Microbiology Program, The Pennsylvania State University, University Park, Pennsylvania 16802.
Appl Environ Microbiol. 1983 Oct;46(4):881-8. doi: 10.1128/aem.46.4.881-888.1983.
Agromyces ramosus occurs in very high numbers in most soils and, based on studies of laboratory isolates, does not require host cells for growth. Nevertheless, it attacked and destroyed most of the gram-positive and gram-negative bacterial species tested as possible host organisms. A. ramosus also attacked and destroyed Saccharomyces cerevisiae. The possibility of attack on fungi was unclear. Among the bacteria serving as hosts were the important soil species Azotobacter vinelandii, Rhizobium leguminosarum, Rhizobium meliloti, and Agrobacterium tumefaciens. Dead cells were not attacked. A. vinelandii cysts were attacked but left unharmed. To some extent, A. vinelandii seemed to survive this attack by encysting. Attack by A. ramosus occurred in natural soil and over a broad range of nutritional levels in laboratory media. The attack did not seem to be a means for obtaining an increased supply of commonly available nutrients. Instead, it seemed to be a means of obtaining something produced, perhaps in small amounts, by a variety of organisms, but not by all organisms. Several types of culture filtrates were tested for activity. The filtrates neither stimulated nor inhibited the growth of A. ramosus or the host organisms. The availability of catalase activity in host organisms did not seem to be involved. It is not known whether the attack by Agromyces ramosus in soil can be manipulated to cause a decrease in numbers of Agrobacterium tumefaciens or other pathogens without simultaneously depressing the numbers of beneficial organisms in this habitat.
长梗木霉在大多数土壤中数量极高，并且根据实验室分离株的研究，它的生长不需要宿主细胞。然而，它攻击并破坏了作为可能宿主生物测试的大多数革兰氏阳性和革兰氏阴性细菌物种。木霉也攻击并破坏了酿酒酵母。对真菌的攻击可能性尚不清楚。作为宿主的细菌包括重要的土壤物种固氮菌、根瘤菌、根瘤菌和根癌农杆菌。死细胞不会被攻击。木霉孢囊受到攻击但未受损。在某种程度上，木霉似乎通过形成孢囊来存活这种攻击。木霉在自然土壤和实验室培养基中广泛的营养水平下发生攻击。这种攻击似乎不是为了获得更丰富的常用营养物质供应的手段。相反，它似乎是获取某种由多种生物产生的物质的手段，但不是所有生物都能产生这种物质。几种类型的培养液滤液被测试其活性。这些滤液既没有刺激也没有抑制木霉或宿主生物的生长。宿主生物中过氧化氢酶活性的可用性似乎没有参与其中。目前尚不清楚在土壤中木霉的攻击是否可以被操纵，以减少根癌农杆菌或其他病原体的数量，而不会同时抑制该栖息地中有益生物的数量。
