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Cieza MYR, Bonsaglia ECR, Rall VLM, dos Santos MV, Silva NCC. Staphylococcal Enterotoxins: Description and Importance in Food. Pathogens 2024; 13:676. [PMID: 39204276 PMCID: PMC11357529 DOI: 10.3390/pathogens13080676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 09/03/2024] Open
Abstract
Staphylococcus aureus stands out as one of the most virulent pathogens in the genus Staphylococcus. This characteristic is due to its ability to produce a wide variety of staphylococcal enterotoxins (SEs) and exotoxins, which in turn can cause staphylococcal food poisoning (SFP), clinical syndromes such as skin infections, inflammation, pneumonia, and sepsis, in addition to being associated with the development of inflammation in the mammary glands of dairy cattle, which results in chronic mastitis and cell necrosis. SEs are small globular proteins that combine superantigenic and emetic activities; they are resistant to heat, low temperatures, and proteolytic enzymes and are tolerant to a wide pH range. More than 24 SE genes have been well described (SEA-SEE, SEG, SEH, SEI, SEJ, SElK, SElL, SElM, SElN, SElO, SElP, SElQ, SElR, SElS, SElT, SElU, SElV, SElW, SElX, SElY, and SElZ), being a part of different SFP outbreaks, clinical cases, and isolated animal strains. In recent years, new genes (sel26, sel27, sel28, sel31, sel32, and sel33) from SEs have been described, as well as two variants (seh-2p and ses-3p) resulting in a total of thirty-three genes from Ses, including the nine variants that are still in the process of genetic and molecular structure evaluation. SEs are encoded by genes that are located in mobile genetic elements, such as plasmids, prophages, pathogenicity islands, and the enterotoxin gene cluster (egc), and housed in the genomic island of S. aureus. Both classical SEs and SE-like toxins (SEls) share phylogenetic relationships, structure, function, and sequence homology, which are characteristics for the production of new SEs through recombination processes. Due to the epidemiological importance of SEs, their rapid assessment and detection have been crucial for food security and public health; for this reason, different methods of identification of SEs have been developed, such as liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), molecular methods, and whole-genome sequencing; providing the diagnosis of SEs and a better understanding of the occurrence, spread, and eradication of SEs. This review provides scientific information on the enterotoxins produced by S. aureus, such as structural characteristics, genetic organization, regulatory mechanisms, superantigen activity, mechanisms of action used by SEs at the time of interaction with the immune system, methods of detection of SEs, and recent biocontrol techniques used in food.
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Affiliation(s)
- Mirian Yuliza Rubio Cieza
- Department of Food Science and Nutrition, School of Food Engineering, University of Campinas (UNICAMP), Campinas 13083-862, Brazil;
| | - Erika Carolina Romão Bonsaglia
- Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, Brazil; (E.C.R.B.); (M.V.d.S.)
| | - Vera Lucia Mores Rall
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University, Botucatu 18618-691, Brazil;
| | - Marcos Veiga dos Santos
- Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, Brazil; (E.C.R.B.); (M.V.d.S.)
| | - Nathália Cristina Cirone Silva
- Department of Food Science and Nutrition, School of Food Engineering, University of Campinas (UNICAMP), Campinas 13083-862, Brazil;
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Santiago-Maldonado X, Rodríguez-Martínez JA, López L, Cunci L, Bayro M, Nicolau E. Selection, characterization, and biosensing applications of DNA aptamers targeting cyanotoxin BMAA. RSC Adv 2024; 14:13787-13800. [PMID: 38681844 PMCID: PMC11046380 DOI: 10.1039/d4ra02384f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024] Open
Abstract
Scientists have established a connection between environmental exposure to toxins like β-N-methylamino-l-alanine (BMAA) and a heightened risk of neurodegenerative disorders. BMAA is a byproduct from certain strains of cyanobacteria that are present in ecosystems worldwide and is renowned for its bioaccumulation and biomagnification in seafood. The sensitivity, selectivity, and reproducibility of the current analytical techniques are insufficient to support efforts regarding food safety and environment monitoring adequately. This work outlines the in vitro selection of BMAA-specific DNA aptamers via the systematic evolution of ligands through exponential enrichment (SELEX). Screening and characterization of the full-length aptamers was achieved using the SYBR Green (SG) fluorescence displacement assay. Aptamers BMAA_159 and BMAA_165 showed the highest binding affinities, with dissociation constants (Kd) of 2.2 ± 0.1 μM and 0.32 ± 0.02 μM, respectively. After truncation, the binding affinity was confirmed using a BMAA-conjugated fluorescence assay. The Kd values for BMAA_159_min and BMAA_165_min were 6 ± 1 μM and 0.63 ± 0.02 μM, respectively. Alterations in the amino proton region studied using solution nuclear magnetic resonance (NMR) provided further evidence of aptamer-target binding. Additionally, circular dichroism (CD) spectroscopy revealed that BMAA_165_min forms hybrid G-quadruplex (G4) structures. Finally, BMAA_165_min was used in the development of an electrochemical aptamer-based (EAB) sensor that accomplished sensitive and selective detection of BMAA with a limit of detection (LOD) of 1.13 ± 0.02 pM.
