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Xiao X, Li J, Wang X, Ding L, Shen S, Liu T, Ren Z, Luo X. Salinity-mediated enhancement of quaternary ammonium compounds resistance and removal in endophytic bacteria LSE01. ENVIRONMENTAL RESEARCH 2024; 251:118688. [PMID: 38493855 DOI: 10.1016/j.envres.2024.118688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/28/2024] [Accepted: 03/10/2024] [Indexed: 03/19/2024]
Abstract
The widespread usage of quaternary ammonium compounds (QACs) as disinfectants during the COVID-19 pandemic poses significant environmental risks, such as toxicity to organisms and the emergence of superbugs. In this study, different inorganic salts (NaCl, KCl, CaCl2, MgCl2) were used to induce endophytes LSE01 isolated from hyperaccumulating plants. After five generations of cultivation under 80 g/L NaCl, the minimum inhibitory concentration (MIC) of LSE01 to QACs increased by about 3-fold, while its degradation extent increased from 8% to 84% for C12BDMA-Cl and 5%-89% for C14BDMA-Cl. Transmission electron microscopy (TEM) and three-dimensional fluorescence spectra indicated that the cells induced by high concentration of salt caused plasmolysis and secreted more bound extracellular polymeric substances (B-EPS); these changes are likely to be an important reason for the observed increased resistance and enhanced degradation extent of LSE01 to QACs. Our findings suggest that salt-induction could be an effective way to enhance the resistance and removal of toxic organic pollutants by functional microorganisms.
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Affiliation(s)
- Xiao Xiao
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China
| | - Junjie Li
- The School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR China; China National Gold Group Jiangxi Mining Co., Ltd, Shangrao 334213, PR China
| | - Xiaotong Wang
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China
| | - Lin Ding
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China.
| | - Shengju Shen
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China
| | - Ting Liu
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China
| | - Zhong Ren
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China
| | - Xubiao Luo
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, PR China; National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resources Utilization, Nanchang Hangkong University, Nanchang 330063, PR China.
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2
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Li B, Jeon MK, Li X, Yan T. Differential impacts of salinity on antibiotic resistance genes during cattle manure stockpiling are linked to mobility potentials revealed by metagenomic sequencing. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130590. [PMID: 37055994 DOI: 10.1016/j.jhazmat.2022.130590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 11/09/2022] [Accepted: 12/08/2022] [Indexed: 06/19/2023]
Abstract
Livestock manure is an important source of antibiotic resistance genes (ARGs), and its salinity level can change during stockpiling. To understand how the salinity changes affect the fate of ARGs, cattle manure was adjusted of salinity and stockpiled in laboratory microcosms at low (0.3% salt), moderate (3.0%) and high salinity levels (10.0%) for 44 days. Amongst the five ARGs (tetO, blaTEM, sul1, tetM, and ermB) and the first-class integrase (intI1) monitored by qPCR, the relative abundance of tetO and blaTEM exhibited no clear trend in response to salinity levels, while that of sul1, tetM, ermB and intI1 showed clear downward trends over time at the lower salinity levels (0.3% and 3%) but not at the high salinity level (10%). Metagenomic contig construction of cattle manure samples revealed that sul1, tetM and ermB genes were more likely to associate with mobile genetic elements (MGEs) than tetO and blaTEM, suggesting that their slower decay at higher salinity levels was either caused by horizontal gene transfer or co-selection of ARGs and osmotic stress resistant determinants. Further analysis of metagenomic contigs showed that osmotic stress resistance can also be located on MGEs or in conjunction with ARGs.
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Affiliation(s)
- Bo Li
- Department of Civil and Environmental Engineering, Water Resources Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, United States
| | - Min Ki Jeon
- Department of Civil and Environmental Engineering, Water Resources Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, United States
| | - Xu Li
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Tao Yan
- Department of Civil and Environmental Engineering, Water Resources Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, United States; Water Resources Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, United States.
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3
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Xu Y, You G, Yin J, Zhang M, Peng D, Xu J, Yang S, Hou J. Salt tolerance evolution facilitates antibiotic resistome in soil microbiota: Evidences from dissemination evaluation, hosts identification and co-occurrence exploration. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 317:120830. [PMID: 36481466 DOI: 10.1016/j.envpol.2022.120830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/26/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Salinity is considered as one of the vital factors affecting the profiles of antibiotic resistance genes (ARGs) in soils, whereby its roles in shaping the antibiotic resistome were still poorly understood. Here, metagenomic analysis was conducted to track the ARGs distributions and dissemination in soils during salt accumulation and desalinization processes. Neutral-salt accumulation for 45 and 90 days significantly increased the relative abundances of ARGs and mobile genetic elements (MGEs) carrying antibiotic resistance contigs (ARCs). The ARGs within antibiotic efflux and target protection families primarily carried by Streptomyces, Nocardioides, Rhodanobacter and Monashia were largely enriched by salinity. The ARGs subtypes of the resistance-nodulation-division (RND) family, ATP-binding cassette (ABC) family, rRNA methyltransferase and other efflux were closely associated with MGEs, contributing to the enrichment of ARGs. Moreover, the ARGs subtypes and transposons were genetically linked with the salt-tolerance mechanisms of organic osmolyte transporters and K+ uptake proteins on the same ARC, demonstrating the coselection of ARGs and halotolerant genes. Furthermore, the antibiotic resistome could recover to a normal state after the prolonged incubation by alleviating salt stress. Nevertheless, the acquisition of ARGs by opportunistic pathogens after salt treatment was increased, serving to prioritize further efforts on the health risks correlated with resistance propagation and human exposure in saline soils.
