Littérature scientifique sur le sujet « Mutant frequency »
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Articles de revues sur le sujet "Mutant frequency"
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Curry, John, Larissa Karnaoukhova, Gabriel C. Guenette et Barry W. Glickman. « Influence of Sex, Smoking and Age on Human hprt Mutation Frequencies and Spectra ». Genetics 152, no 3 (1 juillet 1999) : 1065–77. http://dx.doi.org/10.1093/genetics/152.3.1065.
Texte intégralRésumé :
Abstract Examination of the literature for hprt mutant frequencies from peripheral T cells yielded data from 1194 human subjects. Relationships between mutant frequency, age, sex, and smoking were examined, and the kinetics were described. Mutant frequency increases rapidly with age until about age 15. Afterward, the rate of increase falls such that after age 53, the hprt mutant frequency is largely stabilized. Sex had no effect on mutant frequency. Cigarette smoking increased mean mutant frequency compared to nonsmokers, but did not alter age vs. mutant frequency relationships. An hprt in vivo mutant database containing 795 human hprt mutants from 342 individuals was prepared. No difference in mutational spectra was observed comparing smokers to nonsmokers, confirming previous reports. Sex affected the frequency of deletions (>1 bp) that are recovered more than twice as frequently in females (P = 0.008) compared to males. There is no indication of a significant shift in mutational spectra with age for individuals older than 19 yr, with the exception of A:T → C:G transversions. These events are recovered more frequently in older individuals.
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Tanimoto, Koichi, Haruyoshi Tomita, Shuhei Fujimoto, Katsuko Okuzumi et Yasuyoshi Ike. « Fluoroquinolone Enhances the Mutation Frequency for Meropenem-Selected Carbapenem Resistance in Pseudomonas aeruginosa, but Use of the High-Potency Drug Doripenem Inhibits Mutant Formation ». Antimicrobial Agents and Chemotherapy 52, no 10 (11 août 2008) : 3795–800. http://dx.doi.org/10.1128/aac.00464-08.
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ABSTRACT The mutation frequency for carbapenem resistance in Pseudomonas aeruginosa strains that were selected with carbapenems was enhanced in the presence of subinhibitory concentrations of fluoroquinolones. The mutants showed either a loss of OprD activity or increased mexAB-oprM expression. The highest mutant isolation frequency was obtained by selection with meropenem, while doripenem inhibited mutant growth.
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Magin, Gregory K., Steven H. Robison, Nancy Breslin, Richard Jed Wyatt et Robert C. Alexander. « DNA repair and mutant frequency in schizophrenia ». Mutation Research/DNA Repair 255, no 3 (novembre 1991) : 241–46. http://dx.doi.org/10.1016/0921-8777(91)90027-m.
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Alexander, R. C., G. K. Magin, S. H. Robison et R. J. Wyatt. « DNA repair and mutant frequency in schizophrenia ». Schizophrenia Research 6, no 2 (janvier 1992) : 96. http://dx.doi.org/10.1016/0920-9964(92)90100-j.
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Nishimura, Kenji, Shanna K. Johansen, Takashi Inaoka, Takeshi Hosaka, Shinji Tokuyama, Yasutaka Tahara, Susumu Okamoto, Fujio Kawamura, Stephen Douthwaite et Kozo Ochi. « Identification of the RsmG Methyltransferase Target as 16S rRNA Nucleotide G527 and Characterization of Bacillus subtilis rsmG Mutants ». Journal of Bacteriology 189, no 16 (15 juin 2007) : 6068–73. http://dx.doi.org/10.1128/jb.00558-07.
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ABSTRACT The methyltransferase RsmG methylates the N7 position of nucleotide G535 in 16S rRNA of Bacillus subtilis (corresponding to G527 in Escherichia coli). Disruption of rsmG resulted in low-level resistance to streptomycin. A growth competition assay revealed that there are no differences in fitness between the rsmG mutant and parent strains under the various culture conditions examined. B. subtilis rsmG mutants emerged spontaneously at a relatively high frequency, 10−6. Importantly, in the rsmG mutant background, high-level-streptomycin-resistant rpsL (encoding ribosomal protein S12) mutants emerged at a frequency 200 times greater than that seen for the wild-type strain. This elevated frequency in the emergence of high-level streptomycin resistance was facilitated by a mutation pattern in rpsL more varied than that obtained by selection of the wild-type strain.
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Gnanamurthy, S., et D. Dhanavel. « Effect of EMS on Induced Morphological Mutants and Chromosomal Variation in Cowpea (Vigna unguiculata (L.) Walp) ». International Letters of Natural Sciences 22 (août 2014) : 33–43. http://dx.doi.org/10.18052/www.scipress.com/ilns.22.33.
Texte intégralRésumé :
Effect of EMS (ethyl methane sulphonate) on induced morphological mutants and chromosomal variation in cowpea was studied using five different doses of mutagen along with a control in randomized blocked design with three replications. The morphological mutants there are two types of viable and chlorophyll mutants. Viable mutant contains tall, dwarf, early maturity, late maturity, leaf mutants pod mutant and flower mutants. The frequency of chlorophyll mutant contains albino, xantha and viridis. This concentration can damage or modify important components of plant cells and have been reported to affect the morphology, anatomy, biochemistry and physiology of plants differentially depending on the concentration level. These effects include changes in the cellular structure and metabolism of the plants e.g., dilation of thylakoid membranes, alteration in photosynthesis, modulation of the antioxidative system and accumulation of phenolic compounds. The morphological and chromosomal variation was found to be mutagen sensitive in somatic cells of cowpea. It was found to increase with increasing the concentration of EMS in Cowpea plants. The chemical mutagen like ethyl methane sulphonate induces high frequency of chromosomal changes like anaphasic bridge; anaphasic laggard, anaphasic bridge and clumbing of chromosome were including control plants also observed.
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Gnanamurthy, S., et D. Dhanavel. « Effect of EMS on Induced Morphological Mutants and Chromosomal Variation in Cowpea (<i>Vigna unguiculata</i> ; (L.) Walp) ». International Letters of Natural Sciences 22 (5 août 2014) : 33–43. http://dx.doi.org/10.56431/p-i0xny2.
Texte intégralRésumé :
Effect of EMS (ethyl methane sulphonate) on induced morphological mutants and chromosomal variation in cowpea was studied using five different doses of mutagen along with a control in randomized blocked design with three replications. The morphological mutants there are two types of viable and chlorophyll mutants. Viable mutant contains tall, dwarf, early maturity, late maturity, leaf mutants pod mutant and flower mutants. The frequency of chlorophyll mutant contains albino, xantha and viridis. This concentration can damage or modify important components of plant cells and have been reported to affect the morphology, anatomy, biochemistry and physiology of plants differentially depending on the concentration level. These effects include changes in the cellular structure and metabolism of the plants e.g., dilation of thylakoid membranes, alteration in photosynthesis, modulation of the antioxidative system and accumulation of phenolic compounds. The morphological and chromosomal variation was found to be mutagen sensitive in somatic cells of cowpea. It was found to increase with increasing the concentration of EMS in Cowpea plants. The chemical mutagen like ethyl methane sulphonate induces high frequency of chromosomal changes like anaphasic bridge; anaphasic laggard, anaphasic bridge and clumbing of chromosome were including control plants also observed.
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Ingham, Neil J., Navid Banafshe, Clarisse Panganiban, Julia L. Crunden, Jing Chen, Morag A. Lewis et Karen P. Steel. « Inner hair cell dysfunction in Klhl18 mutant mice leads to low frequency progressive hearing loss ». PLOS ONE 16, no 10 (1 octobre 2021) : e0258158. http://dx.doi.org/10.1371/journal.pone.0258158.
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Age-related hearing loss in humans (presbycusis) typically involves impairment of high frequency sensitivity before becoming progressively more severe at lower frequencies. Pathologies initially affecting lower frequency regions of hearing are less common. Here we describe a progressive, predominantly low-frequency recessive hearing impairment in two mutant mouse lines carrying different mutant alleles of the Klhl18 gene: a spontaneous missense mutation (Klhl18lowf) and a targeted mutation (Klhl18tm1a(KOMP)Wtsi). Both males and females were studied, and the two mutant lines showed similar phenotypes. Threshold for auditory brainstem responses (ABR; a measure of auditory nerve and brainstem neural activity) were normal at 3 weeks old but showed progressive increases from 4 weeks onwards. In contrast, distortion product otoacoustic emission (DPOAE) sensitivity and amplitudes (a reflection of cochlear outer hair cell function) remained normal in mutants. Electrophysiological recordings from the round window of Klhl18lowf mutants at 6 weeks old revealed 1) raised compound action potential thresholds that were similar to ABR thresholds, 2) cochlear microphonic potentials that were normal compared with wildtype and heterozygous control mice and 3) summating potentials that were reduced in amplitude compared to control mice. Scanning electron microscopy showed that Klhl18lowf mutant mice had abnormally tapering of the tips of inner hair cell stereocilia in the apical half of the cochlea while their synapses appeared normal. These results suggest that Klhl18 is necessary to maintain inner hair cell stereocilia and normal inner hair cell function at low frequencies.
