1
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Zhou X, Chen D, Yu M, Jiao Y, Tao F. Role of Flavohemoglobins in the Development and Aflatoxin Biosynthesis of Aspergillus flavus. J Fungi (Basel) 2024; 10:437. [PMID: 38921422 PMCID: PMC11204391 DOI: 10.3390/jof10060437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/09/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Aspergillus flavus is notorious for contaminating food with its secondary metabolite-highly carcinogenic aflatoxins. In this study, we found that exogenous nitric oxide (NO) donor could influence aflatoxin production in A. flavus. Flavohemoglobins (FHbs) are vital functional units in maintaining nitric oxide (NO) homeostasis and are crucial for normal cell function. To investigate whether endogenous NO changes affect aflatoxin biosynthesis, two FHbs, FHbA and FHbB, were identified in this study. FHbA was confirmed as the main protein to maintain NO homeostasis, as its absence led to a significant increase in intracellular NO levels and heightened sensitivity to SNP stress. Dramatically, FHbA deletion retarded aflatoxin production. In addition, FHbA played important roles in mycelial growth, conidial germination, and sclerotial development, and response to oxidative stress and high-temperature stress. Although FHbB did not significantly impact the cellular NO level, it was also involved in sclerotial development, aflatoxin synthesis, and stress response. Our findings provide a new perspective for studying the regulatory mechanism of the development and secondary mechanism in A. flavus.
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Affiliation(s)
| | | | | | | | - Fang Tao
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China; (X.Z.); (D.C.); (M.Y.); (Y.J.)
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2
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Schuster CD, Salvatore F, Moens L, Martí MA. Globin phylogeny, evolution and function, the newest update. Proteins 2024; 92:720-734. [PMID: 38192262 DOI: 10.1002/prot.26659] [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: 09/06/2023] [Revised: 11/22/2023] [Accepted: 12/15/2023] [Indexed: 01/10/2024]
Abstract
Our globin census update allows us to refine our vision of globin origin, evolution, and structure to function relationship in the context of the currently accepted tree of life. The modern globin domain originates as a single domain, three-over-three α-helical folded structure before the diversification of the kingdoms of life (Bacteria, Archaea, Eukarya). Together with the diversification of prokaryotes, three monophyletic globin families (M, S, and T) emerged, most likely in Proteobacteria and Actinobacteria, displaying specific sequence and structural features, and spread by vertical and horizontal gene transfer, most probably already present in the last universal common ancestor (LUCA). Non-globin domains were added, and eventually lost again, creating multi-domain structures in key branches of M- (FHb and Adgb) and the vast majority of S globins, which with their coevolved multi-domain architectures, have predominantly "sensor" functions. Single domain T-family globins diverged into four major groups and most likely display functions related to reactive nitrogen and oxygen species (RNOS) chemistry, as well as oxygen storage/transport which drives the evolution of its major branches with their characteristic key distal residues (B10, E11, E7, and G8). M-family evolution also lead to distinctive major types (FHb and Fgb, Ngb, Adgb, GbX vertebrate Gbs), and shows the shift from high oxygen affinity controlled by TyrB10-Gln/AsnE11 likely related to RNOS chemistry in microorganisms, to a moderate oxygen affinity storage/transport function controlled by hydrophobic B10/E11-HisE7 in multicellular animals.
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Affiliation(s)
- Claudio David Schuster
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Franco Salvatore
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Luc Moens
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Marcelo Adrián Martí
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET, Ciudad Autónoma de Buenos Aires, Argentina
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3
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Masse MM, Guzman-Luna V, Varela AE, Mahfuza Shapla U, Hutchinson RB, Srivastava A, Wei W, Fuchs AM, Cavagnero S. Nascent chains derived from a foldable protein sequence interact with specific ribosomal surface sites near the exit tunnel. Sci Rep 2024; 14:12324. [PMID: 38811604 PMCID: PMC11137106 DOI: 10.1038/s41598-024-61274-1] [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: 03/25/2023] [Accepted: 05/03/2024] [Indexed: 05/31/2024] Open
Abstract
In order to become bioactive, proteins must be translated and protected from aggregation during biosynthesis. The ribosome and molecular chaperones play a key role in this process. Ribosome-bound nascent chains (RNCs) of intrinsically disordered proteins and RNCs bearing a signal/arrest sequence are known to interact with ribosomal proteins. However, in the case of RNCs bearing foldable protein sequences, not much information is available on these interactions. Here, via a combination of chemical crosslinking and time-resolved fluorescence-anisotropy, we find that nascent chains of the foldable globin apoHmp1-140 interact with ribosomal protein L23 and have a freely-tumbling non-interacting N-terminal compact region comprising 63-94 residues. Longer RNCs (apoHmp1-189) also interact with an additional yet unidentified ribosomal protein, as well as with chaperones. Surprisingly, the apparent strength of RNC/r-protein interactions does not depend on nascent-chain sequence. Overall, foldable nascent chains establish and expand interactions with selected ribosomal proteins and chaperones, as they get longer. These data are significant because they reveal the interplay between independent conformational sampling and nascent-protein interactions with the ribosomal surface.
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Affiliation(s)
- Meranda M Masse
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Valeria Guzman-Luna
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Angela E Varela
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Ummay Mahfuza Shapla
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Rachel B Hutchinson
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Food Science, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Aniruddha Srivastava
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- McGaw Medical Center, Northwestern University, Chicago, IL, 60611, USA
| | - Wanting Wei
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- AIDS Vaccine Research Laboratory, University of Wisconsin-Madison, Madison, WI, 53711, USA
| | - Andrew M Fuchs
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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4
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Das S, Kumar P. Exploring the carbonic anhydrase-mimetic [(PMDTA) 2ZnII2(OH -) 2] 2+ for nitric oxide monooxygenation. Dalton Trans 2024; 53:6173-6177. [PMID: 38501600 DOI: 10.1039/d4dt00407h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
In biology, nitrite (NO2-) serves as a storage pool of nitric oxide (NO); however, the formation of NO2- from NO is still under investigation. Here, we report the NO monooxygenation (NOM) reaction of a ZnII-hydroxide complex (1), producing a ZnII-nitrito complex {2, (ZnII-NO2-)} + H2.
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Affiliation(s)
- Sandip Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
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5
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Park HJ, Jeong HW, Lee C, Lee MR, Choi H, Kim E, Bang IS. Val43 residue of NsrR is crucial for the nitric oxide response of Salmonella Typhimurium. Microbiol Spectr 2024; 12:e0302423. [PMID: 38054720 PMCID: PMC10783083 DOI: 10.1128/spectrum.03024-23] [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: 10/02/2023] [Accepted: 10/30/2023] [Indexed: 12/07/2023] Open
Abstract
ABSTRACT In pathogenic bacteria, the flavohemoglobin Hmp is crucial in metabolizing the cytotoxic levels of nitric oxide (NO) produced in phagocytic cells, contributing to bacterial virulence. Hmp expression is predominantly regulated by the Rrf2 family transcription repressor NsrR in an NO-dependent manner; however, the underlying molecular mechanism in enterobacteria remains poorly understood. In this study, we identified Val43 of Salmonella Typhimurium NsrR (StNsrR) as a critical amino acid residue for regulating Hmp expression. The Val43-to-Ala-substituted mutant NsrR isolated through random and site-directed mutagenesis showed high binding affinity to the target DNA irrespective of NO exposure, resulting in a severe reduction in hmp transcription and slow NO metabolism in Salmonella under NO-producing conditions. Conversely, the Val43-to-Glu-substituted NsrR caused effects similar to nsrR null mutation, which directed hmp transcription and NO metabolism in a constitutive way. Comparative analysis of the primary sequences of NsrR and another NO-sensing Rrf2 family regulator, IscR, from diverse bacteria, revealed that Val43 of enterobacterial NsrR corresponds to Ala in Pseudomonas aeruginosa or Streptomyces coelicolor NsrR and Glu in enterobacterial IscR, all of which are located in the DNA recognition helix α3. The predicted structure of StNsrR in complex with the hmp DNA suggests dissimilar spatial stoichiometry in the interactions of Val43 and its substituted residues with the target DNA, consistent with the observed phenotypic changes in StNsrR Val43 mutants. Our findings highlight the discriminative roles of the NsrR recognition helix in regulating species-specific target gene expression, facilitating effective NO detoxification strategies in bacteria across diverse environments. IMPORTANCE The precise regulation of flavohemoglobin Hmp expression by NsrR is critical for bacterial fitness, as excessive Hmp expression in the absence of NO can disturb bacterial redox homeostasis. While the molecular structure of Streptomyces coelicolor NsrR has been recently identified, the specific molecular structures of NsrR proteins in enterobacteria remain unknown. Our discovery of the crucial role of Val43 in the DNA recognition helix α3 of Salmonella NsrR offers valuable insights into the Hmp modulation under NO stress. Furthermore, the observed amino acid polymorphisms in the α3 helices of NsrR proteins across different bacterial species suggest the diverse evolution of NsrR structure and gene regulation in response to varying levels of NO pressure within their ecological niches.
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Affiliation(s)
- Hee Jeong Park
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, Republic of Korea
| | - Hye Won Jeong
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, Republic of Korea
| | - Choa Lee
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, Republic of Korea
| | - Mi Rae Lee
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, Republic of Korea
| | - Hojung Choi
- Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Eungseok Kim
- Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Iel Soo Bang
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, Republic of Korea
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Amahisa M, Tsukagoshi M, Kadooka C, Masuo S, Takeshita N, Doi Y, Takagi H, Takaya N. The Metabolic Regulation of Amino Acid Synthesis Counteracts Reactive Nitrogen Stress via Aspergillus nidulans Cross-Pathway Control. J Fungi (Basel) 2024; 10:58. [PMID: 38248967 PMCID: PMC10817288 DOI: 10.3390/jof10010058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/23/2024] Open
Abstract
Nitric oxide (NO) is a natural reactive nitrogen species (RNS) that alters proteins, DNA, and lipids and damages biological activities. Although microorganisms respond to and detoxify NO, the regulation of the cellular metabolic mechanisms that cause cells to tolerate RNS toxicity is not completely understood. We found that the proline and arginine auxotrophic proA5 and argB2 mutants of the fungus Aspergillus nidulans require more arginine and proline for normal growth under RNS stress that starves cells by accumulating fewer amino acids. Fungal transcriptomes indicated that RNS stress upregulates the expression of the biosynthetic genes required for global amino acids, including proline and arginine. A mutant of the gene disruptant, cpcA, which encodes the transcriptional regulation of the cross-pathway control of general amino acid synthesis, did not induce these genes, and cells accumulated fewer amino acids under RNS stress. These results indicated a novel function of CpcA in the cellular response to RNS stress, which is mediated through amino acid starvation and induces the transcription of genes for general amino acid synthesis. Since CpcA also controls organic acid biosynthesis, impaired intermediates of such biosynthesis might starve cells of amino acids. These findings revealed the importance of the mechanism regulating amino acid homeostasis for fungal responses to and survival under RNS stress.
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Affiliation(s)
- Madoka Amahisa
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Madoka Tsukagoshi
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Chihiro Kadooka
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Shunsuke Masuo
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Norio Takeshita
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Yuki Doi
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
| | - Hiroshi Takagi
- Institute for Research Initiatives, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan;
| | - Naoki Takaya
- Microbiology Research Center for Sustainability, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; (M.A.); (C.K.); (S.M.); (N.T.); (Y.D.)
