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Abstract
Acetobacter species are a major component of the gut microbiome of the fruit fly Drosophila melanogaster, a widely used model organism. While a range of studies have illuminated impacts of Acetobacter on their hosts, less is known about how association with the host impacts bacteria. A previous study identified that a purine salvage locus was commonly found in Acetobacter associated with Drosophila. In this study, we sought to verify the functions of predicted purine salvage genes in Acetobacter fabarum DsW_054 and to test the hypothesis that these bacteria can utilize host metabolites as a sole source of nitrogen. Targeted gene deletion and complementation experiments confirmed that genes encoding xanthine dehydrogenase (xdhB), urate hydroxylase (urhA), and allantoinase (puuE) were required for growth on their respective substrates as the sole source of nitrogen. Utilization of urate by Acetobacter is significant because this substrate is the major nitrogenous waste product of Drosophila, and its accumulation in the excretory system is detrimental to both flies and humans. The potential significance of our findings for host purine homeostasis and health are discussed, as are the implications for interactions among microbiota members, which differ in their capacity to utilize host metabolites for nitrogen. IMPORTANCEAcetobacter are commonly found in the gut microbiota of fruit flies, including Drosophila melanogaster. We evaluated the function of purine salvage genes in Acetobacter fabarum to test the hypothesis that this bacterium can utilize host metabolites as a source of nitrogen. Our results identify functions for three genes required for growth on urate, a major host waste product. The utilization of this and other Drosophila metabolites by gut bacteria may play a role in their survival in the host environment. Future research into how microbial metabolism impacts host purine homeostasis may lead to therapies because urate accumulation in the excretory system is detrimental to flies and humans.
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Kataoka N, Matsutani M, Murata R, Koga R, Nantapong N, Yakushi T, Matsushita K. Potassium ion leakage impairs thermotolerance in Corynebacterium glutamicum. J Biosci Bioeng 2021; 133:119-125. [PMID: 34789412 DOI: 10.1016/j.jbiosc.2021.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/21/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022]
Abstract
Corynebacterium glutamicum, a gram-positive bacterium, can produce amino acids such as glutamic acid and lysine. The heat generated during cell growth and/or glutamate fermentation disturbs both the cell growth and fermentation. To overcome such a negative effect of the fermentation heat, we have tried to establish a high temperature fermentation. One of the approach is to create a thermotolerant strains, while the other is to create an optimum culture conditions able for the strain to grow at higher temperatures. In this study, we focused on the latter approach, where we examined the effect of potassium ion on cell growth at high growth temperatures of C. glutamicum. The supplementation of high concentrations of potassium chloride (300 mM) (or sorbitol, an osmolyte) mitigated the repressed cell growth induced by high temperature at 39 °C or 40 °C. The intracellular potassium concentration declines from 300 mM to ∼150 mM by increasing the growth temperature but not by supplementing potassium chloride or sorbitol. Furthermore, in vitro experiments revealed that the potassium ion leakage occurs at high temperatures, which was mitigated in the presence of high concentrations of extracellular potassium chloride. This suggested that the presence of high osmolyte in the culture medium could inhibit the potassium ion leakage induced by high temperature and subsequently support cell growth at high temperatures.
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Affiliation(s)
- Naoya Kataoka
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Minenosuke Matsutani
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Ryutarou Murata
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Ryo Koga
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Nawarat Nantapong
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 3000, Thailand
| | - Toshiharu Yakushi
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Kazunobu Matsushita
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan.
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Xia K, Han C, Xu J, Liang X. Transcriptome response of Acetobacter pasteurianus Ab3 to high acetic acid stress during vinegar production. Appl Microbiol Biotechnol 2020; 104:10585-10599. [PMID: 33156446 DOI: 10.1007/s00253-020-10995-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/01/2020] [Accepted: 10/31/2020] [Indexed: 12/12/2022]
Abstract
Acetic acid accumulation is a universal limiting factor to the vinegar manufacture because of the toxic effect of acetic acid on the acid producing strain, such as Acetobacter pasteurianus. In this study, we aimed to investigate the genome-wide transcriptional response of A. pasteurianus Ab3 to high acid stress during vinegar production. By comparing the transcriptional landscape of cells harvested from a long-term cultivation with high acidity (70 ± 3 g/L) to that of low acidity (10 ± 2 g/L), we demonstrated that 1005 genes were differentially expressed. By functional enrichment analysis, we found that the expression of genes related to the two-component systems (TCS) and toxin-antitoxin systems (TAS) was significantly regulated under high acid stress. Cells increased the genome stability to withstand the intracellular toxicity caused by the acetic acid accumulation by repressing the expression of transposases and integrases. Moreover, high acid stress induced the expression of genes involved in the pathways of peptidoglycan, ceramide, and phosphatidylcholine biosynthesis as well as the Tol-Pal and TonB-ExbB systems. In addition, we observed that cells increased and diversified the ATP production to resist high acid stress. Transcriptional upregulation in the pathways of pyrroloquinoline quinone (PQQ) synthesis and thiamine metabolism suggested that cells may increase the production of prosthetic groups to ensure the enzyme activity upon high acid stress. Collectively, the results of this study increase our current understanding of the acetic acid resistance (AAR) mechanisms in A. pasteurianus and provide opportunities for strain improvement and scaled-up vinegar production.Key Points• TCS and TAS are responsive to the acid stress and constitute the regulating networks.• Adaptive expression changes of cell envelope elements help cell resist acid stress.• Cells promote genome stability and diversify ATP production to withstand acid stress.