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Affiliation(s)
- Yi Xu
- College of Agricultural Science and Engineering, Hohai University, Nanjing, People's Republic of China, 210098.
| | - Guoxiang You
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, People's Republic of China, 210098
| | - Jinbao Yin
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, People's Republic of China, 210098
| | - Mairan Zhang
- College of Agricultural Science and Engineering, Hohai University, Nanjing, People's Republic of China, 210098
| | - Dengyun Peng
- College of Agricultural Science and Engineering, Hohai University, Nanjing, People's Republic of China, 210098
| | - Junzeng Xu
- College of Agricultural Science and Engineering, Hohai University, Nanjing, People's Republic of China, 210098; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China
| | - Shihong Yang
- College of Agricultural Science and Engineering, Hohai University, Nanjing, People's Republic of China, 210098; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China.
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, People's Republic of China, 210098
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Mohammed SJ, Al-Musawi AT, Al-Fraji AS, Kareem HS. Comparison of three culture media in assessing the sensitivity of antibiotics to common foodborne microorganisms. J Med Life 2022; 15:645-649. [PMID: 35815083 PMCID: PMC9262258 DOI: 10.25122/jml-2021-0404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/16/2022] [Indexed: 11/19/2022] Open
Abstract
This study aimed to determine the antibiotic susceptibility of seven antibiotics, (Amoxicillin (AX), Ampicillin (AM), Chloramphenicol (C), Ciprofloxacin (CIP), Doxycycline (DO), Gentamicin (CN) and Neomycin (N)) on some common microorganisms that cause food poisoning. Furthermore, we aimed to compare three types of culture media in assessing antibiotics susceptibility. A sensitivity test was carried out using six bacterial isolates: Micrococcus spp., Staphylococcus aureus, Escherichia coli, Salmonella spp., Proteus mirabilis, Pseudomonas aeruginosa. These bacterial isolates were identified at the Food Microbiology Division, Public Health Laboratory using three culture media: Mueller Hinton Agar (MHA), Antibiotic Assay Medium A (AAM), and nutrient agar (NA). The results showed that all of these media are suitable to test antibiotic sensitivity. Bacterial sensitivity and resistance between these media (P≤0.01) were recorded, with significant differences found at the tested probability level.
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Affiliation(s)
- Sudad Jasim Mohammed
- Market Research and Consumer Protection Center, University of Baghdad, Baghdad, Iraq,Corresponding Author: Sudad Jasim Mohammed, Market Research and Consumer Protection Center, University of Baghdad, Baghdad, Iraq. E-mail:
| | - Adil Turki Al-Musawi
- Market Research and Consumer Protection Center, University of Baghdad, Baghdad, Iraq
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5
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Mudge MC, Nunn BL, Firth E, Ewert M, Hales K, Fondrie WE, Noble WS, Toner J, Light B, Junge KA. Subzero, saline incubations of
Colwellia psychrerythraea
reveal strategies and biomarkers for sustained life in extreme icy environments. Environ Microbiol 2021; 23:3840-3866. [DOI: 10.1111/1462-2920.15485] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/22/2021] [Indexed: 11/26/2022]
Affiliation(s)
- Miranda C. Mudge
- Department of Genome Sciences University of Washington Seattle WA USA
- Department of Molecular and Cellular Biology University of Washington Seattle WA USA
| | - Brook L. Nunn
- Department of Genome Sciences University of Washington Seattle WA USA
- Astrobiology Program University of Washington Seattle WA USA
| | - Erin Firth
- Applied Physics Lab, Polar Science Center University of Washington Seattle WA USA
| | - Marcela Ewert
- Applied Physics Lab, Polar Science Center University of Washington Seattle WA USA
| | - Kianna Hales
- Department of Genome Sciences University of Washington Seattle WA USA
| | | | - William S. Noble
- Department of Genome Sciences University of Washington Seattle WA USA
- Paul G. Allen School of Computer Science and Engineering University of Washington Seattle WA USA
| | - Jonathan Toner
- Department of Earth and Space Sciences University of Washington Seattle WA USA
| | - Bonnie Light
- Applied Physics Lab, Polar Science Center University of Washington Seattle WA USA
| | - Karen A. Junge
- Applied Physics Lab, Polar Science Center University of Washington Seattle WA USA
