scholarly journals Genome Stability in Engineered Strains of the Extremely Thermophilic Lignocellulose-Degrading Bacterium Caldicellulosiruptor bescii

2017 ◽  
Vol 83 (14) ◽  
Author(s):  
Amanda M. Williams-Rhaesa ◽  
Farris L. Poole ◽  
Jessica T. Dinsmore ◽  
Gina L. Lipscomb ◽  
Gabriel M. Rubinstein ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Single Nucleotide Polymorphisms ◽  
Genetic Background ◽  
Genome Stability ◽  
Plant Biomass ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Content Type ◽  
Targeted Deletion ◽  
Caldicellulosiruptor Bescii

ABSTRACT Caldicellulosiruptor bescii is the most thermophilic cellulose degrader known and is of great interest because of its ability to degrade nonpretreated plant biomass. For biotechnological applications, an efficient genetic system is required to engineer it to convert plant biomass into desired products. To date, two different genetically tractable lineages of C. bescii strains have been generated. The first (JWCB005) is based on a random deletion within the pyrimidine biosynthesis genes pyrFA, and the second (MACB1018) is based on the targeted deletion of pyrE, making use of a kanamycin resistance marker. Importantly, an active insertion element, ISCbe4, was discovered in C. bescii when it disrupted the gene for lactate dehydrogenase (ldh) in strain JWCB018, constructed in the JWCB005 background. Additional instances of ISCbe4 movement in other strains of this lineage are presented herein. These observations raise concerns about the genetic stability of such strains and their use as metabolic engineering platforms. In order to investigate genome stability in engineered strains of C. bescii from the two lineages, genome sequencing and Southern blot analyses were performed. The evidence presented shows a dramatic increase in the number of single nucleotide polymorphisms, insertions/deletions, and ISCbe4 elements within the genome of JWCB005, leading to massive genome rearrangements in its daughter strain, JWCB018. Such dramatic effects were not evident in the newer MACB1018 lineage, indicating that JWCB005 and its daughter strains are not suitable for metabolic engineering purposes in C. bescii. Furthermore, a facile approach for assessing genomic stability in C. bescii has been established. IMPORTANCE Caldicellulosiruptor bescii is a cellulolytic extremely thermophilic bacterium of great interest for metabolic engineering efforts geared toward lignocellulosic biofuel and bio-based chemical production. Genetic technology in C. bescii has led to the development of two uracil auxotrophic genetic background strains for metabolic engineering. We show that strains derived from the genetic background containing a random deletion in uracil biosynthesis genes (pyrFA) have a dramatic increase in the number of single nucleotide polymorphisms, insertions/deletions, and ISCbe4 insertion elements in their genomes compared to the wild type. At least one daughter strain of this lineage also contains large-scale genome rearrangements that are flanked by these ISCbe4 elements. In contrast, strains developed from the second background strain developed using a targeted deletion strategy of the uracil biosynthetic gene pyrE have a stable genome structure, making them preferable for future metabolic engineering studies.

scholarly journals Causal Role of Single Nucleotide Polymorphisms within themprFGene of Staphylococcus aureus in Daptomycin Resistance

2013 ◽  
Vol 57 (11) ◽  
pp. 5658-5664 ◽  
Author(s):  
Soo-Jin Yang ◽  
Nagendra N. Mishra ◽  
Aileen Rubio ◽  
Arnold S. Bayer
Keyword(s):  
Staphylococcus Aureus ◽  
Single Nucleotide Polymorphisms ◽  
Point Mutations ◽  
Nucleotide Polymorphisms ◽  
Wild Type ◽  
Single Nucleotide ◽  
Content Type ◽  
Reading Frame ◽  
A Charge

ABSTRACTSingle nucleotide polymorphisms (SNPs) within themprFopen reading frame (ORF) have been commonly observed in daptomycin-resistant (DAPr)Staphylococcus aureusstrains. Such SNPs are usually associated with a gain-in-function phenotype, in terms of either increased synthesis or enhanced translocation (flipping) of lysyl-phosphatidylglycerol (L-PG). However, it is unclear if suchmprFSNPs are causal in DAPrstrains or are merely a biomarker for this phenotype. In this study, we used an isogenic set ofS. aureusstrains: (i) Newman, (ii) its isogenic ΔmprFmutant, and (iii) several intransplasmid complementation constructs, expressing either a wild-type or point-mutated form of themprFORF cloned from two isogenic DAP-susceptible (DAPs)-DAPrstrain pairs (616-701 and MRSA11/11-REF2145). Complementation of the ΔmprFstrain with singly point-mutatedmprFgenes (mprFS295LormprFT345A) revealed that (i) individual and distinct point mutations within themprFORF can recapitulate phenotypes observed in donor strains (i.e., changes in DAP MICs, positive surface charge, and cell membrane phospholipid profiles) and (ii) these gain-in-function SNPs (i.e., enhanced L-PG synthesis) likely promote reduced DAP binding toS. aureusby a charge repulsion mechanism. Thus, for these two DAPrstrains, the definedmprFSNPs appear to be causally related to this phenotype.

