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Sample records for pm3 resistance locus

  1. Unlocking wheat genetic resources for the molecular identification of previously undescribed functional alleles at the Pm3 resistance locus

    PubMed Central

    Bhullar, Navreet K.; Street, Kenneth; Mackay, Michael; Yahiaoui, Nabila; Keller, Beat

    2009-01-01

    The continuous improvement of crop plants is essential for agriculture in the coming decades and relies on the use of genetic variability through breeding. However, domestication and modern breeding have reduced diversity in the crop germplasm. Global gene banks conserve diversity, but these resources remain underexplored owing to a lack of efficient strategies to isolate important alleles. Here we describe a large-scale allele-mining project at the molecular level. We first selected a set of 1,320 bread wheat landraces from a database of 16,089 accessions, using the focused identification of germplasm strategy. On the basis of a hierarchical selection procedure on this set, we then isolated 7 resistance alleles of the powdery mildew resistance gene Pm3, doubling the known functional allelic diversity at this locus. This targeted approach for molecular utilization of gene bank accessions reveals landraces as a rich resource of new functional alleles. This strategy can be implemented for other studies on the molecular diversity of agriculturally important genes, as well as for molecular breeding. PMID:19470492

  2. Unlocking wheat genetic resources for the molecular identification of previously undescribed functional alleles at the Pm3 resistance locus.

    PubMed

    Bhullar, Navreet K; Street, Kenneth; Mackay, Michael; Yahiaoui, Nabila; Keller, Beat

    2009-06-01

    The continuous improvement of crop plants is essential for agriculture in the coming decades and relies on the use of genetic variability through breeding. However, domestication and modern breeding have reduced diversity in the crop germplasm. Global gene banks conserve diversity, but these resources remain underexplored owing to a lack of efficient strategies to isolate important alleles. Here we describe a large-scale allele-mining project at the molecular level. We first selected a set of 1,320 bread wheat landraces from a database of 16,089 accessions, using the focused identification of germplasm strategy. On the basis of a hierarchical selection procedure on this set, we then isolated 7 resistance alleles of the powdery mildew resistance gene Pm3, doubling the known functional allelic diversity at this locus. This targeted approach for molecular utilization of gene bank accessions reveals landraces as a rich resource of new functional alleles. This strategy can be implemented for other studies on the molecular diversity of agriculturally important genes, as well as for molecular breeding. PMID:19470492

  3. Rye-derived powdery mildew resistance gene Pm8 in wheat is suppressed by the Pm3 locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic suppression of disease resistance is occasionally observed in hexaploid wheat or in its interspecific crosses. The phenotypic effects of genes moved to wheat from relatives with lower ploidy are often smaller than in the original sources, suggesting the presence of modifiers or partial inhib...

  4. Multiple Avirulence Loci and Allele-Specific Effector Recognition Control the Pm3 Race-Specific Resistance of Wheat to Powdery Mildew[OPEN

    PubMed Central

    Roffler, Stefan; Stirnweis, Daniel; Treier, Georges; Herren, Gerhard; Korol, Abraham B.; Wicker, Thomas

    2015-01-01

    In cereals, several mildew resistance genes occur as large allelic series; for example, in wheat (Triticum aestivum and Triticum turgidum), 17 functional Pm3 alleles confer agronomically important race-specific resistance to powdery mildew (Blumeria graminis). The molecular basis of race specificity has been characterized in wheat, but little is known about the corresponding avirulence genes in powdery mildew. Here, we dissected the genetics of avirulence for six Pm3 alleles and found that three major Avr loci affect avirulence, with a common locus_1 involved in all AvrPm3-Pm3 interactions. We cloned the effector gene AvrPm3a2/f2 from locus_2, which is recognized by the Pm3a and Pm3f alleles. Induction of a Pm3 allele-dependent hypersensitive response in transient assays in Nicotiana benthamiana and in wheat demonstrated specificity. Gene expression analysis of Bcg1 (encoded by locus_1) and AvrPm3 a2/f2 revealed significant differences between isolates, indicating that in addition to protein polymorphisms, expression levels play a role in avirulence. We propose a model for race specificity involving three components: an allele-specific avirulence effector, a resistance gene allele, and a pathogen-encoded suppressor of avirulence. Thus, whereas a genetically simple allelic series controls specificity in the plant host, recognition on the pathogen side is more complex, allowing flexible evolutionary responses and adaptation to resistance genes. PMID:26452600

  5. Wheat gene bank accessions as a source of new alleles of the powdery mildew resistance gene Pm3: a large scale allele mining project

    PubMed Central

    2010-01-01

    Background In the last hundred years, the development of improved wheat cultivars has led to the replacement of landraces and traditional varieties by modern cultivars. This has resulted in a decline in the genetic diversity of agriculturally used wheat. However, the diversity lost in the elite material is somewhat preserved in crop gene banks. Therefore, the gene bank accessions provide the basis for genetic improvement of crops for specific traits and and represent rich sources of novel allelic variation. Results We have undertaken large scale molecular allele mining to isolate new alleles of the powdery mildew resistance gene Pm3 from wheat gene bank accessions. The search for new Pm3 alleles was carried out on a geographically diverse set of 733 wheat accessions originating from 20 countries. Pm3 specific molecular tools as well as classical pathogenicity tests were used to characterize the accessions. Two new functional Pm3 alleles were identified out of the eight newly cloned Pm3 sequences. These new resistance alleles were isolated from accessions from China and Nepal. Thus, the repertoire of functional Pm3 alleles now includes 17 genes, making it one of the largest allelic series of plant resistance genes. The combined information on resistant and susceptible Pm3 sequences will allow to study molecular function and specificity of functional Pm3 alleles. Conclusions This study demonstrates that molecular allele mining on geographically defined accessions is a useful strategy to rapidly characterize the diversity of gene bank accessions at a specific genetic locus of agronomical importance. The identified wheat accessions with new resistance specificities can be used for marker-assisted transfer of the Pm3 alleles to modern wheat lines. PMID:20470444

  6. Molecular cloning, functional verification, and evolution of TmPm3, the powdery mildew resistance gene of Triticum monococcum L.

    PubMed

    Zhao, C Z; Li, Y H; Dong, H T; Geng, M M; Liu, W H; Li, F; Ni, Z F; Wang, X J; Xie, C J; Sun, Q X

    2016-01-01

    Powdery mildew (Pm) is one of the most harmful diseases in wheat. Three Pm-resistance genes, Pm3, Pm21, and Pm8, have been cloned but most Pm3/Pm8 alleles have lost their resistance to Pm in hexaploid wheat. In this study, a new Pm3 homolog gene (TmPm3) was isolated from Triticum monococcum L. using a homology-based cloning strategy, being the first report of a functional Pm3 homolog gene from a diploid wheat species. The transient expression of TmPm3 in leaf epidermal cells showed that over-expressed TmPm3 could significantly inhibit the penetration of Blumeria graminis f. sp tritici conidia spores and the formation of haustoria. Sequence analysis of Pm3 alleles shed new light on the evolution of Pm3 genes, providing a better understanding of the molecular basis of disease resistance. This study also suggested that homology-based cloning of resistance genes is a feasible method for the isolation of functional resistance genes from wheat germplasm. PMID:27173250

  7. Identification of Pm8 Suppressor at Pm3 Locus in Soft 1 Red Winter Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 1BL.1RS wheat-rye translocation possesses the Pm8, Yr9, Lr26, and Sr31 genes for resistance to several major fungal pathogens of small grains. However, not all wheat cultivars with the 1RS translocation are resistant to Pm8-avirulent isolates of Blumeria graminis f. sp. tritici (Bgt), the causal...

  8. The barley Frost resistance-H2 locus.

    PubMed

    Pasquariello, Marianna; Barabaschi, Delfina; Himmelbach, Axel; Steuernagel, Burkhard; Ariyadasa, Ruvini; Stein, Nils; Gandolfi, Francesco; Tenedini, Elena; Bernardis, Isabella; Tagliafico, Enrico; Pecchioni, Nicola; Francia, Enrico

    2014-03-01

    Frost resistance-H2 (Fr-H2) is a major QTL affecting freezing tolerance in barley, yet its molecular basis is still not clearly understood. To gain a better insight into the structural characterization of the locus, a high-resolution linkage map developed from the Nure × Tremois cross was initially implemented to map 13 loci which divided the 0.602 cM total genetic distance into ten recombination segments. A PCR-based screening was then applied to identify positive bacterial artificial chromosome (BAC) clones from two genomic libraries of the reference genotype Morex. Twenty-six overlapping BACs from the integrated physical-genetic map were 454 sequenced. Reads assembled in contigs were subsequently ordered, aligned and manually curated in 42 scaffolds. In a total of 1.47 Mbp, 58 protein-coding sequences were identified, 33 of which classified according to similarity with sequences in public databases. As three complete barley C-repeat Binding Factors (HvCBF) genes were newly identified, the locus contained13 full-length HvCBFs, four Related to AP2 Triticeae (RAPT) genes, and at least five CBF pseudogenes. The final overall assembly of Fr-H2 includes more than 90 % of target region: all genes were identified along the locus, and a general survey of Repetitive Elements obtained. We believe that this gold-standard sequence for the Morex Fr-H2 will be a useful genomic tool for structural and evolutionary comparisons with Fr-H2 in winter-hardy cultivars along with Fr-2 of other Triticeae crops. PMID:24442711

  9. Mutations in the Plasmodium falciparum Cyclic Amine Resistance Locus (PfCARL) Confer Multidrug Resistance

    PubMed Central

    LaMonte, Gregory; Lim, Michelle Yi-Xiu; Wree, Melanie; Reimer, Christin; Nachon, Marie; Corey, Victoria; Gedeck, Peter; Plouffe, David; Du, Alan; Figueroa, Nelissa; Yeung, Bryan; Winzeler, Elizabeth A.

    2016-01-01

    ABSTRACT Mutations in the Plasmodium falciparum cyclic amine resistance locus (PfCARL) are associated with parasite resistance to the imidazolopiperazines, a potent class of novel antimalarial compounds that display both prophylactic and transmission-blocking activity, in addition to activity against blood-stage parasites. Here, we show that pfcarl encodes a protein, with a predicted molecular weight of 153 kDa, that localizes to the cis-Golgi apparatus of the parasite in both asexual and sexual blood stages. Utilizing clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene introduction of 5 variants (L830V, S1076N/I, V1103L, and I1139K), we demonstrate that mutations in pfcarl are sufficient to generate resistance against the imidazolopiperazines in both asexual and sexual blood-stage parasites. We further determined that the mutant PfCARL protein confers resistance to several structurally unrelated compounds. These data suggest that PfCARL modulates the levels of small-molecule inhibitors that affect Golgi-related processes, such as protein sorting or membrane trafficking, and is therefore an important mechanism of resistance in malaria parasites. PMID:27381290

  10. Tomato mutants altered in bacterial disease resistance provide evidence for a new locus controlling pathogen recognition.

    PubMed Central

    Salmeron, J M; Barker, S J; Carland, F M; Mehta, A Y; Staskawicz, B J

    1994-01-01

    We have employed a genetic approach to study the resistance of tomato to the phytopathogenic bacterium Pseudomonas syringae pv tomato. Resistance to P. s. tomato depends upon expression of the Pto locus in tomato, which encodes a protein with similarity to serine/threonine protein kinases and recognizes pathogen strains expressing the avirulence gene avrPto. Eleven tomato mutants were isolated with altered resistance to P. s. tomato strains expressing avrPto. We identified mutations both in the Pto resistance locus and in a new locus designated Prf (for Pseudomonas resistance and fenthion sensitivity). The genetic approach allowed us to dissect the roles of these loci in signal transduction in response to pathogen attack. Lines carrying mutations in the Pto locus vary 200-fold in the degree to which they are susceptible to P. s. tomato strains expressing avrPto. The pto mutants retain sensitivity to the organophosphate insecticide fenthion; this trait segregates with Pto in genetic crosses. This result suggested that contrary to previous hypotheses, the Pto locus controls pathogen recognition but not fenthion sensitivity. Interestingly, mutations in the prf locus result in both complete susceptibility to P. s. tomato and insensitivity to fenthion, suggesting that Prf plays a role in tomato signaling in response to both pathogen elicitors and fenthion. Because pto and prf mutations do not alter recognition of Xanthomonas campestris strains expressing avrBsP, an avirulence gene recognized by all tested tomato cultivars, Prf does not play a general role in disease resistance but possibly functions specifically in resistance against P. s. tomato. Genetic analysis of F2 populations from crosses of pto and prf homozygotes indicated that the Pto and Prf loci are tightly linked. PMID:7911348

  11. A novel quantitative trait locus for Fusarium head blight resistance in chromosome 7A of wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A Chinese Spring-Sumai 3 chromosome 7A disomic substitution line (CS-Sumai 3-7ADSL) was reported to have a high level of Fusarium head blight (FHB) resistance for symptom spread within a spike (Type II) and low deoxynivalenol accumulation in infected kernels (Type III), but quantitative trait locus ...

  12. Combined nickel-cobalt-cadmium resistance encoded by the ncc locus of Alcaligenes xylosoxidans 31A.

    PubMed Central

    Schmidt, T; Schlegel, H G

    1994-01-01

    The nickel-cobalt-cadmium resistance genes carried by plasmid pTOM9 of Alcaligenes xylosoxidans 31A are located on a 14.5-kb BamHI fragment. By random Tn5 insertion mutagenesis, the fragment was shown to contain two distinct nickel resistance loci, ncc and nre. The ncc locus causes a high-level combined nickel, cobalt, and cadmium resistance in strain AE104, which is a cured derivative of the metal-resistant bacterium Alcaligenes eutrophus CH34. ncc is not expressed in Escherichia coli. The nre locus causes low-level nickel resistance in both Alcaligenes and E. coli strains. The nucleotide sequence of the ncc locus revealed seven open reading frames designated nccYXHCBAN. The corresponding predicted proteins share strong similarities with proteins encoded by the metal resistance loci cnr (cnrYXHCBA) and czc (czcRCBAD) of A. eutrophus CH34. When different DNA fragments carrying ncc genes were heterologously expressed under the control of the bacteriophage T7 promoter, five protein bands representing NccA (116 kDa), NccB (40 kDa), NccC (46 kDa), NccN (23.5 kDa), and NccX (16.5 kDa) were detected. Images PMID:7961470

  13. Parallel Loss-of-Function at the RPM1 Bacterial Resistance Locus in Arabidopsis thaliana

    PubMed Central

    Rose, Laura; Atwell, Susanna; Grant, Murray; Holub, Eric B.

    2012-01-01

    Dimorphism at the Resistance to Pseudomonas syringae pv. maculicola 1 (RPM1) locus is well documented in natural populations of Arabidopsis thaliana and has been portrayed as a long-term balanced polymorphism. The haplotype from resistant plants contains the RPM1 gene, which enables these plants to recognize at least two structurally unrelated bacterial effector proteins (AvrB and AvrRpm1) from bacterial crop pathogens. A complete deletion of the RPM1 coding sequence has been interpreted as a single event resulting in susceptibility in these individuals. Consequently, the ability to revert to resistance or for alternative R-gene specificities to evolve at this locus has also been lost in these individuals. Our survey of variation at the RPM1 locus in a large species-wide sample of A. thaliana has revealed four new loss-of-function alleles that contain most of the intervening sequence of the RPM1 open reading frame. Multiple loss-of-function alleles may have originated due to the reported intrinsic cost to plants expressing the RPM1 protein. The frequency and geographic distribution of rpm1 alleles observed in our survey indicate the parallel origin and maintenance of these loss-of-function mutations and reveal a more complex history of natural selection at this locus than previously thought. PMID:23272006

  14. Evolution and selection of Rhg1, a copy-number variant nematode-resistance locus

    PubMed Central

    Lee, Tong Geon; Kumar, Indrajit; Diers, Brian W; Hudson, Matthew E

    2015-01-01

    The soybean cyst nematode (SCN) resistance locus Rhg1 is a tandem repeat of a 31.2 kb unit of the soybean genome. Each 31.2-kb unit contains four genes. One allele of Rhg1, Rhg1-b, is responsible for protecting most US soybean production from SCN. Whole-genome sequencing was performed, and PCR assays were developed to investigate allelic variation in sequence and copy number of the Rhg1 locus across a population of soybean germplasm accessions. Four distinct sequences of the 31.2-kb repeat unit were identified, and some Rhg1 alleles carry up to three different types of repeat unit. The total number of copies of the repeat varies from 1 to 10 per haploid genome. Both copy number and sequence of the repeat correlate with the resistance phenotype, and the Rhg1 locus shows strong signatures of selection. Significant linkage disequilibrium in the genome outside the boundaries of the repeat allowed the Rhg1 genotype to be inferred using high-density single nucleotide polymorphism genotyping of 15 996 accessions. Over 860 germplasm accessions were found likely to possess Rhg1 alleles. The regions surrounding the repeat show indications of non-neutral evolution and high genetic variability in populations from different geographic locations, but without evidence of fixation of the resistant genotype. A compelling explanation of these results is that balancing selection is in operation at Rhg1. PMID:25735447

  15. New parameterization of the PM3 method for monosaccharides

    NASA Astrophysics Data System (ADS)

    Mane, Jonathan Y.; Klobukowski, Mariusz

    2010-11-01

    We derived new parameters for the semi-empirical PM3 method, PM3MS, designed for studies of saccharides. The parameters were optimized using genetic algorithm procedure. We used the MP2/cc-pVTZ energies and optimized geometries of monosaccharides as the reference set. Results show that compared to the standard PM3, the new PM3MS parameters predict better ordering of the conformers energy both for the members of the training set, as well as those outside the training set.

  16. Genetic mapping of microsatellite markers around the arcelin bruchid resistance locus in common bean.

    PubMed

    Blair, Matthew W; Muñoz, Claritza; Buendía, Héctor F; Flower, José; Bueno, Juan M; Cardona, César

    2010-07-01

    The deployment in common beans (Phaseolus vulgaris L.) of arcelin-based bruchid resistance could help reduce post-harvest storage losses to the Mexican bean weevil [(Zabrotes subfasciatus (Boheman)]. Arcelin is a member of the arcelin-phytohemagglutinin-alpha-amylase inhibitor (APA) family of seed proteins, which has been extensively studied but not widely used in bean breeding programs. The purpose of this study was to evaluate microsatellite markers for genetic analysis of arcelin-based bruchid resistance and to determine the orientation of markers and the rate of recombination around the APA locus. A total of 10 previously developed microsatellites and 22 newly developed markers based on a sequenced BAC from the APA locus were screened for polymorphism and of these 15 were mapped with an F(2) population of 157 individuals resulting from a susceptible x resistant cross of SEQ1006 x RAZ106 that segregated for both the arcelin 1 allele and resistance to the bruchid, Z. subfasciatus. Microsatellites derived from APA gene sequences were linked within 0.8 cM of each other and were placed relative to the rest of the b04 linkage group. In a comparison of genetic to physical distance on the BAC sequence, recombination was found to be moderate with a ratio of 125 kb/cM, but repressed within the APA locus itself. Several markers were predicted to be very effective for genetic studies or marker-assisted selection, based on their significant associations with bruchid resistance and on low adult insect emergence and positions flanking the arcelin and phytohemagglutinin genes. PMID:20358173

  17. Genetic and molecular characterization of the maize rp3 rust resistance locus.

    PubMed Central

    Webb, Craig A; Richter, Todd E; Collins, Nicholas C; Nicolas, Marie; Trick, Harold N; Pryor, Tony; Hulbert, Scot H

    2002-01-01

    In maize, the Rp3 gene confers resistance to common rust caused by Puccinia sorghi. Flanking marker analysis of rust-susceptible rp3 variants suggested that most of them arose via unequal crossing over, indicating that rp3 is a complex locus like rp1. The PIC13 probe identifies a nucleotide binding site-leucine-rich repeat (NBS-LRR) gene family that maps to the complex. Rp3 variants show losses of PIC13 family members relative to the resistant parents when probed with PIC13, indicating that the Rp3 gene is a member of this family. Gel blots and sequence analysis suggest that at least 9 family members are at the locus in most Rp3-carrying lines and that at least 5 of these are transcribed in the Rp3-A haplotype. The coding regions of 14 family members, isolated from three different Rp3-carrying haplotypes, had DNA sequence identities from 93 to 99%. Partial sequencing of clones of a BAC contig spanning the rp3 locus in the maize inbred line B73 identified five different PIC13 paralogues in a region of approximately 140 kb. PMID:12242248

  18. Genetic and molecular characterization of the maize rp3 rust resistance locus.

    PubMed

    Webb, Craig A; Richter, Todd E; Collins, Nicholas C; Nicolas, Marie; Trick, Harold N; Pryor, Tony; Hulbert, Scot H

    2002-09-01

    In maize, the Rp3 gene confers resistance to common rust caused by Puccinia sorghi. Flanking marker analysis of rust-susceptible rp3 variants suggested that most of them arose via unequal crossing over, indicating that rp3 is a complex locus like rp1. The PIC13 probe identifies a nucleotide binding site-leucine-rich repeat (NBS-LRR) gene family that maps to the complex. Rp3 variants show losses of PIC13 family members relative to the resistant parents when probed with PIC13, indicating that the Rp3 gene is a member of this family. Gel blots and sequence analysis suggest that at least 9 family members are at the locus in most Rp3-carrying lines and that at least 5 of these are transcribed in the Rp3-A haplotype. The coding regions of 14 family members, isolated from three different Rp3-carrying haplotypes, had DNA sequence identities from 93 to 99%. Partial sequencing of clones of a BAC contig spanning the rp3 locus in the maize inbred line B73 identified five different PIC13 paralogues in a region of approximately 140 kb. PMID:12242248

  19. Rpv10: a new locus from the Asian Vitis gene pool for pyramiding downy mildew resistance loci in grapevine.

    PubMed

    Schwander, Florian; Eibach, Rudolf; Fechter, Iris; Hausmann, Ludger; Zyprian, Eva; Töpfer, Reinhard

    2012-01-01

    A population derived from a cross between grapevine breeding strain Gf.Ga-52-42 and cultivar 'Solaris' consisting of 265 F1-individuals was genetically mapped using SSR markers and screened for downy mildew resistance. Quantitative trait locus (QTL) analysis revealed two strong QTLs on linkage groups (LGs) 18 and 09. The locus on LG 18 was found to be identical with the previously described locus Rpv3 and is transmitted by Gf.Ga-52-42. 'Solaris' transmitted the resistance-related locus on LG 09 explaining up to 50% of the phenotypic variation in the population. This downy mildew resistance locus is named Rpv10 for resistance to Plasmopara viticola. Rpv10 was initially introgressed from Vitis amurensis, a wild species of the Asian Vitis gene pool. The one-LOD supported confidence interval of the QTL spans a section of 2.1 centi Morgan (cM) corresponding to 314 kb in the reference genome PN40024 (12x). Eight resistance gene analogues (RGAs) of the NBS-LRR type and additional resistance-linked genes are located in this region of PN40024. The F1 sub-population which contains the Rpv3 as well as the Rpv10 locus showed a significantly higher degree of resistance, indicating additive effects by pyramiding of resistance loci. Possibilities for using the resistance locus Rpv10 in a grapevine breeding programme are discussed. Furthermore, the marker data revealed 'Severnyi' × 'Muscat Ottonel' as the true parentage for the male parent of 'Solaris'. PMID:21935694

  20. A mutagenesis-derived broad-spectrum disease resistance locus in wheat.

    PubMed

    Campbell, Jackie; Zhang, Hongtao; Giroux, Michael J; Feiz, Leila; Jin, Yue; Wang, Meinan; Chen, Xianming; Huang, Li

    2012-07-01

    Wheat leaf rust, stem rust, stripe rust, and powdery mildew caused by the fungal pathogens Puccinia triticina, P. graminis f. sp. tritici, P. striiformis f. sp. tritici, and Blumeria graminis f. sp. tritici, respectively, are destructive diseases of wheat worldwide. Breeding durable disease resistance cultivars rely largely on continually introgressing new resistance genes, especially the genes with different defense mechanisms, into adapted varieties. Here, we describe a new resistance gene obtained by mutagenesis. The mutant, MNR220 (mutagenesis-derived new resistance), enhances resistance to three rusts and powdery mildew, with the characteristics of delayed disease development at the seedling stage and completed resistance at the adult plant stage. Genetic analysis demonstrated that the resistance in MNR220 is conferred by a single semidominant gene mapped on the short arm of chromosome 2B. Gene expression profiling of several pathogenesis-related genes indicated that MNR220 has an elevated and rapid pathogen-induced response. In addition to its potential use in breeding for resistance to multiple diseases, high-resolution mapping and cloning of the disease resistance locus in MNR220 may lead to a better understanding of the regulation of defense responses in wheat. PMID:22446929

  1. Multiple antibiotic resistance (mar) locus in Salmonella enterica serovar typhimurium DT104.

    PubMed

    Randall, L P; Woodward, M J

    2001-03-01

    In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicylate induced marA, whereas a number of antibiotics, disinfectants, and various growth conditions did not. Increased antibiotic resistance was observed upon salicylate induction, although this was shown to be by both mar-dependent and mar-independent pathways. Cyclohexane resistance, however, was induced by salicylate by a mar-dependent pathway. Complementation studies with a plasmid that constitutively expressed marA confirmed the involvement of mar in Salmonella with low-level antibiotic resistance and cyclohexane resistance, although the involvement of mar in down regulation of OmpF was unclear. However, marA overexpression did increase the expression of a ca. 50-kDa protein, but its identity remains to be elucidated. Passage of the marA::gfp reporter mutant with increasing levels of tetracycline, a method reported to select for mar mutants in Escherichia coli, led to both multiple-antibiotic and cyclohexane resistance. Collectively, these data indicate that low-level antibiotic resistance, cyclohexane resistance, and modulation of OMPs in Salmonella, as in E. coli, can occur in both a mar-dependent and mar-independent manner. PMID:11229910

  2. Allelic and haplotypic diversity at the rp1 rust resistance locus of maize.

    PubMed Central

    Smith, Shavannor M; Pryor, Anthony J; Hulbert, Scot H

    2004-01-01

    The maize Rp1 rust resistance locus is a complex consisting of a family of closely related resistance genes. The number of Rp1 paralogs in different maize lines (haplotypes) varied from a single gene in some stocks of the inbred A188 to >50 genes in haplotypes carrying the Rp1-A and Rp1-H specificities. The sequences of paralogs in unrelated haplotypes differ, indicating that the genetic diversity of Rp1-related genes is extremely broad in maize. Two unrelated haplotypes with five or nine paralogs had identical resistance phenotypes (Rp1-D) encoded in genes that differed by three nucleotides resulting in a single amino acid substitution. Genes in some haplotypes are more similar to each other than to any of the genes in other haplotypes indicating that they are evolving in a concerted fashion. PMID:15342531

  3. Locus-specific genetic differentiation at Rw among warfarin-resistant rat (Rattus norvegicus) populations.

    PubMed Central

    Kohn, Michael H; Pelz, Hans-Joachim; Wayne, Robert K

    2003-01-01

    Populations may diverge at fitness-related genes as a result of adaptation to local conditions. The ability to detect this divergence by marker-based genomic scans depends on the relative magnitudes of selection, recombination, and migration. We survey rat (Rattus norvegicus) populations to assess the effect that local selection with anticoagulant rodenticides has had on microsatellite marker variation and differentiation at the warfarin resistance gene (Rw) relative to the effect on the genomic background. Initially, using a small sample of 16 rats, we demonstrate tight linkage of microsatellite D1Rat219 to Rw by association mapping of genotypes expressing an anticoagulant-rodenticide-insensitive vitamin K 2,3-epoxide reductase (VKOR). Then, using allele frequencies at D1Rat219, we show that predicted and observed resistance levels in 27 populations correspond, suggesting intense and recent selection for resistance. A contrast of F(ST) values between D1Rat219 and the genomic background revealed that rodenticide selection has overwhelmed drift-mediated population structure only at Rw. A case-controlled design distinguished these locus-specific effects of selection at Rw from background levels of differentiation more effectively than a population-controlled approach. Our results support the notion that an analysis of locus-specific population genetic structure may assist the discovery and mapping of novel candidate loci that are the object of selection or may provide supporting evidence for previously identified loci. PMID:12871915

  4. Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development and utilization of genetic markers play a pivotal role in marker assisted breeding of wheat cultivars with pyramids of disease resistance genes. The objective of this study is to develop a closed tube, gel-free assay for high throughput genotyping of leaf rust resistance locus Lr21. Poly...

  5. Mining Disease-Resistance Genes in Roses: Functional and Molecular Characterization of the Rdr1 Locus

    PubMed Central

    Terefe-Ayana, Diro; Yasmin, Aneela; Le, Thanh Loan; Kaufmann, Helgard; Biber, Anja; Kühr, Astrid; Linde, Marcus; Debener, Thomas

    2011-01-01

    The interaction of roses with the leaf spot pathogen Diplocarpon rosae (the cause of black spot on roses) is an interesting pathosystem because it involves a long-lived woody perennial, with life history traits very different from most model plants, and a hemibiotrophic pathogen with moderate levels of gene flow. Here we present data on the molecular structure of the first monogenic dominant resistance gene from roses, Rdr1, directed against one isolate of D. rosae. Complete sequencing of the locus carrying the Rdr1 gene resulted in a sequence of 265,477 bp with a cluster of nine highly related TIR–NBS–LRR (TNL) candidate genes. After sequencing revealed candidate genes for Rdr1, we implemented a gene expression analysis and selected five genes out of the nine TNLs. We then silenced the whole TNL gene family using RNAi (Rdr1–RNAi) constructed from the most conserved sequence region and demonstrated a loss of resistance in the normally resistant genotype. To identify the functional TNL gene, we further screened the five TNL candidate genes with a transient leaf infiltration assay. The transient expression assay indicated a single TNL gene (muRdr1H), partially restoring resistance in the susceptible genotype. Rdr1 was found to localize within the muRdr1 gene family; the genes within this locus contain characteristic motifs of active TNL genes and belong to a young cluster of R genes. The transient leaf assay can be used to further analyze the rose black spot interaction and its evolution, extending the analyses to additional R genes and to additional pathogenic types of the pathogen. PMID:22639591

  6. Genetic Polymorphism of agr Locus and Antibiotic Resistance of Staphylococcus aureus at two hospitals in Pakistan

    PubMed Central

    Khan, Sadia; Rasheed, Faisal; Zahra, Rabaab

    2014-01-01

    Objective: The accessory gene regulator (agr) locus in Staphylococcus aureus (S. aureus) is a global regulator of quorum sensing and controls the production of virulence factors. This study was carried out to investigate the agr specific groups both in methicillin resistant and sensitive Staphylococcus aureus (MRSA and MSSA) and their relation with antibiotic resistance. Methods: A total of 90 clinical S. aureus isolates were studied from two tertiary care hospitals. The isolates were identified by standard biochemical tests. Methicillin resistance was confirmed by oxacillin and cefoxitin resistance. Multiplex PCR was used to determine the agr groups. Results: MRSA prevalence was found to be 53.3%.The agr groups’ distribution in MRSA was as follows: 22 (45.8%) belonged to group I, 14 (29.1%) belonged to group III and 2 (4.1%) belonged to group II. agrIV was not detected in MRSA. For 17 isolates, the agr group was not detected.agr III isolates showed higher antibiotic resistance than agrI isolates except in case of oxacillin and linezolid. Conclusions: Strict infection control policy and antibiotic guidelines should be adopted to control the problem of MRSA. Higher prevalence of agr I and agr III shows that they are dominant agr groups of our area. PMID:24639855

  7. Artemisinin Resistance-Associated Polymorphisms at the K13-Propeller Locus Are Absent in Plasmodium falciparum Isolates from Haiti

    PubMed Central

    Carter, Tamar E.; Boulter, Alexis; Existe, Alexandre; Romain, Jean R.; St. Victor, Jean Yves; Mulligan, Connie J.; Okech, Bernard A.

    2015-01-01

    Antimalarial drugs are a key tool in malaria elimination programs. With the emergence of artemisinin resistance in southeast Asia, an effort to identify molecular markers for surveillance of resistant malaria parasites is underway. Non-synonymous mutations in the kelch propeller domain (K13-propeller) in Plasmodium falciparum have been associated with artemisinin resistance in samples from southeast Asia, but additional studies are needed to characterize this locus in other P. falciparum populations with different levels of artemisinin use. Here, we sequenced the K13-propeller locus in 82 samples from Haiti, where limited government oversight of non-governmental organizations may have resulted in low-level use of artemisinin-based combination therapies. We detected a single-nucleotide polymorphism (SNP) at nucleotide 1,359 in a single isolate. Our results contribute to our understanding of the global genomic diversity of the K13-propeller locus in P. falciparum populations. PMID:25646258

  8. Artemisinin resistance-associated polymorphisms at the K13-propeller locus are absent in Plasmodium falciparum isolates from Haiti.

    PubMed

    Carter, Tamar E; Boulter, Alexis; Existe, Alexandre; Romain, Jean R; St Victor, Jean Yves; Mulligan, Connie J; Okech, Bernard A

    2015-03-01

    Antimalarial drugs are a key tool in malaria elimination programs. With the emergence of artemisinin resistance in southeast Asia, an effort to identify molecular markers for surveillance of resistant malaria parasites is underway. Non-synonymous mutations in the kelch propeller domain (K13-propeller) in Plasmodium falciparum have been associated with artemisinin resistance in samples from southeast Asia, but additional studies are needed to characterize this locus in other P. falciparum populations with different levels of artemisinin use. Here, we sequenced the K13-propeller locus in 82 samples from Haiti, where limited government oversight of non-governmental organizations may have resulted in low-level use of artemisinin-based combination therapies. We detected a single-nucleotide polymorphism (SNP) at nucleotide 1,359 in a single isolate. Our results contribute to our understanding of the global genomic diversity of the K13-propeller locus in P. falciparum populations. PMID:25646258

  9. Recombination suppression at the dominant Rhg1/Rfs2 locus underlying soybean resistance to the cyst nematode.

    PubMed

    Afzal, Ahmed J; Srour, Ali; Saini, Navinder; Hemmati, Naghmeh; El Shemy, Hany A; Lightfoot, David A

    2012-04-01

    Host resistance to "yellow dwarf" or "moonlight" disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24-48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred. PMID:22200919

  10. Resistance to Puccinia graminis f. sp. avenae in Barley Is Associated with the Rpg5 Locus.

    PubMed

    Dracatos, Peter; Singh, Davinder; Fetch, Tom; Park, Robert

    2015-04-01

    In barley, gene Rpg5 was first identified for providing resistance to the rye stem rust pathogen (Puccinia graminis f. sp. secalis). A subsequent study determined that Rpg5 is required for rpg4-mediated resistance to the wheat stem rust pathogen (P. graminis f. sp. tritici) including pathotype TTKSK ("Ug99"), which poses a major threat to global wheat and barley production. Based on the effectiveness of Rpg5 against P. graminis f. sp. tritici and P. graminis f. sp. secalis, we assessed whether it also conferred resistance to the oat stem rust pathogen (P. graminis f. sp. avenae). A barley F8 recombinant inbred line (RIL) population was produced by crossing 'Q21861' (Rpg1 and Rpg5) with '73-G1' (Rpg1), which is susceptible to P. graminis f. sp. avenae, P. graminis f. sp. secalis, and some pathotypes of P. graminis f. sp. tritici. Seedling tests were performed on the F8 RIL population using Australian pathotypes of P. graminis f. sp. tritici, P. graminis f. sp. secalis, P. graminis f. sp. avenae, and a putative somatic hybrid between P. graminis f. sp. tritici and P. graminis f. sp. secalis known as the 'Scabrum' rust. Segregation in the responses to all rust isolates for the RILs was identical (50 resistant: 52 susceptible), and fitted a 1:1 ratio (X2=0.039, P=0.843), indicating that resistance to all isolates was monogenetically inherited. Screening of the RILs and the parental lines with perfect markers for the functional Rpg1 and Rpg5 resistance alleles indicated that Rpg1 was fixed, while Rpg5 was positive in all resistant lines and negative in all susceptible lines. This suggests that different formae speciales of P. graminis may share common effectors, and that the Rpg5 locus confers resistance to both P. graminis f. sp. tritici and P. graminis f. sp. secalis and the heterologous formae speciales of P. graminis, P. graminis f. sp. avenae. PMID:25870923

  11. Unraveling Genomic Complexity at a Quantitative Disease Resistance Locus in Maize

    PubMed Central

    Jamann, Tiffany M.; Poland, Jesse A.; Kolkman, Judith M.; Smith, Laurie G.; Nelson, Rebecca J.

