scholarly journals Genes from two intermoult puffs in Drosophila virilis polytene chromosomes are differentially transcribed during larval development

Development ◽  
1990 ◽  
Vol 108 (2) ◽  
pp. 261-267
Author(s):  
P. Kress H ◽  
L. Lucka ◽  
U. Swida ◽  
E. Thuroff ◽  
U. Klemm

Genes from two Drosophila virilis intermoult puffs were isolated by microcloning. From puff 16A on the X-chromosome a 2.9 kb DNA fragment was obtained, which hybridizes with three transcripts. Two of them represent the mRNAs for larval glue proteins. They are found in different abundancies in third larval instar salivary glands, but also in minor amounts in midgut and in fat body. In puff 55E on chromosome III two genes were identified. They are transcribed exclusively in salivary glands during all three larval instars. Therefore, their products must be related to another gland-specific function, which is sustained throughout larval life.


Author(s):  
Rahma R. Z. Mahdy ◽  
Shaimaa A. Mo’men ◽  
Marah M. Abd El-Bar ◽  
Emad M. S. Barakat

Abstract Background Insect lipid mobilization and transport are currently under research, especially lipases and lipophorin because of their roles in the production of energy and lipid transport at a flying activity. The present study has been conducted to purify intracellular fat body lipase for the first time, from the last larval instar of Galleria mellonella. Results Purification methods by combination of ammonium sulfate [(NH4)2SO4] precipitation and gel filtration using Sephadex G-100 demonstrated that the amount of protein and the specific activity of fat body lipase were 0.008633 ± 0.000551 mg/ml and 1.5754 ± 0.1042 μmol/min/mg protein, respectively, with a 98.9 fold purity and recovery of 50.81%. Hence, the sephadex G-100 step was more effective in the purification process. SDS-PAGE and zymogram revealed that fat body lipase showed two monomers with molecular weights of 178.8 and 62.6 kDa. Furthermore, biochemical characterization of fat body lipase was carried out through testing its activities against several factors, such as different temperatures, pH ranges, metal ions, and inhibitors ending by determination of their kinetic parameters with the use of p-nitrophenyl butyrate (PNPB) as a substrate. The highest activities of enzyme were determined at the temperature ranges of 35–37 °C and 37–40 °C and pH ranges of 7–9 and 7–10. The partially purified enzyme showed significant stimulation by Ca2+, K+, and Na+ metal ions indicating that fat body lipase is metalloproteinase. Lipase activity was strongly inhibited by some inhibitors; phenylmethylsulfonyl fluoride (PMSF), ethylene-diaminetetractic acid (EDTA), and ethylene glycoltetraacetic acid (EGTA) providing evidence of the presence of serine residue and activation of enzymes by metal ions. Kinetic parameters were 0.316 Umg− 1 Vmax and 301.95 mM Km. Conclusion Considering the purification of fat body lipase from larvae and the usage of some inhibitors especially ion chelating agents, it is suggested to develop a successful control of Galleria mellonella in near future by using lipase inhibitors.



1933 ◽  
Vol s2-76 (301) ◽  
pp. 35-61
Author(s):  
DEV RAJ MEHTA

A general account of the internal reproductive organs and the external genitalia and their development is given. The ‘penis lobes’ develop earlier than the ‘valvae lobes’, and independently of them. The tegumen is the modified ninth tergite. The tenth segment is visibly distinguished into a tergal and sternal part in the pupal stages, and the anal tube passes between the two sclerites. The uncus and the gnathos are dorsal and ventral processes respectively of the tenth segment. The anellus lobes develop as lateral processes of the ninth sternite on either side of the penis. The vasa deferentia during larval life do not extend beyond the eighth abdominal segment and lie in a latero-ventral position. They meet the extensions from the ectodermal ‘ductus ejaculatorius duplex’ during the last larval stadium. From the earliest caterpillar stage there exists a pair of ectodermal ducts formed by the differentiation of the epidermis on the ninth sternite. Towards the end of larval life they divide by constriction to form the accessory glands and the ‘ductus ejaculatory duplex’. At this stage they extend on either side to meet the vasa deferentia. The vesiculae seminales develop by distension from the region of junction between the vasa deferentia and the proximal portion of the ejaculatory duct. The ‘ductus ejaculatorius simplex’ arises as an ectodermal invagination between the pair of ‘penis lobes’ during the final larval instar. It is established that, with the exception of the vasa deferentia, all the remaining elements in the efferent genital system are derived from the ectoderm.



