Synthesis of fruity ethyl esters by acyl coenzyme A: alcohol acyltransferase and reverse esterase activities in Oenococcus oeni and Lactobacillus plantarum.

AIMS: To assess the abilities of commercial wine lactic acid bacteria (LAB) to synthesize potentially flavour active fatty acid ethyl esters and determine mechanisms involved in their production. METHODS AND RESULTS: Oenococcus oeni AWRI B551 produced significant levels of ethyl hexanoate and ethyl octanoate following growth in an ethanolic test medium, and ester formation generally increased with increasing pH (4.5 > 3.5), anaerobiosis and precursor supplementation. Cell-free extracts of commercial O. oeni strains and Lactobacillus plantarum AWRI B740 were also tested for ester-synthesizing capabilities in a phosphate buffer via: (i) acyl coenzyme A: alcohol acyltransferase (AcoAAAT) activity and (ii) reverse esterase activity. For both ester-synthesizing activities, strain-dependent variation was observed, with AcoAAAT activity generally greater than reverse esterase. Reverse esterase in O. oeni AWRI B551 also esterified 1-propanol to produce propyl octanoate, and deuterated substrates ([(2)H(6)]ethanol and [(2)H(15)]octanoic acid) to produce the fully deuterated ester, [(2)H(5)]ethyl [(2)H(15)]octanoate. CONCLUSIONS: Wine LAB exhibit ethyl ester-synthesizing capability and possess two different ester-synthesizing activities, one of which is associated with an acyl coenzyme A: alcohol acyltransferase. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that wine LAB exhibit enzyme activities that can augment the ethyl ester content of wine. This knowledge will facilitate greater control over the impacts of malolactic fermentation on the fruity sensory properties and quality of wine.

Psoriatic arthritis joint fluids are characterized by CD8 and CD4 T cell clonal expansions appear antigen driven.

The CD8 alphabetaT cell receptor repertoire in joint fluid of individuals with active psoriatic arthritis contained an average of 32 major oligoclonal expansions in many variable genes of the TCR beta chain (BV) families, as shown by beta-chain CDR3 length analysis. Interestingly, a small number of oligoclonal expansions were shared between simultaneous samples of joint fluid and blood; however, most expansions found in joint fluid were not identifiable in blood emphasizing the immunologic specificity of the clonal events for the inflamed joint at a given point of time. The CD4 T cell joint fluid repertoire contained fewer and smaller oligoclonal expansions also largely restricted to the joint, suggesting that CD4 T cells participate perhaps by interacting cognitively to generate the CD8 clones. The inferred amino acid sequence of a single CD8 oligoclonal expansion revealed that they usually are composed of one or a few structurally related clones at the amino acid sequence level with beta-chains that encode identical or highly homologous CDR3 motifs. These were not shared among patients. Moreover, several clones that encoded the same amino acid sequence were found to be structurally distinct at the nucleotide level, strongly implying clonal selection and expansion is operating at the level of specific TCR-peptide interactions. The findings support a model of psoriatic arthritis inflammation involving extensive and selective Ag, likely autoantigen, driven intra-articular CD4, and CD8 T cell clonal expansions.

Changes in peripheral blood double-negative T-lymphocyte (CD3+ CD4- CD8-) populations associated with acute cellular rejection after liver transplantation.

Circulating CD3+ T lymphocytes that express neither the CD4 nor CD8 surface molecules (double-negative T lymphocytes) are phenotypically and functionally distinct from single-positive CD3+CD4+ and CD3+CD8+ lymphocytes and are thought to represent a distinct T-cell lineage. The presence of low numbers of double-negative T cells in healthy individuals and the increase observed in association with lymphoproliferative disorders, graft-versus-host disease, and autoimmune diseases suggest a pathogenic or immunoregulatory role for this population of T lymphocytes. In this study, peripheral blood double-negative T cells were assessed quantitatively using three-color flow cytometry in 10 patients after liver transplantation during a 6-week period. During this time, 12 episodes of histologically proven acute cellular rejection occurred in 8 patients. The median postoperative baseline double-negative T-cell count expressed as a proportion of the CD3+ T cells was 2.4 +/- 1.2 (median +/- SD; n = 10), which was identical to a control group of healthy adults (2.5 +/- 2.4; n = 9). Circulating numbers of double-negative T cells were increased significantly during acute cellular rejection (6.8 +/- 6.7; P < .001; n = 12). After pulse corticosteroid therapy for rejection, there was a significant decrease in the double-negative T-cell population (3.5 +/- 5.0 v 6.8 +/- 6.7; P = .01). No significant changes occurred in the double-negative T-cell count in the absence of clinical events (2.4 +/- 3.5; n = 73). These findings are consistent with a role for double-negative T cells in the initiation of acute cellular rejection or a possible regulatory role in the immunologic changes associated with rejection.

Dental health status of mentally and physically handicapped children and adults in the Galway Community Care Area of the Western Health Board.

An epidemiological survey was carried out to assess the treatment needs on the mentally and physically handicapped in the Galway Community Care Area. The survey was conducted by both questionnaire and clinical examination. The results of the survey indicate that the pattern of dental caries for the mentally and physically handicapped children is similar to that for the rest of the child population in Ireland. The results also show that extraction has been the treatment of choice for the mentally and physically handicapped. The periodontal assessment of the handicapped adult population found that moderate pocketing accounted for the bulk of periodontal disease present.

Image analysis method for the rapid counting of Saccharomyces cerevisiae cells.

An image analysis system which incorporates a microscope, video camera, monitor, and Apple computer and which uses image area to count Saccharomyces cerevisiae cells is described and evaluated. Yeast cell suspensions of densities of up to 100 X 10(6) cells per ml can be counted when viewed in the counting chamber of a hemacytometer. The yeast image area measured depends upon the light intensity used to illuminate the yeast cells, the sharpness of the image focused on the monitor, and the grey level selected when scanning the digitized image on the monitor of the Apple computer, all of which can be controlled. The image area also depends upon the yeast strain and medium in which the culture is grown, but it is not affected by the concentration of sugar or ethanol in which the yeast cells are suspended. Yeast growth measured by image analysis can be calibrated to give results similar to those obtained with hemacytometer counting. Yeast cells can be counted in the presence of high cell densities of bacteria by adjusting the grey level at which the digitized image is scanned.