scholarly journals Biosynthesis and secretion of dermatan sulphate proteoglycans in cultures of human skin fibroblasts

1984 ◽  
Vol 220 (2) ◽  
pp. 575-582 ◽  
Author(s):  
L Cöster ◽  
I Carlstedt ◽  
A Malmström ◽  
B Särnstrand

Fibroblasts in culture were incubated with [3H]leucine and [35S]sulphate for 1-24 h. A large glucuronic acid-rich and a small iduronic acid-rich dermatan sulphate proteoglycan were isolated with the use of isopycnic density-gradient centrifugation, ion-exchange and gel chromatography. After 3 h the accumulation in the cell layer of the small proteoglycan reached a steady state, whereas the large one continued to increase, albeit more slowly. In the medium both proteoglycans accumulated ‘linearly’, although the large one appeared somewhat later than the small one. The composition of the polysaccharide chains and the size of the protein cores did not vary during the experiment. The two proteoglycans were synthesized at approximately similar rates, but were distributed differently in the culture. The small proteoglycan was mainly confined to the medium, whereas the large one was found in the medium as well as in a cell-associated pool. There was an intracellular accumulation of iduronic acid-rich dermatan sulphate as free polysaccharides.

1992 ◽  
Vol 70 (6) ◽  
pp. 470-474 ◽  
Author(s):  
P. Sindelar ◽  
C. Valtersson

Incubation of small unilamellar vesicles consisting of dioleoyl phosphatidylcholine – dioleoyl phosphatidylethanolamine (3:1) and 2 mol% [3H]dolichol-19 with postheparin plasma from rat resulted in the formation of dolichyl oleate. Normal plasma or heat-treated postheparin plasma contained no activity and, hence, the results indicate the presence of a cell surface associated dolichol acyltransferase that can be released into the blood by heparin. The reaction is strongly stimulated by phosphatidylethanolamine and Ca2+, whereas no stimulation with triglycerides or acyl-CoA was observed. Together with the fact that the only product formed was dolichyl oleate, these results strongly suggest that a transacylation mechanism from the phospholipids to dolichol is operative in the liposomes. Gel chromatography of postheparin plasma yielded a molecular mass of about 350 kilodaltons for the active enzyme and density gradient centrifugation indicated that this high molecular mass complex consists mainly of proteins. Finally, we conclude that this enzyme is not unique to the rat, but is also present in human postheparin plasma.Key words: phospholipids, dolichol, plasma, heparin, acyltransferase(s).


1979 ◽  
Vol 183 (3) ◽  
pp. 669-681 ◽  
Author(s):  
L Cöster ◽  
I Carlstedt ◽  
A Malmström

35SO42– and [3H]-leucine-labelled proteoglycans were isolated from the medium of a fibroblast culture, from an EDTA extract of the monolayer, and from consecutive dithiothreitol and guanidine hydrochloride extracts of the cells. Proteoglycans of different sizes were isolated from the extracts by gel chromatography on Sepharose 4B. In the medium and the EDTA extract the largest proteoglycans contained only 35S-labelled galactosaminoglycan, whereas all other fractions contained in addition heparan [35S-labelled galactosaminoglycan, whereas all other fractions contained in addition heparin [35S]sulphate. The galactosaminoglycan-containing proteoglycans of the various extracts were separated into a larger component, containing chondroitin sulphate-like side chains, and a smaller component, containing dermatan sulphate. The larger proteoglycan of the medium showed reversible association-dissociation behaviour when chromatographed on Sepharose CL2B in phosphate-buffered saline and 4M-guanidine hydrochloride respectively. This property remained after removal of extraneous proteins by CsCl-density-gradient centrifugation in guanidine hydrochloride. The association was markedly increased by the addition of high-molecular-weight hyaluronic acid.


