Evaluation of Fermentation Efficiency of Yeast Strains and their Effect on Quality of Young Wines

The yeast has important role in fermentation of wine grapes and wine quality. The fermentation of wine grapes affect by efficiency of particular yeast strain, sugar content, pH, available temperature, etc. To evaluate the efficiency of yeast strains (Premier Cuvee, RS-1, RS-2, RS-3 and natural), present study was conducted on two wine grape varieties viz.; Sauvignon Blanc (White) and Cabernet Sauvignon (Red). Efficiency of yeast strains was evaluated in terms of conversion rate of sugar into alcohol. As per recorded data, strain RS-3 (Pichia kudriavzevii) was found more efficient than other strains in fermentation of Cabernet Sauvignon with efficiency of 84.4 per cent but in case of Sauvignon Blanc, the commercial culture Premier Cuevee was found superior over RS-3. The quality parameters of young wines of both the varieties were also affected by the used strains. Considering the efficiency and impact on various parameters of wines, local strain, i.e., RS-3 was found at par with commercial culture (Premier Cuvee). The RS-3 strain has potential to produce quality wines. However, studies on effects of RS-3 strain on some specific quality parameters of wines like varietal aroma compounds, flavours etc. are needed.     

A predictive aggregate transport model for microfiltration of combined macromolecular solutions and poly-disperse suspensions: testing model with transgenic goat milk

To meet the technical challenge of recovering human IgG fusion protein from transgenic whole goat milk at reasonable cost with high purity and yield, a predictive aggregate transport model for microfiltration has been developed (Baruah and Belfort, 2003). Here, to test the model's predictability of permeate flux and mass transport, a comprehensive series of experiments with varying wall shear rate, feed temperature, feed concentration, and module design are presented. A very good fit was obtained between the model predictions and measurements for a wide variety of experimental conditions. For microfiltration module design comparison, a linear hollow fiber module (representing current commercial technologies) gave lower permeation flux and higher yield than a helical hollow fiber module (representing the latest self-cleaning methodology). These results are easily explained with the model that is now being used to define operating conditions for maximizing performance. The procedure described by the model is generalizable and can be used to obtain optimal filtration performance for applications other than milk.     

Similar regulation of cell surface human T-cell leukemia virus type 1 (HTLV-1) surface binding proteins in cells highly and poorly transduced by HTLV-1-pseudotyped virions

Little is known about the requirements for human T-cell leukemia virus type 1 (HTLV-1) entry, including the identity of the cellular receptor(s). Previous studies have shown that although the HTLV receptor(s) are widely expressed on cell lines of various cell types from different species, cell lines differ dramatically in their susceptibility to HTLV-Env-mediated fusion. Human cells (293, HeLa, and primary CD4(+) T cells) showed higher levels of binding at saturation than rodent (NIH 3T3 and NRK) cells to an HTLV-1 SU immunoadhesin. A direct comparison of the binding of the HTLV-1 surface glycoprotein (SU) immunoadhesin and transduction by HTLV-1 pseudotyped virus revealed parallels between the level of binding and the titer for various cell lines. When cells were treated with phorbol myristate acetate (PMA), which down-modulates a number of cell surface molecules, the level of SU binding was markedly reduced. However, PMA treatment only slightly reduced the titer of murine leukemia virus(HTLV-1) on both highly susceptible and poorly susceptible cells. Treatment of target cells with trypsin greatly reduced binding, indicating that the majority of HTLV SU binding is to proteins. Polycations, which enhance the infectivity of several other retroviruses, inhibited HTLV-1 Env-mediated binding and entry on both human and rodent cells. These results suggest that factors other than the number of primary binding receptors are responsible for the differences in the titers of HTLV-1 pseudotypes between highly susceptible cells and poorly susceptible cells.     

Regulation of class II MHC gene expression by macrophages from Bcgr and Bcgs mice

The presence of class II mRNA was determined following stimulation of macrophages from Bcgr and Bcgs mice with rIFN-gamma. Despite the continuous expression of surface I-A glycoprotein by macrophages from Bcgr mice, class II mRNA was no longer present. The transient expression of I-A by macrophages from Bcgs mice, however, was accompanied by the disappearance of class II mRNA from the cells. Restimulation of macrophages from Bcgs mice, with rIFN-gamma resulted in the reappearance of class II mRNA and surface I-A expression. The reappearance of class II mRNA and the surface expression of I-A glycoprotein was inhibited by PGE2. These results indicate that differences in I-A expression by macrophages from Bcgr and Bcgs are not at the level of class II gene expression.     

Effect of growth temperature and media composition on the fatty acid composition of Bacillus stearothermophilus AN 002

The influence of growth temperature, media composition and cell age on the chemical composition of Bacillus stearothermophilus strain AN 002 has been determined. The total cellular protein decreased and the free amino acid content increased with growth temperature, in both exponential and stationary growth phase. The protein and free amino acid contents of cells were higher in the stationary phase than in the exponential phase, irrespective of growth temperature and media composition. The RNA content was only reduced in cells grown at 55° C. No significant variations were observed in the DNA and carbohydrate contents with respect to growth temperature and cell age. The total lipid and fatty acid compositions on the other hand varied as a function of growth temperature, cell age and media composition. Differences in the relative concentrations of even, odd and branched chain fatty acids were noticed. Novariation was observed in the antiiso and unsaturated fatty acids with respect to growth temperature. The unique variations in the fatty acid composition and total lipids at the growth temperature of 50° C and their variations in the stationary growth phase seem to be characteristic for B. stearothermophilus AN 002.     

