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Silva DP, Epstein HE, Vega Thurber RL. Best practices for generating and analyzing 16S rRNA amplicon data to track coral microbiome dynamics. Front Microbiol 2022; 13:1007877. [PMID: 36891260 PMCID: PMC9987214 DOI: 10.3389/fmicb.2022.1007877] [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: 07/31/2022] [Accepted: 12/30/2022] [Indexed: 02/22/2023] Open
Abstract
Over the past two decades, researchers have searched for methods to better understand the relationship between coral hosts and their microbiomes. Data on how coral-associated bacteria are involved in their host's responses to stressors that cause bleaching, disease, and other deleterious effects can elucidate how they may mediate, ameliorate, and exacerbate interactions between the coral and the surrounding environment. At the same time tracking coral bacteria dynamics can reveal previously undiscovered mechanisms of coral resilience, acclimatization, and evolutionary adaptation. Although modern techniques have reduced the cost of conducting high-throughput sequencing of coral microbes, to explore the composition, function, and dynamics of coral-associated bacteria, it is necessary that the entire procedure, from collection to sequencing, and subsequent analysis be carried out in an objective and effective way. Corals represent a difficult host with which to work, and unique steps in the process of microbiome assessment are necessary to avoid inaccuracies or unusable data in microbiome libraries, such as off-target amplification of host sequences. Here, we review, compare and contrast, and recommend methods for sample collection, preservation, and processing (e.g., DNA extraction) pipelines to best generate 16S amplicon libraries with the aim of tracking coral microbiome dynamics. We also discuss some basic quality assurance and general bioinformatic methods to analyze the diversity, composition, and taxonomic profiles of the microbiomes. This review aims to be a generalizable guide for researchers interested in starting and modifying the molecular biology aspects of coral microbiome research, highlighting best practices and tricks of the trade.
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Affiliation(s)
- Denise P Silva
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Hannah E Epstein
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
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Wilkinson AA, Jagu E, Ubych K, Coulthard S, Rushton AE, Kennefick J, Su Q, Neely RK, Fernandez-Trillo P. Site-Selective and Rewritable Labeling of DNA through Enzymatic, Reversible, and Click Chemistries. ACS CENTRAL SCIENCE 2020; 6:525-534. [PMID: 32342002 PMCID: PMC7181315 DOI: 10.1021/acscentsci.9b01023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Indexed: 05/02/2023]
Abstract
Current methods for bioconjugation rely on the introduction of stable linkers that lack the required versatility to perform sequential functionalizations. However, sequential manipulations are an increasing requirement in chemical biology because they can underpin multiple analyses of the same sample to provide a wider understanding of cell behavior. Here, we present a new method to site-selectively write, remove, and rewrite chemical functionality to a biomolecule, DNA in this case. Our method combines the precision and robustness of methyltransferase-directed labeling with the reversibility of acyl hydrazones and the efficiency of click chemistry. Underpinning the method is a new S-adenosyl-l-methionine derivative to site-selectively label DNA with a bifunctional chemical handle containing an acyl hydrazone-linker and a terminal azide. Functional tags are conjugated via the azide and can be removed (i.e., untagged) when needed at the acyl hydrazone via exchange with hydroxyl amine. The formed hydrazide-labeled DNA is a versatile intermediate that can be either rewritten to reset the original chemical handle or covalently reacted with a permanent tag. This ability to write, tag, untag, and permanently tag DNA is exploited to sequentially introduce two fluorescent dyes on DNA. Finally, we demonstrate the potential of the method by developing a protocol to sort labeled DNA using magnetic beads, with subsequent amplification of the sorted DNA sample for further analysis. The presented method opens new avenues for site-selective bioconjugation and should underpin integrative approaches in chemical biology where sequential functionalizations of the same sample are required.
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Affiliation(s)
- Andrew A Wilkinson
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Elodie Jagu
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Krystian Ubych
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Steven Coulthard
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Ashleigh E Rushton
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Jack Kennefick
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Qiang Su
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
| | - Robert K Neely
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, U.K., B15 2TT
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Masalov YK, Heydarov RN, Shashkov IA, Chebotar IV, Zasedatelev AS, Mayansky NA, Mikhailovich VM. Exogenous contaminating DNA in Taq polymerases: A method to avoid false-positive results when detecting the bla TEM gene. J Microbiol Methods 2019; 160:36-41. [PMID: 30904556 DOI: 10.1016/j.mimet.2019.03.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 11/24/2022]
Abstract
In the course of developing an assay to identify genes responsible for antibiotic resistance in gram-negative bacteria, it has been found that standard (not DNA-free) Taq DNA polymerases were contaminated with blaTEM gene fragments that varied in length and quantities. The complete blaTEM gene sequence was either absent or was detected in infinitesimal amounts. We developed an approach to avoid false-positive findings caused by contaminating blaTEM gene sequences in conventional polymerases. The method is based on selection of a target sequence to be detected within the blaTEM gene in such a way that the chosen sequence is amplified with primers incapable of amplifying contaminating DNA sequences of the polymerase.
