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Somayaji A, Dhanjal CR, Lingamsetty R, Vinayagam R, Selvaraj R, Varadavenkatesan T, Govarthanan M. An insight into the mechanisms of homeostasis in extremophiles. Microbiol Res 2022; 263:127115. [PMID: 35868258 DOI: 10.1016/j.micres.2022.127115] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 01/10/2023]
Abstract
The homeostasis of extremophiles is one that is a diamond hidden in the rough. The way extremophiles adapt to their extreme environments gives a clue into the true extent of what is possible when it comes to life. The discovery of new extremophiles is ever-expanding and an explosion of knowledge surrounding their successful existence in extreme environments is obviously perceived in scientific literature. The present review paper aims to provide a comprehensive view on the different mechanisms governing the extreme adaptations of extremophiles, along with insights and discussions on what the limits of life can possibly be. The membrane adaptations that are vital for survival are discussed in detail. It was found that there are many alterations in the genetic makeup of such extremophiles when compared to their mesophilic counterparts. Apart from the several proteins involved, the significance of chaperones, efflux systems, DNA repair proteins and a host of other enzymes that adapt to maintain functionality, are enlisted, and explained. A deeper understanding of the underlying mechanisms could have a plethora of applications in the industry. There are cases when certain microbes can withstand extreme doses of antibiotics. Such microbes accumulate numerous genetic elements (or plasmids) that possess genes for multiple drug resistance (MDR). A deeper understanding of such mechanisms helps in the development of potential approaches and therapeutic schemes for treating pathogen-mediated outbreaks. An in-depth analysis of the parameters - radiation, pressure, temperature, pH value and metal resistance - are discussed in this review, and the key to survival in these precarious niches is described.
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Affiliation(s)
- Adithi Somayaji
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Chetan Roger Dhanjal
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Rathnamegha Lingamsetty
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Ramesh Vinayagam
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Raja Selvaraj
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Thivaharan Varadavenkatesan
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
| | - Muthusamy Govarthanan
- Department of Environmental Engineering, Kyungpook National University, Daegu, South Korea; Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600077, India.
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Gupta AD, Gupta A, Reyes-Calderón A, Merupo VI, Kalita G, Herrera-Celis J, Chandra N, Sharma A, Ramirez JT, Arriaga LG, Oza G. Biological Synthesis of PbS, As 3S 4, HgS, CdS Nanoparticles using Pseudomonas aeruginosa and their Structural, Morphological, Photoluminescence as well as Whole Cell Protein Profiling Studies. J Fluoresc 2021; 31:1445-1459. [PMID: 34268653 DOI: 10.1007/s10895-021-02769-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/30/2021] [Indexed: 10/20/2022]
Abstract
Metal sulfide nanoparticles are semi-conductors that possess many applications in optics, optoelectronics and magnetic devices. There are physical and chemical methods for their synthesis but such methods involve toxic precursors as well as many obnoxious by-products. Hence, biological synthesis of metal sulfide nanoparticles are efficient enough to transform toxic metals to non-toxic ones. Pseudomonas aeruginosa, isolated from textile effluent and tolerant of high levels of heavy metals, was used for the green synthesis of metal sulfide (HgS, As3S4, CdS and PbS) nanoparticles. The optical, structural and morphological nature of metal sulfide nanoparticles was also determined. FTIR (Fourier Transform Infra-red) analysis showed spectral changes when P. aeruginosa was grown in medium containing heavy metals viz. Hg, As, Pb and Cd indicating that there are functional groups viz. carboxyl, hydroxyl, phosphate, amino and amide, that exists on the surface of the bacteria, thus facilitating binding of metals on its surface. The bacterial samples which were treated with different metals at different concentrations, were subjected to whole cell protein analysis using SDS-PAGE (Sodium dodecyl Sulphate- Polyacrylamide gel electrophoresis) and protein profiling. The total protein estimation revealed that there was an increase in the protein concentration in the presence of heavy metals and a significant change in the banding pattern was observed which showed induction of a set of proteins under heavy metal stress especially mercury.
