(s):  
Drosophila Melanogaster ◽  
Fat Body ◽  
Radioactive Tracer ◽  
Superficial Layer ◽  
Ruthenium Red ◽  
Time Interval ◽  
Intracellular Location ◽  
Short Time

Vitellogenic ovaries from Drosophila melanogaster flies have been exposed, either in in vivo or in vitro conditions, to various extracellular tracers in an attempt to determine the possible route of entry of the yolk precursors. Ruthenium red and lanthanum nitrate have been shown to gain access to the oocyte surface by initially passing through the intercellular spaces of the follicle layer. Both these tracers, however, never attain an intracellular location within any of the cells forming the ovarian chamber. Colloidal Thorotrast when injected into adult females has never been detected within any of the ovarian chambers examined, irrespective of their stage. Vitellogenic oocytes exposed to peroxidase in in vivo conditions exhibit the oolemma and all the structural elements present in the cortical ooplasm well labelled within a very short time after the injection. Moreover, with gradually increasing exposure times to peroxidase, the labelled yolk platelets increase progressively in number. At each time interval after the injection, the label over the yolk platelets remains restricted to the superficial layer and never gets into the associated body. The pattern of tritiated lysine incorporation into vitellogenic oocytes has been studied over a period of 20 h. A few hours after injection of the radioactive tracer, the silver grains located over the ooplasm appear distributed at random. A predominant labelling of the yolk platelets as compared to the rest of the ooplasm, becomes evident only with a 6 h delay since the time of injection. When analysed by electrophoresis and isolectrofocusing, the vitellogenic ovary is seen to exhibit a number of protein bands which are common to those of other tissues as, for instance, haemolymph and fat body. The evidence obtained in the present study is discussed in relation to the hypothesis of an extraovarian origin of the yolk precursors and their sequestration into forming yolk platelets.

Cell cycle progression and cell division are sensitive to hypoxia in Drosophila melanogaster embryos

2001 ◽  
Vol 280 (5) ◽  
pp. R1555-R1563 ◽  
Author(s):  
Robert M. Douglas ◽  
Tian Xu ◽  
Gabriel G. Haddad
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Immunoblot Analysis ◽  
Embryonic Cell ◽  
Cell Cycle Checkpoints ◽  
Cycle Phase ◽  
Embryonic Cells

We and others recently demonstrated that Drosophila melanogaster embryos arrest development and embryonic cells cease dividing when they are deprived of O2. To further characterize the behavior of these embryos in response to O2 deprivation and to define the O2-sensitive checkpoints in the cell cycle, embryos undergoing nuclear cycles 3–13 were subjected to O2deprivation and examined by confocal microscopy under control, hypoxic, and reoxygenation conditions. In vivo, real-time analysis of embryos carrying green fluorescent protein-kinesin demonstrated that cells arrest at two major points of the cell cycle, either at the interphase (before DNA duplication) or at metaphase, depending on the cell cycle phase at which O2 deprivation was induced. Immunoblot analysis of embryos whose cell divisions are synchronized by inducible String (cdc25 homolog) demonstrated that cyclin B was degraded during low O2 conditions in interphase-arrested embryos but not in those arrested in metaphase. Embryos resumed cell cycle activity within ∼20 min of reoxygenation, with very little apparent change in cell cycle kinetics. We conclude that there are specific points during the embryonic cell cycle that are sensitive to the O2 level in D. melanogaster. Given the fact that O2deprivation also influences the growth and development of other species, we suggest that similar hypoxia-sensitive cell cycle checkpoints may also exist in mammalian cells.

scholarly journals The ecdysone response enhancer of the Fbp1 gene of Drosophila melanogaster is a direct target for the EcR/USP nuclear receptor.

