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Yazıcı BC, Bakhedda N, Akçelik N. Effect of nisin and p-coumaric acid on autoinducer-2 activity, biofilm formation, and sprE expression of Enterococcus faecalis. Braz J Microbiol 2023; 54:601-608. [PMID: 36930448 PMCID: PMC10234943 DOI: 10.1007/s42770-023-00946-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: 06/27/2022] [Accepted: 03/02/2023] [Indexed: 03/18/2023] Open
Abstract
Quorum sensing (QS) is an inter- and intracellular communication mechanism that regulates gene expression in response to population size. Autoinducer-2 (AI-2) signaling is a QS signaling molecule common to both Gram-negative and Gram-positive bacteria. Enterococcus faecalis is one of the leading causes of nosocomial infections worldwide. There has been an increasing interest in controlling infectious diseases through targeting the QS mechanism using natural compounds. This study aimed to investigate the effect of nisin and p-coumaric acid (pCA), on biofilm formation and AI-2 signaling in E. faecalis. Their effect on the expression of the QS-regulated virulence encoding gene sprE was also investigated. Nisin exhibited a MIC ranging from 0.25 to 0.5 mg/mL, while the MIC of pCA was 1 mg/mL. The luminescence-based response of the reporter strain Vibrio harveyi BB170 was used to determine AI-2 activity in E. faecalis strains. Nisin was not effective in inhibiting AI-2 activity, while pCA reduced AI-2 activity by ≥ 60%. Moreover, pCA and nisin combination showed higher inhibitory effect on biofilm formation of E. faecalis, compared to the treatment of pCA or nisin alone. qRT-PCR analysis showed that nisin alone and the combination of nisin and pCA, at their MIC values, led to a 32.78- and 40.22-fold decrease in sprE gene expression, respectively, while pCA alone did not have a significant effect. Considering the demand to explore new therapeutic avenues for infectious bacteria, this study was the first to report that pCA can act like a quorum sensing inhibitor (QSI) against AI-2 signaling in E. faecalis.
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Affiliation(s)
| | | | - Nefise Akçelik
- Biotechnology Institute, Ankara University, Ankara, Turkey.
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2
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Autoinducer-2 and bile salts induce c-di-GMP synthesis to repress the T3SS via a T3SS chaperone. Nat Commun 2022; 13:6684. [PMID: 36335118 PMCID: PMC9637222 DOI: 10.1038/s41467-022-34607-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 10/31/2022] [Indexed: 11/07/2022] Open
Abstract
Cyclic di-GMP (c-di-GMP) transduces extracellular stimuli into intracellular responses, coordinating a plethora of important biological processes. Low levels of c-di-GMP are often associated with highly virulent behavior that depends on the type III secretion system (T3SS) effectors encoded, whereas elevated levels of c-di-GMP lead to the repression of T3SSs. However, extracellular signals that modulate c-di-GMP metabolism to control T3SSs and c-di-GMP effectors that relay environmental stimuli to changes in T3SS activity remain largely obscure. Here, we show that the quorum sensing signal autoinducer-2 (AI-2) induces c-di-GMP synthesis via a GAPES1 domain-containing diguanylate cyclase (DGC) YeaJ to repress T3SS-1 gene expression in Salmonella enterica serovar Typhimurium. YeaJ homologs capable of sensing AI-2 are present in many other species belonging to Enterobacterales. We also reveal that taurocholate and taurodeoxycholate bind to the sensory domain of the DGC YedQ to induce intracellular accumulation of c-di-GMP, thus repressing the expression of T3SS-1 genes. Further, we find that c-di-GMP negatively controls the function of T3SSs through binding to the widely conserved CesD/SycD/LcrH family of T3SS chaperones. Our results support a model in which bacteria sense changes in population density and host-derived cues to regulate c-di-GMP synthesis, thereby modulating the activity of T3SSs via a c-di-GMP-responsive T3SS chaperone.
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3
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Qi Z, Liu C. Metabolic characteristics and markers in viable but nonculturable state of Pseudomonas aeruginosa induced by chlorine stress. ENVIRONMENTAL RESEARCH 2022; 214:114111. [PMID: 35987374 DOI: 10.1016/j.envres.2022.114111] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/19/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Many Gram-negative pathogens enter the viable but nonculturable (VBNC) state to resist external environmental stress (such as disinfection). However, little is known about the metabolic properties, especially for the metabolic markers, of VBNC bacteria, which impedes the development of efficient disinfection technologies and causes more potential health risks. In this study, we analyzed the metabolic characteristics of chlorine stress-induced VBNC Pseudomonas aeruginosa at the population and single-cell levels. The overall metabolic activity of VBNC bacteria showed a downward trend, but the glyoxylate cycle, fatty acid and glycerophospholipid metabolism pathways were up-regulated. Based on the metabolic profiles of VBNC bacteria, nine metabolic markers (pyruvate, glyoxylate, guanine, glutamate, sn glycero-3-phos-phocholine, fatty acid, D-alanine, glutathione, N-Butanoyl-D-homoserine lactone) were determined. The results of single-cell Raman spectroscopy showed that the metabolic activity of VBNC bacteria was significantly reduced, but showed more significant metabolic heterogeneity. The redshift of the Raman peaks of 15N and 13C labeled VBNC bacteria was significantly weaker than that of the culturable bacteria, suggesting that the VBNC bacteria have a reduced ability to synthesize proteins, nucleotides, phospholipids, and carbohydrates. The result of this study can help to better understand the metabolic mechanisms and energy management strategy of VBNC bacteria, to achieve precise identification and effective control of VBNC bacteria.
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Affiliation(s)
- Zheng Qi
- School of Environmental Science and Engineering, Shandong Key Laboratory of Environmental Processes and Health, China-America CRC for Environment & Health of Shandong Province, Shandong University, 72# Jimo Binhai Road, Qingdao, Shandong, 266237, PR China
| | - Chunguang Liu
- School of Environmental Science and Engineering, Shandong Key Laboratory of Environmental Processes and Health, China-America CRC for Environment & Health of Shandong Province, Shandong University, 72# Jimo Binhai Road, Qingdao, Shandong, 266237, PR China; Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangdong Province, PR China.
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4
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Akçelik N, Akçelik M. What makes another life possible in bacteria? Global regulators as architects of bacterial biofilms. World J Microbiol Biotechnol 2022; 38:236. [PMID: 36229744 DOI: 10.1007/s11274-022-03376-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/02/2022] [Indexed: 10/17/2022]
Abstract
Biofilm structures are the main mode of evolutionary reproductive adaptation of bacteria, and even these features alone, are sufficient to make them the focus of genetic and physiological studies. As this life form is a multicellular-like life form coordinated by genetic and physiological programming, it is quite different from the planktonic form. In bacterial biofilms, which are often composed of more than one species in nature, there is a clear division of labor, nutrient channels, and a language (signaling) established between the cells forming the biofilm. On the other hand, biofilms, especially formed by pathogens, cause important industrial and clinical problems due to their high resistance to environmental stress conditions. Obtaining new data on the molecular basis of bacterial evolution and understanding the intra- and inter-species ecosystem relations in this context, as well as finding permanent solutions to the serious problems they create, are directly related to a detailed understanding of the genetic regulation of bacterial biofilm structures. Today, it is becoming increasingly certain that environmental signals effective in the transition from planktonic form to biofilm form and their receptor/response molecules are generally managed by similar systems and global regulator molecules in bacteria. In this sense; Besides the quorum sensing (QS) systems, cyclic adenosine monophosphate-catabolite suppressor protein (cAMP-CRP) and bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-GMP) signaling molecules are of critical importance. In this review article, current information on bacterial biofilms is summarized and interpreted based on this framework.
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Affiliation(s)
- Nefise Akçelik
- Biotechnology Institute, Ankara University, Keçiören, 06135, Ankara, Turkey.
| | - Mustafa Akçelik
- Department of Biology, Faculty of Science, Ankara University, 06100, Ankara, Turkey
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He S, Zhan Z, Shi C, Wang S, Shi X. Ethanol at Subinhibitory Concentrations Enhances Biofilm Formation in Salmonella Enteritidis. Foods 2022; 11:foods11152237. [PMID: 35954005 PMCID: PMC9367854 DOI: 10.3390/foods11152237] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 12/29/2022] Open
Abstract
The survival of Salmonella Enteritidis in the food chain is relevant to its biofilm formation capacity, which is influenced by suboptimal environmental conditions. Here, biofilm formation pattern of this bacterium was assessed in the presence of ethanol at sub-minimal inhibitory concentrations (sub-MICs) by microtiter plate assays, cell characteristic analyses, and gene expression tests. It was observed that ethanol at subinhibitory concentrations (1/4 MIC, 2.5%; 1/2 MIC, 5.0%) was able to stimulate biofilm formation in S. Enteritidis. The OD595 value (optical density at 595 nm) used to quantify biofilm production was increased from 0.14 in control groups to 0.36 and 0.63 under 2.5% and 5.0% ethanol stresses, respectively. Ethanol was also shown to reduce bacterial swimming motility and enhance cell auto-aggregation ability. However, other cell characteristics such as swarming activity, initial attachment and cell surface hydrophobicity were not remarkedly impacted by ethanol. Reverse transcription quantitative real-time PCR (RT-qPCR) analysis further revealed that the luxS gene belonging to a quorum-sensing system was upregulated by 2.49- and 10.08-fold in the presence of 2.5% and 5.0% ethanol, respectively. The relative expression level of other biofilm-related genes (adrA, csgB, csgD, and sdiA) and sRNAs (ArcZ, CsrB, OxyS, and SroC) did not obviously change. Taken together, these findings suggest that decrease in swimming motility and increase in cell auto-aggregation and quorum sensing may result in the enhancement of biofilm formation by S. Enteritidis under sublethal ethanol stress.
