1
|
Ou C, Dozois CM, Daigle F. Differential regulatory control of curli (csg) gene expression in Salmonella enterica serovar Typhi requires more than a functional CsgD regulator. Sci Rep 2023; 13:14905. [PMID: 37689734 PMCID: PMC10492818 DOI: 10.1038/s41598-023-42027-y] [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: 06/20/2023] [Accepted: 09/04/2023] [Indexed: 09/11/2023] Open
Abstract
The human-specific Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a systemic disease with no known reservoir. Curli fimbriae are major components of biofilm produced by Salmonella and are encoded by the csg gene cluster (csgBAC and csgDEFG). The role of curli in S. Typhi is unknown, although detection of anti-curli antibodies suggests they are produced during host infection. In this study, we investigated curli gene expression in S. Typhi. We demonstrated that the CsgD regulatory protein binds weakly to the csgB promoter. Yet, replacing S. Typhi csgD with the csgD allele from S. Typhimurium did not modify the curli negative phenotype on Congo Red medium suggesting that differential regulation of curli gene expression in S. Typhi is not dependent on modification of the CsgD regulator. The entire csg gene cluster from S. Typhimurium was also cloned into S. Typhi, but again, despite introduction of a fully functional csg gene cluster from S. Typhimurium, curli were still not detected in S. Typhi. Thus, in addition to intrinsic genomic differences in the csg gene cluster that have resulted in production of a modified CsgD protein, S. Typhi has likely undergone other changes independent of the csg gene cluster that have led to distinctive regulation of csg genes compared to other Salmonella serovars.
Collapse
Affiliation(s)
- Camille Ou
- Department of Microbiology, Infectiology and Immunology, University of Montréal, 2900 Bd Édouard-Montpetit, Montreal, QC, H3T 1J4, Canada
- CRIPA, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, 3200 Sicotte, St-Hyacinthe, QC, J2S 2M2, Canada
| | - Charles M Dozois
- CRIPA, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, 3200 Sicotte, St-Hyacinthe, QC, J2S 2M2, Canada
- Centre Armand-Frappier Santé Biotechnologie, Institut Nationale de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC, H7V 1B7, Canada
| | - France Daigle
- Department of Microbiology, Infectiology and Immunology, University of Montréal, 2900 Bd Édouard-Montpetit, Montreal, QC, H3T 1J4, Canada.
- CRIPA, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, 3200 Sicotte, St-Hyacinthe, QC, J2S 2M2, Canada.
| |
Collapse
|
2
|
Ndlovu L, Butaye P, Maliehe TS, Magwedere K, Mankonkwana BB, Basson AK, Ngema SS, Madoroba E. Virulence and Antimicrobial Resistance Profiling of Salmonella Serovars Recovered from Retail Poultry Offal in KwaZulu-Natal Province, South Africa. Pathogens 2023; 12:pathogens12050641. [PMID: 37242311 DOI: 10.3390/pathogens12050641] [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: 03/16/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/28/2023] Open
Abstract
As poultry organ meat is widely consumed, especially in low- and middle-income countries, there is reason to investigate it as a source of Salmonella infections in humans. Consequently, the aim of this study was to determine the prevalence, serotypes, virulence factors and antimicrobial resistance of Salmonella isolated from chicken offal from retail outlets in KwaZulu-Natal, South Africa. Samples (n = 446) were cultured for the detection of Salmonella using ISO 6579-1:2017. Presumptive Salmonella were confirmed using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. Salmonella isolates were serotyped using the Kauffmann-White-Le Minor scheme and antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion technique. A conventional PCR was used for the detection of Salmonella invA, agfA, lpfA and sivH virulence genes. Of the 446 offal samples, 13 tested positive for Salmonella (2.91%; CI = 1.6-5). The serovars included S. Enteritidis (n = 3/13), S. Mbandaka (n = 1/13), S. Infantis (n = 3/13), S. Heidelberg (n = 5/13) and S. Typhimurium (n = 1/13). Antimicrobial resistance against amoxicillin, kanamycin, chloramphenicol and oxytetracycline was found only in S. Typhimurium and S. Mbandaka. All 13 Salmonella isolates harboured invA, agfA, lpfA and sivH virulence genes. The results show low Salmonella prevalence from chicken offal. However, most serovars are known zoonotic pathogens, and multi-drug resistance was observed in some isolates. Consequently, chicken offal products need to be treated with caution to avoid zoonotic Salmonella infections.
Collapse
Affiliation(s)
- Lindokuhle Ndlovu
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - Patrick Butaye
- Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Tsolanku S Maliehe
- Department of Water and Sanitation, University of Limpopo, Polokwane 0727, South Africa
| | - Kudakwashe Magwedere
- Directorate of Veterinary Public Health, Department of Agriculture, Land Reform and Rural Development, Pretoria 0001, South Africa
| | - Bongi B Mankonkwana
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - Albertus K Basson
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - Siyanda S Ngema
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - Evelyn Madoroba
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| |
Collapse
|
3
|
Molecular Detection of Virulence Factors in Salmonella serovars Isolated from Poultry and Human Samples. Vet Med Int 2023; 2023:1875253. [PMID: 36910894 PMCID: PMC9998162 DOI: 10.1155/2023/1875253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 03/06/2023] Open
Abstract
Salmonellosis is a common infectious disease in humans caused by Salmonella spp., which in recent years has shown an increase in its incidence, with products of avian origin being a common source of transmission. To present a successful infective cycle, there are molecular mechanisms such as virulence factors that provide characteristics that facilitate survival, colonization, and damage to the host. According to this, the study aims to characterize the virulence factors of Salmonella spp. strains isolated from broilers (n = 39) and humans (n = 10). The presence of 24 virulence genes was evaluated using end-point PCR. All the strains of Salmonella spp. isolated from broiler chickens revealed presence of 7/24 (29, 16%) virulence genes (lpfA, csgA, sitC, sipB, sopB, sopE, and sivH). Regarding the strains isolated from cases of gastroenteritis in humans, all strains contained (14/24, 58, 33%) virulence genes (lpfA, csgA, pagC, msgA, spiA, sitC, iroN, sipB, orgA, hilA, sopB, sifA, avrA, and sivH). In summary, the presence of virulence genes in different strains of Salmonella isolated from broilers and humans could be described as bacteria with potential pathogenicity due to the type and number of virulence genes detected. These findings are beneficial for the pathogenic monitoring of Salmonella in Colombia.
Collapse
|
4
|
Antibiofilm Action of Plant Terpenes in Salmonella Strains: Potential Inhibitors of the Synthesis of Extracellular Polymeric Substances. Pathogens 2022; 12:pathogens12010035. [PMID: 36678383 PMCID: PMC9864247 DOI: 10.3390/pathogens12010035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 12/08/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022] Open
Abstract
Salmonella can form biofilms that contribute to its resistance in food processing environments. Biofilms are a dense population of cells that adhere to the surface, creating a matrix composed of extracellular polymeric substances (EPS) consisting mainly of polysaccharides, proteins, and eDNA. Remarkably, the secreted substances, including cellulose, curli, and colanic acid, act as protective barriers for Salmonella and contribute to its resistance and persistence when exposed to disinfectants. Conventional treatments are mostly ineffective in controlling this problem; therefore, exploring anti-biofilm molecules that minimize and eradicate Salmonella biofilms is required. The evidence indicated that terpenes effectively reduce biofilms and affect their three-dimensional structure due to the decrease in the content of EPS. Specifically, in the case of Salmonella, cellulose is an essential component in their biofilms, and its control could be through the inhibition of glycosyltransferase, the enzyme that synthesizes this polymer. The inhibition of polymeric substances secreted by Salmonella during biofilm development could be considered a target to reduce its resistance to disinfectants, and terpenes can be regarded as inhibitors of this process. However, more studies are needed to evaluate the effectiveness of these compounds against Salmonella enzymes that produce extracellular polymeric substances.
Collapse
|
5
|
Molecular Characterization of Salmonella Detected along the Broiler Production Chain in Trinidad and Tobago. Microorganisms 2022; 10:microorganisms10030570. [PMID: 35336145 PMCID: PMC8955423 DOI: 10.3390/microorganisms10030570] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 02/04/2023] Open
Abstract
This cross-sectional study determined the serovars, antimicrobial resistance genes, and virulence factors of Salmonella isolated from hatcheries, broiler farms, processing plants, and retail outlets in Trinidad and Tobago. Salmonella in silico serotyping detected 23 different serovars where Kentucky 20.5% (30/146), Javiana 19.2% (28/146), Infantis 13.7% (20/146), and Albany 8.9% (13/146) were the predominant serovars. There was a 76.0% (111/146) agreement between serotyping results using traditional conventional methods and whole-genome sequencing (WGS) in in silico analysis. In silico identification of antimicrobial resistance genes conferring resistance to aminoglycosides, cephalosporins, peptides, sulfonamides, and antiseptics were detected. Multidrug resistance (MDR) was detected in 6.8% (10/146) of the isolates of which 100% originated from broiler farms. Overall, virulence factors associated with secretion systems and fimbrial adherence determinants accounted for 69.3% (3091/4463), and 29.2% (1302/4463) counts, respectively. Ten of 20 isolates of serovar Infantis (50.0%) showed MDR and contained the blaCTX-M-65 gene. This is the first molecular characterization of Salmonella isolates detected along the entire broiler production continuum in the Caribbean region using WGS. The availability of these genomes will help future source tracking during epidemiological investigations associated with Salmonella foodborne outbreaks in the region and worldwide.
