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Alves J, Vrieling M, Ring N, Yebra G, Pickering A, Prajsnar TK, Renshaw SA, Fitzgerald JR. Experimental evolution of Staphylococcus aureus in macrophages: dissection of a conditional adaptive trait promoting intracellular survival. mBio 2024; 15:e0034624. [PMID: 38682911 DOI: 10.1128/mbio.00346-24] [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: 02/05/2024] [Accepted: 03/26/2024] [Indexed: 05/01/2024] Open
Abstract
Staphylococcus aureus is a major pathogen associated with important diseases in humans and animals. Macrophages are a key component of the innate immune response to S. aureus infection and play a major role in disease outcomes. To investigate the adaptive evolution of S. aureus in response to macrophages, we developed an experimental infection assay. S. aureus strains representing major human epidemic clones were passaged many times in a macrophage cell line, accumulating mutations in an array of genomic loci. Phenotypic analysis revealed the emergence of a lineage exhibiting increased survival in macrophages and human blood, and resistance to vancomycin. The evolved lineage exhibited a previously undescribed small colony variant (SCV) phenotype characterized by hyper-pigmentation, which resulted from a missense mutation in rsbW. Notably, the novel SCV was a conditional adaptive trait that was unstable in nutrient-replete conditions in vitro, rapidly converting from hyper-pigmented SCV to a non-pigmented large colony variant via spontaneous sigB deletion events. Importantly, we identified similar deletions in the genome sequences of a limited number of clinical S. aureus isolates from public databases, indicating that related events may occur during clinical infection. Experimental infection of zebrafish did not reveal a difference in virulence between parent and novel SCV but demonstrated an in vivo fitness cost for the compensatory sigB deletion events. Taken together, we report an experimental evolutionary approach for investigating bacterial innate immune cell interactions, revealing a conditional adaptation that promotes S. aureus survival in macrophages and resistance to vancomycin. IMPORTANCE Staphylococcus aureus is an important human bacterial pathogen. The host response to S. aureus involves the production of innate immune cells such as macrophages which are important for fighting infection. Here we report a new model of experimental evolution for studying how S. aureus can evade killing by macrophages. We identified a novel adaptive phenotype that promotes survival in macrophages and blood and resistance to antibiotics. The phenotype is lost rapidly upon growth in nutrient-rich conditions via disruption of the alternative sigma factor sigB, revealing a conditional niche-specific fitness advantage. Genomic analysis of clinical isolates suggests similar adaptations may occur during human infections. Our model may be used broadly to identify adaptations of S. aureus to the innate immune response.
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Affiliation(s)
- Joana Alves
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
| | - Manouk Vrieling
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
| | - Natalie Ring
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
| | - Gonzalo Yebra
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
| | - Amy Pickering
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
| | - Tomasz K Prajsnar
- Florey Institute, Bateson Centre and Division of Clinical Medicine, School of Medicine and Population Health, Sheffield, United Kingdom
| | - Stephen A Renshaw
- Florey Institute, Bateson Centre and Division of Clinical Medicine, School of Medicine and Population Health, Sheffield, United Kingdom
| | - J Ross Fitzgerald
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, United Kingdom
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Kamal MM, Mia MS, Faruque MO, Rabby MG, Islam MN, Talukder MEK, Wani TA, Rahman MA, Hasan MM. In silico functional, structural and pathogenicity analysis of missense single nucleotide polymorphisms in human MCM6 gene. Sci Rep 2024; 14:11607. [PMID: 38773180 PMCID: PMC11109216 DOI: 10.1038/s41598-024-62299-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024] Open
Abstract
Single nucleotide polymorphisms (SNPs) are one of the most common determinants and potential biomarkers of human disease pathogenesis. SNPs could alter amino acid residues, leading to the loss of structural and functional integrity of the encoded protein. In humans, members of the minichromosome maintenance (MCM) family play a vital role in cell proliferation and have a significant impact on tumorigenesis. Among the MCM members, the molecular mechanism of how missense SNPs of minichromosome maintenance complex component 6 (MCM6) contribute to DNA replication and tumor pathogenesis is underexplored and needs to be elucidated. Hence, a series of sequence and structure-based computational tools were utilized to determine how mutations affect the corresponding MCM6 protein. From the dbSNP database, among 15,009 SNPs in the MCM6 gene, 642 missense SNPs (4.28%), 291 synonymous SNPs (1.94%), and 12,500 intron SNPs (83.28%) were observed. Out of the 642 missense SNPs, 33 were found to be deleterious during the SIFT analysis. Among these, 11 missense SNPs (I123S, R207C, R222C, L449F, V456M, D463G, H556Y, R602H, R633W, R658C, and P815T) were found as deleterious, probably damaging, affective and disease-associated. Then, I123S, R207C, R222C, V456M, D463G, R602H, R633W, and R658C missense SNPs were found to be highly harmful. Six missense SNPs (I123S, R207C, V456M, D463G, R602H, and R633W) had the potential to destabilize the corresponding protein as predicted by DynaMut2. Interestingly, five high-risk mutations (I123S, V456M, D463G, R602H, and R633W) were distributed in two domains (PF00493 and PF14551). During molecular dynamics simulations analysis, consistent fluctuation in RMSD and RMSF values, high Rg and hydrogen bonds in mutant proteins compared to wild-type revealed that these mutations might alter the protein structure and stability of the corresponding protein. Hence, the results from the analyses guide the exploration of the mechanism by which these missense SNPs of the MCM6 gene alter the structural integrity and functional properties of the protein, which could guide the identification of ways to minimize the harmful effects of these mutations in humans.
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Affiliation(s)
- Md Mostafa Kamal
- Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Md Sohel Mia
- Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Md Omar Faruque
- Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Md Golam Rabby
- Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Md Numan Islam
- Department of Food Engineering, North Pacific International University of Bangladesh, Dhaka, Bangladesh
| | | | - Tanveer A Wani
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, 11451, Riyadh, Saudi Arabia
| | - M Atikur Rahman
- Department of Biological Sciences, Alabama State University, 915 S Jackson St, Montgomery, AL, 36104, USA.
| | - Md Mahmudul Hasan
- Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
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Ribeiro R, Moreira JN, Goncalves J. Development of a new affinity maturation protocol for the construction of an internalizing anti-nucleolin antibody library. Sci Rep 2024; 14:10608. [PMID: 38719911 PMCID: PMC11079059 DOI: 10.1038/s41598-024-61230-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 05/02/2024] [Indexed: 05/12/2024] Open
Abstract
Over the last decades, monoclonal antibodies have substantially improved the treatment of several conditions. The continuous search for novel therapeutic targets and improvements in antibody's structure, demands for a constant optimization of their development. In this regard, modulation of an antibody's affinity to its target has been largely explored and culminated in the discovery and optimization of a variety of molecules. It involves the creation of antibody libraries and selection against the target of interest. In this work, we aimed at developing a novel protocol to be used for the affinity maturation of an antibody previously developed by our group. An antibody library was constructed using an in vivo random mutagenesis approach that, to our knowledge, has not been used before for antibody development. Then, a cell-based phage display selection protocol was designed to allow the fast and simple screening of antibody clones capable of being internalized by target cells. Next generation sequencing coupled with computer analysis provided an extensive characterization of the created library and post-selection pool, that can be used as a guide for future antibody development. With a single selection step, an enrichment in the mutated antibody library, given by a decrease in almost 50% in sequence diversity, was achieved, and structural information useful in the study of the antibody-target interaction in the future was obtained.
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Affiliation(s)
- Rita Ribeiro
- CNC-Center for Neurosciences and Cell Biology, Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine (Polo 1), University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, iMed.ULisboa - Research Institute for Medicines, University of Lisbon, Lisbon, Portugal
- Univ Coimbra-University of Coimbra, CIBB, Faculty of Pharmacy, Coimbra, Portugal
| | - João N Moreira
- CNC-Center for Neurosciences and Cell Biology, Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine (Polo 1), University of Coimbra, Coimbra, Portugal.
- Univ Coimbra-University of Coimbra, CIBB, Faculty of Pharmacy, Coimbra, Portugal.
| | - João Goncalves
- Faculty of Pharmacy, iMed.ULisboa - Research Institute for Medicines, University of Lisbon, Lisbon, Portugal.
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Wagner A. Genotype sampling for deep-learning assisted experimental mapping of a combinatorially complete fitness landscape. Bioinformatics 2024; 40:btae317. [PMID: 38745436 PMCID: PMC11132821 DOI: 10.1093/bioinformatics/btae317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/21/2024] [Accepted: 05/14/2024] [Indexed: 05/16/2024] Open
Abstract
MOTIVATION Experimental characterization of fitness landscapes, which map genotypes onto fitness, is important for both evolutionary biology and protein engineering. It faces a fundamental obstacle in the astronomical number of genotypes whose fitness needs to be measured for any one protein. Deep learning may help to predict the fitness of many genotypes from a smaller neural network training sample of genotypes with experimentally measured fitness. Here I use a recently published experimentally mapped fitness landscape of more than 260 000 protein genotypes to ask how such sampling is best performed. RESULTS I show that multilayer perceptrons, recurrent neural networks, convolutional networks, and transformers, can explain more than 90% of fitness variance in the data. In addition, 90% of this performance is reached with a training sample comprising merely ≈103 sequences. Generalization to unseen test data is best when training data is sampled randomly and uniformly, or sampled to minimize the number of synonymous sequences. In contrast, sampling to maximize sequence diversity or codon usage bias reduces performance substantially. These observations hold for more than one network architecture. Simple sampling strategies may perform best when training deep learning neural networks to map fitness landscapes from experimental data. AVAILABILITY AND IMPLEMENTATION The fitness landscape data analyzed here is publicly available as described previously (Papkou et al. 2023). All code used to analyze this landscape is publicly available at https://github.com/andreas-wagner-uzh/fitness_landscape_sampling.