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7
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Yang Q, Ran Y, Guo S, Li F, Xiang D, Cao Y, Qiao D, Xu H, Cao Y. Molecular characterization and expression profiling of two flavohemoglobin genes play essential roles in dissolved oxygen and NO stress in Saitozyma podzolica zwy2-3. Int J Biol Macromol 2023; 253:127008. [PMID: 37844810 DOI: 10.1016/j.ijbiomac.2023.127008] [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: 04/19/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 10/18/2023]
Abstract
Flavohemoglobins (Fhbs) are key enzymes involved in microbial nitrosative stress resistance and nitric oxide degradation. However, the roles of Fhbs in fungi remain largely unknown. In this study, SpFhb1 and SpFhb2, two flavohemoglobin-encoding genes in Saitozyma podzolica zwy2-3 were characterized. Protein structure analysis and molecular docking showed that SpFhbs were conserved in bacteria and fungi. Phylogenetic analysis revealed that SpFhb2 may be acquired through the transfer event of independent horizontal genes from bacteria. The expression levels of SpFhb1 and SpFhb2 showed opposite trend under high/low dissolved oxygen, implying that they may exhibited different functions. Through deletion and overexpression of SpFhbs, we confirmed that SpFhbs were conducive to lipid accumulation under high stress. The sensitivities of ΔFhb mutants to NO stress were significantly increased compared with that in the WT, indicating that they were required for NO detoxification and nitrosative stress resistance in S. podzolica zwy2-3. Furthermore, SpAsg1 was identified that simultaneously regulates SpFhbs, which functions in the lipid accumulation under high/low dissolved oxygen and NO stress in S. podzolica zwy2-3. Overall, two different SpFhbs were identified in this study, providing new insights into the mechanism of lipid accumulation in fungi under high/low dissolved oxygen and NO stress.
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Affiliation(s)
- Qingzhuoma Yang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yulu Ran
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Shengtao Guo
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Fazhi Li
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Dongyou Xiang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yu Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Dairong Qiao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China
| | - Hui Xu
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yi Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, Sichuan 610065, China.
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8
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C S AK, Das S, Kulbir, Bhardwaj P, Sk MP, Kumar P. Mechanistic insights into nitric oxide oxygenation (NOO) reactions of {CrNO} 5 and {CoNO} 8. Dalton Trans 2023; 52:16492-16499. [PMID: 37874255 DOI: 10.1039/d3dt03177b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Here, we report the nitric oxide oxygenation (NOO) reactions of two distinct metal nitrosyls {Co-nitrosyl (S = 0) vs. Cr-nitrosyl (S = 1/2)}. In this regard, we synthesized and characterized [(BPMEN)Co(NO)]2+ ({CoNO}8, 1) to compare its NOO reaction with that of [(BPMEN)Cr(NO)(Cl-)]+ ({CrNO}5, 2), having a similar ligand framework. Kinetic measurements showed that {CrNO}5 is thermally more stable than {CoNO}8. Complexes 1 and 2, upon reaction with the superoxide anion (O2˙-), generate [(BPMEN)CoII(NO2-)2] (CoII-NO2-, 3) and [(BPMEN)CrIII(NO2-)Cl-]+ (CrIII-NO2-, 4), respectively, with O2 evolution. Furthermore, analysis of these NOO reactions and tracking of the N-atom using 15N-labeled NO (15NO) revealed that the N-atoms of 3 (CoII-15NO2-) and 4 (CrIII-15NO2-) derive from the nitrosyl (15NO) moieties of 1 and 2, respectively. This work represents a comparative study of oxidation reactions of {CoNO}8vs. {CrNO}5, showing different rates of the NOO reactions due to different thermal stability. To complete the NOM cycle, we reacted 3 and 4 with NO, and surprisingly, only 3 generated {CoNO}8 species, while 4 was unreactive towards NO. Furthermore, the phenol ring nitration test, performed using 2,4-di-tert-butylphenol (2,4-DTBP), suggested the presence of a proposed peroxynitrite (PN) intermediate in the NOO reactions of 1 and 2.
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Affiliation(s)
- Akshaya Keerthi C S
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Sandip Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Kulbir
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Prabhakar Bhardwaj
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Md Palashuddin Sk
- Department of Chemistry, Aligarh Muslim University (AMU) Aligarh, Uttar Pradesh 202001, India
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
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9
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Gardner AM, Gardner PR. Dioxygen and glucose force motion of the electron-transfer switch in the iron(III) flavohemoglobin-type nitric oxide dioxygenase. J Inorg Biochem 2023; 245:112257. [PMID: 37229820 DOI: 10.1016/j.jinorgbio.2023.112257] [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: 12/18/2022] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023]
Abstract
Kinetic and structural investigations of the flavohemoglobin-type NO dioxygenase have suggested critical roles for transient Fe(III)O2 complex formation and O2-forced movements affecting hydride transfer to the FAD cofactor and electron-transfer to the Fe(III)O2 complex. Stark-effect theory together with structural models and dipole and internal electrostatic field determinations provided a semi-quantitative spectroscopic method for investigating the proposed Fe(III)O2 complex and O2-forced movements. Deoxygenation of the enzyme causes Stark effects on the ferric heme Soret and charge-transfer bands revealing the Fe(III)O2 complex. Deoxygenation also elicits Stark effects on the FAD that expose forces and motions that create a more restricted NADH access to FAD for hydride transfer and switch electron-transfer off. Glucose also forces the enzyme toward an off state. Amino acid substitutions at the B10, E7, E11, G8, D5, and F7 positions influence the Stark effects of O2 on resting heme spin states and FAD consistent with the proposed roles of the side chains in the enzyme mechanism. Deoxygenation of ferric myoglobin and hemoglobin A also induces Stark effects on the hemes suggesting a common 'oxy-met' state. The ferric myoglobin and hemoglobin heme spectra are also glucose-responsive. A conserved glucose or glucose-6-phosphate binding site is found bridging the BC-corner and G-helix in flavohemoglobin and myoglobin suggesting novel allosteric effector roles for glucose or glucose-6-phosphate in the NO dioxygenase and O2 storage functions. The results support the proposed roles of a ferric O2 intermediate and protein motions in regulating electron-transfer during NO dioxygenase turnover.
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Affiliation(s)
- Anne M Gardner
- Research and Development Division, Miami Valley Biotech, Suite 2445, 1001 E. 2(nd) Street, Dayton, OH 45402, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, R033, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
| | - Paul R Gardner
- Research and Development Division, Miami Valley Biotech, Suite 2445, 1001 E. 2(nd) Street, Dayton, OH 45402, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, R033, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Chemistry and Biochemistry Department, University of Dayton, 300 College Park, Dayton, OH 45469, USA.
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10
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Hirose S, Hesnard J, Ghazi N, Roussel D, Voituron Y, Cochet-Escartin O, Rieu JP, Anjard C, Funamoto K. The aerotaxis of Dictyostelium discoideum is independent of mitochondria, nitric oxide and oxidative stress. Front Cell Dev Biol 2023; 11:1134011. [PMID: 37397260 PMCID: PMC10307954 DOI: 10.3389/fcell.2023.1134011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 05/22/2023] [Indexed: 07/04/2023] Open
Abstract
Spatial and temporal variations of oxygen environments affect the behaviors of various cells and are involved in physiological and pathological events. Our previous studies with Dictyostelium discoideum as a model of cell motility have demonstrated that aerotaxis toward an oxygen-rich region occurs below 2% O2. However, while the aerotaxis of Dictyostelium seems to be an effective strategy to search for what is essential for survival, the mechanism underlying this phenomenon is still largely unclear. One hypothesis is that an oxygen concentration gradient generates a secondary oxidative stress gradient that would direct cell migration towards higher oxygen concentration. Such mechanism was inferred but not fully demonstrated to explain the aerotaxis of human tumor cells. Here, we investigated the role on aerotaxis of flavohemoglobins, proteins that can both act as potential oxygen sensors and modulators of nitric oxide and oxidative stress. The migratory behaviors of Dictyostelium cells were observed under both self-generated and imposed oxygen gradients. Furthermore, their changes by chemicals generating or preventing oxidative stress were tested. The trajectories of the cells were then analyzed through time-lapse phase-contrast microscopic images. The results indicate that both oxidative and nitrosative stresses are not involved in the aerotaxis of Dictyostelium but cause cytotoxic effects that are enhanced upon hypoxia.
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Affiliation(s)
- Satomi Hirose
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Julie Hesnard
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | - Nasser Ghazi
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | - Damien Roussel
- LEHNA, UMR CNRS 5023, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Yann Voituron
- LEHNA, UMR CNRS 5023, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Oliver Cochet-Escartin
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | - Jean-Paul Rieu
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | - Christophe Anjard
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | - Kenichi Funamoto
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
- Institute of Fluid Science, Tohoku University, Sendai, Japan
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11
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Barnum TP, Coates JD. Chlorine redox chemistry is widespread in microbiology. THE ISME JOURNAL 2023; 17:70-83. [PMID: 36202926 PMCID: PMC9751292 DOI: 10.1038/s41396-022-01317-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 11/07/2022]
Abstract
Chlorine is abundant in cells and biomolecules, yet the biology of chlorine oxidation and reduction is poorly understood. Some bacteria encode the enzyme chlorite dismutase (Cld), which detoxifies chlorite (ClO2-) by converting it to chloride (Cl-) and molecular oxygen (O2). Cld is highly specific for chlorite and aside from low hydrogen peroxide activity has no known alternative substrate. Here, we reasoned that because chlorite is an intermediate oxidation state of chlorine, Cld can be used as a biomarker for oxidized chlorine species. Cld was abundant in metagenomes from various terrestrial habitats. About 5% of bacterial and archaeal genera contain a microorganism encoding Cld in its genome, and within some genera Cld is highly conserved. Cld has been subjected to extensive horizontal gene transfer. Genes found to have a genetic association with Cld include known genes for responding to reactive chlorine species and uncharacterized genes for transporters, regulatory elements, and putative oxidoreductases that present targets for future research. Cld was repeatedly co-located in genomes with genes for enzymes that can inadvertently reduce perchlorate (ClO4-) or chlorate (ClO3-), indicating that in situ (per)chlorate reduction does not only occur through specialized anaerobic respiratory metabolisms. The presence of Cld in genomes of obligate aerobes without such enzymes suggested that chlorite, like hypochlorous acid (HOCl), might be formed by oxidative processes within natural habitats. In summary, the comparative genomics of Cld has provided an atlas for a deeper understanding of chlorine oxidation and reduction reactions that are an underrecognized feature of biology.
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Affiliation(s)
- Tyler P Barnum
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - John D Coates
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA.
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12
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Grabacka M, Płonka PM, Pierzchalska M. The PPARα Regulation of the Gut Physiology in Regard to Interaction with Microbiota, Intestinal Immunity, Metabolism, and Permeability. Int J Mol Sci 2022; 23:ijms232214156. [PMID: 36430628 PMCID: PMC9696208 DOI: 10.3390/ijms232214156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
Peroxisome proliferator-activated receptor alpha (PPARα) is expressed throughout the mammalian gut: in epithelial cells, in the villi of enterocytes and in Paneth cells of intestinal crypts, as well as in some immune cells (e.g., lamina propria macrophages, dendritic cells) of the mucosa. This review examines the reciprocal interaction between PPARα activation and intestinal microbiota. We refer to the published data confirming that microbiota products can influence PPARα signaling and, on the other hand, PPARα activation is able to affect microbiota profile, viability, and diversity. PPARα impact on the broad spectrum of events connected to metabolism, signaling (e.g., NO production), immunological tolerance to dietary antigens, immunity and permeability of the gut are also discussed. We believe that the phenomena described here play a prominent role in gut homeostasis. Therefore, in conclusion we propose future directions for research, including the application of synthetic activators and natural endogenous ligands of PPARα (i.e., endocannabinoids) as therapeutics for intestinal pathologies and systemic diseases assumed to be related to gut dysbiosis.
