Different routes for integral protein insertion into Ricinus communis protein-body and glyoxysome membranes

Planta ◽  
1989 ◽  
Vol 179 (3) ◽  
pp. 331-339 ◽  
Author(s):  
Claire Halpin ◽  
Michael J. Conder ◽  
J. Michael Lord
Planta ◽  
1984 ◽  
Vol 160 (4) ◽  
pp. 330-340 ◽  
Author(s):  
Michael M�der ◽  
Maarten J. Chrispeels

1985 ◽  
Vol 63 (12) ◽  
pp. 2121-2128 ◽  
Author(s):  
John S. Greenwood ◽  
J. Derek Bewley

The development of the endosperm of castor bean seed from its initial free nuclear state through to the end of maturation is presented. An investigation of the pattern of reserve accumulation in the endosperm at the light microscopy level revealed that the accumulation of soluble and insoluble storage proteins, and of phytin, does not occur simultaneously in all cells of the developing storage organ. Rates of reserve accumulation also vary among regions of the endosperm. Storage protein and phytin accumulation are initiated in a region midway between the periphery and central lumen of the endosperm by the early cotyledon stage of seed development. Afterwards, reserve deposition occurs more intensely in the proximal and more peripheral regions than in the distal and internal regions. A wave of reserve accumulation, or protein body maturation, proceeds from the more peripheral and the proximal regions to the more internal and distal regions as development continues. The last cells to complete reserve deposition are those in regions lying close to the endosperm lumen (into which the cotyledons have expanded) and the outermost two cell layers of the endosperm.


1990 ◽  
Vol 68 (11) ◽  
pp. 2353-2360 ◽  
Author(s):  
M. J. Brown ◽  
J. S. Greenwood

The developing endosperm of castor bean has been used extensively as a model system for studies of storage-protein synthesis and processing, yet the path of transport of the storage proteins to the protein bodies has not been elucidated. In this study, immunolocalization of the 11S globulin (crystalloid protein) was performed on sections of acrolein–glutaraldehydefixed, resin-embedded, developing castor bean endosperm. Acrolein allowed rapid fixation of the tissue necessary for preserving the ultrastructure of the endomembrane system while maintaining adequate antigenicity of the target protein. Crystalloid protein was localized in the rough endoplasmic reticulum, the known site of synthesis, and in the dense proteinaceous inclusions within the protein bodies. In addition, significant labelling of Golgi complexes and associated vesicles, 65-nm diameter coated vesicles, and larger 220-nm diameter cytoplasmic vesicles was obtained. The findings provide the first direct evidence that the storage parenchyma cells of developing castor bean endosperm possess well-developed, functional Golgi complexes. This is consistent with previous observations of seed storage proteins in other plant species. The study further suggests that two distinct classes of vesicles are involved in the transport of the 11S globulin to the protein bodies. Key words: Golgi, immunolocalization, protein body, Ricinus communis, storage protein, transport (protein).


Author(s):  
D.C. Hixson ◽  
J.C. Chan ◽  
J.M. Bowen ◽  
E.F. Walborg

Several years ago Karasaki (1) reported the production of type C virus particles by Novikoff ascites hepatocarcinoma cells. More recently, Weinstein (2) has reported the presence of type C virus particles in cell cultures derived from transplantable and primary hepatocellular carcinomas. To date, the biological function of these virus and their significance in chemically induced hepatocarcinogenesis are unknown. The present studies were initiated to determine a possible role for type C virus particles in chemically induced hepatocarcinogenesis. This communication describes results of studies on the biological and surface properties of type C virus associated with Novikoff hepatocarcinoma cells.Ecotropic and xenotropic murine leukemia virus (MuLV) activity in ascitic fluid of Novikoff tumor-bearing rats was assayed in murine sarcoma virus transformed S+L- mouse cells and S+L- mink cells, respectively. The presence of sarcoma virus activity was assayed in non-virus-producing normal rat kidney (NRK) cells. Ferritin conjugates of concanavalin A (Fer-Con wheat germ agglutinin (Fer-WGA), and Ricinus communis agglutinins I and II (Fer-RCAI and Fer-RCAII) were used to probe the structure and topography of saccharide determinants present on the viral envelope.


Author(s):  
Robert E. Nordquist ◽  
J. Hill Anglin ◽  
Michael P. Lerner

A human breast carcinoma cell line (BOT-2) was derived from an infiltrating duct carcinoma (1). These cells were shown to have antigens that selectively bound antibodies from breast cancer patient sera (2). Furthermore, these tumor specific antigens could be removed from the living cells by low frequency sonication and have been partially characterized (3). These proteins have been shown to be around 100,000 MW and contain approximately 6% hexose and hexosamines. However, only the hexosamines appear to be available for lectin binding. This study was designed to use Concanavalin A (Con A) and Ricinus Communis (Ricin) agglutinin for the topagraphical localization of D-mannopyranosyl or glucopyranosyl and D-galactopyranosyl or DN- acetyl glactopyranosyl configurations on BOT-2 cell surfaces.