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Azpiazu-Muniozguren M, Martinez-Ballesteros I, Gamboa J, Seoane S, Alonso R, Laorden L, Garaizar J, Bikandi J. Altererythrobacter muriae sp. nov., isolated from hypersaline Añana Salt Valley spring water, a continental thalassohaline-type solar saltern. Int J Syst Evol Microbiol 2021; 71. [PMID: 33666546 DOI: 10.1099/ijsem.0.004734] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel salt-tolerant alpha-proteobacterium, designated SALINAS58T, was isolated from Santa Engracia hypersaline spring water in the Añana Salt Valley, Álava, Spain. The isolate was Gram-negative, aerobic, non-motile, catalase-positive, oxidase-negative, rod-shaped and formed orange colonies on marine agar. Optimal growth was observed at pH 6.0-6.5, at 30 °C and in the presence of 1% (w/v) NaCl. The main cellular fatty acids (>20%) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). The major respiratory quinone was ubiquinone Q-10 and the major polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidilglycerol, four unidentified glycolipids and one unidentified phospholipid. Strain SALINAS58T had the highest 16S rRNA gene sequence similarity to Altererythrobacter marensis MSW-14T (96.6%), Altererythrobacter aquaemixtae JSSK-8T (96.5%) and Pontixanthobacter luteolus SW-109T (96.5%) followed by Altererythrobacter atlanticus 26DY36T (96.4%). Results of the phylogenetic analysis, based on 16S rRNA gene sequences, and phylogenetic approaches based on whole genome nucleotide differences, showed that strain SALINAS58T could be distinguished from recognized species of the genus Altererythrobacter. The genomic DNA G+C content was 61.4 mol%. Digital DNA-DNA hybridization, average nucleotide identity and average aminoacid identity values between the genome of strain SALINAS58T and A. marensis MSW-14T were 18.4, 73.1 and 68.1%, respectively. Based on data from this polyphasic characterization, strain SALINAS58T (=CECT 30029T=LMG 31726T) is considered to be classified as representing a novel species in the genus Altererythrobacter, for which the name Altererythrobacter muriae sp. nov. is proposed.
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Affiliation(s)
- Maia Azpiazu-Muniozguren
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
| | - Ilargi Martinez-Ballesteros
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
| | | | - Sergio Seoane
- Plant Biology and Ecology Department, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Rodrigo Alonso
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
| | - Lorena Laorden
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
| | - Javier Garaizar
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
| | - Joseba Bikandi
- MikroIker Research Group. Immunology, Microbiology and Parasitology Department, Farmacy Faculty, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Álava, Spain
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7
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Yu X, Wei H, Liu X, Liu D, Fan A, Su H. Enhanced resistance of Trichoderma harzianum LZDX-32-08 to hygromycin B induced by sea salt. Biotechnol Lett 2020; 43:213-222. [PMID: 32851464 DOI: 10.1007/s10529-020-02994-y] [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: 04/30/2020] [Accepted: 08/18/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To determine the effect of sea salt on the resistance of Trichoderma harzianum LZDX-32-08 to hygromycin B and speculate the possible mechanisms involved via transcriptome analysis. RESULTS Sea salt addition in media to simulate marine environment significantly increased the tolerance of marine-derived fungus Trichoderma harzianum LZDX-32-08 to hygromycin B from 40 to 500 μg/ml. Meanwhile, sea salt addition also elicited the hygromycin B resistance of 5 other marine or terrestrial fungi. Transcriptomic analyses of T. harzianum cultivated on PDA, PDA supplemented with sea salt and PDA with both sea salt and hygromycin B revealed that genes coding for P-type ATPases, multidrug resistance related transporters and acetyltransferases were up-regulated, while genes coding for Ca2+/H+ antiporter and 1,3-glucosidase were down-regulated, indicating probable increased efflux and inactivation of hygromycin B as well as enhanced biofilm formation, which could jointly contribute to the drug resistance. CONCLUSIONS Marine environment or high ion concentration in the environment could be an importance inducer for antifungal resistance. Possible mechanisms and related key genes were proposed for understanding the molecular basis and overcoming this resistance.
