179 research outputs found

    Regulatory nodD1 and nodD2 genes of Rhizobium tropici strain CIAT 899 and their roles in the early stages of molecular signaling and host-legume nodulation.

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    Nodulation and symbiotic nitrogen fixation are mediated by several genes, both of the host legume and of the bacterium. The rhizobial regulatory nodD gene plays a critical role, orchestrating the transcription of the other nodulation genes. Rhizobium tropici strain CIAT 899 is an effective symbiont of several legumes?with an emphasis on common bean (Phaseolus vulgaris)?and is unusual in carrying multiple copies of nodD, the roles of which remain to be elucidated. Results: Phenotypes, Nod factors and gene expression of nodD1 and nodD2 mutants of CIAT 899 were compared with those of the wild type strain, both in the presence and in the absence of the nod-gene-inducing molecules apigenin and salt (NaCl). Differences between the wild type and mutants were observed in swimming motility and IAA (indole acetic acid) synthesis. In the presence of both apigenin and salt, large numbers of Nod factors were detected in CIAT 899, with fewer detected in the mutants. nodC expression was lower in both mutants; differences in nodD1 and nodD2 expression were observed between the wild type and the mutants, with variation according to the inducing molecule, and with a major role of apigenin with nodD1 and of salt with nodD2. In the nodD1 mutant, nodulation was markedly reduced in common bean and abolished in leucaena (Leucaena leucocephala) and siratro (Macroptilium atropurpureum), whereas a mutation in nodD2 reduced nodulation in common bean, but not in the other two legumes. Conclusion: Our proposed model considers that full nodulation of common bean by R. tropici requires both nodD1 and nodD2, whereas, in other legume species that might represent the original host, nodD1 plays the major role. In general, nodD2 is an activator of nod-gene transcription, but, in specific conditions, it can slightly repress nodD1. nodD1 and nodD2 play other roles beyond nodulation, such as swimming motility and IAA synthesis

    NrcR, a new transcriptional regulator of Rhizobium tropici CIAT 899 involved in the Legume root-nodule symbiosis.

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    The establishment of nitrogen-fixing rhizobium-legume symbioses requires a highly complex cascade of events. In this molecular dialogue the bacterial NodD transcriptional regulators in conjunction with plant inducers, mostly flavonoids, are responsible for the biosynthesis and secretion of Nod factors which are key molecules for successful nodulation. Other transcriptional regulators related to the symbiotic process have been identified in rhizobial genomes, including negative regulators such as NolR. Rhizobium tropici CIAT 899 is an important symbiont of common bean (Phaseolus vulgaris L.), and its genome encompasses intriguing features such as five copies of nodD genes, as well as other possible transcriptional regulators including the NolR protein. Here we describe and characterize a new regulatory gene located in the non-symbiotic plasmid pRtrCIAT899c, that shows homology (46% identity) with the nolR gene located in the chromosome of CIAT 899. The mutation of this gene, named nrcR (nolR-like plasmid c Regulator), enhanced motility and exopolysaccharide production in comparison to the wild-type strain. Interestingly, the number and decoration of Nod Factors produced by this mutant were higher than those detected in the wildtype strain, especially under salinity stress. The nrcR mutant showed delayed nodulation and reduced competitiveness with P. vulgaris, and reduction in nodule number and shoot dry weight in both P. vulgaris and Leucaena leucocephala. Moreover, the mutant exhibited reduced capacity to induce the nodC gene in comparison to the wild-type CIAT 899. The finding of a new nod-gene regulator located in a non-symbiotic plasmid may reveal the existence of even more complex mechanisms of regulation of nodulation genes in R. tropici CIAT 899 that may be applicable to other rhizobial species

    Building on-line materials for teaching parasitology to health sciences’ students: initial impressions.