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Waddell, D. R., K. Duffy et G. Vogel. « Cytokinesis is defective in Dictyostelium mutants with altered phagocytic recognition, adhesion, and vegetative cell cohesion properties. » Journal of Cell Biology 105, no 5 (1 novembre 1987) : 2293–300. http://dx.doi.org/10.1083/jcb.105.5.2293.
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Mutants that have been selected for defects in phagocytic recognition, adhesion, and vegetative cell-cell cohesion were found to be larger and more highly multinucleate than their parent strain. This defect is associated with the complex mutant phenotype of these mutants since revertants of the mutants coordinately acquire the wild-type phenotype for all of the defects. The larger size and multinuclearity were due to a high frequency of failure of cytokinesis in cells of wild-type size. This was shown by purifying the small cells in mutant populations and observing their growth and cell division. The mutant phenotype is more penetrant during axenic growth. Most of the mutants are not multinucleate when grown on bacteria. Recently, new mutants have been isolated that are also multinucleate when grown on bacteria by a strong selection procedure for non-adhesion to tissue culture dishes. The pleiotropic mutant phenotype and the greater penetrance of the mutant phenotype in axenic culture can be explained by hypothesizing a deficiency in a membrane component of the actomyosin motor that is involved in all of the processes defective in the mutants.
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Criss, Alison K., Kevin M. Bonney, Rhoda A. Chang, Paul M. Duffin, Brian E. LeCuyer et H. Steven Seifert. « Mismatch Correction Modulates Mutation Frequency and Pilus Phase and Antigenic Variation in Neisseria gonorrhoeae ». Journal of Bacteriology 192, no 1 (23 octobre 2009) : 316–25. http://dx.doi.org/10.1128/jb.01228-09.
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ABSTRACT The mismatch correction (MMC) system repairs DNA mismatches and single nucleotide insertions or deletions postreplication. To test the functions of MMC in the obligate human pathogen Neisseria gonorrhoeae, homologues of the core MMC genes mutS and mutL were inactivated in strain FA1090. No mutH homologue was found in the FA1090 genome, suggesting that gonococcal MMC is not methyl directed. MMC mutants were compared to a mutant in uvrD, the helicase that functions with MMC in Escherichia coli. Inactivation of MMC or uvrD increased spontaneous resistance to rifampin and nalidixic acid, and MMC/uvrD double mutants exhibited higher mutation frequencies than any single mutant. Loss of MMC marginally enhanced the transformation efficiency of DNA carrying a single nucleotide mismatch but not that of DNA with a 1-kb insertion. Unlike the exquisite UV sensitivity of the uvrD mutant, inactivating MMC did not affect survival after UV irradiation. MMC and uvrD mutants exhibited increased PilC-dependent pilus phase variation. mutS-deficient gonococci underwent an increased frequency of pilin antigenic variation, whereas uvrD had no effect. Recombination tracts in the mutS pilin variants were longer than in parental gonococci but utilized the same donor pilS loci. These results show that gonococcal MMC repairs mismatches and small insertion/deletions in DNA and also affects the recombination events underlying pilin antigenic variation. The differential effects of MMC and uvrD in gonococci unexpectedly reveal that MMC can function independently of uvrD in this human-specific pathogen.
Thèses sur le sujet "Mutant frequency"
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Cannons, Jennifer. « An increase in the frequency of hprt mutant T lymphocytes in the peripheral blood, synovial fluid, and synovial tissue of RA patients ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28406.pdf.
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Cannons, Jennifer. « An increase in the frequency of hprt mutant T lymphocytes in the peripheral blood, synovial fluid, and synovial tissue of rheumatoid arthritis patients ». Thesis, University of Ottawa (Canada), 1997. http://hdl.handle.net/10393/9964.
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I used the hypoxanthine guanine phosphoribosyl transferase (hprt) clonal assay to determine the in vivo frequency of mutant T cells (FMC) from the peripheral blood, synovial fluid, and synovial tissue of rheumatoid arthritis (RA) patients and controls. The results demonstrate that there is an increased FMC in the peripheral blood of RA patients compared to controls. There was also a significant elevation in the corrected FMC (cFMC), which takes in to account the cloning efficiency of the T cells, in the peripheral blood of RA patients compared to controls. There is an elevated FMC and cFMC in synovial fluid of RA patients compared to the peripheral blood of controls. However. the FMC and cFMC from the peripheral blood of unselected RA patients from the outpatient clinic is not significantly different than from the synovial fluid of RA patients suggesting that the synovial fluid does not contain the necessary mitogenic and mutagenic factors to induce T cell genetic damage. The FMC and cFMC from RA and osteoarthritis (OA) synovium is approximately ten fold greater than the FMC and cFMC from the peripheral blood of the same patients which suggests that the mitogenic and genotoxic environment of the inflamed synovium is capable of inducing T cell mutations. There was no significant difference in the cloning efficiency of T cells (CE), FMC, and cFMC from the peripheral blood of RA patients with 'active' or 'inactive' disease. No correlation between the cFMC from the peripheral blood of RA patients and clinical disease parameters and patient medication was found. (Abstract shortened by UMI.)
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Ferreira, Rita Joana Rodrigues da Silva Rua. « Cilia motility studies in zebrafish embryos ». Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/7984.
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A thesis submitted in fulfilment of the requirements for the degree of Masters in Molecular Genetics and BiomedicineMotile ciliary dysfunctions cause specific Ciliopathies that affect mainly the respiratory tract, fertilization and left-right body establishment. The embryonic organ where left-right decisions are first taken is called the organizer, a ciliated organ where a leftward cilia driven fluid-flow is generated. The organizer is named node in the mouse and Kupffer’s vesicle (KV) in zebrafish. The correct left-right axis formation is highly dependent on signaling pathways downstream of such directional fluid-flow. Motile cilia need to be coordinated and Ciliary Beat Frequency (CBF) is characteristic of different types of cilia depending on their function. Using zebrafish as a model, our group has been studying cilia length regulation and motility in wild-type and deltaD-/- mutant embryos. Recently, we showed that Notch signalling was directly involved in the control of cilia length in the KV cells given that the deltaD-/- mutant present shorter KV cilia. The goal of this project was to characterize the CBF of deltaD-/- KV cilia vs. wild-type cilia and reveal how potential differences in CBF impact on KV fluid flow, using spectral analysis associated with highspeed videomicroscopy. By decomposing and comparing the obtained CBF with Fast Fourier Transform, we identified two major populations of motile cilia in wild-type as well as in deltaD-/- mutant embryos. However, we found the CBF populations had differential relative contributions and different distributions between wild-type and mutant embryos. Furthermore, by measuring the velocity of native particles we studied the KV fluid-flow and concluded that the dispersion of the flow velocity was much wider in the deltaD-/- mutants. On the other hand, based on a gene expression study of motility genes downstream of DeltaD, we concluded that motility related genes (dnah7, rsph3 and foxj1a) were deregulated in the mutants. During this project we generated data that led to new hypotheses that will allow us to test the causality between the described correlations.
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Kamiya, Regianne Umeko. « Analise da frequencia e da expressão de genes de biossintese de mutacinas em isolados de Streptococcus mutans ». [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288629.
