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Novak JK, Gardner JG. Current models in bacterial hemicellulase-encoding gene regulation. Appl Microbiol Biotechnol 2024; 108:39. [PMID: 38175245 PMCID: PMC10766802 DOI: 10.1007/s00253-023-12977-4] [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: 12/06/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The discovery and characterization of bacterial carbohydrate-active enzymes is a fundamental component of biotechnology innovation, particularly for renewable fuels and chemicals; however, these studies have increasingly transitioned to exploring the complex regulation required for recalcitrant polysaccharide utilization. This pivot is largely due to the current need to engineer and optimize enzymes for maximal degradation in industrial or biomedical applications. Given the structural simplicity of a single cellulose polymer, and the relatively few enzyme classes required for complete bioconversion, the regulation of cellulases in bacteria has been thoroughly discussed in the literature. However, the diversity of hemicelluloses found in plant biomass and the multitude of carbohydrate-active enzymes required for their deconstruction has resulted in a less comprehensive understanding of bacterial hemicellulase-encoding gene regulation. Here we review the mechanisms of this process and common themes found in the transcriptomic response during plant biomass utilization. By comparing regulatory systems from both Gram-negative and Gram-positive bacteria, as well as drawing parallels to cellulase regulation, our goals are to highlight the shared and distinct features of bacterial hemicellulase-encoding gene regulation and provide a set of guiding questions to improve our understanding of bacterial lignocellulose utilization. KEY POINTS: • Canonical regulatory mechanisms for bacterial hemicellulase-encoding gene expression include hybrid two-component systems (HTCS), extracytoplasmic function (ECF)-σ/anti-σ systems, and carbon catabolite repression (CCR). • Current transcriptomic approaches are increasingly being used to identify hemicellulase-encoding gene regulatory patterns coupled with computational predictions for transcriptional regulators. • Future work should emphasize genetic approaches to improve systems biology tools available for model bacterial systems and emerging microbes with biotechnology potential. Specifically, optimization of Gram-positive systems will require integration of degradative and fermentative capabilities, while optimization of Gram-negative systems will require bolstering the potency of lignocellulolytic capabilities.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
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2
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Goldman AL, Fulk EM, Momper LM, Heider C, Mulligan J, Osburn M, Masiello CA, Silberg JJ. Microbial sensor variation across biogeochemical conditions in the terrestrial deep subsurface. mSystems 2024; 9:e0096623. [PMID: 38059636 PMCID: PMC10805038 DOI: 10.1128/msystems.00966-23] [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: 09/15/2023] [Accepted: 11/08/2023] [Indexed: 12/08/2023] Open
Abstract
Microbes can be found in abundance many kilometers underground. While microbial metabolic capabilities have been examined across different geochemical settings, it remains unclear how changes in subsurface niches affect microbial needs to sense and respond to their environment. To address this question, we examined how microbial extracellular sensor systems vary with environmental conditions across metagenomes at different Deep Mine Microbial Observatory (DeMMO) subsurface sites. Because two-component systems (TCSs) directly sense extracellular conditions and convert this information into intracellular biochemical responses, we expected that this sensor family would vary across isolated oligotrophic subterranean environments that differ in abiotic and biotic conditions. TCSs were found at all six subsurface sites, the service water control, and the surface site, with an average of 0.88 sensor histidine kinases (HKs) per 100 genes across all sites. Abundance was greater in subsurface fracture fluids compared with surface-derived fluids, and candidate phyla radiation (CPR) bacteria presented the lowest HK frequencies. Measures of microbial diversity, such as the Shannon diversity index, revealed that HK abundance is inversely correlated with microbial diversity (r2 = 0.81). Among the geochemical parameters measured, HK frequency correlated most strongly with variance in dissolved organic carbon (r2 = 0.82). Taken together, these results implicate the abiotic and biotic properties of an ecological niche as drivers of sensor needs, and they suggest that microbes in environments with large fluctuations in organic nutrients (e.g., lacustrine, terrestrial, and coastal ecosystems) may require greater TCS diversity than ecosystems with low nutrients (e.g., open ocean).IMPORTANCEThe ability to detect extracellular environmental conditions is a fundamental property of all life forms. Because microbial two-component sensor systems convert information about extracellular conditions into biochemical information that controls their behaviors, we evaluated how two-component sensor systems evolved within the deep Earth across multiple sites where abiotic and biotic properties vary. We show that these sensor systems remain abundant in microbial consortia at all subterranean sampling sites and observe correlations between sensor system abundances and abiotic (dissolved organic carbon variation) and biotic (consortia diversity) properties. These results suggest that multiple environmental properties may drive sensor protein evolution and highlight the need for further studies of metagenomic and geochemical data in parallel to understand the drivers of microbial sensor evolution.
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Affiliation(s)
| | - Emily M. Fulk
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, Texas, USA
| | - Lily M. Momper
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - Clinton Heider
- Rice University, Center for Research Computing, Houston, Texas, USA
| | - John Mulligan
- Rice University, Center for Research Computing, Houston, Texas, USA
| | - Magdalena Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - Caroline A. Masiello
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, Texas, USA
- Department of Chemistry, Rice University, Houston, Texas, USA
| | - Jonathan J. Silberg
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, USA
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3
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Leite JP, Lourenço F, Oliveira R, Sousa SF, Mendes MV, Gales L. Crystal structures of Streptomyces tsukubaensis sigma factor SigG1 and anti-sigma RsfG. J Struct Biol 2023; 215:108038. [PMID: 37858875 DOI: 10.1016/j.jsb.2023.108038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/25/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
Transcription of specific genes in bacteria under environmental stress is frequently initiated by extracytoplasmic function (ECF) σ factors. ECFs σ factors harbour two conserved domains, σ2 and σ4, for transcription initiation by recognition of the promoter region and recruitment of RNA polymerase (RNAP). The crystal structure of Streptomyces tsukubaensis SigG1, an ECF56-family σ factor, was determined revealing σ2, σ4 and the additional carboxi-terminal domain SnoaL_2 tightly packed in a compact conformation. The structure of anti-sigma RsfG was also determined by X-ray crystallography and shows a rare β-barrel fold. Analysis of the metal binding motifs inside the protein barrel are consistent with Fe(III) binding, which is in agreement with previous findings that the Streptomyces tsukubaensis ECF56 SigG1-RsfG system is involved in metal-ion homeostasis.
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Affiliation(s)
- José P Leite
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge de Viterbo Ferreira 228, Porto, Porto 4050-313, Portugal
| | - Frederico Lourenço
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal
| | - Rute Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge de Viterbo Ferreira 228, Porto, Porto 4050-313, Portugal
| | - Sérgio F Sousa
- UCIBIO/REQUIMTE, BioSIM, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, Porto 4200-319, Portugal
| | - Marta V Mendes
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal
| | - Luís Gales
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, Porto, Porto 4200-135, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge de Viterbo Ferreira 228, Porto, Porto 4050-313, Portugal.
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Mascher T. Past, Present, and Future of Extracytoplasmic Function σ Factors: Distribution and Regulatory Diversity of the Third Pillar of Bacterial Signal Transduction. Annu Rev Microbiol 2023; 77:625-644. [PMID: 37437215 DOI: 10.1146/annurev-micro-032221-024032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Responding to environmental cues is a prerequisite for survival in the microbial world. Extracytoplasmic function σ factors (ECFs) represent the third most abundant and by far the most diverse type of bacterial signal transduction. While archetypal ECFs are controlled by cognate anti-σ factors, comprehensive comparative genomics efforts have revealed a much higher abundance and regulatory diversity of ECF regulation than previously appreciated. They have also uncovered a diverse range of anti-σ factor-independent modes of controlling ECF activity, including fused regulatory domains and phosphorylation-dependent mechanisms. While our understanding of ECF diversity is comprehensive for well-represented and heavily studied bacterial phyla-such as Proteobacteria, Firmicutes, and Actinobacteria (phylum Actinomycetota)-our current knowledge about ECF-dependent signaling in the vast majority of underrepresented phyla is still far from complete. In particular, the dramatic extension of bacterial diversity in the course of metagenomic studies represents both a new challenge and an opportunity in expanding the world of ECF-dependent signal transduction.