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Affiliation(s)
- Xijia Yu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, North Third Ring Road 15, Chaoyang District, Beijing, 100029, People's Republic of China
| | - Huiling Wei
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, North Third Ring Road 15, Chaoyang District, Beijing, 100029, People's Republic of China
| | - Xianrui Liu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, North Third Ring Road 15, Chaoyang District, Beijing, 100029, People's Republic of China
| | - Dong Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, 100191, People's Republic of China
| | - Aili Fan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, North Third Ring Road 15, Chaoyang District, Beijing, 100029, People's Republic of China.
| | - Haijia Su
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, North Third Ring Road 15, Chaoyang District, Beijing, 100029, People's Republic of China
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Pal S, Sar A, Dam B. Moderate halophilic bacteria, but not extreme halophilic archaea can alleviate the toxicity of short-alkyl side chain imidazolium-based ionic liquids. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 184:109634. [PMID: 31520950 DOI: 10.1016/j.ecoenv.2019.109634] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/26/2019] [Accepted: 09/01/2019] [Indexed: 06/10/2023]
Abstract
Imidazolium-based ionic liquids (IL) with short-alkyl side chain such as 1-ethyl-3-methyl-imidazolium chloride ([Emim]Cl) and 1-butyl-3-methyl-imidazolium chloride ([Bmim]Cl) has immense application potential including in lignocellulosic bioenergy production. But they are toxic to most microorganisms, and those isolated from different environments as IL-tolerant have salt tolerance capabilities. This study evaluates the relationship between salt and [Emim]Cl tolerance of microorganisms using different salinity sediments (2-19%) and brines (35%) of India's largest inland hypersaline lake, Sambhar in Rajasthan as the model system. While samples with 2% and 35% salinities do not yield any [Emim]Cl (100 mM) tolerant colonies, others have 6-50% colonies tolerant to the IL. Similar trend was observed with 50 mM [Bmim]Cl. Moderate halophilic isolates of genera Halomonas and Bacillus (growth in 0.7-3.0 M NaCl) isolated from the sediments could grow in as high as 375 mM [Emim]Cl, or 125 mM [Bmim]Cl facilitated by higher synthesis, and uptake of organic osmolytes; and up to 1.7-fold increased activity of active efflux pumps. [Bmim]Cl was more toxic than [Emim]Cl in all performed experiments. [Emim]Cl-adapted cells could trounce IL-induced stress. Interestingly, enrichment with 100 mM [Emim]Cl resulted in increase of IL-tolerant colonies in all sediments including the one with 2% salinity. However, the salt saturated brines (35%) do not yield any such colony even after repeated incubations. Extreme halophilic archaea, Natronomonas (growth in 3.0-4.0 M NaCl) isolated from such brines, were exceedingly sensitive to even 5 mM [Emim]Cl, or 1 mM [Bmim]Cl. Two additional extremophilic archaea, namely Haloferax and Haladaptatus were also sensitive to the tested ILs. Archaeal sensitivity is possibly due to the competitive interaction of [Emim]+ with their acidic proteome (15.4-17.5% aspartic and glutamic acids, against 10.7-12.9% in bacteria) that they maintain to stabilize the high amount of K+ ion accumulated by salt-in strategy. Thus, general salt adaptation strategies of moderate halophilic bacteria help them to restrain toxicity of these ILs, but extremophilic archaea are highly sensitive and demands meticulous use of these solvents to prevent environmental contamination.
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Affiliation(s)
- Srikanta Pal
- Microbiology Laboratory, Department of Botany (DST-FIST & UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India
| | - Abhijit Sar
- Microbiology Laboratory, Department of Botany (DST-FIST & UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India
| | - Bomba Dam
- Microbiology Laboratory, Department of Botany (DST-FIST & UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India.
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9
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Zhang DF, Ye JZ, Dai HH, Lin XM, Li H, Peng XX. Identification of ethanol tolerant outer membrane proteome reveals OmpC-dependent mechanism in a manner of EnvZ/OmpR regulation in Escherichia coli. J Proteomics 2018. [PMID: 29518576 DOI: 10.1016/j.jprot.2018.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ethanol is an efficient disinfectant, but long-term and wide usage of ethanol leads to microbial tolerance. Bacteria with the tolerance are widely identified. However, mechanisms of the tolerance are not elucidated. To explore the mechanisms of outer membrane (OM) proteins underlying ethanol tolerance in bacteria, functional proteomic methodologies were utilized to characterize OM proteins of E. coli suddenly exposed to 3.125% ethanol. Of eleven proteins altered significantly, seven were OM proteins, in which LamB, FadL and OmpC were up-regulated, and OmpT, OmpF, Tsx and OmpA were down-regulated. The alterations were validated using Western blot. Then, functional characterization of the altered abundance of OM proteins was investigated in gene-deleted and gene-complemented mutants cultured in 1.56-6.25% ethanol. Higher inhibiting rate was detected in ΔompC than ΔlamB and ΔompA, but no difference was found between Δtsx, ΔompF, ΔfadL or ΔompT and control. Furthermore, EnvZ/OmpR two-component signal transduction system, which regulates OmpC and OmpF expression, was determined to participate in the tolerance. Finally, our results show that absence of envZ, ompR or ompC and ompA led to elevated and reduced intracellular ethanol, respectively. These findings indicate EnvZ-dependent phosphotransfer signaling pathway of the OmpR-mediated expression of OmpC plays a crucial role in ethanol tolerance. BIOLOGICAL SIGNIFICANCE Ethanol tolerance is an adaptation strategy of bacteria. In the present study, we used the proteomic approaches involving 2-DE and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) to determined outer membrane (OM) protein changes in E. coli K-12 after 2 h of 1/2 MIC of ethanol exposure. Under ethanol stress, seven differential OM proteins were found, which were validated by Western blot. Functions of these seven OM proteins were compared using their genetically modified strains. Furthermore, the role of EnvZ/OmpR two-component signal transduction system was identified in ethanol tolerance of E. coli. Finally, Loss of ompC, envZ or ompR increases intracellular ethanol, while absence of ompA reduces reversal effect. This is the first report of OM proteomics in E. coli exposed to ethanol. Our findings reveal an unknown OmpC-dependent mechanism of ethanol tolerance in a manner of EnvZ/OmpR regulation.
