Artwohl J E, Savage D C
Appl Environ Microbiol. 1979 Apr;37(4):697-703. doi: 10.1128/aem.37.4.697-703.1979.
Torulopsis pintolopesii is an indigenous yeast that colonizes the secreting epithelia in the stomachs of mice and rats. A wild-type strain of this microbe was isolated and identified. To attempt to learn characteristics of the yeast that are advantageous to it in colonizing its natural habitat in vivo, we examined some aspects of its nutrition and energy-yielding metabolism and some environmental conditions that influence its growth in vitro. The yeast appeared to be limited in the compounds it can utilize as carbon and nitrogen sources. It grew best at 37 degrees C and did not grow at 23 or 43 degrees C. It grew optimally at neutral pH but could grow aerobically at pH values as low as 2.0 and anaerobically at pH values as low as 3.4. As assessed by measurements of growth rates and yield coefficients, it grew better aerobically than anaerobically. When grown aerobically, it had a cyanide-sensitive system for taking up O(2) and tested positively for cytochrome c oxidase activity. A petite mutant strain isolated from the wild-type strain had a growth rate and yield coefficient when incubated aerobically that were essentially the same as those of the wild-type parent grown anaerobically. Likewise similar to the wild-type parent grown anaerobically, the petite strain, though incubated aerobically, did not take up O(2). Yeast-free mice associated with either the wild-type or the petite mutant strain were colonized at essentially the same rates and to similar final population levels by both strains. The yeast's capacity to respire may be of little advantage to it in its natural environment. By contrast, its abilities to grow best at 37 degrees C and to grow at low pH values are undoubtedly advantageous characteristics in this respect. The limitations in its carbon and nitrogen nutrition are difficult to evaluate as ecological factors in its colonization of the natural habitat.
平托洛佩斯假丝酵母是一种本土酵母，可定殖于小鼠和大鼠胃中的分泌上皮。分离并鉴定了该微生物的野生型菌株。为了试图了解这种酵母在体内定殖于其自然栖息地时所具有的有利特征，我们研究了其营养和能量产生代谢的一些方面以及一些影响其体外生长的环境条件。这种酵母在可作为碳源和氮源利用的化合物方面似乎受到限制。它在37℃时生长最佳，在23℃或43℃时不生长。它在中性pH值下生长最佳，但在低至2.0的pH值下可进行有氧生长，在低至3.4的pH值下可进行无氧生长。通过生长速率和产量系数的测量评估，它有氧生长比无氧生长更好。有氧生长时，它有一个对氰化物敏感的摄取O₂系统，并且细胞色素c氧化酶活性检测呈阳性。从野生型菌株分离出的一个小菌落突变株在有氧培养时的生长速率和产量系数与野生型亲本无氧培养时基本相同。同样类似于无氧培养的野生型亲本，小菌落菌株虽然是有氧培养，但不摄取O₂。与野生型或小菌落突变株相关的无菌小鼠被这两种菌株定殖的速率基本相同，最终种群水平也相似。这种酵母的呼吸能力在其自然环境中可能对它没有什么优势。相比之下，它在37℃时生长最佳以及在低pH值下生长的能力在这方面无疑是有利特征。其碳和氮营养的限制作为其在自然栖息地定殖的生态因素很难评估。
