Detection of grlA and gyrA Mutations in 344 Staphylococcus aureus Strains

1998 ◽  
Vol 42 (2) ◽  
pp. 236-240 ◽  
Author(s):  
Tong Wang ◽  
Mayumi Tanaka ◽  
Kenichi Sato
Keyword(s):  
Staphylococcus Aureus ◽  
Direct Sequencing ◽  
Single Point ◽  
Point Mutations ◽  
Single Strand Conformation Polymorphism ◽  
Fluoroquinolone Resistance ◽  
Polymorphism Analysis ◽  
Ciprofloxacin Resistance ◽  
Single Point Mutations ◽  
Length Analysis

ABSTRACT Mutations in the grlA and gyrA genes of 344 clinical strains of Staphylococcus aureus isolated in 1994 in Japan were identified by combinations of single-strand conformation polymorphism analysis, restriction fragment length analysis, and direct sequencing to identify possible relationships to fluoroquinolone resistance. Five types of single-point mutations and four types of double mutations were observed in the grlA genes of 204 strains (59.3%). Four types of single-point mutations and four types of double mutations were found in the gyrA genes of 188 strains (54.7%). Among them, the grlA mutation of TCC→TTC or TAC (Ser-80→Phe or Tyr) and the gyrAmutation of TCA→TTA (Ser-84→Leu) were principal, being detected in 137 (39.8%) and 121 (35.9%) isolates, respectively. ThegrlA point mutations of CAT→CAC (His-77 [silent]), TCA→CCA (Ser-81→Pro), and ATA→ATT (Ile-100 [silent]) were novel, as was the GAC→GGC (Asp-73→Gly) change in gyrA. A total of 15 types of mutation combinations within both genes were related to ciprofloxacin resistance (MIC ≥ 3.13 μg/ml) and were present in 193 mutants (56.1%). Strains containing mutations in both genes were highly resistant to ciprofloxacin (MIC at which 50% of the isolates are inhibited [MIC50] = 50 μg/ml). Those with the Ser-80→Phe or Tyr alteration in grlA but wild-typegyrA showed a lower level of ciprofloxacin resistance (MIC50 ≤ 12.5 μg/ml). Levofloxacin was active against 68 of 193 isolates (35.2%) with mutations at codon 80 of grlAin the presence or absence of a concomitant mutation at codon 73, 84, or 88 in gyrA (MIC ≤ 6.25 μg/ml). The new fluoroquinolone DU-6859a showed good activity with 186 of 193 isolates (96.4%) for which the MIC was ≤6.25 μg/ml.

scholarly journals Detection of gyrA Mutations among 335Pseudomonas aeruginosa Strains Isolated in Japan and Their Susceptibilities to Fluoroquinolones

1999 ◽  
Vol 43 (2) ◽  
pp. 406-409 ◽  
Author(s):  
Takashi Takenouchi ◽  
Eiko Sakagawa ◽  
Mie Sugawara
Keyword(s):  
Double Point ◽  
Direct Sequencing ◽  
Point Mutations ◽  
Single Strand Conformation Polymorphism ◽  
Fluoroquinolone Resistance ◽  
Polymorphism Analysis ◽  
Novel Mutations ◽  
Conformation Polymorphism Analysis ◽  
High Level ◽  
Conformation Polymorphism

ABSTRACT gyrA point mutations in 335 clinical Pseudomonas aeruginosa isolates were examined mainly by nonisotopic single-strand conformation polymorphism analysis and direct sequencing. Seven types of missense gyrA mutations were observed in 70 of 335 strains (20.9%), and ciprofloxacin MICs were ≥3.13 μg/ml for 63 of 70 strains (90.0%). These included two double point mutations and three novel mutations (Ala-67→Ser plus Asp-87→Gly, Ala-84→Pro, and Gln-106→Leu). Thr-83→Ile mutants were predominantly observed (63 of 70 mutants) and showed high-level fluoroquinolone resistance (ciprofloxacin MIC at which 50% of isolates are inhibited, 25 μg/ml).