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Affiliation(s)
- Thorsten Mascher
- General Microbiology, Technische Universität Dresden, Dresden, Germany;
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Sensing Host Health: Insights from Sensory Protein Signature of the Metagenome. Appl Environ Microbiol 2022; 88:e0059622. [PMID: 35862686 PMCID: PMC9361814 DOI: 10.1128/aem.00596-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The human microbiota, which comprises an ensemble of taxonomically and functionally diverse but often mutually cooperating microorganisms, benefits its host by shaping the host immunity, energy harvesting, and digestion of complex carbohydrates as well as production of essential nutrients. Dysbiosis in the human microbiota, especially the gut microbiota, has been reported to be linked to several diseases and metabolic disorders. Recent studies have further indicated that tracking these dysbiotic variations could potentially be exploited as biomarkers of disease states. However, the human microbiota is not geography agnostic, and hence a taxonomy-based (microbiome) biomarker for disease diagnostics has certain limitations. In comparison, (microbiome) function-based biomarkers are expected to have a wider applicability. Given that (i) the host physiology undergoes certain changes in the course of a disease and (ii) host-associated microbial communities need to adapt to this changing microenvironment of their host, we hypothesized that signatures emanating from the abundance of bacterial proteins associated with the signal transduction system (herein referred to as sensory proteins [SPs]) might be able to distinguish between healthy and diseased states. To test this hypothesis, publicly available metagenomic data sets corresponding to three diverse health conditions, namely, colorectal cancer, type 2 diabetes mellitus, and schizophrenia, were analyzed. Results demonstrated that SP signatures (derived from host-associated metagenomic samples) indeed differentiated among healthy individual and patients suffering from diseases of various severities. Our finding was suggestive of the prospect of using SP signatures as early biomarkers for diagnosing the onset and progression of multiple diseases and metabolic disorders. IMPORTANCE The composition of the human microbiota, a collection of host-associated microbes, has been shown to differ among healthy and diseased individuals. Recent studies have investigated whether tracking these variations could be exploited for disease diagnostics. It has been noted that compared to microbial taxonomies, the ensemble of functional proteins encoded by microbial genes are less likely to be affected by changes in ethnicity and dietary preferences. These functions are expected to help the microbe adapt to changing environmental conditions. Thus, healthy individuals might harbor a different set of genes than diseased individuals. To test this hypothesis, we analyzed metagenomes from healthy and diseased individuals for signatures of a particular group of proteins called sensory proteins (SP), which enable the bacteria to sense and react to changes in their microenvironment. Results demonstrated that SP signatures indeed differentiate among healthy individuals and those suffering from diseases of various severities.
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Marcos-Torres FJ, Moraleda-Muñoz A, Contreras-Moreno FJ, Muñoz-Dorado J, Pérez J. Mechanisms of Action of Non-Canonical ECF Sigma Factors. Int J Mol Sci 2022; 23:ijms23073601. [PMID: 35408957 PMCID: PMC8999054 DOI: 10.3390/ijms23073601] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Extracytoplasmic function (ECF) sigma factors are subunits of the RNA polymerase specialized in activating the transcription of a subset of genes responding to a specific environmental condition. The signal-transduction pathways where they participate can be activated by diverse mechanisms. The most common mechanism involves the action of a membrane-bound anti-sigma factor, which sequesters the ECF sigma factor, and releases it after the stimulus is sensed. However, despite most of these systems following this canonical regulation, there are many ECF sigma factors exhibiting a non-canonical regulatory mechanism. In this review, we aim to provide an updated and comprehensive view of the different activation mechanisms known for non-canonical ECF sigma factors, detailing their inclusion to the different phylogenetic groups and describing the mechanisms of regulation of some of their representative members such as EcfG from Rhodobacter sphaeroides, showing a partner-switch mechanism; EcfP from Vibrio parahaemolyticus, with a phosphorylation-dependent mechanism; or CorE from Myxococcus xanthus, regulated by a metal-sensing C-terminal extension.
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Affiliation(s)
| | - Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
- Correspondence: (A.M.-M.); (J.P.); Tel.: +34-95-824-2858 (A.M.-M.); +34-95-824-9830 (J.P.)
| | - Francisco Javier Contreras-Moreno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
| | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda, Fuentenueva s/n, 18071 Granada, Spain; (F.J.C.-M.); (J.M.-D.)
- Correspondence: (A.M.-M.); (J.P.); Tel.: +34-95-824-2858 (A.M.-M.); +34-95-824-9830 (J.P.)
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7
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Zannier F, Portero LR, Douki T, Gärtner W, Farías ME, Albarracín VH. Proteomic Signatures of Microbial Adaptation to the Highest Ultraviolet-Irradiation on Earth: Lessons From a Soil Actinobacterium. Front Microbiol 2022; 13:791714. [PMID: 35369494 PMCID: PMC8965627 DOI: 10.3389/fmicb.2022.791714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/26/2022] [Indexed: 11/13/2022] Open
Abstract
In the Central Andean region in South America, high-altitude ecosystems (3500-6000 masl) are distributed across Argentina, Chile, Bolivia, and Peru, in which poly-extremophilic microbes thrive under extreme environmental conditions. In particular, in the Puna region, total solar irradiation and UV incidence are the highest on Earth, thus, restraining the physiology of individual microorganisms and the composition of microbial communities. UV-resistance of microbial strains thriving in High-Altitude Andean Lakes was demonstrated and their mechanisms were partially characterized by genomic analysis, biochemical and physiological assays. Then, the existence of a network of physiological and molecular mechanisms triggered by ultraviolet light exposure was hypothesized and called "UV-resistome". It includes some or all of the following subsystems: (i) UV sensing and effective response regulators, (ii) UV-avoidance and shielding strategies, (iii) damage tolerance and oxidative stress response, (iv) energy management and metabolic resetting, and (v) DNA damage repair. Genes involved in the described UV-resistome were recently described in the genome of Nesterenkonia sp. Act20, an actinobacterium which showed survival to high UV-B doses as well as efficient photorepairing capability. The aim of this work was to use a proteomic approach together with photoproduct measurements to help dissecting the molecular events involved in the adaptive response of a model High-Altitude Andean Lakes (HAAL) extremophilic actinobacterium, Nesterenkonia sp. Act20, under artificial UV-B radiation. Our results demonstrate that UV-B exposure induced over-abundance of a well-defined set of proteins while recovery treatments restored the proteomic profiles present before the UV-challenge. The proteins involved in this complex molecular network were categorized within the UV-resistome subsystems: damage tolerance and oxidative stress response, energy management and metabolic resetting, and DNA damage repair.
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Affiliation(s)
- Federico Zannier
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica, Facultad de Agronomía y Zootecnia, UNT y Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas, Planta Piloto de Procesos Industriales y Microbiológicos, Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
| | - Luciano R. Portero
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica, Facultad de Agronomía y Zootecnia, UNT y Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas, Planta Piloto de Procesos Industriales y Microbiológicos, Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
| | - Thierry Douki
- Université Grenoble Alpes, Commissariat a l’Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Institut de Recherche Interdisciplinaire de Grenoble–Systèmes Moléculaires et nanoMatériaux p our l’Énergie et la Santé, Grenoble, France
| | - Wolfgang Gärtner
- Institute of Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - María E. Farías
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica, Facultad de Agronomía y Zootecnia, UNT y Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
| | - Virginia H. Albarracín
- Laboratorio de Microbiología Ultraestructural y Molecular, Centro Integral de Microscopía Electrónica, Facultad de Agronomía y Zootecnia, UNT y Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas, Planta Piloto de Procesos Industriales y Microbiológicos, Centro Científico Tecnológico, CONICET NOASUR, San Miguel de Tucumán, Argentina
- Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina
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8
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de Dios R, Santero E, Reyes-Ramírez F. Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses. Int J Mol Sci 2021; 22:ijms22083900. [PMID: 33918849 PMCID: PMC8103513 DOI: 10.3390/ijms22083900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 01/03/2023] Open
Abstract
The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.
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9
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Casas-Pastor D, Müller RR, Jaenicke S, Brinkrolf K, Becker A, Buttner MJ, Gross CA, Mascher T, Goesmann A, Fritz G. Expansion and re-classification of the extracytoplasmic function (ECF) σ factor family. Nucleic Acids Res 2021; 49:986-1005. [PMID: 33398323 PMCID: PMC7826278 DOI: 10.1093/nar/gkaa1229] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/01/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022] Open
Abstract
Extracytoplasmic function σ factors (ECFs) represent one of the major bacterial signal transduction mechanisms in terms of abundance, diversity and importance, particularly in mediating stress responses. Here, we performed a comprehensive phylogenetic analysis of this protein family by scrutinizing all proteins in the NCBI database. As a result, we identified an average of ∼10 ECFs per bacterial genome and 157 phylogenetic ECF groups that feature a conserved genetic neighborhood and a similar regulation mechanism. Our analysis expands previous classification efforts ∼50-fold, enriches many original ECF groups with previously unclassified proteins and identifies 22 entirely new ECF groups. The ECF groups are hierarchically related to each other and are further composed of subgroups with closely related sequences. This two-tiered classification allows for the accurate prediction of common promoter motifs and the inference of putative regulatory mechanisms across subgroups composing an ECF group. This comprehensive, high-resolution description of the phylogenetic distribution of the ECF family, together with the massive expansion of classified ECF sequences and an openly accessible data repository called ‘ECF Hub’ (https://www.computational.bio.uni-giessen.de/ecfhub), will serve as a powerful hypothesis-generator to guide future research in the field.
