Improvement of natural product production in Streptomyces by manipulating pathway-specific regulators / 生物工程学报

Streptomyces are major sources of bioactive natural products. Genome sequencing reveals that Streptomyces have great biosynthetic potential, with an average of 20-40 biosynthetic gene clusters each strain. However, most natural products from Streptomyces are produced in low yields under regular laboratory cultivation conditions, which hamper their further study and drug development. The production of natural products in Streptomyces is controlled by the intricate regulation mechanisms. Manipulation of the regulatory systems that govern secondary metabolite production will strongly facilitate the discovery and development of natural products of Streptomyces origin. In this review, we summarize progresses in pathway-specific regulators from Streptomyces in the last five years and highlight their role in improving the yields of corresponding natural products.

Advances in research of the pathogenesis of norovirus / 临床儿科杂志

Norovirus is one of the main pathogens causing nonbacterial gastroenteritis in infants and young children. Clinical symptoms in norovirus infection include nausea, vomiting, diarrhea, abdominal pain among which vomiting is obvious. Due to the lack of effective research models, the pathogenesis of Norovirus infection is still unclear. This article focuses on the progress in research of the pathogenic mechanism of Norovirus, and mainly discusses the cell phagocytosis and immune response.

Effect of ganciclovir on cytokine levels in infants with cytomegalovirus hepatitis / 第三军医大学学报

Objective To investigate the changes of serum cytokines IL-2,IL-8,IL-10 and IFN-? in infants with cytomegalovirus hepatitis before and after ganciclovir treatment,and explore the underlying mechanisms of ganciclovir and the immunological changes in the development and progression of cytomegalovirus(CMV) infection.Methods CMV-IgM in the serum samples of 72 infants with identified cytomegalovirus infection were measured by enzyme-linked immunosorbent assay(ELISA).CMV DNA in blood was measured by quantitative PCR.CMV-IgM(+) and CMV DNA(+) were as observed group 1(35 cases,without hepatitis).Those with abnormality of ALT were regarded as observed group 2(37 cases,with hepatitis).Another 30 matched healthy infants were enrolled as healthy control group.Levels of serum IL-2,IL-10,IL-8 and IFN-? of each group were examined by ELISA,and CMV masculine hepatitis group were cured with ganciclovir(5mg/kg,i.v.,twice per day for 14 d,and then once per day for 14 d after a 7 days'interval),then the levels of above factors were examined again.Results The levels of IL-8 and IL-10 in observed group 1 were significantly higher than those in healthy control group(t=3.74,9.56;P0.05).After ganciclovir treatment,the level of IL-2 in observed group 2 was significantly higher than that in observed group 1(t=3.41,P0.05).The levels of IL-8,IL-10 and IFN-? were decreased significantly(t=6.52,7.24,14.23;P

Changes of serum cytokines and their clinical significance in infants with cytomegalovirus infection / 第三军医大学学报

Objective To investigate the changes of serum cytokines and explore their role in infants with cytomegalovirus (CMV) infection. Methods We recruited 41 positive CMV-IgM plus normal ALT infants (other disease group), 30 positive CMV-IgM plus abnormal ALT infants (hepatitis group) and 30 healthy infants (control group) in the study. The levels of tumor necrosis factor-?(TNF-?), interferon-?(IFN-?) and interleukin-4 (IL-4) in serum were measured with ELISA. The association between TNF-? and ALT was analyzed. Results The levels of TNF-?, IFN-?, IL-4 were higher, and IFN-?/IL-4 was significantly lower in the two CMV infection groups than the control group. Compared with other disease group, the changes of TNF-?, IL-4, and IFN-?/IL-4 showed significance in hepatitis group. The level of TNF-? showed a positive association with ALT in hepatitis group(r=0.76,P

The disposition and drug resistance of the common pathogenic bacteria among the in-patients and out-patients in the Chongqing and near by regions / 重庆医科大学学报

Objective:To fathom the disposition and drug resistance of the common pathogenic bacteria,separated from various kinds of samples of in-patients and out-patients in hospitals of the western areas in 2006.Method:The assay and analysis of drug resistance in accordance with the sceptor microbiological manual system set by BD company,or with Biomerieux Vitek-32 manual system.Results:In 2006,1 900 strains of pathogenic bacteria were separated,1 210 of which were negative bacilli (63.68%);585 out of 1 900 strains were positive coccobacteria(30.79%).Imipenem has natural drug resistance against Stenotrophmomas maltophilia,and among all of the tested antibacterials,There were 105 strains of fungi.it has the most powerful antibacterial activity against other negative bacilli.There were a remarkable distinction(P