AIM To study the effects of Lotusine(Lot), a pure alkaloid extracted from the green seed embryo of Nelumbo nucifera Gaertn, on the action potentials(APs) in myocardium and slow inward current(Isi) in cardiac Purkinje fibers(PF). METHODS standard microelectrode and two microelectrodes voltage clamp techniques were used. RESULTS Lot 1～100 ?mol?L -1 could concentration dependently prolonged APD 20 and APD 90 of fast AP and increase the contractile force(Fc) in guinea pig papillary muscles. In papillary muscles pretreated with reserpine, similar results were also observed but the effect of Lot was weaker than those pretreated without reserpine. In guinea pig left atria, Lot 30 ?mol?L -1 could partly antigoniste the shortening APD effect of acetylcholine. Lot 3～100 ?mol?L -1 could enhance the action potential amplitude(APA)and maximal velocity of phase 0 depolarization ( V max ) of slow AP of papillary muscles induced by high K + (24 mmol?L -1 )and isolated sinoatral node(SAN) pacemaker cells of rabbits with dose dependent manner,But not obvousely short the sinus cycle length of SAN. Moreover, Lot increased the Isi of in canin cardiac PF with with time dependent and dose dependent manner. CONCLUSION The results suggest that Lot has effect of prolongation of APD and increase of Ca 2+ influx and these are very important in contribution to its positive inotropic effect, which may be related to inhibition of phosphodiesterase Ⅲ.

Objective To create new tetraploid resource of Dioscorea zingiberensis in the hope of potential breeding materials with high yield and high level of diosgenin. Methods Callus with tiny green buds were directly soaked in colchicine solution or cultured in medium plus with colchicine to prohibit the isolation of chromosomes and induce tetraploid mutants. Results Tetraploids were achieved successfully. The most efficient treatment for inducing tetraploid was soaking the tiny buds in 1?103 mg/L colchicine solution for 24 h, the inducing rate could be up to 35. 2%. The induced tetraploids exhibited notable difference with common wild type (diploids) in morphology, physiology, and microscopic structure. ConclusionThe tetraploid plants show the advantages of gigantic size and vigorous growth. Thus, the established technique system to induce tetraploid from tissue cultured callus would provide an efficient alternative pathway for medicinal plants of Dioscorea L. breeding.

Objective By comparing the physiological index and diosgenin content of rhizome between the artificial tetraploid and the wild type diploid of Dioscorea zingiberensis, it is aimed at revealing the potential utility of polyploid breeding in medicinal D. zingiberensis. Methods Three clones of the natural diploid and the artificially induced tetraploid of D. zingiberensis were used as materials in this study. The content of SOD, PPO, and soluble sugar of leaves was determined by spectrophotometry, CAT content was measured by using the method of KMnO_4 titration. And the diosgenin content in rhizome was analyzed by HPLC. Results The tetraploid plants showed higher level of SOD, PPO, CAT, soluble sugar content in leaves, and diosgenin content in rhizome than those of the diploid origins. The diosgenin content in the three clones of tetraploid plants increased to 27% as compared to wild type. Conclusion Artificially induced tetraploid presents high content of diosgenin and great potential in stress resistance, which would be available in good seed breeding for high yield of diosgenin.

Objective To investigate the epididymal sperm ultrastructure after vasectomy. Methods During the operation of vasovasostomy (38 cases, test group) and vasectomy (13 cases,control group,group A) the proximal vas deferens fluids were collected.The epididymal sperm morphology in the proximal vas deferens fluids was observed using optical and electronic microscopes.Data were analyzed by SPSS program. Results The data from group A showed that there was no significant difference between left and right side in the percentage of normal sperm morphology.The results from both optical and electronic microscopes showed that there was a significant difference in the percentage of normal sperm morphology (a),abnormal sperm head (b),sperm with neck defect (c) and sperm with tail defect (d) between group A and group B(5 years after vasectomy). (electronic microscopes:(a):(40.28?11.53)% vs (16.80?7.93)%,(6.29? 4.57 )%,( 4.63? 5.06 )%; (b):(35.00?14.18)% vs (59.05?14.44)%,(63.43?15.23)%,(82.05? 16.71 )%;(c):(20.83? 6.40 )% vs (13.60?6.78)%,( 14.71? 6.82)%,(9.00?7.18)%;(d):(3.89?4.44)% vs (10.55?11.73)%,(15.57?9.81)%,(4.32?7.65)%. optical microscopes:(a):(49.12?20.55)% vs (19.95?15.42)%,(10.00?9.50)%,(5.84?9.63)%; (b):(35.00?14.55)% vs (22.55?16.24)%,(14.71?15.78)%,(10.68?18.65)%; (d):(15.80?9.55)% vs (57.50?24.74)%,(75.29?23.90)%,(78.21?30.33)%.There existed multi-cell organ and multi-form abnormalities in the inner structures of sperm heads,necks and tails. Conclusions The epididymal sperm defect (including head, neck and tail) after vasectomy was demonstrated in the inner cell organs.The longer after vasectomy, the higher percentage of sperm with abnormality was found.