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Affiliation(s)
- Delia Casas-Pastor
- Center for Synthetic Microbiology (SYNMIKRO), Philipps Universität Marburg, Germany
| | - Raphael R Müller
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, Giessen, Germany
| | - Sebastian Jaenicke
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, Giessen, Germany
| | - Karina Brinkrolf
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, Giessen, Germany
| | - Anke Becker
- Center for Synthetic Microbiology (SYNMIKRO), Philipps Universität Marburg, Germany
| | - Mark J Buttner
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität Dresden, Germany
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, Giessen, Germany
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
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10
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Oliveira R, Bush MJ, Pires S, Chandra G, Casas-Pastor D, Fritz G, Mendes MV. The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis. Sci Rep 2020; 10:21728. [PMID: 33303917 PMCID: PMC7730460 DOI: 10.1038/s41598-020-78520-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022] Open
Abstract
Extracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2-σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.
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Affiliation(s)
- Rute Oliveira
- Bioengineering and Synthetic Microbiology Group, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCBiology), ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Sílvia Pires
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Jill Roberts Institute for IBD Research, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Delia Casas-Pastor
- Center for Synthetic Microbiology, Philipps-University Marburg, 35032, Marburg, Germany
| | - Georg Fritz
- School for Molecular Sciences, University of Western Australia, Perth, 6009, Australia
| | - Marta V Mendes
- Bioengineering and Synthetic Microbiology Group, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
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11
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Casas-Pastor D, Diehl A, Fritz G. Coevolutionary Analysis Reveals a Conserved Dual Binding Interface between Extracytoplasmic Function σ Factors and Class I Anti-σ Factors. mSystems 2020; 5:e00310-20. [PMID: 32753504 PMCID: PMC7406223 DOI: 10.1128/msystems.00310-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/17/2020] [Indexed: 11/30/2022] Open
Abstract
Extracytoplasmic function σ factors (ECFs) belong to the most abundant signal transduction mechanisms in bacteria. Among the diverse regulators of ECF activity, class I anti-σ factors are the most important signal transducers in response to internal and external stress conditions. Despite the conserved secondary structure of the class I anti-σ factor domain (ASDI) that binds and inhibits the ECF under noninducing conditions, the binding interface between ECFs and ASDIs is surprisingly variable between the published cocrystal structures. In this work, we provide a comprehensive computational analysis of the ASDI protein family and study the different contact themes between ECFs and ASDIs. To this end, we harness the coevolution of these diverse protein families and predict covarying amino acid residues as likely candidates of an interaction interface. As a result, we find two common binding interfaces linking the first alpha-helix of the ASDI to the DNA-binding region in the σ4 domain of the ECF, and the fourth alpha-helix of the ASDI to the RNA polymerase (RNAP)-binding region of the σ2 domain. The conservation of these two binding interfaces contrasts with the apparent quaternary structure diversity of the ECF/ASDI complexes, partially explaining the high specificity between cognate ECF and ASDI pairs. Furthermore, we suggest that the dual inhibition of RNAP- and DNA-binding interfaces is likely a universal feature of other ECF anti-σ factors, preventing the formation of nonfunctional trimeric complexes between σ/anti-σ factors and RNAP or DNA.IMPORTANCE In the bacterial world, extracytoplasmic function σ factors (ECFs) are the most widespread family of alternative σ factors, mediating many cellular responses to environmental cues, such as stress. This work uses a computational approach to investigate how these σ factors interact with class I anti-σ factors-the most abundant regulators of ECF activity. By comprehensively classifying the anti-σs into phylogenetic groups and by comparing this phylogeny to the one of the cognate ECFs, the study shows how these protein families have coevolved to maintain their interaction over evolutionary time. These results shed light on the common contact residues that link ECFs and anti-σs in different phylogenetic families and set the basis for the rational design of anti-σs to specifically target certain ECFs. This will help to prevent the cross talk between heterologous ECF/anti-σ pairs, allowing their use as orthogonal regulators for the construction of genetic circuits in synthetic biology.
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Affiliation(s)
- Delia Casas-Pastor
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Angelika Diehl
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
- School of Molecular Sciences, University of Western Australia, Perth, Australia
| | - Georg Fritz
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
- School of Molecular Sciences, University of Western Australia, Perth, Australia
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12
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Can Pathogenic and Nonpathogenic Bacteria Be Distinguished by Sensory Protein Abundance? Appl Environ Microbiol 2020; 86:AEM.00478-20. [PMID: 32385079 DOI: 10.1128/aem.00478-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/29/2020] [Indexed: 01/19/2023] Open
Abstract
Signal transduction systems are essential for microorganisms to respond to their ever-changing environment. They can be distinguished into one-component systems, two-component systems, and extracytoplasmic-function σ factors. Abundances of a few signal-transducing proteins, termed herein as sensory proteins (SPs), have previously been reported to be correlated with the genome size and ecological niche of certain Gram-positive bacteria. No such reports are available for Gram-negative bacteria. The current study attempts to investigate the relationship of the abundances of SPs to genome size in Escherichia coli, and the bacterial pathotypes or phylotypes. While the relationship between SP abundance and genome size could not be established, the sensory protein index (SPI), a new metric defined herein, was found to be correlated with E. coli virulence. In addition, significant association was observed among the distribution of SPs and E. coli pathotypes. Results indicate that such associations might be due to genomic rearrangements to best utilize the resources available in a given ecological niche. Overall, the study provides an in-depth analysis of the occurrence of different SPs among pathogenic and nonpathogenic E. coli strains. Possibilities of using the SPI as a marker for identifying pathogenic strains from among an organism complex are also discussed.IMPORTANCE Sensory proteins (SPs) act as sensors and actuators for a cell and participate in important mechanisms pertaining to bacterial survival, adaptation, and virulence. Therefore, bacterial species residing in similar ecological niches or those sharing common pathotypes are expected to exhibit similar SP signatures. We have investigated profiles of SPs in different species of Escherichia coli and present in this article the sensory protein index (SPI), a metric for quantifying the abundance and/or distribution of SPs across bacterial genomes, which could indicate the virulence potency of a bacterium. The SPI could find use in characterizing uncultured strains and bacterial complexes, as a biomarker for disease diagnostics, evaluating the effect of therapeutic interventions, assessing effects of ecological alterations, etc. Grouping the studied strains of E. coli on the basis of the frequency of occurrence of SPs in their genomes could potentially replicate the stratification of these strains on the basis of their phylotypes. In addition, E. coli strains belonging to the same pathotypes were also seen to share similar SP signatures. Furthermore, the SPI was seen to be an indicator of pathogenic potency of E. coli strains. The SPI metric is expected to be useful in the (pathogenic) characterization of hereto uncultured strains which are routinely sequenced in host microbiome analysis projects, or from among an ensemble of microbial organisms constituting a biospecimen. Thus, the possibilities of using the SPI as a biomarker for diagnosis of a disease or the outcome of a therapeutic intervention cannot be ruled out. Further, SPIs obtained from longitudinal ecological samples have the potential to serve as key indicators of environmental changes. Such changes in the environment are often detrimental to the resident biome and methods for timely detection of environmental changes hold huge socioeconomic benefits.
