SPECTRAL EVALUATION AND ANTIMICROBIAL ACTIVITY OF SYNTHESIZED 4H-1,4-BENZOTHIAZINES

Objective: 4H-1,4-Benzothiazines constitute an important class of heterocycles containing 1,4-thiazine ring fused to benzene ring. They are extensively used as tranquilizer, antispasmodic, central nervous system depressant, antiulcer, antibacterial, antifungal, antioxidant, anticancer agents, fungicides, etc. Therefore, these observations prompted us to synthesize substituted 4H-1,4-benzothiazines and investigate their antimicrobial activity against selected bacterial and fungal strains. Methods: In the present research work, 2-Amino-3,5,6-trichlorobenzenethiol condensed with β-diketones/β-ketoesters in the presence of dimethyl sulfoxide followed by oxidative cyclisation leading to the formation of 4H-1,4-benzothiazines. The spectral investigation confirmed the synthesis of these bioactive compounds. All synthesized compounds were screened for their antimicrobial activity (antibacterial and antifungal) using agar well diffusion method. Results: The minimum inhibitory concentration values of synthesized compounds gave excellent results against bacterial as well as fungal strains (Escherichia coli [Gram negative] MTCC 2939, 58–158 μg/mL, Bacillus subtilis [Gram positive] MTCC 441, 41–124 μg/mL, Streptomyces griseus [Gram negative] MTCC 1998, 85–128 μg/mL, Fusarium oxysporum MTCC 1755, 142–151 μg/mL, Aspergillus niger MTCC 281, 59–78 μg/mL, and Rhizopus stolonifer MTCC 2591, 85–118 μg/mL). Conclusion: Synthesized substituted benzothiazines have potential to be used as a new class of antibacterial and antifungal drugs. Further biomedical research is required to make 4H-1,4-benzothiazines related compounds as potential antibacterial and antifungal drugs

Optimization and scale-up of fermentation of glucansucrase and branched glucan by Pediococcus pentosaceus CRAG3 using Taguchi methodology in bioreactor

The present investigation focuses on screening and optimization of media components to enhance glucansucrase and glucan production by Pediococcus pentosaceus CRAG3 at shake-flask and bioreactor level using Taguchi orthogonal array design. A three-level Taguchi orthogonal array layout of L27 (33) was employed, in which six variables were studied for their influence on glucansucrase and glucan production. The results showed that sucrose, K2HPO4 and Tween-80 were the most significant factors to improve glucansucrase production while the glucan production was mostly affected by sucrose, peptone and K2HPO4. The optimized medium composition for maximum glucansucrase and glucan production were: sucrose 3.5% and 5%; yeast extract 0.2% and 2.0%; beef extract 0.5% and 0.5%; peptone 3.0% and 1.0%; K2HPO4 0.2% and 0.2%, and Tween-80 1.0 and 0.1%, respectively. The optimized medium gave 10.1 U/ml and 10.2 U/ml glucansucrase activity while glucan concentrations were 56 mg/ml and 80 mg/ml in shake flask and bioreactor level, respectively which were in good agreement with predicted values (10.1 U/ml and 54.5 mg/ml). The optimized medium gave 2 fold enhancement in enzyme activity and 4 fold increase in glucan concentration as compared to non-optimized medium (4.5 U/ml and 15 mg/ml, respectively) at shake flask level

16S rRNA-Based Identification of a Glucan-Hyperproducing Weissella confusa

A gram-positive, nonmotile, irregular, short, rod-shaped new strain of Weissella confusa bacterium was isolated from fermented cabbage. The isolate was physiologically and biochemically characterised. The 16S rDNA was amplified by polymerase chain reaction (PCR). The isolate was identified as Weissella confusa (GenBank accession number: GU138518.1) based on nucleotide homology and phylogenetic analysis. The isolate produces glucansucrase when grown in sucrose-supplemented culture medium which catalyses glucan formation. This novel isolate possesses high capacity of industrial use due to its high productivity of glucan (34 mg/mL) as compared to other strains reported. The optimum temperature for glucansucrase production was 25°C. The shaking condition gave an enzyme activity of 6.1 U/mL which was 1.5 times higher than that given by static condition (4.1 U/mL). The temperature 35°C, pH 5.4, and ionic strength 10–20 mM were optimum for enzyme assay. This investigation unraveled the abundance of industrially valuable microflora of the north east India

