Optimization of cryopreservation of pathogenic microbial strains

The preservation of pathogenic microbial strains is of great significance for basic research in microbiology and utilization of microbial resources.Appropriate preservation methods can maintain high survival rate and genetic stability of pathogenic microbial strains for a long time.This study summarizes the current status of preservation of strains,discusses the limitations and damaging factors of cryopreservation and prospects for optimization,and explores the mechanism of cryopreservation of strains.Our main objective is to provide a reference for the long-term effective preservation of microbial resources and guarantee of national biosafety.

Biosafety laboratory risk assessment

Biosafety laboratory risk assessment is a dynamic and systematic work.The scope of the assessment involves evaluation of pathogenic microbial hazards,experimental activities,facilities and equipment,personnel,experimental methods,etc.The four-level evaluation method for pathogenic microorganisms is used for hazard assessment.The aerosol exposure risk is the most common in experimental activities.Facilities and equipment are the basis for the safe operation of biosafety laboratories.Laboratory biosafety risk assessments should be conducted regularly to ensure the safe operation of the laboratory.

The negative effects of soil microorganisms on plant growth only extend to the first weeks

Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three stages:early,mid and late growth.We performed two growth experiments with Jacobaea vulgaris,which lasted 49 and 63 days in sterilized soil or live soil.In a third experiment,we examined the effect of the timing of soil inoculation prior to planting on the relative growth rate of J.vulgaris with four different timing treatments.In all experiments,differences in biomass of plants grown in sterilized soil and live soil increased throughout the experiment.Also,the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks.In the third experiment,plant biomass decreased with increasing time between inoculation and planting.Overall,our results showed that plants of J.vulgaris grew less well in live soil than in sterilized soil.The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks.

Chlorine as an integrated approach for environmental health and hygiene:A case study on evaluation of the performance of waste stabilization ponds located at 11 governorates in Egypt

The current study summarizes the current status of wastewater stabilization ponds(WSPs)treatment plants that have already been built in 11 governorates throughout Egypt.Moreover,this study aims to determine the most appropriate chlorine dose for waste stabilization ponds(WSPs)effluents to ensure the treated effluents are suitable for reuse in unrestricted irrigation and to comply with the current legislation on direct discharge onto water bodies.According to the findings,the chlorine doses used as a disinfectant in the treated effluents of the majority of WSP treatment plants ranged from 3 to 13 mg/L.Meanwhile,two of the WSPs treatment plants effluents,the Qus WSPs treatment plant in Qena governorate and the Al Zarabii WSPs treatment plant in Asyut governorate used high chlorine doses reached to 17 and 19 mg/L,respectively.This is due to the fact that both the Qus and Al Zarabii WSPs treatment plants have a high organic load,which necessitated the use of more chlorine to achieve the optimum chlorine dose at 13 mg/L for Qus and 11mg/L for Al Zarabii.The findings demonstrated that chlorine has a powerful effect in completely removing bacteria.Furthermore,in most chlorine-treated wastewater final effluents,as the chlorine doses increased,the chlorophyll-a reading decreased.The amount of trihalomethanes(THMs)produced as disinfectant byproduct was measured.The results proved that the water can be used in unrestricted irrigation,and after adding chlorine,it can be dumped on water bodies without health risks.

Plant biotic interactions

Plants are constantly under attack by pathogens,pests,and parasites,resulting in severe consequences on global food production and human health.While pathogens and pests find their ways to invade and communicate with their hosts,plants have evolved sophisticated immune systems to fight infections.