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13
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Maghembe R, Damian D, Makaranga A, Nyandoro SS, Lyantagaye SL, Kusari S, Hatti-Kaul R. Omics for Bioprospecting and Drug Discovery from Bacteria and Microalgae. Antibiotics (Basel) 2020; 9:antibiotics9050229. [PMID: 32375367 PMCID: PMC7277505 DOI: 10.3390/antibiotics9050229] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/10/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
"Omics" represent a combinatorial approach to high-throughput analysis of biological entities for various purposes. It broadly encompasses genomics, transcriptomics, proteomics, lipidomics, and metabolomics. Bacteria and microalgae exhibit a wide range of genetic, biochemical and concomitantly, physiological variations owing to their exposure to biotic and abiotic dynamics in their ecosystem conditions. Consequently, optimal conditions for adequate growth and production of useful bacterial or microalgal metabolites are critically unpredictable. Traditional methods employ microbe isolation and 'blind'-culture optimization with numerous chemical analyses making the bioprospecting process laborious, strenuous, and costly. Advances in the next generation sequencing (NGS) technologies have offered a platform for the pan-genomic analysis of microbes from community and strain downstream to the gene level. Changing conditions in nature or laboratory accompany epigenetic modulation, variation in gene expression, and subsequent biochemical profiles defining an organism's inherent metabolic repertoire. Proteome and metabolome analysis could further our understanding of the molecular and biochemical attributes of the microbes under research. This review provides an overview of recent studies that have employed omics as a robust, broad-spectrum approach for screening bacteria and microalgae to exploit their potential as sources of drug leads by focusing on their genomes, secondary metabolite biosynthetic pathway genes, transcriptomes, and metabolomes. We also highlight how recent studies have combined molecular biology with analytical chemistry methods, which further underscore the need for advances in bioinformatics and chemoinformatics as vital instruments in the discovery of novel bacterial and microalgal strains as well as new drug leads.
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Affiliation(s)
- Reuben Maghembe
- Department of Molecular Biology and Biotechnology, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 25179, Dar es Salaam, Tanzania; (R.M.); (D.D.); (S.L.L.)
- Department of Biological and Marine Sciences, Marian University College, P.O. Box 47, Bagamoyo, Tanzania;
- Division of Biotechnology, Department of Chemistry, Center for Chemistry and Chemical Engineering, Lund University, Box 124, 22100 Lund, Sweden
| | - Donath Damian
- Department of Molecular Biology and Biotechnology, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 25179, Dar es Salaam, Tanzania; (R.M.); (D.D.); (S.L.L.)
| | - Abdalah Makaranga
- Department of Biological and Marine Sciences, Marian University College, P.O. Box 47, Bagamoyo, Tanzania;
- International Center for Genetic Engineering and Biotechnology (ICGEB), Omics of Algae Group, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Stephen Samwel Nyandoro
- Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania;
| | - Sylvester Leonard Lyantagaye
- Department of Molecular Biology and Biotechnology, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 25179, Dar es Salaam, Tanzania; (R.M.); (D.D.); (S.L.L.)
- Department of Biochemistry, Mbeya College of Health and Allied Sciences, University of Dar es Salaam, P.O. Box 608, Mbeya, Tanzania
| | - Souvik Kusari
- Institute of Environmental Research (INFU), Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44221 Dortmund, Germany
- Correspondence: (S.K.); (R.H.-K.); Tel.: +49-2317554086 (S.K.); +46-462224840 (R.H.-K.)
| | - Rajni Hatti-Kaul
- Division of Biotechnology, Department of Chemistry, Center for Chemistry and Chemical Engineering, Lund University, Box 124, 22100 Lund, Sweden
- Correspondence: (S.K.); (R.H.-K.); Tel.: +49-2317554086 (S.K.); +46-462224840 (R.H.-K.)
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14
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Iyer SC, Casas-Pastor D, Kraus D, Mann P, Schirner K, Glatter T, Fritz G, Ringgaard S. Transcriptional regulation by σ factor phosphorylation in bacteria. Nat Microbiol 2020; 5:395-406. [PMID: 31988380 DOI: 10.1038/s41564-019-0648-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/27/2019] [Indexed: 11/09/2022]
Abstract
A major form of transcriptional regulation in bacteria occurs through the exchange of the primary σ factor of RNA polymerase (RNAP) with an alternative extracytoplasmic function (ECF) σ factor1. ECF σ factors are generally intrinsically active and are retained in an inactive state via the sequestration into σ factor-anti-σ factor complexes until their action is warranted2-20. Here, we report a previously uncharacterized mechanism of transcriptional regulation that relies on intrinsically inactive ECF σ factors, the activation of which and interaction with the β'-subunit of RNAP depends on σ factor phosphorylation. In Vibrio parahaemolyticus, the threonine kinase PknT phosphorylates the σ factor EcfP, which results in EcfP activation and expression of an essential polymyxin-resistant regulon. EcfP phosphorylation occurs at a highly conserved threonine residue, Thr63, positioned within a divergent region in the σ2.2 helix. Our data indicate that EcfP is intrinsically inactive and unable to bind the β'-subunit of RNAP due to the absence of a negatively charged DAED motif in this region. Furthermore, our results indicate that phosphorylation at residue Thr63 mimics this negative charge and licenses EcfP to interact with the β'-subunit in the formation of the RNAP holoenzyme, which in turn results in target gene expression. This regulatory mechanism is a previously unrecognized paradigm in bacterial signal transduction and transcriptional regulation, and our data suggest that it is widespread in bacteria.
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Affiliation(s)
| | | | - David Kraus
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Petra Mann
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Timo Glatter
- Core Facility for Mass Spectrometry and Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Georg Fritz
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Simon Ringgaard
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
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15
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Pinto D, da Fonseca RR. Evolution of the extracytoplasmic function σ factor protein family. NAR Genom Bioinform 2020; 2:lqz026. [PMID: 33575573 PMCID: PMC7671368 DOI: 10.1093/nargab/lqz026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/04/2019] [Accepted: 12/19/2019] [Indexed: 12/18/2022] Open
Abstract
Understanding transcription has been a central goal of the scientific community for decades. However, much is still unknown, especially concerning how it is regulated. In bacteria, a single DNA-directed RNA-polymerase performs the whole of transcription. It contains multiple subunits, among which the σ factor that confers promoter specificity. Besides the housekeeping σ factor, bacteria encode several alternative σ factors. The most abundant and diverse family of alternative σ factors, the extracytoplasmic function (ECF) family, regulates transcription of genes associated with stressful scenarios, making them key elements of adaptation to specific environmental changes. Despite this, the evolutionary history of ECF σ factors has never been investigated. Here, we report on our analysis of thousands of members of this family. We show that single events are in the origin of alternative modes of regulation of ECF σ factor activity that require partner proteins, but that multiple events resulted in acquisition of regulatory extensions. Moreover, in Bacteroidetes there is a recent duplication of an ecologically relevant gene cluster that includes an ECF σ factor, whereas in Planctomycetes duplication generates distinct C-terminal extensions after fortuitous insertion of the duplicated σ factor. At last, we also demonstrate horizontal transfer of ECF σ factors between soil bacteria.
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Affiliation(s)
- Daniela Pinto
- Technische Universität Dresden, Institute of Microbiology, Zellescher Weg 20b, 01217 Dresden, Germany
| | - Rute R da Fonseca
- Center for Macroecology, Evolution and Climate (CMEC), GLOBE Institute, University of Copenhagen, 1350 Copenhagen K, Denmark
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16
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Wiegand S, Jogler M, Boedeker C, Pinto D, Vollmers J, Rivas-Marín E, Kohn T, Peeters SH, Heuer A, Rast P, Oberbeckmann S, Bunk B, Jeske O, Meyerdierks A, Storesund JE, Kallscheuer N, Lücker S, Lage OM, Pohl T, Merkel BJ, Hornburger P, Müller RW, Brümmer F, Labrenz M, Spormann AM, Op den Camp HJM, Overmann J, Amann R, Jetten MSM, Mascher T, Medema MH, Devos DP, Kaster AK, Øvreås L, Rohde M, Galperin MY, Jogler C. Cultivation and functional characterization of 79 planctomycetes uncovers their unique biology. Nat Microbiol 2019; 5:126-140. [PMID: 31740763 DOI: 10.1038/s41564-019-0588-1] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 09/12/2019] [Indexed: 01/01/2023]
Abstract
When it comes to the discovery and analysis of yet uncharted bacterial traits, pure cultures are essential as only these allow detailed morphological and physiological characterization as well as genetic manipulation. However, microbiologists are struggling to isolate and maintain the majority of bacterial strains, as mimicking their native environmental niches adequately can be a challenging task. Here, we report the diversity-driven cultivation, characterization and genome sequencing of 79 bacterial strains from all major taxonomic clades of the conspicuous bacterial phylum Planctomycetes. The samples were derived from different aquatic environments but close relatives could be isolated from geographically distinct regions and structurally diverse habitats, implying that 'everything is everywhere'. With the discovery of lateral budding in 'Kolteria novifilia' and the capability of the members of the Saltatorellus clade to divide by binary fission as well as budding, we identified previously unknown modes of bacterial cell division. Alongside unobserved aspects of cell signalling and small-molecule production, our findings demonstrate that exploration beyond the well-established model organisms has the potential to increase our knowledge of bacterial diversity. We illustrate how 'microbial dark matter' can be accessed by cultivation techniques, expanding the organismic background for small-molecule research and drug-target detection.