Collapse
|
6
|
Multifunctional Amyloids in the Biology of Gram-Positive Bacteria. Microorganisms 2020; 8:microorganisms8122020. [PMID: 33348645 PMCID: PMC7766987 DOI: 10.3390/microorganisms8122020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 01/18/2023] Open
Abstract
Since they were discovered, amyloids have proven to be versatile proteins able to participate in a variety of cellular functions across all kingdoms of life. This multitask trait seems to reside in their ability to coexist as monomers, aggregates or fibrillar entities, with morphological and biochemical peculiarities. It is precisely this common molecular behaviour that allows amyloids to cross react with one another, triggering heterologous aggregation. In bacteria, many of these functional amyloids are devoted to the assembly of biofilms by organizing the matrix scaffold that keeps cells together. However, consistent with their notion of multifunctional proteins, functional amyloids participate in other biological roles within the same organisms, and emerging unprecedented functions are being discovered. In this review, we focus on functional amyloids reported in gram-positive bacteria, which are diverse in their assembly mechanisms and remarkably specific in their biological functions that they perform. Finally, we consider cross-seeding between functional amyloids as an emerging theme in interspecies interactions that contributes to the diversification of bacterial biology.
Collapse
|
7
|
Kosolapova AO, Antonets KS, Belousov MV, Nizhnikov AA. Biological Functions of Prokaryotic Amyloids in Interspecies Interactions: Facts and Assumptions. Int J Mol Sci 2020; 21:E7240. [PMID: 33008049 PMCID: PMC7582709 DOI: 10.3390/ijms21197240] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023] Open
Abstract
Amyloids are fibrillar protein aggregates with an ordered spatial structure called "cross-β". While some amyloids are associated with development of approximately 50 incurable diseases of humans and animals, the others perform various crucial physiological functions. The greatest diversity of amyloids functions is identified within prokaryotic species where they, being the components of the biofilm matrix, function as adhesins, regulate the activity of toxins and virulence factors, and compose extracellular protein layers. Amyloid state is widely used by different pathogenic bacterial species in their interactions with eukaryotic organisms. These amyloids, being functional for bacteria that produce them, are associated with various bacterial infections in humans and animals. Thus, the repertoire of the disease-associated amyloids includes not only dozens of pathological amyloids of mammalian origin but also numerous microbial amyloids. Although the ability of symbiotic microorganisms to produce amyloids has recently been demonstrated, functional roles of prokaryotic amyloids in host-symbiont interactions as well as in the interspecies interactions within the prokaryotic communities remain poorly studied. Here, we summarize the current findings in the field of prokaryotic amyloids, classify different interspecies interactions where these amyloids are involved, and hypothesize about their real occurrence in nature as well as their roles in pathogenesis and symbiosis.
Collapse
Affiliation(s)
- Anastasiia O. Kosolapova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Mikhail V. Belousov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia (K.S.A.); (M.V.B.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| |
Collapse
|
8
|
Pruteanu M, Hernández Lobato JI, Stach T, Hengge R. Common plant flavonoids prevent the assembly of amyloid curli fibres and can interfere with bacterial biofilm formation. Environ Microbiol 2020; 22:5280-5299. [PMID: 32869465 DOI: 10.1111/1462-2920.15216] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/01/2023]
Abstract
Like all macroorganisms, plants have to control bacterial biofilm formation on their surfaces. On the other hand, biofilms are highly tolerant against antimicrobial agents and other stresses. Consequently, biofilms are also involved in human chronic infectious diseases, which generates a strong demand for anti-biofilm agents. Therefore, we systematically explored major plant flavonoids as putative anti-biofilm agents using different types of biofilms produced by Gram-negative and Gram-positive bacteria. In Escherichia coli macrocolony biofilms, the flavone luteolin and the flavonols myricetin, morin and quercetin were found to strongly reduce the extracellular matrix. These agents directly inhibit the assembly of amyloid curli fibres by driving CsgA subunits into an off-pathway leading to SDS-insoluble oligomers. In addition, they can interfere with cellulose production by still unknown mechanisms. Submerged biofilm formation, however, is hardly affected. Moreover, the same flavonoids tend to stimulate macrocolony and submerged biofilm formation by Pseudomonas aeruginosa. For Bacillus subtilis, the flavonone naringenin and the chalcone phloretin were found to inhibit growth. Thus, plant flavonoids are not general anti-biofilm compounds but show species-specific effects. However, based on their strong and direct anti-amyloidogenic activities, distinct plant flavonoids may provide an attractive strategy to specifically combat amyloid-based biofilms of some relevant pathogens.
Collapse
Affiliation(s)
- Mihaela Pruteanu
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | | | - Thomas Stach
- Institut für Biologie/Zoologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| |
Collapse
|
9
|
Ke PC, Zhou R, Serpell LC, Riek R, Knowles TPJ, Lashuel HA, Gazit E, Hamley IW, Davis TP, Fändrich M, Otzen DE, Chapman MR, Dobson CM, Eisenberg DS, Mezzenga R. Half a century of amyloids: past, present and future. Chem Soc Rev 2020; 49:5473-5509. [PMID: 32632432 PMCID: PMC7445747 DOI: 10.1039/c9cs00199a] [Citation(s) in RCA: 298] [Impact Index Per Article: 74.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Amyloid diseases are global epidemics with profound health, social and economic implications and yet remain without a cure. This dire situation calls for research into the origin and pathological manifestations of amyloidosis to stimulate continued development of new therapeutics. In basic science and engineering, the cross-β architecture has been a constant thread underlying the structural characteristics of pathological and functional amyloids, and realizing that amyloid structures can be both pathological and functional in nature has fuelled innovations in artificial amyloids, whose use today ranges from water purification to 3D printing. At the conclusion of a half century since Eanes and Glenner's seminal study of amyloids in humans, this review commemorates the occasion by documenting the major milestones in amyloid research to date, from the perspectives of structural biology, biophysics, medicine, microbiology, engineering and nanotechnology. We also discuss new challenges and opportunities to drive this interdisciplinary field moving forward.
Collapse
Affiliation(s)
- Pu Chun Ke
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, China
| | - Ruhong Zhou
- Institute of Quantitative Biology, Zhejiang University, Hangzhou 310058, China; Department of Chemistry, Columbia University, New York, New York, 10027, USA
| | - Louise C. Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK
| | - Roland Riek
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland
| | - Tuomas P. J. Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, CB3 0HE, Cambridge, UK
| | - Hilal A. Lashuel
- Laboratory of Molecular Neurobiology and Neuroproteomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences; Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ian W. Hamley
- School of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane Qld 4072, Australia
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | - Daniel Erik Otzen
- Department of Molecular Biology, Center for Insoluble Protein Structures (inSPIN), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Matthew R. Chapman
- Department of Molecular, Cellular and Developmental Biology, Centre for Microbial Research, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Christopher M. Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - David S. Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute and Howard Hughes Medical Institute, UCLA, Los Angeles, CA, USA
| | - Raffaele Mezzenga
- Department of Health Science & Technology, ETH Zurich, Schmelzbergstrasse 9, LFO, E23, 8092 Zurich, Switzerland
- Department of Materials, ETH Zurich, Wolfgang Pauli Strasse 10, 8093 Zurich, Switzerland
| |
Collapse
|
10
|
Sewell L, Stylianou F, Xu Y, Taylor J, Sefer L, Matthews S. NMR insights into the pre-amyloid ensemble and secretion targeting of the curli subunit CsgA. Sci Rep 2020; 10:7896. [PMID: 32398666 PMCID: PMC7217966 DOI: 10.1038/s41598-020-64135-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/08/2020] [Indexed: 01/08/2023] Open
Abstract
The biofilms of Enterobacteriaceae are fortified by assembly of curli amyloid fibres on the cell surface. Curli not only provides structural reinforcement, but also facilitates surface adhesion. To prevent toxic intracellular accumulation of amyloid precipitate, secretion of the major curli subunit, CsgA, is tightly regulated. In this work, we have employed solution state NMR spectroscopy to characterise the structural ensemble of the pre-fibrillar state of CsgA within the bacterial periplasm, and upon recruitment to the curli pore, CsgG, and the secretion chaperone, CsgE. We show that the N-terminal targeting sequence (N) of CsgA binds specifically to CsgG and that its subsequent sequestration induces a marked transition in the conformational ensemble, which is coupled to a preference for CsgE binding. These observations lead us to suggest a sequential model for binding and structural rearrangement of CsgA at the periplasmic face of the secretion machinery.