    2014-01-01

    Multiple disease resistance has important implications for plant fitness, given the selection pressure that many pathogens exert directly on natural plant populations and indirectly via crop improvement programs. Evidence of a locus conditioning resistance to multiple pathogens was found in bin 1.06 of the maize genome with the allele from inbred line “Tx303” conditioning quantitative resistance to northern leaf blight (NLB) and qualitative resistance to Stewart’s wilt. To dissect the genetic basis of resistance in this region and to refine candidate gene hypotheses, we mapped resistance to the two diseases. Both resistance phenotypes were localized to overlapping regions, with the Stewart’s wilt interval refined to a 95.9-kb segment containing three genes and the NLB interval to a 3.60-Mb segment containing 117 genes. Regions of the introgression showed little to no recombination, suggesting structural differences between the inbred lines Tx303 and “B73,” the parents of the fine-mapping population. We examined copy number variation across the region using next-generation sequencing data, and found large variation in read depth in Tx303 across the region relative to the reference genome of B73. In the fine-mapping region, association mapping for NLB implicated candidate genes, including a putative zinc finger and pan1. We tested mutant alleles and found that pan1 is a susceptibility gene for NLB and Stewart’s wilt. Our data strongly suggest that structural variation plays an important role in resistance conditioned by this region, and pan1, a gene conditioning susceptibility for NLB, may underlie the QTL. PMID:25009146

  12. Transcriptome and allele specificity associated with a 3BL locus for Fusarium crown rot resistance in bread wheat.

    PubMed

    Ma, Jian; Stiller, Jiri; Zhao, Qiang; Feng, Qi; Cavanagh, Colin; Wang, Penghao; Gardiner, Donald; Choulet, Frédéric; Feuillet, Catherine; Zheng, You-Liang; Wei, Yuming; Yan, Guijun; Han, Bin; Manners, John M; Liu, Chunji

    2014-01-01

    Fusarium pathogens cause two major diseases in cereals, Fusarium crown rot (FCR) and head blight (FHB). A large-effect locus conferring resistance to FCR disease was previously located to chromosome arm 3BL (designated as Qcrs-3B) and several independent sets of near isogenic lines (NILs) have been developed for this locus. In this study, five sets of the NILs were used to examine transcriptional changes associated with the Qcrs-3B locus and to identify genes linked to the resistance locus as a step towards the isolation of the causative gene(s). Of the differentially expressed genes (DEGs) detected between the NILs, 12.7% was located on the single chromosome 3B. Of the expressed genes containing SNP (SNP-EGs) detected, 23.5% was mapped to this chromosome. Several of the DEGs and SNP-EGs are known to be involved in host-pathogen interactions, and a large number of the DEGs were among those detected for FHB in previous studies. Of the DEGs detected, 22 were mapped in the Qcrs-3B interval and they included eight which were detected in the resistant isolines only. The enrichment of DEG, and not necessarily those containing SNPs between the resistant and susceptible isolines, around the Qcrs-3B locus is suggestive of local regulation of this region by the resistance allele. Functions for 13 of these DEGs are known. Of the SNP-EGs, 28 were mapped in the Qcrs-3B interval and biological functions for 16 of them are known. These results provide insights into responses regulated by the 3BL locus and identify a tractable number of target genes for fine mapping and functional testing to identify the causative gene(s) at this QTL. PMID:25405461

  13. Transcriptome and Allele Specificity Associated with a 3BL Locus for Fusarium Crown Rot Resistance in Bread Wheat

    PubMed Central

    Ma, Jian; Stiller, Jiri; Zhao, Qiang; Feng, Qi; Cavanagh, Colin; Wang, Penghao; Gardiner, Donald; Choulet, Frédéric; Feuillet, Catherine; Zheng, You-Liang; Wei, Yuming; Yan, Guijun; Han, Bin; Manners, John M.; Liu, Chunji

    2014-01-01

    Fusarium pathogens cause two major diseases in cereals, Fusarium crown rot (FCR) and head blight (FHB). A large-effect locus conferring resistance to FCR disease was previously located to chromosome arm 3BL (designated as Qcrs-3B) and several independent sets of near isogenic lines (NILs) have been developed for this locus. In this study, five sets of the NILs were used to examine transcriptional changes associated with the Qcrs-3B locus and to identify genes linked to the resistance locus as a step towards the isolation of the causative gene(s). Of the differentially expressed genes (DEGs) detected between the NILs, 12.7% was located on the single chromosome 3B. Of the expressed genes containing SNP (SNP-EGs) detected, 23.5% was mapped to this chromosome. Several of the DEGs and SNP-EGs are known to be involved in host-pathogen interactions, and a large number of the DEGs were among those detected for FHB in previous studies. Of the DEGs detected, 22 were mapped in the Qcrs-3B interval and they included eight which were detected in the resistant isolines only. The enrichment of DEG, and not necessarily those containing SNPs between the resistant and susceptible isolines, around the Qcrs-3B locus is suggestive of local regulation of this region by the resistance allele. Functions for 13 of these DEGs are known. Of the SNP-EGs, 28 were mapped in the Qcrs-3B interval and biological functions for 16 of them are known. These results provide insights into responses regulated by the 3BL locus and identify a tractable number of target genes for fine mapping and functional testing to identify the causative gene(s) at this QTL. PMID:25405461

  14. Identification of a New Locus, Ptr(t), Required for Rice Blast Resistance Gene Pi-ta-Mediated Resistance

    SciTech Connect

    Jia, Yulin; Martin, Rodger Carl

    2008-01-01

    Resistance to the blast pathogen Magnaporthe oryzae is proposed to be initiated by physical binding of a putative cytoplasmic receptor encoded by a NBS type resistance gene Pi-ta to the processed elicitor encoded by the corresponding avirulence gene AVR-Pita. Here we report the identification of a new locus Ptr(t) that is required for Pi-ta-mediated signal recognition. A Pi-ta expressing susceptible mutant was identified using a genetic screen. Putative mutations at Ptr(t) does not alter recognition specificity to another resistance gene Pi-ks in the Pi-ta homozygote indicate that Ptr(t) is more likely specific to Pi-ta-mediated signal recognition. Genetic crosses of Pi-ta Ptr(t) and Pi-ta ptr(t) homozygotes suggest that Ptr(t) segregate at single dominant nuclear gene. A ratio of 1 resistant: 1 susceptible of a BC1 using Pi-ta Ptr(t) with pi-ta ptr(t) homozygotes indicates that Pi-ta and Ptr(t) are linked and co-segregated. Genotyping of mutants of pi-ta ptr(t) and Pi-ta Ptr(t) homozygotes using ten simple sequence repeat markers spanning 9 megabase of Pi-ta determines that Pi-ta and Ptr(t) are of indica origin. Identification of Ptr(t) is a significant advancement in studying Pi-ta-mediated signal recognition and transduction.

  15. A novel locus of resistance to severe malaria in a region of ancient balancing selection.

    PubMed

    Band, Gavin; Rockett, Kirk A; Spencer, Chris C A; Kwiatkowski, Dominic P

    2015-10-01

    The high prevalence of sickle haemoglobin in Africa shows that malaria has been a major force for human evolutionary selection, but surprisingly few other polymorphisms have been proven to confer resistance to malaria in large epidemiological studies. To address this problem, we conducted a multi-centre genome-wide association study (GWAS) of life-threatening Plasmodium falciparum infection (severe malaria) in over 11,000 African children, with replication data in a further 14,000 individuals. Here we report a novel malaria resistance locus close to a cluster of genes encoding glycophorins that are receptors for erythrocyte invasion by P. falciparum. We identify a haplotype at this locus that provides 33% protection against severe malaria (odds ratio = 0.67, 95% confidence interval = 0.60-0.76, P value = 9.5 × 10(-11)) and is linked to polymorphisms that have previously been shown to have features of ancient balancing selection, on the basis of haplotype sharing between humans and chimpanzees. Taken together with previous observations on the malaria-protective role of blood group O, these data reveal that two of the strongest GWAS signals for severe malaria lie in or close to genes encoding the glycosylated surface coat of the erythrocyte cell membrane, both within regions of the genome where it appears that evolution has maintained diversity for millions of years. These findings provide new insights into the host-parasite interactions that are critical in determining the outcome of malaria infection. PMID:26416757

  16. Recombination between paralogues at the Rp1 rust resistance locus in maize.

    PubMed Central

    Sun, Q; Collins, N C; Ayliffe, M; Smith, S M; Drake, J; Pryor, T; Hulbert, S H

    2001-01-01

    Rp1 is a complex rust resistance locus of maize. The HRp1-D haplotype is composed of Rp1-D and eight paralogues, seven of which also code for predicted nucleotide binding site-leucine rich repeat (NBS-LRR) proteins similar to the Rp1-D gene. The paralogues are polymorphic (DNA identities 91-97%), especially in the C-terminal LRR domain. The remaining family member encodes a truncated protein that has no LRR domain. Seven of the nine family members, including the truncated gene, are transcribed. Sequence comparisons between paralogues provide evidence for past recombination events between paralogues and diversifying selection, particularly in the C-terminal half of the LRR domain. Variants selected for complete or partial loss of Rp1-D resistance can be explained by unequal crossing over that occurred mostly within coding regions. The Rp1-D gene is altered or lost in all variants, the recombination breakpoints occur throughout the genes, and most recombinant events (9/14 examined) involved the same untranscribed paralogue with the Rp1-D gene. One recombinant with a complete LRR from Rp1-D, but the amino-terminal portion from another homologue, conferred the Rp1-D specificity but with a reduced level of resistance. PMID:11333250

  17. Distinct copy number, coding sequence and locus methylation patterns underlie Rhg1-mediated soybean resistance to soybean cyst nematode

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copy number variation of kilobase-scale genomic DNA segments, beyond presence/absence polymorphisms, can be an important driver of adaptive traits. Rhg1 is a widely utilized quantitative trait locus that makes the strongest known contribution to resistance against soybean cyst nematode (SCN; Hetero...

  18. On the Locus Formed by the Maximum Heights of Projectile Motion with Air Resistance

    ERIC Educational Resources Information Center

    Hernandez-Saldana, H.

    2010-01-01

    We present an analysis on the locus formed by the set of maxima of the trajectories of a projectile launched in a medium with linear drag. Such a place, the locus of apexes, is written in terms of the Lambert "W" function in polar coordinates, confirming the special role played by this function in the problem. To characterize the locus, a study of…

  19. Three-dimensional modeling and diversity analysis reveals distinct AVR recognition sites and evolutionary pathways in wild and domesticated wheat Pm3 R genes.

    PubMed

    Sela, Hanan; Spiridon, Laurentiu N; Ashkenazi, Haim; Bhullar, Navreet K; Brunner, Susanne; Petrescu, Andrei-Jose; Fahima, Tzion; Keller, Beat; Jordan, Tina

    2014-08-01

    The Pm3 gene confers resistance against wheat powdery mildew. Studies of Pm3 diversity have shown that Pm3 alleles isolated from southern populations of wild emmer wheat located in Lebanon, Jordan, Israel, and Syria are more diverse and more distant from bread wheat alleles than alleles from the northern wild wheat populations located in Turkey, Iran, and Iraq. Therefore, southern populations from Israel were studied extensively to reveal novel Pm3 alleles that are absent from the cultivated gene pool. Candidate Pm3 genes were isolated via a polymerase chain reaction cloning approach. Known and newly identified Pm3 genes were subjected to variation analysis and polymorphic amino acid residues were superimposed on a three-dimensional (3D) model of PM3. The region of highest interspecies diversity between Triticum aestivum and T. dicoccoides lies in leucine-rich repeats (LRR) 19 to 24, whereas most intraspecies diversity in T. aestivum is located in LRR 25 to 28. Interestingly, these two regions are separated by one large LRR whose propensity for flexibility facilitates the conformation of the PM3 LRR domain into two differently structured models. The combination of evolutionary and protein 3D structure analysis revealed that Pm3 genes in wild and domesticated wheat show different evolutionary histories which might have been triggered through different interactions with the powdery mildew pathogen. PMID:24742072

  20. Cloning and characterization of XiR1, a locus responsible for dagger nematode resistance in grape

    PubMed Central

    Hwang, Chin-Feng; Xu, Kenong; Hu, Rong; Zhou, Rita; Riaz, Summaira

    2010-01-01

    The dagger nematode, Xiphinemaindex, feeds aggressively on grape roots and in the process, vectors grapevine fanleaf virus (GFLV) leading to the severe viral disease known as fanleaf degeneration. Resistance to X. index and GFLV has been the key objective of grape rootstock breeding programs. A previous study found that resistance to X. index derived from Vitis arizonica was largely controlled by a major quantitative trait locus, XiR1 (X. index Resistance 1), located on chromosome 19. The study presented here develops high-resolution genetic and physical maps in an effort to identify the XiR1 gene(s). The mapping was carried out with 1,375 genotypes in three populations derived from D8909-15, a resistant selection from a cross of V. rupestris A. de Serres (susceptible) × V. arizonica b42-26 (resistant). Resistance to X. index was evaluated on 99 informative recombinants that were identified by screening the three populations with two markers flanking the XiR1 locus. The high-resolution genetic map of XiR1 was primarily constructed with seven DNA markers developed in this study. Physical mapping of XiR1 was accomplished by screening three bacterial artificial chromosome (BAC) libraries constructed from D8909-15, V. vinifera Cabernet Sauvignon and V. arizonica b42-26. A total of 32 BAC clones were identified and the XiR1 locus was delineated within a 115 kb region. Sequence analysis of three BAC clones identified putative nucleotide binding/leucine-rich repeat (NB-LRR) genes. This is the first report of a closely linked major gene locus responsible for ectoparasitic nematode resistance. The markers developed from this study are being used to expedite the breeding of resistant grape rootstocks. PMID:20490447

  1. Identification of a new locus, Ptr(t), required for rice blast resistance gene Pi-ta-mediated resistance.

    PubMed

    Jia, Yulin; Martin, Rodger

    2008-04-01

    Resistance to the blast pathogen Magnaporthe oryzae is proposed to be initiated by physical binding of a putative cytoplasmic receptor encoded by a nucleotide binding site-type resistance gene, Pi-ta, to the processed elicitor encoded by the corresponding avirulence gene AVR-Pita. Here, we report the identification of a new locus, Ptr(t), that is required for Pi-ta-mediated signal recognition. A Pi-ta-expressing susceptible mutant was identified using a genetic screen. Putative mutations at Ptr(t) do not alter recognition specificity to another resistance gene, Pi-k(s), in the Pi-ta homozygote, indicating that Ptr(t) is more likely specific to Pi-ta-mediated signal recognition. Genetic crosses of Pi-ta Ptr(t) and Pi-ta ptr(t) homozygotes suggest that Ptr(t) segregates as a single dominant nuclear gene. A ratio of 1:1 (resistant/susceptible) of a population of BC1 of Pi-ta Ptr(t) with pi-ta ptr(t) homozygotes indicates that Pi-ta and Ptr(t) are linked and cosegregate. Genotyping of mutants of pi-ta ptr(t) and Pi-ta Ptr(t) homozygotes using ten simple sequence repeat markers at the Pi-ta region determined that Pi-ta and Ptr(t) are located within a 9-megabase region and are of indica origin. Identification of Ptr(t) is a significant advancement in studying Pi-ta-mediated signal recognition and transduction. PMID:18321185

  2. A Locus at 5q33.3 Confers Resistance to Tuberculosis in Highly Susceptible Individuals.

    PubMed

    Sobota, Rafal S; Stein, Catherine M; Kodaman, Nuri; Scheinfeldt, Laura B; Maro, Isaac; Wieland-Alter, Wendy; Igo, Robert P; Magohe, Albert; Malone, LaShaunda L; Chervenak, Keith; Hall, Noemi B; Modongo, Chawangwa; Zetola, Nicola; Matee, Mecky; Joloba, Moses; Froment, Alain; Nyambo, Thomas B; Moore, Jason H; Scott, William K; Lahey, Timothy; Boom, W Henry; von Reyn, C Fordham; Tishkoff, Sarah A; Sirugo, Giorgio; Williams, Scott M

    2016-03-01

    Immunosuppression resulting from HIV infection increases the risk of progression to active tuberculosis (TB) both in individuals newly exposed to Mycobacterium tuberculosis (MTB) and in those with latent infections. We hypothesized that HIV-positive individuals who do not develop TB, despite living in areas where it is hyperendemic, provide a model of natural resistance. We performed a genome-wide association study of TB resistance by using 581 HIV-positive Ugandans and Tanzanians enrolled in prospective cohort studies of TB; 267 of these individuals developed active TB, and 314 did not. A common variant, rs4921437 at 5q33.3, was significantly associated with TB (odds ratio = 0.37, p = 2.11 × 10(-8)). This variant lies within a genomic region that includes IL12B and is embedded in an H3K27Ac histone mark. The locus also displays consistent patterns of linkage disequilibrium across African populations and has signals of strong selection in populations from equatorial Africa. Along with prior studies demonstrating that therapy with IL-12 (the cytokine encoded in part by IL12B, associated with longer survival following MTB infection in mice deficient in CD4 T cells), our results suggest that this pathway might be an excellent target for the development of new modalities for treating TB, especially for HIV-positive individuals. Our results also indicate that studying extreme disease resistance in the face of extensive exposure can increase the power to detect associations in complex infectious disease. PMID:26942285

  3. Genetic analyses of the major and minor locus groups of bacterial wilt resistance in tobacco using a diallel cross design.

    PubMed

    Qian, Y L; Chen, J; Dong, J J; Wu, Z C; Liu, Y H; Xue, B Y; Shao, F W; Sun, X Y

    2016-01-01

    Tobacco germplasm samples with various levels of resistance to bacterial wilt were selected to construct F1 combinations of parental inbred lines and orthogonal diallel crosses using samples collected in 2009 (15 germplasms), 2010 (15 germplasms), and 2011 (16 germplasms). A total of 1/2P (P + 1) experimental materials were used for analysis. Based on the analyses of major and minor locus groups, genetic effects on the incidence rate and index of bacterial wilt in tobacco were investigated on the 15th and 25th day during the early stage. Significant effects were observed in major locus groups, but not in minor locus groups. Specifically, adjacent major locus groups (J1 = 13,056 and J1 = 13,055; J1 = 14,080 and J1 = 14,079) were detected in both the first and second analyses with considerable effects. Based on the additive effects of minor locus groups on the rate and index of bacterial wilt, the effects on the incidence rates of Yunyan 85, DB101, and RG11 as well as the effects on the disease index of the latter two germplasms reached the maximum. This was consistent with the disease resistance indicators of these tobacco varieties in the field (corresponding broad heritability >20%). Genetic homozygous dominant loci (+ +) increased the rate of bacterial wilt (susceptible), whereas homozygous recessive loci (- -) reduced the index of bacterial wilt (resistant) with considerable additive effects and low dominant effects, suggesting that the inheritance of the bacterial wilt rate and index in tobacco mainly relies on additive inheritance. PMID:26909932

  4. Genome dynamics and evolution of the Mla (powdery mildew) resistance locus in barley.

    PubMed

    Wei, Fusheng; Wing, Rod A; Wise, Roger P

    2002-08-01

    Genes that confer defense against pathogens often are clustered in the genome and evolve via diverse mechanisms. To evaluate the organization and content of a major defense gene complex in cereals, we determined the complete sequence of a 261-kb BAC contig from barley cv Morex that spans the Mla (powdery mildew) resistance locus. Among the 32 predicted genes on this contig, 15 are associated with plant defense responses; 6 of these are associated with defense responses to powdery mildew disease but function in different signaling pathways. The Mla region is organized as three gene-rich islands separated by two nested complexes of transposable elements and a 45-kb gene-poor region. A heterochromatic-like region is positioned directly proximal to Mla and is composed of a gene-poor core with 17 families of diverse tandem repeats that overlap a hypermethylated, but transcriptionally active, gene-dense island. Paleontology analysis of long terminal repeat retrotransposons indicates that the present Mla region evolved over a period of >7 million years through a variety of duplication, inversion, and transposon-insertion events. Sequence-based recombination estimates indicate that R genes positioned adjacent to nested long terminal repeat retrotransposons, such as Mla, do not favor recombination as a means of diversification. We present a model for the evolution of the Mla region that encompasses several emerging features of large cereal genomes. PMID:12172030

  5. [Control locus, stress resistance and personal growth of the participants in experiment Mars-500].

    PubMed

    Solcova, I; Vinokhodova, A G

    2013-01-01

    The article deals with positive personal transformations in a simulated space mission. The investigation was focused on the aspects of control locus, stamina, proactive behavior to overcome challenges, and stress-related personal growth. Besides, ingenious psychophysiological techniques designed to select Russian cosmonauts were used for assessing stress-resistance and ability to control own emotions voluntarily. Experiment Mars-500 simulated the basic features of a mission to Mars. The crew consisted of 6 males 27 to 38 years of age who volunteered to spend 520 days in isolation and confinement in the IBMP experimental facility (Moscow). To detect personality changes, the volunteers were tested before the experiment and after its completion. According to the test results, the participants commonly demonstrated the ability to see the bright side of the Mars-500 adversities, which most often was caused by their social growth. Positive changes were particularly pronounced in the crewmembers who possessed a better ability to control own emotions. The simulated challenges were also beneficial for personal growth of the volunteers. PMID:24032161

  6. Quantitative trait locus mapping and functional genomics of an organophosphate resistance trait in the western corn rootworm, Diabrotica virgifera virgifera.

    PubMed

    Coates, B S; Alves, A P; Wang, H; Zhou, X; Nowatzki, T; Chen, H; Rangasamy, M; Robertson, H M; Whitfield, C W; Walden, K K; Kachman, S D; French, B W; Meinke, L J; Hawthorne, D; Abel, C A; Sappington, T W; Siegfried, B D; Miller, N J

    2016-02-01

    The western corn rootworm, Diabrotica virgifera virgifera, is an insect pest of corn and population suppression with chemical insecticides is an important management tool. Traits conferring organophosphate insecticide resistance have increased in frequency amongst D. v. virgifera populations, resulting in the reduced efficacy in many corn-growing regions of the USA. We used comparative functional genomic and quantitative trait locus (QTL) mapping approaches to investigate the genetic basis of D. v. virgifera resistance to the organophosphate methyl-parathion. RNA from adult methyl-parathion resistant and susceptible adults was hybridized to 8331 microarray probes. The results predicted that 11 transcripts were significantly up-regulated in resistant phenotypes, with the most significant (fold increases ≥ 2.43) being an α-esterase-like transcript. Differential expression was validated only for the α-esterase (ST020027A20C03), with 11- to 13-fold greater expression in methyl-parathion resistant adults (P < 0.05). Progeny with a segregating methyl-parathion resistance trait were obtained from a reciprocal backcross design. QTL analyses of high-throughput single nucleotide polymorphism genotype data predicted involvement of a single genome interval. These data suggest that a specific carboyxesterase may function in field-evolved corn rootworm resistance to organophosphates, even though direct linkage between the QTL and this locus could not be established. PMID:26566705

  7. Intragenic recombination and diversifying selection contribute to the evolution of downy mildew resistance at the RPP8 locus of Arabidopsis.

    PubMed Central

    McDowell, J M; Dhandaydham, M; Long, T A; Aarts, M G; Goff, S; Holub, E B; Dangl, J L

    1998-01-01

    Pathogen resistance (R) genes of the NBS-LRR class (for nucleotide binding site and leucine-rich repeat) are found in many plant species and confer resistance to a diverse spectrum of pathogens. Little is known about the mechanisms that drive NBS-LRR gene evolution in the host-pathogen arms race. We cloned the RPP8 gene (for resistance to Peronospora parasitica) and compared the structure of alleles at this locus in resistant Landsberg erecta (Ler-0) and susceptible Columbia (Col-0) accessions. RPP8-Ler encodes an NBS-LRR protein with a putative N-terminal leucine zipper and is more closely related to previously cloned R genes that confer resistance to bacterial pathogens than it is to other known RPP genes. The RPP8 haplotype in Ler-0 contains the functional RPP8-Ler gene and a nonfunctional homolog, RPH8A. In contrast, the rpp8 locus in Col-0 contains a single chimeric gene, which was likely derived from unequal crossing over between RPP8-Ler and RPH8A ancestors within a Ler-like haplotype. Sequence divergence among RPP8 family members has been accelerated by positive selection on the putative ligand binding region in the LRRs. These observations indicate that NBS-LRR molecular evolution is driven by the same mechanisms that promote rapid sequence diversification among other genes involved in non-self-recognition. PMID:9811794

  8. Are transporter genes other than the chloroquine resistance locus (pfcrt) and multidrug resistance gene (pfmdr) associated with antimalarial drug resistance?

    PubMed

    Anderson, Timothy J C; Nair, Shalini; Qin, Huang; Singlam, Sittaporn; Brockman, Alan; Paiphun, Lucy; Nosten, François

    2005-06-01

    Mu et al. (Mu, J., M. T. Ferdig, X. Feng, D. A. Joy, J. Duan, T. Furuya, G. Subramanian, L. Aravind, R. A. Cooper, J. C. Wootton, M. Xiong, and X. Z. Su, Mol. Microbiol. 49:977-989, 2003) recently reported exciting associations between nine new candidate transporter genes and in vitro resistance to chloroquine (CQ) and quinine (QN), with six of these loci showing association with CQ or QN in a southeast Asian population sample. We replicated and extended this work by examining polymorphisms in these genes and in vitro resistance to eight drugs in parasites collected from the Thailand-Burma border. To minimize problems of multiple testing, we used a two-phase study design, while to minimize problems caused by population structure, we analyzed parasite isolates collected from a single clinic. We first examined associations between genotype and drug response in 108 unique single-clone parasite isolates. We found strong associations between single nucleotide polymorphisms in pfmdr and mefloquine (MFQ), artesunate (AS), and lumefantrine (LUM) response. We also observed associations between an ABC transporter (G7) and response to QN and AS and between another ABC transporter (G49) and response to dihydro-artemisinin (DHA). We reexamined significant associations in an independent sample of 199 unique single-clone infections from the same location. The significant associations with pfmdr-1042 detected in the first survey remained. However, with the exception of the G7-artesunate association, all other associations observed with the nine new candidate transporters disappeared. We also examined linkage disequilibrium (LD) between markers and phenotypic correlations between drug responses. We found minimal LD between genes. Furthermore, we found no correlation between chloroquine and quinine responses, although we did find expected strong correlations between MFQ, QN, AS, DHA, and LUM. To conclude, we found no evidence for an association between 8/9 candidate genes and

  9. Identification of a major Quantitative Trait Locus determining resistance to the organophosphate temephos in the dengue vector mosquito Aedes aegypti.

    PubMed

    Paiva, Marcelo H S; Lovin, Diane D; Mori, Akio; Melo-Santos, Maria A V; Severson, David W; Ayres, Constância F J

    2016-01-01

    Organophosphate insecticides (OP) have extensively been used to control mosquitoes, such as the vector Aedes aegypti. Unfortunately, OP resistance has hampered control programs worldwide. We used Quantitative Trait Locus (QTL) mapping to evaluate temephos resistance in two F1 intercross populations derived from crosses between a resistant Ae. aegypti strain (RecR) and two susceptible strains (MoyoD and Red). A single major effect QTL was identified on chromosome 2 of both segregating populations, named rtt1 (resistance to temephos 1). Bioinformatics analyses identified a cluster of carboxylesterase genes (CCE) within the rtt1 interval. qRT-PCR demonstrated that different CCEs were up-regulated in F2 resistant individuals from both crosses. However, none exceeded the 2-fold expression. Primary mechanisms for temephos resistance may vary between Ae. aegypti populations, yet also appear to support previous findings suggesting that multiple linked esterase genes may contribute to temephos resistance in the RecR strain as well as other populations. PMID:26576515

  10. Intrachromosomal Amplification, Locus Deletion and Point Mutation in the Aquaglyceroporin AQP1 Gene in Antimony Resistant Leishmania (Viannia) guyanensis

    PubMed Central

    Monte-Neto, Rubens; Laffitte, Marie-Claude N.; Leprohon, Philippe; Reis, Priscila; Frézard, Frédéric; Ouellette, Marc

    2015-01-01

    Background Antimony resistance complicates the treatment of infections caused by the parasite Leishmania. Methodology/Principal Findings Using next generation sequencing, we sequenced the genome of four independent Leishmania guyanensis antimony-resistant (SbR) mutants and found different chromosomal alterations including aneuploidy, intrachromosomal gene amplification and gene deletion. A segment covering 30 genes on chromosome 19 was amplified intrachromosomally in three of the four mutants. The gene coding for the multidrug resistance associated protein A involved in antimony resistance was also amplified in the four mutants, most likely through chromosomal translocation. All mutants also displayed a reduced accumulation of antimony mainly due to genomic alterations at the level of the subtelomeric region of chromosome 31 harboring the gene coding for the aquaglyceroporin 1 (LgAQP1). Resistance involved the loss of LgAQP1 through subtelomeric deletions in three mutants. Interestingly, the fourth mutant harbored a single G133D point mutation in LgAQP1 whose role in resistance was functionality confirmed through drug sensitivity and antimony accumulation assays. In contrast to the Leishmania subspecies that resort to extrachromosomal amplification, the Viannia strains studied here used intrachromosomal amplification and locus deletion. Conclusions/Significance This is the first report of a naturally occurred point mutation in AQP1 in antimony resistant parasites. PMID:25679388

  11. High-resolution mapping of the wheat Lr46 pleiotropic rust resistance locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rust diseases are the most important diseases of wheat globally, and genetic resistance is the most effective method for controlling all three rusts. Numerous resistance genes have been characterized and reported. For typical resistance genes, the mechanism of resistance and the basis of race specif...

  12. The environment exerts a greater influence than the transgene on the transcriptome of field-grown wheat expressing the Pm3b allele.

    PubMed

    Quijano, Carolina Diaz; Brunner, Susanne; Keller, Beat; Gruissem, Wilhelm; Sautter, Christof

    2015-02-01

    Wheat provides 20 % of the calories consumed worldwide. Powdery mildew infections of wheat can result in more than 30 % yield loss but it has been demonstrated that wheat overexpressing Pm3b, an allele of the R gene Pm3, has enhanced resistance against powdery mildew under field conditions. A gene expression profile study using GeneChip Wheat Genome Array and Fluidigm 96.96 Dynamic Arrays was performed to obtain insights into the mode of action of Pm3b and to elucidate the molecular basis of pleiotropic effects observed in three out of four independent transgenic events under field conditions. A cluster analysis of the microarray data and a principal component analysis of the Fluidigm 96.96 Dynamic Arrays data showed that transgenic lines and null segregants grouped together. The microarray analysis of samples from fungicide-treated plants revealed that significantly fewer genes were differentially expressed in Pm3b#1 than in Pm3b#2, which had a pleiotropic phenotype in the field, compared to their null segregants. Together, our data provide evidence that the environment influenced gene expression in the Pm3b lines more than the transgene itself. PMID:25095900

  13. Identification of a locus in arabidopsis controlling both the expression of rhizobacteria-mediated induced systemic resistance (ISR) and basal resistance against Pseudomonas syringae pv. tomato.

    PubMed

    Ton, J; Pieterse, C M; Van Loon, L C

    1999-10-01

    Selected nonpathogenic rhizobacteria with biological disease control activity are able to elicit an induced systemic resistance (ISR) response that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Ten ecotypes of Arabidopsis thaliana were screened for their potential to express rhizobacteria-mediated ISR and pathogen-induced SAR against the leaf pathogen Pseudomonas syringae pv. tomato DC3000 (Pst). All ecotypes expressed SAR. However, of the 10 ecotypes tested, ecotypes RLD and Wassilewskija (Ws) did not develop ISR after treatment of the roots with nonpathogenic Pseudomonas fluorescens WCS417r bacteria. This nonresponsive phenotype was associated with relatively high susceptibility to Pst infection. The F1 progeny of crosses between the non-responsive ecotypes RLD and Ws on the one hand, and the responsive ecotypes Columbia (Col) and Landsberg erecta (Ler) on the other hand, were fully capable of expressing ISR and exhibited a relatively high level of basal resistance, similar to that of their WCS417r-responsive parent. This indicates that the potential to express ISR and the relatively high level of basal resistance against Pst are both inherited as dominant traits. Analysis of the F2 and F3 progeny of a Col x RLD cross revealed that inducibility of ISR and relatively high basal resistance against Pst cosegregate in a 3:1 fashion, suggesting that both resistance mechanisms are monogenically determined and genetically linked. Neither the responsiveness to WCS417r nor the relatively high level of basal resistance against Pst were complemented in the F1 progeny of crosses between RLD and Ws, indicating that RLD and Ws are both affected in the same locus, necessary for the expression of ISR and basal resistance against Pst. The corresponding locus, designated ISR1, was mapped between markers B4 and GL1 on chromosome 3. The observed association between ISR and basal resistance against Pst suggests that rhizobacteria-mediated ISR

  14. Development of a novel strategy for fungal transformation based on a mutant locus conferring carboxin-resistance in Magnaporthe oryzae.

    PubMed

    Guo, Min; Zhu, Xiaolei; Li, Hongxia; Tan, Leyong; Pan, Yuemin

    2016-12-01

    The accurate manipulation of genomic integration of mutant alleles or fluorescent fusion-protein constructs is necessary for understanding of pathogenic mechanism of Magnaporthe oryzae. Recently, this can be achieved by integrating of exogenous DNA randomly into genome of this pathogen, but ectopic integration may result in alteration of gene expression or gene disruption due to unpredictable position effects and/or disruption of protein-coding regions. In this study, we establish a novel strategy for locus-specific integration of exogenous DNA via carboxin-resistance reconstitution by a point-mutation (H245L) on succinate dehydrogenase subunit Mosdi1. Independent transformants derived from the same reconstitution construct showed consistent fluorescent signal and undiversified phenotypes, including hyphae growth, conidiation and pathogenicity, in M. oryzae. Meanwhile, 96 % of all transformants integrate correctly into the Mosdi1 locus as a single copy. Furthermore, we provide a vector carrying yeast recombination cassette and thus allow assembly of multiple overlapping DNA fragments by yeast in vivo recombination for gene complementation and protein localization assay. PMID:27558019

  15. Drug-resistant tuberculosis can be predicted by Mycobacterial interspersed repetitive unit locus

    PubMed Central

    Yu-feng, Wen; Chao, Jiang; Xian-feng, Cheng

    2015-01-01

    It is unknown whether MIRU-VNTR (Mycobacterial Interspersed Repetitive Unit-Variable Number of Tandem Repeat) is associated with drug resistance of Mycobacterium tuberculosis. The purpose of this study was to explore the ability of 24 MIRU loci to predict the drug resistance of Isoniazid (INH), Rifampicin (RFP), Streptomycin (SM), Ethambutol (EMB) and Pyrazinamide (PZA). We collected the drug resistance and MIRU loci information of 109 strains of M. tuberculosis from an open database. The results of multivariate logistic regression showed that the VNTR polymorphism of MTUB04 was related to INH resistance [odds ratio (OR) = 2.82, P = 0.00], RFP resistance (OR = 1.91, P = 0.02), SM resistance (OR = 1.98, P = 0.01) and EMB resistance (OR = 1.95, P = 0.03). MIRU40 was associated with INH resistance (OR = 2.22, P = 0.00). MTUB21 was connected with INH resistance (OR = 1.63, P = 0.02) and SM resistance (OR = 1.69, P = 0.01). MIRU26 was correlated with SM resistance (OR = 1.52, P = 0.04). MIRU39 was associated with EMB resistance (OR = 4.07, P = 0.02). The prediction power of MIRU loci were 0.84, 0.70, 0.85, and 0.74 respectively for INH (predicted by MTUB04, MIRU20, and MTUB21), RFP (predicted by MTUB04), SM (predicted by MTUB21 and MIRU26) and EMB (MTUB04 and MIRU39) through ROC analysis. Our results showed that MIRU loci were related to anti-tuberculosis drug and could predict the drug resistance of tuberculosis. PMID:25759689

  16. A Mutation Causing Imidazolinone Resistance Maps to the Csr1 Locus of Arabidopsis thaliana.

    PubMed

    Haughn, G W; Somerville, C R

    1990-04-01

    A mutant of Arabidopsis thaliana, two hundred times more resistant to the imidazolinone herbicide imazapyr than wild-type plants, was isolated by direct selection of seedlings from a mutagenized population. Genetic analysis showed that resistance is due to a single dominant nuclear mutation that could not be separated by recombination from a mutation in the CSR1 gene encoding acetohydroxy acid synthase. Acetohydroxy acid synthase activity in extracts isolated from the mutant was 1000-fold more resistant to inhibition by imazapyr than that of the wild type. The resistant enzyme activity cosegregated with whole plant resistance. These data strongly suggest that the mutation is an allele of CSR1 encoding an imazapyr-resistant AHAS. PMID:16667374

  17. The wheat Sr50 gene reveals rich diversity at a cereal disease resistance locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We identify the wheat stem rust resistance gene Sr50 by physical mapping, mutation and complementation as homologous to barley Mla encoding a Coiled-Coil-Nucleotide-Binding-Leucine-Rich Repeat (CC-NB-LRR) protein. We show that Sr50 confers a unique resistance specificity, different from Sr31 and oth...

