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Polymorphisms of dtxR Gene of Corynebacterium diphtheriae Isolated from Diphtheria Outbreak in Indonesia. Jundishapur J Microbiol 2022. [DOI: 10.5812/jjm-121534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: In Corynebacterium diphtheriae, the dtxR gene plays a role in regulating diphtheria toxin synthesis. The dtxR gene is often used as a marker for identifying C. diphtheriae by the polymerase chain reaction (PCR) method because it is present in all strains of this bacterium. Mutations in the dtxR gene can cause the over-synthesis of diphtheria toxin and reduce PCR assays' sensitivity. Objectives: This study aimed to describe the polymorphisms in the dtxR gene of C. diphtheriae isolated from a diphtheria outbreak in Indonesia. Methods: Forty-eight isolates of C. diphtheriae were obtained from clinical samples (throat/nasopharyngeal swabs) of diphtheria cases and close contacts. The isolates were revived on a Blood Agar Plate (BAP), bacterial colonies were harvested, and deoxyribonucleic acid (DNA) was extracted. The DNA sequencing was carried out using a Whole-genome Sequencing (WGS) approach. The data were converted and analyzed with U-gene software. The dtxR gene analysis was performed with C. diphtheriae PW8 as references. Results: There were 59-point mutation locations in 48 isolates examined. None of these single nucleotide polymorphisms (SNPs) coded for amino acid changes. Based on the mutation pattern, seven clades/groups of the dtxR gene of 48 C. diphtheriae isolates were examined. Conclusions: At least seven types of DNA sequences and more than 50 SNPs of the dtxR gene were identified in 48 C. diphtheriae isolates from a diphtheria outbreak in Indonesia. Although all of them are silent mutations, they must be considered in the design of PCR examination in diphtheria laboratories.
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Möller J, Nosratabadi F, Musella L, Hofmann J, Burkovski A. Corynebacterium diphtheriae Proteome Adaptation to Cell Culture Medium and Serum. Proteomes 2021; 9:proteomes9010014. [PMID: 33805816 PMCID: PMC8005964 DOI: 10.3390/proteomes9010014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/03/2022] Open
Abstract
Host-pathogen interactions are often studied in vitro using primary or immortal cell lines. This set-up avoids ethical problems of animal testing and has the additional advantage of lower costs. However, the influence of cell culture media on bacterial growth and metabolism is not considered or investigated in most cases. To address this question growth and proteome adaptation of Corynebacterium diphtheriae strain ISS3319 were investigated in this study. Bacteria were cultured in standard growth medium, cell culture medium, and fetal calf serum. Mass spectrometric analyses and label-free protein quantification hint at an increased bacterial pathogenicity when grown in cell culture medium as well as an influence of the growth medium on the cell envelope.
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Affiliation(s)
- Jens Möller
- Microbiology Division, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany; (F.N.); (L.M.); (A.B.)
- Correspondence: ; Tel.: +49-9131-85-28802
| | - Fatemeh Nosratabadi
- Microbiology Division, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany; (F.N.); (L.M.); (A.B.)
| | - Luca Musella
- Microbiology Division, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany; (F.N.); (L.M.); (A.B.)
| | - Jörg Hofmann
- Biochemistry Division, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany;
| | - Andreas Burkovski
- Microbiology Division, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany; (F.N.); (L.M.); (A.B.)
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Sharma NC, Efstratiou A, Mokrousov I, Mutreja A, Das B, Ramamurthy T. Diphtheria. Nat Rev Dis Primers 2019; 5:81. [PMID: 31804499 DOI: 10.1038/s41572-019-0131-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 01/09/2023]
Abstract
Diphtheria is a potentially fatal infection mostly caused by toxigenic Corynebacterium diphtheriae strains and occasionally by toxigenic C. ulcerans and C. pseudotuberculosis strains. Diphtheria is generally an acute respiratory infection, characterized by the formation of a pseudomembrane in the throat, but cutaneous infections are possible. Systemic effects, such as myocarditis and neuropathy, which are associated with increased fatality risk, are due to diphtheria toxin, an exotoxin produced by the pathogen that inhibits protein synthesis and causes cell death. Clinical diagnosis is confirmed by the isolation and identification of the causative Corynebacterium spp., usually by bacterial culture followed by enzymatic and toxin detection tests. Diphtheria can be treated with the timely administration of diphtheria antitoxin and antimicrobial therapy. Although effective vaccines are available, this disease has the potential to re-emerge in countries where the recommended vaccination programmes are not sustained, and increasing proportions of adults are becoming susceptible to diphtheria. Thousands of diphtheria cases are still reported annually from several countries in Asia and Africa, along with many outbreaks. Changes in the epidemiology of diphtheria have been reported worldwide. The prevalence of toxigenic Corynebacterium spp. highlights the need for proper clinical and epidemiological investigations to quickly identify and treat affected individuals, along with public health measures to prevent and contain the spread of this disease.