scholarly journals Using Mycobacterium tuberculosis Single-Nucleotide Polymorphisms To Predict Fluoroquinolone Treatment Response

2019 ◽  
Vol 63 (7) ◽  
Author(s):  
Marva Seifert ◽  
Edmund Capparelli ◽  
Donald G. Catanzaro ◽  
Timothy C. Rodwell
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Single Nucleotide Polymorphisms ◽  
Specific Resistance ◽  
Therapeutic Targets ◽  
World Health ◽  
Population Pharmacokinetic ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Content Type ◽  
Level Increase

ABSTRACT Clinical phenotypic fluoroquinolone susceptibility testing of Mycobacterium tuberculosis is currently based on M. tuberculosis growth at a single critical concentration, which provides limited information for a nuanced clinical response. We propose using specific resistance-conferring M. tuberculosis mutations in gyrA together with population pharmacokinetic and pharmacodynamic modeling as a novel tool to better inform fluoroquinolone treatment decisions. We sequenced the gyrA resistance-determining region of 138 clinical M. tuberculosis isolates collected from India, Moldova, Philippines, and South Africa and then determined each strain’s MIC against ofloxacin, moxifloxacin, levofloxacin, and gatifloxacin. Strains with specific gyrA single-nucleotide polymorphisms (SNPs) were grouped into high or low drug-specific resistance categories based on their empirically measured MICs. Published population pharmacokinetic models were then used to explore the pharmacokinetics and pharmacodynamics of each fluoroquinolone relative to the empirical MIC distribution for each resistance category to make predictions about the likelihood of patients achieving defined therapeutic targets. In patients infected with M. tuberculosis isolates containing SNPs associated with a fluoroquinolone-specific low-level increase in MIC, models suggest increased fluoroquinolone dosing improved the probability of achieving therapeutic targets for gatifloxacin and moxifloxacin but not for levofloxacin and ofloxacin. In contrast, among patients with isolates harboring SNPs associated with a high-level increase in MIC, increased dosing of levofloxacin, moxifloxacin, gatifloxacin, or ofloxacin did not meaningfully improve the probability of therapeutic target attainment. We demonstrated that quantifiable fluoroquinolone drug resistance phenotypes could be predicted from rapidly detectable gyrA SNPs and used to support dosing decisions based on the likelihood of patients reaching therapeutic targets. Our findings provide further supporting evidence for the moxifloxacin clinical breakpoint recently established by the World Health Organization.

scholarly journals Quantitative Analysis of Single-Nucleotide Polymorphism for Rapid Detection of TR34/L98H- and TR46/Y121F/T289A-Positive Aspergillus fumigatus Isolates Obtained from Patients in Iran from 2010 to 2014

2015 ◽  
Vol 60 (1) ◽  
pp. 387-392 ◽  
Author(s):  
Faezeh Mohammadi ◽  
Seyed Jamal Hashemi ◽  
Jan Zoll ◽  
Willem J. G. Melchers ◽  
Haleh Rafati ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Quantitative Analysis ◽  
Single Nucleotide Polymorphisms ◽  
Aspergillus Fumigatus ◽  
Tandem Repeat ◽  
Promoter Region ◽  
Nucleotide Polymorphisms ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Content Type

