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Arabi D, Hamdy O, Mohamed MSM, Abdel-Salam Z, Abdel-Harith M. Discriminating two bacteria via laser-induced breakdown spectroscopy and artificial neural network. AMB Express 2023; 13:61. [PMID: 37338621 DOI: 10.1186/s13568-023-01569-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023] Open
Abstract
Rapid and successful clinical diagnosis and bacterial infection treatment depend on accurate identification and differentiation between different pathogenic bacterial species. A lot of efforts have been made to utilize modern techniques which avoid the laborious work and time-consuming of conventional methods to fulfill this task. Among such techniques, laser-induced breakdown spectroscopy (LIBS) can tell much about bacterial identity and functionality. In the present study, a sensitivity-improved version of LIBS, i.e. nano-enhanced LIBS (NELIBS), has been used to discriminate between two different bacteria (Pseudomonas aeruginosa and Proteus mirabilis) belonging to different taxonomic orders. Biogenic silver nanoparticles (AgNPs) are sprinkled onto the samples' surface to have better discrimination capability of the technique. The obtained spectroscopic results of the NELIBS approach revealed superior differentiation between the two bacterial species compared to the results of the conventional LIBS. Identification of each bacterial species has been achieved in light of the presence of spectral lines of certain elements. On the other hand, the discrimination was successful by comparing the intensity of the spectral lines in the spectra of the two bacteria. In addition, an artificial neural network (ANN) model has been created to assess the variation between the two data sets, affecting the differentiation process. The results revealed that NELIBS provides higher sensitivity and more intense spectral lines with increased detectable elements. The ANN results showed that the accuracy rates are 88% and 92% for LIBS and NELIBS, respectively. In the present work, it has been demonstrated that NELIBS combined with ANN successfully differentiated between both bacteria rapidly with high precision compared to conventional microbiological discrimination techniques and with minimum sample preparation.
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Affiliation(s)
- Dina Arabi
- Laser Applications in Metrology, Photochemistry and Agriculture Department, National Institute of Laser Enhanced Science, Cairo University, Giza, 12613, Egypt
| | - Omnia Hamdy
- Engineering Applications of Lasers Department, National Institute of Laser Enhanced Science, Cairo University, Giza, 12613, Egypt
| | - Mahmoud S M Mohamed
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza, Egypt
| | - Zienab Abdel-Salam
- Laser Applications in Metrology, Photochemistry and Agriculture Department, National Institute of Laser Enhanced Science, Cairo University, Giza, 12613, Egypt
| | - Mohamed Abdel-Harith
- Laser Applications in Metrology, Photochemistry and Agriculture Department, National Institute of Laser Enhanced Science, Cairo University, Giza, 12613, Egypt.
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Establishment of a salt-induced bioremediation platform from marine Vibrio natriegens. Commun Biol 2022; 5:1352. [PMID: 36494435 PMCID: PMC9734156 DOI: 10.1038/s42003-022-04319-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
Industrial wastewater discharge, agricultural production, marine shipping, oil extraction, and other activities have caused serious marine pollution, including microplastics, petroleum and its products, heavy metals, pesticides, and other organics. Efficiency of bioremediation of marine pollutions may be limited by high salt concentrations (>1%, w/v), which can cause an apparent loss of microbial activities. In this study, functional promoters P1, P2-1, and P2-2 censoring salt stress were isolated and identified from a Vibrio natriegens strain Vmax. Three salt-induced degradation models were constructed to degrade polyethylene terephthalate (PET), chlorpyrifos (CP), and hexabromocyclododecanes (HBCDs) using the marine strain Vmax. The engineered strains are efficient for degradation of the corresponding substrates, with the degradation rates at 15 mg/L PET in 8 d, 50 mg/L CP in 24 h, and 1 mg/L HBCDs in 4 h, respectively. In addition, an immobilization strategy for recycling and reusing of engineered strains was realized by expressing the chitin-binding protein GbpA. This study may help answer the usage of rapidly growing marine bacteria such as V. natriegens Vmax to degrade marine pollution efficiently.
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Gabillard-Lefort C, Casey M, Glasgow AMA, Boland F, Kerr O, Marron E, Lyons AM, Gunaratnam C, McElvaney NG, Reeves EP. Trikafta Rescues CFTR and Lowers Monocyte P2X7R-Induced Inflammasome Activation in Cystic Fibrosis. Am J Respir Crit Care Med 2022; 205:783-794. [PMID: 35021019 DOI: 10.1164/rccm.202106-1426oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Cystic Fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene and is characterized by sustained inflammation. Adenosine-5'-Triphosphate (ATP) triggers interleukin (IL)-1β secretion via the P2X7 receptor (P2X7R) and activation of the NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome. OBJECTIVES To explore the effect of the CFTR modulator Trikafta (Elexacaftor/Tezacaftor/Ivacaftor) on CFTR expression and the ATP/P2X7R signaling axis in monocytes and on circulating pro-inflammatory markers. METHODS Inflammatory mediators were detected in blood from 42 patients with CF (PWCF) before and after 3 months of Trikafta therapy. Markers of inflammasome activation and IL-1β secretion were measured in monocytes, and following stimulation with ATP and lipopolysaccharides (LPS) in the presence or absence of the P2X7R inhibitor, A438079. MEASUREMENTS AND MAIN RESULTS P2X7R is overexpressed in CF monocytes and receptor inhibition decreased NLRP3 expression, caspase-1 activation, and IL-1β secretion. In vitro and in vivo, P2X7R expression is regulated by CFTR function and intracellular chloride (Cl-) levels. Trikafta therapy restored CFTR expression yet decreased P2X7R in CF monocytes, resulting in normalized Cl- and potassium efflux, and reduced intracellular calcium levels. CFTR modulator therapy decreased circulating levels of ATP and LPS and reduced inflammasome activation and IL-1β secretion. CONCLUSIONS P2X7R expression is regulated by intracellular Cl- levels, and in CF monocytes promotes inflammasome activation. Trikafta therapy significantly increased CFTR protein expression and reduced ATP/P2X7R -induced inflammasome activation. P2X7R may therefore be a promising target to reduce inflammation in PWCF non-eligible for Trikafta or other CFTR modulator therapy.
