Production of specific-protein secretion granules by fat body cells of the blowfly, Calliphora erythrocephala

1978 ◽  
Vol 193 (1) ◽  
Author(s):  
Ellen Thomsen ◽  
Mathias Thomsen
Keyword(s):  
Protein Secretion ◽  
Fat Body ◽  
Specific Protein ◽  
Calliphora Erythrocephala ◽  
Secretion Granules

Influence of Neurosecretory Cells and of Corpus Allatum on Intestinal Protease Activity in the Adult Calliphora Erythrocephala MEIG

1963 ◽  
Vol 40 (2) ◽  
pp. 301-321
Author(s):  
ELLEN THOMSEN ◽  
IB MØLLER
Keyword(s):  
Protein Synthesis ◽  
Protease Activity ◽  
Proteolytic Enzymes ◽  
Specific Protein ◽  
Neurosecretory Cells ◽  
Corpus Allatum ◽  
Minor Effect ◽  
Calliphora Erythrocephala ◽  
Sugar Water ◽  
The Mean

1. The protease activity of the adult Calliphora female measured on the first 5 days after emergence was found to be highly influenced by the diet, the activity of females fed on sugar, water and meat (meat-flies) being much higher than that of females fed only on sugar and water (sugar-flies). 2. The development of the enzyme(s) was found to be controlled by the medial neurosecretory cells (m.n.c.), the mean protease activity of females deprived of their m.n.c. only amounting to one-quarter to one-third of the maximum values for the meat-flies. 3. Implantation of corpora cardiaca-allata (presumably containing m.n.c. hormone) into females without m.n.c. raised the protease activity of these significantly, showing that the influence of the implanted organs must be hormonal. 4. The corpus allatum was found to have a certain, if minor, effect on the protease activity. 5. It is concluded that in Calliphora the eating of meat exerts its effect on the production of protease mainly indirectly by causing liberation of m.n.c. hormone into the blood. 6. As proteases are themselves proteins, the effect of the m.n.c. hormone on the production of proteolytic enzymes by the gut cells must be regarded as an effect on the specific protein synthesis of these cells. There is some evidence that the m.n.c. hormone might be involved in the regulation of protein synthesis in general.

Multimerin Processing by Cells With and Without Pathways for Regulated Protein Secretion

Blood ◽  
1999 ◽  
Vol 94 (4) ◽  
pp. 1337-1347 ◽  
Author(s):  
Catherine P.M. Hayward ◽  
Zhili Song ◽  
Shilun Zheng ◽  
Roxanna Fung ◽  
Menaka Pai ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein Secretion ◽  
Proteolytic Processing ◽  
Posttranslational Processing ◽  
Factor V ◽  
Regulated Secretion ◽  
Secretion Granules ◽  
Granule Membrane ◽  
Processing And Storage ◽  
The Impact

Abstract Multimerin is a massive, soluble, homomultimeric, factor V-binding protein found in platelet -granules and in vascular endothelium. Unlike platelets, endothelial cells contain multimerin within granules that lack the secretory granule membrane protein P-selectin, and in culture, they constitutively secrete most of their synthesized multimerin. To further evaluate multimerin’s posttranslational processing and storage, we expressed human endothelial cell prepromultimerin in a variety of cell lines, with and without pathways for regulated secretion. The recombinant multimerin produced by these different cells showed variations in its glycosylation, proteolytic processing, and multimer profile, and human embryonic kidney 293 cells recapitulated multimerin’s normal processing for constitutive secretion by human endothelial cells. When multimerin was expressed in a neuroendocrine cell line capable of regulated protein secretion, it was efficiently targeted for regulated secretion. However, the multimerin stored in these cells was proteolyzed more extensively than normally occurs in platelets, suggesting that endoproteases similar to those expressed by megakaryocytes are required to produce platelet-type multimerin. The impact of the tissue-specific differences in multimerin’s posttranslational processing on its functions is not yet known. Multimerin’s sorting and targeting for regulated secretion may be important for its functions and its association with factor V in secretion granules.

Induction of Hepatocyte Differentiation by the Extracellular Matrix and an RGD-Containing Synthetic Peptide

1991 ◽  
Vol 252 ◽  
Author(s):  
David J. Mooney ◽  
Robert Langer ◽  
Linda K. Hansen ◽  
Joseph P. Vacanti ◽  
Donald E. Ingber
Keyword(s):  
Extracellular Matrix ◽  
Protein Secretion ◽  
Synthetic Peptide ◽  
Cell Spreading ◽  
Specific Protein ◽  
Hepatocyte Differentiation ◽  
Liver Specific Protein ◽  
Extensive Cell ◽  
Adhesive Interactions

ABSTRACTTo design novel biomaterials for hepatocyte transplantation it will be necessary to determine whether specific extracellular matrix (ECM) molecule(s) or the adhesive interactions between the surface and hepatocytes are responsible for regulation of hepatocyte function. Purified ECM molecules (laminin, fibronectin, types I and IV collagen) and a synthetic peptide containing the arginine-glycine-aspartate (RGD) cell-binding sequence were precoated at defined densities to non-adhesive polystyrene dishes. Hepatocytes cultured on dishes coated with a low density of ECM molecules (1 ng/cm2) maintained a round morphology, and high liver-specific protein secretion rates. In contrast, culturing hepatocytes on increasing ECM densities (50–1000 ng/cm2) resulted in extensive cell spreading, a loss of liver-specific protein secretion, and cell growth. Hepatocytes cultured on dishes coated with the RGD-containing peptide did not spread even on a high density of the peptide (10,000 ng/cm2), and albumin secretion remained high for hepatocytes cultured on all peptide densities (1–10,000 ng/cm2). These results suggest that a variety of ECM molecules and synthetic peptides are capable of inducing hepatocyte differentiation in vitro, and these effects depend on their ability to promote cell spreading.

scholarly journals The metabolism of the insecticide carbaryl (1-naphthyl N-methylcarbamate) by fat body of the blowfly larva Calliphora erythrocephala

1969 ◽  
Vol 112 (2) ◽  
pp. 133-138 ◽  
Author(s):  
G. M. Price ◽  
R. J. Kuhr
Keyword(s):  
Incubation Medium ◽  
Magnesium Chloride ◽  
Fat Body ◽  
Subcellular Fractionation ◽  
Calliphora Erythrocephala ◽  
Carbaryl Metabolism

1. Carbaryl is metabolized more rapidly by fat body of the blowfly larva than by gut, muscle, cuticle or haemolymph. 2. Metabolism of carbaryl by the fat body is affected by the age of the larva, the pH of the incubation medium, and the concentration of magnesium chloride in the incubation medium. 3. Chloramphenicol, 2,4-dinitrophenol and 5-dimethylamino-6-nitro-1,3-benzodioxole (a carbaryl synergist) inhibit carbaryl metabolism by the fat body. 4. Subcellular fractionation of the fat body indicates that the pellet sedimenting at 30000g is the most reactive with carbaryl. 5. Probable metabolites of carbaryl formed by the fat body include the 4- and 5-hydroxy derivatives, and, possibly, the N-hydroxymethyl and 5,6-dihydrodihydroxy derivatives.

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