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1.
Patient Educ Couns ; 123: 108237, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38461793

ABSTRACT

OBJECTIVE: Given the importance of unhurried conversations for providing careful and kind care, we sought to create, test, and validate the Unhurried Conversations Assessment Tool (UCAT) for assessing the unhurriedness of patient-clinician consultations. METHODS: In the first two phases, the unhurried conversation dimensions were identified and transformed into an assessment tool. In the third phase, two independent raters used UCAT to evaluate the unhurriedness of 100 randomly selected consultations from 184 videos recorded for a large research trial. UCAT's psychometric properties were evaluated using this data. RESULTS: UCAT demonstrates content validity based on the literature and expert review. EFA and reliability analyses confirm its construct validity and internal consistency. The seven formative dimensions account for 89.93% of the variance in unhurriedness, each displaying excellent internal consistency (α > 0.90). Inter-rater agreement for the overall assessment item was fair (ICC = 0.59), with individual dimension ICCs ranging from 0.26 (poor) to 0.95 (excellent). CONCLUSION: UCAT components comprehensively assess the unhurriedness of consultations. The tool exhibits content and construct validity and can be used reliably. PRACTICE IMPLICATIONS: UCAT's design and psychometric properties make it a practical and efficient tool. Clinicians can use it for self-evaluations and training to foster unhurried conversations.


Subject(s)
Communication , Educational Measurement , Humans , Reproducibility of Results , Educational Measurement/methods , Psychometrics , Clinical Competence
2.
Neurosci Behav Physiol ; 52(2): 308-314, 2022.
Article in English | MEDLINE | ID: mdl-35317269

ABSTRACT

Diminazene is an anti-infection agent for animals and is a member of the diarylamidine group. This study reports the first detection of its inhibitory effect on AMPA-type ionotropic glutamate receptors. Experiments were carried out on isolated Wistar rat neurons: striatal giant cholinergic interneurons were used to study calcium-permeable AMPA receptors and hippocampal field CA1 pyramidal neurons were used to study calcium-impermeable AMPA receptors. Cells were isolated by vibrodissociation and currents were recorded by voltage clamping in the whole cell configuration. Diminazene produced concentration-dependent inhibition of currents evoked by application of kainate in both neuron types. IC50 values for calcium-permeable and calcium-impermeable AMPA receptors were 60 ± 11 and 160 ± 30 µM, respectively. Of note is that the inhibitory action of diminazene increased with increases in agonist concentration. The plot of the voltage dependence of inhibition at a fixed diminazene concentration for calcium-permeable AMPA receptors was biphasic: minimal inhibition was seen at positive potentials and maximum at -40 to -60 mV, while further hyperpolarization produced a gradual decrease in blockade efficacy. All these properties provide evidence that diminazene blocks AMPA receptor channels, perhaps with penetration through channels into cells.

3.
Front Pharmacol ; 12: 775040, 2021.
Article in English | MEDLINE | ID: mdl-34950035

ABSTRACT

The interest in AMPA receptors as a target for epilepsy treatment increased substantially after the approval of perampanel, a negative AMPA receptor allosteric antagonist, for the treatment of partial-onset seizures and generalized tonic-clonic seizures. Here we performed a screening for activity against native calcium-permeable AMPA receptors (CP-AMPARs) and calcium-impermeable AMPA receptors (CI-AMPARs) among different anticonvulsants using the whole-cell patch-clamp method on isolated Wistar rat brain neurons. Lamotrigine, topiramate, levetiracetam, felbamate, carbamazepine, tiagabin, vigabatrin, zonisamide, and gabapentin in 100-µM concentration were practically inactive against both major subtypes of AMPARs, while phenytoin reversibly inhibited them with IC50 of 30 ± 4 µM and 250 ± 60 µM for CI-AMPARs and CP-AMPARs, respectively. The action of phenytoin on CI-AMPARs was attenuated in experiments with high agonist concentrations, in the presence of cyclothiazide and at pH 9.0. Features of phenytoin action matched those of the CI-AMPARs pore blocker pentobarbital, being different from classical competitive inhibitors, negative allosteric inhibitors, and CP-AMPARs selective channel blockers. Close 3D similarity between phenytoin and pentobarbital also suggests a common binding site in the pore and mechanism of inhibition. The main target for phenytoin in the brain, which is believed to underlie its anticonvulsant properties, are voltage-gated sodium channels. Here we have shown for the first time that phenytoin inhibits CI-AMPARs with similar potency. Thus, AMPAR inhibition by phenytoin may contribute to its anticonvulsant properties as well as its side effects.