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Affiliation(s)
- Maja Grabacka
- Department of Biotechnology and General Technology of Foods, Faculty of Food Technology, University of Agriculture, ul. Balicka 122, 30-149 Cracow, Poland
- Correspondence: ; Tel.: +48-12-662-4701
| | - Przemysław M. Płonka
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, ul. Gronostajowa 7, 30-387 Cracow, Poland
| | - Małgorzata Pierzchalska
- Department of Biotechnology and General Technology of Foods, Faculty of Food Technology, University of Agriculture, ul. Balicka 122, 30-149 Cracow, Poland
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13
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A Plasma-Based Decontamination Process Reveals Potential for an in-Process Surface-Sanitation Method. PLASMA 2022. [DOI: 10.3390/plasma5030027] [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
Methods, which use an indirect plasma treatment for the inactivation of microorganisms in foods, claim a vastly growing field of research. This paper presents a method that uses plasma-processed air (PPA) as a sanitizer. In addition to a sanitation concept for the decontamination of produce in the value chain, the presented method offers a possible application as an “in-process” surface sanitation. PPA provides antimicrobial-potent species, which are predominantly reactive nitrogen species (RNS); this has an outstanding groove penetration property. In an experimental approach, surfaces, made from materials, which are frequently used for the construction of food-processing plants, were inoculated with different microorganisms. Listeria monocytogenes (ATCC 15313), Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 10538), Salmonella enterica subsp. enterica serovar Typhimurium (ATCC 43971), and Salmonella enterica subsp. enterica serovar Enteritidis (ATCC 13076) are all microorganisms that frequently appear in foods and possess the risk for cross-contamination from the plant to the produce or vice versa. The contaminated samples were treated for various treatment times (1–5 min) with PPA of different antimicrobial potencies. Subsequently, the microbial load on the specimens was determined and compared with the load of untreated samples. As a result, reduction factors (RF) up to several log10-steps were obtained. Although surface and the bacterial strain showed an influence on the RF, the major influence was seen by a prolongation of the treatment time and an increase in the potency of the PPA.
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14
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Maiti BK. Cross‐talk Between (Hydrogen)Sulfite and Metalloproteins: Impact on Human Health. Chemistry 2022; 28:e202104342. [DOI: 10.1002/chem.202104342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Indexed: 12/28/2022]
Affiliation(s)
- Biplab K Maiti
- Department of Chemistry National Institute of Technology Sikkim, Ravangla Campus Barfung Block, Ravangla Sub Division South Sikkim 737139 India
- Department of Chemistry Cluster University of Jammu Canal Road Jammu 180001
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15
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Defenses of multidrug resistant pathogens against reactive nitrogen species produced in infected hosts. Adv Microb Physiol 2022; 80:85-155. [PMID: 35489794 DOI: 10.1016/bs.ampbs.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacterial pathogens have sophisticated systems that allow them to survive in hosts in which innate immunity is the frontline of defense. One of the substances produced by infected hosts is nitric oxide (NO) that together with its derived species leads to the so-called nitrosative stress, which has antimicrobial properties. In this review, we summarize the current knowledge on targets and protective systems that bacteria have to survive host-generated nitrosative stress. We focus on bacterial pathogens that pose serious health concerns due to the growing increase in resistance to currently available antimicrobials. We describe the role of nitrosative stress as a weapon for pathogen eradication, the detoxification enzymes, protein/DNA repair systems and metabolic strategies that contribute to limiting NO damage and ultimately allow survival of the pathogen in the host. Additionally, this systematization highlights the lack of available data for some of the most important human pathogens, a gap that urgently needs to be addressed.
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NorA, HmpX, and NorB Cooperate to Reduce NO Toxicity during Denitrification and Plant Pathogenesis in Ralstonia solanacearum. Microbiol Spectr 2022; 10:e0026422. [PMID: 35377234 PMCID: PMC9045102 DOI: 10.1128/spectrum.00264-22] [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] [Indexed: 12/14/2022] Open
Abstract
Ralstonia solanacearum, which causes bacterial wilt disease of many crops, requires denitrifying respiration to survive in its plant host. In the hypoxic environment of plant xylem vessels, this pathogen confronts toxic oxidative radicals like nitric oxide (NO), which is generated by both bacterial denitrification and host defenses. R. solanacearum has multiple distinct mechanisms that could mitigate this stress, including putative NO-binding protein (NorA), nitric oxide reductase (NorB), and flavohaemoglobin (HmpX). During denitrification and tomato pathogenesis and in response to exogenous NO, R. solanacearum upregulated norA, norB, and hmpX. Single mutants lacking ΔnorB, ΔnorA, or ΔhmpX increased expression of many iron and sulfur metabolism genes, suggesting that the loss of even one NO detoxification system demands metabolic compensation. Single mutants suffered only moderate fitness reductions in host plants, possibly because they upregulated their remaining protective genes. However, ΔnorA/norB, ΔnorB/hmpX, and ΔnorA/hmpX double mutants grew poorly in denitrifying culture and in planta. It is likely that the loss of norA, norB, and hmpX is lethal, since the methods used to construct the double mutants could not generate a triple mutant. Functional aconitase activity assays showed that NorA, HmpX, and especially NorB are important for maintaining iron-sulfur cluster proteins. Additionally, plant defense genes were upregulated in tomatoes infected with the NO-overproducing ΔnorB mutant, suggesting that bacterial detoxification of NO reduces the ability of the plant host to perceive the presence of the pathogen. Thus, R. solanacearum's three NO detoxification systems each contribute to and are collectively essential for overcoming metabolic nitrosative stress during denitrification, for virulence and growth in the tomato, and for evading host plant defenses. IMPORTANCE The soilborne plant pathogen Ralstonia solanacearum (Rs) causes bacterial wilt, a serious and widespread threat to global food security. Rs is metabolically adapted to low-oxygen conditions, using denitrifying respiration to survive in the host and cause disease. However, bacterial denitrification and host defenses generate nitric oxide (NO), which is toxic and also alters signaling pathways in both the pathogen and its plant hosts. Rs mitigates NO with a trio of mechanistically distinct proteins: NO-reductase (NorB), predicted iron-binding (NorA), and oxidoreductase (HmpX). This redundancy, together with analysis of mutants and in-planta dual transcriptomes, indicates that maintaining low NO levels is integral to Rs fitness in tomatoes (because NO damages iron-cluster proteins) and to evading host recognition (because bacterially produced NO can trigger plant defenses).
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Correa-Aragunde N, Nejamkin A, Del Castello F, Foresi N, Lamattina L. Nitric oxide synthases from photosynthetic organisms improve growth and confer nitrosative stress tolerance in E. coli. Insights on the pterin cofactor. Nitric Oxide 2022; 119:41-49. [PMID: 34942379 DOI: 10.1016/j.niox.2021.12.005] [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: 05/04/2021] [Revised: 12/01/2021] [Accepted: 12/17/2021] [Indexed: 11/28/2022]
Abstract
Nitric oxide synthase (NOS) catalyzes NO formation from the substrate l-arginine (Arg). Previously, NOS with distinct biochemical properties were characterized from two photosynthetic microorganisms, the unicellular algae Ostreococcus tauri (OtNOS) and the cyanobacteria Synechococcus PCC 7335 (SyNOS). In this work we studied the effect of recombinant OtNOS and SyNOS expressed under IPTG-induced promoter in E. coli, a bacterium that lacks NOS. Results show that OtNOS and SyNOS expression promote E. coli growth in a nutrient replete medium and allow to better metabolize Arg as N source. In LB medium, OtNOS induces the expression of the NO dioxygenase hmp in E. coli, in accordance with high NO levels visualized with the probe DAF-FM DA. In contrast, SyNOS expression does not induce hmp and show a slight increase of NO production compared to OtNOS. NOS expression reduces ROS production and increases viability of E. coli cultures growing in LB. A strong nitrosative stress provoked by the addition of 1 mM of the NO donors sodium nitroprusside (SNP) and nitrosoglutathione (GSNO) inhibits bacterial growth rate. Under these conditions, the expression of OtNOS or SyNOS counteracts NO donor toxicity restoring bacterial growth. Finally, using bioinformatic tools and ligand docking analyses, we postulate that tetrahydromonapterin (MH4), an endogenous pterin found in E. coli, could act as cofactor required for NOS catalytic activity. Our findings could be useful for the development of biotechnological applications using NOS expression to improve growth in NOS-lacking bacteria.
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Affiliation(s)
- Natalia Correa-Aragunde
- Instituto de Investigaciones Biológicas-CONICET, Universidad Nacional de Mar del Plata, CC1245, Mar del Plata, Argentina.
| | - Andrés Nejamkin
- Instituto de Investigaciones Biológicas-CONICET, Universidad Nacional de Mar del Plata, CC1245, Mar del Plata, Argentina
| | - Fiorella Del Castello
- Instituto de Investigaciones Biológicas-CONICET, Universidad Nacional de Mar del Plata, CC1245, Mar del Plata, Argentina
| | - Noelia Foresi
- Instituto de Investigaciones Biológicas-CONICET, Universidad Nacional de Mar del Plata, CC1245, Mar del Plata, Argentina
| | - Lorenzo Lamattina
- Instituto de Investigaciones Biológicas-CONICET, Universidad Nacional de Mar del Plata, CC1245, Mar del Plata, Argentina.
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18
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OUP accepted manuscript. FEMS Microbiol Lett 2022; 369:6544667. [DOI: 10.1093/femsle/fnab162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
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19
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Gardner PR. Ordered Motions in the Nitric-Oxide Dioxygenase Mechanism of Flavohemoglobin and Assorted Globins with Tightly Coupled Reductases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1414:45-96. [PMID: 36520413 DOI: 10.1007/5584_2022_751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nitric-oxide dioxygenases (NODs) activate and combine O2 with NO to form nitrate. A variety of oxygen-binding hemoglobins with associated partner reductases or electron donors function as enzymatic NODs. Kinetic and structural investigations of the archetypal two-domain microbial flavohemoglobin-NOD have illuminated an allosteric mechanism that employs selective tunnels for O2 and NO, gates for NO and nitrate, transient O2 association with ferric heme, and an O2 and NO-triggered, ferric heme spin crossover-driven, motion-controlled, and dipole-regulated electron-transfer switch. The proposed mechanism facilitates radical-radical coupling of ferric-superoxide with NO to form nitrate while preventing suicidal ferrous-NO formation. Diverse globins display the structural and functional motifs necessary for a similar allosteric NOD mechanism. In silico docking simulations reveal monomeric erythrocyte hemoglobin alpha-chain and beta-chain intrinsically matched and tightly coupled with NADH-cytochrome b5 oxidoreductase and NADPH-cytochrome P450 oxidoreductase, respectively, forming membrane-bound flavohemoglobin-like mammalian NODs. The neuroprotective neuroglobin manifests a potential NOD role in a close-fitting ternary complex with membrane-bound NADH-cytochrome b5 oxidoreductase and cytochrome b5. Cytoglobin interfaces weakly with cytochrome b5 for O2 and NO-regulated electron-transfer and coupled NOD activity. The mechanistic model also provides insight into the evolution of O2 binding cooperativity in hemoglobin and a basis for the discovery of allosteric NOD inhibitors.