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Affiliation(s)
- Dan-Feng Zhang
- School of Biological Science and Biotechnology, Minnan Normal University, Zhangzhou 363000, People's Republic of China
| | - Jin-Zhou Ye
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Province Key Laboratory for Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China
| | - Hong-Hou Dai
- Clinical Laboratory, Affiliated Hospital of Jinggangshan University, 343000, People's Republic of China
| | - Xiang-Min Lin
- Agroecological Institute, Fujian Agricultural and Forestry University, Fuzhou 350002, People's Republic of China
| | - Hui Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Province Key Laboratory for Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China.
| | - Xuan-Xian Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, Guangdong Province Key Laboratory for Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China.
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10
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Establishment of a markerless gene deletion system in Chromohalobacter salexigens DSM 3043. Extremophiles 2017; 21:839-850. [DOI: 10.1007/s00792-017-0946-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/17/2017] [Indexed: 01/18/2023]
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11
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Harrison JP, Angel R, Cockell CS. Astrobiology as a framework for investigating antibiotic susceptibility: a study of Halomonas hydrothermalis. J R Soc Interface 2017; 14:20160942. [PMID: 28123098 PMCID: PMC5310740 DOI: 10.1098/rsif.2016.0942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/14/2016] [Indexed: 01/19/2023] Open
Abstract
Physical and chemical boundaries for microbial multiplication on Earth are strongly influenced by interactions between environmental extremes. However, little is known about how interactions between multiple stress parameters affect the sensitivity of microorganisms to antibiotics. Here, we assessed how 12 distinct permutations of salinity, availability of an essential nutrient (iron) and atmospheric composition (aerobic or microaerobic) affect the susceptibility of a polyextremotolerant bacterium, Halomonas hydrothermalis, to ampicillin, kanamycin and ofloxacin. While salinity had a significant impact on sensitivity to all three antibiotics (as shown by turbidimetric analyses), the nature of this impact was modified by iron availability and the ambient gas composition, with differing effects observed for each compound. These two parameters were found to be of particular importance when considered in combination and, in the case of ampicillin, had a stronger combined influence on antibiotic tolerance than salinity. Our data show how investigating microbial responses to multiple extremes, which are more representative of natural habitats than single extremes, can improve our understanding of the effects of antimicrobial compounds and suggest how studies of habitability, motivated by the desire to map the limits of life, can be used to systematically assess the effectiveness of antibiotics.
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Affiliation(s)
- Jesse P Harrison
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, UK
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network 'Chemistry Meets Microbiology', University of Vienna, Vienna 1090, Austria
| | - Roey Angel
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network 'Chemistry Meets Microbiology', University of Vienna, Vienna 1090, Austria
| | - Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, UK
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12
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Overexpression of the quorum-sensing regulator sdiA and soxS is involved in low-level multidrug resistance induced in Escherichia coli AG100 by haloperidol, diazepam and NaCl. Int J Antimicrob Agents 2011; 39:91-3. [PMID: 21982145 DOI: 10.1016/j.ijantimicag.2011.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/24/2011] [Accepted: 08/25/2011] [Indexed: 01/06/2023]
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13
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Kataoka N, Tajima T, Kato J, Rachadech W, Vangnai AS. Development of butanol-tolerant Bacillus subtilis strain GRSW2-B1 as a potential bioproduction host. AMB Express 2011; 1:10. [PMID: 21906347 PMCID: PMC3222312 DOI: 10.1186/2191-0855-1-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 05/30/2011] [Indexed: 11/23/2022] Open
Abstract
As alternative microbial hosts for butanol production with organic-solvent tolerant trait are in high demands, a butanol-tolerant bacterium, Bacillus subtilis GRSW2-B1, was thus isolated. Its tolerance covered a range of organic solvents at high concentration (5%v/v), with remarkable tolerance in particular to butanol and alcohol groups. It was susceptible for butanol acclimatization, which resulted in significant tolerance improvement. It has versatility for application in a variety of fermentation process because it has superior tolerance when cells were exposed to butanol either as high-density, late-exponential grown cells (up to 5%v/v) or under growing conditions (up to 2.25%v/v). Genetic transformation procedure was optimized, yielding the highest efficiency at 5.17 × 103 colony forming unit (μg DNA)-1. Gene expression could be effectively driven by several promoters with different levels, where as the highest expression was observed with a xylose promoter. The constructed vector was stably maintained in the transformants, in the presence or absence of butanol stress. Adverse effect of efflux-mediated tetracycline resistance determinant (TetL) to bacterial organic-solvent tolerance property was unexpectedly observed and thus discussed. Overall results indicate that B. subtilis GRSW2-B1 has potential to be engineered and further established as a genetic host for bioproduction of butanol.
