Saccharomyces cerevisiaeのセントロメア近傍における遺伝子発現抑制

Saccharomyces cerevisiaeにおいて第III番染色体にPGK-lacZ遺伝子を挿入した場合,その発現量は染色体上の位置で異なり位置効果を示す。発現量はCEN3配列の両側でCEN3配列から数百bpの部位で低かった。それら両部位で,PGK-lacZ遺伝子の転写がCEN3配列からテロメアに向かう方向に挿入した場合の発現量が逆方向の場合よりも低くなり,CEN3配列が発現抑制に働く可能性が示唆された。それら2部位に挟まれた領域で発現抑制に働く領域を限定した結果,CEN3配列が抑制に働いた。さらに,第IV番染色体と第V番染色体のセントロメア近傍でもPGK-lacZ遺伝子の発現量は低下した。これらの結果から,セントロメア配列が遺伝子発現を抑制することが分かった。There is a possibility of many kinds of chromosomal position effects on gene expression because of chromosomal higher-order structures, nuclear localization of each region of chromosome, and unequal distribution of transcription factors within a nucleus. In our previous study, we have detected chromosomal position effects on the PGK-lacZ gene on chromosome III in Saccharomyces cerevisiae. As one of such position effects, points located near centromere showed significantly lower activity. So, we tried to understand mechanism of position effects near the CEN3 sequence. Points 113 and 114 are located at 0.6 kb from the CEN3 sequence on a left arm and at 0.4 kb on a right arm, respectively. PGK-lacZ genes at those two points showed lower levels of expression. Introduction of the CEN3 sequence (117 bp) near the PGK-lacZ gene on a plasmid conferred lower level of expression on the reporter gene, and introduction of the CEN3-flanking sequence lacking centromere did not. Moreover, expression levels of the PGK-lacZ gene were lower at points located near the centromere of chromosomes V and XV. Therefore, we think that the centromere sequence prevents fully-expression of genes located near the centromere

Electrochemiluminescence Imaging Hydrogen Evolution Reaction on Single Platinum Nanoparticles Using a Bipolar Nanoelectrode Array

本文制备了嵌于多孔阳极氧化铝（AAO）膜中直径为200 nm,间距为450 nm的高密度（5.7 × 108 cm-2）的金纳米电极阵列,纳米电极分布规则,尺寸高度均一。我们将该金纳米电极阵列作为双极电极阵列,可将电极一侧的电化学法拉第信号在另一侧电极上转化成电致化学发光（ECL）信号,从而实现对单个铂纳米颗粒上氢气析出反应（HER）进行亚微米空间分辨率的电化学成像。本文介绍的方法为高空间分辨率成像电催化材料、能源材料以及细胞过程的局部电化学活性提供了一个良好的平台。A high-density (5.7 × 108 cm-2) nanoelectrode array with the electrode diameter of 200 nm and the interelectrode distance of 450 nm were fabricated. The nanoelectrode array consisted of gold nanowires embedded in a porous anodic aluminum oxide (AAO) matrix, having regular nanoelectrode distribution and highly uniform nanoelectrode size. The gold nanoelectrode array was used as a closed bipolar nanoelectrode array combined with electrochemiluminescence (ECL) method to map the electrocatalytic activity of platinum nanoparticles toward hydrogen evolution reaction (HER) by modifying the catalysts on single nanoelectrodes. Results show that HER on single bipolar nanoelectrodes could be imaged with the sub-micrometer spatial resolution. The present approach offers a platform to image local electrochemical activity of electrocatalytic materials, energy materials and cellular processes with high spatial resolution.通讯作者:夏兴华E-mail:[email protected]:Xing-HuaXiaE-mail:[email protected]生命分析化学国家重点实验室,南京大学化学化工学院,江苏 南京State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering,Nanjing University, Nanjing 210023, Jiangsu Chin

Association between the presence of bacteria in prostate tissue and histopathology in biopsies from men not complaining of lower urinary tract symptoms

Objective: To investigate the presence of bacteria in prostate tissue, and relationships between the bacteria and histopathological findings. Methods: Samples were collected from prostate biopsy patients with no obvious lower urinary tract symptoms (LUTS). Detection and identification of bacterial species in the prostate tissues were performed with PCR for 16SrDNA and DNA sequencing. Histopathology was also evaluated. LUTS and lower urinary tract function were assessed by questionnaires, uroflowmetry, and ultrasonography. Results: DNA was extracted from 97 prostate biopsies, with 5 bacterial species detected among samples from 7 patients (7.2%). The stroma-to-gland ratio in the prostate tissues from patients with bacteria was lower than in those without bacteria (p < 0.01). Glandular epithelial hyperplasia was also identified in the prostates harboring bacteria. International Prostate Symptom Score (IPSS), IPSS-quality of life (IPSS-QOL), Overactive Bladder Symptom Score (OABSS), maximum flow rate, urine volume by uroflowmetry, and post-voided residual urine were not significantly different when comparing patients with and without bacteria in their prostate samples. Conclusions: The present study demonstrated that 7.2% of men without obvious LUTS had bacteria in their prostate tissues. The presence of such bacteria might induce glandular hyperplasia and contribute to pathological changes in the early stages of benign prostate enlargement before affecting LUTS