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Affiliation(s)
- Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
- Swiss Institute of Bioinformatics, Quartier Sorge-Batiment Genopode,1015 Lausanne, Switzerland
- The Santa Fe Institute, Santa Fe, 87501 NM, United States
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5
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Ali F. Patterns of Change in Nucleotide Diversity Over Gene Length. Genome Biol Evol 2024; 16:evae078. [PMID: 38608148 DOI: 10.1093/gbe/evae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 03/26/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
Nucleotide diversity at a site is influenced by the relative strengths of neutral and selective population genetic processes. Therefore, attempts to estimate Effective population size based on the diversity of synonymous sites demand a better understanding of their selective constraints. The nucleotide diversity of a gene was previously found to correlate with its length. In this work, I measure nucleotide diversity at synonymous sites and uncover a pattern of low diversity towards the translation initiation site of a gene. The degree of reduction in diversity at the translation initiation site and the length of this region of reduced diversity can be quantified as "Effect Size" and "Effect Length" respectively, using parameters of an asymptotic regression model. Estimates of Effect Length across bacteria covaried with recombination rates as well as with a multitude of translation-associated traits such as the avoidance of mRNA secondary structure around translation initiation site, the number of rRNAs, and relative codon usage of ribosomal genes. Evolutionary simulations under purifying selection reproduce the observed patterns and diversity-length correlation and highlight that selective constraints on the 5'-region of a gene may be more extensive than previously believed. These results have implications for the estimation of effective population size, and relative mutation rates, and for genome scans of genes under positive selection based on "silent-site" diversity.
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Affiliation(s)
- Farhan Ali
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281, USA
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Nkurikiyimfura O, Waheed A, Fang H, Yuan X, Chen L, Wang YP, Lu G, Zhan J, Yang L. Fitness difference between two synonymous mutations of Phytophthora infestans ATP6 gene. BMC Ecol Evol 2024; 24:36. [PMID: 38494489 PMCID: PMC10946160 DOI: 10.1186/s12862-024-02223-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 03/11/2024] [Indexed: 03/19/2024] Open
Abstract
BACKGROUND Sequence variation produced by mutation provides the ultimate source of natural selection for species adaptation. Unlike nonsynonymous mutation, synonymous mutations are generally considered to be selectively neutral but accumulating evidence suggests they also contribute to species adaptation by regulating the flow of genetic information and the development of functional traits. In this study, we analysed sequence characteristics of ATP6, a housekeeping gene from 139 Phytophthora infestans isolates, and compared the fitness components including metabolic rate, temperature sensitivity, aggressiveness, and fungicide tolerance among synonymous mutations. RESULTS We found that the housekeeping gene exhibited low genetic variation and was represented by two major synonymous mutants at similar frequency (0.496 and 0.468, respectively). The two synonymous mutants were generated by a single nucleotide substitution but differed significantly in fitness as well as temperature-mediated spatial distribution and expression. The synonymous mutant ending in AT was more common in cold regions and was more expressed at lower experimental temperature than the synonymous mutant ending in GC and vice versa. CONCLUSION Our results are consistent with the argument that synonymous mutations can modulate the adaptive evolution of species including pathogens and have important implications for sustainable disease management, especially under climate change.
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Affiliation(s)
- Oswald Nkurikiyimfura
- Institute of Plant Virology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Abdul Waheed
- Institute of Plant Virology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Hanmei Fang
- Institute of Plant Virology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiaoxian Yuan
- Institute of Plant Virology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Lixia Chen
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou, 350108, China
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Yan-Ping Wang
- College of Chemistry and Life Sciences, Sichuan Provincial Key Laboratory for Development and Utilization of Characteristic Horticultural Biological Resources, Chengdu Normal University, Chengdu, Sichuan, 611130, China
| | - Guodong Lu
- Department of Plant Pathology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Jiasui Zhan
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, 75007, Sweden.
| | - Lina Yang
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou, 350108, China.
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McGrath KM, Russell SJ, Fer E, Garmendia E, Hosgel A, Baltrus DA, Kaçar B. Fitness benefits of a synonymous substitution in an ancient EF-Tu gene depend on the genetic background. J Bacteriol 2024; 206:e0032923. [PMID: 38289064 PMCID: PMC10882980 DOI: 10.1128/jb.00329-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/05/2024] [Indexed: 02/13/2024] Open
Abstract
Synonymous mutations are changes to DNA sequence, which occur within translated genes but which do not affect the protein sequence. Although often referred to as silent mutations, evidence suggests that synonymous mutations can affect gene expression, mRNA stability, and even translation efficiency. A collection of both experimental and bioinformatic data has shown that synonymous mutations can impact cell phenotype, yet less is known about the molecular mechanisms and potential of beneficial or adaptive effects of such changes within evolved populations. Here, we report a beneficial synonymous mutation acquired via experimental evolution in an essential gene variant encoding the translation elongation factor protein EF-Tu. We demonstrate that this particular synonymous mutation increases EF-Tu mRNA and protein levels as well as global polysome abundance on RNA transcripts. Although presence of the synonymous mutation is clearly causative of such changes, we also demonstrate that fitness benefits are highly contingent on other potentiating mutations present within the genetic background in which the mutation arose. Our results underscore the importance of beneficial synonymous mutations, especially those that affect levels of proteins that are key for cellular processes.IMPORTANCEThis study explores the degree to which synonymous mutations in essential genes can influence adaptation in bacteria. An experimental system whereby an Escherichia coli strain harboring an engineered translation protein elongation factor-Tu (EF-Tu) was subjected to laboratory evolution. We find that a synonymous mutation acquired on the gene encoding for EF-Tu is conditionally beneficial for bacterial fitness. Our findings provide insight into the importance of the genetic background when a synonymous substitution is favored by natural selection and how such changes have the potential to impact evolution when critical cellular processes are involved.
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Affiliation(s)
- Kaitlyn M. McGrath
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Steven J. Russell
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbial Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eva Garmendia
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Ali Hosgel
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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8
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Zurita AMI, Kyriazis CC, Lohmueller KE. The impact of non-neutral synonymous mutations when inferring selection on non-synonymous mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.07.579314. [PMID: 38370782 PMCID: PMC10871344 DOI: 10.1101/2024.02.07.579314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
The distribution of fitness effects (DFE) describes the proportions of new mutations that have different effects on reproductive fitness. Accurate measurements of the DFE are important because the DFE is a fundamental parameter in evolutionary genetics and has implications for our understanding of other phenomena like complex disease or inbreeding depression. Current computational methods to infer the DFE for nonsynonymous mutations from natural variation first estimate demographic parameters from synonymous variants to control for the effects of demography and background selection. Then, conditional on these parameters, the DFE is then inferred for nonsynonymous mutations. This approach relies on the assumption that synonymous variants are neutrally evolving. However, some evidence points toward synonymous mutations having measurable effects on fitness. To test whether selection on synonymous mutations affects inference of the DFE of nonsynonymous mutations, we simulated several possible models of selection on synonymous mutations using SLiM and attempted to recover the DFE of nonsynonymous mutations using Fit∂a∂i, a common method for DFE inference. Our results show that the presence of selection on synonymous variants leads to incorrect inferences of recent population growth. Furthermore, under certain parameter combinations, inferences of the DFE can have an inflated proportion of highly deleterious nonsynonymous mutations. However, this bias can be eliminated if the correct demographic parameters are used for DFE inference instead of the biased ones inferred from synonymous variants. Our work demonstrates how unmodeled selection on synonymous mutations may affect downstream inferences of the DFE.
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Affiliation(s)
- Aina Martinez I Zurita
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Christopher C Kyriazis
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, USA
| | - Kirk E Lohmueller
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, USA
- Interdepartmental Program in Bioinformatics, University of California, Los Angeles, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, USA
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9
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Waneka G, Pate B, Monroe JG, Sloan DB. Investigating low frequency somatic mutations in Arabidopsis with Duplex Sequencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578196. [PMID: 38352550 PMCID: PMC10862904 DOI: 10.1101/2024.01.31.578196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Mutations are the source of novel genetic diversity but can also lead to disease and maladaptation. The conventional view is that mutations occur randomly with respect to their environment-specific fitness consequences. However, intragenomic mutation rates can vary dramatically due to transcription coupled repair and based on local epigenomic modifications, which are non-uniformly distributed across genomes. One sequence feature associated with decreased mutation is higher expression level, which can vary depending on environmental cues. To understand whether the association between expression level and mutation rate creates a systematic relationship with environment-specific fitness effects, we perturbed expression through a heat treatment in Arabidopsis thaliana. We quantified gene expression to identify differentially expressed genes, which we then targeted for mutation detection using Duplex Sequencing. This approach provided a highly accurate measurement of the frequency of rare somatic mutations in vegetative plant tissues, which has been a recent source of uncertainty in plant mutation research. We included mutant lines lacking mismatch repair (MMR) and base excision repair (BER) capabilities to understand how repair mechanisms may drive biased mutation accumulation. We found wild type (WT) and BER mutant mutation frequencies to be very low (mean variant frequency 1.8×10-8 and 2.6×10-8, respectively), while MMR mutant frequencies were significantly elevated (1.13×10-6). These results show that somatic variant frequencies are extremely low in WT plants, indicating that larger datasets will be needed to address the fundamental evolutionary question as to whether environmental change leads to gene-specific changes in mutation rate.