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Affiliation(s)
- Shoukui He
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China; (S.H.); (Z.Z.); (C.S.)
| | - Zeqiang Zhan
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China; (S.H.); (Z.Z.); (C.S.)
| | - Chunlei Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China; (S.H.); (Z.Z.); (C.S.)
| | - Siyun Wang
- Food, Nutrition and Health, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
| | - Xianming Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China; (S.H.); (Z.Z.); (C.S.)
- Correspondence:
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Sionov RV, Steinberg D. Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:1239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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Affiliation(s)
- Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Institute of Biomedical and Oral Research, The Faculty of Dental Medicine, Hadassah Medical School, The Hebrew University, Jerusalem 9112102, Israel;
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Jahan F, Chinni SV, Samuggam S, Reddy LV, Solayappan M, Su Yin L. The Complex Mechanism of the Salmonella typhi Biofilm Formation That Facilitates Pathogenicity: A Review. Int J Mol Sci 2022; 23:6462. [PMID: 35742906 PMCID: PMC9223757 DOI: 10.3390/ijms23126462] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/31/2022] [Accepted: 06/07/2022] [Indexed: 02/01/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. typhi) is an intracellular pathogen belonging to the Enterobacteriaceae family, where biofilm (aggregation and colonization of cells) formation is one of their advantageous traits. Salmonella typhi is the causative agent of typhoid fever in the human body and is exceptionally host specific. It is transmitted through the fecal-oral route by consuming contaminated food or water. This subspecies is quite intelligent to evade the innate detection and immune response of the host body, leading to systemic dissemination. Consequently, during the period of illness, the gallbladder becomes a harbor and may develop antibiotic resistance. Afterwards, they start contributing to the continuous damage of epithelium cells and make the host asymptomatic and potential carriers of this pathogen for an extended period. Statistically, almost 5% of infected people with Salmonella typhi become chronic carriers and are ready to contribute to future transmission by biofilm formation. Biofilm development is already recognized to link with pathogenicity and plays a crucial role in persistency within the human body. This review seeks to discuss some of the crucial factors related to biofilm development and its mechanism of interaction causing pathogenicity. Understanding the connections between these things will open up a new avenue for finding therapeutic approaches to combat pathogenicity.
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Affiliation(s)
- Fahmida Jahan
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Bedong 08100, Kedah, Malaysia; (F.J.); (S.S.); (M.S.)
| | - Suresh V. Chinni
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Bedong 08100, Kedah, Malaysia; (F.J.); (S.S.); (M.S.)
- Biochemistry Unit, Faculty of Medicine, Bioscience, and Nursing, MAHSA University, Jenjarom 42610, Selangor, Malaysia
| | - Sumitha Samuggam
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Bedong 08100, Kedah, Malaysia; (F.J.); (S.S.); (M.S.)
| | | | - Maheswaran Solayappan
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Bedong 08100, Kedah, Malaysia; (F.J.); (S.S.); (M.S.)
| | - Lee Su Yin
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Bedong 08100, Kedah, Malaysia; (F.J.); (S.S.); (M.S.)
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8
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Marmion M, Macori G, Whyte P, Scannell AGM. Stress response modulation: the key to survival of pathogenic and spoilage bacteria during poultry processing. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35451951 DOI: 10.1099/mic.0.001184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The control of bacterial contaminants on meat is a key area of interest in the food industry. Bacteria are exposed to a variety of stresses during broiler processing which challenge bacterial structures and metabolic pathways causing death or sublethal injury. To counter these stresses, bacteria possess robust response systems that can induce shifts in the transcriptome and proteome to enable survival. Effective adaptive responses, such as biofilm formation, shock protein production and metabolic flexibility, require rapid induction and implementation at a cellular and community level to facilitate bacterial survival in adverse conditions. This review aims to provide an overview of the scientific literature pertaining to the regulation of complex adaptive processes used by bacteria to survive the processing environment, with particular focus on species that impact the quality and safety of poultry products like Campylobacter spp., Salmonella enterica and Pseudomonas spp.
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Affiliation(s)
- Maitiú Marmion
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland
| | - Guerrino Macori
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland
| | - Paul Whyte
- UCD School of Veterinary Medicine, Belfield, Dublin 4, D04V4W8, Ireland
| | - Amalia G M Scannell
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Institute of Food and Health, Belfield, Dublin 4, D04V4W8, Ireland
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9
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Algarni S, Ricke SC, Foley SL, Han J. The Dynamics of the Antimicrobial Resistance Mobilome of Salmonella enterica and Related Enteric Bacteria. Front Microbiol 2022; 13:859854. [PMID: 35432284 PMCID: PMC9008345 DOI: 10.3389/fmicb.2022.859854] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/07/2022] [Indexed: 12/31/2022] Open
Abstract
The foodborne pathogen Salmonella enterica is considered a global public health risk. Salmonella enterica isolates can develop resistance to several antimicrobial drugs due to the rapid spread of antimicrobial resistance (AMR) genes, thus increasing the impact on hospitalization and treatment costs, as well as the healthcare system. Mobile genetic elements (MGEs) play key roles in the dissemination of AMR genes in S. enterica isolates. Multiple phenotypic and molecular techniques have been utilized to better understand the biology and epidemiology of plasmids including DNA sequence analyses, whole genome sequencing (WGS), incompatibility typing, and conjugation studies of plasmids from S. enterica and related species. Focusing on the dynamics of AMR genes is critical for identification and verification of emerging multidrug resistance. The aim of this review is to highlight the updated knowledge of AMR genes in the mobilome of Salmonella and related enteric bacteria. The mobilome is a term defined as all MGEs, including plasmids, transposons, insertion sequences (ISs), gene cassettes, integrons, and resistance islands, that contribute to the potential spread of genes in an organism, including S. enterica isolates and related species, which are the focus of this review.
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Affiliation(s)
- Suad Algarni
- Division of Microbiology, FDA National Center for Toxicological Research, Jefferson, AR, United States
- Cellular and Molecular Biology Graduate Program, University of Arkansas, Fayetteville, AR, United States
| | - Steven C. Ricke
- Meat Science and Animal Biologics Discovery Program, Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, United States
| | - Steven L. Foley
- Division of Microbiology, FDA National Center for Toxicological Research, Jefferson, AR, United States
- Cellular and Molecular Biology Graduate Program, University of Arkansas, Fayetteville, AR, United States
| | - Jing Han
- Division of Microbiology, FDA National Center for Toxicological Research, Jefferson, AR, United States
- *Correspondence: Jing Han,
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Marmion M, Macori G, Ferone M, Whyte P, Scannell A. Survive and thrive: Control mechanisms that facilitate bacterial adaptation to survive manufacturing-related stress. Int J Food Microbiol 2022; 368:109612. [DOI: 10.1016/j.ijfoodmicro.2022.109612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/21/2022] [Accepted: 03/02/2022] [Indexed: 10/18/2022]
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Kanekar S, Devasya RP. Growth-phase specific regulation of cviI/R based quorum sensing associated virulence factors in Chromobacterium violaceum by linalool, a monoterpenoid. World J Microbiol Biotechnol 2022; 38:23. [PMID: 34989882 DOI: 10.1007/s11274-021-03208-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022]
Abstract
Quorum sensing (QS)-dependent gene regulation in bacteria performs a vital role in synchronization of cell-density-dependent functions. In Chromobacterium violaceum QS-dependent cviI/R regulatory genes are activated during the mid- or late-exponential phase of growth. However, sufficient evidence is lacking on the role of QS inhibitors on gene regulation at different phases of growth. Hence, we report the role of linalool, a natural monoterpenoid on QS mediated gene regulation at different stages of growth in C. violaceum by performing biosensor, growth kinetic and gene expression studies. In vitro and in vivo studies were performed for establishing role of linalool in reducing the virulence and infection by using HEK-293 T cell lines and Caenorhabditis elegans models respectively. C. violaceum CV026 with C6-HSL was used as control. The results showed linalool to be a QS inhibitor with an estimated IC50 of 63 µg/mL for violacein inhibition. At this concentration the cell density difference (delta OD600) of 0.14 from the compound was observed indicating the quorum concentration. The expression of cviI/R was initiated at mid-log phase (~ 18 h) and reached the maximum at 36 h in control whereas in treatment it remained significantly downregulated at all time points. The expression of violacein biosynthetic genes vioA, vioC, vioD and vioE was also downregulated by linalool. Infection studies with linalool showed higher survival rates in HEK-293T cell lines and C. elegans compared to the infection control. Taken together, this study proves linalool to be a QS inhibitor capable of attenuation of QS by controlling the cell density through cviI/R downregulation at the early phase of growth and hence offering scope for its application for controlling infections.
