Detection of plasmid-mediated IMP-1 metallo-β-lactamase and quinolone resistance determinants in an ertapenem-resistant Enterobacter cloacae isolate

Objective  To investigate the mechanism of carbapenem resistance and the occurrence of plasmid-mediated quinolone resistance determinants qnr and aac(6′)-Ib-cr in a clinical isolate of Enterobacter cloacae. Methods  An ertapenem-resistant E. cloacae ZY106, which was isolated from liquor puris of a female gastric cancer patient in a Chinese hospital, was investigated. Antibiotic susceptibilities were determined by agar dilution method. Conjugation experiments, isoelectric focusing, polymerase chain reaction (PCR), and DNA sequence analyses of plasmid-mediated carbapenemases and quinolone resistance determinants were preformed to confirm the genotype. Outer membrane proteins (OMPs) were examined by urea-sodium dodecyl sulfatepolyacrylamide gel electrophoresis (Urea-SDS-PAGE). Results  Minimum inhibitory concentrations (MICs) of imipenem, meropenem, and ertapenem for ZY106 were 2, 4, and 16 μg/ml, respectively. Conjugation studies with Escherichia coli resulted in the transfer of significantly reduced carbapenem susceptibility. ZY106 produced IMP-1 metallo-β-lactamase and CTX-M-3 extended-spectrum β-lactamase, and E. coli transconjugant produced IMP-1. Plasmid-mediated quinolone resistance determinant qnrS1 was detected in ZY106. Transfer of the qnrS1-encoding-plasmid into E. coli by conjugation resulted in intermediate resistance to ciprofloxacin in E. coli transconjugant. Urea-SDS-PAGE analysis of OMPs showed that ZY106 lacked an OMP of approximately 38 kDa. Conclusion  It is the first IMP-1-producing Enterobacteriaceae in China and the first report of a clinical isolate that harbors both blaIMP and qnrS genes as well. The blaIMP-1, blaCTX-M-3, and qnrS1 are encoded at three different plasmids. IMP-1 combined with the loss of an OMP possibly resulted in ertapenem resistance and reduced imipenem and meropenem susceptibility in E. cloacae.      

导电聚苯胺薄膜的电磁学性能及其屏蔽特性

利用四探针测试法分析了导电聚苯胺(PANI-CSA)薄膜的电导率及其屏蔽特性,发现随着薄膜的厚度从4～40μm变化,导电聚苯胺薄膜的室温电导率在12～25S/cm范围内变化.并测试和分析了导电聚苯胺薄膜的屏蔽特性与薄膜厚度的关系,得到了导电聚合物PANI-CSA薄膜的电磁屏蔽效能在一定厚度范围内与理论值是一致的结论.     

Amniotic membrane transplantation for porous sphere orbital implant exposure

Objective： This study is aimed at describing the clinical outcome of amniotic membrane transplantation for exposure of porous sphere implants. Methods： A retrospective review of consecutive cases of porous sphere orbital implant exposure was carried out. Eight cases were presented between May 2004 and Oct. 2006 （5 males, 3 females; mean age 44.5 years）. Six had enucleation and two had evisceration. Exposure occurred in two primary and six secondary. Orbital implant diameter was 22 mm in seven cases and 20 mm in one case. Six patients are with hydroxyapatite and two with high-density porous polyethylene （Medpor） orbital implants. The mean time from implantation to exposure was 1.1 months （range 0.8-2 months）. All patients required surgical intervention. Results： The time of follow-up ranged from 3.0 to 28.0 months （mean 16.5 months）. Amniotic membrane grafting successfully closed the defect without re-exposure in all of these patients. The grafts were left bare with a mean time to conjunctiva of about 1 month （range 0.8-1.5 months）. Conclusion： Exposed porous sphere implants were treated successfully with amniotic membrane graft in all of patients. The graft is easy to harvest. This technique is useful, dose not lead to prolonged socket inflammation and infection, and it is valuable application extensively.     

