Competencias en información en contextos de educación media pública en Montevideo, Uruguay

This article presents the main results and conclusions of an R&D project that aimed to recognize information skills in first-year students of public high schools in Montevideo, Uruguay, as it is understood that this moment of their educational journey serves as a turning point at the end of the primary cycle and the beginning of their schooling in secondary education. The research used a mainly quantitative methodology, in which a web form was applied with activities linked to the different information competencies expected for students of the aforementioned level and, from said form, the results were studied. The article presents the main results obtained from the activities carried out by the students. As main results, various difficulties of students are evident when determining what their information needs are, designing search strategies and evaluating and selecting information sources. It is concluded that it is necessary to integrate in a more concrete way instances of teaching and learning whose objective is the construction of competencies in information.El artículo presenta los principales resultados y conclusiones de un proyecto I+D que tuvo por objetivo reconocer competencias en información en estudiantes de primer año de liceos públicos de Montevideo, Uruguay, por entender que ese momento de su trayecto formativo oficia como punto de inflexión entre el fin del ciclo de primaria y el inicio de su escolarización en la educación media secundaria. La investigación se sirvió de una metodología principalmente cuantitativa, en la que se aplicó un formulario web con actividades vinculadas a las diferentes competencias en información esperadas para estudiantes del nivel mencionado y, a partir de las actividades realizadas por los estudiantes se procedió a estudiar los resultados. Principalmente, se evidencian diversas dificultades de los estudiantes a la hora de determinar cuáles son sus necesidades de información, de diseñar estrategias de búsqueda y de evaluar y seleccionar las fuentes de información. Se concluye que es necesario integrar de manera más concreta instancias de enseñanza y aprendizaje cuyo objetivo sea la construcción de competencias en información. &nbsp

Effect of ATG12-ATG5-ATG16L1 autophagy E3 complex on the ability of LC3/GABARAP proteins to induce

Trabajo presentado en el 44º Congreso Nacional de la Sociedad Española de Bioquímica y Biología Molecular (SEBBM), celebrado en Málaga entre el 6 y el 9 de septiembre de 2022.In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12–ATG5-ATG16L1 (E3) complex acts as a ubiquitin-like E3 ligase enzyme, promoting LC3/GABARAP protein anchoring to the AP membrane. The role of the various proteins in the AP expansion process is still unclear, in part because there are no studies comparing LC3/GABARAP-family member roles under the same conditions, and also because the full human E3 complex was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However E3 hampers LC3/GABARAP capacity to induce intervesicular lipid mixing or subsequent fusion, presumably through formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulation should exist to inhibit the formation of an E3 immobile scaffold

E3 autophagy complex and LC3/GABARAP proteins in autophagosome generation

Póster presentado al 8th International Iberian Biophysics Congress celebrado en Bilbao los días 20 y 21 de junio de 2022.In macroautophagy, autophagosome (AP) formation in humans requires the concerted action of the LC3/GABARAP and ATG12 ubiquitin-like conjugation systems. In the present study, the conjugation to the membrane of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of the product of the ATG12 system (the E3 complex). In addition, the mechanisms by which the different LC3/GABARAP proteins and E3 could participate in vesicle tethering and fusion during AP expansion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulation should exist to inhibit the formationof an E3 immobile scaffold

LC3 subfamily in cardiolipin-mediated mitophagy: a comparison of the LC3A, LC3B and LC3C homologs

Externalization of the phospholipid cardiolipin (CL) to the outer mitochondrial membrane has been proposed to act as a mitophagy trigger. CL would act as a signal for binding the LC3 macroauto-phagy/autophagy proteins. As yet, the behavior of the LC3-subfamily members has not been directly compared in a detailed way. In the present contribution, an analysis of LC3A, LC3B and LC3C interaction with CL-containing model membranes, and of their ability to translocate to mitochondria, is described. Binding of LC3A to CL was stronger than that of LC3B; both proteins showed a similar ability to colocalize with mitochondria upon induction of CL externalization in SH-SY5Y cells. Besides, the double silencing of LC3A and LC3B proteins was seen to decrease CCCP-induced mitophagy. Residues 14 and 18 located in the N-terminal region of LC3A were shown to be important for its recognition of damaged mitochondria during rotenone- or CCCP-induced mitophagy. Moreover, the in vitro results suggested a possible role of LC3A, but not of LC3B, in oxidized-CL recognition as a counterweight to excessive apoptosis activation. In the case of LC3C, even if this protein showed a stronger CL binding than LC3B or LC3A, the interaction was less specific, and colocalization of LC3C with mitochondria was not rotenone dependent. These results suggest that, at variance with LC3A, LC3C does not participate in cargo recognition during CL-mediated-mitophagy. The data support the notion that the various LC3-subfamily members might play different roles during autophagy initia-tion, identifying LC3A as a novel stakeholder in CL-mediated mitophagy.This work was supported in part by the Spanish Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (grant No. PGC2018-099857- B-I00), by the Basque Government (grants No. IT1625-22 and IT1270- 19), by Fundación Ramón Areces (CIVP20A6619), by Fundación Biofísica Bizkaia and by the Basque Excellence Research Centre (BERC) program of the Basque Government. MI and YV were recipients of predoctoral FPU fellowships from the Spanish Ministry of Science Innovation and Universities (FPU16/05873, FPU18/00799), UB thanks the University of the Basque Country for a predoctoral contract, JHH was supported by a Postdoctoral Fellowship from the Basque Government