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Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Braden Pate
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - J Grey Monroe
- Department of Plant Sciences, University of California, Davis, Davis, CA USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
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Surve SV, Shinde DB, Fernandes JM, Sharma S, Vijayvargiya M, Kadam K, Kulkarni R. Laboratory domestication of Lactiplantibacillus plantarum alters some phenotypic traits but causes non-novel genomic impact. J Appl Microbiol 2024; 135:lxae035. [PMID: 38341274 DOI: 10.1093/jambio/lxae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/17/2024] [Accepted: 02/08/2024] [Indexed: 02/12/2024]
Abstract
AIMS Laboratory domestication has been negligibly examined in lactic acid bacteria (LAB). Lactiplantibacillus plantarum is a highly studied and industrially relevant LAB. Here, we passaged L. plantarum JGR2 in a complex medium to study the effects of domestication on the phenotypic properties and the acquisition of mutations. METHODS AND RESULTS Lactiplantibacillus plantarum JGR2 was passaged in mMRS medium (deMan Rogossa Sharpe supplemented with 0.05% w/v L-cysteine) in three parallel populations for 70 days. One pure culture from each population was studied for various phenotypic properties and genomic alterations. Auto-aggregation of the evolved strains was significantly reduced, and lactic acid production and ethanol tolerance were increased. Other probiotic properties and antibiotic sensitivity were not altered. Conserved synonymous and non-synonymous mutations were observed in mobile element proteins (transposases), β-galactosidase, and phosphoketolases in all three isolates. The evolved strains lost all the repeat regions and some of the functions associated with them. Most of the conserved mutations were found in the genomes of other wild-type strains available in a public database, indicating the non-novel genomic impact of laboratory passaging. CONCLUSIONS Laboratory domestication can affect the phenotypic and genotypic traits of L. plantarum and similar studies are necessary for other important species of LAB.
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Affiliation(s)
- Sarvesh V Surve
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Dasharath B Shinde
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Joyleen M Fernandes
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Sharoni Sharma
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Monty Vijayvargiya
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Komal Kadam
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Ram Kulkarni
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
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11
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Wei L, Xiao W, Chen B, Zou Z, Zhu J, Li D, Yu J, Yang H. Single nucleotide polymorphisms in the MRFs gene family associated with growth in Nile tilapia. Mol Biol Rep 2024; 51:128. [PMID: 38236311 DOI: 10.1007/s11033-023-08955-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/17/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND Muscle occupies most of the fish body, promoting the proliferation of fish muscle fibers can facilitate rapid growth and increase the body weight of fish. Some studiesSeveral previous suggest that Myogenic regulatory factors (MRFs) play an important role in the growth of fish. OBJECTIVE To investigate the association between the polymorphism of MRFs gene family and growth traits in Nile tilapia (Oreochromis niloticus), get more molecular markers for growth. METHODS Amplified the Nile tilapia MRFs family gene, including Myogenic determination 1 (Myod1), Myogenic determination 2 (Myod2), Myogenin (Myog), Myogenic factor 5 (Myf5), and Myogenic factor 6 (Myf6), single nucleotide polymorphism (SNP) were screened by Sanger sequencing. RESULTS A total of 16 SNP loci were screened, including six for Myf5, six for Myf6, one for Myog, one for Myod1 and two for Myod2. The growth traits were analyzed in relation to these 16 SNP loci, and the results indicated significant associations between all 16 SNP loci and the growth traits (P < 0.05). The linkage disequilibrium analysis revealed that D1 and D2 diplotypes of Myf5 gene, E1, E2, E3 and E4 of Myf6 gene, and F1 diplotype of Myod2 gene were significantly associated with superior growth traits. CONCLUSION There were 6, 6, 1, 1 and 2 growth-related molecular markers in Myf5, Myf6, Myog, Myod1 and Myod2 genes, respectively, which could be applied to the breeding of Nile tilapia.
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Affiliation(s)
- Longjie Wei
- Wuxi Fisheries College, Nanjing Agricultural University, 214081, Wuxi, China
| | - Wei Xiao
- Wuxi Fisheries College, Nanjing Agricultural University, 214081, Wuxi, China.
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China.
| | - Binglin Chen
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China
| | - Zhiying Zou
- Wuxi Fisheries College, Nanjing Agricultural University, 214081, Wuxi, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China
| | - Jinglin Zhu
- Wuxi Fisheries College, Nanjing Agricultural University, 214081, Wuxi, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China
| | - Dayu Li
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China
| | - Jie Yu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China
| | - Hong Yang
- Wuxi Fisheries College, Nanjing Agricultural University, 214081, Wuxi, China.
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, 214081, Wuxi, China.
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12
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Liu Q, Cai YD, Ma L, Liu H, Linghu T, Guo S, Wei S, Song F, Tian L, Cai W, Li H. Relaxed purifying selection pressure drives accelerated and dynamic gene rearrangements in thrips (Insecta: Thysanoptera) mitochondrial genomes. Int J Biol Macromol 2023; 253:126742. [PMID: 37689283 DOI: 10.1016/j.ijbiomac.2023.126742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/06/2023] [Accepted: 08/26/2023] [Indexed: 09/11/2023]
Abstract
Insect mitochondrial genomes (mitogenome) generally present a typical gene order, which is considered as the ancestral arrangement. All sequenced mitogenomes in the Thysanoptera display high levels of gene rearrangement. Due to limited number of thrips mitogenomes sequenced, how gene rearrangement may be shaped by evolution remain unclear. Here, we analyzed 33 thrips mitogenomes, including 14 newly sequenced. These mitogenomes were diverse in organization, nucleotides substitution and gene arrangements. We found 28 highly rearranged gene orders with the breakpoints of gene rearrangements from 25 to 33. Reconstruction of the ancestors mitochondrial gene arrangements states indicated that Tubulifera have more complex pathways than Terebrantia in the gene order evolution. Molecular calibration estimated that divergence of two suborders occurred in the middle Triassic while the radiation of thrips was associated with the arose and flourish of angiosperm. Our evolutionary hypothesis testing suggests that relaxation of selection pressure enabled the early phase of Thysanoptera evolution, followed by a stronger selective pressure fixed diversification. Our analyses found gene inversion increases the nonsynonymous substitution rates and provide an evolutionary hypothesis driving the diverse gene orders.
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Affiliation(s)
- Qiaoqiao Liu
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Yao D Cai
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, One Shields Ave, Davis, CA 95616, USA
| | - Ling Ma
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Hangrui Liu
- Department of Physics and Astronomy, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Tianye Linghu
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Shaokun Guo
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests of Ministry of Agriculture and Rural Affairs, Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Shujun Wei
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Fan Song
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Li Tian
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Wanzhi Cai
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Hu Li
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China.
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13
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Yang B, Cheng Z, Luo L, Cheng K, Gan S, Shi Y, Liu C, Wang D. Comparative analysis of codon usage patterns of Plasmodium helical interspersed subtelomeric (PHIST) proteins. Front Microbiol 2023; 14:1320060. [PMID: 38156001 PMCID: PMC10752978 DOI: 10.3389/fmicb.2023.1320060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/28/2023] [Indexed: 12/30/2023] Open
Abstract
Background Plasmodium falciparum is a protozoan parasite that causes the most severe form of malaria in humans worldwide, which is predominantly found in sub-Saharan Africa, where it is responsible for the majority of malaria-related deaths. Plasmodium helical interspersed subtelomeric (PHIST) proteins are a family of proteins, with a conserved PHIST domain, which are typically located at the subtelomeric regions of the Plasmodium falciparum chromosomes and play crucial roles in the interaction between the parasite and its human host, such as cytoadherence, immune evasion, and host cell remodeling. However, the specific utilization of synonymous codons by PHIST proteins in Plasmodium falciparum is still unknown. Methods Codon usage bias (CUB) refers to the unequal usage of synonymous codons during translation, resulting in over- or underrepresentation of certain nucleotide patterns. This imbalance in CUB can impact various cellular processes, including protein expression levels and genetic variation. To investigate this, the CUB of 88 PHIST protein coding sequences (CDSs) from 5 subgroups were analyzed in this study. Results The results showed that both codon base composition and relative synonymous codon usage (RSCU) analysis identified a higher occurrence of AT-ended codons (AGA and UUA) in PHIST proteins of Plasmodium falciparum. The average effective number of codons (ENC) for these PHIST proteins was 36.69, indicating a weak codon preference among them, as it was greater than 35. Additionally, the correlation analysis among codon base composition (GC1, GC2, GC3, GCs), codon adaptation index (CAI), codon bias index (CBI), frequency of optimal codons (FOP), ENC, general average hydropathicity (GRAVY), aromaticity (AROMO), length of synonymous codons (L_sym), and length of amino acids (L_aa) revealed the influence of base composition and codon usage indices on codon usage bias, with GC1 having a significant impact in this study. Furthermore, the neutrality plot analysis, PR2-bias plot analysis, and ENC-GC3 plot analysis provided additional evidence that natural selection plays a crucial role in determining codon bias in PHIST proteins. Conclusion In conclusion, this study has enhanced our understanding of the characteristics of codon usage and genetic evolution in PHIST proteins, thereby providing data foundation for further research on antimalarial drugs or vaccines.