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    Background: It is widely recognised that the use of web-based teaching resources is an increasingly important method for delivering education, and it will be particularly important in the near future due to the progressively increasing number of health science students and the current number of academics in the “European Higher Education Area”. The study of parasitology and infectious diseases is essential to build professionals in the health sector with the key knowledge and skills to face global public health threats such as food-, water- or vector-borne infectious diseases outbreaks. However, the current time dedicated to the teaching of this discipline in all health sciences degrees at De Montfort University (DMU, Leicester, UK) is very little or non-existent depending on the degree/master. Methods: An innovative teaching group at DMU is trying to fill this gap in the currently available teaching offer in line with new trends in global health education, the large number of students enrolled in any health degree and the increasing number of students that would like to study this discipline (but due to different commitments do not have enough time or resources to study on a full time basis). Thus, an innovative teaching group from different EU Universities (DMU and the Spanish universities: University of San Pablo CEU, University of Alcalá, and University Miguel Hernández de Elche) and clinicians (University Hospitals of Leicester, UK) have started to design, create and develop a complete on-line package in Parasitology for undergraduate and postgraduate students that study health sciences. Results: The e-Parasitology package will be accessible through the DMU website (http://parasitology.dmu.ac.uk) in 2017 and will be focused on infection, prevention and treatment of major and emerging parasitological diseases. Conclusions: This teaching resource will aid our undergraduate and postgraduate students to gain a significant knowledge in parasitology by promoting self-learning and internationalization. This poster will explore one of the first mini-modules developed so far related with Toxocara, a helminthiasis with prevalence rates that can reach as high as 40% or more in parts of the world, and the challenges for its development

    The Harvey–Bradshaw Index adapted to a mobile application compared with In-clinic assessment: the MediCrohn Study

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    [Abstract] Objectives: Mobile apps are useful tools in e-health and self-management strategies in disease monitoring. We evaluated the Harvey–Bradshaw index (HBI) mobile app self-administered by the patient to see if its results agreed with HBI in-clinic assessed by a physician. Methods: Patients were enrolled in a 4-month prospective study with clinical assessments at months 1 and 4. Patients completed mobile app HBI and within 48 h, HBI was performed by a physician (gold standard). HBI scores characterized Crohn's disease (CD) as remission <5 or active ≥5. We determined agreement per item and total HBI score and intraclass correlation coefficients (ICCs). Bland–Altman plot was performed. HBI changes in disease activity from month 1 to month 4 were determined. Results: A total of 219 patients were enrolled. All scheduled assessments (385 pairs of the HBI questionnaire) showed a high percentage of agreement for remission/activity (92.4%, κ = 0.796), positive predictive value (PPV) for remission of 98.2%, and negative predictive value of 76.7%. High agreement was also found at month 1 (93.15%, κ = 0.82) and month 4 (91.5%, κ = 0.75). Bland–Altman plot was more uniform when the HBI mean values were <5 (remission). ICC values were 0.82, 0.897, and 0.879 in all scheduled assessments, 1 and 4 months, respectively. Conclusions: We found a high percentage of agreement between patients' self-administered mobile app HBI and in-clinic physician assessment to detect CD activity with a remarkably high PPV for remission. The mobile app HBI might allow a strict control of inflammation by remote monitoring and flexible follow-up of CD patients. Reduction of sanitary costs could be possible

    Developing a novel resource for teaching and learning parasitology: DMU e-Parasitology.

