Enhanced antibacterial activity of streptomycin against some human pathogens using green synthesized silver nanoparticles

AbstractThe development of eco-friendly technologies in nanoparticle synthesis is of utmost importance in order to expand their biological horizons. In the present study, bioreduction of AgNO3 into AgNPs using various leaf extracts of Ficus virens is explained. The resulting AgNPs were characterized by UV–vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Synthesis of AgNPs was confirmed by color change from transparent to brown with maximum absorption at 420 nm due to surface plasmon resonance of AgNPs. X-ray diffraction studies showed that the biosynthesized AgNPs were crystalline in nature, and TEM analysis showed spherical shape of the nanoparticles with size ranging from 4.98 to 29 nm. FTIR study indicates that mainly –C = O, -OH and N-H groups in leaf extracts are involved in the reduction of Ag+ ions to Ag atoms, and proteins are responsible for stabilizing the silver nanoparticles. The synthesized AgNPs showed significant antibacterial activity against Gram positive and gram negative human bacterial pathogens. The results showed that AgNPs also synergistically enhance (2.02–57.98%) the antibacterial activity of streptomycin, a common antibiotic. With this approach, AgNPs can be used as a new generation of antimicrobial agents for successful development of drug delivery

Development and use of genic molecular markers (GMMs) for construction of a transcript map of chickpea (Cicer arietinum L.)

A transcript map has been constructed by the development and integration of genic molecular markers (GMMs) including single nucleotide polymorphism (SNP), genic microsatellite or simple sequence repeat (SSR) and intron spanning region (ISR)-based markers, on an inter-specific mapping population of chickpea, the third food legume crop of the world and the first food legume crop of India. For SNP discovery through allele re-sequencing, primer pairs were designed for 688 genes/expressed sequence tags (ESTs) of chickpea and 657 genes/ESTs of closely related species of chickpea. High-quality sequence data obtained for 220 candidate genic regions on 2–20 genotypes representing 9 Cicer species provided 1,893 SNPs with an average frequency of 1/35.83 bp and 0.34 PIC (polymorphism information content) value. On an average 2.9 haplotypes were present in 220 candidate genic regions with an average haplotype diversity of 0.6326. SNP2CAPS analysis of 220 sequence alignments, as mentioned above, provided a total of 192 CAPS candidates. Experimental analysis of these 192 CAPS candidates together with 87 CAPS candidates identified earlier through in silico mining of ESTs provided scorable amplification in 173 (62.01%) cases of which predicted assays were validated in 143 (82.66%) cases (CGMM). Alignments of chickpea unigenes with Medicago truncatula genome were used to develop 121 intron spanning region (CISR) markers of which 87 yielded scorable products. In addition, optimization of 77 EST-derived SSR (ICCeM) markers provided 51 scorable markers. Screening of easily assayable 281 markers including 143 CGMMs, 87 CISRs and 51 ICCeMs on 5 parental genotypes of three mapping populations identified 104 polymorphic markers including 90 markers on the inter-specific mapping population. Sixty-two of these GMMs together with 218 earlier published markers (including 64 GMM loci) and 20 other unpublished markers could be integrated into this genetic map. A genetic map developed here, therefore, has a total of 300 loci including 126 GMM loci and spans 766.56 cM, with an average inter-marker distance of 2.55 cM. In summary, this is the first report on the development of large-scale genic markers including development of easily assayable markers and a transcript map of chickpea. These resources should be useful not only for genome analysis and genetics and breeding applications of chickpea, but also for comparative legume genomics

Biosynthesis of Palladium Nanoparticles Using Delonix regia Leaf Extract and Its Catalytic Activity for Nitro-aromatics Hydrogenation

This work presents the biosynthesis of palladium nanoparticles (Pd-NPs) using Delonix regia (D. regia) leaf extract, and their catalytic activity was evaluated for 2-nitrophenol (2-NP) and 2-nitroaniline (2-NA) hydrogenation reactions. The appearance of a broad continuous absorption spectrum in the visible–ultraviolet region in UV–visible spectra confirmed the synthesis of Pd-NPs. The crystalline structure of Pd-NPs (with size range of 2–4 nm) was confirmed by X-ray diffraction and transmission electron microscopy analysis, respectively. The appearance of an optical absorption peak at 2.80 keV in energy dispersive spectra further confirmed the presence of Pd-NPs. Fourier transform infrared analysis suggested the role of water-soluble polyols present in the D. regia leaf extract in mediating the synthesis of Pd-NPs. Moreover, the catalytic activity of Pd-NPs for hydrogenation reactions was studied by UV–visible spectroscopy. Pd-NPs showed catalytic activity through electron relay effect. The hydrogenation reactions followed pseudo-first-order kinetics with respect to the substrates

Noble Metal Nanoparticles: Plant-Mediated Synthesis, Mechanistic Aspects of Synthesis, and Applications

In recent years, the progress of efficient green chemistry approaches for the fabrication of commercially viable noble metallic nanoparticles has become a major focus of researchers. The present review has focused on the various plant-mediated nanoparticle fabrication approaches, with brief discussions on the categories of various plant-mediated synthesis approaches and mechanistic aspects of plant-mediated nanoparticle synthesis. The review also focused on the commercial applications of plant-mediated noble metal nanoparticles. Significant remarks on the limitations of plant-mediated fabrication approaches with prospective future direction are also examined