Protein S-nitrosylation regulates the energy metabolism of early postmortem pork using the in vitro model

This research aimed to investigate the regulation of energy metabolism by protein S-nitrosylation utilizing the in vitro muscle glycolysis model.Longissimus thoracis(LT)muscles homogenates were treated with nitric oxide donor NOR-3((±)-(E)-4-Ethyl-2-(E)-hydroxyimino-5-nitro-3-hexenamide)and control(0.1 M K_(2)HPO_(4))under different pH conditions(6.5,6.0 and 5.5)in vitro buffer system for 24 h,respectively.Results indicated that the NOR-3 treatment group had a significantly higher pH decline rate than the control group and resulted in a higher lactate accumulation and glycogen degradation at 24 h compared with the control group(p<0.05).Moreover,NOR-3 treatment significantly increased the activities along with S-nitrosylation levels of lactate dehydrogenase and glycogen phosphorylase at pH 6.5 in a concentration-dependent manner(p<0.05).In addition,low pH could weaken the NOR-3 treatment effect and inhibit glycolysis rate.Thus,protein S-nitrosylation could play a role in regulating postmortem glycolysis in vitro model even at low pH conditions.

Promotion mechanism of self-transmissible degradative plasmid transfer in maize rhizosphere and its application in naphthalene degradation in soil

Rhizospheres can promote self-transmissible plasmid transfer,however,the corresponding mechanism has not received much attention.Plant-microbe remediation is an effective way to promote pollutant biodegradation;however,some pollutants,such as naphthalene,are harmful to plants and result in inefficient plant-microbe remediation.In this study,trans-fer of a TOL-like plasmid,a self-transmissible plasmid loaded with genetic determinants for pollutant degradation,among different bacteria was examined in bulk and rhizosphere soils as well as addition of maize root exudate and its artificial root exudate(ARE).The results showed that the numbers of transconjugants and recipients as well as bacterial metabolic activities,such as xylE mRNA expression levels and catechol 2,3-dioxygenase(C23O)activ-ities of bacteria,remained high in rhizosphere soils,when compared with bulk soils.The number of transconjugants and bacterial metabolic activities increased with the increasing exudate and ARE concentrations,whereas the populations of donor and recipient bacteria were substantially unaltered at all concentrations.All the experiments consistently showed that a certain number of bacteria is required for self-transmissible plasmid transfer,and that the increased plasmid transfer might predominantly be owing to bacterial metabolic activ-ity stimulated by root exudates and ARE.Furthermore,ARE addition increased naphthalene degradation by transconjugants in both culture medium and soil.Thus,the combined action of a wide variety of components in ARE might contribute to the increased plasmid transfer and naphthalene degradation.These findings suggest that ARE could be an effectively al-ternative for plant-microbe remediation of pollutants in environments where plants cannot survive.