4.
Health Commun ; 36(14): 1990-2001, 2021 12.
Article in English | MEDLINE | ID: mdl-32847409

ABSTRACT

Many healthcare clinics encourage the use of online patient portals so that patients can have easier access to their health information, yet some patients are hesitant to interact with these portals. We used social cognitive theory to develop and test a theoretically grounded model that incorporates several (1) technological factors, (2) individual factors, and (3) social factors that influence individuals' post-adoption, active use of patient portals. Based on cross-sectional survey data from a sample of healthcare clinic patients (N = 431), we found that individuals' severity of illness predicted active use of patient portals and that trust in doctors predicted attitudes toward patient portals. Moreover, attitudes toward patient portals mediated the relationship between technology factors (i.e., perceived usefulness, ease of use, customization, and interactivity), and active use of patient portals. The paper concludes with a discussion of key findings, implications, and directions for future research.


Subject(s)
Patient Portals , Physicians , Cross-Sectional Studies , Delivery of Health Care , Humans , Psychological Theory
5.
Genomics ; 70(1): 140-9, 2000 Nov 15.
Article in English | MEDLINE | ID: mdl-11087671

ABSTRACT

We have previously reported a transcript of a novel mouse gene (Scrg1) with increased expression in transmissible spongiform encephalopathies and the cloning of the human mRNA analogue. In this paper, we present the genomic organization of the mouse and human SCRG1 loci, which exhibit a high degree of conservation. The genes are composed of three exons; the two downstream exons contain the protein coding region. The mouse gene is expressed in brain tissue essentially as a 0.7-kb message but also as a minor 2.6-kb mRNA. We have sequenced 20 kb of DNA at the mouse Scrg1 locus and found that the longer transcript is the prolongation of the 0.7-kb mRNA to a polyadenylation site located about 2 kb further downstream. Sequencing revealed that the mouse Scrg1 gene is physically linked to Sap30, a gene that encodes a protein of the histone deacetylase complex, and genetic linkage mapping assigned the localization of Scrg1 to chromosome 8 between Ant1 and Hmg2. Northern blot analysis showed that Scrg1 is under strict developmental control in mouse embryo and is expressed by cells of neuronal origin in vitro. Comparison of the rat, mouse, and human SCRG1 proteins identified a box of 35 identical contiguous amino acids and a characteristic cysteine distribution pattern defining a new protein signature.


Subject(s)
Genetic Linkage , Histone Deacetylases/genetics , Nerve Tissue Proteins/genetics , Neurons/chemistry , Amino Acid Sequence , Animals , Base Sequence , Cells, Cultured , Chromosome Mapping , Embryo, Mammalian , Genomic Library , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Neurons/cytology , Plant Proteins/genetics , RNA, Messenger , Rats , Sequence Homology, Amino Acid , Species Specificity , Tissue Distribution
6.
Mol Plant Microbe Interact ; 13(3): 287-96, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10707354

ABSTRACT

Anthracnose, one of the most important diseases of common bean (Phaseolus vulgaris), is caused by the fungus Colletotrichum lindemuthianum. A "candidate gene" approach was used to map anthracnose resistance quantitative trait loci (QTL). Candidate genes included genes for both pathogen recognition (resistance genes and resistance gene analogs [RGAs]) and general plant defense (defense response genes). Two strains of C. lindemuthianum, identified in a world collection of 177 strains, displayed a reproducible and differential aggressiveness toward BAT93 and JaloEEP558, two parental lines of P. vulgaris representing the two major gene pools of this crop. A reliable test was developed to score partial resistance in aerial organs of the plant (stem, leaf, petiole) under controlled growth chamber conditions. BAT93 was more resistant than JaloEEP558 regardless of the organ or strain tested. With a recombinant inbred line (RIL) population derived from a cross between these two parental lines, 10 QTL were located on a genetic map harboring 143 markers, including known defense response genes, anthracnose-specific resistance genes, and RGAs. Eight of the QTL displayed isolate specificity. Two were co-localized with known defense genes (phenylalanine ammonia-lyase and hydroxyproline-rich glycoprotein) and three with anthracnose-specific resistance genes and/or RGAs. Interestingly, two QTL, with different allelic contribution, mapped on linkage group B4 in a 5.0 cM interval containing Andean and Mesoamerican specific resistance genes against C. lindemuthianum and 11 polymorphic fragments revealed with a RGA probe. The possible relationship between genes underlying specific and partial resistance is discussed.


