Dispersive Liquid-Liquid Microextraction for the Quantitation of Terpenes in Wine

To study the contribution of yeasts to the formation of terpene derivatives during winemaking, a dispersive liquid-liquid microextraction gas chromatography mass spectrometry method was developed for the quantitation of terpenes in white wines, synthetic wine, and a fermented synthetic medium. A mixture of acetone (disperser solvent) and dichloromethane (extraction solvent) was added to 5 mL of sample. The proposed method showed no matrix effect, good linearity in the enological range (from 10 to 200 μg/L), good recovery, and satisfactory inter- and intraday reproducibilities (below 20 and 15% of the relative standard deviation). This sample preparation technique is very interesting for high-throughput studies and economic and environmental reasons because it is fast and easy to operate with high enrichment and consumes a low volume of organic solvents. This method was applied to explore the capacities of 40 yeast strains to produce terpene compounds during fermentation of Chardonnay and Ugni Blanc musts as well as in a synthetic medium. Interestingly, most of the studied compounds were detected and quantified in the resulting wines. This study shows that yeast strains can intrinsically produce terpene derivatives under enological conditions and also highlights the differences between the de novo biosynthesis of terpenes and their precursor-linked production.

Natural skin surface pH is on average below 5, which is beneficial for its resident flora

Variable skin pH values are being reported in literature, all in the acidic range but with a broad range from pH 4.0 to 7.0. In a multicentre study (N = 330), we have assessed the skin surface pH of the volar forearm before and after refraining from showering and cosmetic product application for 24 h. The average pH dropped from 5.12 +/- 0.56 to 4.93 +/- 0.45. On the basis of this pH drop, it is estimated that the 'natural' skin surface pH is on average 4.7, i.e. below 5. This is in line with existing literature, where a relatively large number of reports (c. 50%) actually describes pH values below 5.0; this is in contrast to the general assumption, that skin surface pH is on average between 5.0 and 6.0. Not only prior use of cosmetic products, especially soaps, have profound influence on skin surface pH, but the use of plain tap water, in Europe with a pH value generally around 8.0, will increase skin pH up to 6 h after application before returning to its 'natural' value of on average below 5.0. It is demonstrated that skin with pH values below 5.0 is in a better condition than skin with pH values above 5.0, as shown by measuring the biophysical parameters of barrier function, moisturization and scaling. The effect of pH on adhesion of resident skin microflora was also assessed; an acid skin pH (4-4.5) keeps the resident bacterial flora attached to the skin, whereas an alkaline pH (8-9) promotes the dispersal from the skin.

Vanillin production from simple phenols by wine-associated lactic acid bacteria

AIMS

The ability of lactic acid bacteria (LAB) to metabolize certain phenolic precursors to vanillin was investigated.

METHODS AND RESULTS

Gas chromatography-mass spectrometry (GC-MS) or HPLC was used to evaluate the biosynthesis of vanillin from simple phenolic precursors. LAB were not able to form vanillin from eugenol, isoeugenol or vanillic acid. However Oenococcus oeni or Lactobacillus sp. could convert ferulic acid to vanillin, but in low yield. Only Lactobacillus sp. or Pediococcus sp. strains were able to produce significant quantities of 4-vinylguaiacol from ferulic acid. Moreover, LAB reduced vanillin to the corresponding vanillyl alcohol.

CONCLUSIONS

The transformation of phenolic compounds tested by LAB could not explain the concentrations of vanillin observed during LAB growth in contact with wood.

SIGNIFICANCE AND IMPACT OF THE STUDY

Important details of the role of LAB in the conversion of phenolic compounds to vanillin have been elucidated. These findings contribute to the understanding of malolactic fermentation in the production of aroma compounds.