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Affiliation(s)
- Saptami Kanekar
- Microbiology and Biotechnology Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, Karnataka, 575018, India
| | - Rekha Punchappady Devasya
- Microbiology and Biotechnology Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, Karnataka, 575018, India.
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12
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Alves Coelho Trevisan D, Aline Zanetti Campanerut-Sa P, da Silva AF, Farias Pereira Batista A, Seixas FAV, Peralta RM, de Sa-Nakanishi AB, de Abreu Filho BA, Machinski Junior M, Graton Mikcha JM. Action of carvacrol in Salmonella Typhimurium biofilm: A proteomic study. J Appl Biomed 2021; 18:106-114. [PMID: 34907763 DOI: 10.32725/jab.2020.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 09/08/2020] [Indexed: 11/05/2022] Open
Abstract
Carvacrol presents action in Salmonella Typhimurium biofilms, however the antibiofilm mechanism of this compound has not been fully established yet. In the present study, the aim was to evaluate protein profile changes in S. Typhimurium biofilm treated with carvacrol. Proteomic analysis of treated versus untreated biofilm showed several changes in proteins involved with S. Typhimurium biofilm and antioxidant activity. The proteins DsbA (thiol: disulfide interchange protein DsbA), LuxS (S-ribosylhomocysteine lyase), DksA (RNA polymerase binding transcription factor DksA), and SODs (superoxide dismutases) A, B and C had their synthesis decreased after treatment with carvacrol. These proteins play a key role in S. Typhimurium biofilm formation, demonstrating the dynamic antibiofilm action of carvacrol. The differentially expressed proteins identified provide possible action targets for future studies in order to gain more insight into the mechanism of action of carvacrol on S. Typhimurium biofilm.
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Affiliation(s)
| | | | - Alex Fiori da Silva
- State University of Minas Gerais, Department of Biological Sciences, Ituiutaba, Brasil
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Rana K, Nayak SR, Bihary A, Sahoo AK, Mohanty KC, Palo SK, Sahoo D, Pati S, Dash P. Association of quorum sensing and biofilm formation with Salmonella virulence: story beyond gathering and cross-talk. Arch Microbiol 2021; 203:5887-5897. [PMID: 34586468 DOI: 10.1007/s00203-021-02594-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
Enteric fever (typhoid and paratyphoid fever) is a public health concern which contributes to mortality and morbidity all around the globe. It is caused mainly due to ingestion of contaminated food and water with a gram negative, rod-shaped, flagellated bacterium known as Salmonella enterica serotype typhi (typhoid fever) or paratyphi (paratyphoid fever). Clinical problems associated with Salmonellosis are mainly bacteraemia, gastroenteritis and enteric fever. The bacteria undergo various mechanisms to escape itself from immune reaction of the host, modulating immune response at the site of infection leading to virulence factor production and anti-microbial resistance. Biofilm is one of the adaptation mechanisms through which Salmonella survives in unfavourable conditions and thus is considered as a major threat to public health. Another property of the bacteria is "Quorum Sensing", which is a cell-cell communication and most of the pathogenic bacteria use it to coordinate the production of several virulence factors and other behaviours such as swarming and biofilm formation. Earlier, quorum sensing was believed to be just a medium for communication but, later on, its role in virulence has been studied. However, there are negligible information relating to interaction between quorum sensing and biofilm formation and how these events play crucial role in Salmonella pathogenesis. The review is a summary of updated information regarding how Salmonella uses these properties to spread more and survive better, making a challenge for clinicians and public health experts. Therefore, this review would help bring an insight regarding how biofilm formation and quorum sensing are inter-related and their role in pathogenesis and virulence of Salmonella.
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Affiliation(s)
- Khokan Rana
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India
| | | | - Alice Bihary
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India
| | - Ajay Ku Sahoo
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India
| | | | - Subrata Ku Palo
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India
| | - Debadutta Sahoo
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India
| | - Sanghamitra Pati
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India.
| | - Pujarini Dash
- ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, India.
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Sholpan A, Lamas A, Cepeda A, Franco CM. Salmonella spp. quorum sensing: an overview from environmental persistence to host cell invasion. AIMS Microbiol 2021; 7:238-256. [PMID: 34250377 PMCID: PMC8255907 DOI: 10.3934/microbiol.2021015] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/22/2021] [Indexed: 12/17/2022] Open
Abstract
Salmonella spp. is one of the main foodborne pathogens around the world. It has a cyclic lifestyle that combines host colonization with survival outside the host, implying that Salmonella has to adapt to different conditions rapidly in order to survive. One of these environments outside the host is the food production chain. In this environment, this foodborne pathogen has to adapt to different stress conditions such as acidic environments, nutrient limitation, desiccation, or biocides. One of the mechanisms used by Salmonella to survive under such conditions is biofilm formation. Quorum sensing plays an important role in the production of biofilms composed of cells from the same microorganism or from different species. It is also important in terms of food spoilage and regulates the pathogenicity and invasiveness of Salmonella by regulating Salmonella pathogenicity islands and flagella. Therefore, in this review, we will discuss the genetic mechanism involved in Salmonella quorum sensing, paying special attention to small RNAs and their post-regulatory activity in quorum sensing. We will further discuss the importance of this cell-to-cell communication mechanism in the persistence and spoilage of Salmonella in the food chain environment and the importance in the communication with microorganisms from different species. Subsequently, we will focus on the role of quorum sensing to regulate the virulence and invasion of host cells by Salmonella and on the interaction between Salmonella and other microbial species. This review offers an overview of the importance of quorum sensing in the Salmonella lifestyle.
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Affiliation(s)
- Amanova Sholpan
- Almaty Technological University, Almaty, Republic of Kazakhstan
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15
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Tazehabadi MH, Algburi A, Popov IV, Ermakov AM, Chistyakov VA, Prazdnova EV, Weeks R, Chikindas ML. Probiotic Bacilli Inhibit Salmonella Biofilm Formation Without Killing Planktonic Cells. Front Microbiol 2021; 12:615328. [PMID: 33679639 PMCID: PMC7925639 DOI: 10.3389/fmicb.2021.615328] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/26/2021] [Indexed: 12/24/2022] Open
Abstract
Salmonellosis is a foodborne infection caused by Salmonella. Domestic poultry species are one of the main reservoirs of Salmonella, which causes the foodborne infection salmonellosis, and are responsible for many cases of animal-to-human transmission. Keeping backyard chickens is now a growing trend, increasing the frequency of direct contact with the flock and, by consequence, the incidence of Salmonella infections. Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 are probiotic bacilli that produce the bacteriocins subtilosin A and subtilin, respectively. The antimicrobial activity of the two strains was determined against the reference strain Micrococcus luteus ATCC 10420. The cell-free supernatant of B. subtilis KATMIRA1933 inhibited biofilm formation by Salmonella enterica subsp. enterica serovar Hadar, Salmonella enterica subsp. enterica serovar Enteritidis phage type 4, and Salmonella enterica subsp. enterica serovar Thompson by 51.1, 48.3, and 56.9%, respectively. The cell-free supernatant of B. amyloliquefaciens B-1895 inhibited the biofilm formation of these Salmonella strains by 30.4, 28.6, and 35.5%, respectively. These findings suggest that the bacillus strains may have the potential to be used as probiotics and antibiotic alternatives for the control of Salmonella in poultry. The number of planktonic cells was unaffected by treatment with the cell-free supernatant. A co-culture of the Salmonella strains with either bacilli showed no signs of growth inhibition, suggesting that it might have been quorum sensing that is affected by the two Bacillus strains.
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Affiliation(s)
- Mahtab Hassanpour Tazehabadi
- Department of Biological Sciences, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, United States
| | - Ammar Algburi
- Department of Biotechnology, College of Science, University of Diyala, Baqubah, Iraq
- Department of Scholarship and Cultural Relation, Presidency of Diyala University, Baqubah, Iraq
| | - Igor V. Popov
- Research Laboratory «Agrobiotechnology Center», Don State Technical University, Rostov-on-Don, Russia
| | - Alexey M. Ermakov
- Research Laboratory «Agrobiotechnology Center», Don State Technical University, Rostov-on-Don, Russia
| | - Vladimir A. Chistyakov
- Research Laboratory «Agrobiotechnology Center», Don State Technical University, Rostov-on-Don, Russia
| | - Evgeniya V. Prazdnova
- Experimental Mutagenesis Laboratory, Southern Federal University, Rostov-on-Don, Russia
| | - Richard Weeks
- Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, United States
| | - Michael L. Chikindas
- Research Laboratory «Agrobiotechnology Center», Don State Technical University, Rostov-on-Don, Russia
- Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, United States
- I. M. Sechenov First Moscow State Medical University, Moscow, Russia
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16
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Hosseinzadeh S, Dastmalchi Saei H, Ahmadi M, Zahraei-Salehi T. Anti-quorum sensing effects of licochalcone A and epigallocatechin-3-gallate against Salmonella Typhimurium isolates from poultry sources. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2020; 11:273-279. [PMID: 33133465 PMCID: PMC7597796 DOI: 10.30466/vrf.2019.95102.2289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 02/02/2019] [Indexed: 01/10/2023]
Abstract
Quorum sensing (QS) is a cell density-dependent mechanism used by many pathogenic bacteria for regulating virulence gene expression. Inhibition or interruption of QS by medicinal plant remedies has been suggested as a new strategy for fighting against antibiotic-resistant bacteria. This study aimed to assess the impact of sub-inhibitory concentrations of licochalcone A (LAA) and epigallocatechin-3-gallate (EGCG) as natural plant products on the QS-associated genes (sdiA and luxS) expression. The PCR test was used to confirm the presence of sdiA and luxS genes in 23 S. Typhimurium isolates from poultry. The quantitative real-time PCR assay was used to analyze the expression of sdiA and luxS in S. Typhimurium isolates in response to the treatment with sub-inhibitory concentrations of LAA and EGCG at 45-min time point. All S. Typhimurium isolates showed the presence of sdiA and luxS genes (100%). As result, the expression of QS-related genes was significantly reduced in S. Typhimurium isolates following treatment with LAA and EGCG. In conclusion, LAA and EGCG showed anti-QS activity with down-regulation of both sdiA and luxS genes in S. Typhimurium, suggesting potential therapeutic use of them against salmonellosis. However, it must be pointed out that the safety and efficiency of these compounds need more thorough research.