Subject(s)
Colletotrichum/pathogenicity , Fabaceae/genetics , Genes, Plant , Plant Diseases/genetics , Plants, Medicinal , Quantitative Trait, Heritable , Chromosome Mapping , Genotype , Plant Leaves/genetics , Plant Stems/genetics
7.
Brain Res Mol Brain Res ; 76(1): 173-9, 2000 Mar 10.
Article in English | MEDLINE | ID: mdl-10719228

ABSTRACT

The expression of the mRNA of nine scrapie responsive genes was analyzed in the brains of FVB/N mice infected with bovine spongiform encephalopathy (BSE). The RNA transcripts of eight genes were overexpressed to a comparable extent in both BSE-infected and scrapie-infected mice, indicating a common series of pathogenic events in the two transmissible spongiform encephalopathies (TSEs). In contrast, the serine proteinase inhibitor spi 2, an analogue of the human alpha-1 antichymotrypsin gene, was overexpressed to a greater extent in the brains of scrapie-infected animals than in animals infected with BSE, reflecting either an agent specific or a mouse strain specific response. The levels of spi 2 mRNA were increased during the course of scrapie prior to the onset of clinical signs of the disease and the increase reached 11 to 45 fold relative to uninfected controls in terminally ill mice. Spi 2, in common with four of the other scrapie responsive genes studied, is known to be associated with pro-inflammatory processes. These observations underline the importance of cell reactivity in TSE. In addition, scrg2 mRNA the level of which is enhanced in TSE-infected mouse brain, was identified as a previously unrecognized long transcript of the murine aldolase C gene. However, the level of the principal aldolase C mRNA is unaffected in TSE. The increased representation of the longer transcript in the late stage of the disease may reflect changes in mRNA processing and/or stability in reactive astrocytes or in damaged Purkinje cells.


Subject(s)
Brain/metabolism , Encephalopathy, Bovine Spongiform/metabolism , RNA, Messenger/metabolism , Scrapie/genetics , Animals , Base Sequence , Complement C1q/genetics , Complement C1q/metabolism , Encephalopathy, Bovine Spongiform/enzymology , Fructose-Bisphosphate Aldolase/genetics , Fructose-Bisphosphate Aldolase/metabolism , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Scrapie/enzymology , Scrapie/metabolism , Serine Proteinase Inhibitors/genetics , Serine Proteinase Inhibitors/metabolism
8.
Mol Plant Microbe Interact ; 12(9): 774-84, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10494630

ABSTRACT

The recent cloning of plant resistance (R) genes and the sequencing of resistance gene clusters have shed light on the molecular evolution of R genes. However, up to now, no attempt has been made to correlate this molecular evolution with the host-pathogen coevolution process at the population level. Cross-inoculations were carried out between 26 strains of the fungal pathogen Colletotrichum lindemuthianum and 48 Phaseolus vulgaris plants collected in the three centers of diversity of the host species. A high level of diversity for resistance against the pathogen was revealed. Most of the resistance specificities were overcome in sympatric situations, indicating an adaptation of the pathogen to the local host. In contrast, plants were generally resistant to allopatric strains, suggesting that R genes that were efficient against exotic strains but had been overcome locally were maintained in the plant genome. These results indicated that coevolution processes between the two protagonists led to a differentiation for resistance in the three centers of diversity of the host. To improve our understanding of the molecular evolution of these different specificities, a recombinant inbred (RI) population derived from two representative genotypes of the Andean (JaloEEP558) and Mesoamerican (BAT93) gene pools was used to map anthracnose specificities. A gene cluster comprising both Andean (Co-y; Co-z) and Mesoamerican (Co-9) host resistance specificities was identified, suggesting that this locus existed prior to the separation of the two major gene pools of P. vulgaris. Molecular analysis revealed a high level of complexity at this locus. It harbors 11 restriction fragment length polymorphisms when R gene analog (RGA) clones are used. The relationship between the coevolution process and diversification of resistance specificities at resistance gene clusters is discussed.


