A versatile bioreactor/fermenter system for 'omics' research on diverse aspects of microbial physiology

这项拟议的研究涵盖微生物生理学的多个领域。单细胞微生物，如细菌和酵母，必须迅速适应其直接环境的变化。这种适应能力取决于它们不断感知多种环境线索的能力(如温度、营养状况、氧气供应、酸碱度的波动，以及其他微生物产生的小分子的存在)。细菌可以使用可扩散的小分子作为化学信号，报告细菌种群(自身和竞争对手)的密度。这些信息可以用来改变微生物的适应性反应，这样它们就可以制造出可能适合那个环境的新产品。例如，在高细胞密度下，细菌可能会通过产生毒素或酶来攻击宿主植物、动物或人类，从而变得更具毒性。同样，一些微生物可以制造抗生素，杀死他们的竞争对手，使他们能够更有效地殖民或保护利基。微生物必须对不同的环境压力做出反应--它们通常必须迅速做出反应，以此作为“生死攸关”的反应。在微生物的基因组序列中，多达30%-40%的基因没有可预测的生物学功能，因此努力阐明这些未知的基因实际上对微生物有什么作用是很重要的。酵母细胞是这类研究的优秀实验工具，因为它们的基因组(遗传物质)序列是已知的，而且它们很容易在实验室中培养。类似地，细菌很容易在实验室条件下在生长介质中培养，其成分很容易控制和定义。因此，使用细菌和酵母作为实验工具，有可能试图了解微生物生理学和新陈代谢的许多不同方面--特别是微生物如何适应环境压力，如营养波动、细胞间化学信号和抗生素生产。为了以受控的方式研究这些事件，至关重要的是要有允许微生物以完全可控的方式重复生长的仪器，使实验者有机会确定微生物的营养、其生长速度和所有其他环境参数，如温度和pH。实现这种可重复性的唯一方法是在允许完全生长控制的发酵罐(生物反应器)中培养微生物。只有这样，才能对微生物的遗传学、生物化学、生理学和新陈代谢进行实验，以产生稳健和可重复的结果，从这些结果中可以推断微生物的生物学如何决定它们对环境的反应。因此，这项提议的目的是为一个简单而灵活的发酵罐系统争取资金，生物化学系中的五个(至少)不同的研究小组可以使用这个系统，他们正在研究微生物生物学中的一系列问题。

The proposed research covers multiple areas of microbial physiology. Single celled microbes such as bacteria and yeasts have to adapt rapidly to changes in their immediate environments. This adaptation capacity depends on their ability to constantly sense a multiplicity of environmental cues (such as temperature, nutritional status, oxygen availability, fluctuations in acidity and alkalinity, and the presence of small molecules that are made by other microbes). Bacteria can use small diffusible molecules as chemical signals reporting the density of bacterial populations (self and competitors). This information can be used to change the adaptive responses of the microbes such that they make new products that might be appropriate to that environment. For example, at high cell density bacteria may become more virulent by making toxins or enzymes that attack their host plants, animals or man. Similary, some microbes can make antibiotics that can kill their competitors and allow them to colonise or defend niches more effectively. Microbes have to respond to diverse environmental stresses - and they often have to do this rapidly as a 'life or death' response. In the genome sequences of microbes, as much as 30-40% of the genes have no predictable biological function so it is important to try to elucidate what these 'unknown' genes actually do for the microbe. Yeast cells are excellent experimental tools for such studies because their genome (genetic material) sequence is known and they are easily grown in the laboratory. Similarly, bacteria are easy to cultivate in laboratory conditions in growth media the composition of which can be easily controlled and defined. Thus, using bacteria and yeast as experimental tools, it is possible to try to understand many different aspects of microbial physiology and metabolism - in particular, how microbes adapt to environmental stresses such as nutritional fluctuations, intercellular chemical signalling and antibiotic production. To study these events in a controlled way it is essential to have apparatus that allows the reproducible growth of microbes in a totally controllable fashion, allowing the experimentalist the opportunity to define the nutrition of the microbe, its growth rate and all other environmenal parameters such as temperature and pH. The only way to achieve this reproducibly is to grow the microbes in a fermenter (bioreactor) that allows total growth control. Only then can experiments be done on the genetics, biochemistry, physiology and metabolism of the microbes to generate robust and reproducible results from which it is possible to deduce how the biology of microbes dictates their responses to their environment. This proposal, therefore, is aimed at securing funds for a simple and flexible fermenter system that can be accessed by five (at least) different research groups in the Department of Biochemistry who are working on a range of problems in the biology of microbes.