Construction of EF-G knockdown strain of Mycobacterium smegmatis and drug resistance analysis / 生物工程学报

As the only translational factor that plays a critical role in two translational processes (elongation and ribosome regeneration), GTPase elongation factor G (EF-G) is a potential target for antimicrobial agents. Both Mycobacterium smegmatis and Mycobacterium tuberculosis have two EF-G homologous coding genes, MsmEFG1 (MSMEG_1400) and MsmEFG2 (MSMEG_6535), fusA1 (Rv0684) and fusA2 (Rv0120c), respectively. MsmEFG1 (MSMEG_1400) and fusA1 (Rv0684) were identified as essential genes for bacterial growth by gene mutation library and bioinformatic analysis. To investigate the biological function and characteristics of EF-G in mycobacterium, two induced EF-G knockdown strains (Msm-ΔEFG1(KD) and Msm-ΔEFG2(KD)) from Mycobacterium smegmatis were constructed by clustered regularly interspaced short palindromic repeats interference (CRISPRi) technique. EF-G2 knockdown had no effect on bacterial growth, while EF-G1 knockdown significantly retarded the growth of mycobacterium, weakened the film-forming ability, changed the colony morphology, and increased the length of mycobacterium. It was speculated that EF-G might be involved in the division of bacteria. Minimal inhibitory concentration assay showed that inhibition of EF-G1 expression enhanced the sensitivity of mycobacterium to rifampicin, isoniazid, erythromycin, fucidic acid, capreomycin and other antibacterial agents, suggesting that EF-G1 might be a potential target for screening anti-tuberculosis drugs in the future.

Application of native hapten-gel diffusion test in differential diagnosis of Brucella-infected antibody and S2 or Rev.1-vaccinated antibody / 中国人兽共患病学报

The aim of the present study was to work on the efficiency of differential diagnosis of native hapten-gel diffusion assay (NH-GD) on the background of vaccination with S2 or Rev.1.The conditions of NH-GD assay was firstly optimized,its sensitivity,specificity,repeatability and ability of differential diagnosis were determined respectively,and its test result was compared with that of fluorescence polarization assay (FPA).The results showed NH-GD assay with good specificity and repeatability could differentiate Brucella-infected antibody from vaccinated antibody after vaccination with S2 or 122 days after vaccination with Rev.1.And the result of NH-GD assay was highly consistent with that of FPA,which was simple to operate and needed a few simple equipment.Therefore,NH-GD assay was a good method for sheep brucellosis surveillance in China and especially suitable for application in grass-roots areas.

Effect of MTHFR gene on the schizophrenia and its cognitive function / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the effect of MTHFR gene on schizophrenia and its cognitive function.</p><p><b>METHODS</b>We recruited 254 schizophrenia patients with stable condition, 339 healthy controls for genetic analysis and 72 healthy controls for cognitive evaluation. The repeatable battery for the assessment of neuropsychological status (RBANS) was used for cognitive measurement. PCR-RFLP technique was carried out to genotype 677C/T polymorphism.</p><p><b>RESULTS</b>There were no significant differences in genotypic or allelic frequencies of the 677C/T polymorphism between the case and control groups (P> 0.05). In the RBANS, patients had higher scores of immediate memory, visuospatial skill, language, attention, delayed memory and total scores than healthy controls (P< 0.01); Patients with different genotypes of 677C/T polymorphism had significant differences in the scores of immediate memory, attention and total scores (P< 0.05).</p><p><b>CONCLUSION</b>Our results did not provide evidence for MTHFR gene conferring susceptibility to schizophrenia. However, there was a significant association between the MTHFR gene and cognitive impairment in patients with schizophrenia, especially in immediate memory and attention.</p>

Application of interferon-γ testing and the comparative cervical skin test in herds infected with Mycobacterium bovis / 中国人兽共患病学报

The interferon-γ testing and the comparative cervical skin test were compared with the simple cervical hypersensitivity test routinely used in our country in herds infected with Mycobacterium bovis, in which 167 infected cattle from 5 herds were tested with interferon-γ testing and the comparative cervical test (CCT) simultaneously and other 106 cattle were tested with other hypersensitivity tests used as control for comparison. In these 167 cattle tested with both tests, 89 cattle were proved to be positive both in interferon-γ testing and CCT using the bovine PPD of Netherland with a coincidence rate of 92.7% (89/96). In 106 cattle the coincidence rate of positive reactions detected by γ-interferon test and CCT was 93.41% (78/83.5), that detected by the routine skin of foreign country was 62.26%(66/106); and that between the hypersensitivity test of China and foreign country was 92.19% (59/64). It is obvious that the interferon-γ testing and CCT seem to have higher coincidence rate and the specificity of the skin tests used in our country was rather low. Consequently, the use of the comparative cervical skin test should be considered to replace the routinely used shin tests.

Genetic Analysis and Rescue of a Triple-reassortant H3N2 Influenza A Virus Isolated From Swine in Eastern China / 中国病毒学·英文版

One influenza H3N2 virus, A/swine/Shandong/3/2005 (Sw/SD/3/2005), was isolated from pigs with respiratory disease on a farm in eastern China. Genetic analysis revealed that Sw/SD/3/2005 was a triple-reassortant virus with a PB2 gene from human-like HIN1, NS from classical swine H1NI, and the remaining genes from human-like H3N2 virus. These findings further support the concept that swine can serve as reservoir or mixing vessels of influenza virus strains and maintain genetic and antigenic stability of viruses. Furthermore, we have successfully established a reverse genetics system based on eight plasmids and rescued Sw/SD/3/2005 through cell transfection. HI tests and RT-PCR confirmed that the rescued virus maintained the biological properties of the wild type Sw/SD/3/2005. The successful establishment of the reverse genetics system of Sw/SD/3/2005 will enable us to conduct extensive studies of the molecular evolution of H3N2 influenza viruses in swine.

Variations of event-related potentials in senile depression and their dynamic changes after treatment / 中华物理医学与康复杂志

Objective To investigate the features of event-related potentials (ERP) P300, auditory evoked potential(AEP) and brainstem auditory evoked potential(BAEP) in senile depression patients and the dynamic chan-ges before and after treatment of sertruline. Methods P300, AEP and BAEP were recorded in 31 senile depression patients using Chinese WOND 2000C Instrument, and a comparison between the patients and 33 normal controls in terms of these evoked potentials were made. Some of the depression patients treated with oral intake of sertraline were followed electophysiologically after 12 months of treatment. Results Compared with normal controls, senile depres-sion patients showed delay of latency of P300-P3 and BAEP-Ⅲ, decreased amplitude of P300-P3, AEP-P2 and BA-EP-Ⅲ(P <0.05 or 0.01). The 12-month follow-up measures of ERP showed significant improvement in terms of la-tency and amplitude of P3/P300,AEP-P2 and BAEP-Ⅲ after treatment of sertraline. Conclusion Senile depres-sion patients showed abnormality on several ERP indexes (such as P3/P300, AEP-P2 and BAEP-Ⅲ), and these in-dexes might provide important evidences to monitor the effect of medicine.