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Affiliation(s)
- Somayyeh Hosseinzadeh
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - Habib Dastmalchi Saei
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - Malahat Ahmadi
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - Taghi Zahraei-Salehi
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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A Review of the Varied Uses of Macroalgae as Dietary Supplements in Selected Poultry with Special Reference to Laying Hen and Broiler Chickens. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2020. [DOI: 10.3390/jmse8070536] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Seaweeds comprise ca. 12,000 species. Global annual harvest is ca. 30.13 million metric tonnes, (valued ca. $11.7 billion USD in 2016) for various commercial applications. The growing scope of seaweed-based applications in food, agricultural fertilizers, animal feed additives, pharmaceuticals, cosmetics and personal care is expected to boost market demand. Agriculture and animal feed applications held the second largest seaweed market share in 2017, and the combined market is anticipated to reach much higher values by 2024 due to the impacts of current research and development targeting enhanced animal health and productivity. In general, seaweeds have been utilized in animal feed as a rich source of carbohydrates, protein, minerals, vitamins and dietary fibers with relatively well-balanced amino acid profiles and a unique blend of bioactive compounds. Worldwide, the animal nutrition market is largely driven by rising demand for poultry feeds, which represents ca. 47% of the total consumption for all animal nutrition. This review provides an overview of the utilization of specific seaweeds as sustainable feed sources for poultry production, including a detailed survey of seaweed-supplemented diets on growth, performance, gastrointestinal flora, disease, immunity and overall health of laying/broiler hens. Anti-microbial effects of seaweeds are also discussed.
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18
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Expression of Meiothermus ruber luxS in E. coli alters the antibiotic susceptibility and biofilm formation. Appl Microbiol Biotechnol 2020; 104:4457-4469. [PMID: 32215705 DOI: 10.1007/s00253-020-10480-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/28/2020] [Accepted: 02/18/2020] [Indexed: 12/12/2022]
Abstract
Quorum sensing (QS) and signal molecules used for interspecies communication are well defined in mesophiles, but there is still a plethora of microorganisms in which existence and mechanisms of QS need to be explored, thermophiles being among them. In silico analysis has revealed the presence of autoinducer-2 (AI-2) class of QS signaling molecules in thermophiles, synthesized by LuxS (AI-2 synthase), though the functions of this system are not known. In this study, LuxS of Meiothermus ruber was used for understanding the mechanism and functions of AI-2 based QS among thermophilic bacteria. The luxS gene of M. ruber was expressed in luxS- deletion mutant of Escherichia coli. Complementation of luxS resulted in significant AI-2 activity, enhanced biofilm formation, and antibiotic susceptibility. Transcriptome analysis showed significant differential expression of 204 genes between the luxS-complemented and luxS- deletion mutant of E. coli. Majority of the genes regulated by luxS belonged to efflux pumps. This elucidation may contribute towards finding novel alternatives against incessant antibiotic resistance in bacteria.Key Points• Expression of luxS in luxS-E. coli resulted in increase in biofilm index. • Reduction in the MIC of antibiotics was observed after complementation of luxS. • Downregulation of efflux pump genes was observed after complementation of luxS. • Transcriptome analysis showed that 204 genes were differentially regulated significantly.
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Chen L, Wilksch JJ, Liu H, Zhang X, Torres VVL, Bi W, Mandela E, Cao J, Li J, Lithgow T, Zhou T. Investigation of LuxS-mediated quorum sensing in Klebsiella pneumoniae. J Med Microbiol 2020; 69:402-413. [PMID: 32223838 PMCID: PMC7377169 DOI: 10.1099/jmm.0.001148] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Introduction Autoinducer-2 (AI-2) quorum sensing is a bacterial communication system that responds to cell density. The system requires luxS activity to produce AI-2, which can regulate gene expression and processes such as biofilm formation. Aim To investigate the role of luxS in biofilm formation and gene expression in the nosocomial pathogen Klebsiella pneumoniae. Methodology A ΔluxS gene deletion was made in K. pneumoniae KP563, an extensively drug-resistant isolate. AI-2 production was assessed in wild-type and ΔluxS strains grown in media supplemented with different carbohydrates. Potential roles of luxS in biofilm formation were investigated using a microtiter plate biofilm assay and scanning electron microscopy. Quantitative RT-PCR evaluated the expression of lipopolysaccharide (wzm and wbbM), polysaccharide (pgaA), and type 3 fimbriae (mrkA) synthesis genes in wild-type and ΔluxS mutant biofilm extracts. Results AI-2 production was dependent on the presence of luxS. AI-2 accumulation was highest during early stationary phase in media supplemented with glucose, sucrose or glycerol. Changes in biofilm architecture were observed in the ΔluxS mutant, with less surface coverage and reduced macrocolony formation; however, no differences in biofilm formation between the wild-type and ΔluxS mutant using a microtiter plate assay were observed. In ΔluxS mutant biofilm extracts, the expression of wzm was down-regulated, and the expression of pgaA, which encodes a porin for poly-β−1,6-N-acetyl-d-glucosamine (PNAG) polysaccharide secretion, was upregulated. Conclusion Relationships among AI-2-mediated quorum sensing, biofilm formation and gene expression of outer-membrane components were identified in K. pneumoniae. These inter-connected processes could be important for bacterial group behaviour and persistence.
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Affiliation(s)
- Lijiang Chen
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
| | - Jonathan J Wilksch
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Haiyang Liu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, PR China
| | - Xiaoxiao Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
| | - Von V L Torres
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Wenzi Bi
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
| | - Eric Mandela
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Jianming Cao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
| | - Jiahui Li
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, PR China
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20
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Sakarikou C, Kostoglou D, Simões M, Giaouris E. Exploitation of plant extracts and phytochemicals against resistant Salmonella spp. in biofilms. Food Res Int 2019; 128:108806. [PMID: 31955766 DOI: 10.1016/j.foodres.2019.108806] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 11/03/2019] [Accepted: 11/04/2019] [Indexed: 12/27/2022]
Abstract
Salmonella is one of the most frequent causes of foodborne outbreaks throughout the world. In the last years, the resistance of this and other pathogenic bacteria to antimicrobials has become a prime concern towards their successful control. In addition, the tolerance and virulence of pathogenic bacteria, such as Salmonella, are commonly related to their ability to form biofilms, which are sessile structures encountered on various surfaces and whose development is considered as a universal stress response mechanism. Indeed, the ability of Salmonella to form a biofilm seems to significantly contribute to its persistence in food production areas and clinical settings. Plant extracts and phytochemicals appear as promising sources of novel antimicrobials due to their cost-effectiveness, eco-friendliness, great structural diversity, and lower possibility of antimicrobial resistance development in comparison to synthetic chemicals. Research on these agents mainly attributes their antimicrobial activity to a diverse array of secondary metabolites. Bacterial cells are usually killed by the rupture of their cell envelope and in parallel the disruption of their energy metabolism when treated with such molecules, while their use at sub-inhibitory concentrations may also disrupt intracellular communication. The purpose of this article is to review the current available knowledge related to antimicrobial resistance of Salmonella in biofilms, together with the antibiofilm properties of plant extracts and phytochemicals against these detrimental bacteria towards their future application to control these in food production and clinical environments.