Collapse
Affiliation(s)
- Lee Sewell
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Yingqi Xu
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Jonathan Taylor
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Lea Sefer
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Steve Matthews
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK.
| |
Collapse
|
11
|
Keren-Paz A, Kolodkin-Gal I. A brick in the wall: Discovering a novel mineral component of the biofilm extracellular matrix. N Biotechnol 2020; 56:9-15. [DOI: 10.1016/j.nbt.2019.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/01/2019] [Accepted: 11/02/2019] [Indexed: 01/09/2023]
|
12
|
Mendonça EP, Melo RT, Oliveira MR, Monteiro GP, Peres PA, Fonseca BB, Giombelli A, Rossi DA. Characteristics of virulence, resistance and genetic diversity of strains of Salmonella Infantis isolated from broiler chicken in Brazil. PESQUISA VETERINÁRIA BRASILEIRA 2020. [DOI: 10.1590/1678-5150-pvb-5546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT: Salmonella Infantis is frequently associated with human infections worldwide and is transmitted by consumption of contaminated foods, particularly those of animal origin, especially the chicken meat. We aimed to evaluate virulence characteristics, antimicrobial resistance and the genetic similarity of 51 strains of S. Infantis isolated from samples of poultry origin. The strains were isolated from 2009 to 2010 in a company with full cycle of broiler’s production in the state of São Paulo, Brazil. The antimicrobial susceptibility test was performed and, by PCR, we evaluated the presence of the genes lpfA (hem-adhesion), agfA (hem-biofilm) and sefA (hem-adhesion) and resistance genes to beta-lactams (blaTEM, blaSHV, bla CTX-M and blaAmpC ). The phylogenetic relationship was determined by RAPD-PCR method. Among the drugs tested, the highest percentages of resistance were to amoxicillin (35.3%) and to sulfonamide (15.7%). Eleven antimicrobial resistance patterns were identified (A1 to A11), none of them presented a multiresistance profile (> 3 antimicrobials classes). There was 100% of positivity for the agfA gene, 92.2% for the lpfA gene, and no strain presented the sefA gene. Most of the isolates showed similarities in virulence potential, since they were simultaneously positive for two studied genes, agfA and lpfA (92.2%, 47/51). Of the 18 (35.3%) strains resistant to antimicrobials of the β-lactam class, 10 (55.5%) were positive to blaAmpC gene, five (27.8%) for blaCTX-M , two (11.1%) to blaSHV and no strain presented the blaTEM gene. The phylogenetic evaluation has shown the presence of five clusters (A, B, C, D and E) with similarity greater than 80%, and three distinct strains which were not grouped in any cluster. Cluster B grouped 33 strains, all positive for lpfA and agfA genes, from both, the broiler farming facility and the slaughterhouse, persistent throughout all the study period. This cluster also grouped 18 strains clones with genetic similarity greater than 99%, all isolated in the slaughterhouse. The presence of virulence genes associated with persistent strains clones for a long period, warns to the possibility of S. Infantis to form biofilm, and should be constantly monitored in broilers’ production chain, in order to know the profile of the strains that may contaminate the final product and evaluate the hazards that represents to public health.
Collapse
|
13
|
Bergamo G, Demoliner F, Timm CD, Carvalho NR, Helbig E, Gandra EA. Formação de biofilmes e resistência a antimicrobianos de isolados de Salmonella spp. CIÊNCIA ANIMAL BRASILEIRA 2020. [DOI: 10.1590/1809-6891v21e-48029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Resumo O presente estudo avaliou a presença de Salmonella spp. em 89 amostras de produtos cárneos comercializados na região sul do Rio Grande do Sul e, a partir dos isolados obtidos, foi verificada a capacidade de resistência a agentes antimicrobianos e de formação de biofilme em superfícies de poliestireno. Foi constatada a presença de Salmonella spp. em 19,1% das amostras avaliadas e, dos isolados obtidos, 40% mostraram resistência a pelo menos um dos agentes antimicrobianos testados e 33,3% manifestaram-se multirresistentes. Apenas o antimicrobiano amicacina (30 µg) foi eficaz na inibição de todos os isolados testados. Nenhum isolado mostrou-se capaz de formar biofilmes em superfícies de poliestireno.
Collapse
|
14
|
Webber B, Borges KA, Furian TQ, Rizzo NN, Tondo EC, Santos LRD, Rodrigues LB, Nascimento VPD. Detection of virulence genes in Salmonella Heidelberg isolated from chicken carcasses. Rev Inst Med Trop Sao Paulo 2019; 61:e36. [PMID: 31340248 PMCID: PMC6648003 DOI: 10.1590/s1678-9946201961036] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/27/2019] [Indexed: 11/22/2022] Open
Abstract
During the last years, Brazilian government control programs have detected an increase of Salmonella Heidelberg in poultry slaughterhouses a condition that poses a threat to human health However, the reasons remain unclear. Differences in genetic virulence profiles may be a possible justification. In addition, effective control of Salmonella is related to an efficient epidemiological surveillance system through genotyping techniques. In this context, the aim of this study was the detection of 24 virulence-associated genes in 126 S. Heidelberg isolates. We classified the isolates into 56 different genetic profiles. None of the isolates presented all the virulence genes. The prevalence of these genes was high in all tested samples as the lowest number of genes detected in one isolate was 10/24. The lpfA and csgA (fimbriae), invA and sivH (TTSS), and msgA and tolC (intracellular survival) genes were present in 100% of the isolates analyzed. Genes encoding effector proteins were detected in the majority of SH isolates. No single isolate had the sefA gene. The pefA gene was found in only four isolates. We have also performed a screening of genes associated with iron metabolism: 88.9% of isolates had the iroN geneand 79.4% the sitC gene . Although all the isolates belong to the same serotype, several genotypic profiles were observed. These findings suggest that there is a diversity of S. Heidelberg isolates in poultry products. The fact that a single predominant profile was not found in this study indicates the presence of variable sources of contamination caused by SH. The detection of genetic profiles of Salmonella strains can be used to determine the virulence patterns of SH isolates.
Collapse
Affiliation(s)
- Bruna Webber
- Universidade Federal do Rio Grande do Sul, Faculdade de Veterinária, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Rio Grande do Sul, Brazil
| | - Karen Apellanis Borges
- Universidade Federal do Rio Grande do Sul, Faculdade de Veterinária, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Rio Grande do Sul, Brazil
| | - Thales Quedi Furian
- Universidade Federal do Rio Grande do Sul, Faculdade de Veterinária, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Rio Grande do Sul, Brazil
| | - Natalie Nadin Rizzo
- Universidade Federal do Rio Grande do Sul, Faculdade de Veterinária, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Rio Grande do Sul, Brazil
| | - Eduardo Cesar Tondo
- Universidade Federal do Rio Grande do Sul, Instituto de Ciências e Tecnologia de Alimentos, Porto Alegre, Rio Grande do Sul, Brazil
| | | | | | - Vladimir Pinheiro do Nascimento
- Universidade Federal do Rio Grande do Sul, Faculdade de Veterinária, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Rio Grande do Sul, Brazil
| |
Collapse
|
15
|
Abstract
To interact with the external environments, bacteria often display long proteinaceous appendages on their cell surface, called pili or fimbriae. These non-flagellar thread-like structures are polymers composed of covalently or non-covalently interacting repeated pilin subunits. Distinct pilus classes can be identified on basis of their assembly pathways, including chaperone-usher pili, type V pili, type IV pili, curli and fap fibers, conjugative and type IV secretion pili, as well as sortase-mediated pili. Pili play versatile roles in bacterial physiology, and can be involved in adhesion and host cell invasion, DNA and protein secretion and uptake, biofilm formation, cell motility and more. Recent advances in structure determination of components involved in the various pilus systems has enabled a better molecular understanding of their mechanisms of assembly and function. In this chapter we describe the diversity in structure, biogenesis and function of the different pilus systems found in Gram-positive and Gram-negative bacteria, and review their potential as anti-microbial targets.
Collapse
Affiliation(s)
- Magdalena Lukaszczyk
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Brajabandhu Pradhan
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Han Remaut
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium.
| |
Collapse
|
16
|
Bacterial Amyloids: Biogenesis and Biomaterials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1174:113-159. [DOI: 10.1007/978-981-13-9791-2_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
17
|
Wang Y, Jiang J, Gao Y, Sun Y, Dai J, Wu Y, Qu D, Ma G, Fang X. Staphylococcus epidermidis small basic protein (Sbp) forms amyloid fibrils, consistent with its function as a scaffolding protein in biofilms. J Biol Chem 2018; 293:14296-14311. [PMID: 30049797 PMCID: PMC6139570 DOI: 10.1074/jbc.ra118.002448] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/24/2018] [Indexed: 12/12/2022] Open
Abstract
Biofilms are communities of microbes embedded in a microbial extracellular matrix. Their formation is considered the main virulence mechanism enabling the opportunistic bacterial pathogen Staphylococcus epidermidis to cause devastating nosocomial, implant-associated infections. Biofilms often contain proteins, and an 18-kDa protein called small basic protein (Sbp) recently was discovered in the S. epidermidis biofilm matrix and may serve as a scaffolding protein in both polysaccharide intercellular adhesin (PIA)-dependent and accumulation-associated protein (Aap)-dependent biofilm formations. In Aap-mediated biofilm formation, Sbp colocalizes with Domain-B of Aap, implying that Sbp directly interacts with Aap's Domain-B. However, the structure of Sbp and its interaction with Aap, as well as the molecular mechanism underlying Sbp's roles in biofilm formation, are incompletely understood. In this work, we used small-angle X-ray scattering (SAXS), NMR, analytical size-exclusion chromatography, and isothermal titration calorimetry analyses to determine the Sbp structure and characterize its interaction with Aap's Domain-B. We found that Sbp is monomeric and partially folded in solution, and, unexpectedly, we observed no direct interactions between Sbp and Aap Domain-B. Instead, we noted that Sbp forms amyloid fibrils both in vitro and in vivo Atomic force, transmission electron, and confocal fluorescence microscopy methods confirmed the formation of Sbp amyloid fibrils and revealed their morphology. Taken together, the Sbp amyloid fibril structures identified here may account for Sbp's role as a scaffolding protein in the S. epidermidis biofilm matrix.