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Affiliation(s)
| | | | | | | | - John Vollmers
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Elena Rivas-Marín
- Centro Andaluz de Biología del Desarrollo (CABD)-CSIC, Pablo de Olavide University, Seville, Spain
| | - Timo Kohn
- Radboud University, Nijmegen, The Netherlands
| | | | - Anja Heuer
- Leibniz Institute DSMZ, Braunschweig, Germany
| | | | - Sonja Oberbeckmann
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ, Braunschweig, Germany
| | - Olga Jeske
- Leibniz Institute DSMZ, Braunschweig, Germany
| | | | | | | | | | | | | | | | | | | | | | - Matthias Labrenz
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany
| | | | | | | | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | | | | | | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo (CABD)-CSIC, Pablo de Olavide University, Seville, Spain
| | | | | | | | | | - Christian Jogler
- Radboud University, Nijmegen, The Netherlands. .,Friedrich Schiller University Jena, Jena, Germany.
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17
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Musiol-Kroll EM, Tocchetti A, Sosio M, Stegmann E. Challenges and advances in genetic manipulation of filamentous actinomycetes - the remarkable producers of specialized metabolites. Nat Prod Rep 2019; 36:1351-1369. [PMID: 31517370 DOI: 10.1039/c9np00029a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Covering: up to February 2019Actinomycetes are Gram positive bacteria of the phylum Actinobacteria. These organisms are one of the most important sources of structurally diverse, clinically used antibiotics and other valuable bioactive products, as well as biotechnologically relevant enzymes. Most strains were discovered by their ability to produce a given molecule and were often poorly characterized, physiologically and genetically. The development of genetic methods for Streptomyces and related filamentous actinomycetes has led to the successful manipulation of antibiotic biosynthesis to attain structural modification of microbial metabolites that would have been inaccessible by chemical means and improved production yields. Moreover, genome mining reveals that actinomycete genomes contain multiple biosynthetic gene clusters (BGCs), however only a few of them are expressed under standard laboratory conditions, leading to the production of the respective compound(s). Thus, to access and activate the so-called "silent" BGCs, to improve their biosynthetic potential and to discover novel natural products methodologies for genetic manipulation are required. Although different methods have been applied for many actinomycete strains, genetic engineering is still remaining very challenging for some "underexplored" and poorly characterized actinomycetes. This review summarizes the strategies developed to overcome the obstacles to genetic manipulation of actinomycetes and allowing thereby rational genetic engineering of this industrially relevant group of microorganisms. At the end of this review we give some tips to researchers with limited or no previous experience in genetic manipulation of actinomycetes. The article covers the most relevant literature published until February 2019.
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Affiliation(s)
- Ewa M Musiol-Kroll
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Microbiology/Biotechnology, Auf der Morgenstelle 28, Tübingen, 72076, Germany.
| | | | | | - Evi Stegmann
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Microbiology/Biotechnology, Auf der Morgenstelle 28, Tübingen, 72076, Germany.
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18
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Pinto D, Vecchione S, Wu H, Mauri M, Mascher T, Fritz G. Engineering orthogonal synthetic timer circuits based on extracytoplasmic function σ factors. Nucleic Acids Res 2019; 46:7450-7464. [PMID: 29986061 PMCID: PMC6101570 DOI: 10.1093/nar/gky614] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/26/2018] [Indexed: 01/02/2023] Open
Abstract
The rational design of synthetic regulatory circuits critically hinges on the availability of orthogonal and well-characterized building blocks. Here, we focus on extracytoplasmic function (ECF) σ factors, which are the largest group of alternative σ factors and hold extensive potential as synthetic orthogonal regulators. By assembling multiple ECF σ factors into regulatory cascades of varying length, we benchmark the scalability of the approach, showing that these ‘autonomous timer circuits’ feature a tuneable time delay between inducer addition and target gene activation. The implementation of similar timers in Escherichia coli and Bacillus subtilis shows strikingly convergent circuit behavior, which can be rationalized by a computational model. These findings not only reveal ECF σ factors as powerful building blocks for a rational, multi-layered circuit design, but also suggest that ECF σ factors are universally applicable as orthogonal regulators in a variety of bacterial species.
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Affiliation(s)
- Daniela Pinto
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062 Dresden, Germany
| | - Stefano Vecchione
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Hao Wu
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Marco Mauri
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062 Dresden, Germany
| | - Georg Fritz
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032 Marburg, Germany
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19
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Zakharevich NV, Nezametdinova VZ, Averina OV, Chekalina MS, Alekseeva MG, Danilenko VN. Complete Genome Sequence of Bifidobacterium angulatum GT102: Potential Genes and Systems of Communication with Host. RUSS J GENET+ 2019. [DOI: 10.1134/s1022795419070160] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Park JH, Lee JH, Roe JH. SigR, a hub of multilayered regulation of redox and antibiotic stress responses. Mol Microbiol 2019; 112:420-431. [PMID: 31269533 DOI: 10.1111/mmi.14341] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2019] [Indexed: 02/01/2023]
Abstract
Signal-specific activation of alternative sigma factors redirects RNA polymerase to induce transcription of distinct sets of genes conferring protection against the damage the signal and the related stresses incur. In Streptomyces coelicolor, σR (SigR), a member of ECF12 subfamily of Group IV sigma factors, responds to thiol-perturbing signals such as oxidants and electrophiles, as well as to translation-blocking antibiotics. Oxidants and electrophiles interact with and inactivate the zinc-containing anti-sigma factor, RsrA, via disulfide bond formation or alkylation of reactive cysteines, subsequently releasing σR for target gene induction. Translation-blocking antibiotics induce the synthesis of σR , via the WhiB-like transcription factor, WblC/WhiB7. Signal transduction via RsrA produces a dramatic transient response that involves positive feedback to produce more SigR as an unstable isoform σ R ' and negative feedbacks to degrade σ R ' , and reduce oxidized RsrA that subsequently sequester σR and σ R ' . Antibiotic stress brings about a prolonged response by increasing stable σR levels. The third negative feedback, which occurs via IF3, lowers the translation efficiency of the sigRp1 transcript that utilizes a non-canonical start codon. σR is a global regulator that directly activates > 100 transcription units in S. coelicolor, including genes for thiol homeostasis, protein quality control, sulfur metabolism, ribosome modulation and DNA repair. Close homologues in Actinobacteria, such as σH in Mycobacteria and Corynebacteria, show high conservation of the signal transduction pathways and target genes, thus reflecting the robustness of this type of regulation in response to redox and antibiotic stresses.
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Affiliation(s)
- Joo-Hong Park
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Ju-Hyung Lee
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Jung-Hye Roe
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
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21
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Otero-Asman JR, Wettstadt S, Bernal P, Llamas MA. Diversity of extracytoplasmic function sigma (σ ECF ) factor-dependent signaling in Pseudomonas. Mol Microbiol 2019; 112:356-373. [PMID: 31206859 DOI: 10.1111/mmi.14331] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2019] [Indexed: 12/23/2022]
Abstract
Pseudomonas bacteria are widespread and are found in soil and water, as well as pathogens of both plants and animals. The ability of Pseudomonas to colonize many different environments is facilitated by the multiple signaling systems these bacteria contain that allow Pseudomonas to adapt to changing circumstances by generating specific responses. Among others, signaling through extracytoplasmic function σ (σECF ) factors is extensively present in Pseudomonas. σECF factors trigger expression of functions required under particular conditions in response to specific signals. This manuscript reviews the phylogeny and biological roles of σECF factors in Pseudomonas, and highlights the diversity of σECF -signaling pathways of this genus in terms of function and activation. We show that Pseudomonas σECF factors belong to 16 different phylogenetic groups. Most of them are included within the iron starvation group and are mainly involved in iron acquisition. The second most abundant group is formed by RpoE-like σECF factors, which regulate the responses to cell envelope stress. Other groups controlling solvent tolerance, biofilm formation and the response to oxidative stress, among other functions, are present in lower frequency. The role of σECF factors in the virulence of Pseudomonas pathogenic species is described.
