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Many studies show that a large percentage of students lack the digital competencies to solve information problems using the internet. To address this problem, researchers have developed models to structure the process. However, we maintain that it is first necessary to understand how students actually search for information online when solving an information problem and compare their behaviours with the available literature. To do this, we collected and analysed the data on a laboratory setting of 41 students while they solved 16 information problems using the internet and expressed aloud what they were thinking whilst solving them. We identified 21 categories of actions, grouped into 9 activity types associated with four information search processes, showing that some of the students' stereotyped search behaviours are in fact conscious decisions based on the requirements of the task and the answers found. The results also show that searching for information on the internet can not only vary depending on the task's requirements, but also on the number of iterations students need to perform to reach an answer. These findings provide some evidence that challenge the assumption that students simply lack the competencies to search for information on the internet; rather, it seems that they show an awareness of different strategies, which they decide to use based on the context and purpose of the task, making their search behaviour more elaborated and complex than is usually portrayed by researchers in the field. Based on this, implications and further research lines are also discussed.

Type II pneumocytes are the target of the SARS-CoV-2 virus, which alters their redox homeostasis to increase reactive oxygen species (ROS). Melatonin (MT) has antioxidant proprieties and protects mitochondrial function. In this study, we evaluated whether treatment with MT compensated for the redox homeostasis alteration in serum from COVID-19 patients. We determined oxidative stress (OS) markers such as carbonyls, glutathione (GSH), total antioxidant capacity (TAC), thiols, nitrites (NO2−), lipid peroxidation (LPO), and thiol groups in serum. We also studied the enzymatic activities of glutathione peroxidase (GPx), glutathione-S-transferase (GST), reductase (GR), thioredoxin reductase (TrxR), extracellular superoxide dismutase (ecSOD) and peroxidases. There were significant increases in LPO and carbonyl quantities (p ≤ 0.03) and decreases in TAC and the quantities of NO2−, thiols, and GSH (p < 0.001) in COVID-19 patients. The activities of the antioxidant enzymes such as ecSOD, TrxR, GPx, GST, GR, and peroxidases were decreased (p ≤ 0.04) after the MT treatment. The treatment with MT favored the activity of the antioxidant enzymes that contributed to an increase in TAC and restored the lost redox homeostasis. MT also modulated glucose homeostasis, functioning as a glycolytic agent, and inhibited the Warburg effect. Thus, MT restores the redox homeostasis that is altered in COVID-19 patients and can be used as adjuvant therapy in SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

In September 2022, symptoms of leaf anthracnose were observed on desert rose (Adenium obesum) plants distributed in parks and gardens in Culiacán, Sinaloa, Mexico. Two morphotypes of Colletotrichum isolates were obtained from symptomatic tissues. Based on morphological characterization in combination with multilocus phylogenetic analyses including data from internal transcribed spacer, actin, glyceraldehyde‐3‐phosphate dehydrogenase, and β‐tubulin, and pathogenicity tests, it was confirmed that C. siamense and C. truncatum are the causal agents of the disease. This is the first report of C. siamense and C. truncatum causing leaf anthracnose in desert rose worldwide. [ABSTRACT FROM AUTHOR]

Type IVc Pili (T4cP), also known as Tad or Flp pili, are long thin microbial filaments that are made up of small-sized pilins. These appendages serve different functions in bacteria, including attachment, biofilm formation, surface sensing, motility, and host colonization. Despite their relevant role in diverse microbial lifestyles, knowledge about T4cP in bacteria that establish symbiosis with legumes, collectively referred to as rhizobia, is still limited. Sinorhizobium meliloti contains two clusters of T4cP-related genes: flp-1 and flp-2, which are located on the chromosome and the pSymA megaplasmid, respectively. Bundle-forming pili associated with flp-1 are involved in the competitive nodulation of alfalfa plants, but the role of flp-2 remains elusive. In this work, we have performed a comprehensive bioinformatic analysis of T4cP genes in the highly competitive S. meliloti GR4 strain and investigated the role of its flp clusters in pilus biogenesis, motility, and in the interaction with alfalfa. Single and double flp-cluster mutants were constructed on the wild-type genetic background as well as in a flagellaless derivative strain. Our data demonstrate that both chromosomal and pSymA flp clusters are functional in pili biogenesis and contribute to surface translocation and nodule formation efficiency in GR4. In this strain, the presence of flp-1 in the absence of flp-2 reduces the competitiveness for nodule occupation. [ABSTRACT FROM AUTHOR]

