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Experimental and theoretical Brownian dynamics analysis of ion transport during cellular electroporation of E. coli bacteria
No full textCorresponding author: Juan A. González Cuevas, [email protected] acceso en línea a este artículo científico en versión de solo lectura ha sido compartido por los autores a través de Springer Nature SharedIt.El artículo es parte de la colección Electroporation for Medical Applications and Biotechnology.Escherichia coli bacterium is a rod-shaped organism composed of a complex double membrane structure. Knowledge of electric field driven ion transport through both membranes and the evolution of their induced permeabilization has important applications in biomedical engineering, delivery of genes and antibacterial agents. However, few studies have been conducted on Gram-negative bacteria in this regard considering the contribution of all ion types. To address this gap in knowledge, we have developed a deterministic and stochastic Brownian dynamics model to simulate in 3D space the motion of ions through pores formed in the plasma membranes of E. coli cells during electroporation. The diffusion coefficient, mobility, and translation time of Ca2+, Mg2+, Na+, K+, and Cl− ions within the pore region are estimated from the numerical model. Calculations of pore’s conductance have been validated with experiments conducted at Gustave Roussy. From the simulations, it was found that the main driving force of ionic uptake during the pulse is the one due to the externally applied electric field. The results from this work provide a better understanding of ion transport during electroporation, aiding in the design of electrical pulses for maximizing ion throughput, primarily for application in cancer treatment.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll
Feature selection : a perspective on inter-attribute cooperation
No full textCorresponding author. Correspondence to Gustavo Sosa Cabrera, [email protected] datasets depict a challenge for learning tasks in data mining and machine learning. Feature selection is an effective technique in dealing with dimensionality reduction. It is often an essential data processing step prior to applying a learning algorithm. Over the decades, filter feature selection methods have evolved from simple univariate relevance ranking algorithms to more sophisticated relevance-redundancy trade-offs and to multivariate dependencies-based approaches in recent years. This tendency to capture multivariate dependence aims at obtaining unique information about the class from the intercooperation among features. This paper presents a comprehensive survey of the state-of-the-art work on filter feature selection methods assisted by feature intercooperation, and summarizes the contributions of different approaches found in the literature. Furthermore, current issues and challenges are introduced to identify promising future research and development.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll
Diseño y fabricación de prototipo de planta móvil de potabilización de agua
No full textContacto: [email protected] proyecto ha tenido sus etapas bien separadas, desde el montaje de la Planta de Agua (PTA), el pedido a varias empresas/instituciones para poder usar sus instalaciones para las pruebas, y luego las diversas pruebas de campo con los desconocidos desafíos de las mismas, para los traslados desde el taller a Villeta, luego a Villa Hayes y finalmente a Itá Enramada para acercar la PTA al Río Paraguay. En las distintas etapas se han observado mejoras en el proceso, que fueron analizadas y ajustadas, lo que permitió llegar al objetivo.Consejo Nacional de Ciencia y TecnologíaPrograma de Innovación en Empresas Paraguayas. Proyectos Individuales de Innovación y Desarrollo Tecnológic
Experimental and theoretical Brownian dynamics analysis of ion transport during cellular electroporation of E. coli bacteria
No full textCorresponding author. Correspondence to Juan A. González Cuevas; [email protected] artículo es parte de la colección Electroporation for Medical Applications and Biotechnology.El acceso en línea a este artículo científico en versión de solo lectura ha sido compartido por los autores a través de Springer Nature SharedIt.Escherichia coli bacterium is a rod-shaped organism composed of a complex double membrane structure. Knowledge of electric field driven ion transport through both membranes and the evolution of their induced permeabilization has important applications in biomedical engineering, delivery of genes and antibacterial agents. However, few studies have been conducted on Gram-negative bacteria in this regard considering the contribution of all ion types. To address this gap in knowledge, we have developed a deterministic and stochastic Brownian dynamics model to simulate in 3D space the motion of ions through pores formed in the plasma membranes of E. coli cells during electroporation. The diffusion coefficient, mobility, and translation time of Ca2+, Mg2+, Na+, K+, and Cl− ions within the pore region are estimated from the numerical model. Calculations of pore’s conductance have been validated with experiments conducted at Gustave Roussy. From the simulations, it was found that the main driving force of ionic uptake during the pulse is the one due to the externally applied electric field. The results from this work provide a better understanding of ion transport during electroporation, aiding in the design of electrical pulses for maximizing ion throughput, primarily for application in cancer treatment.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll
CONSTANS-like genes are associated with flowering time in sesame
No full textCorresponding author. Correspondence to Julio César Masaru Iehisa, [email protected], [email protected] (Sesamum indicum L.) is an oilseed crop with high concentration of unsaturated fatty acids. It is produced in many developing countries of the tropical and subtropical regions. Despite its economic and social importance, limited genetic analyses were conducted on sesame to improve its yield. One of the yield-related traits is flowering time, which is crucial for the adaptation of crops to local environments and changing climatic conditions. To gain further insights into the molecular mechanisms behind the control of flowering in sesame, we searched homologs of FLOWERING LOCUS T (FT) and circadian clock-associated genes in the sesame genome. Then we compared their expression between early- and late-flowering sesame varieties before (10 days post-emergence [dpe]), around (20 dpe), and after flowering (30 dpe). Four copies of FT-like genes were found in sesame: SiFTL1/SiFT was up-regulated at 20 and 30 dpe and SiFTL2 at 30 dpe. SiFTL3 was poorly expressed throughout the three stages, and SiFTL4 was highly expressed at 10 dpe but not at later stages. These results suggest that SiFTL1/SiFT acts as florigen, and SiFTL4 could be a floral repressor. The CONSTANS-like genes SiCOL1 and SiCOL2 were highly expressed at 20 dpe suggesting its role as an inducer of florigen. In addition, the early-flowering sesame variety presented higher expression of SiFTL1/SiFT, SiFTL2, and SiCOL2 than the late-flowering variety at 20 dpe. The expression of SiGIs and circadian clock-related genes were similar between the two varieties. Our results suggest that SiCOLs or their regulator might be the causal gene for flowering time variation between the two sesame varieties studied.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll
Venomics of Leiurus abdullahbayrami, the most lethal scorpion in the Levant region of the Middle East
No full textThe scorpion Leiurus abdullahbayrami has been associated with severe/lethal envenomings throughout the Levant region of the Middle East, encompassing Turkey, Syria, and Lebanon, and only scarce information is available on its venom composition, activity, and antigenicity. We report on the composition of L. abdullahbayrami venom collected from Lebanese specimens using nESI-MS/MS, MALDI-TOF MS, SDS-PAGE and RP-HPLC. Venom lethality, through LD50 determination in mice (intraperitoneal), was also assessed (0.75 (0.16–1.09) mg/kg), confirming L.abdullahbayrami venom vertebrate toxicity. Fifty-four peaks were detected using RP-HPLC, half of which eluted in the gradient region between 20 and 40% acetonitrile. In reducing SDS-PAGE, most predominant components were <10 kDa, with minor components at higher molecular masses of 24.4, 43.1, and 48.9 kDa. Venom mass fingerprint by MALDI-TOF detected 21 components within the 1000–12,000 m/z range. Whole venom ‘shotgun’ bottom-up nLC-MS/MS approach, combined with in-gel tryptic digestion of SDS-PAGE bands, identified at least 113 different components belonging to 15 venom families and uncharacterized proteins, with ion channel-active components (K+ channel toxins (28); Na+ channel toxins (42); Cl− channel toxins (4); Ca+2 toxins (2)) being predominant. A single match for a L. adbullahbayrami NaTx was found in the UniProt database with other congeneric species, toxin h3.1 from Leiurus hebraeus, suggesting this might be an indication of venom divergence within Leiurus, eventhough this warrants further investigation involving venom proteomics and transcriptomics of relevant species. Considering such potential interspecific venom variation, future work should address whether preparation of a specific anti-L. abdullahbayrami antivenom is justified.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa de Repatriación y Radicación de Investigadores del ExteriorPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Fortalecimiento de infraestructura y equipamiento para la investigaciónPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa Nacional de Incentivo a los Investigadore