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Affiliation(s)
- Xaimara Santiago-Maldonado
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | | | - Luis López
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | - Lisandro Cunci
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
| | - Marvin Bayro
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
- Molecular Science Research Center, University of Puerto Rico San Juan 00931-3346 USA
| | - Eduardo Nicolau
- Department of Chemistry, University of Puerto Rico San Juan PR 00925-2437 USA +1-787-522-2150 +1-787-292-9820
- Molecular Science Research Center, University of Puerto Rico San Juan 00931-3346 USA
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3
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Chen J, Zhou J, Peng Y, Xie Y, Xiao Y. Aptamers: A prospective tool for infectious diseases diagnosis. J Clin Lab Anal 2022; 36:e24725. [PMID: 36245423 PMCID: PMC9701868 DOI: 10.1002/jcla.24725] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 12/05/2022] Open
Abstract
It is well known that people's health is seriously threatened by various pathogens (such as Mycobacterium tuberculosis, Treponema pallidum, Novel coronavirus, HIV, Mucor, etc.), which leads to heavy socioeconomic burdens. Therefore, early and accurate pathogen diagnosis is essential for timely and effective therapies. Up to now, diagnosing human contagious diseases at molecule and nano levels is remarkably difficult owing to insufficient valid probes when it comes to determining the biological markers of pathogens. Aptamers are a set of high‐specificity and high‐sensitivity plastic oligonucleotides screened in vitro via the selective expansion of ligands by exponential enrichment (SELEX). With the advent of aptamer‐based technologies, their merits have aroused mounting academic interest. In recent years, as new detection and treatment tools, nucleic acid aptamers have been extensively utilized in the field of biomedicine, such as pathogen detection, new drug development, clinical diagnosis, nanotechnology, etc. However, the traditional SELEX method is cumbersome and has a long screening cycle, and it takes several months to screen out aptamers with high specificity. With the persistent development of SELEX‐based aptamer screening technologies, the application scenarios of aptamers have become more and more extensive. The present research briefly reviews the research progress of nucleic acid aptamers in the field of biomedicine, especially in the diagnosis of contagious diseases.
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Affiliation(s)
- Jiayi Chen
- Department of Clinical Laboratory, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jiahuan Zhou
- Department of Clinical Laboratory, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Yunchi Peng
- Department of Clinical Laboratory, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Yafeng Xie
- Department of Clinical Laboratory, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Yongjian Xiao
- Department of Clinical Laboratory, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
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Singhal C, Bruno JG, Kaushal A, Sharma TK. Recent Advances and a Roadmap to Aptamer-Based Sensors for Bloodstream Infections. ACS APPLIED BIO MATERIALS 2021; 4:3962-3984. [PMID: 35006817 DOI: 10.1021/acsabm.0c01358] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The present review is intended to describe bloodstream infections (BSIs), the major pathogens responsible for BSIs, conventional tests and their limitations, commercially available methods used, and the aptamer and nanomaterials-based approaches developed so far for the detection of BSIs. The advantages associated with aptamers and the aptamer-based sensors, the comparison between the aptamers and the antibodies, and the various types of aptasensors developed so far for the detection of bloodstream infections have been described in detail in the present review. Also, the future outlook and roadmap toward aptamer-based sensors and the challenges associated with the aptamer development have also been concluded in this review.