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Affiliation(s)
- Claudie Gabillard-Lefort
- Royal College of Surgeons in Ireland, Respiratory Research Division - Dept of Medicine, Dublin, Ireland
| | - Michelle Casey
- Royal College of Surgeons in Ireland, Respiratory Research Division - Dept of Medicine, Dublin, Ireland
| | - Arlene M A Glasgow
- Royal College of Surgeons in Ireland, Respiratory Research Division - Dept of Medicine, Dublin, Ireland
| | - Fiona Boland
- Royal College of Surgeons in Ireland, 8863, Population Health Sciences, Dublin, Ireland
| | - Orla Kerr
- Beaumont Hospital, 57978, Dublin, Ireland
| | | | | | - Cedric Gunaratnam
- Royal College of Surgeons in Ireland, Beaumont Hospital, Respiratory Research Division, Department of Medicine, Dublin, Ireland
| | | | - Emer P Reeves
- Royal College of Surgeons in Ireland, Respiratory Research Division - Dept of Medicine, Dublin, Ireland;
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Pineda LH, Tecuapa-Flores ED, Hernández JG, Thangarasu P, Vázquez Ramos JM. Ruthenium complex of bis(benzimidazole-yl-ethyl)sulfide as chemo-sensor for selective recognition of chloride ion, and its application in real bacterial samples. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Murillo-de-Ozores AR, Chávez-Canales M, de Los Heros P, Gamba G, Castañeda-Bueno M. Physiological Processes Modulated by the Chloride-Sensitive WNK-SPAK/OSR1 Kinase Signaling Pathway and the Cation-Coupled Chloride Cotransporters. Front Physiol 2020; 11:585907. [PMID: 33192599 PMCID: PMC7606576 DOI: 10.3389/fphys.2020.585907] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
The role of Cl– as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl– in signaling is the modulation of the With-No-Lysine (K) (WNK) – STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) – Cation-Coupled Cl–Cotransporters (CCCs) cascade. Binding of a Cl– anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl– release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl– influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl– sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.
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Affiliation(s)
- Adrián Rafael Murillo-de-Ozores
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paola de Los Heros
- Unidad de Investigación UNAM-INC, Research Division, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Cockell CS, McLean CM, Perera L, Aka S, Stevens A, Dickinson AW. Growth of Non-Halophilic Bacteria in the Sodium-Magnesium-Sulfate-Chloride Ion System: Unravelling the Complexities of Ion Interactions in Terrestrial and Extraterrestrial Aqueous Environments. ASTROBIOLOGY 2020; 20:944-955. [PMID: 32434375 DOI: 10.1089/ast.2019.2092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Motivated by an interest in understanding the habitability of aqueous environments on Earth and in extraterrestrial settings, this study investigated the influence of ions in an artificial sodium-magnesium-sulfate-chloride ion system on the growth parameters (lag phase, growth rate, and final cell concentration) of bacteria. These four ions, in different combinations, are key components of many aqueous environments on Earth and elsewhere. We investigated non-halophilic bacteria deliberately to remove the bias of prior adaptations to high concentrations of selected ions so that we could compare the effects of different ions. We tested the hypothesis that water activity determined the growth parameters independent of the ion types. Neither water activity or ionic strength alone could predict growth. However, when ionic strengths were matched, many differences in growth parameters could be explained by the water activity. We suggest that species-specific effects (caused by differences in biochemical and physiological influences), the role of individual ions in cellular processes, and potentially the chaotropicity and kosmotropicity of solutions influenced the growth. Our data show that although extreme combinations of these ions allow for general predictions on the habitability of extraterrestrial aqueous environments, a complex interplay of ionic effects influences the growth and thus the adaptations required for given ion combinations. The data also show that an accurate quantification of the habitability of ocean worlds, such as Europa and Enceladus, can only be made when samples are obtained from these water bodies and the ion combinations are determined.
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Affiliation(s)
- Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Claire-Marie McLean
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Liam Perera
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Salomé Aka
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam Stevens
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew W Dickinson
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
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Wang J, Luo J, Huang W, Liu C, Zeng D, Liu H, Qu X, Liu C, Xiang Y, Qin X. Increased intracellular Cl - concentration by activating FAK promotes airway epithelial BEAS-2B cells proliferation and wound healing. Arch Biochem Biophys 2019; 680:108225. [PMID: 31838119 DOI: 10.1016/j.abb.2019.108225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/10/2019] [Accepted: 12/10/2019] [Indexed: 11/30/2022]
Abstract
An increase in intracellular Cl- concentration ([Cl-]i) may be a general response of airway epithelial cells to various stimuli and may participate in some basic cellular functions. However, whether the basic functional activities of cells, such as proliferation and wound healing, are related to Cl- activities remains unclear. This study aimed to investigate the effects and potential mechanisms of [Cl-]i on the proliferation and wound healing ability of airway epithelial BEAS-2B cells. BEAS-2B cells were treated with four Cl- channel inhibitors (T16Ainh-A01, CFTRinh-172, CaCCinh-A01, and IAA-94), and the Cl- fluorescence probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide was used. Results showed that all Cl- channel inhibitors could increase [Cl-]i in BEAS-2B cells. The increased [Cl-]i induced by Cl- channel inhibitors or clamping [Cl-]i at high levels enhanced the phosphorylation of focal adhesion kinase (FAK) and subsequently promoted the proliferation and wound healing ability of BEAS-2B cells. By contrast, the FAK inhibitor PF573228 abrogated these effects induced by the increased [Cl-]i. FAK also activated the PI3K/AKT signaling pathway. In conclusion, increased [Cl-]i promotes the proliferation and wound healing ability of BEAS-2B cells by activating FAK to activate the PI3K/AKT signaling pathway. Intracellular Cl- may act as a signaling molecule to regulate the proliferation and wound healing ability of airway epithelial cells.
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Affiliation(s)
- Jia Wang
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China; Hunan Provincial People's Hospital, The First-affiliated Hospital of Hunan Normal University, Changsha, 410016, China
| | - Jinhua Luo
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China
| | - Wenjie Huang
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China
| | - Caixia Liu
- College of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Dan Zeng
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China; Hunan Provincial People's Hospital, The First-affiliated Hospital of Hunan Normal University, Changsha, 410016, China
| | - Huijun Liu
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China
| | - Xiangping Qu
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China
| | - Chi Liu
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China
| | - Yang Xiang
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China.
| | - Xiaoqun Qin
- Department of Physiology, School of Basic Medicine, Central South University, Changsha, 410000, China.
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Abstract
Cl- is the major extracellular (Cl-out) and intracellular (Cl-in) anion whose concentration is actively regulated by multiple transporters. These transporters generate Cl- gradients across the plasma membrane and between the cytoplasm and intracellular organelles. [Cl-]in changes rapidly in response to cell stimulation and influences many physiological functions, as well as cellular and systemic homeostasis. However, less appreciated is the signaling function of Cl-. Cl- interacts with multiple proteins to directly modify their activity. This review highlights the signaling function of Cl- and argues that Cl- is a bona fide signaling ion, a function deserving extensive exploration.