1991 ◽  
Vol 276 (2) ◽  
pp. 533-539 ◽  
Author(s):  
L Cöster ◽  
J Hernnäs ◽  
A Malmström

Incubation of cultured fibroblasts with p-nitrophenyl beta-D-xyloside resulted in a concentration-dependent increase in galactosaminoglycan synthesis. At low concentration of added xyloside large and small radiolabelled proteoglycans and xyloside-bound polysaccharides were recovered from the medium, whereas at high concentrations only xyloside-bound polysaccharides were found. In the cell layer proteoglycans and xyloside-bound polysaccharides were found at all concentrations tested. Only galactosaminoglycan chains were polymerized on the xyloside primer. At low concentrations of added xyloside the structure of the galactosaminoglycans formed on the xyloside was similar to that of the small dermatan sulphate proteoglycan, i.e. mainly composed of L-iduronic acid-containing 4-sulphated disaccharides. With increasing concentration of added xyloside the co-polymeric structure of the small dermatan sulphate proteoglycan and the xyloside-bound polysaccharide was changed to contain a larger proportion of D-glucuronosyl residues with only slight changes in the sulphation pattern. No structural change in the polysaccharide chains of the large glucuronic acid-rich proteoglycans occurred. At 1 mM-xyloside, where no proteoglycans were formed, the polysaccharide was shorter and composed mainly of D-glucuronosyl-containing disaccharides with a ratio of 4-sulphate to 6-sulphate substituents of 1:2. This is similar to the structure of the large glucuronic acid-rich proteoglycan synthesized by these cells. Thus the main difference induced by the xyloside treatment was changed polymer modification at high xyloside concentrations. The specific activities of the polymer-modifying enzymes, uronosyl C-5-epimerase and 4-sulphotransferase, were therefore measured and found to be decreased by 30-50% in fibroblasts treated with high xyloside concentrations. It is suggested that the protein core is of importance for regulating the activity of the polymer-modifying enzymes.


1981 ◽  
Vol 193 (1) ◽  
pp. 143-153 ◽  
Author(s):  
L Cöster ◽  
L A Fransson

1. Proteoglycans were extracted from sclera with 4 M-guanidine hydrochloride in the presence of proteinase inhibitors and purified by ion-exchange chromatography and density-gradient centrifugation. 2. The entire proteoglycan pool was characterized by compositional analyses and by specific chemical (periodate oxidation) and enzymic (chondroitinases) degradations. The glycan moieties of the molecules were exclusively galactosaminoglycans (dermatan sulphate-chondroitin sulphate co-polymers). In addition, the preparations contained small amounts of oligosaccharides. 3. The scleral proteodermatan sulphates were fractionated into one larger (I) and one smaller (II) component by gel chromatography. Proteoglycan I was eluted in a more excluded position on gel chromatography in 0.5 M-sodium acetate than in 4.0 M-guanidine hydrochloride. Reduced and alkylated proteoglycan I was eluted in the same position (in 0.5 M-sodium acetate) as was the starting material (in 4.0 M-guanidine hydrochloride). The elution position of proteoglycan II was the same in both solvents. Proteoglycans I and II had s0 20,w values of 2.8 × 10(-13) and 2.2 × 10(-13) s respectively in 6.0 M-guanidine hydrochloride. 4. The two proteoglycans differed with respect to the nature of the protein core and the co-polymeric structure of their side chains. Also proteoglycan I contained more side chains than did proteoglycan II. The dermatan sulphate side chains of proteoglycan I were D-glucuronic acid-rich (80%), whereas those of proteoglycan II contained equal amounts of D-glucuronic acid and L-iduronic acid. Furthermore, the co-polymeric features of the side chains of proteoglycans I and II were different. The protein core of proteoglycan I was of larger size than that of proteoglycan II. The latter had an apparent molecular weight of 46 000 (estimated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis), whereas the former was greater than 100 000. In addition, the amino-acid composition of the two core preparations was different. 5. As proteoglycan I altered its elution position on gel chromatography in 4 M-guanidine hydrochloride compared with 0.5 M-sodium acetate it is proposed that a change in conformation or a disaggregation took place. If the latter hypothesis is favoured, aggregation may be due to self-association or mediated by an extrinsic molecule, e.g. hyaluronic acid.