Lipids in Mitochondrial Macroautophagy: Phase Behavior of Bilayers Containing Cardiolipin and Ceramide

Cardiolipin (CL) is a key lipid for damaged mitochondrial recognition by the LC3/GABARAP human autophagy proteins. The role of ceramide (Cer) in this process is unclear, but CL and Cer have been proposed to coexist in mitochondria under certain conditions. Varela et al. showed that in model membranes composed of egg sphingomyelin (eSM), dioleoyl phosphatidylethanolamine (DOPE), and CL, the addition of Cer enhanced the binding of LC3/GABARAP proteins to bilayers. Cer gave rise to lateral phase separation of Cer-rich rigid domains but protein binding took place mainly in the fluid continuous phase. In the present study, a biophysical analysis of bilayers composed of eSM, DOPE, CL, and/or Cer was attempted to understand the relevance of this lipid coexistence. Bilayers were studied by differential scanning calorimetry, confocal fluorescence microscopy, and atomic force microscopy. Upon the addition of CL and Cer, one continuous phase and two segregated ones were formed. In bilayers with egg phosphatidylcholine instead of eSM, in which the binding of LC3/GABARAP proteins hardly increased with Cer in the former study, a single segregated phase was formed. Assuming that phase separation at the nanoscale is ruled by the same principles acting at the micrometer scale, it is proposed that Cer-enriched rigid nanodomains, stabilized by eSM:Cer interactions formed within the DOPE- and CL-enriched fluid phase, result in structural defects at the rigid/fluid nanointerfaces, thus hypothetically facilitatingLC3/GABARAP protein interaction.This work was funded in part by the Spanish Ministry of Science, Innovation, and Universities (MCIU), Agencia Estatal de Investigación (AEI), Fondo Europeo de Desarrollo Regional (FEDER) (grant No. PID2021-124461NB-I00), the Basque Government (grant No. IT1625-22), Fundación Ramón Areces (CIVP20A6619), Fundación Biofísica Bizkaia, and the Basque Excellence Research Centre (BERC) program of the Basque Government. E.J.G.-R. was supported by Fundación Ramón Areces. M.N.I. and Y.R.V. were recipients of pre-doctoral FPU fellowships from the Spanish Ministry of Science, Innovation, and Universities (FPU16/05873, FPU18/00799). U.B. thanks the University of the Basque Country for a pre-doctoral contract

Endophytic Bacteria From the Roots of the Medicinal Plant Alkanna tinctoria Tausch (Boraginaceae): Exploration of Plant Growth Promoting Properties and Potential Role in the Production of Plant Secondary Metabolites

Alkannin and shikonin (A/S) are enantiomeric naphthoquinones produced in the roots of certain plants from the Boraginaceae family such as Lithospermum spp. and Alkanna spp. They possess antimicrobial, anti-tumoral and wound healing properties. The production of secondary metabolites by Alkanna tinctoria might be influenced by its endomicrobiome. To study the interaction between this medicinal plant and its bacterial endophytes, we isolated bacteria from the roots of wild growing Alkanna tinctoria collected near to Athens and Thessaloniki in Greece. Representative strains selected by MALDI-TOF mass spectrometry were identified by partial 16S rRNA gene sequence analysis. In total, 197 distinct phylotypes of endophytic bacteria were detected. The most abundant genera recovered were Pseudomonas, Xanthomonas, Variovorax, Bacillus, Inquilinus, Pantoea, and Stenotrophomonas. Several bacteria were then tested in vitro for their plant growth promoting activity and the production of cell-wall degrading enzymes. Strains of Pseudomonas, Pantoea, Bacillus and Inquilinus showed positive plant growth properties whereas those of Bacteroidetes and Rhizobiaceae showed pectinase and cellulase activity in vitro. In addition, bacterial responses to alkannin and shikonin were investigated through resistance assays. Gram negative bacteria were found to be resistant to the antimicrobial properties of A/S, whereas the Gram positives were sensitive. A selection of bacteria was then tested for the ability to induce A/S production in hairy roots culture of A. tinctoria. Four strains belonging to Chitinophaga sp., Allorhizobium sp., Duganella sp., and Micromonospora sp., resulted in significantly more A/S in the hairy roots than the uninoculated control. As these bacteria can produce cell-wall degrading enzymes, we hypothesize that the A/S induction may be related with the plant-bacteria interaction during colonization