ABSTRACTWe employed an endpoint genotyping method to update the prevalence rate of positivity for the TR34/L98H mutation (a 34-bp tandem repeat mutation in the promoter region of thecyp51Agene in combination with a substitution at codon L98) and the TR46/Y121F/T289A mutation (a 46-bp tandem repeat mutation in the promoter region of thecyp51Agene in combination with substitutions at codons Y121 and T289) among clinicalAspergillus fumigatusisolates obtained from different regions of Iran over a recent 5-year period (2010 to 2014). The antifungal activities of itraconazole, voriconazole, and posaconazole against 172 clinicalA. fumigatusisolates were investigated using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. For the isolates with an azole resistance phenotype, thecyp51Agene and its promoter were amplified and sequenced. In addition, using a LightCycler 480 real-time PCR system, a novel endpoint genotyping analysis method targeting single-nucleotide polymorphisms was evaluated to detect the L98H and Y121F mutations in thecyp51Agene of all isolates. Of the 172A. fumigatusisolates tested, the MIC values of itraconazole (≥16 mg/liter) and voriconazole (>4 mg/liter) were high for 6 (3.5%). Quantitative analysis of single-nucleotide polymorphisms showed the TR34/L98H mutation in thecyp51Agenes of six isolates. No isolates harboring the TR46/Y121F/T289A mutation were detected. DNA sequencing of thecyp51Agene confirmed the results of the novel endpoint genotyping method. By microsatellite typing, all of the azole-resistant isolates had genotypes different from those previously recovered from Iran and from the Dutch TR34/L98H controls. In conclusion, there was not a significant increase in the prevalence of azole-resistantA. fumigatusisolates harboring the TR34/L98H resistance mechanism among isolates recovered over a recent 5-year period (2010 to 2014) in Iran. A quantitative assay detecting a single-nucleotide polymorphism in thecyp51Agene ofA. fumigatusis a reliable tool for the rapid screening and monitoring of TR34/L98H- and TR46/Y121F/T289A-positive isolates and can easily be incorporated into clinical mycology algorithms.

scholarly journals Genetic diversity and genetic origin of Lanping black-boned sheep investigated by genome-wide single-nucleotide polymorphisms (SNPs)

2020 ◽  
Vol 63 (1) ◽  
pp. 193-201
Author(s):  
Heli Xiong ◽  
Xiaoming He ◽  
Jing Li ◽  
Xingneng Liu ◽  
Chaochao Peng ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Single Nucleotide Polymorphisms ◽  
Structure Analysis ◽  
Genetic Background ◽  
Nucleotide Polymorphisms ◽  
Genetic Origin ◽  
Single Nucleotide ◽  
Sheep Breeds ◽  
Genome Wide ◽  
Nj Tree

Abstract. Lanping black-boned sheep was first discovered in the 1950s in Lanping county of China and characterized by black pigmentation on skin and internal organs. Due to the novel and unique trait, the genetic background of Lanping black-boned sheep is of great interest. Here, we genotyped genome-wide SNPs (single nucleotide polymorphisms) of Lanping black-boned sheep and Lanping normal sheep using Illumina OvineSNP50 BeadChip to investigate the genetic diversity and genetic origin of Lanping black-boned sheep. We also downloaded a subset SNP dataset of two Tibet-lineage sheep breeds and four other sheep breeds from the International Sheep Genomics Consortium (ISGC) as a reference for interpreting. Lanping black-boned sheep had a lower genetic diversity level when compared to seven other sheep breeds. Principal component analysis (PCA) showed that Lanping black-boned sheep and Lanping normal sheep were clustered into the Asian group, but there was no clear separation between the two breeds. Structure analysis demonstrated a high ancestry coefficient in Lanping black-boned sheep and Lanping normal sheep. However, the two populations were separated into two distinct branches in a neighbor-joining (NJ) tree. We further evaluated the genetic divergence using population FST, which showed that the genetic differentiation that existed between Lanping black-boned sheep and Lanping normal sheep was higher than that between Tibet sheep and Changthangi sheep, which revealed that Lanping black-boned sheep is a different breed from Lanping normal sheep on the genetic level. In addition, structure analysis and NJ tree showed that Lanping black-boned sheep had a relatively close relation with Tibet sheep. The results reported herein are a first step toward understanding the genetic background of Lanping black-boned sheep, and it will provide informative knowledge on the unique genetic resource conservation and mechanism of novel breed formation.

scholarly journals Three Substrains of the CyanobacteriumAnabaenasp. Strain PCC 7120 Display Divergence in Genomic Sequences andhetCFunction

2018 ◽  
Vol 200 (13) ◽  
Author(s):  
Yali Wang ◽  
Yuan Gao ◽  
Chao Li ◽  
Hong Gao ◽  
Cheng-Cai Zhang ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Single Nucleotide Polymorphisms ◽  
Fluorescent Protein ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Content Type ◽  
Gfp Fluorescence ◽  
Green Fluorescent ◽  
Pcc 7120 ◽  
Heterocyst Development

