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Localization of metals in cells of pterygote insects
Author(s) -
BallanDufrançais Christiane
Publication year - 2002
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.10041
Subject(s) - golgi apparatus , malpighian tubule system , endoplasmic reticulum , cadmium , cockroach , cytoplasm , chemistry , hemolymph , metallothionein , biophysics , insect , microbiology and biotechnology , integument , biology , biochemistry , anatomy , botany , ecology , midgut , organic chemistry , larva
Insects maintain the equilibrium of their internal milieu by diffusion mechanisms, but more frequently by a substantial storage of metals in the cells of numerous organs: digestive tract, Malpighian tubules, fat body, integument, and genital organs. This storage implies the precipitation, of numerous cations (Ca, Mg, K, Mn, Fe, Zn, Cu) in a structure called the spherocrystal, which originates from the endoplasmic reticulum–Golgi complex: elements precipitate on a glycosaminoglycan nucleus in thin peripheral strata. Some spherocrystals contain exclusively mineral compounds, frequently phosphates, whereas others may contain organic compounds such as urates. In some species mineralized lysosomes store Ca, Fe, Zn, and Cu. When fed additional metals found in the environment, insects such as cockroach and ant are able to stay alive and to trap the metals (Cd or Pb, for example) in the peripheral strata of spherocrystals; the cytoplasm is not altered. It seems that these insects are able to resist exposures to high levels of toxic metals. The lysosomes are able to retain toxic heavy metals (Cd or Hg, for example) within metallothionein‐like proteins. Microsc. Res. Tech. 56:403–420, 2002. © 2002 Wiley‐Liss, Inc.