The growth of 9 species of marine autotrophic microflagellates on or in solid-phase media were monitored by the use of Turner fluorophotometer. Gymnodinium nagasakiense, Fibrocapsa japonica, Prorocentrum micans, Chattonella antiqua and Heterosigma akashiwo could not grow, but Rhodomonas ovalis, Olisthodiscus luteus, Pavlova lutheri and Isochrysis galbana could be cultivated on or in the solid-phase media. Cells of these four species on or in the solid-phase media could grow vigorously after transferring into liquid media.

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Changes of chemical properties of lignite, collected from Shenyang Coal Mine, Liao Ning Province, Northeast China, and microbial succession on it with 4 years of weathering in open air were studied. With weathering, the content of total carbon and nitrogen, and C/N ratio decreased, while the ash content and the amount of organic matter which was extracted with 0.1M NaOH increased distinctly. UV-VIS spectra of humic and fulvic acids obtained from lignite samples changed systematically with weathering. Distribution of fulvic acids into adsorbed and nonadsorbed fractions with a cross-linked polyvinylpyrrolidone (PVP), which were regarded as humic and non-humic substances, respectively, was also changed. However, the IR spectra scarcely differed among the humic acids in lignite samples which were recently excavated and those which were weathered. Microbial succession on lignite was observed with weathering; actinomycetes as the first colonizers, followed by bacteria and then fungi. The dominant microorganisms were Actinosynnema sp., Streptomyces sp. and Nocardia sp. among actinomycetes, two Arthrobacter spp. among bacteria and two Aspergillus spp. among fungi.

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Two strains of pink-pigmented, chlorine-resistant bacteria, GK101 and GK118, previously isolated from pink-colored microbial biomass occurring in a potable water treatment system were studied phylogenetically by using 16S rRNA gene sequence information. 16S ribosomal DNA (rDNA) fragments of approximately 1.5kbp were amplified by the polymerase chain reaction (PCR) from crude cell lysates of the isolates and sequenced directly by a combined method consisting of linear PCR sequencing and automated fluorescence detection. Sequence comparisons and a phylogenetic tree analysis showed that the pink-pigmented isolates were closely related to Methylobacterium extorquens. Smaller fragments of 16S rDNA were also amplified from the bulk DNA extracted from the pink biomass, with a pair of PCR primers specific to the methylotrophs with the serine pathway or to proteobacteria of the alpha subclass. The PCR product was cloned by using the T-A cloning technique and sequenced as noted above. The results of this molecular approach suggested that bacteria phylogenetically the same as strain GK101 predominated in the pink-pigmented population in situ and that some other bacteria of the genus Methylobacterium might also be involved in formation of the pink-colored aggregates.

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Bacterial population in grassland soil (sampled in 1992) was studied in terms of component colony-forming curves (cCFCs) to be compared with that in soil sampled in 1987. The simulated colony-forming curve (CFC) pattern was essentially similar to that of the former study; that is, four cCFCs were observed during 163h of incubation time. Bacterial isolates were picked up from colonies appearing along each cCFC and clustered according to their morphological and physiological characteristics (biotypes). The histograms of the frequency distribution of t_r value for the isolates corresponding to cCFC groups I, II and III showed a similar pattern as previously. The trend of appearing of oligotrophic bacteria among the isolates of cCFCs groups was also similar to that of the former study although the percent of oligotrophic bacteria differed; that is, oligotrophic bacteria were not found among isolates of cCFCs groups I and II, appeared at 30% in cCFC group III and increased to 68% in cCFC group IV; as the oligotrophic bacteria increased, the sensitivity to 1% NaCl also increased. The bacterial population of the grassland soil is considered to be comprised of at least four component groups (cCFC groups) through yearly variations, although the biotype composition of the respective groups varies either widely or narrowly.

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As one of the mechanisms for horizontal gene transfer among microorganisms in marine environments, the production and significance of Phage-like particles (PLPs) were investigated using Ubiquinone 10 (Q10) possessing marine bacteria. 2, 4-Dichlorophenoxyacetic acid (2, 4-D) utilization was found as a characteristic feature of marine bacteria examined, and was employed as a marker for gene transfer. Their Plasmid-like elements (PLEs) transformed Escherichia coli AB1157 with the efficiency of 10⁶-10⁷CFU/μgDNA. The PLPs produced from Agrobacterium kieliense and Flavobacterium sp. 11604 showed 70-95% bactericidal activity on E. coli. At the same time, PLPs from A. kieliense transferred 2, 4-D utilization with efficiency of ca. 0.02% and those from F. sp. 11604 cured four amino acid requirements with efficiency of ca. 0.1% for each amino acid. The PLP production was generally shared by the bacteria investigated. These results indicate that the PLPs produced by certain marine bacteria may be an important new element for non-specific generalized transduction in the environment.

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