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Affiliation(s)
- Baoling Yang
- College of Basic Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Ziwen Cheng
- College of Basic Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Like Luo
- College of Basic Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Kuo Cheng
- College of Basic Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Shengqi Gan
- College of Animal Husbandry and Veterinary Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Yuyi Shi
- College of Animal Husbandry and Veterinary Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Che Liu
- College of Animal Husbandry and Veterinary Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Dawei Wang
- College of Animal Husbandry and Veterinary Medicine, Jinzhou Medical University, Jinzhou, Liaoning Province, China
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14
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Bajaj P, Bhasin M, Varadarajan R. Molecular bases for strong phenotypic effects of single synonymous codon substitutions in the E. coli ccdB toxin gene. BMC Genomics 2023; 24:732. [PMID: 38049728 PMCID: PMC10694988 DOI: 10.1186/s12864-023-09817-0] [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: 06/18/2023] [Accepted: 11/18/2023] [Indexed: 12/06/2023] Open
Abstract
BACKGROUND Single synonymous codon mutations typically have only minor or no effects on gene function. Here, we estimate the effects on cell growth of ~ 200 single synonymous codon mutations in an operonic context by mutating almost all positions of ccdB, the 101-residue long cytotoxin of the ccdAB Toxin-Antitoxin (TA) operon to most degenerate codons. Phenotypes were assayed by transforming the mutant library into CcdB sensitive and resistant E. coli strains, isolating plasmid pools, and subjecting them to deep sequencing. Since autoregulation is a hallmark of TA operons, phenotypes obtained for ccdB synonymous mutants after transformation in a RelE toxin reporter strain followed by deep sequencing provided information on the amount of CcdAB complex formed. RESULTS Synonymous mutations in the N-terminal region involved in translation initiation showed the strongest non-neutral phenotypic effects. We observe an interplay of numerous factors, namely, location of the codon, codon usage, t-RNA abundance, formation of anti-Shine Dalgarno sequences, predicted transcript secondary structure, and evolutionary conservation in determining phenotypic effects of ccdB synonymous mutations. Incorporation of an N-terminal, hyperactive synonymous mutation, in the background of the single synonymous codon mutant library sufficiently increased translation initiation, such that mutational effects on either folding or termination of translation became more apparent. Introduction of putative pause sites not only affects the translational rate, but might also alter the folding kinetics of the protein in vivo. CONCLUSION In summary, the study provides novel insights into diverse mechanisms by which synonymous mutations modulate gene function. This information is useful in optimizing heterologous gene expression in E. coli and understanding the molecular bases for alteration in gene expression that arise due to synonymous mutations.
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Affiliation(s)
- Priyanka Bajaj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- Present address: Department of Bioengineering and Therapeutic Sciences, University of CA - San Francisco, San Francisco, CA, 94158, USA
| | - Munmun Bhasin
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.
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15
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Wang D, Yang B. Analysis of codon usage bias of thioredoxin in apicomplexan protozoa. Parasit Vectors 2023; 16:431. [PMID: 37990340 PMCID: PMC10664530 DOI: 10.1186/s13071-023-06002-w] [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: 06/26/2023] [Accepted: 10/06/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND Apicomplexan protozoa are a diverse group of obligate intracellular parasites causing many diseases that affect humans and animals, such as malaria, toxoplasmosis, and cryptosporidiosis. Apicomplexan protozoa possess unique thioredoxins (Trxs) that have been shown to regulate various cellular processes including metabolic redox regulation, parasite survival, and host immune evasion. However, it is still unknown how synonymous codons are used by apicomplexan protozoa Trxs. METHODS Codon usage bias (CUB) is the unequal usage of synonymous codons during translation which leads to the over- or underrepresentation of certain nucleotide patterns. This imbalance in CUB can impact a variety of cellular processes including protein expression levels and genetic variation. This study analyzed the CUB of 32 Trx coding sequences (CDS) from 11 apicomplexan protozoa. RESULTS The results showed that both codon base composition and relative synonymous codon usage (RSCU) analysis revealed that AT-ended codons were more frequently used in Cryptosporidium spp. and Plasmodium spp., while the Eimeria spp., Babesia spp., Hammondia hammondi, Neospora caninum, and Toxoplasma gondii tended to end in G/C. The average effective number of codon (ENC) value of these apicomplexan protozoa is 46.59, which is > 35, indicating a weak codon preference among apicomplexan protozoa Trxs. Furthermore, the correlation analysis among codon base composition (GC1, GC2, GC3, GCs), codon adaptation index (CAI), codon bias index (CBI), frequency of optimal codons (FOP), ENC, general average hydropathicity (GRAVY), aromaticity (AROMO), length of synonymous codons (L_sym), and length of amino acids (L_aa) indicated the influence of base composition and codon usage indices on CUB. Additionally, the neutrality plot analysis, PR2-bias plot analysis, and ENC-GC3 plot analysis further demonstrated that natural selection plays an important role in apicomplexan protozoa Trxs codon bias. CONCLUSIONS In conclusion, this study increased the understanding of codon usage characteristics and genetic evolution of apicomplexan protozoa Trxs, which expanded new ideas for vaccine and drug research.
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Affiliation(s)
- Dawei Wang
- Jinzhou Medical University, Jinzhou, 121000, Liaoning Province, China
| | - Baoling Yang
- Jinzhou Medical University, Jinzhou, 121000, Liaoning Province, China.
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16
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Guo F, Yang J, Abd El-Aty AM, Wang R, Ju X. Base composition, adaptation, and evolution of goose astroviruses: codon-based investigation. Poult Sci 2023; 102:103029. [PMID: 37713803 PMCID: PMC10511809 DOI: 10.1016/j.psj.2023.103029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/24/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023] Open
Abstract
Goose astroviruses (GoAstVs) are causative agents that account for fatal infection of goslings characterized by visceral urate deposition, resulting in severe economic losses in major goose-producing regions in China since 2017. In this study, we sought to unravel the intrinsic properties associated with adaptation and evolution in the host environment of GoAstVs. Consistent results from phylogenetic analysis and correspondence analysis performed on the codon usage patterns (CUPs) reveal 2 clusters of GoAstVs, namely, GoAstV-1 and GoAstV-2. However, multiple similar compositional characteristics were found, despite the high divergence between GoAstV-1 and GoAstV-2. Studies on the base composition of GoAstVs reveal an A/U bias, indicating a compositional constraint, while natural selection prevailed in determining the CUPs in the virus genome based on our neutrality plot analysis, reflecting high adaptive pressure to fit the host environment. Codon adaptation index (CAI) analysis revealed a higher degree of fitness to the CUPs of the corresponding host for GoAstVs than avian influenza virus and betacoronaviruses, which may be a favorable factor contributing to the high pathogenicity and wide distribution of GoAstVs in goslings. In addition, GoAstVs were less adapted to ducks and chickens, with significantly lower CAI values than to geese, which may be a reason for the different prevalence of GoAstVs among these species. Extensive investigations on dinucleotide distribution revealed a significant suppression of the CpG and UpA motifs in the virus genome, which may facilitate adaptation to the host's innate immune system by evading surveillance. In addition, our study reported the trends of increasing fitness to the host's microenvironment for GoAstVs through increasing adaptation to host CUPs and ongoing reduction of CpG motifs in the virus genome. The present analysis deepens our understanding of the basic biology, pathogenesis, adaptation and evolutionary pattern of GoAstVs, and contributes to the development of novel antiviral strategies.
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Affiliation(s)
- Fucheng Guo
- Department of Veterinary Medicine, College of Coastal Agricultural Science, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Jinjin Yang
- Technology Center of Zhanjiang Customs District, Zhanjiang, 524000, Guangdong, China
| | - A M Abd El-Aty
- Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt; Department of Medical Pharmacology, Medical Faculty, Ataturk University, Erzurum 25240, Turkey
| | - Ruichen Wang
- Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing 102206, China
| | - Xianghong Ju
- Department of Veterinary Medicine, College of Coastal Agricultural Science, Guangdong Ocean University, Zhanjiang, 524088, China; Marine Medical Research and Development Centre, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China.
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17
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Pentz JT, MacGillivray K, DuBose JG, Conlin PL, Reinhardt E, Libby E, Ratcliff WC. Evolutionary consequences of nascent multicellular life cycles. eLife 2023; 12:e84336. [PMID: 37889142 PMCID: PMC10611430 DOI: 10.7554/elife.84336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 10/08/2023] [Indexed: 10/28/2023] Open
Abstract
A key step in the evolutionary transition to multicellularity is the origin of multicellular groups as biological individuals capable of adaptation. Comparative work, supported by theory, suggests clonal development should facilitate this transition, although this hypothesis has never been tested in a single model system. We evolved 20 replicate populations of otherwise isogenic clonally reproducing 'snowflake' yeast (Δace2/∆ace2) and aggregative 'floc' yeast (GAL1p::FLO1 /GAL1p::FLO1) with daily selection for rapid growth in liquid media, which favors faster cell division, followed by selection for rapid sedimentation, which favors larger multicellular groups. While both genotypes adapted to this regime, growing faster and having higher survival during the group-selection phase, there was a stark difference in evolutionary dynamics. Aggregative floc yeast obtained nearly all their increased fitness from faster growth, not improved group survival; indicating that selection acted primarily at the level of cells. In contrast, clonal snowflake yeast mainly benefited from higher group-dependent fitness, indicating a shift in the level of Darwinian individuality from cells to groups. Through genome sequencing and mathematical modeling, we show that the genetic bottlenecks in a clonal life cycle also drive much higher rates of genetic drift-a result with complex implications for this evolutionary transition. Our results highlight the central role that early multicellular life cycles play in the process of multicellular adaptation.
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Affiliation(s)
| | - Kathryn MacGillivray
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
- Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of TechnologyAtlantaUnited States
| | - James G DuBose
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Peter L Conlin
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Emma Reinhardt
- Department of Biology, University of North Carolina at Chapel HillChapel HillUnited States
| | | | - William C Ratcliff
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
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18
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McGrath KM, Russell SJ, Fer E, Garmendia E, Hosgel A, Baltrus DA, Kaçar B. A beneficial synonymous substitution in EF-Tu is contingent on genetic background. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.555949. [PMID: 37886545 PMCID: PMC10602032 DOI: 10.1101/2023.09.06.555949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Synonymous mutations are changes to DNA sequence that occur within translated genes but which do not affect the protein sequence. Although often referred to as silent mutations, evidence suggests that synonymous mutations can affect gene expression, mRNA stability, and even translation efficiency. A collection of both experimental and bioinformatic data has shown that synonymous mutations can impact cell phenotype, yet less is known about the molecular mechanisms and potential of beneficial or adaptive effects of such changes within evolved populations. Here, we report a beneficial synonymous mutation acquired via experimental evolution in an essential gene variant encoding the translation Elongation Factor protein EF-Tu. We demonstrate that this particular synonymous mutation increases EF-Tu mRNA and protein levels, as well as the polysome abundance on global transcripts. Although presence of the synonymous mutation is clearly causative of such changes, we also demonstrate that fitness benefits are highly contingent on other potentiating mutations present within the genetic background in which the mutation arose. Our results underscore the importance of beneficial synonymous mutations, especially those that affect levels of proteins that are key for cellular processes.