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Affiliation(s)
- Annika Durve Gupta
- Department of Biotechnology, Birla College of Arts, Science and Commerce, Thane Dist, Kalyan, MS, India.
| | - Arvind Gupta
- Bioxia, H-7 Rajlakshmi complex khaler Bhiwandi Thane, Bhiwandi, India
| | - Almendra Reyes-Calderón
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio González Fracc. San Pablo, No. 500, 76130, Queretaro, Mexico
| | - Victor Ishrayelu Merupo
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Golap Kalita
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Jośe Herrera-Celis
- Laboratorio Nacional de Micro Y Nanofluidica (LABMyN), Centro de Investigación y Desarrollo Tecnológico en Electroquímica (CIDETEQ), Queretaro, 76703, México
| | - Naresh Chandra
- Department of Biotechnology, Birla College of Arts, Science and Commerce, Thane Dist, Kalyan, MS, India
| | - Ashutosh Sharma
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Av. Epigmenio González Fracc. San Pablo, No. 500, 76130, Queretaro, Mexico
| | - Jose Tapia Ramirez
- Department of Genetics and Molecular Biology, Centro de Investigación Y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAVIPN), 0730, Mexico City, Mexico
| | - L G Arriaga
- Laboratorio Nacional de Micro Y Nanofluidica (LABMyN), Centro de Investigación y Desarrollo Tecnológico en Electroquímica (CIDETEQ), Queretaro, 76703, México
| | - Goldie Oza
- Laboratorio Nacional de Micro Y Nanofluidica (LABMyN), Centro de Investigación y Desarrollo Tecnológico en Electroquímica (CIDETEQ), Queretaro, 76703, México.
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Krishna PS, Raghunathan S, Prakash JSS. Comparative genome analysis of Alkalihalobacillus okhensis Kh10-101 T reveals insights into adaptive mechanisms for halo-alkali tolerance. 3 Biotech 2021; 11:392. [PMID: 34350093 DOI: 10.1007/s13205-021-02938-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/22/2021] [Indexed: 11/26/2022] Open
Abstract
Alkalihalobacillus okhensis is a halo-alkaliphile with optimal growth at pH 10 and 5% NaCl. Phylogenetic analysis revealed habitat-dependent segregation of Bacilli, with all the alkalihalophiles forming a separate clade. It uses acidification of the external medium and pH-dependent cell wall reinforcement to survive sodic environments. Interestingly, comparative genome analysis revealed the genome encodes surface proteins with a high proportion of acidic amino acids compared to their orthologs of B. subtilis, a piece of direct evidence for adaptive evolution. It has a relatively higher number of genes involved in the metabolism of osmolytes and sodium-dependent transporters when compared to B. subtilis. Growth of Alkalihalobacillus okhensis strain Kh10-101 T (hereafter A. okhensis) is Na+ dependent, with a minimum of 4% NaCl at neutral pH, but 0.5% NaCl is enough at pH 10. It tolerated a sudden increase in salt concentration and exhibited an elongated phenotype but could not tolerate a sudden pH shift from 7 to 11. The cell envelope got damaged, confirming that the pH regulation through cell wall reinforcement is key to survival at a high-pH condition. We report for the first time a comprehensive genome analysis of Bacilli to delineate the mechanisms evolved for adaptation to halo-alkaline conditions. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02938-x.
