Particle Sizes and Antibacterial Activity of Radix Astragalus and Radix Isatidis Ultrafine Powders

Using 9200 laser particle size analyzer and KYKY-2800 scanning electron microscope, particle sizes and cellular morphology of Radix Astragalus and Radix Isatidis ultrafine powders were observed. According to the results, the particle size of 89. 1 % of Radix Astragalus ultrafine powders ranged from 1.729 [xm to 44.938 ｜xm, Z ）50 =4.368 ｜xm; the particle size of 93.411% of Radix Isatidis ultrafine powders ranged from 1.510 [xm to 44.938 ｜xm, Z ）50 = 8 .7 2 6 [xm. Radix As-tragalus and Radix Isatidis ultrafine powders were pulverized completely without intact cellular morphology. The antibacterial activity of Radix Astragalus and Radix Isatidis ultrafine powders against chicken-derived E. coli （078） was investigated. The results indicated that Radix Astragalus and Radix Isatidis ultrafine powders exhibited higher antibacterial activity against chicken-derived E. coli （078 ） compared with the corresponding coarse powders. This study laid a solid foundation for the development and application of Chinese medicine ultrafine powder preparations.

PCR Detection of Pilus-associated Genes and Serotype Identification of Pathogenic Escherichia coli Isolated from Chickens in the Jidong Area

[ Objective] This study aimed to explore the presence of type I pill （fimC gene） and P pill （papC gene） and identify the serotype of pathogenic E. coli isolated from chickens in the Jidong Area. [ Method] Type I pill （fimC gene） and P pill （papC gene） were detected by PCR. The serotype was identified by con- ventional agglutination test. [ Result ] The results showed that 100% of chicken-derived E. coil strains expressed type I pill （fimC gene） ; 39.1% （9/23） of chick- en-derived E. coli strains expressed P pill （papC gene）. In addition, 23 isolates of chicken-derived E. coil were assigned to 14 O serotypes, including O78, O93, O 45, O101, O38, O88, O24, O1, O163, O53, O15, O87, O34 and O29, among which O78 was the dominant serotype that accounted for 42.8% （6/14） of the total strain number. [ Conclusion] Chicken-derived E. coli strains in the Jidong Area belonged to 14 serotypes, and 078 was the dominant serotype; 83.3% of 078 serotvDe E. coli strains expressed both tvDe I Dill and P Dill.

Phylogenetic Analysis of Virulence Factor Genes in Salmonella from Chicken

Salmonella is a common genus of seriously harmful food-borne zoonotic bacteria. Humans and animals may be infected with Salmonella through ingestion of SalmoneUa-contaminated eggs and poultry meat. Therefore, in order to reduce the incidence of Salmonella infections, it is crucial to explore the pathogenic mech- anism of Salmonella. invA and invE are major virulence factor genes that encode invasion proteins of Salmonella. In order to explore the pathogenic mechanism of Salmonella, phylogenetic analysis of major virulence factor genes in 33 Salmonella strains isolated from chicken was analyzed. According to the results, ivnA gene was successfully amplified from 33 Salmonella strains; ivnE gene was successfully amplified from 32 Salmonella strains, ivnA nucleotide sequences shared 72.9% - 97.6% homology among 12 sequenced Salmonella strains and shared 78.9% - 97.2% homology with those in GenBank ; ivnE nucleotide sequences shared over 95.3% homology among 23 sequenced Salmonella strains and shared 89.6% -98.6% homology with those in GenBank, which exhibited no genetic relationship to other organisms. This study provided the basis for rapid molecular detection, epidemiological research and molecular pathogenesis analysis of Salmonella.