Levofloxacin susceptibility testing for Helicobacter pylori in China: comparison of E-test and disk diffusion method

Background: The aims of this study were to compare disk diffusion with E‐test method for levofloxacin susceptibility testing of Helicobacter pylori and standardized breakpoints for disk diffusion as a stable and reliable method for determining qualitative levofloxacin susceptibility. Materials and Methods: We determined the levofloxacin susceptibility of 45 H. pylori strains isolated from Chinese patients by the E‐test method. Disk diffusion was evaluated as an alternative method to determine susceptibility and compared with the E‐test results by linear regression analysis. Results: The minimum inhibitory concentration (MIC) values tested by E‐test method ranged from 0.047 to 32 μg/mL. Resistance to levofloxacin was detected in 16 (35.6%) isolates. The levofloxacin disk zone sizes obtained by disk diffusion method correlated well (r² = .877) with the MICs obtained by E‐test method. As a consequence of regression analysis, isolates with inhibition diameters <12 mm were considered resistant to levofloxacin. There was 100% agreement between the two methods for levofloxacin, applying the regression‐based breakpoints. Conclusions: The disk diffusion method is equivalent to the E‐test method for testing levofloxacin susceptibility of H. pylori strains; it is more practical and inexpensive, and it is suitable for the analysis of a small number of isolates compared with the E‐test method.     

Non-invasive limb ischemic pre-conditioning reduces oxidative stress and attenuates myocardium ischemia-reperfusion injury in diabetic rats

This study was to explore whether repeated non-invasive limb ischemic pre-conditioning (NLIP) can confer an equivalent cardioprotection against myocardial ischemia-reperfusion (I/R) injury in acute diabetic rats to the extent of conventional myocardial ischemic pre-conditioning (MIP) and whether or not the delayed protection of NLIP is mediated by reducing myocardial oxidative stress after ischemia-reperfusion. Streptozotocin-induced diabetic rats were randomized to four groups: Sham group, the I/R group, the MIP group and the NLIP group. Compared with the I/R group, both the NLIP and MIP groups showed an amelioration of ventricular arrhythmia, reduced myocardial infarct size, increased activities of total superoxide dismutase (SOD), manganese-SOD and glutathione peroxidase, increased expression of manganese-SOD mRNA and decreased xanthine oxidase activity and malondialdehyde concentration (All p < 0.05 vs I/R group). It is concluded that non-invasive limb ischemic pre-conditioning reduces oxidative stress and attenuates myocardium ischemia-reperfusion injury in diabetic rats.     

电转化法构建变形链球菌UA159 comD缺陷菌株

目的构建变形链球菌UAl59密度感应相关的comD基因缺陷菌株,为进一步研究该基因功能做准备。方法根据同源重组原理,利用变形链球菌UAl59comD基因同源重组DNA片段,采用电击转化方法获取转化菌落,通过形态学观察、生化特性检测、PCR及测序、RT-PCR对缺陷菌进行鉴定。结果在含有红霉素（10μg/mL）的琼脂平板上出现转化菌落,鉴定结果均显示转化菌为comD缺陷菌。结论成功构建了变形链球菌UA159comD基因缺陷菌株。     

Upregulation of p21-activated Kinase 6 in rat brain cortex after traumatic brain injury

p21-activated Kinase 6 (PAK6) is a serine/threonine kinase belonging to the p21-activated kinase (PAK) family. PAK kinases are well-known regulators of a wide variety of cellular functions, including regulation of cytoskeleton rearrangement, cell survival, apoptosis and the mitogen-activated protein kinase signaling pathway. To elucidate the expressions and possible functions of PAK6 in central nervous system (CNS) lesion and repair, we performed a traumatic brain injury (TBI) model in adult rats. Western blot analysis revealed that PAK6 level significantly increased at day 3 after damage, and then declined during the following days. Besides, double immunofluorescence staining showed PAK6 was primarily expressed in the neurons and a few of glial cells in the normal group. While after injury, the expression of PAK6 was increased significantly in the astrocytes and neurons, and the astrocytes had largely proliferated. We also examined the expression of proliferating cell nuclear antigen (PCNA) whose change was correlated with the expression of PAK6. Importantly, double immunofluorescence staining revealed that cell proliferation evaluated by PCNA appeared in many PAK6-expressing cells at day 3 after injury. In addition, injury-induced expression of PAK6 was co-labeled by active caspase-3 during neuronal apoptosis after injury. Collectively, we hypothesized PAK6 may play important roles in CNS pathophysiology after TBI and further research is needed to have a good understanding of its function and mechanism.     