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20
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Kim SH, Yang D, Bae YA. Hypoxic and nitrosative stress conditions modulate expression of myoglobin genes in a carcinogenic hepatobiliary trematode, Clonorchis sinensis. PLoS Negl Trop Dis 2021; 15:e0009811. [PMID: 34591853 PMCID: PMC8483323 DOI: 10.1371/journal.pntd.0009811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 09/13/2021] [Indexed: 11/18/2022] Open
Abstract
Despite recent evidence suggesting that adult trematodes require oxygen for the generation of bioenergy and eggshells, information on the molecular mechanism by which the parasites acquire oxygen remains largely elusive. In this study, the structural and expressional features of globin genes identified in Clonorchis sinensis, a carcinogenic trematode parasite that invades the hypoxic biliary tracts of mammalian hosts, were investigated to gain insight into the molecules that enable oxygen metabolism. The number of globin paralogs substantially differed among parasitic platyhelminths, ranging from one to five genes, and the C. sinensis genome encoded at least five globin genes. The expression of these Clonorchis genes, named CsMb (CsMb1—CsMb3), CsNgb, and CsGbX, according to their preferential similarity patterns toward respective globin subfamilies, exponentially increased in the worms coinciding with their sexual maturation, after being downregulated in early juveniles compared to those in metacercariae. The CsMb1 protein was detected throughout the parenchymal region of adult worms as well as in excretory-secretory products, whereas the other proteins were localized exclusively in the sexual organs and intrauterine eggs. Stimuli generated by exogenous oxygen, nitric oxide (NO), and nitrite as well as co-incubation with human cholangiocytes variously affected globin gene expression in live C. sinensis adults. Together with the specific histological distributions, these hypoxia-induced patterns may suggest that oxygen molecules transported by CsMb1 from host environments are provided to cells in the parenchyma and intrauterine eggs/sex organs of the worms for energy metabolism and/or, more importantly, eggshell formation by CsMb1 and CsMb3, respectively. Other globin homologs are likely to perform non-respiratory functions. Based on the responsive expression profile against nitrosative stress, an oxygenated form of secreted CsMb1 is suggested to play a pivotal role in parasite survival by scavenging NO generated by host immune cells via its NO dioxygenase activity. Trematode parasites that invade mammalian tissues have long been believed to produce bioenergy via anaerobic respiration in their definitive hosts. However, recent studies have revealed that these parasites require considerable amounts of oxygen for the generation of hard eggshells during sexual reproduction as well as energy metabolism. Despite these findings, information on the biological mechanisms and relevant molecules responsible for oxygen uptake in the host environment remains largely elusive. Clonorchis sinensis is a carcinogenic trematode parasite that causes clonorchiasis in humans by infecting the bile ducts. Here, we investigated globin genes/proteins in the liver fluke. The genome of C. sinensis encoded at least five globin paralogs (CsMb1, CsMb2, CsMb3, CsNgb, and CsGbX). Temporal expression of these globin genes coincided with the sexual maturation of C. sinensis. Based on the histological localities and induction profiles upon hypoxia, it could be postulated that the oxygen molecules transported by CsMb1 from host environments are provided to cells in the parenchyma and intrauterine eggs/sex organs of the worms by CsMb1 and CsMb3, respectively, for energy metabolism and eggshell formation. Other globin homologs were likely to perform non-respiratory functions. In addition, the oxygenated form of secreted CsMb1 seemed to participate in the scavenging of nitric oxide generated by host immune cells via its nitric oxide dioxygenase activity to increase the survival of the parasite.
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Affiliation(s)
- Seon-Hee Kim
- Department of Microbiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Republic of Korea
| | - Dongki Yang
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Republic of Korea
- * E-mail: (DY); (Y-AB)
| | - Young-An Bae
- Department of Microbiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Republic of Korea
- * E-mail: (DY); (Y-AB)
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Staerck C, Yaakoub H, Vandeputte P, Tabiasco J, Godon C, Gastebois A, Giraud S, Guillemette T, Calenda A, Delneste Y, Fleury M, Bouchara JP. The Glycosylphosphatidylinositol-Anchored Superoxide Dismutase of Scedosporium apiospermum Protects the Conidia from Oxidative Stress. J Fungi (Basel) 2021; 7:575. [PMID: 34356954 PMCID: PMC8304446 DOI: 10.3390/jof7070575] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 02/07/2023] Open
Abstract
Scedosporium species are common fungal pathogens in patients with cystic fibrosis (CF). To colonize the CF lungs, fungi must cope with the host immune response, especially the reactive oxygen species (ROS) released by phagocytic cells. To this aim, pathogens have developed various antioxidant systems, including superoxide dismutases (SODs) which constitute the first-line protection against oxidative stress. Interestingly, one of the S. apiospermum SOD-encoding genes (SODD gene) exhibits a glycosylphosphatidylinositol (GPI) anchor-binding site and encodes a conidial-specific surface SOD. In this study, a SODDΔ mutant was engineered from a non-homologous end joining-deficient strain (KU70Δ) of S. apiospermum. Compared to its parent strain, the double mutant KU70Δ/SODDΔ exhibited increased susceptibility to various oxidizing agents and triazole antifungals. In addition, the loss of SodD resulted in an increased intracellular killing of the conidia by M1 macrophages derived from human blood monocytes, suggesting the involvement of this superoxide dismutase in the evasion to the host defenses. Nevertheless, one cannot disregard an indirect role of the enzyme in the synthesis or assembly of the cell wall components since transmission electron microscopic analysis revealed a thickening of the inner cell wall layer of the conidia. Further studies are needed to confirm the role of this enzyme in the pathogenesis of Scedosporium infections, including the production of a recombinant protein and study of its protective effect against the infection in a mouse model of scedosporiosis.
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Affiliation(s)
- Cindy Staerck
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Hajar Yaakoub
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Patrick Vandeputte
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Julie Tabiasco
- Université d’Angers, Université de Nantes, CHU Angers, Inserm, CRCINA, SFR ICAT, F-49000 Angers, France; (J.T.); (Y.D.)
| | - Charlotte Godon
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Amandine Gastebois
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Sandrine Giraud
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Thomas Guillemette
- Université d’Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France;
| | - Alphonse Calenda
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Yves Delneste
- Université d’Angers, Université de Nantes, CHU Angers, Inserm, CRCINA, SFR ICAT, F-49000 Angers, France; (J.T.); (Y.D.)
| | - Maxime Fleury
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
| | - Jean-Philippe Bouchara
- Université d’Angers, Université de Bretagne Occidentale, CHU Angers, Groupe d’Etude des Interactions Hôte-Pathogène (GEIHP, EA3142), SFR ICAT, F-49000 Angers, France; (C.S.); (H.Y.); (P.V.); (C.G.); (A.G.); (S.G.); (A.C.); (M.F.)
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Choi G, Kim D, Im H, Choi SH. A Nitric Oxide-Responsive Transcriptional Regulator NsrR Cooperates With Lrp and CRP to Tightly Control the hmpA Gene in Vibrio vulnificus. Front Microbiol 2021; 12:681196. [PMID: 34093504 PMCID: PMC8175989 DOI: 10.3389/fmicb.2021.681196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
Nitric oxide (NO) is an important antimicrobial effector produced by the host innate immune system to counteract invading pathogens. To survive and establish a successful infection, a fulminating human pathogen Vibrio vulnificus expresses the hmpA gene encoding an NO dioxygenase in an NO-responsive manner. In this study, we identified an Rrf2-family transcriptional regulator NsrR that is predicted to contain the Fe-S cluster coordinated by three cysteine residues. Transcriptome analysis showed that NsrR controls the expression of multiple genes potentially involved in nitrosative stress responses. Particularly, NsrR acts as a strong repressor of hmpA transcription and relieves the repression of hmpA upon exposure to NO. Notably, nsrR and hmpA are transcribed divergently, and their promoter regions overlap with each other. Molecular biological analyses revealed that NsrR directly binds to this overlapping promoter region, which is alleviated by loss of the Fe-S cluster, leading to the subsequent derepression of hmpA under nitrosative stress. We further found that a leucine-responsive regulatory protein (Lrp) negatively regulates hmpA in an NsrR-dependent manner by directly binding to the promoter region, presumably resulting in a DNA conformation change to support the repression by NsrR. Meanwhile, a cyclic AMP receptor protein (CRP) positively regulates hmpA probably through repression of nsrR and lrp by directly binding to each promoter region in a sequential cascade. Altogether, this collaborative regulation of NsrR along with Lrp and CRP enables an elaborate control of hmpA transcription, contributing to survival under host-derived nitrosative stress and thereby the pathogenesis of V. vulnificus.
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Affiliation(s)
- Garam Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea
| | - Dukyun Kim
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Hanhyeok Im
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea
| | - Sang Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea
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Marcelli A, Patrizi B, Bonamore A, Boffi A, Becucci M, Foggi P. Exciplex Formation in Lipid-bound Escherichia coli Flavohemoglobin. Chemphyschem 2021; 22:1134-1140. [PMID: 33794073 DOI: 10.1002/cphc.202100019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/30/2021] [Indexed: 11/10/2022]
Abstract
Flavohemoglobins have the particular capability of binding unsaturated and cyclopropanated fatty acids as free acids or phospholipids. Fatty acid binding to the ferric heme results in a weak but direct bonding interaction. Ferrous and ferric protein, in presence or absence of a bound lipid molecule, have been characterized by transient absorption spectroscopy. Measurements have been also carried out both on the ferrous deoxygenated and on the CO bound protein to investigate possible long-range interaction between the lipid acyl chain moiety and the ferrous heme. After excitation of the deoxygenated derivatives the relaxation process reveals a slow dynamics (350 ps) in lipid-bound protein but is not observed in the lipid-free protein. The latter feature and the presence of an extra contribution in the absorption spectrum, indicates that the interaction of iron heme with the acyl chain moiety occurs only in the excited electronic state and not in the ground electronic state. Data analysis highlights the formation of a charge-transfer complex in which the iron ion of the lipid-bound protein in the expanded electronic excited state, possibly represented by a high spin Fe III intermediate, is able to bind to the sixth coordination ligand placed at a distance of at 3.5 Å from the iron. A very small nanosecond geminate rebinding is observed for CO adduct in lipid-free but not in the lipid-bound protein. The presence of the lipid thus appears to inhibit the mobility of CO in the heme pocket.
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Affiliation(s)
- Agnese Marcelli
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy
| | - Barbara Patrizi
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,National Institute of Optics-National Research Council (INO-CNR), Via Madonna del Piano 10, 50019, Sesto Fiorentino (Florence), Italy
| | - Alessandra Bonamore
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Università "Sapienza" di Roma, P. Aldo Moro 5, 00185, Rome, Italy
| | - Alberto Boffi
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Università "Sapienza" di Roma, P. Aldo Moro 5, 00185, Rome, Italy
| | - Maurizio Becucci
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,Department of Chemistry Ugo Schiff, University of Florence, Via Della Lastruccia 3-13, 50019 Sesto Fiorentino, Florence), Italy
| | - Paolo Foggi
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,National Institute of Optics-National Research Council (INO-CNR), Via Madonna del Piano 10, 50019, Sesto Fiorentino (Florence), Italy.,Department of Chemistry, University of Perugia, Via Elce di sotto 8, 06100, Perugia, Italy
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24
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Kotecka K, Kawalek A, Kobylecki K, Bartosik AA. The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa. Int J Mol Sci 2021; 22:ijms22083982. [PMID: 33921535 PMCID: PMC8070244 DOI: 10.3390/ijms22083982] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.