1994 ◽  
Vol 14 (7) ◽  
pp. 4465-4474 ◽  
Author(s):  
C Antoniewski ◽  
M Laval ◽  
A Dahan ◽  
J A Lepesant
Keyword(s):  
Drosophila Melanogaster ◽  
Binding Site ◽  
Fat Body ◽  
Sequence Similarity ◽  
High Concentration ◽  
Direct Role ◽  
Palindromic Structure ◽  
Fbp1 Gene

The transcription of the Drosophila melanogaster Fbp1 gene is induced by the steroid hormone 20-hydroxyecdysone and restricted to the late-third-instar fat body tissue. In a previous study we showed that the -68 to -138 region relative to the transcription start site acts as an ecdysone-dependent third-instar fat body-specific enhancer in a transgenic assay. Here we report that seven nucleoprotein complexes are formed in vitro on this enhancer when a nuclear extract from late-third-instar fat body is used in a gel shift assay. Accurate mapping of the binding sites of the complexes revealed a remarkably symmetrical organization. Using specific antibodies, one of the complexes was identified as a heterodimer consisting of the ecdysone receptor (EcR) and Ultraspiracle (USP) proteins. The binding site of the heterodimer as defined by mutagenesis and methylation interference experiments bears strong sequence similarity to the canonical hsp27 ecdysone response element, including an imperfect palindromic structure. The two elements diverge at three positions in both half-sites, indicating that the structure of an active EcR/USP binding site allows considerable sequence variations. In vivo footprinting experiments using ligation-mediated PCR and wild-type or ecdysteroid-deficient larvae show that occupancy of the Fbp1 EcR/USP binding site and adjacent region is dependent on a high concentration of ecdysteroids. These results provide strong evidence for a direct role of the EcR/USP heterodimer in driving gene expression in response to changes of the ecdysteroid titer during Drosophila larval development.

scholarly journals Co-option of immune effectors by the hormonal signalling system triggering metamorphosis in Drosophila melanogaster

PLoS Genetics ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. e1009916
Author(s):  
Catarina Nunes ◽  
Takashi Koyama ◽  
Élio Sucena
Keyword(s):  
Drosophila Melanogaster ◽  
Fat Body ◽  
Developmental Regulation ◽  
Bacterial Load ◽  
Systemic Effect ◽  
Dependent Manner ◽  
Downstream Target ◽  
Local Responses ◽  
Insect Metamorphosis

Insect metamorphosis is triggered by the production, secretion and degradation of 20-hydroxyecdysone (ecdysone). In addition to its role in developmental regulation, increasing evidence suggests that ecdysone is involved in innate immunity processes, such as phagocytosis and the induction of antimicrobial peptide (AMP) production. AMP regulation includes systemic responses as well as local responses at surface epithelia that contact with the external environment. At pupariation, Drosophila melanogaster increases dramatically the expression of three AMP genes, drosomycin (drs), drosomycin-like 2 (drsl2) and drosomycin-like 5 (drsl5). We show that the systemic action of drs at pupariation is dependent on ecdysone signalling in the fat body and operates via the ecdysone downstream target, Broad. In parallel, ecdysone also regulates local responses, specifically through the activation of drsl2 expression in the gut. Finally, we confirm the relevance of this ecdysone dependent AMP expression for the control of bacterial load by showing that flies lacking drs expression in the fat body have higher bacterial persistence over metamorphosis. In contrast, local responses may be redundant with the systemic effect of drs since reduction of ecdysone signalling or of drsl2 expression has no measurable negative effect on bacterial load control in the pupa. Together, our data emphasize the importance of the association between ecdysone signalling and immunity using in vivo studies and establish a new role for ecdysone at pupariation, which impacts developmental success by regulating the immune system in a stage-dependent manner. We speculate that this co-option of immune effectors by the hormonal system may constitute an anticipatory mechanism to control bacterial numbers in the pupa, at the core of metamorphosis evolution.

scholarly journals The origin of postembryonic neuroblasts in the ventral nerve cord of Drosophila melanogaster

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 79-88 ◽  
Author(s):  
A. Prokop ◽  
G.M. Technau
Keyword(s):  
Drosophila Melanogaster ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Precursor Cells ◽  
Embryonic Cells ◽  
Gastrula Stage ◽  
Larval Stages ◽  
Single Precursor ◽  
Early Gastrula

