Roles of putative His-to-Asp signaling modules HPT-1 and RRG-2, on viability and sensitivity to osmotic and oxidative stresses in <Emphasis Type="Italic">Neurospora crassa</Emphasis>

Neurospora crassa has a putative histidine phosphotransfer protein (HPT-1) that transfers signals from 11 histidine kinases to two putative response regulators (RRG-1 and RRG-2) in its histidine-to-aspartate phosphorelay system. The hpt-1 gene was successfully disrupted in the os-2 (MAP kinase gene) mutant, but not in the wild-type strain in this study. Crossing the resultant hpt-1; os-2 mutants with the wild-type or os-1 (histidine kinase gene) mutant strains produced no progeny with hpt-1 or os-1; hpt-1 mutation, strongly suggesting that hpt-1 is essential for growth unless downstream OS-2 is inactivated. hpt-1 mutation partially recovered the osmotic sensitivity of os-2 mutants, implying the involvement of yeast Skn7-like RRG-2 in osmoregulation. However, the rrg-2 disruption did not change the osmotic sensitivity of the wild-type strain and the os-2 mutant, suggesting that rrg-2 did not participate in the osmoregulation. Both rrg-2 and os-2 single mutation slightly increased sensitivity to t-butyl hydroperoxide, and rrg-2 and hpt-1 mutations increased the os-2 mutant’s sensitivity. Although OS-1 is considered as a positive regulator of OS-2 MAP kinase, our results suggested that HPT-1 negatively regulated downstream MAP kinase cascade, and that OS-2 and RRG-2 probably participate independently in the oxidative stress response in N. crassa.     

The susceptibility of T5-TG12 of theCFTR gene in chronic bronchitis occurrence in a Chinese population in Jiangsu province,China

Mutations in the cystic fibrosis transmembrane conductance regulator(CFTR) gene have been implicated in the onset of cystic fibrosis and other clinical respiratory disorders.In the present study,we investigated the role of CFTR variations,poly-T,TG-repeats,and M470V in susceptibility to bronchial asthma and chronic bronchitis in a Chinese population in Jiangsu province,China.A total of 72 bronchial asthma patients,68 chronic bronchitis patients,and 117 healthy subjects were included in this study.The Tn-TGm haplotype was sequenced and the CFTR variant M470V was detected using restriction fragment length polymorphism(RFLP).We found that the frequency of T5-TG12-V470 in chronic bronchitis patients was 0.07%,which was notably higher than that in healthy subjects(0.01%) and bronchial asthma patients(0.04%).Thus,the presence of the T5-TG12 haplotype of the CFTR gene is likely to play a role in the development and progression of respiratory conditions,such as chronic bronchitis.     

低氧培养促进大鼠髓核间质干细胞增殖

目的研究低氧培养对大鼠髓核间质干细胞(NPMSCs)增殖的影响。方法分离大鼠尾椎髓核获得NPMSCs并进行体外扩增培养,观察细胞形态,流式细胞仪鉴定细胞免疫表型。取第3代NPMSCs分为常氧组和2%低氧组,分别培养7 d及14 d,观察细胞形态;MTT法检测细胞增殖;流式细胞仪检测细胞活力和RT-q PCR检测低氧诱导因子1α(HIF-1α)、葡萄糖转运蛋白1(GLUT-1)、血管内皮生长因子(VEGF)、沉默信息调节蛋白1(SIRT1)及SIRT6的mRNA表达情况。结果原代NPMSCs细胞早期可形成葵花样细胞集落,传代后细胞增殖明显加快,细胞形态以纺锤形为主。第3代细胞高表达干细胞相关阳性表面抗原分子,低表达干细胞相关阴性表面抗原分子。低氧组细胞形态以多角形为主,细胞更容易聚集成团块,且细胞增殖速度明显加快(P0.05),细胞凋亡率明显下降(P0.05)。低氧组HIF-1α、VEGF、GLUT-1、SIRT1及SIRT6表达量明显高于常氧组(P0.05)。结论 2%O2的低氧环境促进髓核间质干细胞增殖,其机制可能与SIRT1及SIRT6介导的HIF-1α信号通路有关。     

Changes in the infectivity, pyruvate kinase activity, acid phosphatase activity and P-glycoprotein expression in glibenclamide-resistant Leishmania mexicana

We previously demonstrated susceptibility of Leishmania sp. to glibenclamide, a K⁺-ATP transport blocker which interacts with members of the superfamily of adenosine 5′ triphosphate-binding cassette transporters. In order to characterize the molecular differences between a sensitive Leishmania strain, NR(Gs), and an experimentally selected glibenclamide-resistant strain, NR(Gr), specific biochemical and functional parameters have been evaluated both in the wild type and in the resistant strain. Most noteworthy, NR(Gr) exhibit an increased expression of P-glycoprotein and a decreased activity of functional key enzymes such as acid phosphatase, a prominent virulent factor of the parasite, and pyruvate kinase, a key control enzyme for both carbohydrate and protein metabolism. The specific biochemical, metabolic and functional changes observed in the resistant strain correlated with a reduced infectivity of stationary phase NR(Gr) in J774 macrophages and suggested a mechanism to overcome the effect of glibenclamide. Received: 21 January 2000 / Accepted: 1 March 2000     

Comparison of the suppressive effects of soluble CR1 and C5a receptor antagonist in acute arthritis induced in rats by blocking of CD59

We investigated the effects of suppression of complement activation at C3 level and inhibition of C5a on acute synovitis in rats. Acute synovitis was induced in Wistar rats by intra-articular (i.a.) injection into one knee of 0.3 mg of MoAb 6D1 (anti-rat CD59 antibody). In the treatment groups, soluble CR1 (sCR1) or C5a receptor (C5aR) antagonist was administered intra-articularly or intravenously and effects on the course of the acute synovitis were monitored. Synovitis induced by 6D1 was characterized by joint swelling, thickening of synovial tissue, cellular infiltration and deposition of membrane attack complex (MAC) on the synovial surface. Neither inflammatory change nor MAC deposition was found in rats which received an i.a. injection of sCR1 to suppress complement activity in the joint. Intra-articular injection of sCR1 did not reduce plasma complement activity. Intravenous administration of sCR1 suppressed plasma complement activity but had no effect on the course of the arthritis and synovitis with MAC deposition was observed. Neither i.a. nor i.v. injection of C5aR antagonist had any suppressive effects on inflammatory change or MAC deposition in synovium. The data show that inflammatory change induced by 6D1 was mediated by local complement activation and was not accompanied by systemic complement activation. C5a generation was not responsible for the observed inflammation, suggesting that other complement activation products, possibly MAC, mediate the inflammatory change observed in this model of acute synovitis in rats.     

先天性单侧输精管缺如患者CFTR基因突变研究

目的 探讨囊性纤维跨膜转运调节物（ｃｙｓｔｉｃ ｆｉｂｒｏｓｉｓ ｔｒａｎｓｍｅｍｂｒａｎｅ ｃｏｎｄｕｃｔａｎｃｅ ｒｅｇｕｌａｔｏｒ,ＣＦＴＲ）基因在中国人先天性单侧输精管缺如（ｃｏｎｇｅｎｉｔａｌ ｕｎｉｌａｔｅｒａｌ ａｓｅｎｃｅｏｆ ｔｈｅ ｖａｓ ｄｅｆｅｒｅｎｓ,ＣＵＡＶＤ）患者中的突变频率及热点。方法 应用聚合酶反应－单链构象多态（ＰＣＲ－ＳＳＣＰ）、３银染技术及ＰＣＲ产物直接序