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Affiliation(s)
- Christina Sakarikou
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 and Makrygianni, GR-81 400 Myrina, Lemnos, Greece.
| | - Dimitra Kostoglou
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 and Makrygianni, GR-81 400 Myrina, Lemnos, Greece
| | - Manuel Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto,Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 and Makrygianni, GR-81 400 Myrina, Lemnos, Greece
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21
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Pradhan D, Negi VD. Repeated in-vitro and in-vivo exposure leads to genetic alteration, adaptations, and hypervirulence in Salmonella. Microb Pathog 2019; 136:103654. [DOI: 10.1016/j.micpath.2019.103654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/03/2019] [Accepted: 08/05/2019] [Indexed: 11/30/2022]
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22
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Krzyżek P. Challenges and Limitations of Anti-quorum Sensing Therapies. Front Microbiol 2019; 10:2473. [PMID: 31736912 PMCID: PMC6834643 DOI: 10.3389/fmicb.2019.02473] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/15/2019] [Indexed: 12/15/2022] Open
Abstract
Quorum sensing (QS) is a mechanism allowing microorganisms to sense population density and synchronously control genes expression. It has been shown that QS supervises the activity of many processes important for microbial pathogenicity, e.g., sporulation, biofilm formation, and secretion of enzymes or membrane vesicles. This contributed to the concept of anti-QS therapy [also called quorum quenching (QQ)] and the opportunity of its application in fighting against various types of pathogens. In recent years, many published articles reported promising results indicating the possibility of reducing pathogenicity of tested microorganisms and their easier eradication when co-treated with antibiotics. The aim of the present article is to point to the opposite, negative side of the QQ therapy, with particular emphasis on three fundamental properties attributed to anti-QS substances: the selectivity, virulence reduction, and lack of resistance against QQ. This point of view may highlight new directions of research, which should be taken into account in the future before the widespread introduction of QQ therapies in the treatment of people.
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Affiliation(s)
- Paweł Krzyżek
- Department of Microbiology, Wroclaw Medical University, Wrocław, Poland
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23
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Unraveling the role of quorum sensing-dependent metabolic homeostasis of the activated methyl cycle in a cooperative population of Burkholderia glumae. Sci Rep 2019; 9:11038. [PMID: 31363118 PMCID: PMC6667456 DOI: 10.1038/s41598-019-47460-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
The activated methyl cycle (AMC) is responsible for the generation of S-adenosylmethionine (SAM), which is a substrate of N-acylhomoserine lactone (AHL) synthases. However, it is unknown whether AHL-mediated quorum sensing (QS) plays a role in the metabolic flux of the AMC to ensure cell density-dependent biosynthesis of AHL in cooperative populations. Here we show that QS controls metabolic homeostasis of the AMC critical for AHL biosynthesis and cellular methylation in Burkholderia glumae, the causal agent of rice panicle blight. Activation of genes encoding SAM-dependent methyltransferases, S-adenosylhomocysteine (SAH) hydrolase, and methionine synthases involved in the AMC by QS is essential for maintaining the optimal concentrations of methionine, SAM, and SAH required for bacterial cooperativity as cell density increases. Thus, the absence of QS perturbed metabolic homeostasis of the AMC and caused pleiotropic phenotypes in B. glumae. A null mutation in the SAH hydrolase gene negatively affected AHL and ATP biosynthesis and the activity of SAM-dependent methyltransferases including ToxA, which is responsible for the biosynthesis of a key virulence factor toxoflavin in B. glumae. These results indicate that QS controls metabolic flux of the AMC to secure the biosynthesis of AHL and cellular methylation in a cooperative population.
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Ma Z, Zhang R, Hai D, Lu Z, Lv F, Zhao H, Zhang C, McAllister TA, Stanford K, Bie X. Antibiofilm activity and modes of action of a novel β-sheet peptide against multidrug-resistant Salmonella enterica. Food Res Int 2019; 125:108520. [PMID: 31554137 DOI: 10.1016/j.foodres.2019.108520] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/13/2019] [Accepted: 06/21/2019] [Indexed: 12/21/2022]
Abstract
S. enterica is an important foodborne pathogen worldwide. As some strains can form biofilms which may offer protection against antimicrobials, it is of interest to explore ways to prevent biofilm formation by S. enterica. In this study, we engineered a short β-sheet peptide WK2 (WKWKCTKSGCKWKW-NH2) and examined its antimicrobial and anti-biofilm activities against various S. enterica strains, including the multidrug-resistant S. Typhimurium DT104. WK2 displayed bacteriostatic activity with a geometric mean (GM) minimum inhibitory concentration (MIC) of 4.17 μg/mL, and bactericidal activity, with a GM lethal concentration (LC) of 7.51 μg/mL. Crystal violet staining and fluorescence measurements demonstrated that WK2 inhibited S. Typhimurium DT104 biofilm formation at 0.5 μg/mL and killed the sessile cells in biofilms at 8 μg/mL. Real-time polymerase chain reaction (qPCR) and microscopic observation revealed that the anti-biofilm activity of WK2 likely arises through the formation of complexes with bacterial DNA, inhibition of surface organelle biosynthesis and interference with autoinducer-2 (AI-2)-mediated quorum sensing (QS). Therefore, WK2 is a promising antimicrobial agent for the prevention and control of biofilms produced by multidrug-resistant S. enterica.
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Affiliation(s)
- Zhi Ma
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Rujing Zhang
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Dan Hai
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Zhaoxin Lu
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Fengxia Lv
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Haizhen Zhao
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Chong Zhang
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Tim A McAllister
- Agriculture and Agri-Food Canada, Lethbridge T1J 4B1, AB, Canada
| | - Kim Stanford
- Alberta Agriculture and Forestry, Lethbridge T1J 4V6, AB, Canada
| | - Xiaomei Bie
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
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25
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Liao H, Zhong X, Xu L, Ma Q, Wang Y, Cai Y, Guo X. Quorum-sensing systems trigger catalase expression to reverse the oxyR deletion-mediated VBNC state in Salmonella typhimurium. Res Microbiol 2019; 170:65-73. [DOI: 10.1016/j.resmic.2018.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 11/24/2022]
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26
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Lamas A, Regal P, Vázquez B, Miranda JM, Cepeda A, Franco CM. Salmonella and Campylobacter biofilm formation: a comparative assessment from farm to fork. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:4014-4032. [PMID: 29424050 DOI: 10.1002/jsfa.8945] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/16/2018] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
It takes several steps to bring food from the farm to the fork (dining table), and contamination with food-borne pathogens can occur at any point in the process. Campylobacter spp. and Salmonella spp. are the main microorganisms responsible for foodborne disease in the EU. These two pathogens are able to persist throughout the food supply chain thanks to their ability to form biofilms. Owing to the high prevalence of Salmonella and especially of Campylobacter in the food supply chain and the huge efforts of food authorities to reduce these levels, it is of great importance to fully understand their mechanisms of persistence. Diverse studies have evaluated the biofilm-forming capacity of foodborne pathogens isolated at different steps of food production. Nonetheless, the principal obstacle of these studies is to reproduce the real conditions that microorganisms encounter in the food supply chain. While there are a wide number of Salmonella biofilm studies, information on Campylobacter biofilms is still limited. A comparison between the two microorganisms could help to develop new research in the field of Campylobacter biofilms. Therefore, this review evaluates relevant work in the field of Salmonella and Campylobacter biofilms and the applicability of the data obtained from these studies to real working conditions. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Alexandre Lamas
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Patricia Regal
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Beatriz Vázquez
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - José M Miranda
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Alberto Cepeda
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Carlos M Franco
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
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27
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Meng L, Du Y, Liu P, Li X, Liu Y. Involvement of LuxS in Aeromonas salmonicida metabolism, virulence and infection in Atlantic salmon (Salmo salar L). FISH & SHELLFISH IMMUNOLOGY 2017; 64:260-269. [PMID: 28279794 DOI: 10.1016/j.fsi.2017.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/03/2017] [Accepted: 03/04/2017] [Indexed: 05/04/2023]
Abstract
Quorum sensing is a bacterial density dependent communication system, which regarded to regulate co-operative behaviors of community and mediated by extracellular signal molecules named autoinducers (AI). Among various signals, autoinducer-2 (AI-2) is believed to be the messengers inter species and produced by LuxS. For Aeromonas salmonicida (A. salmonicida), an opportunistic pathogen to many cold-water teleost, little information has been known about the function of AI-2 and LuxS. Therefore, our aim was to preliminarily clarify the function of LuxS in A. salmonicida. The consequences demonstrated that wild type A. salmonicida exhibited AI-2 activity and luxS defective mutant strain fail to produce AI-2 signals. Furthermore, it was suggested that luxS deficiency could impact bacterial morphology, surface properties and virulence dramatically. Challenge experiment showed a tendency that immune factors expressed earlier when Atlantic salmon was infected with ΔluxS strain. Overall, we hypothesis that AI-2 quorum sensing could regulate the expression of A-layer protein coding gene vapA, and then influence bacterial survival ability when suffered from attack of the host immune system. Though additional studies are warranted, our study will supply a new thinking to control the damage caused by A. salmonicida.
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Affiliation(s)
- Lingjie Meng
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China.
| | - Yishuai Du
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China
| | - Pengfei Liu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Xian Li
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China
| | - Ying Liu
- Dalian Ocean University, Dalian, 116023, PR China.