Objective: To investigate the antibiotic resistance spectrum and genetic characteristics of multidrug-resistant Staphylococcus aureus(MDRSA) nasal isolate among primary school students, and to provide a scientific basis for the prevention and control of masal MDRSA resistance and the selection of clincal drugs in children. Methods: Antibiotic susceptibility experiments were performed on all SA isolates of 1 705 primary school students from 8 primary schools in Guangzhou selected by using multistage cluster stratified sampling method. MDRSA antibiotic susceptibility spectrum was analyzed, and the resistant, virulence and immune evasion cluster(IEC) genes detected by polymerase chain reaction(PCR). Results: The prevalence of MDRSA nasal carriage was 20.76%(354/1 705), and the proportion of multidrug resistance among SA isolates was 96.20%(354/368). The predominant resistant antibiotics of MDRSA isolates were penicillin(99.72%), erythromycin(96.33%), clindamycin(90.96%) and teicoplanin(90.11%). Notably, 240(67.80%, 240/354) MDRSA isolates were resistant to more than six antimicrobial categories. And the predominant detection rates of resistant genes were BlaZ(92.66%), Tet(M)(49.72%), virulence genes Tst(25.42%) and IEC genes Sak(92.09%), Hlb(61.58%). Conclusion We found high prevalence of nasal colonization MDRSA from healthy children. Moreover, MDRSA isolates has a high resistant rate to multiple antibiotics, and the proportion of resistant to ≥6 antimicrobial categories is high.

Objective: To investigate the contamination, antimicrobial resistance and virulence genes of S. aureus from toilets of primary schools in Guangzhou. Methods: The surface samples of toilets were collected from eight primary schools in Guangzhou from May to July 2016. The standard microbiological assays, disk diffusion methods and PCR technique were used for the isolation and identification, antimicrobial resistance and virulence genes of S. aureus . Results: The contamination rate of S. aureus and MRSA was 6.25% and 3.13%, respectively. There was significant difference in the contamination rate of S. aureus among different sampling sites ( χ 2=15.15, P <0.01) and the highest contamination rate was on the ground (15.00%).The most predominant antibiotic for S. aureus was penicillin (100.00%) and the proportions of resistant to teicoplanin, erythromycin,rifampicin, clindamycin and linezolid were more than 75.00%.The multidrug resistant rate of S. aureus was 85.00%.The detection rate of virulence genes of S. aureus was sea (50.00%), tst (30.00%), etb (15.00%), eta (10.00%), seb (10.00%) and pvl (5.00%), respectively. Conclusion The contamination rate of S. aureus from toilets of primary schools in Guangzhou is in a lower level among similar researches. However, the contamination of MRSA is serious, which accounts for half of S. aureus . In addition, S. aureus isolates show high multi-drug resistant rate and high detection rate of virulence genes.

Rv2742 is a novel gene identified from Mycobacterium tuberculosis H37Rv by the proteogenomics strategy. The aim of this study was to establish a system of soluble expression and purification of the missing protein Rv2742 in M. tuberculosis H37Rv, to provide reference for further research on the biological function of Rv2742. The soluble protein was not successfully induced by prokaryotic expression vectors pGEX-4T-2-Rv2742, pET-32a-Rv2742, pET-28a-Rv2742 and pMAL-c2X-Rv2742. After the codon of novel gene Rv2742 was optimized according to E. coli codon usage frequency, only the recombinant strain containing plasmid pMAL-c2X-Rv2742 could produce soluble products of Rv2742 encoding gene. In addition, the expression effects of the desired fusion protein were also analyzed under different conditions including hosts, culture temperatures and IPTG concentrations. The optimum expression conditions were as follows: Rosetta (DE3) host, 16 °C culture temperature and 0.5 mmol/L IPTG. After being purified by affinity chromatography with amylose resin, the fusion protein sequence was confirmed by LC-MS/MS. These results indicated that the novel gene Rv2742 product could be successfully induced and expressed in a soluble form by the expression system pMAL-c2X with MBP tag. Our findings provide reference for studies on potential interaction and immunogenicity.
Chromatography, Liquid ; Cloning, Molecular ; Escherichia coli ; Mycobacterium tuberculosis ; genetics ; Recombinant Fusion Proteins ; Tandem Mass Spectrometry