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Affiliation(s)
- Benjamin P Lüscher
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Laura Vachel
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
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9
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Valdivieso ÁG, Santa‐Coloma TA. The chloride anion as a signalling effector. Biol Rev Camb Philos Soc 2019; 94:1839-1856. [DOI: 10.1111/brv.12536] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Ángel G. Valdivieso
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED), School of Medical SciencesPontifical Catholic University of Argentina Buenos Aires 1107 Argentina
- The National Scientific and Technical Research Council of Argentina (CONICET) Buenos Aires 1107 Argentina
| | - Tomás A. Santa‐Coloma
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED), School of Medical SciencesPontifical Catholic University of Argentina Buenos Aires 1107 Argentina
- The National Scientific and Technical Research Council of Argentina (CONICET) Buenos Aires 1107 Argentina
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10
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Remonsellez F, Castro-Severyn J, Pardo-Esté C, Aguilar P, Fortt J, Salinas C, Barahona S, León J, Fuentes B, Areche C, Hernández KL, Aguayo D, Saavedra CP. Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium sp. SH31 Isolated From Sediments of Salar de Huasco, Chilean Altiplano. Front Microbiol 2018; 9:2228. [PMID: 30294311 PMCID: PMC6158405 DOI: 10.3389/fmicb.2018.02228] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/31/2018] [Indexed: 12/22/2022] Open
Abstract
Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival.
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Affiliation(s)
- Francisco Remonsellez
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Antofagasta, Chile
| | - Juan Castro-Severyn
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Coral Pardo-Esté
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Pablo Aguilar
- Lake and Glacier Ecology Research Group, Institute of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jonathan Fortt
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Cesar Salinas
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Sergio Barahona
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Joice León
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Bárbara Fuentes
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile
| | - Carlos Areche
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Klaudia L. Hernández
- Centro de Investigación Marina Quintay, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel Aguayo
- Center for Bioinformatics and Integrative Biology, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Claudia P. Saavedra
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
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11
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Jiang H, Jiang M, Yang L, Yao P, Ma L, Wang C, Wang H, Qian G, Hu B, Fan J. The Ribosomal Protein RplY Is Required for Pectobacterium carotovorum Virulence and Is Induced by Zantedeschia elliotiana Extract. PHYTOPATHOLOGY 2017; 107:1322-1330. [PMID: 28853642 DOI: 10.1094/phyto-04-17-0161-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pectobacterium carotovorum subsp. carotovorum strain PccS1, a bacterial pathogen causing soft rot disease of Zantedeschia elliotiana (colored calla), was investigated for virulence genes induced by the host plant. Using a promoter-trap transposon (mariner), we obtained 500 transposon mutants showing kanamycin resistance dependent on extract of Z. elliotiana. One of these mutants, PM86, exhibited attenuated virulence on both Z. elliotiana and Brassica rapa subsp. pekinensis. The growth of PM86 was also reduced in minimal medium (MM), and the reduction was restored by adding plant extract to the MM. The gene containing the insertion site was identified as rplY. The deletion mutant ΔrplY, exhibited reduced virulence, motility and plant cell wall-degrading enzyme production but not biofilm formation. Analysis of gene expression and reporter fusions revealed that the rplY gene in PccS1 is up-regulated at both the transcriptional and the translational levels in the presence of plant extract. Our results suggest that rplY is induced by Z. elliotiana extract and is crucial for virulence in P. carotovorum subsp. carotovorum.
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Affiliation(s)
- Huan Jiang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mengyi Jiang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Liuke Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Peiyan Yao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lin Ma
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunting Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Gouliang Qian
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Baishi Hu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiaqin Fan
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
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12
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Clauzure M, Valdivieso ÁG, Massip-Copiz MM, Mori C, Dugour AV, Figueroa JM, Santa-Coloma TA. Intracellular Chloride Concentration Changes Modulate IL-1β Expression and Secretion in Human Bronchial Epithelial Cultured Cells. J Cell Biochem 2017; 118:2131-2140. [DOI: 10.1002/jcb.25850] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/19/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Mariángeles Clauzure
- Laboratory of Cellular and Molecular Biology, National Scientific and Technical Research Council (CONICET) and School of Medical Sciences, Institute for Biomedical Research (BIOMED); Pontifical Catholic University of Argentina (UCA); Buenos Aires Argentina
| | - Ángel G. Valdivieso
- Laboratory of Cellular and Molecular Biology, National Scientific and Technical Research Council (CONICET) and School of Medical Sciences, Institute for Biomedical Research (BIOMED); Pontifical Catholic University of Argentina (UCA); Buenos Aires Argentina
| | - María M. Massip-Copiz
- Laboratory of Cellular and Molecular Biology, National Scientific and Technical Research Council (CONICET) and School of Medical Sciences, Institute for Biomedical Research (BIOMED); Pontifical Catholic University of Argentina (UCA); Buenos Aires Argentina
| | - Consuelo Mori
- Laboratory of Cellular and Molecular Biology, National Scientific and Technical Research Council (CONICET) and School of Medical Sciences, Institute for Biomedical Research (BIOMED); Pontifical Catholic University of Argentina (UCA); Buenos Aires Argentina
| | | | | | - Tomás A. Santa-Coloma
- Laboratory of Cellular and Molecular Biology, National Scientific and Technical Research Council (CONICET) and School of Medical Sciences, Institute for Biomedical Research (BIOMED); Pontifical Catholic University of Argentina (UCA); Buenos Aires Argentina
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Gallardo K, Candia JE, Remonsellez F, Escudero LV, Demergasso CS. The Ecological Coherence of Temperature and Salinity Tolerance Interaction and Pigmentation in a Non-marine Vibrio Isolated from Salar de Atacama. Front Microbiol 2016; 7:1943. [PMID: 27990141 PMCID: PMC5130992 DOI: 10.3389/fmicb.2016.01943] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 11/18/2016] [Indexed: 12/17/2022] Open
Abstract
The occurrence of microorganisms from the Vibrio genus in saline lakes from northern Chile had been evidenced using Numerical Taxonomy decades before and, more recently, by phylogenetic analyses of environmental samples and isolates. Most of the knowledge about this genus came from marine isolates and showed temperature and salinity to be integral agents in shaping the niche of the Vibrio populations. The stress tolerance phenotypes of Vibrio sp. Teb5a1 isolated from Salar de Atacama was investigated. It was able to grow without NaCl and tolerated up to 100 g/L of the salt. Furthermore, it grew between 17° and 49°C (optimum 30°C) in the absence of NaCl, and the range was expanded into cold temperature (4–49°C) in the presence of the salt. Other additional adaptive strategies were observed in response to the osmotic stress: pigment production, identified as the known antibacterial prodigiosin, swimming and swarming motility and synthesis of a polar flagellum. It is possible to infer that environmental congruence might explain the cellular phenotypes observed in Vibrio sp. considering that coupling between temperature and salinity tolerance, the production of antibacterial agents at higher temperatures, flagellation and motility increase the chance of Vibrio sp. to survive in salty environments with high daily temperature swings and UV radiation.
