Development of COVID-19 monoclonal antibodies and recombinant proteins as reagents for biomedical research and diagnostic test

Since SARS-COV-2 virus spread worldwide and COVID-19 turned rapidly into a pandemic illness, the necessity for vaccines and diagnostic tests became crucial. The viral surface is decorated with Spike, the major antigenic determinant and main target for vaccine development. Within Spike, the receptor binding domain (RBD), constitutes the main target of highly neutralizing antibodies found in COVID-19 convalescent plasma. Besides vaccination, another important aspect of Spike (and RBD) is their use as immunogen for the development of poli- and monoclonal antibodies (mAbs) for therapeutic and diagnostic purposes. Here we report the development and preliminary biochemical characterization of a set of monoclonal antibodies against the Spike RBD domain along with the recombinant expression of two mayor COVID-19 protein reagents: the viral Spike RBD domain and the extracellular domain of the human receptor ACE2. RBD and the extracellular domain of ACE2 (aa 1-740) were obtained through transient gene transfection (TGE) in two different mammalian cell culture systems: HEK293T adherent monolayers and Expi293 suspension cultures. Due to its low cost and ease scale-up, all transfections were carried with polyethyleneimine (PEI). Expressed proteins were purified from culture supernatants by immobilized metal affinity chromatography. Anti-RBD mAbs were developed from two different immunization schemes: one aimed to elicit antibodies with viral neutralizing potential, and the other with the ability to recognize denatured RBD for routinary lab immunoassays. To achieve this, the first group of mice was immunized with RBD in aluminium salts (RBD/Al) and the other with RBD emulsified in Freunds adyuvant (RBD/FA). Polyclonal and monoclonal antibody reactivities against native or denatured RBD forms were then assessed by ELISA. Complete RBD denaturation was followed by intrinsic fluorescence spectral changes upon different physicochemical stress treatments. As expected, RBD/Al immunized mice developed an antibody response shifted to native RBD while those immunized with RBD/FA showed a high response against both forms of the protein. In accordance with the observed polyclonal response, RBD/FA derived mAbs recognize both, native and denatured RBD. On the contrary, hybridomas generated from the RBD/Al protocol mostly recognize RBD in its native state. Further ELISA binding assays revealed that all RBD/FA derived mAbs can form a trimeric complex with ACE2 and RBD, denoting they would not have viral neutralizing activity. ELISA competition assays with the RBD/ACE2 complex aimed to determine the neutralization potential of the RBD/Al derived mAbs are under way. Overall, the anti-Spike RBD mAbs and the recombinant RBD and ACE2 proteins presented here constitute valuable tools for diverse COVID-19 academic research projects and local immunity surveillance testing.Fil: Acuña Intrieri, M. E. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Deriane, M.A. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Miller, C.. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Czibener, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Correa, E.. No especifíca;Fil: Cragnaz, L.. No especifíca;Fil: Guerra, L.. No especifíca;Fil: Rodriguez, S.. No especifíca;Fil: Goldbaum, F.A.. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Seigelchifer, M.. No especifíca;Fil: Comerci, Diego José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Montagna, Georgina Nuri. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Cerutti, Maria Laura. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaLVII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research y XVI Annual Meeting of the Argentinean Society for General MicrobiologyVirtualArgentinaSociedad Argentina de Investigación Bioquímica y Biología MolecularAsociación Civil de Microbiología Genera