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Affiliation(s)
- Yaroslav K Masalov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova Str., Moscow 119991, Russia
| | - Rustam N Heydarov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova Str., Moscow 119991, Russia
| | - Igor A Shashkov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova Str., Moscow 119991, Russia
| | - Igor V Chebotar
- National Medical Research Center for Children's Health, Ministry of Health, 2 Lomonosovsky Pros., Moscow 119991, Russia
| | - Alexander S Zasedatelev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova Str., Moscow 119991, Russia
| | - Nikolay A Mayansky
- National Medical Research Center for Children's Health, Ministry of Health, 2 Lomonosovsky Pros., Moscow 119991, Russia
| | - Vladimir M Mikhailovich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova Str., Moscow 119991, Russia.
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Deosarkar SD, Puyad AL, Shaikh UB, Solanke SS. Volumetric, rheological, and optical properties of hydroxylamine hydrochloride aqueous solutions containing NaCl, KCl, and NH4Cl at 30°C. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2014. [DOI: 10.1134/s0036024414040074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Champlot S, Berthelot C, Pruvost M, Bennett EA, Grange T, Geigl EM. An efficient multistrategy DNA decontamination procedure of PCR reagents for hypersensitive PCR applications. PLoS One 2010; 5. [PMID: 20927390 PMCID: PMC2946917 DOI: 10.1371/journal.pone.0013042] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 08/10/2010] [Indexed: 11/19/2022] Open
Abstract
Background PCR amplification of minute quantities of degraded DNA for ancient DNA research, forensic analyses, wildlife studies and ultrasensitive diagnostics is often hampered by contamination problems. The extent of these problems is inversely related to DNA concentration and target fragment size and concern (i) sample contamination, (ii) laboratory surface contamination, (iii) carry-over contamination, and (iv) contamination of reagents. Methodology/Principal Findings Here we performed a quantitative evaluation of current decontamination methods for these last three sources of contamination, and developed a new procedure to eliminate contaminating DNA contained in PCR reagents. We observed that most current decontamination methods are either not efficient enough to degrade short contaminating DNA molecules, rendered inefficient by the reagents themselves, or interfere with the PCR when used at doses high enough to eliminate these molecules. We also show that efficient reagent decontamination can be achieved by using a combination of treatments adapted to different reagent categories. Our procedure involves γ- and UV-irradiation and treatment with a mutant recombinant heat-labile double-strand specific DNase from the Antarctic shrimp Pandalus borealis. Optimal performance of these treatments is achieved in narrow experimental conditions that have been precisely analyzed and defined herein. Conclusions/Significance There is not a single decontamination method valid for all possible contamination sources occurring in PCR reagents and in the molecular biology laboratory and most common decontamination methods are not efficient enough to decontaminate short DNA fragments of low concentration. We developed a versatile multistrategy decontamination procedure for PCR reagents. We demonstrate that this procedure allows efficient reagent decontamination while preserving the efficiency of PCR amplification of minute quantities of DNA.
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Affiliation(s)
- Sophie Champlot
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
| | - Camille Berthelot
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
| | - Mélanie Pruvost
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
| | - E. Andrew Bennett
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
| | - Thierry Grange
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
| | - Eva-Maria Geigl
- Institut Jacques Monod, UMR7592 CNRS, Université Paris 7, Paris, France
- * E-mail:
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Borst A, Box ATA, Fluit AC. False-positive results and contamination in nucleic acid amplification assays: suggestions for a prevent and destroy strategy. Eur J Clin Microbiol Infect Dis 2004; 23:289-99. [PMID: 15015033 DOI: 10.1007/s10096-004-1100-1] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Contamination of samples with DNA is still a major problem in microbiology laboratories, despite the wide acceptance of PCR and other amplification techniques for the detection of frequently low amounts of target DNA. This review focuses on the implications of contamination in the diagnosis and research of infectious diseases, possible sources of contaminants, strategies for prevention and destruction, and quality control. Contamination of samples in diagnostic PCR can have far-reaching consequences for patients, as illustrated by several examples in this review. Furthermore, it appears that the (sometimes very unexpected) sources of contaminants are diverse (including water, reagents, disposables, sample carry over, and amplicon), and contaminants can also be introduced by unrelated activities in neighboring laboratories. Therefore, lack of communication between researchers using the same laboratory space can be considered a risk factor. Only a very limited number of multicenter quality control studies have been published so far, but these showed false-positive rates of 9-57%. The overall conclusion is that although nucleic acid amplification assays are basically useful both in research and in the clinic, their accuracy depends on awareness of risk factors and the proper use of procedures for the prevention of nucleic acid contamination. The discussion of prevention and destruction strategies included in this review may serve as a guide to help improve laboratory practices and reduce the number of false-positive amplification results.