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Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Sarah Wettstadt
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Patricia Bernal
- Department of Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
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22
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Szurmant H. Evolutionary couplings of amino acid residues reveal structure and function of bacterial signaling proteins. Mol Microbiol 2019; 112:432-437. [PMID: 31102561 DOI: 10.1111/mmi.14282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2019] [Indexed: 12/12/2022]
Abstract
The genomic era along with major advances in high-throughput sequencing technology has led to a rapid expansion of the genomic and consequently the protein sequence space. Bacterial extracytoplasmic function sigma factors have emerged as an important group of signaling proteins in bacteria involved in many regulatory decisions, most notably the adaptation to cell envelope stress. Their wide prevalence and amplification among bacterial genomes has led to sub-group classification and the realization of diverse signaling mechanisms. Mathematical frameworks have been developed to utilize extensive protein sequence alignments to extract co-evolutionary signals of interaction. This has proven useful in a number of different biological fields, including de novo structure prediction, protein-protein partner identification and the elucidation of alternative protein conformations for signal proteins, to name a few. The mathematical tools, commonly referred to under the name 'Direct Coupling Analysis' have now been applied to deduce molecular mechanisms of activation for sub-groups of extracytoplasmic sigma factors adding to previous successes on bacterial two-component signaling proteins. The amplification of signal transduction protein genes in bacterial genomes made them the first to be amenable to this approach but the sequences are available now to aid the molecular microbiologist, no matter their protein pathway of interest.
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Affiliation(s)
- Hendrik Szurmant
- Basic Medical Science, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA
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23
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Moraleda-Muñoz A, Marcos-Torres FJ, Pérez J, Muñoz-Dorado J. Metal-responsive RNA polymerase extracytoplasmic function (ECF) sigma factors. Mol Microbiol 2019; 112:385-398. [PMID: 31187912 PMCID: PMC6851896 DOI: 10.1111/mmi.14328] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2019] [Indexed: 01/02/2023]
Abstract
In order to survive, bacteria must adapt to multiple fluctuations in their environment, including coping with changes in metal concentrations. Many metals are essential for viability, since they act as cofactors of indispensable enzymes. But on the other hand, they are potentially toxic because they generate reactive oxygen species or displace other metals from proteins, turning them inactive. This dual effect of metals forces cells to maintain homeostasis using a variety of systems to import and export them. These systems are usually inducible, and their expression is regulated by metal sensors and signal‐transduction mechanisms, one of which is mediated by extracytoplasmic function (ECF) sigma factors. In this review, we have focused on the metal‐responsive ECF sigma factors, several of which are activated by iron depletion (FecI, FpvI and PvdS), while others are activated by excess of metals such as nickel and cobalt (CnrH), copper (CarQ and CorE) or cadmium and zinc (CorE2). We focus particularly on their physiological roles, mechanisms of action and signal transduction pathways.
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Affiliation(s)
- Aurelio Moraleda-Muñoz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, E-18071, Spain
| | - Francisco Javier Marcos-Torres
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, E-18071, Spain.,Department of Cell and Molecular Biology, Uppsala University, Uppsala, 751 24, Sweden
| | - Juana Pérez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, E-18071, Spain
| | - José Muñoz-Dorado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, Granada, E-18071, Spain
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24
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Pinto D, Liu Q, Mascher T. ECF σ factors with regulatory extensions: the one-component systems of the σ universe. Mol Microbiol 2019; 112:399-409. [PMID: 31175685 DOI: 10.1111/mmi.14323] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2019] [Indexed: 12/18/2022]
Abstract
The σ subunit of the bacterial RNA polymerase determines promoter specificity. The extracytoplasmic function σ factors (ECFs) represent the most abundant and diverse group of alternative σ factors and are present in the vast majority of bacterial genomes. Typically, ECFs are regulated by anti-σ factors that sequester their cognate ECFs, thereby preventing their interaction with the RNA polymerase. Beyond these ECF paradigms, a number of distinct modes of regulation have been proposed and experimentally investigated. Regulatory extensions represent one such alternative mechanism of ECF regulation that can be found in 18 phylogenetically distinct ECF groups. Here, the σ factors contain additional domains that are fused to the ECF core domains and are involved in stimulus perception and modulation of σ factor activity. We will summarize the current state of knowledge on regulating ECF activity by C-terminal extensions. We will also discuss newly identified ECF groups containing either N- or C-terminal extensions and propose possible mechanisms by which these extensions have been generated and affect ECF σ factor activity. Based on their modular architecture and the resulting physical connection between stimulus perception and transcriptional output, these ECFs are analogous to one-component systems, the primary mechanism of bacterial signal transduction.
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Affiliation(s)
- Daniela Pinto
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany
| | - Qiang Liu
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany.,Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany
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25
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Wu H, Liu Q, Casas-Pastor D, Dürr F, Mascher T, Fritz G. The role of C-terminal extensions in controlling ECF σ factor activity in the widely conserved groups ECF41 and ECF42. Mol Microbiol 2019; 112:498-514. [PMID: 30990934 DOI: 10.1111/mmi.14261] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2019] [Indexed: 01/01/2023]
Abstract
The activity of extracytoplasmic function σ-factors (ECFs) is typically regulated by anti-σ factors. In a number of highly abundant ECF groups, including ECF41 and ECF42, σ-factors contain fused C-terminal protein domains, which provide the necessary regulatory function instead. Here, we identified the contact interface between the C-terminal extension and the core σ-factor regions required for controlling ECF activity. We applied direct coupling analysis (DCA) to infer evolutionary covariation between contacting amino acid residues for groups ECF41 and ECF42. Mapping the predicted interactions to a recently solved ECF41 structure demonstrated that DCA faithfully identified an important contact interface between the SnoaL-like extension and the linker between the σ2 and σ4 domains. Systematic alanine substitutions of contacting residues support this model and suggest that this interface stabilizes a compact conformation of ECF41 with low transcriptional activity. For group ECF42, DCA supports a structural homology model for their C-terminal tetratricopeptide repeat (TPR) domains and predicts an intimate contact between the first TPR-helix and the σ4 domain. Mutational analyses demonstrate the essentiality of the predicted interactions for ECF42 activity. These results indicate that C-terminal extensions indeed bind and regulate the core ECF regions, illustrating the potential of DCA for discovering regulatory motifs in the ECF subfamily.
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Affiliation(s)
- Hao Wu
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Qiang Liu
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062, Dresden, Germany.,Department Biology I, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Delia Casas-Pastor
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Franziska Dürr
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062, Dresden, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062, Dresden, Germany
| | - Georg Fritz
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, 35032, Marburg, Germany
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26
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Promoter RNA sequencing (PRSeq) for the massive and quantitative promoter analysis in vitro. Sci Rep 2019; 9:3118. [PMID: 30816266 PMCID: PMC6395800 DOI: 10.1038/s41598-019-39892-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 02/01/2019] [Indexed: 11/08/2022] Open
Abstract
Analysis of promoter strength and specificity is important for understanding and engineering gene regulation. Here, we report an in vitro promoter analysis method that can achieve both massiveness and quantitativeness. In this approach, a pool of single-stranded DNA with a partially randomized promoter sequence to be analyzed is chemically synthesized. Through enzymatic reactions, the randomized sequence will be copied to the downstream region, resulting in a template DNA pool that carries its own promoter information on its transcribed region. After in vitro transcription of the DNA pool with an RNA polymerase of interest, the sequences of the resulting transcripts will be analyzed. Since the promoter strength linearly correlates to the copy number of transcript, the strength of each promoter sequence can be evaluated. A model experiment of T7 promoter variants demonstrated the quantitativeness of the method, and the method was applied for the analysis of the promoter of cyanophage Syn5 RNA polymerase. This method provides a powerful approach for analyzing the complexity of promoter specificity and discrimination for highly abundant and often redundant alternative sigma factors such as the extracellular function (ECF) sigma factors.
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27
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Characterization of the Widely Distributed Novel ECF42 Group of Extracytoplasmic Function σ Factors in Streptomyces venezuelae. J Bacteriol 2018; 200:JB.00437-18. [PMID: 30126941 DOI: 10.1128/jb.00437-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 08/15/2018] [Indexed: 11/20/2022] Open
Abstract
Extracytoplasmic function σ factors (ECFs) represent the third most abundant fundamental principle of bacterial signal transduction, outranked only by one- and two-component systems. A recent census of ECFs revealed a large number of novel groups whose functions and regulatory mechanisms have not yet been elucidated. Here, we report the characterization of members of the novel group ECF42. ECF42 is a highly abundant and widely distributed ECF group that is present in 11 phyla but is predominantly found in Actinobacteria Analysis of the genomic context conservation did not identify a putative anti-σ factor. Instead, ECF42 genes are cotranscribed with genes encoding a conserved DGPF protein. We have experimentally verified the target promoter of these ECFs (TGTCGA in the -35 region and CGA/TC in the -10 region), which was found upstream of the ECF42-encoding operons in Streptomyces venezuelae, suggesting that ECF42s are positively autoregulated. RNA sequencing (RNA-seq) was performed to define the regulons of the three ECF42 proteins in S. venezuelae, which identified mostly genes encoding DGPF proteins. In contrast to typical ECFs, ECF42 proteins harbor a long C-terminal extension, which is crucial for their activity. Our work provides the first analysis of the function and regulatory mechanism of this novel ECF group that contains a regulatory C-terminal extension.IMPORTANCE In contrast to the one- and two-component signal transduction systems in bacteria, the importance and diversity of ECFs have only recently been recognized in the course of comprehensive phylogenetic and comparative genomics studies. Thus, most of the ECFs still have not been experimentally characterized regarding their physiological functions and regulation mechanisms so far. The physiological roles, target promoter, and target regulons of a novel group of ECFs, ECF42, in S. venezuelae have been investigated in this work. More importantly, members of this group are characterized by a C-terminal extension, which has been verified to harbor a regulatory role in ECF42s. Hence, our work provides an important source for further research on such C-terminal extension containing ECFs.