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Affiliation(s)
- Kaitlyn M. McGrath
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
- School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Steven J. Russell
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Evrim Fer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Microbial Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Eva Garmendia
- Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden
| | - Ali Hosgel
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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19
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Majdalani N, Chattopadhyay M, Keller C, Gottesman S. Lack of polyamines leads to cotranslational degradation of the general stress factor RpoS in Escherichia coli. J Biol Chem 2023; 299:104943. [PMID: 37343699 PMCID: PMC10372455 DOI: 10.1016/j.jbc.2023.104943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
The specialized sigma factor RpoS mediates a general stress response in Escherichia coli and related bacteria, activating promoters that allow cells to survive stationary phase and many stresses. RpoS synthesis and stability are regulated at multiple levels. Translation of RpoS is positively regulated by multiple small RNAs in response to stress. Degradation of RpoS, dependent upon the adaptor protein RssB, is rapid during exponential growth and ceases upon starvation or other stresses, increasing accumulation of RpoS. E. coli carrying mutations that block the synthesis of polyamines were previously found to have low levels of RpoS, while levels increased rapidly when polyamines were added. We have used a series of reporters to examine the basis for the lack of RpoS in polyamine-deficient cells. The polyamine requirement was independent of small RNA-mediated positive regulation of RpoS translation. Mutations in rssB stabilize RpoS and significantly bypassed the polyamine deficit, suggesting that lack of polyamines might lead to rapid RpoS degradation. However, rates of degradation of mature RpoS were unaffected by polyamine availability. Codon optimization in rpoS partially relieved the polyamine dependence, suggesting a defect in RpoS translation in the absence of polyamines. Consistent with this, a hyperproofreading allele of ribosomal protein S12, encoded by rpsL, showed a decrease in RpoS levels, and this decrease was also suppressed by either codon optimization or blocking RpoS degradation. We suggest that rpoS codon usage leads it to be particularly sensitive to slowed translation, due to either lack of polyamines or hyperproofreading, leading to cotranslational degradation. We dedicate this study to Herb Tabor and his foundational work on polyamines, including the basis for this study.
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Affiliation(s)
- Nadim Majdalani
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA
| | - Manas Chattopadhyay
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Christopher Keller
- Laboratory of Biochemistry and Genetics, NIDDK, NIH, Bethesda, Maryland, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, NCI, Bethesda, Maryland, USA.
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20
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Gerasimov ES, Novozhilova TS, Zimmer SL, Yurchenko V. Kinetoplast Genome of Leishmania spp. Is under Strong Purifying Selection. Trop Med Infect Dis 2023; 8:384. [PMID: 37624322 PMCID: PMC10458658 DOI: 10.3390/tropicalmed8080384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
Instability is an intriguing characteristic of many protist genomes, and trypanosomatids are not an exception in this respect. Some regions of trypanosomatid genomes evolve fast. For instance, the trypanosomatid mitochondrial (kinetoplast) genome consists of fairly conserved maxicircle and minicircle molecules that can, nevertheless, possess high nucleotide substitution rates between closely related strains. Recent experiments have demonstrated that rapid laboratory evolution can result in the non-functionality of multiple genes of kinetoplast genomes due to the accumulation of mutations or loss of critical genomic components. An example of a loss of critical components is the reported loss of entire minicircle classes in Leishmania tarentolae during laboratory cultivation, which results in an inability to generate some correctly encoded genes. In the current work, we estimated the evolutionary rates of mitochondrial and nuclear genome regions of multiple natural Leishmania spp. We analyzed synonymous and non-synonymous substitutions and, rather unexpectedly, found that the coding regions of kinetoplast maxicircles are among the most variable regions of both genomes. In addition, we demonstrate that synonymous substitutions greatly predominate among maxicircle coding regions and that most maxicircle genes show signs of purifying selection. These results imply that maxicircles in natural Leishmania populations remain functional despite their high mutation rate.
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Affiliation(s)
- Evgeny S. Gerasimov
- Department of Molecular Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, 127051 Moscow, Russia
| | - Tatiana S. Novozhilova
- Department of Molecular Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Sara L. Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN 55812, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
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21
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Vihinen M. Nonsynonymous Synonymous Variants Demand for a Paradigm Shift in Genetics. Curr Genomics 2023; 24:18-23. [PMID: 37920730 PMCID: PMC10334700 DOI: 10.2174/1389202924666230417101020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/20/2023] [Accepted: 03/01/2023] [Indexed: 11/04/2023] Open
Abstract
Synonymous (also known as silent) variations are by definition not considered to change the coded protein. Still many variations in this category affect either protein abundance or properties. As this situation is confusing, we have recently introduced systematics for synonymous variations and those that may on the surface look like synonymous, but these may affect the coded protein in various ways. A new category, unsense variation, was introduced to describe variants that do not introduce a stop codon into the variation site, but which lead to different types of changes in the coded protein. Many of these variations lead to mRNA degradation and missing protein. Here, consequences of the systematics are discussed from the perspectives of variation annotation and interpretation, evolutionary calculations, nonsynonymous-to-synonymous substitution rates, phylogenetics and other evolutionary inferences that are based on the principle of (nearly) neutral synonymous variations. It may be necessary to reassess published results. Further, databases for synonymous variations and prediction methods for such variations should consider unsense variations. Thus, there is a need to evaluate and reflect principles of numerous aspects in genetics, ranging from variation naming and classification to evolutionary calculations.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, Lund University, Lund, BMC B13, Sweden
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22
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Giacoletto CJ, Rotter JI, Grody WW, Schiller MR. Synonymous Variants of Uncertain Silence. Int J Mol Sci 2023; 24:10556. [PMID: 37445732 DOI: 10.3390/ijms241310556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Synonymous variants, traditionally regarded as silent mutations due to their lack of impact on protein sequence, structure and function, have been the subject of increasing scrutiny. This commentary explores the emerging evidence challenging the notion of synonymous variants as functionally inert. Analysis of the activity of 70 synonymous variants in the HIV Tat transcription factor revealed that 50% of the variants exhibited significant deviations from wild-type activity. Our analysis supports previous work and raises important questions about the broader impact of non-silent synonymous variants in human genes. Considering the potential functional implications, the authors propose classifying such variants as "synonymous variants of uncertain silence" (sVUS), highlighting the need for cautious interpretation and further investigations in clinical and genetic testing settings.
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Affiliation(s)
- Christopher J Giacoletto
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
- Heligenics Inc., 10530 Discovery Drive, Las Vegas, NV 89135, USA
- School of Life Sciences, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
| | - Jerome I Rotter
- Heligenics Inc., 10530 Discovery Drive, Las Vegas, NV 89135, USA
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Wayne W Grody
- Department of Pathology and Laboratory Medicine, University of California Los Angeles School of Medicine, 10833 Le Conte Ave., 705, Los Angeles, CA 90095, USA
- Department of Pediatrics, University of California Los Angeles School of Medicine, 10833 Le Conte Ave., Los Angeles, CA 90095, USA
- Department of Human Genetics, University of California Los Angeles School of Medicine, 10833 Le Conte Ave., Los Angeles, CA 90095, USA
| | - Martin R Schiller
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
- Heligenics Inc., 10530 Discovery Drive, Las Vegas, NV 89135, USA
- School of Life Sciences, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
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23
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Martínez AA, Lang GI. Identifying Targets of Selection in Laboratory Evolution Experiments. J Mol Evol 2023; 91:345-355. [PMID: 36810618 DOI: 10.1007/s00239-023-10096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023]
Abstract
Adaptive evolution navigates a balance between chance and determinism. The stochastic processes of mutation and drift generate phenotypic variation; however, once mutations reach an appreciable frequency in the population, their fate is governed by the deterministic action of selection, enriching for favorable genotypes and purging the less-favorable ones. The net result is that replicate populations will traverse similar-but not identical-pathways to higher fitness. This parallelism in evolutionary outcomes can be leveraged to identify the genes and pathways under selection. However, distinguishing between beneficial and neutral mutations is challenging because many beneficial mutations will be lost due to drift and clonal interference, and many neutral (and even deleterious) mutations will fix by hitchhiking. Here, we review the best practices that our laboratory uses to identify genetic targets of selection from next-generation sequencing data of evolved yeast populations. The general principles for identifying the mutations driving adaptation will apply more broadly.
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Affiliation(s)
| | - Gregory I Lang
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA.
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Gao S, Jiang Y, Zhou H, Liu Y, Li H, Liu C, Zheng Z. Fine mapping of a Fusarium crown rot resistant locus on chromosome arm 6HL in barley by exploiting near isogenic lines, transcriptome profiling, and a large near isogenic line-derived population. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:137. [PMID: 37233855 DOI: 10.1007/s00122-023-04387-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
KEY MESSAGE This study reported validation and fine mapping of a Fusarium crown rot resistant locus on chromosome arm 6HL in barley using near isogenic lines, transcriptome sequences, and a large near isogenic line-derived population. Fusarium crown rot (FCR), caused by Fusarium pseudograminearum, is a chronic and serious disease affecting cereal production in semi-arid regions globally. The increasing prevalence of this disease in recent years is attributed to the widespread adoption of minimum tillage and stubble retention practices. In the study reported here, we generated eight pairs of near isogenic lines (NILs) targeting a putative QTL (Qcrs.caf-6H) conferring FCR resistance in barley. Assessing the NILs confirmed the large effect of this locus. Aimed to develop markers that can be reliably used in incorporating this resistant allele into breeding programs and identify candidate genes, transcriptomic analyses were conducted against three of the NIL pairs and a large NIL-derived population consisting of 1085 F7 recombinant inbred lines generated. By analyzing the transcriptomic data and the fine mapping population, Qcrs.caf-6H was delineated into an interval of 0.9 cM covering a physical distance of ~ 547 kb. Six markers co-segregating with this locus were developed. Based on differential gene expression and SNP variations between the two isolines among the three NIL pairs, candidate genes underlying the resistance at this locus were detected. These results would improve the efficiency of incorporating the targeted locus into barley breeding programs and facilitate the cloning of causal gene(s) responsible for the resistance.