1988 ◽  
Vol 60 (02) ◽  
pp. 182-187 ◽  
Author(s):  
Morio Aihara ◽  
Ken Tamura ◽  
Ryuko Kawarada ◽  
Keizou Okawa ◽  
Yutaka Yoshida

SummaryThe adhesion of human fixed washed platelets (FWP) to collagen was decreased after treatment with Serratia marcescens protease (SP), which removed 95% of the glycocalicin from platelet membrane glycoprotein (GP) lb. However, the diminished adhesion of SP treated FWP to collagen could still be increased in the presence of purified von Willebrand factor (vWF). This ability of vWF to increase FWP adhesion to collagen is defined as collagen cofactor (CCo). The adhesion of FWP to collagen was not affected by a monoclonal antibody (MAb) to GP Ilb/IIIa (10E5), that inhibits ADP and collagen induced platelet aggregation. On the other hand, it was decreased by 50% by a MAb to GP lb (6D1), that inhibits ristocetin induced platelet aggregation. Adhesion of FWP in buffer to collagen was completely inhibited by Ricinus communis agglutinin I or concanavalin A, while Lens culinalis agglutinin and wheat germ agglutinin showed 50% inhibition. The FWP adhesion to collagen in the presence of vWF (normal plasma) was unaffected by MAbs to GP Ilb/IIIa (10E5, P2, HPL1) but was decreased to 32-38% by MAbs to GP lb (6D1, AN51, HPL11). A MAb to vWF (CLB-RAg 35), that inhibits ristocetin induced binding of vWF to platelets, decreased the CCo of normal plasma by 70%. The MAb, CLB-RAg 201, that inhibits the binding of vWF to collagen, completely inhibited the CCo of normal plasma. In conclusion, our data suggest that (1) GP lb has a partial role in FWP adhesion to collagen; (2) the binding of vWF to collagen is required for the expression of CCo; (3) CCo is partly mediated through GP lb; but (4) other platelet membrane protein(s) besides GP lb or GP Ilb/IIIa must also be involved in FWP-vWF-collagen interactions.


1986 ◽  
Vol 55 (03) ◽  
pp. 338-341 ◽  
Author(s):  
H Takahashi ◽  
W Tatewaki ◽  
M Hanano ◽  
R Nagayama ◽  
A Shibata

SummaryPlatelet-type von Willebrand’s disease (vWD) is a bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet abnormality (probably in GPIb). Platelet aggregability was nearly normal in response to thrombin, wheat germ agglutinin and Ricinus communis agglutinin in this disorder. Unmodified platelets showed no aggregation upon the addition of peanut agglutinin. Partially purified human vWF induced little aggregation of washed patient platelets, but the aggregation was greatly enhanced in the presence of plasma devoid of vWF. Monoclonal antibodies directed against GPIb and GPIIb/IIIa as well as EDTA completely inhibited vWF-induced aggregation. These results indicate that human vWF induces aggregation of platelet-type vWD platelets in the presence of divalent cations and some plasma cofactor(s), and that both GPIb and GPIIb/IIIa are involved in this aggregation.


Reproduction ◽  
2000 ◽  
pp. 325-335 ◽  
Author(s):  
A Calvo ◽  
LM Pastor ◽  
S Bonet ◽  
E Pinart ◽  
M Ventura

Lectin histochemistry was used to perform in situ characterization of the glycoconjugates present in boar testis and epididymis. Thirteen horseradish peroxidase- or digoxigenin-labelled lectins were used in samples obtained from healthy fertile boars. The acrosomes of the spermatids were stained intensely by lectins with affinity for galactose and N-acetyl-galactosamine residues, these being soybean, peanut and Ricinus communis agglutinins. Sertoli cells were stained selectively by Maackia ammurensis agglutinin. The lamina propria of seminiferous tubules showed the most intense staining with fucose-binding lectins. The Golgi area and the apical part of the principal cells of the epididymis were stained intensely with many lectins and their distribution was similar in the three zones of the epididymis. On the basis of lectin affinity, both testis and epididymis appear to have N- and O-linked glycoconjugates. Spermatozoa from different epididymal regions showed different expression of terminal galactose and N-acetyl-galactosamine. Sialic acid (specifically alpha2,3 neuraminic-5 acid) was probably incorporated into spermatozoa along the extratesticular ducts. These findings indicate that the development and maturation of boar spermatozoa are accompanied by changes in glycoconjugates. As some lectins stain cellular or extracellular compartments specifically, these lectins could be useful markers in histopathological evaluation of diseases of boar testis and epididymis.


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