Pope L M, Cole G T
Scan Electron Microsc. 1981(Pt 3):73-80.
In our earlier investigations it has been shown that the gastrointestinal (GI) tract of the infant mouse (4-5 days old) can be colonized following a single intragastric challenge with Candida albicans. This makes it possible to investigate the sequence of events which occur during colonization of the GI tract by this opportunistic yeast. Two strains of C. albicans, CA 30 and NS 33, which were shown in earlier studies to differ markedly in their ability to persist in the GI tract were examined. The SEM was used to reveal the location of the yeast and their structural association with the surface of tissues of the gut at early times after intragastric inoculation. Animals were sacrificed after challenge, the GI tract was removed from each mouse and subdivided into the stomach, upper intestine, mid-intestine, ileum, cecum and large bowel. The number of colony forming units was determined by homogenizing these segments and plating them out on sabouraud's dextrose agar. The microenvironment of each segment was preserved by freezing samples in liquid nitrogen prior to processing for the SEM. The distribution and level of counts of the strains studied in the GI tract were comparable during the three week period. Both strains of C. albicans associated with the secreting epithelium and the keratinized epithelium of the stomach. Yeast also associated with the mucus layer and the epithelial surface throughout the GI tract. Those yeast adhering to the epithelial surfaces of the GI tract were frequently covered by a layer of mucus which may aid in colonization.
在我们早期的研究中已经表明，用白色念珠菌对4 - 5日龄的幼鼠进行单次胃内攻击后，其胃肠道能够被定殖。这使得研究这种机会性酵母在胃肠道定殖过程中发生的一系列事件成为可能。研究了两株白色念珠菌CA 30和NS 33，它们在早期研究中显示出在胃肠道中持续存在的能力有显著差异。扫描电子显微镜（SEM）用于揭示胃内接种后早期酵母的位置及其与肠道组织表面的结构关联。攻击后处死动物，从每只小鼠身上取出胃肠道并细分为胃、上段小肠、中段小肠、回肠、盲肠和大肠。通过将这些节段匀浆并接种在沙氏葡萄糖琼脂上，来确定菌落形成单位的数量。在进行扫描电子显微镜处理之前，通过将样品在液氮中冷冻来保存每个节段的微环境。在三周时间内，所研究的菌株在胃肠道中的分布和计数水平相当。两株白色念珠菌均与胃的分泌上皮和角质化上皮相关联。酵母还与整个胃肠道的黏液层和上皮表面相关联。那些附着在胃肠道上皮表面的酵母经常被一层黏液覆盖，这可能有助于定殖。