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Affiliation(s)
- Shang Gao
- CSIRO Agriculture and Food, 306 Carmody Road, St Lucia, QLD, 4067, Australia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, CIMMYT-China Office, 12 Zhongguancun South Street, Beijing, 100081, China
- Nanfan Research Institute, Chinese Academy of Agricultural Sciences, Sanya, 572024, Hainan, China
| | - Yunfeng Jiang
- CSIRO Agriculture and Food, 306 Carmody Road, St Lucia, QLD, 4067, Australia
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, China
| | - Hong Zhou
- CSIRO Agriculture and Food, 306 Carmody Road, St Lucia, QLD, 4067, Australia
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, China
| | - Yaxi Liu
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, China
| | - Huihui Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, CIMMYT-China Office, 12 Zhongguancun South Street, Beijing, 100081, China
- Nanfan Research Institute, Chinese Academy of Agricultural Sciences, Sanya, 572024, Hainan, China
| | - Chunji Liu
- CSIRO Agriculture and Food, 306 Carmody Road, St Lucia, QLD, 4067, Australia.
| | - Zhi Zheng
- CSIRO Agriculture and Food, 306 Carmody Road, St Lucia, QLD, 4067, Australia.
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Yang X, Huo X, Tang Y, Zhao M, Tao Y, Huang J, Ke C. Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:4656-4664. [PMID: 36881553 DOI: 10.1021/acs.jafc.2c07613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
γ-Aminobutyric acid (GABA) is used widely in various fields, such as agriculture, food, pharmaceuticals, and biobased chemicals. Based on glutamate decarboxylase (GadBM4) derived from our previous work, three mutants, GadM4-2, GadM4-8, and GadM4-31, were obtained by integrating enzyme evolution and high-throughput screening methods. The GABA productivity obtained through whole-cell bioconversion using recombinant Escherichia coli cells harboring mutant GadBM4-2 was enhanced by 20.27% compared to that of the original GadBM4. Further introduction of the central regulator GadE of the acid resistance system and the enzymes from the deoxyxylulose-5-phosphate-independent pyridoxal 5'-phosphate biosynthesis pathway resulted in a 24.92% improvement in GABA productivity, reaching 76.70 g/L/h without any cofactor addition with a greater than 99% conversion ratio. Finally, when one-step bioconversion was applied for the whole-cell catalysis in a 5 L bioreactor, the titer of GABA reached 307.5 ± 5.94 g/L with a productivity of 61.49 g/L/h by using crude l-glutamic acid (l-Glu) as the substrate. Thus, the biocatalyst constructed above combined with the whole-cell bioconversion method represents an effective approach for industrial GABA production.
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Affiliation(s)
- Xinwei Yang
- National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, People's Republic of China
| | - Xiaojing Huo
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Yaqian Tang
- National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, People's Republic of China
| | - Mingyue Zhao
- National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, People's Republic of China
| | - Yong Tao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Jianzhong Huang
- National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, People's Republic of China
| | - Chongrong Ke
- National and Local United Engineering Research Center of Industrial Microbiology and Fermentation Technology; College of Life Sciences, Fujian Normal University, Fuzhou 350117, Fujian, People's Republic of China
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Silveiro C, Marques M, Olivença F, Pires D, Mortinho D, Nunes A, Pimentel M, Anes E, Catalão MJ. CRISPRi-mediated characterization of novel anti-tuberculosis targets: Mycobacterial peptidoglycan modifications promote beta-lactam resistance and intracellular survival. Front Cell Infect Microbiol 2023; 13:1089911. [PMID: 37009497 PMCID: PMC10050696 DOI: 10.3389/fcimb.2023.1089911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/03/2023] [Indexed: 03/17/2023] Open
Abstract
The lack of effective therapeutics against emerging multi-drug resistant strains of Mycobacterium tuberculosis (Mtb) prompts the identification of novel anti-tuberculosis targets. The essential nature of the peptidoglycan (PG) layer of the mycobacterial cell wall, which features several distinctive modifications, such as the N-glycolylation of muramic acid and the amidation of D-iso-glutamate, makes it a target of particular interest. To understand their role in susceptibility to beta-lactams and in the modulation of host-pathogen interactions, the genes encoding the enzymes responsible for these PG modifications (namH and murT/gatD, respectively) were silenced in the model organism Mycobacterium smegmatis using CRISPR interference (CRISPRi). Although beta-lactams are not included in TB-therapy, their combination with beta-lactamase inhibitors is a prospective strategy to treat MDR-TB. To uncover synergistic effects between the action of beta-lactams and the depletion of these PG modifications, knockdown mutants were also constructed in strains lacking the major beta-lactamase of M. smegmatis BlaS, PM965 (M. smegmatis ΔblaS1) and PM979 (M. smegmatis ΔblaS1 ΔnamH). The phenotyping assays affirmed the essentiality of the amidation of D-iso-glutamate to the survival of mycobacteria, as opposed to the N-glycolylation of muramic acid. The qRT-PCR assays confirmed the successful repression of the target genes, along with few polar effects and differential knockdown level depending on PAM strength and target site. Both PG modifications were found to contribute to beta-lactam resistance. While the amidation of D-iso-glutamate impacted cefotaxime and isoniazid resistance, the N-glycolylation of muramic acid substantially promoted resistance to the tested beta-lactams. Their simultaneous depletion provoked synergistic reductions in beta-lactam MICs. Moreover, the depletion of these PG modifications promoted a significantly faster bacilli killing by J774 macrophages. Whole-genome sequencing revealed that these PG modifications are highly conserved in a set of 172 clinical strains of Mtb, demonstrating their potential as therapeutic targets against TB. Our results support the development of new therapeutic agents targeting these distinctive mycobacterial PG modifications.
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Affiliation(s)
- Cátia Silveiro
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Mariana Marques
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Francisco Olivença
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - David Pires
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- Universidade Católica Portuguesa, Católica Medical School, Centre for Interdisciplinary Research in Health, Lisbon, Portugal
| | - Diana Mortinho
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Alexandra Nunes
- Genomics and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
- Faculty of Veterinary Medicine, Universidade Lusófona, Lisbon, Portugal
| | - Madalena Pimentel
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Elsa Anes
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Maria João Catalão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
- *Correspondence: Maria João Catalão,
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Li Q, Luo Y, Sha A, Xiao W, Xiong Z, Chen X, He J, Peng L, Zou L. Analysis of synonymous codon usage patterns in mitochondrial genomes of nine Amanita species. Front Microbiol 2023; 14:1134228. [PMID: 36970689 PMCID: PMC10030801 DOI: 10.3389/fmicb.2023.1134228] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 02/14/2023] [Indexed: 03/10/2023] Open
Abstract
IntroductionCodon basis is a common and complex natural phenomenon observed in many kinds of organisms.MethodsIn the present study, we analyzed the base bias of 12 mitochondrial core protein-coding genes (PCGs) shared by nine Amanita species.ResultsThe results showed that the codons of all Amanita species tended to end in A/T, demonstrating the preference of mitochondrial codons of Amanita species for a preference for this codon. In addition, we detected the correlation between codon base composition and the codon adaptation index (CAI), codon bias index (CBI), and frequency of optimal codons (FOP) indices, indicating the influence of base composition on codon bias. The average effective number of codons (ENC) of mitochondrial core PCGs of Amanita is 30.81, which is <35, demonstrating the strong codon preference of mitochondrial core PCGs of Amanita. The neutrality plot analysis and PR2-Bias plot analysis further demonstrated that natural selection plays an important role in Amanita codon bias. In addition, we obtained 5–10 optimal codons (ΔRSCU > 0.08 and RSCU > 1) in nine Amanita species, and GCA and AUU were the most widely used optimal codons. Based on the combined mitochondrial sequence and RSCU value, we deduced the genetic relationship between different Amanita species and found large variations between them.DiscussionThis study promoted the understanding of synonymous codon usage characteristics and evolution of this important fungal group.
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28
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Most synonymous allelic variants in HIV tat are not silent. Genomics 2023; 115:110603. [PMID: 36893872 DOI: 10.1016/j.ygeno.2023.110603] [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: 11/19/2022] [Revised: 02/12/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023]
Abstract
The genetic code has degenerate codons that produce no change in the translated protein sequence and are generally thought to be silent. However, some synonymous variants are clearly not silent. Herein, we questioned the frequency of non-silent synonymous variants. We tested how random synonymous variants in the HIV Tat transcription factor effect transcription of an LTR-GFP reporter. Our model system has the advantage of directly measuring the function of the gene in human cells. Approximately, 67% of synonymous variants in Tat were non-silent, either having reduced activity or were full loss-of-function alleles. Eight mutant codons had higher codon usage than wild type, accompanied by reduced transcriptional activity. These were clustered on a loop in the Tat structure. We conclude that most synonymous Tat variants are not silent in human cells, and 25% are associated with changes in codon usage, likely effecting protein folding.