Duas décadas de Acta Colombiana de Psicología: uma análise bibliométrica

The aim of the present study was to conduct a bibliometric analysis of the journal Acta Colombiana de Psicología, by virtue of its two decades of uninterrupted work (1998-2017). Initially, historical elements are described in the trajectory of the journal and its chronological evolution is revealed from a database that in its final sample took into account 388 scientific articles. Subsequently, the appraisal of the productivity indices (Lotka) as well as of the topics and methodologies used was carried out. Likewise, an appraisal of the collaboration indicators and the relationships between the authors with respect to the signatory countries was performed. The results highlight the large number of papers from Mexican institutions, a sustained increase in collaboration is visualized -which is evident in the Lawani and Subramanyam indices-, and it is found that the largest amount of papers focused on the areas of clinical and health psychology. The analysis undertaken allows showing what the journal has achieved throughout two decades of scientific work during which it contributed fundamentally to the development of psychology in Latin America.O objetivo do presente estudo foi realizar uma análise bibliométrica da revista Acta Colombiana de Psicología, devido a suas duas décadas de trabalho ininterrupto (1998-2017). Inicialmente, descrevem-se elementos históricos na trajetória da revista e revela-se sua evolução cronológica a partir de uma base de dados que considerou 388 artigos científicos em sua amostra final. Posteriormente, foram realizadas as análises dos índices de produtividade (Lotka) e das temáticas e metodologias utilizadas. Além disso, foi desenvolvida uma análise dos indicadores de colaboração e das relações entre os autores com respeito aos países signatários. Nos resultados, destaca-se a grande quantidade de trabalhos provenientes de instituições mexicanas, visualiza-se uma alta prolongada na colaboração - o que se evidencia nos índices de Lawani e Subramanyam -, e nota-se que a maior quantidade de trabalhos concentrou-se nas áreas de psicologia clínica e da saúde. A análise realizada permite exibir o feito da revista ao longo de duas décadas de trabalho científico nas quais colaborou de maneira fundamental para o desenvolvimento da psicologia na América espanhola.El objetivo del presente estudio fue realizar un análisis bibliométrico de la revista Acta Colombiana de Psicología, debido a sus dos décadas de trabajo ininterrumpido (1998-2017). Inicialmente, se describen elementos históricos en la trayectoria de la revista y se releva su evolución cronológica a partir de una base de datos que consideró 388 artículos científicos en su muestra final; posteriormente, se realizaron los análisis de los índices de productividad (Lotka) y de las temáticas y metodologías utilizadas. Asimismo, se desarrolló un análisis de los indicadores de colaboración y de las relaciones entre los autores con respecto a los países firmantes. En los resultados se destaca la gran cantidad de trabajos provenientes de instituciones mexicanas, se visualiza un alza sostenida en la colaboración -lo que se evidencia en los índices de Lawani y Subramanyam-, y se encuentra que la mayor cantidad de trabajos se enfocó en las áreas de psicología clínica y de la salud. El análisis realizado permite exhibir lo realizado por la revista a lo largo de dos décadas de trabajo científico en las que se aportó de manera fundamental al desarrollo de la psicología en Hispanoamérica

H2 oxidation versus organic substrate oxidation in non-heme iron mediated reactions with H2O2

Herein we show that species generated upon reaction of α-[Fe(CF3SO3)2(BPMCN)] (BPMCN = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane) with H2O2 (putatively [FeV(O)(OH)(BPMCN)]) is able to efficiently oxidize H2 to H2O even in the presence of organic substrates, while species formed in the presence of acetic acid (putatively [FeV(O)(OAc)(BPMCN)]) prefer organic substrate oxidation over H2 activation. Mechanistic implications have been analysed with the aid of computational methodsThis work was supported by Spanish Ministerio de Economia y Competitividad (CTQ2012-37420-C02-02 and 01) European Research Council (StG 239910), and Generalitat de Catalunya (2014 SGR 862 and ICREA Academia award to MC). J.Ll.-F. thanks the CELLEX foundation for the starting career program for financial suppor

Anatomy and histochemistry of leaves, stem and xylopodium of Gomphrena perennis L.

