Distribution of sulfated mucopolysaccharides in invertebrates.

The sulfated mucopolysaccharide composition of 22 species of invertebrates belonging to the phyla Arthropoda, Mollusca, Annelida, Tunicata, Echinodermata, Coelenterata, and Porifera was analyzed. It is shown that all the species contain variable amounts of one or more types of sulfated mocopolysaccharides, most of which similar to the ones found in vertebrates. It is shown also that each species has a characteristic composition, differing from each other regarding the relative amount and type of chondroitin sulfates A, B, and C, heparitin sulfate, and heparin. The possible biological role of the sulfated mucopolysaccharides in cell recognition or aggregation or both is discussed in view of the present findings.     

Tissue specific distribution of sulfated mucopolysaccharides in mammals.

A comparative study on the distribution of sulfated mucopolysaccharides in several tissues of five mammalian species is reported. It is shown that each tissue has a characteristic composition differing from each other regarding the relative amount, type and molecular size of chondroitin sulfate A/C, chondroitin sulfate B and heparan sulfate. It is also shown that the same tissue from different mammals has the same types and proportions of sulfated mucopolysaccharides, but with different molecular weights. Exception to this rule was observed for the distribution of heparin which was present only in a few tissues of the five mammals studied. The possible involvement of the sulfated mucopolysaccharides in cell recognition and/or adhesiveness is discussed in view of this characteristic distribution.     

Colchicine resistance in mammalian cell lines.

Colchicine-resistant variants derived from mouse and Syrian hamster lines are described. The resistant cells do not appear to be true mutants, since they appear at a high frequency, unaffected by treatment with ethyl methyl sulphonate, and are unstable in the absence of the drug. They are cross-resistant to other drugs, show a reduced rate of binding of colchicine in monolayer, and give extracts with colchicine-binding properties identical to those of the wild type. Thus the resistance is due to a permeability barrier. The naturally occurring resistance of the Syrian hamster line is specific for colchicine, and may be due to a specific permeability barrier. The Syrian hamster line is also shown to have an extra colchicine-binding pool.     

Introduction of estrogen-responsiveness into mammalian cell lines.

We introduced estrogen responsiveness as a new characteristic into rat hepatoma, mouse Ltk- and human HeLatk-cells by transfecting the human estrogen receptor (ER) cDNA. To measure the estrogen response we used Xenopus vitellogenin gene A2 constructs linked to the bacterial CAT gene. Transient cotransfections of the ER cDNA and the vitellogenin gene-CAT constructs containing the estrogen responsive element (ERE) lead to a hormone dependent induction of CAT activity whereas cotransfected vitellogenin gene constructs lacking the ERE are not inducible. Stable transfections of ER cDNA into Ltk- cells give rise to cell clones that are estrogen responsive as shown by transfection of various vitellogenin gene-CAT constructs. These results prove that the transfected ER is biologically active and is sufficient to make a cell estrogen responsive.     

Changes of sulfated mucopolysaccharides and mucopolysaccharidases during fetal development

The changes of sulfated mucopolysaccharides and mucopolysaccharidases during bovine fetal development were analyzed. It is shown that chondroitin sulfate C increases in concentration up to the 50th day of fetal development and then decreases progressively until its complete disappearance in most adult tissues. Likewise, hyaluronidase also reaches a peak on the 50th day and decreases in activity until its disappearance in adult tissues. On the other hand, heparitin sulfate and chondroitin sulfate B as well as beta-glucuronidase and beta-N-acetylglucosaminidase remain without significant changes during the whole period. The fetal chondroitin sulfate C is tissue specific with different molecular weights depending on the tissue of origin. Some properties of fetal muscle and brain hyaluronidase are also described. The possible role of chondroitin sulfate C and hyaluronidase in the processes of differentiation and division is discussed in view of the present findings.     

Tissue specific distribution of sulfated mucopolysaccharides in mammals

A comparative study on the distribution of sulfated mucopolysaccharides in several tissues of five mammalian species is reported. It is shown that each tissue has a characteristic composition differing from each other regarding the relative amount, type and molecular size of chondroitin sulfate A/C, chondroitin sulfate B and heparan sulfate. It is also shown that the same tissue from different mammals has the same types and proportions of sulfated mucopolysaccharides, but with different molecular weights. Exception to this rule was observed for the distribution of heparin which was present only in a few tissues of the five mammals studied.The possible involvement of the sulfated mucopolysaccharides in cell recognition and/or adhesiveness is discussed in view of this characteristic distribution.     

Sialic acid of mammalian cell lines

Approximately two-thirds of the total sialic acid (S.A.) per cell of a number of cell lines (L-929, L5178Y, HeLa, C13, P183, and CHO) was located at the cell surface but was inaccessible to the action of trypsin, pronase, lysozyme, β-glucuronidase, or hyaluronidase. The mean surface density of S.A. ranged from 5.4 × 10⁵ molecules/μ² surface area for the L5178Y cell to 16.1 × 10⁵ molecules/μ² for the P183 cell. The P183 cell line, which is a polyoma virus-transformed derivative of Stoker's C13 line, consistently contained more S.A. per cell than the latter under a variety of growth conditions, although the two lines did not differ in mean cell volume. When mean cell volume of C13, P183, or CHO cells was experimentally manipulated by thymidine or colcemide blockade, S.A. content per cell followed size changes closely. No evidence could be found for a shift in total S.A. per unit cell volume accompanying the period of maximum mitotic activity of partially synchronized CHO suspension cultures. Comparisons between cells grown on glass and the same cells grown in suspension, or between cells grown to different densities on glass, indicated no differences in the characteristic S.A. content per cell.     

Glycolipids and glycosyltransferases in permanent cell lines established from human medulloblastomas.

Medulloblastoma biopsies are heterogenous and might contain normal brain tissue, which limits the usefulness of such tumor material for biochemical analyses. We have, therefore, examined the gangliosides and their metabolism using the medulloblastoma cell lines. Daoy and D341 Med, cultured both in vitro and as xenografts in nude mice. The ganglioside patterns in the Daoy showed a switch from a high GM2, 70% (mol% of total ganglioside sialic acid) and low lactoseries gangliosides (2%) content in monolayer cultures, to a high proportion of lactoseries gangliosides (50%) and virtually no GM2 (1%) in xenografts, but an increased proportion of other a-series gangliosides. The D341 Med showed a similar change regarding the lacto-series gangliosides from 1% in suspension culture to 10% in xenografts. The activity of five glycosyltransferases, GM3, GD3, GM2, GM1 and LA2 synthases, did not parallel the ganglioside patterns and could not account for the noted variations therein. In the Daoy cell line the LA2 synthase as well as the GM2 synthase activity was relatively high in both culture systems, despite the marked difference in the expression of GM2 and the lactoseries gangliosides. These results suggest that environmental factors play a crucial role for the in vivo activity of the glycosyltransferases.     

Cell recognition and adhesiveness: a possible biological role for the sulfated mucopolysaccharides.

The sulfated mucopolysaccharide composition of different neonate, adult and tumoral tissues is reported. It is shown that each tissue has a characteristic composition with respect to the relative amount, type and molecular size of chondroitin sulfate $\text{A}\text{C}$, chondroitin sulfate B and heparitin sulfate. Neonate and tumor tissues contain large amounts of chondrotin sulfate $\text{A}\text{C}$ which is nearly absent in most adult and normal tissues respectively. Based on these and other results a possible role for the sulfated mucopolysaccharides in cell recognition and adhesiveness is proposed.