Computational identification of protein-protein interactions in rice based on the predicted rice interactome network

Plant protein-protein interaction networks have not been identified by large-scale experiments. In order to better understand the protein interactions in rice, the Predicted Rice Interactome Network (PRIN; http://bis.zju.edu.cn/prin/) presented 76,585 predicted interactions involving 5,049 rice proteins. After mapping genomic features of rice (GO annotation, subcellular localization prediction, and gene expression), we found that a well-annotated and biologically significant network is rich enough to capture many significant functional linkages within higher-order biological systems, such as pathways and biological processes. Furthermore, we took MADS-box domain-containing proteins and circadian rhythm signaling pathways as examples to demonstrate that functional protein complexes and biological pathways could be effectively expanded in our predicted network. The expanded molecular network in PRIN has considerably improved the capability of these analyses to integrate existing knowledge and provide novel insights into the function and coordination of genes and gene networks.     

花梨木叶中鹰嘴豆芽素A的提取工艺研究

以花梨木的可再生资源—叶子为原料,利用微波辅助酶提取技术进行提取,在单因素试验的基础上对提取条件进行了考察,根据BBD(Box-Behnken design)实验设计原理,采用3因素3水平的响应面分析法,以花梨木叶子中主要异黄酮鹰嘴豆芽素A(biochanin A)为指标,对提取过程进行优化,得到最佳工艺参数为:提取时间15 min,微波辐射功率300 W,提取温度34℃,pH值5.2,酶的加入量3.5 mg.g-1。在最佳提取条件下,鹰嘴豆芽素A的提取率可达1.579 mg.g-1。     

Molecular cloning, characterization and association analysis of the promoter region of the bovine CDK6 gene

Cyclin-dependent kinase 6 (CDK6) is a key element of D-type cyclin holoenzymes. It is involved in the regulation of the G1-phase of the cell cycle and is considered to be an important candidate gene for selection of body measurement traits through marker-assisted selection. We cloned the promoter sequence of this gene in bovines and found it to share high similarity with that of the human CDK6 promoter. A 2271-bp sequence upstream of the start codon in the bovine CDK6 5'-flanking sequence is rich in GC; it lacks consensus TATA or CAAT box, but it contains several MZF1 binding sites. Other potential cis-regulatory elements were found in the 5'-flanking region, including CdxA, SRY, p300, GATA-1, and deltaE. Allele frequencies were also analyzed in various cattle breeds (Qinchuan, Qinchuan improvement steers, Nanyang, Jiaxian red, Xia'nan, Luxi, Simmental and Luxi crossbred steers, and Xuelong) and association with a selected single nucleotide polymorphism (SNP) was calculated. The T-1075C SNP in the promoter was found to be significantly associated with body length and heart girth. This SNP marker was found to be significantly associated with body length and the heart girth in 737 individuals. We conclude that this SNP of the CDK6 gene has potential as a genetic marker for important body traits in bovine reproduction and breeding.     

Serum metabolic profiling and features of papillary thyroid carcinoma and nodular goiter

Thyroid carcinoma is a common endocrine malignancy worldwide, accounting for approximately 1% of all diagnosed cancers and about 91.5% of the malignancies of head and neck. However, differentiating malignant thyroid nodules from benign ones remains a diagnostic challenge. Thus, novel molecular markers that enable non-invasive diagnostics for malignant thyroid nodules are urgently needed. In the present study, a metabonomic investigation based on liquid chromatography-LTQ Orbitrap mass spectrometry was employed for serum metabolic profiling of 30 cases of papillary thyroid carcinomas (PTC), 80 cases of nodular goiters (benign thyroid nodules) and 30 cases of healthy controls. According to the results of multivariate statistical data analysis, the significantly changed metabolites among these three groups were defined. It was found that most of these metabolites decreased in the sera of both malignant and benign thyroid cases due to the increased metabolic rate, which is in accordance with clinical features. The major metabolic differences between benign and malignant nodules occurred in lipid metabolism. Especially, the content of 3-hydroxybutyric acid, an intermediate product of fatty acid metabolism, was much higher in the PTC group than that in the nodule goiter and control groups, indicating its potential as a diagnostic marker for PTC and nodular goiters. These results show that the serum metabolic profiling method is a powerful tool for distinguishing thyroid carcinoma from nodular goiter and healthy controls.