The induction of lysosomal enzyme activity in the fat body of Calliphora erythrocephala: Changes in the internal environment

Pelt-Verkuil, E. van

doi:10.1016/0022-1910(80)90048-7

Cited by 17 publications

(2 citation statements)

References 33 publications

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“…This situation may be caused by factors missing from the hemolymph. Hydrolytic enzymes which are important for initiation of destruction are mostly made by fat bodies and are released into the hemolymph (Van Pelt-Verkuil, 1979a, 1979b. Initially degenerated basal lamina is then attacked and the tissue phagoeytosed by hemocytes, as was observed in vivo by yon Gaudecker (1972) and us (not shown).…”

Section: Discussionmentioning

confidence: 67%

Ultrastructural changes of Drosophila larval and prepupal salivary glands cultured in vitro with ecdysone

Farkas

Sutáková

1998

In Vitro Cell.Dev.Biol.-Animal

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Alterations in the ultrastructure of in vitro cultured larval salivary glands of Drosophila melanogaster in response to the steroid hormone ecdysone were studied in relation to complex changes in puffing patterns. We found that the changes in the fine structure of cultured glands reflected progression of the puffing pattern, and they paralleled those seen in vivo. We observed that glue secretion by exocytosis, the main function of salivary glands, took place between puff stage 5 (PS5) and PS7. Glue could not be expectorated under culture conditions but was slowly released from the lumen through a duct into the medium. After the cultured glands reached PS13/PS14, further progress of puffing and fine structural alterations required that the ecdysteroid titer be transiently extremely low or absent. Under in vitro conditions we did not observe the putative new secretory program(s) described for glands in vivo after PS12. However, ultrastructural changes which unambiguously indicated that an autohistolytic process had begun in vitro started to appear after PS17. Many salivary gland cells developed numerous features of progressive self-degradation between PS18 and PS21. Actual degradation of salivary glands in vivo seemed to be rapid, but in vitro degradation was never completed, probably due to a lack of exogenous factors from the hemolymph. Manipulations of ecdysone titer in vitro in the culture medium, known during the larval puffing cycle to cause premature induction of developmentally specific puffing patterns, did not affect the normal development of ultrastructural features of the cytoplasm and nucleus.

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Section: Discussionmentioning

confidence: 67%

Ultrastructural changes of Drosophila larval and prepupal salivary glands cultured in vitro with ecdysone

Farkas

Sutáková

1998

In Vitro Cell.Dev.Biol.-Animal

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“…[53][54][55][56][57] 20-OHE also has a strong influence in the regulation of the synthesis and activity of the lysosomal enzymes. 26,36,[58][59][60][61] The main aim of the present work was to select and identify autophagy-related genes in Drosophila melanogaster. Late larval lethal strains generated by P-element mutagenesis were screened to find mutants showing defects in the formation of autophagic structures (acidic granules identified by light and electron microscopy) in the larval fat body cells.…”

Section: Discussionmentioning

confidence: 99%

SNF4Aγ, the Drosophila AMPK γ subunit is required for regulation of developmental and stress-induced autophagy

et al. 2008

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In holometabolous insects including Drosophila melanogaster a wave of autophagy triggered by 20-hydroxyecdysone is observed in the larval tissues during the third larval stage of metamorphosis. We used this model system to study the genetic regulation of autophagy. We performed a genetic screen to select P-element insertions that affect autophagy in the larval fat body. Light and electron microscopy of one of the isolated mutants (l(3)S005042) revealed the absence of autophagic vesicles in their fat body cells during the third larval stage. We show that formation of autophagic vesicles cannot be induced by 20-hydroxyecdysone in the tissues of mutant flies and represent evidence demonstrating that the failure to form autophagic vesicles is due to the insertion of a P-element into the gene coding SNF4Aγ, the Drosophila homologue of the AMPK (AMP-activated protein kinase) γ subunit. The ability to form autophagic vesicles (wild-type phenotype) can be restored by remobilization of the P-element in the mutant. Silencing of SNF4Aγ by RNAi suppresses autophagic vesicle formation in wildtype flies. We raised an antibody against SNF4Aγ and showed that this gene product is constitutively present in the wild-type larval tissues during postembryonal development. SNF4Aγ is nearly absent from the cells of homozygous mutants. SNF4Aγ translocates into the nuclei of fat body cells at the onset of the wandering stage concurrently with the beginning of the autophagic process. Our results demonstrate that SNF4Aγ has an essential role in the regulation of autophagy in Drosophila larval fat body cells.

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Changes of acid phosphatase content and activity in the fat body and the hemolymph of the flesh flyNeobellieria (sarcophaga) bullata during metamorphosis

Csikós

Sass

1997

Arch. Insect Biochem. Physiol.

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Changes in the specific and total activity of the lysosomal marker enzyme acid phosphatase (Acph) and in the amount of enzyme protein were examined in the fat body and the hemolymph from the last larval molt to the larval‐pupal apolysis. The specific activity showed minor changes during the last larval period. In contrast, the total activity of the enzyme was low during the feeding period and higher during the wandering stage and strikingly increased at the time of puparium formation. We purified a protein having para‐nitrophenyl phosphate phosphatase (Acph) activity and raised antisera against it. The amount of Acph protein in the fat body and hemolymph was examined using an ELISA. The specific Acph content showed little variation, but the total amount of the enzyme protein showed a stepwise increase in both organs during last larval stage and was markedly elevated in the pupal stage in the fat body. In contrast, a considerable decrease in the amount of Acph protein was observed in the hemolymph during this period. These data were in agreement with immunohistochemical observations showing an accumulation of the enzyme protein in fat body cells during the prepupal stage with a concomitant disappearance of the enzyme from the hemolymph. Inhibition of ecdysteroid secretion by water stress prevented the changes both in total enzyme activity and in the amount of Acph protein. However, Acph protein content and enzyme activity could be restored when the water stress was followed by a 20‐hydroxyecdysone (20‐HE) treatment. Taken together, our data show that Acph is secreted by fat body cells into the hemolymph during the larval stage, where it is stored in an inactive form. Increase in the 20‐HE titer at the end of last larval stage reverses this process, and the enzyme is taken up by the fat body cells, where it becomes activated and appears in auto‐ and heterophagic vacuoles. Arch. Insect Biochem. Physiol. 34:369–390, 1997. © 1997 Wiley‐Liss, Inc.

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The induction of lysosomal enzyme activity in the fat body of Calliphora erythrocephala: Changes in the internal environment

Cited by 17 publications

References 33 publications

Ultrastructural changes of Drosophila larval and prepupal salivary glands cultured in vitro with ecdysone

Ultrastructural changes of Drosophila larval and prepupal salivary glands cultured in vitro with ecdysone

SNF4Aγ, the Drosophila AMPK γ subunit is required for regulation of developmental and stress-induced autophagy

Changes of acid phosphatase content and activity in the fat body and the hemolymph of the flesh flyNeobellieria (sarcophaga) bullata during metamorphosis

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