The microbiologist’s guide to membrane potential dynamics

All cellular membranes have the functionality of generating and maintaining the gradients of electrical and electrochemical potentials. Such potentials were generally thought to be an essential but homeostatic contributor to complex bacterial behaviors. Recent studies have revised this view, and we now know that bacterial membrane potential is dynamic and plays signaling roles in cell–cell interaction, adaptation to antibiotics, and sensation of cellular conditions and environments. These discoveries argue that bacterial membrane potential dynamics deserve more attention. Here, we review the recent studies revealing the signaling roles of bacterial membrane potential dynamics. We also introduce basic biophysical theories of the membrane potential to the microbiology community and discuss the needs to revise these theories for applications in bacterial electrophysiology

Progresión o persistencia en las explicaciones de los alumnos. Un ejemplo en el área del enlace químico

La persistencia (también llamada estabilidad por algunos autores), entendida como la existencia prácticamente inalterada de las concepciones a lo largo de los años y a pesar de la instrucción escolar, es una característica que contrasta con los hallazgos de otras investigaciones que ponen de manifiesto que el conocimiento del alumno progresa con la edad. En este trabajo, se argumenta que la metodología de investigación es la clave para encontrar un resultado u otro. Las estrategias metodológicas que pueden ayudar a encontrar una u otra característica son a) la forma de categorizar las respuestas de los alumnos, b) el grado de dificultad de la pregunta realizada y c) el diseño del instrumento de recogida de datos. Para justificar la argumentación, se usan ejemplos extraídos de una investigación sobre el enlace químico

Progresión o persistencia en las explicaciones de los alumnos. Un ejemplo en el área del enlace químico

La persistencia (también llamada estabilidad por algunos autores), entendida como la existencia prácticamente inalterada de las concepciones a lo largo de los años y a pesar de la instrucción escolar, es una característica que contrasta con los hallazgos de otras investigaciones que ponen de manifiesto que el conocimiento del alumno progresa con la edad. En este trabajo, se argumenta que la metodología de investigación es la clave para encontrar un resultado u otro. Las estrategias metodológicas que pueden ayudar a encontrar una u otra característica son a) la forma de categorizar las respuestas de los alumnos, b) el grado de dificultad de la pregunta realizada y c) el diseño del instrumento de recogida de datos. Para justificar la argumentación, se usan ejemplos extraídos de una investigación sobre el enlace químico

Box H/ACA snoRNAs are preferred substrates for the trimethylguanosine synthase in the divergent unicellular eukaryote Trichomonas vaginalis.

The 2,2,7-trimethylguanosine caps of eukaryal snRNAs and snoRNA are formed by the enzyme Tgs1, which catalyzes sequential guanine-N2 methylations of m7G caps. Atypically, in the divergent unicellular eukaryote Trichomonas vaginalis, spliceosomal snRNAs lack a guanosine cap and the recombinant T. vaginalis trimethylguanosine synthase (TvTgs) produces only m2,7G in vitro. Here, we show by direct metabolic labeling that endogenous T. vaginalis RNAs contain m7G, m2,7G, and m2,2,7G caps. Immunodepletion of TvTgs from cell extracts and TvTgs add-back experiments demonstrate that TvTgs produces m2,7G and m2,2,7G caps. Expression of TvTgs in yeast tgs1D cells leads to the formation of m2,7G and m2,2,7G caps and complementation of the lethality of a tgs1D mud2D strain. Whereas TvTgs is present in the nucleus and cytosol of T. vaginalis cells, TMG-containing RNAs are localized primarily in the nucleolus. Molecular cloning of anti-TMG affinity-purified T. vaginalis RNAs identified 16 box H/ACA snoRNAs, which are implicated in guiding RNA pseudouridylation. The ensemble of new T. vaginalis H/ACA snoRNAs allowed us to predict and partially validate an extensive map of pseudouridines in T. vaginalis rRNA

Los planes de estudio en la formación del maestro en Educación Primaria en el espacio europeo de educación superior. Un estudio empírico para conocer de dónde venimos y adónde vamos

Ante los cambios estructurales y metodológicos que suponen las nuevas titulaciones del Grado de Magisterio surgidas en el marco del Espacio Europeo de Educación Superior (EEES), en este artículo establecemos la comparación de los contenidos formativos de los distintos planes de estudio desde que se constituyó la Escuela Universitaria de Formación del profesorado de EGB de Melilla hasta la propuesta del Libro Blanco de Magisterio (ANECA, 2005); y recogemos la valoración del futuro plan de estudio del Grado de Maestro de Educación Primaria por parte de los colectivos vinculados: profesores de la Facultad de Educación y Humanidades de Melilla, maestros en ejercicio y alumnos en el último año de sus estudios de Magisterio, al mismo tiempo que nos informan sobre sus necesidades formativas en las didácticas específi cas.Given the structural and methodological changes that suppose the new Degrees of Teacher’s Formation emerged in the European Higher Education Area (EHEA), in this article we compare the formative contents of the curricula since it was constituted the University School of Formation of Melilla until the proposal of White Book of Teaching in 2005. Also, we have investigated the valuation of the future curricula of formation of primary school teachers on the part of the following groups: teachers of the Faculty of Education and Humanities of Melilla, teachers of primary schools and pupils in the latter year of his studies, at the same time as they inform us about his specifi c formative needs.Facultad de Educación y Humanidades - Campus de Melilla (Universidad de Granada