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Affiliation(s)
- A Borst
- Eijkman-Winkler Center for Microbiology, Infectious Diseases and Inflammation, University Medical Center, PO Box 85500, 3508 GA Utrecht, The Netherlands
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McCormack JM, Sherman ML, Maurer DH. Quality control for DNA contamination in laboratories using PCR-based class II HLA typing methods. Hum Immunol 1997; 54:82-8. [PMID: 9154462 DOI: 10.1016/s0198-8859(97)00011-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Quality control (QC) in laboratories performing molecular histocompatibility class II typing often includes a polymerase chain reaction (PCR) approach for monitoring DNA contamination. An oligonucleotide primer set was designed, (RBQBf/RBQBr), which is specific for nonpolymorphic regions of the DR-B, DQ-B, and DP-B consensus sequences with an expected PCR product size of 81 bp. RBQBf/RBQBr detected genomic DNA from reference cell lines LWAGS and BM21 (50 to 100 picograms) as well as DR-B, DP-B, and DQ-B amplicon (1 copy). Additionally, RBQBf/RBQBr detected SSP products from routine DR-B and DQ-B typings. Validation studies employing controlled DNA contamination of laboratory surfaces revealed that increasing amounts of wipe test samples (5% to 20% v/v) were inhibitory to the wipe test PCR, whereas lower amounts (1% to 2%), or alternatively, a diluted wipe test sample, increased the sensitivity of the test and optimized the results. Collectively, this study describes a primer set, RBQBf/RBQBr, which detects both genomic DNA and DR-B, DQ-B, or DP-B amplicon and furthermore illustrates the necessity of routine testing for potential inhibitory factors that may be introduced into the wipe test PCR.
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Affiliation(s)
- J M McCormack
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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De la Viuda M, Fille M, Ruiz J, Aslanzadeh J. Use of AmpliWax to optimize amplicon sterilization by isopsoralen. J Clin Microbiol 1996; 34:3115-9. [PMID: 8940457 PMCID: PMC229468 DOI: 10.1128/jcm.34.12.3115-3119.1996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The photochemical inactivation of amplicons by isopsoralen (IP-10) has been suggested as a possible means to prevent PCR carryover contamination. To evaluate the technique, serial dilutions of amplicons (10(11) to 10(3)) from the Borrelia burgdorferi OSP A gene were amplified in the presence of 0, 25, 50, and 100 micrograms of IP-10 per ml for 45 cycles. The PCR products were exposed to UV light for 15 min to activate IP-10 and sterilize the amplicons. One microliter of each sterilized sample was reamplified for an additional 45 cycles. The PCR products were then resolved in an agarose gel, blotted onto a nylon membrane, and probed with an alkaline phosphatase-conjugated chemiluminescent probe. Although IP-10 at concentrations of 50 and 100 micrograms/ml effectively sterilized up to 10(11) amplicons, the compound was inhibitory to PCR. IP-10 at a concentration of 25 micrograms/ml had slight inhibitory effect on PCR and did not completely sterilized all of the amplicons. Therefore, in subsequent experiments AmpliWax was substituted for mineral oil, and PCR was performed on 10(9) to 10(3) amplicons as described above. Following the amplification, the PCR tubes were cooled to solidify the AmpliWax and inoculated with various concentrations of IP-10. With this technique, PCR products produced from as many as 10(9) target amplicons were effectively sterilized with 200 micrograms of IP-10 per ml. Similarly, the addition of IP-10 (50 micrograms/ml) before and after PCR was evaluated for the detection of B. burgdorferi in 62 ticks from a region of Southern Connecticut where the organism is highly endemic. PCR performed in the presence of 50 micrograms of IP-10 per ml detected B. burgdorferi-specific DNA in 17 of 62 ticks (27%) following gel electrophoresis and in 34 of 62 ticks (55%) following Southern blot hybridization of the PCR products. In contrast, post-PCR addition of IP-10 detected borrelia-specific DNA in 31 of 62 ticks (50%) following gel electrophoresis and in 46 of 62 ticks (64%) following Southern blot hybridization. We conclude that the replacement of mineral oil with AmpliWax can be useful in eliminating the inhibitory effects of IP-10 and other sterilizing agents for post-PCR sterilization of amplicons.
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Affiliation(s)
- M De la Viuda
- Department of Laboratory Medicine, University of Connecticut School of Medicine, Farmington 06030, USA
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Whelen AC, Persing DH. The role of nucleic acid amplification and detection in the clinical microbiology laboratory. Annu Rev Microbiol 1996; 50:349-73. [PMID: 8905084 DOI: 10.1146/annurev.micro.50.1.349] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Clinical microbiology is in the midst of a new era. Methodology that is based on nucleic acid detection has slowly appeared in the diagnostic laboratory, and is revolutionizing our ability to assist physicians in the diagnosis and management of patients suffering from infectious diseases. Much like the introduction of immunoassays built around hybridoma technology in the 1980s, considerable doubt and promise exist hand in hand in the 1990s. Conventional testing that is technically straight forward, informative, and timely will always be a part of clinical microbiology; however, considerable room for improvement exists with organisms/diseases for which laboratory methods are limited. Nucleic acid methodology will have its greatest and long-awaited impact in this arena.
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Affiliation(s)
- A C Whelen
- Microbiology Service, Brooke Army Medical Center, Fort Sam Houston, San Antonio, Texas 78234, USA
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