The plasticity region of Helicobacter pylori strain J99 is a large chromosomal segment containing 33 strain-specific open reading frames (ORFs) with characteristics of a pathogenicity island. To study the diversity of the plasticity region, 22 probes corresponding to 20 ORFs inside the plasticity region and two ORFs on its boundaries were hybridized to genomic DNA isolated from clinical strains of H. pylori from patients with gastritis or gastric adenocarcinoma. Highly variable hybridization patterns were observed. The majority of the clinical strains presented a hybridization profile similar to that of J99; thus, these ORFs are not J99 strain specific. No association was found between a particular hybridization pattern and the clinical origin of the strain. Nevertheless, two single ORFs (JHP940 and JHP947) were more likely to be found in gastric cancer strains. They may be new pathogenicity markers. An in vitro expression study of these ORFs was also performed for the J99 strain, under different conditions. Thirteen ORFs were consistently expressed, six were consistently shut off, and three were expressed differentially. Most of the constitutionally expressed genes were located on the 3' part of the plasticity region. Our results show that the plasticity region, rather than being considered a pathogenicity island per se, should be considered a genomic island, which represents a large fragment of foreign DNA integrated into the genome and not necessarily implicated in the pathogenic capacity of the strain.

译文

幽门螺杆菌J99菌株的可塑性区域是一个大的染色体片段,包含33个具有致病性岛特征的菌株特异性开放阅读框 (orf)。为了研究可塑性区域的多样性,将对应于可塑性区域内20个orf的22个探针及其边界上的两个orf与从胃炎或胃腺癌患者的临床幽门螺杆菌菌株中分离的基因组DNA杂交。观察到高度可变的杂交模式。大多数临床菌株的杂交特征与J99相似; 因此,这些orf不是J99菌株特异性的。在特定的杂交模式与菌株的临床起源之间未发现关联。然而,在胃癌菌株中更可能发现两个单一orf (JHP940和JHP947)。它们可能是新的致病性标志物。还在不同条件下对J99菌株进行了这些orf的体外表达研究。持续表达13个orf,持续关闭6个orf,差异表达3个orf。大多数组成表达的基因位于可塑性区域的3' 部分。我们的结果表明,可塑性区域,而不是被认为是致病岛本身,应该被认为是基因组岛,它代表整合到基因组中的大量外源DNA片段,不一定与菌株的致病能力有关。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录