  18. Antisense expression of peach mildew resistance locus O (PpMlo1) gene confers cross-species resistance to powdery mildew in Fragaria x ananassa.

    PubMed

    Jiwan, Derick; Roalson, Eric H; Main, Dorrie; Dhingra, Amit

    2013-12-01

    Powdery mildew (PM) is one of the major plant pathogens. The conventional method of PM control includes frequent use of sulfur-based fungicides adding to production costs and potential harm to the environment. PM remains a major scourge for Rosaceae crops where breeding approaches mainly resort to gene-for-gene resistance. We have tested an alternate source of PM resistance in Rosaceae. Mildew resistance locus O (MLO) has been well studied in barley due to its role in imparting broad spectrum resistance to PM. We identified PpMlo1 (Prunus persica Mlo) in peach and characterized it further to test if a similar mechanism of resistance is conserved in Rosaceae. Due to its recalcitrance in tissue culture, reverse genetic studies involving PpMloI were not feasible in peach. Therefore, Fragaria x ananassa LF9 line, a taxonomic surrogate, was used for functional analysis of PpMlo1. Agrobacterium-mediated transformation yielded transgenic strawberry plants expressing PpMlo1 in sense and antisense orientation. Antisense expression of PpMlo1 in transgenic strawberry plants conferred resistance to Fragaria-specific powdery mildew, Podosphaera macularis. Phylogenetic analysis of 208 putative Mlo gene copies from 35 plant species suggests a large number of duplications of this gene family prior to the divergence of monocots and eudicots, early in eudicot diversification. Our results indicate that the Mlo-based resistance mechanism is functional in Rosaceae, and that Fragaria can be used as a host to test mechanistic function of genes derived from related tree species. To the best of our knowledge, this work is one of the first attempts at testing the potential of using a Mlo-based resistance strategy to combat powdery mildew in Rosaceae. PMID:23728780

  19. Identification of a new locus Ptr(t) required for rice blast resistance gene Pi-ta-mediated resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistance to the blast pathogen Magnaporthe oryzae is proposed to be initiated by physical binding of a putative cytoplasmic receptor encoded by a NBS-type resistance gene, Pi-ta, to the processed elicitor encoded by the corresponding avirulence gene AVR-Pita. Here we report the identification of a...

  20. Genetics of resistance to African trypanosomes: role of the H-2 locus in determining resistance to infection with Trypanosoma rhodesiense.

    PubMed Central

    Levine, R F; Mansfield, J M

    1981-01-01

    Susceptibility and resistance to Trypanosoma rhodesiense infections in inbred and H-2 congenic strains of mice were studied. Mean survival times and patterns of parasitemia were examined. C3HeB/FeJ mice were highly susceptible; CBA/J, A/J, and BALB/cByJ mice displayed an intermediate level of susceptibility; whereas C57BL/10 mice were highly resistant. H-2 congenic strains with the BL/10 background resembled the BL/10 parental type, thereby suggesting that the major histocompatibility complex does not play a major role in regulating resistance and susceptibility to infection with T. rhodesiense. PMID:7309237

  1. Exome and transcriptome sequencing of Aedes aegypti identifies a locus that confers resistance to Brugia malayi and alters the immune response.

    PubMed

    Juneja, Punita; Ariani, Cristina V; Ho, Yung Shwen; Akorli, Jewelna; Palmer, William J; Pain, Arnab; Jiggins, Francis M

    2015-03-01

    Many mosquito species are naturally polymorphic for their abilities to transmit parasites, a feature which is of great interest for controlling vector-borne disease. Aedes aegypti, the primary vector of dengue and yellow fever and a laboratory model for studying lymphatic filariasis, is genetically variable for its capacity to harbor the filarial nematode Brugia malayi. The genome of Ae. aegypti is large and repetitive, making genome resequencing difficult and expensive. We designed exome captures to target protein-coding regions of the genome, and used association mapping in a wild Kenyan population to identify a single, dominant, sex-linked locus underlying resistance. This falls in a region of the genome where a resistance locus was previously mapped in a line established in 1936, suggesting that this polymorphism has been maintained in the wild for the at least 80 years. We then crossed resistant and susceptible mosquitoes to place both alleles of the gene into a common genetic background, and used RNA-seq to measure the effect of this locus on gene expression. We found evidence for Toll, IMD, and JAK-STAT pathway activity in response to early stages of B. malayi infection when the parasites are beginning to die in the resistant genotype. We also found that resistant mosquitoes express anti-microbial peptides at the time of parasite-killing, and that this expression is suppressed in susceptible mosquitoes. Together, we have found that a single resistance locus leads to a higher immune response in resistant mosquitoes, and we identify genes in this region that may be responsible for this trait. PMID:25815506

  2. Exome and Transcriptome Sequencing of Aedes aegypti Identifies a Locus That Confers Resistance to Brugia malayi and Alters the Immune Response

    PubMed Central

    Juneja, Punita; Ariani, Cristina V.; Ho, Yung Shwen; Akorli, Jewelna; Palmer, William J.; Pain, Arnab; Jiggins, Francis M.

    2015-01-01

    Many mosquito species are naturally polymorphic for their abilities to transmit parasites, a feature which is of great interest for controlling vector-borne disease. Aedes aegypti, the primary vector of dengue and yellow fever and a laboratory model for studying lymphatic filariasis, is genetically variable for its capacity to harbor the filarial nematode Brugia malayi. The genome of Ae. aegypti is large and repetitive, making genome resequencing difficult and expensive. We designed exome captures to target protein-coding regions of the genome, and used association mapping in a wild Kenyan population to identify a single, dominant, sex-linked locus underlying resistance. This falls in a region of the genome where a resistance locus was previously mapped in a line established in 1936, suggesting that this polymorphism has been maintained in the wild for the at least 80 years. We then crossed resistant and susceptible mosquitoes to place both alleles of the gene into a common genetic background, and used RNA-seq to measure the effect of this locus on gene expression. We found evidence for Toll, IMD, and JAK-STAT pathway activity in response to early stages of B. malayi infection when the parasites are beginning to die in the resistant genotype. We also found that resistant mosquitoes express anti-microbial peptides at the time of parasite-killing, and that this expression is suppressed in susceptible mosquitoes. Together, we have found that a single resistance locus leads to a higher immune response in resistant mosquitoes, and we identify genes in this region that may be responsible for this trait. PMID:25815506

  3. Identification of a genetic locus responsible for antimicrobial peptide resistance in Clostridium difficile.

    PubMed

    McBride, Shonna M; Sonenshein, Abraham L

    2011-01-01

    Clostridium difficile causes chronic intestinal disease, yet little is understood about how the bacterium interacts with and survives in the host. To colonize the intestine and cause persistent disease, the bacterium must circumvent killing by host innate immune factors, such as cationic antimicrobial peptides (CAMPs). In this study, we investigated the effect of model CAMPs on growth and found that C. difficile is not only sensitive to these compounds but also responds to low levels of CAMPs by expressing genes that lead to CAMP resistance. By plating the bacterium on medium containing the CAMP nisin, we isolated a mutant capable of growing in three times the inhibitory concentration of CAMPs. This mutant also showed increased resistance to the CAMPs gallidermin and polymyxin B, demonstrating tolerance to different types of antimicrobial peptides. We identified the mutated gene responsible for the resistance phenotype as CD1352. This gene encodes a putative orphan histidine kinase that lies adjacent to a predicted ABC transporter operon (CD1349 to CD1351). Transcriptional analysis of the ABC transporter genes revealed that this operon was upregulated in the presence of nisin in wild-type cells and was more highly expressed in the CD1352 mutant. The insertional disruption of the CD1349 gene resulted in significant decreases in resistance to the CAMPs nisin and gallidermin but not polymyxin B. Because of their role in cationic antimicrobial peptide resistance, we propose the designation cprABC for genes CD1349 to CD1351 and cprK for the CD1352 gene. These results provide the first evidence of a C. difficile gene associated with antimicrobial peptide resistance. PMID:20974818

  4. Tumor progression locus 2 (TPL2) regulates obesity-associated inflammation and insulin resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Obesity-associated low-grade systemic inflammation resulting from increased adipose mass is strongly related to the development of insulin resistance and type 2 diabetes as well as other metabolic complications. Recent studies have demonstrated the obese metabolic state can be improved by ablating ...

  5. Leaf rust resistance in wheat line RL6062 is an allele at the Lr3 locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RL6062, a 'Thatcher' backcross line of wheat (Triticum aestivum L.) has resistance to leaf rust (caused by Puccinia triticina) derived from a line of common wheat from Iran. RL6062 has an intermediate infection type (IT) of small to moderate uredinia surrounded by distinct chlorosis. RL6062 was cros...

  6. Fine mapping of barley locus Rps6 conferring resistance to wheat stripe rust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major disease of wheat that is causing large economic losses in many wheat-growing regions of the world. Deployment of Pst resistance genes has been an effective strategy for controlling this pathogen, but many of these gen...

  7. Mutagenesis at the ouabain-resistance locus in human diploid fibroblasts.

    PubMed

    Buchwald, M

    1977-09-01

    The variables affecting the frequency of ouabain-resistant mutant clones have been studied in a strain of foetal lung fibroblasts. Optimum mutant recovery was obtained when cells were selected in 10(-6) M ouabain at a cell density of 2 X 10(4) cells/cm 2 (10(6) cell per 100-mm dish). The spontaneous mutation rate was estimated to be 4 X 10(-8) per cell generation. Treatment with the mutagens ethyl methanesulfonate (EMS), N-methyl-N' -nitro-N-nitrosoguanidine, and UV light increased the frequency of mutant colonies by an order of magnitude. The maximum number of mutants after mutagenesis with EMS occurred after two population doublings of growth in non-selective medium prior to selection and depended on the dose of EMS. Ouabain-resistance is a useful marker for studies of quantitative mutagenesis in human cells. PMID:904650

  8. Cloning and analysis of a locus (mcr) involved in mitomycin C resistance in Streptomyces lavendulae.

    PubMed Central

    August, P. R.; Flickinger, M. C.; Sherman, D. H.

    1994-01-01

    Two genes (mcrA and mcrB) from Streptomyces lavendulae that together confer resistance to mitomycin C were identified. This DNA appears to comprise a polycistronic operon with a drug-inducible leaderless mRNA. The deduced amino acid sequence of mcrA shows similarity to sequences of a special class of bacterial, plant, and animal oxygen oxidoreductases. Images PMID:7517396

  9. Receptor-like genes in the major resistance locus of lettuce are subject to divergent selection.

    PubMed Central

    Meyers, B C; Shen, K A; Rohani, P; Gaut, B S; Michelmore, R W

    1998-01-01

    Disease resistance genes in plants are often found in complex multigene families. The largest known cluster of disease resistance specificities in lettuce contains the RGC2 family of genes. We compared the sequences of nine full-length genomic copies of RGC2 representing the diversity in the cluster to determine the structure of genes within this family and to examine the evolution of its members. The transcribed regions range from at least 7.0 to 13.1 kb, and the cDNAs contain deduced open reading frames of approximately 5. 5 kb. The predicted RGC2 proteins contain a nucleotide binding site and irregular leucine-rich repeats (LRRs) that are characteristic of resistance genes cloned from other species. Unique features of the RGC2 gene products include a bipartite LRR region with >40 repeats. At least eight members of this family are transcribed. The level of sequence diversity between family members varied in different regions of the gene. The ratio of nonsynonymous (Ka) to synonymous (Ks) nucleotide substitutions was lowest in the region encoding the nucleotide binding site, which is the presumed effector domain of the protein. The LRR-encoding region showed an alternating pattern of conservation and hypervariability. This alternating pattern of variation was also found in all comparisons within families of resistance genes cloned from other species. The Ka /Ks ratios indicate that diversifying selection has resulted in increased variation at these codons. The patterns of variation support the predicted structure of LRR regions with solvent-exposed hypervariable residues that are potentially involved in binding pathogen-derived ligands. PMID:9811792

  10. Molecular genetic analysis of a locus required for resistance to antimicrobial peptides in Salmonella typhimurium.

    PubMed Central

    Parra-Lopez, C; Baer, M T; Groisman, E A

    1993-01-01

    The innate immunity of vertebrates and invertebrates to microbial infection is mediated in part by small cationic peptides with antimicrobial activity. Successful pathogens have evolved mechanisms to withstand the antibiotic activity of these molecules. We have isolated a set of genes from Salmonella typhimurium which are required for virulence and resistance to the antimicrobial peptides melittin and protamine. Sequence analysis of a 5.7 kb segment from the wild-type plasmid conferring resistance to protamine contained five open reading frames: sapA, sapB, sapC, sapD and sapF, organized in an operon structure and transcribed as a 5.3 kb mRNA. SapD and SapF exhibited similarity with the 'ATP binding cassette' family of transporters including the bacterial Opp and SpoOK, involved in the uptake of oligopeptides; the yeast STE6, necessary for the export of a peptide pheromone; and the mammalian mdr, which mediates resistance to chemotherapeutic agents in cancer cells. SapA showed identity with other periplasmic solute binding proteins involved in peptide transport. The SapABCDF system constitutes a novel transporter for enteric bacteria and the first one harboring a periplasmic component with a role in virulence. Images PMID:8223423

  11. Rapid, Transient Changes at the env Locus of Plasma Human Immunodeficiency Virus Type 1 Populations during the Emergence of Protease Inhibitor Resistance

    PubMed Central

    Delwart, Eric L.; Pan, Heng; Neumann, Avidan; Markowitz, Martin

    1998-01-01

    Plasma human immunodeficiency virus type 1 (HIV-1) populations were genetically analyzed at their most variable locus, the envelope gene, during the rapid emergence of resistance to protease inhibitor monotherapy. Plasma virus populations remained genetically constant prior to drug treatment and during the 1 to 2 weeks following initiation of therapy, while viremia fell 10- to 100-fold. Concomitant with rapid plasma viremia rebounds associated with the emergence of drug-resistant virus, marked alterations were then detected at the env locus. Plasma population changes lasted only a few weeks before the reappearance of the pretreatment envelope variants. The emergence of resistance to single protease inhibitors was therefore associated with major but transient changes at a nonselected locus. Selection for resistance to single protease inhibitors thus appears to be more complex than the continued replication of a large, random, and therefore genetically representative sampling of the pretreatment plasma population. The possibility that drug-privileged anatomical sites containing distinct envelope variants and/or a small effective HIV-1 population size account for these results is discussed. PMID:9499102

  12. Usefulness of double locus sequence typing (DLST) for regional and international epidemiological surveillance of methicilin-resistant Staphylococcus aureus.

    PubMed

    Basset, P; Senn, L; Prod'hom, G; Bille, J; Francioli, P; Zanetti, G; Blanc, D S

    2010-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections worldwide. To differentiate reliably among S. aureus isolates, we recently developed double locus sequence typing (DLST) based on the analysis of partial sequences of clfB and spa genes. In the present study, we evaluated the usefulness of DLST for epidemiological investigations of MRSA by routinely typing 1242 strains isolated in Western Switzerland. Additionally, particular local and international collections were typed by pulsed field gel electrophoresis (PFGE) and DLST to check the compatibility of DLST with the results obtained by PFGE, and for international comparisons. Using DLST, we identified the major MRSA clones of Western Switzerland, and demonstrated the close relationship between local and international clones. The congruence of 88% between the major PFGE and DLST clones indicated that our results obtained by DLST were compatible with earlier results obtained by PFGE. DLST could thus easily be incorporated in a routine surveillance procedure. In addition, the unambiguous definition of DLST types makes this method more suitable than PFGE for long-term epidemiological surveillance. Finally, the comparison of the results obtained by DLST, multilocus sequence typing, PFGE, Staphylococcal cassette chromosome mec typing and the detection of Panton-Valentine leukocidin genes indicated that no typing scheme should be used on its own. It is only the combination of data from different methods that gives the best chance of describing precisely the epidemiology and phylogeny of MRSA. PMID:19832717

  13. Comparative sequence analysis of the potato cyst nematode resistance locus H1 reveals a major lack of co-linearity between three haplotypes in potato (Solanum tuberosum ssp.).

    PubMed

    Finkers-Tomczak, Anna; Bakker, Erin; de Boer, Jan; van der Vossen, Edwin; Achenbach, Ute; Golas, Tomasz; Suryaningrat, Suwardi; Smant, Geert; Bakker, Jaap; Goverse, Aska

    2011-02-01

    The H1 locus confers resistance to the potato cyst nematode Globodera rostochiensis pathotypes 1 and 4. It is positioned at the distal end of chromosome V of the diploid Solanum tuberosum genotype SH83-92-488 (SH) on an introgression segment derived from S. tuberosum ssp. andigena. Markers from a high-resolution genetic map of the H1 locus (Bakker et al. in Theor Appl Genet 109:146-152, 2004) were used to screen a BAC library to construct a physical map covering a 341-kb region of the resistant haplotype coming from SH. For comparison, physical maps were also generated of the two haplotypes from the diploid susceptible genotype RH89-039-16 (S. tuberosum ssp. tuberosum/S. phureja), spanning syntenic regions of 700 and 319 kb. Gene predictions on the genomic segments resulted in the identification of a large cluster consisting of variable numbers of the CC-NB-LRR type of R genes for each haplotype. Furthermore, the regions were interspersed with numerous transposable elements and genes coding for an extensin-like protein and an amino acid transporter. Comparative analysis revealed a major lack of gene order conservation in the sequences of the three closely related haplotypes. Our data provide insight in the evolutionary mechanisms shaping the H1 locus and will facilitate the map-based cloning of the H1 resistance gene. PMID:21049265

  14. Multigeneic QTL: the laccase encoded within the soybean Rfs2/rhg1 locus inferred to underlie part of the dual resistance to cyst nematode and sudden death syndrome.

    PubMed

    Iqbal, M J; Ahsan, R; Afzal, A J; Jamai, A; Meksem, K; El-Shemy, H A; Lightfoot, D A

    2009-01-01

    Multigeneic QTL present significant problems to analysis. Resistance to soybean (Glycine max (L) Merr.) sudden death syndrome (SDS) caused by Fusarium virguliforme was partly underlain by QRfs2 that was clustered with, or pleiotropic to, the multigeneic rhg1 locus providing resistance to soybean cyst nematode (SCN; Heterodera glycines). A group of five genes were found between the two markers that delimited the Rfs2/rhg1 locus. One of the five genes was predicted to encode an unusual diphenol oxidase (laccase; EC 1.10.3.2). The aim of this study was to characterize this member of the soybean laccase gene-family and explore its involvement in SDS resistance. A genomic clone and a full length cDNA was isolated from resistant cultivar 'Forrest' that were different among susceptible cultivars 'Asgrow 3244' and 'Williams 82' at four residues R/H168, I/M271, R/H330, E/K470. Additional differences were found in six of the seven introns and the promoter region. Transcript abundance (TA) among genotypes that varied for resistance to SDS or SCN did not differ significantly. Therefore the protein activity was inferred to underlie resistance. Protein expressed in yeast pYES2/NTB had weak enzyme activity with common substrates but good activity with root phenolics. The Forrest isoform may underlie both QRfs2 and rhg1. PMID:19193960

  15. Evaluation of PM-3 Chemistry Data and Possible Interpretations of 3H Observations, Revision 0

    SciTech Connect

    Andrews, Robert; Marutzky, Sam J.

    2015-02-01

    This report summarizes the analyses of the groundwater results from sampling of PM-3-1 (deep) and PM-3-2 (shallow), with a particular focus of evaluating the groundwater geochemistry data in comparison to the geochemistry observed in other wells in the Thirsty Canyon area as well as to evaluate the potential source of 3H observed in these piezometers from previous sampling activities, which employed depth-discrete bailers or a Bennett submersible piston pump.

  16. Genetic Characterization of Resistance to Wheat Stem Rust Race TTKSK in Landrace and Wild Barley Accessions Identifies the rpg4/Rpg5 Locus.

    PubMed

    Mamo, Bullo Erena; Smith, Kevin P; Brueggeman, Robert S; Steffenson, Brian J

    2015-01-01

    Race TTKSK of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici) threatens the production of wheat and barley worldwide because of its broad-spectrum virulence on many widely grown cultivars. Sources of resistance against race TTKSK were recently identified in several barley landraces (Hordeum vulgare subsp. vulgare) and wild barley accessions (H. vulgare subsp. spontaneum). The objectives of this study were to characterize the inheritance of resistance to wheat stem rust race TTKSK in four barley landraces (Hv501, Hv545, Hv602, and Hv612) and two wild barley (WBDC213 and WBDC345) accessions, map the resistance genes, and determine the allelic relationships among the genes in these accessions and the previously described rpg4/Rpg5 locus. Resistant accessions were crossed with the susceptible cv. Steptoe and resulting F3 populations were evaluated for resistance to race TTKSK at the seedling stage. Segregation of F3 families in populations involving the resistance sources of Hv501, Hv545, Hv612, WBDC213, and WBDC345 fit a 1:2:1 ratio for homozygous resistant (HR)/segregating (SEG)/homozygous susceptible (HS) progenies (with χ2=2.27 to 5.87 and P=0.053 to 0.321), indicating that a single gene confers resistance to race TTKSK. Segregation of F3 families in cross Steptoe/Hv602 did not fit a 1:2:1 ratio (HR/SEG/HS of 20:47:43 with χ2=11.95 and P=0.003), indicating that more than one gene is involved in imparting resistance to race TTKSK. Bulked segregant analysis using >1,500 single-nucleotide polymorphism markers positioned a resistance locus in all six populations on chromosome 5HL in very close proximity to the known location of the rpg4/Rpg5 complex locus. Allelism tests were conducted by making crosses among resistant accessions Hv501, Hv545, and Hv612 and also Q21861 with the rpg4/Rpg5 complex. No segregation was observed in F2 families inoculated with race TTKSK, demonstrating that all Hv lines carry the same allele for resistance and that it

  17. Molecular Cloning and Functional Analysis of UV RESISTANCE LOCUS 8 (PeUVR8) from Populus euphratica

    PubMed Central

    Mao, Ke; Wang, Lina; Li, Yuan-Yuan; Wu, Rongling

    2015-01-01

    Ultraviolet-B (UV-B; 280–315 nm) light, which is an integral part of the solar radiation reaching the surface of the Earth, induces a broad range of physiological responses in plants. The UV RESISTANCE LOCUS 8 (UVR8) protein is the first and only light photoreceptor characterized to date that is specific for UV-B light and it regulates various aspects of plant growth and development in response to UV-B light. Despite its involvement in the control of important plant traits, most studies on UV-B photoreceptors have focused on Arabidopsis and no data on UVR8 function are available for forest trees. In this study, we isolated a homologue of the UV receptor UVR8 of Arabidopsis, PeUVR8, from Populus euphratica (Euphrates poplar) and analyzed its structure and function in detail. The deduced PeUVR8 amino acid sequence contained nine well-conserved regulator of chromosome condensation 1 (RCC1) repeats and the region 27 amino acids from the C terminus (C27) that interact with COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC1). Secondary and tertiary structure analysis showed that PeUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis thaliana. Using heterologous expression in Arabidopsis, we showed that PeUVR8 overexpression rescued the uvr8 mutant phenotype. In addition, PeUVR8 overexpression in wild-type background seedlings grown under UV-B light inhibited hypocotyl elongation and enhanced anthocyanin accumulation. Furthermore, we examined the interaction between PeUVR8 and AtCOP1 using a bimolecular fluorescence complementation (BiFC) assay. Our data provide evidence that PeUVR8 plays important roles in the control of photomorphogenesis in planta. PMID:26171608

  18. Role of the locus coeruleus in enhanced orexin A-induced spontaneous physical activity in obesity-resistant rats

    PubMed Central

    Perez-Leighton, Claudio E.; Billington, Charles J.; Kotz, Catherine M.

    2013-01-01

    Orexin/hypocretin terminals innervate noradrenergic locus coeruleus (LC) neurons that project to the prefrontral cortex, which may influence spontaneous physical activity (SPA) and energy balance. Obesity-resistant (OR) rats have higher orexin receptors (OXR) mRNA in the LC and other brain regions, as well as lower adiposity compared with obese rats. These findings led us to hypothesize that orexin activity in the LC is relevant for the OR phenotype. We compared OR rats to Sprague-Dawley rats. We predicted that: 1) brain OXR expression pattern is sufficient to differentiate OR from non-bred Sprague-Dawley rats; 2) nonresting energy expenditure (NREE) and orexin A (OXA)-stimulated SPA after injection in LC would be greater in OR rats; and 3) the effect of OXA on SPA would be greater than its effect on feeding. OXR mRNA from 11 brain sites and the SPA and feeding responses to OXA in the LC were determined. Body composition, basal SPA, and EE were determined. Principal component analysis of the OXR expression pattern differentiates OR and Sprague-Dawley rats and suggests the OXR mRNA in the LC is important in defining the OR phenotype. Compared with Sprague-Dawley rats, OR rats had greater SPA and NREE and lower resting EE and adiposity. SPA responsivity to OXA in the LC was greater in OR rats compared with Sprague-Dawley rats. OXA in the LC did not stimulate feeding in OR or Sprague-Dawley rats. These data suggest that the LC is a prominent site modulating OXA-stimulated SPA, which promotes lower adiposity and higher nonresting EE. PMID:24089383

  19. Analysis of a plant complex resistance gene locus underlying immune-related hybrid incompatibility and its occurrence in nature.

    PubMed

    Alcázar, Rubén; von Reth, Marcel; Bautor, Jaqueline; Chae, Eunyoung; Weigel, Detlef; Koornneef, Maarten; Parker, Jane E

    2014-12-01

    Mechanisms underlying speciation in plants include detrimental (incompatible) genetic interactions between parental alleles that incur a fitness cost in hybrids. We reported on recessive hybrid incompatibility between an Arabidopsis thaliana strain from Poland, Landsberg erecta (Ler), and many Central Asian A. thaliana strains. The incompatible interaction is determined by a polymorphic cluster of Toll/interleukin-1 receptor-nucleotide binding-leucine rich repeat (TNL) RPP1 (Recognition of Peronospora parasitica1)-like genes in Ler and alleles of the receptor-like kinase Strubbelig Receptor Family 3 (SRF3) in Central Asian strains Kas-2 or Kond, causing temperature-dependent autoimmunity and loss of growth and reproductive fitness. Here, we genetically dissected the RPP1-like Ler locus to determine contributions of individual RPP1-like Ler (R1-R8) genes to the incompatibility. In a neutral background, expression of most RPP1-like Ler genes, except R3, has no effect on growth or pathogen resistance. Incompatibility involves increased R3 expression and engineered R3 overexpression in a neutral background induces dwarfism and sterility. However, no individual RPP1-like Ler gene is sufficient for incompatibility between Ler and Kas-2 or Kond, suggesting that co-action of at least two RPP1-like members underlies this epistatic interaction. We find that the RPP1-like Ler haplotype is frequent and occurs with other Ler RPP1-like alleles in a local population in Gorzów Wielkopolski (Poland). Only Gorzów individuals carrying the RPP1-like Ler haplotype are incompatible with Kas-2 and Kond, whereas other RPP1-like alleles in the population are compatible. Therefore, the RPP1-like Ler haplotype has been maintained in genetically different individuals at a single site, allowing exploration of forces shaping the evolution of RPP1-like genes at local and regional population scales. PMID:25503786

  20. Molecular Cloning and Functional Analysis of UV RESISTANCE LOCUS 8 (PeUVR8) from Populus euphratica.

    PubMed

    Mao, Ke; Wang, Lina; Li, Yuan-Yuan; Wu, Rongling

    2015-01-01

    Ultraviolet-B (UV-B; 280-315 nm) light, which is an integral part of the solar radiation reaching the surface of the Earth, induces a broad range of physiological responses in plants. The UV RESISTANCE LOCUS 8 (UVR8) protein is the first and only light photoreceptor characterized to date that is specific for UV-B light and it regulates various aspects of plant growth and development in response to UV-B light. Despite its involvement in the control of important plant traits, most studies on UV-B photoreceptors have focused on Arabidopsis and no data on UVR8 function are available for forest trees. In this study, we isolated a homologue of the UV receptor UVR8 of Arabidopsis, PeUVR8, from Populus euphratica (Euphrates poplar) and analyzed its structure and function in detail. The deduced PeUVR8 amino acid sequence contained nine well-conserved regulator of chromosome condensation 1 (RCC1) repeats and the region 27 amino acids from the C terminus (C27) that interact with COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC1). Secondary and tertiary structure analysis showed that PeUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis thaliana. Using heterologous expression in Arabidopsis, we showed that PeUVR8 overexpression rescued the uvr8 mutant phenotype. In addition, PeUVR8 overexpression in wild-type background seedlings grown under UV-B light inhibited hypocotyl elongation and enhanced anthocyanin accumulation. Furthermore, we examined the interaction between PeUVR8 and AtCOP1 using a bimolecular fluorescence complementation (BiFC) assay. Our data provide evidence that PeUVR8 plays important roles in the control of photomorphogenesis in planta. PMID:26171608

  1. Transfer of the Rsv3 locus from ‘Harosoy’ for resistance to soybean mosaic virus strains C and D in Japan

    PubMed Central

    Kato, Shin; Takada, Yoshitake; Shimamura, Satoshi; Hirata, Kaori; Sayama, Takashi; Taguchi-Shiobara, Fumio; Ishimoto, Masao; Kikuchi, Akio; Nishio, Takeshi

    2016-01-01

    Resistance to soybean mosaic virus (SMV) is imperative for soybean (Glycine max (L.) Merr.) production in the Tohoku region. Molecular markers for SMV resistance were previously reported for U.S. SMV strains, but they cannot be applied because of the differences in strain classification between Japan and the U.S. A U.S. variety ‘Harosoy’ has been used mainly as a donor of resistance to SMV strains C and D in a Japanese breeding program, resulting in resistant varieties such as ‘Fukuibuki.’ Because ‘Harosoy’ harbors the Rsv3 gene conferring resistance to the virulent SMV strain groups, G5 through G7, it appears that the Rsv3 gene confers resistance to strains C and D. In this study, we introduced resistance to the two strains from ‘Fukuibuki’ into a leading variety ‘Ohsuzu’ by recurrent backcrossing with marker-assisted selection. All lines selected with markers near Rsv3 showed resistance to the strains, suggesting that the Rsv3 locus is responsible for the resistance. Three years of trials showed that one of the breeding lines, ‘Tohoku 169,’ was equivalent to ‘Ohsuzu’ with respect to agricultural characteristics such as seed size, maturity date, and seed yield, except for the SMV resistance. PMID:27162503

  2. Genomic and Transcriptomic Associations Identify a New Insecticide Resistance Phenotype for the Selective Sweep at the Cyp6g1 Locus of Drosophila melanogaster.

    PubMed

    Battlay, Paul; Schmidt, Joshua M; Fournier-Level, Alexandre; Robin, Charles

    2016-01-01

    Scans of the Drosophila melanogaster genome have identified organophosphate resistance loci among those with the most pronounced signature of positive selection. In this study, the molecular basis of resistance to the organophosphate insecticide azinphos-methyl was investigated using the Drosophila Genetic Reference Panel, and genome-wide association. Recently released full transcriptome data were used to extend the utility of the Drosophila Genetic Reference Panel resource beyond traditional genome-wide association studies to allow systems genetics analyses of phenotypes. We found that both genomic and transcriptomic associations independently identified Cyp6g1, a gene involved in resistance to DDT and neonicotinoid insecticides, as the top candidate for azinphos-methyl resistance. This was verified by transgenically overexpressing Cyp6g1 using natural regulatory elements from a resistant allele, resulting in a 6.5-fold increase in resistance. We also identified four novel candidate genes associated with azinphos-methyl resistance, all of which are involved in either regulation of fat storage, or nervous system development. In Cyp6g1, we find a demonstrable resistance locus, a verification that transcriptome data can be used to identify variants associated with insecticide resistance, and an overlap between peaks of a genome-wide association study, and a genome-wide selective sweep analysis. PMID:27317781

  3. Genomic and Transcriptomic Associations Identify a New Insecticide Resistance Phenotype for the Selective Sweep at the Cyp6g1 Locus of Drosophila melanogaster

    PubMed Central

    Battlay, Paul; Schmidt, Joshua M.; Fournier-Level, Alexandre; Robin, Charles

    2016-01-01

    Scans of the Drosophila melanogaster genome have identified organophosphate resistance loci among those with the most pronounced signature of positive selection. In this study, the molecular basis of resistance to the organophosphate insecticide azinphos-methyl was investigated using the Drosophila Genetic Reference Panel, and genome-wide association. Recently released full transcriptome data were used to extend the utility of the Drosophila Genetic Reference Panel resource beyond traditional genome-wide association studies to allow systems genetics analyses of phenotypes. We found that both genomic and transcriptomic associations independently identified Cyp6g1, a gene involved in resistance to DDT and neonicotinoid insecticides, as the top candidate for azinphos-methyl resistance. This was verified by transgenically overexpressing Cyp6g1 using natural regulatory elements from a resistant allele, resulting in a 6.5-fold increase in resistance. We also identified four novel candidate genes associated with azinphos-methyl resistance, all of which are involved in either regulation of fat storage, or nervous system development. In Cyp6g1, we find a demonstrable resistance locus, a verification that transcriptome data can be used to identify variants associated with insecticide resistance, and an overlap between peaks of a genome-wide association study, and a genome-wide selective sweep analysis. PMID:27317781

  4. Genetics and Molecular Mapping of Black Rot Resistance Locus Xca1bc on Chromosome B-7 in Ethiopian Mustard (Brassica carinata A. Braun).

    PubMed

    Sharma, Brij Bihari; Kalia, Pritam; Yadava, Devendra Kumar; Singh, Dinesh; Sharma, Tilak Raj

    2016-01-01

    Black rot caused by Xanthomonas campestris pv. campestris (Pam.) Dowson is the most destructive disease of cauliflower causing huge loss to the farmers throughout the world. Since there are limited sources of resistance to black rot in B. oleracea (C genome Brassica), exploration of A and B genomes of Brassica was planned as these were thought to be potential reservoirs of black rot resistance gene(s). In our search for new gene(s) for black rot resistance, F2 mapping population was developed in Brassica carinata (BBCC) by crossing NPC-17, a susceptible genotype with NPC-9, a resistant genotype. Out of 364 Intron length polymorphic markers and microsatellite primers used in this study, 41 distinguished the parental lines. However, resistant and susceptible bulks could be distinguished by three markers At1g70610, SSR Na14-G02 and At1g71865 which were used for genotyping of F2 mapping population. These markers were placed along the resistance gene, according to order, covering a distance of 36.30 cM. Intron length polymorphic markers At1g70610 and At1g71865 were found to be linked to black rot resistance locus (Xca1bc) at 6.2 and 12.8 cM distance, respectively. This is the first report of identification of markers linked to Xca1bc locus in Brassica carinata on B-7 linkage group. Intron length polymorphic markers provided a novel and attractive option for marker assisted selection due to high cross transferability and cost effectiveness for marker assisted alien gene introgression into cauliflower. PMID:27023128

  5. Genetics and Molecular Mapping of Black Rot Resistance Locus Xca1bc on Chromosome B-7 in Ethiopian Mustard (Brassica carinata A. Braun)

    PubMed Central

    Sharma, Brij Bihari; Kalia, Pritam; Yadava, Devendra Kumar; Singh, Dinesh; Sharma, Tilak Raj

    2016-01-01

    Black rot caused by Xanthomonas campestris pv. campestris (Pam.) Dowson is the most destructive disease of cauliflower causing huge loss to the farmers throughout the world. Since there are limited sources of resistance to black rot in B. oleracea (C genome Brassica), exploration of A and B genomes of Brassica was planned as these were thought to be potential reservoirs of black rot resistance gene(s). In our search for new gene(s) for black rot resistance, F2 mapping population was developed in Brassica carinata (BBCC) by crossing NPC-17, a susceptible genotype with NPC-9, a resistant genotype. Out of 364 Intron length polymorphic markers and microsatellite primers used in this study, 41 distinguished the parental lines. However, resistant and susceptible bulks could be distinguished by three markers At1g70610, SSR Na14-G02 and At1g71865 which were used for genotyping of F2 mapping population. These markers were placed along the resistance gene, according to order, covering a distance of 36.30 cM. Intron length polymorphic markers At1g70610 and At1g71865 were found to be linked to black rot resistance locus (Xca1bc) at 6.2 and 12.8 cM distance, respectively. This is the first report of identification of markers linked to Xca1bc locus in Brassica carinata on B-7 linkage group. Intron length polymorphic markers provided a novel and attractive option for marker assisted selection due to high cross transferability and cost effectiveness for marker assisted alien gene introgression into cauliflower. PMID:27023128

  6. Quinolone resistance locus nfxD of Escherichia coli is a mutant allele of the parE gene encoding a subunit of topoisomerase IV.