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Affiliation(s)
- Pilla Sankara Krishna
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana 500046 India
| | - Sarada Raghunathan
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana 500046 India
| | - Jogadhenu S S Prakash
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana 500046 India
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Challenges and Adaptations of Life in Alkaline Habitats. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:85-133. [DOI: 10.1007/10_2019_97] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Ghosh D, Bhadury P, Routh J. Coping with arsenic stress: Adaptations of arsenite-oxidizing bacterial membrane lipids to increasing arsenic levels. Microbiologyopen 2018; 7:e00594. [PMID: 29577673 PMCID: PMC6182550 DOI: 10.1002/mbo3.594] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 01/01/2018] [Accepted: 01/05/2018] [Indexed: 11/29/2022] Open
Abstract
Elevated levels of arsenic (As) in aquifers of South East Asia have caused diverse health problems affecting millions of people who drink As-rich groundwater and consume various contaminated agriculture products. The biogeochemical cycling and mobilization/immobilization of As from its mineral-bound phase is controlled by pH, oxic/anoxic conditions, and different microbial processes. The increased As flux generated from ongoing biogeochemical processes in the subsurface in turn affects the in situ microbial communities. This study analyzes how the indigenous arsenite-oxidizing bacteria combat As stress by various biophysical alterations and self-adaptation mechanisms. Fifteen arsenite-oxidizing bacterial strains were isolated and identified using a polyphasic approach. The bacterial strains isolated from these aquifers belong predominantly to arsenite-oxidizing bacterial groups. Of these, the membrane-bound phospholipid fatty acids (PLFA) were characterized in seven selected bacterial isolates grown at different concentrations of As(III) in the medium. One of the significant findings of this study is how the increase in external stress can induce alteration of membrane PLFAs. The change in fatty acid saturation and alteration of their steric conformation suggests alteration of membrane fluidity due to change in As-related stress. However, different bacterial groups can have different degrees of alteration that can affect sustainability in As-rich aquifers of the Bengal Delta Plain.
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Affiliation(s)
- Devanita Ghosh
- Integrative Taxonomy and Microbial Ecology Research GroupDepartment of Biological SciencesIndian Institute of Science Education and Research KolkataMohanpurWest BengalIndia
- Department of Thematic StudiesEnvironmental ChangeLinköping UniversityLinköpingSweden
- Present address:
Laboratory of Biogeochem‐mysteryCentre for Earth SciencesIndian Institute of ScienceBangaloreIndia
| | - Punyasloke Bhadury
- Integrative Taxonomy and Microbial Ecology Research GroupDepartment of Biological SciencesIndian Institute of Science Education and Research KolkataMohanpurWest BengalIndia
| | - Joyanto Routh
- Department of Thematic StudiesEnvironmental ChangeLinköping UniversityLinköpingSweden
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Rodríguez MR, Aguirre JS, Lianou A, Parra-Flores J, García de Fernando GD. Analysis of the variability in microbial inactivation by acid treatments. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.10.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gurbanov R, Simsek Ozek N, Gozen AG, Severcan F. Quick Discrimination of Heavy Metal Resistant Bacterial Populations Using Infrared Spectroscopy Coupled with Chemometrics. Anal Chem 2015; 87:9653-61. [DOI: 10.1021/acs.analchem.5b01659] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rafig Gurbanov
- Department of Biochemistry and ‡Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey
| | - Nihal Simsek Ozek
- Department of Biochemistry and ‡Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey
| | - Ayse Gul Gozen
- Department of Biochemistry and ‡Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey
| | - Feride Severcan
- Department of Biochemistry and ‡Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey
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Noor YM, Samsulrizal NH, Jema'on NA, Low KO, Ramli ANM, Alias NI, Damis SIR, Fuzi SFZM, Isa MNM, Murad AMA, Raih MFM, Bakar FDA, Najimudin N, Mahadi NM, Illias RM. A comparative genomic analysis of the alkalitolerant soil bacterium Bacillus lehensis G1. Gene 2014; 545:253-61. [PMID: 24811681 DOI: 10.1016/j.gene.2014.05.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 04/27/2014] [Accepted: 05/03/2014] [Indexed: 10/25/2022]
Abstract
Bacillus lehensis G1 is a Gram-positive, moderately alkalitolerant bacterium isolated from soil samples. B. lehensis produces cyclodextrin glucanotransferase (CGTase), an enzyme that has enabled the extensive use of cyclodextrin in foodstuffs, chemicals, and pharmaceuticals. The genome sequence of B. lehensis G1 consists of a single circular 3.99 Mb chromosome containing 4017 protein-coding sequences (CDSs), of which 2818 (70.15%) have assigned biological roles, 936 (23.30%) have conserved domains with unknown functions, and 263 (6.55%) have no match with any protein database. Bacillus clausii KSM-K16 was established as the closest relative to B. lehensis G1 based on gene content similarity and 16S rRNA phylogenetic analysis. A total of 2820 proteins from B. lehensis G1 were found to have orthologues in B. clausii, including sodium-proton antiporters, transport proteins, and proteins involved in ATP synthesis. A comparative analysis of these proteins and those in B. clausii and other alkaliphilic Bacillus species was carried out to investigate their contributions towards the alkalitolerance of the microorganism. The similarities and differences in alkalitolerance-related genes among alkalitolerant/alkaliphilic Bacillus species highlight the complex mechanism of pH homeostasis. The B. lehensis G1 genome was also mined for proteins and enzymes with potential viability for industrial and commercial purposes.
