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Trognon J, Rima M, Lajoie B, Roques C, El Garah F. NaCl-induced modulation of species distribution in a mixed P. aeruginosa / S. aureus / B.cepacia biofilm. Biofilm 2023; 6:100153. [PMID: 37711514 PMCID: PMC10497989 DOI: 10.1016/j.bioflm.2023.100153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023] Open
Abstract
Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia are notorious pathogens known for their ability to form resilient biofilms, particularly within the lung environment of cystic fibrosis (CF) patients. The heightened concentration of NaCl, prevalent in the airway liquid of CF patients' lungs, has been identified as a factor that promotes the growth of osmotolerant bacteria like S. aureus and dampens host antibacterial defenses, thereby fostering favorable conditions for infections. In this study, we aimed to investigate how increased NaCl concentrations impact the development of multi-species biofilms in vitro, using both laboratory strains and clinical isolates of P. aeruginosa, S. aureus, and B. cepacia co-cultures. Employing a low-nutrient culture medium that fosters biofilm growth of the selected species, we quantified biofilm formation through a combination of adherent CFU counts, qPCR analysis, and confocal microscopy observations. Our findings reaffirmed the challenges faced by S. aureus in establishing growth within 1:1 mixed biofilms with P. aeruginosa when cultivated in a minimal medium. Intriguingly, at an elevated NaCl concentration of 145 mM, a symbiotic relationship emerged between S. aureus and P. aeruginosa, enabling their co-existence. Notably, this hyperosmotic environment also exerted an influence on the interplay of these two bacteria with B. cepacia. We demonstrated that elevated NaCl concentrations play a pivotal role in orchestrating the distribution of these three species within the biofilm matrix. Furthermore, our study unveiled the beneficial impact of NaCl on the biofilm growth of clinically relevant mucoid P. aeruginosa strains, as well as two strains of methicillin-sensitive and methicillin-resistant S. aureus. This underscores the crucial role of the microenvironment during the colonization and infection processes. The results suggest that hyperosmotic conditions could hold the key to unlocking a deeper understanding of the genesis and behavior of CF multi-species biofilms.
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Affiliation(s)
- Jeanne Trognon
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Maya Rima
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Barbora Lajoie
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Christine Roques
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service de Bactériologie Hygiène, Toulouse, France
| | - Fatima El Garah
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
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Lin J, Xie J, Luo L, Gänzle M. Characterization of GshAB of Tetragenococcus halophilus: a two-domain glutathione synthetase. Appl Microbiol Biotechnol 2023; 107:2997-3008. [PMID: 36995384 DOI: 10.1007/s00253-023-12497-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/31/2023]
Abstract
The γ-glutamyl tripeptide glutathione (γ-Glu-Cys-Gly) is a low molecular thiol that acts as antioxidant in response to oxidative stress in eukaryotes and prokaryotes. γ-Glutamyl dipeptides including γ-Glu-Cys, γ-Glu-Glu, and γ-Glu-Gly also have kokumi activity. Glutathione is synthesized by first ligating Glu with Cys by γ-glutamylcysteine ligase (Gcl/GshA), and then the resulting dipeptide γ-glutamylcysteine is ligated with Gly by glutathione synthetase (Gs/GshB). GshAB/GshF enzymes that contain both Gcl and Gs domains are capable of catalyzing both reactions. The current study aimed to characterize GshAB from Tetragenococcus halophilus after heterologous expression in Escherichia coli. The optimal conditions for GshAB from T. halophilus were pH 8.0 and 25 °C. The substrate specificity of the Gcl reaction of GshAB was also determined. GshAB has a high affinity to Cys. γ-Glu-Cys was the only dipeptide generated when Glu, Cys, Gly, and other amino acids were present in the reaction system. This specificity differentiates GshAB from T. halophilus from Gcl of heterofermentative lactobacilli and GshAB of Streptococcus agalactiae, which also use amino acids other than Cys as glutamyl-acceptor. Quantification of gshAB in cDNA libraries from T. halophilus revealed that gshAB was overexpressed in response to oxidative stress but not in response to acid, osmotic, or cold stress. In conclusion, GshAB in T. halophilus served as part of the oxidative stress response but this study did not provide any evidence for a contribution to the resistance to other stressors.Key points Glutathione synthesis in Tetragenococcus halophilus is carried out by the two-domain enzyme GshAB. GshAB is inhibited by glutathione and is highly specific for Cys as acceptor. T. halophilus synthesizes glutathione in response to oxidative stress.
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Affiliation(s)
- Jieting Lin
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, T6G 2P5, Canada
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, China
- Present address: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Jin Xie
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, T6G 2P5, Canada
| | - Lixin Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, China
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, T6G 2P5, Canada.
