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He S, Li L, Lei S, Su J, Zhang Y, Zeng H. Effect of lotus seed resistant starch on the bioconversion pathway of taurocholic acid by regulating the intestinal microbiota. Int J Biol Macromol 2024; 266:131174. [PMID: 38552699 DOI: 10.1016/j.ijbiomac.2024.131174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/19/2024] [Accepted: 03/26/2024] [Indexed: 04/02/2024]
Abstract
Taurocholic acid (TCA) is abundant in the rat intestine and has multiple health benefits. In the gut, intestinal microbiota can transform TCA into different bile acid (BA) derivatives, with the composition of microbiota playing a crucial role in the transformation process. This study aims to investigate how lotus seed resistant starch (LRS) can regulate microbiota to influence BA transformation. A fecal fermentation study was conducted in vitro, using either LRS, high-amylose maize starch (HAMS), or glucose (GLU) to analyze microbiota composition, BA content, and metabolic enzyme activities over different fermentation times. Bioinformatics analysis found that LRS increased the relative abundance of Enterococcus, Bacillus, and Lactobacillus, and decreased Escherichia-Shigella, compared with HAMS and GLU. LRS also reduced total BA content and accelerated the conversion of TCA to cholic acid, deoxycholic acid, and other derivatives. These results reveal that LRS and GLU tend to mediate the dehydroxy pathway, whereas HAMS tends to secrete metabolic enzymes in the epimerization pathway. Therefore, the evidence that LRS may regulate TCA bioconversion may benefit human colon health research and provide an important theoretical basis, as well as offer new concepts for the development of functional foods.
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Affiliation(s)
- Shuqi He
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lanxin Li
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Suzhen Lei
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jinhan Su
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yi Zhang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China; China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Hongliang Zeng
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China; China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Machado MAM, Chapartegui-González I, Castro VS, Figueiredo EEDS, Conte-Junior CA, Torres AG. Biofilm-producing Escherichia coli O104:H4 overcomes bile salts toxicity by expressing virulence and resistance proteins. Lett Appl Microbiol 2024; 77:ovae032. [PMID: 38573831 DOI: 10.1093/lambio/ovae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/15/2024] [Accepted: 04/03/2024] [Indexed: 04/06/2024]
Abstract
We investigated bile salts' ability to induce phenotypic changes in biofilm production and protein expression of pathogenic Escherichia coli strains. For this purpose, 82 pathogenic E. coli strains isolated from humans (n = 70), and animals (n = 12), were examined for their ability to form biofilms in the presence or absence of bile salts. We also identified bacterial proteins expressed in response to bile salts using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-electrophoresis) and liquid chromatography-mass spectrometry (LC-MS/MS). Lastly, we evaluated the ability of these strains to adhere to Caco-2 epithelial cells in the presence of bile salts. Regarding biofilm formation, two strains isolated from an outbreak in Republic of Georgia in 2009 were the only ones that showed a high and moderate capacity to form biofilm in the presence of bile salts. Further, we observed that those isolates, when in the presence of bile salts, expressed different proteins identified as outer membrane proteins (i.e. OmpC), and resistance to adverse growth conditions (i.e. F0F1, HN-S, and L7/L12). We also found that these isolates exhibited high adhesion to epithelial cells in the presence of bile salts. Together, these results contribute to the phenotypic characterization of E. coli O104: H4 strains.
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Affiliation(s)
- Maxsueli Aparecida Moura Machado
- Food Science Program (PPGCAL), Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro 21941-909, Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria, Rio de Janeiro 21941-598, RJ, Brazil
- Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM), Department of Biochemistry, Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria, Rio de Janeiro 21941-909, RJ, Brazil
| | - Itziar Chapartegui-González
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, United States
| | - Vinicius Silva Castro
- Animal Science Program (PPGCA). Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil
- Nutrition, Food and Metabolism Program (PPGNAM). Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil
| | - Eduardo Eustáquio de Souza Figueiredo
- Animal Science Program (PPGCA). Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil
- Nutrition, Food and Metabolism Program (PPGNAM). Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso 78060-900, Brazil
| | - Carlos Adam Conte-Junior
- Food Science Program (PPGCAL), Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro 21941-909, Brazil
- Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria, Rio de Janeiro 21941-598, RJ, Brazil
- Laboratory of Advanced Analysis in Biochemistry and Molecular Biology (LAABBM), Department of Biochemistry, Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria, Rio de Janeiro 21941-909, RJ, Brazil
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, United States
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Pushpker R, Bay DC, Turner RJ. Small multidrug resistance protein EmrE phenotypically associates with OmpW, DcrB and YggM for osmotic stress protection by betaine in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748554 DOI: 10.1099/mic.0.001287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The small multidrug resistance (SMR) protein EmrE resides in the inner membrane and provides resistance against a wide range of antiseptic quaternary cationic compounds (QCCs) for the Gram-negative bacterium Escherichia coli. We have reported previously that overexpression of the emrE gene results in the reduction of pH and osmotic tolerance, likely through EmrE-mediated biological QCC-based osmoprotectant efflux, indicating a potential physiological role for EmrE beyond providing drug resistance. EmrE is the most studied member of SMR transporter family; however, it is not known how the substrates translocated by EmrE move across the periplasm and through the outer membrane (OM). We have shown that the OM protein OmpW participates in the EmrE-mediated substrate efflux process and provided a hypothesis for the present study that additional OM and periplasmic proteins participate in the translocation process. To test the hypothesis, we conducted alkaline pH-based growth phenotype screens under emrE overexpression conditions. This screen identified 10 additional genes that appear to contribute to the EmrE-coupled osmoprotectant efflux: gspD, hofQ, yccZ, acrA, emrA, emrB, proX, osmF, dcrB and yggM. Further screening of these genes using a hyperosmotic growth phenotype assay in the presence and the absence of the osmoprotectant glycine betaine identified ompW and two periplasmic protein genes, dcrB and yggM, are mechanistically linked to EmrE.
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Affiliation(s)
- Rajnigandha Pushpker
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Denice C Bay
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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Liu J, Wu A, Cai J, She ZG, Li H. The contribution of the gut-liver axis to the immune signaling pathway of NAFLD. Front Immunol 2022; 13:968799. [PMID: 36119048 PMCID: PMC9471422 DOI: 10.3389/fimmu.2022.968799] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the liver manifestation of metabolic syndrome and is the most common chronic liver disease in the world. The pathogenesis of NAFLD has not been fully clarified; it involves metabolic disturbances, inflammation, oxidative stress, and various forms of cell death. The “intestinal-liver axis” theory, developed in recent years, holds that there is a certain relationship between liver disease and the intestinal tract, and changes in intestinal flora are closely involved in the development of NAFLD. Many studies have found that the intestinal flora regulates the pathogenesis of NAFLD by affecting energy metabolism, inducing endotoxemia, producing endogenous ethanol, and regulating bile acid and choline metabolism. In this review, we highlighted the updated discoveries in intestinal flora dysregulation and their link to the pathogenesis mechanism of NAFLD and summarized potential treatments of NAFLD related to the gut microbiome.
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Affiliation(s)
- Jiayi Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Institute of Model Animal of Wuhan University, Wuhan, China
| | - Anding Wu
- Department of general surgery, Huanggang Central Hospital, Huanggang, China
- Huanggang Institute of Translation Medicine, Huanggang, China
| | - Jingjing Cai
- Department of Cardiology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Zhi-Gang She
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Institute of Model Animal of Wuhan University, Wuhan, China
- *Correspondence: Zhi-Gang She, ; Hongliang Li,
| | - Hongliang Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Institute of Model Animal of Wuhan University, Wuhan, China
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
- *Correspondence: Zhi-Gang She, ; Hongliang Li,
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Liu Y, Zhang S, Zhou W, Hu D, Xu H, Ji G. Secondary Bile Acids and Tumorigenesis in Colorectal Cancer. Front Oncol 2022; 12:813745. [PMID: 35574393 PMCID: PMC9097900 DOI: 10.3389/fonc.2022.813745] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/21/2022] [Indexed: 01/11/2023] Open
Abstract
Colorectal cancer (CRC) is one of the most common and deadly cancers in the world and is a typical inflammatory tumor. In recent years, the incidence of CRC has been increasing year by year. There is evidence that the intake of high-fat diet and overweight are associated with the incidence of CRC, among which bile acids play a key role in the pathogenesis of the disease. Studies on the relationship between bile acid metabolism and the occurrence of CRC have gradually become a hot topic, improving the understanding of metabolic factors in the etiology of colorectal cancer. Meanwhile, intestinal flora also plays an important role in the occurrence and development of CRC In this review, the classification of bile acids and their role in promoting the occurrence of CRC are discussed, and we highlights how a high-fat diet affects bile acid metabolism and destroys the integrity of the intestinal barrier and the effects of gut bacteria.
