52 research outputs found
Nematode and Arthropod Genomes Provide New Insights into the Evolution of Class 2 B1 GPCRs
Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors
(GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and
Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the
evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod
genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and
designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and
arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of
the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a
conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and
Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in
representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in
protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of
nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan
radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication
and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.This work was supported by the Portuguese Foundation for Science and Technology (FCT) project PTDC/BIA-BCM/114395/2009, by the European
Regional Development Fund through COMPETE and FCT under the project ‘‘PEst-C/MAR/LA0015/2011.’’ RCF is in receipt of an FCT grant (SFRH/BPD/89811/2012)
and JCRC is supported by auxiliary research contract FCT Pluriannual funds attributed to CCMAR. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript
The Inhibitory Effect of Salmon Calcitonin on Tri-Iodothyronine Induction of Early Hypertrophy in Articular Cartilage
Salmon calcitonin has chondroprotective effect both in vitro and in vivo, and is therefore being tested as a candidate drug for cartilage degenerative diseases. Recent studies have indicated that different chondrocyte phenotypes may express the calcitonin receptor (CTR) differentially. We tested for the presence of the CTR in chondrocytes from tri-iodothyronin (T3)-induced bovine articular cartilage explants. Moreover, investigated the effects of human and salmon calcitonin on the explants.Early chondrocyte hypertrophy was induced in bovine articular cartilage explants by stimulation over four days with 20 ng/mL T3. The degree of hypertrophy was investigated by molecular markers of hypertrophy (ALP, IHH, COLX and MMP13), by biochemical markers of cartilage turnover (C2M, P2NP and AGNxII) and histology. The expression of the CTR was detected by qPCR and immunohistochemistry. T3-induced explants were treated with salmon or human calcitonin. Calcitonin down-stream signaling was measured by levels of cAMP, and by the molecular markers.Compared with untreated control explants, T3 induction increased expression of the hypertrophic markers (p<0.05), of cartilage turnover (p<0.05), and of CTR (p<0.01). Salmon, but not human, calcitonin induced cAMP release (p<0.001). Salmon calcitonin also inhibited expression of markers of hypertrophy and cartilage turnover (p<0.05).T3 induced early hypertrophy of chondrocytes, which showed an elevated expression of the CTR and was thus a target for salmon calcitonin. Molecular marker levels indicated salmon, but not human, calcitonin protected the cartilage from hypertrophy. These results confirm that salmon calcitonin is able to modulate the CTR and thus have chondroprotective effects
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Field aging of transparent polyethylene mulches. II: Influence on the effectiveness of soil heating
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Intensified soil solarization with closed greenhouses: Numerical and experimental studies
Soil solarization (heating by mulching a wet soil with transparent polyethylene sheets) for controlling soil-borne pests, has been used in regions with high temperatures and intense solar radiation. In cooler periods or regions, however, this method is not effective in the open field, but can be envisaged in closed greenhouses. In the present study, we developed a numerical one-dimensional model to predict the soil temperature regime in closed non-mulched and mulched greenhouses under various meteorological conditions. The model consists of six layers: cover, mulch, soil and three air layers (external, enclosed between soil and mulch, and enclosed between mulch and cover). Soil hydraulic and thermal characteristics, greenhouse cover and mulch photometric properties, and diurnal cycles of the environmental conditions are required for the simulations. The model was experimentally verified and applied to glass- and polyethylene-covered greenhouses, examining the influence of greenhouse covering material on heating of the mulched soil. Mulching the soil inside closed glasshouses increased the effectiveness of solarization over mulched soil in the open field or in closed polyethylene greenhouses
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The effect of reirrigation on the thermal regime of polyethylene-mulched soils: experimental and numerical studies
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