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Ndubuisi IA, Amadi CO, Nwagu TN, Murata Y, Ogbonna JC. Non-conventional yeast strains: Unexploited resources for effective commercialization of second generation bioethanol. Biotechnol Adv 2023; 63:108100. [PMID: 36669745 DOI: 10.1016/j.biotechadv.2023.108100] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023]
Abstract
The conventional yeast (Saccharomyces cerevisiae) is the most studied yeast and has been used in many important industrial productions, especially in bioethanol production from first generation feedstock (sugar and starchy biomass). However, for reduced cost and to avoid competition with food, second generation bioethanol, which is produced from lignocellulosic feedstock, is now being investigated. Production of second generation bioethanol involves pre-treatment and hydrolysis of lignocellulosic biomass to sugar monomers containing, amongst others, d-glucose and D-xylose. Intrinsically, S. cerevisiae strains lack the ability to ferment pentose sugars and genetic engineering of S. cerevisiae to inculcate the ability to ferment pentose sugars is ongoing to develop recombinant strains with the required stability and robustness for commercial second generation bioethanol production. Furthermore, pre-treatment of these lignocellulosic wastes leads to the release of inhibitory compounds which adversely affect the growth and fermentation by S. cerevisae. S. cerevisiae also lacks the ability to grow at high temperatures which favour Simultaneous Saccharification and Fermentation of substrates to bioethanol. There is, therefore, a need for robust yeast species which can co-ferment hexose and pentose sugars and can tolerate high temperatures and the inhibitory substances produced during pre-treatment and hydrolysis of lignocellulosic materials. Non-conventional yeast strains are potential solutions to these problems due to their abilities to ferment both hexose and pentose sugars, and tolerate high temperature and stress conditions encountered during ethanol production from lignocellulosic hydrolysate. This review highlights the limitations of the conventional yeast species and the potentials of non-conventional yeast strains in commercialization of second generation bioethanol.
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Affiliation(s)
| | - Chioma O Amadi
- Department of Microbiology, University of Nigeria Nsukka, Nigeria
| | - Tochukwu N Nwagu
- Department of Microbiology, University of Nigeria Nsukka, Nigeria
| | - Y Murata
- Biological Resources and Post-Harvest Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - James C Ogbonna
- Department of Microbiology, University of Nigeria Nsukka, Nigeria.
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Lennen RM, Lim HG, Jensen K, Mohammed ET, Phaneuf PV, Noh MH, Malla S, Börner RA, Chekina K, Özdemir E, Bonde I, Koza A, Maury J, Pedersen LE, Schöning LY, Sonnenschein N, Palsson BO, Nielsen AT, Sommer MOA, Herrgård MJ, Feist AM. Laboratory evolution reveals general and specific tolerance mechanisms for commodity chemicals. Metab Eng 2023; 76:179-92. [PMID: 36738854 DOI: 10.1016/j.ymben.2023.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/06/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
Although strain tolerance to high product concentrations is a barrier to the economically viable biomanufacturing of industrial chemicals, chemical tolerance mechanisms are often unknown. To reveal tolerance mechanisms, an automated platform was utilized to evolve Escherichia coli to grow optimally in the presence of 11 industrial chemicals (1,2-propanediol, 2,3-butanediol, glutarate, adipate, putrescine, hexamethylenediamine, butanol, isobutyrate, coumarate, octanoate, hexanoate), reaching tolerance at concentrations 60%-400% higher than initial toxic levels. Sequencing genomes of 223 isolates from 89 populations, reverse engineering, and cross-compound tolerance profiling were employed to uncover tolerance mechanisms. We show that: 1) cells are tolerized via frequent mutation of membrane transporters or cell wall-associated proteins (e.g., ProV, KgtP, SapB, NagA, NagC, MreB), transcription and translation machineries (e.g., RpoA, RpoB, RpoC, RpsA, RpsG, NusA, Rho), stress signaling proteins (e.g., RelA, SspA, SpoT, YobF), and for certain chemicals, regulators and enzymes in metabolism (e.g., MetJ, NadR, GudD, PurT); 2) osmotic stress plays a significant role in tolerance when chemical concentrations exceed a general threshold and mutated genes frequently overlap with those enabling chemical tolerance in membrane transporters and cell wall-associated proteins; 3) tolerization to a specific chemical generally improves tolerance to structurally similar compounds whereas a tradeoff can occur on dissimilar chemicals, and 4) using pre-tolerized starting isolates can hugely enhance the subsequent production of chemicals when a production pathway is inserted in many, but not all, evolved tolerized host strains, underpinning the need for evolving multiple parallel populations. Taken as a whole, this study provides a comprehensive genotype-phenotype map based on identified mutations and growth phenotypes for 223 chemical tolerant isolates.