Embryonic and postembryonic neuroblasts in the thoracic ventral nerve cord of Drosophila melanogaster have the same origin. We have traced the development of threefold-labelled single precursor cells from the early gastrula stage to late larval stages. The technique allows in the same individual monitoring of progeny cells at embryonic stages (in vivo) and differentially staining embryonic and postembryonic progeny within the resulting neural clone at late postembryonic stages. The analysis reveals that postembryonic cells always appear together with embryonic cells in one clone. Furthermore, BrdU labelling suggests that the embryonic neuroblast itself rather than one of its progeny resumes proliferation as a postembryonic neuroblast. A second type of clone consists of embryonic progeny only.

scholarly journals In vivo transcriptional analysis of the TATA-less promoter of the Drosophila melanogaster vermilion gene

1992 ◽  
Vol 12 (10) ◽  
pp. 4571-4577
Author(s):  
Y W Fridell ◽  
L L Searles
Keyword(s):  
Drosophila Melanogaster ◽  
Transcription Start Site ◽  
Fat Body ◽  
Germ Line ◽  
Transcriptional Analysis ◽  
Start Site ◽  
Transcription Start ◽  
Tata Element ◽  
Type V

Transcriptional regulation of the TATA-less promoter of the Drosophila melanogaster vermilion (v) gene was investigated. Developmental Northern (RNA) blot analysis showed that v transcripts accumulate during late embryo, larval, and adult stages. Sequences that control expression in adults were delineated by analyzing a series of 5' and 3' deletion constructions after germ line transformation. These studies defined two regions, -300 to -600 and -60 to -160, relative to the major transcription start site, as important for maximal levels of expression. Analysis of transformants bearing v-lacZ promoter fusions showed that larval expression is fat body specific and that expression depends on sequences located between +19 and +36 downstream of transcription start site. This downstream element can be functionally replaced by a TATA box in vivo. Furthermore, when added to the wild-type v promoter, a TATA element augments the level of v transcription by three- to fivefold.

scholarly journals Iron sequestration by transferrin 1 mediates nutritional immunity in Drosophila melanogaster

2020 ◽  
Vol 117 (13) ◽  
pp. 7317-7325 ◽  
Author(s):  
Igor Iatsenko ◽  
Alice Marra ◽  
Jean-Philippe Boquete ◽  
Jasquelin Peña ◽  
Bruno Lemaitre
Keyword(s):  
Drosophila Melanogaster ◽  
Defense Mechanism ◽  
Fat Body ◽  
Immune Defense ◽  
In Vivo Model ◽  
Nutritional Immunity ◽  
Iron Sequestration

Iron sequestration is a recognized innate immune mechanism against invading pathogens mediated by iron-binding proteins called transferrins. Despite many studies on antimicrobial activity of transferrins in vitro, their specific in vivo functions are poorly understood. Here we use Drosophila melanogaster as an in vivo model to investigate the role of transferrins in host defense. We find that systemic infections with a variety of pathogens trigger a hypoferremic response in flies, namely, iron withdrawal from the hemolymph and accumulation in the fat body. Notably, this hypoferremia to infection requires Drosophila nuclear factor κB (NF-κB) immune pathways, Toll and Imd, revealing that these pathways also mediate nutritional immunity in flies. Next, we show that the iron transporter Tsf1 is induced by infections downstream of the Toll and Imd pathways and is necessary for iron relocation from the hemolymph to the fat body. Consistent with elevated iron levels in the hemolymph, Tsf1 mutants exhibited increased susceptibility to Pseudomonas bacteria and Mucorales fungi, which could be rescued by chemical chelation of iron. Furthermore, using siderophore-deficient Pseudomonas aeruginosa, we discover that the siderophore pyoverdine is necessary for pathogenesis in wild-type flies, but it becomes dispensable in Tsf1 mutants due to excessive iron present in the hemolymph of these flies. As such, our study reveals that, similar to mammals, Drosophila uses iron limitation as an immune defense mechanism mediated by conserved iron-transporting proteins transferrins. Our in vivo work, together with accumulating in vitro studies, supports the immune role of insect transferrins against infections via an iron withholding strategy.

scholarly journals Signal peptides and signal peptidase in Drosophila melanogaster.

