71 research outputs found

    A highly osmotolerant rhizobial strain confers a better tolerance of nitrogen fixation and enhances protective activities to nodules of Phaseolus vulgaris under drought stress

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    The effect of water deficiency on nodules of common bean (Phaseolus vulgaris) inoculated with three rhizobial strains differing in their osmotolerance, was investigated in two different experiments on sterile sand. In the first experiment, the control plants were maintained at 90% field capacity (FC) and water-deficient plants were grown at 35% FC. The nitrogen fixation and growth parameters drastically decreased under water deficiency, however the three rhizobial strains, Rhizobium etli A32 (sensitive), Rhizobium tropici CIAT899 (tolerant), and Ensifer meliloti 4H41 (highly tolerant), showed different symbiotic performances. E. meliloti 4H41 allowed the best acetylene reduction activity (ARA) and biomass production and the highest number of large-sized nodules, while no significant effect was observed on lipid peroxidation, protein and legheamoglobin contents. The effect on antioxidant activities was the lowest. In the second experiment, plants were maintained at 90% FC during 45 days and then watering was stopped. The results showed that, the response to water deficit was quite similar for the three analyzed symbioses until 35% FC, but below this value of FC, symbiosis involving strain E. meliloti 4H41 was the most tolerant. This tolerance was accompanied, by in both experiments, by a stability of metabolic indices and protective antioxidant activities. These results suggest that, the relative tolerance of the nodules induced by strain 4H41 could be due to a constructive adaptation involving specific cortex structure and stress-adapted metabolic activities acquired during nodule formation and growth, rather than to a timely inducible response due to the stimulation of antioxidant enzymes. This suggestion should be confirmed through microscopic structure analysis and supplemental key enzymes in nodule metabolism such as sucrose synthase and malate dehydrogenase.Key words: Antioxidant activities, in pots experiment, leghemoglobin content, nodule, rhizobia, osmotolerance, symbiotic efficiency, water deficiency

    A bovine lymphosarcoma cell line infected with theileria annulata exhibits an irreversible reconfiguration of host cell gene expression

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    Theileria annulata, an intracellular parasite of bovine lymphoid cells, induces substantial phenotypic alterations to its host cell including continuous proliferation, cytoskeletal changes and resistance to apoptosis. While parasite induced modulation of host cell signal transduction pathways and NFÎșB activation are established, there remains considerable speculation on the complexities of the parasite directed control mechanisms that govern these radical changes to the host cell. Our objectives in this study were to provide a comprehensive analysis of the global changes to host cell gene expression with emphasis on those that result from direct intervention by the parasite. By using comparative microarray analysis of an uninfected bovine cell line and its Theileria infected counterpart, in conjunction with use of the specific parasitacidal agent, buparvaquone, we have identified a large number of host cell gene expression changes that result from parasite infection. Our results indicate that the viable parasite can irreversibly modify the transformed phenotype of a bovine cell line. Fifty percent of genes with altered expression failed to show a reversible response to parasite death, a possible contributing factor to initiation of host cell apoptosis. The genes that did show an early predicted response to loss of parasite viability highlighted a sub-group of genes that are likely to be under direct control by parasite infection. Network and pathway analysis demonstrated that this sub-group is significantly enriched for genes involved in regulation of chromatin modification and gene expression. The results provide evidence that the Theileria parasite has the regulatory capacity to generate widespread change to host cell gene expression in a complex and largely irreversible manner

    Identification of candidate transmission-blocking antigen genes in Theileria annulata and related vector-borne apicomplexan parasites

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    Background: Vector-borne apicomplexan parasites are a major cause of mortality and morbidity to humans and livestock globally. The most important disease syndromes caused by these parasites are malaria, babesiosis and theileriosis. Strategies for control often target parasite stages in the mammalian host that cause disease, but this can result in reservoir infections that promote pathogen transmission and generate economic loss. Optimal control strategies should protect against clinical disease, block transmission and be applicable across related genera of parasites. We have used bioinformatics and transcriptomics to screen for transmission-blocking candidate antigens in the tick-borne apicomplexan parasite, Theileria annulata. Results: A number of candidate antigen genes were identified which encoded amino acid domains that are conserved across vector-borne Apicomplexa (Babesia, Plasmodium and Theileria), including the Pfs48/45 6-cys domain and a novel cysteine-rich domain. Expression profiling confirmed that selected candidate genes are expressed by life cycle stages within infected ticks. Additionally, putative B cell epitopes were identified in the T. annulata gene sequences encoding the 6-cys and cysteine rich domains, in a gene encoding a putative papain-family cysteine peptidase, with similarity to the Plasmodium SERA family, and the gene encoding the T. annulata major merozoite/piroplasm surface antigen, Tams1. Conclusions: Candidate genes were identified that encode proteins with similarity to known transmission blocking candidates in related parasites, while one is a novel candidate conserved across vector-borne apicomplexans and has a potential role in the sexual phase of the life cycle. The results indicate that a ‘One Health’ approach could be utilised to develop a transmission-blocking strategy effective against vector-borne apicomplexan parasites of animals and humans