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Affiliation(s)
- Yujing Liu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Shengan Zhang
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wenjun Zhou
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Dan Hu
- Department of Internal Medicine of Chinese Medicine, Shanghai Pudong New Area Hospital of Traditional Chinese Medicine, Shanghai, China
| | - Hanchen Xu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Guang Ji
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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A negative charge at position D+5 of Motif A is critical for function of the major facilitator superfamily multidrug/H+ antiporter MdtM. EXPERIMENTAL RESULTS 2022. [DOI: 10.1017/exp.2022.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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7
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Feller FM, Holert J, Yücel O, Philipp B. Degradation of Bile Acids by Soil and Water Bacteria. Microorganisms 2021; 9:1759. [PMID: 34442838 PMCID: PMC8399759 DOI: 10.3390/microorganisms9081759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/22/2021] [Accepted: 08/12/2021] [Indexed: 02/07/2023] Open
Abstract
Bile acids are surface-active steroid compounds with a C5 carboxylic side chain at the steroid nucleus. They are produced by vertebrates, mainly functioning as emulsifiers for lipophilic nutrients, as signaling compounds, and as an antimicrobial barrier in the duodenum. Upon excretion into soil and water, bile acids serve as carbon- and energy-rich growth substrates for diverse heterotrophic bacteria. Metabolic pathways for the degradation of bile acids are predominantly studied in individual strains of the genera Pseudomonas, Comamonas, Sphingobium, Azoarcus, and Rhodococcus. Bile acid degradation is initiated by oxidative reactions of the steroid skeleton at ring A and degradation of the carboxylic side chain before the steroid nucleus is broken down into central metabolic intermediates for biomass and energy production. This review summarizes the current biochemical and genetic knowledge on aerobic and anaerobic degradation of bile acids by soil and water bacteria. In addition, ecological and applied aspects are addressed, including resistance mechanisms against the toxic effects of bile acids.
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Affiliation(s)
- Franziska Maria Feller
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Corrensstr. 3, 48149 Münster, Germany; (F.M.F.); (J.H.); (O.Y.)
| | - Johannes Holert
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Corrensstr. 3, 48149 Münster, Germany; (F.M.F.); (J.H.); (O.Y.)
| | - Onur Yücel
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Corrensstr. 3, 48149 Münster, Germany; (F.M.F.); (J.H.); (O.Y.)
| | - Bodo Philipp
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Corrensstr. 3, 48149 Münster, Germany; (F.M.F.); (J.H.); (O.Y.)
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Auf dem Aberg 1, 57392 Schmallenberg, Germany
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Salam LB, Obayori OS, Ilori MO, Amund OO. Impact of spent engine oil contamination on the antibiotic resistome of a tropical agricultural soil. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:1251-1271. [PMID: 33993436 DOI: 10.1007/s10646-021-02422-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Profiling of hydrocarbon-contaminated soils for antibiotic resistance genes (ARGs) is becoming increasingly important due to emerging realities of their preponderance in hydrocarbon-inundated matrices. In this study, the antibiotic resistome of an agricultural soil (1S) and agricultural soil contaminated with spent engine oil (AB1) were evaluated via functional annotation of the open reading frames (ORFs) of their metagenomes using the comprehensive antibiotic database (CARD) and KEGG KofamKOALA. CARD analysis of AB1 metagenome revealed the detection of 24 AMR (antimicrobial resistance) gene families, 66 ARGs, and the preponderance (69.7%) of ARGs responsible for antibiotic efflux in AB1 metagenome. CARD analysis of 1S metagenome revealed four AMR gene families and five ARGs. Functional annotation of the two metagenomes using KofamKOALA showed 171 ARGs in AB1 and 29 ARGs in 1S, respectively. Majority of the detected ARGs in AB1 (121; 70.8%) and 1S (16; 55.2%) using KofamKOALA are responsible for antibiotic efflux while ARGs for other resistance mechanisms were also detected. All the five major antibiotic efflux pump systems were detected in AB1 metagenome, though majority of the ARGs for antibiotic efflux belong to the RND (resistance-nodulation-cell division) and MFS (major facilitator superfamily) efflux systems. Significant differences observed in the ARGs recovered from 1S and AB1 metagenomes were statistically validated (P < 0.05). SEO contamination is believed to be responsible for ARGs increase in AB1 metagenome via mechanisms of cross-resistance especially with efflux pumps. The detection of these ARGs is of great public health concern in this era of multidrug resistant isolates resurgence.
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Affiliation(s)
- Lateef Babatunde Salam
- Department of Biological Sciences, Microbiology Unit, Summit University, Offa, Kwara, Nigeria.
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Wang X, Wang Y, Ling N, Shen Y, Zhang D, Liu D, Ou D, Wu Q, Ye Y. Effects of tolC on tolerance to bile salts and biofilm formation in Cronobacter malonaticus. J Dairy Sci 2021; 104:9521-9531. [PMID: 34099300 DOI: 10.3168/jds.2021-20128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/29/2021] [Indexed: 12/21/2022]
Abstract
Bile salts is one of essential components of bile secreted into the intestine to confer antibacterial protection. Cronobacter species are associated with necrotizing enterocolitis in newborns and show a strong tolerance to bile salts. However, little attempt has been made to focus on the molecular basis of the tolerance to bile salts. In this study, we investigated the roles of tolC on growth, cell morphology, motility, and biofilm formation ability in Cronobacter malonaticus under bile salt stress. The results indicated that the absence of tolC significantly affected the colony morphology and outer membrane structure in a normal situation, compared with those of the wild type strain. The deletion of tolC caused the decline in resistance to bile salt stress, inhibition of growth, and observable reduction in relative growth rate and motility. Moreover, the bacterial stress response promoted the biofilm formation ability of the mutant strain. The expression of the AcrAB-TolC system (acrA, acrB, and tolC) was effectively upregulated compared with the control sample when exposed to different bile salt concentrations. The findings provide valuable information for deeply understanding molecular mechanisms about the roles of tolC under bile salt stress and the prevention and control of C. malonaticus.
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Affiliation(s)
- Xin Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yaping Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yizhong Shen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Danfeng Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dengyu Liu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dexin Ou
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China.
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10
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Ding L, Jiang J, Cheng L, Wang Y, Zhang W, Li D, Xu Z, Jiang J, Gao L, Li Z. Oral Administration of Nanoiron Sulfide Supernatant for the Treatment of Gallbladder Stones with Chronic Cholecystitis. ACS APPLIED BIO MATERIALS 2021; 4:3773-3785. [PMID: 35006807 DOI: 10.1021/acsabm.0c01258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cholelithiasis with chronic cholecystitis is prevalent and threatens human health. Most cholecystitis caused by bacterial infection or biofilms is accompanied by gallstones in the clinic, making gallbladder removal the only effective solution. Here, we provide a strategy to eliminate gallstone biofilms and dissolve gallstones by oral administration of a supernatant derived from nanoscale iron sulfide (nFeS supernatant). First, by using gallstones obtained from the clinic, we simulated biofilm formation on gallstones and tested the antibacterial activity of a nFeS supernatant in vitro. We found that the supernatant kills bacteria with a 5-log reduction in viability and destroys the biofilm structure. Smashed gallstones coincubated with E. coli biofilms promote gallstone formation, while nFeS supernatant can inhibit this process. Second, by using a murine (C57BL/6) model of cholelithiasis and cholecystitis, we tested the antibacterial efficacy and therapeutic effects of nFeS supernatant on cholelithiasis in vivo. Animal experimental data show that oral administration of nFeS supernatant can reduce 60% of bacteria in the gallbladder and, remarkably, remove gallstones with 2 days of treatment compared with clinical drug combinations (chenodeoxycholid acid and ciprofloxacin). Third, by performing protein abundance analysis of L02 cells and mouse livers, we observed the changes in CYP7a1, HMGCR, and SCP2 expression, indicating that the nFeS supernatant can also regulate cholesterol metabolism to prevent gallstone formation. Finally, hematologic biochemistry analysis and high-throughput sequencing technology show that the nFeS supernatant possesses high biocompatibility. Therefore, our work demonstrates that the nFeS supernatant may be a potential regimen for the treatment of cholelithiasis and cholecystitis by oral administration.
