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The present study describes the draft genome sequence of a novel Bacillus sp. strain SD-4 isolated from animal feed. The study aims to get a deeper insight into antimicrobial resistance and secondary metabolite biosynthetic gene clusters (BGCs) and the association between them.The strain SD-4 was preliminarily evaluated for antibacterial activities, motility, biofilm formation, and enterotoxin production using in vitro assays. The genome of strain SD-4 was sequenced using the Illumina HiSeq 2500 platform with paired-end reads. The reads were assembled and annotated using SPAdes and PGAP, respectively. The genome was further analysed using several bioinformatics tools, including TYGS, AntiSMASH, RAST, PlasmidFinder, VFDB, VirulenceFinder, CARD, PathogenFinder, MobileElement finder, IslandViewer, and CRISPRFinder.In vitro assays showed that the strain is motile, synthesises biofilm, and produces an enterotoxin and antibacterial metabolites. The genome analysis revealed that the strain SD-4 carries antimicrobial resistance genes (ARGs), virulence factors, and beneficial secondary metabolite BGCs. Further genome analysis showed interesting genome architectures containing several mobile genetic elements, including two plasmid replicons (repUS22 and rep20), five prophages, and at least four genomic islands (GIs), including one Listeria pathogenicity island LIPI-1. Moreover, the strain SD-4 is identified as a putative human pathogen.The genome of strain SD-4 harbours several BGCs coding for biologically active metabolites. It also contains antimicrobial resistance genes and is identified as a potential human pathogen. These results can be used to better comprehend antibiotic resistance in environmental bacteria that are not influenced by human intervention.

Anaerobic digestion (AD) can be used to recover nutrients from waste streams by isolating its phases. Here, we present a phase-restricted AD system (phase I only) for Phosphorus (P) release, production of Volatile Fatty Acids (VFA), ammonia (as NH4+) and biogas by digesting Chlorella vulgaris grown on agricultural waste-water using sewage sludge as inoculum. In our phase I AD system, we observed that changing the digester hydraulic retention time (HRT) altered the P, NH4+ and VFA concentrations in the effluent and biogas production. The reactor operated at 10 days HRT released maximum inorganic P (orthophosphate) in the effluent with a value of 199 ± 1 mg/L, the highest amongst considered HRTs. Maximum N in the phase-restricted AD system was observed at 14 days HRT with a final concentration of 118 ± 1 mg NH4+/L. However, the value was exceeded by a single-stage two-phase positive control batch reactor with a value of 350 ± 0.2 mg NH4+/L. The Gas Chromatography (GC) analysis indicated that VFA were present in all phase I AD reactors, with the 10 days HRT digester featuring the highest concentration at 233 mg/L. Furthermore, the phase-restricted AD approach had a positive impact on biogas generation. The 14 days HRT digester exhibited the greatest biogas production at 522 ± 1 mL in the digester’s headspace, followed by the 10 days HRT. The results of the study have established that anaerobic digesters operated at phase I with microalgae could be a promising approach for harvesting nutrients and generating biofuels in a green bioremediation system.

