Objective To investigate the genetic mutation of the norA gene and its promotor from the wild-type drug-resistance Staphylococeus aureus(S.aureus)strains. Methods A total of 10 antibiotic-resistant S.aureus strains were isolated and screened from the burn wound for the sequencing and analysis of the nora gene and its promoter. Results There isolated 87 S.aureus strains from the burn wound flora,which were completely sensitive to vacomycin,highly sensitive to Quinupristin and Nitrofurantoin,but highly resistant to the other antibiotics,even up to91.7% of MRSA.There found the same point mutation(G→A) located at 1 349 sites of the norA gene coding region in all the S.aureus strains,saying that the amino acid was changed from Gly(glycin)to Asp(agpartic acid) in 291 sites.The resetpine reverse test showed that the MICs value of three antibiotics was lowered at various degrees in all 10strains.Conclusion NorA gene mutation is one of the mechanisms for antibiotic-resistance of S.aureus.

Objective To investigate the diagnostic value of microscopic observation drug susceptibility assay (MODS) in extrapulmonary tuberculosis. Methods MODS technology was constructed by using 24-well cell culture plate and liquid culture.Ziehl-Neelsen smear,Lowenstein-Jensen culture and MODS were used to detect Mycobacterium tuberculosis in 74 pleural fluid samples collected from patients with tuberculous pleurisy,63 cerebrospinal fluid samples collected from patients with tuberculous meningitis and 18 samples collected from non-tuberculosis suspects.The immunochromatography was used to distinguish Mycobacterium tuberculosis from nontuberculosis mycobacteria. The results of Ziehl-Neelsen smear, Lowenstein-Jensen culture and MODS were compared by x2 test.Results The positive rates of MODS,Lowenstein-Jensen culture and Ziehl-Neelsen smear were 58.1 ％ (43/74),18.9 ％ (14/74 ) and 6.8％ (5/74),respectively in tuberculous pleurisy patients; 54.0％(34/63),20.6％ (13/63) and 4.8％ (3/63),respectively in tuberculous meningitis patients.The positive rate of MODS technology was significantly higher than that of Lowenstein Jensen culture in tuberculous pleurisy patients (x2 =24.00,P＜0.01) and tuberculous meningitis patients (x2 =14.97,P ＜ 0.01). Each Mycobacterium obtained from MODS and Lowenstein-Jensen culture was identified as Mycobacterium tuberculosis by immunochromatography.All of the 18 pleural fluid and cerebrospinal fluid samples which collected from non-tuberculosis suspects were all negative detected by Ziehl-Neelsen smear,Lowenstein-Jensen culture and MODS.The median time to culture positive of MODS was 9 days in cerebrospinal fluid and 14 days in pleural fluid samples,which were both significantly shorter than that of Lowenstein-Jensen culture (31 days in both cerebrospinal fluid and pleural fluid samples). Conclusion Compared to conventional microbiological diagnosis methods,MODS is a rapid detection method of Mycobacterium tuberculosis with a higher positive detection rate,which is suitable for rapid diagnosis of extrapulmonary tuberculosis.

Objective To investigate the effects of pyrroloquinoline quinone(PQQ) on the hippocampal neurons of aged rats induced by D-galactose(D-gal).Methods D-gal was used to induce the model of aging rat,PQQ was administered into rat lateral intracerebroventricle.After 50 days the metamorphosis of hippocampal neurons was observed by H-E and Nissl's staining.The apoptosis rate of hippocampus was tested by flow cytometry.The contents of free radical and C-FOS protern were measured.Results Compared with the control group,the size of the neurosoma was slightly changed,the optical density of Nissl's was decreased,the content of free radical and the apoptosis rate increased markedly in D-gal group.After PQQ injection with D-gal,the size of neurosoma and the optical density of Nissl's were markedly increased,the content of free radical and the apoptosis rate of hippocampus did not change.PQQ improved the expression of C-FOS protern.Conclusion PQQ can slow down the aging progress of hippocamal neurons induced by D-gal.

Objective:To investigate the implementation effect of micro-video assisted physiological theory teaching based on functional experiments.Methods:There were 140 clinical undergraduates (control group) from Class 1 and Class 2, and 123 clinical undergraduates (experimental group) from Class3 and Class 4 of Batch 2017 in our university who were involved in this study. The control group adopted traditional teaching method, the experimental group adopted micro-videos to assist traditional teaching in the teaching of selected chapters, and these micro-videos were collected from the recording and editing of functional experiments. After the course, questionnaire survey in terms of course design, implementation and effect, as well as final exanimation performance analysis were conducted to evaluate the teaching effect. SPSS 17.0 was used for t test. Results:The final examination scores of the experimental group were significantly higher than those of the control group [(81.02±9.64) vs. (73.41±11.39)], with significant differences ( t=-5.805, P<0.001). Among them, the scores of Chapter 2 of the two groups were [(8.07±0.94) vs. (6.14±1.05), t=-15.616, P<0.001)], the scores of Chapter 4 were [(16.16±1.79) vs. (10.90±2.23), t=-20.903, P<0.001)], and the scores of Chapter 6 were [(6.04±0.53) vs. (5.82±0.78), t=-2.638, P=0.009)], all with significant differences. 100% of questionnaires were recovered, and more than 90% of students were interested in this teaching method which could strengthen their understanding of the key and difficulties in physiology and was also helpful to cultivate their ability of induction and summarization. Conclusion:Micro-videos based on functional experiments assisted teaching can improve the teaching effect of physiology, and it's worth popularizing.

By analyzing the shift of microbial communities under different iron/sulfur ratios, the response of metallurgical microorganisms to energy substrates was investigated based on molecular ecological networks. High-throughput sequencing of microbial samples from different domesticated batches was conducted to analyze the changes in community composition, alpha and beta diversity. Based on the molecular ecological network, the interactions between microorganisms under different iron/sulfur ratios were explored. Keystones were identified to analyze the community response to energy substrates. In the process of domestication based on different energy substrates, the dominant species in the in iron-rich and sulfur-less community were Acidithiobacillus ferrooxidans and A. ferriphilus. A. thiooxidans accounted for up to 90% in the sulfur-rich and iron-less community after 3 domesticating batches. The results of alpha and beta diversity analysis show that the domestication process of sulfur-rich and iron-less substrates reduced the diversity of microbial communities. Molecular ecological network analysis shows that the keystones were all rare species with low abundance. During the domestication by sulfur-rich and iron-less energy substrates, the bacterial species had a closer symbiotic relationship and the community was more stable. Through this domestication experiment, the impact of different energy substrates on microbial aggregation was clarified. Domesticating metallurgical microorganisms by using sulfur-rich and iron-less energy substrates made the microbial colonies to be more stable, which was conducive to the oxidation of iron and sulfur, promoting the dissolution of sulfide minerals. Our findings provide a reference for the directional domestication of metallurgical microorganisms.
Acidithiobacillus/genetics* ; Iron ; Minerals ; Oxidation-Reduction ; Sulfur