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Waditee-Sirisattha R, Kageyama H. Halotolerance, stress mechanisms, and circadian clock of salt-tolerant cyanobacteria. Appl Microbiol Biotechnol 2023; 107:1129-41. [PMID: 36700967 DOI: 10.1007/s00253-023-12390-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/27/2023]
Abstract
Cyanobacteria harbor a high level of physiological flexibility, which enables them to reside in virtually all available environmental niches, including extreme environments. In this review, we summarize the recent advancements in stress mechanisms of salt-tolerant (a.k.a. halotolerant) cyanobacteria. Omics approaches have been extensively employed in recent years to decipher mechanisms of halotolerance and to understand the relevance of halotolerance-associated gene regulatory networks. The vast knowledge from genome mining disclosed that halotolerant cyanobacteria possess extended gene families and/or clusters, encoding enzymes that synthesize unique osmoprotectants, including glycine betaine (GB), betaine derivatives, and mycosporine-like amino acids (MAAs). Comprehensive transcriptomic analyses were conducted using Halothece sp. PCC7418 (hereafter referred to as Halothece), a cyanobacterium that exhibits remarkable halotolerance. These studies revealed a specific transcriptional response when Halothece was subjected to salt stress, whereas salt and osmotic stresses were found to share a common transcriptomic response. Transcriptome and metabolite analyses of Halothece illustrated a complex dynamic relationship between the biosyntheses of osmoprotectants, as well as corresponding and ancillary pathways. Lastly, novel insights highlight the relationship between the molecular regulation of the circadian rhythm and salt stress tolerance. Since the circadian rhythm of gene expression was distorted under salt stress, halotolerant cyanobacteria may prioritize the adaptation to salt stress by attenuation of circadian rhythmicity. KEY POINTS: • Recent advancements in the understanding of stress mechanisms in halotolerant cyanobacteria are described based on omics analyses. • Transcriptome and metabolite analyses of Halothece illustrated a complex dynamic relationship between the biosyntheses of osmoprotectants, as well as corresponding and ancillary pathways. • Since salt stress affects the molecular regulation among clock-related proteins, salt stress may attenuate circadian rhythmicity.
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Sánchez ML, Chimeno SV, Mercado LA, Ciklic IF. Hybridization and spore dissection of native wine yeasts for improvement of ethanol resistance and osmotolerance. World J Microbiol Biotechnol 2022; 38:225. [PMID: 36121519 DOI: 10.1007/s11274-022-03400-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/22/2022] [Indexed: 10/14/2022]
Abstract
Global warming has a significant impact on different viticultural parameters, including grape maturation. An increment of photosynthetic activity generates a rapid accumulation of sugars in the berry, followed by a dehydration process which leads to a higher concentration of soluble solids. This effect is exacerbated by current viticultural practices which favor the harvest of very mature grapes to obtain wines with sweet tannins. Considering the initial hyperosmotic stress conditions and the high ethanol concentration of the produced wine, fermentation of grape musts with high sugar content could be problematic for yeast starters. In the present study, we were able to obtain by classical hybridization and spore dissection methods one hybrid and one monosporic wine yeast strain with a combined ethanol and osmotolerant phenotype. The improved yeasts were tested in vinification trials with high sugar concentration and displayed excellent fermentation performance. Importantly, the obtained wines also showed good organoleptic properties during sensory analysis. Based on our results, we believed our improved hybrid and monosporic strains can be considered good alternatives to be used as yeast starters for fermentations with high sugar content.
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Affiliation(s)
- María Laura Sánchez
- Departamento de Ciencias Enológicas y Agroalimentarias, Facultad de Ciencias Agrarias UNCUYO, Almirante Brown 500, 5505, Luján de Cuyo, Mendoza, Argentina
| | - Selva Valeria Chimeno
- Estación Experimental Agropecuaria Mendoza, Instituto Nacional de Tecnología Agropecuaria (INTA), San Martín 3853, 5507, Luján de Cuyo, Mendoza, Argentina
| | - Laura Analía Mercado
- Estación Experimental Agropecuaria Mendoza, Instituto Nacional de Tecnología Agropecuaria (INTA), San Martín 3853, 5507, Luján de Cuyo, Mendoza, Argentina
| | - Iván Francisco Ciklic
- Estación Experimental Agropecuaria Mendoza, Instituto Nacional de Tecnología Agropecuaria (INTA), San Martín 3853, 5507, Luján de Cuyo, Mendoza, Argentina.