1972 ◽  
Vol 126 (4) ◽  
pp. 791-803 ◽  
Author(s):  
T. E. Hardingham ◽  
Helen Muir

The kinetics of incorporation of [35S]sulphate into slices of pig laryngeal cartilage in vitro was linear with time up to 6h. The specific radioactivities of the extracted proteoglycans (containing about 80% of the uronic acid of the cartilage) and the glycosaminoglycans remaining in the tissue after extraction were measured after various times of continuous and ‘pulse–chase’ radioactivity incorporation. Radioactivity was present in the isolated chondroitin sulphate after 2 min, but there was a 35min delay in its appearance in the extractable proteoglycan fraction. Fractionation of the proteoglycans by gel chromatography showed that the smallest molecules had the highest specific radioactivity, but ‘pulse–chase’ experiments over 5h did not demonstrate any precursor–product relationships between fractions of different size. Equilibrium density-gradient centrifugation in 4m-guanidine hydrochloride showed that among the proteoglycan fractions the specific radioactivity increased as the chondroitin sulphate content decreased, but with preparations from ‘pulse–chase’ experiments there was again no evidence for precursor–product relationships between the different fractions. Differences in radioactive incorporation would seem to reflect metabolic heterogeneity within the proteoglycans extracted from cartilage. This may be due either to a partial separation of different types of proteoglycans or to differences in the rates of degradation of the molecules of different size and composition as a result of the nature and specificity of the normal degrading enzymes. The results suggest that molecules of all sizes were formed at the same time.


Author(s):  
Christina Wichmann ◽  
Petra Rösch ◽  
Jürgen Popp

AbstractRaman spectroscopy is an analytical method to identify medical samples of bacteria. Because Raman spectroscopy detects the biochemical properties of a cell, there are many factors that can influence and modify the Raman spectra of bacteria. One possible influence is a proper method for isolation of the bacteria. Medical samples in particular never occur in purified form, so a Raman-compatible isolation method is needed which does not affect the bacteria and thus the resulting spectra. In this study, we present a Raman-compatible method for isolation of bacteria from bronchoalveolar lavage (BAL) fluid using density gradient centrifugation. In addition to measuring the bacteria from a patient sample, the yield and the spectral influence of the isolation on the bacteria were investigated. Bacteria isolated from BAL fluid show additional peaks in comparison to pure culture bacteria, which can be attributed to components in the BAL sample. The isolation gradient itself has no effect on the spectra, and with a yield of 63% and 78%, the method is suitable for isolation of low concentrations of bacteria from a complex matrix.


1991 ◽  
Vol 276 (3) ◽  
pp. 667-675 ◽  
Author(s):  
D J Thornton ◽  
J K Sheehan ◽  
H Lindgren ◽  
I Carlstedt

Mucus glycoproteins (mucins) were isolated from sputum of patients with cystic fibrosis (CF) after separation into sol and gel phases. The mucus gel was solubilized with gentle stirring in 6 M-guanidinium chloride supplemented with proteinase inhibitors, and purification of mucins was subsequently achieved by isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. Density-gradient centrifugation also revealed a heterogeneity of the macromolecules, the pattern of which varied between individuals, and mucins from the gel phase was pooled as ‘heavy’ and ‘light’ fractions. Gel chromatography on Sepharose CL-2B showed that the heavy fraction contained a larger proportion of smaller species than the ‘light’ fraction and that the gel phase mucins were much larger than those from the sol. An apparently homogeneous high-Mr mucin population from one individual contained approx. 70% (w/w) carbohydrate, the major sugars being N-acetylglucosamine (17.8%), N-acetylgalactosamine (6.7%), galactose (20.7%), fucose (13.2%) and sialic acid (11.4%). These mucins had an S020.w of 47 S, and an Mr of 15 x 10(6) -20 x 10(6), and rate-zonal centrifugation revealed a polydisperse size distribution [range (5-30) x 10(6)] with a weight-average Mr of 17 x 10(6). The whole mucins were visualized with electron microscopy as linear and apparently flexible threads, disperse in size. Reduction produced subunits which were included on Sepharose CL-2B, and subsequent trypsin digestion yielded high-Mr glycopeptides which were further retarded. The size distributions and fragmentation patterns of mucin from two other CF patients were the same, as studied by gel chromatography, rate-zonal centrifugation and electron microscopy. We conclude that CF mucins are heterogeneous in both size and buoyant density and that the various populations, though differing in buoyant density, share the same architecture and macromolecular properties and are, in this respect, similar to mucins from normal respiratory secretions [Thornton, Davies, Kraayenbrink, Richardson, Sheehan & Carlstedt (1990) Biochem. J. 265, 179-186] and human cervical mucus [Carlstedt & Sheehan (1989) SEB Symp. XLIII 289-316].