ABSTRACTAnabaenasp. strain PCC 7120 is a model strain for molecular studies of cell differentiation and patterning in heterocyst-forming cyanobacteria. Subtle differences in heterocyst development have been noticed in different laboratories working on the same organism. In this study, 360 mutations, including single nucleotide polymorphisms (SNPs), small insertion/deletions (indels; 1 to 3 bp), fragment deletions, and transpositions, were identified in the genomes of three substrains. Heterogeneous/heterozygous bases were also identified due to the polyploidy nature of the genome and the multicellular morphology but could be completely segregated when plated after filament fragmentation by sonication.hetCis a gene upregulated in developing cells during heterocyst formation inAnabaenasp. strain PCC 7120 and found in approximately half of other heterocyst-forming cyanobacteria. Inactivation ofhetCin 3 substrains ofAnabaenasp. PCC 7120 led to different phenotypes: the formation of heterocysts, differentiating cells that keep dividing, or the presence of both heterocysts and dividing differentiating cells. The expression of PhetZ-gfpin thesehetCmutants also showed different patterns of green fluorescent protein (GFP) fluorescence. Thus, the function ofhetCis influenced by the genomic background and epistasis and constitutes an example of evolution under way.IMPORTANCEOur knowledge about the molecular genetics of heterocyst formation, an important cell differentiation process for global N2fixation, is mostly based on studies withAnabaenasp. strain PCC 7120. Here, we show that rapid microevolution is under way in this strain, leading to phenotypic variations for certain genes related to heterocyst development, such ashetC. This study provides an example for ongoing microevolution, marked by multiple heterogeneous/heterozygous single nucleotide polymorphisms (SNPs), in a multicellular multicopy-genome microorganism.

scholarly journals Genome-Wide Identification of Host-Segregating Single-Nucleotide Polymorphisms for Source Attribution of Clinical Campylobacter coli Isolates

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Quentin Jehanne ◽  
Ben Pascoe ◽  
Lucie Bénéjat ◽  
Astrid Ducournau ◽  
Alice Buissonnière ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Common Species ◽  
Frequency Variation ◽  
Common Source ◽  
Campylobacter Coli ◽  
Nucleotide Polymorphisms ◽  
Source Attribution ◽  
Single Nucleotide ◽  
Content Type ◽  
Genome Wide

ABSTRACT Campylobacter is among the most common causes of gastroenteritis worldwide. Campylobacter jejuni and Campylobacter coli are the most common species causing human disease. DNA sequence-based methods for strain characterization have focused largely on C. jejuni, responsible for 80 to 90% of infections, meaning that C. coli epidemiology has lagged behind. Here, we have analyzed the genome of 450 C. coli isolates to determine genetic markers that can discriminate isolates sampled from 3 major reservoir hosts (chickens, cattle, and pigs). These markers then were applied to identify the source of infection of 147 C. coli strains from French clinical cases. Using STRUCTURE software, 259 potential host-segregating markers were revealed by probabilistic characterization of single-nucleotide polymorphism (SNP) frequency variation in strain collections from three different hosts. These SNPs were found in 41 genes or intergenic regions, mostly coding for proteins involved in motility and membrane functions. Source attribution of clinical isolates based on the differential presence of these markers confirmed chickens as the most common source of C. coli infection in France. IMPORTANCE Genome-wide and source attribution studies based on Campylobacter species have shown their importance for the understanding of foodborne infections. Although the use of multilocus sequence typing based on 7 genes from C. jejuni is a powerful method to structure populations, when applied to C. coli, results have not clearly demonstrated its robustness. Therefore, we aim to provide more accurate data based on the identification of single-nucleotide polymorphisms. Results from this study reveal an important number of host-segregating SNPs, found in proteins involved in motility, membrane functions, or DNA repair systems. These findings offer new, interesting opportunities for further study of C. coli adaptation to its environment. Additionally, the results demonstrate that poultry is potentially the main reservoir of C. coli in France.

scholarly journals Evolution and Single-Nucleotide Polymorphisms in Methicillin-Resistant Staphylococcus aureus Strains with Reduced Susceptibility to Vancomycin and Daptomycin, Based on Determination of the Complete Genome