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Affiliation(s)
- Chaitali Singhal
- Aptamer Technology and Diagnostic Laboratory, Multidisciplinary Clinical and Translational Research Group, Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana 121001, India
| | - John G Bruno
- Nanohmics, Inc., Austin, Texas 78741, United States
| | - Ankur Kaushal
- Centre of Nanotechnology, Amity University, Manesar, Gurugram, Haryana 122413, India
| | - Tarun K Sharma
- Aptamer Technology and Diagnostic Laboratory, Multidisciplinary Clinical and Translational Research Group, Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana 121001, India
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5
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Li W. Prospective Application of Aptamer-based Assays and Therapeutics in Bloodstream Infections. Mini Rev Med Chem 2020; 20:831-840. [PMID: 32048971 DOI: 10.2174/1389557520666200212105813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 11/22/2022]
Abstract
Sepsis is still a severe health problem worldwide with high morbidity and mortality. Blood bacterial culture remains the gold standard for the detection of pathogenic bacteria in bloodstream infections, but it is time-consuming, and both the sophisticated equipment and well-trained personnel are required. Immunoassays and genetic diagnosis are expensive and limited to specificity and sensitivity. Aptamers are single-stranded deoxyribonucleic acid (ssDNA) and ribonucleic acid (RNA) oligonucleotide or peptide sequence generated in vitro based on the binding affinity of aptamer-target by a process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX). By taking several advantages over monoclonal antibodies and other conventional small-molecule therapeutics, such as high specificity and affinity, negligible batch-to-batch variation, flexible modification and production, thermal stability, low immunogenicity and lack of toxicity, aptamers are presently becoming promising novel diagnostic and therapeutic agents. This review describes the prospective application of aptamerbased laboratory diagnostic assays and therapeutics for pathogenic bacteria and toxins in bloodstream infections.
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Affiliation(s)
- Weibin Li
- Institute for Laboratory Medicine, 900th Hospital of Joint Service Corps, PLA, China.,Laboratory Department of Fujian Medical University, No. 156 North Xi-er Huan Road, Fuzhou City, Fujian Province, Fuzhou 350025, China
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6
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Jamil B, Atlas N, Qazi A, Uzair B. Theranostic Potential of Aptamers in Antimicrobial Chemotherapy. Nanotheranostics 2019. [DOI: 10.1007/978-3-030-29768-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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7
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Abraham K, Roueinfar M, Ponce AT, Lussier ME, Benson DB, Hong KL. In Vitro Selection and Characterization of a Single-Stranded DNA Aptamer Against the Herbicide Atrazine. ACS OMEGA 2018; 3:13576-13583. [PMID: 30411044 PMCID: PMC6217647 DOI: 10.1021/acsomega.8b01859] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/08/2018] [Indexed: 05/14/2023]
Abstract
Atrazine is an herbicide that is widely used in crop production at about 70 million pounds per year in the United States. Its widespread use has led to contamination of groundwater and other aquatic systems. It has resulted in many serious environmental and human health issues. This study focuses on the identification and characterization of a single-stranded DNA (ssDNA) aptamer that binds to atrazine. In this study, a variation of the systematic evolution of ligands by exponential enrichment (SELEX) process was used to identify an aptamer, which binds to atrazine with high affinity and specificity. This SELEX focused on inducing the aptamer's ability to change conformation upon binding to atrazine, and stringent negative target selections. After 12 rounds of in vitro selection, the ssDNA aptamer candidate R12.45 was chosen and truncated to obtain a 46-base sequence. The binding affinity, specificity, and structural characteristics of this truncated candidate was investigated by using isothermal titration calorimetry, circular dichroism (CD) analysis, SYBR Green I (SG) fluorescence displacement assays, and gold nanoparticles (AuNPs) colorimetric assays. The truncated R12.45 candidate aptamer bound to atrazine with high affinity (K d = 3.7 nM) and displayed low cross-binding activities on structurally related herbicides. In addition, CD analysis data indicated a target induced structural stabilization. Finally, SG assays and AuNPs assays showed nonconventional binding activities between the truncated R12.45 aptamer candidate and atrazine, which warrants future studies.
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Affiliation(s)
- Kevin
M. Abraham
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
| | - Mina Roueinfar
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
| | - Alex T. Ponce
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
| | - Mia E. Lussier
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
| | - Danica B. Benson
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
| | - Ka Lok Hong
- Department
of Pharmaceutical Sciences, Nesbitt School of Pharmacy, and Department of
Biology, College of Science and Engineering, Wilkes University, 84
W. South Street, Wilkes-Barre, Pennsylvania 18766, United States
- E-mail: . Phone: +1-570-408-4296. Fax: +1-570-408-4299
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8
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Aptamer-based fluorometric assay for direct identification of methicillin-resistant Staphylococcus aureus from clinical samples. J Microbiol Methods 2018; 153:92-98. [PMID: 30243766 DOI: 10.1016/j.mimet.2018.09.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022]
Abstract
Accurate and rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) is of important clinical significance. In this study, a novel aptamer-based fluorometric assay was developed for detection of MRSA in clinical samples by coupling with immunomagnetic separation. The S. aureus cells in clinical specimens were enriched by magnetic separation. Following lysis by staphylococcal lysin, the PBP2a proteins were released from S. aureus cells and detected by the aptamer-based fluorometric assay. Without lengthy period of bacteria cultivation in the traditional susceptibility testing, this test has an overall testing time of only 2 h with the detection limit of 2.63 × 103 and 1.38 × 103 CFU/mL in PBS and spiked nasal swab, respectively. Since it is simple, rapid and sensitive, this method could be used for the detection of MRSA in various clinical samples.
