Journal of Microbiology

Journal Article

Different distribution patterns of microorganisms between aquaculture pond sediment and water: Lili Dai , Chengqing Liu , Liang Peng , Chaofeng Song , Xiaoli Li , Ling Tao; J. Microbiol. 2021;59(4):376-388. Published online February 25, 2021; DOI: https://doi.org/10.1007/s12275-021-0635-5

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Abstract: Aquatic microorganisms in the sediment and water column are closely related; however, their distribution patterns between these two habitats still remain largely unknown. In this study, we compared sediment and water microeukaryotic and bacterial microorganisms in aquaculture ponds from different areas in China, and analyzed the influencing environmental factors as well as the inter-taxa relationships. We found that bacteria were significantly more abundant than fungi in both sediment and water, and the bacterial richness and diversity in sediment were higher than in water in all the sampling areas, but no significant differences were found between the two habitats for microeukaryotes. Bacterial taxa could be clearly separated through cluster analysis between the sediment and water, while eukaryotic taxa at all classification levels could not. Spirochaetea, Deltaproteobacteria, Nitrospirae, Ignavibacteriae, Firmicutes, Chloroflexi, and Lentimicrobiaceae were more abundantly distributed in sediment, while Betaproteobacteria, Alphaproteobacter, Cyanobacteria, Roseiflexaceae, Dinghuibacter, Cryomorphaceae, and Actinobacteria were more abundant in water samples. For eukaryotes, only Cryptomonadales were found to be distributed differently between the two habitats. Microorganisms in sediment were mainly correlated with enzymes related to organic matter decomposition, while water temperature, pH, dissolved oxygen, and nutrient levels all showed significant correlation with the microbial communities in pond water. Intensive interspecific relationships were also found among eukaryotes and bacteria. Together, our results indicated that eukaryotic microorganisms are distributed less differently between sediment and water in aquaculture ponds compared to bacteria. This study provides valuable data for evaluating microbial distributions in aquatic environments, which may also be of practical use in aquaculture pond management.

Research Support, Non-U.S. Gov'ts

Effects of a Dark-Septate Endophytic Isolate LBF-2 on the Medicinal Plant Lycium barbarum L.: Hai-han Zhang , Ming Tang , Hui Chen , Ya-jun Wang; J. Microbiol. 2012;50(1):91-96. Published online February 27, 2012; DOI: https://doi.org/10.1007/s12275-012-1159-9

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Abstract: Dark septate endophytes (DSE) are ubiquitous root associated fungi; however, our understanding of their ecological function remains unclear. Here, we investigated the positive effect of a DSE fungus on its host plant Lycium barbarum L. A DSE isolate, LBF-2, isolated from the roots of L. barbarum, was inoculated onto the roots of plants, which were grown under greenhouse conditions for five weeks. The result of molecular analyses of internal transcribed spacer regions indicated that LBF-2 was 96% similar to Paraphoma chrysanthemicola. Melanized septate hyphae were observed in the root cortical cells of L. barbarum using a light microscope. Inoculation with LBF-2 increased the total biomass by 39.2% and also enhanced chlorophyll fluorescence. Inoculation increased the concentration of total chlorophyll by 22.8% and of chlorophyll a by 21.3%, relative to uninoculated controls. These data indicate that the LBF-2 isolate might be used to facilitate the cultivation of L. barbarum, which has medicinal applications.

Dark Septate Endophyte (DSE) Fungi Isolated from Metal Polluted Soils: Their Taxonomic Position, Tolerance, and Accumulation of Heavy Metals In Vitro: Yujie Zhang , Yan Zhang , Maojun Liu , Xiaodong Shi , Zhiwei Zhao; J. Microbiol. 2008;46(6):624-632. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0163-6

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Abstract: To understand the possible role of the plant root associated fungi on metal tolerance, their role in the uptake of heavy metals and the potential transfer of these metal ions to the plant, three strains of dark septate endophytic (DSE) fungi were isolated from a waste smelter site in southwest China, and one strain was isolated from a non-contaminated site. According to molecular phylogenetic analysis of the ITS 1-5.8S rDNA-ITS 2 gene regions and morphological characteristics, one is identified as Exophiala pisciphila, and the other three are non-sporulating fungi under the experiment condition with the nearest phylogenetic affinities to the Thysanorea papuana strain EU041814. Tolerance and accumulation abilities of the three DSE strains for metals were investigated in liquid culture. Minimum inhibitory concentrations (MIC) of Pb, Zn, and Cd were determined. It was demonstrated that the tolerance of the DSE strains varied between metal species and strains. The E. pisciphila strain is able to accumulate lead and cadmium over 20% and 5% of dry weight of biomass, respectively. Partial of the sequestrated metals can be washed with CaCl2. Morphological and enzyme activity changes taking place in the presence of excessive Pb, Cd, and/or Zn also indicate that the mechanism of heavy metal tolerance and accumulation of the DSE strains would be a complex process. The findings indicated promising tolerance and accumulation of the DSE strains with potential values in metal cycling and restoration of soil and water system.

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