Abiotic drivers of bat community diversity in a savanna mosaic across the tropical/subtropical transition of South America
No full textCorresponding author: E-mail: [email protected] lies in an area of transition between the tropics and subtropics, and encompasses the interface of six South American ecoregions. Because of its central location within the climatic and biotic schema of the South American continent, Paraguay is ideal for exploring a variety of biogeographic and ecological questions. Several studies have evaluated the taxonomic, biogeographic and migratory status of the 59 species of bats currently recognized in Paraguay, and other studies have evaluated aspects of population genetics and community ecology of frugivorous bats in eastern Paraguayan forests. However, no study has evaluated the environmental factors influencing bat community structure within the mosaic of savanna ecoregions which extend over a majority of the Paraguayan territory. Based on conservative selection criteria, six bat communities from the Cerrado, Humid Chaco and Dry Chaco were evaluated in this study. Climatic data included a suite of temperature and precipitation parameters for each site. Latitude and longitude were also included as factors potentially predicting bat community parameters. Gini-Simpson diversity indices were calculated for each site, separately for species diversity, taxonomic diversity and trophic diversity. Environmental variables were evaluated for their associations with each of the three diversity indices. Significant differences were found among the six sites based on each of the three diversity indices. In general, precipitation variables are more influential than temperature variables in determining bat community diversity levels in Paraguayan savanna ecosystems. Species diversity can best be predicted with a linear combination of mean annual precipitation and mean precipitation of the driest month. Taxonomic diversity is best predicted using mean annual precipitation alone. In contrast, best prediction of trophic diversity is with mean precipitation of driest month. Species and taxonomic diversity patterns were generally concordant for the Cerrado and Humid Chaco communities, whereas trophic diversity was inconsistent among the Humid Chaco communities. An analysis of variance combining the three diversity indices, showed three non-significantly different groups of communities: (1) the two Dry Chaco communities; (2) a Dry Chaco and a Humid Chaco community; and (3) the Cerrado and three Humid Chaco localities. These results should be considered in bat conservation management strategies, which should incorporate benchmarks not only of species diversity, but also of taxonomic and trophic diversity.Paraguay se encuentra en un área de transición entre los trópicos y subtrópicos, abarcando una interfaz de seis ecorregiones sudamericanas. Por su ubicación central a nivel climático y biótico del continente sudamericano, es ideal para presentar diferentes preguntas biogeográficas y ecológicas. Varios estudios han evaluado el estado taxonómico, biogeográfico y migratorio de las 59 especies de murciélagos actualmente registradas, otros han evaluado aspectos de genética poblacional y ecología de comunidades de murciélagos frugívoros en los bosques del este de Paraguay, pero ninguno ha evaluado los factores ambientales que influyen en la estructura de la comunidad dentro del mosaico de ecorregiones de sabana que se extienden sobre gran parte del territorio. Se evaluaron seis comunidades de murciélagos, considerando criterios conservadores de selección. Los datos climáticos incluyeron parámetros de temperatura y precipitación para cada sitio. La latitud y la longitud se incluyen como potenciales factores para predecir parámetros de la comunidad. Se calcularon por separado, índices de diversidad de Gini-Simpson para cada sitio, para diversidad de especies, diversidad taxonómica y diversidad trófica. Así también, variables ambientales fueron evaluadas y asociadas con cada índice de diversidad. Se registraron diferencias significativas entre los seis sitios con respecto a los tres índices de diversidad. Las variables de precipitación influyen más que las de temperatura para determinar los niveles de diversidad de la comunidad en ecosistemas de sabana. La diversidad de especies fue determinada utilizando la combinación lineal de precipitación media anual y precipitación media del mes más seco. La diversidad taxonómica se predice mejor utilizando únicamente la precipitación media anual. La predicción de la diversidad trófica es más compleja, ya que combina la precipitación media anual, error estándar de precipitación media anual, precipitación media del mes más seco y rango de temperatura diurna media. Los patrones de diversidad taxonómica y de especies fueron semejantes para comunidades del Cerrado y Chaco Húmedo, mientras que la diversidad trófica fue inconsistente entre comunidades del Chaco Húmedo. El análisis de la varianza de los tres índices de diversidad juntos, mostró que tres grupos de comunidades no presentaron diferencias significativas: las dos comunidades del Chaco Seco; una del Chaco Seco y una del Chaco Húmedo; la del Cerrado y tres localidades del Chaco Húmedo. Estos resultados deben ser considerados para estrategias de manejo de conservación, incorporando puntos de referencia no solo de diversidad de especies, sino también de diversidad taxonómica y diversidad trófica.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa Nacional de Incentivo a los Investigadore
