SKRINING GEN GLUKOSILTRANSFERASE (GTF) DARI BAKTERI ASAM LAKTAT PENGHASIL EKSOPOLISAKARIDA

Screening for glucosyltransferase gene (gtf) from exopolysaccahride producing lactic acid bacteria. Glucosyltransferase (GTF) is an enzyme involved in exopolysaccharide (EPS) polymer synthesis in microbes. One example of EPS that has been used in pharmaceutical and medical application is dextran. Dextran has been used in conjugated-drug delivery system as matrix. As a group of microbes producing EPS, lactic acid bacteria (LAB) have been well reported carrying sucrase genes glucosyltransferase (gtf), as well as fructosyltransferases (ftf). In an attempt to search for novel gtf genes as the aim of this study, LAB collection isolated from local sources yielded from previous study were screened performing PCR using degenerate primers DegFor and DegRev. An approximately 660 base pairs (bp) amplicons were obtained by using genomic DNAs of those LAB isolates as templates with conserved region of gtf genes catalytic domain as target. Two out of 20 LAB strains were yielded no amplicon as observed on agarose gel, while one strain exhibited non-specific amplicon DNA bands with sizes other than 660 bp. The two negative ones were isolated from soil obtained from dairy product waste field and from waste of soy sauce from previous study, while the latter was isolated from waste of soy sauce. Keywords: glucosyltransferase, gtf, exopolysaccharide, lactic acid bacteria, degenerate primer

Seleksi Galur-Galur Leuconostoc Yang Mempunyai Aktivitas Bakteriostatin Terhadap Berbagai Bakteri Indikator

Lactid Acid Bacteria (LAB) are known to produce bacteriocins which have antimicrobi- al activity, and possessed to be developed as antibiotic complement. This study aimed to characterize bacteriocins activity from Leuconostoc strains isolated previously from local sources, and to optimize pH and incubation temperature as well. A well diffusion agar assay for zone inhibition method and bacteriocin potency assay performing minimum in- hibition concentration (MIC) have been done. Bacterial indicators used in this study are Leu. mesenteroides TISTR 120, and JCM 6124, Staphylococcus aureus FNCC 0047, Lis- teria monocytogenes FNCC 0156, Escherichia coli FNCC 0183, Pseudomonas aeruginosa FNCC 0063, Salmonella typhi FNCC 0165 and Bacillus subtilis FNCC 0061. Catalase, Trypsin and Protease K were also used for confirmation test. Results revealed that both Leu. mesenteroides MBF2-5 and MBF7-17 possessed bacteriocin activity although against Leu. mesenteroides TISTR 120 and JCM 6124 indicators strains. The optimum pH for bacteriocin potency assay for both Leuconostoc strains MBF2-5 and MBF7-17 was pH 6, whereas the optimum incubation temperature was 32 oc with MIC value of 90% and 80%, respectively

Do Philippine Stocks Catch Coronavirus? Some Econometric Check-up on Pandemic Data, 2021-2022

Using daily data from March 1, 2021 to March 31, 2022, the USD-PHP exchange rate and pandemic-related variables such as the number of cases, vaccinations, and stringency index in relation to the movements of Philippine Stock Exchange index (PSEi) were investigated. The paper views vaccination as an instrument for reducing economic uncertainty, subsequently providing a positive sentiment for investors and stock market. Ordinary least squares, autoregressive distributed lags, and vector autoregression was used to show some dynamics based on time series data. Particularly, there are indications of reported cases being negatively correlated and statistically significant for PSEi. Further, impulse response functions show that unanticipated shocks in vaccination and exchange rate temporarily affect the stock market index. Conversely, long-lasting effects were found for shocks in Covid-19 cases and stringency index. Overall, all the variables in the study only accounted for a small portion of explaining the fluctuations and movements of PSEi

Screening for Glucosyltransferase gene (gtf) from exopolysaccahride producing lactic acid bacteria

Glucosyltransferase (GTF) is an enzyme involved in exopolysaccharide (EPS) polymer synthesis in microbes. One example of EPS that has been used in pharmaceutical and medical application is dextran. Dextran has been used in conjugated-drug delivery system as matrix. As a group of microbes producing EPS, lactic acid bacteria (LAB) have been well reported carrying sucrase genes glucosyltransferase (gtf), as well as fructosyltransferases (ftf). In an attempt to search for novel gtf genes as the aim of this study, LAB collection isolated from local sources yielded from previous study were screened performing PCR using degenerate primers DegFor and DegRev. An approximately 660 base pairs (bp) amplicons were obtained by using genomic DNAs of those LAB isolates as templates with conserved region of gtf genes catalytic domain as target. Two out of 20 LAB strains were yielded no amplicon as observed on agarose gel, while one strain exhibited non-specific amplicon DNA bands with sizes other than 660 bp. The two negative ones were isolated from soil obtained from dairy product waste field and from waste of soy sauce from previous study, while the latter was isolated from waste of soy sauce

4,6-α-Glucanotransferase, a Novel Enzyme That Structurally and Functionally Provides an Evolutionary Link between Glycoside Hydrolase Enzyme Families 13 and 70▿

Lactobacillus reuteri 121 uses the glucosyltransferase A (GTFA) enzyme to convert sucrose into large amounts of the α-d-glucan reuteran, an exopolysaccharide. Upstream of gtfA lies another putative glucansucrase gene, designated gtfB. Previously, we have shown that the purified recombinant GTFB protein/enzyme is inactive with sucrose. Various homologs of gtfB are present in other Lactobacillus strains, including the L. reuteri type strain, DSM 20016, the genome sequence of which is available. Here we report that GTFB is a novel α-glucanotransferase enzyme with disproportionating (cleaving α1→4 and synthesizing α1→6 and α1→4 glycosidic linkages) and α1→6 polymerizing types of activity on maltotetraose and larger maltooligosaccharide substrates (in short, it is a 4,6-α-glucanotransferase). Characterization of the types of compounds synthesized from maltoheptaose by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), methylation analysis, and 1-dimensional 1H nuclear magnetic resonance (NMR) spectroscopy revealed that only linear products were made and that with increasing degrees of polymerization (DP), more α1→6 glycosidic linkages were introduced into the final products, ranging from 18% in the incubation mixture to 33% in an enriched fraction. In view of its primary structure, GTFB clearly is a member of the glycoside hydrolase 70 (GH70) family, comprising enzymes with a permuted (β/α)8 barrel that use sucrose to synthesize α-d-glucan polymers. The GTFB enzyme reaction and product specificities, however, are novel for the GH70 family, resembling those of the GH13 α-amylase type of enzymes in using maltooligosaccharides as substrates but differing in introducing a series of α1→6 glycosidic linkages into linear oligosaccharide products. We conclude that GTFB represents a novel evolutionary intermediate between the GH13 and GH70 enzyme families, and we speculate about its origin