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    Background: The study of parasitology has become essential to develop future health care professionals with skills to respond to public health threats such as the recent outbreak of Cryptosporidium in the UK. To facilitate the teaching of parasitology, which is negligible across the different undergraduate and taught masters degrees at De Montfort University (DMU, UK), a group from different EU Universities [DMU and the Spanish universities: University of San Pablo CEU (USP-CEU) and University Miguel Hernández] and clinicians are developing an on-line package for teaching and learning parasitology named DMU e-Parasitology. The development of this teaching resource will cover a gap in the traditional teaching and learning methods that are currently used and provided in the participating universities. Materials/methods: The DMU e-Parasitology resource is being created for undergraduate and postgraduate human health science students, with corresponding degrees of difficulty on the DMU website (http://parasitology.dmu.ac.uk/). To develop the theoretical section, a preliminary unit about the helminth Toxocara was initially developed to be used as a model for this section: http://parasitology.dmu.ac.uk/learn/modules/toxocara/story.html. Volunteers that studied Parasitology during the first term in 2016/17 [n=27; 6 European Credit Transfer and Accumulation System credits (ECTS); 3rd year module] from the bilingual Pharmacy and Biotechnology degree at USP-CEU provided comprehensive feedback for this preliminary unit at the beginning of the second term. The module was tested with these students because of their knowledge of parasitology. Results: Students described the initial unit as interactive and presenting the appropriate content and resources to study the parasitic disease addressed (toxocariasis). Limitations were the poor navigability in the formative exercise section and the excessive information provided in some slides that could hinder their understanding. Conclusions: The team has addressed these limitations and is using this unit as a model to build the DMU e-Parasitology, which will be accessible through the website (http://parasitology.dmu.ac.uk) in 2018. We consider that this teaching and learning resource will overcome barriers of time, space, equipment and resource. Finally, this resource could facilitate the introduction of parasitology in any health science programme with limited time for teaching this subject in their curriculums

    Correlation Between Anti-TNF Serum Levels and Endoscopic Inflammation in Inflammatory Bowel Disease Patients

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    Objectives: (a) To evaluate the diagnostic accuracy of anti-TNF trough levels to predict mucosal healing in inflammatory bowel disease (IBD); (b) to determine the best cut-off point to predict mucosal healing in IBD patients treated with anti-TNF. Methods: This is a multicenter, prospective study. IBD patients under anti-TNF treatment for at least 6 months that had to undergo an endoscopy were included. Mucosal healing was defined as: Simple endoscopic score for Crohn’s Disease < 3 for Crohn’s disease (CD), Rutgeerts score < i2 for CD in postoperative setting, or Mayo endoscopic score = 1 for ulcerative colitis (UC). Anti-TNF concentrations were measured using SMART ELISAs at trough. Results: A total of 182 patients were included. Anti-TNF trough levels were significantly higher among patients that had mucosal healing than among those who did not. The area under the curve of infliximab for mucosal healing was 0.63 (best cutoff value 3.4 µg/mL), and for adalimumab 0.60 (best cutoff value 7.2 µg/mL). In the multivariate analysis, having anti-TNF drug levels above the cutoff values [odds ratio (OR) 3.1]) and having UC instead of CD (OR 4) were associated with a higher probability of having mucosal healing. Additionally, the need for an escalated dosage (OR 0.2) and current smoking habit (OR 0.2) were also associated with a lower probability of mucosal healing. Conclusions: There was an association between anti-TNF trough levels and mucosal healing in IBD patients; however, the accuracy of the determination of infliximab and adalimumab concentrations able to predict mucosal healing was suboptimal

    Amyloid β-but not Tau-induced neurotoxicity is suppressed by Manuka honey via HSP-16.2 and SKN-1/Nrf2 pathways in an in vivo model of Alzheimer’s disease

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    Alzheimer’s is a chronic degenerative disease of the central nervous system considered the leading cause of dementia in the world. It is characterized by two etiopathological events related to oxidative stress: the aggregation of β-amyloid peptide and the formation of neurofibrillary tangles of hyperphosphorylated Tau protein in the brain. The incidence of this disease increases with age and has been associated with inadequate lifestyles. Some natural compounds have been shown to improve the hallmarks of the disease. However, despite its potential, there is no scientific evidence about Manuka honey (MH) in this regard. In the present work we evaluated the effect of MH on the toxicity induced by Aβ aggregation and Tau in a Caenorhabditis elegans model. Our results demonstrated that MH was able to improve indicators of oxidative stress and delayed Aβ-induced paralysis in the AD model CL4176 through HSP-16.2 and SKN-1/ NRF2 pathways. Nevertheless, its sugar content impaired the indicators of locomotion (an indicator of tau neurotoxicity) in both the transgenic strain BR5706 and in the wild-type N2 worms.MCIN/AEI FPU2017/04358FSE "El FSE invierte en tu futuro" FPU2018/05301JdC-I post-doctoral contract - NextGenerationEU IJC2020-043910-IFEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento B-AGR-193-UGR1
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