Gomphrena perennis L. es una hierba perenne nativa,distribuida en el norte y centro de Argentina,a la cual se le atribuyen propiedades emolientes,diuréticas, depurativas, estomacales, febrífugas, antirreumáticasy antidiarreicas. Nuestro objetivo fueestudiar la anatomía de hoja, tallo y xilopodio deG. perennis y realizar pruebas histoquímicas paradetectar sustancias ergásticas, para lo cual se recolectaronplantas en las cimas y laderas de Sierra deLos Padres y La Vigilancia, pcia. de Buenos Aires.Se diafanizaron hojas mediante la técnica de clarificación5-5-5, para caracterizar su epidermis. Serealizaron cortes transversales (C.T.) de materialfresco de los órganos y se tiñó con colorantes ortocromáticosy metacromáticos para observar la disposición de los tejidos. Además, se realizaron pruebashistoquímicas para determinar almidón, aceites,taninos y mucílagos. En la hoja, el diafanizadomostró una disposición estomática de tipo anomocítica,y el C.T. una anatomía tipo Kranz y drusasentre los haces vasculares. Además, se observarontricomas epidérmicos no glandulares. En el tallo seobservó colénquima angular subepidérmico, un crecimientosecundario anómalo, drusas, y se evidenciócontenido de almidón. Si bien los análisis histoquímicospreliminares no demostraron la presenciade aceites, mucílagos y taninos, se continuarácon los estudios para identificar posibles principiosactivos presentes en plantas que crecen en las sierrasde Buenos Aires.Fil: Acuña, A. L. A.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Thevenon, Mario. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Martinez Tosto, Ana Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones en Sanidad Producción y Ambiente. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigaciones en Sanidad Producción y Ambiente; ArgentinaFil: Fernández Honaine, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cardinali, Francisco José. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones en Sanidad Producción y Ambiente. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigaciones en Sanidad Producción y Ambiente; ArgentinaXXXVIII Jornadas Argentinas de BotánicaEntre RíosArgentinaSociedad Argentina de Botánic

A theory of nonvertical triplet energy transfer in terms of accurate potential energy surfaces: The transfer reaction from π,π∗ triplet donors to 1,3,5,7-cyclooctatetraene

Triplet energy transfer (TET) from aromatic donors to 1,3,5,7-cyclooctatetraene (COT) is an extreme case of “nonvertical” behavior, where the transfer rate for low-energy donors is considerably faster than that predicted for a thermally activated (Arrhenius) process. To explain the anomalous TET of COT and other molecules, a new theoretical model based on transition state theory for nonadiabatic processes is proposed here, which makes use of the adiabatic potential energy surfaces (PES) of reactants and products, as computed from high-level quantum mechanical methods, and a nonadiabatic transfer rate constant. It is shown that the rate of transfer depends on a geometrical distortion parameter γ = (2g2/κ1)1/2 in which g stands for the norm of the energy gradient in the PES of the acceptor triplet state and κ1 is a combination of vibrational force constants of the ground-state acceptor in the gradient direction. The application of the model to existing experimental data for the triplet energy transfer reaction to COT from a series of π,π∗ triplet donors, provides a detailed interpretation of the parameters that determine the transfer rate constant. In addition, the model shows that the observed decrease of the acceptor electronic excitation energy is due to thermal activation of C�C bond stretchings and C–C bond torsions, which collectively change the ground-state COT bent conformation (D2d) toward a planar triplet state (D8h)[email protected]