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Affiliation(s)
- Yusuf Muhammad Noor
- Malaysia Genome Institute, Ministry of Science, Technology and Innovation, Jalan Bangi, 43000 Kajang, Selangor, Malaysia
| | - Nurul Hidayah Samsulrizal
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Noor Azah Jema'on
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Kheng Oon Low
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Aizi Nor Mazila Ramli
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Noor Izawati Alias
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Siti Intan Rosdianah Damis
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Siti Fatimah Zaharah Mohd Fuzi
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Mohd Noor Mat Isa
- Malaysia Genome Institute, Ministry of Science, Technology and Innovation, Jalan Bangi, 43000 Kajang, Selangor, Malaysia
| | - Abdul Munir Abdul Murad
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Mohd Firdaus Mohd Raih
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Farah Diba Abu Bakar
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Nazalan Najimudin
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
| | - Nor Muhammad Mahadi
- Malaysia Genome Institute, Ministry of Science, Technology and Innovation, Jalan Bangi, 43000 Kajang, Selangor, Malaysia
| | - Rosli Md Illias
- Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia.
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Adaptation in Haloalkaliphiles and Natronophilic Bacteria. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2013. [DOI: 10.1007/978-94-007-6488-0_5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Flahaut S, Tierny Y, Watier D, Hornez JP, Jeanfils J. Impact of thermal variations on biochemical and physiological traits in Pectinatus sp. Int J Food Microbiol 2000; 55:53-61. [PMID: 10791717 DOI: 10.1016/s0168-1605(00)00194-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The influence of temperature on cellular fatty acid composition and on heat stress tolerance was studied in the two species of Pectinatus, an anaerobic gram-negative bacterium. Cellular fatty acid (FA) patterns were determined for Pectinatus species cultivated in MRS medium at various defined conditions of temperature and pH. Our study shows that fluctuations of growth temperature and pH induced important changes in the ratio of unsaturated FAs (UFAs) to saturated FAs (SFAs). The major differences in the FA composition as a function of growth temperature concerned C15:0 and C17:0 for the SFAs and C15:1 and C17:1 for the UFAs. The most significant adaptation of lipid composition to lower growth temperatures was the strong increase of UFAs, particularly for C15:1 and C17:1 concomitantly with a decrease of SFAs (C15:0 and C17:0). When the pH of the culture medium was lowered from 6.2 to 4.0, a notable drop in the synthesis of the UFAs C15:1 and C17:1 was observed together with an important increase of C18-cyclopropane (C18-cyc) and high carbon number SFAs. Thermal modifications also provoked changes in Pectinatus behaviour. We observed that P. cerevisiiphilus was more heat sensitive than P. frisingensis. Mild exponential phase cells were treated for 1 h, at 40 degrees C for P. cerevisiiphilus or at 41 degrees C for P. frisingensis. This thermal adaptation induced tolerance against heat challenge (49 and 50 degrees C for P. cerevisiiphilus and P. frisingensis, respectively). Survival of P. cerevisiiphilus and P. frisingensis adapted cells was, respectively, 3400- and 790-fold higher than control. Interestingly, adapted cells of P. cerevisiiphilus were more thermotolerant than P. frisingensis pretreated cells.