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Affiliation(s)
- Naresh Chand Sharma
- Laboratory Department, Maharishi Valmiki Infectious Diseases Hospital, Delhi, India
| | - Androulla Efstratiou
- WHO Collaborating Centre for Diphtheria and Streptococcal Infections, Reference Microbiology Division, Public Health England, London, UK
| | - Igor Mokrousov
- Laboratory of Molecular Epidemiology and Evolutionary Genetics, St. Petersburg Pasteur Institute, St. Petersburg, Russia
| | - Ankur Mutreja
- Global Health-Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Bhabatosh Das
- Infection and Immunology Division, Translational Health Science and Technology Institute, Faridabad, India
| | - Thandavarayan Ramamurthy
- Infection and Immunology Division, Translational Health Science and Technology Institute, Faridabad, India.
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Bethke J, Yáñez AJ, Avendaño-Herrera R. Comparative Genomic Analysis of Two Chilean Renibacterium salmoninarum Isolates and the Type Strain ATCC 33209T. Genome Biol Evol 2018; 10:1816-1822. [PMID: 29982426 PMCID: PMC6057502 DOI: 10.1093/gbe/evy138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2018] [Indexed: 11/29/2022] Open
Abstract
Renibacterium salmoninarum, a slow-growing facultative intracellular pathogen belonging to the high C + G content Actinobacteria phylum, is the causative agent of bacterial kidney disease, a progressive granulomatous infection affecting salmonids worldwide. This Gram-positive bacterium has existed in the Chilean salmonid industry for >30 years, but little or no information is available regarding the virulence mechanisms and genomic characteristics of Chilean isolates. In this study, the genomes of two Chilean isolates (H-2 and DJ2R) were sequenced, and a search was conducted for genes and proteins involved in virulence and pathogenicity, and we compare with the type strain ATCC 33209 T genome. The genome sizes of H-2 and DJ2R are 3,155,332 bp and 3,155,228 bp, respectively. They genomes presented six ribosomal RNA, 46 transcription RNA, and 25 noncodingRNA, and both had the same 56.27% G + C content described for the type strain ATCC 33209 T. A total of 3,522 and 3,527 coding sequences were found for H-2 and DJ2R, respectively. Meanwhile, the ATCC 33209 T type strain had 3,519 coding sequences. The in silico genome analysis revealed a genes related to tricarboxylic acid cycle, glycolysis, iron transport and others metabolic pathway. Also, the data indicated that R salmoninarum may have a variety of possible virulence-factor and antibiotic-resistance strategies. Interestingly, many of genes had high identities with Mycobacterium species, a known pathogenic Actinobacteria bacterium. In summary, this study provides the first insights into and initial steps towards understanding the molecular basis of antibiotic resistance, virulence mechanisms and host/environment adaptation in two Chilean R. salmoninarum isolates that contain proteins of which were similar to those of Mycobacterium. Furthermore, important information is presented that could facilitate the development of preventive and treatment measures against R. salmoninarum in Chile and worldwide.
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Affiliation(s)
- Jorn Bethke
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Viña del Mar, Chile.,Interdisciplinary Center for Aquaculture Research (INCAR), Viña del Mar, Chile
| | - Alejandro J Yáñez
- Interdisciplinary Center for Aquaculture Research (INCAR), Viña del Mar, Chile.,Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Ruben Avendaño-Herrera
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Viña del Mar, Chile.,Interdisciplinary Center for Aquaculture Research (INCAR), Viña del Mar, Chile.,Centro de Investigación Marina Quintay (CIMARQ), Universidad Andrés Bello, Quintay, Chile
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5
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Abstract
Pathogenic bacteria must withstand diverse host environments during infection. Environmental signals, such as pH, temperature, nutrient limitation, etc., not only trigger adaptive responses within bacteria to these specific stress conditions but also direct the expression of virulence genes at an appropriate time and place. An appreciation of stress responses and their regulation is therefore essential for an understanding of bacterial pathogenesis. This review considers specific stresses in the host environment and their relevance to pathogenesis, with a particular focus on the enteric pathogen Salmonella.
