Seven methods for bacterial DNA extraction and purification from soil samples were compared. Holben’s direct lysis method recovered significantly greater amounts of DNA than the other methods tested, while CsCl‐ethidium bromide density gradient ultracentrifugation was better than gel filtration at removing humic acid from crude DNA isolated from soil. When both these methods were combined, 5·94 μg of DNA (A260/280 ratio around 1·754) was yielded g−1 oven‐dried sandstone shale alluvial soil; similarly satisfactory yields were obtained from Taiwan clay, and sandstone shale and slate alluvial soil managed under different farming practices. DNA obtained by these methods was readily digested by EcoR I and Hind III. When soil samples were stored for 3 weeks at 4 °C, the fraction of high‐molecular‐weight DNA was reduced significantly. Thus, DNA extraction should be carried out as soon as possible after a soil sample has been collected from the field. When hyphae of Pythium aphanidermatum and Fusarium solani were subjected to the above lysis method, DNA could not be detected in the extract.

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Among a large collection of Taiwanese soil isolates, a novel Gram-variable, rod-shaped, motile, endospore-forming bacterial strain, strain V10537 T , was subjected to a polyphasic study including 16S rRNA and gyrB gene sequence analysis, DNA-DNA hybridization experiments, cell wall peptidoglycan type, cellular fatty acid composition analysis and comparative phenotypic characterization. 16S rRNA gene sequence analysis indicated that the organism belonged to the genus Paenibacillus. Strain V10537T possessed meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan. It contained menaquinone MK-7 as the predominant isoprenoid quinone and anteiso-C 15 : 0 (53.6 %) and C 16 : 0 (19.0 %) as the major fatty acids. Phylogenetically, the most closely related species to strain V10537 T were Paenibacillus pabuli, Paenibacillus

A novel anamorphic yeast strain, A1-01(T), belonging to the genus Rhodotorula was isolated from a plant in Taiwan and analysed morphologically, physiologically and phylogenetically. Neither ballistoconidia nor sexual reproduction was observed. Sequence analysis of the 26S rRNA gene and the ITS region indicate that Rhodosporidium sphaerocarpum is the most closely related species, with 14 and 24 nucleotide substitutions, respectively. The novel species differed physiologically from R. sphaerocarpum in its ability to assimilate ethylamine and cadaverine, its inability to assimilate ethanol and nitrite. From these comparative analyses, the following novel yeast species is proposed: Rhodotorula taiwanensis sp. nov. with the type strain of A1-01(T) (BCRC 23118(T) = CBS 11729(T)).