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J Welin

Publications and source records attributed to J Welin.

At least 19 recordsLinked to original sources
PubMed2004

Protein expression by Streptococcus mutans during initial stage of biofilm formation.

Cells growing on surfaces in biofilms exhibit properties distinct from those of planktonic cells, such as increased resistance to biocides and antimicrobial agents. In spite of increased interest in biofilms, very little is known about alterations in cell physiology that occur upon attachment of cells to a surface. In this study we have investigated the changes induced in the protein synthesis by contact of Streptococcus mutans with a surface. Log-phase planktonic cells of S. mutans were allowed to adhere to a glass slide for 2 h in the presence of a (14)C-amino acid mixture. Nonadhered cells were washed away, and the adhered cells were removed by sonication. The proteins were extracted from the nonadhered planktonic and the adhered biofilm cells and separated by two-dimensional gel electrophoresis followed by autoradiography and image analysis. Image analysis revealed that the relative rate of synthesis of 25 proteins was enhanced and that of 8 proteins was diminished > or =1.3-fold in the biofilm cells. Proteins of interest were identified by mass spectrometry and computer-assisted protein sequence analysis. Of the 33 proteins associated with the adhesion response, all but 10 were identified by mass spectrometry and peptide mass fingerprinting. The most prominent change in adhered cells was the increase in relative synthesis of enzymes involved in carbohydrate catabolism indicating that a redirection in protein synthesis towards energy generation is an early response to contact with and adhesion to a surface.

Bacterial Adhesion↗
PubMed2003

Effect of acid shock on protein expression by biofilm cells of Streptococcus mutans.

Streptococcus mutans is a component of the dental plaque biofilm and a major causal agent of dental caries. Log-phase cells of the organism are known to induce an acid tolerance response (ATR) at sub-lethal pH values ( approximately 5.5) that enhances survival at lower pH values such as those encountered in caries lesions. In this study, we have employed a rod biofilm chemostat system to demonstrate that, while planktonic cells induced a strong ATR at pH 5.5, biofilm cells were inherently more acid resistant than such cells in spite of a negligible induction of an ATR. Since these results suggested that surface growth itself triggered an ATR in biofilm cells, we were interested in comparing the effects of a pH change from 7.5 to 5.5 on protein synthesis by the two cell types. For this, cells were pulse labeled with [(14)C]-amino acids following the pH change to pH 5.5, the proteins extracted and separated by two-dimensional (2D) electrophoresis followed by autoradiography and computer-assisted image analysis. A comparison between the cells incubated at pH 5.5 and the control biofilm cells revealed 23 novel proteins that were absent in the control cells, and 126 proteins with an altered relative rate of synthesis. While the number of changes in protein expression in the biofilm cells was within the same range as for planktonic cells, the magnitude of their change was significantly less in biofilm cells, supporting the observation that acidification of biofilm cells induced a negligible ATR. Mass spectrometry and computer-assisted protein sequence analysis revealed that ATR induction of the planktonic cells resulted in the downregulation of glycolytic enzymes presumably to limit cellular damage by the acidification of the external environment. On the other hand, the glycolytic enzymes in control biofilm cells were significantly less downregulated and key enzymes, such as lactate dehydrogenase were upregulated during pH 5.5 incubation, suggesting that the enhanced acid resistance of biofilm cells is associated with the maintenance of pH homeostasis by H+ extrusion via membrane ATPase and increased lactate efflux.

Acids↗
PubMed2001

Protein expression by planktonic and biofilm cells of Streptococcus mutans.

Streptococcus mutans, a major causal agent of dental caries, functions in nature as a component of a biofilm on teeth (dental plaque) and yet very little information is available on the physiology of the organism in such surface-associated communities. As a consequence, we undertook to examine the synthesis of proteins by planktonic and biofilm cells growing in a biofilm chemostat at pH 7.5 at a dilution rate of 0.1 h(-1) (mean generation time=7 h). Cells were incubated with (14)C-labelled amino acids, the proteins extracted and separated by two-dimensional electrophoresis followed by autoradiography and computer-assisted image analysis. Of 694 proteins analysed, 57 proteins were enhanced 1.3-fold or greater in biofilm cells compared to planktonic cells with 13 only expressed in sessile cells. Diminished protein expression was observed with 78 proteins, nine of which were not expressed in biofilm cells. The identification of enhanced and diminished proteins by mass spectrometry and computer-assisted protein sequence analysis revealed that, in general, glycolytic enzymes involved in acid formation were repressed in biofilm cells, while biosynthetic processes were enhanced. The results show that biofilm cells possess novel proteins, of as yet unknown function, that are not present in planktonic cells.

Animals↗
PubMed1982

[Angiomatous cutaneous lesions revealing arteriovenous fistulas (author's transl)].

Reports of Bluefarb-Stewart syndrome have been infrequent. Two observations of this condition are described. Both patients are young men who presented with extensive angiomatous lesions of the feet, revealing distal arteriovenous fistulas. Surgical treatment was successful in one patient. Diagnostic criteria are discussed. As to pathogenesis the most likely hypothesis is that the arteriovenous fistulas are congenital. Bluefarb-Stewart syndrome can therefore be classified as one of the angiodysplasias.

Adult↗
PubMed1977

[Teutschlaender lipo-calcino-granulomatosis or tumoral calcinosis of Inclan (author's transl)].

The present report describes a typical case of tumoral calcinosis. Differential diagnosis was initially directed towards sarcoma suggested by fibrous connective tissue surrounding cystlike cavities. The course of this disease led to chronic multiple fistulae with secondary infection in spite of two attempts of surgical excision. This case adds further support to the results of earlier reports showing no specific biological abnormalities. The present sutyd indicates otherwise that tumoral calcinosis and lipo-calcino-granulomatosis of Teutschlaender are the same condition. The pathogenesis of this affection remains enigmatic; there is no evidence that the lipidic excess should be the beginning of the process, but this disease must be considered as a distinctive form of calcinosis. The surgical exeresis is the only possible treatment, even if it doesn't prevent recurrence.

Adult↗
PubMed1975

[Acquired ulcero-mutilating acropathies in adults. Critical study of 150 personal cases].

The authors review critically a series of cases, followed up by the authors, of acrodynia and trophic ulcers occurring either in alcoholics (119 cases) or in diabetics (28 cases), who were also often alcoholic as well. The symptoms were similar in both groups. However, the poor nutrition was generally more market in the alcoholics. The trophic disorders were very similar, together with the sensory disorders. However, the deep sensitivity was less rarely involved in diabetics. Above all, the study of the rate of conduction of the motor nerve fibers showed axonal involvement in alcoholics and segmental demyelinisation in diabetics. The treatment was mainly dietary, together with proper hygiene and immobilisation of the foot.

Adult↗