Cysteine and serine protease-mediated proteolysis in body homogenate of a zooplankter, Moina macrocopa, is inhibited by the toxic cyanobacterium, Microcystis aeruginosa PCC7806

The paper describes the characterization of proteases in the whole body homogenate of Moina macrocopa, which can possibly be inhibited by the extracts of Microcystis aeruginosa PCC7806. With the use of oligopeptide substrates and specific inhibitors, we detected the activities of trypsin, chymotrypsin, elastase and cysteine protease. Cysteine protease, the predominant enzyme behind proteolysis of a natural substrate, casein, was partially purified by gel filtration. The substrate SDS-polyacrylamide gel electrophoresis of body homogenate revealed the presence of nine bands of proteases (17-72 kDa). The apparent molecular mass of an exclusive cysteine protease was 60 kDa, whereas of trypsin, it was 17-24 kDa. An extract of M. aeruginosa PCC7806 significantly inhibited the activities of trypsin, chymotrypsin and cysteine protease in M. macrocopa body homogenate at estimated IC(50) of 6- to 79-microg dry mass mL(-1). Upon fractionation by C-18 solid-phase extraction, 60% methanolic elute contained all the protease inhibitors, and these metabolites could be further separated by reverse-phase liquid chromatography. The metabolites inhibitory to M. macrocopa proteases also inhibited the corresponding class of proteases of mammalian/plant origin. The study suggests that protease inhibition may contribute to chemical interaction of cyanobacteria and crustacean zooplankton.     

Single Quantum Dot Tracking Reveals that an Individual Multivalent HIV-1 Tat Protein Transduction Domain Can Activate Machinery for Lateral Transport and Endocytosis

The mechanisms underlying the cellular entry of the HIV-1 Tat protein transduction domain (TatP) and the molecular information necessary to improve the transduction efficiency of TatP remain unclear due to the technical limitations for direct visualization of TatP''s behavior in cells. Using confocal microscopy, total internal reflection fluorescence microscopy, and four-dimensional microscopy, we developed a single-molecule tracking assay for TatP labeled with quantum dots (QDs) to examine the kinetics of TatP initially and immediately before, at the beginning of, and immediately after entry into living cells. We report that even when the number of multivalent TatP (mTatP)-QDs bound to a cell was low, each single mTatP-QD first locally induced the cell''s lateral transport machinery to move the mTatP-QD toward the center of the cell body upon cross-linking of heparan sulfate proteoglycans. The centripetal and lateral movements were linked to the integrity and flow of actomyosin and microtubules. Individual mTatP underwent lipid raft-mediated temporal confinement, followed by complete immobilization, which ultimately led to endocytotic internalization. However, bivalent TatP did not sufficiently promote either cell surface movement or internalization. Together, these findings provide clues regarding the mechanisms of TatP cell entry and indicate that increasing the valence of TatP on nanoparticles allows them to behave as cargo delivery nanomachines.     

Ca2+ dependence of the ATPase activity of phosphorylated smooth muscle myosin: effects of tropomyosin and actin

Calcium ions produce a 3-4-fold stimulation of the actin-activated ATPase activities of phosphorylated myosin from bovine pulmonary artery or chicken gizzard at 37 degrees C and at physiological ionic strengths, 0.12-0.16 M. Actins from either chicken gizzard or rabbit skeletal muscle stimulate the activity of phosphorylated myosin in a Ca2+-dependent manner, indicating that the Ca2+ sensitivity involves myosin or a protein associated with it. Partial loss of Ca2+ sensitivity upon treatment of phosphorylated gizzard myosin with low concentrations of chymotrypsin and the lack of any change on similar treatment of actin supports the above conclusion. Although both actins enhance ATPase activity, activation by gizzard actin exhibits Ca2+ dependence at higher temperatures or lower ionic strengths than does activation by skeletal muscle actin. The Ca2+ dependence of the activity of phosphorylated heavy meromyosin is about half that of myosin and is affected differently by temperature, ionic strength and Mg2+, being independent of temperature and optimal at lower concentrations of NaCl. Raising the concentration of Mg2+ above 2-3 mM inhibits the activity of heavy meromyosin but stimulates that of myosin, indicating that Mg2+ and Ca2+ activate myosin at different binding sites.     

Possible causes of the physiological decline in soybean nitrogen fixation in the presence of nitrate

Nodulated soybean plants (Glycine max (L.) Merr. cv. Clarke)were supplied with 10 mol m^-3 nitrate at the vegetative stage.This treatment caused a rapid decline in nitrogen fixation (acetylenereduction) activity and a consequent decline in ureides in thexylem sap. However, there was virtually no effect on the nitrogenasecomplex, according to Western blots against components 1 and2. The effect on nitrogen fixation was matched by a decreasein nitrogenase-linked respiration and increases in nodule oxygendiffusion resistance and the carbon cost of nitrogen fixation.The addition of nitrate had little effect on protein contentfrom either nodule plant or bacteroid fractions. Activitiesof nitrate reductase (NR) and nitrite reductase (NiR) from eitherthe plant fraction or the bacteroids were affected in differentways during 8 d of supply. Nodule plant NR and bacteroid NiR were not affected. However,nodule plant NiR increased 5-fold within 2 d of supplying Bacteroid NR only increased after6 d. These results could be interpreted in terms of a restrictednitrate access into the infected region of nodules. However,denitrification was detected within 2 d of nitrate supply insoybean nodules. The results are discussed in relation to possiblecauses of the nitrate-induced decline in nitrogenase activity. Key words: Glycine max, nitrate, nitrogen fixation, nodules