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61.
62.
In Xenopus, the primary neurons form in three domains either side of the midline in the posterior neurectoderm. At the late neurula stage there are approximately 120 primary sensory neurons on each side of the embryo. Co-injecting synthetic mRNA encoding retinoic acid receptor alpha (NR1B1) and retinoid X receptor beta (NR2B2) results in an increase in the number of primary neurons and this is further enhanced by the addition of retinoic acid indicating that elevated retinoid signalling promotes an increase in the number of cells undergoing primary neurogenesis. However, primary neurogenesis remains confined to the three domains that normally give rise to primary neurons indicating that not all regions of the neurectoderm respond equivalently to elevated retinoid signalling. The inhibition of retinoid signalling with a dominant negative retinoid receptor or treatment with citral, an inhibitor of retinoid metabolism, inhibits the formation of primary neurons. However, the lateral extent of the neurectoderm does not differ following these experimental manipulations suggesting that changes in primary neuron cell number, in response to changes in retinoid signalling, cannot be accounted for by significant gains or losses of neurectoderm. In addition, two lines of evidence are presented to suggest that retinoid signalling affects primary neurogenesis by acting directly on the neurectoderm. First, animal caps neuralized by noggin undergo primary neurogenesis in response to retinoid signalling and second primary neurogenesis is elevated in neural conjugates in which the ectodermal, but not the mesodermal, component has been co-injected with RAR/RXR mRNA. 相似文献
63.
Goldstone AP Morgan I Mercer JG Morgan DG Moar KM Ghatei MA Bloom SR 《Biochemical and biophysical research communications》2000,269(2):331-335
Leptin, the adipocyte-derived plasma hormone, and CNS GLP-1 neurons reduce food intake and body weight. GLP-1 is produced in the CNS by post-translational processing of pre-proglucagon. ICV leptin administration prevented the reduction in hypothalamic GLP-1 peptide content seen in pair-fed food-restricted rats (P < 0.05). There was a significant overall positive correlation between pre-proglucagon mRNA expression in the NTS and hypothalamic GLP-1 peptide content (r = +0.34, P < 0.05). Intraperitoneal leptin administration also increased hypothalamic GLP-1 peptide in food-restricted mice (P < 0. 05). This supports the hypothesis that the anorectic actions of leptin are in part due to stimulation of GLP-1 neurons. Reduced CNS GLP-1 neuronal activity during food deprivation may act to stimulate feeding behaviour, and perhaps also inhibit hypothalamic LHRH neurons, as part of the neuroendocrine response to starvation. 相似文献
64.
Histocompatibility antigens were determined in 30 patients with temporal arteritis, 27 patients with polymyalgia rheumatica, and 216 normal blood donors. HLA-B8 was significantly more common in patients with polymyalgia rheumatica (59%) and temporal arteritis (50%) than in the controls (27%). The findings of HLA-A10 in 26% of the patients with polymyalgia rheumatica compared with only 10% of the controls may be associated with the suggested immunological pathogenesis of the condition. 相似文献
65.
Gao K Brandt I Goldstone JV Jönsson ME 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2011,154(1):42-55
Cytochrome P450 1 (CYP1) mRNA induction patterns in three-spined stickleback (Gasterosteus aculeatus) were explored for use in environmental monitoring of aryl hydrocarbon receptor (AHR) agonists. The cDNAs of stickleback CYP1A, CYP1B1, CYP1C1, and CYP1C2 were cloned and their basal and induced expression patterns were determined in the brain, gill, liver and kidney. Also, their induction time courses were compared after waterborne exposure to a transient (indigo) or a persistent (3,3',4,4',5-pentacholorbiphenyl PCB 126) AHR agonist. The cloned stickleback CYP1s exhibited a high amino acid sequence identity compared with their zebrafish orthologs and their constitutive tissue distribution patterns largely agreed with those reported in other species. PCB 126 (100 nM) induced different CYP1 expression patterns in the four tissues, suggesting tissue-specific regulation. Both indigo (1 nM) and PCB 126 (10 nM) induced a strong CYP1 expression in gills. However, while PCB 126 gave rise to a high and persistent induction in gills and liver, induction by indigo was transient in both organs. The number of putative dioxin response elements found in each CYP1 gene promoter roughly reflected the induction levels of the genes. The high responsiveness of CYP1A, CYP1B1, and CYP1C1 observed in several organs suggests that three-spined stickleback is suitable for monitoring of pollution with AHR agonists. 相似文献
66.