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Affiliation(s)
- Ferric C Fang
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195-7735, USA; Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195-7735, USA.
| | - Elaine R Frawley
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195-7735, USA
| | - Timothy Tapscott
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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AlQuraishi M, Tang S, Xia X. An affinity-structure database of helix-turn-helix: DNA complexes with a universal coordinate system. BMC Bioinformatics 2015; 16:390. [PMID: 26586237 PMCID: PMC4653904 DOI: 10.1186/s12859-015-0819-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 11/11/2015] [Indexed: 11/28/2022] Open
Abstract
Background Molecular interactions between proteins and DNA molecules underlie many cellular processes, including transcriptional regulation, chromosome replication, and nucleosome positioning. Computational analyses of protein-DNA interactions rely on experimental data characterizing known protein-DNA interactions structurally and biochemically. While many databases exist that contain either structural or biochemical data, few integrate these two data sources in a unified fashion. Such integration is becoming increasingly critical with the rapid growth of structural and biochemical data, and the emergence of algorithms that rely on the synthesis of multiple data types to derive computational models of molecular interactions. Description We have developed an integrated affinity-structure database in which the experimental and quantitative DNA binding affinities of helix-turn-helix proteins are mapped onto the crystal structures of the corresponding protein-DNA complexes. This database provides access to: (i) protein-DNA structures, (ii) quantitative summaries of protein-DNA binding affinities using position weight matrices, and (iii) raw experimental data of protein-DNA binding instances. Critically, this database establishes a correspondence between experimental structural data and quantitative binding affinity data at the single basepair level. Furthermore, we present a novel alignment algorithm that structurally aligns the protein-DNA complexes in the database and creates a unified residue-level coordinate system for comparing the physico-chemical environments at the interface between complexes. Using this unified coordinate system, we compute the statistics of atomic interactions at the protein-DNA interface of helix-turn-helix proteins. We provide an interactive website for visualization, querying, and analyzing this database, and a downloadable version to facilitate programmatic analysis. Conclusions This database will facilitate the analysis of protein-DNA interactions and the development of programmatic computational methods that capitalize on integration of structural and biochemical datasets. The database can be accessed at http://ProteinDNA.hms.harvard.edu.
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Affiliation(s)
- Mohammed AlQuraishi
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA. .,HMS Laboratory of Systems Pharmacology, Harvard Medical School, 200 Longwood Avenue, Boston, MA, 02115, USA.
| | - Shengdong Tang
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA.,HMS Laboratory of Systems Pharmacology, Harvard Medical School, 200 Longwood Avenue, Boston, MA, 02115, USA
| | - Xide Xia
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA.,HMS Laboratory of Systems Pharmacology, Harvard Medical School, 200 Longwood Avenue, Boston, MA, 02115, USA
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Abstract
This study investigates the mechanisms of UV-A (315 to 400 nm) photocatalysis with titanium dioxide (TiO2) applied to the degradation of Escherichia coli and their effects on two key cellular components: lipids and proteins. The impact of TiO2 photocatalysis on E. coli survival was monitored by counting on agar plate and by assessing lipid peroxidation and performing proteomic analysis. We observed through malondialdehyde quantification that lipid peroxidation occurred during the photocatalytic process, and the addition of superoxide dismutase, which acts as a scavenger of the superoxide anion radical (O2·(-)), inhibited this effect by half, showing us that O2·(-) radicals participate in the photocatalytic antimicrobial effect. Qualitative analysis using two-dimensional electrophoresis allowed selection of proteins for which spot modifications were observed during the applied treatments. Two-dimensional electrophoresis highlighted that among the selected protein spots, 7 and 19 spots had already disappeared in the dark in the presence of 0.1 g/liter and 0.4 g/liter TiO2, respectively, which is accounted for by the cytotoxic effect of TiO2. Exposure to 30 min of UV-A radiation in the presence of 0.1 g/liter and 0.4 g/liter TiO2 increased the numbers of missing spots to 14 and 22, respectively. The proteins affected by photocatalytic oxidation were strongly heterogeneous in terms of location and functional category. We identified several porins, proteins implicated in stress response, in transport, and in bacterial metabolism. This study reveals the simultaneous effects of O2·(-) on lipid peroxidation and on the proteome during photocatalytic treatment and therefore contributes to a better understanding of molecular mechanisms in antibacterial photocatalytic treatment.
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Cloning, expression, purification and characterization of an iron-dependent regulator protein from Thermobifida fusca. Protein Expr Purif 2013; 92:190-4. [PMID: 24084005 DOI: 10.1016/j.pep.2013.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/15/2013] [Accepted: 09/17/2013] [Indexed: 11/22/2022]
Abstract
Iron-dependent regulators (IdeRs) control the transcription of a variety of genes associated with iron homeostasis in Gram-positive bacteria. In this study we report the cloning of a putative IdeR gene from the moderate thermophile Thermobifida fusca into the pET-21a(+) expression vector. The expressed protein, Tf-IdeR, was purified using immobilized metal affinity and size-exclusion chromatography, and yielded approximately 12-16 mg of protein per liter of culture. The purified Tf-IdeR protein binds the tox operator sequence in the presence of divalent metal ions. Two Tf-IdeR binding sites were identified in the T. fusca genome upstream of a putative enterobactin exporter and a putative ABC-type multidrug transporter.