1979 ◽  
Author(s):  
B. Casu

The structure of heparin is largely accounted for by disaccharide sequences of α1,4-linked 2-0-sulphated L-iduroic acid and N,6-0-disulphated D-glucosamine. However, the insertion of other residues (especially D-glucuronic acid, nor-sulphated L-iduronic acid and N-acetylated D-glucosamine) leads to hybrid structures. Also the other iduromc acid-containing glycosaminoglycans are structurally heterogeneous. Heparan sulphates contain variable amounts of heparin-like blocks, ana dermatan sulphate contains also chondroitin -like segments.Available evidence on the structure and conformation of the above glycosaminoglycans will be discussed in terms of the availability ot individual functional groups for interaction with plasma proteins.


Blood ◽  
1973 ◽  
Vol 42 (2) ◽  
pp. 195-208 ◽  
Author(s):  
K. A. Dicke ◽  
M. J. van Noord ◽  
B. Maat ◽  
U. W. Schaefer ◽  
D. W. van Bekkum

Abstract The colony-forming unit culture (CFU-C) in the thin-layer agar colony technique is considered to be representative for hemopoietic stem cells (HSC), according to our studies in mouse and monkey bone marrow. Using this in vitro assay as a guide, stem cell concentrates were prepared from monkey and human bone marrow by repeated density gradient centrifugation. The number of CFU-C could be enriched up to 70-100-fold. In such concentrated CFU-C suspensions, a cell, morphologically identical with the hemopoietic stem cell in the mouse (MSCLC, mouse stem cell-like cell) was frequently observed, using a May-Grünwald-Giemsa (MGG) staining method and electron microscope techniques. In MGG-stained preparations, the MSCLC superficially resembles the small lymphocyte; therefore, a staining method has been described, the polychrome procedure, by which both cell populations could be clearly distinguished. Since a fair correlation exists between the number of MSCLC and the number of CFU-C in a variety of primate hemopoietic suspensions, we concluded that the MSCLC might be a good candidate for being the HSC in monkeys and man.


1990 ◽  
Vol 265 (1) ◽  
pp. 179-186 ◽  
Author(s):  
D J Thornton ◽  
J R Davies ◽  
M Kraayenbrink ◽  
P S Richardson ◽  
J K Sheehan ◽  
...  

Mucous secretions were collected from tracheas of patients undergoing minor surgery under general anaesthesia with tracheal intubation, and mucus glycoproteins were isolated by using isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. ‘Whole’ mucins were excluded from a Sepharose CL-2B gel, whereas subunits obtained after reduction were included. Trypsin digestion of subunits afforded high-Mr glycopeptides (T-domains), which were further included in the gel. The latter fragments are heterogeneous and comprise two or three populations, as indicated by gel chromatography and ion-exchange h.p.l.c. Rate-zonal centrifugation showed that the ‘whole’ mucins are polydisperse in size, with a weight-average Mr of (14-16) x 10(6). The macromolecules were observed by electron microscopy, as linear and apparently flexible thread-like structures. Subunits and T-domains had weight-average contour lengths of 490 nm and 160 nm respectively. It is concluded that mucus glycoproteins are present in secretions from the healthy lower respiratory tract. The ‘whole’ tracheal mucins are assembled from subunits, which in turn can be fragmented into high-Mr glycopeptides corresponding to the oligosaccharide domains typically found in mucus glycoproteins. The size and macromolecular architecture of the tracheal mucins is thus similar to that observed for mucins from human cervical mucus, chronic bronchitic sputum and pig stomach, providing yet another example of this general design of these macromolecules, i.e. subunits assembled end-to-end into very large linear and flexible macromolecules.


Sign in / Sign up

Export Citation Format

Share Document