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25
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Bajaj JS, Shamsaddini A, Fagan A, McGeorge S, Gavis E, Sikaroodi M, Brenner LA, Wade JB, Gillevet PM. Distinct gut microbial compositional and functional changes associated with impaired inhibitory control in patients with cirrhosis. Gut Microbes 2021; 13:1953247. [PMID: 34346283 PMCID: PMC8344770 DOI: 10.1080/19490976.2021.1953247] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/07/2021] [Accepted: 06/28/2021] [Indexed: 02/07/2023] Open
Abstract
Most cirrhosis etiologies, such as alcohol, hepatitis C, and obesity, involve behavior that require the loss of inhibitory control. Once cirrhosis develops, patients can also develop cognitive impairment due to minimal hepatic encephalopathy (MHE). Both processes could have distinct imprints on the gut-liver-brain axis. Determine the impact of inhibitory control versus traditional cirrhosis-related cognitive performance on gut microbial composition and function. Outpatients with cirrhosis underwent two tests for MHE: inhibitory control test (MHEICT, computerized associated with response inhibition) and psychometric hepatic encephalopathy score (MHEPHES, paper-pencil HE-specific associated with subcortical impairment) along with stool collection for metagenomics. MHEICT/not, MHEPHES/not, and discordant (positive on one test but negative on the other) were analyzed for demographics, bacterial species, and gut-brain modules (GBM) using multi-variable analyses. Ninety-seven patients [47 (49%) MHEPHES, 76 (78%) MHEICT, 41 discordant] were enrolled. MHEPHES/not: Cirrhosis severity was worse in MHEPHES without differences in alpha/beta diversity on bacterial species or GBMs. Pathobionts (Enterobacteriaceae) and γ-amino-butryic acid (GABA) synthesis GBM were higher in MHEPHES. MHEICT/not: We found similar cirrhosis severity and metagenomic alpha/beta diversity in MHEICT versus not. However, alpha/beta diversity of GBMs were different in MHEICT versus No-MHE patients. Alistipes ihumii, Prevotella copri, and Eubacterium spp. were higher, while Enterococcus spp. were uniquely lower in MHEICT versus no-MHE and discordant comparisons. GBMs belonging to tryptophan, menaquinone, GABA, glutamate, and short-chain fatty acid synthesis were also unique to MHEICT. Gut microbial signature of impaired inhibitory control, which is associated with addictive disorders that can lead to cirrhosis, is distinct from cirrhosis-related cognitive impairment.
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Affiliation(s)
- Jasmohan S Bajaj
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and Richmond VA Medical Center, Richmond, Virginia, USA
| | | | - Andrew Fagan
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and Richmond VA Medical Center, Richmond, Virginia, USA
| | - Sara McGeorge
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and Richmond VA Medical Center, Richmond, Virginia, USA
| | - Edith Gavis
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and Richmond VA Medical Center, Richmond, Virginia, USA
| | | | - Lisa A. Brenner
- Departments of Physical Medicine and Rehabilitation, Psychiatry, & Neurology, VA Rocky Mountain Mental Illness Research Education and Clinical Center, Aurora, Colorado, and University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
| | - James B Wade
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, USA
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26
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Saghaug CS, Klotz C, Kallio JP, Aebischer T, Langeland N, Hanevik K. Genetic Diversity of the Flavohemoprotein Gene of Giardia lamblia: Evidence for High Allelic Heterozygosity and Copy Number Variation. Infect Drug Resist 2020; 13:4531-4545. [PMID: 33376360 PMCID: PMC7755369 DOI: 10.2147/idr.s274543] [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: 07/29/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
Purpose The flavohemoprotein (gFlHb) in Giardia plays an important role in managing nitrosative and oxidative stress, and potentially also in virulence and nitroimidazole drug tolerance. The aim of this study was to analyze the genetic diversity of gFlHb in Giardia assemblages A and B clinical isolates. Methods gFlHb genes from 20 cultured clinical Giardia isolates were subjected to PCR amplification and cloning, followed by Sanger sequencing. Sequences of all cloned PCR fragments from each isolate were analyzed for single nucleotide variants (SNVs) and compared to genomic Illumina sequence data. Identical clone sequences were sorted into alleles, and diversity was further analyzed. The number of gFlHb gene copies was assessed by mining PacBio de novo assembled genomes in eight isolates. Homology models for assessment of SNV's potential impact on protein function were created using Phyre2. Results A variable copy number of the gFlHb gene, between two and six copies, depending on isolate, was found. A total of 37 distinct sequences, representing different alleles of the gFlHb gene, were identified in AII isolates, and 41 were identified in B isolates. In some isolates, up to 12 different alleles were found. The total allelic diversity was high for both assemblages (>0.9) and was coupled with a nucleotide diversity of <0.01. The genetic variation (SNVs per CDS length) was 4.8% in sub-assemblage AII and 5.4% in assemblage B. The number of non-synonymous (ns) SNVs was high in gFIHb of both assemblages, 1.6% in A and 3.0% in B, respectively. Some of the identified nsSNV are predicted to alter protein structure and possibly function. Conclusion In this study, we present evidence that gFlHb, a putative protective enzyme against oxidative and nitrosative stress in Giardia, is a variable copy number gene with high allelic diversity. The genetic variability of gFlHb may contribute metabolic adaptability against metronidazole toxicity.
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Affiliation(s)
- Christina S Saghaug
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Christian Klotz
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Toni Aebischer
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Nina Langeland
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway.,Department of Medicine, Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Norway
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27
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Chou WK, Vaikunthan M, Schröder HV, Link AJ, Kim H, Brynildsen MP. Synergy Screening Identifies a Compound That Selectively Enhances the Antibacterial Activity of Nitric Oxide. Front Bioeng Biotechnol 2020; 8:1001. [PMID: 32984281 PMCID: PMC7477088 DOI: 10.3389/fbioe.2020.01001] [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: 02/12/2020] [Accepted: 07/31/2020] [Indexed: 01/04/2023] Open
Abstract
Antibiotic resistance poses a serious threat to global health. To reinforce the anti-infective arsenal, many novel therapeutic strategies to fight bacterial infections are being explored. Among them, anti-virulence therapies, which target pathways important for virulence, have attracted much attention. Nitric oxide (NO) defense systems have been identified as critical for the pathogenesis of various bacteria, making them an appealing therapeutic target. In this study, we performed chemical screens to identify inhibitors of NO detoxification in Escherichia coli. We found that 2-mercaptobenzothiazole (2-MBT) can potently inhibit cellular detoxification of NO, achieving a level of inhibition that resembled the effect of genetically removing Hmp, the dominant detoxification enzyme under oxygenated conditions. Further analysis revealed that in the presence of NO, 2-MBT impaired the catalysis of Hmp and synthesis of Hmp and other proteins, whereas in its absence there were minimal perturbations to growth and protein synthesis. In addition, by studying the structure-activity relationship of 2-MBT, we found that both sulfur atoms in 2-MBT were vital for its inhibition of NO detoxification. Interestingly, when 2-mercaptothiazole (2-MT), which lacked the benzene ring, was used, differing biological activities were observed, although they too were NO dependent. Specifically, 2-MT could still prohibit NO detoxification, though it did not interfere with Hmp catalysis; rather, it was a stronger inhibitor of protein synthesis and it reduced the transcript levels of hmp, which was not observed with 2-MBT. Overall, these results provide a strong foundation for further exploration of 2-MBT and 2-MT for therapeutic applications.
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Affiliation(s)
- Wen Kang Chou
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
| | - Mathini Vaikunthan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
| | - Hendrik V. Schröder
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
| | - A. James Link
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, NJ, United States
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Hahn Kim
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, NJ, United States
- Small Molecule Screening Center, Princeton University, Princeton, NJ, United States
| | - Mark P. Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
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28
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HGT in the human and skin commensal Malassezia: A bacterially derived flavohemoglobin is required for NO resistance and host interaction. Proc Natl Acad Sci U S A 2020; 117:15884-15894. [PMID: 32576698 DOI: 10.1073/pnas.2003473117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The skin of humans and animals is colonized by commensal and pathogenic fungi and bacteria that share this ecological niche and have established microbial interactions. Malassezia are the most abundant fungal skin inhabitant of warm-blooded animals and have been implicated in skin diseases and systemic disorders, including Crohn's disease and pancreatic cancer. Flavohemoglobin is a key enzyme involved in microbial nitrosative stress resistance and nitric oxide degradation. Comparative genomics and phylogenetic analyses within the Malassezia genus revealed that flavohemoglobin-encoding genes were acquired through independent horizontal gene transfer events from different donor bacteria that are part of the mammalian microbiome. Through targeted gene deletion and functional complementation in Malassezia sympodialis, we demonstrated that bacterially derived flavohemoglobins are cytoplasmic proteins required for nitric oxide detoxification and nitrosative stress resistance under aerobic conditions. RNA-sequencing analysis revealed that endogenous accumulation of nitric oxide resulted in up-regulation of genes involved in stress response and down-regulation of the MalaS7 allergen-encoding genes. Solution of the high-resolution X-ray crystal structure of Malassezia flavohemoglobin revealed features conserved with both bacterial and fungal flavohemoglobins. In vivo pathogenesis is independent of Malassezia flavohemoglobin. Lastly, we identified an additional 30 genus- and species-specific horizontal gene transfer candidates that might have contributed to the evolution of this genus as the most common inhabitants of animal skin.
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29
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Keuschnig C, Gorfer M, Li G, Mania D, Frostegård Å, Bakken L, Larose C. NO and N 2 O transformations of diverse fungi in hypoxia: evidence for anaerobic respiration only in Fusarium strains. Environ Microbiol 2020; 22:2182-2195. [PMID: 32157782 DOI: 10.1111/1462-2920.14980] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 02/21/2020] [Accepted: 03/07/2020] [Indexed: 11/30/2022]
Abstract
Fungal denitrification is claimed to produce non-negligible amounts of N2 O in soils, but few tested species have shown significant activity. We hypothesized that denitrifying fungi would be found among those with assimilatory nitrate reductase, and tested 20 such batch cultures for their respiratory metabolism, including two positive controls, Fusarium oxysporum and Fusarium lichenicola, throughout the transition from oxic to anoxic conditions in media supplemented with NO 2 - . Enzymatic reduction of NO 2 - (NIR) and NO (NOR) was assessed by correcting measured NO- and N2 O-kinetics for abiotic NO- and N2 O-production (sterile controls). Significant anaerobic respiration was only confirmed for the positive controls and for two of three Fusarium solani cultures. The NO kinetics in six cultures showed NIR but not NOR activity, observed through the accumulation of NO. Others had NOR but not NIR activity, thus reducing abiotically produced NO to N2 O. The presence of candidate genes (nirK and p450nor) was confirmed in the positive controls, but not in some of the NO or N2 O accumulating cultures. Based on our results, we conclude that only the Fusarium cultures were able to sustain anaerobic respiration and produced low amounts of N2 O as a response to an abiotic NO production from the medium.