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9
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Merchant AT, Spatafora GA. A role for the DtxR family of metalloregulators in gram-positive pathogenesis. Mol Oral Microbiol 2013; 29:1-10. [PMID: 24034418 DOI: 10.1111/omi.12039] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2013] [Indexed: 11/28/2022]
Abstract
Given the central role of transition metal ions in a variety of biochemical processes, the colonization, survival, and proliferation of a bacterium within a host hinges upon its ability to overcome the metal ion deprivation that characterizes nutritional immunity. Metalloregulatory, or 'metal-sensing' proteins have evolved in bacteria to mediate metal ion homeostasis by activating or repressing the expression of genes encoding metal ion transport systems upon binding their cognate metal ion. Yet increasing evidence in the literature supports an additional role for these metalloregulatory proteins in pathogenesis. Herein, we survey studies on the DtxR family of metalloregulators, namely DtxR (Cornyebacterium diphtheriae), SloR (Streptococcus mutans), MtsR (Streptococcus pyogenes), and MntR (Staphylococcus aureus) to describe how metalloregulation enables adaptive virulence gene expression within the mammalian host. This research has important implications for drug design, as the generation of hyper-repressive metalloregulatory proteins may represent a mechanism by which to attenuate bacterial pathogenicity. The fact that metalloregulators are unique to prokaryotes makes these proteins especially attractive therapeutic targets.
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Affiliation(s)
- A T Merchant
- Department of Biology, Middlebury College, Middlebury, VT, USA
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10
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AlQuraishi M, McAdams HH. Three enhancements to the inference of statistical protein-DNA potentials. Proteins 2012; 81:426-42. [PMID: 23042633 DOI: 10.1002/prot.24201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/17/2012] [Accepted: 10/02/2012] [Indexed: 12/28/2022]
Abstract
The energetics of protein-DNA interactions are often modeled using so-called statistical potentials, that is, energy models derived from the atomic structures of protein-DNA complexes. Many statistical protein-DNA potentials based on differing theoretical assumptions have been investigated, but little attention has been paid to the types of data and the parameter estimation process used in deriving the statistical potentials. We describe three enhancements to statistical potential inference that significantly improve the accuracy of predicted protein-DNA interactions: (i) incorporation of binding energy data of protein-DNA complexes, in conjunction with their X-ray crystal structures, (ii) use of spatially-aware parameter fitting, and (iii) use of ensemble-based parameter fitting. We apply these enhancements to three widely-used statistical potentials and use the resulting enhanced potentials in a structure-based prediction of the DNA binding sites of proteins. These enhancements are directly applicable to all statistical potentials used in protein-DNA modeling, and we show that they can improve the accuracy of predicted DNA binding sites by up to 21%.
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Affiliation(s)
- Mohammed AlQuraishi
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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Leigh JW, Lapointe FJ, Lopez P, Bapteste E. Evaluating phylogenetic congruence in the post-genomic era. Genome Biol Evol 2011; 3:571-87. [PMID: 21712432 PMCID: PMC3156567 DOI: 10.1093/gbe/evr050] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2011] [Indexed: 12/04/2022] Open
Abstract
Congruence is a broadly applied notion in evolutionary biology used to justify multigene phylogeny or phylogenomics, as well as in studies of coevolution, lateral gene transfer, and as evidence for common descent. Existing methods for identifying incongruence or heterogeneity using character data were designed for data sets that are both small and expected to be rarely incongruent. At the same time, methods that assess incongruence using comparison of trees test a null hypothesis of uncorrelated tree structures, which may be inappropriate for phylogenomic studies. As such, they are ill-suited for the growing number of available genome sequences, most of which are from prokaryotes and viruses, either for phylogenomic analysis or for studies of the evolutionary forces and events that have shaped these genomes. Specifically, many existing methods scale poorly with large numbers of genes, cannot accommodate high levels of incongruence, and do not adequately model patterns of missing taxa for different markers. We propose the development of novel incongruence assessment methods suitable for the analysis of the molecular evolution of the vast majority of life and support the investigation of homogeneity of evolutionary process in cases where markers do not share identical tree structures.
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Affiliation(s)
- Jessica W Leigh
- Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand.