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Affiliation(s)
- Liming Ding
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Jian Jiang
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Lu Cheng
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Yanqiu Wang
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Wei Zhang
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Dandan Li
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Zhuobin Xu
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China
| | - Jing Jiang
- CAS Engineering Laboratory for Nanozyme, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Lizeng Gao
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China.,CAS Engineering Laboratory for Nanozyme, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhennan Li
- Subei People's Hospital of Jiangsu Province, Yangzhou 225001, China
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11
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Le VVH, Biggs PJ, Wheeler D, Davies IG, Rakonjac J. Novel mechanisms of TolC-independent decreased bile-salt susceptibility in Escherichia coli. FEMS Microbiol Lett 2021; 367:5837082. [PMID: 32407499 DOI: 10.1093/femsle/fnaa083] [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: 02/19/2020] [Accepted: 05/13/2020] [Indexed: 01/24/2023] Open
Abstract
Bile salts, including sodium deoxycholate (DOC), are secreted into the intestine to aid fat digestion and contribute to antimicrobial protection. Gram-negative pathogens such as Escherichia coli, however, are highly resistant to DOC, using multiple mechanisms of which the multidrug efflux pump AcrAB-TolC is the dominant one. Given that TolC-mediated efflux masks the interaction of DOC with potential targets, we sought to identify those targets by identifying genes whose mutations cause an increase in the MIC to DOC relative to the ∆tolC parental strain, that lacks TolC-associated functional efflux pumps. Using a mutant screen, we isolated twenty independent spontaneous mutants that had a higher MICDOC than the E. coli parental ∆tolC strain. Whole genome sequencing of these mutants mapped most mutations to the ptsI or cyaA gene. Analysis of knock-out mutants and complementation showed that elimination of PtsI, a component of the carbohydrate phosphotransferase system, or one of the two key proteins involved in cAMP synthesis and signaling, adenylate cyclase (CyaA) or cAMP receptor protein (Crp) causes low-level increased resistance of a ∆tolC E. coli strain to DOC.
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Affiliation(s)
- Vuong Van Hung Le
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Patrick J Biggs
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,mEpilab, Infectious Disease Research Centre, School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - David Wheeler
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Ieuan G Davies
- New Zealand Pharmaceuticals Ltd., Palmerston North, New Zealand
| | - Jasna Rakonjac
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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12
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Olivera C, Le VVH, Davenport C, Rakonjac J. In vitro synergy of 5-nitrofurans, vancomycin and sodium deoxycholate against Gram-negative pathogens. J Med Microbiol 2021; 70. [PMID: 33448923 PMCID: PMC8346734 DOI: 10.1099/jmm.0.001304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Introduction There is an urgent need for effective therapies against bacterial infections, especially those caused by antibiotic-resistant Gram-negative pathogens. Hypothesis Synergistic combinations of existing antimicrobials show promise due to their enhanced efficacies and reduced dosages which can mitigate adverse effects, and therefore can be used as potential antibacterial therapy. Aim In this study, we sought to characterize the in vitro interaction of 5-nitrofurans, vancomycin and sodium deoxycholate (NVD) against pathogenic bacteria. Methodology The synergy of the NVD combination was investigated in terms of growth inhibition and bacterial killing using checkerboard and time-kill assays, respectively. Results Using a three-dimensional checkerboard assay, we showed that 5-nitrofurans, sodium deoxycholate and vancomycin interact synergistically in the growth inhibition of 15 out of 20 Gram-negative strains tested, including clinically significant pathogens such as carbapenemase-producing Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii, and interact indifferently against the Gram-positive strains tested. The time-kill assay further confirmed that the triple combination was bactericidal in a synergistic manner. Conclusion This study demonstrates the synergistic effect of 5-nitrofurans, sodium deoxycholate and vancomycin against Gram-negative pathogens and highlights the potential of the combination as a treatment for Gram-negative and Gram-positive infections.
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Affiliation(s)
- Catrina Olivera
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Vuong Van Hung Le
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Catherine Davenport
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Jasna Rakonjac
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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Dwivedi M, Shaw A. Implication of cation-proton antiporters (CPA) in human health and diseases causing microorganisms. Biochimie 2021; 182:85-98. [PMID: 33453344 DOI: 10.1016/j.biochi.2021.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 01/03/2021] [Accepted: 01/07/2021] [Indexed: 12/15/2022]
Abstract
Cation and protons perform a substantial role in all the organism and its homeostasis within the cells are maintained by the cation-proton antiporters (CPAs). CPA is the huge family of the membrane transporter protein throughout the plant and animal kingdom including microorganism. In human, any malfunctioning of these proteins may lead to severe diseases like hypertension, heart diseases etc and CPAs are recently proposed to be responsible for the virulent property of various pathogens including Vibrio cholerae, Yersinia pestis etc. Human Sodium-Proton exchangers (Na+/H+ exchangers, NHEs) are crucial in ion homeostasis whereas Ec-NhaA, Na + -H + Antiporters maintain a balance of Na+ and proton in E. coli, regulating pH and cell volume within the cell. These Sodium-Proton antiporters are found to be responsible for the virulence in various pathogens causing human diseases. Understanding of these CPAs may assist investigators to target such human diseases, that further may lead to establishing the effective path for therapeutics or drug designing against associated human disease. Here we have compiled all such information on CPAs and provide a systematic approach to unravel the mechanism and role of antiporter proteins in a wide range of organisms. Being involved throughout all the species, this review on cation-proton antiporters may attract the attention of many investigators and concerned researchers and will be provided with the recent detailed information on the role of CPA in human health.
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Affiliation(s)
- Manish Dwivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India.
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Diverse Physiological Functions of Cation Proton Antiporters across Bacteria and Plant Cells. Int J Mol Sci 2020; 21:ijms21124566. [PMID: 32604959 PMCID: PMC7349511 DOI: 10.3390/ijms21124566] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/17/2022] Open
Abstract
Membrane intrinsic transport systems play an important role in maintaining ion and pH homeostasis and forming the proton motive force in the cytoplasm and cell organelles. In most organisms, cation/proton antiporters (CPAs) mediate the exchange of K+, Na+ and Ca2+ for H+ across the membrane in response to a variety of environmental stimuli. The tertiary structure of the ion selective filter and the regulatory domains of Escherichia coli CPAs have been determined and a molecular mechanism of cation exchange has been proposed. Due to symbiogenesis, CPAs localized in mitochondria and chloroplasts of eukaryotic cells resemble prokaryotic CPAs. CPAs primarily contribute to keeping cytoplasmic Na+ concentrations low and controlling pH, which promotes the detoxification of electrophiles and formation of proton motive force across the membrane. CPAs in cyanobacteria and chloroplasts are regulators of photosynthesis and are essential for adaptation to high light or osmotic stress. CPAs in organellar membranes and in the plasma membrane also participate in various intracellular signal transduction pathways. This review discusses recent advances in our understanding of the role of CPAs in cyanobacteria and plant cells.