Collapse
Affiliation(s)
- Yan Wang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingbo Jiang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yachao Gao
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yang Sun
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianfeng Dai
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education and Ministry of Public Health, Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai 200032, China, and
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education and Ministry of Public Health, Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai 200032, China, and
| | - Gang Ma
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Xianyang Fang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China,
| |
Collapse
|
18
|
The Production of Curli Amyloid Fibers Is Deeply Integrated into the Biology of Escherichia coli. Biomolecules 2017; 7:biom7040075. [PMID: 29088115 PMCID: PMC5745457 DOI: 10.3390/biom7040075] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/13/2017] [Accepted: 10/23/2017] [Indexed: 12/29/2022] Open
Abstract
Curli amyloid fibers are the major protein component of the extracellular matrix produced by Enterobacteriaceae during biofilm formation. Curli are required for proper biofilm development and environmental persistence by Escherichia coli. Here, we present a complete and vetted genetic analysis of functional amyloid fiber biogenesis. The Keio collection of single gene deletions was screened on Congo red indicator plates to identify E. coli mutants that had defective amyloid production. We discovered that more than three hundred gene products modulated curli production. These genes were involved in fundamental cellular processes such as regulation, environmental sensing, respiration, metabolism, cell envelope biogenesis, transport, and protein turnover. The alternative sigma factors, σS and σE, had opposing roles in curli production. Mutations that induced the σE or Cpx stress response systems had reduced curli production, while mutant strains with increased σS levels had increased curli production. Mutations in metabolic pathways, including gluconeogenesis and the biosynthesis of lipopolysaccharide (LPS), produced less curli. Regulation of the master biofilm regulator, CsgD, was diverse, and the screen revealed several proteins and small RNAs (sRNA) that regulate csgD messenger RNA (mRNA) levels. Using previously published studies, we found minimal overlap between the genes affecting curli biogenesis and genes known to impact swimming or swarming motility, underlying the distinction between motile and sessile lifestyles. Collectively, the diversity and number of elements required suggest curli production is part of a highly regulated and complex developmental pathway in E. coli.
Collapse
|
19
|
Markande AR, Nerurkar AS. Bioemulsifier (BE-AM1) produced by Solibacillus silvestris AM1 is a functional amyloid that modulates bacterial cell-surface properties. BIOFOULING 2016; 32:1153-1162. [PMID: 27669827 DOI: 10.1080/08927014.2016.1232716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
A novel estuarine bacterial strain, Solibacillus silvestris AM1, produces an extracellular, thermostable and fibrous, glycoprotein bioemulsifier (BE-AM1). The amyloid nature of the bioemulsifier (BE-AM1) was confirmed by biophysical techniques (Congo red based polarization microscopy, ThioflavinS based fluorescent microscopy, fibrous arrangement in transmission electron microscopy and secondary structure measurement by FTIR and CD spectrum analysis). Cell-bound BE-AM1 production by S. silvestris AM1 during the mid-logarithmic phase of growth coincided with a decrease in cell surface hydrophobicity, and an increase in cell autoaggregation and biofilm formation. It was observed that the total interfacial interaction energy ([Formula: see text]) for the surface of the bioemulsifier producing S. silvestris AM1 and different derivatized surfaces of polystyrene (silanized and sulfonated) was found to support biofilm formation. This study has revealed that the BE-AM1, a bacterial bioemulsifier, is a functional amyloid and has a role in biofilm formation and cell surface modulation in S. silvestris AM1.
Collapse
Affiliation(s)
- A R Markande
- a Department of Microbiology and Biotechnology Centre, Faculty of Science , The Maharaja Sayajirao University of Baroda , Vadodara , India
| | - A S Nerurkar
- a Department of Microbiology and Biotechnology Centre, Faculty of Science , The Maharaja Sayajirao University of Baroda , Vadodara , India
| |
Collapse
|
20
|
Selivanova OM, Gorbunova EY, Mustaeva LG, Grigorashvili EI, Suvorina MY, Surin AK, Galzitskaya OV. Peptide Aβ(16-25) forms nanofilms in the process of its aggregation. BIOCHEMISTRY (MOSCOW) 2016; 81:755-761. [DOI: 10.1134/s0006297916070129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
|
21
|
Taylor JD, Hawthorne WJ, Lo J, Dear A, Jain N, Meisl G, Andreasen M, Fletcher C, Koch M, Darvill N, Scull N, Escalera-Maurer A, Sefer L, Wenman R, Lambert S, Jean J, Xu Y, Turner B, Kazarian SG, Chapman MR, Bubeck D, de Simone A, Knowles TPJ, Matthews SJ. Electrostatically-guided inhibition of Curli amyloid nucleation by the CsgC-like family of chaperones. Sci Rep 2016; 6:24656. [PMID: 27098162 PMCID: PMC4838910 DOI: 10.1038/srep24656] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 03/29/2016] [Indexed: 11/16/2022] Open
Abstract
Polypeptide aggregation into amyloid is linked with several debilitating human diseases. Despite the inherent risk of aggregation-induced cytotoxicity, bacteria control the export of amyloid-prone subunits and assemble adhesive amyloid fibres during biofilm formation. An Escherichia protein, CsgC potently inhibits amyloid formation of curli amyloid proteins. Here we unlock its mechanism of action, and show that CsgC strongly inhibits primary nucleation via electrostatically-guided molecular encounters, which expands the conformational distribution of disordered curli subunits. This delays the formation of higher order intermediates and maintains amyloidogenic subunits in a secretion-competent form. New structural insight also reveal that CsgC is part of diverse family of bacterial amyloid inhibitors. Curli assembly is therefore not only arrested in the periplasm, but the preservation of conformational flexibility also enables efficient secretion to the cell surface. Understanding how bacteria safely handle amyloidogenic polypeptides contribute towards efforts to control aggregation in disease-causing amyloids and amyloid-based biotechnological applications.
Collapse
Affiliation(s)
- Jonathan D Taylor
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Joanne Lo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alexander Dear
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Neha Jain
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Georg Meisl
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Maria Andreasen
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Catherine Fletcher
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Marion Koch
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Nicholas Darvill
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Nicola Scull
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Lea Sefer
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Rosemary Wenman
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Sebastian Lambert
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Jisoo Jean
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Yingqi Xu
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Benjamin Turner
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Sergei G Kazarian
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alfonso de Simone
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Steve J Matthews
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| |
Collapse
|
22
|
Green A, Pham N, Osby K, Aram A, Claudius R, Patray S, Jayasinghe SA. Are the curli proteins CsgE and CsgF intrinsically disordered? INTRINSICALLY DISORDERED PROTEINS 2016; 4:e1130675. [PMID: 28232894 DOI: 10.1080/21690707.2015.1130675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/05/2015] [Indexed: 10/22/2022]
Abstract
Curli are a type of proteinaceous cell surface filament produced by enteric bacteria such as Escherichia and Salmonella that facilitate cell adhesion and invasion, bio-film formation, and environmental persistence. Curli assembly involves 6 proteins encoded by the curli specific genes A, B, C, E, F, and G. Although CsgA is the major structural component of curli, CsgE, and CsgF, are thought to play important chaperone like functions in the assembly of CsgA into curli. Given that some proteins with chaperone like function have been observed to contain disordered regions, sequence analysis and circular dichroism spectroscopy was used to investigate the possibility that structures of CsgE and CsgF were also disordered. Sequence analysis based on charge and hydrophobicity, as well as using the disorder prediction software PONDR, indicates that both proteins have significant regions of disorder. The secondary structure and unfolding, of CsgE and CsgF, analyzed using circular dichroism spectroscopy suggests that both proteins lack a well defined and stable structure. These observations support the hypothesis that the curli assembly proteins CsgE and CsgF are disordered proteins containing intrinsically disordered regions.
Collapse
Affiliation(s)
- Amanda Green
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Nguyen Pham
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Krystle Osby
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Alexander Aram
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Rochelle Claudius
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Sharon Patray
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| | - Sajith A Jayasinghe
- Department of Chemistry and Biochemistry, California State University San Marcos , San Marcos, CA, USA
| |
Collapse
|
23
|
Van Gerven N, Klein RD, Hultgren SJ, Remaut H. Bacterial amyloid formation: structural insights into curli biogensis. Trends Microbiol 2015; 23:693-706. [PMID: 26439293 DOI: 10.1016/j.tim.2015.07.010] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/06/2015] [Accepted: 07/22/2015] [Indexed: 01/20/2023]
Abstract
Curli are functional amyloid fibers assembled by many Gram-negative bacteria as part of an extracellular matrix that encapsulates the bacteria within a biofilm. A multicomponent secretion system ensures the safe transport of the aggregation-prone curli subunits across the periplasm and outer membrane, and coordinates subunit self-assembly into surface-attached fibers. To avoid the build-up of potentially toxic intracellular protein aggregates, the timing and location of the interactions of the different curli proteins are of paramount importance. Here we review the structural and molecular biology of curli biogenesis, with a focus on the recent breakthroughs in our understanding of subunit chaperoning and secretion. The mechanistic insight into the curli assembly pathway will provide tools for new biotechnological applications and inform the design of targeted inhibitors of amyloid polymerization and biofilm formation.