2015 ◽  
Vol 59 (6) ◽  
pp. 3585-3587 ◽  
Author(s):  
Tetsuo Yamaguchi ◽  
Shingo Suzuki ◽  
Sakiko Okamura ◽  
Yuri Miura ◽  
Ayaka Tsukimori ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Single Nucleotide Polymorphisms ◽  
Complete Genome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Methicillin Resistant ◽  
Content Type ◽  
Rifampin Resistance ◽  
Generation Sequencing

ABSTRACTWe obtained a series of methicillin-resistantStaphylococcus aureusisolates, including both daptomycin-susceptible strain TD1 and daptomycin-resistant strain TD4, from a patient. We determined the complete genome sequences of TD1 and TD4 using next-generation sequencing, and only four single-nucleotide polymorphisms (SNPs) were identified, one each incapB(E58K),rpoB(H481Y),lytN(I16V), andmprF(V351E). We determined that these four SNPs were sufficient to cause the strains to develop daptomycin, vancomycin, and rifampin resistance.

scholarly journals Genome-Scale Metabolic Model of Caldicellulosiruptor bescii Reveals Optimal Metabolic Engineering Strategies for Bio-based Chemical Production

mSystems ◽  
2021 ◽  
Author(s):  
Ke Zhang ◽  
Weishu Zhao ◽  
Dmitry A. Rodionov ◽  
Gabriel M. Rubinstein ◽  
Diep N. Nguyen ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
High Temperatures ◽  
Plant Biomass ◽  
Metabolic Model ◽  
Industrial Applications ◽  
Cellulolytic Bacterium ◽  
Chemical Production ◽  
Content Type ◽  
Caldicellulosiruptor Bescii ◽  
Genome Scale

The extremely thermophilic cellulolytic bacterium, Caldicellulosiruptor bescii , degrades plant biomass at high temperatures without any pretreatments and can serve as a strategic platform for industrial applications. The metabolic engineering of C. bescii , however, faces potential bottlenecks in bio-based chemical productions.

scholarly journals Comprehensive Insights Into Forensic Features and Genetic Background of Chinese Northwest Hui Group Using Six Distinct Categories of 231 Molecular Markers

2021 ◽  
Vol 12 ◽  
Author(s):  
Chong Chen ◽  
Xiaoye Jin ◽  
Xingru Zhang ◽  
Wenqing Zhang ◽  
Yuxin Guo ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Single Nucleotide Polymorphisms ◽  
Genetic Background ◽  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Genetic Relationships ◽  
Population Data ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Short Tandem

The Hui minority is predominantly composed of Chinese-speaking Islamic adherents distributed throughout China, of which the individuals are mainly concentrated in Northwest China. In the present study, we employed the length and sequence polymorphisms-based typing system of 231 molecular markers, i.e., amelogenin, 22 phenotypic-informative single nucleotide polymorphisms (PISNPs), 94 identity-informative single nucleotide polymorphisms (IISNPs), 24 Y-chromosomal short tandem repeats (Y-STRs), 56 ancestry-informative single nucleotide polymorphisms (AISNPs), 7 X-chromosomal short tandem repeats (X-STRs), and 27 autosomal short tandem repeats (A-STRs), into 90 unrelated male individuals from the Chinese Northwest Hui group to comprehensively explore its forensic characteristics and genetic background. Total of 451 length-based and 652 sequence-based distinct alleles were identified from 58 short tandem repeats (STRs) in 90 unrelated Northwest Hui individuals, denoting that the sequence-based genetic markers could pronouncedly provide more genetic information than length-based markers. The forensic characteristics and efficiencies of STRs and IISNPs were estimated, both of which externalized high polymorphisms in the Northwest Hui group and could be further utilized in forensic investigations. No significant departure from the Hardy–Weinberg equilibrium (HWE) expectation was observed after the Bonferroni correction. Additionally, four group sets of reference population data were exploited to dissect the genetic background of the Northwest Hui group separately from different perspectives, which contained 26 populations for 93 IISNPs, 58 populations for 17 Y-STRs, 26 populations for 55 AISNPs (raw data), and 109 populations for 55 AISNPs (allele frequencies). As a result, the analyses based on the Y-STRs indicated that the Northwest Hui group primarily exhibited intimate genetic relationships with reference Hui groups from Chinese different regions except for the Sichuan Hui group and secondarily displayed close genetic relationships with populations from Central and West Asia, as well as several Chinese groups. However, the AISNP analyses demonstrated that the Northwest Hui group shared more intimate relationships with current East Asian populations apart from reference Hui group, harboring the large proportion of ancestral component contributed by East Asia.

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