Bukholm G, Tannaes T, Nedenskov P, Esbensen Y, Grav H J, Hovig T, Ariansen S, Guldvog I
Institute of Medical Microbiology, University of Oslo, Norway.
Scand J Gastroenterol. 1997 May;32(5):445-54. doi: 10.3109/00365529709025079.
Differences in expression of disease after infection with Helicobacter pylori have so far been connected with host factors and bacterial interstrain variation. In this study, spontaneous and ecology-mediated intrastrain variation was examined.
Four clinical isolates of H. pylori were shown to give rise to two colony forms. Bacterial morphology was examined by electron microscopy. Bacterial fractions were examined for proteins using ion exchange chromatography and SDS-PAGE; for lipids using thin-layer chromatography, lipid anion-exchange chromatography, column chromatography on silica gel, 31P-NMR, gas chromatography and mass spectrometry. Bacterial in vitro invasiveness and adhesiveness were examined in two different systems, and urease and VacA toxin were assayed by Western blot analysis.
H. pylori was shown to give rise to two colony forms: at normal pH the population was dominated by L colonies. One strain was chosen for further studies. Bacteria from L colonies retained VacA toxin and urease, did not invade or adhere to epithelial cells, and contained normal quantities of phosphatidylethanolamine. In a small frequency, spontaneous S colonies were formed. Bacteria from these colonies released VacA and urease, adhered to and invaded epithelial cells and contained increased amounts of lysophosphatidyl ethanolamine and phosphatidyl serine. After addition of HCl to the culture medium (pH6), almost only S colonies were formed. The results demonstrate that environmental factors, such as HCl, can change the bacterial cell wall, and thereby enhance expression of virulence factors of H. pylori in vitro. A similar in vivo variation would have implications for our understanding of the interaction between HCl secretion in the gastric mucosa and H. pylori in the development of peptic ulcer disease.
迄今为止，幽门螺杆菌感染后疾病表达的差异与宿主因素和细菌菌株间变异有关。在本研究中，对自发的和生态介导的菌株内变异进行了检测。
4株幽门螺杆菌临床分离株显示可产生两种菌落形态。通过电子显微镜检查细菌形态。使用离子交换色谱法和SDS-PAGE检测细菌组分中的蛋白质；使用薄层色谱法、脂质阴离子交换色谱法、硅胶柱色谱法、31P-NMR、气相色谱法和质谱法检测脂质。在两种不同系统中检测细菌的体外侵袭性和黏附性，并通过蛋白质印迹分析测定脲酶和空泡毒素（VacA）。
幽门螺杆菌显示可产生两种菌落形态：在正常pH值下，群体以L菌落为主。选择其中一株进行进一步研究。来自L菌落的细菌保留了VacA毒素和脲酶，不侵袭或黏附上皮细胞，且含有正常量的磷脂酰乙醇胺。偶尔会形成自发的S菌落。来自这些菌落的细菌释放VacA和脲酶，黏附并侵袭上皮细胞，且含有增加量的溶血磷脂酰乙醇胺和磷脂酰丝氨酸。向培养基中添加HCl（pH6）后，几乎只形成S菌落。结果表明，诸如HCl等环境因素可改变细菌细胞壁，从而在体外增强幽门螺杆菌毒力因子的表达。类似的体内变异将对我们理解胃黏膜中HCl分泌与幽门螺杆菌在消化性溃疡疾病发生过程中的相互作用具有启示意义。