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Mortazavi M, Torkzadeh-Mahani M, Rahimi M, Maleki M, Lotfi S, Riahi-Madvar A. Effects of synonymous mutations on kinetic properties and structure of firefly luciferase: Molecular dynamics simulation, molecular docking, RNA folding, and experimental study. Int J Biol Macromol 2023; 235:123835. [PMID: 36870640 DOI: 10.1016/j.ijbiomac.2023.123835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023]
Abstract
Although synonymous mutations have long been thought to lack striking results, a growing body of research shows these mutations have highly variable effects. In this study, the impact of synonymous mutations in the development of thermostable luciferase was investigated using a combination of experimental and theoretical approaches. Using bioinformatics analysis, the codon usage features in the Lampyridae family's luciferases were studied and four synonymous mutations of Arg in luciferase were created. An exciting result was that the analysis of kinetic parameters showed a slight increase in the thermal stability of the mutant luciferase. AutoDock Vina, %MinMax algorithm, and UNAFold Server were used to perform molecular docking, folding rate, and RNA folding, respectively. Here, it was assumed that in the region (Arg337) with a moderate propensity for coil, synonymous mutation altered the rate of translation, which in turn may lead to a slight change in the structure of the enzyme. According to the molecular dynamics simulation data, local minor global flexibility is observed in the context of the protein conformation. A plausible explanation is that this flexibility may strengthen hydrophobic interactions due to its sensitivity to a molecular collision. Accordingly, thermostability originated mainly from hydrophobic interaction.
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Affiliation(s)
- Mojtaba Mortazavi
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran.
| | - Masoud Torkzadeh-Mahani
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran
| | - Mehdi Rahimi
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran
| | - Mahmood Maleki
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran
| | - Safa Lotfi
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran
| | - Ali Riahi-Madvar
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, Kosar University of Bojnord, Bojnord, Iran
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Densi A, Iyer RS, Bhat PJ. Synonymous and Nonsynonymous Substitutions in Dictyostelium discoideum Ammonium Transporter amtA Are Necessary for Functional Complementation in Saccharomyces cerevisiae. Microbiol Spectr 2023; 11:e0384722. [PMID: 36840598 PMCID: PMC10100761 DOI: 10.1128/spectrum.03847-22] [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: 09/21/2022] [Accepted: 01/24/2023] [Indexed: 02/24/2023] Open
Abstract
Ammonium transporters are present in all three domains of life. They have undergone extensive horizontal gene transfer (HGT), gene duplication, and functional diversification and therefore offer an excellent paradigm to study protein evolution. We attempted to complement a mep1Δmep2Δmep3Δ strain of Saccharomyces cerevisiae (triple-deletion strain), which otherwise cannot grow on ammonium as a sole nitrogen source at concentrations of <3 mM, with amtA of Dictyostelium discoideum, an orthologue of S. cerevisiae MEP2. We observed that amtA did not complement the triple-deletion strain of S. cerevisiae for growth on low-ammonium medium. We isolated two mutant derivatives of amtA (amtA M1 and amtA M2) from a PCR-generated mutant plasmid library that complemented the triple-deletion strain of S. cerevisiae. amtA M1 bears three nonsynonymous and two synonymous substitutions, which are necessary for its functionality. amtA M2 bears two nonsynonymous substitutions and one synonymous substitution, all of which are necessary for functionality. Interestingly, AmtA M1 transports ammonium but does not confer methylamine toxicity, while AmtA M2 transports ammonium and confers methylamine toxicity, demonstrating functional diversification. Preliminary biochemical analyses indicated that the mutants differ in their conformations as well as their mechanisms of ammonium transport. These intriguing results clearly point out that protein evolution cannot be fathomed by studying nonsynonymous and synonymous substitutions in isolation. The above-described observations have significant implications for various facets of biological processes and are discussed in detail. IMPORTANCE Functional diversification following gene duplication is one of the major driving forces of protein evolution. While the role of nonsynonymous substitutions in the functional diversification of proteins is well recognized, knowledge of the role of synonymous substitutions in protein evolution is in its infancy. Using functional complementation, we isolated two functional alleles of the D. discoideum ammonium transporter gene (amtA), which otherwise does not function in S. cerevisiae as an ammonium transporters. One of them is an ammonium transporter, while the other is an ammonium transporter that also confers methylammonium (ammonium analogue) toxicity, suggesting functional diversification. Surprisingly, both alleles require a combination of synonymous and nonsynonymous substitutions for their functionality. These results bring out a hitherto-unknown pathway of protein evolution and pave the way for not only understanding protein evolution but also interpreting single nucleotide polymorphisms (SNPs).
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Affiliation(s)
- Asha Densi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Revathi S. Iyer
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Paike Jayadeva Bhat
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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Abstract
Phylogenetic analysis of monkeypox virus genomes showed statistically significant divergence and nascent subclades during the 2022 mpox outbreak. Frequency of G>A/C>T transitions has increased in recent years, probably resulting from apolipoprotein B mRNA editing enzyme catalytic polypeptide 3G (APOBEC3) deaminase editing. This microevolutionary pattern most likely reflects community spread of the virus and adaptation to humans.
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32
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Wu P, Xiao W, Luo Y, Xiong Z, Chen X, He J, Sha A, Gui M, Li Q. Comprehensive analysis of codon bias in 13 Ganoderma mitochondrial genomes. Front Microbiol 2023; 14:1170790. [PMID: 37213503 PMCID: PMC10192751 DOI: 10.3389/fmicb.2023.1170790] [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: 02/21/2023] [Accepted: 04/12/2023] [Indexed: 05/23/2023] Open
Abstract
Introduction Codon usage bias is a prevalent phenomenon observed across various species and genes. However, the specific attributes of codon usage in the mitochondrial genome of Ganoderma species remain unknown. Methods In this study, we investigated the codon bias of 12 mitochondrial core protein-coding genes (PCGs) in 9 Ganoderma species, including 13 Ganoderma strains. Results The codons of all Ganoderma strains showed a preference for ending in A/T. Additionally, correlations between codon base composition and the codon adaptation index (CAI), codon bias index (CBI) and frequency of optimal codons (FOP) were identified, demonstrating the impact of base composition on codon bias. Various base bias indicators were found to vary between or within Ganoderma strains, including GC3s, the CAI, the CBI, and the FOP. The results also revealed that the mitochondrial core PCGs of Ganoderma have an average effective number of codons (ENC) lower than 35, indicating strong bias toward certain codons. Evidence from neutrality plot and PR2-bias plot analysis indicates that natural selection is a major factor affecting codon bias in Ganoderma. Additionally, 11 to 22 optimal codons (ΔRSCU>0.08 and RSCU>1) were identified in 13 Ganoderma strains, with GCA, AUC, and UUC being the most widely used optimal codons in Ganoderma. By analyzing the combined mitochondrial sequences and relative synonymous codon usage (RSCU) values, the genetic relationships between or within Ganoderma strains were determined, indicating variations between them. Nevertheless, RSCU-based analysis illustrated the intra- and interspecies relationships of certain Ganoderma species. Discussion This study deepens our insight into the synonymous codon usage characteristics, genetics, and evolution of this important fungal group.
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Affiliation(s)
- Peng Wu
- Yunnan Plateau Characteristic Agricultural Industry Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Wenqi Xiao
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Yingyong Luo
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Zhuang Xiong
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Xiaodie Chen
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Jing He
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Ajia Sha
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
| | - Mingying Gui
- Yunnan Plateau Characteristic Agricultural Industry Research Institute, Yunnan Agricultural University, Kunming, Yunnan, China
- *Correspondence: Mingying Gui,
| | - Qiang Li
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Engineering and Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, Chengdu, Sichuan, China
- Qiang Li,
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Joyce LR, Youngblom MA, Cormaty H, Gartstein E, Barber KE, Akins RL, Pepperell CS, Palmer KL. Comparative Genomics of Streptococcus oralis Identifies Large Scale Homologous Recombination and a Genetic Variant Associated with Infection. mSphere 2022; 7:e0050922. [PMID: 36321824 PMCID: PMC9769543 DOI: 10.1128/msphere.00509-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 11/07/2022] Open
Abstract
The viridans group streptococci (VGS) are a large consortium of commensal streptococci that colonize the human body. Many species within this group are opportunistic pathogens causing bacteremia and infective endocarditis (IE), yet little is known about why some strains cause invasive disease. Identification of virulence determinants is complicated by the difficulty of distinguishing between the closely related species of this group. Here, we analyzed genomic data from VGS that were isolated from blood cultures in patients with invasive infections and oral swabs of healthy volunteers and then determined the best-performing methods for species identification. Using whole-genome sequence data, we characterized the population structure of a diverse sample of Streptococcus oralis isolates and found evidence of frequent recombination. We used multiple genome-wide association study tools to identify candidate determinants of invasiveness. These tools gave consistent results, leading to the discovery of a single synonymous single nucleotide polymorphism (SNP) that was significantly associated with invasiveness. This SNP was within a previously undescribed gene that was conserved across the majority of VGS species. Using the growth in the presence of human serum and a simulated infective endocarditis vegetation model, we were unable to identify a phenotype for the enriched allele in laboratory assays, suggesting a phenotype may be specific to natural infection. These data highlighted the power of analyzing natural populations for gaining insight into pathogenicity, particularly for organisms with complex population structures like the VGS. IMPORTANCE The viridians group streptococci (VGS) are a large collection of closely related commensal streptococci, with many being opportunistic pathogens causing invasive diseases, such as bacteremia and infective endocarditis. Little is known about virulence determinants in these species, and there is a distinct lack of genomic information available for the VGS. In this study, we collected VGS isolates from invasive infections and healthy volunteers and performed whole-genome sequencing for a suite of downstream analyses. We focused on a diverse sample of Streptococcus oralis genomes and identified high rates of recombination in the population as well as a single genome variant highly enriched in invasive isolates. The variant lies within a previously uncharacterized gene, nrdM, which shared homology with the anaerobic ribonucleoside triphosphate reductase, nrdD, and was highly conserved among VGS. This work increased our knowledge of VGS genomics and indicated that differences in virulence potential among S. oralis isolates were, at least in part, genetically determined.
