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- Ultrasonic Treatment Enhanced Astaxanthin Production of Haematococcus pluvialis
- Yun Hwan Park , Jaewon Park , Jeong Sik Choi , Hyun Soo Kim , Jong Soon Choi , Yoon-E Choi
- J. Microbiol. 2023;61(6):633-639. Published online June 13, 2023
- DOI: https://doi.org/10.1007/s12275-023-00053-5
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Abstract
- In this study, effects of ultrasonic treatment on Haematococcus pluvialis (H. pluvialis) were investigated. It has been confirmed
that the ultrasonic stimulation acted as stress resources in the red cyst stage H. pluvialis cells containing astaxanthin,
result
ing in additional astaxanthin production. With the increase in production of astaxanthin, the average diameter of H. pluvialis cells increased accordingly. In addition, to determine how ultrasonic stimulation had an effect on the further biosynthesis of astaxanthin, genes related to astaxanthin synthesis and cellular ROS level were measured. As a result, it was confirmed that astaxanthin biosynthesis related genes and cellular ROS levels were increased, and thus ultrasonic stimulation acts as an oxidative stimulus. These results support the notion on the effect of the ultrasonic treatment, and we believe our novel approach based on the ultrasonic treatment would help to enhance the astaxanthin production from H. pluvialis.
- Metformin Regulates Gut Microbiota Abundance to Suppress M2 Skewing of Macrophages and Colorectal Tumorigenesis in Mice
- Linfeng Fan , Xiangfu Zeng , Guofeng Xu
- J. Microbiol. 2023;61(1):109-120. Published online January 26, 2023
- DOI: https://doi.org/10.1007/s12275-022-00010-8
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- 2 Citations
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Abstract
- The correlation of imbalanced gut microbiota with the onset and progression of colorectal cancer (CRC) has become clear. This work investigates the effect of metformin on gut microbiota and genesis of CRC in mice. Human fecal samples were collected from healthy control (HC) donors and CRC patients. Compared to HC donors, CRC patients had reduced abundance of gut microbiota; however, they had increased abundance of detrimental Bacteroidetes. Mice were injected with azomethane (AOM) to induce colorectal tumorigenesis models. Treatment of CRC patients-sourced fecal microbiota promoted tumorigenesis, and it increased the expression of Ki67, β-catenin, COX-2, and Cyclin D1 in mouse colon tissues. Further treatment of metformin blocked the colorectal tumorigenesis in mice. Fecal microbiota from the metformin-treated mice was collected, which showed decreased Bacteroidetes abundance and suppressed AOM-induced colorectal tumorigenesis in mice as well. Moreover, the metformin- modified microbiota promoted the M1 macrophage-related markers IL-6 and iNOS but suppressed the M2 macrophage-related markers IL-4R and Arg1 in mouse colon tissues. In conclusion, this study suggests that metformin-mediated gut microbiota alteration suppresses macrophage M2 polarization to block colorectal tumorigenesis.
- Effect of biostimulation and bioaugmentation on hydrocarbon degradation and detoxification of diesel-contaminated soil: a microcosm study
- Patricia Giovanella , Lídia de Azevedo Duarte , Daniela Mayumi Kita , Valéria Maia de Oliveira , Lara Durães Sette
- J. Microbiol. 2021;59(7):634-643. Published online May 15, 2021
- DOI: https://doi.org/10.1007/s12275-021-0395-2
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- 7 Citations
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Abstract
- Soil contamination with diesel oil is quite common during processes of transport and storage. Bioremediation is considered a safe, economical, and environmentally friendly approach for contaminated soil treatment. In this context, studies using hydrocarbon bioremediation have focused on total petroleum hydrocarbon (TPH) analysis to assess process effectiveness, while ecotoxicity has been neglected. Thus, this study aimed to select a microbial consortium capable of detoxifying diesel oil and apply this consortium to the bioremediation of soil contaminated with this environmental pollutant through different bioremediation approaches. Gas chromatography (GC-FID) was used to analyze diesel oil degradation, while ecotoxicological bioassays with the bioindicators Artemia sp., Aliivibrio fischeri (Microtox), and Cucumis sativus were used to assess detoxification. After 90 days of bioremediation, we found that the biostimulation and biostimulation/ bioaugmentation approaches showed higher rates of diesel oil degradation in relation to natural attenuation (41.9 and 26.7%, respectively). Phytotoxicity increased in the biostimulation and biostimulation/bioaugmentation treatments during the degradation process, whereas in the Microtox test, the toxicity was the same in these treatments as that in the natural attenuation treatment. In both the phytotoxicity and Microtox tests, bioaugmentation treatment showed lower toxicity. However, compared with natural attenuation, this approach did not show satisfactory hydrocarbon degradation. Based on the microcosm experiments results, we conclude that a broader analysis of the success of bioremediation requires the performance of toxicity bioassays.
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