Subject(s)
Colletotrichum/pathogenicity , Fabaceae/genetics , Fabaceae/microbiology , Genes, Plant , Multigene Family , Plants, Medicinal , Amino Acid Sequence , Base Sequence , Biological Evolution , DNA Primers/genetics , Genetics, Population , Molecular Sequence Data , Plant Proteins/genetics , Virulence
9.
Genome ; 42(2): 254-64, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10231959

ABSTRACT

Co-2 is one of the R-genes against anthracnose identified in common bean. A RAPD marker, cloned as PvH20, was previously shown to contain 6 imperfect leucine-rich-repeats and to reveal a family of related sequences in the vicinity of the Co-2 locus. Using PvH20 as probe, a genomic clone and 2 partial cDNAs were isolated. DNA sequencing revealed that the 6.1 kb genomic fragment contains sequences encoding both NBS-LRR (ORF1) and kinase-like (ORF2) products. The 2 partial cDNAs (cD7 and cD8) belong to the NBS-LRR subfamily as do most of the resistance genes cloned to date. The LRR domain of ORF1 is interrupted by 2 stop codons suggesting that it corresponds to a non-functional member of the multigene family and ORF2 appears to be a kinase pseudogene. The 3 NBS-LRR polypeptides share a high level of amino acid identity and represent different members of a related family. By genetic mapping ORF1, cD7, and cD8 were found to span a genetic distance of 3 cM: cD8 maps at 2 cM from Co-2 and 3 cM from ORF1, cD7 maps at 1 cM from ORF1 and co-segregates with Co-2, thus cD7 might be a putative candidate for the Co-2 R-gene.


Subject(s)
Fabaceae/genetics , Plants, Medicinal , Proteins/genetics , Amino Acid Sequence , Base Sequence , Chromosome Mapping , Cloning, Molecular , DNA, Plant , Genes, Plant , Leucine-Rich Repeat Proteins , Molecular Sequence Data , Multigene Family , Open Reading Frames
10.
Arch Virol ; 144(1): 19-28, 1999.
Article in English | MEDLINE | ID: mdl-10076506

ABSTRACT

To identify the pathways involved in HIV-1 modification of cellular gene expression, chronically infected U937 cells were screened by mRNA differential display. A chimeric transcript consisting of the 3' end of the LTR of a HIV-1 provirus, followed by 3.7 kb of cellular RNA was identified suggesting that long readthrough transcription might be one of the mechanisms by which gene expression could be modified in individual infected cells. Such a phenomenon may also be the first step towards the potential transduction of cellular sequences. Furthermore, the mRNA encoding for the transcription factor Egr-1 was detected as an over-represented transcript in infected cells. Northern blot analysis confirmed the increase of Egr-1 mRNA content in both HIV-1 infected promonocytic U937 cells and T cell lines such as Jurkat and CEM. Interestingly a similar increase of Egr-1 mRNA has previously been reported to occur in HTLV-1 and HTLV-2 infected T cell lines. Despite the consistent increase in the level of Egr-1 mRNA, the amount of the encoded protein did not appear to be modified in HIV-1 infected cells, suggesting an increased turn over of the protein in chronically infected cells.