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Affiliation(s)
- Christoph Keuschnig
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Ecole Centrale de Lyon, Université de Lyon, 69134, Ecully Cedex, France
| | - Markus Gorfer
- Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Guofen Li
- Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Daniel Mania
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, 1432, Aas, Norway
| | - Åsa Frostegård
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, 1432, Aas, Norway
| | - Lars Bakken
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, 1432, Aas, Norway
| | - Catherine Larose
- Environmental Microbial Genomics, Laboratoire Ampère, CNRS UMR 5005, Ecole Centrale de Lyon, Université de Lyon, 69134, Ecully Cedex, France
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30
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Abstract
Flavohaemoglobins were first described in yeast as early as the 1970s but their functions were unclear. The surge in interest in nitric oxide biology and both serendipitous and hypothesis-driven discoveries in bacterial systems have transformed our understanding of this unusual two-domain globin into a comprehensive, yet undoubtedly incomplete, appreciation of its pre-eminent role in nitric oxide detoxification. Here, I focus on research on the flavohaemoglobins of microorganisms, especially of bacteria, and update several earlier and more comprehensive reviews, emphasising advances over the past 5 to 10 years and some controversies that have arisen. Inevitably, in light of space restrictions, details of nitric oxide metabolism and globins in higher organisms are brief.
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Affiliation(s)
- Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Sheffield, S10 2TN, UK
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31
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Le VVH, Olivera C, Spagnuolo J, Davies IG, Rakonjac J. In vitro synergy between sodium deoxycholate and furazolidone against enterobacteria. BMC Microbiol 2020; 20:5. [PMID: 31906851 PMCID: PMC6945529 DOI: 10.1186/s12866-019-1668-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 11/29/2019] [Indexed: 12/11/2022] Open
Abstract
Background Antimicrobial combinations have been proven as a promising approach in the confrontation with multi-drug resistant bacterial pathogens. In the present study, we identify and characterize a synergistic interaction of broad-spectrum nitroreductase-activated prodrugs 5-nitrofurans, with a secondary bile salt, sodium deoxycholate (DOC) in growth inhibition and killing of enterobacteria. Results Using checkerboard assay, we show that combination of nitrofuran furazolidone (FZ) and DOC generates a profound synergistic effect on growth inhibition in several enterobacterial species including Escherichia coli, Salmonella enterica, Citrobacter gillenii and Klebsiella pneumoniae. The Fractional Inhibitory Concentration Index (FICI) for DOC-FZ synergy ranges from 0.125 to 0.35 that remains unchanged in an ampicillin-resistant E. coli strain containing a β-lactamase-producing plasmid. Findings from the time-kill assay further highlight the synergy with respect to bacterial killing in E. coli and Salmonella. We further characterize the mechanism of synergy in E. coli K12, showing that disruption of the tolC or acrA genes that encode components of multidrug efflux pumps causes, respectively, a complete or partial loss, of the DOC-FZ synergy. This finding indicates the key role of TolC-associated efflux pumps in the DOC-FZ synergy. Overexpression of nitric oxide-detoxifying enzyme Hmp results in a three-fold increase in FICI for DOC-FZ interaction, suggesting a role of nitric oxide in the synergy. We further demonstrate that DOC-FZ synergy is largely independent of NfsA and NfsB, the two major activation enzymes of the nitrofuran prodrugs. Conclusions This study is to our knowledge the first report of nitrofuran-deoxycholate synergy against Gram-negative bacteria, offering potential applications in antimicrobial therapeutics. The mechanism of DOC-FZ synergy involves FZ-mediated inhibition of TolC-associated efflux pumps that normally remove DOC from bacterial cells. One possible route contributing to that effect is via FZ-mediated nitric oxide production.
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Affiliation(s)
- Vuong Van Hung Le
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Catrina Olivera
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Julian Spagnuolo
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Present Address: Department of Biomedicine, University Hospital Basel, 4031, Basel, Switzerland
| | - Ieuan G Davies
- New Zealand Pharmaceuticals Ltd, Palmerston North, New Zealand
| | - Jasna Rakonjac
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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32
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Butcher D, Moussaoui M, Baciou L, Miksovska J. Impact of azole drugs on energetics, kinetics, and ligand migration pathways of CO photo-dissociation in bacterial flavohemoglobins. RSC Adv 2020; 10:17930-17941. [PMID: 35515592 PMCID: PMC9053618 DOI: 10.1039/d0ra02529a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/21/2020] [Indexed: 01/18/2023] Open
Abstract
Flavohemoglobins (fHbs) are heme proteins found in prokaryotic and eukaryotic microbes. They are involved in NO detoxification through an NO˙ dioxygenase mechanism. The N-terminal heme globin domain allows for binding of gaseous ligands whereas a C-terminal NADH/FADH binding domain facilitates association of redox cofactors necessary for ligand reduction. The NO˙ dioxygenase function is important in facilitating immune resistance by protecting the cell from nitrosative stress brought about by a host organism; as a result, bacterial flavoHbs have recently been considered as targets for the development of new antibiotics. Here, photoacoustic calorimetry and transient absorption spectroscopy have been used to characterize energetics, structural dynamics, and kinetics of CO migration within bacterial flavoHbs from Ralstonia eutropha (FHP) and Staphylococcus aureus (HMPSa) in the presence and absence of antibiotic azole compounds. In FHP, the ligand photo-release is associated with ΔH = 26.2 ± 7.0 kcal mol−1 and ΔV = 25.0 ± 1.5 mL mol−1 while in HMPSa, ΔH = 34.7 ± 8.0 kcal mol−1 and ΔV = 28.6 ± 17 mL mol−1 were observed, suggesting distinct structural changes associated with ligand escape from FHP and HMPSa. In the presence of ketoconazole, the CO escape leads to a more negative enthalpy change and volume change whereas association of miconazole to FHP or HMPSa does not impact the reaction volume. These data are in agreement with the computational results that propose distinct binding sites for ketoconazole and miconazole on CO bound FHP. Miconazole or ketoconazole binding to either protein has only a negligible impact on the CO association rates, indicating that azole drugs do not impact flavoHbs interactions with gaseous ligands but may inhibit the NOD activity through preventing the electron transfer between FAD and heme cofactors. Impact of ketoconalzole and miconazole on structural dynamics of flavohemoglobin.![]()
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Affiliation(s)
- David Butcher
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Myriam Moussaoui
- Laboratoire de Chimie Physique
- UMR8000
- Université Paris Sud
- CNRS
- Université Paris Saclay
| | - Laura Baciou
- Laboratoire de Chimie Physique
- UMR8000
- Université Paris Sud
- CNRS
- Université Paris Saclay
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
- Biomolecular Sciences Institute
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33
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Edwards MJ, Richardson DJ, Paquete CM, Clarke TA. Role of multiheme cytochromes involved in extracellular anaerobic respiration in bacteria. Protein Sci 2019; 29:830-842. [PMID: 31721352 PMCID: PMC7096707 DOI: 10.1002/pro.3787] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 01/08/2023]
Abstract
Heme containing proteins are involved in a broad range of cellular functions, from oxygen sensing and transport to catalyzing oxidoreductive reactions. The two major types of cytochrome (b-type and c-type) only differ in their mechanism of heme attachment, but this has major implications for their cellular roles in both localization and mechanism. The b-type cytochromes are commonly cytoplasmic, or are within the cytoplasmic membrane, while c-type cytochromes are always found outside of the cytoplasm. The mechanism of heme attachment allows for complex c-type multiheme complexes, having the capacity to hold multiple electrons, to be assembled. These are increasingly being identified as secreted into the extracellular environment. For organisms that respire using extracellular substrates, these large multiheme cytochromes allow for electron transfer networks from the cytoplasmic membrane to the cell exterior for the reduction of extracellular electron acceptors. In this review the structures and functions of these networks and the mechanisms by which electrons are transferred to extracellular substrates is described.
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Affiliation(s)
- Marcus J Edwards
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - David J Richardson
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - Catarina M Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Oeiras, Portugal
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
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34
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Kim D, Na EJ, Kim S, Kim JS, Jung YH, Cao J, Han HJ, Bang IS, Yoo JW, Ha NC, Choi SH. Transcriptomic Identification and Biochemical Characterization of HmpA, a Nitric Oxide Dioxygenase, Essential for Pathogenesis of Vibrio vulnificus. Front Microbiol 2019; 10:2208. [PMID: 31616401 PMCID: PMC6768983 DOI: 10.3389/fmicb.2019.02208] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/09/2019] [Indexed: 12/29/2022] Open
Abstract
Nitric oxide (NO) and its derivatives are important effectors of host innate immunity, disrupting cellular function of infecting pathogens. Transcriptome analysis of Vibrio vulnificus, an opportunistic human pathogen, identified a set of genes induced upon exposure to NO. Among them, VvhmpA (V. vulnificus hmpA), encoding a multidomain NO dioxygenase, was the most greatly induced upon exposure to NO and was thus further characterized. Absorption spectra demonstrated that VvHmpA is a heme protein in which the heme iron can exist in either reduced, NO-bound, or oxidized state. Biochemical studies revealed that VvHmpA is a flavohemoglobin containing equimolar amounts of heme and FAD as cofactors. The KM and kcat values of VvHmpA for NO at 37°C, the temperature encountered by V. vulnificus in the host, were greater than those at 30°C, indicating that VvHmpA detoxifies high levels of NO effectively during infection. Compared with the wild type, the VvhmpA mutant exhibited a lower NO-decomposition activity and impaired growth in the presence of NO in vitro. Also, the cytotoxicity and survival of the VvhmpA mutant infecting the NO-producing murine macrophage cells were lower than those of the wild type. Furthermore, the mouse lethality of the VvhmpA mutant was reduced compared to that of the parental wild type. The combined results revealed that VvHmpA is a potent virulence factor that is induced upon exposure to NO and important for the survival and pathogenesis of V. vulnificus during infection.
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Affiliation(s)
- Dukyun Kim
- National Research Laboratory of Molecular Microbiology and Toxicology, Seoul National University, Seoul, South Korea.,Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
| | - Eun Jung Na
- National Research Laboratory of Molecular Microbiology and Toxicology, Seoul National University, Seoul, South Korea.,Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
| | - Suhyeon Kim
- Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
| | - Jung Sung Kim
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, South Korea
| | - Young Hyun Jung
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Medicine, BK21 PLUS Creative Veterinary Research Center, Seoul National University, Seoul, South Korea
| | - Jiafu Cao
- College of Pharmacy, Pusan National University, Busan, South Korea
| | - Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Medicine, BK21 PLUS Creative Veterinary Research Center, Seoul National University, Seoul, South Korea
| | - Iel Soo Bang
- Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, South Korea
| | - Jin-Wook Yoo
- College of Pharmacy, Pusan National University, Busan, South Korea
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
| | - Sang Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Seoul National University, Seoul, South Korea.,Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
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35
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Shimizu T, Matsumoto A, Noda M. Cooperative Roles of Nitric Oxide-Metabolizing Enzymes To Counteract Nitrosative Stress in Enterohemorrhagic Escherichia coli. Infect Immun 2019; 87:e00334-19. [PMID: 31209149 PMCID: PMC6704613 DOI: 10.1128/iai.00334-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 06/08/2019] [Indexed: 11/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) has at least three enzymes, NorV, Hmp, and Hcp, that act independently to lower the toxicity of nitric oxide (NO), a potent antimicrobial molecule. This study aimed to reveal the cooperative roles of these defensive enzymes in EHEC against nitrosative stress. Under anaerobic conditions, combined deletion of all three enzymes significantly increased the NO sensitivity of EHEC determined by the growth at late stationary phase; however, the expression of norV restored the NO resistance of EHEC. On the other hand, the growth of Δhmp mutant EHEC was inhibited after early stationary phase, indicating that NorV and Hmp play a cooperative role in anaerobic growth. Under microaerobic conditions, the growth of Δhmp mutant EHEC was inhibited by NO, indicating that Hmp is the enzyme that protects cells from NO stress under microaerobic conditions. When EHEC cells were exposed to a lower concentration of NO, the NO level in bacterial cells of Δhcp mutant EHEC was higher than those of the other EHEC mutants, suggesting that Hcp is effective at regulating NO levels only at a low concentration. These findings of a low level of NO in bacterial cells with hcp indicate that the NO consumption activity of Hcp was suppressed by Hmp at a low range of NO concentrations. Taken together, these results show that the cooperative effects of NO-metabolizing enzymes are regulated by the range of NO concentrations to which the EHEC cells are exposed.
