Analysis of the variation and changes of Yersinia enterocolitica in Ningxia area from 1984 to 2011 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the genetic evolution and bacterial type changes of Yersinia enterocolitica in the Ningxia area between year 1984 and 2011.</p><p><b>METHODS</b>A total of 296 strains of Yersinia enterocolitica was collected from diarrhea patients, pig, rodents, sheep and dogs between year 1984 and 2011. The serotype, biotype, ail, ystA, ystB, yadA, virF and other toxic genes were detected. The PFGE subtypes of serotype O:3 and O:9 strains and the cluster features were analyzed.</p><p><b>RESULTS</b>Out of 296 Yersinia enterocolitica strains, pig was the main host, accounting for 65.20% (193/296), followed by rodents, accounting for 32.43% (96/296). Serotype and biotype had their own respective dominant types in different periods. During 1984 and 1985, 2 strains of serotype O:3 and 3 strains of serotype O:9 were isolated, all belonged to biotype 3. Because of lack of strains, there were no obvious dominant types found. Between 1997 and 1999, 177 strains of serotype O:9 Yersinia enterocolitica were isolated as the dominant strain; and there were 178 strains of biotype 2 Yersinia enterocolitica were found. During 2007 and 2011, 54 strains of serotype O:3 Yersinia enterocolitica were isolated as dominant strain; followed by 26 strains of serotype O:5. There were separately 44 and 59 strains of biotype 1A and biotype 3. The PCR test divided the 248 strains into 4 types, including pathogenic strains as type I (ail(+), ystA(+), ystB(-), yadA(+), virF(+)). The PFGE divided the serotype O:3 into 12 types, in which K6GN11C30021 and K6GN11C30012 were the dominant types, accounting for 63.64% (42/66). The serotype O:9 were divided into 14 types, in which K6GN11C90010, K6GN11C90008, K6GN11C30018 and K6GN11C90003 were the dominant types, accounting for 89.01% (162/182).</p><p><b>CONCLUSION</b>The different serotypes of isolated strains in Ningxia district showed different dominant bacteria in different periods; while the biotypes also changed with serotypes. The Yersinia enterocolitica isolated from different years showed great variation.</p>

Characteristics of Yersinia enterocolitica genes isolated in Ningxia Hui autonomous region from 1997 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the distribution of virulent genes of Yersinia enterocolitica (Y. enterocolitica) in Ningxia Hui autonomous region and the characteristics of the molecular patterns of Y. enterocolitica.</p><p><b>METHODS</b>283 strains of Y. enterocolitica were isolated in Ningxia Hui autonomous region between year 1997 and 2010. The genes ail, ystA, ystB, yadA and virF were analyzed by PCR method; the chromosomal DNA of Y. enterocolitica was digested by restriction endonucleases NotI and processed by pulsed-field gel electrophoreses (PFGE); and then the cluster analysis were conducted by BioNumeric computer software towards the above results.</p><p><b>RESULTS</b>Of all, 209 strains of serotypes O:3 and O:9 Y.enterocolitica showed positive virulence of genes ail, ystA, yadA and virF; 97.6% (204/209) of which, the ystB virulence were negative. The virulence of all genes in serotype O:8 and serum-unclassified strains were negative. 9 out of 11 strains of serotype O:5 Y. enterocolitica showed negative virulence of the above five genes. By PFGE, according to the NotI Macrorestriction Map on chromosomal DNA, the 29 strains of serotype O:3 Y. enterocolitica were divided into 12 PFGE patterns, 2 of which were dominant patterns which could be found in over 5 strains; and the 180 strains of serotype O:9 Y. enterocolitica were divided into 13 patterns, 4 of which were dominant patterns which existed in over 10 strains; which were isolated individually from pigs and house mouse, pigs and dogs as well as pigs and wild rabbits.</p><p><b>CONCLUSION</b>Y.enterocolitica serotypes O:3 and O:9 were pathogenic in Ningxia, and serotype O:3 becomes predominant gradually. O:5, O:8 and serum-unclassified serotypes were non-pathogenic.</p>

Mesoporous organosilicas with ultra-large pores: mesophase transformation and bioadsorption properties.

Large pore ordered mesoporous organosilicas (OMOs) with distinct mesophase structure was synthesized under low temperatures by the co-condensation of 1,2bis(triethoxysilyl)ethane (BTESE) and tetraethyl orthosilicate (TEOS) in acidic solution, using triblock copolymer F127 as a template and 1,3,5-trimethylbenzene (TMB) as a swelling agent. With the decrease of temperature, a mesophase transformation from 2D hexagonal structure (p6mm) via mesostructured cellular foam to a highly ordered 3D cubic structure (Fm3m) was evidenced by small angle X-ray diffraction (SAXS), transmission electron microscopy (TEM) and N(2) sorption. It reveals that the lower synthesis temperatures may influence the hydrolysis and condensation of silica species and the hydrophilic-hydrophobic property of F127, as well as the swelling capacity of F127 micelles with TMB, which resulting in a formation of large pores ordered mesoporous organosilicas with various mesostructures materials. Finally, the enzyme adsorption properties of the OMOs were investigated and the results showed that the OMOs with a 3D large pore structure and regular morphology is much more qualified for enzyme adsorption.

Highly hydrothermally stable microporous silica membranes for hydrogen separation.

Fluorocarbon-modified silica membranes were deposited on gamma-Al2O3/alpha-Al2O3 supports by the sol-gel technique for hydrogen separation. The hydrophobic property, pore structure, gas transport and separation performance, and hydrothermal stability of the modified membranes were investigated. It is observed that the water contact angle increases from 27.2+/-1.5 degrees for the pure silica membranes to 115.0+/-1.2 degrees for the modified ones with a (trifluoropropyl)triethoxysilane (TFPTES)/tetraethyl orthosilicate (TEOS) molar ratio of 0.6. The modified membranes preserve a microporous structure with a micropore volume of 0.14 cm3/g and a pore size of approximately 0.5 nm. A single gas permeation of H2 and CO2 through the modified membranes presents small positive apparent thermal activation energies, indicating a dominant microporous membrane transport. At 200 degrees C, a single H2 permeance of 3.1x10(-6) mol m(-2) s(-1) Pa(-1) and a H2/CO2 permselectivity of 15.2 were obtained after proper correction for the support resistance and the contribution from the defects. In the gas mixture measurement, the H2 permeance and the H2/CO2 separation factor almost remain constant at 200 degrees C with a water vapor pressure of 1.2x10(4) Pa for at least 220 h, indicating that the modified membranes are hydrothermally stable, benefiting from the integrity of the microporous structure due to the fluorocarbon modification.