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Structure and mechanism of a redesigned multidrug transporter from the Major Facilitator Superfamily. Sci Rep 2020; 10:3949. [PMID: 32127561 PMCID: PMC7054563 DOI: 10.1038/s41598-020-60332-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/06/2020] [Indexed: 01/07/2023] Open
Abstract
The rapid increase of multidrug resistance poses urgent threats to human health. Multidrug transporters prompt multidrug resistance by exporting different therapeutics across cell membranes, often by utilizing the H+ electrochemical gradient. MdfA from Escherichia coli is a prototypical H+ -dependent multidrug transporter belonging to the Major Facilitator Superfamily. Prior studies revealed unusual flexibility in the coupling between multidrug binding and deprotonation in MdfA, but the mechanistic basis for this flexibility was obscure. Here we report the X-ray structures of a MdfA mutant E26T/D34M/A150E, wherein the multidrug-binding and protonation sites were revamped, separately bound to three different substrates at resolutions up to 2.0 Å. To validate the functional relevance of these structures, we conducted mutational and biochemical studies. Our data elucidated intermediate states during antibiotic recognition and suggested structural changes that accompany the substrate-evoked deprotonation of E26T/D34M/A150E. These findings help to explain the mechanistic flexibility in drug/H+ coupling observed in MdfA and may inspire therapeutic development to preempt efflux-mediated antimicrobial resistance.
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16
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Le VVH, Olivera C, Spagnuolo J, Davies IG, Rakonjac J. In vitro synergy between sodium deoxycholate and furazolidone against enterobacteria. BMC Microbiol 2020; 20:5. [PMID: 31906851 PMCID: PMC6945529 DOI: 10.1186/s12866-019-1668-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 11/29/2019] [Indexed: 12/11/2022] Open
Abstract
Background Antimicrobial combinations have been proven as a promising approach in the confrontation with multi-drug resistant bacterial pathogens. In the present study, we identify and characterize a synergistic interaction of broad-spectrum nitroreductase-activated prodrugs 5-nitrofurans, with a secondary bile salt, sodium deoxycholate (DOC) in growth inhibition and killing of enterobacteria. Results Using checkerboard assay, we show that combination of nitrofuran furazolidone (FZ) and DOC generates a profound synergistic effect on growth inhibition in several enterobacterial species including Escherichia coli, Salmonella enterica, Citrobacter gillenii and Klebsiella pneumoniae. The Fractional Inhibitory Concentration Index (FICI) for DOC-FZ synergy ranges from 0.125 to 0.35 that remains unchanged in an ampicillin-resistant E. coli strain containing a β-lactamase-producing plasmid. Findings from the time-kill assay further highlight the synergy with respect to bacterial killing in E. coli and Salmonella. We further characterize the mechanism of synergy in E. coli K12, showing that disruption of the tolC or acrA genes that encode components of multidrug efflux pumps causes, respectively, a complete or partial loss, of the DOC-FZ synergy. This finding indicates the key role of TolC-associated efflux pumps in the DOC-FZ synergy. Overexpression of nitric oxide-detoxifying enzyme Hmp results in a three-fold increase in FICI for DOC-FZ interaction, suggesting a role of nitric oxide in the synergy. We further demonstrate that DOC-FZ synergy is largely independent of NfsA and NfsB, the two major activation enzymes of the nitrofuran prodrugs. Conclusions This study is to our knowledge the first report of nitrofuran-deoxycholate synergy against Gram-negative bacteria, offering potential applications in antimicrobial therapeutics. The mechanism of DOC-FZ synergy involves FZ-mediated inhibition of TolC-associated efflux pumps that normally remove DOC from bacterial cells. One possible route contributing to that effect is via FZ-mediated nitric oxide production.
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Affiliation(s)
- Vuong Van Hung Le
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Catrina Olivera
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Julian Spagnuolo
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Present Address: Department of Biomedicine, University Hospital Basel, 4031, Basel, Switzerland
| | - Ieuan G Davies
- New Zealand Pharmaceuticals Ltd, Palmerston North, New Zealand
| | - Jasna Rakonjac
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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17
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Abstract
Gallstone disease is caused by multiple pathogenic factors and is common worldwide. Most studies have focused on the significance of the biliary microbiome in gallstone pathogenesis. Areas covered: In this study, the epidemiology of gallstone diseases and the existence, composition, origin, and mechanisms of the biliary microbiota were reviewed. Mechanisms involved in promoting the formation of different types of gallstones were also emphasized. The antibiotic susceptibility of the biliary microbiota is briefly discussed because it may guide clinical strategies. Expert commentary: The biliary microbiome facilitates the formation of brown pigment stones. Although glycoprotein (mucin) may be pivotal for many promoting substances to coagulate and integrate relevant components, new mechanisms involving prostaglandins, oxysterols, oxygen free radicals, and lipopolysaccharides have been discovered. Furthermore, specific bacterial species such as Helicobacter and Salmonella are involved in the pathogenesis of cholesterol gallstones. Recently, metabolomics of the biliary microbiome has been used to determine the detailed mechanisms that promote gallstone formation. Previously, the bacterial effects involved in the pathogenesis of brown pigment stones have not been analyzed in detail. Whether the administration of antibiotics is related to prophylaxis for gallstone formation and gallstone-associated infections remains unclear.
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Affiliation(s)
- Yining Wang
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Miao Qi
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Cheng Qin
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China.,b Joint Programme of Nanchang University and Queen Mary University of London , Nanchang , China
| | - Junbo Hong
- a Department of Gastroenterology , The First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi , China
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Znaidi S, van Wijlick L, Hernández‐Cervantes A, Sertour N, Desseyn J, Vincent F, Atanassova R, Gouyer V, Munro CA, Bachellier‐Bassi S, Dalle F, Jouault T, Bougnoux M, d'Enfert C. Systematic gene overexpression in Candida albicans identifies a regulator of early adaptation to the mammalian gut. Cell Microbiol 2018; 20:e12890. [PMID: 29998470 PMCID: PMC6220992 DOI: 10.1111/cmi.12890] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/12/2022]
Abstract
Candida albicans is part of the human gastrointestinal (GI) microbiota. To better understand how C. albicans efficiently establishes GI colonisation, we competitively challenged growth of 572 signature-tagged strains (~10% genome coverage), each conditionally overexpressing a single gene, in the murine gut. We identified CRZ2, a transcription factor whose overexpression and deletion respectively increased and decreased early GI colonisation. Using clues from genome-wide expression and gene-set enrichment analyses, we found that the optimal activity of Crz2p occurs under hypoxia at 37°C, as evidenced by both phenotypic and transcriptomic analyses following CRZ2 genetic perturbation. Consistent with early colonisation of the GI tract, we show that CRZ2 overexpression confers resistance to acidic pH and bile salts, suggesting an adaptation to the upper sections of the gut. Genome-wide location analyses revealed that Crz2p directly modulates the expression of many mannosyltransferase- and cell-wall protein-encoding genes, suggesting a link with cell-wall function. We show that CRZ2 overexpression alters cell-wall phosphomannan abundance and increases sensitivity to tunicamycin, suggesting a role in protein glycosylation. Our study reflects the powerful use of gene overexpression as a complementary approach to gene deletion to identify relevant biological pathways involved in C. albicans interaction with the host environment.