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12
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Trost E, Ott L, Schneider J, Schröder J, Jaenicke S, Goesmann A, Husemann P, Stoye J, Dorella FA, Rocha FS, Soares SDC, D'Afonseca V, Miyoshi A, Ruiz J, Silva A, Azevedo V, Burkovski A, Guiso N, Join-Lambert OF, Kayal S, Tauch A. The complete genome sequence of Corynebacterium pseudotuberculosis FRC41 isolated from a 12-year-old girl with necrotizing lymphadenitis reveals insights into gene-regulatory networks contributing to virulence. BMC Genomics 2010; 11:728. [PMID: 21192786 PMCID: PMC3022926 DOI: 10.1186/1471-2164-11-728] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 12/30/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Corynebacterium pseudotuberculosis is generally regarded as an important animal pathogen that rarely infects humans. Clinical strains are occasionally recovered from human cases of lymphadenitis, such as C. pseudotuberculosis FRC41 that was isolated from the inguinal lymph node of a 12-year-old girl with necrotizing lymphadenitis. To detect potential virulence factors and corresponding gene-regulatory networks in this human isolate, the genome sequence of C. pseudotuberculosis FCR41 was determined by pyrosequencing and functionally annotated. RESULTS Sequencing and assembly of the C. pseudotuberculosis FRC41 genome yielded a circular chromosome with a size of 2,337,913 bp and a mean G+C content of 52.2%. Specific gene sets associated with iron and zinc homeostasis were detected among the 2,110 predicted protein-coding regions and integrated into a gene-regulatory network that is linked with both the central metabolism and the oxidative stress response of FRC41. Two gene clusters encode proteins involved in the sortase-mediated polymerization of adhesive pili that can probably mediate the adherence to host tissue to facilitate additional ligand-receptor interactions and the delivery of virulence factors. The prominent virulence factors phospholipase D (Pld) and corynebacterial protease CP40 are encoded in the genome of this human isolate. The genome annotation revealed additional serine proteases, neuraminidase H, nitric oxide reductase, an invasion-associated protein, and acyl-CoA carboxylase subunits involved in mycolic acid biosynthesis as potential virulence factors. The cAMP-sensing transcription regulator GlxR plays a key role in controlling the expression of several genes contributing to virulence. CONCLUSION The functional data deduced from the genome sequencing and the extended knowledge of virulence factors indicate that the human isolate C. pseudotuberculosis FRC41 is equipped with a distinct gene set promoting its survival under unfavorable environmental conditions encountered in the mammalian host.
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Affiliation(s)
- Eva Trost
- Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Bielefeld, Germany
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Schliep K, Lopez P, Lapointe FJ, Bapteste E. Harvesting evolutionary signals in a forest of prokaryotic gene trees. Mol Biol Evol 2010; 28:1393-405. [PMID: 21172835 DOI: 10.1093/molbev/msq323] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phylogenomic studies produce increasingly large phylogenetic forests of trees with patchy taxonomical sampling. Typically, prokaryotic data generate thousands of gene trees of all sizes that are difficult, if not impossible, to root. Their topologies do not match the genealogy of lineages, as they are influenced not only by duplication, losses, and vertical descent but also by lateral gene transfer (LGT) and recombination. Because this complexity in part reflects the diversity of evolutionary processes, the study of phylogenetic forests is thus a great opportunity to improve our understanding of prokaryotic evolution. Here, we show how the rich evolutionary content of such novel phylogenetic objects can be exploited through the development of new approaches designed specifically for extracting the multiple evolutionary signals present in the forest of life, that is, by slicing up trees into remarkable bits and pieces: clans, slices, and clips. We harvested a forest of 6,901 unrooted gene trees comprising up to 100 prokaryotic genomes (41 archaea and 59 bacteria) to search for evolutionary events that a species tree would not account for. We identified 1) trees and partitions of trees that reflected the lifestyle of organisms rather than their taxonomy, 2) candidate lifestyle-specific genetic modules, used by distinct unrelated organisms to adapt to the same environment, 3) gene families, nonrandomly distributed in the functional space, that were frequently exchanged between archaea and bacteria, sometimes without major changes in their sequences. Finally, 4) we reconstructed polarized networks of genetic partnerships between archaea and bacteria to describe some of the rules affecting LGT between these two Domains.
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Affiliation(s)
- Klaus Schliep
- UMR CNRS 7138 Systématique, Adaptation, Evolution, Muséum National d'Histoire Naturelle, Paris, France
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14
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Torrents E, Sjöberg BM. Antibacterial activity of radical scavengers against class Ib ribonucleotide reductase from Bacillus anthracis. Biol Chem 2010; 391:229-234. [PMID: 20030587 DOI: 10.1515/bc.2010.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Bacillus anthracis is a severe mammalian pathogen. The deoxyribonucleotides necessary for DNA replication and repair are provided via the ribonucleotide reductase (RNR) enzyme. RNR is also important for spore germination and cell proliferation upon infection. We show that the expression of B. anthracis class Ib RNR responds to the environment that the pathogen encounters upon infection. We also show that several anti-proliferative agents (radical scavengers) specifically inhibit the B. anthracis RNR. Owing to the importance of RNR in the pathogenic infection process, our results highlight a promising potential to inhibit the growth of B. anthracis early during infection.