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Affiliation(s)
- Karem Gallardo
- Centro de Biotecnología, Universidad Católica del Norte Antofagasta, Chile
| | - Jonathan E Candia
- Centro de Biotecnología, Universidad Católica del Norte Antofagasta, Chile
| | - Francisco Remonsellez
- Departamento de Ingeniería Química, Universidad Católica del Norte Antofagasta, Chile
| | - Lorena V Escudero
- Centro de Biotecnología, Universidad Católica del NorteAntofagasta, Chile; Centro de Investigación Científico Tecnológico para la MineríaAntofagasta, Chile
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Yaakop AS, Chan KG, Ee R, Lim YL, Lee SK, Manan FA, Goh KM. Characterization of the mechanism of prolonged adaptation to osmotic stress of Jeotgalibacillus malaysiensis via genome and transcriptome sequencing analyses. Sci Rep 2016; 6:33660. [PMID: 27641516 PMCID: PMC5027565 DOI: 10.1038/srep33660] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/31/2016] [Indexed: 11/21/2022] Open
Abstract
Jeotgalibacillus malaysiensis, a moderate halophilic bacterium isolated from a pelagic area, can endure higher concentrations of sodium chloride (NaCl) than other Jeotgalibacillus type strains. In this study, we therefore chose to sequence and assemble the entire J. malaysiensis genome. This is the first report to provide a detailed analysis of the genomic features of J. malaysiensis, and to perform genetic comparisons between this microorganism and other halophiles. J. malaysiensis encodes a native megaplasmid (pJeoMA), which is greater than 600 kilobases in size, that is absent from other sequenced species of Jeotgalibacillus. Subsequently, RNA-Seq-based transcriptome analysis was utilised to examine adaptations of J. malaysiensis to osmotic stress. Specifically, the eggNOG (evolutionary genealogy of genes: Non-supervised Orthologous Groups) and KEGG (Kyoto Encyclopaedia of Genes and Genomes) databases were used to elucidate the overall effects of osmotic stress on the organism. Generally, saline stress significantly affected carbohydrate, energy, and amino acid metabolism, as well as fatty acid biosynthesis. Our findings also indicate that J. malaysiensis adopted a combination of approaches, including the uptake or synthesis of osmoprotectants, for surviving salt stress. Among these, proline synthesis appeared to be the preferred method for withstanding prolonged osmotic stress in J. malaysiensis.
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Affiliation(s)
- Amira Suriaty Yaakop
- Universiti Teknologi Malaysia, Faculty of Biosciences and Medical Engineering, 81300 Skudai, Johor, Malaysia
| | - Kok-Gan Chan
- University of Malaya, Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, 50603 Kuala Lumpur, Malaysia
| | - Robson Ee
- University of Malaya, Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, 50603 Kuala Lumpur, Malaysia
| | - Yan Lue Lim
- University of Malaya, Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, 50603 Kuala Lumpur, Malaysia
| | - Siew-Kim Lee
- University of Malaya, Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, 50603 Kuala Lumpur, Malaysia
| | - Fazilah Abd Manan
- Universiti Teknologi Malaysia, Faculty of Biosciences and Medical Engineering, 81300 Skudai, Johor, Malaysia
| | - Kian Mau Goh
- Universiti Teknologi Malaysia, Faculty of Biosciences and Medical Engineering, 81300 Skudai, Johor, Malaysia
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Hashmi MZ, Qin Z, Yao X, Ahmed Z, Xiaomei S, Shen C, Tang X. PCBs attenuation and abundance of Dehalococcoides spp., bphC, CheA, and flic genes in typical polychlorinated biphenyl-polluted soil under floody and dry soil conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3907-3913. [PMID: 26503002 DOI: 10.1007/s11356-015-5577-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
This study investigates PCBs attenuation and the abundance of active polychlorinated-degrading Dehalococcoides spp. biphenyl dioxygenase (bphC), chemotaxis (CheA), and flagellum (flic) genes in floody and dry soil conditions polluted with polychlorinated biphenyls. The results revealed that total PCBs, high chlorinated PCBs (>4 cl), and less chlorinated PCBs (<4 cl) decreased with the passage of time in floody and dry soil conditions. The reduction of total PCBs (13.87%) and less chlorinated PCBs (15.39%) was more in dry soil than floody soil, while high chlorinated PCBs showed more reduction in floody soil (8.06%) than dry soil. Dehaloccoides spp., bphC, CheA, and flic genes indicated temporal dynamics in abundance in floody and dry soil conditions. The highest abundance was 1.6 × 10(9), 3.7 × 10(4), and 3.6 × 10(2) copies in floody and 1.6 × 10(4) copies in dry soil for Dehalococcoides spp., bphC, CheA, and flic, respectively. Multivariate statistics (RDA) revealed that Dehaloccoides spp. were positively influenced by the higher chlorinated PCBs and soil physical properties, CheA gene with floody soil, flic gene with total PCBs and less chlorinated PCBs, and bphC gene was affected with moisture contents and less chlorinated PCBs. This study provides new insight in the attenuation of PCBs and the abundance of active Dehalococcoides spp. and genes in PCBs polluted soil under floody and dry soil conditions.
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Affiliation(s)
- Muhammad Zaffar Hashmi
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
- Department of Meteorology, COMSATS Institute of Information Technology, Park road, Islamabad, Pakistan
- Institute of Health and Management Sciences, Green Avenue, Park Road, Islamabad, Pakistan
| | - Zhihui Qin
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Xiaoyan Yao
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Zulkifl Ahmed
- Department of Building and Architecture Engineering, Bahauddin Zakariya University, Multan, Pakistan
| | - Su Xiaomei
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Chaofeng Shen
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China
| | - Xianjin Tang
- College of Environmental and Natural Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, Zhejiang, People's Republic of China.
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Salt Stress Induced Changes in the Exoproteome of the Halotolerant Bacterium Tistlia consotensis Deciphered by Proteogenomics. PLoS One 2015; 10:e0135065. [PMID: 26287734 PMCID: PMC4545795 DOI: 10.1371/journal.pone.0135065] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 07/16/2015] [Indexed: 11/19/2022] Open
Abstract
The ability of bacteria to adapt to external osmotic changes is fundamental for their survival. Halotolerant microorganisms, such as Tistlia consotensis, have to cope with continuous fluctuations in the salinity of their natural environments which require effective adaptation strategies against salt stress. Changes of extracellular protein profiles from Tistlia consotensis in conditions of low and high salinities were monitored by proteogenomics using a bacterial draft genome. At low salinity, we detected greater amounts of the HpnM protein which is involved in the biosynthesis of hopanoids. This may represent a novel, and previously unreported, strategy by halotolerant microorganisms to prevent the entry of water into the cell under conditions of low salinity. At high salinity, proteins associated with osmosensing, exclusion of Na+ and transport of compatible solutes, such as glycine betaine or proline are abundant. We also found that, probably in response to the high salt concentration, T. consotensis activated the synthesis of flagella and triggered a chemotactic response neither of which were observed at the salt concentration which is optimal for growth. Our study demonstrates that the exoproteome is an appropriate indicator of adaptive response of T. consotensis to changes in salinity because it allowed the identification of key proteins within its osmoadaptive mechanism that had not previously been detected in its cell proteome.
