Nanometal surface energy transfer (NSET) from biologically active heterocyclic ligands to silver nanoparticles induces enhanced antimicrobial activity against gram-positive bacteria.

Herein we report the formation of a nanometal surface energy transfer (NSET) pair between a donor biologically active heterocyclic luminescent ligand such as 3-(1,3-Dioxoisoindolin-2-yl)-N, N-dimethylpropan-1-ammonium perchlorate (S4PNL; λem-408 nm) and an acceptor silver nanoparticle (Ag NP; λabs-406 nm). When the S4PNL ligand interacts with Ag NPs, the quenching in their luminescence intensity at 408 nm is noticed, with a Stern-Volmer constant of 0.8 × 104 M-1. The present donor-acceptor pair displays a binding constant of 2.8 × 104 M-1 and binding sites of 1.12. The current work shows the energy transfer from a molecular dipole (S4PNL) to a nanometal surface (Ag NP) and thus follows the nanometal surface energy transfer (NSET) ruler with an energy transfer efficiency of 80.0%, 50% energy transfer efficiency distance (d0) of 4.9 nm, donor-acceptor distance of 3.4 nm. The alteration in the zeta potential value of S4PNL upon interaction with AgNP clearly demonstrates the strong electrostatic interaction between donor and acceptor. Importantly, the current NSET pair shows enhanced antimicrobial activity against gram-positive bacteria such as Bacillus cereus (B. cereus) in comparison to their parent components i.e. S4PNL ligand and Ag NP. The NSET pair shows maximum inhibition against B. cereus (9202.21 ± 463.26 CFU/ml.) at 10% while minimum inhibition is observed at 0.01% of it (39,887.19 ± 242.67 CFU/ml.).

Insights into the Formations of Host-Guest Complexes Based on the Benzimidazolium Based Ionic Liquids-ß-Cyclodextrin Systems.

Inclusion complexation is one of the best strategies for developing a controlled release of a toxic drug without unexpected side effects from the very beginning of the administration to the target site. In this study, three benzimidazolium based ionic liquids (ILs) having bromide anion and cation bearing long alkyl chains, hexyl- ([C6CFBim]Br), octyl- ([C8CFBim]Br), and decyl- ([C10CFBim]Br) were designed and synthesized as antibacterial drugs. Inclusion complexes (ICs) of studied ILs have been prepared by the combination of ß-cyclodextrin (ß-CD), considering these conjugations should enhance the benignity of ILs and make them potential candidates for the controlled drug release. Characterizations and structural analysis of studied ICs have been performed by 1H NMR, 2D-ROESY NMR, FT-IR, HRMS, TGA, DSC, surface tension, ionic conductivity, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). Further, the morphology of the ICs has been analyzed by SEM and TEM. Furthermore, neat ILs and ICs have been treated against Escherichia coli and Bacillus subtilis to investigate their antibacterial activity, which confirms the prevention of bacterium growth and the shrinkage of the bacterial cell wall. The findings of this work provide the proof of concept that studied benzimidazolium based ILs-ß-CD host-guest complexes should act as a potential candidate in controlled drug delivery and other biomedical applications.

Draft Genome Sequences of Two Boron-Tolerant, Arsenic-Resistant, Gram-Positive Bacterial Strains, Lysinibacillus sp. OL1 and Enterococcus sp. OL5, Isolated from Boron-Fortified Cauliflower-Growing Field Soils of Northern West Bengal, India.

Two novel boron-tolerant, arsenic-resistant, Gram-positive bacterial strains, Lysinibacillus sp. OL1 and Enterococcus sp. OL5, were isolated from boron fertilizer-amended cauliflower plantation field soils in India. Here, we report the draft genome sequences of OL1 (4.87 Mb) and OL5 (3.93 Mb) to explore the intricacies of boron tolerance in bacteria.

Pradoshia eiseniae gen. nov., sp. nov., a spore-forming member of the family Bacillaceae capable of assimilating 3-nitropropionic acid, isolated from the anterior gut of the earthworm Eisenia fetida.