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Hoskisson PA, Fernández‐Martínez LT. Regulation of specialised metabolites in Actinobacteria - expanding the paradigms. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:231-238. [PMID: 29457705 PMCID: PMC6001450 DOI: 10.1111/1758-2229.12629] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 06/01/2023]
Abstract
The increase in availability of actinobacterial whole genome sequences has revealed huge numbers of specialised metabolite biosynthetic gene clusters, encoding a range of bioactive molecules such as antibiotics, antifungals, immunosuppressives and anticancer agents. Yet the majority of these clusters are not expressed under standard laboratory conditions in rich media. Emerging data from studies of specialised metabolite biosynthesis suggest that the diversity of regulatory mechanisms is greater than previously thought and these act at multiple levels, through a range of signals such as nutrient limitation, intercellular signalling and competition with other organisms. Understanding the regulation and environmental cues that lead to the production of these compounds allows us to identify the role that these compounds play in their natural habitat as well as provide tools to exploit this untapped source of specialised metabolites for therapeutic uses. Here, we provide an overview of novel regulatory mechanisms that act in physiological, global and cluster-specific regulatory manners on biosynthetic pathways in Actinobacteria and consider these alongside their ecological and evolutionary implications.
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Affiliation(s)
- Paul A. Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical SciencesUniversity of Strathclyde, 161 Cathedral StreetGlasgow G4 0REUK
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29
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Bouillet S, Arabet D, Jourlin-Castelli C, Méjean V, Iobbi-Nivol C. Regulation of σ factors by conserved partner switches controlled by divergent signalling systems. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:127-139. [PMID: 29393573 DOI: 10.1111/1758-2229.12620] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 06/07/2023]
Abstract
Partner-Switching Systems (PSS) are widespread regulatory systems, each comprising a kinase-anti-σ, a phosphorylatable anti-σ antagonist and a phosphatase module. The anti-σ domain quickly sequesters or delivers the target σ factor according to the phosphorylation state of the anti-σ antagonist induced by environmental signals. The PSS components are proteins alone or merged to other domains probably to adapt to the input signals. PSS are involved in major cellular processes including stress response, sporulation, biofilm formation and pathogenesis. Surprisingly, the target σ factors are often unknown and the sensing modules acting upstream from the PSS diverge according to the bacterial species. Indeed, they belong to either two-component systems or complex pathways as the stressosome or Chemosensory Systems (CS). Based on a phylogenetic analysis, we propose that the sensing module in Gram-negative bacteria is often a CS.
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Affiliation(s)
- Sophie Bouillet
- Aix-Marseille University, CNRS, BIP UMR7281, 13402 Marseille, France
| | - Dallel Arabet
- Université des Frères Mentouri Constantine 1, Constantine, Algeria
| | | | - Vincent Méjean
- Aix-Marseille University, CNRS, BIP UMR7281, 13402 Marseille, France
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30
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López-García MT, Yagüe P, González-Quiñónez N, Rioseras B, Manteca A. The SCO4117 ECF Sigma Factor Pleiotropically Controls Secondary Metabolism and Morphogenesis in Streptomyces coelicolor. Front Microbiol 2018. [PMID: 29515563 PMCID: PMC5826349 DOI: 10.3389/fmicb.2018.00312] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Extracytoplasmic function (ECF) sigma factors are a major type of bacterial signal-transducers whose biological functions remain poorly characterized in streptomycetes. In this work we studied SCO4117, a conserved ECF sigma factor from the ECF52 family overexpressed during substrate and aerial mycelium stages. The ECF52 sigma factors harbor, in addition to the ECF sigma factor domain, a zinc finger domain, a transmembrane region, a proline-rich C-terminal extension, and a carbohydrate-binding domain. This class of ECF sigma factors is exclusive to Actinobacteria. We demonstrate that SCO4117 is an activator of secondary metabolism, aerial mycelium differentiation, and sporulation, in all the culture media (sucrose-free R5A, GYM, MM, and SFM) analyzed. Aerial mycelium formation and sporulation are delayed in a SCO4117 knockout strain. Actinorhodin production is delayed and calcium-dependent antibiotic production is diminished, in the ΔSCO4117 mutant. By contast, undecylprodigiosin production do not show significant variations. The expression of genes encoding secondary metabolism pathways (deoxysugar synthases, actinorhodin biosynthetic genes) and genes involved in differentiation (rdl, chp, nepA, ssgB) was dramatically reduced (up to 300-fold) in the SCO4117 knockout. A putative motif bound, with the consensus “CSGYN-17bps-SRHA” sequence, was identified in the promoter region of 29 genes showing affected transcription in the SCO4117 mutant, including one of the SCO4117 promoters. SCO4117 is a conserved gene with complex regulation at the transcriptional and post-translational levels and the first member of the ECF52 family characterized.
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Affiliation(s)
- María T López-García
- Área de Microbiología, Departamento de Biología Funcional e IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Paula Yagüe
- Área de Microbiología, Departamento de Biología Funcional e IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Nathaly González-Quiñónez
- Área de Microbiología, Departamento de Biología Funcional e IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Beatriz Rioseras
- Área de Microbiología, Departamento de Biología Funcional e IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Angel Manteca
- Área de Microbiología, Departamento de Biología Funcional e IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
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31
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Kleine B, Chattopadhyay A, Polen T, Pinto D, Mascher T, Bott M, Brocker M, Freudl R. The three-component system EsrISR regulates a cell envelope stress response in Corynebacterium glutamicum. Mol Microbiol 2017; 106:719-741. [PMID: 28922502 DOI: 10.1111/mmi.13839] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 02/03/2023]
Abstract
When the cell envelope integrity is compromised, bacteria trigger signaling cascades resulting in the production of proteins that counteract these extracytoplasmic stresses. Here, we show that the two-component system EsrSR regulates a cell envelope stress response in the Actinobacterium Corynebacterium glutamicum. The sensor kinase EsrS possesses an amino-terminal phage shock protein C (PspC) domain, a property that sets EsrSR apart from all other two-component systems characterized so far. An integral membrane protein, EsrI, whose gene is divergently transcribed to the esrSR gene locus and which interestingly also possesses a PspC domain, acts as an inhibitor of EsrSR under non-stress conditions. The resulting EsrISR three-component system is activated among others by antibiotics inhibiting the lipid II cycle, such as bacitracin and vancomycin, and it orchestrates a broad regulon including the esrI-esrSR gene locus itself, genes encoding heat shock proteins, ABC transporters, and several putative membrane-associated or secreted proteins of unknown function. Among those, the ABC transporter encoded by cg3322-3320 was shown to be directly involved in bacitracin resistance of C. glutamicum. Since similar esrI-esrSR loci are present in a large number of actinobacterial genomes, EsrISR represents a novel type of stress-responsive system whose components are highly conserved in the phylum Actinobacteria.