Subject(s)
DNA-Binding Proteins/genetics , Gene Expression Regulation, Viral , HIV Infections/genetics , HIV Long Terminal Repeat/genetics , HIV-1/physiology , Transcription Factors/genetics , Virus Replication/genetics , Cloning, Molecular , Early Growth Response Protein 1 , HIV Infections/virology , Humans , Immediate-Early Proteins/genetics , Molecular Sequence Data , U937 Cells
11.
J Biol Chem ; 273(29): 18015-8, 1998 Jul 17.
Article in English | MEDLINE | ID: mdl-9660755

ABSTRACT

We have recently described a novel mRNA denominated ScRG-1, the level of which is increased in the brains of Scrapie-infected mice (Dandoy-Dron, F., Guillo, F., Benboudjema, L., Deslys, J.-P., Lasmézas, C., Dormont, D., Tovey, M. G., and Dron, M. (1998) J. Biol. Chem. 273, 7691-7697). The increase in ScRG-1 mRNA in the brain follows the accumulation of PrPSc, the proteinase K-resistant form of the prion protein (PrP), and precedes the widespread neuronal death that occurs in late stage disease. In the present study, we have isolated a cDNA encoding the human counterpart of ScRG-1. Comparison of the human and mouse transcripts firmly established that both sequences encode a highly conserved protein of 98 amino acids that contains a signal peptide, suggesting that the protein may be secreted. Examination of the distribution of human ScRG-1 mRNA in adult and fetal tissues revealed that the gene was expressed primarily in the central nervous system as a 0.7-kilobase message and was under strict developmental control.


Subject(s)
Nerve Tissue Proteins/genetics , PrPSc Proteins/genetics , Prion Diseases/genetics , Adult , Animals , Base Sequence , Blotting, Northern , DNA, Complementary/chemistry , DNA, Complementary/isolation & purification , Endopeptidase K/metabolism , Humans , Mice , Mice, Inbred C57BL , Molecular Sequence Data , RNA, Messenger/chemistry , RNA, Messenger/isolation & purification
12.
Gene ; 212(2): 249-57, 1998 Jun 08.
Article in English | MEDLINE | ID: mdl-9611268

ABSTRACT

Higher plants contain a multigene family encoding proteins that share a highly conserved catalytic protein kinase domain about 70% identical to SHAGGY protein kinase (SGG) and glycogen synthase kinase-3 (GSK-3), respectively, from Drosophila and mammals. In this study we have characterized the structure and evolution of the Arabidopsis SHAGGY-related protein kinase (ASK) gene family. At least ten ASK genes are present per haploid genome of Arabidopsis. The genomic sequences of five ASK genes show a strikingly high conservation of intron positions and exon lengths. Phylogenetic analyses suggested that the Arabidopsis gene family contains at least three ancient classes of genes that diverged early in land plant evolution. The different classes may reflect specificity of substrates and/or biological functions. Eight out of the ten predicted ASK genes were mapped and shown to be dispersed over the five Arabidopsis chromosomes. A tentative model for the organization and evolution of the Arabidopsis ASK genes is presented.


Subject(s)
Arabidopsis Proteins , Arabidopsis/enzymology , Arabidopsis/genetics , Drosophila Proteins , Evolution, Molecular , Glycogen Synthase Kinase 3 , Multigene Family/genetics , Plant Proteins/genetics , Protein Kinases/genetics , Protein Serine-Threonine Kinases/genetics , Conserved Sequence , Models, Genetic , Molecular Sequence Data , Phylogeny , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Translocation, Genetic
13.
Curr Genet ; 33(4): 291-8, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9560437

ABSTRACT

The genome structure of Colletotrichum lindemuthianum in a set of diverse isolates was investigated using a combination of physical and molecular approaches. Flow cytometric measurement of genome size revealed significant variation between strains, with the smallest genome representing 59% of the largest. Southern-blot profiles of a cloned fungal telomere revealed a total chromosome number varying from 9 to 12. Chromosome separations using pulsed-field gel electrophoresis (PFGE) showed that these chromosomes belong to two distinct size classes: a variable number of small (< 2.5 Mb) polymorphic chromosomes and a set of unresolved chromosomes larger than 7 Mb. Two dispersed repeat elements were shown to cluster on distinct polymorphic minichromosomes. Single-copy flanking sequences from these repeat-containing clones specifically marked distinct small chromosomes. These markers were absent in some strains, indicating that part of the observed variability in genome organization may be explained by the presence or absence, in a given strain, of dispensable genomic regions and/or chromosomes.