Texte intégralRésumé :
Orientador: Reginaldo Bruno GonçalvesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Esta tese, apresentada na forma de 3 artigos, teve por objetivos: (1) analisar a freqüência dos genes de produção de mutacinas I, II, III e IV, em genótipos de S. mutans isolados de indivíduos cárie-ativos e livres de cárie, (2) analisar a freqüência dos genes de produção das mutacinas I, II, III, IV, N, B-Ny 266, 1140 e genes homólogos às bacteriocinas, identificadas em outras espécies bacterianas, em cepas de S. mutans isolados de crianças, bem como detectar a expressão diferencial dos genes identificados, em células de S. mutans crescidas na condição planctônica e séssil, (3) analisar a expressão dos genes de produção das mutacinas I, II e proteínas kinases CiaH, Dgk e ComD, em diferentes fases do crescimento planctônico e séssil. O rastreamento e a freqüência dos genes estruturais de diferentes mutacinas em isolados de S. mutans, foram realizados pela técnica de PCR e a análise da expressão gênica, pela técnica de RT-PCR semi-quantitativa. Os estudos, apresentados nesta tese, demonstraram o papel das mutacinas como um fator de virulência, altamente diversificado entre a espécie S. mutans, e relacionado com o risco de cárie. Este fator de virulência, pode ser regulado por mecanismos quorum-sensing, sendo assim, dependente da condição de crescimento planctônica ou séssil. A regulação da produção de mutacinas, por mecanismos quorum-sensing, pode representar uma vantagem seletiva à espécie produtora, principalmente em ambiente complexo, como o biofilme dental e lesões de cárie. Futuramente, mais estudos serão necessários para identificar novos determinantes genéticos, necessários para a síntese de substâncias semelhantes às mutacinas, bem como, identificar os mecanismos e componentes, que modulam a expressão deste importante fatorde virulência em S. mutans
Abstract: This thesis, comprised of 3 manuscripts was designed (1) to analyse the frequency of biosynthesis genes of the mutacins types I, II, III and IV, in S. mutans isolated from caries-affected and caries-free individuals, (2) to analyse the frequency of biosynthesis genes of the mutacins types I, II, III, IV, N, B-Ny 266, 1140 and genes homologues to bacteriocins identified in other bacterial species, in S. mutans isolated from children, in addition, to detect the differential expression of these genes, in S. mutans cells grown in planktonic and sessil conditions, (3) and to analyse the expression of the mutacins I and II production genes and kinase proteins genes (ciaH, dgk e comD), in different phases of the planktonic and sessile growth. The screening and frequency of the mutacins structural genes in S. mutans isolates were realized by PCR technique and the analysis of genetic expression, by RT-PCR semiquantitative method. The studies, presented in this thesis, demonstrate the role of mutacins as a virulence factor, highly diverse among S. mutans, and related to risk of dental caries. The mutacins production may be regulated by quorum-sensing mechanisms and is dependent on planktonic and sessile conditions. The modulation by quorum-sensing mechanisms may represent a selective advantage for producer S. mutans strain, mainly in complex environments as the dental biofilm and caries. Hereafter, more studies will be necessary to identify new genetic determinants for synthesis of mutacin-like substances and elucidate the mechanisms and components that modulate the genetic expression of this important virulence factor in S. mutans
Doutorado
Microbiologia e Imunologia
Doutor em Biologia Buco-Dental
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Gradinger, Abigail. « Atypical methylmalonic aciduria : frequency of mutations in the methylmalonyl-CoA epimerase (MCEE) gene ». Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101848.
Texte intégralRésumé :
Methylmalonic aciduria results from defects in the enzyme methylmalonyl-CoA mutase and from defects in the synthesis of the enzyme's cofactor adenosylcobalamin. Two patients who excrete methylmalonic acid have been shown to have a homozygous nonsense mutation in the methylmalonyl-CoA epimerase gene (MCEE). To further understand the causes of methylmalonic acid excretion, the MCEE gene was sequenced in 229 patients who excreted methylmalonic acid for which no cause was known. Mutations were detected in five patients. Fusion of fibroblast lines from two patients with a homozygous nonsense mutation in MCEE did not result in correction of [14C]propionate incorporation toward control values while the defect in these fibroblasts was complemented by mut, cblA, and cblB fibroblasts. Transfection with wild-type MCEE cDNA resulted in correction of the biochemical phenotype in cells from both patients. These experiments support the hypothesis that a defective epimerase enzyme can be a cause of elevated methylmalonic acid excretion.
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Francisco, Silvana Boldrini. « Estudo in situ da relação entre a frequencia de exposição a sacarose, carie em esmalte dental humano e contagem de estreptococos do "grupo mutans" na placa dental ». [s.n.], 1995. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289263.
Texte intégralRésumé :
Orientador: Jaime A. CuryDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: As relações quantitativas entre frequência do consumo de sacarose, cárie dental e contagem de Estreptococos do "grupo mutans" não estão bem estabelecidos. Assim, foi realizado um estudo in situ utilizando-se um delineamento experimental do tipo cnlzado (4x4) em 04 etapas de 28 dias. doze voluntários usando dispositivos intra-orais palatinos, contendo 04 blocos de esmalte dental humano (3x3 mm), participaram desta pesquisa. Os voluntários gotejaram sobre os blocos dentais solução de sacarose a 20% na freqüência de 0 (zero) a 8x/dia. Os blocos dentais estavam protegidos por uma tela plástica e os voluntários utilizaram para sua higiene bucal dentifrício não fluoretado, mas a água consumida pelos mesmos era fluoretada (0.70 ppm). Após cada etapa a placa dental formada sobre os blocos foi coletada, pesada, homogeneizada e analisada em termos de contagem de Estreptococos do "grupo mutans" (UFC/mg) usando meio seletivo SB20. Os blocos dentais limpos, embutidos, seccionados e polidos para a determinação da dureza Knoop (KHN) do esmalte. Foram feitas indentações a 10 'mu'm de superfície utilizando microdurômetro SHIMADZU HM 2000 e carga de 25 g por 30 segundos. Os resultados microbiológicos observados em termos de média + desvio padrão da média de UFC/mg foram respectivamente em relação a exposição a sacarose de 0 (zero), 2, 4, 8x/dia: 26,72 '+ ou ¿' 13,36A; 46,72 '+ ou ¿' 30,81A; 102,44 '+ ou ¿' 53,34A e 52,18 '+ ou ¿' 21;48A, sendo que médias seguidas de mesma letra não diferem estatisticamente a nível de 5%. Quanto a dureza do esmalte diferenças significativas (p<0,05) com relação a área total só foram observadas quando a exposição a sacarose 8x/dia, resultado este semelhante quando se analisa a cada distância da superfície dental. Conclui-se que perdas de mineral só foram significativas quando da exposição a sacarose 8x/dia, não havendo entretanto relação com a contagem de Estreptococos do "grupo mutans"
Abstract: The quantitative relationship among frequency of sucrose intake, dental caries and S. mutans counts are not well established. Therefore, it was performed an in situ study utilizing an experimental design of the crossover type (4x4) in four phases of 28 days. Twelve volunteers using intra-oral palatal appliances, containing 4 blocks of human dental enamel (3x3 mm) participated in this research. The volunteers dropped on the dental blocks, 20% sucrose solution in a frequency from 0 (zero) to 8x/day. The dental blocks were protected by a plastic cover and the volunteers used for their bucal hygiene, non fluoridated dentifrice, but the water consumed by them was fluoridated (0.70 ppm). After each phase, the dental plaque formed on the blocks was collected, weighed, homogenized and assessed for S. mutans count (CFU/mg) using selective media. The dental blocks were clean, embedded, cut and polished to the Knoop hardness determination (KHN) of the enamel. It was done indentations at 10 'mu¿m of the surface using SHIMADZU H 2000 microhardness tester and 25 g load for 30 sec. The microbiological results in average '+ or ¿' standard deviation of the media of CFU/mg were, respectively in relation to the sucrose exposure of 0 (zero), 2, 4, 8x/day: 26.72 '+ or ¿'13.36A; 46.72 '+ or ¿' 30.81A; 102.44 '+ or ¿'53.34A and 52.18 '+ or - ' 21.48A . The media followed by the same letter are not statistically different at the 5% level. In the enamel hardness test, significative differences (p<0.05) in relation to the total area only were observed when the sucrose exposure was 8x/day, similar results were obtained when we assessed at each distance the dental surface. We can conclude that mineral loss only was significative when the sucrose exposure was 8x/day, although there was not a relationship to the S. mutans counts
Mestrado
Biologia e Patologia Buco-Dental
Mestre em Odontologia
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Fissore, Andrea Carla. « Estudo da frequencia do alelo mutante delta 32 do gene CCR5 em uma produção de individuos infectados pelo virus da imunodeficiencia humana (HIV) atendidos no HC/UNICAMP ». [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310664.