INTERACTION OF 3-HYDROXY PYRIDINE AND SURFACTANT MICELLES: A FLUORESCENCE STUDIES

Objective: Micellar solubilization is a powerful alternative for dissolving hydrophobic compound in aqueous environment. 3-hydroxy pyridine (3- HP) derivatives are the potential endogenous photosensitizers. 3-HP derivatives show protective effect in clinical extreme condition such as hypoxia, hyperthermia, hypokinesia. Micellization of 3-HP followed by solubilization would catalyze its pharmaceutical activities which may serve better results in medicinal and analytical fields. Methods: Fluorescence and absorption spectroscopy techniques are used to monitor the micellar solubilization studies of 3-HP. Solubilization studies of 3-HP with various anionic, cationic and nonionic surfactants have been performed in aqueous medium around 23–25°C temperature. The solubilization action of the surfactant has also been determined by theoretical calculated spectral parameters such as empirical fluorescence coefficient, quantum yield, stokes, shift and molar absorption coefficient. Results: 3-HP shows fluorescence excitation peak at 315 nm and emission peak at 390 nm respectively while the absorbance of 3-HP has been found to be maximum at 305 nm. The fluorescence as well as the theoretically calculated spectral data has been used to characterize the hetero environment of the micelles in terms of their polarity, probe solubilization site and critical micelle concentration. Conclusion: This article briefly discusses the importance of surfactants in biological system model as well as the use of micelles in pharmacy as an important tool that finds numerous applications

Pročišćavanje i karakterizacija ekstracelularne dekstran saharaze iz bakterije Pediococcus pentosaceus, izolirane iz tla sjeveroistočne Indije

The extracellular dextransucrase produced from Pediococcus pentosaceus, a new isolate from the soil in Assam, India, was purified and characterized. The enzyme activity of cell-free supernatant was 3.4 U/mL and specific activity was 0.6 U/mg. The crude enzyme was purified by a single-step fractionation using polyethylene glycols of different molecular mass. The specific activity achieved was 18 U/mg with 31-fold purification by PEG 400 and 26 U/mg with 45-fold purification by PEG 1500. The molecular mass of dextransucrase determined by non-denaturing SDS-PAGE was approx. 180 kDa. The dextran formation activity of the enzyme was confirmed by activity staining. Optimum conditions for dextransucrase activity were: pH=5.4, reaction temperature 30 °C, 5 % sucrose and 20 mM sodium acetate buffer. A concentration of 1 mM MgCl2 and 6 mM CaCl2 enhanced dextransucrase activity by 5 and 150 %, respectively. The chaotropic agent urea (7 M) and chelating agent EDTA (1 mM) resulted in the residual enzyme activity of 98 and 80 %, respectively. The organic solvents such as ethanol (50 %), DMSO (90 %), acetone (50 %) and acetonitrile (20 %) decreased the dextransucrase activity by 80, 91, 94 and 80 %, respectively.U radu je pročišćena i okarakterizirana dekstran saharaza iz bakterije Pediococcus pentosaceus, izolirane iz tla u gradu Assamu, Indija. Aktivnost je enzima u supernatantu bila 3,4 U/mL, a njegova je specifična aktivnost iznosila 0,6 U/mg. Sirovi je enzim pročišćen jednostupanjskim frakcioniranjem pomoću polietilen glikola različite molekularne mase. Utvrđena je specifična aktivnost enzima od 18 (pročišćenog 31 put pomoću PEG 400), odnosno 26 U/mg (pročišćenog 45 puta pomoću PEG 1500). Molekularna je masa dekstran saharaze određena pomoću SDS-PAGE, a iznosila je otprilike 180 kDa. Aktivnost je enzima potvrđena bojanjem nastalog dekstrana s Coomasie brilijant plavom bojom. Optimalni su uvjeti za aktivnost enzima bili: pH=5,4; temperatura reakcije od 30 °C; te dodatak 5 %-tne saharoze i acetatnog pufera (20 mM). Dodatak 1 mM MgCl2 i 6 mM CaCl2 povećali su aktivnost enzima za 5, odnosno 150 %. Inaktivirajući agensi, poput uree (7 M) i EDTA (1 mM) smanjili su aktivnost enzima na 98 odnosno 80 %. Organska su otapala također smanjila aktivnost enzima, i to: 50 %-tni etanol na 80 %, 90 %-tni DMSO na 91 %, 50 %-tni aceton na 94 % i 20 %-tni acetonitril na 80 %

Dextransucrase from the mutant of Pediococcus pentosaceus (PPm) is more stable than the wild type

A comparative study on both wild type and mutant of Pediococcus pentosaceus for dextransucrase activity, its stability, dextran synthesizing activity, antibiotic sensitivity and carbohydrate utilization was performed. The wild type P. pentosaceus had specific activity of 0.58 U/mg whereas the mutant showed that of 1.0 U/mg with 72% enhancement. The antibiogram of 27 antibiotics tested against mutant showed significant differences with 9 antibiotics when compared to wild type. In carbohydrate fermentation profile, trehalose, galactose, maltose, lactose and fructose are metabolized by both the strains, but weakly in case of mutant. Stabilization of purified dextransucrase from wild type and mutant with various stabilizers was studied at 30 and 4 °C. Both enzymes were more stable at 4 °C. Among various stabilizers such as dextran (100 kDa, 10 μg/ml), glycerol (0.5%, v/v), PEG 8000 (10 μg/ml) and Tween 80 (0.5%, v/v), Tween 80 provided maximum stabilization at 4 and 30 °C. The mutant showed better stabilization than that of the wild type at both 30 and 4 °C. The loss of activity at 30 °C after 24 h in wild type and mutant in the presence of Tween 80 was only 34 and 32%, respectively, whereas the loss of activity in control of wild type and mutant was 76 and 59%, respectively. After 15 days at 4 °C, the loss of activity in control of wild type and mutant in the presence of Tween 80 was only 15 and 8%, respectively, whereas at 30 °C, the loss of activity in control of wild type and mutant was 49 and 42% respectively. Half-life of the enzyme with Tween 80 was 28.5 and 33.5 h for wild type and mutant, respectively, at 30 °C and 52.1 and 106.6 days for wild type and mutant respectively, at 4 °C

