ABSTRACT
Microgravity is a typical feature of the space. A large number of space flights and foundation simulation experiments have shown that cells show typical biological characteristics of aging, such as reduced cell proliferation and cell cycle arrest under microgravity or simulated microgravity. However, the molecular mechanism by which microgravity or simulated microgravity affects cellular senescence is not well understood. Understanding the mechanism controlling cellular senescence induced by microgravity environment is helpful for exploring anti-aging strategies and targeted interventions in space. In recent years, domestic and foreign scholars have carried out a number of researches and explorations on the effect of microgravity and simulated microgravity on cellular senescence as well as the related mechanisms. In this review, the latest research progress of this filed was summarized.
ABSTRACT
Background@#African swine fever virus (ASFV), classical swine fever virus (CSFV), and porcine reproductive and respiratory syndrome virus (PRRSV) are still prevalent in many regions of China. Co-infections make it difficult to distinguish their clinical symptoms and pathological changes. Therefore, a rapid and specific method is needed for the differential detection of these pathogens. @*Objectives@#The aim of this study was to develop a multiplex real-time quantitative reverse transcription polymerase chain reaction (multiplex qRT-PCR) for the simultaneous differential detection of ASFV, CSFV, and PRRSV. @*Methods@#Three pairs of primers and TaqMan probes targeting the ASFV p72 gene, CSFV 5′untranslated region, and PRRSV ORF7 gene were designed. After optimizing the reaction conditions, including the annealing temperature, primer concentration, and probe concentration, multiplex qRT-PCR for simultaneous and differential detection of ASFV, CSFV, and PRRSV was developed. Subsequently, 1,143 clinical samples were detected to verify the practicality of the assay. @*Results@#The multiplex qRT-PCR assay could specifically and simultaneously detect the ASFV, CSFV, and PRRSV with a detection limit of 1.78 × 10 0 copies for the ASFV, CSFV, and PRRSV, but could not amplify the other major porcine viruses, such as pseudorabies virus, porcine circovirus type 1 (PCV1), PCV2, PCV3, foot-and-mouth disease virus, porcine parvovirus, atypical porcine pestivirus, and Senecavirus A. The assay had good repeatability with coefficients of variation of intra- and inter-assay of less than 1.2%. Finally, the assay was used to detect 1,143 clinical samples to evaluate its practicality in the field. The positive rates of ASFV, CSFV, and PRRSV were 25.63%, 9.36%, and 17.50%, respectively. The co-infection rates of ASFV+CSFV, ASFV+PRRSV, CSFV+PRRSV, and ASFV+CSFV+PRRSV were 2.45%, 2.36%, 1.57%, and 0.17%, respectively. @*Conclusions@#The multiplex qRT-PCR developed in this study could provide a rapid, sensitive, specific diagnostic tool for the simultaneous and differential detection of ASFV, CSFV, and PRRSV.