Antioxidant attributes of tea in North Bengal, India: Relation with its principal constituents and properties of soil

This study was performed in 18 tea gardens in North Bengal, India, from 2012 to 2017. The data were pooled to investigate the relationship with soil physico-chemical properties, phyto-constituents, antioxidant attributes and age of the tea bushes and principal component analysis (PCA). PCA and dendro-hit maps were also performed with each region. The 28 principal components were chosen based on their eigen values, explaining the total data variance for tea in Dooars, Terai and Darjeeling hill. In almost all cases, composite soil physico-chemical attributes were heavily loaded on the second principal component and clustered, as visual evidenced by the dendro-hit map. Different attributes were significantly correlated each other in case of Terai i.e. (value of “r’’ at P<0.01 level) clay fraction (0.778), electrical conductivity (0.618), N (0.777), S (0.748), P (0.514 ppm), flavour index (0.918), total polyphenol (0.687) DPPH (0.794), nitric oxide (0.913), anti-lipid peroxidation (0.717) and metal chelating (0.665). In Dooars region, attributes were significantly correlated with silt (0.718), pH (0.875), P (0.615 ), chloride (0.858), TP (0.776), flavonol (0.923), quinone (0.666), tannins (0.865), DPPH (0.536), superoxide (0.576), ABTS (0.520) and MC (0.777) and in the case of Darjeeling hills, attributes were highly correlated with clay (0.812), sand (0.818), silt fraction (0.974), K (0.932), S (0.999), MC of soil (0.671), TP (0.853), tannins (0.912), DPPH (0.624), ABTS (0.661) and MC (0.633) repectively

ALUMINA CATALYST: SYNTHESIS OF NOVEL QUINAZOLINE DERIVATIVES AND THEIR SOLUBILITY INCREASES THROUGH INCLUSION WITH β-CYCLODEXTRIN

Objective: To synthesis a novel methodology of bioactive quinazoline derivatives under greener process to an excellent yields and increases their solubility via inclusion with β-cyclodextrin (CD). Methods: Derivatives of quinazoline compounds were prepared by the mixture of 3-amino-2-phenylquinazolin-4(3H)-one, derived from 2-phenyl-4H-benzo[1,3]oxazin-4-one by refluxing with hydrazine, substituted aromatic aldehyde and alumina intimately in an agate mortar and pestle under solvent-free condition. Using various techniques for preparing inclusion complexes, kneaded method is the best method for encapsulation in host-guest complex chemistry. All compounds including inclusion complexes were characterised by spectral methods. Results: Synthesized a series of novel quinazoline compounds under a very easier greener process with a commercially available reagent. However, their low bioavailability, due to low absorption and solubility, can limit their potential applications. CD was used to resolve this solubility problem. CD can easily accommodated the guest molecules to encapsulate inside its cavity due to interior the hydrophobic nature with a hydrophilic exterior part to form thermodynamically more stable molecular microcapsules, commonly name as host-guest complexes or inclusion complexes. In this sense, CD was utilized to enhance not only the solubility and bioavailability of these quinazoline compounds but also their antibacterial capacity. The formation of inclusion complex was thus confirmed by ultraviolet-visible spectroscopy (UV-VIS), Fourier Transform Infrared Spectrometry (FT-IR), differential scanning calorimetry (DSC) and solubility study technique. Conclusion: Here we have successfully unfolded an eco-friendly methodology for the synthesis of derivatives of quinazoline and increased their solubility via host-guest inclusion technique. From the spectral analysis, it was concluded that the quinazoline compound is fully encapsulated inside the cavity of the CD

Antibacterial Activity of Some 3-(Arylideneamino)-2-phenylquinazoline-4(3H)-ones: Synthesis and Preliminary QSAR Studies

Synthesis of ten 3-(arylideneamino)-2-phenylquinazoline-4(3H)-ones is reported. All the compounds contained a common phenyl group at the 2-position, while the substituents on the arylideneamino group were varied. The compounds were investigated for their antimicrobial activity against both Gram-positive (Staphylococcus aureus 6571 and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli K12 and Shigella dysenteriae 6) using a turbidometric assay method. It was found that the incorporation of the 3-arylideneamino substituent enhanced the anti-bacterial activity of the quinazolone system. The preliminary QSAR studies were done using some computer derived property descriptors, calculated values of partition coefficients as well as usual Hammett’s sigma constants and the substituent’s molar refractivity

An Escherichia coli strain, PGB01, isolated from feral pigeon Faeces, thermally fit to survive in pigeon, shows high level resistance to trimethoprim.

