Denitrification plays an important role in wastewater treatment systems for the reason that the nitrate or nitrite was reduced, and some gases such as NO, N_2O or N_2 were released. The application of denitrification in wastewater, the mechanism of denitrification, and the effect factors of denitrification were introduced in this paper. The communities of Denitrifying bacteria, and some key enzymes of denitrification were also introduced. The discovery of aerobic denitrifying bacteria, autotrophic denitrifying bacteria, and denitrifying Phosphorus-removing Bacteria were also mentioned in this paper.

ObjectiveTo conduct a molecular epidemiological study on human metapneumovirus (hMPV) among pediatric patients in Guangzhou. MethodsA total of 1 840 clinical specimens were obtained from pediatric patients with respiratory infections in Guangzhou Women and Children' s Medical Center in 2010.hMPV was detected by real-time TaqMan RT-PCR in clinical specimens.F gene was amplified and the PCR-products were directly sequenced. ResultsIn 1 840 clinical specimens, 66 werehMPV-positive with a positive rate of 3.59％. hMPV was detected in all specimens except those collected in September and October, and the highest positive hMPV rate occurred in April (6.09％). The F genes of 3 randomly selected strains and hMPVgz01 ( isolated in 2008) were compared with subgroups A1, A2, B1,B2 and C, and the highest homology was with BJ1887 strain of genotype A2b (97％). The F genes of the randomly selected strains and hMPVgz01 were 99％ identical to each other. Sequences and phylogenetics analysis revealed that the epidemical strain in Guangzhou belonged to genotype A2b. ConclusionhMPV is prevalent in spring and summer among children in Guangzhou, and A2b is the predominant genotype.

OBJECTIVETo study the characteristics of changes of LDH enzyme patterns of mice under slight hypoxia.

METHODSMice treated with artificial hypoxia, various tissues were made for the test of LDH enzymatic activity by the specific staining technique. LDH (1-5) relative percentage enzymatic activity (RPEA) were measured with CS-910 dual-wavelength thin layer chromatography scanner.

RESULTSThe RPEA of LDH isozymes of various tissues after slight hypoxia shifted to the isozymes LDH1 and LDH2, whose principal subunits are H subunits, and the RPEA of LDH1 (H4), LDH2 (H3M) increased, while RPEA of LDH5 (M4) in various tissues decreased prominently except the cardiac muscle, and that of LDH4 (HM3) decreased as well. After polyacrylamide gel electrophoresis (PAGE) of the hypoxia treated cardiac muscle specimen was made, activity subbands originated regularly in the isoyme patterns of LDH, with the regularity of LDH1 (0 subband), LDH2 (0-1 subbands), LDH3 (0-2 subbands), LDH4 (1-3 subbands), LDH5 (2-4 subbands). After adding appropriate amount of NAD+ to the hypoxia treated cardiac muscle specimen, PAGE showed the subbands of four isoymes (LDH2-LDH5) reduced or even totally disappeared in the isozyme patterns.

CONCLUSIONSThe negative feedback regulation of coenzymization and decoenzymization of LDH isozymes is one of the mouse stress responses to slight hypoxia.

Animals ; Hindlimb ; enzymology ; Hypoxia ; enzymology ; Isoenzymes ; metabolism ; L-Lactate Dehydrogenase ; classification ; metabolism ; Liver ; enzymology ; Mice ; Muscles ; enzymology ; Myocardium ; enzymology ; Random Allocation