scholarly journals First Characterization of Fluoroquinolone Resistance in Streptococcus suis

2006 ◽  
Vol 51 (2) ◽  
pp. 777-782 ◽  
Author(s):  
Jose Antonio Escudero ◽  
Alvaro San Millan ◽  
Ana Catalan ◽  
Adela G. de la Campa ◽  
Estefania Rivero ◽  
...  
Keyword(s):  
Horizontal Gene Transfer ◽  
Single Point ◽  
Point Mutations ◽  
Streptococcus Suis ◽  
Fluoroquinolone Resistance ◽  
Genes Encoding ◽  
Resistant Strains ◽  
Single Point Mutations ◽  
Clonal Spread

ABSTRACT We have identified and sequenced the genes encoding the quinolone-resistance determining region (QRDR) of ParC and GyrA in fluoroquinolone-susceptible and -resistant Streptococcus suis clinical isolates. Resistance is the consequence of single point mutations in the QRDRs of ParC and GyrA and is not due to clonal spread of resistant strains or horizontal gene transfer with other bacteria.

scholarly journals Genogroup I picobirnaviruses in pigs: evidence for genetic diversity and relatedness to human strains

2008 ◽  
Vol 89 (2) ◽  
pp. 534-539 ◽  
Author(s):  
K. Bányai ◽  
V. Martella ◽  
Á. Bogdán ◽  
P. Forgách ◽  
F. Jakab ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Single Point ◽  
Point Mutations ◽  
Single Strand Conformation Polymorphism ◽  
Intestinal Content ◽  
Nucleotide Sequencing ◽  
Polymorphism Analysis ◽  
Pathogenic Potential ◽  
Single Strain ◽  
Evolutionary Features

Picobirnaviruses (PBVs) are small, non-enveloped viruses with a bisegmented double-stranded RNA genome. Their pathogenic potential, ecology, and evolutionary features are largely unexplored. Here, we describe the molecular analysis of porcine PBVs identified in the intestinal content of dead pigs. Six of 13 positive samples were cloned and then subjected to single-strand conformation polymorphism analysis and nucleotide sequencing. All clones belonged to genogroup I PBVs and almost all clones clustered on separate branches from human strains. A single strain shared a notably close genetic relationship with a Hungarian human PBV strain (89.9 nt and 96.4 % aa identity). Genetic diversity was also observed among strains identified in mixed infections. Single point mutations and deleterious mutations within highly related strains suggested that PBVs exist as quasispecies in the swine alimentary tract. Clones with complete sequence identities originating from different animals suggested effective animal-to-animal transmission of the virus. Our findings indicate that infection with genogroup I PBVs is common in pigs.

scholarly journals In Vivo Selection of Campylobacter Isolates with High Levels of Fluoroquinolone Resistance Associated with gyrA Mutations and the Function of the CmeABC Efflux Pump

2003 ◽  
Vol 47 (1) ◽  
pp. 390-394 ◽  
Author(s):  
Naidan Luo ◽  
Orhan Sahin ◽  
Jun Lin ◽  
Linda O. Michel ◽  
Qijing Zhang
Keyword(s):  
Intestinal Tract ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Single Point ◽  
Point Mutations ◽  
Fluoroquinolone Resistance ◽  
Quinolone Antibiotics ◽  
Single Point Mutations ◽  
Selection Of

ABSTRACT Enrofloxacin treatment of chickens infected with fluoroquinolone(FQ)-sensitive Campylobacter promoted the emergence of FQ-resistant Campylobacter mutants which propagated in the intestinal tract and recolonized the chickens. The recovered isolates were highly resistant to quinolone antibiotics but remained susceptible to non-FQ antimicrobial agents. Specific single-point mutations in the gyrA gene and the function of the CmeABC efflux pump were linked to the acquired FQ resistance. These results reveal that Campylobacter is hypermutable in vivo under the selection pressure of FQ and highlight the need for the prudent use of FQ antibiotics.

scholarly journals Evaluation of variations in plastid DNA non-coding regions in selected species of the genus Solanum