1986 ◽  
Vol 28 (2) ◽  
pp. 180-188 ◽  
Author(s):  
D. G. Bedo

Polytene chromosomes were found in several larval and pupal tissues of the Medfly, Ceratitis capitata, during a search for chromosomes suitable for detailed cytological analysis. Well-banded highly polytene chromosomes, which could be adequately separated and spread, were found in trichogen cells of the spatulate superior orbital bristles of male pupae. These chromosomes proved suitable for full polytene analysis. Thoracic trichogen cells of both male and female pupae also contain useful polytene chromosomes, although they are considerably thinner and thus more difficult to analyze. Contrasting with those in pupal trichogen cells, the chromosomes in the salivary glands, Malphighian tubules, midgut, hindgut, and fat body of larvae and pupae were difficult to prepare because of high levels of ectopic pairing and chromosome fragmentation. In hindgut preparations partial separation of up to three chromosomes was achieved, but in all other tissues no useful chromosome separation was possible. In trichogen polytene cells, five banded chromosomes and a prominent heterochromatic network associated with a nucleolus are found. The mitotic chromosomes respond to C- and Q-banding and silver staining with considerable variation. This is especially so in the X chromosome, which displays an extensive array of bands following both Q-banding and silver staining. Comparison of Q-banded metaphase and polytene chromosomes demonstrates that the five autosomes are represented by conventional polytene chromosomes, while the sex chromosomes are contained in the heterochromatic net, most of which fluoresces strongly. This suggests that the Q-bands of the mitotic X chromosome are replicated to a greater extent than the nonfluorescent material in polytene cells. This investigation shows C. capitata to have excellent cytological material for both polytene and mitotic analysis.Key words: Ceratitis capitata, Medfly, chromosomes (polytene), banding (chromosome).



1991 ◽  
Vol 11 (10) ◽  
pp. 5346-5355
Author(s):  
D D Dubey ◽  
L R Davis ◽  
S A Greenfeder ◽  
L Y Ong ◽  
J G Zhu ◽  
...  

The silent mating-type loci of Saccharomyces cerevisiae, HML and HMR, are flanked by transcriptional silencers that have ARS activity (i.e., they function as replication origins when in plasmids). To test whether these ARS elements are chromosomal origins, we mapped origins near HML (close to the left telomere of chromosome III). Our results indicate that the HML-associated ARS elements either do not function as chromosomal replication origins or do so at a frequency below our detection level, suggesting that replication from a silencer-associated origin in each S phase is not essential for the maintenance of transcriptional repression at HML. Our results also imply that the ability of a DNA fragment to function as an ARS element in a plasmid does not ensure its ability to function as an efficient chromosomal replication origin. Telomere proximity is not responsible for inactivating these ARS elements, because they are not detectably functional as chromosomal origins even in genetically modified strains in which they are far from the telomere.



Micron ◽  
2020 ◽  
Vol 137 ◽  
pp. 102915
Author(s):  
Magdalena Rost-Roszkowska ◽  
Izabela Poprawa ◽  
Łukasz Chajec ◽  
Alina Chachulska-Żymełka ◽  
Małgorzata Leśniewska ◽  
...  


2015 ◽  
Vol 112 (31) ◽  
pp. E4226-E4235 ◽  
Author(s):  
Takaaki Daimon ◽  
Miwa Uchibori ◽  
Hajime Nakao ◽  
Hideki Sezutsu ◽  
Tetsuro Shinoda

Insect juvenile hormones (JHs) prevent precocious metamorphosis and allow larvae to undergo multiple rounds of status quo molts. However, the roles of JHs during the embryonic and very early larval stages have not been fully understood. We generated and characterized knockout silkworms (Bombyx mori) with null mutations in JH biosynthesis or JH receptor genes using genome-editing tools. We found that embryonic growth and morphogenesis are largely independent of JHs in Bombyx and that, even in the absence of JHs or JH signaling, pupal characters are not formed in first- or second-instar larvae, and precocious metamorphosis is induced after the second instar at the earliest. We also show by mosaic analysis that a pupal specifier gene broad, which is dramatically up-regulated in the late stage of the last larval instar, is essential for pupal commitment in the epidermis. Importantly, the mRNA expression level of broad, which is thought to be repressed by JHs, remained at very low basal levels during the early larval instars of JH-deficient or JH signaling-deficient knockouts. Therefore, our study suggests that the long-accepted paradigm that JHs maintain the juvenile status throughout larval life should be revised because the larval status can be maintained by a JH-independent mechanism in very early larval instars. We propose that the lack of competence for metamorphosis during the early larval stages may result from the absence of an unidentified broad-inducing factor, i.e., a competence factor.



Genome ◽  
1991 ◽  
Vol 34 (2) ◽  
pp. 215-219 ◽  
Author(s):  
A. Zacharopoulou ◽  
K. Bourtzis ◽  
Ph. Kerremans

The banding patterns of polytene chromosomes in different tissues of the Mediterranean fruit fly, Ceratitis capitata, vary to such an extent that homologous chromosomes cannot be recognised. However, analyses of autosomal breakpoints in several translocation strains allowed chromosomes from the two tissues to be aligned despite their difference in banding pattern. These results were discussed, considering the different hypotheses of the origin and biological significance of polytene chromosome bands.Key words: polytene chromosomes, salivary gland chromosomes, orbital bristle trichogen cell chromosomes, Ceratitis capitata.



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