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Shiyan A, Thompson M, Köcher S, Tausendschön M, Santos H, Hänelt I, Müller V. Glutamine synthetase 2 is not essential for biosynthesis of compatible solutes in Halobacillus halophilus. Front Microbiol 2014; 5:168. [PMID: 24782854 PMCID: PMC3995056 DOI: 10.3389/fmicb.2014.00168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/27/2014] [Indexed: 11/13/2022] Open
Abstract
Halobacillus halophilus, a moderately halophilic bacterium isolated from salt marshes, produces various compatible solutes to cope with osmotic stress. Glutamate and glutamine are dominant compatible solutes at mild salinities. Glutamine synthetase activity in cell suspensions of Halobacillus halophilus wild type was shown to be salt dependent and chloride modulated. A possible candidate to catalyze glutamine synthesis is glutamine synthetase A2, whose transcription is stimulated by chloride. To address the role of GlnA2 in the biosynthesis of the osmolytes glutamate and glutamine, a deletion mutant (ΔglnA2) was generated and characterized in detail. We compared the pool of compatible solutes and performed transcriptional analyses of the principal genes controlling the solute production in the wild type strain and the deletion mutant. These measurements did not confirm the hypothesized role of GlnA2 in the osmolyte production. Most likely the presence of another, yet to be identified enzyme has the main contribution in the measured activity in crude extracts and probably determines the total chloride-modulated profile. The role of GlnA2 remains to be elucidated.
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Affiliation(s)
- Anna Shiyan
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
| | - Melanie Thompson
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
| | - Saskia Köcher
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
| | - Michaela Tausendschön
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
| | - Helena Santos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
| | - Inga Hänelt
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
| | - Volker Müller
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University of Frankfurt am Main Frankfurt am Main, Germany
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18
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Molecular Mechanisms of Adaptation of the Moderately Halophilic Bacterium Halobacillis halophilus to Its Environment. Life (Basel) 2013; 3:234-43. [PMID: 25371341 PMCID: PMC4187189 DOI: 10.3390/life3010234] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/02/2013] [Accepted: 02/05/2013] [Indexed: 11/16/2022] Open
Abstract
The capability of osmoadaptation is a prerequisite of organisms that live in an environment with changing salinities. Halobacillus halophilus is a moderately halophilic bacterium that grows between 0.4 and 3 M NaCl by accumulating both chloride and compatible solutes as osmolytes. Chloride is absolutely essential for growth and, moreover, was shown to modulate gene expression and activity of enzymes involved in osmoadaptation. The synthesis of different compatible solutes is strictly salinity- and growth phase-dependent. This unique hybrid strategy of H. halophilus will be reviewed here taking into account the recently published genome sequence. Based on identified genes we will speculate about possible scenarios of the synthesis of compatible solutes and the uptake of potassium ion which would complete our knowledge of the fine-tuned osmoregulation and intracellular osmolyte balance in H. halophilus.
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Salgaonkar BB, Mani K, Braganca JM. Characterization of polyhydroxyalkanoates accumulated by a moderately halophilic salt pan isolate Bacillus megaterium strain H16. J Appl Microbiol 2013; 114:1347-56. [PMID: 23311612 DOI: 10.1111/jam.12135] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 12/21/2012] [Accepted: 01/02/2013] [Indexed: 11/28/2022]
Abstract
AIM Characterization of polyhydroxyalkanoates (PHA) accumulated by halophilic bacteria isolated from solar salterns. METHODS AND RESULTS Twenty-six halophilic isolates were obtained from solar salterns of Goa, India. They were screened for accumulation of PHA by Sudan black B, Nile blue A and Nile red stains. Strains H15, H16 and H26 were selected based on their intensity of Nile blue A/Nile red fluorescence. On the basis of phenotypic and genotypic characterization, the three isolates were identified as Bacillus megaterium. Growth kinetics and polymer accumulating capacity of strain H16 were studied in E2 mineral media with 2% glucose with/without NaCl. In the absence of NaCl, strain H16 accumulated PHA to 40·0% (w/w) of cell dry weight (CDW) at 42 h of growth, whereas in presence of 5% w/v NaCl, the culture showed longer lag phase of up to 24 h and accumulated a maximum PHA of 39% (w/w) CDW at 54 h of growth. The infrared spectra of both the polymers exhibited peaks at 1733·9 cm(-1) characteristic of C=O. Scans of (1) H nuclear magnetic resonance (NMR) showed a doublet at 2·5 ppm corresponding to methylene group (-CH(2)), the signal at 5·3 ppm corresponded to methine group (-CH-), and another signal at 1·3 ppm corresponded to the methyl group (-CH(3)). Scans of (13)C NMR showed prominent peaks at 20, 40, 67-68 and 170 ppm, indicating the polymer to be homopolymer of 3-hydroxybutyrates. The polymer is stable up to a temperature of 160°C. CONCLUSION Three moderately halophilic isolates (strain H15, H16 and H26) capable of accumulating PHA were isolated from solar salterns of Ribandar Goa, India, and identified as B. megaterium based on phenotypic and genotypic characterization. Strain H16 accumulated polyhydroxybutyrate in the presence and absence of NaCl up to 40% of its CDW. SIGNIFICANCE AND IMPACT OF THE STUDY This strain would be better suited for production of PHA at industrial level due to its tolerance to high concentration of NaCl.
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Affiliation(s)
- B B Salgaonkar
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, K K Birla Goa Campus, Zuarinagar, Goa, India
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Lopalco P, Angelini R, Lobasso S, Köcher S, Thompson M, Müller V, Corcelli A. Adjusting membrane lipids under salt stress: the case of the moderate halophilic organism Halobacillus halophilus. Environ Microbiol 2012; 15:1078-87. [PMID: 22970819 DOI: 10.1111/j.1462-2920.2012.02870.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/06/2012] [Accepted: 08/08/2012] [Indexed: 11/28/2022]
Abstract
The lipid composition of Halobacillus halophilus was investigated by combined thin-layer chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses of the total lipid extract. Main polar lipids were found to be sulfoquinovosyldiacylglycerol and phosphatidylglycerol, while cardiolipin was a minor lipid together with phosphatidic acid, alanyl-phosphatidylglycerol and two not yet fully identified lipid components. In addition the analyses of residual lipids, associated with denatured proteins after the lipid extraction, revealed the presence of significant amounts of cardiolipin, indicating that it is a not readily extractable phospholipid. Post decay source mass spectrometry analyses allowed the determination of acyl chains of main lipid components. On increasing the culture medium salinity, an increase in the shorter chains and the presence of chain unsaturations were observed. These changes in the lipid core structures might compensate for the increase in packing and rigidity of phospholipid and sulfoglycolipid polar heads in high-salt medium, therefore contributing to the homeostasis of membrane fluidity and permeability in salt stress conditions.