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Affiliation(s)
- Eduard Torrents
- Department of Molecular Biology and Functional Genomics, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-10691 Stockholm, Sweden
- Cellular Biotechnology, Institute for Bioengineering of Catalonia, Baldiri Reixac 15-21, E-08028 Barcelona, Spain
| | - Britt-Marie Sjöberg
- Department of Molecular Biology and Functional Genomics, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-10691 Stockholm, Sweden
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15
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Spinler JK, Zajdowicz SLW, Haller JC, Oram DM, Gill RE, Holmes RK. Development and use of a selectable, broad-host-range reporter transposon for identifying environmentally regulated promoters in bacteria. FEMS Microbiol Lett 2009; 291:143-50. [PMID: 19146571 DOI: 10.1111/j.1574-6968.2008.01430.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This report describes the development and use of TnKnXSp, a selectable broad-host-range reporter transposon with a promoterless aphA gene. Insertion of TnKnXSp into the chromosome of a kanamycin-susceptible bacterium confers resistance to kanamycin only if aphA is transcribed from an active promoter adjacent to the insertion site. We designed TnKnXSp as a tool for identifying environmentally regulated promoters in bacteria and developed general methods for initial characterization of any TnKnXSp integrant. To identify putative iron-regulated promoters in Corynebacterium diphtheriae, we constructed TnKnXSp integrants and identified a subgroup that expressed kanamycin resistance under low-iron, but not high-iron, conditions. We characterized representative integrants with this phenotype, located the TnKnXSp insertion in each, and demonstrated that transcription of aphA was repressed under high-iron vs. low-iron growth conditions. We also demonstrated that TnKnXSp can be used in bacteria other than C. diphtheriae, including Escherichia coli and Bacillus subtilis. Our findings validate TnKnXSp as a useful tool for identifying environmentally regulated promoters in bacteria.
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Affiliation(s)
- Jennifer K Spinler
- Department of Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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16
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Ranjan S, Yellaboina S, Ranjan A. IdeR in Mycobacteria: From Target Recognition to Physiological Function. Crit Rev Microbiol 2008; 32:69-75. [PMID: 16809230 DOI: 10.1080/10408410600709768] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In mycobacteria, iron dependent transcription regulator (IdeR) regulates transcription of genes in response to iron levels. The IdeR regulated genes have been investigated mostly in M. tuberculosis, M. smegmatis, and in few of the other related species. Recent advances in crystal structure solution and computational as well as experimental identification of IdeR targets has provided insight into IdeR structure and function. Here in this review we take stock of current state of knowledge on IdeR and its targets to understand the underlying design of the IdeR regulon and its role in mycobacterial physiology.
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Affiliation(s)
- Sarita Ranjan
- Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
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O'Neil RA, Holmes DE, Coppi MV, Adams LA, Larrahondo MJ, Ward JE, Nevin KP, Woodard TL, Vrionis HA, N'Guessan AL, Lovley DR. Gene transcript analysis of assimilatory iron limitation in Geobacteraceae during groundwater bioremediation. Environ Microbiol 2008; 10:1218-30. [PMID: 18279349 DOI: 10.1111/j.1462-2920.2007.01537.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Limitations on the availability of Fe(III) as an electron acceptor are thought to play an important role in restricting the growth and activity of Geobacter species during bioremediation of contaminated subsurface environments, but the possibility that these organisms might also be limited in the subsurface by the availability of iron for assimilatory purposes was not previously considered because copious quantities of Fe(II) are produced as the result of Fe(III) reduction. Analysis of multiple Geobacteraceae genomes revealed the presence of a three-gene cluster consisting of homologues of two iron-dependent regulators, fur and dtxR (ideR), separated by a homologue of feoB, which encodes an Fe(II) uptake protein. This cluster appears to be conserved among members of the Geobacteraceae and was detected in several environments. Expression of the fur-feoB-ideR cluster decreased as Fe(II) concentrations increased in chemostat cultures. The number of Geobacteraceae feoB transcripts in groundwater samples from a site undergoing in situ uranium bioremediation was relatively high until the concentration of dissolved Fe(II) increased near the end of the field experiment. These results suggest that, because much of the Fe(II) is sequestered in solid phases, Geobacter species, which have a high requirement for iron for iron-sulfur proteins, may be limited by the amount of iron available for assimilatory purposes. These results demonstrate the ability of transcript analysis to reveal previously unsuspected aspects of the in situ physiology of microorganisms in subsurface environments.
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Affiliation(s)
- Regina A O'Neil
- Department of Microbiology, 203 N Morrill Science Center IVN, University of Massachusetts at Amherst, Amherst, MA 01003, USA.