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Affiliation(s)
- S Flahaut
- Laboratoire de Biologie Cellulaire et Moléculaire, Université du Littoral, Côte d'Opale, Bassin Napoléon, Boulogne/Mer, France.
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Brown JL, Ross T, McMeekin TA, Nichols PD. Acid habituation of Escherichia coli and the potential role of cyclopropane fatty acids in low pH tolerance. Int J Food Microbiol 1997; 37:163-73. [PMID: 9310851 DOI: 10.1016/s0168-1605(97)00068-8] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A reversible adaptive tolerance to low pH termed 'acid habituation' is demonstrated for five strains of Escherichia coli. Superimposed upon the intrinsic acid tolerance of individual strains, acid habituation significantly enhances the survival of exponential phase cultures exposed to a lethal acid challenge (pH 3.0), and minimises inter-strain variability in acid tolerance. The fatty acid composition of acid habituated, non-habituated, and de-habituated exponential phase cultures is also reported. During acid habituation, monounsaturated fatty acids (16:1 omega 7c and 18:1 omega 7c) present in the phospholipids of E. coli are either converted to their cyclopropane derivatives (cy17:0 and cy19:0), or replaced by saturated fatty acids. The acid tolerance of individual strains of E. coli appears to be correlated with membrane cyclopropane fatty acid content and, thus, it is postulated that increased levels of cyclopropane fatty acids may enhance the survival of microbial cells exposed to low pH. The results presented illustrate the remarkable capacity of E. coli to adapt to environmental challenges, and have significant implications for the survival of spoilage and pathogenic bacteria, and hence for food safety.
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Affiliation(s)
- J L Brown
- Department of Agricultural Science, University of Tasmania, Australia. brown
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12
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Van Walraven HS, Hollander E, Scholts MJ, Kraayenhof R. The H+/ATP ratio of the ATP synthase from the cyanobacterium Synechococcus 6716 varies with growth temperature and light intensity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(96)00137-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hicks DB, Krulwich TA. The respiratory chain of alkaliphilic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1229:303-14. [PMID: 7748882 DOI: 10.1016/0005-2728(95)00024-d] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- D B Hicks
- Department of Biochemistry, Mount Sinai School of Medicine of the City University of New York, NY 10029, USA
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14
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Na+ as coupling ion in energy transduction in extremophilic Bacteria and Archaea. World J Microbiol Biotechnol 1995; 11:58-70. [DOI: 10.1007/bf00339136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Affiliation(s)
- H K Hall
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile 36688, USA
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16
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Sturr MG, Guffanti AA, Krulwich TA. Growth and bioenergetics of alkaliphilic Bacillus firmus OF4 in continuous culture at high pH. J Bacteriol 1994; 176:3111-6. [PMID: 8195065 PMCID: PMC205478 DOI: 10.1128/jb.176.11.3111-3116.1994] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The effect of external pH on growth of alkaliphilic Bacillus firmus OF4 was studied in steady-state, pH-controlled cultures at various pH values. Generation times of 54 and 38 min were observed at external pH values of 7.5 and 10.6, respectively. At more alkaline pH values, generation times increased, reaching 690 min at pH 11.4; this was approximately the upper limit of pH for growth with doubling times below 12 h. Decreasing growth rates above pH 11 correlated with an apparent decrease in the ability to tightly regulate cytoplasmic pH and with the appearance of chains of cells. Whereas the cytoplasmic pH was maintained at pH 8.3 or below up to external pH values of 10.8, there was an increase up to pH 8.9 and 9.6 as the growth pH was increased to 11.2 and 11.4, respectively. Both the transmembrane electrical potential and the phosphorylation potential (delta Gp) generally increased over the total pH range, except for a modest fall-off in the delta Gp at pH 11.4. The capacity for pH homeostasis rather than that for oxidative phosphorylation first appeared to become limiting for growth at the high edge of the pH range. No cytoplasmic or membrane-associated organelles were observed at any growth pH, confirming earlier conclusions that structural sequestration of oxidative phosphorylation was not used to resolve the discordance between the total electrochemical proton gradient (delta p) and the delta Gp as the external pH is raised. Were a strictly bulk chemiosmotic coupling mechanism to account for oxidative phosphorylation over the entire range, the deltaGp/deltap ration (which would equal the H+/ATP ratio) would rise from about 3 at pH 7.5 to 13 at pH 11.2, dropping to 7 at pH 11.4 only because of the rise in cytoplasmic pH relative to other parameters. Moreover, the molar growth yields on malate were higher at pH 10.5 than at pH 7.5, indicating greater rather than lesser efficiency in the use of substrate at the more alkaline pH.