Collapse
Affiliation(s)
- Nani Van Gerven
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Roger D Klein
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University in Saint Louis School of Medicine, St Louis, MO 63110-1010, USA
| | - Scott J Hultgren
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University in Saint Louis School of Medicine, St Louis, MO 63110-1010, USA
| | - Han Remaut
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| |
Collapse
|
24
|
Ramsugit S, Pillay M. Pili of Mycobacterium tuberculosis: current knowledge and future prospects. Arch Microbiol 2015; 197:737-44. [PMID: 25975850 DOI: 10.1007/s00203-015-1117-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/02/2015] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
Many pathogenic bacteria express filamentous appendages, termed pili, on their surface. These organelles function in several important bacterial processes, including mediating bacterial interaction with, and colonization of the host, signalling events, locomotion, DNA uptake, electric conductance, and biofilm formation. In the last decade, it has been established that the tuberculosis-causing bacterium, Mycobacterium tuberculosis, produces two pili types: curli and type IV pili. In this paper, we review studies on M. tuberculosis pili, highlighting their structure and biological significance to M. tuberculosis pathogenesis, and discuss their potential as targets for therapeutic intervention and diagnostic test development.
Collapse
Affiliation(s)
- Saiyur Ramsugit
- Medical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, 1st Floor Doris Duke Medical Research Institute, Private Bag 7, Congella, Durban, 4013, South Africa
| | | |
Collapse
|
25
|
Hobley L, Harkins C, MacPhee CE, Stanley-Wall NR. Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes. FEMS Microbiol Rev 2015; 39:649-69. [PMID: 25907113 PMCID: PMC4551309 DOI: 10.1093/femsre/fuv015] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2015] [Indexed: 01/24/2023] Open
Abstract
Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars. Examining the structure and function of the biofilm extracellular matrix.
Collapse
Affiliation(s)
- Laura Hobley
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Catriona Harkins
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| |
Collapse
|
26
|
Taylor JD, Matthews SJ. New insight into the molecular control of bacterial functional amyloids. Front Cell Infect Microbiol 2015; 5:33. [PMID: 25905048 PMCID: PMC4389571 DOI: 10.3389/fcimb.2015.00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/19/2015] [Indexed: 11/16/2022] Open
Abstract
Amyloid protein structure has been discovered in a variety of functional or pathogenic contexts. What distinguishes the former from the latter is that functional amyloid systems possess dedicated molecular control systems that determine the timing, location, and structure of the fibers. Failure to guide this process can result in cytotoxicity, as observed in several pathologies like Alzheimer's and Parkinson's Disease. Many gram-negative bacteria produce an extracellular amyloid fiber known as curli via a multi-component secretion system. During this process, aggregation-prone, semi-folded curli subunits have to cross the periplasm and outer-membrane and self-assemble into surface-attached fibers. Two recent breakthroughs have provided molecular details regarding periplasmic chaperoning and subunit secretion. This review offers a combined perspective on these first mechanistic insights into the curli system.
Collapse
Affiliation(s)
- Jonathan D Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College of Science, Technology and Medicine London, UK
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College of Science, Technology and Medicine London, UK
| |
Collapse
|
27
|
The Matrix Reloaded: Probing the Extracellular Matrix Synchronizes Bacterial Communities. J Bacteriol 2015; 197:2092-2103. [PMID: 25825428 DOI: 10.1128/jb.02516-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In response to chemical communication, bacterial cells often organize themselves into complex multicellular communities that carry out specialized tasks. These communities are frequently referred to as biofilms, which involve collective behavior of different cell types. Like cells of multicellular eukaryotes, the biofilm cells are surrounded by self-produced polymers that constitute the extracellular matrix (ECM), which binds them to each other and to the surface. In multicellular eukaryotes, it has been evident for decades that cell-ECM interactions control multiple cellular processes during development. While cells, both in biofilms and in multicellular eukaryotes, are surrounded by ECM and activate various genetic programs, until recently it has been unclear whether cell-ECM interactions are recruited in bacterial communicative behaviors. In this review, we will describe the examples reported thus far for ECM involvement in control of cell behavior throughout the different stages of biofilm formation. The studies presented in this review provide a newly emerging perspective of the bacterial ECM as an active player in regulation of biofilm development.
Collapse
|
28
|
Evans ML, Chorell E, Taylor JD, Åden J, Götheson A, Li F, Koch M, Sefer L, Matthews SJ, Wittung-Stafshede P, Almqvist F, Chapman MR. The bacterial curli system possesses a potent and selective inhibitor of amyloid formation. Mol Cell 2015; 57:445-55. [PMID: 25620560 PMCID: PMC4320674 DOI: 10.1016/j.molcel.2014.12.025] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/28/2014] [Accepted: 12/16/2014] [Indexed: 12/22/2022]
Abstract
Curli are extracellular functional amyloids that are assembled by enteric bacteria during biofilm formation and host colonization. An efficient secretion system and chaperone network ensures that the major curli fiber subunit, CsgA, does not form intracellular amyloid aggregates. We discovered that the periplasmic protein CsgC was a highly effective inhibitor of CsgA amyloid formation. In the absence of CsgC, CsgA formed toxic intracellular aggregates. In vitro, CsgC inhibited CsgA amyloid formation at substoichiometric concentrations and maintained CsgA in a non-β-sheet-rich conformation. Interestingly, CsgC inhibited amyloid assembly of human α-synuclein, but not Aβ42, in vitro. We identified a common D-Q-Φ-X0,1-G-K-N-ζ-E motif in CsgC client proteins that is not found in Aβ42. CsgC is therefore both an efficient and selective amyloid inhibitor. Dedicated functional amyloid inhibitors may be a key feature that distinguishes functional amyloids from disease-associated amyloids.
Collapse
Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Erik Chorell
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Jonathan D Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Jörgen Åden
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Anna Götheson
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Fei Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Marion Koch
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Lea Sefer
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Fredrik Almqvist
- Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden; Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Matthew R Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA; Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden.
| |
Collapse
|
29
|
Moura M, Oliveira R, Melo R, Mendonça E, Fonseca B, Rossi D. Genes de virulência e diversidade genética em Salmonella spp. isoladas de amostras de origem suína. ARQ BRAS MED VET ZOO 2014. [DOI: 10.1590/1678-6809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A diversificação da produção industrial de alimentos de origem suína e o intercâmbio comercial de animais e seus derivados destinados ao consumo humano podem ser importantes disseminadores de sorovares de Salmonella spp. na cadeia alimentar. Objetivou-se avaliar em 86 cepas de Salmonella spp., isoladas em granja de terminação e no abate de suínos, a ocorrência de três genes de virulência (invA, agfA e lpfA), bem como a similaridade genética entre elas. A ocorrência do gene invA foi verificada em 100% das amostras. O gene lpfA foi detectado em 80,23% (69/86) das cepas, não foi detectado em S. Panama e estava presente em todas as cepas de S. Infantis. O gene agfA foi detectado em 63,95% (55/86) das amostras. S. Agona apresentou positividade para todos os genes de virulência estudados. A análise de homologia entre as cepas agrupou os diferentes sorovares em clusters. A similaridade foi independente do local de isolamento, o que demonstra a presença de clones ao longo da cadeia de produção e a existência de multiplicidade de fontes para a infecção dos animais, como a ração, e a contaminação cruzada das carcaças. A pesquisa de genes de virulência e a avaliação da proximidade gênica permitem a caracterização e um maior entendimento sobre cepas de Salmonella circulantes na cadeia produtiva de suínos e, assim, podem subsidiar medidas de controle durante o processo produtivo com o objetivo de garantir a saúde do consumidor.
Collapse
|
30
|
Syed AK, Boles BR. Fold modulating function: bacterial toxins to functional amyloids. Front Microbiol 2014; 5:401. [PMID: 25136340 PMCID: PMC4118032 DOI: 10.3389/fmicb.2014.00401] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/16/2014] [Indexed: 12/11/2022] Open
Abstract
Many bacteria produce cytolytic toxins that target host cells or other competing microbes. It is well known that environmental factors control toxin expression, however, recent work suggests that some bacteria manipulate the fold of these protein toxins to control their function. The β-sheet rich amyloid fold is a highly stable ordered aggregate that many toxins form in response to specific environmental conditions. When in the amyloid state, toxins become inert, losing the cytolytic activity they display in the soluble form. Emerging evidence suggest that some amyloids function as toxin storage systems until they are again needed, while other bacteria utilize amyloids as a structural matrix component of biofilms. This amyloid matrix component facilitates resistance to biofilm disruptive challenges. The bacterial amyloids discussed in this review reveal an elegant system where changes in protein fold and solubility dictate the function of proteins in response to the environment.