Texte intégralRésumé :
Orientador: Marcelo de Carvalho RamosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Objetivo: Deternllnar a freqüência do alelo recessivo ccr-5 em população de indivíduos infectados pelo HIV -1. Material e Métodos: Foram estudados 187 pacientes, que freqüentam os ambulatórios da Disciplina de Moléstias Infecciosas do Hospital das Clínicas da UNICAMP. Foram selecionados pacientes de ambos os sexos com testes positivos para o anti-HIVl por ELISA e Westem-Blot, em qualquer fase clínica da doença. Para amplificação foram utilizados os seguintes primers: 5'-CCTGGCTGTCGTCCATGCTG-3' e 5'CTGATCTAGAGCCATGTGCACAACTCT-3'. Após a desnaturação a 94°C por 5min, seguiram-se 34 ciclos de: 94°C por lmin; 57°C por lmin; 72°C por lmin e extensão final a 72°C por 7min. A seguir, foi realizada a digestão enzimática com 1 J.lg de cada amostra, incubadas por 60min à 37°C com 10U de EcoRI. Foram também deternllnadas a carga viral pela técnica do NASBA e deternllnação de subpopulações linfocitárias por citometria de fluxo (Ortho Diagn.). Resultados e Conclusões: Do total de 187 indivíduos analisados, 15 apresentaram padrões de restrição do produto de PCR compatíveis com heterozigose para a deleção delta 32 (freqüência=8,02%). Essa freqüência é semelhante à encontrada em populações caucasianas européias. Com respeito à carga viral e quantidade de células CD4 e CD8, os dados foram prejudicados pela administração de medicação antiretroviral na maioria desses indivíduos. Todos os pacientes que apresentavam a mutação e que pud~ram ser classificados clinicamente possuíam estadiamento B2 ou maior
Abstract: Previous studies have shown a relationship between a 32-base-pair deletion within the J3-chemokine receptor 5 (ccr5) gene and the acquisition and progression of the Acquired Human Immunodeficiency Syndrome (AIDS). Several. populations have been tested concerning this deletion, and it was found that Caucasians have a higher probability of bearing this defect, whereas in black and japanese populations it is virtually absent. In Brazil, no studies have been done to estimate this frequency in HIV infected populations, so faro In an urban brazilian population 93% of individuaIs tested showed normal CCR-5 anele and 7% were heterozygous CCRS/ ~ccr5. In this study 187 HIV-infected persons were tested to determine the prevalence of this mutation. Genomic DNA samples were amplified using primers producing a 735bp fragment, which was submmited to c1eavage with EcoRl. Normal homozygous aneles showed two fragments of 332 and 403 bp, and in heterozygous aneles an additional371 bp fragment was found. No homozygous individuaIs were found in this population, and the frequency ofheterozygous CCR5/~ccr5 was found to be 8,02%
Mestrado
Ciencias Basicas
Mestre em Clinica Medica
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Kachan, Ksenia. « Závislost velikosti proudu IKs kanálu srdce na stimulaci ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401014.
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This diploma thesis deals with study of the rate-dependence of the magnitude of a current through the heart channel that conducts slowly activating component of delayed rectifier outward current (IKs). This property is very important for the IKs channel function. When other repolarizing currents are insufficient, but also when the heart rate accelerates, especially during elevated sympathetic tone, IKs provides so-called repolarization reserve, which prevents excessive lengthening of cardiac action potential repolarization. The IKs channel structure is encoded by the KCNQ1 (pore-forming -subunit) and KCNE1 (modulatory -subunit) genes. Mutations in these genes disrupt the physiological function of the IKs channel and cause inherited arrhythmogenic syndromes, especially long QT syndrome (LQTS). Such mutations include the c.926C>T (p.T309I) mutation in the KCNQ1 gene, which results in LQTS type 1 in heterozygous carriers. The theoretical part of the thesis provides basic information about the IKs channel and the patch clamp technique, this knowledge is necessary for the practical part. The experimental part is focused on cultivation of the CHO cell line and its transient transfection for subsequent electrophysiological measurements by whole-cell patch clamp technique to study the dependence of the IKs magnitude on stimulation frequency, both in the wild type channels (i.e. without mutation) and in those with cotransfected wild type and T309I subunits.
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Lin, Guan-Lu, et 林冠如. « The Study of Mutant Frequency Induced by Ionizing Radiation in hprt Gene ». Thesis, 1999. http://ndltd.ncl.edu.tw/handle/09433573382276580375.
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碩士國立陽明大學
醫學生物技術研究所
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The main purpose of the research project is to study the effect of ionizing radiation to HPRT gene. There are two separate, but related, subjects studied in this project. The first part was to investigate the mutant frequency of hprt gene induced by ionizing radiation in TK6 human lymphoblast cells. The second part was to study the difference of radiosensitivity between three human nasopharyngeal carcinoma (NPC) cell lines obtained from the NPC prevalent regions, i.e. Taiwan (CG1), China (CNE1) and Hong Kong (HK1). The purpose of this study is to find the correlation between the radiosensitivity and the hprt gene mutant frequency. The results of the first study showed that radiation-induced hprt gene mutant frequency of TK6 cells was (5.01 1.82) ×10-6 and was significantly higher than that of spontaneous mutant frequency which was (1.43 0.53) ×10-6 (p<0.01). This finding indicates that mutant frequency at HPRT gene locus can be induced by ionizing radiation. The results of the second study showed that D10 were 5.5 Gy for CNE1 cell, 6.75 Gy for CG1 cell and 7.0 Gy for HK1 cell, respectively. This result indicates that the CNE1 cells were the most radiosensitive among the three cell lines. The results also proved that mutant frequency at HPRT gene locus induced by ionizing radiation was increased both in CNE1 and HK1 cells. However, CNE1 cells was less mutable compared with HK1 cells. This finding indicates that the negative correlation exists between the radiosensitivity and the induced mutant frequency, i.e. the more radiosenstive the cells were the lower mutant frequency they were induced. This hypomutability for more radiosensitive cells found in NPC cells was consistent with the study found in bladder cancer cell lines reported by other investigators.
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NANNELLI, CATERINA. « Somatic mutation rate and cancer : an exploratory study of mutant frequency in classical Philadelphia-negative myeloproliferative neoplasms ». Doctoral thesis, 2019. http://hdl.handle.net/2158/1157579.
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Oncogenesis is tightly related to the occurrence of somatic mutations. Somatic mutations are constantly produced by DNA replication processes, as the activity of DNA polymerases and DNA repair systems is highly efficient, but not perfect. The great part of spontaneous somatic mutations is irrelevant to cancer, but a very small fraction of them is oncogenic. Therefore, the individual predisposition to develop somatic mutations may be considered as a risk factor for tumor development. In order to investigate whether there is any association between the rate of occurrence of somatic mutations and the individual risk of developing cancer, we used the flow cytometry PIGA mutant assay to measure the mutant frequency in peripheral blood granulocytes of 177 healthy subjects and of a cohort of 195 patients affected by Philadelphia-negative classical MPN.
Livres sur le sujet "Mutant frequency"
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Hanel, Jerry. Mutant Frequency. Independently Published, 2019.
Trouver le texte intégralChapitres de livres sur le sujet "Mutant frequency"
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Nakagawa, Hitoshi. « History of mutation breeding and molecular research using induced mutations in Japan. » Dans Mutation breeding, genetic diversity and crop adaptation to climate change, 24–39. Wallingford : CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0003.
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Abstract Following the construction of the Gamma Field at the Institute of Radiation Breeding in 1960, mutation breeding was accelerated in Japan. The facility is used, with a radiation dose up to 2 Gy/day (ca. 300,000 times that of natural background), to induce mutations at a higher frequency than occurs in nature. There have been 318 direct- use mutant cultivars representing 79 species generated through irradiation of gamma-rays, X-rays, ion beams and chemicals and somaclonal variation. Approximately 79% of these direct-use cultivars were induced by radiation. There have been 375 indirect-use mutant cultivars, including 332 rice, of which 162 cultivars (48.8%) were derived from the semi-dwarf mutant cv. 'Reimei'. The economic impact of these mutant cultivars, primarily of rice and soybean, is very large. Some useful mutations are discussed for rice, such as low digestible protein content, low amylose content, giant embryo and non-shattering. Useful mutations in soybean such as radiosensitivity, fatty acid composition and super-nodulation have been identified. Japanese pear and apple resistant to Alternaria disease have also been identified. The achievements of biological research such as characterization and determination of deletion size generated by gamma-rays, the effect of deletion size and the location, and a mechanism of dominant mutation induction are identified. Similarly, genetic studies on mutations generated through the use of gamma-ray induced mutations, such as phytochrome response, aluminium tolerance, stay-green (Mendel's gene) and epicuticular wax have also been conducted. Mutation breeding is a very useful technology for isolating genes and for elucidating gene functions and metabolic pathways in various crops.
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Abe, Tomoko, Hiroyuki Ichida, Yoriko Hayashi, Ryouhei Morita, Yuki Shirakawa, Kotaro Ishii, Tadashi Sato, Hiroki Saito et Yutaka Okumoto. « Ion beam mutagenesis - an innovative and effective method for plant breeding and gene discovery. » Dans Mutation breeding, genetic diversity and crop adaptation to climate change, 411–23. Wallingford : CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0042.
