Construction and characterization of the stk and stp1 knockout mutant in streptococcus suis type 2 / 医学研究生学报

Objective Serine /threonine kinases (STK) and phosphatases (STP) regulate various physiological activities of prokaryotes by reversible phosphorylation of proteins .This paper aimed to study the effects of simultaneous deletion of the stk and stp1 genes on the biological characteristics and pathogenicity of streptococcus suis type 2, the Chinese virulent strain 05ZYH33. Methods The double mutant of the stk and stp1 genes of 05ZYH33 was constructed by homologous recombination .The biological characteristics of the wild strain 05ZYH33 and the mutant strain Δstk/stp1 were compared.The effects of the stk and stp1 deletion on bacterial virulence was analyzed using cell adhesion assay , anti-phagocytosis assay and the mouse model of infection . Results RT-PCR showed that the stk and stp1 genes were replaced by the spectinomycin resistance gene Spc r and the mutant strain was successfully constructed .Experi-ments of biological characterization revealed gradually increased value of 05ZYH33 and Δstk/stp1 at 2 hours after inoculation and a plateau period at 7 hours.The logarithmic phase of the mutant strain (A600≈0.4) was 1 hour later than that of the wild one , and the bacterial den-sity of the former was lower than that of the latter after the plateau pe -riod (0.8 vs 1.0).On the blood plates of 05ZYH33 and Δstk/stp1 were observed greyish, round, semitransparent, wet and smooth-sur-faced tiny bacterial colonies , around which there were hemolysis rings with no significant differences in colony morphology and hemolytic ac -tivity.In the experiment on pathogenicity , the mice of the 05ZYH33 group all died within 12 hours while 9 of the 30 mice in the Δstk/stp1 group died within 12 hours and all died within 24 hours. Conclusion The simultaneous deletion of the stk and stp1 genes may mainly affect the regulation of the proteins associated with bacte -rial proliferation and division.

Differential gene expression profile of keloids: a study with cDNA microarray / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the differentially expressed genes in keloids in comparison with normal skin using cDNA microarray.</p><p><b>METHODS</b>The cDNA microarray consisting of 8064 clones of human genes was employed to detect and screen the differentially expressed genes in keloid and normal skin tissues. Semi-quantitative RT-PCR was applied to verify the results of gene microarray.</p><p><b>RESULTS</b>Totally 277 differentially expressed genes were identified in keloids in comparison with normal skin tissue, including 163 up-regulated genes and 114 down-regulated ones according to the designed data filter criteria. These differentially expressed genes belonged to 26 different functional gene families involving different biological processes. RT-PCR yielded results were consistent with those of microarray study.</p><p><b>CONCLUSION</b>A variety of genes are involved in the formation of keloids. The 277 differentially expressed genes comprise the differential gene expression profile of keloids and describe the general changes in the gene expressions in keloid at transcriptional level. Further analysis of the identified genes might help reveal the molecular mechanism of abnormal scarring.</p>

The retrospective analysis of HBV and HCV infection in cholangiocarcinoma / 中华外科杂志

<p><b>OBJECTIVE</b>In order to study the diagnosis and treatment of HBV and HCV infection.</p><p><b>METHODS</b>We retrospectively analysed clinical data of 680 patients with cholangiocarcinoma from 1995 to 2001 and stated by SPSS software.</p><p><b>RESULTS</b>(1) The fastigium of cholangiocarcinoma was 60 - 65 years old. The incidence of cholangiocarcinoma was higher in aged males and the sex ratio (male:female) was 1.36:1. (2) The proximal cholangiocarcinoma was most (41.6%) and distant cholangiocarcinoma was secondly (28.7%). (3) Most patients of cholangiocarcinoma were late. The resection rate was low and the rate of radical operation was 21.6% (147/680). (4) The incidence of proximal cholangiocarcinoma was higher in the positive Serologic marks for HBV and HCV and course of diseases was short. Moreover, the pathology of. positive Serologic marks for HBV and HCV trended to low-differentiation and invasion, metastasis and the resection rate was lower.</p><p><b>CONCLUSIONS</b>Cholangiocarcinoma is common in the aged males. The infection of HB(C)V and hilar cholangiocarcinoma are correlated and incline to the proximal bile duct. The hilar cholangiocarcinoma infected HB(C)V may have higher malignant degree in biological characteristics and more badly prognosis.</p>