Casida L E
Microbiology Program, S-101 Frear Building, Pennsylvania State University, University Park, Pennsylvania 16802.
Appl Environ Microbiol. 1989 Aug;55(8):1857-1859. doi: 10.1128/aem.55.8.1857-1859.1989.
Representatives of several categories of bacteria were added to soil to determine which of them might elicit responses from the soil protozoa. The various categories were nonobligate bacterial predators of bacteria, prey bacteria for these predators, indigenous bacteria that are normally present in high numbers in soil, and non-native bacteria that often find their way in large numbers into soil. The soil was incubated and the responses of the indigenous protozoa were determined by most-probable-number estimations of total numbers of protozoa. Although each soil was incubated with only one species of added bacteria, the protozoan response for the soil was evaluated by using most-probable-number estimations of several species of bacteria. The protozoa did not respond to incubation of the soil with either Cupriavidus necator, a potent bacterial predator, or one of its prey species, Micrococcus luteus. C. necator also had no effect on the protozoa. Therefore, in this case, bacterial and protozoan predators did not interact, except for possible competition for bacterial prey cells. The soil protozoa did not respond to the addition of Arthrobacter globiformis or Bacillus thuringiensis. Therefore, the autochthonous state of Arthrobacter species in soil and the survival of B. thuringiensis were possibly enhanced by the resistance of these species to protozoa. The addition of Bacillus mycoides and Escherichia coli cells caused specific responses by soil protozoa. The protozoa that responded to E. coli did not respond to B. mycoides or any other bacteria, and vice versa. Therefore, addition to soil of a nonsoil bacterium, such as E. coli, did not cause a general increase in numbers of protozoa or in protozoan control of the activities of other bacteria in the soil.
将几类细菌的代表添加到土壤中，以确定它们中哪些可能引发土壤原生动物的反应。这些不同类别包括细菌的非专性捕食性细菌、这些捕食者的猎物细菌、土壤中通常大量存在的本土细菌以及经常大量进入土壤的非本土细菌。将土壤进行培养，并通过对原生动物总数的最大可能数估计来确定本土原生动物的反应。尽管每种土壤仅与一种添加的细菌一起培养，但通过对几种细菌的最大可能数估计来评估土壤对原生动物的反应。土壤原生动物对与强力细菌捕食者拜氏固氮菌或其猎物之一藤黄微球菌一起培养的土壤没有反应。拜氏固氮菌对原生动物也没有影响。因此，在这种情况下，除了可能对细菌猎物细胞的竞争外，细菌和原生动物捕食者没有相互作用。土壤原生动物对添加球形节杆菌或苏云金芽孢杆菌没有反应。因此，土壤中节杆菌属的本土状态以及苏云金芽孢杆菌的存活可能因这些物种对原生动物的抗性而得到增强。添加蕈状芽孢杆菌和大肠杆菌细胞引起了土壤原生动物的特定反应。对大肠杆菌有反应的原生动物对蕈状芽孢杆菌或任何其他细菌没有反应，反之亦然。因此，向土壤中添加非土壤细菌，如大肠杆菌，不会导致原生动物数量普遍增加，也不会导致原生动物对土壤中其他细菌活动的控制增加。