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Abstract We have developed a unique technology for mutation induction of plants using energetic ion beams at the RI Beam Factory (RIBF) of Rikagaku Kenkyūjo (RIKEN) (Institute of Physical and Chemical Research). Ion beams effectively induce mutations at relatively low doses without severely inhibiting growth. The irradiation treatment can be given to various plant materials and mutation can be induced in a short time, between seconds and a few minutes. The linear energy transfer (LET) of ions depends on the nuclide and velocity. Since LET value affects the mutation frequency, it is an important parameter to determine the most effective irradiation condition in mutagenesis. We determined the most effective dose in each LET for mutation induction in imbibed rice seeds. Subsequently, we analysed the mutated DNA responsible for the phenotype in morphological mutants. Most of the mutations were small deletions of less than 100 bp. Irradiations of C-ions and Ne-ions are effective for plant breeding because of the very high mutation rate and sufficient energy to disrupt a single gene. On the other hand, all mutations induced by Ar-ion (290 keV/μm) irradiation were large deletions ranging from 176 bp to approximately 620 kb. The average number of mutations in the target exon regions was 7.3, 8.5 and 4.3 per M3 mutant plant in C-ions, Ne-ions and Ar-ions, respectively. The number of mutations induced by heavy-ion irradiation was relatively small. We could identify six responsible genes for eight mutants induced by C-ion and Ne-ion irradiations and two responsible genes for four mutants induced by Ar-ion irradiation. Three of these were genes not previously described.
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Yusop, Mohd Rafii, Yusuff Oladosu, Abdul Rahim Harun, Asfaliza Ramli, Ghazali Hussin, Mohd Razi Ismail et Norhani Abdullah. « Application of mutation techniques and genotype × environment interaction for grain yield in ion beam induced mutant rice lines tested in multiple locations in Malaysia. » Dans Mutation breeding, genetic diversity and crop adaptation to climate change, 226–34. Wallingford : CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0023.
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Abstract Genotype evaluation for stability and high yield in rice is an important factor for sustainable rice production and food security. These evaluations are essential, especially when the breeding objective is to release rice with high yields, adaptability and stability for commercial cultivation. To achieve this objective, this study was carried out to select high-yielding rice genotypes induced by ion beam irradiation. Seeds of the rice variety 'MR219' were subjected to different doses of 320 MeV carbon-ion beam irradiation to determine the optimum dose to produce high mutant frequency and spectrum. The optimum dose was 60 Gy. After several cycles of selection and fixation between 2009 and 2014 (M0-M6), six prospective lines with desirable characters were selected at the M6 generation. The selected mutant lines along with other mutant varieties were then tested at five locations in two planting seasons to select high-yielding and stable genotypes. The experiment was conducted in a randomized complete block design with three replications across the locations and seasons. The pooled analysis of variance revealed highly significant differences (p ≤ 0.01, 0.05) among genotypes, among locations and among genotypes by location by season (G×L×S interaction) for the yield traits except for seasons and genotype by season (G×S interaction). Based on univariate and multivariate stability parameters, rice genotypes were classified into three main categories. The first group comprised genotypes with high yield stability along with high yield per hectare. These genotypes include ML4 and ML6 and are widely adapted to diverse environmental conditions. One line exhibited high yield per hectare but low stability; this genotype (ML9) is suitable for specific environments. The last group had low yield per hectare and high stability and included 'MR220', 'Binadhan4' and 'Binadhan7'. This final group is more suitable for breeding specific traits or perhaps has yield component compensation. Hence, rice mutant lines ML4 and ML6 were recommended for commercial cultivation in Malaysia.
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Yin, Liu-hua, Lan Zhang, Ling Liu, Hongfei Zhang, Li Hou et De-pei Wang. « Exploitation of a KU70-Deficient Mutant for Improving Gene Deletion Frequency in Aspergillus niger ». Dans Lecture Notes in Electrical Engineering, 105–15. Singapore : Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4801-2_11.
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Yamakawa, Mineo, Jeffrey Warmke, Scott Falkenthal et David Maughan. « Frequency Analysis of Skinned Indirect Flight Muscle From a Myosin Light Chain 2 Deficient Mutant of Drosophila Melanogaster with a Reduced Wing Beat Frequency ». Dans Advances in Experimental Medicine and Biology, 455–60. Boston, MA : Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-6003-2_38.
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Melvold, R. W., et H. I. Kohn. « Spontaneous Frequency of H-2 Mutations ». Dans Transgenic Mice and Mutants in MHC Research, 3–13. Berlin, Heidelberg : Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75442-5_1.
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« Mutant Frequency ». Dans Encyclopedia of Genetics, Genomics, Proteomics and Informatics, 1295. Dordrecht : Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6754-9_11003.
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COLE, J., C. F. ARLETT, M. H. L. GREEN, S. E. JAMES, L. HENDERSON, H. COLE, M. SALA-TREPAT, R. BENZI, M. L. PRICE et B. A. BRIDGES. « Measurement of Mutant Frequency to 6-Thioguanine Resistance in Circulating T-lymphocytes for Human Population Monitoring ». Dans New Trends in Genetic Risk Assessment, 175–203. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-12-388176-2.50021-7.
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Thompson, Gilbert R. « Familial hypercholesterolaemia ». Dans Oxford Textbook of Endocrinology and Diabetes, 1667–73. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199235292.003.1240.
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Familial hypercholesterolaemia (OMIM 143890) is characterized by hypercholesterolaemia from birth, with the subsequent development of cutaneous and tendon xanthomas and premature onset of atherosclerosis, as first described by Müller over 70 years ago (1). Myant (2) noted that the monogenically determined increase in plasma cholesterol was largely confined to low-density lipoprotein (LDL) cholesterol and Goldstein and Brown (3) showed that the increase in LDL was due to mutations of the gene encoding the formation of LDL receptors, leading to defective catabolism of LDL. Over 1000 variations in the LDL receptor gene have now been described, most of which can cause familial hypercholesterolaemia (4). Usually only one mutant gene is inherited, which gives rise to the heterozygous form of the disease. Rarely, inheritance of two identical mutant alleles occurs, giving rise to homozygous familial hypercholesterolaemia. Inheritance of two mutations results in compound heterozygosity, which is clinically indistinguishable from genetically homozygous familial hypercholesterolaemia. The frequency of familial hypercholesterolaemia in the populations of Europe and North America averages 0.2%, but in some parts of the world it is much higher. Regions with an increased prevalence of familial hypercholesterolaemia include Lebanon, South Africa, and the Canadian province of Quebec. In each instance this is attributable to an unusually high frequency of one or two mutations within the population, such as the Lebanese allele, the Afrikaner 1 and 2 mutations, and the French Canadian allele. In South Africa and Canada the increased prevalence of familial hypercholesterolaemia represents a founder gene effect traceable to immigrant settlers from Europe, whereas in Muslim communities it reflects the frequency of first-cousin marriages. In notable contrast is the multiplicity of mutations found among familial hypercholesterolaemia patients in the UK, as shown in Fig. 12.2.2.1. An identical clinical syndrome to familial hypercholesterolaemia can occur as a result of inheritance of a mutation at the apoB locus, which results in a functionally defective form of LDL (5). This disorder, familial defective apoB-100 or FDB (OMIM 144010), has a frequency of 0.1% in people of European descent but has never been described in Japan. Rarely, familial hypercholesterolaemia is caused by dominantly inherited gain of function mutations of a gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) (OMIM 603776), which results in increased degradation of LDL receptors and an unusually severe clinical phenotype (6). It can also be caused by recessively inherited loss of function mutations of a gene encoding a protein involved in the clathrin-mediated internalization of the LDL receptor (6), which results in a milder phenotype than dominantly inherited forms of the condition and is known as autosomal recessive hypercholesterolaemia (OMIM 603813). A recent survey detected mutations of the LDL receptor, apoB, and PCSK9 genes in only 62% of patients with clinically definite familial hypercholesterolaemia (7), raising the likelihood that mutations of genes encoding other proteins involved in LDL metabolism remain to be discovered.
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Griffiths, William J. H., et Timothy M. Cox. « Hereditary haemochromatosis ». Dans Oxford Textbook of Medicine, sous la direction de Timothy M. Cox, 2098–114. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0233.
