Search results for "MUTATION"
showing 10 items of 2830 documents
Mutation rate of bacteriophage ΦX174 modified through changes in GATC sequence context
2011
Bacteriophage ΦX174 has a relatively high mutation rate of 10⁻⁶ substitutions per nucleotide per strand copying. A thirty-fold reduction in the mutation rate was achieved by introducing seven GATC sequences in its genome. This motif allows for methyl-directed mismatch repair and is strongly avoided in nature by ΦX174 and other phages.
Reduction of nevirapine-driven HIV mutations by carbamazepine is modulated by CYP3A activity
2014
Item does not contain fulltext OBJECTIVES: The reduction in mother-to-child transmission of HIV-1 by single-dose nevirapine given at birth onset is achieved at the expense of de novo HIV-1 resistance mutations. In the VITA1 study, single-dose carbamazepine accelerated nevirapine elimination, but the accompanying trend towards fewer de novo HIV-1 mutations was statistically non-significant. METHODS: We investigated if the effect of carbamazepine was confounded by the individual variability in nevirapine metabolism and transport. RESULTS: Nine of 34 (26%) single-dose nevirapine-treated women had one or more nevirapine-associated resistance mutations, compared with 3 of 34 (9%) in the single-d…
Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily
2015
The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of case…
Simultaneous identification of campylobacters and prediction of quinolone resistance by comparative sequence analysis.
1997
Comparative sequence analysis of a 30-bp segment in the quinolone resistance-determining region of campylobacters not only allows for the detection of base changes associated with resistance but also is a powerful tool for species identification based on silent mutations.
Transcriptional expression of selected genes associated with excretion of carboxylic acids from aci mutants of Saccharomyces cerevisiae
2013
Introduction: Saccharomyces cerevisiae is an excellent model organism for studies of transcriptional regulation of metabolic processes in other eukaryotic cells including human cells. Cellular acid-base balance can be disturbed in pathologic situations such as renal acidosis or cancer. The extracellular pH of malignant solid tumors is acidic in the range of 6.5-6.9. EG07 and EG37 aci mutants of Saccharomyces cerevisiae excessively excrete carboxylic acids to glucose-containing media or distilled water. The excreted acids are Krebs and/or glyoxylate cycle intermediates. The genes restoring the wild-type phenotype have function that does not easily explain theAci phenotype.Material/Methods: I…
Transmission bottlenecks and the evolution of fitness in rapidly evolving RNA viruses
2003
We explored the evolutionary importance of two factors in the adaptation of RNA viruses to their cellular hosts, size of viral inoculum used to initiate a new infection, and mode of transmission (horizontal versus vertical). Transmission bottlenecks should occur in natural populations of viruses and their profound effects on viral adaptation have been previously documented. However, the role of transmission mode has not received the same attention. Here we used a factorial experimental design to test the combined effects of inoculum (bottleneck) size and mode of transmission in evolution of vesicular stomatitis virus (VSV) in tissue culture, and compared our results to the predictions of a …
Broadening the phenotypic spectrum and physiological insights related toEIF2S3variants
2021
Mental deficiency, epilepsy, hypogonadism, microcephaly and obesity (MEHMO) syndrome is a severe X-linked syndrome caused by pathogenic variants in EIF2S3. The gene encodes the γ subunit of the eukaryotic translation initiation factor-2, eIF2, essential for protein translation. A recurrent frameshift variant is described in severely affected patients while missense variants usually cause a moderate phenotype. We identified a novel missense variant (c.433A>G, p.(Met145Val)) in EIF2S3 in a mildly affected patient. Studies on zebrafish confirm the pathogenicity of this novel variant and three previously published missense variants. CRISPR/Cas9 knockout of eif2s3 in zebrafish embryos recapitula…
Primary Microcephaly with Novel Variant of MCPH1 Gene in Twins: Both Manifesting in Childhood at the Same Time with Hashimoto's Thyroiditis
2020
AbstractThis study is a clinical report on twin females affected by primary microcephaly who displayed at molecular analysis of heterozygous novel MCPH1 variant. The twins at the age of 10 years developed, in coincidental time, a diagnosis of autoimmune juvenile thyroiditis. The main clinical features presented by the twins consisted of primary microcephaly with occipitofrontal circumference measuring −2 or −3 standard deviation, facial dysmorphism, typical nonsyndromic microcephaly, and mild intellectual disability. Molecular analysis of the major genes involved in primary microcephaly was performed and the following result was found in the twins: MCPH1; chr8.6357416; c.2180 C > T (rs 1…
Total retinal detachment caused by a KIF11 mutation.
2017
Purpose This is a case report of bilateral retinal detachment associated with KIF11 mutation. Methods In our university hospital, an 8-week-old patient presented with a potential bilateral congenital cataract, iris atrophy, and iridocorneal contact in the left eye. An examination revealed microcephaly and edema of the dorsa of the feet. The eye examination showed a clear lens in both eyes with a dislodged anterior chamber in the left eye with vessels drawn from the iris to the lens. A retrolental white bilateral mass with vessels was also observed. The MRI and the ultrasound revealed a potential peritoneal hyperplastic glass body. Bilateral retinal detachment was diagnosed during surgery. R…
Mutations in KATNB1 Cause Complex Cerebral Malformations by Disrupting Asymmetrically Dividing Neural Progenitors
2014
SummaryExome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specificall…