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Affiliation(s)
- Sadri Znaidi
- Institut Pasteur, INRAUnité Biologie et Pathogénicité FongiquesParisFrance
- Institut Pasteur de Tunis, University of Tunis El ManarLaboratoire de Microbiologie Moléculaire, Vaccinologie et Développement BiotechnologiqueTunisTunisia
| | - Lasse van Wijlick
- Institut Pasteur, INRAUnité Biologie et Pathogénicité FongiquesParisFrance
| | | | - Natacha Sertour
- Institut Pasteur, INRAUnité Biologie et Pathogénicité FongiquesParisFrance
| | - Jean‐Luc Desseyn
- Lille Inflammation Research International Center, UMR 995 InsermUniversité Lille 2, Faculté de MédecineLilleFrance
| | | | | | - Valérie Gouyer
- Lille Inflammation Research International Center, UMR 995 InsermUniversité Lille 2, Faculté de MédecineLilleFrance
| | - Carol A. Munro
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical SciencesUniversity of AberdeenAberdeenUK
| | | | - Frédéric Dalle
- UMR 1347Université de BourgogneDijonFrance
- Centre Hospitalier UniversitaireService de Parasitologie MycologieDijonFrance
| | - Thierry Jouault
- Lille Inflammation Research International Center, UMR 995 InsermUniversité Lille 2, Faculté de MédecineLilleFrance
| | - Marie‐Elisabeth Bougnoux
- Institut Pasteur, INRAUnité Biologie et Pathogénicité FongiquesParisFrance
- Laboratoire de Parasitologie‐Mycologie, Service de Microbiologie, Hôpital Necker‐Enfants MaladesUniversité Paris Descartes, Faculté de MédecineParisFrance
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Kato S, Tobe H, Matsubara H, Sawada M, Sasaki Y, Fukiya S, Morita N, Yokota A. The membrane phospholipid cardiolipin plays a pivotal role in bile acid adaptation by Lactobacillus gasseri JCM1131 T. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:403-412. [PMID: 29883797 DOI: 10.1016/j.bbalip.2018.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/17/2018] [Accepted: 06/03/2018] [Indexed: 01/26/2023]
Abstract
Bile acids exhibit strong antimicrobial activity as natural detergents, and are involved in lipid digestion and absorption. We investigated the mechanism of bile acid adaptation in Lactobacillus gasseri JCM1131T. Exposure to sublethal concentrations of cholic acid (CA), a major bile acid in humans, resulted in development of resistance to otherwise-lethal concentrations of CA by this intestinal lactic acid bacterium. As this adaptation was accompanied by decreased cell-membrane damage, we analyzed the membrane lipid composition of L. gasseri. Although there was no difference in the proportions of glycolipids (~70%) and phospholipids (~20%), adaptation resulted in an increased abundance of long-sugar-chain glycolipids and a 100% increase in cardiolipin (CL) content (to ~50% of phospholipids) at the expense of phosphatidylglycerol (PG). In model vesicles, the resistance of PG vesicles to solubilization by CA increased with increasing CL/PG ratio. Deletion of the two putative CL synthase genes, the products of which are responsible for CL synthesis from PG, decreased the CL content of the mutants, but did not affect their ability to adapt to CA. Exposure to CA restored the CL content of the two single-deletion mutants, likely due to the activities of the remaining CL synthase. In contrast, the CL content of the double-deletion mutant was not restored, and the lipid composition was modified such that PG predominated (~45% of total lipids) at the expense of glycolipids. Therefore, CL plays important roles in bile acid resistance and maintenance of the membrane lipid composition in L. gasseri.
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Affiliation(s)
- Shinji Kato
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
| | - Haruhi Tobe
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
| | - Hiroki Matsubara
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
| | - Mariko Sawada
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
| | - Yasuko Sasaki
- Laboratory of Fermented Foods, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan.
| | - Satoru Fukiya
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
| | - Naoki Morita
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Hokkaido 062-8517, Japan.
| | - Atsushi Yokota
- Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
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20
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Petronella N, Ronholm J. The mechanisms that regulate Vibrio parahaemolyticus virulence gene expression differ between pathotypes. Microb Genom 2018; 4. [PMID: 29813014 PMCID: PMC6096935 DOI: 10.1099/mgen.0.000182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Most Vibrio parahaemolyticus isolates found in marine environments are non-pathogenic; however, certain lineages have acquired genomic pathogenicity islands (PAIs) that enable these isolates to cause human illness. The V. parahaemolyticus PAI contains one or both of two toxins: thermostable direct haemolysin (TDH) or TDH-related haemolysin (TRH) and type III secretion system 2 (T3SS2). Recently, a few V. parahaemolyticus isolates that do not have this PAI were obtained from clinical samples, and there has been interest in determining whether these isolates possess novel virulence factors. In this investigation, we have selected four V. parahaemolyticus isolates: a canonical pathogenic strain containing TDH, TRH and T3SS2; two strains from clinical cases which do not contain a PAI; and an environmental isolate which also does not contain a PAI. For each isolate, we analyzed differential gene expression after crude bile exposure. Several enteric bacterial pathogens are known to use bile as a signal to enhance virulence gene expression. We have shown that in the tdh-positive trh-positive pathotype gene virulence gene expression was not up-regulated in response to crude bile, strongly indicating that the current dogma of virulence gene regulation in V. parahaemolyticus needs to be revisited and separately investigated for each pathotype. In addition, we have created a list of genes of interest that were up-regulated in the non-canonical pathotypes which may contribute to virulence in these isolates.
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Affiliation(s)
- Nicholas Petronella
- 1Biostatistics and Modelling Division, Bureau of Food Surveillance and Science Integration, Food Directorate, Health Canada, Ottawa, ON, Canada
| | - Jennifer Ronholm
- 2Department of Animal Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada.,3Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne-de-Bellevue, QC, Canada
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21
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Zomot E, Yardeni EH, Vargiu AV, Tam HK, Malloci G, Ramaswamy VK, Perach M, Ruggerone P, Pos KM, Bibi E. A New Critical Conformational Determinant of Multidrug Efflux by an MFS Transporter. J Mol Biol 2018. [PMID: 29530612 DOI: 10.1016/j.jmb.2018.02.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Secondary multidrug (Mdr) transporters utilize ion concentration gradients to actively remove antibiotics and other toxic compounds from cells. The model Mdr transporter MdfA from Escherichia coli exchanges dissimilar drugs for protons. The transporter should open at the cytoplasmic side to enable access of drugs into the Mdr recognition pocket. Here we show that the cytoplasmic rim around the Mdr recognition pocket represents a previously overlooked important regulatory determinant in MdfA. We demonstrate that increasing the positive charge of the electrically asymmetric rim dramatically inhibits MdfA activity and sometimes even leads to influx of planar, positively charged compounds, resulting in drug sensitivity. Our results suggest that unlike the mutants with the electrically modified rim, the membrane-embedded wild-type MdfA exhibits a significant probability of an inward-closed conformation, which is further increased by drug binding. Since MdfA binds drugs from its inward-facing environment, these results are intriguing and raise the possibility that the transporter has a sensitive, drug-induced conformational switch, which favors an inward-closed state.
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Affiliation(s)
- Elia Zomot
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eliane Hadas Yardeni
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Heng-Keat Tam
- Institute of Biochemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | | | - Michal Perach
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Eitan Bibi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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22
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Clamping down on drugs: the Escherichia coli multidrug efflux protein MdtM. Res Microbiol 2017; 169:461-467. [PMID: 28962921 DOI: 10.1016/j.resmic.2017.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 11/22/2022]
Abstract
Multidrug resistance is principally a consequence of the active transport of drugs out of the cell by proteins that are integral membrane transporters. In the following review, we present a synthesis of current understanding of the Escherichia coli multidrug resistance transporter, MdtM, a 410 amino acid residue protein that belongs to the large and ubiquitous major facilitator superfamily (MFS).
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23
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Yardeni EH, Zomot E, Bibi E. The fascinating but mysterious mechanistic aspects of multidrug transport by MdfA from Escherichia coli. Res Microbiol 2017; 169:455-460. [PMID: 28951231 DOI: 10.1016/j.resmic.2017.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/24/2017] [Accepted: 09/13/2017] [Indexed: 10/18/2022]
Abstract
MdfA is an interesting member of a large group of secondary multidrug (Mdr) transporters. Through genetic, biochemical and biophysical studies of MdfA, many challenging aspects of the multidrug transport phenomenon have been addressed. This includes its ability to interact with chemically unrelated drugs and how it utilizes energy to drive efflux of compounds that are not only structurally, but also electrically, different. Admittedly, however, despite all efforts and a recent pioneering structural contribution, several important mechanistic issues of the promiscuous capabilities of MdfA still seek better molecular and dynamic understanding.
