Detection of bla TEM β-lactamase genes from clinical isolates of Pseudomonas aeruginosa in Chennai, India

ABSTRACT Existence of metallo-β-lactamases (MBLs) genes plays an important role in spreading β-lactam antibiotic resistance in the producing strains of these enzymes. The resistance of gram-negetive bacteria, such as Pseudomonas aeruginosa, to different antimicrobial agent, especially β-lactam and carbapenem, has been reported with increasing frequency worldwide. The aim of this study was to investigate the prevalence of bla TEM gene encoding metallo-β-lactamases among a collection of Pseudomonas aeruginosa strains isolated from patients at different hospitals and health centers in Chennai, India through duplex PCR method. Susceptibility of 65 P. aeruginosa to 4 different antibiotics was determined using disc diffusion method. Isolates showing resistance to cefotaxime, ceftizoxime, amikacin and imipenem were subjected to micro broth dilution assay to determine their MIC values. Isolates containing bla TEM were analyzed by Agarose Gel Electrophoresis (AGE). No other MBL genes were detected in this study. Six patterns were found for isolates containing bla TEM gene by AGE. The bla TEM was the main gene encoding MBLs among the isolates of P. aeruginosa in our study

ANTIOXIDANT AND ANTICANCER POTENTIALS OF BIOFABRICATED SILVER NANOPARTICLES

  Objective: The objective of this study is to explore a rapid, bio-inspired approach to synthesize silver nanoparticles (AgNPs) using aqueous Nardostachys jatamansi leaf extract and evaluate its antioxidant and cytotoxic activities on human colon carcinoma (HCT-116) cell lines.Methods: The biosynthesized nanoparticles were analyzed using ultraviolet-visible spectrophotometer, scanning electron microscope (SEM), energy dispersive X-ray, X-ray diffractometer (XRD), and Fourier transform infrared spectroscopy. Free radical scavenging and cytotoxic studies were carried out at different concentrations of AgNPs (20-100 μg/mL) using antioxidant 2,2-diphenyl-1-picrylhydrazil (DPPH) and mitochondrial function assay methods.Results: Surface plasmon resonance spectrum at 434 nm confirmed the formation of AgNPs. SEM images show biosynthesized AgNPs are mostly spherical shaped within the range of 30.0-58.7 nm. XRD analysis reveals the crystallographic face-centered cubic structure of the AgNPs. Thus, synthesized metal nanoparticles were tested for antioxidant activity by DPPH assay, and anticancer activity was validated by lactate dehydrogenase leakage assay. Significant antioxidant property was observed as compared to standard L-ascorbic acid. Further, AgNPs showed a linear dose-response relationship against HCT-116 cell lines with increasing concentration of AgNPs. At a concentration of 20 μg/mL, AgNPs were able to inhibit the cell line's growth by less than 9.8 ± 0.7%, whereas 100 μg/mL of AgNPs significantly inhibited the cell line's growth greater than 90.4 ± 0.25%.Conclusion: The synthesized AgNPs were found to be highly stable and had significant antioxidant and anticancer activity against HCT-116 cell lines. It has wide applications in the biomedical field and can be produced with eco-friendly, rapid scale-up, and easy downstream processing

Exploration of Wedelia chinensis leaf-assisted silver nanoparticles for antioxidant, antibacterial and in vitro cytotoxic applications

Green synthetic route of silver nanoparticles (AgNPs) has already been proved to be an advantageous over other physico-chemical approaches due to its simplicity, cost effectiveness, ecofriendly and nontoxicity. In this finding, aqueous Wedelia chinensis leaf extract (WLE) mediated synthesis of AgNPs was approached. Surface plasmon resonance (SPR) band at 408 nm preliminary indicated the formation of AgNPs, while TEM and XRD characterization confirmed the formation of spherically shaped and crystalline AgNPs with an average size of 31.68 nm, respectively. The plausible biomolecules in the aqueous leaf extract responsible for the reduction and stabilization of AgNPs were identified by FTIR analysis and found to be polyphenolic groups in flavonoid. Further, synthesized AgNPs was explored for different biological applications. Biosynthesized AgNPs showed significant free radical scavenging activity as compared to Wedelia leaf extract and antibacterial activity against clinically isolated test pathogens where Gram-negative bacteria were found more susceptible to AgNPs than Gram-positive one. In addition, in vitro cytotoxic response was also evaluated on hepatocellular carcinoma Hep G2 cell lines and showed a dose-dependent cytotoxic response with an IC50 value of 25 μg/mL. Keywords: Wedelia chinensis, AgNPs, Antioxidant, Antibacterial, Cytotoxicit

EXTRACTION AND CHARACTERIZATION OF GELATIN: A FUNCTIONAL BIOPOLYMER

Objective: Gelatin is widely used biopolymer in various industries due to its excellent biocompatibility, biodegradability properties. In the present study, gelatin was extracted from fish wastes, as an alternative source.Methods: This biopolymer was extracted from the scales of freshwater fish, Labeo rohita. After extraction, the proximate analysis and physico-chemical analysis of the fish scale gelatin were carried out. This functional polymer was also characterized using different analytical methods, such as UV-vis spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) for the evaluation of crystalline and surface morphology, and fourier transform infrared spectroscopy (FTIR) for structural determination.Results: The scales of L. rohita yield 24% (dry weight basis) of gelatin, indicating this fish species as potential source of gelatin. The proximate analysis determined was low moisture content (4.2%), ash (1.4%) and high protein (90%) content. The result of the study confirms the effectiveness of extraction method used.Conclusion: The fish scales of L. rohita are found to be a sustainable and renewable source of gelatin with desirable functionalities and it is the best alternative for mammalian gelatin in food and other industries