Effect of Added Fat and Calcium on in Vitro Formation of Insoluble Fatty Acid Soaps and Cell Wall Digestibility

The in vitro cell wall digestibility and chemical composition were determined with a total of 56 forage samples. Two samples each of Dactylis glomerata L., Bromus inermis Leyss., Medicago sativa L., and Lotus corniculatus L. were collected at three maturities. Two samples of Symphtum officinale L. were collected at two maturities. All samples were later separated into leaf and stem portions. Wide variation existed in chemical composition and digestibility. The range in cell wall constituents was 23.9 to 79.8%, in acid detergent fiber 16.9 to 52.3%, and in lignin 3.7 to 19.1%. The in vitro cell wall digestibility varied from 16.6 to 77.5%. Correlation coefficients between lignin content and cell wall digestibility were higher when lignin was expressed as a percentage of dry matter rather than as a percentage of cell walls. In grasses, the relationship between lignin in cell walls and cell wall digestibility was linear. However, cell wall digestibility of legumes and Russian comfrey was not as low as expected from the content of lignin.

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Influence of growth temperature on anatomy and in vitro digestibility of maize tissues

The Journal of Agricultural Science ◽

10.1017/s002185960007221x ◽

1990 ◽

Vol 114 (2) ◽

pp. 207-212 ◽

Cited By ~ 22

Author(s):

J. W. Cone ◽

F. M. Engels

Keyword(s):

Cell Wall ◽

Temperature Regime ◽

Lignin Content ◽

Chemical Properties ◽

Wall Layer ◽

Cell Diameter ◽

In Vitro Digestibility ◽

Cell Wall Digestibility ◽

Temperature Regimes

SUMMARYTissues of maize grown under different temperature regimes showed remarkable differences in anatomical and chemical properties and in vitro digestibility. A high temperature regime (12 h at 30 °C and 12 h at 24 °C) resulted in decreased cell wall thickness, cell diameter and cell wall yield, doubled lignin content and decreased in vitro digestibility, compared with plants grown under a low temperature regime (12 h at 18 °C and 12 h at 12 °C). A reduction in intensity of staining for lignin was observed in plants grown at 30/24 °C. Cell wall digestibility was thought to be limited by an indigestible cell wall layer between the secondary walls of adjacent cells. The use of lignin staining was of limited value for predicting cell wall digestibility. High temperatures probably affect physiological processes leading to lignin formation and deposition.

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Possible Association of GroES and Antigen 85 Proteins with Heat Resistance of Mycobacterium paratuberculosis

Applied and Environmental Microbiology ◽

10.1128/aem.70.3.1688-1697.2004 ◽

2004 ◽

Vol 70 (3) ◽

pp. 1688-1697 ◽

Cited By ~ 18

Author(s):

Nackmoon Sung ◽

Kuni Takayama ◽

Michael T. Collins

Keyword(s):

Cell Wall ◽

Fatty Acid ◽

Heat Resistance ◽

Culture Medium ◽

Culture Conditions ◽

Soluble Proteins ◽

The Other ◽

Mycolic Acids ◽

Antigen 85

ABSTRACT Conflicting reports on the heat resistance of Mycobacterium paratuberculosis prompted an examination of the effect of culture medium on this property of the organism. M. paratuberculosis was cultured in three types of media (fatty acid-containing medium 7H9-OADC (oleic acid-albumin-dextrose-catalase supplement) and glycerol-containing media WR-GD and 7H9-GD [glycerol-dextrose supplement]) at pH 6.0. M. paratuberculosis grown under these three culture conditions was then tested for heat resistance in distilled water at 65Ã¯Â¿Â½C. Soluble proteins and mycolic acids of M. paratuberculosis were evaluated by two-dimensional electrophoresis (2-DE) and thin-layer chromatography (TLC), respectively. The type of culture medium used significantly affected the heat resistance of M. paratuberculosis. The decimal reduction times at 65Ã¯Â¿Â½C (D 65Ã¯Â¿Â½C values; times required to reduce the concentration of bacteria by a factor of 10 at 65Ã¯Â¿Â½C) for M. paratuberculosis strains grown in 7H9-OADC were significantly higher than those for the organisms grown in WR-GD medium (P < 0.01). When the glycerol-dextrose supplement of WR was substituted for the fatty acid supplement (OADC) in 7H9 medium (resulting in 7H9-GD), the D 65Ã¯Â¿Â½C value was significantly lower than that for the organism grown in 7H9-OADC medium (P = 0.022) but higher than that when it was cultured in WR-GD medium (P = 0.005). Proteomic analysis by 2-DE of soluble proteins extracted from M. paratuberculosis grown without heat stress in the three media (7H9-OADC, 7H9-GD, and WR-GD) revealed that seven proteins were more highly expressed in 7H9-OADC medium than in the other two media. When the seven proteins were subjected to matrix-assisted laser desorption ionization-mass spectrometric analysis, four of the seven protein spots were unidentifiable. The other three proteins were identified as GroES heat shock protein, alpha antigen, and antigen 85 complex B (Ag85B; fibronectin-binding protein). These proteins may be associated with the heat resistance of M. paratuberculosis. Alpha antigen and Ag85B are both trehalose mycolyltransferases involved in mycobacterial cell wall assembly. TLC revealed that 7H9-OADC medium supported production of more trehalose dimycolates and cell wall-bound mycolic acids than did WR-GD medium. The present study shows that in vitro culture conditions significantly affect heat resistance, cell wall synthesis, and protein expression of M. paratuberculosis and emphasize the importance of culture conditions on in vitro and ex vivo studies to estimate heat resistance.