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Affiliation(s)
- M G Sturr
- Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029
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Krulwich TA, Guffanti AA. Proton-coupled bioenergetic processes in extremely alkaliphilic bacteria. J Bioenerg Biomembr 1992; 24:587-99. [PMID: 1334072 DOI: 10.1007/bf00762351] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Oxidative phosphorylation, which involves an exclusively proton-coupled ATP synthase, and pH homeostasis, which depends upon electrogenic antiport of cytoplasmic Na+ in exchange for H+, are the two known bioenergetic processes that require inward proton translocation in extremely alkaliphilic bacteria. Energy coupling to oxidative phosphorylation is particularly difficult to fit to a strictly chemiosmotic model because of the low bulk electrochemical proton gradient that follows from the maintenance of a cytoplasmic pH just above 8 during growth at pH 10.5 and higher. A large quantitative and variable discrepancy between the putative chemiosmotic driving force and the phosphorylation potential results. This is compounded by a nonequivalence between respiration-dependent bulk gradients and artificially imposed ones in energizing ATP synthesis, and by an apparent requirement for specific respiratory chain complexes that do not relate solely to their role in generation of bulk gradients. Special features of the synthase may contribute to the mode of energization, just as novel features of the Na+ cycle may relate to the extraordinary capacity of the extreme alkaliphiles to achieve pH homeostasis during growth at, or sudden shifts to, an external pH of 10.5 and above.
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Affiliation(s)
- T A Krulwich
- Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029
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18
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Dunkley EA, Clejan S, Krulwich TA. Mutants of Bacillus species isolated on the basis of protonophore resistance are deficient in fatty acid desaturase activity. J Bacteriol 1991; 173:7750-5. [PMID: 1660453 PMCID: PMC212564 DOI: 10.1128/jb.173.24.7750-7755.1991] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The fatty acid desaturase activity in cell extracts of Bacillus subtilis was characterized and found to be O2 dependent, NADH dependent, and cyanide sensitive. In cell fractionation studies, only 10% of the desaturase activity was recovered in the membrane fraction; the addition of cytosolic factors, which by themselves were devoid of activity, restored membrane activity to the level found in the unfractionated cell extracts. NADH was preferred over NADPH as an electron donor, and palmitoyl-coenzyme A was used preferentially over stearoyl-coenzyme A as the straight-chain fatty acid substrate. An increase in desaturase activity was observed when either the growth or the assay temperature was lowered from 37 to 20 degrees C, although the assay temperature appeared to be the more important parameter. Three protonophore-resistant mutants of B. subtilis and a comparable mutant of Bacillus megaterium had been found to possess reduced levels of unsaturated fatty acids in their membrane phospholipids; their protonophore resistance was abolished when grown in the presence of an unsaturated fatty acid supplement. All of these strains were found to be either significantly deficient in or totally lacking desaturase activity in comparison with their wild-type parent strains. Full, protonophore-sensitive revertants of the mutants had levels of desaturase activity comparable to those of the wild-type. Temperature-sensitive revertants of two of the mutants, which grew at 32 degrees C but not at 26 degrees C in the presence of protonophore, exhibited desaturase activity comparable to that of the wild-type at 26 degrees C but lacked activity at 32 degrees C. These results indicate that the biochemical basis for protonophore resistance in these Bacillus mutants is a fatty acid desaturase deficiency.
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Affiliation(s)
- E A Dunkley
- Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029
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