ABSTRACT
Objective The magnetic beads direct adsorption method was used to extract the cell-free DNA (cfDNA) from three kinds of human humoral biological samples, including urine, saliva and blood, as to provide a reference for forensic cfDNA research and forensic inspection. Methods The cfDNA was isolated from humoral samples by centrifuging, and the cfDNA was extracted with the method of magnetic beads direct adsorption. Then the samples were sequentially amplified with Identifiler-Plus amplication kit, and the STR genotyping was detected by ABI 3500 Analyzer. Results The cfDNA was detected from all the three kinds of samples. The detection rate of cfDNA from the blood samples was 100%, the saliva was 90%, and the urine was 70%. Conclusion The results suggest that human humoral biological samples contain cfDNA. What's more, the magnetic beads direct adsorption method can be used to extract cfDNA efficiently and conveniently.
ABSTRACT
Different types of acids from fermentation environment or industrial microorganisms exist during fermentation process. Acids may inhibit growth and metabolism of industrial strains, namely acid stress. The tolerance mechanisms of acid stress include regulation of intracellular proton concentration, protection and restoration of intracellular macromolecules, changes in cell membrane composition and acid stress response at whole cell level. Screening and modification methods have been applied to improve acid-stress tolerance of industrial strains for decades. In this review, we provide insights into acid-stress tolerance of industrial microorganisms and address the modification of microbial pathways to improve acid-stress tolerance.