    PubMed Central

    Breines, D M; Ouabdesselam, S; Ng, E Y; Tankovic, J; Shah, S; Soussy, C J; Hooper, D C

    1997-01-01

    The locus nfxD, which contributes to high-level quinolone resistance in Escherichia coli KF111b (gyrAr nfxB nfxD), is only expressed in the presence of a gyrA mutation, and maps to the region of the parC and parE genes, was outcrossed into strain KF130, creating strain DH161 (gyrAr nfxD). DNA sequence analysis of DH161 revealed no changes in the topoisomerase IV parC quinolone resistance-determining region but did identify a single T-to-A mutation in parE at codon 445, leading to a change from Leu to His. Full-length cloned parE+ partially complemented the resistance phenotype in KF111b and DH161, but did not complement the resistance phenotype in strain KF130 (gyrAr). No complementation was seen with cloned, truncated parE+. To confirm these findings, gyrAr was first outcrossed from KF130 into E. coli W3110parE10 [parE temperature sensitive(Ts)] and KL16. The transduced strains KL16 and W3110parE10 were subsequently transformed with plasmids containing cloned parE from DH161 or KL16. Cloned parE from DH161 increased norfloxacin resistance in the parE(Ts) background twofold at 30 degrees C and fourfold at 42 degrees C compared to those for cloned parE from KL16. The same experiment with a non-Ts background revealed a twofold increase in the norfloxacin MIC at both 30 and 42 degrees C. These data identify the nfxD conditional resistance locus as a mutant allele of parE. This report is the first of a quinolone-resistant parE mutant and confirms the role of topoisomerase IV as a secondary target of norfloxacin in E. coli. PMID:8980775

  7. Chimerization at the AQP2-AQP3 locus is the genetic basis of melarsoprol-pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates.

    PubMed

    Graf, Fabrice E; Baker, Nicola; Munday, Jane C; de Koning, Harry P; Horn, David; Mäser, Pascal

    2015-08-01

    Aquaglyceroporin-2 is a known determinant of melarsoprol-pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2-AQP3 tandem locus was described from melarsoprol-pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2-aqp3 null T. b. brucei does not. This proves that AQP2-AQP3 chimerization is the cause of melarsoprol-pentamidine cross-resistance in the T. b. gambiense isolates. PMID:26042196

  8. Adaptation of Trypanosoma rhodesiense to hypohaptoglobinaemic serum requires transcription of the APOL1 resistance gene in a RNA polymerase I locus.

    PubMed

    Lecordier, Laurence; Uzureau, Pierrick; Tebabi, Patricia; Brauner, Jonathan; Benghiat, Fleur Samantha; Vanhollebeke, Benoit; Pays, Etienne

    2015-08-01

    Human apolipoprotein L1 (APOL1) kills African trypanosomes except Trypanosoma rhodesiense and Trypanosoma gambiense, the parasites causing sleeping sickness. APOL1 uptake into trypanosomes is favoured by its association with the haptoglobin-related protein-haemoglobin complex, which binds to the parasite surface receptor for haptoglobin-haemoglobin. As haptoglobin-haemoglobin can saturate the receptor, APOL1 uptake is increased in haptoglobin-poor (hypohaptoglobinaemic) serum (HyHS). While T. rhodesiense resists APOL1 by RNA polymerase I (pol-I)-mediated expression of the serum resistance-associated (SRA) protein, T. gambiense resists by pol-II-mediated expression of the T. gambiense-specific glycoprotein (TgsGP). Moreover, in T. gambiense resistance to HyHS is linked to haptoglobin-haemoglobin receptor inactivation by mutation. We report that unlike T. gambiense, T. rhodesiense possesses a functional haptoglobin-haemoglobin receptor, and that like T. gambiense experimentally provided with active receptor, this parasite is killed in HyHS because of receptor-mediated APOL1 uptake. However, T. rhodesiense could adapt to low haptoglobin by increasing transcription of SRA. When assayed in Trypanosoma brucei, resistance to HyHS occurred with pol-I-, but not with pol-II-mediated SRA expression. Similarly, T. gambiense provided with active receptor acquired resistance to HyHS only when TgsGP was moved to a pol-I locus. Thus, transcription by pol-I favours adaptive gene regulation, explaining the presence of SRA in a pol-I locus. PMID:25899052

  9. Inheritance and Identification of a Major Quantitative Trait Locus (QTL) that Confers Resistance to Meloidogyne incognita and a Novel QTL for Plant Height in Sweet Sorghum.

    PubMed

    Harris-Shultz, Karen R; Davis, Richard F; Knoll, Joseph E; Anderson, William; Wang, Hongliang

    2015-12-01

    Southern root-knot nematodes (Meloidogyne incognita) are a pest on many economically important row crop and vegetable species and management relies on chemicals, plant resistance, and cultural practices such as crop rotation. Little is known about the inheritance of resistance to M. incognita or the genomic regions associated with resistance in sorghum (Sorghum bicolor). In this study, an F2 population (n = 130) was developed between the resistant sweet sorghum cultivar 'Honey Drip' and the susceptible sweet cultivar 'Collier'. Each F2 plant was phenotyped for stalk weight, height, juice Brix, root weight, total eggs, and eggs per gram of root. Strong correlations were observed between eggs per gram of root and total eggs, height and stalk weight, and between two measurements of Brix. Genotyping-by-sequencing was used to generate single nucleotide polymorphism markers. The G-Model, single marker analysis, interval mapping, and composite interval mapping were used to identify a major quantitative trait locus (QTL) on chromosome 3 for total eggs and eggs per gram of root. Furthermore, a new QTL for plant height was also discovered on chromosome 3. Simple sequence repeat markers were developed in the total eggs and eggs per gram of root QTL region and the markers flanking the resistance gene are 4.7 and 2.4 cM away. These markers can be utilized to move the southern root-knot nematode resistance gene from Honey Drip to any sorghum line. PMID:26574655

  10. Combined linkage and association mapping reveals candidates for Scmv1, a major locus involved in resistance to sugarcane mosaic virus (SCMV) in maize

    PubMed Central

    2013-01-01

    Background Sugarcane mosaic virus (SCMV) disease causes substantial losses of grain yield and forage biomass in susceptible maize cultivars. Maize resistance to SCMV is associated with two dominant genes, Scmv1 and Scmv2, which are located on the short arm of chromosome 6 and near the centromere region of chromosome 3, respectively. We combined both linkage and association mapping to identify positional candidate genes for Scmv1. Results Scmv1 was fine-mapped in a segregating population derived from near-isogenic lines and further validated and fine-mapped using two recombinant inbred line populations. The combined results assigned the Scmv1 locus to a 59.21-kb interval, and candidate genes within this region were predicted based on the publicly available B73 sequence. None of three predicted genes that are possibly involved in the disease resistance response are similar to receptor-like resistance genes. Candidate gene–based association mapping was conducted using a panel of 94 inbred lines with variable resistance to SCMV. A presence/absence variation (PAV) in the Scmv1 region and two polymorphic sites around the Zmtrx-h gene were significantly associated with SCMV resistance. Conclusion Combined linkage and association mapping pinpoints Zmtrx-h as the most likely positional candidate gene for Scmv1. These results pave the way towards cloning of Scmv1 and facilitate marker-assisted selection for potyvirus resistance in maize. PMID:24134222

  11. Construction of a reference linkage map of Vitis amurensis and genetic mapping of Rpv8, a locus conferring resistance to grapevine downy mildew.

    PubMed

    Blasi, Paule; Blanc, Sophie; Wiedemann-Merdinoglu, Sabine; Prado, Emilce; Rühl, Ernst H; Mestre, Pere; Merdinoglu, Didier

    2011-06-01

    Downy mildew, caused by the oomycete Plasmopara viticola, is one of the major threats to grapevine. All traditional cultivars of grapevine (Vitis vinifera) are susceptible to downy mildew, the control of which requires regular application of fungicides. In contrast, many sources of resistance to P. viticola have been described in the Vitis wild species, among which is V. amurensis Rupr. (Vitaceae), a species originating from East Asia. A genetic linkage map of V. amurensis, based on 122 simple sequence repeat and 6 resistance gene analogue markers, was established using S1 progeny. This map covers 975 cM on 19 linkage groups, which represent 82% of the physical coverage of the V. vinifera reference genetic map. To measure the general level of resistance, the sporulation of P. viticola and the necrosis produced in response to infection, five quantitative and semi-quantitative parameters were scored 6 days post-inoculation on the S1 progeny. A quantitative trait locus (QTL) analysis allowed us to identify on linkage group 14 a major QTL controlling the resistance to downy mildew found in V. amurensis, which explained up to 86.3% of the total phenotypic variance. This QTL was named 'Resistance to Plasmopara viticola 8' (Rpv8). PMID:21404060

  12. A reference genetic map of Muscadinia rotundifolia and identification of Ren5, a new major locus for resistance to grapevine powdery mildew.

    PubMed

    Blanc, Sophie; Wiedemann-Merdinoglu, Sabine; Dumas, Vincent; Mestre, Pere; Merdinoglu, Didier

    2012-12-01

    Muscadinia rotundifolia, a species closely related to cultivated grapevine Vitis vinifera, is a major source of resistance to grapevine downy and powdery mildew, two major threats to cultivated traditional cultivars of V. vinifera respectively caused by the oomycete Plasmopara viticola and the ascomycete Erisyphe necator. The aim of the present work was to develop a reference genetic linkage map based on simple sequence repeat (SSR) markers for M. rotundifolia. This map was created using S1 M. rotundifolia cv. Regale progeny, and covers 948 cM on 20 linkage groups, which corresponds to the expected chromosome number for muscadine. The comparison of the genetic maps of V. vinifera and M. rotundifolia revealed a high macrosynteny between the genomes of both species. The S1 progeny was used to assess the general level of resistance of M. rotundifolia to P. viticola and E. necator, by scoring different parameters of pathogen development. A quantitative trait locus (QTL) analysis allowed us to highlight a major QTL on linkage group 14 controlling resistance to powdery mildew, which explained up to 58 % of the total phenotypic variance. This QTL was named 'Resistance to Erysiphe Necator 5' (Ren5). A microscopic evaluation E. necator mycelium development on resistant and susceptible genotypes of the S1 progeny showed that Ren5 exerts its action after the formation of the first appressorium, and acts by delaying, and then stopping, mycelium development. PMID:22865124

  13. Genetic resistance to soybean rust in PI 567099A is at or near the Rpp3 locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research identified soybean accession PI 567099A as resistant to soybean rust (SBR). The objective of this research was to map the resistance genes(s) of PI 567099A. A population segregating for SBR resistance was evaluated in the 2008 and 2009 seasons in Paraguay. In both seasons F2:3 f...

  14. NDR1, a locus of Arabidopsis thaliana that is required for disease resistance to both a bacterial and a fungal pathogen.

    PubMed Central

    Century, K S; Holub, E B; Staskawicz, B J

    1995-01-01

    We have employed Arabidopsis thaliana as a model host plant to genetically dissect the molecular pathways leading to disease resistance. A. thaliana accession Col-0 is susceptible to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 but resistant in a race-specific manner to DC3000 carrying any one of the cloned avirulence genes avrB, avrRpm1, avrRpt2, and avrPph3. Fast-neutron-mutagenized Col-0 M2 seed was screened to identify mutants susceptible to DC3000(avrB). Disease assays and analysis of in planta bacterial growth identified one mutant, ndr1-1 (nonrace-specific disease resistance), that was susceptible to DC3000 expressing any one of the four avirulence genes tested. Interestingly, a hypersensitive-like response was still induced by several of the strains. The ndr1-1 mutation also rendered the plant susceptible to several avirulent isolates of the fungal pathogen Peronospora parasitica. Genetic analysis of ndr1-1 demonstrated that the mutation segregated as a single recessive locus, located on chromosome III. Characterization of the ndr1-1 mutation suggests that a common step exists in pathways of resistance to two unrelated pathogens. Images Fig. 1 PMID:11607554

  15. Identification of Stmm3 locus Conferring Resistance to Late-stage Chemically Induced Skin Papillomas on Mouse Chromosome 4 by Congenic Mappingand Allele-specific Alteration Analysis

    PubMed Central

    Saito, Megumi; Okumura, Kazuhiro; Miura, Ikuo; Wakana, Shigeharu; Kominami, Ryo; Wakabayashi, Yuichi

    2014-01-01

    Genome-wide association studies have revealed that many low-penetrance cancer susceptibility loci are located throughout the genome; however, a very limited number of genes have been identified so far. Using a forward genetics approach to map such loci in a mouse skin cancer model, we previously identified strong genetic loci conferring resistance to chemically induced skin papillomas on chromosome 4 and 7 with a large number of [(FVB/N × MSM/Ms) F1 × FVB/N] backcross mice. In this report, we describe a combination of congenic mapping and allele-specific alteration analysis of the loci on chromosome 4. We used linkage analysis and a congenic mouse strain, FVB.MSM-Stmm3 to refine the location of Stmm3 (Skin tumor modifier of MSM 3) locus within a physical interval of about 34 Mb on distal chromosome 4. In addition, we used patterns of allele-specific imbalances in tumors from N2 and N10 congenic mice to narrow down further the region of Stmm3 locus to a physical distance of about 25 Mb. Furthermore, immunohistochemical analysis showed papillomas from congenic mice had less proliferative activity. These results suggest that Stmm3 responsible genes may have an influence on papilloma formation in the two-stage skin carcinogenesis by regulating papilloma growth rather than development. PMID:25077764

  16. Arabidopsis thaliana DM2h (R8) within the Landsberg RPP1-like Resistance Locus Underlies Three Different Cases of EDS1-Conditioned Autoimmunity

    PubMed Central

    Garcia, Ana V.; Wagner, Christine; Choudhury, Sayan R.; Wang, Yiming; James, Geo Velikkakam; Griebel, Thomas; Alcázar, Ruben; Tsuda, Kenichi; Schneeberger, Korbinian; Parker, Jane E.

    2016-01-01

    Plants have a large panel of nucleotide-binding/leucine rich repeat (NLR) immune receptors which monitor host interference by diverse pathogen molecules (effectors) and trigger disease resistance pathways. NLR receptor systems are necessarily under tight control to mitigate the trade-off between induced defenses and growth. Hence, mis-regulated NLRs often cause autoimmunity associated with stunting and, in severe cases, necrosis. Nucleocytoplasmic ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) is indispensable for effector-triggered and autoimmune responses governed by a family of Toll-Interleukin1-Receptor-related NLR receptors (TNLs). EDS1 operates coincidently or immediately downstream of TNL activation to transcriptionally reprogram cells for defense. We show here that low levels of nuclear-enforced EDS1 are sufficient for pathogen resistance in Arabidopsis thaliana, without causing negative effects. Plants expressing higher nuclear EDS1 amounts have the genetic, phenotypic and transcriptional hallmarks of TNL autoimmunity. In a screen for genetic suppressors of nuclear EDS1 autoimmunity, we map multiple, independent mutations to one gene, DM2h, lying within the polymorphic DANGEROUS MIX2 cluster of TNL RPP1-like genes from A. thaliana accession Landsberg erecta (Ler). The DM2 locus is a known hotspot for deleterious epistatic interactions leading to immune-related incompatibilities between A. thaliana natural accessions. We find that DM2hLer underlies two further genetic incompatibilities involving the RPP1-likeLer locus and EDS1. We conclude that the DM2hLer TNL protein and nuclear EDS1 cooperate, directly or indirectly, to drive cells into an immune response at the expense of growth. A further conclusion is that regulating the available EDS1 nuclear pool is fundamental for maintaining homeostatic control of TNL immune pathways. PMID:27082651

  17. Arabidopsis thaliana DM2h (R8) within the Landsberg RPP1-like Resistance Locus Underlies Three Different Cases of EDS1-Conditioned Autoimmunity.

    PubMed

    Stuttmann, Johannes; Peine, Nora; Garcia, Ana V; Wagner, Christine; Choudhury, Sayan R; Wang, Yiming; James, Geo Velikkakam; Griebel, Thomas; Alcázar, Ruben; Tsuda, Kenichi; Schneeberger, Korbinian; Parker, Jane E

    2016-04-01

    Plants have a large panel of nucleotide-binding/leucine rich repeat (NLR) immune receptors which monitor host interference by diverse pathogen molecules (effectors) and trigger disease resistance pathways. NLR receptor systems are necessarily under tight control to mitigate the trade-off between induced defenses and growth. Hence, mis-regulated NLRs often cause autoimmunity associated with stunting and, in severe cases, necrosis. Nucleocytoplasmic ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) is indispensable for effector-triggered and autoimmune responses governed by a family of Toll-Interleukin1-Receptor-related NLR receptors (TNLs). EDS1 operates coincidently or immediately downstream of TNL activation to transcriptionally reprogram cells for defense. We show here that low levels of nuclear-enforced EDS1 are sufficient for pathogen resistance in Arabidopsis thaliana, without causing negative effects. Plants expressing higher nuclear EDS1 amounts have the genetic, phenotypic and transcriptional hallmarks of TNL autoimmunity. In a screen for genetic suppressors of nuclear EDS1 autoimmunity, we map multiple, independent mutations to one gene, DM2h, lying within the polymorphic DANGEROUS MIX2 cluster of TNL RPP1-like genes from A. thaliana accession Landsberg erecta (Ler). The DM2 locus is a known hotspot for deleterious epistatic interactions leading to immune-related incompatibilities between A. thaliana natural accessions. We find that DM2hLer underlies two further genetic incompatibilities involving the RPP1-likeLer locus and EDS1. We conclude that the DM2hLer TNL protein and nuclear EDS1 cooperate, directly or indirectly, to drive cells into an immune response at the expense of growth. A further conclusion is that regulating the available EDS1 nuclear pool is fundamental for maintaining homeostatic control of TNL immune pathways. PMID:27082651

  18. The Type 2 Diabetes and Insulin-Resistance Locus Near IRS1 Is A Determinant of HDL Cholesterol and Triglycerides Levels Among Diabetic Subjects

    PubMed Central

    Sharma, Rajani; Prudente, Sabrina; Andreozzi, Francesco; Powers, Christine; Mannino, Gaia; Bacci, Simonetta; Gervino, Ernest V.; Hauser, Thomas H.; Succurro, Elena; Mercuri, Luana; Goheen, Elizabeth H.; Shah, Hetal; Trischitta, Vincenzo; Sesti, Giorgio; Doria, Alessandro

    2011-01-01

    OBJECTIVE SNP rs2943641 near the insulin receptor substrate 1 (IRS1) gene has been found to be associated with type 2 diabetes (T2D) and insulin-resistance in genome-wide association studies. We investigated whether this SNP is associated with cardiovascular risk factors and coronary artery disease (CAD) among diabetic individuals. METHODS SNP rs2943641 was typed in 2,133 White T2D subjects and tested for association with BMI, serum HDL cholesterol and triglycerides, hypertension history, and CAD risk. RESULTS HDL cholesterol decreased by 1 mg/dl (p=0.0045) and serum triglycerides increased by 6 mg/dl (p=0.018) for each copy of the insulin-resistance allele. Despite these effects, no association was found with increased CAD risk (OR=1.00, 95% CI 0.88–1.13). CONCLUSIONS The insulin-resistance and T2D locus near the IRS1 gene is a determinant of lower HDL cholesterol among T2D subjects. However, this effect is small and does not translate into a detectable increase in CAD risk in this population. PMID:21353221

  19. Reniform nematode (Rotylenchulus reniformis) resistance locus from Gossypium aridum identified and introgressed into upland cotton (G. hirsutum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    SSR markers associated with reniform nematode (Rotylenchulus reniformis) resistance were identified and mapped using progeny from a cross between a tri-species hybrid [Gossypium arboreum × (G 371 - G. hirsutum × G. aridum -)] and G. hirsutum MD51ne. The 50 most resistant and 26 most susceptible prog...

  20. A conserved locus conditioning Soil-borne wheat mosaic virus resistance on 5DL in common wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-borne wheat mosaic virus (SBWMV) is considered one of the most important diseases in winter wheat regions of the central and southeastern United States. Utilization of resistant cultivars is the only practical and environmentally friendly means of control. To identify QTL for SBWMV resistance, ...

  1. Construction of a genetic map based on high-throughput SNP genotyping and genetic mapping of a TuMV resistance locus in Brassica rapa.

    PubMed

    Chung, Hee; Jeong, Young-Min; Mun, Jeong-Hwan; Lee, Soo-Seong; Chung, Won-Hyong; Yu, Hee-Ju

    2014-04-01

    Brassica rapa is a member of the Brassicaceae family and includes vegetables and oil crops that are cultivated worldwide. The introduction of durable resistance against turnip mosaic virus (TuMV) into agronomically important cultivars has been a significant challenge for genetic and horticultural breeding studies of B. rapa. Based on our previous genome-wide analysis of DNA polymorphisms between the TuMV-resistant doubled haploid (DH) line VC40 and the TuMV-susceptible DH line SR5, we constructed a core genetic map of the VCS-13M DH population, which is composed of 83 individuals derived from microspore cultures of a F1 cross between VC40 and SR5, by analyzing the segregation of 314 sequence-characterized genetic markers. The genetic markers correspond to 221 SNPs and 31 InDels of genes as well as 62 SSRs, covering 1,115.9 cM with an average distance of 3.6 cM between the adjacent marker loci. The alignment and orientation of the constructed map showed good agreement with the draft genome sequence of Chiifu, thus providing an efficient strategy to map genic sequences. Using the genetic map, a novel dominant TuMV resistance locus (TuMV-R) in the VCS-13M DH population was identified as a 0.34 Mb region in the short arm of chromosome A6 in which four CC-NBS-LRR resistance genes and two pathogenesis-related-1 genes reside. The genetic map developed in this study can play an important role in the genetic study of TuMV resistance and the molecular breeding of B. rapa. PMID:24326528

  2. Quantitative trait locus responsible for resistance to Aphanomyces root rot (black root) caused by Aphanomyces cochlioides Drechs. in sugar beet.

    PubMed

    Taguchi, Kazunori; Ogata, Naoki; Kubo, Tomohiko; Kawasaki, Shinji; Mikami, Tetsuo

    2009-01-01

    Aphanomyces root rot, caused by Aphanomyces cochlioides Drechs., is one of the most serious diseases of sugar beet (Beta vulgaris L.). Identification and characterization of resistance genes is a major task in sugar beet breeding. To ensure the effectiveness of marker-assisted screening for Aphanomyces root rot resistance, genetic analysis of mature plants' phenotypic and molecular markers' segregation was carried out. At a highly infested field site, some 187 F(2) and 66 F(3) individuals, derived from a cross between lines 'NK-310mm-O' (highly resistant) and 'NK-184mm-O' (susceptible), were tested, over two seasons, for their level of resistance to Aphanomyces root rot. This resistance was classified into six categories according to the extent and intensity of whole plant symptoms. Simultaneously, two selected RAPD and 159 'NK-310mm-O'-coupled AFLP were used in the construction of a linkage map of 695.7 cM. Each of nine resultant linkage groups was successfully anchored to one of nine sugar beet chromosomes by incorporating 16 STS markers. Combining data for phenotype and molecular marker segregation, a single QTL was identified on chromosome III. This QTL explained 20% of the variance in F(2) population (in the year 2002) and 65% in F(3) lines (2003), indicating that this QTL plays a major role in the Aphanomyces root rot resistance. This is the first report of the genetic mapping of resistance to Aphanomyces-caused diseases in sugar beet. PMID:18813904

  3. THE Bct-1 LOCUS FOR RESISTANCE TO BEET CURLY TOP VIRUS IS ASSOCIATED WITH QUANTITATIVE RESISTANCE TO BEAN DWARF MOSAIC VIRUS IN COMMON BEAN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host resistance provides effective control of some diseases induced by geminiviruses in common bean. A recessive gene bgm-1 conditions resistance to Bean golden yellow mosaic virus (BGYMV) and is located on linkage group B3 near the bc-12 gene for resistance to Bean common mosaic virus. The dominan...

  4. Quantitative trait locus mapping and functional genomics of an organophosphate resistance trait in the western corn rootworm, Diabrotica virgifera virgifera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The western corn rootworm (WCR), Diabrotica virgifera virgifera, is an insect pest of corn, and population suppression with chemical insecticides is an important management tool. Traits conferring organophosphate insecticide resistance have increased in frequency among WCR populations, resulting in...

  5. The development of a PM3 parameter set to describe iron-sulfur proteins

    NASA Astrophysics Data System (ADS)

    Sundararajan, Mahesh; McNamara, Jonathan P.; Hillier, Ian H.; Wang, Hong; Burton, Neil A.

    2005-03-01

    A PM3 parameter set for iron has been developed, which is appropriate for the active site of iron sulfur proteins having a single iron atom by fitting DFT data obtained for a redox site analogue. These parameters are then tested on a set of such analogues involving a variety of ligands, and show good agreement with both DFT and experimental data for these species. The use of these parameters within a two level ONIOM treatment of the protein rubredoxin, yields accurate predictions of the effect of the enzyme on both Fe-S bond lengths and inner sphere reorganization energies.

  6. Effects of Introgression and Recombination on Haplotype Structure and Linkage Disequilibrium Surrounding a Locus Encoding Bymovirus Resistance in Barley

    PubMed Central

    Stracke, Silke; Presterl, Thomas; Stein, Nils; Perovic, Dragan; Ordon, Frank; Graner, Andreas

    2007-01-01

    We present a detailed analysis of linkage disequilibrium (LD) in the physical and genetic context of the barley gene Hv-eIF4E, which confers resistance to the barley yellow mosaic virus (BYMV) complex. Eighty-three SNPs distributed over 132 kb of Hv-eIF4E and six additional fragments genetically mapped to its flanking region were used to derive haplotypes from 131 accessions. Three haplogroups were recognized, discriminating between the alleles rym4 and rym5, which each encode for a spectrum of resistance to BYMV. With increasing map distance, haplotypes of susceptible genotypes displayed diverse patterns driven mainly by recombination, whereas haplotype diversity within the subgroups of resistant genotypes was limited. We conclude that the breakdown of LD within 1 cM of the resistance gene was generated mainly by susceptible genotypes. Despite the LD decay, a significant association between haplotype and resistance to BYMV was detected up to a distance of 5.5 cM from the resistance gene. The LD pattern and the haplotype structure of the target chromosomal region are the result of interplay between low recombination and recent breeding history. PMID:17151251

  7. Duplication of the A17L Locus of Vaccinia Virus Provides an Alternate Route to Rifampin Resistance

    PubMed Central

    Erlandson, Karl J.; Cotter, Catherine A.; Charity, James C.; Martens, Craig; Fischer, Elizabeth R.; Ricklefs, Stacy M.; Porcella, Stephen F.

    2014-01-01

    ABSTRACT Specific gene duplications can enable double-stranded DNA viruses to adapt rapidly to environmental pressures despite the low mutation rate of their high-fidelity DNA polymerases. We report on the rapid positive selection of a novel vaccinia virus genomic duplication mutant in the presence of the assembly inhibitor rifampin. Until now, all known rifampin-resistant vaccinia virus isolates have contained missense mutations in the D13L gene, which encodes a capsid-like scaffold protein required for stabilizing membrane curvature during the early stage of virion assembly. Here we describe a second pathway to rifampin resistance involving A17, a membrane protein that binds and anchors D13 to the immature virion. After one round of selection, a rifampin-resistant virus that contained a genomic duplication in the A17L-A21L region was recovered. The mutant had both C-terminally truncated and full-length A17L open reading frames. Expression of the truncated A17 protein was retained when the virus was passaged in the presence of rifampin but was lost in the absence of the drug, suggesting that the duplication decreased general fitness. Both forms of A17 were bound to the virion membrane and associated with D13. Moreover, insertion of an additional truncated or inducible full-length A17L open reading frame into the genome of the wild-type virus was sufficient to confer rifampin resistance. In summary, this report contains the first evidence of an alternate mechanism for resistance of poxviruses to rifampin, indicates a direct relationship between A17 levels and the resistance phenotype, and provides further evidence of the ability of double-stranded DNA viruses to acquire drug resistance through gene duplication. IMPORTANCE The present study provides the first evidence of a new mechanism of resistance of a poxvirus to the antiviral drug rifampin. In addition, it affirms the importance of the interaction between the D13 scaffold protein and the A17 membrane protein

  8. Genetic evidence for a product of the Fv-1 locus that transfers resistance to mouse leukemia viruses.

    PubMed Central

    Tennant, R W; Schluter, B; Myer, F E; Otten, J A; Yang, W K; Brown, A

    1976-01-01

    Extracts of mouse cells have been shown to transfer to N- or B-trophic host range types of mouse leukemia viruses. The genetic specificity of the inhibition was tested in two ways: (i) by correlating the Fv-1 genotype of a number of mouse strains with the restriction-transferring activity of extracts of the respective embryo cell cultures, and (ii) by correlating the Fv-1 genotype of BLC3F2 (C57BL/6 female [Fv-1bb] by C3H male [Fv-1nn] parental strains) mouse embryos, which segregate the Fv-1 alleles in a 12:1 ratio, with the inhibitor activity of extracts of the cells from each embryo. Five independent matings, totaling 45 individual embryos, were tested. Each embryo was cultured, and the Fv-1 genotype was determined independently by titration of N- and B-tropic viruses; the extracts of replicate secondary cultures were tested for their effect on infection of permissive cells by N- and B-tropic viruses. The specific-restriction-transferring activity of the embryos was found to segregate with the appropriate Fv-1 genotype. These res-lts confirm the suggestion that the inhibitor of the leukemia virus host range types in the cellular extracts is a product of the Fv-1 locus. PMID:186636

  9. Unexpected sequence types in livestock associated methicillin-resistant Staphylococcus aureus (MRSA): MRSA ST9 and a single locus variant of ST9 in pig farming in China.

    PubMed

    Wagenaar, Jaap A; Yue, Hua; Pritchard, Jane; Broekhuizen-Stins, Marian; Huijsdens, Xander; Mevius, Dik J; Bosch, Thijs; Van Duijkeren, Engeline

    2009-11-18

    In October 2008 nine farrow-to-finish pig farms were visited in Shuangliu County in Sichuan Province, China. One farm was empty for one month but not cleaned after depopulation. Dust samples were collected at each farm and analysed for the presence of methicillin-resistant Staphylococcus aureus (MRSA). Dust samples from four farms were also analysed for the presence of methicillin-susceptible S. aureus (MSSA). On 5/9 farms MRSA was isolated and on 2/4 farms MSSA was isolated. On two farms, including the empty farm, no MRSA or MSSA could be detected. All MRSA isolates (n=43) belonged to spa type t899. MSSA isolates belonged to spa type t899 (n=12) and spa type t034 (n=2). From 4/9 farms the MRSA isolates of spa type t899 were assigned to multilocus sequence type (MLST) ST9 whereas on one farm the MRSA spa type t899 isolates belonged to a single locus variant of MLST ST9 (ST1376). MSSA isolates with spa type t899 belonged to MLST ST9 and the MSSA with spa type t034 belonged to MLST ST398. This is the first report on MRSA in pig farms in China and the first time that MRSA ST9 and a single locus variant of ST9 are detected in pig farms. This study shows that livestock associated MRSA is not restricted to clonal lineage ST398 as found in Europe and Northern America in commercial pigs but that other MRSA lineages are able to spread in livestock as well. The study confirms that livestock may act as a reservoir for MRSA. PMID:19608357

  10. Microfluidic-chip-based multiple-locus variable-number tandem-repeat fingerprinting with new primer sets for methicillin-resistant Staphylococcus aureus.

    PubMed

    Sabat, Artur J; Chlebowicz, Monika A; Grundmann, Hajo; Arends, Jan P; Kampinga, Greetje; Meessen, Nico E L; Friedrich, Alexander W; van Dijl, Jan Maarten

    2012-07-01

    The detection of outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) infections and a rapid and accurate identification of sources and routes of transmission should be conducted in hospital settings as early and swiftly as possible. In this study, we investigated the application potential of a new approach based on multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and microfluidics technology for a rapid discrimination of MRSA lineages in outbreak settings. A total of 206 nonrepetitive MRSA isolates recovered from infected patients at the University Medical Center Groningen between 2000 and 2010 were tested. The results obtained by MLVF using microcapillary electrophoresis with newly designed primers were compared to those obtained by spa typing and multiple-locus variable-number tandem-repeat analysis (MLVA). The discriminatory power was 0.980 (107 patterns), 0.969 (85 allelic profiles), and 0.959 (66 types) for MLVF, MLVA, and spa typing, respectively. All methods tested showed a good concordance of results calculated by the adjusted Rand's coefficient method. Comparisons of data obtained by the three approaches allowed us to propose an 88% cutoff value for the similarity between any two MLVF patterns, which can be used in S. aureus epidemiological studies, including analyses of outbreaks and strain transmission events. Of the three tested methods, MLVF is the cheapest, fastest, and easiest to perform. MLVF applied to microfluidic polymer chips is a rapid, cheap, reproducible, and highly discriminating tool to determine the clonality of MRSA isolates and to trace the spread of MRSA strains over periods of many years. Although spa typing should be used due to its portability of data, MLVF has a high added value because it is more discriminatory. PMID:22573591

  11. Mutants resistant to anti-microtubule herbicides map to a locus on the uni linkage group in Chlamydomonas reinhardtii

    SciTech Connect

    James, S.W.; Ranum, L.P.W.; Silflow, C.D.; Lefebvre, P.A.

    1988-01-01

    The authors have used genetic analysis to study the mode of action of two anti-microtubule herbicides, amiprophos-methyl (APM) and oryzaline (ORY). Over 200 resistant mutants were selected by growth on APM- or ORY-containing plates. The 21 independently isolated mutants examined in this study are 3- to 8-fold resistant to APM and are strongly cross-resistant to ORY and butamiphos, a close analog of APM. Two Mendelian genes, apm1 and apm2, are defined by linkage and complementation analysis. There are 20 alleles of apm1 and one temperature-sensitive lethal (33/sup 0/) allele of apm2. Mapping by two-factor crosses places apm1 6.5 cM centromere proximal to uni1 and within 4 cM of pf7 on the uni linkage group, a genetically circular linkage group comprising genes which affect flagellar assembly or function; apm2 maps near the centromere of linkage group VIII. Allele-specific synthetic lethality is observed in crosses between amp2 and alleles of apm1. Also, self crosses of apm2 are zygotic lethal, whereas crosses of nine apm1 alleles inter se result in normal germination and tetrad viability. The mutants are recessive to their wild-type alleles but doubly heterozygous diploids (apm1 +/+ apm2) made with apm2 and any of 15 apm1 alleles display partial intergenic noncomplementation, expressed as intermediate resistance. Diploids homozygous for mutant alleles of apm1 are 4-6-fold resistant to APM and ORY; diploids homozygous for apm2 are ts/sup -/ and 2-fold resistant to the herbicides. From the results described the authors suggest that the gene products of apm1 and apm2 may interact directly or function in the same structure or process.

  12. A single dominant locus Ren4 confers non-race-specific penetration resistance to grapevine powdery mildew.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most powdery mildew resistance genes act after formation of the haustorial feeding cell and secretion of effector proteins into the host epidermis, enabling some degree of hyphal growth. The few genes identified to-date that act to prevent penetration, haustorial formation, and hyphal growth are, w...

  13. Quantitative trait locus analysis of Verticillium wilt resistance in an introgressed recombinant inbred population of Upland cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verticillium wilt (VW) of Upland cotton (Gossypium hirsutum L.) is caused by the soil-borne fungal pathogen Verticillium dahlia Kleb. The availability of VW-resistant cultivars is vital for control of this economically important disease, but there is a paucity of Upland cotton breeding lines and cul...

  14. Sequence variation at the rice blast resistance gene Pi-km locus: Implications for the development of allele specific markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recently cloned blast resistance (R) gene Pi-km protects rice crops against specific races of the fungal pathogen Magnaporthe oryzae in a gene-for-gene manner. The use of blast R genes remains the most cost-effective method for an integrated disease management strategy. To facilitate rice breed...

  15. FaRXf1: a locus conferring resistance to angular leaf spot caused by Xanthomonas fragariae in octoploid strawberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Angular leaf spot caused by Xanthomonas fragariae is the only major bacterial disease of cultivated strawberry (Fragaria ×ananassa). While this disease may cause reductions of up to 8 % of marketable yield in Florida winter annual production, no resistant cultivars have been commercialized. Wild acc...

  16. Fine Mapping and Isolation of Rmc1(blb)Locus to Columbia Root-Knot Nematode Resistance from Solanum bulbocastanum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Columbia root-knot nematode (Meloidogyne chitwoodi) causes a severe disease on potato in the Northwest of the US and other parts of the World. The natural resistance has been discovered in several wild potato species, Solanum bulbocastanum, S. hougasii and S. fendleri, endemic to Mexico and the ...

  17. Resistance locus pyramids alter transcript abundance in soybean roots inoculated with Fusarium solani f.sp. glycines.