In this study, gold nanoparticles (AuNPs) and novel gold nanoformulations loaded with diosgenin (Dio-AuNPs) were synthesized through green approach using algal extract from Dictyosphaerium sp. strain DHM2 (LC159306) as a reducing agent. AuNPs and Dio-AuNPs synthesized were characterized through UV–vis spectroscopy, zeta potential analysis, FT-IR spectroscopy, X-ray diffraction (XRD) analysis and scanning transmission electron miroscopy. An average zeta potential value of -32.4 mV indicated that AuNPs were highly stable. Fourier transmission infrared spectroscopy (FT-IR) of AuNPs showed the presence of hydroxyl groups and carbonyl groups alongwith various other capping and stabilizing functional groups. Also, in FT-IR spectrum of Dio-AuNPs characteristic peaks of both AuNPs and diosgenin were observed. XRD analysis of AuNPs and Dio-AuNPs showed that both nanostuctures exist in the crystalline form. Scanning transmission electron microscopy (STEM) studies revealed that AuNPs and Dio-AuNPs had spherical morphology with average size range of 7.9 ± 2.4 nm and 10.3 ± 2.4 nm, respectively. Moreover, in-vitro antiproliferative activities of AuNPs and Dio-AuNPs were determined on colorectal cancer cell line HCT116 and breast cancer cell line HCC1954 using sulforhodamine B (SRB) proliferation assay. Dio-AuNPs were extremely potent with GI50 values of 1.03 ± 0.27 μg/mL and 1.69 ± 0.18 μg/mL in HCT116 and HCC1954 cell lines, respectively. AuNPs however, were almost 18 fold less potent as compared to Dio-AuNPs in both the cell lines. The current study has demonstrated biological synthesis, characterization and antiproliferative activities of gold nanoparticles and novel diosgenin loaded gold nanoformulations in colorectal and breast cancer cell lines and provided evidence that anticancer activities of both diosgenin and AuNPs can be enhanced many folds when used in conjugation.

Methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA) infections in thermally injured patients have led to intrusive disease causing mortality. Silver nanoparticles (AgNPs) employed in treatment have limitations owing to their oxidative damage and toxicity in tissues. Present study focuses on the synthesis of biocompatible AgNPs from antioxidant-rich aqueous extract of Aerva javanica. Capping of phenols on AgNPs surface was confirmed through FTIR analysis and hence spherically assembled particles of low polydispersity index exhibited Surface Plasmon Resonance at 430 nm. These assembled antibacterial AgNPs were assessed for their radical scavenging properties and cytotoxic potential on both primary (HCEC) and cancerous cell lines (Huh-7, HeLa). Potential agglomeration of intraperitoneally administered AgNPs (3–24 mg kg−1) in liver, spleen and kidney of balb/c mice was assessed through histological analysis and corresponding mortality and weight loss studies were evaluated. These AgNPs after incorporation in chitosan hydrogels were topically applied on partial thickness burn wound infections (2 × 108 CFUs of MRSA and PA) created in Balb/c mice. A significant reduction in the infection was observed with application of AgNPs incorporated hydrogels that improved the healing time.

The study describes the optimized method for silver nanoparticle (AgNPs) synthesis using Heliotropium crispum (HC) plant extract. Optimization of physicochemical parameters resulted in stable and rapidly assembled AgNPs. FTIR results suggest presence of plant phytochemicals that helped in the reduction, stabilization and capping of AgNPs. The assembled Ag nano-composites displayed the peak surface plasmon resonance (SPR) around 428 nm. The presence of uniquely assembled Ag-biomolecule composites, cap and stabilize nanoparticles in aqueous plant suspension. Spherical, uniform-shaped AgNPs with low poly-dispersion and average particle size of 42 nm and was determined through dynamic light scattering (DLS) and scanning election microscopy (SEM) which present robust interaction with microbes. The study also evaluates the antimicrobial and anti-biofilm properties of biologically synthesized AgNPs on clinical isolates of MRSA, Pseudomonas aeruginosa and Acinetobacter baumannii. Minimum inhibitory concentration (0.5 mg mL−1) of nanoparticles that presented bactericidal effect was made through inhibition assays on bacterial strains. The concentration which presented potent bactericidal response was then evaluated through growth inhibition in liquid medium for anti-biofilm studies at 2.0 mg mL−1. HC-Ag nanoparticles mediated anti-biofilm effects on Pseudomonas aeruginosa was revealed through SEM. Complete breakdown of biofilm’s extracellular polymeric substances resulted after incubation with AgNPs. Peptidoglycan cell wall destruction was also revealed on planktonic bacterial images after 24 h of incubation.

