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Dominant Genotype (dominant + genotype)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Compound KIR - HLA genotype analyses in the Iranian population by a novel PCR,SSP assay

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2010
N. Tajik
Summary Natural killer (NK) cells eliminate infected and transformed cells while still are self-tolerant. Interactions of the independently segregating Killer cell immunoglobulin-like receptors (KIR) and human leucocyte antigens (HLA) loci play a critical role in NK cell regulation. Different compound KIR-HLA genotypes can impart different thresholds of activation to the NK-cell repertoire and such genotypic variation has been found to confer altered risk in a number of human diseases including viral infections, autoimmune disorders, reproduction abnormalities and cancers. In this study, we presented a novel combined KIR-HLA polymerase chain reaction,sequence-specific primers genotyping assay for simultaneous determination of KIR genes and their three major HLA class I ligand groups (C1, C2, and Bw4). Moreover, known inhibitory and activating KIR + HLA (iKIR + HLA: 2DL2/3 + C1, 2DL1 + C2, 3DL1 + Bw4; and aKIR + HLA: 2DS2 + C1, 2DS1 + C2, 3DS1 + Bw4) combinations as well as co-inheritance of aKIR genes and iKIR + HLA pairs were analysed in a total of 200 unrelated healthy Iranian individuals. All tested subjects had at least one of the three iKIR + HLA pairs and the frequencies of various inhibitory combinations in the study group were: 31.5%, three iKIR + HLA pairs, 53.5%, two iKIR + HLA pairs, and 15%, 0ne iKIR + HLA pair. Furthermore, we revealed that majority of Iranians (69%) carry compound genotypes with greater number of inhibitory pairings than activating combinations (iKIR + HLA > aKIR + HLA). Conversely, iKIR + HLA < aKIR (45%) was dominant genotype in the study group. We conclude that selective evolutionary pressure has propensity to maintain KIR-HLA genotypes with more inhibitory combinations to guarantee self-tolerance. In contrast, existence of activating KIR genes without normal endogenous ligands, potentially arms the NK population for competent immunosurveillance and stronger defense against infections. [source]

Analysis of drug resistance and virulence-factor genotype of Irish Helicobacter pylori strains: is there any relationship between resistance to metronidazole and cagA status?

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 7 2009
I. TANEIKE
Summary Background,Helicobacter pylori infection is eradicated with antimicrobial agents and drug-resistant strains make successful treatment difficult. Geographical variations in virulence-factor genotype also exist. Aim, To evaluate prevalence of drug resistance and virulence-factor genotype in Irish H. pylori strains and to investigate if there is any relationship between drug resistance and genotype. Methods,Helicobacter pylori strains isolated from 103 patients were examined. Antimicrobial susceptibilities were tested by Etest. The virulence-factor genotypes were determined using PCR. Frequencies of spontaneous metronidazole-resistance were measured in vitro. Results, Metronidazole resistance was present in 37.9% of strains examined. 16.5% of strains were clarithromycin-resistant and resistance to both agents observed was found in 12.6% of strains. 68% of strains were cagA+. The dominant vacA type was s1/m2, followed by s1/m1 and s2/m2. The metronidazole resistance rate in cagA, group was significantly higher than in cagA+ (P = 0.0089). Spontaneous resistance to metronidazole in cagA, occurred in higher frequency when compared with cagA+. Conclusions,cagA+ and vacAs1/m2 type was the dominant genotype in Irish H. pylori strains. Significant rates of metronidazole resistance were observed in cagA, group. cagA, strains tend to acquire metronidazole resistance in vitro. Absence of cagA might be a risk factor in development of metronidazole resistance. [source]

Characterization of Ascochyta isolates and susceptibility of pea cultivars to the ascochyta disease complex in Alberta

PLANT PATHOLOGY, Issue 5 2000
H. Wang
The relative virulence of 109 Ascochyta isolates collected from pea fields in Alberta from 1996 to 1998 were evaluated on 10-day-old seedlings by the excised leaf-assay technique. Twenty-eight isolates were avirulent, while the others produced lesions of various sizes on pea leaves. DNA samples from 86 isolates were amplified by the RAPD technique using PCR with single primers. One dominant genotype of Ascochyta pisi was identified throughout Alberta, but variations in virulence were not clearly differentiated by the RAPD technique. Five Ascochyta isolates, four virulent and one avirulent, were used to assess the susceptibility of 20 field pea cultivars available in Alberta, including 13 yellow types and seven green types. Based on symptom development, the yellow-type cultivars Swing, Eiffel and Delta, and the green-type cultivar Orb, were the most susceptible. Of yellow-type cultivars, Voyageur, Carneval and Montana were most resistant to Ascochyta infection. [source]

Intraspecific diversity and dominant genotypes resist plant invasions

ECOLOGY LETTERS, Issue 1 2008
Gregory M. Crutsinger
Abstract Numerous studies have asked whether communities with many species deter invasions more so than do species-poor communities or whether dominant species deter invasion by colonizing species. However, little is known about whether high intraspecific diversity can deter biological invasions or whether particular genotypes might deter invasions. In this study, we present experimental evidence that intraspecific diversity and particular genotypes of tall goldenrod, Solidago altissima, can act as a barrier to colonization by new species. We found that biomass of colonizing species was negatively correlated with genotypic diversity, and particular genotypes affected the richness, cover, and biomass of colonizing species. Stem density of S. altissima increased with genotypic diversity and varied among genotypes, suggesting that stem density is a key mechanism in limiting colonization dynamics in this system. Our results indicate that the loss of intraspecific diversity within a dominant plant species can increase susceptibility to plant invasions. [source]