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Affiliation(s)
- Patrizia Lopalco
- Institute for Microelectronics and Microsystems, National Research Council (IMM-CNR), Lecce, Italy
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21
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Saum SH, Pfeiffer F, Palm P, Rampp M, Schuster SC, Müller V, Oesterhelt D. Chloride and organic osmolytes: a hybrid strategy to cope with elevated salinities by the moderately halophilic, chloride-dependent bacteriumHalobacillus halophilus. Environ Microbiol 2012; 15:1619-33. [DOI: 10.1111/j.1462-2920.2012.02770.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Life under multiple extreme conditions: diversity and physiology of the halophilic alkalithermophiles. Appl Environ Microbiol 2012; 78:4074-82. [PMID: 22492435 DOI: 10.1128/aem.00050-12] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Around the world, there are numerous alkaline, hypersaline environments that are heated either geothermally or through intense solar radiation. It was once thought that such harsh environments were inhospitable and incapable of supporting a variety of life. However, numerous culture-dependent and -independent studies revealed the presence of an extensive diversity of aerobic and anaerobic bacteria and archaea that survive and grow under these multiple harsh conditions. This diversity includes the halophilic alkalithermophiles, a novel group of polyextremophiles that require for growth and proliferation the multiple extremes of high salinity, alkaline pH, and elevated temperature. Life under these conditions undoubtedly involves the development of unique physiological characteristics, phenotypic properties, and adaptive mechanisms that enable control of membrane permeability, control of intracellular osmotic balance, and stability of the cell wall, intracellular proteins, and other cellular constituents. This minireview highlights the ecology and growth characteristics of the extremely halophilic alkalithermophiles that have been isolated thus far. Biochemical, metabolic, and physiological properties of the extremely halophilic alkalithermophiles are described, and their roles in resistance to the combined stressors of high salinity, alkaline pH, and high temperature are discussed. The isolation of halophilic alkalithermophiles broadens the physicochemical boundaries for life and extends the boundaries for the combinations of the maximum salinity, pH, and temperature that can support microbial growth.
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Köcher S, Tausendschön M, Thompson M, Saum SH, Müller V. Proline metabolism in the moderately halophilic bacterium Halobacillus halophilus: differential regulation of isogenes in proline utilization. ENVIRONMENTAL MICROBIOLOGY REPORTS 2011; 3:443-448. [PMID: 23761306 DOI: 10.1111/j.1758-2229.2010.00214.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The amino acid proline is not only synthesized as a compatible solute but also used as a carbon and energy source by the moderately halophilic bacterium Halobacillus halophilus. Growth on proline was not affected by the salinity of the medium. Proline was degraded by proline dehydrogenase (ProDH) and Δ(1) -pyrroline-5-carboxylate dehydrogenase (P5CDH) to glutamate via Δ(1) -pyrroline-5-carboxylate. The basic biochemical parameters for ProDH and P5CDH activities were obtained for both in cell free extracts. The encoding genes were identified. H. halophilus has two isogenes each for prodh and p5cdh. prodh2 and p5cdh2 form an operon (put operon) whose mRNA is highly abundant in proline-grown cells. Expression of the put operon was also upregulated by salinity and late growth phase in glucose-grown cells. Similarly, ProDH and P5CDH activities increased in late exponential growth phase. This observation is in line with the previous notion that the compatible solute proline is degraded in stationary phase (in glucose grown cultures).
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Affiliation(s)
- Saskia Köcher
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
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24
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Extremophiles: from abyssal to terrestrial ecosystems and possibly beyond. Naturwissenschaften 2011; 98:253-79. [DOI: 10.1007/s00114-011-0775-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 02/17/2011] [Accepted: 02/18/2011] [Indexed: 01/27/2023]
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Köcher S, Averhoff B, Müller V. Development of a genetic system for the moderately halophilic bacterium Halobacillus halophilus: generation and characterization of mutants defect in the production of the compatible solute proline. Environ Microbiol 2011; 13:2122-31. [PMID: 21366817 DOI: 10.1111/j.1462-2920.2011.02437.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A procedure for markerless mutagenesis gene deletions was developed for the moderately halophilic model strain Halobacillus halophilus. Gene transfer was achieved by protoplast fusion and allelic replacement by a two-step procedure. In the first step the non-replicating plasmid integrated over the upstream or the downstream region of the target gene or operon into the chromosome to obtain single-crossover mutants. When cells were grown under non-selective conditions a second homologous recombination happened (segregation). This resulted in either the wild-type or the mutated allele. The method was used to delete the proHJA operon from H. halophilus. The mutant still produced proline and thus was not proline auxotroph but it completely lost the ability to produce proline as a compatible solute. However, growth was not impaired and the loss of the solute proline was compensated for by an increase in glutamate, glutamine and ectoine concentration. Expressions of the genes encoding the biosynthesis enzymes of theses solutes were upregulated and the activity of the key enzyme in glutamine biosynthesis, the glutamine synthetase, was increased. A model for the proline biosynthesis in the ΔproHJA mutant is discussed.
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Affiliation(s)
- Saskia Köcher
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
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Averhoff B, Müller V. Exploring research frontiers in microbiology: recent advances in halophilic and thermophilic extremophiles. Res Microbiol 2010; 161:506-14. [DOI: 10.1016/j.resmic.2010.05.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 05/05/2010] [Accepted: 05/11/2010] [Indexed: 11/16/2022]
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Saum SH, Müller V. Regulation of osmoadaptation in the moderate halophile Halobacillus halophilus: chloride, glutamate and switching osmolyte strategies. SALINE SYSTEMS 2008; 4:4. [PMID: 18442383 PMCID: PMC2412884 DOI: 10.1186/1746-1448-4-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 04/28/2008] [Indexed: 11/10/2022]
Abstract
The moderate halophile Halobacillus halophilus is the paradigm for chloride dependent growth in prokaryotes. Recent experiments shed light on the molecular basis of the chloride dependence that is reviewed here. In the presence of moderate salinities Halobacillus halophilus mainly accumulates glutamine and glutamate to adjust turgor. The transcription of glnA2 (encoding a glutamine synthetase) as well as the glutamine synthetase activity were identified as chloride dependent steps. Halobacillus halophilus switches its osmolyte strategy and produces proline as the main compatible solute at high salinities. Furthermore, Halobacillus halophilus also shifts its osmolyte strategy at the transition from the exponential to the stationary phase where proline is exchanged by ectoine. Glutamate was found as a "second messenger" essential for proline production. This observation leads to a new model of sensing salinity by sensing the physico-chemical properties of different anions.
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Affiliation(s)
- Stephan H Saum
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany.