The present study was focused on the fabrication and characterization of polymeric wound dressings, composed of PVA and Starch. Graphitic carbon nitride (g-C3N4) was incorporated as a filler and Silver deposited-Titania nanoparticles (Ag@TiO2 NPs) as an antibacterial agent. The hydrogel membranes were fabricated by solution casting under ambient conditions. The prepared hydrogels were subjected to various characterizations techniques and obtained data demonstrated good compatibility among the constituents of the membranes. The antibacterial activity was investigated against Escherichia coli and Staphylococcus aureus. The maximum zone of inhibition achieved was 37.33 and 33.25 mm, respectively at the composition PVA/Starch/0.14GCN/0.7Ag@TiO2 NPs. Furthermore, swelling, moisture retention and water vapor transmission results demonstrated that hydrogels were capable of absorbing large volume of wound exudates. Porosity and oxygen permeability results have demonstrated that hydrogels membranes were breathable. Lastly, kinetics of drug release was performed by using various mathematical models where Higuchian model was found to be the best fit. Non-Fickian diffusion mechanism prevailed and a sustained and slow release of nanoparticles was observed. The complete healing was accomplished in seven days. The fabricated hydrogel membranes depicted better healing than conventional cotton gauze wound dressings. The prepared hydrogel membranes have demonstrated all the potential to be used as wound dressing for partial and full thickness excision wounds after complete biological characterization.

Extensive utilization of silver nanoparticles (AgNP) has raised concerns of their safety profile upon interaction with biological system. In past decade, various nanoparticles (NPs) with excellent antimicrobial potential have been synthesized, a majority of which have struggled with the established toxicity in biological systems. The NPs safety is still a hot debate and various strategies are being adopted to overcome this giant limitation. This paper successfully reports comparative toxicity profiles of previously synthesized antimicrobial NPs in our lab and concludes the effectiveness of biologically synthesized NPs for its safe usage in biological systems. In this study, five of our previously synthesized NPs that showed excellent antimicrobial potential were compared for their in vivo toxicity and corresponding radical scavenging activities. Based on lowest morbidity, mortality, weight loss, toxicity and agglomeration profile, best NPs with highest antimicrobial potentials were screened out and used for further biomedical applications. The previously reported NPs used in this study included Aerva javanica synthesized nanoparticles (AjNPs), Heliotropium crispium synthesized nanoparticles (HcNPs), and violacein capped nanoparticles (VNPs), these showed least toxicity upon in vivo histological analysis. AjNPs among them showed maximum safety and efficacy profile and consistently showed least production of reactive oxygen species, least mortality and morbidity rate as compared to other groups. Present study establishes that all these biologically synthesized NPs and specifically AjNPs can be efficiently employed as antimicrobial agents as they have not exhibited toxic profile and have shown least accumulation into the organs such as liver spleen and kidney.

The blood-brain barrier (BBB) poses a huge challenge and is a serious issue in deciphering the pathophysiology of central nervous system disorders. Endothelial tight junctions play an essential role in maintaining the integrity of the BBB. Post-translational modifications (PTMs) in endothelial tight junction proteins are known to cause deleterious functional impairment and possible disruptions in BBB integrity. PTMs in tight junction proteins play an important role in human immunodeficiency virus type 1 (HIV-1) entry through the BBB. Human claudin-5 is one of the highly expressed brain endothelial tight junction protein and various PTMs in claudin-5 are expected to aid HIV-1 in crossing the BBB. A precise characterization of PTMs in claudin-5 is important for understanding its role in HIV-1 brain infiltration. In this study, we have examined post-translational crosstalk between phosphorylation, O-glycosylation, palmitoylation and methylation sites in claudin-5, which could alter claudin-5's ability to maintain BBB integrity. To the best of our knowledge, this is the first report on claudin-5 protein that suggests a novel interplay between potential PTM sites. PTMs of predicted residues in claudin-5, suggested in this study, can serve as compelling targets for potential therapeutic agents against HIV-1 induced neuropathogenesis. Further site-specific experimental studies in this aspect are highly recommended.