Subject(s)
Ascomycota/genetics , Genome, Fungal , Ascomycota/pathogenicity , Base Sequence , DNA Fingerprinting , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Fungal/isolation & purification , Fabaceae/microbiology , Flow Cytometry , Genetic Markers , Genetic Variation , Karyotyping , Plants, Medicinal , Repetitive Sequences, Nucleic Acid , Telomere/genetics
14.
J Biol Chem ; 273(13): 7691-7, 1998 Mar 27.
Article in English | MEDLINE | ID: mdl-9516475

ABSTRACT

To define genes associated with or responsible for the neurodegenerative changes observed in transmissible spongiform encephalopathies, we analyzed gene expression in scrapie-infected mouse brain using "mRNA differential display." The RNA transcripts of eight genes were increased 3-8-fold in the brains of scrapie-infected animals. Five of these genes have not previously been reported to exhibit increased expression in this disease: cathepsin S, the C1q B-chain of complement, apolipoprotein D, and two previously unidentified genes denominated scrapie-responsive gene (ScRG)-1 and ScRG-2, which are preferentially expressed in brain tissue. Increased expression of the three remaining genes, beta2 microglobulin, F4/80, and metallothionein II, has previously been reported to occur in experimental scrapie. Kinetic analysis revealed a concomitant increase in the levels of ScRG-1, cathepsin S, the C1q B-chain of complement, and beta2 microglobulin mRNA as well as glial fibrillary acidic protein and F4/80 transcripts, markers of astrocytosis and microglial activation, respectively. In contrast, the level of ScRG-2, apolipoprotein D, and metallothionein II mRNA was only increased at the terminal stage of the disease. ScRG-1 mRNA was found to be preferentially expressed in glial cells and to code for a short protein of 47 amino acids with a strong hydrophobic N-terminal region.


Subject(s)
Gene Expression Regulation , Microglia/pathology , Nerve Tissue Proteins/genetics , RNA, Messenger/metabolism , Scrapie/genetics , Amino Acid Sequence , Animals , Apolipoproteins/genetics , Apolipoproteins D , Base Sequence , Brain/virology , Cathepsins/genetics , Cloning, Molecular , Complement C1q/genetics , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Scrapie/pathology , Transcription, Genetic
15.
Mol Plant Microbe Interact ; 11(2): 99-108, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9450334

ABSTRACT

A random insertional mutagenesis in Colletotrichum lindemuthianum, the causal agent of common bean anthracnose, generated four mutants that showed altered pathogenicity when tested on intact seedlings, excised leaves, and/or excised hypocotyls. One of these mutants, H290, produced very few lesions on bean leaves and appeared affected in its ability to penetrate the leaf cuticle. Molecular analyses showed that the border sequences of the unique integration site of the disrupting pAN7-1 plasmid in the mutant exhibited homology with conserved domains of serine/threonine protein kinases. The corresponding wild-type sequences were cloned and a gene replacement vector with a mutated copy harboring a selection marker constructed. Transformation of the wild-type pathogen produced a strain with a phenotype identical to the original mutant. Genomic and cDNA sequences indicated that the disrupted gene is a member of the serine/threonine protein kinase family. The gene, called clk1 (Colletotrichum lindemuthianum kinase 1), was weakly expressed in the mycelium of the wild-type strain grown on rich and minimal synthetic media but was undetectable during the infection even when a sensitive reverse transcriptase-polymerase chain reaction methodology was used. This study represents the first characterization of altered pathogenicity mutants in C. lindemuthianum produced by random mutagenesis and demonstrates the involvement of a member of the serine/threonine kinase gene family in the early steps of the infection process.


