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|Title:||Extracellular organization of an insect mucus elaborated by Malpighian tubules|
|Author:||Mello, Maria Luiza S.|
|Abstract:||The extracellular organization of the mucus secreted by the Malpighian tubules of the bumblebee , Bombus atratus, was studied in ruthenium red (RR) stained preparations observed with an electron microscope. Slight filaments predominantly parallel to the long axis of the microvilli were found to interconnect dense bodies among themselves. Based on data for vertebrate extracellular matrices andgoblet cell mucus, the filaments of the Malpighian tubule mucus are assumed to be composed of proteoglycans, acid glycosaminoglycan (AGAG) macromolecules possibly being collapsed over the polypeptide chain. The small dense bodies, on the other hand, are considered to be glycoprotein complexes encircled with proteoglycans . The very large dense bodies are urate crystals associated with a strongly RR-positive material, possibly of a proteoglycan nature. These data are also in agreement with a previous report on quantitative polarization microscopy and histochemistry for the same material. Apart from the presence of urate formations, the ultrastructure of the Malpighian tubule mucus has many similarities with that of vertebrate goblet cells and that of unpacked extracellular matrices. Laminated excretory corpuscles were found only in luminal areas free from mucus and urates|
Túbulos de Malpighi
|Citation:||Cellular And Molecular Biology. Cellular & Molecular Biology, v. 30, n. 4, n. 353, n. 356, 1984.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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