    Cloning retinoid and peroxisome proliferator-activated nuclear receptors of the Pacific oyster and in silico binding to environmental chemicals

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    This is the final version of the article. Available from Public Library of Science via the DOI in this record.Disruption of nuclear receptors, a transcription factor superfamily regulating gene expression in animals, is one proposed mechanism through which pollution causes effects in aquatic invertebrates. Environmental pollutants have the ability to interfere with the receptor's functions through direct binding and inducing incorrect signals. Limited knowledge of invertebrate endocrinology and molecular regulatory mechanisms, however, impede the understanding of endocrine disruptive effects in many aquatic invertebrate species. Here, we isolated three nuclear receptors of the Pacific oyster, Crassostrea gigas: two isoforms of the retinoid X receptor, CgRXR-1 and CgRXR-2, a retinoic acid receptor ortholog CgRAR, and a peroxisome proliferator-activated receptor ortholog CgPPAR. Computer modelling of the receptors based on 3D crystal structures of human proteins was used to predict each receptor's ability to bind to different ligands in silico. CgRXR showed high potential to bind and be activated by 9-cis retinoic acid and the organotin tributyltin (TBT). Computer modelling of CgRAR revealed six residues in the ligand binding domain, which prevent the successful interaction with natural and synthetic retinoid ligands. This supports an existing theory of loss of retinoid binding in molluscan RARs. Modelling of CgPPAR was less reliable due to high discrepancies in sequence to its human ortholog. Yet, there are suggestions of binding to TBT, but not to rosiglitazone. The effect of potential receptor ligands on early oyster development was assessed after 24h of chemical exposure. TBT oxide (0.2ÎŒg/l), all-trans retinoic acid (ATRA) (0.06 mg/L) and perfluorooctanoic acid (20 mg/L) showed high effects on development (>74% abnormal developed D-shelled larvae), while rosiglitazone (40 mg/L) showed no effect. The results are discussed in relation to a putative direct (TBT) disruption effect on nuclear receptors. The inability of direct binding of ATRA to CgRAR suggests either a disruptive effect through a pathway excluding nuclear receptors or an indirect interaction. Our findings provide valuable information on potential mechanisms of molluscan nuclear receptors and the effects of environmental pollution on aquatic invertebrates.The study was funded by the Centre for Environment, Fisheries and Aquaculture Science (Cefas; https://www.cefas.co.uk) and by the University of Exeter (http://www.exeter.ac.uk)

    Plant growth promoting rhizobia: challenges and opportunities

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    Exploring the utility of motion analysis in osteopathic clinical trials; a school-based pilot study on jaw and cervical range of motion

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    International audienceIntroduction: This study explores the value of using motion analysis to evaluate cervical and jaw ROM on students with or without bruxism when comparing Osteopathic Manipulative Treatment (OMT) to sham in school settings. Methods: A feasibility study was run with 48 volunteer students from an osteopathic educational institution. Random sequence for allocation was generated using a 1:1 ratio and block size of four to either OMT or sham treatment (control group). The chosen motion outcomes of interest were the lateral jaw range of motion, jaw opening, cervical rotation and side-bending. ROM was measured averaging over three repeated movements at baseline, immediately after the 1st treatment, one week before the 2nd treatment, and immediately after the second treatment using video-based analysis with 15 body landmarks. Results: Repeated measures of joint motion at baseline showed high levels of reliability (ICC ranging from 0.953 to 0.985). Motion analysis detected clinically important differences between OMT and sham one-week posttreatment for jaw lateral ROM (3.3 degrees; p = 0.018) and cervical rotation ROM (12.0 degrees; p = 0.003) in participants with bruxism but not in those without. Magnitude of differences were increased for all parameters following the second treatment (lateral jaw movement; 4.8 degrees, p = 0.005; jaw opening; 5.5 degrees, p = 0.002; cervical side-bending; 9.2 degrees, p = 0.023; cervical rotation; 18.2 degrees, p < 0.001). Conclusion: Motion analysis is capable of detecting the effects of OMT on cervical and jaw ROM in students with bruxism but not without. Finally, the study showed the feasibility of introducing usual standards for clinical trials and sham treatment in an educational setting with students

    Monitoring the volatile compounds status of whole seeds and flours of legume cultivars

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    The volatile compounds of twelve legume cultivars were evaluated by headspace-solid phase micro-extraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC-MS) from both whole seeds and their flours. The total identification percentages of the extracted volatiles were ranged between 94.2% and 99.7%. The number of aroma compounds detected was 104. Among them, 60 compounds were determined in the emission of whole legume seeds and 69 from legume flours. The volatiles were classified into seven chemical classes, i.e. monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, phenylpropanoids, apocarotenes, nitrogen/sulfur derivatives, and non-terpene derivatives. Aldehydes were considered one of the most abundant constituents in non-terpene derivatives, followed by esters, alkanes, alcohols, ketones, lactones, phenols, phenones, alkenes, and hydrocarbons. A wide difference in term of volatiles was observed between whole and crushed seeds. Multivariate data analysis (PCA) was assessed to compare among legume cultivars, which leads to the identification of relevant constituents to specific cultivar. Overall, this is the first time a multivariate analysis was used to characterize the volatile profiles of twelve legume cultivars with their flours. This study can provide useful information on the conception of legume–based ingredients combined with specific volatile characteristics in order to reduce unwanted odors and definitely for pertinent breeding programs