Collapse
Affiliation(s)
- Adnan K Syed
- Department of Molecular Cellular and Developmental Biology, University of Michigan Ann Arbor, MI, USA
| | - Blaise R Boles
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, USA
| |
Collapse
|
31
|
Evans ML, Chapman MR. Curli biogenesis: order out of disorder. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:1551-8. [PMID: 24080089 PMCID: PMC4243835 DOI: 10.1016/j.bbamcr.2013.09.010] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/18/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Many bacteria assemble extracellular amyloid fibers on their cell surface. Secretion of proteins across membranes and the assembly of complex macromolecular structures must be highly coordinated to avoid the accumulation of potentially toxic intracellular protein aggregates. Extracellular amyloid fiber assembly poses an even greater threat to cellular health due to the highly aggregative nature of amyloids and the inherent toxicity of amyloid assembly intermediates. Therefore, temporal and spatial control of amyloid protein secretion is paramount. The biogenesis and assembly of the extracellular bacterial amyloid curli is an ideal system for studying how bacteria cope with the many challenges of controlled and ordered amyloid assembly. Here, we review the recent progress in the curli field that has made curli biogenesis one of the best-understood functional amyloid assembly pathways. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
Collapse
Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | - Matthew R Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA.
| |
Collapse
|
32
|
Comparative Virulotyping of Salmonella typhi and Salmonella enteritidis. Indian J Microbiol 2013; 53:410-7. [PMID: 24426144 DOI: 10.1007/s12088-013-0407-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 04/12/2013] [Indexed: 10/26/2022] Open
Abstract
Members of Salmonella enterica are important foodborne pathogens of significant public health concern worldwide. This study aimed to determine a range of virulence genes among typhoidal (S. typhi) and non-typhoidal (S. enteritidis) strains isolated from different geographical regions and different years. A total of 87 S. typhi and 94 S. enteritidis strains were tested for presence of 22 virulence genes by employing multiplex PCR and the genetic relatedness of these strains was further characterized by REP-PCR. In S. typhi, invA, prgH, sifA, spiC, sopB, iroN, sitC, misL, pipD, cdtB, and orfL were present in all the strains, while sopE, agfC, agfA, sefC, mgtC, and sefD were present in 98.8, 97.7, 90.8, 87.4, 87.4 and 17.2 %, of the strains, respectively. No lpfA, lpfC, pefA, spvB, or spvC was detected. Meanwhile, in S. enteritidis, 15 genes, agfA, agfC, invA, lpfA, lpfC, sefD, prgH, spiC, sopB, sopE, iroN, sitC, misL, pipD, and orfL were found in all S. enteritidis strains 100 %, followed by sifA and spvC 98.9 %, pefA, spvB and mgtC 97.8 %, and sefC 90.4 %. cdtB was absent from all S. enteritidis strains tested. REP-PCR subtyped S. typhi strains into 18 REP-types and concurred with the virulotyping results in grouping the strains, while in S. enteritidis, REP-PCR subtyped the strains into eight profiles and they were poorly distinguishable between human and animal origins. The study showed that S. typhi and S. enteritidis contain a range of virulence factors associated with pathogenesis. Virulotyping is a rapid screening method to identify and profile virulence genes in Salmonella strains, and improve an understanding of potential risk for human and animal infections.
Collapse
|
33
|
Dueholm MS, Albertsen M, Otzen D, Nielsen PH. Curli functional amyloid systems are phylogenetically widespread and display large diversity in operon and protein structure. PLoS One 2012; 7:e51274. [PMID: 23251478 PMCID: PMC3521004 DOI: 10.1371/journal.pone.0051274] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/30/2012] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli and a few other members of the Enterobacteriales can produce functional amyloids known as curli. These extracellular fibrils are involved in biofilm formation and studies have shown that they may act as virulence factors during infections. It is not known whether curli fibrils are restricted to the Enterobacteriales or if they are phylogenetically widespread. The growing number of genome-sequenced bacteria spanning many phylogenetic groups allows a reliable bioinformatic investigation of the phylogenetic diversity of the curli system. Here we show that the curli system is phylogenetically much more widespread than initially assumed, spanning at least four phyla. Curli fibrils may consequently be encountered frequently in environmental as well as pathogenic biofilms, which was supported by identification of curli genes in public metagenomes from a diverse range of habitats. Identification and comparison of curli subunit (CsgA/B) homologs show that these proteins allow a high degree of freedom in their primary protein structure, although a modular structure of tightly spaced repeat regions containing conserved glutamine, asparagine and glycine residues has to be preserved. In addition, a high degree of variability within the operon structure of curli subunits between bacterial taxa suggests that the curli fibrils might have evolved to fulfill specific functions. Variations in the genetic organization of curli genes are also seen among different bacterial genera. This suggests that some genera may utilize alternative regulatory pathways for curli expression. Comparison of phylogenetic trees of Csg proteins and the 16S rRNA genes of the corresponding bacteria showed remarkably similar overall topography, suggesting that horizontal gene transfer is a minor player in the spreading of the curli system.
Collapse
Affiliation(s)
- Morten S. Dueholm
- Department of Biotechnology, Chemistry, and Environmental Engineering, Aalborg University, Aalborg, Denmark
| | - Mads Albertsen
- Department of Biotechnology, Chemistry, and Environmental Engineering, Aalborg University, Aalborg, Denmark
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Per Halkjær Nielsen
- Department of Biotechnology, Chemistry, and Environmental Engineering, Aalborg University, Aalborg, Denmark
- * E-mail:
| |
Collapse
|
34
|
Chai LC, Kong BH, Elemfareji OI, Thong KL. Variable carbon catabolism among Salmonella enterica serovar Typhi isolates. PLoS One 2012; 7:e36201. [PMID: 22662115 PMCID: PMC3360705 DOI: 10.1371/journal.pone.0036201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 04/03/2012] [Indexed: 12/22/2022] Open
Abstract
Background Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. Methodology/Principal Findings To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas oftyphoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates) was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. Conclusion The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen.
Collapse
Affiliation(s)
- Lay Ching Chai
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- Laboratory of Biomedical Science and Molecular Microbiology, Institute of Graduate Studies, University of Malaya, Kuala Lumpur, Malaysia
| | - Boon Hong Kong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- Laboratory of Biomedical Science and Molecular Microbiology, Institute of Graduate Studies, University of Malaya, Kuala Lumpur, Malaysia
| | - Omar Ismail Elemfareji
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- Laboratory of Biomedical Science and Molecular Microbiology, Institute of Graduate Studies, University of Malaya, Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- Laboratory of Biomedical Science and Molecular Microbiology, Institute of Graduate Studies, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
| |
Collapse
|
35
|
Steenackers H, Hermans K, Vanderleyden J, De Keersmaecker SC. Salmonella biofilms: An overview on occurrence, structure, regulation and eradication. Food Res Int 2012. [DOI: 10.1016/j.foodres.2011.01.038] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
36
|
Taylor JD, Zhou Y, Salgado PS, Patwardhan A, McGuffie M, Pape T, Grabe G, Ashman E, Constable SC, Simpson PJ, Lee WC, Cota E, Chapman MR, Matthews SJ. Atomic resolution insights into curli fiber biogenesis. Structure 2011; 19:1307-16. [PMID: 21893289 PMCID: PMC3173608 DOI: 10.1016/j.str.2011.05.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/26/2011] [Accepted: 05/28/2011] [Indexed: 11/24/2022]
Abstract
Bacteria produce functional amyloid fibers called curli in a controlled, noncytotoxic manner. These extracellular fimbriae enable biofilm formation and promote pathogenicity. Understanding curli biogenesis is important for appreciating microbial lifestyles and will offer clues as to how disease-associated human amyloid formation might be ameliorated. Proteins encoded by the curli specific genes (csgA-G) are required for curli production. We have determined the structure of CsgC and derived the first structural model of the outer-membrane subunit translocator CsgG. Unexpectedly, CsgC is related to the N-terminal domain of DsbD, both in structure and oxido-reductase capability. Furthermore, we show that CsgG belongs to the nascent class of helical outer-membrane macromolecular exporters. A cysteine in a CsgG transmembrane helix is a potential target of CsgC, and mutation of this residue influences curli assembly. Our study provides the first high-resolution structural insights into curli biogenesis.
Collapse
Affiliation(s)
- Jonathan D Taylor
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Evans ML, Schmidt JC, Ilbert M, Doyle SM, Quan S, Bardwell JCA, Jakob U, Wickner S, Chapman MR. E. coli chaperones DnaK, Hsp33 and Spy inhibit bacterial functional amyloid assembly. Prion 2011; 5:323-34. [PMID: 22156728 PMCID: PMC3821533 DOI: 10.4161/pri.18555] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/24/2011] [Accepted: 10/27/2011] [Indexed: 01/17/2023] Open
Abstract
Amyloid formation is an ordered aggregation process, where β-sheet rich polymers are assembled from unstructured or partially folded monomers. We examined how two Escherichia coli cytosolic chaperones, DnaK and Hsp33, and a more recently characterized periplasmic chaperone, Spy, modulate the aggregation of a functional amyloid protein, CsgA. We found that DnaK, the Hsp70 homologue in E. coli, and Hsp33, a redox-regulated holdase, potently inhibited CsgA amyloidogenesis. The Hsp33 anti-amyloidogenesis activity was oxidation dependent, as oxidized Hsp33 was significantly more efficient than reduced Hsp33 at preventing CsgA aggregation. When soluble CsgA was seeded with preformed amyloid fibers, neither Hsp33 nor DnaK were able to efficiently prevent soluble CsgA from adopting the amyloid conformation. Moreover, both DnaK and Hsp33 increased the time that CsgA was reactive with the amyloid oligomer conformation-specific A11 antibody. Since CsgA must also pass through the periplasm during secretion, we assessed the ability of the periplasmic chaperone Spy to inhibit CsgA polymerization. Like DnaK and Hsp33, Spy also inhibited CsgA polymerization in vitro. Overexpression of Spy resulted in increased chaperone activity in periplasmic extracts and in reduced curli biogenesis in vivo. We propose that DnaK, Hsp33 and Spy exert their effects during the nucleation stages of CsgA fibrillation. Thus, both housekeeping and stress induced cytosolic and periplasmic chaperones may be involved in discouraging premature CsgA interactions during curli biogenesis.