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Hereditary haemochromatosis syndromes are inherited disorders whereby inappropriate absorption of iron by the small intestine leads to iron deposition in the viscera, endocrine organs, and other sites, causing structural injury and impaired function. The most common form is classical adult (HFE-related) haemochromatosis, but other forms are recognized. Extended genetic platforms are increasingly used for specific diagnosis and noninvasive methods are increasingly used to evaluate hepatic damage. The mainstay of treatment is venesection although iron chelation therapy is an emerging oral alternative. Unravelling the molecular genetics of haemochromatosis is underpinning promising new therapies for disorders of iron homeostasis. Classical adult (HFE-related) haemochromatosis: aetiology and pathogenesis—inherited as a recessive trait and due to mutations in the major histocompatibility complex class I-related HFE gene that appear to reduce liver production of hepcidin. The principal mutant allele of HFE, designated C282Y, is carried by approximately 1 in 10 individuals of European ancestry, hence around 1 in 200 are homozygotes, usually with biochemical abnormalities of iron storage that may lead to full-blown clinical haemochromatosis. Clinical features—expression of disease may range from slight abnormalities of blood parameters that reflect iron metabolism to the established clinical syndrome of cutaneous pigmentation, cardiomyopathy, endocrine failure (especially diabetes mellitus and hypogonadism), arthritis, and pigment cirrhosis. Diagnosis—usually established by demonstrating abnormalities of iron metabolism. Molecular analysis of the HFE gene, in particular for homozygosity for the C282Y allele, is confirmatory. Management and prognosis—this is directed to the removal of iron by phlebotomy until the serum ferritin concentration is reduced to within the low normal range, after which the frequency of phlebotomy is reduced. Family members—first-degree relatives should be offered screening.
Actes de conférences sur le sujet "Mutant frequency"
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Ladokhin, Alexey S., Henryk M. Malak, Michael L. Johnson, Joseph R. Lakowicz, L. Wang, A. W. Steggles et Peter W. Holloway. « Frequency-domain fluorescence of mutant cytochrome b5 ». Dans OE/LASE '92, sous la direction de Joseph R. Lakowicz. SPIE, 1992. http://dx.doi.org/10.1117/12.58250.
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Masotti, Cibele, Filipe F. Santos, Anamaria A. Camargo et Pedro A. F. Galante. « Abstract B65 : Measuring intratumoral heterogeneity with a mutant-allele frequency score across distinct cancer types ». Dans Abstracts : AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine ; May 4-6, 2017 ; São Paulo, Brazil. American Association for Cancer Research, 2018. http://dx.doi.org/10.1158/1557-3265.tcm17-b65.
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Polivka, T., D. Engst, J. Dian, P. Kroh, J. Pšenčík, M. Vácha, L. Nedbal, W. I. M. Vermaas et J. Hála. « Persistent Spectral Hole Burning In The Antenna Protein CP47 Of Synechocystis SP. Mutant H114Q ». Dans Spectral Hole-Burning and Related Spectroscopies : Science and Applications. Washington, D.C. : Optica Publishing Group, 1994. http://dx.doi.org/10.1364/shbs.1994.wd18.
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Spectral hole-burning is powerful tool for the study of fast relaxation processes (e.g. excited energy transfer - EET, electron transport - e.t.) in photosynthetic systems. Fast e.t. was systematically studied by transient hole-burning (THB) in absorption spectra of reaction centra in purple bacteria and green plants [1]. The THB in fluorescence of PSII particles was described in [2]. Persistent spectral hole-burning (PSHB) enabled to determine the hole-burning mechanism, the EET rate constants, electron-phonon coupling and frequency of protein phonons. The PSHB in fluorescence has been measured in antenna complexes: CP43 and CP47 of PSII [3], B800-850 of purple photosynthetic bacteria [4] and in chlorosomes of green sulphur photosynthetic bacteria [5]. Laser induced hole filling in fluorescence spectra of CP43 of PSII was presented recently in [6]. These data were obtained using wild type organisms. Here, we report an investigation of EET by fluorescence PSHB in photosynthetic antenna using H114Q mutation in the CP47 complex of Synechocystis sp. PCC 6803.
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Ono, Akira, Hirotsugu Kenmotsu, Masakuni Serizawa, Shota Omori, Kazuhisa Nakashima, Kazushige Wakuda, Tateaki Naito et al. « Abstract A61 : Association of clinico-pathological features with epidermal growth factor receptor mutant allele frequency in patients with non-small cell lung cancer ». Dans Abstracts : AACR-NCI-EORTC International Conference : Molecular Targets and Cancer Therapeutics ; November 5-9, 2015 ; Boston, MA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1535-7163.targ-15-a61.
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Jia, Minghan, Ning Liao, Bo Chen, Guochun Zhang, Yulei Wang, Xiaoqing Chen, Liping Guo et al. « Abstract P4-09-11 : PIK3CA somatic alterations in 412 chinese invasive breast cancers : Higher frequency of mutant H1047R detected by next generation sequencing compared to breast cancer in caucasians ». Dans Abstracts : 2019 San Antonio Breast Cancer Symposium ; December 10-14, 2019 ; San Antonio, Texas. American Association for Cancer Research, 2020. http://dx.doi.org/10.1158/1538-7445.sabcs19-p4-09-11.
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Tek, Erhan, et Nizami Duran. « Efficacy of Capsaicin on Cell Adhesion and Invasion of Oral Pathogens ». Dans The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.iii.19.
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Streptococcus pyogenes, Streptococcus mutans, and Candida albicans are important human pathogens and their infections in the mouth, mouth, and throat are important. Prophylaxis against oral and respiratory tract infections is of great importance in terms of both reducing the use of antibiotics and lowering the infection frequency. This study investigated the antimicrobial activity of Capsaicin against S. mutans, C. albicans, and S. pyogenes. Non-cytotoxic concentration of Capsaicin was determined in the Vero cell line by the MTT method. Efficacy studies were performed within these determined non-cytotoxic concentrations. The efficacy of single and different combinations of these three biological components on cell adhesion and invasion. The non-toxic concentration of capsaicin on Vero cells was <1.35 µg/ml. Capsaicin exhibited significant antimicrobial activity against S. pyogenes, S. mutans, and C. albicans. Moreover, capsaicin was statistically significantly effective against host cell adhesion and invasion against S. mutans, S. pyogenes and C. albicans compared to the control group. The results showed that capsaicin is a highly potent antibacterial agent against S. pyogenes, and S. mutans, as well as an important prophylactic agent for fungal infections. As a result, we think that capsaicin is a useful molecule for the provision and maintenance of both respiratory diseases and oral health.
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Stöcklein, Jörg, Daniel Baldin, Wolfgang Müller et Tao Xie. « Virtual Test Environment for Self-Optimizing Systems ». Dans ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12313.
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In our paper we present a virtual test environment for self-optimizing systems based on mutant based testing to validate user tasks of a real-time operating system. This allows the efficient validation of the code coverage of the test cases and therefore helps to detect errors in order to improving the reliability of the system software. Technically we are able to run and test the software on both systems. By writing application software and setting up the virtual test environment properly, we define our test cases. To validate the code coverage for our test cases, we use the approach of mutant based testing. By running this mutated code on our virtual prototype in the virtual test environment, we are able to efficiently validate the code coverage and are able to detect bugs in the application code or detect dead code that is not executed. Finding non-executing code leads to redefinition of our test cases by either changing the test environment or the application code in the case of dead code. We implemented the virtual test environment on top of the third party low cost VR system Unity 3D, which is frequently used in entertainment and education. We demonstrate our concepts by the example of our BeBot robot vehicles. The implementation is based on our self-optimizing real-time operating system ORCOS and we used the tool CERTITUDE(TM) for generating the mutations in our application code. Our BeBot virtual prototype in our virtual test environment implements the same low-level interface to the underlying hardware as the real BeBot. This allows a redirection of commands in ORCOS to either the real or the virtual BeBot in order to provide a VR based platform for early software development as well as ensures comparable conditions under both environments. Our example applies a virtual BeBot that drives through a labyrinth utilizing its IR sensors for navigation. The mutant based testing checks if all situations implemented by the software to navigate through the labyrinth are covered by our tests.
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Brandalero, Marcelo, et Antonio Carlos Beck. « MuTARe : A Multi-Target, Adaptive Reconfigurable Architecture ». Dans XX Simpósio em Sistemas Computacionais de Alto Desempenho. Sociedade Brasileira de Computação - SBC, 2019. http://dx.doi.org/10.5753/wscad_estendido.2019.8706.