Nucleotide analogs and molecular modeling studies reveal key interactions involved in substrate recognition by the yeast RNA triphosphatase

RNA triphosphatases (RTPases) are involved in the addition of the distinctive cap structure found at the 5′ ends of eukaryotic mRNAs. Fungi, protozoa and some DNA viruses possess an RTPase that belongs to the triphosphate tunnel metalloenzyme family of enzymes that can also hydrolyze nucleoside triphosphates. Previous crystallization studies revealed that the phosphohydrolase catalytic core is located in a hydrophilic tunnel composed of antiparallel β-strands. However, all past efforts to obtain structural information on the interaction between RTPases and their substrates were unsuccessful. In the present study, we used computational molecular docking to model the binding of a nucleotide substrate into the yeast RTPase active site. In order to confirm the docking model and to gain additional insights into the molecular determinants involved in substrate recognition, we also evaluated both the phosphohydrolysis and the inhibitory potential of an important number of nucleotide analogs. Our study highlights the importance of specific amino acids for the binding of the sugar, base and triphosphate moieties of the nucleotide substrate, and reveals both the structural flexibility and complexity of the active site. These data illustrate the functional features required for the interaction of an RTPase with a ligand and pave the way to the use of nucleotide analogs as potential inhibitors of RTPases of pathogenic importance

Poikilothermia in a 38-year-old Fabry patient

A Fabry patient with poikilothermia is described. Laboratory investigations, neuro-imaging and autonomic function tests did not disclose a cause. Assessment of intra-epidermal nerve fibre density and quantitative sensory testing revealed small fibre neuropathy with a highly impaired cold sensation. We speculate that the poikilothermia is either caused by a vascular lesion in the hypothalamus not visible on MRI or by small fibre neuropathy leading to disturbed body temperature perception and therefore impaired thermoregulation

Thalamocortical disconnection affects the somatic marker and social cognition: a case report

Thalamo-cortical connectivity was characterised in a patient with bilateral infarct of the thalami, without evidence of cognitive deficits in everyday life. Patient underwent social and emotional tests, Iowa Gambling Task (IGT), with and without concomitant heart rate variability (HRV) recording and at 3T-MRI to assess thalamo-cortical connectivity. Patient showed impairment at the IGT, in somatic marker, in emotions and theory of mind. MRI documented a bilateral damage of the centromedian-parafascicular complex. Patient's thalamic lesions disconnected brain areas involved in decision-making and autonomic regulation, affecting the somatic marker and resulting in the neuropsychological deficit exhibited by L.C

Partitioning the Heritability of Tourette Syndrome and Obsessive Compulsive Disorder Reveals Differences in Genetic Architecture

The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12) for TS, and 0.37 (se = 0.07, p = 1.5e-07) for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum) for which we had available expression quantitative trait loci (eQTLs). Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002). These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed) from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures

A multinational consensus on dysphagia in Parkinson's disease: screening, diagnosis and prognostic value

Background: Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a combination of motor and non-motor dysfunction. Dysphagia is a common symptom in PD, though it is still too frequently underdiagnosed. Consensus is lacking on screening, diagnosis, and prognosis of dysphagia in PD. Objective: To systematically review the literature and to define consensus statements on the screening and the diagnosis of dysphagia in PD, as well as on the impact of dysphagia on the prognosis and quality of life (QoL) of PD patients. Methods: A multinational group of experts in the field of neurogenic dysphagia and/or PD conducted a systematic revision of the literature published since January 1990 to February 2021 and reported the results according to PRISMA guidelines. The output of the research was then analyzed and discussed in a consensus conference convened in Pavia, Italy, where the consensus statements were drafted. The final version of statements was subsequently achieved by e-mail consensus. Results: Eighty-five papers were used to inform the Panel’s statements even though most of them were of Class IV quality. The statements tackled four main areas: (1) screening of dysphagia: timing and tools; (2) diagnosis of dysphagia: clinical and instrumental detection, severity assessment; (3) dysphagia and QoL: impact and assessment; (4) prognostic value of dysphagia; impact on the outcome and role of associated conditions. Conclusions: The statements elaborated by the Consensus Panel provide a framework to guide the neurologist in the timely detection and accurate diagnosis of dysphagia in PD