Effect of ATG12–ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion

In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12–ATG5-ATG16L1 or E3-like complex (E3 for short) acts as a ubiquitin-like E3 enzyme, promoting LC3/GABARAP proteins anchoring to the AP membrane. Their role in the AP expansion process is still unclear, in part because there are no studies comparing six LC3/GABARAP family member roles under the same conditions, and also because the full human E3 was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through the formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulatory mechanism would allow vesicle incorporation and phagophore growth when E3 is present.This work was supported in part by the Spanish Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (grants No. PGC2018-099857-B-I00 and PID2021-124461NB-I00), by the Basque Government (grants No. IT1625-22 and IT1270-19), by Fundación Biofísica Bizkaia, by Fundación Ramón Areces (grant No. CIVP20A6619), and by the Basque Excellence Research Centre (BERC) program of the Basque Government. MI and YV were recipients of predoctoral FPU fellowships from the Spanish Ministry of Science, Innovation and Universities (FPU16/05873, FPU18/00799), UB thanks the University of the Basque Country for a predoctoral contract. This work was supported by Human Frontiers Science Program RGP0026/2017 (S.M.)

Effect of ATG12-ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion

In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12-ATG5-ATG16L1 or E3-like complex (E3 for short) acts as a ubiquitin-like E3 enzyme, promoting LC3/GABARAP proteins anchoring to the AP membrane. Their role in the AP expansion process is still unclear, in part because there are no studies comparing six LC3/GABARAP family member roles under the same conditions, and also because the full human E3 was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through the formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulatory mechanism would allow vesicle incorporation and phagophore growth when E3 is present.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported in part by the Spanish Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (grants No. PGC2018-099857-B-I00 and PID2021-124461NB-I00), by the Basque Government (grants No. IT1625-22 and IT1270-19), by Fundación Biofísica Bizkaia, by Fundación Ramón Areces (grant No. CIVP20A6619), and by the Basque Excellence Research Centre (BERC) program of the Basque Government. MI and YV were recipients of predoctoral FPU fellowships from the Spanish Ministry of Science, Innovation and Universities (FPU16/05873, FPU18/00799), UB thanks the University of the Basque Country for a predoctoral contract. This work was supported by Human Frontiers Science Program RGP0026/2017 (S.M.).Peer reviewe

Supplementary Information for Effect of ATG12–ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion

15 pages. -- This file includes: Supp. Fig. 1-13. -- Supp. Table 1. List of protein constructs used in this work: vector, expression system, detailed protein encoded, and reference study.Peer reviewe

Mitochondrial cristae-remodeling protein OPA1 in POMC neurons couples Ca2+ homeostasis with adipose tissue lipolysis

© 2021 The Authors.Appropriate cristae remodeling is a determinant of mitochondrial function and bioenergetics and thus represents a crucial process for cellular metabolic adaptations. Here, we show that mitochondrial cristae architecture and expression of the master cristae-remodeling protein OPA1 in proopiomelanocortin (POMC) neurons, which are key metabolic sensors implicated in energy balance control, is affected by fluctuations in nutrient availability. Genetic inactivation of OPA1 in POMC neurons causes dramatic alterations in cristae topology, mitochondrial Ca2+ handling, reduction in alpha-melanocyte stimulating hormone (α-MSH) in target areas, hyperphagia, and attenuated white adipose tissue (WAT) lipolysis resulting in obesity. Pharmacological blockade of mitochondrial Ca2+ influx restores α-MSH and the lipolytic program, while improving the metabolic defects of mutant mice. Chemogenetic manipulation of POMC neurons confirms a role in lipolysis control. Our results unveil a novel axis that connects OPA1 in POMC neurons with mitochondrial cristae, Ca2+ homeostasis, and WAT lipolysis in the regulation of energy balance.This work was supported by Agencia Estatal de Investigación y Fondo Social Europeo, Proyecto BFU2016-76973-R FEDER (C.V.A.); AG052005, AG052986, AG051459, DK111178 from NIH and NKFI-KKP-126998 from Hungarian National Research, Development and Innovation Office (T.L.H.); MR/P009824/2 from Medical Research Council UK (G.D.); and Ayudas Fundación BBVA a Investigadores y Creadores Culturales (2015), European Research Council (ERC) under the European Union’s Horizon 2020 Research And Innovation Program (grant agreement 725004) and CERCA Programme/Generalitat de Catalunya (M.C.). A.O. is supported by a Miguel Servet contract (CP19/00083) from Instituto de Salud Carlos III and co-financed by FEDER