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14
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Godoy P, Molina‐Henares AJ, De La Torre J, Duque E, Ramos JL. Characterization of the RND family of multidrug efflux pumps: in silico to in vivo confirmation of four functionally distinct subgroups. Microb Biotechnol 2010; 3:691-700. [PMID: 21255364 PMCID: PMC3815342 DOI: 10.1111/j.1751-7915.2010.00189.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 05/04/2010] [Indexed: 11/12/2022] Open
Abstract
We have developed a generalized profile that identifies members of the root-nodulation-cell-division (RND) family of efflux pumps and classifies them into four functional subfamilies. According to Z-score values, efflux pumps can be grouped by their metabolic function, thus making it possible to distinguish pumps involved in antibiotic resistance (group 1) from those involved in metal resistance (group 3). In silico data regarding efflux pumps in group 1 were validated after identification of RND efflux pumps in a number of environmental microbes that were isolated as resistant to ethidium bromide. Analysis of the Pseudomonas putida KT2440 genome identified efflux pumps in all groups. A collection of mutants in efflux pumps and a screening platform consisting of 50 drugs were created to assign a function to the efflux pumps. We validated in silico data regarding efflux pumps in groups 1 and 3 using 9 different mutants. Four mutants belonging to group 2 were found to be more sensitive than the wild-type to oxidative stress-inducing agents such as bipyridyl and methyl viologen. The two remaining mutants belonging to group 4 were found to be more sensitive than the parental to tetracycline and one of them was particularly sensitive to rubidium and chromate. By effectively combining in vivo data with generalized profiles and gene annotation data, this approach allowed the assignment, according to metabolic function, of both known and uncharacterized RND efflux pumps into subgroups, thereby providing important new insight into the functions of proteins within this family.
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Affiliation(s)
| | | | | | | | - Juan L. Ramos
- Consejo Superior de Investigaciones Científicas, Department of Environmental Protection, E‐18008 Granada, Spain
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15
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Prakash D, Pandey J, Tiwary BN, Jain RK. Physiological adaptations and tolerance towards higher concentration of selenite (Se+4) in Enterobacter sp. AR-4, Bacillus sp. AR-6 and Delftia tsuruhatensis AR-7. Extremophiles 2010; 14:261-72. [DOI: 10.1007/s00792-010-0305-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 02/22/2010] [Indexed: 11/29/2022]
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16
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Investigation of saturated and aromatic hydrocarbon resistance mechanisms in Pseudomonas aeruginosa IBBML1. Open Life Sci 2009. [DOI: 10.2478/s11535-009-0050-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractPseudomonas aeruginosa IBBML1, isolated from Poeni petroleum sludge, was able to tolerate and degrade both saturated (n-hexane, n-heptane, n-hexadecane, cyclohexane) and aromatic (benzene, ethylbenzene, propylbenzene, xylene isomers, styrene) hydrocarbons. Molecular studies have revealed that the high hydrocarbon resistance of Pseudomonas aeruginosa IBBML1 could be due to the action of members of the HAE1 (hydrophobe/amphiphile efflux 1) family of transporters. It is further possible that additional mechanisms may account for the tolerance of Pseudomonas aeruginosa IBBML1 to hydrocarbons, and a combination of short-term and long-term mechanisms may act together in the adaptation of Pseudomonas aeruginosa IBBML1 cells to saturated and aromatic hydrocarbons. β-galactosidase activity measurements revealed that there was significant induction of the lacZ gene in Pseudomonas aeruginosa IBBML1 cells grown in the presence of either 5% and 10% (v/v) saturated or aromatic hydrocarbons, compared with control (cells incubated without hydrocarbons). Rhodamine 6G accumulation in Pseudomonas aeruginosa IBBML1 cells grown in the presence of 5% and 10% (v/v) saturated hydrocarbons was higher than rhodamine 6G accumulation in cells grown in the presence of 5% and 10% (v/v) aromatic hydrocarbons. The study of cellular and molecular modifications to Pseudomonas aeruginosa IBBML1 induced by 5% and 10% (v/v) saturated and aromatic hydrocarbons revealed a complex response of bacterial cells to the presence of different hydrophobic substrates in the culture medium.