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Affiliation(s)
- Kai Xia
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Chengcheng Han
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Jun Xu
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Xinle Liang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.
- Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.
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Comparative Genomic Analysis of Closely Related Acetobacter pasteurianus Strains Provides Evidence of Horizontal Gene Transfer and Reveals Factors Necessary for Thermotolerance. J Bacteriol 2020; 202:JB.00553-19. [PMID: 32015144 DOI: 10.1128/jb.00553-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/25/2020] [Indexed: 12/11/2022] Open
Abstract
Acetobacter pasteurianus is an industrial strain used for the vinegar production. Many A. pasteurianus strains with different phenotypic characteristics have been isolated so far. To understand the genetic background underpinning these phenotypes, a comparative genomic analysis of A. pasteurianus strains was conducted. Based on bioinformatics and experimental results, we report the following. (i) The gene repertoire related to the respiratory chains showed that several horizontal gene transfer events occurred after the divergence of these strains, indicating that the respiratory chain in A. pasteurianus has the diversity to adapt to its environment. (ii) There is a clear difference in thermotolerance even between 12 closely related strains. NBRC 3279, NBRC 3284, and NBRC 3283, in particular, which have only 55 mutations in total, showed differences in thermotolerance. The Na+/H+ antiporter gene nhaK2 was mutated in the thermosensitive NBRC 3279 and NBRC 3284 strains and not in the thermotolerant NBRC 3283 strain. The Na+/H+ antiporter activity of the three strains and expression of nhaK2 gene from NBRC 3283 in the two thermosensitive strains showed that these mutations are critical for thermotolerance. These results suggested that horizontal gene transfer events and several mutations have affected the phenotypes of these closely related strains.IMPORTANCE Acetobacter pasteurianus, an industrial vinegar-producing strain, exhibits diverse phenotypic differences such as respiratory activity related to acetic acid production, acetic acid resistance, or thermotolerance. In this study, we investigated the correlations between genome sequences and phenotypes among closely related A. pasteurianus strains. The gene repertoire related to the respiratory chains showed that the respiratory components of A. pasteurianus has a diversity caused by several horizontal gene transfers and mutations. In three closely related strains with clear differences in their thermotolerances, we found that the insertion or deletion that occurred in the Na+/H+ antiporter gene nhaK2 is directly related to their thermotolerance. Our study suggests that a relatively quick mutation has occurred in the closely related A. pasteurianus due to its genetic instability and that this has largely affected its phenotype.
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Xia K, Zang N, Zhang J, Zhang H, Li Y, Liu Y, Feng W, Liang X. New insights into the mechanisms of acetic acid resistance in Acetobacter pasteurianus using iTRAQ-dependent quantitative proteomic analysis. Int J Food Microbiol 2016; 238:241-251. [PMID: 27681379 DOI: 10.1016/j.ijfoodmicro.2016.09.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 12/01/2022]
Abstract
Acetobacter pasteurianus is the main starter in rice vinegar manufacturing due to its remarkable abilities to resist and produce acetic acid. Although several mechanisms of acetic acid resistance have been proposed and only a few effector proteins have been identified, a comprehensive depiction of the biological processes involved in acetic acid resistance is needed. In this study, iTRAQ-based quantitative proteomic analysis was adopted to investigate the whole proteome of different acidic titers (3.6, 7.1 and 9.3%, w/v) of Acetobacter pasteurianus Ab3 during the vinegar fermentation process. Consequently, 1386 proteins, including 318 differentially expressed proteins (p<0.05), were identified. Compared to that in the low titer circumstance, cells conducted distinct biological processes under high acetic acid stress, where >150 proteins were differentially expressed. Specifically, proteins involved in amino acid metabolic processes and fatty acid biosynthesis were differentially expressed, which may contribute to the acetic acid resistance of Acetobacter. Transcription factors, two component systems and toxin-antitoxin systems were implicated in the modulatory network at multiple levels. In addition, the identification of proteins involved in redox homeostasis, protein metabolism, and the cell envelope suggested that the whole cellular system is mobilized in response to acid stress. These findings provide a differential proteomic profile of acetic acid resistance in Acetobacter pasteurianus and have potential application to highly acidic rice vinegar manufacturing.
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Affiliation(s)
- Kai Xia
- Department of Biochemical Engineering, School of Food Science and Biochemical Engineering, Zhejiang Gongshang University, Hangzhou 310025, China
| | - Ning Zang
- Medical Scientific Research Center, Guangxi Medical University, Nanning 530021, China
| | - Junmei Zhang
- Department of Biochemical Engineering, School of Food Science and Biochemical Engineering, Zhejiang Gongshang University, Hangzhou 310025, China
| | - Hong Zhang
- Department of Biochemical Engineering, School of Food Science and Biochemical Engineering, Zhejiang Gongshang University, Hangzhou 310025, China
| | - Yudong Li
- Department of Biochemical Engineering, School of Food Science and Biochemical Engineering, Zhejiang Gongshang University, Hangzhou 310025, China
| | - Ye Liu
- Zhejiang Wuweihe Food Co. Ltd., Huzhou 313213, China
| | - Wei Feng
- Zhejiang Wuweihe Food Co. Ltd., Huzhou 313213, China
| | - Xinle Liang
- Department of Biochemical Engineering, School of Food Science and Biochemical Engineering, Zhejiang Gongshang University, Hangzhou 310025, China.
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