    PubMed

    Iqbal, M J; Yaegashi, S; Njiti, V N; Ahsan, R; Cryder, K L; Lightfoot, D A

    2002-11-01

    Soybean Sudden Death Syndrome (SDS) is caused by Fusarium solani f.sp. glycines (Fsg). Six quantitative trait loci (QTLs), each conferring partial resistance to SDS, have been discovered in an Essex x Forrest recombinant inbred line (RIL) population, but their mode of action is not clear. This study aimed to identify genes (ESTs) whose mRNA transcripts were altered in abundance in soybean roots following inoculation of Fsg. Roots of the soybean variety Forrest (four resistance alleles) were inoculated with Fsg, and 14 days later RNA sequences that were differentially expressed relative to uninoculated roots were enriched using suppression subtraction and differential display. The abundance of these RNAs was quantified in inoculated and non-inoculated roots by macroarray hybridizations. A unigene set of 135 ESTs was identified and used in a further macroarray analysis. The abundance of 28 cDNA fragments was increased more than two-fold in inoculated compared to uninoculated roots of RIL 23 (six resistance alleles). In Forrest and Essex (two resistance alleles), the level of only one mRNA was increased two-fold in inoculated roots compared to the uninoculated roots. In Essex most of the mRNAs analyzed decreased in abundance (61/135 showed a two-fold decrease), while in Forrest most mRNA abundances did not change. Among the 28 cDNAs that revealed a two-fold or higher increase in mRNA abundance in RIL 23, 14% code for proteins known to be involved in plant defense, 21% in metabolism, 14% in cell structure and 4% in transport. Unannotated ESTs accounted for 43% of the genes, and 4% of the sequences were previously unknown. The plant defense-related genes that showed a differential response to Fsg inoculation suggested a role for the phenylproponoid pathway in soybean defense against Fsg. In Essex, genes involved in plant defense, cell wall synthesis, ethylene synthesis and metabolism were expressed at lower levels in inoculated roots. The difference in response between

  18. The Cmv1 host resistance locus is closely linked to the Ly49 multigene family within the natural killer cell gene complex on mouse chromosome 6

    SciTech Connect

    Forbes, C.A.; Shellam, G.R.; Scalzo, A.A.

    1997-05-01

    Natural killer (NK) cells play important roles in controlling tumor cells and against a range of infectious organisms. Recent studies of mouse NK cell surface receptors, which may be involved in the specificity of NK cells, have shown that many of these molecules are encoded by the Ly49 and Ly55 (Nkrp1) multigene families that map to distal mouse chromosome 6. Also mapping to this NK cell gene complex (NKC) is the resistance locus, Cmv1, which is involved in genetically determined resistance to murine cytomegalovirus (MCMV). The aim of this study was to localize Cmv1 more precisely in relation to other NKC loci by generating a high-resolution genetic map of the region. We have analyzed 1250 backcross mice comprising panels of 700 (BALB/c x C57BL/6J)F{sub 1} X BALB/c and 550 (A/J X C57BL/6J)F{sub 1} X A/J progeny. A total of 25 polymorphic genes or microsatellite markers were analyzed over a region of 10 map units from D6Mit134 to D6Mit59. The Cmv1 phenotypes of mice recombinant in this interval were tested by infection with MCMV. The results obtained indicate that the functionally important NKC region is a tightly linked cluster of loci spanning at least 0.4 map units. Furthermore, Cmv1 maps distal to, but very closely linked to, the Ly49 multigene family (< 0.2 map units), suggesting that MCMV resistance may be conferred by MHC class I-specific NK cell receptors. 49 refs., 4 figs., 1 tab.

  19. Applications of the PM3 semi-empirical method to the study of triethylenediamine.

    PubMed

    Mancuso, J; McEachern, R J

    1997-04-01

    Charcoal filters impregnated with triethylenediamine (TEDA) are known to be efficient for the collection of volatile methyl iodide, which may be released under a hypothetical loss-of-coolant accident in a nuclear generating station. The structure and thermodynamic stability of the products of the TEDA-methyl iodide reaction have thus been studied using semi-empirical techniques. The reaction of TEDA with two molecules of methyl iodide leads to a quaternization reaction at each of the nitrogens. Moreover, it is shown that substitution of the hydrogens on TEDA with electron-donating groups can lead to enhanced stability of the quaternary ammonium reaction products. The semi-empirical method PM3 (Parametric Method 3) was used as the basis for all calculations. Molecular systems and simulations were constructed using HyperChem 4.5 for Silicon Graphics workstations. Enthalpy determination and geometry optimization were some of the calculations performed on a system. PMID:9385556

  20. Genetic dissection of a TIR-NB-LRR locus from the wild North American grapevine species Muscadinia rotundifolia identifies paralogous genes conferring resistance to major fungal and oomycete pathogens in cultivated grapevine.

    PubMed

    Feechan, Angela; Anderson, Claire; Torregrosa, Laurent; Jermakow, Angelica; Mestre, Pere; Wiedemann-Merdinoglu, Sabine; Merdinoglu, Didier; Walker, Amanda R; Cadle-Davidson, Lance; Reisch, Bruce; Aubourg, Sebastien; Bentahar, Nadia; Shrestha, Bipna; Bouquet, Alain; Adam-Blondon, Anne-Françoise; Thomas, Mark R; Dry, Ian B

    2013-11-01

    The most economically important diseases of grapevine cultivation worldwide are caused by the fungal pathogen powdery mildew (Erysiphe necator syn. Uncinula necator) and the oomycete pathogen downy mildew (Plasmopara viticola). Currently, grapegrowers rely heavily on the use of agrochemicals to minimize the potentially devastating impact of these pathogens on grape yield and quality. The wild North American grapevine species Muscadinia rotundifolia was recognized as early as 1889 to be resistant to both powdery and downy mildew. We have now mapped resistance to these two mildew pathogens in M. rotundifolia to a single locus on chromosome 12 that contains a family of seven TIR-NB-LRR genes. We further demonstrate that two highly homologous (86% amino acid identity) members of this gene family confer strong resistance to these unrelated pathogens following genetic transformation into susceptible Vitis vinifera winegrape cultivars. These two genes, designated resistance to Uncinula necator (MrRUN1) and resistance to Plasmopara viticola (MrRPV1) are the first resistance genes to be cloned from a grapevine species. Both MrRUN1 and MrRPV1 were found to confer resistance to multiple powdery and downy mildew isolates from France, North America and Australia; however, a single powdery mildew isolate collected from the south-eastern region of North America, to which M. rotundifolia is native, was capable of breaking MrRUN1-mediated resistance. Comparisons of gene organization and coding sequences between M. rotundifolia and the cultivated grapevine V. vinifera at the MrRUN1/MrRPV1 locus revealed a high level of synteny, suggesting that the TIR-NB-LRR genes at this locus share a common ancestor. PMID:24033846

  1. High-resolution melting analysis of the spa locus reveals significant diversity within sequence type 93 methicillin-resistant Staphylococcus aureus from northern Australia.

    PubMed

    Tong, S Y C; Lilliebridge, R A; Holt, D C; McDonald, M I; Currie, B J; Giffard, P M

    2009-12-01

    High-resolution melting analysis is an inherently robust, easy and inexpensive approach to the examination of genomic regions containing single-nucleotide polymorphisms and hypervariable loci. Staphylococcus aureus sequence type (ST) 93 is a singleton, Panton-Valentine leukocidin-positive clone unique to Australia. A high-resolution melting-based method for the identification of ST93 was developed, and a similar approach was used to reveal diversity within the spa locus of this lineage. Statistical and graphical methods that account for instrumental and operator-dependent variation in high-resolution melting curves were developed, to allow greater confidence and reproducibility in deciding whether another curve is truly different from the baseline curve of an amplicon with known sequence. The data support a very early acquisition, or multiple independent acquisitions, of SCCmec by ST93 methicillin-susceptible S. aureus (MSSA), and the coexistence of MSSA and methicillin-resistant S. aureus versions of the same lineage within northern Australia. PMID:19392885

  2. Role of Arabidopsis UV RESISTANCE LOCUS 8 in plant growth reduction under osmotic stress and low levels of UV-B.

    PubMed

    Fasano, Rossella; Gonzalez, Nathalie; Tosco, Alessandra; Dal Piaz, Fabrizio; Docimo, Teresa; Serrano, Ramon; Grillo, Stefania; Leone, Antonella; Inzé, Dirk

    2014-05-01

    In high-light environments, plants are exposed to different types of stresses, such as an excess of UV-B, but also drought stress which triggers a common morphogenic adaptive response resulting in a general reduction of plant growth. Here, we report that the Arabidopsis thaliana UV RESISTANCE LOCUS 8 (UVR8) gene, a known regulator of the UV-B morphogenic response, was able to complement a Saccharomyces cerevisiae osmo-sensitive mutant and its expression was induced after osmotic or salt stress in Arabidopsis plants. Under low levels of UV-B, plants overexpressing UVR8 are dwarfed with a reduced root development and accumulate more flavonoids compared to control plants. The growth defects are mainly due to the inhibition of cell expansion. The growth inhibition triggered by UVR8 overexpression in plants under low levels of UV-B was exacerbated by mannitol-induced osmotic stress, but it was not significantly affected by ionic stress. In contrast, uvr8-6 mutant plants do not differ from wild-type plants under standard conditions, but they show an increased shoot growth under high-salt stress. Our data suggest that UVR8-mediated accumulation of flavonoid and possibly changes in auxin homeostasis are the underlying mechanism of the observed growth phenotypes and that UVR8 might have an important role for integrating plant growth and stress signals. PMID:24413416

  3. Multiple Roles for UV RESISTANCE LOCUS8 in Regulating Gene Expression and Metabolite Accumulation in Arabidopsis under Solar Ultraviolet Radiation1[W][OA

    PubMed Central

    Morales, Luis O.; Brosché, Mikael; Vainonen, Julia; Jenkins, Gareth I.; Wargent, Jason J.; Sipari, Nina; Strid, Åke; Lindfors, Anders V.; Tegelberg, Riitta; Aphalo, Pedro J.

    2013-01-01

    Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280–315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315–400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV. PMID:23250626

  4. A 1,681-locus consensus genetic map of cultivated cucumber including 67 NB-LRR resistance gene homolog and ten gene loci

    PubMed Central

    2013-01-01

    Background Cucumber is an important vegetable crop that is susceptible to many pathogens, but no disease resistance (R) genes have been cloned. The availability of whole genome sequences provides an excellent opportunity for systematic identification and characterization of the nucleotide binding and leucine-rich repeat (NB-LRR) type R gene homolog (RGH) sequences in the genome. Cucumber has a very narrow genetic base making it difficult to construct high-density genetic maps. Development of a consensus map by synthesizing information from multiple segregating populations is a method of choice to increase marker density. As such, the objectives of the present study were to identify and characterize NB-LRR type RGHs, and to develop a high-density, integrated cucumber genetic-physical map anchored with RGH loci. Results From the Gy14 draft genome, 70 NB-containing RGHs were identified and characterized. Most RGHs were in clusters with uneven distribution across seven chromosomes. In silico analysis indicated that all 70 RGHs had EST support for gene expression. Phylogenetic analysis classified 58 RGHs into two clades: CNL and TNL. Comparative analysis revealed high-degree sequence homology and synteny in chromosomal locations of these RGH members between the cucumber and melon genomes. Fifty-four molecular markers were developed to delimit 67 of the 70 RGHs, which were integrated into a genetic map through linkage analysis. A 1,681-locus cucumber consensus map including 10 gene loci and spanning 730.0 cM in seven linkage groups was developed by integrating three component maps with a bin-mapping strategy. Physically, 308 scaffolds with 193.2 Mbp total DNA sequences were anchored onto this consensus map that covered 52.6% of the 367 Mbp cucumber genome. Conclusions Cucumber contains relatively few NB-LRR RGHs that are clustered and unevenly distributed in the genome. All RGHs seem to be transcribed and shared significant sequence homology and synteny with the melon

  5. Sparkle/PM3 Parameters for the Modeling of Neodymium(III), Promethium(III), and Samarium(III) Complexes.

    PubMed

    Freire, Ricardo O; da Costa, Nivan B; Rocha, Gerd B; Simas, Alfredo M

    2007-07-01

    The Sparkle/PM3 model is extended to neodymium(III), promethium(III), and samarium(III) complexes. The unsigned mean error, for all Sparkle/PM3 interatomic distances between the trivalent lanthanide ion and the ligand atoms of the first sphere of coordination, is 0.074 Å for Nd(III); 0.057 Å for Pm(III); and 0.075 Å for Sm(III). These figures are similar to the Sparkle/AM1 ones of 0.076 Å, 0.059 Å, and 0.075 Å, respectively, indicating they are all comparable models. Moreover, their accuracy is similar to what can be obtained by present-day ab initio effective potential calculations on such lanthanide complexes. Hence, the choice of which model to utilize will depend on the assessment of the effect of either AM1 or PM3 on the quantum chemical description of the organic ligands. Finally, we present a preliminary attempt to verify the geometry prediction consistency of Sparkle/PM3. Since lanthanide complexes are usually flexible, we randomly generated 200 different input geometries for the samarium complex QIPQOV which were then fully optimized by Sparkle/PM3. A trend appeared in that, on average, the lower the total energy of the local minima found, the lower the unsigned mean errors, and the higher the accuracy of the model. These preliminary results do indicate that attempting to find, with Sparkle/PM3, a global minimum for the geometry of a given complex, with the understanding that it will tend to be closer to the experimental geometry, appears to be warranted. Therefore, the sparkle model is seemingly a trustworthy semiempirical quantum chemical model for the prediction of lanthanide complexes geometries. PMID:26633229

  6. PM3 semi-empirical IR spectra simulations for metal complexes of schiff bases of sulfa drugs

    NASA Astrophysics Data System (ADS)

    Topacli, C.; Topacli, A.

    2003-06-01

    The molecular structures and infrared spectra of Co, Ni, Cu and Zn complexes of two schiff base ligands, viz N-( o-vanillinidene)sulfanilamide ( oVSaH) and N-( o-vanillinidene)sulfamerazine ( oVSmrzH) are studied in detail by PM3 method. It has been shown that the proposed structures for the compounds derived from microanalytical, magnetic and various spectral data were consistent with the IR spectra simulated by PM3 method. Coordination effects on ν(CN) and ν(C-O) modes in the schiff base ligands are in close agreement with the observed results.

  7. Applicability of PM3 to transphosphorylation reaction path: Toward designing a minimal ribozyme

    NASA Technical Reports Server (NTRS)

    Manchester, John I.; Shibata, Masayuki; Setlik, Robert F.; Ornstein, Rick L.; Rein, Robert

    1993-01-01

    A growing body of evidence shows that RNA can catalyze many of the reactions necessary both for replication of genetic material and the possible transition into the modern protein-based world. However, contemporary ribozymes are too large to have self-assembled from a prebiotic oligonucleotide pool. Still, it is likely that the major features of the earliest ribozymes have been preserved as molecular fossils in the catalytic RNA of today. Therefore, the search for a minimal ribozyme has been aimed at finding the necessary structural features of a modern ribozyme (Beaudry and Joyce, 1990). Both a three-dimensional model and quantum chemical calculations are required to quantitatively determine the effects of structural features of the ribozyme on the reaction it catalyzes. Using this model, quantum chemical calculations must be performed to determine quantitatively the effects of structural features on catalysis. Previous studies of the reaction path have been conducted at the ab initio level, but these methods are limited to small models due to enormous computational requirements. Semiempirical methods have been applied to large systems in the past; however, the accuracy of these methods depends largely on a simple model of the ribozyme-catalyzed reaction, or hydrolysis of phosphoric acid. We find that the results are qualitatively similar to ab initio results using large basis sets. Therefore, PM3 is suitable for studying the reaction path of the ribozyme-catalyzed reaction.

  8. Hydrogen peroxide, nitric oxide and UV RESISTANCE LOCUS8 interact to mediate UV-B-induced anthocyanin biosynthesis in radish sprouts

    PubMed Central

    Wu, Qi; Su, Nana; Zhang, Xiaoyan; Liu, Yuanyuan; Cui, Jin; Liang, Yongchao

    2016-01-01

    The cross talk among hydrogen peroxide (H2O2), nitric oxide (NO) and UV RESISTANCE LOCUS8 (UVR8) in UV-B-induced anthocyanin accumulation in the hypocotyls of radish sprouts was investigated. The results showed that UV-B irradiation significantly increased the anthocyanin accumulation and the expression of UVR8, and a similar trend appeared in radish sprouts subjected to cadmium, chilling and salt stresses regardless of light source. However, these responses disappeared under dark exposure. These results suggest that abiotic stress-induced anthocyanin accumulation and UVR8 expression were light-dependent. Moreover, abiotic stresses all enhanced the production of H2O2 and exogenous H2O2 addition significantly increased the anthocyanin concentration and UVR8 transcription, while these increases were severely inhibited by addition of dimethylthiourea (DMTU, a chemical trap for H2O2). It seems to suggest that H2O2 played an important role in the anthocyanin biosynthesis. Furthermore, addition of 0.5 mM sodium nitroprusside (SNP, a NO-releasing compound) substantially induced the anthocyanin accumulation, and H2O2-induced anthocyanin accumulation and UVR8 expression were significantly suppressed by co-treatment with 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO, a NO scavenger), which was parallel with the expression of anthocyanin biosynthesis-related transcription factors and structural genes. All these results demonstrate that both H2O2 and NO are involved in UV-B-induced anthocyanin accumulation, and there is a crosstalk between them as well as a classical UVR8 pathway. PMID:27404993

  9. The cyclophilin CYP20-2 modulates the conformation of BRASSINAZOLE-RESISTANT1, which binds the promoter of FLOWERING LOCUS D to regulate flowering in Arabidopsis.

    PubMed

    Zhang, Yuanyuan; Li, Beibei; Xu, Yunyuan; Li, Heng; Li, Shanshan; Zhang, Dajian; Mao, Zhiwei; Guo, Siyi; Yang, Chunhong; Weng, Yuxiang; Chong, Kang

    2013-07-01

    Brassinosteroids (BRs) regulate many physiological processes during plant development, including flowering. However, little is known about the components of BR signaling that mediate flowering. Here, we report that BRASSINAZOLE-RESISTANT1 (BZR1), the conformation of which is altered by a cyclophilin (CYP20-2), binds cis-elements in the FLOWERING LOCUS D (FLD) promoter to regulate flowering. Both bzr1-1D and fld-4 showed delayed flowering. Electrophoretic mobility shift assay and chromatin immunoprecipitation revealed that BZR1 bound to a putative BR response cis-element and suppressed the expression of FLD. Overexpression of FLD partially rescued the late flowering of pBZR1:mBZR1(Pro234-Leu)-CFP (mx3). Yeast two-hybrid and pull-down assays demonstrated that BZR1 interacts with CYP20-2. Arabidopsis thaliana CYP20-2 had greater peptidyl-prolyl cis-trans isomerase activity than did wheat (Triticum aestivum) CYP20-2. Fourier transform infrared spectroscopy revealed conformation changes in BZR1, dependent on interaction with CYP20-2. Due to differences in activity and substrate preference between CYP20-2 proteins from wheat and Arabidopsis, At-CYP20-2-overexpressing lines showed earlier flowering, whereas Ta CYP20-2 lines flowered later. Immunoblot and chromatin immunoprecipitation assays showed that histone H3 trimethyl Lys4 and H3 acetylation levels were negatively correlated with the transcription of FLD (a putative histone demethylase) in various lines. Therefore, a conformational change of BZR1 mediated by CYP20-2 causes altered flowering through modulation of FLD expression. PMID:23897924

  10. The Bcg/Ity/Lsh locus: genetic transfer of resistance to infections in C57BL/6J mice transgenic for the Nramp1 Gly169 allele.

    PubMed Central

    Govoni, G; Vidal, S; Gauthier, S; Skamene, E; Malo, D; Gros, P

    1996-01-01

    The murine Bcg/Ity/Lsh locus determines the susceptibilities of inbred strains to infection with unrelated intracellular parasites, such as Mycobacterium bovis, Salmonella typhimurium, and Leishmania donovani. A candidate for Bcg/Ity/Lsh, designated Nramp1, has been recently identified and shown to encode a novel integral membrane protein that is expressed exclusively in professional phagocytes but whose function remains unknown. In inbred strains, the susceptibility to infection is associated with a single glycine-to-aspartic acid substitution at position 169 (G169D) in the predicted TM4 of the protein. To confirm the candidacy of Nramp1 as Bcg/Ity/Lsh and to determine the importance of the G169D mutation on Nramp1 function, we constructed transgenic mice in which the G169 allele of Nramp1 was transferred onto the background of a homozygous D169 allele. These transgenic mice were analyzed for their sensitivity to infections under the control of Bcg/Ity/Lsh. The transgene constructed for these studies contained the entire Nramp1G169 gene together with approximately 5 kb of sequences upstream of the transcription initiation site of this gene. We observed that these sequences were sufficient to direct Nramp1G169 expression in transgenic macrophages, resulting in the appearance of a mature protein of 90 to 100 kDa over a background of Nramp1G169 characterized by the complete absence of the mature Nramp1 polypeptide. The appearance of the Nramp1G169-encoded protein in transgenic macrophages was concomitant with the emergence of resistance to infection by M. bovis BCG, as measured by the extent of bacteria] replication in the spleen, and by S. typhimurium, as measured by survival after an intravenous challenge. The gain of function detected in transgenic Nramp1G169 animals establishes unambiguously that Nramp1 and Bcg/Ity/Lsh are allelic. PMID:8757814

  11. Hydrogen peroxide, nitric oxide and UV RESISTANCE LOCUS8 interact to mediate UV-B-induced anthocyanin biosynthesis in radish sprouts.

    PubMed

    Wu, Qi; Su, Nana; Zhang, Xiaoyan; Liu, Yuanyuan; Cui, Jin; Liang, Yongchao

    2016-01-01

    The cross talk among hydrogen peroxide (H2O2), nitric oxide (NO) and UV RESISTANCE LOCUS8 (UVR8) in UV-B-induced anthocyanin accumulation in the hypocotyls of radish sprouts was investigated. The results showed that UV-B irradiation significantly increased the anthocyanin accumulation and the expression of UVR8, and a similar trend appeared in radish sprouts subjected to cadmium, chilling and salt stresses regardless of light source. However, these responses disappeared under dark exposure. These results suggest that abiotic stress-induced anthocyanin accumulation and UVR8 expression were light-dependent. Moreover, abiotic stresses all enhanced the production of H2O2 and exogenous H2O2 addition significantly increased the anthocyanin concentration and UVR8 transcription, while these increases were severely inhibited by addition of dimethylthiourea (DMTU, a chemical trap for H2O2). It seems to suggest that H2O2 played an important role in the anthocyanin biosynthesis. Furthermore, addition of 0.5 mM sodium nitroprusside (SNP, a NO-releasing compound) substantially induced the anthocyanin accumulation, and H2O2-induced anthocyanin accumulation and UVR8 expression were significantly suppressed by co-treatment with 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO, a NO scavenger), which was parallel with the expression of anthocyanin biosynthesis-related transcription factors and structural genes. All these results demonstrate that both H2O2 and NO are involved in UV-B-induced anthocyanin accumulation, and there is a crosstalk between them as well as a classical UVR8 pathway. PMID:27404993

  12. Identification of a Rice stripe necrosis virus resistance locus and yield component QTLs using Oryza sativa × O. glaberrima introgression lines

    PubMed Central

    2010-01-01

    Background Developing new population types based on interspecific introgressions has been suggested by several authors to facilitate the discovery of novel allelic sources for traits of agronomic importance. Chromosome segment substitution lines from interspecific crosses represent a powerful and useful genetic resource for QTL detection and breeding programs. Results We built a set of 64 chromosome segment substitution lines carrying contiguous chromosomal segments of African rice Oryza glaberrima MG12 (acc. IRGC103544) in the genetic background of Oryza sativa ssp. tropical japonica (cv. Caiapó). Well-distributed simple-sequence repeats markers were used to characterize the introgression events. Average size of the substituted chromosomal segments in the substitution lines was about 10 cM and covered the whole donor genome, except for small regions on chromosome 2 and 4. Proportions of recurrent and donor genome in the substitution lines were 87.59% and 7.64%, respectively. The remaining 4.78% corresponded to heterozygotes and missing data. Strong segregation distortion was found on chromosomes 3 and 6, indicating the presence of interspecific sterility genes. To illustrate the advantages and the power of quantitative trait loci (QTL) detection using substitution lines, a QTL detection was performed for scored traits. Transgressive segregation was observed for several traits measured in the population. Fourteen QTLs for plant height, tiller number per plant, panicle length, sterility percentage, 1000-grain weight and grain yield were located on chromosomes 1, 3, 4, 6 and 9. Furthermore, a highly significant QTL controlling resistance to the Rice stripe necrosis virus was located between SSR markers RM202-RM26406 (44.5-44.8 cM) on chromosome 11. Conclusions Development and phenotyping of CSSL libraries with entire genome coverage represents a useful strategy for QTL discovery. Mapping of the RSNV locus represents the first identification of a genetic factor

  13. Prediction for thermodynamic function of dioxins for gas phase using semi-empirical molecular orbital method with PM3 Hamiltonian.

    PubMed

    Saito, N; Fuwa, A

    2000-01-01

    In this investigation, respective thermodynamic parameters of heats of formation, standard entropy and specific heat capacity at constant pressure for PCDDs, PCDFs, Co-PCB and PCBs as well as polychlorinated-benzenes and polychlorinated-phenols have been evaluated by quantum chemical calculation using a semi-empirical molecular orbital method with the PM3 Hamiltonian and statistical thermodynamic correlation. PMID:10665426

  14. A high-resolution map of the Grp1 locus on chromosome V of potato harbouring broad-spectrum resistance to the cyst nematode species Globodera pallida and Globodera rostochiensis.

    PubMed

    Finkers-Tomczak, Anna; Danan, Sarah; van Dijk, Thijs; Beyene, Amelework; Bouwman, Liesbeth; Overmars, Hein; van Eck, Herman; Goverse, Aska; Bakker, Jaap; Bakker, Erin

    2009-06-01

    The Grp1 locus confers broad-spectrum resistance to the potato cyst nematode species Globodera pallida and Globodera rostochiensis and is located in the GP21-GP179 interval on the short arm of chromosome V of potato. A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes. The flanking markers GP21 and GP179 have been used to screen the 1,536 genotypes for recombination events. Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432. Detailed analysis of the 44 recombinant genotypes showed that G. pallida and G. rostochiensis resistance could not be separated and map to the same location between marker SPUD838 and TG432. It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class. PMID:19363662

  15. Molecular cloning and functional analysis of a UV-B photoreceptor gene, MdUVR8 (UV Resistance Locus 8), from apple.

    PubMed

    Zhao, Cheng; Mao, Ke; You, Chun-Xiang; Zhao, Xian-Yan; Wang, Shu-Hui; Li, Yuan-Yuan; Hao, Yu-Jin

    2016-06-01

    UVR8 (UV Resistance Locus 8) is an ultraviolet-B (UV-B; 280-315nm) light receptor that is involved in regulating many aspects of plant growth and development. UV-B irradiation can increase the development of flower and fruit coloration in many fruit trees, such as grape, pear and apple. Previous investigations of the structure and functions of UVR8 in plants have largely focused on Arabidopsis. Here, we isolated the UVR8 gene from apple (Malus domestica) and analyzed its function in transgenic Arabidopsis. Genomic and protein sequence analysis showed that MdUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis, including the conserved seven-bladed β-propeller, the C27 region, the 3 "GWRHT" motifs and crucial amino-acid residues (14 Trps, 2 Args). A point mutation prediction and three-dimensional structural analysis of MdUVR8 indicated that it has a similar structure to AtUVR8 and that the crucial residues are also important in MdUVR8. In terms of transcript levels, MdUVR8 expression was up-regulated by UV-B light, which suggests that its expression follows a 24-h circadian rhythm. Using heterologous expression of MdUVR8 in both uvr8-1 mutant and wild-type (WT) Arabidopsis, we found that MdUVR8 regulates hypocotyl elongation and gene expression under UV-B light. These data provide functional evidence for a role of MdUVR8 in controlling photomorphogenesis under UV-B light and indicate that the function of UVR8 is conserved between Arabidopsis and apple. Furthermore, we examined the interaction between MdUVR8 and MdCOP1 (constitutive photomorphogenic1) using a yeast two-hybrid assay and a co-immunoprecipitation assay. This interaction provides a direction for investigating the regulatory mechanisms of the UV-B-light pathway in apple. PMID:27095405

  16. ICESluvan, a 94-Kilobase Mosaic Integrative Conjugative Element Conferring Interspecies Transfer of VanB-Type Glycopeptide Resistance, a Novel Bacitracin Resistance Locus, and a Toxin-Antitoxin Stabilization System

    PubMed Central

    Bjørkeng, Eva K.; Hjerde, Erik; Pedersen, Torunn; Sundsfjord, Arnfinn

    2013-01-01

    A 94-kb integrative conjugative element (ICESluvan) transferable to Enterococcus faecium and Enterococcus faecalis from an animal isolate of Streptococcus lutetiensis consists of a mosaic of genetic fragments from different Gram-positive bacteria. A variant of ICESluvan was confirmed in S. lutetiensis from a patient. A complete Tn5382/Tn1549 with a vanB2 operon is integrated into a streptococcal ICESde3396-like region harboring a putative bacteriophage exclusion system, a putative agglutinin receptor precursor, and key components of a type IV secretion system. Moreover, ICESluvan encodes a putative MobC family mobilization protein and a relaxase and, thus, in total has all genetic components essential for conjugative transfer. A 9-kb element within Tn5382/Tn1549 encodes, among others, putative proteins similar to the TnpX site-specific recombinase in Faecalibacterium and VanZ in Paenibacillus, which may contribute to the detected low-level teicoplanin resistance. Furthermore, ICESluvan encodes a novel bacitracin resistance locus that is associated with reduced susceptibility to bacitracin when transferred to E. faecium. The expression of a streptococcal pezAT toxin-antitoxin-encoding operon of ICESluvan in S. lutetiensis, E. faecium, and E. faecalis was confirmed by reverse transcription (RT)-PCR, indicating an active toxin-antitoxin system which may contribute to stabilizing ICESluvan within new hosts. Junction PCR and DNA sequencing confirmed that ICESluvan excised to form a circular intermediate in S. lutetiensis, E. faecalis, and E. faecium. Transfer between E. faecalis cells was observed in the presence of helper plasmid pIP964. Sequence analysis of the original S. lutetiensis donor and enterococcal transconjugants showed that ICESluvan integrates in a site-specific manner into the C-terminal end of the chromosomal tRNA methyltransferase gene rumA. PMID:24078615

  17. The wheat Phs-A1 pre-harvest sprouting resistance locus delays the rate of seed dormancy loss and maps 0.3 cM distal to the PM19 genes in UK germplasm.

    PubMed

    Shorinola, Oluwaseyi; Bird, Nicholas; Simmonds, James; Berry, Simon; Henriksson, Tina; Jack, Peter; Werner, Peter; Gerjets, Tanja; Scholefield, Duncan; Balcárková, Barbara; Valárik, Miroslav; Holdsworth, M J; Flintham, John; Uauy, Cristobal

    2016-07-01

    The precocious germination of cereal grains before harvest, also known as pre-harvest sprouting, is an important source of yield and quality loss in cereal production. Pre-harvest sprouting is a complex grain defect and is becoming an increasing challenge due to changing climate patterns. Resistance to sprouting is multi-genic, although a significant proportion of the sprouting variation in modern wheat cultivars is controlled by a few major quantitative trait loci, including Phs-A1 in chromosome arm 4AL. Despite its importance, little is known about the physiological basis and the gene(s) underlying this important locus. In this study, we characterized Phs-A1 and show that it confers resistance to sprouting damage by affecting the rate of dormancy loss during dry seed after-ripening. We show Phs-A1 to be effective even when seeds develop at low temperature (13 °C). Comparative analysis of syntenic Phs-A1 intervals in wheat and Brachypodium uncovered ten orthologous genes, including the Plasma Membrane 19 genes (PM19-A1 and PM19-A2) previously proposed as the main candidates for this locus. However, high-resolution fine-mapping in two bi-parental UK mapping populations delimited Phs-A1 to an interval 0.3 cM distal to the PM19 genes. This study suggests the possibility that more than one causal gene underlies this major pre-harvest sprouting locus. The information and resources reported in this study will help test this hypothesis across a wider set of germplasm and will be of importance for breeding more sprouting resilient wheat varieties. PMID:27217549

  18. Genome-Wide Scan and Test of Candidate Genes in the Snail Biomphalaria glabrata Reveal New Locus Influencing Resistance to Schistosoma mansoni

    PubMed Central

    Tennessen, Jacob A.; Bonner, Kaitlin M.; Bollmann, Stephanie R.; Johnstun, Joel A.; Yeh, Jan-Ying; Marine, Melanie; Tavalire, Hannah F.; Bayne, Christopher J.; Blouin, Michael S.

    2015-01-01

    Background New strategies to combat the global scourge of schistosomiasis may be revealed by increased understanding of the mechanisms by which the obligate snail host can resist the schistosome parasite. However, few molecular markers linked to resistance have been identified and characterized in snails. Methodology/Principal Findings Here we test six independent genetic loci for their influence on resistance to Schistosoma mansoni strain PR1 in the 13-16-R1 strain of the snail Biomphalaria glabrata. We first identify a genomic region, RADres, showing the highest differentiation between susceptible and resistant inbred lines among 1611 informative restriction-site associated DNA (RAD) markers, and show that it significantly influences resistance in an independent set of 439 outbred snails. The additive effect of each RADres resistance allele is 2-fold, similar to that of the previously identified resistance gene sod1. The data fit a model in which both loci contribute independently and additively to resistance, such that the odds of infection in homozygotes for the resistance alleles at both loci (13% infected) is 16-fold lower than the odds of infection in snails without any resistance alleles (70% infected). Genome-wide linkage disequilibrium is high, with both sod1 and RADres residing on haplotype blocks >2Mb, and with other markers in each block also showing significant effects on resistance; thus the causal genes within these blocks remain to be demonstrated. Other candidate loci had no effect on resistance, including the Guadeloupe Resistance Complex and three genes (aif, infPhox, and prx1) with immunological roles and expression patterns tied to resistance, which must therefore be trans-regulated. Conclusions/Significance The loci RADres and sod1 both have strong effects on resistance to S. mansoni. Future approaches to control schistosomiasis may benefit from further efforts to characterize and harness this natural genetic variation. PMID:26372103

  19. Structural, Electronic and Qsar Properties of the Cyfluthrin Molecule:. a Theoretical AM1 and PM3 Treatment

    NASA Astrophysics Data System (ADS)

    Çalişir, Emine Deniz; Erkoç, Şakir

    Cyfluthrin is a synthetic cyano-containing pyrethroid insecticide that has both contact and stomach poison action. It is a nonsystemic chemical used to control cutworms, ants, silverfish, cockroaches, mosquitoes, tobacco budworm and many others. Its primary agricultural uses have been for control of chewing and sucking insects on crops such as cotton, turf, ornamentals, hops, cereal, corn, deciduous fruit, peanuts, potatoes, and other vegetables. Cyfluthrin is also used in public health situations and for structural pest control. The structural, vibrational, electronic and QSAR properties of the cyfluthrin molecule in gas phase have been investigated theoretically by performing molecular mechanics method by using MM+ force field, and semi-empirical molecular orbital AM1 and PM3 calculations. The geometry of the molecule has been optimized, infrared spectrum (vibrational modes and intensities) and the electronic properties of the molecule have been calculated in its ground state. According to PM3 calculation, heat of formation of cyfluthrin molecule is about -48.58 kcal/mol (exothermic), which shows that this molecule thermodynamically be stable. The HOMO energy level for this molecule is found to be -9.701 eV and the LUMO energy level is -0.660 eV giving rise to a gap of 9.041 eV, which also indicates that cyfluthrin is thermodynamically stable.

  20. NMR structure of rALF-Pm3, an anti-lipopolysaccharide factor from shrimp: model of the possible lipid A-binding site.