1980 ◽  
Vol 87 (2) ◽  
pp. 516-520 ◽  
Author(s):  
M D Brennan ◽  
T G Warren ◽  
A P Mahowald
Keyword(s):  
Drosophila Melanogaster ◽  
Fat Body ◽  
Signal Sequence ◽  
Polyacrylamide Gel Electrophoresis ◽  
Signal Peptidase ◽  
Free System ◽  
Molecular Weights ◽  
Sequence Recognition ◽  
Microsomal Membranes

Translation of poly(A)-containing RNA from the female fat body of Drosophila melanogaster in a rabbit reticulocyte cell-free system results in the synthesis of previtellogenin polypeptides (PVs) having higher apparent molecular weights (46,000 and 45,000) than the forms seen after an in vivo pulse labeling. However, when this RNA is translated in the presence of EDTA-stripped microsomal membranes from the dog pancreas, vitellogenin precursors are produced that, upon SDS-polyacrylamide gel electrophoresis, comigrate with the in vivo forms (apparent molecular weights, 45,000 and 44,000). These processed forms are sequestered within the microsomal lumen, as evidenced by their insensitivity to trypsin digestion. Neither processing nor sequestration occur posttranslationally. In addition, a microsomal membrane fraction derived from Drosophila embryos is able to cotranslationally process the PVs as well as a murine pre-light chain IgG. These observations support a signal-mediated mode of secretion in Drosophila, and suggest that signal sequence recognition and signal peptidase activities are conserved even between mammalian and insect systems.

The ecdysone response enhancer of the Fbp1 gene of Drosophila melanogaster is a direct target for the EcR/USP nuclear receptor

1994 ◽  
Vol 14 (7) ◽  
pp. 4465-4474
Author(s):  
C Antoniewski ◽  
M Laval ◽  
A Dahan ◽  
J A Lepesant
Keyword(s):  
Drosophila Melanogaster ◽  
Binding Site ◽  
Fat Body ◽  
Sequence Similarity ◽  
High Concentration ◽  
Direct Role ◽  
Palindromic Structure ◽  
Fbp1 Gene

The transcription of the Drosophila melanogaster Fbp1 gene is induced by the steroid hormone 20-hydroxyecdysone and restricted to the late-third-instar fat body tissue. In a previous study we showed that the -68 to -138 region relative to the transcription start site acts as an ecdysone-dependent third-instar fat body-specific enhancer in a transgenic assay. Here we report that seven nucleoprotein complexes are formed in vitro on this enhancer when a nuclear extract from late-third-instar fat body is used in a gel shift assay. Accurate mapping of the binding sites of the complexes revealed a remarkably symmetrical organization. Using specific antibodies, one of the complexes was identified as a heterodimer consisting of the ecdysone receptor (EcR) and Ultraspiracle (USP) proteins. The binding site of the heterodimer as defined by mutagenesis and methylation interference experiments bears strong sequence similarity to the canonical hsp27 ecdysone response element, including an imperfect palindromic structure. The two elements diverge at three positions in both half-sites, indicating that the structure of an active EcR/USP binding site allows considerable sequence variations. In vivo footprinting experiments using ligation-mediated PCR and wild-type or ecdysteroid-deficient larvae show that occupancy of the Fbp1 EcR/USP binding site and adjacent region is dependent on a high concentration of ecdysteroids. These results provide strong evidence for a direct role of the EcR/USP heterodimer in driving gene expression in response to changes of the ecdysteroid titer during Drosophila larval development.

scholarly journals Functional fat body proteomics and gene targeting reveal in vivo functions of Drosophila melanogaster α-Esterase-7

2012 ◽  
Vol 42 (3) ◽  
pp. 220-229 ◽  
Author(s):  
Ruth Birner-Gruenberger ◽  
Iris Bickmeyer ◽  
Julia Lange ◽  
Philip Hehlert ◽  
Albin Hermetter ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Targeting ◽  
Fat Body
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