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Adhesion Experiments (adhesion + experiment)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Trichoderma enzymes promote Fibrobacter succinogenes S85 adhesion to, and degradation of, complex substrates but not pure cellulose,

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2004
Diego P Morgavi
Abstract The effects of an enzyme preparation from Trichoderma longibrachiatum (TE) on adhesion and growth of the fibrolytic rumen bacterium Fibrobacter succinogenes S85 was studied to gain a better understanding of the action of feed enzyme additives on fibre digestion by ruminants. Adhesion experiments were performed on crystalline cellulose, corn silage and alfalfa hay. Adhesion of F succinogenes to cellulose was negatively related to the concentration of TE (p < 0.05). At the highest concentration used, TE reduced adhesion to cellulose from 65 to 39%. For corn silage and alfalfa hay, TE stimulated adhesion at low levels (p < 0.05) but this effect was lost at higher levels. Culture experiments were performed on crystalline cellulose and corn silage. The presence of TE in media containing cellulose failed to increase substrate disappearance or gas production although it increased numbers of non-adherent bacteria (p < 0.05). When corn silage was used, the addition of TE increased NDF disappearance (p < 0.05) at 24 and 48 h (33 and 52% in controls versus 53 and 65% in TE treatments). Growth rate and gas production were also stimulated (p < 0.05). We conclude that, for cellulose, the hydrolytic enzymes in TE obstructed available binding sites decreasing bacterial adherence. Fibrobacter succinogenes digested cellulose efficiently and addition of exogenous cellulases did not further increase substrate disappearance. However, for complex plant substrates, low concentration of TE increased bacterial adhesion and plant (corn) fiber degradation. For the Department of Agriculture and Agri-Food, Government of Canada, © Minister of Public Works and Government Services Canada 2004. Published for SCI by John Wiley & Sons, Ltd. [source]

Cover Picture: (Adv. Eng.

ADVANCED ENGINEERING MATERIALS, Issue 5 2010
Mater.
The INM - Leibniz Institute for New Materials in Saarbruecken engages in fundamental and applied materials research-from a chemical, physical and biological perspective. The cover highlights examples of INM's research which is presented in this special issue. The front cover shows biomineralization using the example of crystals embedded in the outer tissue of onion bulbs (courtesy of Birgit Heiland, INM). The back side demonstrates an in situ adhesion experiment in a scanning electron microscope (courtesy of Andreas S. Schneider/Anika Weber, INM). [source]

Alpha2beta1 integrin is the major collagen-binding integrin expressed on human Th17 cells

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2010
Marc Boisvert
Abstract Growing evidence indicates that collagen-binding integrins are important costimulatory molecules of effector T cells. In this study, we demonstrate that the major collagen-binding integrin expressed by human Th17 cells is alpha2beta1 (,2,1) or VLA-2, also known as the receptor for collagen I on T cells. Our results show that human naïve CD4+ T cells cultured under Th17 polarization conditions preferentially upregulate ,2,1 integrin rather than ,1,1 integrin, which is the receptor for collagen IV on T cells. Double staining analysis for integrin receptors and intracellular IL-17 showed that ,2 integrin but not ,1 integrin is associated with Th17 cells. Cell adhesion experiments demonstrated that Th17 cells attach to collagen I and collagen II using ,2,1 integrin but did not attach to collagen IV. Functional studies revealed that collagens I and II but not collagen IV costimulate the production of IL-17A, IL-17F and IFN-, by human Th17 cells activated with anti-CD3. These results identify ,2,1 integrin as the major collagen receptor expressed on human Th17 cells and suggest that it can be an important costimulatory molecule of Th17 cell responses. [source]

Basement membrane laminin-5 is deposited in colorectal adenomas and carcinomas and serves as a ligand for ,3,1 integrin

APMIS, Issue 3 2000
Jouni Lohi
Interplay between laminin-5 (Ln-5) and its integrin (Int) receptors ,2,1, ,3,1 and ,6,4 has been implicated in the progression and invasion of carcinomas. In this study we found abundant immuno-reactivity for chains of Ln-5 (,3-,3-,2) and Ln-10 (,5-,1), as well as for type VII collagen, in basement membranes (BM) of colorectal adenomas. In carcinomas of all differentiation grades, Lns were seen in tumor BMs, whereas type VII collagen was almost absent. Ln-5 appeared to accumulate along the invading edges of carcinomas, while Ln-10 was mostly absent. Immunoreactivity for Ln ,1 chain, a component of Lns-1 and -3, was not seen in adenomas or carcinomas. Immunoreactivity for ,2, ,6, ,1 and ,4 Ints was found in all tumors and that for ,3 Int in all adenomas and most of the carcinomas, often in colocalization with Ln-5. Immunoblotting of carcinoma tissues showed that the ,2 chain of Ln-5 was present as typical Mr 105000 and 155000 isoforms. Immunoprecipitation experiments showed production of Ln-5 by cultured colon carcinoma cells. In quantitative cell adhesion experiments, function-blocking MAbs to ,3 and ,1 Int subunits, but not those to Int ,2 or ,6 subunits, significantly inhibited the adhesion of cells to Ln-5. Our results suggest that BM composition in colorectal adenomas reflects the properties of surface epithelial BM of colorectal mucosa. In invading carcinomas, trimeric Ln-5, produced by carcinoma cells, is a major BM component and the cells use the ,3,1 Int complex for adhesion to Ln-5. [source]