Adenoma of nonpigmented epithelium in ciliary body： literature review and case report

Adenomas of the nonpigmented ciliary epithelium （NPCE） are often clinically indistinguishable from amelanotic malignant melanomas of the ciliary body or metastatic carcinomas. This paper reports a case study of a distinctive variant of adenoma of the NPCE, which clinically appears as epiretinal membrane in the macular region. Histopathologic studies have revealed this is an adenoma of the NPCE. Identification of this clinic feature is important because it will miss the diagnosis of the adenoma of the NPCE. In this case study, B-scan ultrasonography as well as computerized tomography （CT） has been used to provide help in diagnosing the ciliary body tumor. Because of their anterior location in the ciliary body, partial lamellar sclerouvectomy is an effective method of treatment.     

Effects of the crude extract of Polygala tenuifolia Willd on human sperm in vitro

The aim of the present study is to analyze sperm membrane changes and the spermicidal effect in treatment with the crude extract from Polygala tenuifolia Willd (PTW) in vitro. The root of PTW was extracted in distilled water. Normal human spermatozoa were used to assess the spermicidal activity (Sander-Cramer assay) of the extract from the PTW root. The hypo-osmotic swelling (HOS) test and the eosin Y (EY) staining were used to detect the integrity of sperm membrane and vitality. The sperm chromatin dispersion (SCD) test was performed to determine sperm DNA integrity. N-9 was used as a reference standard and semen added to physiological saline was used as the control. Semen samples were donated by 42 healthy fertile men. The crude extract from the root of PTW could immobilize and kill 100% spermatozoa within 20 s in vitro at the concentrations of 20.0 and 10.0 mg/ml; at the concentration of 5.0 mg/ml, spermatozoa were immobilized in (39.5±3.2) s. In the groups of the crude extract from the root of PTW and N-9 solution, the rate of the normal HOS (tails swollen) and the white head (unstained) was 0%, and the rate of the abnormal HOS (tails unswollen) and red head (stained) was 100%. Sperm DNA fragmentation showed no change in exposure to the crude extract from the root of PTW and N-9 solution. The sperm revival test did not show any spermatozoa that recovered their motilities. The rapid spermicidal activity of the crude extract from the root of PTW in vitro may occur by the disruption of the sperm membrane integrity.     

一种重要的光合膜蛋白——菠菜主要捕光复合物的晶体结构

由生物物理研究所主持,植物研究所参加完成的"菠菜主要捕光复合物的晶体结构"研究成果以Article的方式发表在2004年3月18日出版的Nature上,该晶体结构图被选作本期杂志的封面图案.本文介绍了该项成果的研究背景、意义、主要创新点及方法.     

人工皮二胡与蟒皮二胡声学特性的对比研究

从音乐声学的角度,通过响度、动态范围、谐音时域能量、非谐波成分、频响曲线等方面,对人工皮二胡与蟒皮二胡的音强与音色进行对比研究。     

改变芯液组成控制氧化铝中空纤维膜微结构

采用相分离成型/烧结技术制备了多种结构的氧化铝(Al2O3)中空纤维膜(HFA)。考察了内凝固剂(芯液)的组成与氧化铝中空纤维膜结构之间的规律性。利用SEM观察HFA的微观结构。结果表明:改变内凝固剂的组成能够控制氧化铝中空纤维膜的微观结构。内凝固剂中水含量由100%降低到10%,HFA的指状孔分布位置和长度都发生了变化。当内凝固剂为纯水时,指状孔只分布在HFA的内侧;内凝固剂中水含量低至30%时,指状孔延长形成贯通整个横截面的通孔。     

肺炎衣原体膜表面蛋白重组质粒的构建

目的 构建表达肺炎衣原体膜表面蛋白(OMP)的重组质粒，并在火肠杆菌中表达获得基因重组蛋白．方法用高保真PCR方法从肺炎衣原体扩增OMP片段．双酶切后插入原核表达质粒pQE-30，在大肠杆菌M15中表达，结果重组质粒经双酶切鉴定与目的基因长度相符；各表达蛋白经SDS-PAGE分析，相对分子量与文献相符．结论该重组质粒可用于核酸疫苗的备选质粒，基因重组菌表达的融合蛋白有可能作为有效抗原用于肺炎衣原体检测试剂盒的制备。     

W/O型微乳液表面张力、液滴半径等之间的关系

由W(？)O型微乳液的生成给出一个简单处理模型,经几个步骤的数字处理得出γ=-常数×1/a2g((？))的γ与 a.(？)的 关系式,因此可解释某些相平衡.