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Halophilic beta-lactamase as a new solubility- and folding-enhancing tag protein: production of native human interleukin 1alpha and human neutrophil alpha-defensin. Appl Microbiol Biotechnol 2009; 86:649-58. [PMID: 19902204 DOI: 10.1007/s00253-009-2325-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 10/09/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
The amino acid composition of halophilic enzymes is characterized by an abundant content of acidic amino acid, which confers to the halophilic enzymes extensive negative charges at neutral pH and high aqueous solubility. This negative charge prevents protein aggregation when denatured and thereby leads to highly efficient protein refolding. Beta-lactamase from periplasmic space of moderate halophile (BLA), a typical halophilic enzyme, can be readily expressed as a native, active form in Escherichia coli cytoplasm. Similar to other halophilic enzymes, BLA is soluble upon denaturation by heat or urea treatments and, hence, can be efficiently refolded. Such high solubility and refolding efficiency make BLA a potential fusion partner for expression of aggregation-prone heterologous proteins to be expressed in E. coli. Here, we succeeded in the soluble expression of several "difficult-to-express" proteins as a BLA fusion protein and verified biological activities of human interleukin 1alpha and human neutrophil alpha-defensin, HNP-1.
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18
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Abstract
Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario K1A OK9, Canada
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA
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Lazaroaie MM. Modifications Induced by Organic Solvents to Aeromonas hydrophila IB B ct4. JOURNAL OF THE KOREAN CHEMICAL SOCIETY-DAEHAN HWAHAK HOE JEE 2009. [DOI: 10.5012/jkcs.2009.53.3.325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Fernández-Delgado M, Contreras M, García-Amado MA, Gueneau P, Suárez P. Occurrence of Proteus mirabilis associated with two species of venezuelan oysters. Rev Inst Med Trop Sao Paulo 2008; 49:355-9. [PMID: 18157401 DOI: 10.1590/s0036-46652007000600004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 06/11/2007] [Indexed: 11/22/2022] Open
Abstract
The fecal contamination of raw seafood by indicators and opportunistic pathogenic microorganisms represents a public health concern. The objective of this study was to investigate the presence of enteric bacteria colonizing oysters collected from a Venezuelan touristic area. Oyster samples were collected at the northwestern coast of Venezuela and local salinity, pH, temperature, and dissolved oxygen of seawater were recorded. Total and fecal coliforms were measured for the assessment of the microbiological quality of water and oysters, using the Multiple Tube Fermentation technique. Analyses were made using cultures and 16S rRNA gene sequencing. Diverse enrichment and selective culture methods were used to isolate enteric bacteria. We obtained pure cultures of Gram-negative straight rods with fimbriae from Isognomon alatus and Crassostrea rhizophorae. Our results show that P. mirabilis was predominant under our culture conditions. We confirmed the identity of the cultures by biochemical tests, 16S rRNA gene sequencing, and data analysis. Other enterobacteria such as Escherichia coli, Morganella morganii and Klebsiella pneumoniae were also isolated from seawater and oysters. The presence of pathogenic bacteria in oysters could have serious epidemiological implications and a potential human health risk associated with consumption of raw seafood.
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Mimura H, Sato R, Furuyama Y, Taniike A, Yagi M, Yoshida K, Kitamura A. Adsorption of tributyltin by tributyltin resistant marine Pseudoalteromonas sp. cells. MARINE POLLUTION BULLETIN 2008; 57:877-882. [PMID: 18468645 DOI: 10.1016/j.marpolbul.2008.03.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 02/29/2008] [Accepted: 03/15/2008] [Indexed: 05/26/2023]
Abstract
The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 microM in the absence of Cl(-) in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10(7.5) TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm.
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Affiliation(s)
- Haruo Mimura
- Graduate School of Maritime Sciences, Kobe University, 5-1-1, Fukae, Higashinada, Kobe 658-0022, Japan.