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Song N, Xia H, Yang Q, Zhang X, Yao L, Yang S, Chen X, Dai J. Differential analysis of ergosterol function in response to high salt and sugar stress in Zygosaccharomyces rouxii. FEMS Yeast Res 2022; 22:6657072. [PMID: 35932192 DOI: 10.1093/femsyr/foac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/15/2022] [Accepted: 08/03/2022] [Indexed: 11/14/2022] Open
Abstract
Zygosaccharomyces rouxii is an osmotolerant and halotolerant yeast that can participate in fermentation. To understand the mechanisms of salt and sugar tolerance, the transcription levels of Z. rouxii M 2013310 under 180 g/L NaCl stress and 600 g/L glucose stress were measured. The transcriptome analysis showed that 2227 differentially expressed genes (DEGs) were identified under 180 g/L NaCl stress, 1530 DEGs were identified under 600 g/L glucose stress, and 1278 DEGs were identified under both stress conditions. Then, KEGG enrichment analyses of these genes indicated that 53.3% of the upregulated genes were involved in the ergosterol synthesis pathway. Subsequently, quantitative PCR was used to verify the results, which showed that the genes of the ergosterol synthesis pathway were significantly upregulated under 180 g/L NaCl stress. Finally, further quantitative testing of ergosterol and spotting assays revealed that Z. rouxii M 2013310 increased the amount of ergosterol in response to high salt stress. These results highlighted the functional differences in ergosterol under sugar stress and salt stress, which contributes to our understanding of the tolerance mechanisms of salt and sugar in Z. rouxii.
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Affiliation(s)
- Na Song
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), College of Bioengineering, Hubei University of Technology, Wuhan 430068, P.R. China
| | - Huili Xia
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), College of Bioengineering, Hubei University of Technology, Wuhan 430068, P.R. China
| | - Qiao Yang
- ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| | - Xiaoling Zhang
- ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| | - Lan Yao
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), College of Bioengineering, Hubei University of Technology, Wuhan 430068, P.R. China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, China, 430062
| | - Xiong Chen
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), College of Bioengineering, Hubei University of Technology, Wuhan 430068, P.R. China
| | - Jun Dai
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), College of Bioengineering, Hubei University of Technology, Wuhan 430068, P.R. China.,ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, China, 430062S
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Sander KB, Chung D, Klingeman DM, Giannone RJ, Rodriguez M, Whitham J, Hettich RL, Davison BH, Westpheling J, Brown SD. Gene targets for engineering osmotolerance in Caldicellulosiruptor bescii. Biotechnol Biofuels 2020; 13:50. [PMID: 32190115 PMCID: PMC7071700 DOI: 10.1186/s13068-020-01690-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 02/27/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Caldicellulosiruptor bescii, a promising biocatalyst being developed for use in consolidated bioprocessing of lignocellulosic materials to ethanol, grows poorly and has reduced conversion at elevated medium osmolarities. Increasing tolerance to elevated fermentation osmolarities is desired to enable performance necessary of a consolidated bioprocessing (CBP) biocatalyst. RESULTS Two strains of C. bescii showing growth phenotypes in elevated osmolarity conditions were identified. The first strain, ORCB001, carried a deletion of the FapR fatty acid biosynthesis and malonyl-CoA metabolism repressor and had a severe growth defect when grown in high-osmolarity conditions-introduced as the addition of either ethanol, NaCl, glycerol, or glucose to growth media. The second strain, ORCB002, displayed a growth rate over three times higher than its genetic parent when grown in high-osmolarity medium. Unexpectedly, a genetic complement ORCB002 exhibited improved growth, failing to revert the observed phenotype, and suggesting that mutations other than the deleted transcription factor (the fruR/cra gene) are responsible for the growth phenotype observed in ORCB002. Genome resequencing identified several other genomic alterations (three deleted regions, three substitution mutations, one silent mutation, and one frameshift mutation), which may be responsible for the observed increase in osmolarity tolerance in the fruR/cra-deficient strain, including a substitution mutation in dnaK, a gene previously implicated in osmoresistance in bacteria. Differential expression analysis and transcription factor binding site inference indicates that FapR negatively regulates malonyl-CoA and fatty acid biosynthesis, as it does in many other bacteria. FruR/Cra regulates neighboring fructose metabolism genes, as well as other genes in global manner. CONCLUSIONS Two systems able to effect tolerance to elevated osmolarities in C. bescii are identified. The first is fatty acid biosynthesis. The other is likely the result of one or more unintended, secondary mutations present in another transcription factor deletion strain. Though the locus/loci and mechanism(s) responsible remain unknown, candidate mutations are identified, including a mutation in the dnaK chaperone coding sequence. These results illustrate both the promise of targeted regulatory manipulation for osmotolerance (in the case of fapR) and the challenges (in the case of fruR/cra).