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Affiliation(s)
- Luke R. Joyce
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Madison A. Youngblom
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Harshini Cormaty
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Evelyn Gartstein
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, USA
| | - Katie E. Barber
- Department of Pharmacy Practice, University of Mississippi School of Pharmacy, University of Mississippi, Jackson, Mississippi, USA
| | | | - Caitlin S. Pepperell
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine (Infectious Diseases), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kelli L. Palmer
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, USA
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Chandra S, Gupta K, Khare S, Kohli P, Asok A, Mohan SV, Gowda H, Varadarajan R. The High Mutational Sensitivity of ccdA Antitoxin Is Linked to Codon Optimality. Mol Biol Evol 2022; 39:6693774. [PMID: 36069948 PMCID: PMC9555053 DOI: 10.1093/molbev/msac187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Deep mutational scanning studies suggest that synonymous mutations are typically silent and that most exposed, nonactive-site residues are tolerant to mutations. Here, we show that the ccdA antitoxin component of the Escherichia coli ccdAB toxin-antitoxin system is unusually sensitive to mutations when studied in the operonic context. A large fraction (∼80%) of single-codon mutations, including many synonymous mutations in the ccdA gene shows inactive phenotype, but they retain native-like binding affinity towards cognate toxin, CcdB. Therefore, the observed phenotypic effects are largely not due to alterations in protein structure/stability, consistent with a large region of CcdA being intrinsically disordered. E. coli codon preference and strength of ribosome-binding associated with translation of downstream ccdB gene are found to be major contributors of the observed ccdA mutant phenotypes. In select cases, proteomics studies reveal altered ratios of CcdA:CcdB protein levels in vivo, suggesting that the ccdA mutations likely alter relative translation efficiencies of the two genes in the operon. We extend these results by studying single-site synonymous mutations that lead to loss of function phenotypes in the relBE operon upon introduction of rarer codons. Thus, in their operonic context, genes are likely to be more sensitive to both synonymous and nonsynonymous point mutations than inferred previously.
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Affiliation(s)
| | | | - Shruti Khare
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Pehu Kohli
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Aparna Asok
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | | | - Harsha Gowda
- Institute of Bioinformatics, Bangalore 560100, India
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35
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Growth fitness, heme uptake and genomic variants in mutants of oxygen-tolerant Lacticaseibacillus casei and Lactiplantibacillus plantarum strains. Microbiol Res 2022; 262:127096. [DOI: 10.1016/j.micres.2022.127096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 06/04/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022]
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36
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Schick A, Shewaramani S, Kassen R. Genomics of diversification of Pseudomonas aeruginosa in cystic fibrosis lung-like conditions. Genome Biol Evol 2022; 14:6602282. [PMID: 35660861 PMCID: PMC9168666 DOI: 10.1093/gbe/evac074] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 04/22/2022] [Accepted: 05/12/2022] [Indexed: 12/03/2022] Open
Abstract
Pseudomonas aeruginosa is among the most problematic opportunistic pathogens for adults with cystic fibrosis (CF), causing repeated and resilient infections in the lung and surrounding airways. Evidence suggests that long-term infections are associated with diversification into specialized types but the underlying cause of that diversification and the effect it has on the persistence of infections remains poorly understood. Here, we use evolve-and-resequence experiments to investigate the genetic changes accompanying rapid, de novo phenotypic diversification in lab environments designed to mimic two aspects of human lung ecology: spatial structure and complex nutritional content. After ∼220 generations of evolution, we find extensive genetic variation present in all environments, including those that most closely resemble the CF lung. We use the abundance and frequency of nonsynonymous and synonymous mutations to estimate the ratio of mutations that are selectively neutral (hitchhikers) to those that are under positive selection (drivers). A significantly lower proportion of driver mutations in spatially structured populations suggests that reduced dispersal generates subpopulations with reduced effective population size, decreasing the supply of beneficial mutations and causing more divergent evolutionary trajectories. In addition, we find mutations in a handful of genes typically associated with chronic infection in the CF lung, including one gene associated with antibiotic resistance. This demonstrates that many of the genetic changes considered to be hallmarks of CF lung adaptation can arise as a result of adaptation to a novel environment and do not necessarily require antimicrobial treatment, immune system suppression, or competition from other microbial species to occur.
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Affiliation(s)
- Alana Schick
- Biology Department and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Sonal Shewaramani
- Biology Department and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Rees Kassen
- Biology Department and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
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37
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Erić P, Patenković A, Erić K, Tanasković M, Davidović S, Rakić M, Savić Veselinović M, Stamenković-Radak M, Jelić M. Temperature-Specific and Sex-Specific Fitness Effects of Sympatric Mitochondrial and Mito-Nuclear Variation in Drosophila obscura. INSECTS 2022; 13:insects13020139. [PMID: 35206713 PMCID: PMC8880146 DOI: 10.3390/insects13020139] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/20/2022] [Accepted: 01/22/2022] [Indexed: 12/28/2022]
Abstract
Simple Summary Does variation in the mitochondrial DNA sequence influence the survival and reproduction of an individual? What is the purpose of genetic variation of the mitochondrial DNA between individuals from the same population? As a simple laboratory model, Drosophila species can give us the answer to this question. Creating experimental lines with different combinations of mitochondrial and nuclear genomic DNA and testing how successful these lines were in surviving in different experimental set-ups enables us to deduce the effect that both genomes have on fitness. This study on D. obscura experimentally validates theoretical models that explain the persistence of mitochondrial DNA variation within populations. Our results shed light on the various mechanisms that maintain this type of variation. Finally, by conducting the experiments on two experimental temperatures, we have shown that environmental variations can support mitochondrial DNA variation within populations. Abstract The adaptive significance of sympatric mitochondrial (mtDNA) variation and the role of selective mechanisms that maintain it are debated to this day. Isofemale lines of Drosophila obscura collected from four populations were backcrossed within populations to construct experimental lines, with all combinations of mtDNA Cyt b haplotypes and nuclear genetic backgrounds (nuDNA). Individuals of both sexes from these lines were then subjected to four fitness assays (desiccation resistance, developmental time, egg-to-adult viability and sex ratio) on two experimental temperatures to examine the role of temperature fluctuations and sex-specific selection, as well as the part that interactions between the two genomes play in shaping mtDNA variation. The results varied across populations and fitness components. In the majority of comparisons, they show that sympatric mitochondrial variants affect fitness. However, their effect should be examined in light of interactions with nuDNA, as mito-nuclear genotype was even more influential on fitness across all components. We found both sex-specific and temperature-specific differences in mitochondrial and mito-nuclear genotype ranks in all fitness components. The effect of temperature-specific selection was found to be more prominent, especially in desiccation resistance. From the results of different components tested, we can also infer that temperature-specific mito-nuclear interactions rather than sex-specific selection on mito-nuclear genotypes have a more substantial role in preserving mtDNA variation in this model species.
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Affiliation(s)
- Pavle Erić
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
- Correspondence: ; Tel.: +381-112-078-334
| | - Aleksandra Patenković
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
| | - Katarina Erić
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
| | - Marija Tanasković
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
| | - Slobodan Davidović
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
| | - Mina Rakić
- Department of Genetics of Populations and Ecogenotoxicology, Institute for Biological Research “Siniša Stanković”–National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia; (A.P.); (K.E.); (M.T.); (S.D.); (M.R.)
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (M.S.V.); (M.S.-R.); (M.J.)
| | - Marija Savić Veselinović
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (M.S.V.); (M.S.-R.); (M.J.)
| | - Marina Stamenković-Radak
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (M.S.V.); (M.S.-R.); (M.J.)
| | - Mihailo Jelić
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (M.S.V.); (M.S.-R.); (M.J.)
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38
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McGrath C. Synonymous but Not Equal: A Special Section and Virtual Issue on Phenotypic Effects of Synonymous Mutations. Genome Biol Evol 2021. [PMCID: PMC8410135 DOI: 10.1093/gbe/evab186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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39
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Vlková M, Morampalli BR, Silander OK. Efficiency of the synthetic self-splicing RiboJ ribozyme is robust to cis- and trans-changes in genetic background. Microbiologyopen 2021; 10:e1232. [PMID: 34459545 PMCID: PMC8383906 DOI: 10.1002/mbo3.1232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 01/08/2023] Open
Abstract
The expanding knowledge of the variety of synthetic genetic elements has enabled the construction of new and more efficient genetic circuits and yielded novel insights into molecular mechanisms. However, context dependence, in which interactions between cis- or trans-genetic elements affect the behavior of these elements, can reduce their general applicability or predictability. Genetic insulators, which mitigate unintended context-dependent cis-interactions, have been used to address this issue. One of the most commonly used genetic insulators is a self-splicing ribozyme called RiboJ, which can be used to decouple upstream 5' UTR in mRNA from downstream sequences (e.g., open reading frames). Despite its general use as an insulator, there has been no systematic study quantifying the efficiency of RiboJ splicing or whether this autocatalytic activity is robust to trans- and cis-genetic context. Here, we determine the robustness of RiboJ splicing in the genetic context of six widely divergent E. coli strains. We also check for possible cis-effects by assessing two SNP versions close to the catalytic site of RiboJ. We show that mRNA molecules containing RiboJ are rapidly spliced even during rapid exponential growth and high levels of gene expression, with a mean efficiency of 98%. We also show that neither the cis- nor trans-genetic context has a significant impact on RiboJ activity, suggesting this element is robust to both cis- and trans-genetic changes.
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Affiliation(s)
- Markéta Vlková
- School of Natural and Computational SciencesMassey UniversityAucklandNew Zealand
| | | | - Olin K. Silander
- School of Natural and Computational SciencesMassey UniversityAucklandNew Zealand
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