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de Almeida FA, Pimentel-Filho NDJ, Carrijo LC, Bento CBP, Baracat-Pereira MC, Pinto UM, de Oliveira LL, Vanetti MCD. Acyl homoserine lactone changes the abundance of proteins and the levels of organic acids associated with stationary phase in Salmonella Enteritidis. Microb Pathog 2017; 102:148-159. [DOI: 10.1016/j.micpath.2016.11.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/22/2016] [Accepted: 11/29/2016] [Indexed: 11/25/2022]
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Rajamanikandan S, Jeyakanthan J, Srinivasan P. Discovery of potent inhibitors targeting Vibrio harveyi LuxR through shape and e-pharmacophore based virtual screening and its biological evaluation. Microb Pathog 2016; 103:40-56. [PMID: 27939874 DOI: 10.1016/j.micpath.2016.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 11/29/2016] [Accepted: 12/05/2016] [Indexed: 01/12/2023]
Abstract
Quorum sensing is widely recognized as an efficient mechanism in the regulation and production of several virulence factors, biofilm formation and stress responses. For this reason, quorum sensing circuit is emerging as a novel drug target for the development of anti-infective. Recently, cinnamaldehyde derivatives have been found to interfere with master quorum sensing transcriptional regulator and thereby decreasing the DNA binding ability of LuxR. However, the exact mode of cinnamaldehyde binding with LuxR and receptor interaction still remains inconclusive. In the current study, combined method of molecular docking and molecular dynamics simulations were performed to investigate the binding mode, dynamic and energy aspects of cinnamaldehyde derivatives into the binding site of LuxR. Based on the experimental and computational evidences, LuxR-3,4-dichloro-cinnamaldehyde complex was chosen for the development of e-pharmacophore model. Further, shape and e-pharmacophore based virtual screening were performed against ChemBridge database to find potent and suitable ligands for LuxR. By comparing the results of shape and e-pharmacophore based virtual screening; best 9 hit molecules were selected for further studies including ADMET prediction, molecular dynamics simulations and Prime MM-GBSA calculations. From the 9 hit molecules, the top most compound 3-(2,4-dichlorophenyl)-1-(1H-pyrrol-2-yl)-2-propen-1-one (ChemBridge-7364106) was selected for in vitro assays using Vibrio harveyi. The result revealed that ChemBridge-7364106 significantly reduced the bioluminescence production in a dose dependent manner. In addition, ChemBridge-7364106 showed a significant inhibition in biofilm formation and motility in V. harveyi. The results from the study suggest that ChemBridge-7364106 could serve as an anti-quorum sensing molecule for V. harveyi.
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Affiliation(s)
- Sundaraj Rajamanikandan
- Department of Bioinformatics, Science campus Alagappa University, Karaikudi, Tamilnadu, India
| | - Jeyaraman Jeyakanthan
- Department of Bioinformatics, Science campus Alagappa University, Karaikudi, Tamilnadu, India
| | - Pappu Srinivasan
- Department of Animal Health and Management, Science campus Alagappa University, Karaikudi, Tamilnadu, India.
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Gart EV, Suchodolski JS, Welsh TH, Alaniz RC, Randel RD, Lawhon SD. Salmonella Typhimurium and Multidirectional Communication in the Gut. Front Microbiol 2016; 7:1827. [PMID: 27920756 PMCID: PMC5118420 DOI: 10.3389/fmicb.2016.01827] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 10/31/2016] [Indexed: 12/20/2022] Open
Abstract
The mammalian digestive tract is home to trillions of microbes, including bacteria, archaea, protozoa, fungi, and viruses. In monogastric mammals the stomach and small intestine harbor diverse bacterial populations but are typically less populated than the colon. The gut bacterial community (microbiota hereafter) varies widely among different host species and individuals within a species. It is influenced by season of the year, age of the host, stress and disease. Ideally, the host and microbiota benefit each other. The host provides nutrients to the microbiota and the microbiota assists the host with digestion and nutrient metabolism. The resident microbiota competes with pathogens for space and nutrients and, through this competition, protects the host in a phenomenon called colonization resistance. The microbiota participates in development of the host immune system, particularly regulation of autoimmunity and mucosal immune response. The microbiota also shapes gut–brain communication and host responses to stress; and, indeed, the microbiota is a newly recognized endocrine organ within mammalian hosts. Salmonella enterica serovar Typhimurium (S. Typhimurium hereafter) is a food-borne pathogen which adapts to and alters the gastrointestinal (GI) environment. In the GI tract, S. Typhimurium competes with the microbiota for nutrients and overcomes colonization resistance to establish infection. To do this, S. Typhimurium uses multiple defense mechanisms to resist environmental stressors, like the acidic pH of the stomach, and virulence mechanisms which allow it to invade the intestinal epithelium and disseminate throughout the host. To coordinate gene expression and disrupt signaling within the microbiota and between host and microbiota, S. Typhimurium employs its own chemical signaling and may regulate host hormone metabolism. This review will discuss the multidirectional interaction between S. Typhimurium, host and microbiota as well as mechanisms that allow S. Typhimurium to succeed in the gut.
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Affiliation(s)
- Elena V Gart
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station TX, USA
| | - Jan S Suchodolski
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station TX, USA
| | - Thomas H Welsh
- Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, College Station TX, USA
| | - Robert C Alaniz
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M Health Science Center, Texas A&M University, College Station TX, USA
| | | | - Sara D Lawhon
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station TX, USA
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Walawalkar YD, Vaidya Y, Nayak V. Response ofSalmonellaTyphi to bile-generated oxidative stress: implication of quorum sensing and persister cell populations. Pathog Dis 2016; 74:ftw090. [DOI: 10.1093/femspd/ftw090] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2016] [Indexed: 12/20/2022] Open
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Molecular Docking, Molecular Dynamics Simulations, Computational Screening to Design Quorum Sensing Inhibitors Targeting LuxP of Vibrio harveyi and Its Biological Evaluation. Appl Biochem Biotechnol 2016; 181:192-218. [DOI: 10.1007/s12010-016-2207-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 08/05/2016] [Indexed: 10/21/2022]
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Rajamanikandan S, Jeyakanthan J, Srinivasan P. Binding mode exploration of LuxR-thiazolidinedione analogues, e-pharmacophore-based virtual screening in the designing of LuxR inhibitors and its biological evaluation. J Biomol Struct Dyn 2016; 35:897-916. [PMID: 27141809 DOI: 10.1080/07391102.2016.1166455] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Master quorum sensing (QS) regulator LuxR of Vibrio harveyi is a unique member of the TetR protein superfamily. Recent studies have demonstrated the contribution of thiazolidinedione analogues in blocking QS by decreasing the DNA-binding ability of LuxR. However, the precise mechanism of thiazolidinedione analogues binding to LuxR is still unclear. In the present study, molecular docking combined with molecular dynamics (MD) simulations was performed to understand the mechanism of ligand binding to the protein. The binding pattern of thiazolidinedione analogues showed strong hydrogen bonding interactions with the amine group (NH) of polar amino acid residue Asn133 and carbonyl (C=O) interaction with negatively charged amino acid residue Gln137 in the binding site of LuxR. The stability of the protein-ligand complexes was confirmed by running 50 ns of MD simulations. Further, the four-featured pharmacophore hypothesis (AHHD) consists of one acceptor (A), two hydrophobic regions (HH) and one donor (D) group was used to screen compounds from ChemBridge database. The identified hit molecules were shown to have excellent pharmacokinetic properties under the acceptable range. Based on the computational studies, ChemBridge_5343641 was selected for in vitro assays. The 1-(4-chlorophenoxy)-3-[(4,6-dimethyl-2-pyrimidinyl)thio]-2-propanol (ChemBridge_5343641) showed significant reduction in bioluminescence in a dose-dependent manner. In addition, ChemBridge_5343641 inhibits biofilm formation and motility in V. harveyi. The result from the study suggests that ChemBridge_5343641 could serve as an anti-QS molecule.
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Affiliation(s)
| | - Jeyaraman Jeyakanthan
- a Department of Bioinformatics , Alagappa University , Karaikudi , TamilNadu , India
| | - Pappu Srinivasan
- a Department of Bioinformatics , Alagappa University , Karaikudi , TamilNadu , India.,b Department of Animal Health and Management , Alagappa University , Karaikudi , TamilNadu , India
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Kulshreshtha G, Borza T, Rathgeber B, Stratton GS, Thomas NA, Critchley A, Hafting J, Prithiviraj B. Red Seaweeds Sarcodiotheca gaudichaudii and Chondrus crispus down Regulate Virulence Factors of Salmonella Enteritidis and Induce Immune Responses in Caenorhabditis elegans. Front Microbiol 2016; 7:421. [PMID: 27065981 PMCID: PMC4814495 DOI: 10.3389/fmicb.2016.00421] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/16/2016] [Indexed: 11/23/2022] Open
Abstract
Red seaweeds are a rich source of unique bioactive compounds and secondary metabolites that are known to improve human and animal health. S. Enteritidis is a broad range host pathogen, which contaminates chicken and poultry products that end into the human food chain. Worldwide, Salmonella outbreaks have become an important economic and public health concern. Moreover, the development of resistance in Salmonella serovars toward multiple drugs highlights the need for alternative control strategies. This study evaluated the antimicrobial property of red seaweeds extracts against Salmonella Enteritidis using the Caenorhabditis elegans infection model. Six red seaweed species were tested for their antimicrobial activity against S. Enteritidis and two, Sarcodiotheca gaudichaudii (SG) and Chondrus crispus (CC), were found to exhibit such properties. Spread plate assay revealed that SG and CC (1%, w/v) significantly reduced the growth of S. Enteritidis. Seaweed water extracts (SWE) of SG and CC, at concentrations from 0.4 to 2 mg/ml, significantly reduced the growth of S. Enteritidis (log CFU 4.5–5.3 and log 5.7–6.0, respectively). However, methanolic extracts of CC and SG did not affect the growth of S. Enteritidis. Addition of SWE (0.2 mg/ml, CC and SG) significantly decreased biofilm formation and reduced the motility of S. Enteritidis. Quantitative real-time PCR analyses showed that SWE (CC and SG) suppressed the expression of quorum sensing gene sdiA and of Salmonella Pathogenesis Island-1 (SPI-1) associated genes sipA and invF, indicating that SWE might reduce the invasion of S. Enteritidis in the host by attenuating virulence factors. Furthermore, CC and SG water extracts significantly improved the survival of infected C. elegans by impairing the ability of S. Enteritidis to colonize the digestive tract of the nematode and by enhancing the expression of C. elegans immune responsive genes. As the innate immune response pathways of C. elegans and mammals show a high degree of conservation, these results suggest that these SWE may also impart beneficial effects on animal and human health.