Subject(s)
Caenorhabditis elegans Proteins , Fabaceae/microbiology , Helminth Proteins/genetics , Mitosporic Fungi/pathogenicity , Plants, Medicinal , Amino Acid Sequence , Base Sequence , DNA, Recombinant , Genetic Vectors , Helminth Proteins/metabolism , Molecular Sequence Data , Mutagenesis, Insertional , Phenotype , Sequence Homology, Amino Acid , Virulence/genetics
16.
Theor Appl Genet ; 96(3-4): 494-502, 1998 Mar.
Article in English | MEDLINE | ID: mdl-24710889

ABSTRACT

Molecular markers offer new opportunities for breeding for disease resistance. Resistance gene pyramiding in a single cultivar, as a strategy for durable resistance, can be facilitated by marker-assisted selection (MAS). A RAPD marker, ROH20(450), linked to the Mesoamerican Co-2 anthracnose resistance gene, was previously transformed into a SCAR marker, SCH20. In the present paper we have further characterized the relevance of the SCH20 SCAR marker in different genetic backgrounds. Since this SCAR marker was found to be useful mainly in the Andean gene pool, we identified a new PCR-based marker (SCAreoli) for indirect scoring of the presence of the Co-2 gene. The SCAreoli SCAR marker is polymorphic in the Mesoamerican as well as in the Andean gene pool and should be useful in MAS. We also report that PvH20, the cloned sequence corresponding to the 450-bp RAPD marker ROH20(450), contains six imperfect leucine-rich repeats, and reveals a family of related sequences in the vicinity of the Co-2 locus. These results are discussed in the context of the recent cloning of some plant resistance genes.

17.
Phytopathology ; 87(8): 807-13, 1997 Aug.
Article in English | MEDLINE | ID: mdl-18945048

ABSTRACT

ABSTRACT Population subdivision of Colletotrichum lindemuthianum, the causal agent of anthracnose, was studied in three regions located in three centers of diversity of its host, Phaseolus vulgaris. Random amplified polymorphic DNA (RAPD) markers, restriction endonuclease analysis of the amplified ribosomal internal transcribed spacer region, and virulence on a set of 12 cultivars were used to assess the genetic diversity of C. lindemuthianum strains isolated in Mexican, Ecuadorian, and Argentinean wild common bean populations. The three regions were significantly differentiated for molecular markers. For these markers, Mexico was the most polymorphic and the most distant from Ecuador and Argentina. The majority of the RAPD alleles present in Ecuador and Argentina were found in Mexico, suggesting that Andean populations have been derived from the Mesoamerican center. Pathogenicity tests on a set of 12 cultivars showed that all but one of the Mexican strains were virulent exclusively on Mesoamerican cultivars. Argentinean strains were virulent preferentially on southern Andes cultivars, and the Ecuadorian strains, except for one strain, were avirulent on all cultivars. These results suggest an adaptation of strains on cultivars of the same geographic origin. Thus, based on molecular and virulence markers, C. lindemuthianum strains isolated from wild common bean populations were divided into three groups corresponding to host gene pools.

18.
J Neurovirol ; 2(4): 240-8, 1996 Aug.
Article in English | MEDLINE | ID: mdl-8799215

ABSTRACT

Creutzfeldt-Jakob Disease (CJD), a neurodegenerative and dementing disease of later life, is caused by a viruslike entity that is incompletely characterized. As in scrapie, all more purified infectious brain preparations contain nucleic acids. However, it has not been possible to visualize unique bands that may derive from a viral genome. We here used a subtractive strategy known as representational difference analysis (RDA) to uncover such sequences. To reduce the complexity of starting target nucleic acids, sucrose gradients were first used to select nuclease resistant particles with a defined 120S size. In CJD this single 120S gradient peak is highly enriched for infectivity, and contains reduced amounts of PrP (Proc. Natl. Acad. Sci. 92, 5124-8, 1995). Parallel 120S fractions from uninfected brain were made to generate subtractor sequences. 120S particles were lysed in GdnSCN, and ng amounts of released RNA were purified for random-primed cDNA synthesis. To capture representative fragments of 100-500 bp, cDNAs were cleaved with Mbo I for adaptor ligation and amplification. In the first experiment with moderate RDA selection, it was possible to visualize clones from CJD cDNA that did not hybridize to control cDNA. In the second experiment, more exhaustive subtractions yielded a discrete set of CJD derived gel bands. Competitive hybridization showed a subset of these bands were not present in either the control 120S cDNA or in the hamster genome. This represents the first demonstration of apparently CJD-specific nucleic acid bands in more purified infectious preparations. Although exhaustive cloning, sequencing and correlative titration studies need to be done, it is encouraging that most of the viral candidates selected thus far have no significant homology with any previously described sequence in the database.