A novel antiapoptotic mechanism based on interference of Fas signaling by CD44 variant isoforms

There is growing evidence that one of the central common characteristics of tumor and inflammatory cells is their resistance to programmed cell death. This feature results in the accumulation of harmful cells, which are mostly refractory to Fas (FAS, APO-1)-mediated apoptosis. A molecule found on these cells is the transmembrane receptor CD44 with its variant isoforms (CD44v). The establishment of transfectants expressing different CD44v isoforms allowed us to demonstrate that the CD44v6 and CD44v9 isoforms exhibit an antiapoptotic effect and can block Fas-mediated apoptosis. Moreover, we observed that CD44v6 and CD44v9 colocalize and interact with Fas. Importantly, an anti-CD44v6 antibody can abolish the antiapoptotic effect of CD44v6. These results are the first to show that CD44v isoforms interfere with Fas signaling. Our findings improve the understanding of the pathogenesis of cancer and autoimmunity and open new strategies to treat such disorders.

Malignant transformation of monoclonal gammopathy of undetermined significance: cumulative incidence and prognostic factors

The cumulative incidence of malignant transformation was studied in 88 patients with monoclonal gammopathy of undetermined significance (MGUS) that had a complete prospective follow-up. At a median follow-up of 6.75 years, 10 patients developed multiple myeloma (MM) (11.4%) and 2 developed immunocytoma (2.3%). The cumulative incidence of malignant transformation was 9.1, 21.3, 38 and 48.3% at 5, 10, 15 and 20 years, respectively. In univariate analysis on 102 MGUS patients, M-component level, bone marrow plasma cell percentage and kappa light chain correlated significantly with the development of a malignancy (p=0.0289, 0.0265 and 0.0013, respectively). In multivariate analysis, light chain type of M-component and plasma cell percentage had independent prognostic significance. A high-risk (M-component level > 10 g/l and/or plasma cell percentage > 2%) and a low-risk group ( M-component level < 10 g/l and/or plasma cell percentage < 2%) of MGUS patients was identified, which differed significantly in the cumulative incidence of developing a malignancy (p<0.001 for M-component level and p=0.007 for plasma cell percentage). These results imply that high-risk patients should receive a more frequent follow-up, in comparison to low-risk patients.

Consensus strategy to quantitate malignant cells in myeloma patients is validated in a multicenter study. Belgium-Dutch Hematology-Oncology Group

Recently the Belgium-Dutch Hematology-Oncology group initiated a multicenter study to evaluate whether myeloma patients treated with intensive chemotherapy benefit from additional peripheral stem cell transplantation. To determine treatment response accurately, we decided to quantitate malignant cells. To test a consensus quantitation strategy, 5 centers independently determined the immunoglobulin heavy chain sequences of patient tumor cells and developed allele-specific oligonucleotides (ASO) and ASO-polymerase chain reaction (PCR). We compared the reproducibility of real-time quantitation with quantitation using limiting dilutions. We distributed DNA samples with a 4-log range of tumor cell concentrations and found average quantitation values deviating 74% and 42% from the input values with real-time PCR (1 center) and limiting dilutions (4 centers), respectively. Within single centers we found an average variation coefficient of 0.74, with limiting dilutions not significantly different from the average 0.82 center-to-center variation coefficient. Within a single center, real-time quantitation proved more reproducible (average variation coefficient, 0.36). Quantification was confirmed in 3 patients during treatment in the protocol. This report shows that real-time PCR or limiting dilution assays can be used for quantitation in a single multicenter trial. We present a consensus strategy that allows an accurate comparison of quantitation data generated in independent centers.

Bcl-2 antisense therapy in multiple myeloma

Multiple myeloma is a plasma cell tumor localised in the bone marrow. During chemotherapy drug resistance develops in almost all patients. We have indications that the anti-apoptopic protein Bcl-2 is a key element in multi drug resistance in myeloma. Reduction of Bcl-2 renders the tumor cell susceptible to drug induced apoptosis. This suggests that therapies directed at lowering Bcl-2 levels in myeloma cells in vivo, like Bcl-2 antisense treatment, might chemosensitize the tumor cells and therefore might be applicable for therapeutic use.

Generation of the (auto)-antibody repertoire: a case of narcissism?