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Affiliation(s)
- Kyle B. Sander
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Bredesen Center for Interdisciplinary Graduate Research and Education, University of Tennessee, Knoxville, TN USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN USA
- Present Address: Department of Bioengineering, University of California, Berkeley, Berkeley, CA USA
| | - Daehwan Chung
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Department of Genetics, University of Georgia, Athens, GA USA
- Present Address: National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Dawn M. Klingeman
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Richard J. Giannone
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Miguel Rodriguez
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Jason Whitham
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Present Address: Becton Dickinson Diagnostics, Sparks Glencoe, MD USA
| | - Robert L. Hettich
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Bredesen Center for Interdisciplinary Graduate Research and Education, University of Tennessee, Knoxville, TN USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Janet Westpheling
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Department of Genetics, University of Georgia, Athens, GA USA
| | - Steven D. Brown
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Bredesen Center for Interdisciplinary Graduate Research and Education, University of Tennessee, Knoxville, TN USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Present Address: LanzaTech, Skokie, IL USA
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Jiang Y, Li Y, Lu C, Tang Y, Jiang X, Gai Y. Isolation and characterization of Populus xyloglucan endotransglycosylase/hydrolase (XTH) involved in osmotic stress responses. Int J Biol Macromol 2019; 155:1277-1287. [PMID: 31730960 DOI: 10.1016/j.ijbiomac.2019.11.099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 01/22/2023]
Abstract
Xyloglucan endotransglycosylase/hydrolase (XTH) belongs to the GH16 subfamily of the glycoside hydrolases of carbohydrate active enzymes and plays an important role in the structure and function of plant cell walls. In this study, 11 members of the XTH gene family were cloned from Populus tomentosa. A bioinformatics analysis revealed that 11 PtoXTHs could be classified into three groups, where PtoXTH27 and PtoXTH34 were most likely to exhibit XTH activity. Biochemical analyses of purified PtoXTHs demonstrated that PtoXTH27 and PtoXTH34 had detectable xyloglucan endotransglucosylase (XET) activity, while the others did not exhibit XET or XEH activity. Moreover, enzymatic assays revealed that the optimum reaction temperature of both PtoXTH27 and PtoXTH34 was 37 °C, while their optimum pH values differed, such that PtoXTH27 was 6.0 and PtoXTH34 was 5.0. Enzyme kinetic parameters indicated that PtoXTH34 had higher affinity for the receptor substrate, XXXG, implying that PtoXTH34 and PtoXTH27 in plants have different substrate structure specificity. Finally, heterologous expression of XTH significantly increased intracellular total sugar content and osmotolerance of yeast cells, indicating that PtoXTH27 and PtoXTH34 are potentially involved in osmotic stress responses. These results clearly demonstrate the enzymatic characteristics and putative role of XTH in osmotic stress responses.
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Affiliation(s)
- Yan Jiang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China
| | - Yuhua Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China
| | - Chen Lu
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China
| | - Yanni Tang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China
| | - Xiangning Jiang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China; The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, National Engineering Laboratory for Tree Breeding, Beijing 100083, P.R. China
| | - Ying Gai
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, P.R. China; The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, National Engineering Laboratory for Tree Breeding, Beijing 100083, P.R. China.
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Byrne E, Kovacs K, van Niel EWJ, Willquist K, Svensson SE, Kreuger E. Reduced use of phosphorus and water in sequential dark fermentation and anaerobic digestion of wheat straw and the application of ensiled steam-pretreated lucerne as a macronutrient provider in anaerobic digestion. Biotechnol Biofuels 2018; 11:281. [PMID: 30337960 PMCID: PMC6180601 DOI: 10.1186/s13068-018-1280-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 10/04/2018] [Indexed: 05/14/2023]
Abstract
BACKGROUND Current EU directives demand increased use of renewable fuels in the transportation sector but restrict governmental support for production of biofuels produced from crops. The use of intercropped lucerne and wheat may comply with the directives. In the current study, the combination of ensiled lucerne (Medicago sativa L.) and wheat straw as substrate for hydrogen and methane production was investigated. Steam-pretreated and enzymatically hydrolysed wheat straw [WSH, 76% of total chemical oxygen demand (COD)] and ensiled lucerne (LH, 24% of total COD) were used for sequential hydrogen production through dark fermentation and methane production through anaerobic digestion and directly for anaerobic digestion. Synthetic co-cultures of extreme thermophilic Caldicellulosiruptor species adapted to elevated osmolalities were used for dark fermentation. RESULTS Based on 6 tested steam pretreatment conditions, 5 min at 200 °C was chosen for the ensiled lucerne. The same conditions as applied for wheat straw (10 min at 200 °C with 1% acetic acid) would give similar sugar yields. Volumetric hydrogen productivities of 6.7 and 4.3 mmol/L/h and hydrogen yields of 1.9 and 1.8 mol/mol hexose were observed using WSH and the combination of WSH and LH, respectively, which were relatively low compared to those of the wild-type strains. The combinations of WSH plus LH and the effluent from dark fermentation of WSH plus LH were efficiently converted to methane in anaerobic digestion with COD removal of 85-89% at organic loading rates of COD 5.4 and 8.5 g/L/day, respectively, in UASB reactors. The nutrients in the combined hydrolysates could support this conversion. CONCLUSIONS This study demonstrates the possibility of reducing the water addition to WSH by 26% and the phosphorus addition by 80% in dark fermentation with Caldicellulosiruptor species, compared to previous reports. WSH and combined WSH and LH were well tolerated by osmotolerant co-cultures. The yield was not significantly different when using defined media or hydrolysates with the same concentrations of sugars. However, the sugar concentration was negatively correlated with the hydrogen yield when comparing the results to previous reports. Hydrolysates and effluents from dark fermentation can be efficiently converted to methane. Lucerne can serve as macronutrient provider in anaerobic digestion. Intercropping with wheat is promising.