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Akhter Y, Yellaboina S, Farhana A, Ranjan A, Ahmed N, Hasnain SE. Genome scale portrait of cAMP-receptor protein (CRP) regulons in mycobacteria points to their role in pathogenesis. Gene 2007; 407:148-58. [PMID: 18022770 DOI: 10.1016/j.gene.2007.10.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 10/02/2007] [Accepted: 10/05/2007] [Indexed: 10/22/2022]
Abstract
cAMP Receptor Protein (CRP)/Fumarate Nitrate Reductase Regulator (FNR) family proteins are ubiquitous regulators of cell stress in eubacteria. These proteins are commonly associated with maintenance of intracellular oxygen levels, redox-state, oxidative and nitrosative stresses, and extreme temperature conditions by regulating expression of target genes that contain regulatory cognate DNA elements. We describe the use of informatics enabled comparative genomics to identify novel genes under the control of CRP regulator in Mycobacterium tuberculosis (M.tb). An inventory of CRP regulated genes and their operon context in important mycobacterial species such as M. leprae, M. avium subsp. paratuberculosis and M. smegmatis and several common genes within this genus including the important cellular functions, mainly, cell-wall biogenesis, cAMP signaling and metabolism associated with such regulons were identified. Our results provide a possible theoretical framework for better understanding of the stress response in mycobacteria. The conservation of the CRP regulated genes in pathogenic mycobacteria, as opposed to non-pathogenic ones, highlights the importance of CRP-regulated genes in pathogenesis.
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Affiliation(s)
- Yusuf Akhter
- Laboratory of Molecular and Cellular Biology, CDFD, Hyderabad, India
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Swaminathan A, Mandlik A, Swierczynski A, Gaspar A, Das A, Ton-That H. Housekeeping sortase facilitates the cell wall anchoring of pilus polymers in Corynebacterium diphtheriae. Mol Microbiol 2007; 66:961-74. [PMID: 17919283 DOI: 10.1111/j.1365-2958.2007.05968.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many surface proteins in Gram-positive bacteria are covalently linked to the cell wall through a transpeptidation reaction catalysed by the enzyme sortase. Corynebacterium diphtheriae encodes six sortases, five of which are devoted to the assembly of three distinct types of pilus fibres--SrtA for the SpaA-type pilus, SrtB/SrtC for the SpaD-type pilus, and SrtD/SrtE for the SpaH-type pilus. We demonstrate here the function of SrtF, the so-called housekeeping sortase, in the cell wall anchoring of pili. We show that a multiple deletion mutant strain expressing only SrtA secretes a large portion of SpaA polymers into the culture medium, with concomitant decrease in the cell wall-linked pili. The same phenotype is observed with the mutant that is missing SrtF alone. By contrast, a strain that expresses only SrtF displays surface-linked pilins but no polymers. Therefore, SrtF can catalyse the cell wall anchoring of pilin monomers as well as pili, but it does not polymerize pilins. We show that SrtA and SrtF together generate wild-type levels of the SpaA-type pilus on the bacterial surface. Furthermore, by regulating the expression of SpaA in the cell, we demonstrate that the SrtF function becomes critical when the SpaA level is sufficiently high. Together, these findings provide key evidence for a two-stage model of pilus assembly: pilins are first polymerized by a pilus-specific sortase, and the resulting fibre is then attached to the cell wall by either the cognate sortase or the housekeeping sortase.
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Affiliation(s)
- Anu Swaminathan
- Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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Ranjan S, Gundu RK, Ranjan A. MycoperonDB: a database of computationally identified operons and transcriptional units in Mycobacteria. BMC Bioinformatics 2006; 7 Suppl 5:S9. [PMID: 17254314 PMCID: PMC1764487 DOI: 10.1186/1471-2105-7-s5-s9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background A key post genomics challenge is to identify how genes in an organism come together and perform physiological functions. An important first step in this direction is to identify transcriptional units, operons and regulons in a genome. Here we implement and report a strategy to computationally identify transcriptional units and operons of mycobacteria and construct a database-MycoperonDB. Description We have predicted transcriptional units and operons in mycobacteria and organized these predictions in the form of relational database called MycoperonDB. MycoperonDB database at present consists of 18053 genes organized as 8256 predicted operons and transcriptional units from five closely related species of mycobacteria. The database further provides literature links for experimentally characterized operons. All known promoters and related information is collected, analysed and stored. It provides a user friendly interface to allow a web based navigation of transcription units and operons. The web interface provides search tools to locate transcription factor binding DNA motif upstream to various genes. The reliability of operon prediction has been assessed by comparing the predicted operons with a set of known operons. Conclusion MycoperonDB is a publicly available structured relational database which has information about mycobacterial genes, transcriptional units and operons. We expect this database to assist molecular biologists/microbiologists in general, to hypothesize functional linkages between operonic genes of mycobacteria, their experimental characterization and validation. The database is freely available from our website .