BackgroundSwarming motility and biofilm formation are opposite, but related surface-associated behaviors that allow various pathogenic bacteria to colonize and invade their hosts. In Sinorhizobium meliloti, the alfalfa endosymbiont, these bacterial processes and their relevance for host plant colonization are largely unexplored. Our previous work demonstrated distinct swarming abilities in two S. meliloti strains (Rm1021 and GR4) and revealed that both environmental cues (iron concentration) and bacterial genes (fadD, rhb, rirA) play crucial roles in the control of surface motility in this rhizobial species. In the current study, we investigate whether these factors have an impact on the ability of S. meliloti to establish biofilms and to colonize host roots.ResultsWe found that strain GR4, which is less prone to translocate on solid surfaces than strain Rm1021, is more efficient in developing biofilms on glass and plant root surfaces. High iron conditions, known to prevent surface motility in a wild-type strain of S. meliloti, promote biofilm development in Rm1021 and GR4 strains by inducing the formation of more structured and thicker biofilms than those formed under low iron levels. Moreover, three different S. meliloti mutants (fadD, rhb, and rirA) that exhibit an altered surface translocation behavior compared with the wild-type strain, establish reduced biofilms on both glass and alfalfa root surfaces. Iron-rich conditions neither rescue the defect in biofilm formation shown by the rhb mutant, which is unable to produce the siderophore rhizobactin 1021 (Rhb1021), nor have any impact on biofilms formed by the iron-response regulator rirA mutant. On the other hand, S. meliloti FadD loss-of-function mutants do not establish normal biofilms irrespective of iron levels.ConclusionsOur studies show that siderophore Rhb1021 is not only required for surface translocation, but also for biofilm formation on glass and root surfaces by strain Rm1021. In addition, we present evidence for the existence of control mechanisms that inversely regulate swarming and biofilm formation in S. meliloti, and that contribute to efficient plant root colonization. One of these mechanisms involves iron levels and the iron global regulator RirA. The other mechanism involves the participation of the fatty acid metabolism-related enzyme FadD.

The use of alternative interventions, such as gluten-free and casein-free (GFCF) diets, is frequent due to limited therapies for Autism Spectrum Disorder (ASD). Our aims were to determine the influence of a GFCF diet on behavior disorders in children and adolescents diagnosed with ASD and the potential association with urinary beta-casomorphin concentrations. Thirty-seven patients were recruited for this crossover trial. Each patient consumed a normal diet (including gluten and casein) for 6 months and a GFCF diet for another 6 months. The order of the intervention (beginning with normal diet or with GFCF diet) was assigned randomly. Patients were evaluated at three time-points (at the beginning of the study, after normal diet and after GFCF diet). Questionnaires regarding behavior and autism and dietary adherence were completed and urinary beta-casomorphin concentrations were determined at each time-point. No significant behavioral changes and no association with urinary beta-casomorphin concentrations were found after GFCF diet. A 6-month GFCF diet do not induce significant changes in behavioral symptoms of autism and urinary beta-casomorphin concentrations. Further studies with a long follow-up period similar to ours and including placebo and blinding elements are needed to identify better those respondents to GFCF diets., Author(s): Pablo José González-Domenech [sup.1] [sup.2] , Francisco Díaz Atienza [sup.1] , Carlos García Pablos [sup.1] , María Luisa Fernández Soto [sup.3] , José María Martínez-Ortega [sup.2] , Luis Gutiérrez-Rojas [...]