Approximately all sequenced archaeal and half of eubacterial genomes have some sort of adaptive immune system, which enables them to target and cleave invading foreign genetic elements by an RNAi-like pathway. CRISPR–Cas (clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins) systems consist of the CRISPR loci with multiple copies of a short repeat sequence separated by variable sequences with similar size that are derived from invaders and cas genes encode proteins involved in RNA binding, endo- and exo-nucleases, helicases, and polymerases activities. There are three main types (I, II and III) of CRISPR/Cas systems. All systems function in three distinct stages: (1) adaptation, (2) crRNA biogenesis, and (3) interference. This review focuses on the features and mechanisms of the CRISPR-Cas systems and current finding about them.

Introduction: Recent increases in microbial resistance to multiple antibiotics have led to the emergence of more economical methods for producing nanoparticles with physical, chemical effects and limited resistance. The aim of this research was to study zinc oxide (ZnO) nanoparticles synthesis and antibacterial properties against some gram-negative and gram-positive bacteria. Material and Methods: In this study, ZnO nanoparticle was synthesized using ultrasonic method and bioassayed on 10 human pathogenic bacteria by agar well diffusion method. In addition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined as well. Antibiotic resistance pattern of bacteria was determined to 9 antibiotics: gentamicin, ampicillin, nalidixic acid, amoxicillin, amikacin, ciprofloxacin, co-trimoxazole, norfloxacin and cephalexin by disc diffusion assay. Results: The nanoparticles were synthesized with suitable morphology and distribution. All gram-positive and gram-negative bacteria were inhibited at the low concentration of ZnO nanoparticles most bacteria had resistance to antibiotics. Conclusions: The findings suggest that the ZnO nanoparticles have potential applications as antibacterial compounds and their mechanism of action is dependent upon composition and surface modifications.

Background and purpose: The study was launched to use zinc finger nuclease (ZFN) technology to disrupt the cholera toxin gene (ctxA) for inhibiting CT toxin production in Vibrio cholera (V. cholera). Experimental approach: An engineered ZFN was designed to target the catalytic site of the ctxA gene. The coding sequence of ZFN was cloned to pKD46, pTZ57R T/A vector, and E2-crimson plasmid and transformed to Escherichia coli (E. coli) Top10 and V. cholera. The efficiency of ZFN was evaluated by colony counting. Findings/Results: No expression was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting in transformed E. coli. The ctxA gene sequencing did not show any mutation. Polymerase chain reaction on pKD46-ZFN plasmid had negative results. Transformation of E. coli Top10 with T/A vectors containing whole ZFN sequence led to 7 colonies all of which contained bacteria with self-ligated vector. Transformation with left array ZFN led to 24 colonies of which 6 contained bacteria with self-ligated vector and 18 of them contained bacteria with vector/left array. Transformation of V. cholera with E2-crimson vectors containing whole ZFN did not produce any colonies. Transformation with left array vectors led to 17 colonies containing bacteria with vector/left array. Left array protein band was captured using western blot assay. Conclusions and implications: ZFN might have off target on bacterial genome causing lethal double-strand DNA break due to lack of non-homologous end joining (NHEJ) mechanism. It is recommended to develop ZFNs against bacterial genes, engineered packaging host with NHEJ repair system is essential.

The consumption of microorganisms proposed to connect metal nanoparticles is in the glow of advertising of modern nanotechnology. Performs as a biodegradable and joyful loom, designed for the assembly of nanoparticles, appreciations to which it is necessary for squat, ecological compatibility, reduced production expenses, the scalability, and stabilization of nanoparticles are compared in bodily and chemical combination. Biologically connected metal nanoparticles are almost all well-organized miniaturized, usable resources constructed and designed to perform precise functions in the company of enormous prospects. Microbes include this amazing competence towards appearance, such delicate nanostructures. This studies the exercise information of organic combination of zinc oxide and lead nitrate nanoparticles as a result of microbes. Microorganisms engage in recreation directly or indirectly in more than a few biological behaviors because metals present in soil are in constant relation to biological components. In the current study, the reported microbiological combination of nanomaterials uses organic ingredients, primarily prokaryotes and eukaryotes, such as bacteria and fungi (Escherichia coli and Aspergillusniger). Bacterial and fungal cell buildup is questioned among two different chemical salts (ZnO and Pb (NO3)2) together with metal nanoparticles should be effectively synthesized.