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Affiliation(s)
- Eliane H Yardeni
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Elia Zomot
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Bibi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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24
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Transcriptomic Analysis Reveals Genes Mediating Salt Tolerance through Calcineurin/CchA-Independent Signaling in Aspergillus nidulans. BIOMED RESEARCH INTERNATIONAL 2017; 2017:4378627. [PMID: 28904958 PMCID: PMC5585587 DOI: 10.1155/2017/4378627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/01/2017] [Accepted: 07/10/2017] [Indexed: 01/11/2023]
Abstract
Adaptation to changes in the environment is crucial for the viability of all organisms. Although the importance of calcineurin in the stress response has been highlighted in filamentous fungi, little is known about the involvement of ion-responsive genes and pathways in conferring salt tolerance without calcium signaling. In this study, high-throughput RNA-seq was used to investigate salt stress-induced genes in the parent, ΔcnaB, and ΔcnaBΔcchA strains of Aspergillus nidulans, which differ greatly in salt adaption. In total, 2,884 differentially expressed genes including 1,382 up- and 1,502 downregulated genes were identified. Secondary transporters, which were upregulated to a greater extent in ΔcnaBΔcchA than in the parent or ΔcnaB strains, are likely to play important roles in response to salt stress. Furthermore, 36 genes were exclusively upregulated in the ΔcnaBΔcchA under salt stress. Functional analysis of differentially expressed genes revealed that genes involved in transport, heat shock protein binding, and cell division processes were exclusively activated in ΔcnaBΔcchA. Overall, our findings reveal that secondary transporters and stress-responsive genes may play crucial roles in salt tolerance to bypass the requirement for the CchA-calcineurin pathway, contributing to a deeper understanding of the mechanisms that influence fungal salt stress adaption in Aspergillus.
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25
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Rahman T, Yarnall B, Doyle DA. Efflux drug transporters at the forefront of antimicrobial resistance. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:647-653. [PMID: 28710521 PMCID: PMC5599465 DOI: 10.1007/s00249-017-1238-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/19/2017] [Accepted: 06/30/2017] [Indexed: 12/12/2022]
Abstract
Bacterial antibiotic resistance is rapidly becoming a major world health consideration. To combat antibiotics, microorganisms employ their pre-existing defence mechanisms that existed long before man’s discovery of antibiotics. Bacteria utilise levels of protection that range from gene upregulation, mutations, adaptive resistance, and production of resistant phenotypes (persisters) to communal behaviour, as in swarming and the ultimate defence of a biofilm. A major part of all of these responses involves the use of antibiotic efflux transporters. At the single cell level, it is becoming apparent that the use of efflux pumps is the first line of defence against an antibiotic, as these pumps decrease the intracellular level of antibiotic while the cell activates the various other levels of protection. This frontline of defence involves a coordinated network of efflux transporters. In the future, inhibition of this efflux transporter network, as a target for novel antibiotic therapy, will require the isolation and then biochemical/biophysical characterisation of each pump against all known and new antibiotics. This depth of knowledge is required so that we can fully understand and tackle the mechanisms of developing antimicrobial resistance.
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Affiliation(s)
- Tahmina Rahman
- University of Southampton, Biological Sciences, Highfield Campus, Southampton, SO17 1BJ, UK.,Wessex Kidney Centre, Queen Alexandra Hospital, Cosham, Portsmouth, PO6 3LY, UK
| | - Benjamin Yarnall
- University of Southampton, Biological Sciences, Highfield Campus, Southampton, SO17 1BJ, UK
| | - Declan A Doyle
- University of Southampton, Biological Sciences, Highfield Campus, Southampton, SO17 1BJ, UK.
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26
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Global transcriptional response of Escherichia coli MG1655 cells exposed to the oxygenated monoterpenes citral and carvacrol. Int J Food Microbiol 2017. [PMID: 28644990 DOI: 10.1016/j.ijfoodmicro.2017.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
DNA microarrays were used to study the mechanism of bacterial inactivation by carvacrol and citral. After 10-min treatments of Escherichia coli MG1655 cells with 100 and 50ppm of carvacrol and citral, 76 and 156 genes demonstrated significant transcriptional differences (p≤0.05), respectively. Among the up-regulated genes after carvacrol treatment, we found gene coding for multidrug efflux pumps (acrA, mdtM), genes related to phage shock response (pspA, pspB, pspC, pspD, pspF and pspG), biosynthesis of arginine (argC, argG, artJ), and purine nucleotides (purC, purM). In citral-treated cells, transcription of purH and pyrB and pyrI was 2 times higher. Deletion of several differentially expressed genes confirmed the role of ygaV, yjbO, pspC, sdhA, yejG and ygaV in the mechanisms of E. coli inactivation by carvacrol and citral. These results would indicate that citral and carvacrol treatments cause membrane damage and activate metabolism through the production of nucleotides required for DNA and RNA synthesis and metabolic processes. Comparative transcriptomics of the response of E. coli to a heat treatment, which caused a significant change of the transcription of 1422 genes, revealed a much weaker response to both individual constituents of essential oils (ICs).·Thus, inactivation by citral or carvacrol was not multitarget in nature.
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Labarbuta P, Duckett K, Botting CH, Chahrour O, Malone J, Dalton JP, Law CJ. Recombinant vacuolar iron transporter family homologue PfVIT from human malaria-causing Plasmodium falciparum is a Fe 2+/H +exchanger. Sci Rep 2017; 7:42850. [PMID: 28198449 PMCID: PMC5309874 DOI: 10.1038/srep42850] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/18/2017] [Indexed: 02/08/2023] Open
Abstract
Vacuolar iron transporters (VITs) are a poorly understood family of integral membrane proteins that can function in iron homeostasis via sequestration of labile Fe2+ into vacuolar compartments. Here we report on the heterologous overexpression and purification of PfVIT, a vacuolar iron transporter homologue from the human malaria-causing parasite Plasmodium falciparum. Use of synthetic, codon-optimised DNA enabled overexpression of functional PfVIT in the inner membrane of Escherichia coli which, in turn, conferred iron tolerance to the bacterial cells. Cells that expressed PfVIT had decreased levels of total cellular iron compared with cells that did not express the protein. Qualitative transport assays performed on inverted vesicles enriched with PfVIT revealed that the transporter catalysed Fe2+/H+ exchange driven by the proton electrochemical gradient. Furthermore, the PfVIT transport function in this system did not require the presence of any Plasmodium-specific factor such as post-translational phosphorylation. PfVIT purified as a monomer and, as measured by intrinsic protein fluorescence quenching, bound Fe2+ in detergent solution with low micromolar affinity. This study of PfVIT provides material for future detailed biochemical, biophysical and structural studies to advance understanding of the vacuolar iron transporter family of membrane proteins from important human pathogens.