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Affiliation(s)
- Sarita Ranjan
- Computational & Functional Genomics Group, Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
| | - Ranjit Kumar Gundu
- Bioinformatics Group, Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
| | - Akash Ranjan
- Computational & Functional Genomics Group, Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
- Bioinformatics Group, Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
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Ranjan S, Seshadri J, Vindal V, Yellaboina S, Ranjan A. iCR: a web tool to identify conserved targets of a regulatory protein across the multiple related prokaryotic species. Nucleic Acids Res 2006; 34:W584-7. [PMID: 16845075 PMCID: PMC1538900 DOI: 10.1093/nar/gkl202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Gene regulatory circuits are often commonly shared between two closely related organisms. Our web tool iCR (identify Conserved target of a Regulon) makes use of this fact and identify conserved targets of a regulatory protein. iCR is a special refined extension of our previous tool PredictRegulon- that predicts genome wide, the potential binding sites and target operons of a regulatory protein in a single user selected genome. Like PredictRegulon, the iCR accepts known binding sites of a regulatory protein as ungapped multiple sequence alignment and provides the potential binding sites. However important differences are that the user can select more than one genome at a time and the output reports the genes that are common in two or more species. In order to achieve this, iCR makes use of Cluster of Orthologous Group (COG) indices for the genes. This tool analyses the upstream region of all user-selected prokaryote genome and gives the output based on conservation target orthologs. iCR also reports the Functional class codes based on COG classification for the encoded proteins of downstream genes which helps user understand the nature of the co-regulated genes at the result page itself. iCR is freely accessible at .
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Affiliation(s)
| | | | | | | | - Akash Ranjan
- To whom correspondence should be addressed. Tel: +91 40 27171442; Fax: +91 40 27171442;
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Yellaboina S, Ranjan S, Vindal V, Ranjan A. Comparative analysis of iron regulated genes in mycobacteria. FEBS Lett 2006; 580:2567-76. [PMID: 16631750 DOI: 10.1016/j.febslet.2006.03.090] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 03/20/2006] [Accepted: 03/28/2006] [Indexed: 11/22/2022]
Abstract
Iron dependent regulator, IdeR, regulates the expression of genes in response to intracellular iron levels in M. tuberculosis. Orthologs of IdeR are present in all the sequenced genomes of mycobacteria. We have used a computational approach to identify conserved IdeR regulated genes across the mycobacteria and the genes that are specific to each of the mycobacteria. Novel iron regulated genes that code for a predicted 4-hydroxy benzoyl coA hydrolase (Rv1847) and a protease dependent antibiotic regulatory system (Rv1846c, Rv0185c) are conserved across the mycobacteria. Although Mycobacterium natural-resistance-associated macrophage protein (Mramp) is present in all mycobacteria, it is, as predicted, an iron-regulated gene in only one species, M. avium subsp. paratuberculosis. We also observed an additional iron-regulated exochelin biosynthetic operon, which is present only in non-pathogenic Mycobacterium, M. smegmatis.
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Affiliation(s)
- Sailu Yellaboina
- Computational and Functional Genomics Group, Sun Centre of Excellence in Medical Bioinformatics, Centre for DNA Fingerprinting and Diagnostics, EMBnet India Node, Hyderabad 500076, India
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Prakash P, Yellaboina S, Ranjan A, Hasnain SE. Computational prediction and experimental verification of novel IdeR binding sites in the upstream sequences of Mycobacterium tuberculosis open reading frames. Bioinformatics 2005; 21:2161-6. [PMID: 15746274 DOI: 10.1093/bioinformatics/bti375] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IdeR (iron-dependent regulator) is a key regulator of virulence factors and iron acquisition systems in Mycobacterium tuberculosis. Despite the wealth of information available on IdeR-regulated genes of M.tuberculosis, there is still an underlying possibility that there are novel genes/pathways that have gone undetected, the identification of which could give new insights into understanding the pathogenesis of M.tuberculosis. We describe an in silico approach employing the positional relative entropy method to identify potential IdeR binding sites in the upstream sequences of all the 3919 ORFs of M.tuberculosis. While many of the predictions made by this approach overlapped with the ones already identified by microarray experiments and binding assays, pointing to the accuracy of our method, a few genes for which there has been no evidence for IdeR regulation were additionally identified. Our results have implications on the iron-dependent regulatory mechanism of M.tuberculosis vis-a-vis the activity of urease operon and novel transcription regulators and transporters.
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Affiliation(s)
- Prachee Prakash
- Laboratory of Molecular and Cellular Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500 076, India
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