Microbial Resources and Systematics
Online ISSN : 2759-2006
Print ISSN : 1342-4041
Volume 38, Issue 1
Displaying 1-3 of 3 articles from this issue
  • Mikihide Demura, Mayuko Nishijima, Momo Yamane, Seiji Noma, Nobuyuki H ...
    2022 Volume 38 Issue 1 Pages 1-16
    Published: 2022
    Released on J-STAGE: July 26, 2024
    JOURNAL FREE ACCESS

    Microalgae are microorganisms that are attracting attention as biofuels, pharmaceuticals, and various industrial raw materials. Culture of“ native microalgal communities” is a low-cost method of achieving microalgal biomass production. These communities are populations of a wide variety of coexisting naturally growing microalgae and protists in a nutrient-rich medium. We aimed to both demonstrate whether it was possible to culture native microalgal communities year-round in Saga City, Saga Prefecture, Japan and determine the annual variation in fatty acid production, including highvalue-added fatty acids. We demonstrated the successful culture of native microalgal communities throughout the year (April 2019 to August 2020). Seasonal changes in dry cell weight (g/L) were highly correlated with shifts in the highest light quantum flux density (μmol/m2/s), indicating that light had a major impact on population culture. Microalgal diversity was very high at the beginning of culture but decreased over time and continued to be dominated by Scenedesmus spp. after September 2019. When this dominance began, the total lipid content increased, and it averaged about 10% (content per dry weight) in 2020. Fatty acids present at high rates throughout the year included α-linolenic acid and palmitic acid. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were detected irregularly.

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  • Koei Hamana, Hidenori Hayashi, Takemitsu Furuchi, Masaru Niitsu, Mitsu ...
    2022 Volume 38 Issue 1 Pages 17-30
    Published: 2022
    Released on J-STAGE: July 26, 2024
    JOURNAL FREE ACCESS

    To evaluate cellular polyamine distribution profiles as a chemotaxonomic marker to phylogenetic classification in bacteria, acid-extracted cellular polyamines from 134 strains (species) located in the 20 phyla, Armatimonadetes, Atribacterota, Balneolaeota, Elusimicrobia, Ignavibacteriae, Kiritimatiellaeota, Lentisphaerae, Rhodothermaeota, and Synergistetes, furthermore Acidobacteria, Chlorobi, Chloroflexi, Chrysiogenetes, Deferribacteres, Fusobacteria, Gemmatimonadetes, Nitrospirae, Planctomycetes, Spirochaetes, and Verrucomicrobia were additionally analyzed by HPLC and HPGC. In 29 strains (species) of the 9 phyla first analyzed, Armatimonas and Fimbriimonas were absent (undetectable) in polyamines and Capsulimonas contained homospermidine in the phylum Armatimonadetes. Atribacter of the Atribacterota contained putrescine, spermidine and spermine. Alifodinibius lacked polyamines and Gracilimonas contained homospermidine in the phylum Balneolaeota. Elusimicrobium of the phylum Elusimicrobia contained homospermidine. Homospermidine was found in Igmavibacterium, and putrescine, spermidine, homospermidine and spermine were found in Melioribacter in the phylum Ignavibacteriae. Kiritimatiella of the phylum Kiritimatiellaeota contained spermidine and spermine. In the phylum Lentisphaerae, Lentisphaera contained spermidine and homospermidine, and Victivallis and Oligosphaera contained spermidine alone. In the phylum Rhodothermaeota, Rubricoccus was absent in polyamines, Rubrivirga lacked polyamines or contained homospermidine, and Longimonas contained spermidine. Spermidine and spermine were major polyamines in Acetomicrobium, Aminiphilus, Aminovibrio, Aminobacterium, Aminomonas, Cloacibacilus, Dethiosulfovibrio, Fretibacterium, Lactivibrio, Pyramidobacter, and Thermoanaerovibrio of the phylum Synergistetes. Although the numbers of analyzed species was not enough to the evaluation of phylogenetic significance in the 9 phyla. In the 105 additionally analyzed strains (species) belonging to 11 other phyla, correlation of their phylogenetic locations and spermidine, homospermidine, and spermine distributions were discussed.

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  • Atsushi Hisatomi, Yuh Shiwa, Nobuyuki Fujita, Naoto Tanaka
    2022 Volume 38 Issue 1 Pages 31-40
    Published: 2022
    Released on J-STAGE: July 26, 2024
    JOURNAL FREE ACCESS

    Siderophores are structurally diverse chelating compounds produced by organisms in iron-starved environments, which form complexes with iron and are taken up only by organisms with structure-specific receptors. In bacteria, it is known that siderophores are both responsible for iron uptake, and that their production and uptake are linked to biofilm formation. Therefore, the addition of siderophores to an environment where there is insufficient iron for bacterial growth may affect the growth of some bacteria and biofilm formation. This study investigates the effects of 2,3-dihydroxybenzoyl-L-serine (DHBS) as a siderophore on biofilm formation in soil and water samples and the characteristics of isolates from biofilm induced by DHBS. These results showed that the addition of DHBS to soil and water samples induced biofilm formation and that the biofilm constituent comprised strains of Pesudomonas species, which strongly promoted biofilm formation via the uptake of DHBS iron complexes.

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