    Pain knowledge and fear-avoidance beliefs of French osteopathy students and educators towards chronic low back pain: An osteopathic educational institution-based cross-sectional survey

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    International audienceBackground: Practitioners’ fear-avoidance beliefs can influence positively or negatively therapeutic outcomes in their patients. This study reports pain knowledge and fear-avoidance beliefs of French osteopathy students and educators towards the management of chronic low back pain (cLBP). Methods: An online cross-sectional survey was proposed to educators and students. It included sociodemographic characteristics and two questionnaires: the FABQ-HC to assess beliefs on the effects of physical and work activities for people with cLBP, and the NPQ to assess participants' knowledge of pain. Results: Participants (N = 172) had mean FABQ-HC subscale scores of 11.02 ± 4.44 (Physical activity) and 24.37 ± 11.78 (Work). The mean NPQ total score was 11.90 ± 2.05. There were no significant score differences between students and educators (p > 0.05). Results showed that Year 4 students (N = 65) had a significantly better score (p < 0.05) at the FABQ-HC Physical Activity than Year 5 students (N = 71). Educators (N = 36) having less than 10 years of practice in osteopathy had better scores than other educators (p < 0.01) at the FABQ-HC Work. Educators and students in the study show similar scores to other French HCPs and international osteopaths on the FABQ-HC Physical activity. In contrast, they scored lower on the FABQ-HC Work. Conclusions: The main finding was that educators and students belonging to the same OEI have no significantly different beliefs about cLBP and no significantly differing knowledge of pain. There is potential to improve pain education especially concerning the beliefs around cLBP concerning work activity. © 2021 Elsevier Lt

    Physiological and biochemicals changes modulated by seeds’ priming of lentil (Lens culinaris L.) under salt stress at germination stage

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    Seed priming is one of the potential physiological approaches to enhance the seed germination under the salinity stress. The present study examined the role of two seed priming molecules: salicylic acid (SA) and hydrogen peroxide (H2O2), in enhancing the salt tolerance of lentil seeds at germination stage. Salinity stress caused significant decrease in germination percentage and primary root elongation. This decrease was associated with significant increase in lipid peroxidation and total lipid (TL) contents in embryonic axis. The catalase (CAT), guaiacol peroxydase (GPOX) and superoxide dismutase (SOD) activities remained unchanged or decreased significantly under the influence of salt stress, in both embryonic axis and cotyledons. Starch mobilization was not affected by the salt stress. The two priming treatments effectively alleviated the negative effects of salinity stress. SA and H2O2 applications after dose optimization resulted in a significant enhancement of germination percentage and primary root elongation. No significant changes in starch, soluble sugars contents and SOD activity were detected following SA and H2O2 treatments. Seed priming treatments triggered the activities of GPOX and CAT and caused the reduction in lipid peroxidation, especially in embryonic axis. TL content and especially the fatty acid C18:3 increased after SA applications. Better performance under salt stress of primed lentil seeds was associated with lower lipid peroxidation, and activation of enzymatic antioxidative defense system. Obtained results confirm the potential for using SA and H2O2 to improve germination and plant growth under salt stress conditions

    Impact of different types of revision materials on the learning of musculoskeletal techniques

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    Background: This study aimed to measure the impact of different revision materials developed for osteopathy students, by studying their results, their perceptions and their behaviour when revising for exams. Methods: A cohort of 68 second-year osteopathic students was allocated to three groups (pseudo-randomisation), each group being separately taught the same practical course, but provided with different types of revision materials (video, digital data sheet or no material). They were then assessed by an external examiner. Outcome measures were grades, time spent revising on the platform and student material perceptions collected via a practical assessment, by monitoring student visits on an education platform (TactilĂ©oÂź) and a questionnaire. Results: The results showed that the mean exam grades for the Video group were 14 higher than those of the No Materials group (p = 0.04, d = 0.94) and 29 higher than the Digital Data Sheet group (p < 0.01, d = 1.36). In addition, an interesting result was that students from the Video group spent more time using the revision materials (+29), consulted them more often (+25) and repeated their techniques more often than students in the Digital Data Sheet group (+14). Conclusions: The use of video revision material improved participants’ results while exerting a positive influence on their behaviour when revising but did not prevent surface learning. A structured teaching and learning approach will therefore need to be implemented if learners are to get all the benefits of video materials while being more engaged on a personal level. © 2020 Elsevier Lt
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