Neuroanatomical Study of the A11 Diencephalospinal Pathway in the Non-Human Primate

BACKGROUND: The A11 diencephalospinal pathway is crucial for sensorimotor integration and pain control at the spinal cord level. When disrupted, it is thought to be involved in numerous painful conditions such as restless legs syndrome and migraine. Its anatomical organization, however, remains largely unknown in the non-human primate (NHP). We therefore characterized the anatomy of this pathway in the NHP. METHODS AND FINDINGS: In situ hybridization of spinal dopamine receptors showed that D1 receptor mRNA is absent while D2 and D5 receptor mRNAs are mainly expressed in the dorsal horn and D3 receptor mRNA in both the dorsal and ventral horns. Unilateral injections of the retrograde tracer Fluoro-Gold (FG) into the cervical spinal enlargement labeled A11 hypothalamic neurons quasi-exclusively among dopamine areas. Detailed immunohistochemical analysis suggested that these FG-labeled A11 neurons are tyrosine hydroxylase-positive but dopa-decarboxylase and dopamine transporter-negative, suggestive of a L-DOPAergic nucleus. Stereological cell count of A11 neurons revealed that this group is composed by 4002±501 neurons per side. A 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) intoxication with subsequent development of a parkinsonian syndrome produced a 50% neuronal cell loss in the A11 group. CONCLUSION: The diencephalic A11 area could be the major source of L-DOPA in the NHP spinal cord, where it may play a role in the modulation of sensorimotor integration through D2 and D3 receptors either directly or indirectly via dopamine formation in spinal dopa-decarboxylase-positives cells

New broad-spectrum resistance to septoria tritici blotch derived from synthetic hexaploid wheat

Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola, is one of the most devastating foliar diseases of wheat. We screened five synthetic hexaploid wheats (SHs), 13 wheat varieties that represent the differential set of cultivars and two susceptible checks with a global set of 20 isolates and discovered exceptionally broad STB resistance in SHs. Subsequent development and analyses of recombinant inbred lines (RILs) from a cross between the SH M3 and the highly susceptible bread wheat cv. Kulm revealed two novel resistance loci on chromosomes 3D and 5A. The 3D resistance was expressed in the seedling and adult plant stages, and it controlled necrosis (N) and pycnidia (P) development as well as the latency periods of these parameters. This locus, which is closely linked to the microsatellite marker Xgwm494, was tentatively designated Stb16q and explained from 41 to 71% of the phenotypic variation at seedling stage and 28–31% in mature plants. The resistance locus on chromosome 5A was specifically expressed in the adult plant stage, associated with SSR marker Xhbg247, explained 12–32% of the variation in disease, was designated Stb17, and is the first unambiguously identified and named QTL for adult plant resistance to M. graminicola. Our results confirm that common wheat progenitors might be a rich source of new Stb resistance genes/QTLs that can be deployed in commercial breeding programs

Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper

<p>Abstract</p> <p>Background</p> <p>Bacterial spot of tomato and pepper is caused by four <it>Xanthomonas </it>species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, <it>Xanthomonas euvesicatoria </it>(<it>Xcv</it>) has been previously reported. To determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing host ranges, draft genomic sequences of members of the other three species were determined and compared to strain 85-10.</p> <p>Results</p> <p>We sequenced the genomes of <it>X. vesicatoria </it>(<it>Xv</it>) strain 1111 (ATCC 35937), <it>X. perforans </it>(<it>Xp</it>) strain 91-118 and <it>X. gardneri </it>(<it>Xg</it>) strain 101 (ATCC 19865). The genomes were compared with each other and with the previously sequenced <it>Xcv </it>strain 85-10. In addition, the molecular features were predicted that may be required for pathogenicity including the type III secretion apparatus, type III effectors, other secretion systems, quorum sensing systems, adhesins, extracellular polysaccharide, and lipopolysaccharide determinants. Several novel type III effectors from <it>Xg </it>strain 101 and <it>Xv </it>strain 1111 genomes were computationally identified and their translocation was validated using a reporter gene assay. A homolog to Ax21, the elicitor of XA21-mediated resistance in rice, and a functional Ax21 sulfation system were identified in <it>Xcv</it>. Genes encoding proteins with functions mediated by type II and type IV secretion systems have also been compared, including enzymes involved in cell wall deconstruction, as contributors to pathogenicity.</p> <p>Conclusions</p> <p>Comparative genomic analyses revealed considerable diversity among bacterial spot pathogens, providing new insights into differences and similarities that may explain the diverse nature of these strains. Genes specific to pepper pathogens, such as the O-antigen of the lipopolysaccharide cluster, and genes unique to individual strains, such as novel type III effectors and bacteriocin genes, have been identified providing new clues for our understanding of pathogen virulence, aggressiveness, and host preference. These analyses will aid in efforts towards breeding for broad and durable resistance in economically important tomato and pepper cultivars.</p

Etude de stabilité d'un solide sous frottement de glissement par optimisation de la surface de contact

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Stabilisation d'un solide sous frottement de glissement par optimisation de la surface de contact

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Wheat Mds-1 encodes a heat-shock protein and governs susceptibility towards the Hessian fly gall midge

Citation: Liu, X., . . . & Chen, M. (2013). Wheat Mds-1 encodes a heat-shock protein and governs susceptibility towards the Hessian fly gall midge. Nature Communication, 4(1), 2070. https://doi.org/10.1038/ncomms3070Gall midges induce formation of host nutritive cells and alter plant metabolism to utilize host resources. Here we show that the gene Mayetiola destructor susceptibility-1 (Mds-1) on wheat chromosome 3AS encodes a small heat-shock protein and is a major susceptibility gene for infestation of wheat by the gall midge M. destructor, commonly known as the Hessian fly. Transcription of Mds-1 and its homoeologs increases upon insect infestation. Ectopic expression of Mds-1 or induction by heat shock suppresses resistance of wheat mediated by the resistance gene H13 to Hessian fly. Silencing of Mds-1 by RNA interference confers immunity to all Hessian fly biotypes on normally susceptible wheat genotypes. Mds-1-silenced plants also show reduced lesion formation due to infection by the powdery mildew fungus Blumeria graminis f. sp. tritici. Modification of susceptibility genes may provide broad and durable sources of resistance to Hessian fly, B. graminis f. sp. tritici, and other pests