Cold-stress induced formation of calcium and phosphorous rich chloragocyte granules (chloragosomes) in the earthworm Eisenia fetida.
The cytochemical and functional characteristics of chloragocytes of both 'control' and cold-stressed Eisenia fetida were examined. Flow cytometry revealed the heterogeneity of chloragocytes: the first group was characterized by low, the second one by high acid phosphatase (AcP) content. In 'control' animals the former, in cold-stressed ones the latter type were the dominant form. The elevated AcP-activity correlated with the accumulation of autophagic vacuoles (AVs) in chloragocytes. Both AVs and all small chloragosomes showed high AcP activity, while most of the large chloragosomes did not display any. Most 'control' granules (0.75-1.25 μm) contained high amounts of Ca and P, with less and variable quantities of S, Cl, K, Fe and Zn. Small chloragosomes with low Ca and P concentrations were seldom found. In cold-stressed animals the number of small granules (0.25-0.75 μm) increased up to 40% of total population. Their Ca and P contents were significantly lower; S and Fe concentrations were higher than those of large chloragosomes (1.0-1.5 μm). Our results prove that the formation and elemental composition of chloragosomes can be influenced by environmental stressors and suggest that the mature chloragosomes are tertiary lysosomes and their formation is coupled to autophagocytosis.
Department of General Zoology, Faculty of Sciences, University of Pécs, 7624 Pécs, Ifjúság u. 6, Hungary. drmolnarl@gmail.com
László
L
Molnár
Péter
P
Engelmann
Ildikó
I
Somogyi
Levente László
LL
Mácsik
Edit
E
Pollák
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001808:Blood Vessels / Q000166:cytology*; D002118:Calcium / Q000378:metabolism*; D003080:Cold Temperature; D003594:Cytoplasmic Granules / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D004064:Digestive System / Q000098:blood supply; D009835:Oligochaeta / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D053140:Organelle Shape; D010758:Phosphorus / Q000378:metabolism*; D013312:Stress, Physiological
D010758:Phosphorus; D000135:Acid Phosphatase; D002118:Calcium