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Affiliation(s)
- Garima Kulshreshtha
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie UniversityTruro, NS, Canada; Acadian Seaplants LimitedDartmouth, NS, Canada
| | - Tudor Borza
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Bruce Rathgeber
- Department of Plant and Animal Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Glenn S Stratton
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University Halifax, NS, Canada
| | | | | | - Balakrishnan Prithiviraj
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
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FabR regulates Salmonella biofilm formation via its direct target FabB. BMC Genomics 2016; 17:253. [PMID: 27004424 PMCID: PMC4804515 DOI: 10.1186/s12864-016-2387-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 01/08/2016] [Indexed: 12/02/2022] Open
Abstract
Background Biofilm formation is an important survival strategy of Salmonella in all environments. By mutant screening, we showed a knock-out mutant of fabR, encoding a repressor of unsaturated fatty acid biosynthesis (UFA), to have impaired biofilm formation. In order to unravel how this regulator impinges on Salmonella biofilm formation, we aimed at elucidating the S. Typhimurium FabR regulon. Hereto, we applied a combinatorial high-throughput approach, combining ChIP-chip with transcriptomics. Results All the previously identified E. coli FabR transcriptional target genes (fabA, fabB and yqfA) were shown to be direct S. Typhimurium FabR targets as well. As we found a fabB overexpressing strain to partly mimic the biofilm defect of the fabR mutant, the effect of FabR on biofilms can be attributed at least partly to FabB, which plays a key role in UFA biosynthesis. Additionally, ChIP-chip identified a number of novel direct FabR targets (the intergenic regions between hpaR/hpaG and ddg/ydfZ) and yet putative direct targets (i.a. genes involved in tRNA metabolism, ribosome synthesis and translation). Next to UFA biosynthesis, a number of these direct targets and other indirect targets identified by transcriptomics (e.g. ribosomal genes, ompA, ompC, ompX, osmB, osmC, sseI), could possibly contribute to the effect of FabR on biofilm formation. Conclusion Overall, our results point at the importance of FabR and UFA biosynthesis in Salmonella biofilm formation and their role as potential targets for biofilm inhibitory strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2387-x) contains supplementary material, which is available to authorized users.
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Wang H, Dong Y, Wang G, Xu X, Zhou G. Effect of growth media on gene expression levels in Salmonella Typhimurium biofilm formed on stainless steel surface. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.06.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Assessment of the effect of a Salmonella enterica ser. Typhimurium culture supernatant on the single-cell lag time of foodborne pathogens. Int J Food Microbiol 2015; 215:143-8. [PMID: 26433459 DOI: 10.1016/j.ijfoodmicro.2015.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 09/05/2015] [Accepted: 09/11/2015] [Indexed: 12/11/2022]
Abstract
The objective of this study was the in vitro evaluation of the effect of a cell-free microbial supernatant, produced by a luxS-positive Salmonella enterica ser. Typhimurium strain, on the single-cell growth kinetic behavior of two strains of S. enterica (serotypes Enteritidis and Typhimurium) and a methicillin-resistant Staphylococcus aureus strain. The single-cell lag time (λ) of the pathogens was estimated in the absence and presence (20% v/v) of microbial supernatant based on optical density measurements. As demonstrated by the obtained results, the tested microbial supernatant had a strain-specific effect on the single-cell λ and its variability. Although the mean λ values were similar in the absence and presence of microbial supernatant in the case of Salmonella Enteritidis, a significant (P ≤ 0.05) reduction and increase in the mean value of this parameter in the presence of microbial supernatant were observed for Salmonella Typhimurium and St. aureus, respectively. With regard to the effect of the tested microbial supernatant on the single-cell variability of λ, similar λ distributions were obtained in its absence and presence for S. Enteritidis, while considerable differences were noted for the other two tested organisms; the coefficient of variation of λ in the absence and presence of microbial supernatant was 41.6 and 69.8% for S. Typhimurium, respectively, with the corresponding values for St. aureus being 74.0 and 56.9%. As demonstrated by the results of bioassays, the tested microbial supernatant exhibited autoinducer-2 activity, indicating a potential association of such quorum sensing compounds with the observed effects. Although preliminary in nature, the collected data provide a good basis for future research on the role of quorum sensing in the single-cell growth behavior of foodborne pathogens.
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Giaouris E, Heir E, Desvaux M, Hébraud M, Møretrø T, Langsrud S, Doulgeraki A, Nychas GJ, Kačániová M, Czaczyk K, Ölmez H, Simões M. Intra- and inter-species interactions within biofilms of important foodborne bacterial pathogens. Front Microbiol 2015; 6:841. [PMID: 26347727 PMCID: PMC4542319 DOI: 10.3389/fmicb.2015.00841] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 07/31/2015] [Indexed: 12/15/2022] Open
Abstract
A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety.
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Affiliation(s)
- Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, Myrina, Lemnos Island, Greece
| | - Even Heir
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, Centre Auvergne-Rhône-Alpes, Saint-Genès-Champanelle, France
| | - Michel Hébraud
- INRA, UR454 Microbiologie, Centre Auvergne-Rhône-Alpes, Saint-Genès-Champanelle, France
| | - Trond Møretrø
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Solveig Langsrud
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Agapi Doulgeraki
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Faculty of Foods, Biotechnology and Development, Agricultural University of Athens, Athens, Greece
| | - George-John Nychas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Faculty of Foods, Biotechnology and Development, Agricultural University of Athens, Athens, Greece
| | - Miroslava Kačániová
- Department of Microbiology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Nitra, Slovakia
| | - Katarzyna Czaczyk
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Poznań, Poland
| | - Hülya Ölmez
- TÜBİTAK Marmara Research Center, Food Institute, Gebze, Kocaeli, Turkey
| | - Manuel Simões
- Laboratory for Process Engineering, Environment, Biotechnology and Energy, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Transcriptional response of selected genes of Salmonella enterica serovar Typhimurium biofilm cells during inactivation by superheated steam. Int J Food Microbiol 2015; 192:117-23. [DOI: 10.1016/j.ijfoodmicro.2014.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 10/03/2014] [Accepted: 10/05/2014] [Indexed: 01/30/2023]
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Willias SP, Chauhan S, Motin VL. Functional characterization of Yersinia pestis aerobic glycerol metabolism. Microb Pathog 2014; 76:33-43. [PMID: 25220241 DOI: 10.1016/j.micpath.2014.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
Yersinia pestis biovar Orientalis isolates have lost the capacity to ferment glycerol. Herein we provide experimental validation that a 93 bp in-frame deletion within the glpD gene encoding the glycerol-3-phosphate dehydrogenase present in all biovar Orientalis strains is sufficient to disrupt aerobic glycerol fermentation. Furthermore, the inability to ferment glycerol is often insured by a variety of additional mutations within the glpFKX operon which prevents glycerol internalization and conversion to glycerol-3-phosphate. The physiological impact of functional glpFKX in the presence of dysfunctional glpD was assessed. Results demonstrate no change in growth kinetics at 26 °C and 37 °C. Mutants deficient in glpD displayed decreased intracellular accumulation of glycerol-3-phosphate, a characterized inhibitor of cAMP receptor protein (CRP) activation. Since CRP is rigorously involved in global regulation Y. pestis virulence, we tested a possible influence of a single glpD mutation on virulence. Nonetheless, subcutaneous and intranasal murine challenge was not impacted by glycerol metabolism. As quantified by crystal violet assay, biofilm formation of the glpD-deficient KIM6+ mutant was mildly repressed; whereas, chromosomal restoration of glpD in CO92 resulted in a significant increase in biofilm formation.
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Affiliation(s)
- Stephan P Willias
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Sadhana Chauhan
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Vladimir L Motin
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA.