Enhancement of Cellulase Activity from a New Strain of Bacillus subtilis by Medium Optimization and Analysis with Various Cellulosic Substrates

The cellulase activity of Bacillus subtilis AS3 was enhanced by optimizing the medium composition by statistical methods. The enzyme activity with unoptimised medium with carboxymethylcellulose (CMC) was 0.07 U/mL and that was significantly enhanced by CMC, peptone, and yeast extract using Placket-Burman design. The combined effects of these nutrients on cellulase activity were studied using 22 full factorial central composite design. The optimal levels of medium components determined were CMC (1.8%), peptone (0.8%), and yeast extract (0.479%). The maximum enzyme activity predicted by the model was 0.49 U/mL which was in good agreement with the experimental value 0.43 U/mL showing 6-fold increase as compared to unoptimised medium. The enzyme showed multisubstrate specificity, showing significantly higher activity with lichenan and β-glucan and lower activity with laminarin, hydroxyethylcellulose, and steam exploded bagasse. The optimised medium with lichenan or β-glucan showed 2.5- or 2.8-fold higher activity, respectively, at same concentration as of CMC

One-pot, multicomponent synthesis of symmetrical Hantzsch 1,4-dihydropyridine derivatives using glycerol as clean and green solvent

Multi component, one pot synthesis of symmetrical 1,4-dihydropyridine derivatives from the condensation of ethyl/methyl acetoacetate, aromatic/aliphatic aldehyde and ammonium acetate has been described using glycerol, as economical, easily available and environmentally benign reagent. The targeted molecules were obtained in high purity and excellent yield without use of any additional catalyst and methodology from readily available starting materials

Physiological studies of Leuconostoc mesenteroides strain NRRL B-1149 during cultivation on glucose and fructose media

Glycosyltransferases are extracellular and cell-associated sucrase enzymes produced mainly by lactic acid bacteria Leuconostoc mesenteroides, oral Streptococcus species and also Lactobacillus species. According to the synthesized polymer (glucan or fructan) in the presence of sucrose, these enzymes are divided into two groups: glucosyltransferases (GTFs) and fructosyltransferases (FTFs). Only Streptococcus, Lactobacillus and Leuconostoc strains are known as producers of both GTFs and FTFs. The enzymes from Lactobacillus and Leuconostoc spp. are implicated in the synthesis of polymers and oligosaccharides (OS) important for human health because of their prebiotic properties and immunomodulating activity. In the present work, we studied the production of extracellular and cell-associated glycosyltransferases by Leuconostoc mesenteroides strain NRRL B-1149 during its growth on media containing glucose or fructose as a main carbon source. The enzyme activities, pH and biomass formation were measured and compared during the cultivation. We have shown that glucose and fructose have not an equal role for enzyme production. The highest extracellular activity was detected at the 4th hour during the cultivation of the strain in medium with fructose – 5.45 U/mg. When the strain was cultivated in medium with glucose, the maximum of extracellular enzyme activity was detected at the 5th hour of the cultivation but the measured activity was about 9 times lower compared to these, obtained after cultivation in fructose medium. The studied strain produced mainly extracellular glycosyltransferases in glucose or fructose medium, which were 92.4% and 97.1% of the total enzyme activity, respectively. In order to characterize the produced enzymes, cell-associated and extracellular enzymes were determined using SDS-PAGE and in situ Periodic Acid Schiff′s staining after incubation with 10% sucrose. When the investigated strain was grown in media with sucrose, glucose or fructose, several types of glycosyltransferases were detected – dextransucrase with molecular weight 180 kDa and two fructosyltransferases, corresponding to 120 kDa and 86 kDa molecular weights

Benzo[d][1,2,3]oxadithiole 2-oxide

Funding: A.G. thanks the Commissionerate of College Education, Government of Rajasthan for the generous support of a Foreign Training Program under its Teachers' Interface for Excellence Scheme.A simplified synthesis of the title compound is reported and its 1H and 13C NMR data are fully assigned including determination of H–H and C–H coupling constants. Its X-ray structure has been determined for the first time. NMR data are also presented for the oxygen analogue.Peer reviewe