A Gram-stain-positive, spore-forming bacterium, EAG3T, capable of growing on 3-nitropropionic acid as the sole source of carbon, nitrogen and energy, was isolated from the anterior gut of an earthworm (Eisenia fetida) reared at the Centre of Floriculture and Agribusiness Management of the University of North Bengal at Siliguri (26.7072° N, 88.3558° E), West Bengal, India. The DNA G+C content of strain EAG3T was 42.5 mol%. Strain EAG3T contained MK-7 and MK-8 as predominant menaquinones. The predominant polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were 13-methyltetradecanoic acid, (9Z)-9-hexadecen-1-ol, 12-methyltetradecanoic acid and 14-methylpentadecanoic acid. The draft genome of strain EAG3T, distributed in 57 contigs, was found to be 3.8 Mb. A total of 3811 potential coding sequences or genes were predicted, including 3672 protein-coding and 108 RNA-coding ones together with 31 pseudogenes. One hundred and thirty-five genes encoded hypothetical proteins with no meaningful homologies with known proteins. The EAG3T genome encompassed two nitronate monooxygenase and one methylmalonate-semialdehyde dehydrogenase (CoA acylating) homologues. 16S rRNA gene sequence-based phylogeny revealed that the closest relative of strain EAG3T was Bacillus methanolicus NCIMB 13113T (95.7 % similarity). Phylogenetic, physiological and biochemical characteristics differentiated strain EAG3T from B. methanolicus, as well as from the other close taxonomic relatives Planococcus rifietoensis M8T, Bhargavaea cecembensis DSE10T, Planomicrobium flavidum ISL-41Tand Fermentibacilluspolygoni IEB3T, with which strain EAG3T had 93.3-94.2 % 16S rRNA gene sequence similarities. The new isolate, therefore, was considered as representing a novel genus of family Bacillaceae, for which the name Pradoshia eiseniae gen. nov., sp. nov. is proposed, with EAG3T (=LMG 30312T=JCM 32460T) as the type strain.

Chryseomicrobium excrementi sp. nov., a Gram-stain-positive rod-shaped bacterium isolated from an earthworm (Eisenia fetida) cast.

A Gram-stain-positive, rod-shaped, slightly halotolerant, nitrate-reducing bacterial strain, designated ET03T, was isolated from the cast of an earthworm (Eisenia fetida) reared at the Centre of Floriculture and Agribusiness Management, University of North Bengal at Siliguri, West Bengal, India. On the basis of 16S rRNA gene sequence phylogeny, the closest relative of strain ET03T was Chryseomicrobium palamuruense PU1T (99.1 % similarity). The DNA G+C content of strain ET03T was 42.9 mol%. Strain ET03T contained menaquinone-8 as the most predominant menaquinone and phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and phosphatidylglycerol as the main polar lipids. The diagnostic diamino acid was meso-diaminopimelic acid. Major cellular fatty acids were iso-C15 : 0, C16 : 1ω7c alcohol and iso-C16 : 0. Other biochemical and physiological analyses supported genotypic and phenotypic differentiation of the strain ET03T from its nearest taxonomic neighbours: Chryseomicrobium palamuruense,Chryseomicrobium amylolyticum, Chryseomicrobium imtechense, Chryseomicrobium aureum and Chryseomicrobium deserti. The draft genome of strain ET03T consisted of 2.64 Mb distributed in 14 scaffolds (N50 894072). A total of 2728 genes were predicted and, of those, 2664 were protein-coding genes including genes involved in the degradation of polychlorinated biphenyl and several aromatic compounds. The isolate, therefore, represents a novel species, for which the name Chryseomicrobium excrementi sp. nov. is proposed. The type strain is ET03T (=KCTC 33943T=LMG 30119T=JCM 32415T).

Draft Genome Sequence of a Novel Bacterium, Pseudomonas sp. Strain MR 02, Capable of Pyomelanin Production, Isolated from the Mahananda River at Siliguri, West Bengal, India.

The draft genome sequence of a novel strain, Pseudomonas sp. MR 02, a pyomelanin-producing bacterium isolated from the Mahananda River at Siliguri, West Bengal, India, is reported here. This strain has a genome size of 5.94 Mb, with an overall G+C content of 62.6%. The draft genome reports 5,799 genes (mean gene length, 923 bp), among which 5,503 are protein-coding genes, including the genes required for the catabolism of tyrosine or phenylalanine for the characteristic production of homogentisic acid (HGA). Excess HGA, on excretion, auto-oxidizes and polymerizes to form pyomelanin.

Lignin-graft-Polyoxazoline Conjugated Triazole a Novel Anti-Infective Ointment to Control Persistent Inflammation.

Lignin, one of the most abundant renewable feedstock, is used to develop a biocompatible hydrogel as anti-infective ointment. A hydrophilic polyoxazoline chain is grafted through ring opening polymerization, possess homogeneous spherical nanoparticles of 10-15 nm. The copolymer was covalently modified with triazole moiety to fortify the antimicrobial and antibiofilm activities. The hydrogel was capable of down regulating the expression level of IL-1ß in LPS induced macrophage cells, and to cause significant reduction of iNOS production. It supported cellular anti-inflammatory activity which was confirmed with luciferase assay, western blot, and NF-κB analysis. This novel lignin-based hydrogel tested in-vivo has shown the abilities to prevent infection of burn wound, aid healing, and an anti-inflammatory dressing material. The hydrogel reported here provides a new material platform to introduce a cost-effective and efficient ointment option after undertaking further work to look at its use in the area of clinical practice.