2017 ◽  
Vol 53 (No. 3) ◽  
pp. 127-131
Author(s):  
V. Sedláková ◽  
P. Sedlák ◽  
D. Zeka ◽  
J. Domkářová ◽  
P. Doležal ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Direct Sequencing ◽  
Single Point ◽  
Point Mutations ◽  
Plastid Dna ◽  
Intraspecific Diversity ◽  
Trnl Intron ◽  
Coding Regions ◽  
Gradient Gel Electrophoresis ◽  
Single Point Mutations

The diversity of three non-coding plastid DNA loci (trnL/trnF spacer, trnV/16SrRNA spacer, trnL/trnL intron) was assessed in 16 Solanum L. species (135 individuals). Polymorphisms were detected by denaturing gradient gel electrophoresis (DGGE) and verified by direct sequencing. No intraspecific diversity and only poor interspecific diversity was detected. Unique S. mochiquense Ochoa specific length polymorphism at the trnL/trnL locus represented by duplication of an 18 bp segment was discovered. The detected DGGE interspecific trnL/trnF locus polymorphism did not specifically associate with single point mutations in the sequence confirmed by sequencing. The DGGE method was found to be a simple and cheap pre-exploring tool for mutation detection in compared DNA regions. Some identified polymorphisms can be used in the management of genetic resources.

scholarly journals Genetic Changes That Correlate with Reduced Susceptibility to Daptomycin in Staphylococcus aureus

2006 ◽  
Vol 50 (6) ◽  
pp. 2137-2145 ◽  
Author(s):  
Lisa Friedman ◽  
Jeff D. Alder ◽  
Jared A. Silverman
Keyword(s):  
Staphylococcus Aureus ◽  
Single Point ◽  
Point Mutations ◽  
Hospital Setting ◽  
Genetic Changes ◽  
Gram Positive Bacteria ◽  
Nucleotide Insertion ◽  
Single Point Mutations ◽  
Lipopeptide Antibiotic ◽  
Genome Comparisons

ABSTRACT Daptomycin is a lipopeptide antibiotic with potent activity against gram-positive bacteria. Complete-genome comparisons of laboratory-derived Staphylococcus aureus with decreased susceptibility to daptomycin and their susceptible parent were used to identify genes that contribute to reduced susceptibility to daptomycin. Selective pressure of growth in sublethal concentrations of daptomycin resulted in the accumulation of mutations over time correlating with incremental decreases in susceptibility. Single point mutations resulting in amino acid substitutions occurred in three distinct proteins: MprF, a lysylphosphatidylglycerol synthetase; YycG, a histidine kinase; and RpoB and RpoC, the β and β′ subunits of RNA polymerase. Sequence analysis of mprF, yycF, yycG, rpoB, and rpoC in clinical isolates that showed treatment-emergent increases in daptomycin MICs revealed point mutations in mprF and a nucleotide insertion in yycG, suggesting a role for these genes in decreased susceptibility to daptomycin in the hospital setting.

Cupin Variants as Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Miho Yuasa ◽  
Yosuke Nishikawa ◽  
Genji Kurisu ◽  
Shinobu Itoh ◽  
...  
Keyword(s):  
Michael Addition ◽  
In Silico ◽  
Addition Reaction ◽  
Single Point ◽  
Point Mutations ◽  
Unsaturated Ketone ◽  
Michael Addition Reaction ◽  
Beta Barrel ◽  
Cupin Superfamily ◽  
Single Point Mutations

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.

Single-Point Mutations in Qβ Virus-like Particles Change Binding to Cells

2021 ◽  
Author(s):  
Marisa L. Martino ◽  
Stephen N. Crooke ◽  
Marianne Manchester ◽  
M.G. Finn
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Virus Like Particles ◽  
Single Point Mutations

MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria
Keyword(s):  
Cell Division ◽  
Single Point ◽  
Point Mutations ◽  
Direct Interaction ◽  
Ring Formation ◽  
Z Ring ◽  
Single Point Mutations ◽  
Biochemical Analyses ◽  
Ftsz Assembly ◽  
The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

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