ABSTRACT
The plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are native species unique to the Qinghai-Tibetan Plateau with successful adaptation to the hypoxic environment. In this study, the number of red blood cells, hemoglobin concentration, mean hematocrit and mean volume of red blood cells were measured in plateau zokors and plateau pikas at different altitudes. Hemoglobin subtypes of two plateau animals were identified by mass spectrometry sequencing. The forward selection sites in two animals' hemoglobin subunits were analyzed by PAML4.8 program. Homologous modeling was used to analyze the effect of forward selection sites on the affinity of hemoglobin to oxygen. The adapting strategies of plateau zokors and plateau pikas to hypoxia at different altitudes were analyzed through comparing blood parameters between the two species. The results indicated that, with increasing altitudes, plateau zokors responded to hypoxia by increasing red blood cell count and decreasing red blood cell volume, while plateau pikas took the opposite strategies to plateau zokors. In erythrocytes of plateau pikas, both adult α2β2 and fetal α2ε2 hemoglobins were identified, while erythrocytes of plateau zokors only had adult α2β2 hemoglobin, however the affinities and the allosteric effects of the hemoglobin of plateau zokors were significantly higher than those of plateau pikas. Mechanistically, in the α and β subunits of hemoglobin of plateau zokors and pikas, the numbers and the sites of the positively selected amino acids as well as the side chain groups polarities and orientations of the amino acids differed significantly, which may result in the difference of the affinities to oxygen of hemoglobin between plateau zokors and pikas. In conclusion, the adaptive mechanisms to respond to hypoxia in blood properties of plateau zokors and plateau pikas are species-specific.
Subject(s)
Animals , Altitude , Amino Acids , Hemoglobins , Hypoxia , LagomorphaABSTRACT
Objective To select more rapid,sensitive and specific method in detection of respiratory syncytial virus(RSV)directly from clinical specimens.Methods RSV was detected by virus isolation in tissue culture,direct smears and detection by indirect immunofluorecence assay(IFA),rapid culture assay,sandwich enzyme linked immunosorbent assay(ELISA)as well as labbed streptavidin biotin method(LSAB)from 45 specimens(nasopharyngeal aspirates,NPAs) collected from infants and young children with acute lower respiratory tract infection.Results Of 45 NPAs,12 cases(26.7%) were positive by virus isolation,14 cases(31.1%) were positive for RSV by direct detection of RSV antigen by IFA,20 cases(44.4%) were positive with rapid culture assay,4 cases(8.9%)were positive by sandwich ELISA,4 cases(8.9%)were positive by LSAB.Conclusion Rapid culture assay and direct detection of RSV in NPAs direct smears by IFA are rapid,sensitive method in the diagnosis of RSV infections.