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Affiliation(s)
- Eoin Byrne
- Division of Applied Microbiology, Dept. of Chemistry, Lund University, PO Box 124, 221 00 Lund, Sweden
| | - Krisztina Kovacs
- Dept. of Chemical Engineering, Lund University, PO Box 124, 221 00 Lund, Sweden
| | - Ed W. J. van Niel
- Division of Applied Microbiology, Dept. of Chemistry, Lund University, PO Box 124, 221 00 Lund, Sweden
| | - Karin Willquist
- RISE, Forskningsbyn Ideon Scheelevägen 27, 223 70 Lund, Sweden
| | - Sven-Erik Svensson
- Dept. of Biosystems and Technology, Swedish University of Agricultural Sciences, PO Box 103, 230 53 Alnarp, Sweden
| | - Emma Kreuger
- Division of Biotechnology, Dept. of Chemistry, Lund University, PO Box 124, 221 00 Lund, Sweden
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11
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Quatrini R, Escudero LV, Moya-Beltrán A, Galleguillos PA, Issotta F, Acosta M, Cárdenas JP, Nuñez H, Salinas K, Holmes DS, Demergasso C. Draft genome sequence of Acidithiobacillus thiooxidans CLST isolated from the acidic hypersaline Gorbea salt flat in northern Chile. Stand Genomic Sci 2017; 12:84. [PMID: 29270251 PMCID: PMC5735861 DOI: 10.1186/s40793-017-0305-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 12/06/2017] [Indexed: 01/16/2023] Open
Abstract
10.1601/nm.2199 CLST is an extremely acidophilic gamma-proteobacteria that was isolated from the Gorbea salt flat, an acidic hypersaline environment in northern Chile. This kind of environment is considered a terrestrial analog of ancient Martian terrains and a source of new material for biotechnological applications. 10.1601/nm.2199 plays a key role in industrial bioleaching; it has the capacity of generating and maintaining acidic conditions by producing sulfuric acid and it can also remove sulfur layers from the surface of minerals, which are detrimental for their dissolution. CLST is a strain of 10.1601/nm.2199 able to tolerate moderate chloride concentrations (up to 15 g L−1 Cl−), a feature that is quite unusual in extreme acidophilic microorganisms. Basic microbiological features and genomic properties of this biotechnologically relevant strain are described in this work. The 3,974,949 bp draft genome is arranged into 40 scaffolds of 389 contigs containing 3866 protein-coding genes and 75 RNAs encoding genes. This is the first draft genome of a halotolerant 10.1601/nm.2199 strain. The release of the genome sequence of this strain improves representation of these extreme acidophilic Gram negative bacteria in public databases and strengthens the framework for further investigation of the physiological diversity and ecological function of 10.1601/nm.2199 populations.
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Affiliation(s)
- Raquel Quatrini
- Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile
| | - Lorena V Escudero
- Centro de Biotecnología "Profesor Alberto Ruiz", Universidad Católica del Norte, 1270709 Antofagasta, Chile.,Centro de Investigación Científica y Tecnológica para la Minería, Antofagasta, Chile
| | - Ana Moya-Beltrán
- Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile
| | - Pedro A Galleguillos
- Centro de Biotecnología "Profesor Alberto Ruiz", Universidad Católica del Norte, 1270709 Antofagasta, Chile.,Centro de Investigación Científica y Tecnológica para la Minería, Antofagasta, Chile
| | | | - Mauricio Acosta
- Centro de Biotecnología "Profesor Alberto Ruiz", Universidad Católica del Norte, 1270709 Antofagasta, Chile
| | | | - Harold Nuñez
- Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile
| | | | - David S Holmes
- Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile.,Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Cecilia Demergasso
- Centro de Biotecnología "Profesor Alberto Ruiz", Universidad Católica del Norte, 1270709 Antofagasta, Chile.,Centro de Investigación Científica y Tecnológica para la Minería, Antofagasta, Chile
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12
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Xiao M, Zhu X, Xu H, Tang J, Liu R, Bi C, Fan F, Zhang X. A novel point mutation in RpoB improves osmotolerance and succinic acid production in Escherichia coli. BMC Biotechnol 2017; 17:10. [PMID: 28193207 PMCID: PMC5307762 DOI: 10.1186/s12896-017-0337-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 02/10/2017] [Indexed: 11/29/2022] Open
Abstract