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28
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Saum SH, Müller V. Growth phase-dependent switch in osmolyte strategy in a moderate halophile: ectoine is a minor osmolyte but major stationary phase solute in Halobacillus halophilus. Environ Microbiol 2007; 10:716-26. [PMID: 18093162 DOI: 10.1111/j.1462-2920.2007.01494.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The moderately halophilic, chloride-dependent bacterium Halobacillus halophilus switches its osmolyte strategy with the salinity in its environment by the production of different compatible solutes. Ectoine is produced predominantly at very high salinities, along with proline. Interestingly, ectoine production is growth phase dependent which led to a more than 1000-fold change in the ectoine : proline ratio from 0.04 in exponential to 27.4 in late stationary phase cultures. The genes encoding the ectoine biosynthesis pathway were identified on the chromosome in the order ectABC. They form an operon that is expressed in a salinity-dependent manner with low-level expression below 1.5 M NaCl but 10-fold and 23-fold increased expression at 2.5 and 3.0 M NaCl respectively. The temporal expression of genes involved in osmoresponse is different with gdh/gln and pro genes being first, followed by ect genes. Chloride had no effect on expression of ect genes, but stimulated cellular EctC synthesis as well as ectoine production. These data demonstrate, for the first time, a growth-phase dependent switch in osmolyte strategy in a moderate halophile and, additionally, represent another piece of the chloride regulon of H. halophilus.
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Affiliation(s)
- Stephan H Saum
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
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Saum SH, Müller V. Salinity-dependent switching of osmolyte strategies in a moderately halophilic bacterium: glutamate induces proline biosynthesis in Halobacillus halophilus. J Bacteriol 2007; 189:6968-75. [PMID: 17660292 PMCID: PMC2045198 DOI: 10.1128/jb.00775-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The moderately halophilic bacterium Halobacillus halophilus copes with the salinity in its environment by the production of compatible solutes. At intermediate salinities of around 1 M NaCl, cells produce glutamate and glutamine in a chloride-dependent manner (S. H. Saum, J. F. Sydow, P. Palm, F. Pfeiffer, D. Oesterhelt, and V. Müller, J. Bacteriol. 188:6808-6815, 2006). Here, we report that H. halophilus switches its osmolyte strategy and produces proline as the dominant solute at higher salinities (2 to 3 M NaCl). The proline biosynthesis genes proH, proJ, and proA were identified. They form a transcriptional unit and encode the pyrroline-5-carboxylate reductase, the glutamate-5-kinase, and the glutamate-5-semialdehyde dehydrogenase, respectively, catalyzing proline biosynthesis from glutamate. Expression of the genes was clearly salinity dependent and reached a maximum at 2.5 M NaCl, indicating that the pro operon is involved in salinity-induced proline biosynthesis. To address the role of anions in the process of pro gene activation and proline biosynthesis, we used a cell suspension system. Chloride salts lead to the highest accumulation of proline. Interestingly, chloride could be substituted to a large extent by glutamate salts. This unexpected finding was further analyzed on the transcriptional level. The cellular mRNA levels of all three pro genes were increased up to 90-fold in the presence of glutamate. A titration revealed that a minimal concentration of 0.2 M glutamate already stimulated pro gene expression. These data demonstrate that the solute glutamate is involved in the switch of osmolyte strategy from glutamate to proline as the dominant compatible solute during the transition from moderate to high salinity.
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Affiliation(s)
- Stephan H Saum
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
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Saum SH, Roessler M, Koller C, Sydow JF, Müller V. Glutamate restores growth but not motility in the absence of chloride in the moderate halophile Halobacillus halophilus. Extremophiles 2007; 11:711-7. [PMID: 17565428 DOI: 10.1007/s00792-007-0090-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 04/23/2007] [Indexed: 10/23/2022]
Abstract
Halobacillus halophilus is a strictly chloride-dependent, moderately halophilic bacterium that synthesizes glutamate and glutamine as the major compatible solutes at intermediate NaCl concentrations. The key enzyme in production of the compatible solutes glutamine and glutamate, glutamine synthetase, is dependent on chloride on a transcriptional and activity level. This led us to ask whether exogenous supply of glutamate may relief the chloride dependence of growth of H. halophilus. Growth of H. halophilus in minimal medium at 1 M NaCl was stimulated by exogenous glutamate and transport experiments revealed a chloride-independent glutamate uptake by whole cells. Growth was largely impaired in the absence of chloride and, at the same time, glutamate and glutamine pools were reduced by 90%. Exogenous glutamate fully restored growth, and cellular glutamate and glutamine pools were refilled. Although glutamate could restore growth in the absence of chloride, another chloride-dependent process, flagellum synthesis and motility, was not restored by glutamate. The differential effect of glutamate on the two chloride-dependent processes, growth and motility, indicates that glutamate can not substitute chloride in general but apparently bypasses one function of the chloride regulon, the adjustment of pool sizes of compatible solutes.
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Affiliation(s)
- Stephan H Saum
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Max-von-Laue-Str. 9, 60438, Frankfurt am Main, Germany
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Sewald X, Saum SH, Palm P, Pfeiffer F, Oesterhelt D, Müller V. Autoinducer-2-producing protein LuxS, a novel salt- and chloride-induced protein in the moderately halophilic bacterium Halobacillus halophilus. Appl Environ Microbiol 2006; 73:371-9. [PMID: 17085700 PMCID: PMC1796989 DOI: 10.1128/aem.01625-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The moderately halophilic bacterium Halobacillus halophilus carries a homologue of LuxS, a protein involved in the activated methyl cycle and the production of autoinducer-2, which mediates quorum sensing between certain species. luxS of H. halophilus is part of an operon that encodes an S-adenosylmethionine-dependent methyltransferase, a cysteine synthase, and a beta-cystathionine lyase. Expression of luxS was growth phase dependent, with maximal expression in the mid-exponential growth phase. In addition, transcription of luxS was strictly salt dependent; maximal mRNA concentrations were observed with 2.0 M NaCl in the growth medium. Chloride ions stimulated luxS transcription by a factor of three. Western blot analyses demonstrated a growth phase- and salinity-dependent production of LuxS. Moreover, cellular LuxS levels were strictly chloride dependent. Maximal accumulation of LuxS was observed at 0.5 to 1.0 M Cl(-) and depended on the salinity.