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Affiliation(s)
- Paola Labarbuta
- School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, Belfast BT9 7BL, United Kingdom
| | - Katie Duckett
- School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, Belfast BT9 7BL, United Kingdom
| | - Catherine H Botting
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Osama Chahrour
- Spectroscopy Group, Analytical Services, Almac, 20 Seagoe Industrial Estate, Craigavon BT63 5QD, United Kingdom
| | - John Malone
- Spectroscopy Group, Analytical Services, Almac, 20 Seagoe Industrial Estate, Craigavon BT63 5QD, United Kingdom
| | - John P Dalton
- School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, Belfast BT9 7BL, United Kingdom
| | - Christopher J Law
- School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, Belfast BT9 7BL, United Kingdom
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Yücel O, Drees S, Jagmann N, Patschkowski T, Philipp B. An unexplored pathway for degradation of cholate requires a 7α-hydroxysteroid dehydratase and contributes to a broad metabolic repertoire for the utilization of bile salts in N
ovosphingobium
sp. strain Chol11. Environ Microbiol 2016; 18:5187-5203. [DOI: 10.1111/1462-2920.13534] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/15/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Onur Yücel
- Westfälische Wilhelms-Universität Münster Institut für Molekulare Mikrobiologie und Biotechnologie; Münster 48149 Germany
| | - Steffen Drees
- Westfälische Wilhelms-Universität Münster Institut für Molekulare Mikrobiologie und Biotechnologie; Münster 48149 Germany
| | - Nina Jagmann
- Westfälische Wilhelms-Universität Münster Institut für Molekulare Mikrobiologie und Biotechnologie; Münster 48149 Germany
| | - Thomas Patschkowski
- Centrum für Biotechnologie - CeBiTec; Universität Bielefeld; Bielefeld 33501 Germany
| | - Bodo Philipp
- Westfälische Wilhelms-Universität Münster Institut für Molekulare Mikrobiologie und Biotechnologie; Münster 48149 Germany
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29
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Liu M, Heng J, Gao Y, Wang X. Crystal structures of MdfA complexed with acetylcholine and inhibitor reserpine. BIOPHYSICS REPORTS 2016; 2:78-85. [PMID: 28018966 PMCID: PMC5138259 DOI: 10.1007/s41048-016-0028-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/15/2016] [Indexed: 11/24/2022] Open
Abstract
The DHA12 family of transporters contains a number of prokaryotic and eukaryote membrane proteins. Some of these proteins share conserved sites intrinsic to substrate recognition, structural stabilization and conformational changes. For this study, we chose the MdfA transporter as a model DHA12 protein to study some general characteristics of the vesicular neurotransmitter transporters (VNTs), which all belong to the DHA12 family. Two crystal structures were produced for E. coli MdfA, one in complex with acetylcholine and the other with potential reserpine, which are substrate and inhibitor of VNTs, respectively. These structures show that the binding sites of these two molecules are different. The Ach-binding MfdA is mainly dependent on D34, while reserpine-binding site is more hydrophobic. Based on sequence alignment and homology modelling, we were able to provide mechanistic insights into the association between the inhibition and the conformational changes of these transporters.
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Affiliation(s)
- Ming Liu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457 China
| | - Jie Heng
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yuan Gao
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Xianping Wang
- National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
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30
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Hernando-Amado S, Blanco P, Alcalde-Rico M, Corona F, Reales-Calderón JA, Sánchez MB, Martínez JL. Multidrug efflux pumps as main players in intrinsic and acquired resistance to antimicrobials. Drug Resist Updat 2016; 28:13-27. [PMID: 27620952 DOI: 10.1016/j.drup.2016.06.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/23/2016] [Indexed: 12/31/2022]
Abstract
Multidrug efflux pumps constitute a group of transporters that are ubiquitously found in any organism. In addition to other functions with relevance for the cell physiology, efflux pumps contribute to the resistance to compounds used for treating different diseases, including resistance to anticancer drugs, antibiotics or antifungal compounds. In the case of antimicrobials, efflux pumps are major players in both intrinsic and acquired resistance to drugs currently in use for the treatment of infectious diseases. One important aspect not fully explored of efflux pumps consists on the identification of effectors able to induce their expression. Indeed, whereas the analysis of clinical isolates have shown that mutants overexpressing these resistance elements are frequently found, less is known on the conditions that may trigger expression of efflux pumps, hence leading to transient induction of resistance in vivo, a situation that is barely detectable using classical susceptibility tests. In the current article we review the structure and mechanisms of regulation of the expression of bacterial and fungal efflux pumps, with a particular focus in those for which a role in clinically relevant resistance has been reported.
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Affiliation(s)
- Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Paula Blanco
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Manuel Alcalde-Rico
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Fernando Corona
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Jose A Reales-Calderón
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - María B Sánchez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
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31
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Insight into determinants of substrate binding and transport in a multidrug efflux protein. Sci Rep 2016; 6:22833. [PMID: 26961153 PMCID: PMC4785361 DOI: 10.1038/srep22833] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/24/2016] [Indexed: 11/09/2022] Open
Abstract
Multidrug resistance arising from the activity of integral membrane transporter proteins presents a global public health threat. In bacteria such as Escherichia coli, transporter proteins belonging to the major facilitator superfamily make a considerable contribution to multidrug resistance by catalysing efflux of myriad structurally and chemically different antimicrobial compounds. Despite their clinical relevance, questions pertaining to mechanistic details of how these promiscuous proteins function remain outstanding, and the role(s) played by individual amino acid residues in recognition, binding and subsequent transport of different antimicrobial substrates by multidrug efflux members of the major facilitator superfamily requires illumination. Using in silico homology modelling, molecular docking and mutagenesis studies in combination with substrate binding and transport assays, we identified several amino acid residues that play important roles in antimicrobial substrate recognition, binding and transport by Escherichia coli MdtM, a representative multidrug efflux protein of the major facilitator superfamily. Furthermore, our studies suggested that ‘aromatic clamps’ formed by tyrosine and phenylalanine residues located within the substrate binding pocket of MdtM may be important for antimicrobial substrate recognition and transport by the protein. Such ‘clamps’ may be a structurally and functionally important feature of all major facilitator multidrug efflux proteins.
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32
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Hay AJ, Zhu J. In Sickness and in Health: The Relationships Between Bacteria and Bile in the Human Gut. ADVANCES IN APPLIED MICROBIOLOGY 2016; 96:43-64. [PMID: 27565580 DOI: 10.1016/bs.aambs.2016.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Colonization of a human host with a commensal microbiota has a complex interaction in which bacterial communities provide numerous health benefits to the host. An equilibrium between host and microbiota is kept in check with the help of biliary secretions by the host. Bile, composed primarily of bile salts, promotes digestion. It also provides a barrier between host and bacteria. After bile salts are synthesized in the liver, they are stored in the gallbladder to be released after food intake. The set of host-secreted bile salts is modified by the resident bacteria. Because bile salts are toxic to bacteria, an equilibrium of modified bile salts is reached that allows commensal bacteria to survive, yet rebuffs invading pathogens. In addition to direct toxic effects on cells, bile salts maintain homeostasis as signaling molecules, tuning the immune system. To cause disease, gram-negative pathogenic bacteria have shared strategies to survive this harsh environment. Through exclusion of bile, efflux of bile, and repair of bile-induced damage, these pathogens can successfully disrupt and outcompete the microbiota to activate virulence factors.
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Affiliation(s)
- A J Hay
- University of Pennsylvania, Philadelphia, PA, United States
| | - J Zhu
- University of Pennsylvania, Philadelphia, PA, United States
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33
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Role of the Tet38 Efflux Pump in Staphylococcus aureus Internalization and Survival in Epithelial Cells. Infect Immun 2015; 83:4362-72. [PMID: 26324534 DOI: 10.1128/iai.00723-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/24/2015] [Indexed: 12/22/2022] Open
Abstract
We previously identified the protein Tet38 as a chromosomally encoded efflux pump of Staphylococcus aureus that confers resistance to tetracycline and certain unsaturated fatty acids. Tet38 also contributes to mouse skin colonization. In this study, we discovered a novel regulator of tet38, named tetracycline regulator 21 (TetR21), that bound specifically to the tet38 promoter and repressed pump expression. A ΔtetR21 mutant showed a 5-fold increase in tet38 transcripts and an 8-fold increase in resistance to tetracycline and fatty acids. The global regulator MgrA bound to the tetR21 promoter and indirectly repressed the expression of tet38. To further assess the full role of Tet38 in S. aureus adaptability, we tested its effect on host cell invasion using A549 (lung) and HMEC-1 (heart) cell lines. We used S. aureus RN6390, its Δtet38, ΔtetR21, and ΔmgrA mutants, and a Δtet38 ΔtetR21 double mutant. After 2 h of contact, the Δtet38 mutant was internalized in 6-fold-lower numbers than RN6390 in A549 and HMEC-1 cells, and the ΔtetR21 mutant was internalized in 2-fold-higher numbers than RN6390. A slight increase of 1.5-fold in internalization was found for the ΔmgrA mutant. The growth patterns of RN6390 and the ΔmgrA and ΔtetR21 mutants within A549 cells were similar, while no growth was observed for the Δtet38 mutant. These data indicate that the Tet38 efflux pump is regulated by TetR21 and contributes to the ability of S. aureus to internalize and replicate within epithelial cells.