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9
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Pan Q, Luo F, Liu M, Zhang XL. Oligonucleotide aptamers: promising and powerful diagnostic and therapeutic tools for infectious diseases. J Infect 2018; 77:83-98. [PMID: 29746951 PMCID: PMC7112547 DOI: 10.1016/j.jinf.2018.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 01/02/2018] [Accepted: 04/08/2018] [Indexed: 12/21/2022]
Abstract
The entire human population is at risk of infectious diseases worldwide. Thus far, the diagnosis and treatment of human infectious diseases at the molecular and nanoscale levels have been extremely challenging tasks because of the lack of effective probes to identify and recognize biomarkers of pathogens. Oligonucleotide aptamers are a class of small nucleic acid ligands that are composed of single-stranded DNA (ssDNA) or RNA and act as affinity probes or molecular recognition elements for a variety of targets. These aptamers have an exciting potential for diagnose and/or treatment of specific diseases. In this review, we highlight areas where aptamers have been developed as diagnostic and therapeutic agents for both bacterial and viral infectious diseases as well as aptamer-based detection.
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Affiliation(s)
- Qin Pan
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Fengling Luo
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Min Liu
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Xiao-Lian Zhang
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China.
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10
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Frohnmeyer E, Frisch F, Falke S, Betzel C, Fischer M. Highly affine and selective aptamers against cholera toxin as capture elements in magnetic bead-based sandwich ELAA. J Biotechnol 2018; 269:35-42. [PMID: 29408200 DOI: 10.1016/j.jbiotec.2018.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/08/2017] [Accepted: 01/17/2018] [Indexed: 12/20/2022]
Abstract
Aptamers are single-stranded DNA or RNA oligonucleotides, which have been emerging as recognition elements in disease diagnostics and food control, including the detection of bacterial toxins. In this study, we employed the semi-automated just in time-selection to identify aptamers that bind to cholera toxin (CT) with high affinity and specificity. CT is the main virulence factor of Vibrio cholerae and the causative agent of the eponymous disease. For the selected aptamers, dissociation constants in the low nanomolar range (23-56 nM) were determined by fluorescence-based affinity chromatography and cross-reactivity against related proteins was evaluated by direct enzyme-linked aptamer assay (ELAA). Aptamer CT916 has a dissociation constant of 48.5 ± 0.5 nM and shows negligible binding to Shiga-like toxin 1B, protein A and BSA. This aptamer was chosen to develop a sandwich ELAA for the detection of CT from binding buffer and local tap water. Amine-C6- or biotin-modified CT916 was coupled to magnetic beads to serve as the capture element. Using an anti-CT polyclonal antibody as the reporter, detection limits of 2.1 ng/ml in buffer and 2.4 ng/ml in tap water, with a wide log-linear dynamic range from 1 ng/ml to 1000 ng/ml and 500 ng/ml, respectively, were achieved.
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Affiliation(s)
- Esther Frohnmeyer
- Hamburg School of Food Science, Hamburg, Germany; Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
| | - Farina Frisch
- Hamburg School of Food Science, Hamburg, Germany; Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
| | - Sven Falke
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
| | - Christian Betzel
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
| | - Markus Fischer
- Hamburg School of Food Science, Hamburg, Germany; Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
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Alizadeh N, Memar MY, Mehramuz B, Abibiglou SS, Hemmati F, Samadi Kafil H. Current advances in aptamer-assisted technologies for detecting bacterial and fungal toxins. J Appl Microbiol 2018; 124:644-651. [PMID: 29171901 DOI: 10.1111/jam.13650] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/20/2017] [Accepted: 11/15/2017] [Indexed: 01/01/2023]
Abstract
Infectious diseases are among the common leading causes of morbidity and mortality worldwide. Associated with the emergence of new infectious diseases, the increasing number of antimicrobial-resistant isolates presents a serious threat to public health and hospitalized patients. A microbial pathogen may elicit several host responses and use a variety of mechanisms to evade host defences. These methods and mechanisms include capsule, lipopolysaccharides or cell wall components, adhesions and toxins. Toxins inhibit phagocytosis, cause septic shock and host cell damages by binding to host surface receptors and invasion. Bacterial and fungal pathogens are able to apply many different toxin-dependent mechanisms to disturb signalling pathways and the structural integrity of host cells for establishing and maintaining infections Initial techniques for analysis of bacterial toxins were based on in vivo or in vitro assessments. There is a permanent demand for appropriate detection methods which are affordable, practical, careful, rapid, sensitive, efficient and economical. Aptamers are DNA or RNA oligonucleotides that are selected by systematic evolution of ligands using exponential enrichment (SELEX) methods and can be applied in diagnostic applications. This review provides an overview of aptamer-based methods as a novel approach for detecting toxins in bacterial and fungal pathogens.