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Interaction of lipid supply and carbohydrates in the diet of sheep with digestibility and ruminal digestion

The Journal of Agricultural Science ◽

10.1017/s0021859600078254 ◽

1991 ◽

Vol 116 (3) ◽

pp. 437-445 ◽

Cited By ~ 10

Author(s):

Y. Elmeddah ◽

M. Doreau ◽

B. Michalet-Doreau

Keyword(s):

Cell Wall ◽

Organic Matter ◽

Fatty Acid ◽

Acid Content ◽

Dry Matter ◽

Volatile Fatty Acids ◽

Fatty Acid Content ◽

Maize Silage ◽

Cell Wall Digestibility ◽

In Sacco

SUMMARYTwo groups of nine wethers, three of which were fitted with rumen cannulas, were used in a digestion trial at the INRA centre in Theix, France, in 1988. Group 1 received 65% maize silage and 35% concentrates; group 2 received 65% hay and 35% concentrates. Concentrates were based on either cereals rich in starch, or by-products rich in fibre and were given either alone or supplemented with lipids as calcium soaps. The fatty acid content of lipid-supplemented diets wasc.9·5 and 8·5% of dry matter, of which 85 and 89% was provided by calcium soaps, for maize silage and hay diets, respectively. For each group, the four diets were tested in four successive periods from January to June 1988.Total digestibility of dry and organic matter, acid detergent fibre (ADF) and neutral detergent fibre (NDF) was measured in six wethers of each group by total faeces collection. On cannulated wethers, volatile fatty acid content and composition, pH and NH3-N in rumen liquor were determined four times a day;in saccodegradability of dry matter, ADF and NDF of the forage eaten by the wethers was estimated by the kinetics of incubation in the rumen.In vivoandin saccoresults showed that dry matter and organic matter digestibilities were not modified by the nature of concentrates. Cell wall digestibility was higher for fibre concentrates than for starchy concentrates, by 4·1 and 6·2 percentage units for NDF in maize silage and hay groups, respectively. Volatile fatty acids (VFA) and ammonia concentrations were higher and pH was lower with the maize silage than with the hay diet.Lipid supply slightly increased cell wall digestibility in the group fed maize silage by 7·5 and 2·0 percentage units for starch and fibre concentrates, respectively. This surprising increase was related to an improvement inin saccodegradability. In all diets, lipid supply increased pH, but variations in VFA concentration and pattern were low. Interactions between the nature of concentrate and lipid supply were moderate, but were higher in the group fed maize silage than in the group fed hay, especially for total digestibility.

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In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083035 ◽

1978 ◽

Vol 36 (2) ◽

pp. 434-435

Author(s):

D. Reis ◽

B. Vian ◽

J. C. Roland

Keyword(s):

Cell Wall ◽

Self Assembly ◽

Plant Cell Wall ◽

Higher Plants ◽

Three Dimensional ◽

Cytochemical Study ◽

Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169110 ◽

1994 ◽

Vol 52 ◽

pp. 276-277

Author(s):

Mary Beth Downs ◽

Wilson Ribot ◽

Joseph W. Farchaus

Keyword(s):

Cell Wall ◽

Molecular Sieves ◽

Cell Envelope ◽

Single Species ◽

Supporting Cell ◽

Surface Layers ◽

Rabbit Igg ◽

In Vitro Assembly ◽

Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

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In Vitro Incorporation and Metabolism of Icosapentaenoic and Docosahexaenoic Acids in Human Platelets - Effect on Aggregation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661603 ◽

1986 ◽

Vol 56 (01) ◽

pp. 057-062 ◽

Cited By ~ 56

Author(s):

Martine Croset ◽

M Lagarde

Keyword(s):

Arachidonic Acid ◽

Fatty Acid ◽

Platelet Aggregation ◽

Fatty Acid Distribution ◽

Thromboxane A2 ◽

Human Platelets ◽

Aggregation Response ◽

Docosahexaenoic Acids ◽

Membrane Level

SummaryWashed human platelets were pre-loaded with icosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or EPA + DHA and tested for their aggregation response in comparison with control platelets. In fatty acid-rich platelets, an inhibition of the aggregation could be observed when induced by thrombin, collagen or U-46619. The strongest inhibition was observed with DHA-rich platelets and it was reduced when DHA was incorporated in the presence of EPA.Study of fatty acid distribution in cell lipids after loading showed that around 90% of EPA or DHA taken up was acylated into phospholipids and a very small amount (less than 2%) remained in their free and hydroxylated forms. DHA was more efficiently acylated into phosphatidylethanolamine (PE) than into phosphatidylinositol (PI) in contrast to what observed with EPA, and both acids were preferentially incorporated into phosphatidylcholine (PC). EPA inhibited total incorporation of DHA and increased its relative acylation into PE at the expense of PC. In contrast, DHA did not affect the acylation of EPA. Upon stimulation with, thrombin, EPA was liberated from phospholipids and oxygenated (as judged by the formation of its monohydroxy derivative) whereas DHA was much less metabolized, although consistently transferred into PE.It is concluded that EPA and DHA might affect platelet aggregation via different mechanisms when pre-loaded in phospholipids. Whereas EPA is known to alter thromboxane A2 metabolism from endogenous arachidonic acid, by competing with it, DHA might act directly at the membrane level for inhibiting aggregation.

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