Comparison of Row Cover Systems for Pest Management in Organic Muskmelon in Iowa

Organic growers of cucurbit (Cucurbitaceae) crops in the midwestern United States have difficulty managing bacterial wilt—a fatal disease with a pathogen (Erwinia tracheiphila) that is transmitted by striped and spotted cucumber beetles (Acalymma vittatum and Diabrotica undecimpunctata howardi, respectively). Registered organic insecticides lack effectiveness, and host plant resistance is rare in commercial cultivars of many cucurbit crops. Row covers are widely used as barriers to minimize pest access, but the spunbonded polypropylene fabric covering traditional low tunnels must be removed at bloom to prevent overheating and facilitate pollination, thereby exposing the crop for the rest of the season. “Mesotunnels”—nylon mesh fabric covering 3.5-ft-high hoops—provide more space than low tunnels and mitigate overheating. In field experiments at Iowa State University (Ames, IA, USA) during 2016–18, two variations of mesotunnels—full-season tunnels [with purchased bumble bees (Bombus impatiens) added for pollination] and part-season tunnels (with covers removed for 2 weeks during bloom to provide pollinator access)—were compared with low tunnels and a noncovered treatment for organic ‘Athena’ muskmelon (Cucumis melo) production. Based on scouting results, full-season mesotunnels required no insecticides and part-season mesotunnels averaged 0.6 spray per season compared with 1.0 and 5.0 sprays per season for the low-tunnel and noncovered treatments, respectively. Incidence of pest and disease damage was zero for the full-season mesotunnels, 5% to 22% for the part-season mesotunnels, and 37% to 70% for both of the other treatments. Marketable yield for the full-season mesotunnel treatment exceeded the noncovered treatment significantly each year, and mean marketable yields were greater numerically than for the other treatments. Both mesotunnel treatments had a marketable yield that averaged more than twice that of the noncovered treatment in each year. Economic analysis (partial budget and cost-efficiency ratio) indicated that mesotunnels were likely to be more profitable in Iowa, USA, than either the low-tunnel or noncovered systems, but also that the year-to-year differential among treatments in profitability could be substantial. Additional experiments are needed to evaluate the efficacy of these integrated pest management practices and their profitability at spatial scales representative of commercial farms

Persistence of COVID-19 Symptoms after Recovery in Mexican Population

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease (COVID-19), a highly contagious infectious disease that has caused many deaths worldwide. Despite global efforts, it continues to cause great losses, and leaving multiple unknowns that we must resolve in order to face the pandemic more effectively. One of the questions that has arisen recently is what happens, after recovering from COVID-19. For this reason, the objective of this study is to identify the risk of presenting persistent symptoms in recovered from COVID-19. This case-control study was conducted in one state of Mexico. Initially the data were obtained from the participants, through a questionnaire about symptoms that they had at the moment of the interview. Initially were captured the collected data, to make a dataset. After the pre-processed using the R project tool to eliminate outliers or missing data. Obtained finally a total of 219 participants, 141 recovered and 78 controls. It was used confidence level of 90% and a margin of error of 7%. From results it was obtained that all symptoms have an associated risk in those recovered. The relative risk of the selected symptoms in the recovered patients goes from 3 to 22 times, being infinite for the case of dyspnea, due to the fact that there is no control that presents this symptom at the moment of the interview, followed by the nausea and the anosmia with a RR of 8.5. Therefore, public health strategies must be rethought, to treat or rehabilitate, avoiding chronic problems in patients recovered from COVID-19

Disentangling signatures of selection before and after European colonization in latin Americans

Throughout human evolutionary history, large-scale migrations have led to intermixing (i.e., admixture) between previously separated human groups. Although classical and recent work have shown that studying admixture can yield novel historical insights, the extent to which this process contributed to adaptation remains underexplored. Here, we introduce a novel statistical model, specific to admixed populations, that identifies loci under selection while determining whether the selection likely occurred post-admixture or prior to admixture in one of the ancestral source populations. Through extensive simulations, we show that this method is able to detect selection, even in recently formed admixed populations, and to accurately differentiate between selection occurring in the ancestral or admixed population. We apply this method to genome-wide SNP data of ∼4,000 individuals in five admixed Latin American cohorts from Brazil, Chile, Colombia, Mexico, and Peru. Our approach replicates previous reports of selection in the human leukocyte antigen region that are consistent with selection post-admixture. We also report novel signals of selection in genomic regions spanning 47 genes, reinforcing many of these signals with an alternative, commonly used local-ancestry-inference approach. These signals include several genes involved in immunity, which may reflect responses to endemic pathogens of the Americas and to the challenge of infectious disease brought by European contact. In addition, some of the strongest signals inferred to be under selection in the Native American ancestral groups of modern Latin Americans overlap with genes implicated in energy metabolism phenotypes, plausibly reflecting adaptations to novel dietary sources available in the Americas