    PubMed

    Yang, Yinshan; Boze, Hélène; Chemardin, Patrick; Padilla, André; Moulin, Guy; Tassanakajon, Anchalee; Pugnière, Martine; Roquet, Françoise; Destoumieux-Garzón, Delphine; Gueguen, Yannick; Bachère, Evelyne; Aumelas, André

    2009-03-01

    The anti-lipopolysaccharide factor ALF-Pm3 is a 98-residue protein identified in hemocytes from the black tiger shrimp Penaeus monodon. It was expressed in Pichia pastoris from the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter as a folded and (15)N uniformly labeled rALF-Pm3 protein. Its 3D structure was established by NMR and consists of three alpha-helices packed against a four-stranded beta-sheet. The C(34)-C(55) disulfide bond was shown to be essential for the structure stability. By using surface plasmon resonance, we demonstrated that rALF-Pm3 binds to LPS, lipid A and to OM-174, a soluble analogue of lipid A. Biophysical studies of rALF-Pm3/LPS and rALF-Pm3/OM-174 complexes indicated rather high molecular sized aggregates, which prevented us to experimentally determine by NMR the binding mode of these lipids to rALF-Pm3. However, on the basis of striking structural similarities to the FhuA/LPS complex, we designed an original model of the possible lipid A-binding site of ALF-Pm3. Such a binding site, located on the ALF-Pm3 beta-sheet and involving seven charged residues, is well conserved in ALF-L from Limulus polyphemus and in ALF-T from Tachypleus tridentatus. In addition, our model is in agreement with experiments showing that beta-hairpin synthetic peptides corresponding to ALF-L beta-sheet bind to LPS. Delineating lipid A-binding site of ALFs will help go further in the de novo design of new antibacterial or LPS-neutralizing drugs. PMID:19107926

  1. Mapping of a stem rust resistance locus effective against Ug99 on wheat chromosome 7AL using a RAD-Seq approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat stem rust is responsible for major production losses around the world. The development of resistant cultivars is an effective way to manage the disease, but outbreaks can occur when new pathogen races overcome the existing resistances. Ug99 (race TTKSK), and related newly-emerged, highly virul...

  2. CAPS markers in an eIF4E gene are linked to Zucchini yellow mosaic virus resistant locus in watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zucchini yellow mosaic virus (ZYMV) is an economically important virus infecting cucurbits worldwide. Genetic sources of resistance to ZYMV have been identified in wild watermelon germplasm where a single recessive gene (zym) confers ZYMV resistance. Marker-assisted selection (MAS) would greatly fa...

  3. Bulk Segregate Analysis using the GoldenGate Assay to Locate the Rpp3 Locus that Confers Resistance to Phakopsora pachyrhizi (Soybean Rust) in Soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few resistance genes to soybean rust (SBR), caused by Phakopsora pachyrhizi Syd., have been genetically mapped and linked to molecular markers that can be used for marker assisted selection. New technologies are available for SNP genotyping that can be used to rapidly map single gene resistance to ...

  4. Relationship between Yield Components and Partial Resistance to Lecanicillium fungicola in the Button Mushroom, Agaricus bisporus, Assessed by Quantitative Trait Locus Mapping

    PubMed Central

    Rodier, Anne; Savoie, Jean-Michel

    2012-01-01

    Dry bubble, caused by Lecanicillium fungicola, is one of the most detrimental diseases affecting button mushroom cultivation. In a previous study, we demonstrated that breeding for resistance to this pathogen is quite challenging due to its quantitative inheritance. A second-generation hybrid progeny derived from an intervarietal cross between a wild strain and a commercial cultivar was characterized for L. fungicola resistance under artificial inoculation in three independent experiments. Analysis of quantitative trait loci (QTL) was used to determine the locations, numbers, and effects of genomic regions associated with dry-bubble resistance. Four traits related to resistance were analyzed. Two to four QTL were detected per trait, depending on the experiment. Two genomic regions, on linkage group X (LGX) and LGVIII, were consistently detected in the three experiments. The genomic region on LGX was detected for three of the four variables studied. The total phenotypic variance accounted for by all QTL ranged from 19.3% to 42.1% over all traits in all experiments. For most of the QTL, the favorable allele for resistance came from the wild parent, but for some QTL, the allele that contributed to a higher level of resistance was carried by the cultivar. Comparative mapping with QTL for yield-related traits revealed five colocations between resistance and yield component loci, suggesting that the resistance results from both genetic factors and fitness expression. The consequences for mushroom breeding programs are discussed. PMID:22247161

  5. The Nematode Resistance Allele at the rhg1 Locus Alters the Proteome and Primary Metabolism of Soybean Roots1[C][W][OA

    PubMed Central

    Afzal, Ahmed J.; Natarajan, Aparna; Saini, Navinder; Iqbal, M. Javed; Geisler, Matt; El Shemy, Hany A.; Mungur, Rajsree; Willmitzer, Lothar; Lightfoot, David A.

    2009-01-01

    Heterodera glycines, the soybean cyst nematode (SCN), causes the most damaging chronic disease of soybean (Glycine max). Host resistance requires the resistance allele at rhg1. Resistance destroys the giant cells created in the plant's roots by the nematodes about 24 to 48 h after commencement of feeding. In addition, 4 to 8 d later, a systemic acquired resistance develops that discourages later infestations. The molecular mechanisms that control the rhg1-mediated resistance response appear to be multigenic and complex, as judged by transcript abundance changes, even in near isogenic lines (NILs). This study aimed to focus on key posttranscriptional changes by identifying proteins and metabolites that were increased in abundance in both resistant and susceptible NILs. Comparisons were made among NILs 10 d after SCN infestation and without SCN infestation. Two-dimensional gel electrophoresis resolved more than 1,000 protein spots on each gel. Only 30 protein spots with a significant (P < 0.05) difference in abundance of 1.5-fold or more were found among the four treatments. The proteins in these spots were picked, trypsin digested, and analyzed using quadrupole time-of-flight tandem mass spectrometry. Protein identifications could be made for 24 of the 30 spots. Four spots contained two proteins, so that 28 distinct proteins were identified. The proteins were grouped into six functional categories. Metabolite analysis by gas chromatography-mass spectrometry identified 131 metabolites, among which 58 were altered by one or more treatment; 28 were involved in primary metabolism. Taken together, the data showed that 17 pathways were altered by the rhg1 alleles. Pathways altered were associated with systemic acquired resistance-like responses, including xenobiotic, phytoalexin, ascorbate, and inositol metabolism, as well as primary metabolisms like amino acid synthesis and glycolysis. The pathways impacted by the rhg1 allelic state and SCN infestation agreed with

  6. Identification of a CAPS marker in an eIF4E gene Linked to Zucchini yellow mosaic virus resistant locus in watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genes that encode eukaryotic initiation factors (eIF) 4E and iso(4E) have been associated with the recessively inherited resistance to potyviruses in a number of plant species. Using previously developed degenerate primers, partial eIF4E and eIF(iso)4E gene sequence regions were obtained through po...

  7. Quantitative trait locus mapping for Verticillium wilt resistance in a backcross inbred line population of cotton (Gossypium hirsutum × Gossypium barbadense) based on RGA-AFLP analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verticillium wilt (VW), caused by Verticillium dahliae, is one of the most important diseases in cotton. Development and growing of VW resistant cultivars is the most effective and economic strategy in controlling the disease. However, little is currently known on the genetic basis of VW resistanc...

  8. Identification and Genomic Location of a Reniform Nematode (Rotylenchulus reniformis) Resistance locus (Ren_ari) Introgressed from Gossypium aridum into Upland Cotton (G. hirsutum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this association mapping study, a tri-species hybrid, [G. arboreum × (G. hirsutum × G aridum)], was crossed with MD51ne (G. hirsutum) and progeny from the cross were used to identify and map SSR markers associated with reniform nematode (Rotylenchulus reniformis) resistance. Seventy six progeny ...

  9. Tan spot susceptibility governed by the Tsn1 locus and race-nonspecific resistance quantitative trait loci in a population derived from the wheat lines Salamouni and Katepwa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat-tan spot interactions are known to have an inverse gene-for-gene relationship where pathogen-produced necrotrophic effectors are recognized by host sensitivity genes to cause susceptibility. However, broad-spectrum non race-specific resistance quantitative trait loci (QTL) that do not conform...

  10. Barley Germplasm STARS-9577B lacks a Russian Wheat Aphid Resistance Allele at a Quantitative Trait Locus Present in STARS-9301B

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Russian wheat aphid (RWA, Diuraphis noxia Kurdjumov) infestations of barley (Hordeum vulgare L.) in the western U.S.A. have reduced yield and quality of barley since its introduction in 1986. Resistant germplasm lines have been released and used for cultivar development, including ‘STARS-9577B’, a s...

  11. Evolution of New Disease Specificity at a Single Resistance Locus in a Crop-Weed Complex: Reconstitution of the Lr21 Gene in Wheat.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf-rust resistance gene Lr21, present in modern varieties of hexaploid wheat, originated in goatgrass Aegilops tauschii Coss., the D genome donor of wheat. The goatgrass donor was collected in Iran where it grows as a weed in wheat fields as part of the native agricultural ecosystem. In order to ...

  12. Identification of a candidate gene for the wheat endopeptidase Ep-D1 locus and two other STS markers linked to the eyespot resistance gene Pch1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat is prone to strawbreaker foot rot (eye- spot), a fungal disease caused by Oculimacula yallundae and O. acuformis. The most effective source of genetic resistance is Pch1, a gene derived from Aegilops ventri- cosa. The endopeptidase isozyme marker allele Ep-D1b, linked to Pch1, has been shown t...

  13. Cloning and function validation of a nb-arc-lrr-type candidate gene for the greenbug aphid resistance locus, Gb3, in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The greenbug, Schizaphis graminum, is one of the most important aphid pests of small grain crops in many parts of the world. A single dominant gene, Gb3 originated from Aegilops tauschii has shown consistent and durable resistance against prevailing greenbug biotypes in wheat fields. A fine genetic ...

  14. Fate of Mutation Rate Depends on agr Locus Expression during Oxacillin-Mediated Heterogeneous-Homogeneous Selection in Methicillin-Resistant Staphylococcus aureus Clinical Strains ▿ †

    PubMed Central

    Plata, Konrad B.; Rosato, Roberto R.; Rosato, Adriana E.

    2011-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) strains are characterized by a heterogeneous expression of resistance. We have previously shown in clinical oxacillin-susceptible, mecA-positive MRSA strains that selection from a very heterogeneous (HeR) to highly homogeneous (HoR) resistant phenotype was mediated by acquisition of mutations through an oxacillin-induced SOS response. In the present study, we used a spotted DNA microarray to evaluate differential gene expression during HeR-HoR selection and found increased expression of the agr two-component regulatory system. We hypothesized that increased expression of agr represents a mechanistically relevant component of this process. We demonstrated that inactivation of agr during the HeR-HoR selection process results in a significant increase in mutation rate; these effects were reversed by complementing the agr mutant. Furthermore, we found that extemporal ectopic expression of agr and, more specifically, RNAII in agr-null mutant HeR cells suppressed mutation frequency and the capacity of these cells to undergo the HeR-HoR selection. These findings sustain the concept that increased expression of agr during HeR-HoR selection plays a critical role in regulating the β-lactam-induced increased mutation rate in very heterogeneous MRSA strains. Moreover, they indicate that a temporally controlled increase in agr expression is required to tightly modulate SOS-mediated mutation rates, which then allows for full expression of oxacillin homogeneous resistance in very heterogeneous clinical MRSA strains. PMID:21537016

  15. GpaXI ( tar ) ( l ) originating from Solanum tarijense is a major resistance locus to Globodera pallida and is localised on chromosome 11 of potato.

    PubMed

    Adillah Tan, M Y; Park, Tae-Ho; Alles, René; Hutten, Ronald C B; Visser, R G F; van Eck, Herman J

    2009-11-01

    Resistance to Globodera pallida Rookmaker (Pa3), originating from wild species Solanum tarijense was identified by QTL analysis and can be largely ascribed to one major QTL. GpaXI ( tar ) ( l ) explained 81.3% of the phenotypic variance in the disease test. GpaXI ( tar ) ( l ) is mapped to the long arm of chromosome 11. Another minor QTL explained 5.3% of the phenotypic variance and mapped to the long arm of chromosome 9. Clones containing both QTL showed no lower cyst counts than clones with only GpaXI ( tar ) ( l ) . After Mendelising the phenotypic data, GpaXI ( tar ) ( l ) could be more precisely mapped near markers GP163 and FEN427, thus anchoring GpaXI ( tar ) ( l ) to a region with a known R-gene cluster containing virus and nematode resistance genes. PMID:19816672

  16. Genetic Analysis Using an Isogenic Mating Pair of Aspergillus fumigatus Identifies Azole Resistance Genes and Lack of MAT Locus's Role in Virulence.

    PubMed

    Losada, Liliana; Sugui, Janyce A; Eckhaus, Michael A; Chang, Yun C; Mounaud, Stephanie; Figat, Abigail; Joardar, Vinita; Pakala, Suman B; Pakala, Suchitra; Venepally, Pratap; Fedorova, Natalie; Nierman, William C; Kwon-Chung, Kyung J

    2015-04-01

    Invasive aspergillosis (IA) due to Aspergillus fumigatus is a major cause of mortality in immunocompromised patients. The discovery of highly fertile strains of A. fumigatus opened the possibility to merge classical and contemporary genetics to address key questions about this pathogen. The merger involves sexual recombination, selection of desired traits, and genomics to identify any associated loci. We constructed a highly fertile isogenic pair of A. fumigatus strains with opposite mating types and used them to investigate whether mating type is associated with virulence and to find the genetic loci involved in azole resistance. The pair was made isogenic by 9 successive backcross cycles of the foundational strain AFB62 (MAT1-1) with a highly fertile (MAT1-2) progeny. Genome sequencing showed that the F9 MAT1-2 progeny was essentially identical to the AFB62. The survival curves of animals infected with either strain in three different animal models showed no significant difference, suggesting that virulence in A. fumigatus was not associated with mating type. We then employed a relatively inexpensive, yet highly powerful strategy to identify genomic loci associated with azole resistance. We used traditional in vitro drug selection accompanied by classical sexual crosses of azole-sensitive with resistant isogenic strains. The offspring were plated under varying drug concentrations and pools of resulting colonies were analyzed by whole genome sequencing. We found that variants in 5 genes contributed to azole resistance, including mutations in erg11A (cyp51A), as well as multi-drug transporters, erg25, and in HMG-CoA reductase. The results demonstrated that with minimal investment into the sequencing of three pools from a cross of interest, the variation(s) that contribute any phenotype can be identified with nucleotide resolution. This approach can be applied to multiple areas of interest in A. fumigatus or other heterothallic pathogens, especially for virulence

  17. Cytological and molecular characterization of quantitative trait locus qRfg1, which confers resistance to gibberella stalk rot in maize.

    PubMed

    Ye, Jianrong; Guo, Yanling; Zhang, Dongfeng; Zhang, Nan; Wang, Chao; Xu, Mingliang

    2013-12-01

    Tremendous progress has been made recently in understanding plant response to Fusarium graminearum infection. Here, the cytological aspect and molecular mechanism of maize defense to F. graminearum infection were characterized using a pair of near-isogenic lines (NIL), the resistant and the susceptible NIL. F. graminearum primarily penetrated the maize root tip and no penetration structure was found. The fungal biomass within the root correlated well with root-disease severity. Following inoculation, R-NIL and S-NIL plants significantly differed in percentage of diseased primary roots. In R-NIL roots, a fraction of exodermal cells collapsed to form cavities, and hyphae were confined to the outer exodermal cells. However, most exodermal cells shrank and turned brown, and fungi colonized the entire S-NIL root. In the R-NIL roots, the exodermal cells exhibited plasmolysis and atropous hyphal growth whereas, in the exodermal cells of the S-NIL roots, severe cellular degradation and membrane-coated, lushly grown hyphae were found. Transcriptome sequencing revealed comprehensive transcription reprogramming, reinforcement of a complex defense network, to enhance the systemic and basal resistance. This study reports a detailed microscopic analysis of F. graminearum infection on maize root, and provides insights into the molecular mechanisms underlying maize resistance to the pathogen. PMID:23902264

  18. Putrescine production via the ornithine decarboxylation pathway improves the acid stress survival of Lactobacillus brevis and is part of a horizontally transferred acid resistance locus.

    PubMed

    Romano, Andrea; Ladero, Victor; Alvarez, Miguel A; Lucas, Patrick M

    2014-04-01

    Decarboxylation pathways are widespread among lactic acid bacteria; their physiological role is related to acid resistance through the regulation of the intracellular pH and to the production of metabolic energy via the generation of a proton motive force and its conversion into ATP. These pathways include, among others, biogenic amine (BA) production pathways. BA accumulation in foodstuffs is a health risk; thus, the study of the factors involved in their production is of major concern. The analysis of several lactic acid bacterial strains isolated from different environments, including fermented foods and beverages, revealed that the genes encoding these pathways are clustered on the chromosome, which suggests that these genes are part of a genetic hotspot related to acid stress resistance. Further attention was devoted to the ornithine decarboxylase pathway, which affords putrescine from ornithine. Studies were performed on three lactic acid bacteria belonging to different species. The ODC pathway was always shown to be involved in cytosolic pH alkalinisation and acid shock survival, which were observed to occur with a concomitant increase in putrescine production. PMID:24495587

  19. Sequence Analysis of a 282-Kilobase Region Surrounding the Citrus Tristeza Virus Resistance Gene (Ctv) Locus in Poncirus trifoliata L. Raf.1

    PubMed Central

    Yang, Zhong-Nan; Ye, Xin-Rong; Molina, Joe; Roose, Mikeal L.; Mirkov, T. Erik

    2003-01-01

    Citrus tristeza virus (CTV) is the major virus pathogen causing significant economic damage to citrus worldwide, and a single dominant gene, Ctv, provides broad spectrum resistance to CTV in Poncirus trifoliata L. Raf. Ctv was physically mapped to a 282-kb region using a P. trifoliata bacterial artificial chromosome library. This region was completely sequenced to about 8× coverage using a shotgun sequencing strategy and primer walking for gap closure. Sequence analysis predicts 22 putative genes, two mutator-like transposons and eight retrotransposons. This sequence analysis also revealed some interesting features of this region of the P. trifoliata genome: a disease resistance gene cluster with seven members and eight retrotransposons clustered in a 125-kb gene-poor region. Comparative sequence analysis suggests that six genes in the Ctv region have significant sequence similarity with their orthologs in bacterial artificial chromosome clones F7H2 and F21T11 from Arabidopsis chromosome I. However, the analysis of gene colinearity between P. trifoliata and Arabidopsis indicates that Arabidopsis genome sequence information may be of limited use for positional gene cloning in P. trifoliata and citrus. Analysis of candidate genes for Ctv is also discussed. PMID:12586873

  20. Sequence analysis of a 282-kilobase region surrounding the citrus Tristeza virus resistance gene (Ctv) locus in Poncirus trifoliata L. Raf.

    PubMed

    Yang, Zhong-Nan; Ye, Xin-Rong; Molina, Joe; Roose, Mikeal L; Mirkov, T Erik

    2003-02-01

    Citrus tristeza virus (CTV) is the major virus pathogen causing significant economic damage to citrus worldwide, and a single dominant gene, Ctv, provides broad spectrum resistance to CTV in Poncirus trifoliata L. Raf. Ctv was physically mapped to a 282-kb region using a P. trifoliata bacterial artificial chromosome library. This region was completely sequenced to about 8x coverage using a shotgun sequencing strategy and primer walking for gap closure. Sequence analysis predicts 22 putative genes, two mutator-like transposons and eight retrotransposons. This sequence analysis also revealed some interesting features of this region of the P. trifoliata genome: a disease resistance gene cluster with seven members and eight retrotransposons clustered in a 125-kb gene-poor region. Comparative sequence analysis suggests that six genes in the Ctv region have significant sequence similarity with their orthologs in bacterial artificial chromosome clones F7H2 and F21T11 from Arabidopsis chromosome I. However, the analysis of gene colinearity between P. trifoliata and Arabidopsis indicates that Arabidopsis genome sequence information may be of limited use for positional gene cloning in P. trifoliata and citrus. Analysis of candidate genes for Ctv is also discussed. PMID:12586873

  1. Emergence of a multidrug-resistant (ASSuTTm) strain of Salmonella enterica serovar Typhimurium DT120 in England in 2011 and the use of multiple-locus variable-number tandem-repeat analysis in supporting outbreak investigations.

    PubMed

    Paranthaman, Karthikeyan; Haroon, Sophie; Latif, Samia; Vinnyey, Natalie; de Souza, Valerie; Welfare, William; Tahir, Mamoona; Cooke, Edward; Stone, Kirsten; Lane, Chris; Peters, Tansy; Puleston, Richard

    2013-10-01

    In summer 2011, two outbreaks of a unique, multidrug-resistant strain of Salmonella enterica serovar Typhimurium phage type 120 (DT120) occurred mainly in the Midlands, England. The first outbreak occurred among guests attending a wedding in July 2011 ('Wedding outbreak'), followed by a more geographically dispersed outbreak in August and September 2011 ('Midlands outbreak'). Fifty-one cases were confirmed. Detailed epidemiological and environmental health investigations suggested that pork was the most likely source of both outbreaks. All human samples and one pork sample showed the specific multiple-locus variable-number tandem-repeat analysis (MLVA) profile 3-11-12-NA-0211, with at most two loci variations. Trace-back investigations suggested a link to a butcher's shop and a pig farm in the East Midlands. The investigations highlight the utility of molecular analysis (MLVA) in supporting epidemiological investigations of outbreaks caused by S. Typhimurium DT120. Safe handling and cooking of pork by food business operators and consumers are key interventions to prevent future outbreaks. PMID:23869962

  2. Targeted introduction of a diphtheria toxin resistant mutation into the chromosomal EF-2 locus of Pichia pastoris and expression of immunotoxin in the EF-2 mutants.

    PubMed

    Liu, Yuan Yi; Woo, Jung Hee; Neville, David M

    2003-08-01

    In an attempt to increase the production of a diphtheria toxin (DT) based immunotoxin by Pichia pastoris, we have created DT-resistant mutants that contain a substitution of arginine for glycine at position 701 in elongation factor 2 (EF-2). To achieve this, we first cloned and characterized the EF-2 gene (PEF1), and then made a construct pBLURA-Delta5'mutEF-2 that efficiently introduces specific mutations into the chromosomal EF-2 gene in P. pastoris by in vivo homologous recombination. pBLURA-Delta5(')mutEF-2 contains a selection marker URA3 and a 5' truncated form of the P. pastoris PEF1 that had been modified in vitro to carry the nucleotide mutations for the Gly(701) to Arg transition. Unlike the non-mutated strains, the EF-2 mutants are resistant to high-level intracellular expression of DT A chain that can catalyze the ADP-ribosylation. When used to express the secreted bivalent anti-T cell immunotoxin, A-dmDT390-bisFv(G4S), the EF-2 mutant strains showed increased viability compared to the non-mutated strains. However, they did not show an advantage over the non-mutated expressing strain in the production of the immunotoxin. Western blotting analysis revealed that although the EF-2 mutants did not increase the accumulation of intact A-dmDT390-bisFv(G4S) in the culture medium, they generated larger amounts of degraded products found in both the medium and cell pellets compared to the non-mutant expressing clone. In addition, double copy expression resulted in greater amounts of intact immunotoxin being retained within cellular compartments as well as degraded products. Based on these findings, we suggest that the secretory capacity may be rate limiting for divalent immunotoxin production in P. pastoris. PMID:12880776

  3. MpeR regulates the mtr efflux locus in Neisseria gonorrhoeae and modulates antimicrobial resistance by an iron-responsive mechanism.

    PubMed

    Mercante, Alexandra Dubon; Jackson, Lydgia; Johnson, Paul J T; Stringer, Virginia A; Dyer, David W; Shafer, William M

    2012-03-01

    Previous studies have shown that the MpeR transcriptional regulator produced by Neisseria gonorrhoeae represses the expression of mtrF, which encodes a putative inner membrane protein (MtrF). MtrF works as an accessory protein with the Mtr efflux pump, helping gonococci to resist high levels of diverse hydrophobic antimicrobials. Regulation of mpeR has been reported to occur by an iron-dependent mechanism involving Fur (ferric uptake regulator). Collectively, these observations suggest the presence of an interconnected regulatory system in gonococci that modulates the expression of efflux pump protein-encoding genes in an iron-responsive manner. Herein, we describe this connection and report that levels of gonococcal resistance to a substrate of the mtrCDE-encoded efflux pump can be modulated by MpeR and the availability of free iron. Using microarray analysis, we found that the mtrR gene, which encodes a direct repressor (MtrR) of mtrCDE, is an MpeR-repressed determinant in the late logarithmic phase of growth when free iron levels would be reduced due to bacterial consumption. This repression was enhanced under conditions of iron limitation and resulted in increased expression of the mtrCDE efflux pump operon. Furthermore, as judged by DNA-binding analysis, MpeR-mediated repression of mtrR was direct. Collectively, our results indicate that both genetic and physiologic parameters (e.g., iron availability) can influence the expression of the mtr efflux system and modulate levels of gonococcal susceptibility to efflux pump substrates. PMID:22214775

  4. The IGF2 Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insulin-like growth factor 2 (IGF2) is a peptide hormone regulating various cellular processes such as proliferation and apoptosis. IGF2 is vital to embryo development. The IGF2 locus covers approximately 150-kb genomic region on human chromosome 11, containing two imprinted genes, IGF2 and H19, sha...

  5. Molecular analysis of the mouse agouti gene and the role of dominant agouti-locus mutations in obesity and insulin resistance

    SciTech Connect

    Klebig, M.L.; Woychik, R.P.; Wilkinson, J.E.

    1994-09-01

    The lethal yellow (A{sup y/-}) and viable yellow (A{sup vy/-}) mouse agouti mutants have a predominantly yellow pelage and display a complex syndrome that includes obesity, hyperinsulinemia, and insulin resistance, hallmark features of obesity-associated noninsulin-dependent diabetes mellitus (NIDDM) in humans. A new dominant agouti allele, A{sup iapy}, has recently been identified; like the A{sup vy} allele, it is homozygous viable and confers obesity and yellow fur in heterozygotes. The agouti gene was cloned and characterized at the molecular level. The gene is expressed in the skin during hair growth and is predicted to encode a 131 amino acid protein, that is likely to be a secreted factor. In both Ay/- and A{sup iapy}/- mice, the obesity and other dominant pleiotropic effects are associated with an ectopic expression of agouti in many tissues where the gene product is normally not produced. In Ay, a 170-kb deletion has occurred that causes an upstream promoter to drive the ectopic expression of the wild-type agouti coding exons. In A{sup iapy}, the coding region of the gene is expressed from a cryptic promoter within the LTR of an intracisternal A-particle (IAP), which has integrated within the region just upstream of the first agouti coding exon. Transgenic mice ubiquitously expressing the cloned agouti gene under the influence of the beta-actin and phosphoglycerate kinase promoters display obesity, hyperinsulinemia, and yellow coat color. This demonstrates unequivocally that ectopic expression of agouti is responsible for the yellow obese syndrome.

  6. Locus equations are an acoustic expression of articulator synergy

    PubMed Central

    Iskarous, Khalil; Fowler, Carol A.; Whalen, D. H.

    2010-01-01

    The study investigated the articulatory basis of locus equations, regression lines relating F2 at the start of a Consonant-Vowel (CV) transition to F2 at the middle of the vowel, with C fixed and V varying. Several studies have shown that consonants of different places of articulation have locus equation slopes that descend from labial to velar to alveolar, and intercept magnitudes that increase in the opposite order. Using formulas from the theory of bivariate regression that express regression slopes and intercepts in terms of standard deviations and averages of the variables, it is shown that the slope directly encodes a well-established measure of coarticulation resistance. It is also shown that intercepts are directly related to the degree to which the tongue body assists the formation of the constriction for the consonant. Moreover, it is shown that the linearity of locus equations and the linear relation between locus equation slopes and intercepts originates in linearity in articulation between the horizontal position of the tongue dorsum in the consonant and to that in the vowel. It is concluded that slopes and intercepts of acoustic locus equations are measures of articulator synergy. PMID:20968373

  7. Ecology, Behavior and Bionomics: First Genotyping of Spodoptera frugiperda (J. E. Smith)(Lepidoptera: Noctuidae) Progeny from Crosses between Bt-Resistant and Bt-Susceptible Populations, and 65-Locus Discrimination of Isofami

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple sequence repeat (SSR) markers from Spodoptera frugiperda (J. E. Smith) were analyzed in crosses of this species between Bacillus thuringiensis (Berliner) (Bacillales: Bacillaceae) (Bt) resistant and susceptible populations to determine a possible association between markers and Bt resistance....

  8. Chromosomal locus for staphylococcal enterotoxin B.

    PubMed Central

    Shafer, W M; Iandolo, J J

    1978-01-01

    The genetic locus of staphylococcal enterotoxin B (SEB) was investigated in the Staphylococcus aureus food-poisoning isolates, strains S6 and 277. Direct neutral sucrose gradient centrifugation analysis of sodium dodecyl sulfate-sodium chloride-mediated cleared lysates demonstrated that strain S6 contained a single 37S plasmid. Transductional analysis revealed that the 37S plasmid in S6 encoded for cadmium resistance (Cad) but not SEB. Additionally, elimination of cadmium resistance in S6 provided a plasmid-negative derivative that produced SEB at the same level as the parent. Examination of strain 277 showed two plasmids, a 37S species encoding for penicillin resistance (Penr) and a 21S species containing the gene(s) responsible for tetracycline resistance (Tetr). Elimination of the 37S, penr plasmid in 277 had no effect on SEB production, whereas introduction of the 21S tetr plasmid via transformation into strain 8325 (SEB--) did not confer enterotoxigenesis upon the transformants. The data obtained in this investigation suggest that the SEB gene(s) in these food-poisoning isolates of S. aureus is chromosomal. Images PMID:669796

  9. Locus of Control and Interpersonal Attraction.

    ERIC Educational Resources Information Center

    Fagan, M. Michael

    1980-01-01

    The role of locus of control in interpersonal attraction was examined by administering 1) the Nowicki-Strickland Locus of Control Scale and 2) a sociometric test of friendship to 200 eighth graders. (CM)

  10. Linkage disequilibrium at the APA insecticidal seed protein locus of common bean (Phaseolus vulgaris L.)

    PubMed Central

    2010-01-01

    Background An interesting seed protein family with a role in preventing insect herbivory is the multi-gene, APA family encoding the α-amylase inhibitor, phytohemagglutinin and arcelin proteins of common bean (Phaseolus vulgaris). Variability for this gene family exists and has been exploited to breed for insect resistance. For example, the arcelin locus has been successfully transferred from wild to cultivated common bean genotypes to provide resistance against the bruchid species Zabrotes subfasciatus although the process has been hampered by a lack of genetic tools for and understanding about the locus. In this study, we analyzed linkage disequilibrium (LD) between microsatellite markers at the APA locus and bruchid resistance in a germplasm survey of 105 resistant and susceptible genotypes and compared this with LD in other parts of the genome. Results Microsatellite allele diversity was found to vary with each of the eight APA-linked markers analyzed, and two markers within the APA locus were found to be diagnostic for bruchid resistance or susceptibility and for the different arcelin alleles inherited from the wild accessions. Arc1 was found to provide higher levels of resistance than Arc5 and the markers in the APA locus were highly associated with resistance showing that introgression of this gene-family from wild beans provides resistance in cultivated beans. LD around the APA locus was found to be intermediate compared to other regions of the genome and the highest LD was found within the APA locus itself for example between the markers PV-atct001 and PV-ag004. Conclusions We found the APA locus to be an important genetic determinant of bruchid resistance and also found that LD existed mostly within the APA locus but not beyond it. Moderate LD was also found for some other regions of the genome perhaps related to domestication genes. The LD pattern may reflect the introgression of arcelin from the wild into the cultivated background through breeding. LD

  11. Locus of Control and Status Attainment.

    ERIC Educational Resources Information Center

    Bensman, Miriam Roza; Haller, Archibald O.

    Utilizing data derived from 277 rural, male respondents initially enrolled in Lenawee County, Michigan high schools, the Rotter's Internal-External Locus of Control Scale was employed to test the hypothesis that locus of control will have interactive rather than additive effects on the process of status attainment. Locus of control was defined as…

  12. Novel polycarboxylated EDTA-type cyclodextrins as ligands for lanthanide binding: study of their luminescence, relaxivity properties of Gd(iii) complexes, and PM3 theoretical calculations.

    PubMed

    Maffeo, Davide; Lampropoulou, Maria; Fardis, Michael; Lazarou, Yannis G; Mavridis, Irene M; Mavridou, Despoina A I; Urso, Elena; Pratsinis, Harris; Kletsas, Dimitris; Yannakopoulou, Konstantina

    2010-04-21

    Novel -type cyclodextrin (CD) derivatives, , and , bearing 6, 7 and 8 bis(carboxymethyl)amino (iminodiacetic acid) groups, respectively, were prepared, and their complexation with Eu(iii), Tb(iii) and Gd(iii) ions was studied. Luminescence titrations and mass spectrometry showed formation of multimetal complexes ( 2 to 3, mainly 3 and exactly 4 metal ions), whereas luminescence lifetime measurements revealed the presence of exchangeable water molecules. Semiempirical quantum mechanical calculations, performed by the PM3 method and assessed by DFT calculations on model ligands, indicated efficient multi-metal complexation, in agreement with the experiment. The structures showed coordination of the metal ions in the outer primary side of the CDs via 4 carboxylate O atoms, 2 N atoms and a glucopyranose O atom per metal ion. Coordination of water molecules was also predicted, in accordance with experimental results. Calculated bond lengths and angles were in agreement with literature experimental values of lanthanide complexes. Calculated energies showed that complex stability decreases in the order > > . (1)H NMR molecular relaxivity measurements for the Gd(iii) complexes of , or in water afforded values 4 to 10 times higher than the relaxivity of a commercial contrast agent at 12 MHz, and 6 to 20 times higher at 100 MHz. Solutions of and Gd(iii) complexes in human blood plasma displayed relaxivity values at 100 MHz 7 and 12 times, respectively, higher than the commercial agent. MTT tests of the Gd(iii) complexes using human skin fibroblasts did not show toxicity. Attempts to supramolecularly sensitize the luminescence of the lanthanide complexes using various aromatic CD guests were ineffective, evidently due to large guest-metal distances and inefficient inclusion. The described lanthanide complexes, could be useful as contrast agents in MRI. PMID:20449498

  13. Detection of a quantitative trait locus for both foliage and tuber resistance to late blight [Phytophthora infestans (Mont.) de Bary] on chromosome 4 of a dihaploid potato clone (Solanum tuberosum subsp. tuberosum).

    PubMed

    Bradshaw, John E; Hackett, Christine A; Lowe, Robert; McLean, Karen; Stewart, Helen E; Tierney, Irene; Vilaro, Marco D R; Bryan, Glenn J

    2006-09-01

    Linkage analysis, Kruskal-Wallis analysis, interval mapping and graphical genotyping were performed on a potato diploid backcross family comprising 120 clones segregating for resistance to late blight. A hybrid between the Solanum tuberosum dihaploid clone PDH247 and the long-day-adapted S. phureja clone DB226(70) had been crossed to DB226(70) to produce the backcross family. Eighteen AFLP primer combinations provided 186 and 123 informative maternal and paternal markers respectively, with 63 markers in common to both parents. Eleven microsatellite (SSR) markers proved useful for identifying chromosomes. Linkage maps of both backcross parents were constructed. The results of a Kruskal-Wallis analysis, interval mapping and graphical genotyping were all consistent with a QTL or QTLs for blight resistance between two AFLP markers 30 cM apart on chromosome 4, which was identified by a microsatellite marker. The simplest explanation of the results is a single QTL with an allele from the dihaploid parent conferring resistance to race 1, 4 of P. infestans in the foliage in the glasshouse and to race 1, 2, 3, 4, 6, 7 in the foliage in the field and in tubers from glasshouse raised plants. The QTL was of large effect, and explained 78 and 51% of the variation in phenotypic scores for foliage blight in the glasshouse and field respectively, as well as 27% of the variation in tuber blight. Graphical genotyping and the differences in blight scores between the parental clones showed that all of the foliage blight resistance is accounted for by chromosome 4, whereas undetected QTLs for tuber resistance probably exist on other chromosomes. Graphical genotyping also explained the lack of precision in mapping the QTL(s) in terms of lack of appropriate recombinant chromosomes. PMID:16845519

  14. Factors Determining Adolescent Locus of Control.

    ERIC Educational Resources Information Center

    Kopera-Frye, Karen F.; And Others

    Previous research has demonstrated an association between locus of control in adolescence and a successful transition to adulthood. Having an external locus of control has been implicated as an important factor in adolescent behaviors such as teenage pregnancy and delinquency, and has been found to be negatively related to school achievement. This…

  15. Locus of Control as a Mediator of College Students' Reactions to Teacher Compliance Attempts.

    ERIC Educational Resources Information Center

    Stewart, Robert A.; And Others

    A study was conducted to determine the effects of student locus of control on perceptions of and resistance to teacher influence attempts. Subjects, 302 college students, were provided with 22 sets of Behavior Alteration Messages and were instructed to rate on a 1-5 scale "how frequently your teacher uses statements of each type to get you to…

  16. Recombination at the Rp1 locus of maize.

    PubMed

    Hulbert, S H; Bennetzen, J L

    1991-05-01

    The Rp1 locus of maize determines resistance to races of the maize rust fungus (Puccinia sorghi). Restriction fragment length polymorphism markers that closely flank Rp1 were mapped and used to study the genetic fine structure and role of recombination in the instability of this locus. Susceptible progeny, lacking the resistance of either parent, were obtained from test cross progeny of several Rp1 heterozygotes. These susceptible progeny usually had non-parental genotypes at flanking marker loci, thereby verifying their recombinational origin. Seven of eight Rp1 alleles (or genes) studied were clustered within about 0.2 map units of each other. Rp1G, however, mapped from 1-3 map units distal to other Rp1 alleles. Rp5 also mapped distally to most Rp1 alleles. Other aspects of recombination at Rp1 suggested that some alleles carry duplicated sequences, that mispairing can occur, and that unequal crossing-over may be a common phenomenon in this region; susceptible progeny from an Rp1A homozygote had recombinant flanking marker genotypes, and susceptible progeny from an Rp1D/Rp1F heterozygote showed both possible nonparental flanking marker genotypes. PMID:1674815

  17. A locus on chromosome 7 determines myocardial cell necrosis and calcification (dystrophic cardiac calcinosis) in mice.