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Power consumption, earlier a design constraint only in embedded systems, has become the major driver for architectural optimizations in all domains, from the cloud to the edge. Application-specific accelerators provide a low-power processing solution by efficiently matching the hardware to the application; however, since in many domains the hardware must execute efficiently a broad range of fast-evolving applications, unpredictable at design time and each with distinct resource requirements, alternatives approaches are required. Besides that, the same hardware must also adapt the computational power at run time to the system status and workload sizes. To address these issues, this thesis presents a general-purpose reconfigurable accelerator that can be coupled to a heterogeneous set of cores and supports Dynamic Voltage and Frequency Scaling (DVFS), synergistically combining the techniques for a better match between different applications and hardware when compared to current designs. The resulting architecture, MuTARe, provides a coarse-grained regular and reconfigurable structure which is suitable for automatic acceleration of deployed code through dynamic binary translation. In extension to that, the structure of MuTARe is further leveraged to apply two emerging computing paradigms that can boost the power-efficiency: Near-Threshold Voltage (NTV) computing (while still supporting transparent acceleration) and Approximate Computing (AxC). Compared to a traditional heterogeneous system with DVFS support, the base MuTARe architecture can automatically improve the execution time by up to 1:3×, or adapt to the same task deadline with 1:6× smaller energy consumption, or adapt to the same low energy budget with 2:3× better performance. In NTV mode, MuTARe can transparently save further 30% energy in memory-intensive workloads by operating the combinatorial datapath at half the memory frequency. In AxC mode, MuTARe can further improve power savings by up to 50% by leveraging approximate functional units for arithmetic computations.
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TRUKHACHEV, Vladimir, Sergey OLEYNIK, Nikolay ZLYDNEV et Vitaliy MOROZOV. « SCREENING OF COMPLEX VERTEBRAL MALFORMATION (CVM) AND BOVINE LEUKOCYTE ADHESION DEFICIENCY (BLAD) IN THE AYRSHIRE CATTLE BREED IN THE NORTH CAUCASUS ». Dans RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.142.
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The Ayrshire dairy breed is renowned for producing large quantities of high quality milk and, therefore, is frequently used for crossbreeding. However, various hereditary anomalies caused by gene mutations have been recently recorded in calves produced by some Ayrshire sires. Most of these anomalies were shown to have a recessive inheritance pattern, thus imposing a threat of unpredictable dramatic changes in cattle genotypes under such factors as genetic drift, selection and inbreeding. The purpose of this study was to examine the susceptibility of the Ayrshire cattle bred in the North Caucasus to such hereditary abnormalities as complex vertebral malformation (CVM) and bovine leukocyte adhesion deficiency (BLAD). The investigation was carried out on 16 cows with various phenotype and reproduction disorders that were selected based on a three-year veterinary observation of 440 livestock animals. The target group cows were generally the descendants of Hannulan Yaskiyri, Riihiviidan Urho Errant and O.R. Lihting. The results demonstrated that no animals under study were the carriers of these genetic disorders, which proved the mutant alleles of BLAD and CVM to be absent from the Ayrshire cattle livestock bred in the North Caucasus. Therefore, the sires of these cattle can be successfully used for breeding.
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Santos, Pâmela Gomes, Rosane Nassar Meireles Guerra, Josivan Regis Farias, Simone Batista Muniz et Danielle Cristine Gomes Franco. « AÇÃO ANTIMICROBIANA DAS FLORES DE ANACARDIUM OCCIDENTALE E DO ÁCIDO ELÁGICO PRESENTE NO EXTRATO ». Dans I Congresso Brasileiro de Imunologia On-line. Revista Multidisciplinar em Saúde, 2021. http://dx.doi.org/10.51161/rems/965.
Texte intégralRésumé :
Introdução: As infecções bacterianas têm aumentado significativamente nas últimas décadas, sobretudo aquelas ocasionadas por microrganismos multirresistentes. Assim, o uso de produtos naturais com finalidades terapêuticas surge com alvo de bioprospecção na busca de novos compostos com ação antimicrobiana. Além disso, o uso de insetos, como o Tenebrio molitor como modelo experimental para avaliação in vivo tem sido muito frequente, pois exige menos material em relação aos testes com animais vertebrados. Objetivo: O presente trabalho investigou o efeito citotóxico e ação antimicrobiana do extrato hidroalcoólico das flores de Anacardium occidentale (EHAo) e do ácido elágico. Material e Métodos: Avaliamos a citoxicidade de ácido elágico e do EHAo nas concentrações (1; 5 e 50mg/kg) em Tenebrio molitor. A ação antimicrobiana para Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa e Klebsiella pneumoniae e a toxicidade do ácido elágico, foi avaliada por microdiluição, segundo a norma M7-A6 do manual da Clinical and Laboratory Standards Institute – CLSI. Foi determinada a Concentração Bactericida Mínima (CBM) e concentração inibitória mínima (CIM), em culturas de 24 horas, incubadas à 37ºC. Resultados: No ensaio de citotoxidade aguda se verificou que nenhuma das concentrações usados foram tóxicas, pois não ocorreram óbitos e nem nenhuma anormalia morfológica nas larvas de Tenebrio molitor. Os testes de concentração inibitória mínima (CIM) de concentração bactericida mínima (CBM) mostraram que o EHAo apresentou ação bactericida para Enterococcus faecalis em todas as concentrações testadas. Para Staphylococcus aureus os resultados mostraram ação bactericida para as maiores concentrações e bacteriostática para a menor diluição. O ácido elágico teve ação bactericida apenas para Enterococcus faecalis. Para as bactérias Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa e Klebsiella pneumoniae as concentrações de EHAo e ácido elágico testadas não foram inibitórias. Conclusões: Os resultados mostraram baixa toxicidade tanto para o EHAo como para o ácido elágico e ainda, que o extrato apresentou melhor efeito antimicrobiano do que o ácido elágico, para Enterococcus faecalis e Staphylococcus aureus.
Rapports d'organisations sur le sujet "Mutant frequency"
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Jett, J. Pre-thymic somatic mutation leads to high mutant frequency at hypoxanthine-guanine phosphoribosyltransferase gene. Office of Scientific and Technical Information (OSTI), décembre 1994. http://dx.doi.org/10.2172/98640.
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Splitter, Gary A., Menachem Banai et Jerome S. Harms. Brucella second messenger coordinates stages of infection. United States Department of Agriculture, janvier 2011. http://dx.doi.org/10.32747/2011.7699864.bard.
Texte intégralRésumé :
Aim 1: To determine levels of this second messenger in: a) B. melitensiscyclic-dimericguanosinemonophosphate-regulating mutants (BMEI1448, BMEI1453, and BMEI1520), and b) B. melitensis16M (wild type) and mutant infections of macrophages and immune competent mice. (US lab primary) Aim 2: To determine proteomic differences between Brucelladeletion mutants BMEI1453 (high cyclic-dimericguanosinemonophosphate, chronic persistent state) and BMEI1520 (low cyclicdimericguanosinemonophosphate, acute virulent state) compared to wild type B. melitensisto identify the role of this second messenger in establishing the two polar states of brucellosis. (US lab primary with synergistic assistance from the Israel lab Aim 3: Determine the level of Brucellacyclic-dimericguanosinemonophosphate and transcriptional expression from naturally infected placenta. (Israel lab primary with synergistic assistance from the US lab). B. Background Brucellaspecies are Gram-negative, facultative intracellular bacterial pathogens that cause brucellosis, the most prevalent zoonosis worldwide. Brucellosis is characterized by increased abortion, weak offspring, and decreased milk production in animals. Humans are infected with Brucellaby consuming contaminated milk products or via inhalation of aerosolized bacteria from occupational hazards. Chronic human infections can result in complications such as liver damage, orchitis, endocarditis, and arthritis. Brucellaspp. have the ability to infect both professional and non-professional phagocytes. Because of this, Brucellaencounter varied environments both throughout the body and within a cell and must adapt accordingly. To date, few virulence factors have been identified in B. melitensisand even less is known about how these virulence factors are regulated. Subsequently, little is known about how Brucellaadapt to its rapidly changing environments, and how it alternates between acute and chronic virulence. Our studies suggest that decreased concentrations of cyclic dimericguanosinemonophosphate (c-di-GMP) lead to an acute virulent state and increased concentrations of c-di-GMP lead to persistent, chronic state of B. melitensisin a mouse model of infection. We hypothesize that B. melitensisuses c-di-GMP to transition from the chronic state of an infected host to the acute, virulent stage of infection in the placenta where the bacteria prepare to infect a new host. Studies on environmental pathogens such as Vibrio choleraeand Pseudomonas aeruginosasupport a mechanism where changes in c-di-GMP levels cause the bacterium to alternate between virulent and chronic states. Little work exists on understanding the role of c-di-GMP in dangerous intracellular pathogens, like Brucellathat is a frequent pathogen in Israeli domestic animals and U.S. elk and bison. Brucellamust carefully regulate virulence factors during infection of a host to ensure proper expression at appropriate times in response to host cues. Recently, the novel secondary signaling molecule c-di-GMP has been identified as a major component of bacterial regulation and we have identified c-di-GMP as an important signaling factor in B. melitensishost adaptation. C. Major conclusions, solutions, achievements 1. The B. melitensis1453 deletion mutant has increased c-di-GMP, while the 1520 deletion mutant has decreased c-di-GMP. 2. Both mutants grow similarly in in vitro cultures; however, the 1453 mutant has a microcolony phenotype both in vitro and in vivo 3. The 1453 mutant has increased crystal violet staining suggesting biofilm formation. 4. Scanning electron microscopy revealed an abnormal coccus appearance with in increased cell area. 5. Proteomic analysis revealed the 1453 mutant possessed increased production of proteins involved in cell wall processes, cell division, and the Type IV secretion system, and a decrease in proteins involved in amino acid transport/metabolism, carbohydrate metabolism, fatty acid production, and iron acquisition suggesting less preparedness for intracellular survival. 6. RNAseq analysis of bone marrow derived macrophages infected with the mutants revealed the host immune response is greatly reduced with the 1453 mutant infection. These findings support that microlocalization of proteins involved in c-di-GMP homeostasis serve a second messenger to B. melitensisregulating functions of the bacteria during infection of the host.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion et Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, octobre 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Texte intégralRésumé :
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
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Or, Etti, Tai-Ping Sun, Amnon Lichter et Avichai Perl. Characterization and Manipulation of the Primary Components in Gibberellin Signaling in the Grape Berry. United States Department of Agriculture, janvier 2010. http://dx.doi.org/10.32747/2010.7592649.bard.