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Affiliation(s)
- Takeshi Shimizu
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Akio Matsumoto
- Department of Aging Pharmacology, School of Medicine, Toho University, Tokyo, Japan
| | - Masatoshi Noda
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
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36
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Staerck C, Tabiasco J, Godon C, Delneste Y, Bouchara JP, Fleury MJJ. Transcriptional profiling of Scedosporium apiospermum enzymatic antioxidant gene battery unravels the involvement of thioredoxin reductases against chemical and phagocytic cells oxidative stress. Med Mycol 2019; 57:363-373. [PMID: 29889264 DOI: 10.1093/mmy/myy033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/22/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022] Open
Abstract
Scedosporium species rank the second, after Aspergillus fumigatus, among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF). Development of microorganisms in the respiratory tract depends on their capacity to evade killing by the host immune system, particularly through the oxidative response of macrophages and neutrophils, with the release of reactive oxygen species (ROS) and reactive nitrogen species (RNS). This is particularly true in the airways of CF patients which display an exacerbated inflammatory reaction. To protect themselves, pathogens have developed various enzymatic antioxidant systems implicated in ROS degradation, including superoxide dismutases, catalases, cytochrome C peroxidases, chloroperoxidases and enzymes of the glutathione and thioredoxin systems, or in RNS degradation, that is, flavohemoglobins, nitrate reductases, and nitrite reductases. Here we investigated the transcriptional regulation of the enzymatic antioxidant gene battery in 24-h-old hyphae of Scedosporium apiospermum in response to oxidative stress induced chemically or by exposure to activated phagocytic cells. We showed that 21 out of the 33 genes potentially implicated in the oxidative or nitrosative stress response were overexpressed upon exposure of the fungus to various chemical oxidants, while they were only 13 in co-cultures with macrophages or neutrophils. Among them, genes encoding two thioredoxin reductases and to a lesser extent, a peroxiredoxin and one catalase were found to be overexpressed after chemical oxidative stress as well as in co-cultures. These results suggest that thioredoxin reductases, which are known to be virulence factors in other pathogenic fungi, play a key role in pathogenesis of scedosporiosis, and may be new drug targets.
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Affiliation(s)
- Cindy Staerck
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Julie Tabiasco
- CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France
| | - Charlotte Godon
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Yves Delneste
- CRCINA, INSERM, Université de Nantes, Université d'Angers, Angers, France.,Laboratoire d'Immunologie et Allergologie, Centre Hospitalier Universitaire d'Angers, France
| | - Jean-Philippe Bouchara
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France.,Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Angers, France
| | - Maxime J J Fleury
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
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37
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Abstract
The genus Vibrio includes serious human pathogens, and mollusks are a significant reservoir for species such as V. vulnificus. Vibrio species encode PecS, a member of the multiple antibiotic resistance regulator (MarR) family of transcription factors; pecS is divergently oriented to pecM, which encodes an efflux pump. We report here that Vibrio species feature frequent duplications of pecS-pecM genes, suggesting evolutionary pressures to respond to distinct environmental situations. The single V. vulnificus PecS binds two sites within the pecS-pecM intergenic region with Kd = 0.3 ± 0.1 nM, a binding that is attenuated by the ligands xanthine and urate, except when promoter DNA is saturated with PecS. A unique target is found in the intergenic region between genes encoding the nitric oxide sensing transcription factor, NsrR, and nod; the nod-encoded nitric oxide dioxygenase is important for preventing nitric oxide stress. Reporter gene assays show that PecS-mediated repression of gene expression can be relieved in presence of ligand. Since xanthine and urate are produced as part of the oxidative burst during host defenses and under molluscan hypoxia, we propose that these intermediates in the host purine degradation pathway function to promote bacterial survival during hypoxia and oxidative stress.
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38
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Cao JX, Wang F, Li X, Sun YY, Wang Y, Ou CR, Shao XF, Pan DD, Wang DY. The Influence of Microwave Sterilization on the Ultrastructure, Permeability of Cell Membrane and Expression of Proteins of Bacillus Cereus. Front Microbiol 2018; 9:1870. [PMID: 30233502 PMCID: PMC6131623 DOI: 10.3389/fmicb.2018.01870] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 07/25/2018] [Indexed: 12/02/2022] Open
Abstract
Bacillus cereus was isolated from ready-to-serve brine goose, identified by 16S rRNA gene sequencing analysis and treated with a commercial microwave sterilization condition (a power of 1,800 W at 85°C for 5 min). The influence of microwaves on the morphology, the permeability of membrane and the expression of total bacterial proteins was observed. Microwave induced the clean of bacterial nuclear chromatin, increased the permeability and disrupted the integrity of membrane. Twenty-three proteins including 18 expressed down-regulated proteins and 5 expressed up-regulated proteins were identified by HPLC-MS/MS in the samples treated with microwave. The frequencies of proteins changed after microwaves treatment were labeled as 39.13% (synthesis and metabolism of amino acid or proteins), 21.74% (carbohydrate metabolism), 8.70% (anti-oxidant and acetyl Co-A synthesis), and 4.35% (the catalyst of catabolism of bacterial acetoin, ethanol metabolism, glyoxylate pathway, butyrate synthesis and detoxification activity), respectively. This study indicates that microwaves result in the inactivation of Bacillus cereus by cleaning nuclear chromatin, disrupting cell membrane and disordering the expression of proteins.
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Affiliation(s)
- Jin-Xuan Cao
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Fang Wang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Xuan Li
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Yang-Ying Sun
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Ying Wang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Chang-Rong Ou
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Xing-Feng Shao
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Dao-Dong Pan
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Dao-Ying Wang
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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39
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Moussaoui M, Misevičienė L, Anusevičius Ž, Marozienė A, Lederer F, Baciou L, Čėnas N. Quinones and nitroaromatic compounds as subversive substrates of Staphylococcus aureus flavohemoglobin. Free Radic Biol Med 2018; 123:107-115. [PMID: 29793040 DOI: 10.1016/j.freeradbiomed.2018.05.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/09/2018] [Accepted: 05/18/2018] [Indexed: 11/23/2022]
Abstract
In microorganisms, flavohemoglobins (FHbs) containing FAD and heme (Fe3+, metHb) convert NO. into nitrate at the expense of NADH and O2. FHbs contribute to bacterial resistance to nitrosative stress. Therefore, inhibition of FHbs functions may decrease the pathogen virulence. We report here a kinetic study of the reduction of quinones and nitroaromatic compounds by S. aureus FHb. We show that this enzyme rapidly reduces quinones and nitroaromatic compounds in a mixed single- and two-electron pathway. The reactivity of nitroaromatics increased upon an increase in their single-electron reduction potential (E17), whereas the reactivity of quinones poorly depended on their E17 with a strong preference for a 2-hydroxy-1,4-naphthoquinone structure. The reaction followed a 'ping-pong' mechanism. In general, the maximal reaction rates were found lower than the maximal presteady-state rate of FAD reduction by NADH and/or of oxyhemoglobin (HbFe2+O2) formation (~130 s-1, pH 7.0, 25 °C), indicating that the enzyme turnover is limited by the oxidative half-reaction. The turnover studies showed that quinones prefreqently accept electrons from reduced FAD, and not from HbFe2+O2. These results suggest that quinones and nitroaromatics act as 'subversive substrates' for FHb, and may enhance the cytotoxicity of NO. by formation of superoxide and by diverting the electron flux coming from reduced FAD. Because quinone reduction rate was increased by FHb inhibitors such as econazole, ketoconazole, and miconazole, their combined use may represent a novel chemotherapeutical approach.
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Affiliation(s)
- Myriam Moussaoui
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Lina Misevičienė
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Žilvinas Anusevičius
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Audronė Marozienė
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Florence Lederer
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Laura Baciou
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Narimantas Čėnas
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania.
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40
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Abstract
Urinary tract infection (UTI) is one of the most common bacterial infections in humans, and the majority are caused by uropathogenic Escherichia coli (UPEC). The rising antibiotic resistance among UPEC and the frequent failure of antibiotics to effectively treat recurrent UTI and catheter-associated UTI motivate research on alternative ways of managing UTI. Abundant evidence indicates that the toxic radical nitric oxide (NO), formed by activation of the inducible nitric oxide synthase, plays an important role in host defence to bacterial infections, including UTI. The major source of NO production during UTI is from inflammatory cells, especially neutrophils, and from the uroepithelial cells that are known to orchestrate the innate immune response during UTI. NO and reactive nitrogen species have a wide range of antibacterial targets, including DNA, heme proteins, iron-sulfur clusters, and protein thiol groups. However, UPEC have acquired a variety of defence mechanisms for protection against NO, such as the NO-detoxifying enzyme flavohemoglobin and the NO-tolerant cytochrome bd-I respiratory oxidase. The cytotoxicity of NO-derived intermediates is nonspecific and may be detrimental to host cells, and a balanced NO production is crucial to maintain the tissue integrity of the urinary tract. In this review, we will give an overview of how NO production from host cells in the urinary tract is activated and regulated, the effect of NO on UPEC growth and colonization, and the ability of UPEC to protect themselves against NO. We also discuss the attempts that have been made to develop NO-based therapeutics for UTI treatment.
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41
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Ras G, Leroy S, Talon R. Nitric oxide synthase: What is its potential role in the physiology of staphylococci in meat products? Int J Food Microbiol 2018; 282:28-34. [PMID: 29890305 DOI: 10.1016/j.ijfoodmicro.2018.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/23/2018] [Accepted: 06/06/2018] [Indexed: 12/17/2022]
Abstract
Coagulase-negative staphylococci are frequently isolated from meat products and two species are used as starter cultures in dry fermented sausages. In these products, they face various environmental conditions such as variation of redox potential and oxygen levels that can lead to oxidative stress. Furthermore, when nitrate and nitrite are added as curing salts, staphylococci also experience nitrosative stress. A nos gene encoding a nitric oxide synthase (NOS) is present in the genome of all staphylococci. NOS produces nitric oxide (NO) and citrulline from arginine, but its activity is still poorly characterized, particularly in coagulase-negative staphylococci. NO is highly reactive with a broad spectrum of activity resulting from targeting metal centres (heme and non-heme) and protein thiols. At low concentration, NO acts as a signalling molecule, while at higher concentration it generates stress. Thus, it was initially suggested that staphylococcal NOS counteract oxidative stress in relation to PerR and Fur regulators. In the physiology of staphylococci, it has recently been highlighted that NO controls the rate of aerobic respiration and regulates the transition from aerobic to nitrate respiration and also helps maintain the membrane potential in relation to the two-component systems SrrAB and AirRS. As NO interacts with heme centres, it binds the heme iron atom of myoglobin to form nitrosomyglobin, which is the typical red pigment of cured meat. However, the contribution of NOS to this reaction in meat products has yet to be evaluated.