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Segura A, Hurtado A, Rivera B, Lazaroaie M. Isolation of new toluene-tolerant marine strains of bacteria and characterization of their solvent-tolerance properties. J Appl Microbiol 2008; 104:1408-16. [DOI: 10.1111/j.1365-2672.2007.03666.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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DeVito JA. Recombineering with tolC as a selectable/counter-selectable marker: remodeling the rRNA operons of Escherichia coli. Nucleic Acids Res 2007; 36:e4. [PMID: 18084036 PMCID: PMC2248734 DOI: 10.1093/nar/gkm1084] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This work describes the novel use of tolC as a selectable/counter-selectable marker for the facile modification of DNA in Escherichia coli. Expression of TolC (an outer membrane protein) confers relative resistance to toxic small molecules, while its absence renders the cell tolerant to colicin E1. These features, coupled with the lambdaredgam recombination system, allow for selection of tolC insertions/deletions anywhere on the E. coli chromosome or on plasmid DNA. This methodology obviates the need for minimal growth media, specialized wash protocols and the lengthy incubation times required by other published recombineering methods. As a rigorous test of the TolC selection system, six out of seven 23S rRNA genes were consecutively and seamlessly removed from the E. coli chromosome without affecting expression of neighboring genes within the complex rrn operons. The resulting plasmid-free strain retains one 23S rRNA gene (rrlC) in its natural location on the chromosome and is the first mutant of its kind. These new rRNA mutants will be useful in the study of rRNA gene regulation and ribosome function. Given its high efficiency, low background and facility in rich media, tolC selection is a broadly applicable method for the modification of DNA by recombineering.
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Affiliation(s)
- Joseph A DeVito
- Discovery Biology, Rib-X Pharmaceuticals Inc., New Haven, CT 06511, USA.
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Li X, Eda S, Nakae T. Organic solvent-selective domain of the resistance-nodulation-division-type xenobiotic-antibiotic transporters of Pseudomonas aeruginosa. Microbiol Immunol 2006; 50:53-6. [PMID: 16428873 DOI: 10.1111/j.1348-0421.2006.tb03770.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydrophobic substrate-selective domain of the resistance-nodulation-division-type xenobiotic transporter of Pseudomonas aeruginosa was assigned based on the different organic-solvent selectivities of MexB and MexY. The MexB-MexY hybrid protein consisting of two large periplasmic domains of MexB and the transmembrane domains of MexY showed MexB-type organic solvent selectivity. The results imply that the resistance-nodulation-division-type xenobiotic transporters recognize hydrophobic substrates such as organic solvents by their periplasmic domains and expel them to the external milieu. This is an elegant way to protect the cytoplasmic membrane from membrane-deteriorating agents.
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Affiliation(s)
- Xiaohong Li
- Institute of Medical Science, Tokai University, Isehara, Kanagawa 259-1193, Japan
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Ghozlan H, Deif H, Kandil RA, Sabry S. Biodiversity of moderately halophilic bacteria in hypersaline habitats in Egypt. J GEN APPL MICROBIOL 2006; 52:63-72. [PMID: 16778349 DOI: 10.2323/jgam.52.63] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Screening bacteria from different saline environments in Alexandria. Egypt, lead to the isolation of 76 Gram-negative and 14 Gram-positive moderately halophilic bacteria. The isolates were characterized taxonomically for a total of 155 features. These results were analyzed by numerical techniques using simple matching coefficient (SSM) and the clustering was achieved by the unweighed pair-group method of association (UPGMA). At 75% similarity level the Gram-negative bacteria were clustered in 7 phena in addition to one single isolate, whereas 4 phena represented the Gram-positive. Based on phenotypic characteristics, it is suggested that the Gram-negative bacteria belong to the genera Pseudoalteromonas, Flavobacterium, Chromohalobacter, Halomonas and Salegentibacter, in addition to the non-identified single isolate. The Gram-positive bacteria are proposed to belong to the genera Halobacillus, Salinicoccus, Staphylococcus and Tetragenococcus. This study provides the first publication on the biodiversity of moderately halophilic bacteria in saline environments in Alexandria, Egypt.
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Affiliation(s)
- Hanan Ghozlan
- Department of Botany, Faculty of Science, University of Alexandria, Egypt.
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Stepanauskas R, Glenn TC, Jagoe CH, Tuckfield RC, Lindell AH, McArthur JV. Elevated microbial tolerance to metals and antibiotics in metal-contaminated industrial environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:3671-8. [PMID: 15952371 DOI: 10.1021/es048468f] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To test the hypothesis that industrial metal contaminants select for microorganisms tolerant to unrelated agents, such as antibiotics, we analyzed metal and antibiotic tolerance patterns in microbial communities in the intake and discharge of ash settling basins (ASBs) of three coal-fired power plants. High-throughput flow-cytometric analyses using cell viability probes were employed to determine tolerances of entire bacterioplankton communities, avoiding bias toward culturable versus nonculturable bacteria. We found that bacterioplankton collected in ASB discharges were significantly more tolerant to metal and antibiotic exposures than bacterioplankton collected in ASB intakes. Optical properties of microorganisms collected in ASB discharges indicated no defensive physiological adaptations such as formation of resting stages or excessive production of exopolymers. Thus, it is likely that the elevated frequency of metal and antibiotic tolerances in bacterioplankton in ASB discharges were caused by shifts in microbial community composition, resulting from the selective pressure imposed by elevated metal concentrations or organic toxicants present in ASBs.
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Affiliation(s)
- Ramunas Stepanauskas
- Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, South Carolina 29802, USA.
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