RUI: Acid and Base Stress in Escherichia Coli

凯尼恩学院（Kenyon College）的Joan Slonczewski博士获得了一笔赠款，用于研究细菌大肠杆菌（Escherichia coli）中的酸碱胁迫，并培训微生物学研究方面的本科生。细菌制造不同的蛋白质，以帮助它们在pH值的极端变化中生存，无论是在自然环境中还是在人体内。对于这个项目（MCB-9982437的延续），已经开发了ph调节蛋白的模型。该模型预测，在酸性环境中的生长导致大肠杆菌将其食物转化为碱性发酵产物，反之亦然。该模型将使用二维凝胶电泳进行测试，以观察代谢酶的诱导作用，从而产生不同的最终产物，这些最终产物将通过高效液相色谱法进行鉴定。此外，还将研究各种酸性和碱性终产物对细菌代谢的影响。酸和碱的调节对于细菌在土壤和水生环境中以及在人体肠道中生存是重要的。大肠杆菌作为一种模式生物，其基因组已经被测序，作为一种“嗜中性菌”，一种可以在酸或碱中生长的物种，特别有趣。食品保存的许多机制，如使用弱酸苯甲酸盐和山梨酸盐，取决于pH值；然而，越来越多的食源性病原体具有耐酸性。揭示对pH变化的响应机制将有助于我们更好地了解其对环境的影响，以及pH在食品质量和保鲜中的作用。此外，了解细菌培养物中的pH值和代谢将有助于改善细菌生产的生长条件。凯尼恩学院强调本科教育，学生将参与这个项目的各个方面，因为他们将接受微生物学研究实验的培训。一些本科生已经被吸引到这个项目中来，他们被鼓励从事科学事业。

A grant has been awarded to Dr. Joan Slonczewski of Kenyon College to study acid and base stress in the bacterium, Escherichia coli, and to train undergraduate students in microbiological research. Bacteria make different proteins to help them survive extreme changes in pH, both in natural environments and within the human body. For this project (a continuation of MCB-9982437), a model of pH-regulated proteins has been developed. This model predicts that growth in acid leads E. coli to convert its food into alkaline fermentation products, and vice-versa. This model will be tested using two-dimensional gel electrophoresis to observe induction of metabolic enzymes that lead to different end products, which will, in turn, be identified by using high-performance liquid chromatography. In addition, the effects of various acidic and alkaline end products on bacterial metabolism will be studied. Acid and base regulation are important for bacteria to survive in soil and aquatic environments, as well as in the human intestine. E. coli is particularly interesting as a model organism whose genome has been sequenced, and as a "neutralophile," a species that can grow in either acid or base. Many mechanisms of food preservation, such as the use of weak acids benzoate and sorbate, depend on pH; yet increasingly food-borne pathogens are acid resistant. Revealing the mechanisms of response to pH change will help us to better understand its environmental effects, as well as the role of pH in food quality and preservation. Furthermore, understanding of pH and metabolism in bacterial cultures will contribute to biotechnology by helping improve growth conditions for bacterial production. Kenyon College emphasizes undergraduate education, and students will be involved in every aspect of this project as they are trained to perform research experiments in microbiology. Several undergraduates have already been attracted to work on the project, and they are encouraged to pursue careers in science.