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La expresión artística de la escritura y el movimiento dancístico como espacio de encuentro intergeneracional entre la niñez, la adolescencia y la adultez mayor en el cantón central de San Ramón
(2025) Herrera González, Damián
En el siguiente video se resaltan los principales hallazgos del proyecto de investigación "La expresión artística de la escritura y el movimiento dancístico como espacio de encuentro intergeneracional entre la niñez, la adolescencia y la adultez mayor en el cantón central de San Ramón"
Paisajes hortícolas de altura de la Cordillera Volcánica Central de Costa Rica. Procesos, dinámicas y oportunidades de mejora
(2025) León Alfaro, Yazmín
En el siguiente video se resaltan los principales hallazgos del proyecto de investigación "Paisajes hortícolas de altura de la Cordillera Volcánica Central de Costa Rica. Procesos, dinámicas y oportunidades de mejora"
Unveiling oral anaerobic bacteria outer membrane vesicles: A comprehensive systematic review
(2024-04-26) Castro Vargas, Priscilla; Barloy Hubler, Frédérique; Acuña Amador, Luis Alberto
Extracellular vesicles (EV) are spherical structures limited by membranes and shed by several cell types. Specifically, outer membrane vesicles (OMVs) are nanometric particles constitutively produced by Gram-negative bacteria (GNB) under different environmental conditions. OMVs are biologically active; they are loaded with selected lipids, polysaccharides, proteins, and even different types of nucleic acids. OMVs from pathogenic oral bacteria play key roles in pathogen-host interactions, constituting a possible link between oral health and systemic disease. OMVs participate in adhesion, invasion, and damage to cells, as well as in modulating the host's immune response, biofilm formation, and promotion of virulence. The objective of this systematic review was to collect, analyze and synthesize the knowledge available on literature reviews on OMVs of the most studied pathogenic oral anaerobic GNB. This information was classified into the following categories: induction of vesiculation and biogenesis, its liberation from the parental cell, content, internalization by another host cell, and the interaction with the host cell. It was found that the most studied OMVs are those of Porphyromonas gingivalis and Bacteroides spp. and, to a lesser extent, Aggregatibacter spp., and Treponema spp. This systematic review provides a synthesis of the current knowledge regarding OMVs, with emphasis on the information available for periodontopathogens.
In silico analysis of Ffp1, an ancestral Porphyromonas spp. fimbrillin, shows differences with Fim and Mfa
(2024) Acuña Amador, Luis Alberto; Barloy Hubler, Frédérique
Background. Scant information is available regarding fimbrillins within the genus Porphyromonas, with the notable exception of those belonging to Porphyromonas gingivalis, which have been extensively researched for several years. Besides fim and mfa, a third P. gingivalis adhesin called filament-forming protein 1 (Ffp1) has recently been described and seems to be pivotal for outer membrane vesicle (OMV) production. Objective. We aimed to investigate the distribution and diversity of type V fimbrillin, particularly Ffp1, in the genus Porphyromonas. Methods. A bioinformatics phylogenomic analysis was conducted using all accessible Porphyromonas genomes to generate a domain search for fimbriae, using hidden Markov model profiles. Results. Ffp1 was identified as the sole fimbrillin present in all analysed genomes. After manual verification (i.e. biocuration) of both structural and functional annotations and 3D modelling, this protein was determined to be a type V fimbrillin, with a closer structural resemblance to a Bacteroides ovatus fimbrillin than to FimA or Mfa1 from P. gingivalis. Conclusion. It appears that Ffp1 is an ancestral fimbria, transmitted through vertical inheritance and present across all Porphyromonas species. Additional investigations are necessary to elucidate the biogenesis of Ffp1 fimbriae and their potential role in OMV production and niche adaptation.
Preclinical antivenom-efficacy testing reveals potentially disturbing deficiencies of snakebite treatment capability in East Africa
(2017-10-18) Harrison, Robert A.; Oluoch, George Omondi; Ainsworth, Stuart; Alsolaiss, Jaffer Ali; Bolton, Fiona M. S.; Arias Oviedo, Ana Silvia; Gutiérrez, José María; Rowley, Paul D.; Kalya, Stephen; Ozwara Suba, Hastings; Casewell, Nicholas R.
Background. Antivenom is the treatment of choice for snakebite, which annually kills an estimated 32,000 people in sub-Saharan Africa and leaves approximately 100,000 survivors with permanent physical disabilities that exert a considerable socioeconomic burden. Over the past two decades, the high costs of the most polyspecifically-effective antivenoms have sequentially reduced demand, commercial manufacturing incentives and production volumes that have combined to create a continent-wide vacuum of effective snakebite therapy. This was quickly filled with new, less expensive antivenoms, many of which are of untested efficacy. Some of these successfully marketed antivenoms for Africa are inappropriately manufactured with venoms from non-African snakes and are dangerously ineffective. The uncertain efficacy of available antivenoms exacerbates the complexity of designing intervention measures to reduce the burden of snakebite in sub-Saharan Africa. The objective of this study was to preclinically determine the ability of antivenoms available in Kenya to neutralise the lethal effects of venoms from the most medically important snakes in East Africa. Methods. We collected venom samples from the most medically important snakes in East Africa and determined their toxicity in a mouse model. Using a ‘gold standard’ comparison protocol, we preclinically tested the comparative venom-neutralising efficacy of four antivenoms available in Kenya with two antivenoms of clinically-proven efficacy. To explain the variant efficacies of these antivenoms we tested the IgG-venom binding characteristics of each antivenom using in vitro IgG titre, avidity and venom-protein specificity assays. We also measured the IgG concentration of each antivenom. Findings. None of the six antivenoms are preclinically effective, at the doses tested, against all of the most medically important snakes of the region. The very limited snake polyspecific efficacy of two locally available antivenoms is of concern. In vitro assays of the abilities of ‘test’ antivenom IgGs to bind venom proteins were not substantially different from that of the ‘gold standard’ antivenoms. The least effective antivenoms had the lowest IgG content/vial. Conclusions. Manufacture-stated preclinical efficacy statements guide decision making by physicians and antivenom purchasers in sub-Saharan Africa. This is because of the lack of both clinical data on the efficacy of most of the many antivenoms used to treat patients and independent preclinical assessment. Our preclinical efficacy assessment of antivenoms available in Kenya identifies important limitations for two of the most commonly-used antivenoms, and that no antivenom is preclinically effective against all the regionally important snakes. The potential implication to snakebite treatment is of serious concern in Kenya and elsewhere in sub-Saharan Africa, and underscores the dilemma physicians face, the need for clinical data on antivenom efficacy and the medical and societal value of establishing independent preclinical antivenom-efficacy testing facilities throughout the continent.