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34
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Heng J, Zhao Y, Liu M, Liu Y, Fan J, Wang X, Zhao Y, Zhang XC. Substrate-bound structure of the E. coli multidrug resistance transporter MdfA. Cell Res 2015; 25:1060-73. [PMID: 26238402 DOI: 10.1038/cr.2015.94] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/02/2015] [Accepted: 05/07/2015] [Indexed: 12/12/2022] Open
Abstract
Multidrug resistance is a serious threat to public health. Proton motive force-driven antiporters from the major facilitator superfamily (MFS) constitute a major group of multidrug-resistance transporters. Currently, no reports on crystal structures of MFS antiporters in complex with their substrates exist. The E. coli MdfA transporter is a well-studied model system for biochemical analyses of multidrug-resistance MFS antiporters. Here, we report three crystal structures of MdfA-ligand complexes at resolutions up to 2.0 Å, all in the inward-facing conformation. The substrate-binding site sits proximal to the conserved acidic residue, D34. Our mutagenesis studies support the structural observations of the substrate-binding mode and the notion that D34 responds to substrate binding by adjusting its protonation status. Taken together, our data unveil the substrate-binding mode of MFS antiporters and suggest a mechanism of transport via this group of transporters.
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Affiliation(s)
- Jie Heng
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Zhao
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ming Liu
- College of Biotechnology, Tianjin University of Science and Technology, 29 13th Street, TEDA, Tianjin 300457, China
| | - Yue Liu
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Junping Fan
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xianping Wang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Yongfang Zhao
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
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35
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Influence of the yjiL-mdtM Gene Cluster on the Antibacterial Activity of Proline-Rich Antimicrobial Peptides Overcoming Escherichia coli Resistance Induced by the Missing SbmA Transporter System. Antimicrob Agents Chemother 2015; 59:5992-8. [PMID: 26169420 DOI: 10.1128/aac.01307-15] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/08/2015] [Indexed: 12/23/2022] Open
Abstract
In view of increasing health threats from multiresistant pathogens, antimicrobial peptides (AMPs) and, specifically, proline-rich AMPs (PrAMPs) have been investigated in animal models. PrAMPs enter bacteria via the ABC transporter SbmA and inhibit intracellular targets. We used phage transduction (Tn10 insertion) to screen by random mutagenesis for alternative uptake mechanisms for analogs of apidaecin 1b, a honeybee-derived PrAMP. All 24 apidaecin-resistant mutants had the Tn10 insertion in the sbmA gene. These sbmA::Tn10 insertion mutants and the Escherichia coli BW25113 ΔsbmA (JW0368) strain were still susceptible to the bactenecin PrAMP Bac7(1-35) and oncocin PrAMPs Onc18 and Onc112, as well as to Chex1-Arg20, despite significantly reduced internalizations. In a second round of random mutagenesis, the remaining susceptibility was linked to the yjiL-mdtM gene cluster. E. coli BW25113 and its ΔyjiL null mutant (JW5785) were equally susceptible to all PrAMPs tested, whereas the BW25113 ΔmdtM mutant was less susceptible to oncocins. The JW0368 yjiL::Tn10 transposon mutant (BS2) was resistant to all short PrAMPs and susceptible only to full-length Bac7 and A3-APO. Interestingly, PrAMPs appear to enter bacteria via MdtM, a multidrug resistance transporter (drug/H(+) antiporter) of the major facilitator superfamily (MFS) that can efflux antibiotics, biocides, and bile salts. In conclusion, PrAMPs enter bacteria via ABC and MFS transporters that efflux antibiotics and cytotoxic compounds from the cytoplasm to the periplasm.
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36
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 899] [Impact Index Per Article: 99.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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37
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Membrane transporter engineering in industrial biotechnology and whole cell biocatalysis. Trends Biotechnol 2015; 33:237-46. [DOI: 10.1016/j.tibtech.2015.02.001] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/15/2015] [Accepted: 02/02/2015] [Indexed: 02/06/2023]
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38
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Purification of a Multidrug Resistance Transporter for Crystallization Studies. Antibiotics (Basel) 2015; 4:113-35. [PMID: 27025617 PMCID: PMC4790320 DOI: 10.3390/antibiotics4010113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/23/2015] [Accepted: 02/25/2015] [Indexed: 01/12/2023] Open
Abstract
Crystallization of integral membrane proteins is a challenging field and much effort has been invested in optimizing the overexpression and purification steps needed to obtain milligram amounts of pure, stable, monodisperse protein sample for crystallography studies. Our current work involves the structural and functional characterization of the Escherichia coli multidrug resistance transporter MdtM, a member of the major facilitator superfamily (MFS). Here we present a protocol for isolation of MdtM to increase yields of recombinant protein to the milligram quantities necessary for pursuit of structural studies using X-ray crystallography. Purification of MdtM was enhanced by introduction of an elongated His-tag, followed by identification and subsequent removal of chaperonin contamination. For crystallization trials of MdtM, detergent screening using size exclusion chromatography determined that decylmaltoside (DM) was the shortest-chain detergent that maintained the protein in a stable, monodispersed state. Crystallization trials of MdtM performed using the hanging-drop diffusion method with commercially available crystallization screens yielded 3D protein crystals under several different conditions. We contend that the purification protocol described here may be employed for production of high-quality protein of other multidrug efflux members of the MFS, a ubiquitous, physiologically and clinically important class of membrane transporters.
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39
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Zhang Y, Liu J, Tang K, Yu M, Coenye T, Zhang XH. Genome analysis of Flaviramulus ichthyoenteri Th78(T) in the family Flavobacteriaceae: insights into its quorum quenching property and potential roles in fish intestine. BMC Genomics 2015; 16:38. [PMID: 25652846 PMCID: PMC4324048 DOI: 10.1186/s12864-015-1275-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 01/22/2015] [Indexed: 12/04/2022] Open
Abstract
Background Intestinal microbes play significant roles in fish and can be possibly used as probiotics in aquaculture. In our previous study, Flaviramulus ichthyoenteri Th78T, a novel species in the family Flavobacteriaceae, was isolated from fish intestine and showed strong quorum quenching (QQ) ability. To identify the QQ enzymes in Th78T and explore the potential roles of Th78T in fish intestine, we sequenced the genome of Th78T and performed extensive genomic analysis. Results An N-acyl homoserine lactonase FiaL belonging to the metallo-β-lactamase superfamily was identified and the QQ activity of heterologously expressed FiaL was confirmed in vitro. FiaL has relatively little similarity to the known lactonases (25.2 ~ 27.9% identity in amino acid sequence). Various digestive enzymes including alginate lyases and lipases can be produced by Th78T, and enzymes essential for production of B vitamins such as biotin, riboflavin and folate are predicted. Genes encoding sialic acid lyases, sialidases, sulfatases and fucosidases, which contribute to utilization of mucus, are present in the genome. In addition, genes related to response to different stresses and gliding motility were also identified. Comparative genome analysis shows that Th78T has more specific genes involved in carbohydrate transport and metabolism compared to other two isolates in Flavobacteriaceae, both isolated from sediments. Conclusions The genome of Th78T exhibits evident advantages for this bacterium to survive in the fish intestine, including production of QQ enzyme, utilization of various nutrients available in the intestine as well as the ability to produce digestive enzymes and vitamins, which also provides an application prospect of Th78T to be used as a probiotic in aquaculture. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1275-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yunhui Zhang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, P.R. China.
| | - Jiwen Liu
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, P.R. China.
| | - Kaihao Tang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, P.R. China.
| | - Min Yu
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, P.R. China.
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, 9000, Gent, Belgium.
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, P.R. China.
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40
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Holdsworth S, Law C. Measurement of Proton-driven Antiport in Escherichia coli. Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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41
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Holdsworth S, Law C. Measurement of the Electrogenicity of Bile Salt/H+ Antiport in Escherichia coli. Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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