Texte intégralRésumé :
Seedless cultivars dominate the table grape industry. In these cultivars it is mandatory to apply gibberellin (GA) to stimulate berry development to a commercially acceptable size. These cultivars differ in their sensitivity to GA application, and it frequently results in adverse effects such as decreased bud fertility and increased fruit drop. Our long term goals are to (1) understand the molecular basis for the differential sensitivity and identify markers for selection of sensitive cultivars (2) to develop new strategies for targeted manipulation of the grape berry response to GA that will eliminate the need in GA application and the undesirable effects of GA on the vine, while maintaining its desirable effects on the berry. Both strategies are expected to reduce production cost and meet growing consumer demand for reduced use of chemicals. This approach relies on a comprehensive characterization of the central components in the GA signaling cascade in the berry. Several key components in the GA signaling pathway were identified in Arabidopsis and rice, including the GA receptors, GID1s, and a family of DELLA proteins that are the major negative regulators of the GA response. GA activates its response pathway by binding to GID1s, which then target DELLAs for degradation via interaction with SLY, a DELLA specific F-box protein. In grape, only one DELLA gene was characterized prior to this study, which plays a major role in inhibiting GA-promoted stem growth and GA-repressed floral induction but it does not regulate fruit growth. Therefore, we speculated that other DELLA family member(s) may control GA responses in berry, and their identification and manipulation may result in GA-independent berry growth. In the current study we isolated two additional VvDELLA family members, two VvGID1 genes and two VvSLY genes. Arabidopsis anti-AtRGA polyclonal antibodies recognized all three purified VvDELLA proteins, but its interaction with VvDELLA3 was weaker. Overexpression of the VvDELLAs, the VvGID1s, and the VvSLYs in the Arabidopsis mutants ga1-3/rga-24, gid1a-2/1c-2 and sly1-10, respectively, rescued the various mutant phenotypes. In vitro GAdependent physical interaction was shown between the VvDELLAs and the VvGID1s, and GAindependent interaction was shown between the VvDELLAs and VvSLYs. Interestingly, VvDELLA3 did not interact with VvGID1b. Together, the results indicate that the identified grape homologs serve as functional DELLA repressors, receptors and DELLA-interacting F-box proteins. Expression analyses revealed that (1) VvDELLA2 was expressed in all the analyzed tissues and was the most abundant (2) VvDELLA1 was low expressed in berries, confirming former study (3) Except in carpels and very young berries, VvDELLA3 levels were the lowest in most tissues. (4) Expression of both VvGID1s was detected in all the grape tissues, but VvGID1b transcript levels were significantly higher than VvGID1a. (5) In general, both VvDELLAs and VvGID1s transcripts levels increased as tissues aged. Unfertilized and recently fertilized carpels did not follow this trend, suggesting different regulatory mechanism of GA signaling in these stages. Characterization of the response to GA of various organs in three seedless cultivars revealed differential response of the berries and rachis. Interestingly, VvDELLA3 transcript levels in the GA-unresponsive berries of cv. Spring blush were significantly higher compared to their levels in the highly responsive berries of cv. Black finger. Assuming that VvDELLA2 and VvDELLA3 are regulating berry size, constructs carrying potential dominant mutations in each gene were created. Furthermore, constitutive silencing of these genes by mIR is underway, to reveal the effect of each gene on the berry phenotype.
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Splitter, Gary, Zeev Trainin et Yacov Brenner. Lymphocyte Response to Genetically Engineered Bovine Leukemia Virus Proteins in Persistently Lymphocytic Cattle from Israel and the U.S. United States Department of Agriculture, juillet 1995. http://dx.doi.org/10.32747/1995.7570556.bard.
Texte intégralRésumé :
The goal of this proposal was to identify proteins of BLV recognized by lymphocyte subpopulations and determine the contribution of these proteins to viral pathogenesis. Our hypothesis was that BLV pathogenesis is governed by the T-cell response and that the immune system likely plays an important role in controlling the utcome of infection. Our studies presented in ths final report demonstrate that T cell competency declines with advancing stages of infection. Dramatic differences were observed in lymphocyte proliferation to recombinant proteins encoded by BLV gag (p12, p15, and p24) and env (gp30 and gp15) genes in different disease stages. Because retroviruses are known to mutate frequently, examinatin of infected cattle from both Israel and the United States will likely detect variability in the immune response. This combined research approach provides the first opportunity to selectively address the importance of T-cell proliferation to BLV proteins and cytokines produced during different stages of BLV infection. Lack of this information regarding BLV infection has hindered understanding lympocyte regulation of BLV pathogenesis. We have developed the essential reagents necessary to determine the prominence of different lymphocyte subpopulations and cytokines produced during the different disease stages within the natural host. We found that type 1 cytokines (IL-2 and IFN-g) increased in PBMCs from animals in early disease, and decreasd in PBMCs from animals in late disease stages of BLV infection, while IL-10, increased with disease progression. Recently, a dichotomy between IL-12 and IL-10 has emerged in regards to progression of a variety of diseases. IL-12 activates type 1 cytokine production and has an antagonistic effect on type 2 cytokines. Here, using quantitative competitive PCR, we show that peripheral blood mononuclear cells from bovine leukemia virus infected animals in the alymphocytotic disease stage express increased amount of IL-12 p40 mRNA. In contrast, IL-12 p40 mRNA expression by PL animals was significantly decreased compared to normal and alymphocytotic animals. To examine the functions of these cytokines on BLV expression, BLV tax and pol mRNA expression and p24 protein production were quantified by competitive PCR, and by immunoblotting, respectively. IL-10 inhibited BLV tax and pol mRNA expression by BLV-infected PBMCs. In addition, we determined that macrophages secret soluble factor(s) that activate BLV expression, and that secretion of the soluble factor(s) could be inhibited by IL-10. In contrast, IL-2 increased BLV tax and pol mRNA, and p24 protein production. These findings suggest that macrophages have a key role in regulating BLV expression, and IL-10 produced by BLV-infected animals in late disease stages may serve to control BLV expression, while IL-2 in the early stage of disease may activate BLV expression. PGE2 is an important immune regulator produced only by macrophages, and is known to facilitate HIV replication. We hypothesized that PGE2 may regulate BLV expression. Here, we show that cyclooxygenase-2 (COX-2) mRNA expression was decreased in PBMCs treated with IL-10, while IL-2 enhanced COX-2 mRNA expression. In contrast, addition of PGE2 stimulated BLV tax and pol mRNA expression. In addition, the specific COX-2 inhibitor, NS-398, inhibited BLV expression, while addition of PGE2 increased BLV tax expression regardless of NS-398. These findings suggest that macrophage derived cyclooxygenase -2 products, such as PGE2, may regulate virus expression and disease rogression in BLV infection, and that cytokines (IL-2 and IL-10) may regulate BLV expression through PGE2 production.