Background Escherichia coli suffer from osmotic stress during succinic acid (SA) production, which reduces the performance of this microbial factory. Results Here, we report that a point mutation leading to a single amino acid change (D654Y) within the β-subunit of DNA-dependent RNA polymerase (RpoB) significantly improved the osmotolerance of E. coli. Importation of the D654Y mutation of RpoB into the parental strain, Suc-T110, increased cell growth and SA production by more than 40% compared to that of the control under high glucose osmolality. The transcriptome profile, determined by RNA-sequencing, showed two distinct stress responses elicited by the mutated RpoB that counterbalanced the osmotic stress. Under non-stressed conditions, genes involved in the synthesis and transport of compatible solutes such as glycine-betaine, glutamate or proline were upregulated even without osmotic stimulation, suggesting a “pre-defense” mechanism maybe formed in the rpoB mutant. Under osmotic stressed conditions, genes encoding diverse sugar transporters, which should be down-regulated in the presence of high osmotic pressure, were derepressed in the rpoB mutant. Additional genetic experiments showed that enhancing the expression of the mal regulon, especially for genes that encode the glycoporin LamB and maltose transporter, contributed to the osmotolerance phenotype. Conclusions The D654Y single amino acid substitution in RpoB rendered E. coli cells resistant to osmotic stress, probably due to improved cell growth and viability via enhanced sugar uptake under stressed conditions, and activated a potential “pre-defense” mechanism under non-stressed conditions. The findings of this work will be useful for bacterial host improvement to enhance its resistance to osmotic stress and facilitate bio-based organic acids production. Electronic supplementary material The online version of this article (doi:10.1186/s12896-017-0337-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mengyong Xiao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xinna Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Hongtao Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Jinlei Tang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Ru Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Changhao Bi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Feiyu Fan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.
| | - Xueli Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.
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13
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García-Marqués S, Randez-Gil F, Prieto JA. Nuclear versus cytosolic activity of the yeast Hog1 MAP kinase in response to osmotic and tunicamycin-induced ER stress. FEBS Lett 2015; 589:2163-8. [PMID: 26140985 DOI: 10.1016/j.febslet.2015.06.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 06/20/2015] [Indexed: 11/23/2022]
Abstract
We examined the physiological significance of the nuclear versus cytosolic localization of the MAPK Hog1p in the ability of yeast cells to cope with osmotic and ER (endoplasmic reticulum) stress. Our results indicate that nuclear import of Hog1p is not critical for osmoadaptation. Plasma membrane-anchored Hog1p is still able to induce increased expression of GPD1 and glycerol accumulation. This is a key osmoregulatory event, although a small production of the osmolyte coupled with the nuclear import of Hog1p is sufficient to provide osmoresistance. On the contrary, the nuclear activity of Hog1p is dispensable for ER stress adaptation.
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14
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Pal KK, Dey R, Thomas M, Ghorai S, Sherathia D, Vanpariya S, Rupapara R, Rawal P, Mandaliya M, Sukhadiya B, Saxena AK. Draft Genome Sequence of an Extreme Haloarchaeon 3A1-DGR Isolated from a Saltern Crystallizer of the Little Rann of Kutch, India. Indian J Microbiol 2014; 54:471-3. [PMID: 25320448 DOI: 10.1007/s12088-014-0483-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/21/2014] [Indexed: 10/25/2022] Open
Abstract
Haloarchaea are predominant in the salt crystallizers of the Rann of Kutch when the concentration of salts approaches saturation levels. The obligate and extreme halophilic archaeon 3A1-DGR, isolated from a salt crystallizer pond of the Little Rann of Kutch, India, needs minimum of 10 % NaCl in the growth medium. To understand the mechanism(s) of osmotolerance and adaptation at extreme osmolarity, and to mine relevant gene(s), the genome of this haloarchaeon, 3A1-DGR, was sequenced. We report here, the 2.88 Mb draft genome sequence of the haloarchaeon 3A1-DGR, with G+C content of 68 % and the possible involvement of 43 genes in stress tolerance. Further studies of the genome of this haloarchaeon would be required to identify gene(s) that might be responsible for imparting extreme osmotolerance.