    PubMed Central

    Ivandic, B T; Qiao, J H; Machleder, D; Liao, F; Drake, T A; Lusis, A J

    1996-01-01

    Dystrophic cardiac calcinosis, an age-related cardiomyopathy that occurs among certain inbred strains of mice, involves myocardial injury, necrosis, and calcification. Using a complete linkage map approach and quantitative trait locus analysis, we sought to identify genetic loci determining dystrophic cardiac calcinosis in an F2 intercross of resistant C57BL/6J and susceptible C3H/HeJ inbred strains. We identified a single major locus, designated Dyscalc, located on proximal chromosome 7 in a region syntenic with human chromosomes 19q13 and 11p15. The statistical significance of Dyscalc (logarithm of odds score 14.6) was tested by analysis of permuted trait data. Analysis of BxH recombinant inbred strains confirmed the mapping position. The inheritance pattern indicated that this locus influences susceptibility of cells both to enter necrosis and to subsequently undergo calcification. Images Fig. 1 Fig. 3 PMID:8643601

  18. Fine Mapping and Introgressing a Fissure Resistance Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in rice kernels that increase breakage among kernels when transported or milled, which decrease the value of processed rice. This study employed molecular gene tagging methods to ...

  19. Evolutionary analysis of RB/Rpi-blb1 locus in the Solanaceae family.

    PubMed

    Xie, Zhengqing; Si, Weina; Gao, Rongchao; Zhang, Xiaohui; Yang, Sihai

    2015-12-01

    Late blight caused by the oomycete Phytophthora infestans is one of the most severe threats to potato production worldwide. Numerous studies suggest that the most effective protective strategy against the disease would be to provide potato cultivars with durable resistance (R) genes. However, little is known about the origin and evolutional history of these durable R-genes in potato. Addressing this might foster better understanding of the dynamics of these genes in nature and provide clues for identifying potential candidate R-genes. Here, a systematic survey was executed at RB/Rpi-blb1 locus, an exclusive broad-spectrum R-gene locus in potato. As indicated by synteny analysis, RB/Rpi-blb1 homologs were identified in all tested genomes, including potato, tomato, pepper, and Nicotiana, suggesting that the RB/Rpi-blb1 locus has an ancient origin. Two evolutionary patterns, similar to those reported on RGC2 in Lactuca, and Pi2/9 in rice, were detected at this locus. Type I RB/Rpi-blb1 homologs have frequent copy number variations and sequence exchanges, obscured orthologous relationships, considerable nucleotide divergence, and high non-synonymous to synonymous substitutions (Ka/Ks) between or within species, suggesting rapid diversification and balancing selection in response to rapid changes in the oomycete pathogen genomes. These characteristics may serve as signatures for cloning of late blight resistance genes. PMID:26008792

  20. Exercise Adherence and Locus of Control.

    ERIC Educational Resources Information Center

    Geshuri, Yosef; Glahn, Ronald

    In 1990, a study was conducted to investigate the relationship between students' locus of control and the extent to which they participated in a voluntary exercise program. First-time participants in the "Shape Up" program offered at the Porterville College Fitness Center during the summer and fall semesters of 1990 were identified through the…

  1. Locus of Control Differences and Marital Dissatisfaction.

    ERIC Educational Resources Information Center

    Doherty, William J.

    1981-01-01

    Studied the relationship between spouses' individual expectancies for internal versus external control of reinforcements (locus of control), and their level of marital dissatisfaction. Results indicated that only a marital pattern in which the wife was more external and the husband more internal was associated with marital dissatisfaction. (Author)

  2. The Measurement of Parenting Locus of Control.

    ERIC Educational Resources Information Center

    Kralj, M. M.; And Others

    The present study describes the construction of a scale for reliably measuring the extent to which parents form generalized expectancies of the degree to which their children's behaviors are contingent on their own actions as parents. The original 72 statements included in the Parenting Locus of Control (PLOC) scale ascribed cause to one of four…

  3. The Effect of Locus of Control and Locus of Reinforcement on Academic Task Persistence

    ERIC Educational Resources Information Center

    Morris, Susan; Messer, Stanley B.

    1978-01-01

    Examines the differential effectiveness of using external reinforcement versus self reinforcement to increase the task persistence of children characterized by internal or external locus of control. Subjects were 153 fourth and fifth grade boys. (BD)

  4. IlvHI locus of Salmonella typhimurium.

    PubMed

    Squires, C H; De Felice, M; Lago, C T; Calvo, J M

    1983-06-01

    In Escherichia coli K-12, the ilvHI locus codes for one of two acetohydroxy acid synthase isoenzymes. A region of the Salmonella typhimurium genome adjacent to the leucine operon was cloned on plasmid pBR322, yielding plasmids pCV47 and pCV49 (a shortened version of pCV47). This region contains DNA homologous to the E. coli ilvHI locus, as judged by hybridization experiments. Plasmid pCV47 did not confer isoleucine-valine prototrophy upon either E. coli or S. typhimurium strains lacking acetohydroxy acid synthase activity, suggesting that S. typhimurium lacks a functional ilvHI locus. However, isoleucine-valine prototrophs were readily isolated from such strains after mutagenesis with nitrosoguanidine. In one case we found that the Ilv+ phenotype resulted from an alteration in bacterial DNA on the plasmid (new plasmid designated pCV50). Furthermore, a new acetohydroxy acid synthase activity was observed in Ilv+ revertants; this enzyme was similar to E. coli acetohydroxy acid synthase III in its lack of activity at low pH. This new activity was correlated with the appearance in minicells of a new polypeptide having an approximate molecular weight of 61,000. Strains carrying either pCV49 or pCV50 produced a substantial amount of ilvHI-specific mRNA. These results, together with results from other laboratories, suggest that S. typhimurium has functional ilvB and ilvG genes and a cryptic ilvHI locus. E. coli K-12, on the other hand, has functional ilvB and ilvHI genes and a cryptic ilvG locus. PMID:6189818

  5. The Impact of Locus of Control on Language Achievement

    ERIC Educational Resources Information Center

    Nodoushan, Mohammad Ali Salmani

    2012-01-01

    This study hypothesized that students' loci of control affected their language achievement. 198 (N = 198) EFL students took the Rotter's (1966) locus of control test and were classified as locus-internal (ni = 78), and locus-external (ne = 120). They then took their ordinary courses and at the end of the semester, they were given their exams.…

  6. Locus of Control and Psychological Distress among the Aged.

    ERIC Educational Resources Information Center

    Hale, W. Daniel; And Others

    1986-01-01

    Examined relationship between locus of control and self-reported psychopathology in 139 residents of retirement complex. Correlation coefficients computed for locus of control and each of nine symptom dimensions of the Brief Symptom Inventory indicated that locus of control was correlated with self-reported psychopatholgoy for older women but not…

  7. Locus of Control: The Effect on Reading and Instructional Preference.

    ERIC Educational Resources Information Center

    Fisher, Richard I; Dyer, Barbara

    1978-01-01

    One hundred seventy-five college students were tested to determine the relationship among locus of control, student preference, and teaching procedures. Results showed that external locus of control students preferred hardware as instructional devices and that such devices improved their reading rates, while internal locus of control students…

  8. Self-Esteem, Locus of Control, and Student Achievement.

    ERIC Educational Resources Information Center

    Sterbin, Allan; Rakow, Ernest

    The direct effects of locus of control and self-esteem on standardized test scores were studied. The relationships among the standardized test scores and measures of locus of control and self-esteem for 12,260 students from the National Education Longitudinal Study 1994 database were examined, using the same definition of locus of control and…

  9. Toward an Abbreviated Internal-External Locus of Control Scale.

    ERIC Educational Resources Information Center

    Harris, Robert M., Jr.; Salomone, Paul R.

    1981-01-01

    Integrates a review of Rotter's theory with an analysis of the design and development of locus of control scales, and tests the reliability and validity of an abbreviated version of Rotter's Locus of Control Scale which provides practitioners with an instrument less confusing than other locus of control scales. (Author)

  10. The Lsktm1 Locus Modulates Lung and Skin Tumorigenesis in the Mouse

    PubMed Central

    Galvan, Antonella; Colombo, Francesca; Noci, Sara; Pazzaglia, Simonetta; Mancuso, Mariateresa; Manenti, Giacomo; Broman, Karl W.; Saran, Anna; Dragani, Tommaso A.

    2012-01-01

    Alleles derived from skin tumor−resistant Car-R mice provide resistance to both skin and lung tumorigenesis over the susceptibility of the SWR/J strain. In an effort to map tumor modifier loci affecting both tumor types, we carried out a genetic linkage analysis in backcross SWR/J x (SWR/J x Car-R) mice and identified a locus (Lsktm1) on chromosome 1 linked to both skin (LOD score = 3.93) and lung (LOD score = 8.74) tumorigenesis. Two genes, Igfbp5 and Igfbp2, residing in this locus and belonging to the insulin-like growth factor binding protein family were expressed at significantly greater levels in normal lung tissue from cancer-resistant Car-R mice than in cancer-susceptible SWR/J mice. Overexpression of the recombinant Igfbp5 and Igfbp2 genes in two lung cancer cell lines significantly inhibited clonogenicity (P < 0.0001). Collectively, we have identified a single polymorphic locus that affects skin and lung tumorigenesis and identify Igfbp5 and Igfbp2 as candidate modifier genes of lung tumorigenesis. PMID:22973541

  11. Bipolar disorder: Evidence for a major locus

    SciTech Connect

    Spence, M.A.; Flodman, P.L.; Sadovnick, A.D.; Ameli, H.

    1995-10-09

    Complex segregation analyses were conducted on families of bipolar I and bipolar II probands to delineate the mode of inheritance. The probands were ascertained from consecutive referrals to the Mood Disorder Service, University Hospital, University of British Columbia and diagnosed by DSM-III-R and Research Diagnostic Criteria. Data were available on over 1,500 first-degree relatives of the 186 Caucasian probands. The purpose of the analyses was to determine if, after correcting for age and birth cohort, there was evidence for a single major locus. Five models were fit to the data using the statistical package SAGE: (1) dominant, (2) recessive, (3) arbitrary mendelian inheritance, (4) environmental, and (5) no major effects. A single dominant, mendelian major locus was the best fitting of these models for the sample of bipolar I and II probands when only bipolar relatives were defined as affected (polygenic inheritance could not be tested). Adding recurrent major depression to the diagnosis {open_quotes}affected{close_quotes} for relatives reduced the evidence for a major locus effect. Our findings support the undertaking of linkage studies and are consistent with the analyses of the National Institutes of Mental Health (NIMH) Collaborative Study data by Rice et al. and Blangero and Elston. 39 refs., 4 tabs.

  12. TNXB locus may be a candidate gene predisposing to schizophrenia.

    PubMed

    Wei, J; Hemmings, G P

    2004-02-15

    We report here on the detection of nine single nucleotide polymorphisms (SNPs) near to the NOTCH4 locus in the search for schizophrenia susceptibility genes in the class III region of the human major histocompatibility complex (MHC). We totally analyzed 122 family trios recruited in the UK. The TDT analysis demonstrated that of the nine SNPs, three were associated with schizophrenia, including rs1009382 (P = 0.00047), rs204887 (P = 0.007), and rs8283 (P = 0.015). Both rs1009382 and rs204887 are present in the TNXB locus. The rs1009382 is a non-synonymous SNP located in exon 23 of the gene and its A to G base change causes a Glu2578Gly substitution. The goodness-of-fit test showed that genotypic distribution of rs1009382 was deviated from Hardy-Weinberg equilibrium due to homozygote excess in the patient group (P = 0.01), suggesting that a double dose of a genetic risk may be involved. Possibly, rs1009382 is a candidate SNP predisposing to a schizophrenic illness. Moreover, the test for linkage disequilibrium (LD) between paired SNPs showed that the nine SNPs studied may be in the same LD block with an unexpected pattern as the strength of LD was not correlated with the distance between paired SNPs. The haplotype analysis suggested that there might be more than one disease-related allele located in the class III region of the MHC, and that these alleles possibly confer either susceptibility or resistance to schizophrenia. PMID:14755442

  13. Locus Adh of Drosophila melanogaster under selection for delayed senescence

    SciTech Connect

    Khaustova, N.D.

    1995-05-01

    Dynamics of the Adh activity and frequencies of alleles Adh{sup F} and Adh{sup S} were analyzed under selection for delayed senescence. The experiments were performed on Drosophila melanogaster. Lines Adh{sup S}cn and Adh{sup F}vg and experimental populations cn` and vg`, selected for an increased duration of reproductive period (late oviposition) were used. Analysis of fertility, longevity, viability and resistance to starvation showed that selection for late oviposition resulted in delayed senescence of flies of the experimental populations. Genetic structure of population vg` changed considerably with regard to the Adh locus. This was confirmed by parameters of activity, thermostability, and electrophoretic mobility of the enzyme isolated from flies after 30 generations of selection. Analysis of frequencies of the Adh alleles showed that in both selected populations, which initially had different genetic composition, accumulated allele Adh{sup S}, which encodes the isozyme that is less active but more resistant to inactivation. Genetic mechanism of delayed senescence in Drosophila is assumed to involve selection at vitally important enzyme loci, including Adh. 18 refs., 2 tabs., 4 figs.

  14. Phase controlled colour tuning of samarium and europium complexes and excellent photostability of their PVA encapsulated materials. Structural elucidation, photophysical parameters and the energy transfer mechanism in the Eu(3+) complex by Sparkle/PM3 calculations.

    PubMed

    Dar, Wakeel Ahmed; Iftikhar, K

    2016-06-01

    Luminescent [Sm(acac)3(pyz)2] (1) and [Eu(acac)3(pyz)2] (2) complexes (acac is the anion of acetylacetone and pyz is pyrazine) have been synthesized and thoroughly characterized by microanalyses, TGA, DTA, IR, ESI-MS(+) and NMR spectroscopy. The photophysical properties of these complexes have been investigated. The Sparkle/PM3 model was utilized for predicting the ground-state geometry of (2). The Judd-Ofelt intensity parameters, radiative parameters, intramolecular energy transfer rates and quantum efficiency are calculated and discussed. The intramolecular energy transfer rates predict that the major energy transfer (96%) is from the ligand triplet state to the levels (5)D1 (74.53%) and (5)D0 (21.87%) of the Eu(3+) ion, in the complex. Complexes (1) and (2) were analysed for colour tuning properties and these show varying colours upon changing phases. This property would possibly allow the use of these complexes as 'colour indicators'. The photoluminescence and photostability of the thin hybrid films of both complexes (1) and (2) in polyvinyl alcohol (PVA) are investigated and discussed. The hybrid films of (1) and (2) are quite robust due to their higher photostability. An important feature of complex (2) is that the excitation window extends close to the visible range (393 nm). The lasing property of the Eu(3+) complex in various phases is also presented. PMID:27157414

  15. Molecular structures and conformations of 1-benzenesulphonyl-2-oxo-5-alkoxypyrrolidines with anti-amnesic activity. X-ray, 1H-NMR and quantum mechanical (PM3) studies

    NASA Astrophysics Data System (ADS)

    Amato, Maria E.; Bandoli, Giuliano; Dolmella, Alessandro; Grassi, Antonio; Pappalardo, Giuseppe C.; Toja, Emilio

    1991-04-01

    The crystal and molecular structures of the nootropic agents RU-47001 ((±) 1-(4-nitrobenzenesulphonyl)-2-oxo-5-ethoxypyrrolidine) and RU-47064 ((±) 1-(4-nitrobenzenesulphonyl)-2-oxo-5-isopropyloxypyrrolidine) have been determined by X-ray analysis and their solution conformation has been investigated using 1H NMR spectroscopy. The conformations of these molecules together with those of their analogues RU-35929 ((±) 1-benzenesulphonyl-2-oxo-5-ethoxypyrrolidine), RU-47010 ((±) 1-(3-pyridinylsulphonyl)-2-oxo-5-ethoxypyrrolidine) and RU-35965 ((±) 1-benzenesulphonyl-2-oxo-5-isopropyloxypyrrolidine) have been deduced from semi-quantitative PM3 type theoretical calculations. The main feature of all compounds consists of a common envelope conformation with C (4) at the flap of the pyrrolidinone ring in the solid, that in solution changes into the analogous, but opposite, possible puckered conformational isomer. The 5-alkoxy groups were found rather flexible in solution. Theoretical preferred conformations about NS and SC bonds were in acceptable agreement with those of the solid state. The calculated torsional energetics suggested that 1- 5 do not undergo conformational interconversion.

  16. β-Lactam antibiotics. Spectroscopy and molecular orbital (MO) calculations . Part I: IR studies of complexation in penicillin-transition metal ion systems and semi-empirical PM3 calculations on simple model compounds

    NASA Astrophysics Data System (ADS)

    Kupka, Teobald

    1997-12-01

    IR studies were preformed to determine possible transition metal ion binding sites of penicillin. the observed changes in spectral position and shape of characteristic IR bands of cloxacillin in the presence of transition metal ions (both in solutions and in the solid state) indicate formation of M-L complexes with engagement of -COO - and/or -CONH- functional groups. The small shift of νCO towards higher frequencies rules out direct M-L interaction via β-lactam carbonyl. PM3 calculations on simple model compounds (substituted formamide, cyclic ketones, lactams and substituted monocyclic β-lactams) have been performed. All structures were fully optimized and the calculated bond lengths, angles, heats of formation and CO stretching frequencies were discussed to determine the β-lactam binding sites and to explain its susceptibility towards nucleophilic attack (hydrolysis in vitro) and biological activity. The relative changes of calculated values were critically compared with available experimental data and same correlation between structural parameters and in vivo activity was shown.

  17. Multiple Disease Resistance in Plants.

    PubMed

    Wiesner-Hanks, Tyr; Nelson, Rebecca

    2016-08-01

    Many plants, both in nature and in agriculture, are resistant to multiple diseases. Although much of the plant innate immunity system provides highly specific resistance, there is emerging evidence to support the hypothesis that some components of plant defense are relatively nonspecific, providing multiple disease resistance (MDR). Understanding MDR is of fundamental and practical interest to plant biologists, pathologists, and breeders. This review takes stock of the available evidence related to the MDR hypothesis. Questions about MDR are considered primarily through the lens of forward genetics, starting at the organismal level and proceeding to the locus level and, finally, to the gene level. At the organismal level, MDR may be controlled by clusters of R genes that evolve under diversifying selection, by dispersed, pathogen-specific genes, and/or by individual genes providing MDR. Based on the few MDR loci that are well-understood, MDR is conditioned by diverse mechanisms at the locus and gene levels. PMID:27296142

  18. Finemapping of the arthritis QTL Pia7 reveals co-localization with Oia2 and the APLEC locus.

    PubMed

    Rintisch, C; Kelkka, T; Norin, U; Lorentzen, J C; Olofsson, P; Holmdahl, R

    2010-04-01

    In this study, we sought to determine the effect of the quantitative trait locus Pia7 on arthritis severity. The regulatory locus derived from the arthritis-resistant E3 rat strain was introgressed into the arthritis-susceptibility DA strain through continuous backcrossing. Congenic rats were studied for their susceptibility to experimental arthritis using pristane and adjuvant oil. In addition, cell number and function of various leukocyte populations were analyzed either under naive or stimulated conditions. We found that the minimal congenic fragment of DA.E3-Pia7 rats overlapped with the minimal fragment in DA.PVG-Oia2 congenic rats, which has been positionally cloned to the antigen-presenting lectin-like receptor complex (APLEC) genes. DA.E3-Pia7 congenic rats were protected from both PIA and OIA, but the protection was more pronounced in OIA. In adoptive transfer experiments we observed that the Pia7 locus controlled the priming of arthritogenic T cells and not the effector phase. In addition, Pia7 congenic rats had a significant higher frequency of B cells and granulocytes as well as TNFalpha production after stimulation, indicating a higher activation state of cells of the innate immune system. In conclusion, this study shows that the APLEC locus is a major locus regulating the severity of experimentally induced arthritis in rats. PMID:20200546

  19. Root Locus Algorithms for Programmable Pocket Calculators

    NASA Technical Reports Server (NTRS)

    Wechsler, E. R.

    1983-01-01

    Two algorithms are described which allow the plotting of individual points on a root locus diagram with or without time delay. The development was performed during the design of a continuous phase shifter used in the Baseband Antenna Combiner for the Deep Space Network (DSN). The algorithms, which are expected to be useful in similar DSN efforts, are simple enough to be implemented on a programmable pocket calculator. The coordinates of the open-loop zeros and poles, the gain constant K, and the time delay T are the data inputs.

  20. Clutter locus equation for more general linear array orientation

    NASA Astrophysics Data System (ADS)

    Bickel, Douglas L.

    2011-06-01

    The clutter locus is an important concept in space-time adaptive processing (STAP) for ground moving target indicator (GMTI) radar systems. The clutter locus defines the expected ground clutter location in the angle-Doppler domain. Typically in literature, the clutter locus is presented as a line, or even a set of ellipsoids, under certain assumptions about the geometry of the array. Most often, the array is assumed to be in the horizontal plane containing the velocity vector. This paper will give a more general 3-dimensional interpretation of the clutter locus for a general linear array orientation.

  1. Direct and indirect relationship between locus of control and depression.

    PubMed

    Yu, Xiaobo; Fan, Guanhua

    2016-07-01

    This study examined the mediating effect of self-esteem on the relationship between locus of control and depression among Chinese university students. In all, 457 students (232 men and 225 women) completed measures of locus of control, self-esteem, and depression. Correlational analyses indicated that external locus of control was related to self-esteem and depression, and self-esteem was related to depression. Structural equation modeling analysis showed that self-esteem partially mediated the influence of locus of control on depression. The significance of the results is discussed. PMID:25305190

  2. Molecular cloning of the c locus of Zea mays: a locus regulating the anthocyanin pathway.

    PubMed

    Paz-Ares, J; Wienand, U; Peterson, P A; Saedler, H

    1986-05-01

    The c locus of Zea mays, involved in the regulation of anthocyanin biosynthesis, has been cloned by transposon tagging. A clone (# 18En) containing a full size En1 element was initially isolated from the En element-induced mutable allele c-m668655. Sequences of clone # 18En flanking the En1 element were used to clone other c mutants, whose structure was predicted genetically. Clone #23En (isolated from c-m668613) contained a full size En1 element, clone #3Ds (isolated from c-m2) a Ds element and clone # 5 (isolated from c+) had no element on the cloned fragment. From these data we conclude that the clones obtained contain at least part of the c locus. Preliminary data on transcript analysis using a 1-kb DNA fragment from wild-type clone # 5 showed that at least three transcripts are encoded by that part of the locus, indicating that c is a complex locus. PMID:15957214

  3. Excited-state studies of polyacenes: A comparative picture using EOMCCSD, CR-EOMCCSD(T), range-separated (LR/RT)-TDDFT, TD-PM3 and TD-ZINDO

    SciTech Connect

    Lopata, Kenneth A.; Reslan, Randa; Kowalska, Malgorzata I.; Neuhauser, Daniel; Govind, Niranjan; Kowalski, Karol

    2011-11-08

    The low-lying excited states (L{sub a} and L{sub b}) of polyacenes from naphthalene to heptacene (N = 2-7) are studied using various time-dependent computational approaches. We perform high-level excited-state calculations using equation of motion coupled cluster with singles and doubles (EOMCCSD) and completely renormalized equation of motion coupled cluster with singles, doubles, and perturbative triples (CR-EOMCCSD(T)) and use these results to evaluate the performance of various range-separated exchange-correlation functionals within linearresponse (LR) and real-time (RT) time-dependent density functional theories (TDDFT). As has been reported recently, we find that the range-separated family of functionals address the well-documented TDDFT failures in describing these low-lying singlet excited states to a large extent and are as about as accurate as results from EOMCCSD on average. Real-time TDDFT visualization shows that the excited state charged densities are consistent with the predictions of the perimeter free electron orbital (PFEO) model. This corresponds to particle-on-a-ring confinement, which leads to the well-known red-shift of the excitations with acene length. We also use time-dependent semi-empirical methods like TD-PM3 and TD-ZINDO, which are capable of handling very large systems. Once re-parametrized to match the CR-EOMCCSD(T) results, TD-ZINDO becomes roughly as accurate as range-separated TDDFT, which opens the door to modeling systems such as large molecular assemblies.

  4. Regulatory Mutants at the his1 Locus of Yeast

    PubMed Central

    Lax, Carol; Fogel, Seymour; Cramer, Carole

    1979-01-01

    The his1 gene in Saccharomyces cerevisiae codes for phosphoribosyl transferase, an allosteric enzyme that catalyzes the initial step in histidine biosynthesis. Mutants that specifically alter the feedback regulatory function were isolated by selecting his1 prototrophic revertants that overproduce and excrete histidine. The prototrophs were obtained from diploids homoallelic for his1–7 and heterozygous for the flanking markers thr3 and arg6. Among six independently derived mutant isolates, three distinct levels of histidine excretion were detected. The mutants were shown to be second-site alterations mapping at the his1 locus by recovery of the original auoxtrophic parental alleles. The double mutants, HIS1–7e, are dominant with respect to catalytic function but recessive in regulatory function. When removed from this his1–7 background, the mutant regulatory site (HIS1–e) still confers prototrophy but not histidine excretion. To yield the excretion phenotype, the primary and altered secondary sites are required in cis array. Differences in histidine excretion levels correlate with resistance to the histidine analogue, triazoalanine. PMID:385447

  5. Reversion at the HIS1 Locus of Yeast

    PubMed Central

    Fogel, Seymour; Lax, Carol; Hurst, Donald D.

    1978-01-01

    The his1 gene (chromosome V) of Saccharomyces cerevisiae specifies phosphoribosyl transferase (E.C.2.4.2.17), the first enzyme of histidine biosynthesis. This hexameric enzyme has both catalytic and regulatory functions.—The spontaneous reversion rates of seven his1 mutations were studied. The reversion rates of the alleles at the proximal end of the locus (relative to the centromere) were about 50-fold higher than distal alleles.—Spontaneous reversion to prototrophy was studied in diploids homoallelic for each of the seven his1 mutations. Based on tetrad analysis, the prototrophy revertants could be assigned to three classes: (1) revertant tetrads that carried a prototrophic allele indistinguishable from wild type; (2) revertant tetrads that carried a prototrophic allele characterized by histidine excretion and feedback resistance; and (3) revertant tetrads that did not contain a prototrophic spore, but rather a newly derived allele that complemented the original allele intragenically. Four of the seven his1 mutations produced the excretor revertant class, and two mutations produced the complementer revertant class. The significance of these findings to our understanding of gene organization and the catalytic and regulatory functions of gene products are discussed. PMID:365679

  6. Locus of Control, and Expectational Set, on Two Aptitude Measures.

    ERIC Educational Resources Information Center

    Wildstein, Arlene B.; And Others

    The purpose of this study was to investigate whether there are differences between males and females on locus of control, if experimental instructions differentially affect the performance of internals as opposed to externals, and if locus of control differentially influences performance on distinct types of aptitude tests. The Children's…

  7. Anxiety, locus of control and appraisal of air pollution

    SciTech Connect

    Navarro, P.L.; Simpson-Housley, P.; de Man, A.F.

    1987-06-01

    100 residents of Santiago de Chile took part in a study of the relationship among locus of control, trait-anxiety, and perception of air pollution. Concern over the problem of atmospheric pollution and number of antipollution measures taken was related to trait-anxiety. Locus of control was associated with variation in awareness of pollution hazard.

  8. Physical structure of an endopolygalacturonase locus in peach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The melting flesh trait and the freestone trait are genetically linked to the same single locus in peach. Several studies have associated an endopolygalacturonase gene with this locus, either a deletion of endopolygalacturonase associated with the non-melting/clingstone phenotype or changes in the ...

  9. Changing Locus of Control: Steelworkers Adjusting to Forced Unemployment

    ERIC Educational Resources Information Center

    Legerski, Elizabeth Miklya; Cornwall, Marie; O'Neil, Brock

    2006-01-01

    Using an abbreviated version of Levenson's (1981) locus of control scale, we examine change over time in the locus of control of displaced steelworkers. The first data collection occurred approximately six months after plant shutdown, the second occurred a year later. Utilizing a multidimensional measurement model, we test the major assumption…

  10. Itpr3 Is responsible for the mouse tufted (tf) locus.

    PubMed

    Ellis, Hillary T; Tordoff, Michael G; Parker, M Rockwell

    2013-03-01

    The tf (tufted) locus is responsible for a classic phenotype of hair loss and regrowth in mice. It is a characteristic of the BTBR strain. Here, we use a combination of positional cloning methods and complementation mapping to identify Itpr3, the inositol triphosphate receptor type 3, as the gene responsible for the tf locus. PMID:23100490

  11. Locus of Control and the Effectiveness of Social Reinforcers

    ERIC Educational Resources Information Center

    Pawlicki, Robert E.

    1974-01-01

    This study tested the hypothesis that the developmental change in the effectiveness of social reinforcement was related to changes in locus of control. A total of 145 subjects in grades 3, 4, 6, and 7 responded to the Children's Locus of Control Scale and to a simple game of measuring the effectiveness of either praise connoting or information…

  12. Personality and Locus of Control among School Children

    ERIC Educational Resources Information Center

    Pandya, Archana A.; Jogsan, Yogesh A.

    2013-01-01

    The main purpose of this investigation is to find out the sex differences in personality traits and locus of control among school children. A total 60 children (30 boys and 30 girls) were taken as a sample. The research tool for personality, children personality questionnaire was used, which was made by Cattell and Porter. Locus of control was…

  13. The Shc locus regulates insulin signaling and adiposity in mammals

    PubMed Central

    Tomilov, Alexey A.; Ramsey, Jon J.; Hagopian, Kevork; Giorgio, Marco; Kim, Kyoungmi M.; Lam, Adam; Migliaccio, Enrica; Lloyd, Kent C.; Berniakovich, Ina; Prolla, Tomas A.; Pelicci, PierGiuseppe; Cortopassi, Gino A.

    2014-01-01

    Summary Longevity of a p66Shc knockout strain (ShcP) was previously attributed to increased stress resistance and altered mitochondria. Microarrays of ShcP tissues indicated alterations in insulin signaling. Consistent with this observation, ShcP mice were more insulin sensitive and glucose tolerant at organismal and tissue levels, as was a novel p66Shc knockout (ShcL). Increasing and decreasing Shc expression in cell lines decreased and increased insulin sensitivity, respectively – consistent with p66Shc's function as a repressor of insulin signaling. However, differences between the two p66Shc knockout strains were also observed. ShcL mice were fatter and susceptible to fatty diets, and their fat was more insulin sensitive than controls. On the other hand, ShcP mice were leaner and resisted fatty diets, and their adipose was less insulin sensitive than controls. ShcL and ShcP strains are both highly inbred on the C57Bl/6 background, so we investigated gene expression at the Shc locus, which encodes three isoforms, p66, p52, and p46. Isoform p66 is absent in both strains; thus, the remaining difference to which to attribute the ‘lean’ phenotype is expression of the other two isoforms. ShcL mice have a precise deletion of p66Shc and normal expression of p52 and p46Shc isoforms in all tissues; thus, a simple deletion of p66Shc results in a ‘fat’ phenotype. However, ShcP mice in addition to p66Shc deletion have a fourfold increase in p46Shc expression in white fat. Thus, p46Shc overexpression in fat, rather than p66Shc deletion, is the likely cause of decreased adiposity and reduced insulin sensitivity in the fat of ShcP mice, which has implications for the longevity of the strain. PMID:21040401

  14. A gene locus for targeted ectopic gene integration in Zymoseptoria tritici.

    PubMed

    Kilaru, S; Schuster, M; Latz, M; Das Gupta, S; Steinberg, N; Fones, H; Gurr, S J; Talbot, N J; Steinberg, G

    2015-06-01

    Understanding the cellular organization and biology of fungal pathogens requires accurate methods for genomic integration of mutant alleles or fluorescent fusion-protein constructs. In Zymoseptoria tritici, this can be achieved by integrating of plasmid DNA randomly into the genome of this wheat pathogen. However, untargeted ectopic integration carries the risk of unwanted side effects, such as altered gene expression, due to targeting regulatory elements, or gene disruption following integration into protein-coding regions of the genome. Here, we establish the succinate dehydrogenase (sdi1) locus as a single "soft-landing" site for targeted ectopic integration of genetic constructs by using a carboxin-resistant sdi1(R) allele, carrying the point-mutation H267L. We use various green and red fluorescent fusion constructs and show that 97% of all transformants integrate correctly into the sdi1 locus as single copies. We also demonstrate that such integration does not affect the pathogenicity of Z. tritici, and thus the sdi1 locus is a useful tool for virulence analysis in genetically modified Z. tritici strains. Furthermore, we have developed a vector which facilitates yeast recombination cloning and thus allows assembly of multiple overlapping DNA fragments in a single cloning step for high throughput vector and strain generation. PMID:26092798

  15. Genomic analysis reveals candidate genes for PPV resistance in apricot (Prunus armeniaca L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sharka disease, caused by Plum pox virus (PPV), is the most important disease affecting Prunus species. A major PPV resistance locus (PPVres) was previously mapped to the upper part of apricot (Prunus armeniaca) linkage group 1. In this study, a physical map of the PPVres locus in the PPV resistan...

  16. Genome Wide Analysis of Inbred Mouse Lines Identifies a Locus Containing Ppar-γ as Contributing to Enhanced Malaria Survival

    PubMed Central

    Henson, Kerstin; Luzader, Angelina; Lindstrom, Merle; Spooner, Muriel; Steffy, Brian M.; Suzuki, Oscar; Janse, Chris; Waters, Andrew P.; Zhou, Yingyao; Wiltshire, Tim; Winzeler, Elizabeth A.

    2010-01-01

    The genetic background of a patient determines in part if a person develops a mild form of malaria and recovers, or develops a severe form and dies. We have used a mouse model to detect genes involved in the resistance or susceptibility to Plasmodium berghei malaria infection. To this end we first characterized 32 different mouse strains infected with P. berghei and identified survival as the best trait to discriminate between the strains. We found a locus on chromosome 6 by linking the survival phenotypes of the mouse strains to their genetic variations using genome wide analyses such as haplotype associated mapping and the efficient mixed-model for association. This new locus involved in malaria resistance contains only two genes and confirms the importance of Ppar-γ in malaria infection. PMID:20531941

  17. Major histocompatibility complex locus DRA polymorphism in the endangered Sorraia horse and related breeds.

    PubMed

    Luís, C; Cothran, E G; Oom, M M; Bailey, E

    2005-02-01

    The major histocompatibility complex (MHC) genes play well-defined roles in eliciting immune responses and combating infectious diseases. This genetic system is among the most polymorphic. The extent of genetic variation within a population has been directly correlated with fitness for many traits. The MHC class II locus DRA polymorphism was analysed in the endangered Sorraia horse, two other Portuguese and four New World horse breeds considered to be historically close to the Sorraia. Comparison of the Sorraia with other breeds demonstrated less MHC variation among Sorraia horses. If DRA polymorphism provides greater disease resistance, selective breeding to increase MHC polymorphism may increase fitness of this population. PMID:16130491

  18. The Cajal Body and Histone Locus Body

    PubMed Central

    Nizami, Zehra; Deryusheva, Svetlana; Gall, Joseph G.