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Affiliation(s)
- Britta Kleine
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
| | - Ava Chattopadhyay
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
| | - Tino Polen
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
| | - Daniela Pinto
- Institut für Mikrobiologie, Technische Universität Dresden, Zellescher Weg 20b, Dresden D-01217, Germany
| | - Thorsten Mascher
- Institut für Mikrobiologie, Technische Universität Dresden, Zellescher Weg 20b, Dresden D-01217, Germany
| | - Michael Bott
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
| | - Melanie Brocker
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
| | - Roland Freudl
- Institut für Bio- und Geowissenschaften 1, Biotechnologie, Forschungszentrum Jülich GmbH, Jülich D-52425, Germany
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Patel S, Rani A, Goyal A. Insights into the immune manipulation mechanisms of pollen allergens by protein domain profiling. Comput Biol Chem 2017; 70:31-39. [PMID: 28780227 DOI: 10.1016/j.compbiolchem.2017.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/13/2017] [Accepted: 07/26/2017] [Indexed: 11/25/2022]
Abstract
Plant pollens are airborne allergens, as their inhalation causes immune activation, leading to rhinitis, conjunctivitis, sinusitis and oral allergy syndrome. A myriad of pollen proteins belonging to profilin, expansin, polygalacturonase, glucan endoglucosidase, pectin esterase, and lipid transfer protein class have been identified. In the present in silico study, the protein domains of fifteen pollen sequences were extracted from the UniProt database and submitted to the interactive web tool SMART (Simple Modular Architecture Research Tool), for finding the protein domain profiles. Analysis of the data based on custom-made scripts revealed the conservation of pathogenic domains such as OmpH, PROF, PreSET, Bet_v_1, Cpl-7 and GAS2. Further, the retention of critical domains like CHASE2, Galanin, Dak2, DALR_1, HAMP, PWI, EFh, Excalibur, CT, PbH1, HELICc, and Kelch in pollen proteins, much like cockroach allergens and lethal viruses (such as HIV, HCV, Ebola, Dengue and Zika) was observed. Based on the shared motifs in proteins of taxonomicall-ydispersed organisms, it can be hypothesized that allergens and pathogens manipulate the human immune system in a similar manner. Allergens, being inanimate, cannot replicate in human body, and are neutralized by immune system. But, when the allergens are unremitting, the immune system becomes persistently hyper-sensitized, creating an inflammatory milieu. This study is expected to contribute to the understanding of pollen allergenicity and pathogenicity.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA.
| | - Aruna Rani
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Arun Goyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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Sineva E, Savkina M, Ades SE. Themes and variations in gene regulation by extracytoplasmic function (ECF) sigma factors. Curr Opin Microbiol 2017; 36:128-137. [PMID: 28575802 DOI: 10.1016/j.mib.2017.05.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/15/2017] [Accepted: 05/13/2017] [Indexed: 01/08/2023]
Abstract
The ECF sigma family was identified 23 years ago as a distinct group of σ70-like factors. ECF sigma factors have since emerged as a major form of bacterial signal transduction that can be grouped into over 50 phylogenetically distinct subfamilies. Advances in our understanding of these sigma factors and the signaling pathways governing their activity have elucidated conserved features as well as aspects that have evolved over time. All ECF sigma factors are predicted to share a common streamlined domain structure and mode of promoter interaction. The activity of most ECF sigma factors is controlled by an anti-sigma factor. The nature of the anti-sigma factor and the activating signaling pathways appear to be conserved within ECF families, while considerable diversity exists between different families.
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Affiliation(s)
- Elena Sineva
- Department of Biochemistry and Molecular Biology, 408 Althouse Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - Maria Savkina
- Department of Biochemistry and Molecular Biology, 408 Althouse Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sarah E Ades
- Department of Biochemistry and Molecular Biology, 408 Althouse Laboratory, The Pennsylvania State University, University Park, PA 16802, USA.
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34
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Patel S. Pathogenicity-associated protein domains: The fiercely-conserved evolutionary signatures. GENE REPORTS 2017; 7:127-141. [PMID: 32363241 PMCID: PMC7185390 DOI: 10.1016/j.genrep.2017.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/29/2017] [Accepted: 04/07/2017] [Indexed: 12/15/2022]
Abstract
Proteins have highly conserved domains that determine their functionality. Out of the thousands of domains discovered so far across all living forms, some of the predominant clinically-relevant domains include IENR1, HNHc, HELICc, Pro-kuma_activ, Tryp_SPc, Lactamase_B, PbH1, ChtBD3, CBM49, acidPPc, G3P_acyltransf, RPOL8c, KbaA, HAMP, HisKA, Hr1, Dak2, APC2, Citrate_ly_lig, DALR, VKc, YARHG, WR1, PWI, ZnF_BED, TUDOR, MHC_II_beta, Integrin_B_tail, Excalibur, DISIN, Cadherin, ACTIN, PROF, Robl_LC7, MIT, Kelch, GAS2, B41, Cyclin_C, Connexin_CCC, OmpH, Bac_rhodopsin, AAA, Knot1, NH, Galanin, IB, Elicitin, ACTH, Cache_2, CHASE, AgrB, PRP, IGR, and Antimicrobial21. These domains are distributed in nucleases/helicases, proteases, esterases, lipases, glycosylase, GTPases, phosphatases, methyltransferases, acyltransferase, acetyltransferase, polymerase, kinase, ligase, synthetase, oxidoreductase, protease inhibitors, nucleic acid binding proteins, adhesion and immunity-related proteins, cytoskeletal component-manipulating proteins, lipid biosynthesis and metabolism proteins, membrane-associated proteins, hormone-like and signaling proteins, etc. These domains are ubiquitous stretches or folds of the proteins in pathogens and allergens. Pathogenesis alleviation efforts can benefit enormously if the characteristics of these domains are known. Hence, this review catalogs and discusses the role of such pivotal domains, suggesting hypotheses for better understanding of pathogenesis at molecular level. Proteins have highly conserved regions or domains across pathogens and allergens. Knowledge on these critical domains can facilitate our understanding of pathogenesis mechanisms. Such immune manipulation-related domains include IENR1, HNHc, HELICc, ACTIN, PROF, Robl_LC7, OmpH etc. These domains are presnt in enzyme, transcription regulators, adhesion proteins, and hormones. This review discusses and hypothesizes on these domains.
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Key Words
- CARDs, caspase activation and recruitment domains
- CBM, carbohydrate binding module
- CTD, C-terminal domain
- ChtBD, chitin-binding domain
- Diversification
- HNHc, homing endonucleases
- HTH, helix-turn-helix
- IENR1, intron-encoded endonuclease repeat
- Immune manipulation
- PAMPs, pathogen associated molecular patterns
- Pathogenesis
- Phylogenetic conservation
- Protein domains
- SMART, Simple Modular Architecture Research Tool
- Shuffling
- UDG, uracil DNA glycosylase
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA
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35
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Patel S. In silico analysis of Hepatitis C virus (HCV) polyprotein domains and their comparison with other pathogens and allergens to gain insight on pathogenicity mechanisms. Comput Biol Chem 2016; 65:91-102. [DOI: 10.1016/j.compbiolchem.2016.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/12/2016] [Accepted: 10/11/2016] [Indexed: 12/12/2022]
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36
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Zhang S, Gedalanga PB, Mahendra S. Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9599-9607. [PMID: 27486928 DOI: 10.1021/acs.est.6b02797] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study investigated the impacts of individual chlorinated solvents and their mixtures on aerobic 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190. The established association of these co-occurring compounds suggests important considerations for their respective biodegradation processes. Our kinetics and mechanistic studies demonstrated that individual solvents inhibited biodegradation of 1,4-dioxane in the following order: 1,1-dichloroethene (1,1-DCE) > cis-1,2-diochloroethene (cDCE) > trichloroethene (TCE) > 1,1,1-trichloroethane (TCA). The presence of 5 mg L(-1) 1,1-DCE completely inhibited 1,4-dioxane biodegradation. Subsequently, we determined that 1,1-DCE was the strongest inhibitor of 1,4-dioxane biodegradation by bacterial pure cultures exposed to chlorinated solvent mixtures as well as in environmental samples collected from a site contaminated with chlorinated solvents and 1,4-dioxane. Inhibition of 1,4-dioxane biodegradation rates by chlorinated solvents was attributed to delayed ATP production and down-regulation of both 1,4-dioxane monooxygenase (dxmB) and aldehyde dehydrogenase (aldH) genes. Moreover, increasing concentrations of 1,1-DCE and cis-1,2-DCE to 50 mg L(-1) respectively increased 5.0-fold and 3.5-fold the expression of the uspA gene encoding a universal stress protein. In situ natural attenuation or enhanced biodegradation of 1,4-dioxane is being considered for contaminated groundwater and industrial wastewater, so these results will have implications for selecting 1,4-dioxane bioremediation strategies at sites where chlorinated solvents are present as co-contaminants.
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Affiliation(s)
- Shu Zhang
- Department of Civil and Environmental Engineering, University of California , Los Angeles, California 90095, United States
| | - Phillip B Gedalanga
- Department of Civil and Environmental Engineering, University of California , Los Angeles, California 90095, United States
| | - Shaily Mahendra
- Department of Civil and Environmental Engineering, University of California , Los Angeles, California 90095, United States
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(Actino)Bacterial “intelligence”: using comparative genomics to unravel the information processing capacities of microbes. Curr Genet 2016; 62:487-98. [DOI: 10.1007/s00294-016-0569-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/20/2016] [Accepted: 01/22/2016] [Indexed: 01/24/2023]
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