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Query: UMLS:C0012872 (DNA marker)
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In cultivated beet no useful level of resistance of the beet cyst nematode (BCN) Heterodera schachtii Schm. has been found, unlike the situation in wild species of the section Procumbentes. Stable introgression of resistance genes from the wild species into Beta vulgaris has not been achieved, but resistant monosomic additions (2n = 18 + 1), diploids of B. vulgaris with an extra alien chromosome carrying the resistance locus, have been obtained. Here we describe a new series of resistant monosomic fragment addition material of B. patellaris chromosome 1 (pat-1). We further describe the cloning of a single-copy DNA marker that specifically hybridizes with a monosomic addition fragment of approximately 8 Mb (AN5-90) carrying the BCN resistance locus. This marker and another fragment-specific, single-copy DNA marker probably flank the BCN locus on the addition fragment present in the AN5-203 material, which is approximately 19 Mb in size. Furthermore, several specific repetitive DNA markers have been isolated, one of which hybridizes to AN5-90 and also to DNA from a smaller DNA segment of Beta procumbens, present in line B883, carrying a BCN resistance locus introgressed into the B. vulgaris genome. This suggests that the specific repetitive marker is closely linked to the BCN locus.
Mol Gen Genet 1992 Nov
PMID:Isolation of DNA markers linked to a beet cyst nematode resistance locus in Beta patellaris and Beta procumbens. 146 14

We have investigated the ATP-induced permeabilization of rat peritoneal mast cells using three different techniques: (a) by measuring uptake of fluorescent membrane and DNA marker dyes, (b) by voltage-clamp measurements using the patch-clamp technique, and (c) by measurements of exocytosis in response to entry of Ca2+ and GTP gamma S into permeabilized cells. In the absence of divalent cations cells become highly permeable at ATP concentrations as low as 3 microM. In normal saline containing 1 mM MgCl2 and 2 mM CaCl2, dye uptake and electric conductance are detectable at 100 microM ATP corresponding to 4 microM ATP4-. The permeabilization is half-maximal at an ATP4- concentration of 5-20 microM with a Hill coefficient near 2. The ATP-induced whole-cell conductance at saturating ATP concentrations was 35-70 nS, exhibiting only weak cation selectivity. The activation is very fast with a time constant less than or equal to 65 ms. Pores which are large enough to allow for permeation of substances of 300-900 D are expected to have a unit conductance of approximately 200-400 pS. However, in whole cells as well as outside-out patches, discrete openings and closings of channels could not be observed at a resolution of approximately 40 pS and the single-channel conductance obtained from noise analysis is approximately 2-10 pS. Entry of Ca2+ into cells permeabilized with ATP stimulates exocytosis at low but not at high ATP concentrations indicating loss of an essential intracellular component or components at a high degree of permeabilization. This inactivation is removed when GTP gamma S is provided in the medium and this leads to enhanced exocytosis. The enhancement only occurs at high ATP concentrations. These results strongly suggest that the ATP-induced pores are of variable size and can increase or decrease by very small units.
J Gen Physiol 1990 Mar
PMID:ATP-induced pore formation in the plasma membrane of rat peritoneal mast cells. 218 68

Azotobacter vinelandii OP which had been naturally induced to competence by growth in iron- and molybdenum-limited medium was transformed with the broad-host-range cloning vector pKT210. However, the transformation frequency at nearly saturating levels of DNA was 1000-fold lower for pKT210 than for a single chromosomal DNA marker (nif+). Plasmid- and chromosomal-DNA-mediated transformation events were competitive, magnesium-dependent, 42 degrees C-sensitive processes specific to double-stranded DNA, suggesting a common mechanism of DNA binding and uptake. The low frequency of plasmid transformation was not related to restriction of transforming DNA or to the growth period allowed for phenotypic expression. Covalently-closed-circular and open-circular forms of pKT210 transformed cells equally well whereas EcoRI- or HindIII-linearized pKT210 transformed cells with two to three times greater efficiency. Genetic transformation was enhanced 10- to 50-fold when pKT210 contained an insert fragment of A. vinelandii nif DNA, indicating that A. vinelandii possessed a homology-facilitated transformation system. However, all transformants failed to maintain the plasmid-encoded antibiotic resistance determinants, and extrachromosomal plasmid DNA was not recovered from these cells. Flush-ended pKT210 was not active in transformation; however, competent cells were transformed to Nif+ by HincII-digested plasmid DNA containing the cloned A. vinelandii nif-10 marker.
J Gen Microbiol 1987 Aug
PMID:Plasmid transformation of Azotobacter vinelandii OP. 344 52