In this study, of the hundred Escherichia coli strains isolated from feral Pigeon faeces, eighty five strains were resistant to one or more antibiotics and fifteen sensitive to all the antibiotics tested. The only strain (among all antibiotic-resistant E. coli isolates) that possessed class 1 integron was PGB01. The dihydrofolate reductase gene of the said integron was cloned, sequenced and expressed in E. coli JM109. Since PGB01 was native to pigeon's gut, we have compared the growth of PGB01 at two different temperatures, 42°C (normal body temperature of pigeon) and 37°C (optimal growth temperature of E. coli; also the human body temperature), with E. coli K12. It was found that PGB01 grew better than the laboratory strain E. coli K12 at 37°C as well as at 42°C. In the thermal fitness assay, it was observed that the cells of PGB01 were better adapted to 42°C, resembling the average body temperature of pigeon. The strain PGB01 also sustained more microwave mediated thermal stress than E. coli K12 cells. The NMR spectra of the whole cells of PGB01 varied from E. coli K12 in several spectral peaks relating some metabolic adaptation to thermotolerance. On elevating the growth temperature from 37°C to 42°C, susceptibility to kanamycin (both strains were sensitive to it) of E. coli K12 was increased, but in case of PGB01 no change in susceptibility took place. We have also attempted to reveal the basis of trimethoprim resistance phenotype conferred by the dfrA7 gene homologue of PGB01. Molecular Dynamics (MD) simulation study of docked complexes, PGB01-DfrA7 and E. coli TMP-sensitive-Dfr with trimethoprim (TMP) showed loss of some of the hydrogen and hydrophobic interaction between TMP and mutated residues in PGB01-DfrA7-TMP complex compared to TMP-sensitive-Dfr-TMP complex. This loss of interaction entails decrease in affinity of TMP for PGB01-DfrA7 compared to TMP-sensitive-Dfr

16S rRNA gene sequence analyses of the metagenome derived from waters of river Mahananda at Siliguri: An approach to understand bacterial diversity

80-87Bacterial community of the sub-Himalayan river Mahananda at Siliguri, India was characterized by amplification and sequencing of 16S rRNA genes. Analysis of almost complete 115 sequences revealed a total of 43 operational taxonomic units (OTUs). Statistical analysis revealed that coverage of the clone library was 81.73%. All sequences had >85% similarity to 16S rRNA gene sequences retrieved from the DNA databases. The sequences largely constituted of the class Proteobacteria (10.43% Alpha subdivision, 50.43% Beta subdivision, 9.56% Gamma subdivision & 14.7% Epsilon subdivision), phylum Bacteroidetes (8.69%) and Firmicutes (5.21%), besides single representative belonging to the candidate division OP 11 (0.86%). 31.3% of the total clones showed high similarity to uncultured bacteria, suggesting the usefulness of this technique in uncovering microbial diversity in river water. Abundance of Comamonads (61.76%) among Betaproteobacteria indicated transition to eutrophic state, confirming borderline healthy state of Mahananda River at Siliguri. The most dominant genus of this clone library was Arcobacter, whose presence in environmental waters being associated with fecal pollution has been confirmed

Hydrogen bonding between ligand and protein active site residues.

<p>Dash line shows hydrogen bond between, trimethoprim (magenta) and protein active site residues (green), A) TMP-sensitive-Dfr-TMP complex, B) PGB01-DfrA7-TMP complex.</p

Effect of microwave radiation on cell viability.

<p>A. Thermal effect of microwave radiation: Temperature of LB vs. time of exposure; B. Viability of cells vs. time of microwave exposure.</p

Diagram of amplified class 1 integron.

<p>Schematic representation of class 1 integron amplicon of the strain PGB01 amplified with the Int₂F-3′CS primer pair. Numbers correspond to sequence positions in EMBL Ac. No. FN563072.</p

Superimposition of protein active site residues.

<p>Superimposed side chain representation of protein active site residues of TMP-sensitive-Dfr (magenta) and PGB01-DfrA7 (orange).</p