The immune system has the tremendous task of recognizing and eliminating a practically unlimited number of foreign and often harmful substances. To reach that goal, it has evolved as an apparatus generating a vast array of different antigen receptors expressed by T and B lymphocytes. Through these receptors, the cells can recognize, and respond to, foreign structures; nevertheless, the lymphocytes do not normally react to the body's own constituents. The processes that safeguard a sufficiently broad diversity and yet prevent potentially pathogenic autoimmune reactivity are only now beginning to be elucidated. We describe some of the mechanisms that are believed to play a major role in the generation of the B lymphocyte and antibody repertoire, the induction of tolerance against autologous components and the production of pathogenic autoantibodies, once tolerance is broken.

Human immune response to group A streptococcal carbohydrate (A-CHO). II. Antigen-independent stimulation of IgM anti-A-CHO production in purified B cells by a monoclonal anti-idiotopic antibody

The paper describes the induction by a monoclonal anti-idiotopic antibody (anti-Id mAb) of specific antibody production to group A streptococcal carbohydrate (A-CHO) in purified human B cells of several unrelated individuals. The anti-Id mAb, designated 16F498 (anti-Id498), recognizes a recurrent idiotope (Id 498) associated with the combining site of human antibodies to N-acetyl-D-glucosamine (GlcNAc), the immunodominant group of A-CHO. Id498 is expressed on IgM anti-GlcNAc antibodies but does not occur on IgG antibodies with the same specificity. It occurs also on a minor population of IgM antibodies without specificity for A-CHO. Id498 was found in 19 of 27 sera from unselected healthy donors and thus seems to be frequently expressed within the adult B cell repertoire. The in vitro induction of anti-A-CHO antibodies was analyzed in human B cells extensively depleted for T cells. Specific antibody secretion required cross-linked anti-Id which was achieved by coupling the mAb to agarose beads. No antibody secretion could be induced by soluble anti-Id (1 and 10 micrograms/ml). An optimal response required soluble T cell-derived factors which were added as a mixture of recombinant interleukin 2 with a T cell hybridoma supernatant that augments B cell growth and differentiation. Under these conditions an antigen-independent specific increase of IgM anti-A-CHO production (2.6- to 10-fold, or up to 2000 ng/ml respectively) could be induced in blood B cell populations of four of six normal individuals expressing the Id498 at serum level.

Human immune response to group A streptococcal carbohydrate (A-CHO). II. Antigen-independent stimulation of IgM anti-A-CHO production in purified B cells by a monoclonal anti-idiotopic antibody

The paper describes the induction by a monoclonal anti-idiotopic antibody (anti-Id mAb) of specific antibody production to group A streptococcal carbohydrate (A-CHO) in purified human B cells of several unrelated individuals. The anti-Id mAb, designated 16F498 (anti-Id498), recognizes a recurrent idiotope (Id 498) associated with the combining site of human antibodies to N-acetyl-D-glucosamine (GlcNAc), the immunodominant group of A-CHO. Id498 is expressed on IgM anti-GlcNAc antibodies but does not occur on IgG antibodies with the same specificity. It occurs also on a minor population of IgM antibodies without specificity for A-CHO. Id498 was found in 19 of 27 sera from unselected healthy donors and thus seems to be frequently expressed within the adult B cell repertoire. The in vitro induction of anti-A-CHO antibodies was analyzed in human B cells extensively depleted for T cells. Specific antibody secretion required cross-linked anti-Id which was achieved by coupling the mAb to agarose beads. No antibody secretion could be induced by soluble anti-Id (1 and 10 micrograms/ml). An optimal response required soluble T cell-derived factors which were added as a mixture of recombinant interleukin 2 with a T cell hybridoma supernatant that augments B cell growth and differentiation. Under these conditions an antigen-independent specific increase of IgM anti-A-CHO production (2.6- to 10-fold, or up to 2000 ng/ml respectively) could be induced in blood B cell populations of four of six normal individuals expressing the Id498 at serum level.