A colony-level phenotype was used to map the major sex determination locus (designated X) in the honey bee (Apis mellifera). Individual queen bees (reproductive females) were mated to single drones (fertile males) by instrumental insemination. Haploid drone progeny of an F1 queen were each backcrossed to daughter queens from one of the parental lines. Ninety-eight of the resulting colonies containing back-cross progeny were evaluated for the trait 'low brood-viability' resulting from the production of diploid drones that were homozygous at X. DNA samples from the haploid drone fathers of these colonies were used individually in polymerase chain reactions (PCR) with 10-base primers. These reactions generated random amplified polymorphic DNA (RAPD) markers that were analyzed for cosegregation with the colony-level phenotype. One RAPD marker allele was shared by 22 of 25 drones that fathered low brood-viability colonies. The RAPD marker fragment was cloned and partially sequenced. Two primers were designed that define a sequence-tagged site (STS) for this locus. The primers amplified DNA marker fragments that cosegregated with the original RAPD marker. In order to more precisely estimate the linkage between X and the STS locus, another group of bees consisting of progeny from one of the low-brood viability colonies was used in segregation analysis. Four diploid drones and 181 of their diploid sisters (workers, nonfertile females) were tested for segregation of the RAPD and STS markers. The cosegregating RAPD and STS markers were codominant due to the occurrence of fragment-length alleles. The four diploid drones were homozygous for these markers but only three of the 181 workers were homozygotes (recombinants). Therefore the distance between X and the STS locus was estimated at 1.6 cM. An additional linked marker was found that was 6.6 cM from the STS locus.
Mol Gen Genet 1994 Sep 01
PMID:Linkage analysis of sex determination in the honey bee (Apis mellifera). 807 78

A size-selected genomic library comprising 280,000 colonies and representing approximately 18% of the chickpea genome, was screened for (GA)n, (GAA)n and (TAA)n microsatellite-containing clones, of which 389 were sequenced. The majority (approximately 75%) contained perfect repeats; interrupted, interrupted compound and compound repeats were only present in 6%-9% of cases. (TAA)-microsatellites contained the longest repeats, with unit numbers from 9 to 131. For 218 loci primers could be designed and used for the detection of microsatellite length polymorphisms in six chickpea breeding cultivars, as well as in C. reticulatum and C. echinospermum, wild, intercrossable relatives of chickpea. A total of 174 primer pairs gave interpretable banding patterns, 137 (79%) of which revealed at least two alleles on native polyacrylamide gels. A total of 120 sequence-tagged microsatellite site (STMS) markers were genetically mapped in 90 recombinant inbred lines from an inter-species cross between C. reticulatum and the chickpea cultivar ICC 4958. Markers could be arranged in 11 linkage groups (at a LOD score of 4) covering 613 cM. Clustering as well as random distribution of loci was observed. Segregation of 46 markers (39%) deviated significantly (P > or = 0.05) from the expected 1:1 ratio. The majority of these loci (73%) were located in three distinct regions of the genome. The present STMS marker map represents the most advanced co-dominant DNA marker map of the chickpea genome.
Mol Gen Genet 1999 Aug
PMID:Characterization and mapping of sequence-tagged microsatellite sites in the chickpea (Cicer arietinum L.) genome. 1050 40

We recruited 560 unrelated patients with ischemic stroke and 153 unrelated controls to undertake a genetic analysis for association between the NOS3 gene and ischemic stroke. All the subjects were Chinese of Han descent. Because the NOS3 gene spans about 21 kb of DNA and contains 26 exons, we selected a single nucleotide polymorphism (SNP) rs3918181, an A to G base change located in intron 14 of the gene, as a DNA marker. PCR-based restriction fragment length polymorphism analysis was applied to genotype rs3918181 (RsaI site). The chi-square (chi(2)) goodness-of-fit test showed that the genotypic distributions of the marker were not deviated from Hardy-Weinberg equilibrium in both the patient group (chi(2) = 0.166, p = 0.684) and the control group (chi(2) = 0.421, p = 0.517). The cocaphase analysis showed allelic association of rs3918181 with ischemic stroke in males (chi(2) = 4.04, p = 0.044, OR = 1.43, 95% CI 1.01 approximately 2.02) and frequency of allele A was significantly higher in male patients than male control subjects. The chi(2) test revealed genotypic association between rs3918181 and ischemic stroke in males (chi(2) = 4.26, df = 1, p = 0.039, OR = 1.61, 95% CI 1.02 approximately 2.53) but not in females. The present work suggests that rs3918181 is associated with ischemic stroke in male patients. This finding gives further evidence in support of the eNOS association with ischemic stroke in the Chinese population.
Int J Gen Med 2008 Nov 30
PMID:A genetic study of the NOS3 gene for ischemic stroke in a Chinese population. 2042 8