0000000000007832
AUTHOR
G. Uhlenbruck
Possible control mechanism of cell motility in the gorgonian Eunicella cavolinii
In a previous study it was demonstrated that a lectin controls cell-cell interaction in the gorgonian Eunicella cavolinii (Koch) as a negative modulator. Now we describe the procedure to purify this lectin to homogeneity; its molecular weight is 23 400. The homologous proteoglycans were identified as positive modulators of cell-cell (and/or cell substrate) interaction. The purified single proteoglycan aggregates were 1200±700 nm long and the distance between the attachment points of the proteoglycan subunits was about 45 nm. The glycosaminoglycan residues of the gorgonian proteoglycans were identified as hyaluronic acid (35.5%), heparan sulfate (47.9%) and dermatan sulfate (14.1%). Binding …
Demonstration of an endocrine signaling circuit for insulin in the sponge Geodia cydonium.
Abstract The existence of an insulin-mediated cell-to-cell signaling in the sponge Geodia cydonium is demonstrated in this study by molecular biological and immunological techniques. The sequence of a sponge cDNA clone encoding preproinsulin was analyzed for the first time and determined to comprise a high homology to human preproinsulin (60-80% homology). The predicted polypeptide of preproinsulin from sponge contains two disulfide bridges which link the A- to the B-chain. The intra-A chain disulfide bridge is absent. Applying immunological and electron microscopical techniques it is shown that insulin is produced in specialized cells (spherulous cells). Experimental evidence is presented …
Cell-cell recognition system in gorgonians: description of the basic mechanism
The dissociation of the gorgonian Eunicella cavolinii (Koch) into single cells was successfully accomplished. These cells readily formed aggregates of a size of 2 100 μm during incubation in roller tubes; no aggregate formation was observed in non-rotating Petri dishes. The formation of aggregates was not influenced by Ca++, urea or trypsin; it was also independent of temperature (4° to 30°C) and pH (5.5–9.0). The intercellular material of the gorgonian contains a galactose-specific lectin, as determined by double diffusion experiments and haemagglutination inhibition experiments using a series of galactoglycoconjugates. This lectin converted the aggregation-susceptible cells to aggregation…