Collapse
Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Evans ML, Schmidt JC, Ilbert M, Doyle SM, Quan S, Bardwell JCA, Jakob U, Wickner S, Chapman MR. E. coli chaperones DnaK, Hsp33 and Spy inhibit bacterial functional amyloid assembly. Prion 2011. [PMID: 22156728 DOI: 10.4161/pri.5.4.18555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2022] Open
Abstract
Amyloid formation is an ordered aggregation process, where β-sheet rich polymers are assembled from unstructured or partially folded monomers. We examined how two Escherichia coli cytosolic chaperones, DnaK and Hsp33, and a more recently characterized periplasmic chaperone, Spy, modulate the aggregation of a functional amyloid protein, CsgA. We found that DnaK, the Hsp70 homologue in E. coli, and Hsp33, a redox-regulated holdase, potently inhibited CsgA amyloidogenesis. The Hsp33 anti-amyloidogenesis activity was oxidation dependent, as oxidized Hsp33 was significantly more efficient than reduced Hsp33 at preventing CsgA aggregation. When soluble CsgA was seeded with preformed amyloid fibers, neither Hsp33 nor DnaK were able to efficiently prevent soluble CsgA from adopting the amyloid conformation. Moreover, both DnaK and Hsp33 increased the time that CsgA was reactive with the amyloid oligomer conformation-specific A11 antibody. Since CsgA must also pass through the periplasm during secretion, we assessed the ability of the periplasmic chaperone Spy to inhibit CsgA polymerization. Like DnaK and Hsp33, Spy also inhibited CsgA polymerization in vitro. Overexpression of Spy resulted in increased chaperone activity in periplasmic extracts and in reduced curli biogenesis in vivo. We propose that DnaK, Hsp33 and Spy exert their effects during the nucleation stages of CsgA fibrillation. Thus, both housekeeping and stress induced cytosolic and periplasmic chaperones may be involved in discouraging premature CsgA interactions during curli biogenesis.
Collapse
Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Nenninger AA, Robinson LS, Hammer ND, Epstein EA, Badtke MP, Hultgren SJ, Chapman MR. CsgE is a curli secretion specificity factor that prevents amyloid fibre aggregation. Mol Microbiol 2011; 81:486-99. [PMID: 21645131 PMCID: PMC3134098 DOI: 10.1111/j.1365-2958.2011.07706.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Curli are extracellular amyloid fibres produced by Escherichia coli that are critical for biofilm formation and adhesion to biotic and abiotic surfaces. CsgA and CsgB are the major and minor curli subunits, respectively, while CsgE, CsgF and CsgG direct the extracellular localization and assembly of curli subunits into fibres. The secretion and stability of CsgA and CsgB are dependent on the outer membrane lipoprotein CsgG. Here, we identified functional interactions between CsgG and CsgE during curli secretion. We discovered that CsgG overexpression restored curli production to a csgE strain under curli-inducing conditions. In antibiotic sensitivity and protein secretion assays, CsgG expression alone allowed translocation of erythromycin and small periplasmic proteins across the outer membrane. Coexpression of CsgE with CsgG blocked non-specific protein and antibiotic passage across the outer membrane. However, CsgE did not block secretion of proteins containing a 22-amino-acid putative outer membrane secretion signal of CsgA (A22). Finally, using purified proteins, we found that CsgE prohibited the self-assembly of CsgA into amyloid fibres. Collectively, these data indicate that CsgE provides substrate specificity to the curli secretion pore CsgG, and acts directly on the secretion substrate CsgA to prevent premature subunit assembly.
Collapse
Affiliation(s)
- Ashley A. Nenninger
- Department of Molecular Microbiology and Microbial Pathogenesis Washington University School of Medicine, Campus Box 8230 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Lloyd S. Robinson
- Department of Molecular Microbiology and Microbial Pathogenesis Washington University School of Medicine, Campus Box 8230 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Neal D. Hammer
- Department of Molecular, Cellular and Developmental Biology University of Michigan, Ann Arbor 830 North University, Ann Arbor, MI 48109, USA
| | - Elisabeth Ashman Epstein
- Department of Molecular, Cellular and Developmental Biology University of Michigan, Ann Arbor 830 North University, Ann Arbor, MI 48109, USA
| | - Matthew P. Badtke
- Department of Molecular, Cellular and Developmental Biology University of Michigan, Ann Arbor 830 North University, Ann Arbor, MI 48109, USA
| | - Scott J. Hultgren
- Department of Molecular Microbiology and Microbial Pathogenesis Washington University School of Medicine, Campus Box 8230 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Matthew R. Chapman
- Department of Molecular, Cellular and Developmental Biology University of Michigan, Ann Arbor 830 North University, Ann Arbor, MI 48109, USA
| |
Collapse
|
40
|
Chattopadhyay D, Carey AJ, Caliot E, Webb RI, Layton JR, Wang Y, Bohnsack JF, Adderson EE, Ulett GC. Phylogenetic lineage and pilus protein Spb1/SAN1518 affect opsonin-independent phagocytosis and intracellular survival of Group B Streptococcus. Microbes Infect 2011; 13:369-382. [PMID: 21238599 PMCID: PMC4500112 DOI: 10.1016/j.micinf.2010.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 12/19/2010] [Accepted: 12/21/2010] [Indexed: 11/20/2022]
Abstract
Opsonin-independent phagocytosis of Group B Streptococcus (GBS) is important in defense against neonatal GBS infections. A recent study indicated a role for GBS pilus in macrophage phagocytosis (Maisey et al Faseb J 22 2008 1715-24). We studied 163 isolates from different phylogenetic backgrounds and those possessing or lacking the gene encoding the pilus backbone protein, Spb1 (SAN1518, PI-2b) and spb1-deficient mutants of wild-type (WT) serotype III-3 GBS 874391 in non-opsonic phagocytosis assays using J774A.1 macrophages. Numbers of GBS phagocytosed differed up to 23-fold depending on phylogenetic background; isolates possessing spb1 were phagocytosed more than isolates lacking spb1. Comparing WT GBS and isogenic spb1-deficient mutants showed WT was phagocytosed better compared to mutants; Spb1 also enhanced intracellular survival as mutants were killed more efficiently. Complementation of mutants restored phagocytosis and resistance to killing in J774A.1 macrophages. Spb1 antiserum revealed surface expression in WT GBS and spatial distribution relative to capsular polysaccharide. spb1 did not affect macrophage nitric oxide and TNF-alpha responses; differences in phagocytosis did not correlate with N-acetyl d-glucosamine (from GBS cell-wall) according to enzyme-linked lectin-sorbent assay. Together, these findings support a role for phylogenetic lineage and Spb1 in opsonin-independent phagocytosis and intracellular survival of GBS in J774A.1 macrophages.
Collapse
Affiliation(s)
- Debasish Chattopadhyay
- Department of Microbiology, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
| | - Alison J. Carey
- School of Medical Sciences and Griffith Health Institute, Griffith University, Gold Coast QLD Australia 4222
| | - Elise Caliot
- Unité de Biologie des Bactéries Pathogènes à Gram Positif, Institut Pasteur, 25-28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Richard I. Webb
- Centre for Microscopy and Microanalysis, University of Queensland, Australia 4072
| | - James R. Layton
- Department of Medicine, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
| | - Yan Wang
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis TN 38105
| | - John F. Bohnsack
- Departments of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City UT 84136
| | - Elisabeth E. Adderson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis TN 38105
| | - Glen C. Ulett
- Department of Microbiology, University of Alabama at Birmingham, 845 19 Street South, BBRB 658, Birmingham AL 35294
- School of Medical Sciences and Griffith Health Institute, Griffith University, Gold Coast QLD Australia 4222
| |
Collapse
|
41
|
Morris VK, Ren Q, Macindoe I, Kwan AH, Byrne N, Sunde M. Recruitment of class I hydrophobins to the air:water interface initiates a multi-step process of functional amyloid formation. J Biol Chem 2011; 286:15955-63. [PMID: 21454575 DOI: 10.1074/jbc.m110.214197] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class I fungal hydrophobins form amphipathic monolayers composed of amyloid rodlets. This is a remarkable case of functional amyloid formation in that a hydrophobic:hydrophilic interface is required to trigger the self-assembly of the proteins. The mechanism of rodlet formation and the role of the interface in this process have not been well understood. Here, we have studied the effect of a range of additives, including ionic liquids, alcohols, and detergents, on rodlet formation by two class I hydrophobins, EAS and DewA. Although the conformation of the hydrophobins in these different solutions is not altered, we observe that the rate of rodlet formation is slowed as the surface tension of the solution is decreased, regardless of the nature of the additive. These results suggest that interface properties are of critical importance for the recruitment, alignment, and structural rearrangement of the amphipathic hydrophobin monomers. This work gives insight into the forces that drive macromolecular assembly of this unique family of proteins and allows us to propose a three-stage model for the interface-driven formation of rodlets.
