With increasing uses of DNA fingerprinting, restriction fragment length polymorphism (RFLP) analysis, and PCR-based techniques like random-amplified polymorphic DNA (RAPD) in genome research, the difficulty of isolating high molecular weight DNA, especially from plants, fungi, and other organisms with cell walls, becomes a main obstacle. Quite a few protocols have been reported. But almost all of them include freezing with nitrogen and homogenizing with mortal and pestle or a mechanical homogenizer (1, 2). Some of them involve phenol-chloroform extraction (3), while others require gradient sedimentation with cesium chloride or precipitation with CTAB (4). All these treatments are time-consuming and tedious. Here, with the use of benzyl chloride, a simple, fast procedure is developed. Benzyl chloride can destroy cell walls of plants, fungi and bacteria E N
In this study, the conditions and mechanism of antibacterial activity of hydrophilic polymer coated silver nanoparticles (AgNPs) against E. coli O157:H7 (CMCC44828) as model pathogen was studied. The AgNPs were coated with amphiphilic polymer that introduced carboxyl groups on the surface to make it water-soluble. The AgNPs were exposed to various treatment conditions of pH and temperature before these were combined with the E. coli. The mechanism of the antibacterial activity was studied through the formation of reactive oxygen species (ROS) that was later suppressed with antioxidant to establish correlation with the AgNPs antimicrobial activity. Studies were carried out at both anaerobic and aerobic conditions. The results indicated that 5 mg/L AgNPs inhibited ~50% of the growth of 10(6) colony forming units per milliliter (cfu/mL) E. coli cells in liquid Luria-Bertani (LB) medium. This dose-dependent antimicrobial activity was higher at increased temperature (37°C) but was lower when the AgNPs were treated with acid at pH 2 before exposure to the bacteria. It was also established that the conditions of higher antimicrobial effect generated more ROS that was dependent on the presence of oxygen. The antibacterial activity was suppressed in the presence of an antioxidant.
Infections with bacterial or fungal biofilms have emerged as a major public heath concern because biofilm-growing cells are highly resistant to both antibiotics and host immune defenses. This review focuses on the progress in understanding the mechanisms of biofilm-specific antimicrobial resistance and in developing innovative therapeutic measures based on novel antibiofilm agents.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.