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Habimana O, Nesse L, Møretrø T, Berg K, Heir E, Vestby L, Langsrud S. The persistence of Salmonella
following desiccation under feed processing environmental conditions: a subject of relevance. Lett Appl Microbiol 2014; 59:464-70. [DOI: 10.1111/lam.12308] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Affiliation(s)
- O. Habimana
- Nofima AS; Norwegian Institute of Food, Fishery and Aquaculture; Ås Norway
| | - L.L. Nesse
- Norwegian Veterinary Institute; Oslo Norway
| | - T. Møretrø
- Nofima AS; Norwegian Institute of Food, Fishery and Aquaculture; Ås Norway
| | - K. Berg
- Norwegian Veterinary Institute; Oslo Norway
| | - E. Heir
- Nofima AS; Norwegian Institute of Food, Fishery and Aquaculture; Ås Norway
| | | | - S. Langsrud
- Nofima AS; Norwegian Institute of Food, Fishery and Aquaculture; Ås Norway
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The Dynamic Interactions between Salmonella and the Microbiota, within the Challenging Niche of the Gastrointestinal Tract. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:846049. [PMID: 27437481 PMCID: PMC4897363 DOI: 10.1155/2014/846049] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/14/2014] [Indexed: 12/25/2022]
Abstract
Understanding how Salmonella species establish successful infections remains a foremost research priority. This gastrointestinal pathogen not only faces the hostile defenses of the host's immune system, but also faces fierce competition from the large and diverse community of microbiota for space and nutrients. Salmonella have solved these challenges ingeniously. To jump-start growth, Salmonella steal hydrogen produced by the gastrointestinal microbiota. Type 3 effector proteins are subsequently secreted by Salmonella to trigger potent inflammatory responses, which generate the alternative terminal electron acceptors tetrathionate and nitrate. Salmonella exclusively utilize these electron acceptors for anaerobic respiration, permitting metabolic access to abundant substrates such as ethanolamine to power growth blooms. Chemotaxis and flagella-mediated motility enable the identification of nutritionally beneficial niches. The resulting growth blooms also promote horizontal gene transfer amongst the resident microbes. Within the gastrointestinal tract there are opportunities for chemical signaling between host cells, the microbiota, and Salmonella. Host produced catecholamines and bacterial autoinducers form components of this chemical dialogue leading to dynamic interactions. Thus, Salmonella have developed remarkable strategies to initially shield against host defenses and to transiently compete against the intestinal microbiota leading to successful infections. However, the immunocompetent host is subsequently able to reestablish control and clear the infection.
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Biofilm formation of meat-borne Salmonella enterica and inhibition by the cell-free supernatant from Pseudomonas aeruginosa. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.01.047] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Vikram A, Jayaprakasha GK, Uckoo RM, Patil BS. Inhibition of Escherichia coli O157:H7 motility and biofilm by β-sitosterol glucoside. Biochim Biophys Acta Gen Subj 2013; 1830:5219-28. [PMID: 23891936 DOI: 10.1016/j.bbagen.2013.07.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 07/01/2013] [Accepted: 07/19/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND Escherichia coli O157:H7 (EHEC) is a food borne pathogen, which causes diarrhea and hemolytic uremic syndrome (HUS). There is an urgent need of novel antimicrobials for treatment of EHEC as conventional antibiotics enhance shiga toxin production and potentiate morbidity and mortality. METHODS Six bioactive compounds were isolated, identified from citrus and evaluated for the effect on EHEC biofilm and motility. To determine the possible mode of action, a series of genes known to affect biofilm and motility were overexpressed and the effect on biofilm/motility was assessed. Furthermore, the relative expression of genes involved in motility and biofilm formation was measured by qRT-PCR in presence and absence of phytochemicals, to examine the repression caused by test compounds. RESULTS The β-sitosterol glucoside (SG) was identified as the most potent inhibitor of EHEC biofilm formation and motility without affecting the cell viability. Furthermore, SG appears to inhibit the biofilm and motility through rssAB and hns mediated repression of flagellar master operon flhDC. CONCLUSION SG may serve as novel lead compound for further development of anti-virulence drugs. GENERAL SIGNIFICANCE Plant sterols constitute significant part of diet and impart various health benefits. Here we present the first evidence that SG, a plant sterol has significant effect on EHEC motility, a critical virulence factor, and may have potential application as antivirulence strategy.
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Affiliation(s)
- Amit Vikram
- Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
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Haigh R, Kumar B, Sandrini S, Freestone P. Mutation design and strain background influence the phenotype ofEscherichia coli luxSmutants. Mol Microbiol 2013; 88:951-69. [DOI: 10.1111/mmi.12237] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Richard Haigh
- Department of Genetics; University of Leicester; Leicester UK
| | - Brijesh Kumar
- Department of Infection, Immunity and Inflammation; University of Leicester; Leicester UK
| | - Sara Sandrini
- Department of Infection, Immunity and Inflammation; University of Leicester; Leicester UK
| | - Primrose Freestone
- Department of Infection, Immunity and Inflammation; University of Leicester; Leicester UK
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Cox CE, McClelland M, Teplitski M. Consequences of disrupting Salmonella AI-2 signaling on interactions within soft rots. PHYTOPATHOLOGY 2013; 103:352-361. [PMID: 23324045 DOI: 10.1094/phyto-09-12-0237-fi] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Within soft rots, Salmonella spp. reach population densities 10- to 100-fold higher than within intact plants. The hypothesis that Salmonella spp. exchange AI-2 signals with Pectobacterium carotovorum to increase its competitive fitness was tested using mutants involved in AI-2 production (luxS) or perception (lsrACDBF or lsrG). Co-infections of a wild-type Salmonella sp. and its AI-2 mutants (at ≈3 to 10(4)) were established in green or red tomato ('FL 47' or 'Campari' for 3 or 5 days) as well as tomato co-infected with Pectobacterium (at 10(9)) or its luxS mutant. There were no significant differences in the competitive fitness of Salmonella, indicating that AI-2 signaling is not a major input in the interactions between these organisms under the tested conditions. A Salmonella lsrG::tnpR-lacZ resolvase in vivo expression technology (RIVET) reporter, constructed to monitor AI-2-related gene expression, responded strongly to the luxS deletion but only weakly to external sources of AI-2. Growth in soft rots generally decreased RIVET resolution; however, the effect was not correlated to the luxS genotype of the Pectobacterium sp. The results of this study show that AI-2 signaling offers no significant benefit to Salmonella spp. in this model of colonization of tomato or soft rots.
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Affiliation(s)
- Clayton E Cox
- Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
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Karavolos MH, Winzer K, Williams P, Khan CMA. Pathogen espionage: multiple bacterial adrenergic sensors eavesdrop on host communication systems. Mol Microbiol 2012; 87:455-65. [PMID: 23231070 DOI: 10.1111/mmi.12110] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2012] [Indexed: 12/11/2022]
Abstract
The interactions between bacterial pathogens and their eukaryotic hosts are vital in determining the outcome of infections. Bacterial pathogens employ molecular sensors to detect and facilitate adaptation to changes in their niche. The sensing of these extracellular signals enables the pathogen to navigate within mammalian hosts. Intercellular bacterial communication is facilitated by the production and sensing of autoinducer (AI) molecules via quorum sensing. More recently, AI-3 and the host neuroendocrine (NE) hormones adrenaline and noradrenaline were reported to display cross-talk for the activation of the same signalling pathways. Remarkably, there is increasing evidence to suggest that enteric bacteria sense and respond to the host NE stress hormones adrenaline and noradrenaline to modulate virulence. These responses can be inhibited by α and β-adrenergic receptor antagonists implying a bacterial receptor-based sensing and signalling cascade. In Escherichia coli O157:H7 and Salmonella, QseC has been proposed as the adrenergic receptor. Strikingly, there is an increasing body of evidence that not all the bacterial adrenergic responses require signalling through QseC. Here we provide additional hypotheses to reconcile these observations implicating the existence of alternative adrenergic receptors including BasS, QseE and CpxA and their associated signalling cascades with major roles in interkingdom communication.
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Affiliation(s)
- Michail H Karavolos
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle NE2 4HH, UK
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Sooresh A, Zeng Z, Chandrasekharan J, Pillai SD, Sayes CM. A physiologically relevant approach to characterize the microbial response to colloidal particles in food matrices within a simulated gastrointestinal tract. Food Chem Toxicol 2012; 50:2971-7. [DOI: 10.1016/j.fct.2012.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 05/08/2012] [Accepted: 05/11/2012] [Indexed: 11/16/2022]
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Pereira CS, Thompson JA, Xavier KB. AI-2-mediated signalling in bacteria. FEMS Microbiol Rev 2012; 37:156-81. [PMID: 22712853 DOI: 10.1111/j.1574-6976.2012.00345.x] [Citation(s) in RCA: 361] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/06/2012] [Accepted: 06/08/2012] [Indexed: 02/06/2023] Open
Abstract
Success in nature depends upon an ability to perceive and adapt to the surrounding environment. Bacteria are not an exception; they recognize and constantly adjust to changing situations by sensing environmental and self-produced signals, altering gene expression accordingly. Autoinducer-2 (AI-2) is a signal molecule produced by LuxS, an enzyme found in many bacterial species and thus proposed to enable interspecies communication. Two classes of AI-2 receptors and many layers and interactions involved in downstream signalling have been identified so far. Although AI-2 has been implicated in the regulation of numerous niche-specific behaviours across the bacterial kingdom, interpretation of these results is complicated by the dual role of LuxS in signalling and the activated methyl cycle, a crucial central metabolic pathway. In this article, we present a comprehensive review of the discovery and early characterization of AI-2, current developments in signal detection, transduction and regulation, and the major studies investigating the phenotypes regulated by this molecule. The development of novel tools should help to resolve many of the remaining questions in the field; we highlight how these advances might be exploited in AI-2 quorum quenching, treatment of diseases, and the manipulation of beneficial behaviours caused by polyspecies communities.
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