Related Experiment Video
Updated: May 8, 2026
09:47
Microdissection of Black Widow Spider Silk-producing Glands
Published on: January 11, 2011
15.8K
Asynchronous programmed cell death occurrence in the silk glands at pupation (Bombyx mori)
Haoyi Gu1, Jialu Cheng1, Hongbin Zou1
1School of Life Sciences, Soochow University, Suzhou, Jiangsu Province, China.
Insect Science
|August 28, 2025
Summary
Silkworm silk glands undergo programmed cell death (PCD) during pupation. Delayed inositol-1,4,5-trisphosphate receptor expression in the anterior silk gland causes asynchronous PCD, impacting insect metamorphosis.
Area of Science:
- Cell Biology
- Developmental Biology
- Insect Physiology
Background:
- Silk glands are vital for silk production but degenerate via programmed cell death (PCD) at pupation.
- The distinct roles of anterior silk gland (ASG) and middle silk gland (MSG) suggest differential PCD mechanisms, which remain unclear.
Purpose of the Study:
- To investigate the occurrence and regulation of autophagy and apoptosis in the ASG and MSG during silkworm metamorphosis.
- To elucidate the role of calcium (Ca2+) homeostasis and specific proteins in the asynchronous PCD of silk gland sections.
Main Methods:
- Comparative analysis of autophagy and apoptosis markers in ASG and MSG from mature silkworms to day 1 pupae.
- Monitoring of Ca2+ levels and key protein expression, including inositol-1,4,5-trisphosphate receptor (IP3R) and autophagy-related protein 5 (ATG5).
- Utilizing IP3R inhibitors to assess their effect on apoptosis.
Main Results:
- Early metamorphosis shows high autophagy and low apoptosis, with a shift to apoptosis after Ca2+ levels peak.
- The ASG exhibits significant apoptosis 24 hours later than the MSG, coinciding with peak Ca2+ levels.
- Delayed IP3R expression in ASG leads to slower Ca2+ release, delayed ATG5 cleavage, and consequently, delayed apoptosis onset.
Conclusions:
- Delayed IP3R expression in the ASG regulates Ca2+ release and calpain-mediated ATG5 cleavage, causing asynchronous PCD between silk gland regions.
- This study reveals distinct PCD regulation in secretory (MSG) versus non-secretory (ASG) tissues.
- Findings offer new insights into tissue-specific degradation during insect metamorphosis.
Related Concept Videos
01:20Binary Fission
Fission is the division of a single entity into two or more parts, which regenerate into separate entities that resemble the original. Organisms in the Archaea and Bacteria domains reproduce using binary fission, in which a parent cell splits into two parts that can each grow to the size of the original parent cell. This asexual method of reproduction produces cells that are all genetically identical.
01:30Overview of Cell Death
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
01:30Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
01:18Autophagic Cell Death
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
01:26Binary Fission
Binary fission is the primary mode of asexual reproduction in prokaryotes, such as bacteria. It results in the production of two genetically identical daughter cells. This highly efficient process ensures the rapid propagation of bacterial populations under favorable conditions and involves coordinated cellular and molecular events.DNA Replication and SeparationThe process begins with the replication of the bacterial chromosome. The circular DNA molecule unwinds at a specific origin of...