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15
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Cebrián G, Arroyo C, Mañas P, Condón S. Bacterial maximum non-inhibitory and minimum inhibitory concentrations of different water activity depressing solutes. Int J Food Microbiol 2014; 188:67-74. [PMID: 25090605 DOI: 10.1016/j.ijfoodmicro.2014.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/09/2014] [Accepted: 07/13/2014] [Indexed: 11/30/2022]
Abstract
The NaCl MNICs (maximum non-inhibitory concentrations) and MICs (minimum inhibitory concentrations) for growth of various strains of six bacterial species were determined and then compared with those obtained for seven other solutes. The influence of prior growth conditions on the MNICs and MICs was also evaluated. No significant changes on the MNICs and MICs were found among the strains studied within each species. Among all factors investigated, only growth phase -for Gram-negatives- and growth at high NaCl concentrations led to a change in the NaCl MNICs. Species could be classified depending on its NaCl MNICs and MICs (in decreasing order) as follows: Staphylococcus aureus, Listeria monocytogenes, Cronobacter sakazakii, Enterococcus faecium, Escherichia coli and Salmonella Typhimurium. Similar results were obtained for KCl, LiCl, and sodium acetate, but not for the remaining solutes investigated (sucrose, glycerol, MgCl2 and CaCl2). Results obtained indicate that, in general, Gram-negatives showed lower MNICs and MICs than Gram-positives for all the solutes, S. aureus being the most solute tolerant microorganism. When compared on a molar basis, glycerol showed the highest MNICs and MICs for all the microorganisms -except for S. aureus- and LiCl the lowest ones. NaCl MNICs and MICs were not significantly different from those of KCl when compared on a molar basis. Therefore, the inhibitory action of NaCl could not be linked to the specific action of Na(+). Results also showed that the Na(+) tolerance of some species was Cl(-) dependent whereas for others it was not, and that factors others than aw-decrease contribute to the inhibitory action of LiCl, CaCl2 and MgCl2.
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Affiliation(s)
- G Cebrián
- Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet, 177, 50013 Zaragoza, Spain.
| | - C Arroyo
- Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet, 177, 50013 Zaragoza, Spain
| | - P Mañas
- Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet, 177, 50013 Zaragoza, Spain
| | - S Condón
- Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, C/Miguel Servet, 177, 50013 Zaragoza, Spain
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16
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Feeney A, Johnston CD, Govender R, O’Mahony J, Coffey A, Sleator RD. Analysis of the role of the Cronobacter sakazakii ProP homologues in osmotolerance. Gut Pathog 2014; 6:15. [PMID: 24910715 PMCID: PMC4047261 DOI: 10.1186/1757-4749-6-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/14/2014] [Indexed: 01/06/2023] Open
Abstract
Bacteria respond to elevated osmolality by the accumulation of a range of low molecular weight molecules, known as compatible solutes (owing to their compatibility with the cells' normal physiology at high internal concentrations). The neonatal pathogen Cronobacter sakazakii is uniquely osmotolerant, surviving in powdered infant formula (PIF) which typically has a water activity (aw) of 0.2 - inhospitable to most micro-organisms. Mortality rates of up to 80% in infected infants have been recorded making C. sakazakii a serious cause for concern. In silico analysis of the C. sakazakii BAA-894 genome revealed seven copies of the osmolyte uptake system ProP. Herein, we test the physiological role of each of these homologues following heterologous expression against an osmosensitive Escherichia coli host.
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Affiliation(s)
- Audrey Feeney
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Christopher D Johnston
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Rodney Govender
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Jim O’Mahony
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Aidan Coffey
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
| | - Roy D Sleator
- Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland
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17
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MIRJALALI H, NIYYATI M, ABEDKHOJASTEH H, BABAEI Z, SHARIFDINI M, REZAEIAN M. Pathogenic assays of acanthamoeba belonging to the t4 genotype. Iran J Parasitol 2013; 8:530-5. [PMID: 25516733 PMCID: PMC4266116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/10/2013] [Indexed: 11/11/2022]
Abstract
BACKGROUND Acanthamoeba genus is introduced as opportunistic and cosmopolitan parasite. Monkey and wistar rat are appropriate models for experimental study on Acanthamoeba infection. In this study Acanthamoeba spp. were isolated from hot spring (HS), windows dust (WD) and a corneal sample of keratitis patient (KP) and their pathogenicity surveyed by in vitro and in vivo tests. METHODS Isolates of Acanthamoeba were cultivated axenically for 12 months in PYG medium. Overall, 30 wistar rats, in 6 equal groups were used for developing experimental Acanthamoeba keratitis (AK) and Granulomatous Amoebic Encephalitis (GAE). The Keratitis and Granulomatous Encephalitis experiments were performed by intrastromal and intranasal inoculation of Acanthamoeba cysts, respectively. Pathogenicity of the three isolates was also evaluated by in vitro test using osmotolerance and temperature tolerance assays. Identification of genotypes were performed by PCR technique and sequencing. RESULT None of the isolates could perform AK and GAE in wistar rats, although all isolates were described as T4 genotype. Isolates obtained from KP and WD could grow only in 30 °C, but not in 37 °C and 40 °C. On the other hand, HS isolate grew in 30 °C and 37 °C but not in 40 °C. Moreover, all of isolate grew in 0.5 M mannitol but not in 1 M and 1.5 M. CONCLUSION T4 isolates with a long-term axenic culture and different factors related to host and parasite may play role in pathogenicity of these free-living amoebae.
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Affiliation(s)
- Hamed MIRJALALI
- Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam NIYYATI
- Dept. of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hoda ABEDKHOJASTEH
- Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra BABAEI
- Dept. of Parasitology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Meysam SHARIFDINI
- Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mostafa REZAEIAN
- Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences, Tehran, Iran,Correspondence
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