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Metabolic events during programmed cell death in insect labial glands
R Halaby1, Z Zakeri, R A Lockshin
1Department of Biology, Queens College and Graduate Center of City University of New York, Flushing 11367, USA.
Biochemistry and Cell Biology = Biochimie Et Biologie Cellulaire
|November 1, 1994
Summary
The Manduca sexta labial gland undergoes programmed cell death during pupation. Metabolic changes, including increased lysosomal activity and autophagic vacuole formation, precede cell collapse, while energy levels remain stable until late stages.
Area of Science:
- Developmental Biology
- Cell Biology
- Insect Physiology
Background:
- The labial gland of Manduca sexta offers a model for synchronous programmed cell death.
- Previous studies indicated a decline in protein synthesis during gland degeneration.
Purpose of the Study:
- To investigate metabolic alterations in dying Manduca sexta labial gland cells.
- To understand the relationship between cellular metabolism and programmed cell death.
Main Methods:
- Monitoring adenosine triphosphate (ATP) levels for energy status.
- Assessing mitochondrial respiration via tetrazolium bromide reduction.
- Measuring acid phosphatase activity for lysosomal function.
- Analyzing cyclic nucleotide and inositol triphosphate concentrations for signaling pathways.
Main Results:
- Protein synthesis decreased sharply at day 0.
- ATP levels and mitochondrial respiration remained stable until day 3.
- Lysosomal acid phosphatase activity increased during early metamorphosis.
- Cytoplasmic destruction occurred via autophagic vacuoles; signaling molecule changes were modest and late.
Conclusions:
- Cellular energy stores and mitochondrial function are maintained until late in the programmed cell death process of the Manduca sexta labial gland.
- Lysosomal activation and autophagy play significant roles in the degeneration of the labial gland tissue.