By using baiting techniques and different purification methods, a high number of myxobacterial strains have been isolated as pure cultures from soil of different regions of China. Because myxobacterial cells do not disperse easily in liquid media, a medium containing an enzymatic hydrolysate of casein (CEH) medium have been used for purification and purity tests combined in a single step. The key method, in which isolates are reintroduced to sterile rabbit dung to induce fruiting bodies formation, facilitates purification of myxobacteria. Sterile rabbit dung pellets are used to mimic the natural growth substance of these organisms which has the advantage that characteristic fruiting bodies emerge, which is a key characteristics in the taxonomy of myxobacteria. In this study, the optimum program of isolation and purification of some myxobacteria strains has been established which will facilitate screening programs. Moreover, the development of fruiting body formation of strain BD20 (Chondromyces) and strain BD54 (Cystobacter) have been recorded in this study.

用16SrRNA部分序列对Williams 数值分类系统所包含的链霉菌属种或种群进行系统进化分析。以包含16SrRNA 基因V-2高变区在内的120bp长核苷酸序列所作的系统进化树表明：这些链霉菌可分为34个簇，其中大簇5个（包括27～85株菌株）；中等大小簇3个（包括9～12株菌）；小簇8个（包括2～6株菌）；单成员簇19个。结果同时表明，Williams 数值分类系统中根据形态、生理、生化特征进行归类而得的种或种群内存在较大异质性。

A catalase-negative actinomycete, strain YIM 21741T, was isolated from a soil sample collected from a primeval forest at Xishuangbanna, Yunnan Province, China. Analysis of 16S rDNA showed the strain to be related to members of the genus Agromyces, with which it also shares morphological characteristics, e.g. branching hyphae breaking into diphtheroid and rod-like, irregular, non-motile fragments and a peptidoglycan containing the diagnostic amino acid 2,4-diamino-n-butyric acid. Whole-cell hydrolysates of strain YIM 21741T contained rhamnose and small quantities of glucose, galactose and mannose. The major menaquinone was MK-12, while MK-13 and MK-12 were minor components. Diagnostic phospholipids were phosphatidylglycerol and diphosphatidylglycerol. The G+C content of the DNA was 72

A psychrotolerant actinomycete, strain YIM6T, was isolated from a soil sample collected from Beijiang in Xinjiang Province, China. Both vegetative and aerial hyphae grew well on various media after 4 weeks. Long spore chains, borne on the aerial mycelium, were straight to flexuous or occasionally Retinaculiaperti and non-motile. The novel isolate grew well at between 8 and 20℃; the lower and upper temperature limits for growth were 0 and 32℃. The cell wall of strain YIM6T contained LL-diaminopimelic acid (A2pm) and traces of meso-A2pm. Whole-cell hydrolysates contained mainly glucose and small amounts of xylose, galactose and arabinose. The predominant menaquinones were MK9(H6) and MK-9(H8) and phosphatidylethanolamine was the diagnostic phospholipid. The predominant cellular fatty acids were 15∶0 anteiso, 16∶0 iso and 17∶0 cyclo. Phylogenetic analysis indicated that strain YIM6T belongs to the genus Streptomyces. In its morphology, physiological and biochemical characteristics and 16S rDNA sequence, strain YIM6T differed from other members of Streptomyces. Thus, strain YIM6T (=CCTCC 99005T=AS 4.1718T= DSM 41794T) is proposed as the type strain of a novel species, Streptomyces beijiangensis sp. nov.

Actinomycete strain YIM 90002T (=CCTCC 99003T=CCRC 16284T) was isolated from a soil sample collected from a salt lake in the west of China. The aerial mycelium of this organism is well developed but not fragmented and, at maturity, forms short chains of spores. Spores in short chains are oval-to rodshaped and have wrinkled surfaces. Substrate mycelium is branched with nonfragmenting hyphae and forms single oval to round spores borne on sporophores or dichotomously branching sporophores. Single spores have wrinkled surfaces. Single spores and spores in short chains are non-motile. Strain YIM 90002T contains meso-diaminopimelic acid, DD-diaminopimelic acid, glycine, lysine and aspartic acid in its cell wall and has glucose, galactose, ribose, xylose, arabinose and mannose as whole-cell sugars (no diagnostic sugars). The phospholipids are phosphatidylglycerol, phosphatidylinositol and phosphatidylethanolamine. The major menaquinones are MK-9(H6), MK-10(H2) and MK-10(H4). Phylogenetic data indicate that this strain belongs to the family Nocardiopsaceae. The morphological and physiological characteristics and chemotaxonomic and phylogenetic data for this strain differ from those of previously described actinomycetes. Therefore, a new genus, Streptimonospora, is proposed for this organism; the type species of the genus is Streptimonospora salina gen. nov., sp. nov., and the type strain of S. salina is strain YIM 90002T.