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Affiliation(s)
- N Alizadeh
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - M Y Memar
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - B Mehramuz
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - S S Abibiglou
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - F Hemmati
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - H Samadi Kafil
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Iranian Center of Excellence in Health Management, Tabriz University of Medical Sciences, Tabriz, Iran
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Hong KL, Sooter LJ. In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against the Pesticide Fipronil and Sensitive Detection in River Water. Int J Mol Sci 2017; 19:ijms19010085. [PMID: 29283416 PMCID: PMC5796035 DOI: 10.3390/ijms19010085] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/12/2017] [Accepted: 12/25/2017] [Indexed: 12/26/2022] Open
Abstract
Fipronil is a commonly used insecticide that has been shown to have environmental and human health risks. The current standard methods of detection for fipronil and its metabolites, such as GC-MS, are time consuming and labor intensive. In this study, a variant of systematic evolution of ligands by exponential enrichment (SELEX), was utilized to identify the first single-stranded DNA (ssDNA) molecular recognition element (MRE) that binds to fipronil with high affinity (Kd = 48 ± 8 nM). The selected MRE displayed low cross binding activity on various environmentally relevant, structurally unrelated herbicides and pesticides, in addition to broad-spectrum binding activity on major metabolites of fipronil and a structurally similar pesticide in prepared river samples. Additionally, a proof-of-principle fluorescent detection assay was developed by using the selected ssDNA MRE as a signal-reporting element, with a limit of detection of 105 nM in a prepared river water sample.
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Affiliation(s)
- Ka L Hong
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, 84 W. South Street, Wilkes-Barre, PA 18766, USA.
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13
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Selection of Single-Stranded DNA Molecular Recognition Elements against Exotoxin A Using a Novel Decoy-SELEX Method and Sensitive Detection of Exotoxin A in Human Serum. BIOMED RESEARCH INTERNATIONAL 2015; 2015:417641. [PMID: 26636098 PMCID: PMC4655287 DOI: 10.1155/2015/417641] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/09/2015] [Accepted: 10/12/2015] [Indexed: 12/04/2022]
Abstract
Exotoxin A is one of the virulence factors of Pseudomonas aeruginosa, a bacterium that can cause infections resulting in adverse health outcomes and increased burden to health care systems. Current methods of diagnosing P. aeruginosa infections are time consuming and can require significant preparation of patient samples. This study utilized a novel variation of the Systematic Evolution of Ligand by Exponential Enrichment, Decoy-SELEX, to identify an Exotoxin A specific single-stranded DNA (ssDNA) molecular recognition element (MRE). Its emphasis is on increasing stringency in directing binding toward free target of interest and at the same time decreasing binding toward negative targets. A ssDNA MRE with specificity and affinity was identified after fourteen rounds of Decoy-SELEX. Utilizing surface plasmon resonance measurements, the determined equilibrium dissociation constant (Kd) of the MRE is between 4.2 µM and 4.5 µM, and is highly selective for Exotoxin A over negative targets. A ssDNA MRE modified sandwich enzyme-linked immunosorbent assay (ELISA) has been developed and achieved sensitive detection of Exotoxin A at nanomolar concentrations in human serum. This study has demonstrated the proof-of-principle of using a ssDNA MRE as a clinical diagnostic tool.
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14
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Single-Stranded DNA Aptamers against Pathogens and Toxins: Identification and Biosensing Applications. BIOMED RESEARCH INTERNATIONAL 2015. [PMID: 26199940 PMCID: PMC4493287 DOI: 10.1155/2015/419318] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Molecular recognition elements (MREs) can be short sequences of single-stranded DNA, RNA, small peptides, or antibody fragments. They can bind to user-defined targets with high affinity and specificity. There has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the Gold and Szostak laboratories. A large number of target specific nucleic acids MREs and their applications are currently in the literature. This review first describes the general methodologies used in identifying single-stranded DNA (ssDNA) aptamers. It then summarizes advancements in the identification and biosensing application of ssDNA aptamers specific for bacteria, viruses, their associated molecules, and selected chemical toxins. Lastly, an overview of the basic principles of ssDNA aptamer-based biosensors is discussed.
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