David R. Nelson Jared V. Goldstone John J. Stegeman 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2013,368(1612)
The neighbourhoods of cytochrome P450 (CYP) genes in deuterostome genomes, as well as those of the cnidarians Nematostella vectensis and Acropora digitifera and the placozoan Trichoplax adhaerens were examined to find clues concerning the evolution of CYP genes in animals. CYP genes created by the 2R whole genome duplications in chordates have been identified. Both microsynteny and macrosynteny were used to identify genes that coexisted near CYP genes in the animal ancestor. We show that all 11 CYP clans began in a common gene environment. The evidence implies the existence of a single locus, which we term the ‘cytochrome P450 genesis locus’, where one progenitor CYP gene duplicated to create a tandem set of genes that were precursors of the 11 animal CYP clans: CYP Clans 2, 3, 4, 7, 19, 20, 26, 46, 51, 74 and mitochondrial. These early CYP genes existed side by side before the origin of cnidarians, possibly with a few additional genes interspersed. The Hox gene cluster, WNT genes, an NK gene cluster and at least one ARF gene were close neighbours to this original CYP locus. According to this evolutionary scenario, the CYP74 clan originated from animals and not from land plants nor from a common ancestor of plants and animals. The CYP7 and CYP19 families that are chordate-specific belong to CYP clans that seem to have originated in the CYP genesis locus as well, even though this requires many gene losses to explain their current distribution. The approach to uncovering the CYP genesis locus overcomes confounding effects because of gene conversion, sequence divergence, gene birth and death, and opens the way to understanding the biodiversity of CYP genes, families and subfamilies, which in animals has been obscured by more than 600 Myr of evolution. 相似文献
67.
Parente TE Rebelo MF da-Silva ML Woodin BR Goldstone JV Bisch PM Paumgartten FJ Stegeman JJ 《Gene》2011,489(2):111-118
The Amazon catfish genus Pterygoplichthys (Loricariidae, Siluriformes) is closely related to the loricariid genus Hypostomus, in which at least two species lack detectable ethoxyresorufin-O-deethylase (EROD) activity, typically catalyzed by cytochrome P450 1 (CYP1) enzymes. Pterygoplichthys sp. liver microsomes also lacked EROD, as well as activity with other substituted resorufins, but aryl hydrocarbon receptor agonists induced hepatic CYP1A mRNA and protein suggesting structural/functional differences in Pterygoplichthys CYP1s from those in other vertebrates. Comparing the sequences of CYP1As of Pterygoplichthys sp. and of two phylogenetically related siluriform species that do catalyze EROD (Ancistrus sp., Loricariidae and Corydoras sp., Callichthyidae) showed that these three proteins share amino acids at 17 positions that are not shared by any fish in a set of 24 other species. Pterygoplichthys and Ancistrus (the loricariids) have an additional 22 amino acid substitutions in common that are not shared by Corydoras or by other fish species. Pterygoplichthys has six exclusive amino acid substitutions. Molecular docking and dynamics simulations indicate that Pterygoplichthys CYP1A has a weak affinity for ER, which binds infrequently in a productive orientation, and in a less stable conformation than in CYP1As of species that catalyze EROD. ER also binds with the carbonyl moiety proximal to the heme iron. Pterygoplichthys CYP1A has amino acid substitutions that reduce the frequency of correctly oriented ER in the AS preventing the detection of EROD activity. The results indicate that loricariid CYP1As may have a peculiar substrate selectivity that differs from CYP1As of most vertebrate. 相似文献
68.
Pauline?AaltenEmail author Inez?HGB?Ramakers Geert?Jan?Biessels Peter?Paul?de Deyn Huiberdina?L?Koek Marcel?GM?OldeRikkert Ania?M?Oleksik Edo?Richard Lieke?L?Smits John?C?van Swieten Laura?K?Teune Aad?van der Lugt Frederik?Barkhof Charlotte?E?Teunissen Nico?Rozendaal Frans?RJ?Verhey Wiesje?M?van der Flier 《BMC neurology》2014,14(1):254
69.
Abad P Gouzy J Aury JM Castagnone-Sereno P Danchin EG Deleury E Perfus-Barbeoch L Anthouard V Artiguenave F Blok VC Caillaud MC Coutinho PM Dasilva C De Luca F Deau F Esquibet M Flutre T Goldstone JV Hamamouch N Hewezi T Jaillon O Jubin C Leonetti P Magliano M Maier TR Markov GV McVeigh P Pesole G Poulain J Robinson-Rechavi M Sallet E Ségurens B Steinbach D Tytgat T Ugarte E van Ghelder C Veronico P Baum TJ Blaxter M Bleve-Zacheo T Davis EL Ewbank JJ Favery B Grenier E Henrissat B Jones JT 《Nature biotechnology》2008,26(8):909-915
Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the assembled sequence of this asexually reproducing nematode, totaling 86 Mb, exists in pairs of homologous but divergent segments. This suggests that ancient allelic regions in M. incognita are evolving toward effective haploidy, permitting new mechanisms of adaptation. The number and diversity of plant cell wall-degrading enzymes in M. incognita is unprecedented in any animal for which a genome sequence is available, and may derive from multiple horizontal gene transfers from bacterial sources. Our results provide insights into the adaptations required by metazoans to successfully parasitize immunocompetent plants, and open the way for discovering new antiparasitic strategies. 相似文献
70.
Masashi Kawamura Michael J. Paulsen Andrew B. Goldstone Yasuhiro Shudo Hanjay Wang Amanda N. Steele Lyndsay M. Stapleton Bryan B. Edwards Anahita Eskandari Vi N. Truong Kevin J. Jaatinen Arnar B. Ingason Shigeru Miyagawa Yoshiki Sawa Y. Joseph Woo 《Cardiovascular diabetology》2017,16(1):142