Subject(s)
Creutzfeldt-Jakob Syndrome/genetics , Creutzfeldt-Jakob Syndrome/virology , DNA, Viral/analysis , Animals , Brain Chemistry/genetics , Cloning, Molecular , Cricetinae , DNA, Complementary/analysis , DNA, Complementary/isolation & purification , DNA, Viral/isolation & purification , Disease Models, Animal , Gene Amplification , Genetic Testing , Nucleic Acid Hybridization , Phosphorus Radioisotopes , Polymerase Chain Reaction
19.
Plant J ; 8(5): 763-70, 1995 Nov.
Article in English | MEDLINE | ID: mdl-8528287

ABSTRACT

A new Arabidopsis thaliana (ecotype Columbia) genomic library has been constructed in Yeast Artificial Chromosomes: the CIC library (for CEPH, INRA and CNRS). Optimization of plant culture conditions and protoplast preparation allowed the recovery of large amounts of viable protoplasts. Mechanical shearing of DNA was minimized by isolation of DNA from protoplasts embedded in agarose. Cloning of large inserts was favored by including two successive size fractionation steps (after partial EcoRI digestion and after ligation with the vector arms), which selected DNA fragments larger than 350 kb. The library consists of 1152 clones with an average insert size of 420 kb. Clones carrying chloroplast DNA and various nuclear repeated sequences have been identified. Twenty-one per cent of the clones are found to contain chloroplast DNA. Therefore, the library represents around four nuclear genome equivalents. The clones containing 5S rDNA genes, 18S-25S rDNA sequences and the 180 bp paracentromeric repeated element account for 3.6%, 8.9% and 5.8%, respectively. Only one clone was found to carry the 160 bp paracentromeric repeated element. Given the smaller size of clones carrying Arabidopsis repeated DNA, the average size of remaining clones is around 480 kb. The library was screened by PCR amplification using pairs of primers corresponding to sequences dispersed in the genome. Seventy out of 76 pairs of primers identified from one to seven YAC clones. Thus at least 92% of the genome is represented in the CIC library. The survey of the library for clones containing unlinked DNA sequences indicates that the proportion of chimeric clones is lower than 10%.


Subject(s)
Arabidopsis/genetics , Chromosomes, Artificial, Yeast , Genomic Library , Cell Nucleus/genetics , Centromere , Cloning, Molecular/methods , DNA Probes , DNA, Chloroplast/genetics , DNA, Plant/genetics , Electrophoresis, Gel, Pulsed-Field , Human Genome Project , Protoplasts , Repetitive Sequences, Nucleic Acid
20.
Genome ; 37(6): 915-24, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7828839

ABSTRACT

A bean genetic map was developed to locate resistance genes against anthracnose and genes involved in plant defense mechanisms. One hundred and fifty-seven markers (51 restriction fragment length polymorphism, 100 random amplified polymorphic DNA, 2 sequence characterized amplified regions, and 4 morphological markers) were used to construct a genetic map covering 567.5 cM of the bean genome. Morphological markers consisted in two resistance genes towards anthracnose (Are and RVI), a dominant gene for nuclear male sterility (Ms8) and a pod-shape character (SGou). This map was established by using a backcross population (BC1) of 128 individuals, derived from a cross between two European bean genotypes: Ms8EO2 and Corel. Nine percent of the markers showed segregation distortions and mapped to three regions. Clusters of 2-10 markers were observed in every linkage group. The possible origin of these clusters is discussed. Nineteen markers shared with a previously published bean linkage map allowed us to establish a preliminary correspondence between the two maps. Finally, seven genes involved in plant defense mechanisms were located on this map.


Subject(s)
Chromosome Mapping , Fabaceae/genetics , Genes, Plant/genetics , Mitosporic Fungi , Plant Diseases , Plants, Medicinal , Base Sequence , Crosses, Genetic , Fabaceae/microbiology , Fabaceae/physiology , Genetic Linkage/genetics , Genetic Markers , Molecular Sequence Data , Plant Diseases/microbiology , Polymerase Chain Reaction/methods , Polymorphism, Genetic , Polymorphism, Restriction Fragment Length
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