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Affiliation(s)
- Xaver Sewald
- Section Microbiology, Department Biology I, Ludwig Maximilians University, Munich, Germany
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Saum SH, Sydow JF, Palm P, Pfeiffer F, Oesterhelt D, Müller V. Biochemical and molecular characterization of the biosynthesis of glutamine and glutamate, two major compatible solutes in the moderately halophilic bacterium Halobacillus halophilus. J Bacteriol 2006; 188:6808-15. [PMID: 16980483 PMCID: PMC1595520 DOI: 10.1128/jb.00781-06] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The moderately halophilic, chloride-dependent bacterium Halobacillus halophilus produces glutamate and glutamine as main compatible solutes at external salinities of 1.0 to 1.5 M NaCl. The routes for the biosynthesis of these solutes and their regulation were examined. The genome contains two genes potentially encoding glutamate dehydrogenases and two genes for the small subunit of a glutamate synthase, but only one gene for the large subunit. However, the expression of these genes was not salt dependent, nor were the corresponding enzymatic activities detectable in cell extracts of cells grown at different salinities. In contrast, glutamine synthetase activity was readily detectable in H. halophilus. Induction of glutamine synthetase activity was strictly salt dependent and reached a maximum at 3.0 M NaCl; chloride stimulated the production of active enzyme by about 300%. Two potential genes encoding a glutamine synthetase, glnA1 and glnA2, were identified. The expression of glnA2 but not of glnA1 was increased up to fourfold in cells adapted to high salt, indicating that GlnA2 is the glutamine synthetase involved in the synthesis of the solutes glutamate and glutamine. Furthermore, expression of glnA2 was stimulated twofold by the presence of chloride ions. Chloride exerted an even more pronounced effect on the enzymatic activity of preformed enzyme: in the absence of chloride in the assay buffer, glutamine synthetase activity was decreased by as much as 90%. These data demonstrate for the first time a regulatory role of a component of common salt, chloride, in the biosynthesis of compatible solutes.
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Affiliation(s)
- Stephan H Saum
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
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Loughman JA, Caparon M. Regulation of SpeB in Streptococcus pyogenes by pH and NaCl: a model for in vivo gene expression. J Bacteriol 2006; 188:399-408. [PMID: 16385029 PMCID: PMC1347310 DOI: 10.1128/jb.188.2.399-408.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For a pathogen such as Streptococcus pyogenes, ecological success is determined by its ability to sense the environment and mount an appropriate adaptive transcriptional response. Thus, determining conditions for analyses of gene expression in vitro that are representative of the in vivo environment is critical for understanding the contributions of transcriptional response pathways to pathogenesis. In this study, we determined that the gene encoding the SpeB cysteine protease is up-regulated over the course of infection in a murine soft-tissue model. Conditions were identified, including growth phase, acidic pH, and an NaCl concentration of <0.1 M, that were required for expression of speB in vitro. Analysis of global expression profiles in response to these conditions in vitro identified a set of coregulated genes whose expression patterns showed a significant correlation with that of speB when examined during infection of murine soft tissues. This analysis revealed that a culture medium that promotes high levels of SpeB expression in vitro produced an expression profile that showed significant correlation to the profile observed in vivo. Taken together, these studies establish culture conditions that mimic in vivo expression patterns; that growth phase, pH, and NaCl may mimic relevant cues sensed by S. pyogenes during infection; and that identification of other environmental cues that alter expression of speB in vitro may provide insight into the signals that direct global patterns of gene expression in vivo.
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Affiliation(s)
- Jennifer A Loughman
- Department of Molecular Microbiology, Washington University School of Medicine, Box 8230, St. Louis, MO 63110-1093, USA
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Affiliation(s)
- Lawrence P Wackett
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, St. Paul, Minnesota 55108, USA.
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Soutourina OA, Bertin PN. Regulation cascade of flagellar expression in Gram-negative bacteria. FEMS Microbiol Rev 2003; 27:505-23. [PMID: 14550943 DOI: 10.1016/s0168-6445(03)00064-0] [Citation(s) in RCA: 256] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Flagellar motility helps bacteria to reach the most favourable environments and to successfully compete with other micro-organisms. These complex organelles also play an important role in adhesion to substrates, biofilm formation and virulence process. In addition, because their synthesis and functioning are very expensive for the cell (about 2% of biosynthetic energy expenditure in Escherichia coli) and may induce a strong immune response in the host organism, the expression of flagellar genes is highly regulated by environmental conditions. In the past few years, many data have been published about the regulation of motility in polarly and laterally flagellated bacteria. However, the mechanism of motility control by environmental factors and by some regulatory proteins remains largely unknown. In this respect, recent experimental data suggest that the master regulatory protein-encoding genes at the first level of the cascade are the main target for many environmental factors. This mechanism might require DNA topology alterations of their regulatory regions. Finally, despite some differences the polar and lateral flagellar cascades share many functional similarities, including a similar hierarchical organisation of flagellar systems. The remarkable parallelism in the functional organisation of flagellar systems suggests an evolutionary conservation of regulatory mechanisms in Gram-negative bacteria.
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Affiliation(s)
- Olga A Soutourina
- Laboratoire de Biochimie, UMR 7654, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex, France
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Abstract
Chloride is an abundant anion on earth but studies analyzing a possible function of chloride in prokaryotes are scarce. To address the question, we have tested 44 different Gram-negative and Gram-positive bacteria for a chloride dependence or chloride stimulation of growth. None required chloride for growth at their optimal growth (salt) conditions. However, in hyperosmotic media containing high concentrations of Na+, 11 bacteria (Aeromonas hydrophila, Bacillus megaterium, Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, Paracoccus denitrificans, Proteus mirabilis, Proteus vulgaris, Staphylococcus aureus, Thermus thermophilus, and Vibrio fischeri) had a strict chloride dependence for growth or were significantly stimulated by chloride. These data show that chloride is essential for growth at high salt (Na+) concentrations in various species of the domain Bacteria.
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Affiliation(s)
- Markus Roessler
- Section Microbiology, Department Biology I, Ludwig-Maximilians-Universität München, Maria-Ward-Str. 1a, 80686 Munich, Germany
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Müller V, Oren A. Metabolism of chloride in halophilic prokaryotes. Extremophiles 2003; 7:261-6. [PMID: 12728360 DOI: 10.1007/s00792-003-0332-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2002] [Accepted: 03/26/2003] [Indexed: 10/26/2022]
Abstract
While much understanding has been achieved on the intracellular sodium and potassium concentrations of halophilic and halotolerant microorganisms and on their regulation, we know little on the metabolism of anions. Archaea of the family Halobacteriaceae contain molar concentrations of chloride, which is pumped into the cells by cotransport with sodium ions and/or using the light-driven primary chloride pump halorhodopsin. Most halophilic and halotolerant representatives of the bacterial domain contain low intracellular ion concentrations, with organic osmotic solutes providing osmotic balance. However, some species show a specific requirement for chloride. In Halobacillus halophilus certain functions, such as growth, endospore germination, motility and flagellar synthesis, and glycine betaine transport are chloride dependent. In this organism the expression of a large number of proteins is chloride regulated. Other moderately halophilic Bacteria such as Halomonas elongata do not show a specific demand for chloride. A very high requirement for chloride was demonstrated in two groups of Bacteria that accumulate inorganic salts intracellularly rather than using organic osmotic solutes: the anaerobic Halanaerobiales and the aerobic extremely halophilic Salinibacter ruber. It is thus becoming increasingly clear that chloride has specific functions in haloadaptation in different groups of halophilic microorganisms.
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Affiliation(s)
- Volker Müller
- Section Microbiology, Department Biology I, LMU München, Maria-Ward-Strasse 1a, 80638 München, Germany.
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