Universo microscópico
No full textFotografía ganadora del Segundo Puesto del III Concurso Nacional de Fotografía Científica del CONACYT, en la categoría Fotógrafo Aficionado y con la temática “Semillas que alimentan”. El tema forma parte del concurso en concordancia con la declaración realizada por la Asamblea General de las Naciones Unidas, enunciando el año 2023 como Año Internacional del Mijo, con el objetivo de combatir el hambre, contribuir a la seguridad alimentaria, la nutrición y mejorar la diversidad del sistema alimentario. El concurso es una iniciativa del CONACYT, a través del Programa PROCIENCIA II con apoyo del Fondo para la Excelencia de la Educación y la Investigación (FEEI).Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Concursos de divulgación de ciencia y periodismo científic
Performance of cervical cytology and HPV testing for primary cervical cancer screening in Latin America : an analysis within the ESTAMPA study
Get PDFCorresponding author. E-mail address: [email protected] (A.T. Ramírez).Artículo científico premiado con una Mención Honorífica por el Premio Nacional de Ciencias de la edición 2024, otorgado por la Honorable Cámara de Senadores del Congreso Nacional de la República del Paraguay.Background. Cervical cytology remains widely used as the initial tool in cervical cancer screening worldwide. WHO guidelines recommend replacing cytology with primary HPV testing to reach cervical cancer elimination goals. We assessed the performance of cytology and high-risk HPV testing to detect cervical precancer, cervical intraepithelial neoplasia (CIN) grade 3 or worse (CIN3+) among women aged 30–64 years participating in the ESTAMPA study.
Methods. Women were screened with cytology and HPV across ESTAMPA study centres in Latin America. Screen-positives were referred to colposcopy with biopsy collection and treatment as needed. Those with no evident precancer were recalled at 18-months for a second HPV test to complete disease ascertainment. Performance indicators for cytology and HPV to detect CIN3+ were estimated.
Findings. 30,606 participants with available cytology and HPV results were included in the analysis. A total of 440 histologically confirmed CIN3s and 30 cancers were diagnosed. Cytology sensitivity for CIN3+ was 48.5% (95% CI: 44.0–53.0), whereas HPV testing had a sensitivity of 98.1% (95% CI: 96.3–96.7). Specificity was 96.5% (95% CI: 96.3–96.7) using cytology and 88.7% (95% CI: 88.3–89.0) with HPV. Performance estimates varied substantially by study centre for cytology (ranging from 32.1% to 87.5% for sensitivity and from 89.2% to 99.5% for specificity) while for HPV results were more consistent across sites (96.7%–100% and 83.6–90.8%, respectively).
Interpretation. The limited and highly variable sensitivity of cytology strongly supports transition to the more robust and reproducible HPV-based cervical screening to ensure progress towards global cervical cancer elimination targets in Latin America.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll
Microcrystals and microfibers of cellulose from Acrocomia aculeata (Arecaceae) characterization
No full textCorrespondence: [email protected] (S.D.); [email protected] (M.C.P.).In the context of the so-called lignocellulose bio-refinery, the coconut shell (S) and pulp (P) of Acrocomia aculeata (Arecaceae) are interesting agro-industrial wastes that can be used as feedstock for the production of high value-added products. The aim of this work was to evaluate these lignocellulosic residues S and P, to obtain the microcrystal (MCC) and microfiber (MFC) of cellulose, and to characterize them to propose possible applications. First, cellulose content in the raw materials was determined, being 39.69% and 45.42% for both (S and P)) respectively, respectively. Then, the purification of residues was carried out via alkaline and bleaching treatments. Next, in order to obtain MCC and MFC from the purified cellulose, a chemical treatment with HCl (for MCC) and a mechanical treatment with a blender (for MFC) were performed. The size and morphology were observed via MEB, and properties were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential thermogravimetric analysis (DTG).Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarrolloPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa Nacional de Incentivo a los Investigadore