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Affiliation(s)
- Geoffrey Ras
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France; CHR. HANSEN SAS, Saint-Germain-les-Arpajon, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Régine Talon
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France.
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42
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Cao JX, Wang F, Li X, Sun YY, Wang Y, Ou CR, Shao XF, Pan DD, Wang DY. The Influence of Microwave Sterilization on the Ultrastructure, Permeability of Cell Membrane and Expression of Proteins of Bacillus Cereus. Front Microbiol 2018; 9:1870. [PMID: 30233502 DOI: 10.3389/fmicb.2018.0187010.3389/fmicb.2018.01870.s001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 07/25/2018] [Indexed: 05/20/2023] Open
Abstract
Bacillus cereus was isolated from ready-to-serve brine goose, identified by 16S rRNA gene sequencing analysis and treated with a commercial microwave sterilization condition (a power of 1,800 W at 85°C for 5 min). The influence of microwaves on the morphology, the permeability of membrane and the expression of total bacterial proteins was observed. Microwave induced the clean of bacterial nuclear chromatin, increased the permeability and disrupted the integrity of membrane. Twenty-three proteins including 18 expressed down-regulated proteins and 5 expressed up-regulated proteins were identified by HPLC-MS/MS in the samples treated with microwave. The frequencies of proteins changed after microwaves treatment were labeled as 39.13% (synthesis and metabolism of amino acid or proteins), 21.74% (carbohydrate metabolism), 8.70% (anti-oxidant and acetyl Co-A synthesis), and 4.35% (the catalyst of catabolism of bacterial acetoin, ethanol metabolism, glyoxylate pathway, butyrate synthesis and detoxification activity), respectively. This study indicates that microwaves result in the inactivation of Bacillus cereus by cleaning nuclear chromatin, disrupting cell membrane and disordering the expression of proteins.
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Affiliation(s)
- Jin-Xuan Cao
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Fang Wang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Xuan Li
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Yang-Ying Sun
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Ying Wang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Chang-Rong Ou
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Xing-Feng Shao
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Dao-Dong Pan
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, China
| | - Dao-Ying Wang
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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43
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Transcription factors Atf1 and Sty1 promote stress tolerance under nitrosative stress in Schizosaccharomyces pombe. Microbiol Res 2018; 206:82-90. [DOI: 10.1016/j.micres.2017.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/28/2017] [Accepted: 10/07/2017] [Indexed: 01/22/2023]
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44
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Gell DA. Structure and function of haemoglobins. Blood Cells Mol Dis 2017; 70:13-42. [PMID: 29126700 DOI: 10.1016/j.bcmd.2017.10.006] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 10/29/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
Haemoglobin (Hb) is widely known as the iron-containing protein in blood that is essential for O2 transport in mammals. Less widely recognised is that erythrocyte Hb belongs to a large family of Hb proteins with members distributed across all three domains of life-bacteria, archaea and eukaryotes. This review, aimed chiefly at researchers new to the field, attempts a broad overview of the diversity, and common features, in Hb structure and function. Topics include structural and functional classification of Hbs; principles of O2 binding affinity and selectivity between O2/NO/CO and other small ligands; hexacoordinate (containing bis-imidazole coordinated haem) Hbs; bacterial truncated Hbs; flavohaemoglobins; enzymatic reactions of Hbs with bioactive gases, particularly NO, and protection from nitrosative stress; and, sensor Hbs. A final section sketches the evolution of work on the structural basis for allosteric O2 binding by mammalian RBC Hb, including the development of newer kinetic models. Where possible, reference to historical works is included, in order to provide context for current advances in Hb research.
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Affiliation(s)
- David A Gell
- School of Medicine, University of Tasmania, TAS 7000, Australia.
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45
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Lukaszewicz B, McColl E, Yee J, Rafferty S, Couture M. Resonance Raman studies on the flavohemoglobin of the protist Giardia intestinalis: evidence of a type I/II-peroxidase-like heme environment and roles of the active site distal residues. J Biol Inorg Chem 2017; 22:1099-1108. [PMID: 28884403 DOI: 10.1007/s00775-017-1487-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/16/2017] [Indexed: 12/11/2022]
Abstract
Flavohemoglobins are microbial enzymes that counter nitrosative stress, but the details of their underlying enzymatic activities and structure-function relationships are not completely understood. These enzymes have been identified in Gram-negative bacteria, certain fungi, and the parasitic protist Giardia intestinalis (gFlHb) which, despite lacking the ability to make heme, encodes several hemeproteins. To gain knowledge about the biophysical properties of the active site of gFlHb, we used resonance Raman spectroscopy to probe the wild-type protein and variants at globin domain positions E11, E7, and B10 on the distal, ligand-binding side of the heme. The heme of gFlHb has a peroxidase-like environment resembling that of the well-characterized E. coli flavohemoglobin HMP. We provide evidence that gFlHb has two Fe-His stretching modes, a feature that also occurs in type I/II-peroxidases in which a proximal histidine with strong imidazolate character and a nearby carboxylic acid residue can exist as a tautomeric pair depending on the position of a shared proton. Characterization of the distal variants Tyr30Phe, Gln54Leu, and Leu59Ala shows that TyrB10 and GlnE7 but not LeuE11 are implicated in stabilisation of bound exogenous ligands such as CO and O2. Our work revealed that several biophysical properties of the heme active site of gFlHb are highly conserved compared to HMP and suggest that they are conserved across the flavohemoglobin family.
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Affiliation(s)
- Brian Lukaszewicz
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada
| | - Eliza McColl
- Biology Department, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada
| | - Janet Yee
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.,Biology Department, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada
| | - Steven Rafferty
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.
| | - Manon Couture
- Department of Biochemistry, Microbiology and Bioinformatics, Université Laval, IBIS and PROTEO, 1030 Ave de la Médecine, Québec, QC, G1V 0A6, Canada.
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46
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Staerck C, Gastebois A, Vandeputte P, Calenda A, Larcher G, Gillmann L, Papon N, Bouchara JP, Fleury MJ. Microbial antioxidant defense enzymes. Microb Pathog 2017. [DOI: 10.1016/j.micpath.2017.06.015] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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47
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Nitrosative stress defences of the enterohepatic pathogenic bacterium Helicobacter pullorum. Sci Rep 2017; 7:9909. [PMID: 28855660 PMCID: PMC5577044 DOI: 10.1038/s41598-017-10375-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 08/07/2017] [Indexed: 01/28/2023] Open
Abstract
Helicobacter pullorum is an avian bacterium that causes gastroenteritis, intestinal bowel and hepatobiliary diseases in humans. Although H. pullorum has been shown to activate the mammalian innate immunity with release of nitric oxide (NO), the proteins that afford protection against NO and reactive nitrogen species (RNS) remain unknown. Here several protein candidates of H. pullorum, namely a truncated (TrHb) and a single domain haemoglobin (SdHb), and three peroxiredoxin-like proteins (Prx1, Prx2 and Prx3) were investigated. We report that the two haemoglobin genes are induced by RNS, and that SdHb confers resistance to nitrosative stress both in vitro and in macrophages. For peroxiredoxins, the prx2 and prx3 expression is enhanced by peroxynitrite and hydrogen peroxide, respectively. Mutation of prx1 does not alter the resistance to these stresses, while the single ∆prx2 and double ∆prx1∆prx2 mutants have decreased viability. To corroborate the physiological data, the biochemical analysis of the five recombinant enzymes was done, namely by stopped-flow spectrophotometry. It is shown that H. pullorum SdHb reacts with NO much more quickly than TrHb, and that the three Prxs react promptly with peroxynitrite, Prx3 displaying the highest reactivity. Altogether, the results unveil SdHb and Prx3 as major protective systems of H. pullorum against nitrosative stress.
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Enzymatic Mechanisms Involved in Evasion of Fungi to the Oxidative Stress: Focus on Scedosporium apiospermum. Mycopathologia 2017. [DOI: 10.1007/s11046-017-0160-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Yang F, Ning K, Zeng X, Zhou Q, Su X, Yuan X. Characterization of saliva microbiota's functional feature based on metagenomic sequencing. SPRINGERPLUS 2016; 5:2098. [PMID: 28053828 PMCID: PMC5174016 DOI: 10.1186/s40064-016-3728-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 11/23/2016] [Indexed: 01/18/2023]
Abstract
Objective
Saliva, a mixture of exocrinally secretive fluids, amounts to ~1.5 L daily and harbors numerous microbial inhabitants. However, except the organismal structure of saliva microbiota, the functional profile of saliva microbiota remain elusive. Methods Here we used metagenomic sequencing to experimentally reconstruct the global genomic profile of saliva by sequencing total saliva DNA from two healthy and two caries-active (DMFT ≧ 6) adults. Results We found that saliva microbiota, representing 30–60% of total saliva DNA in our samples, might carry functional signatures that were site-specific and caries-state-specific. Among microbiota from different hosts, a prominent functional core, but not an organismal core, was identified. Each microbiota exhibited functional redundancy where dominant genomes tend to encode more functional diversity yet without necessarily contributing to dominant functions. Furthermore, genetic polymorphisms of hosts were also unraveled from salivary DNA without apparent physical or sequence bias in human chromosomes. Conclusions The microbial functional sensitivity to disease, links to specific functions, and permission of simultaneous genotyping of hosts and microbiota suggested sequencing salivary DNA might be an advantageous venue in uncovering both human and microbial basis of oral infections. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-3728-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fang Yang
- Department of Stomatology, Qingdao Municipal Hospital, Qingdao, 266011 Shandong China
| | - Kang Ning
- Shandong Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels and BioEnergy Genome Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 Shandong China
| | - Xiaowei Zeng
- Shandong Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels and BioEnergy Genome Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 Shandong China
| | - Qian Zhou
- Shandong Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels and BioEnergy Genome Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 Shandong China
| | - Xiaoquan Su
- Shandong Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels and BioEnergy Genome Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 Shandong China
| | - Xiao Yuan
- Department of Stomatology, Qingdao Municipal Hospital, Qingdao, 266011 Shandong China
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Flint A, Stintzi A, Saraiva LM. Oxidative and nitrosative stress defences of Helicobacter and Campylobacter species that counteract mammalian immunity. FEMS Microbiol Rev 2016; 40:938-960. [PMID: 28201757 PMCID: PMC5091033 DOI: 10.1093/femsre/fuw025] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/29/2016] [Accepted: 07/02/2016] [Indexed: 12/18/2022] Open
Abstract
Helicobacter and Campylobacter species are Gram-negative microaerophilic host-associated heterotrophic bacteria that invade the digestive tract of humans and animals. Campylobacter jejuni is the major worldwide cause of foodborne gastroenteritis in humans, while Helicobacter pylori is ubiquitous in over half of the world's population causing gastric and duodenal ulcers. The colonisation of the gastrointestinal system by Helicobacter and Campylobacter relies on numerous cellular defences to sense the host environment and respond to adverse conditions, including those imposed by the host immunity. An important antimicrobial tool of the mammalian innate immune system is the generation of harmful oxidative and nitrosative stresses to which pathogens are exposed during phagocytosis. This review summarises the regulators, detoxifying enzymes and subversion mechanisms of Helicobacter and Campylobacter that ultimately promote the successful infection of humans.
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Affiliation(s)
- Annika Flint
- Ottawa Institute of Systems Biology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Alain Stintzi
- Ottawa Institute of Systems Biology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Lígia M. Saraiva
- Instituto de Tecnologia Química e Biológica, NOVA, Av. da República, 2780-157 Oeiras, Portugal
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