    2010-01-01

    The Cajal body (CB) is a nuclear organelle present in all eukaryotes that have been carefully studied. It is identified by the signature protein coilin and by CB-specific RNAs (scaRNAs). CBs contain high concentrations of splicing small nuclear ribonucleoproteins (snRNPs) and other RNA processing factors, suggesting that they are sites for assembly and/or posttranscriptional modification of the splicing machinery of the nucleus. The histone locus body (HLB) contains factors required for processing histone pre-mRNAs. As its name implies, the HLB is associated with the genes that code for histones, suggesting that it may function to concentrate processing factors at their site of action. CBs and HLBs are present throughout the interphase of the cell cycle, but disappear during mitosis. The biogenesis of CBs shows the features of a self-organizing structure. PMID:20504965

  19. Identifying a novel locus for psoriatic arthritis.

    PubMed

    Budu-Aggrey, Ashley; Bowes, John; Barton, Anne

    2016-01-01

    A number of studies have identified genetic risk loci for PsA, the majority of which also confer risk for psoriasis. The stronger heritability of PsA in comparison with psoriasis suggests that there should be risk loci that are specific for PsA. Identifying such loci could potentially inform therapy development to provide more effective treatments for PsA patients, especially with a considerable proportion being non-responsive to current therapies. Evidence of a PsA-specific locus has been previously found at HLA-B27 within the MHC region. A recent study has provided evidence of non-HLA risk loci that are specific for PsA at IL23R, PTPN22 and on chromosome 5q31. Functional characterization of these loci will provide further understanding of the pathways underlying PsA, and enable us to apply genetic findings for patient benefit. PMID:26255310

  20. Dental outpatients: health locus of control correlates.

    PubMed

    Ludenia, K; Donham, G W

    1983-11-01

    Examined relationships between the Multidimensional Health Locus of Control (MHLC) Scales, Beck Depression Inventory, Trait subscales of the State-Trait Personality Inventory, and dental ratings of oral hygiene and presence of periodontal disease with dental outpatients (N = 101) at a Veterans Administration Medical Center Dental Clinic. Results indicated that this sample of outpatients scored comparably on MHLC Health Internality and Health Externality to a sample reported by Wallston and Wallston. Older dental patients, in the present sample, scored significantly higher on Powerful Others Externality in contrast to younger Ss, which suggests greater reliance on health professionals for dental health. Confirmatory evidence is presented on the negative correlations of depression, anger, and anxiety with Health Internality. Differential approaches to dental treatment are discussed. PMID:6662936

  1. Identifying a novel locus for psoriatic arthritis

    PubMed Central

    Budu-Aggrey, Ashley; Bowes, John

    2016-01-01

    A number of studies have identified genetic risk loci for PsA, the majority of which also confer risk for psoriasis. The stronger heritability of PsA in comparison with psoriasis suggests that there should be risk loci that are specific for PsA. Identifying such loci could potentially inform therapy development to provide more effective treatments for PsA patients, especially with a considerable proportion being non-responsive to current therapies. Evidence of a PsA-specific locus has been previously found at HLA-B27 within the MHC region. A recent study has provided evidence of non-HLA risk loci that are specific for PsA at IL23R, PTPN22 and on chromosome 5q31. Functional characterization of these loci will provide further understanding of the pathways underlying PsA, and enable us to apply genetic findings for patient benefit. PMID:26255310

  2. Locus of Control Orientation: Parents, Peers, and Place.

    PubMed

    Ahlin, Eileen M; Lobo Antunes, Maria João

    2015-09-01

    An internal locus of control contributes to positive youth outcomes such as a general well-being and academic success, while also serving as a protective factor against exposure to community violence and reducing negative behaviors like violence. Despite these benefits, very little is known about antecedents of an internal locus of control orientation. Without an understanding of what factors contribute to the development of an internal locus of control, it is not clear how to best encourage its formation. This study uses data from the Project on Human Development in Chicago Neighborhoods to examine whether various mesosystem variables (family management strategies, peer interactions, neighborhood context, and individual-level characteristics) are associated with an internal locus of control orientation among 1,076 youth ages 9-19 living in 78 Chicago neighborhoods. Study participants were Hispanic (46 %), African American (34 %), and White (15 %), and 50 % were female. The findings suggest that, while most levels of the mesosystem influence locus of control orientation, family management strategies are more prominent determinants of an internal locus of control than peers, neighborhood context, or individual characteristics. Parental supervision over the time a youth spends at home and family socioeconomic status are consistent predictors of an internal locus of control, while harsh discipline is associated with an external locus of control. The discussion examines the import of various parenting techniques in shaping an internal locus of control and considers future avenues for research to further unpack how antecedents of locus of control can vary across youth. PMID:25617000

  3. A NK complex-linked locus restricts the spread of herpes simplex virus type 1 in the brains of C57BL/6 mice.

    PubMed

    Kastrukoff, Lorne F; Lau, Allen S; Takei, Fumio; Carbone, Francis R; Scalzo, Anthony A

    2015-11-01

    The most frequent cause of sporadic viral encephalitis in western countries is Herpes simplex virus (HSV). Despite treatment, mortality rates reach 20-30% while survivors often suffer from significant morbidity. In mice, resistance to lethal Herpes simplex encephalitis (HSE) is multifactorial and influenced by mouse and virus strain as well as route of infection. The ability to restrict viral spread in the brain is one factor contributing to resistance. After infection of the oral mucosa with HSV type 1 (HSV-1), virus spreads throughout the brains of susceptible strains but is restricted in resistant C57BL/6 mice. To further investigate restriction of viral spread in the brain, mendelian analysis was combined with studies of congenic, intra-natural killer complex (intra-NKC) recombinant and antibody-depleted mice. Results from mendelian analysis support the restriction of viral spread as a dominant trait and consistent with a single gene effect. In congenic mice, the locus maps to the NKC on chromosome 6 and is provisionally termed Herpes Resistance Locus 2 (Hrl2). In intra-NKC recombinants, the locus is further mapped to the segment Cd69 through D6Wum34; a different location from previously identified loci (Hrl and Rhs1) also associated with HSV-1 infection. Studies with antibody-depleted mice indicate the effect of this locus is mediated by NK1.1(+) expressing cells. This model increases our knowledge of lethal HSE, which may lead to new treatment options. PMID:25971711

  4. Validation of a major quantitative trait locus associated with host response to experimental infection with Porcine Reproductive and Respiratory Syndrome virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infectious diseases are costly to the swine industry and porcine reproductive and respiratory syndrome virus (PRRSV) is the most devastating. In earlier work, a quantitative trait locus associated with resistance/susceptibility to PRRSV was identified on Sus scrofa chromosome 4 (SSC4) using ~560 exp...

  5. Detecting purely epistatic multi-locus interactions by an omnibus permutation test on ensembles of two-locus analyses

    PubMed Central

    Wongseree, Waranyu; Assawamakin, Anunchai; Piroonratana, Theera; Sinsomros, Saravudh; Limwongse, Chanin; Chaiyaratana, Nachol

    2009-01-01

    Background Purely epistatic multi-locus interactions cannot generally be detected via single-locus analysis in case-control studies of complex diseases. Recently, many two-locus and multi-locus analysis techniques have been shown to be promising for the epistasis detection. However, exhaustive multi-locus analysis requires prohibitively large computational efforts when problems involve large-scale or genome-wide data. Furthermore, there is no explicit proof that a combination of multiple two-locus analyses can lead to the correct identification of multi-locus interactions. Results The proposed 2LOmb algorithm performs an omnibus permutation test on ensembles of two-locus analyses. The algorithm consists of four main steps: two-locus analysis, a permutation test, global p-value determination and a progressive search for the best ensemble. 2LOmb is benchmarked against an exhaustive two-locus analysis technique, a set association approach, a correlation-based feature selection (CFS) technique and a tuned ReliefF (TuRF) technique. The simulation results indicate that 2LOmb produces a low false-positive error. Moreover, 2LOmb has the best performance in terms of an ability to identify all causative single nucleotide polymorphisms (SNPs) and a low number of output SNPs in purely epistatic two-, three- and four-locus interaction problems. The interaction models constructed from the 2LOmb outputs via a multifactor dimensionality reduction (MDR) method are also included for the confirmation of epistasis detection. 2LOmb is subsequently applied to a type 2 diabetes mellitus (T2D) data set, which is obtained as a part of the UK genome-wide genetic epidemiology study by the Wellcome Trust Case Control Consortium (WTCCC). After primarily screening for SNPs that locate within or near 372 candidate genes and exhibit no marginal single-locus effects, the T2D data set is reduced to 7,065 SNPs from 370 genes. The 2LOmb search in the reduced T2D data reveals that four intronic SNPs

  6. Human Adenovirus Type 2 but Not Adenovirus Type 12 Is Mutagenic at the Hypoxanthine Phosphoribosyltransferase Locus of Cloned Rat Liver Epithelial Cells

    PubMed Central

    Paraskeva, Christos; Roberts, Carl; Biggs, Paul; Gallimore, Phillip H.

    1983-01-01

    Using resistance to the base analog 8-azaguanine as a genetic marker, we showed that adenovirus type 2, but not adenovirus type 12, is mutagenic at the hypoxanthine phosphoribosyltransferase locus of cloned diploid rat liver epithelial cells. Adenovirus type 2 increased the frequency of 8-azaguanine-resistant colonies by up to ninefold over the spontaneous frequency, depending on expression time and virus dose. PMID:6572280

  7. Low Cost Upper Atmosphere Sounder (LOCUS)

    NASA Astrophysics Data System (ADS)

    Gerber, Daniel; Swinyard, Bruce M.; Ellison, Brian N.; Aylward, Alan D.; Aruliah, Anasuya; Plane, John M. C.; Feng, Wuhu; Saunders, Christopher; Friend, Jonathan; Bird, Rachel; Linfield, Edmund H.; Davies, A. Giles; Parkes, Steve

    2014-05-01

    near future. We describe the current instrument configuration of LOCUS, and give a first preview of the expected science return such a mission would yield. The LOCUS instrument concept calls for four spectral bands, a first band at 4.7 THz to target atomic oxygen (O), a second band at 3.5 THz to target hydroxyl (OH), a third band at 1.1 THz to cover several diatomic species (NO, CO, O3, H2O) and finally a fourth band at 0.8 THz to retrieve pointing information from molecular oxygen (O2). LOCUS would be the first satellite instrument to measure atomic oxygen on a global scale with a precision that will allow the retrieval of the global O distribution. It would also be the first time that annual and diurnal changes in O are measured. This will be a significant step forward in understanding the chemistry and dynamics of the MLT. Current indications (derived from CRISTA measurement) lead us to believe that current models only give a poor representation of upper atmospheric O. The secondary target species can help us to address additional scientific questions related to both Climate (distribution of climate relevant gases, highly geared cooling of the MLT in response to Climate change, increased occurrence of Polar Mesospheric Clouds (PMC), etc) and Space Weather (precipitation of electrically charged particles and impact on NOx chemistry, fluctuations of solar Lyman-alpha flux through shown in the the distribution of photochemically active species, etc).

  8. Relation of organizational citizenship behavior and locus of control.

    PubMed

    Turnipseed, David L; Bacon, Calvin M

    2009-12-01

    The relation of organizational citizenship behavior and locus of control was assessed in a sample of 286 college students (52% men; M age = 24 yr.) who worked an average of 26 hr. per week. Measures were Spector's Work Locus of Control Scale and Podsakoff, et al.'s Organization Citizenship Behavior scale. Hierarchical multiple regressions indicated positive association of scores on work locus of control with scores on each of the four tested dimensions of organizational citizenship, as well as total organizational citizenship behavior. PMID:20099548

  9. Pseudohypoparathyroidism Type Ib Associated with Novel Duplications in the GNAS Locus

    PubMed Central

    Perez-Nanclares, Gustavo; Velayos, Teresa; Vela, Amaya; Muñoz-Torres, Manuel; Castaño, Luis

    2015-01-01

    Context Pseudohypoparathyroidism type 1b (PHP-Ib) is characterized by renal resistance to PTH (and, sometimes, a mild resistance to TSH) and absence of any features of Albright's hereditary osteodystrophy. Patients with PHP-Ib suffer of defects in the methylation pattern of the complex GNAS locus. PHP-Ib can be either sporadic or inherited in an autosomal dominant pattern. Whereas familial PHP-Ib is well characterized at the molecular level, the genetic cause of sporadic PHP-Ib cases remains elusive, although some molecular mechanisms have been associated with this subtype. Objective The aim of the study was to investigate the molecular and imprinting defects in the GNAS locus in two unrelated patients with PHP-Ib. Design We have analyzed the GNAS locus by direct sequencing, Methylation-Specific Multiplex Ligation-dependent Probe Amplification, microsatellites, Quantitative Multiplex PCR of Short Fluorescent fragments and array-Comparative Genomic Hybridization studies in order to characterize two unrelated families with clinical features of PHP-Ib. Results We identified two duplications in the GNAS region in two patients with PHP-Ib: one of them, comprising ∼320 kb, occurred ‘de novo’ in the patient, whereas the other one, of ∼179 kb in length, was inherited from the maternal allele. In both cases, no other known genetic cause was observed. Conclusion In this article, we describe the to-our-knowledge biggest duplications reported so far in the GNAS region. Both are associated to PHP-Ib, one of them occurring ‘de novo’ and the other one being maternally inherited. PMID:25710380

  10. Association of mercury resistance with antibiotic resistance in the gram-negative fecal bacteria of primates.

    PubMed Central

    Wireman, J; Liebert, C A; Smith, T; Summers, A O

    1997-01-01

    Gram-negative fecal bacterial from three longitudinal Hg exposure experiments and from two independent survey collections were examined for their carriage of the mercury resistance (mer) locus. The occurrence of antibiotic resistance was also assessed in both mercury-resistant (Hgr) and mercury-susceptible (Hgs) isolates from the same collections. The longitudinal studies involved exposure of the intestinal flora to Hg released from amalgam "silver" dental restorations in six monkeys. Hgr strains were recovered before the installation of amalgams, and frequently these became the dominant strains while amalgams were installed. Such persistent Hgr strains always carried the same mer locus throughout the experiments. In both the longitudinal and survey collections, certain mer loci were preferentially associated with one genus, whereas other mer loci were recovered from many genera. In general, strains with any mer locus were more likely to be multiresistant than were strains without mer loci; this clustering tendency was also seen for antibiotic resistance genes. However, the association of antibiotic multiresistance with mer loci was not random; regardless of source, certain mer loci occurred in highly multiresistant strains (with as many as seven antibiotic resistances), whereas other mer loci were found in strains without any antibiotic resistance. The majority of highly multiresistant Hgr strains also carried genes characteristic of an integron, a novel genetic element which enables the formation of tandem arrays of antibiotic resistance genes. Hgr strains lacking antibiotic resistance showed no evidence of integron components. PMID:9361435

  11. Genetic and Physiological Aspects of Resistance to 5-Fluoropyrimidines in Saccharomyces cerevisiae

    PubMed Central

    Jund, Richard; Lacroute, François

    1970-01-01

    Mutants resistant to 5-fluorouracil, 5-fluorocytosine, and 5-fluorouridine were selected in yeast, and the mechanisms of their resistance were investigated. The investigated mutations map in seven different loci. (i) A mutation at the locus FUI 1 gives specifically resistance to 5-fluorouridine. (ii) Two loci are involved in a specific 5-fluorocytosine resistance: a mutation at locus FCY 1 produces a loss of cytosine deaminase activity; a mutation at locus FCY 2 results in the loss of the activity of a cytosine-specific permease. (iii) A mutation at the locus FUR 4 gives a simultaneous resistance to 5-fluorouracil and to 5-fluorouridine by loss in the activity of the uracil-specific permease. (iv) We found three types of mutants in the locus FUR 1. One is dominant and weakly resistant to 5-fluorouracil, 5-fluorocytosine, and 5-fluorouridine. The two others are recessive and are unable to catalyze one of the steps involved in uracil transformation into uridine 5′-monophosphate; this block-age explains their strong resistance to 5-fluorouracil and 5-fluorocytosine. Of these two mutants, one is resistant to 5-fluorouridine and the other is not. (v) Mutations at locus FUR 2 give resistance to 5-fluorouracil, 5-fluorocytosine, and 5-fluorouridine. These mutations are dominant and lead to a loss in the feedback regulation of the aspartic transcarbamylase activity by uridine triphosphate. (vi) The mutants FUR 3 are resistant to 5-fluorocytosine and 5-fluorouridine. They are dominant and physiologically related to the mutants of the locus FUR 1 but their mechanism of resistance is not understood. PMID:5429721

  12. The Ink4a/Arf Locus Is a Barrier to Direct Neuronal Transdifferentiation

    PubMed Central

    Price, James D.; Park, Ki-Youb; Chen, Jiadong; Salinas, Ryan D.; Cho, Mathew J.; Kriegstein, Arnold R.

    2014-01-01

    Non-neurogenic cell types, such as cortical astroglia and fibroblasts, can be directly converted into neurons by the overexpression of defined transcription factors. Normally, the cellular phenotype of such differentiated cells is remarkably stable and resists direct cell transdifferentiation. Here we show that the Ink4a/Arf (also known as Cdkn2a) locus is a developmental barrier to direct neuronal transdifferentiation induced by transcription factor overexpression. With serial passage in vitro, wild-type postnatal cortical astroglia become progressively resistant to Dlx2-induced neuronal transdifferentiation. In contrast, the neurogenic competence of Ink4a/Arf-deficient astroglia is both greatly increased and does not diminish through serial cell culture passage. Electrophysiological analysis further demonstrates the neuronal identity of cells induced from Ink4a/Arf-null astroglia, and short hairpin RNA-mediated acute knockdown of p16Ink4a and p19Arf p16Ink4a and p19Arf indicates that these gene products function postnatally as a barrier to cellular transdifferentiation. Finally, we found that mouse fibroblasts deficient for Ink4a/Arf also exhibit greatly enhanced transcription factor-induced neuronal induction. These data indicate that Ink4a/Arf is a potent barrier to direct neuronal transdifferentiation and further suggest that this locus functions normally in the progressive developmental restriction of postnatal astrocytes. PMID:25209293

  13. Guidelines for establishing locus specific databases.

    PubMed

    Vihinen, Mauno; den Dunnen, Johan T; Dalgleish, Raymond; Cotton, Richard G H

    2012-02-01

    Information about genetic variation has been collected for some 20 years into registries, known as locus specific databases (LSDBs), which nowadays often contain information in addition to the actual genetic variation. Several issues have to be taken into account when considering establishing and maintaining LSDBs and these have been discussed previously in a number of articles describing guidelines and recommendations. This information is widely scattered and, for a newcomer, it would be difficult to obtain the latest information and guidance. Here, a sequence of steps essential for establishing an LSDB is discussed together with guidelines for each step. Curators need to collect information from various sources, code it in systematic way, and distribute to the research and clinical communities. In doing this, ethical issues have to be taken into account. To facilitate integration of information to, for example, analyze genotype-phenotype correlations, systematic data representation using established nomenclatures, data models, and ontologies is essential. LSDB curation and maintenance comprises a number of tasks that can be managed by following logical steps. These resources are becoming ever more important and new curators are essential to ensure that we will have expertly curated databases for all disease-related genes in the near future. PMID:22052659

  14. The lta4h Locus Modulates Susceptibility to Mycobacterial Infection in Zebrafish and Humans

    PubMed Central

    Tobin, David M.; Vary, Jay C.; Ray, John P.; Walsh, Gregory S.; Dunstan, Sarah J.; Bang, Nguyen D.; Hagge, Deanna A.; Khadge, Saraswoti; King, Mary-Claire; Hawn, Thomas R.; Moens, Cecilia B.; Ramakrishnan, Lalita

    2010-01-01

    SUMMARY Exposure to Mycobacterium tuberculosis produces varied early outcomes, ranging from resistance to infection to progressive disease. Here we report results from a forward genetic screen in zebrafish larvae that identify multiple mutant classes with distinct patterns of innate susceptibility to Mycobacterium marinum. A hypersusceptible mutant maps to the lta4h locus encoding leukotriene A4 hydrolase, which catalyzes the final step in the synthesis of leukotriene B4 (LTB4), a potent chemoattractant and proinflammatory eicosanoid. lta4h mutations confer hypersusceptibility independent of LTB4 reduction, by redirecting eicosanoid substrates to anti-inflammatory lipoxins. The resultant anti-inflammatory state permits increased mycobacterial proliferation by limiting production of tumor necrosis factor. In humans, we find that protection from both tuberculosis and multibacillary leprosy is associated with heterozygosity for LTA4H polymorphisms that have previously been correlated with differential LTB4 production. Our results suggest conserved roles for balanced eicosanoid production in vertebrate resistance to mycobacterial infection. PMID:20211140

  15. Changing Expectancies: A Counseling Model Based on Locus of Control.

    ERIC Educational Resources Information Center

    Connolly, Sean G.

    1980-01-01

    Presents counseling and communication techniques for giving external expectancies the internal direction necessary to facilitate behavior change. Locus of control expectancies provide a useful concept for assessing and influencing the behavior of unmotivated clients. (Author)

  16. Inheritance of Race-Specific Resistance to Xanthomonas campestris pv. campestris in Brassica Genomes.

    PubMed

    Vicente, J G; Taylor, J D; Sharpe, A G; Parkin, I A P; Lydiate, D J; King, G J

    2002-10-01

    ABSTRACT The inheritance of resistance to three Xanthomonas campestris pv. campestris races was studied in crosses between resistant and susceptible lines of Brassica oleracea (C genome), B. carinata (BC genome), and B. napus (AC genome). Resistance to race 3 in the B. oleracea doubled haploid line BOH 85c and in PI 436606 was controlled by a single dominant locus (Xca3). Resistance to races 1 and 3 in the B. oleracea line Badger Inbred-16 was quantitative and recessive. Strong resistance to races 1 and 4 was controlled by a single dominant locus (Xca1) in the B. carinata line PI 199947. This resistance probably originates from the B genome. Resistance to race 4 in three B. napus lines, cv. Cobra, the rapid cycling line CrGC5, and the doubled haploid line N-o-1, was controlled by a single dominant locus (Xca4). A set of doubled haploid lines, selected from a population used previously to develop a restriction fragment length polymorphism map, was used to map this locus. Xca4 was positioned on linkage group N5 of the B. napus A genome, indicating that this resistance originated from B. rapa. Xca4 is the first major locus to be mapped that controls race-specific resistance to X. campestris pv. campestris in Brassica spp. PMID:18944224

  17. Fixation probability in a two-locus intersexual selection model.

    PubMed

    Durand, Guillermo; Lessard, Sabin

    2016-06-01

    We study a two-locus model of intersexual selection in a finite haploid population reproducing according to a discrete-time Moran model with a trait locus expressed in males and a preference locus expressed in females. We show that the probability of ultimate fixation of a single mutant allele for a male ornament introduced at random at the trait locus given any initial frequency state at the preference locus is increased by weak intersexual selection and recombination, weak or strong. Moreover, this probability exceeds the initial frequency of the mutant allele even in the case of a costly male ornament if intersexual selection is not too weak. On the other hand, the probability of ultimate fixation of a single mutant allele for a female preference towards a male ornament introduced at random at the preference locus is increased by weak intersexual selection and weak recombination if the female preference is not costly, and is strong enough in the case of a costly male ornament. The analysis relies on an extension of the ancestral recombination-selection graph for samples of haplotypes to take into account events of intersexual selection, while the symbolic calculation of the fixation probabilities is made possible in a reasonable time by an optimizing algorithm. PMID:27059474

  18. [Health locus of control of patients in disease management programmes].

    PubMed

    Schnee, M; Grikscheit, F

    2013-06-01

    Health locus of control beliefs plays a major role in improving self-management skills of the chronically ill - a main goal in disease management programmes (DMP). This study aims at characterising participants in disease management regarding their health locus of control. Data are based on 4 cross-sectional postal surveys between spring and autumn of 2006 and 2007 within the Health Care Monitor of the Bertelsmann Foundation. Among the 6 285 respondents, 1 266 are chronically ill and not enrolled in a DMP and 327 are participating in a DMP. A high internal locus of control (HLC) occurs significantly less often in DMP patients than in normal chronically ill patients (and healthy people) controlling for age, gender and social class. With increasing age, a high internal locus of control is also significantly less likely. When comparing healthy people, the chronically ill and the DMP participants a social gradient of a high internal locus of control belief can be observed. The weaker internal and higher doctor-related external locus of control of DMP participants should be carefully observed by the physician when trying to strengthen the patients' self-management skills. Evaluators of DMP should take into account the different baselines of DMP patients and relevant control groups and incorporate these differences into the evaluation. PMID:22864845

  19. Neurolinguistic programming training, trait anxiety, and locus of control.

    PubMed

    Konefal, J; Duncan, R C; Reese, M A

    1992-06-01

    Training in the neurolinguistic programming techniques of shifting perceptual position, visual-kinesthetic dissociation, timelines, and change-history, all based on experiential cognitive processing of remembered events, leads to an increased awareness of behavioral contingencies and a more sensitive recognition of environmental cues which could serve to lower trait anxiety and increase the sense of internal control. This study reports on within-person and between-group changes in trait anxiety and locus of control as measured on the Spielberger State-Trait Anxiety Inventory and Wallston, Wallston, and DeVallis' Multiple Health Locus of Control immediately following a 21-day residential training in neurolinguistic programming. Significant with-in-person decreases in trait-anxiety scores and increases in internal locus of control scores were observed as predicted. Chance and powerful other locus of control scores were unchanged. Significant differences were noted on trait anxiety and locus of control scores between European and U.S. participants, although change scores were similar for the two groups. These findings are consistent with the hypothesis that this training may lower trait-anxiety scores and increase internal locus of control scores. A matched control group was not available, and follow-up was unfortunately not possible. PMID:1620774

  20. Two-locus linkage analysis in multiple sclerosis (MS)

    SciTech Connect

    Tienari, P.J. Univ. of Helsinki ); Terwilliger, J.D.; Ott, J. ); Palo, J. ); Peltonen, L. )

    1994-01-15

    One of the major challenges in genetic linkage analyses is the study of complex diseases. The authors demonstrate here the use of two-locus linkage analysis in multiple sclerosis (MS), a multifactorial disease with a complex mode of inheritance. In a set of Finnish multiplex families, they have previously found evidence for linkage between MS susceptibility and two independent loci, the myelin basic protein gene (MBP) on chromosome 18 and the HLA complex on chromosome 6. This set of families provides a unique opportunity to perform linkage analysis conditional on two loci contributing to the disease. In the two-trait-locus/two-marker-locus analysis, the presence of another disease locus is parametrized and the analysis more appropriately treats information from the unaffected family member than single-disease-locus analysis. As exemplified here in MS, the two-locus analysis can be a powerful method for investigating susceptibility loci in complex traits, best suited for analysis of specific candidate genes, or for situations in which preliminary evidence for linkage already exists or is suggested. 41 refs., 6 tabs.

  1. TaXA21-A1 on chromosome 5AL is associated with resistance to multiple pests in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A quantitative trait locus QYr.osu-5A on the long arm of chromosome 5A in bread wheat (Triticum aestivum L., 2n=6x=42; AABBDD) was previously reported to confer consistent resistance in adult plants to predominant stripe rust races, but the gene causing the quantitative trait locus (QTL) is not know...

  2. Sequence variations in the Boophilus microplus Bm86 locus and implications for immunoprotection in cattle vaccinated with this antigen.

    PubMed

    García-García, J C; Gonzalez, I L; González, D M; Valdés, M; Méndez, L; Lamberti, J; D'Agostino, B; Citroni, D; Fragoso, H; Ortiz, M; Rodríguez, M; de la Fuente, J

    1999-11-01

    Cattle tick infestations constitute a major problem for the cattle industry in tropical and subtropical regions of the world. Traditional control methods have been only partially successful, hampered by the selection of chemical-resistant tick populations. The Boophilus microplus Bm86 protein was isolated from tick gut epithelial cells and shown to induce a protective response against tick infestations in vaccinated cattle. Vaccine preparations including the recombinant Bm86 are used to control cattle tick infestations in the field as an alternative measure to reduce the losses produced by this ectoparasite. The principle for the immunological control of tick infestations relies on a polyclonal antibody response against the target antigen and, therefore, should be difficult to select for tick-resistant populations. However, sequence variations in the Bm86 locus, among other factors, could affect the effectiveness of Bm86-containing vaccines. In the present study we have addressed this issue, employing data obtained with B. microplus strains from Australia, Mexico, Cuba, Argentina and Venezuela. The results showed a tendency in the inverse correlation between the efficacy of the vaccination with Bm86 and the sequence variations in the Bm86 locus (R2 = 0.7). The mutation fixation index in the Bm86 locus was calculated and shown to be between 0.02 and 0.1 amino acids per year. Possible implications of these findings for the immunoprotection of cattle against tick infestations employing the Bm86 antigen are discussed. PMID:10668863

  3. The Salmonella typhimurium mar locus: molecular and genetic analyses and assessment of its role in virulence.

    PubMed Central

    Sulavik, M C; Dazer, M; Miller, P F

    1997-01-01

    The marRAB operon is a regulatory locus that controls multiple drug resistance in Escherichia coli. marA encodes a positive regulator of the antibiotic resistance response, acting by altering the expression of unlinked genes. marR encodes a repressor of marRAB transcription and controls the production of MarA in response to environmental signals. A molecular and genetic study of the homologous operon in Salmonella typhimurium was undertaken, and the role of marA in virulence in a murine model was assessed. Expression of E. coli marA (marAEC) present on a multicopy plasmid in S. typhimurium resulted in a multiple antibiotic resistance (Mar) phenotype, suggesting that a similar regulon exists in this organism. A genomic plasmid library containing S. typhimurium chromosomal sequences was introduced into an E. coli strain that was deleted for the mar locus and contained a single-copy marR'-'lacZ translational fusion. Plasmid clones that contained both S. typhimurium marR (marRSt) and marA (marASt) genes were identified as those that were capable of repressing expression of the fusion and which resulted in a Mar phenotype. The predicted amino acid sequences of MarRSt, MarASt, and MarBSt were 91, 86, and 42% identical, respectively, to the same genes from E. coli, while the operator/promoter region of the operon was 86% identical to the same 98-nucleotide-upstream region in E. coli. The marRAB transcriptional start sites for both organisms were determined by primer extension, and a marRABSt transcript of approximately 1.1 kb was identified by Northern blot analysis. Its accumulation was shown to be inducible by sodium salicylate. Open reading frames flanking the marRAB operon were also conserved. An S. typhimurium marA disruption strain was constructed by an allelic exchange method and compared to the wild-type strain for virulence in a murine BALB/c infection model. No effect on virulence was noted. The endogenous S. typhimurium plasmid that is associated with virulence

  4. Transcriptional Analysis of the Streptococcus pyogenes Salivaricin Locus

    PubMed Central

    Namprachan-Frantz, Phanramphoei; Rowe, Hannah M.; Runft, Donna L.

    2014-01-01

    The sal lantibiotic locus plays an important role in the virulence of Streptococcus pyogenes. Our transcriptional analysis of the sal locus provides new information on the complex regulation of this operon. Transcription of the operon is regulated by a promoter upstream of the operon and by a second internal promoter upstream of the salKRZ genes. Here we identify the location of the internal promoter and provide information on how this promoter is autoregulated by proteins within the locus. We determined by primer extension that the salKR promoter is located within the salY gene and identified several regulatory regions important for expression. The higher activity of the promoter in a salKR deletion strain indicates a role in repression by the SalR response regulator. Further, this promoter had higher activity in a salA deletion strain, implicating corepression or a signaling role for the SalA peptide. Finally, we demonstrate that this promoter can be controlled by host factors. Analysis of transcriptional regulation of this locus provides a better understanding of the function of the sal locus in S. pyogenes pathogenesis. PMID:24244008

  5. Pseudohypoparathyroidism type 1B caused by methylation changes at the GNAS complex locus.

    PubMed

    Poradosu, Sabrina; Bravenboer, Bert; Takatani, Rieko; Jüppner, Harald

    2016-01-01

    Pseudohypoparathyroidism type 1B (PHP1B) consists of a heterogeneous group of disorders characterised by resistance to parathyroid hormone (PTH). There are several different PHP1B subtypes that are all associated with methylation changes at GNAS. These epigenetic changes are caused by maternal deletions in GNAS or STX16, by paternal uniparental isodisomy of chromosome 20q (patUPD20q) or by undefined genetic mutations. The GNAS methylation changes are ultimately responsible for resistance to PTH signalling in the proximal renal tubules. However, there is no PTH resistance in the distal renal tubules nor in bone cells; consequently, patients with PHP1B have reduced urinary calcium excretion and can readily mobilise calcium (and phosphate) from the skeleton. We report a case of a sporadic PHP1B patient with broad GNAS methylation changes that were presumably caused by an unknown genetic mutation outside the GNAS locus. PTH resistance was preceded by several years by autoimmune negative hypothyroidism. Treatment consisted of calcium substitution and calcitriol. PMID:27170606

  6. Accessory Gene Regulator-1 Locus Is Essential for Virulence and Pathogenesis of Clostridium difficile

    PubMed Central

    Odo, Chioma; DuPont, Herbert L.

    2016-01-01

    ABSTRACT Clostridium difficile infection (CDI) is responsible for most of the definable cases of antibiotic- and hospital-associated diarrhea worldwide and is a frequent cause of morbidity and mortality in older patients. C. difficile, a multidrug-resistant anaerobic pathogen, causes disease by producing toxins A and B, which are controlled by an accessory gene regulator (Agr) quorum signaling system. Some C. difficile strains encode two Agr loci in their genomes, designated agr1 and agr2. The agr1 locus is present in all of the C. difficile strains sequenced to date, whereas the agr2 locus is present in a few strains. The functional roles of agr1 and agr2 in C. difficile toxin regulation and pathogenesis were unknown until now. Using allelic exchange, we deleted components of both agr loci and examined the mutants for toxin production and virulence. The results showed that the agr1 mutant cannot produce toxins A and B; toxin production can be restored by complementation with wild-type agr1. Furthermore, the agr1 mutant is able to colonize but unable to cause disease in a murine CDI model. These findings have profound implications for CDI treatment because we have uncovered a promising therapeutic target for the development of nonantibiotic drugs to treat this life-threatening emerging pathogen by targeting the toxins directly responsible for disease. PMID:27531912

  7. Locus coeruleus syndrome as a complication of tectal surgery.

    PubMed

    Kronenburg, Annick; Spliet, Wim G; Broekman, Marike; Robe, Pierre

    2015-01-01

    We describe a case of a 48-year-old woman who underwent a resection of a tectal pilocytic astrocytoma complicated by a sequence of fluctuating consciousness, psychosis with complex hallucinations and lasting sleeping disturbances in which she vividly acts out her dreams. Based on the clinical and anatomical evidence of this case, we propose the term locus coeruleus syndrome to describe this association of iatrogenic symptoms. Along with those of the locus coeruleus, lesions of the dorsal raphe nucleus, ventral tegmentum, substantia nigra pars compacta, the superior colliculus and other peduncular lesions (such as peduncular hallucinosis) are involved in the regulation of sleep-wake/arousal, behaviour, sleeping disorders and rapid eye movement atonia. However, iatrogenic lesion of the locus coeruleus could explain the complications on all levels in our patient. PMID:25903199

  8. Function and evolution of local repeats in the Firre locus

    PubMed Central

    Hacisuleyman, Ezgi; Shukla, Chinmay J.; Weiner, Catherine L.; Rinn, John L.

    2016-01-01

    More than half the human and mouse genomes are comprised of repetitive sequences, such as transposable elements (TEs), which have been implicated in many biological processes. In contrast, much less is known about other repeats, such as local repeats that occur in multiple instances within a given locus in the genome but not elsewhere. Here, we systematically characterize local repeats in the genomic locus of the Firre long noncoding RNA (lncRNA). We find a conserved function for the RRD repeat as a ribonucleic nuclear retention signal that is sufficient to retain an otherwise cytoplasmic mRNA in the nucleus. We also identified a repeat, termed R0, that can function as a DNA enhancer element within the intronic sequences of Firre. Collectively, our data suggest that local repeats can have diverse functionalities and molecular modalities in the Firre locus and perhaps more globally in other lncRNAs. PMID:27009974

  9. Bipartite Structure of the ade3 Locus of SACCHAROMYCES CEREVISIAE

    PubMed Central

    Jones, Elizabeth W.

    1977-01-01

    Forty ade3 mutants were examined with respect to their growth requirements, levels of the tetrahydrofolate interconversion enzymes, and/or map positions. Four deletions were detected. Mutations that result in a requirement for adenine and histidine map in one region of the locus; those which result in a requirement for adenine only map in a quite separate region of the locus, a region not disclosed in previous studies. No correlation was observed between growth properties of the strains and enzyme levels. PMID:324867

  10. Neighborhood Vigilance, Health Locus of Control, and Smoking Abstinence

    PubMed Central

    Reitzel, Lorraine R.; Lahoti, Sejal; Li, Yisheng; Cao, Yumei; Wetter, David W.; Waters, Andrew J.; Vidrine, Jennifer Irvin

    2012-01-01

    Objectives To examine whether health locus of control mediated relations of self-reported neighborhood vigilance and biochemically verified, continuous short-term smoking abstinence among 200 smokers enrolled in a cohort study. Methods A nonparametric bootstrapping procedure was used to assess mediation. Results Health locus of control-chance mediated relations between neighborhood vigilance and smoking abstinence in analyses adjusted for sociodemographics and tobacco dependence (p < .05). Greater vigilance was associated with greater attributions that health was affected by chance, which was associated with a lower likelihood of smoking abstinence. Conclusions Results suggest that neighborhood perceptions influence residents’ attributions for health outcomes, which can affect smoking abstinence. PMID:23985180