Collapse
Affiliation(s)
- Vanessa K Morris
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | | | | | | | | | | |
Collapse
|
42
|
More than one way to control hair growth: regulatory mechanisms in enterobacteria that affect fimbriae assembled by the chaperone/usher pathway. J Bacteriol 2011; 193:2081-8. [PMID: 21398554 DOI: 10.1128/jb.00071-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many gram-negative enterobacteria produce surface-associated fimbriae that facilitate attachment and adherence to eucaryotic cells and tissues. These organelles are believed to play an important role during infection by enabling bacteria to colonize specific niches within their hosts. One class of these fimbriae is assembled using a periplasmic chaperone and membrane-associated scaffolding protein that has been referred to as an usher because of its function in fimbrial biogenesis. The presence of multiple types of fimbriae assembled by the chaperone/usher pathway can be found both within a single bacterial species and also among different genera. One way of controlling fimbrial assembly in these bacteria is at the genetic level by positively or negatively regulating fimbrial gene expression. This minireview considers the mechanisms that have been described to control fimbrial gene expression and uses specific examples to demonstrate both unique and shared properties of such regulatory mechanisms.
Collapse
|
43
|
Van Gerven N, Waksman G, Remaut H. Pili and flagella biology, structure, and biotechnological applications. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 103:21-72. [PMID: 21999994 DOI: 10.1016/b978-0-12-415906-8.00005-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria and Archaea expose on their outer surfaces a variety of thread-like proteinaceous organelles with which they interact with their environments. These structures are repetitive assemblies of covalently or non-covalently linked protein subunits, organized into filamentous polymers known as pili ("hair"), flagella ("whips") or injectisomes ("needles"). They serve different roles in cell motility, adhesion and host invasion, protein and DNA secretion and uptake, conductance, or cellular encapsulation. Here we describe the functional, morphological and genetic diversity of these bacterial filamentous protein structures. The organized, multi-copy build-up and/or the natural function of pili and flagella have lead to their biotechnological application as display and secretion tools, as therapeutic targets or as molecular motors. We review the documented and potential technological exploitation of bacterial surface filaments in light of their structural and functional traits.
Collapse
Affiliation(s)
- Nani Van Gerven
- Structural & Molecular Microbiology, VIB/Vrije Universiteit Brussel, Brussels, Belgium
| | | | | |
Collapse
|
44
|
Salgado PS, Taylor JD, Cota E, Matthews SJ. Extending the usability of the phasing power of diselenide bonds: SeCys SAD phasing of CsgC using a non-auxotrophic strain. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2011; 67:8-13. [PMID: 21206057 PMCID: PMC3522112 DOI: 10.1107/s0907444910042022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 10/16/2010] [Indexed: 11/10/2022]
Abstract
The CsgC protein is a component of the curli system in Escherichia coli. Reported here is the successful incorporation of selenocysteine (SeCys) and selenomethionine (SeMet) into recombinant CsgC, yielding derivatized crystals suitable for structural determination. Unlike in previous reports, a standard autotrophic expression strain was used and only single-wavelength anomalous dispersion (SAD) data were required for successful phasing. The level of SeCys/SeMet incorporation was estimated by mass spectrometry to be about 80%. The native protein crystallized in two different crystal forms (form 1 belonging to space group C222(1) and form 2 belonging to space group C2), which diffracted to 2.4 and 2.0 Å resolution, respectively, whilst Se-derivatized protein crystallized in space group C2 and diffracted to 1.7 Å resolution. The Se-derivatized crystals are suitable for SAD structure determination using only the anomalous signal derived from the SeCys residues. These results extend the usability of SeCys labelling to more general and less favourable cases, rendering it a suitable alternative to traditional phasing approaches.
Collapse
Affiliation(s)
- Paula S. Salgado
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Jonathan D. Taylor
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Ernesto Cota
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Steve J. Matthews
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| |
Collapse
|
45
|
Borsoi A, Santin E, Santos LR, Salle CTP, Moraes HLS, Nascimento VP. Inoculation of newly hatched broiler chicks with two Brazilian isolates of Salmonella Heidelberg strains with different virulence gene profiles, antimicrobial resistance, and pulsed field gel electrophoresis patterns to intestinal changes evaluation. Poult Sci 2009; 88:750-8. [PMID: 19276418 DOI: 10.3382/ps.2008-00466] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella Heidelberg is one of the 3 most frequently isolated serovars from human Salmonella cases in Canada, and the fourth most commonly reported Salmonella serovar in human foodborne disease cases in the United States. Since 1962, Salmonella Heidelberg has been isolated and reported in poultry and poultry products in Brazil. The poultry industry has focused efforts on reducing salmonellae incidence in live production in an effort to reduce Salmonella in the processing plant. A better understanding of the initial infection in chicks could provide approaches to control Salmonella contamination. The objective of the present study was to evaluate 2 Salmonella Heidelberg strains that differed in the presence of virulence genes invA, agfA, and lpfA; antimicrobial resistance profiles; and epidemiologic profiles on aspects of pathogenicity and intestinal morphology. Newly hatched broiler chicks were inoculated with 2 strains (SH23 and SH35) of Salmonella Heidelberg and cecal morphometry, histopathology, electron microscopy, and bacterial counts in the liver and cecum were assessed. The SH23 and SH35 strains resulted in different changes in villi height and crypt depth and inflammatory cell infiltration in the cecum. The SH35 group had higher liver and cecum bacterial cell counts when compared with SH23 strains.
Collapse
Affiliation(s)
- A Borsoi
- Centre for Diagnostics and Research in Avian Pathology, Faculty of Veterinary Medicine, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 8824, Agronomia, Porto Alegre, Rio Grande do Sul, Brazil, 91546-000.
| | | | | | | | | | | |
Collapse
|
46
|
Architectures and biogenesis of non-flagellar protein appendages in Gram-negative bacteria. EMBO J 2009; 27:2271-80. [PMID: 18668121 PMCID: PMC2500206 DOI: 10.1038/emboj.2008.155] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 07/07/2008] [Indexed: 11/22/2022] Open
Abstract
Bacteria commonly expose non-flagellar proteinaceous appendages on their outer surfaces. These extracellular structures, called pili or fimbriae, are employed in attachment and invasion, biofilm formation, cell motility or protein and DNA transport across membranes. Over the past 15 years, the power of molecular and structural techniques has revolutionalized our understanding of the biogenesis, structure, function and mode of action of these bacterial organelles. Here, we review the five known classes of Gram-negative non-flagellar appendages from a biosynthetic and structural point of view.
Collapse
|
47
|
Spatial clustering of the curlin secretion lipoprotein requires curli fiber assembly. J Bacteriol 2008; 191:608-15. [PMID: 19011034 DOI: 10.1128/jb.01244-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Gram-negative bacteria assemble functional amyloid surface fibers called curli. CsgB nucleates the major curli subunit protein, CsgA, into a self-propagating amyloid fiber on the cell surface. The CsgG lipoprotein is sufficient for curlin transport across the outer membrane and is hypothesized to be the central molecule of the curli fiber secretion and assembly complex. We tested the hypothesis that the curli secretion protein, CsgG, was restricted to certain areas of the cell to promote the interaction of CsgA and CsgB during curli assembly. Here, electron microscopic analysis of curli-producing strains showed that relatively few cells in the population contacted curli fibers and that curli emanated from spatially discrete points on the cell surface. Microscopic analysis revealed that CsgG was surface exposed and spatially clustered around curli fibers. CsgG localization to the outer membrane and exposure of the surface domain were not dependent on any other csg-encoded protein, but the clustering of CsgG required the csg-encoded proteins CsgE, CsgF, CsgA, and CsgB. CsgG formed stable oligomers in all the csg mutant strains, but these oligomers were distinct from the CsgG complexes assembled in wild-type cells. Finally, we found that efficient fiber assembly was required for the spatial clustering of CsgG. These results suggest a new model where curli fiber formation is spatially coordinated with the CsgG assembly apparatus.
Collapse
|
48
|
Epstein EA, Chapman MR. Polymerizing the fibre between bacteria and host cells: the biogenesis of functional amyloid fibres. Cell Microbiol 2008; 10:1413-20. [PMID: 18373633 DOI: 10.1111/j.1462-5822.2008.01148.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Amyloid fibres are proteinaceous aggregates associated with several human diseases, including Alzheimer's, Huntington's and Creutzfeldt Jakob's. Disease-associated amyloid formation is the result of proteins that misfold and aggregate into beta sheet-rich fibre polymers. Cellular toxicity is readily associated with amyloidogenesis, although the molecular mechanism of toxicity remains unknown. Recently, a new class of 'functional' amyloid fibres was discovered that demonstrates that amyloids can be utilized as a productive part of cellular biology. These functional amyloids will provide unique insights into how amyloid formation can be controlled and made less cytotoxic. Bacteria produce some of the best-characterized functional amyloids, including a surface amyloid fibre called curli. Assembled by enteric bacteria, curli fibres mediate attachment to surfaces and host tissues. Some bacterial amyloids, like harpins and microcinE492, have exploited amyloid toxicity in a directed and functional manner. Here, we review and discuss the functional amyloids assembled by bacteria. Special emphasis will be paid to the biology of functional amyloid synthesis and the connections between bacterial physiology and pathology.
Collapse
Affiliation(s)
- Elisabeth Ashman Epstein
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | | |
Collapse
|