IGG3 Subclass Antibodies Recognize Antigenically Drifted Influenza Viruses and SARS-CoV-2 Variants Through Efficient Bivalent Binding

The constant domains of antibodies are important for effector functions, but less is known about how they can affect binding and neutralization of viruses. Here, we evaluated a panel of human influenza virus monoclonal antibodies (mAbs) expressed as IgG1, IgG2, or IgG3. We found that many influenza virus-specific mAbs have altered binding and neutralization capacity depending on the IgG subclass encoded and that these differences result from unique bivalency capacities of the subclasses. Importantly, subclass differences in antibody binding and neutralization were greatest when the affinity for the target antigen was reduced through antigenic mismatch. We found that antibodies expressed as IgG3 bound and neutralized antigenically drifted influenza viruses more effectively. We obtained similar results using a panel of SARS-CoV-2-specific mAbs and the antigenically advanced B.1.351 and BA.1 strains of SARS-CoV-2. We found that a licensed therapeutic mAb retained neutralization breadth against SARS-CoV-2 variants when expressed as IgG3, but not IgG1. These data highlight that IgG subclasses are not only important for fine-tuning effector functionality but also for binding and neutralization of antigenically drifted viruses

A two-plasmid strategy for engineering a dengue virus type 3 infectious clone from primary Brazilian isolate

Dengue infections represent one of the most prevalent arthropod-borne diseases worldwide, causing a wide spectrum of clinical outcomes. Engineered infectious clone is an important tool to study Dengue virus (DENV) biology. Functional full-length cDNA clones have been constructed for many positive-strand RNA viruses and have provided valuable tools for studying the molecular mechanisms involved in viral genome replication, virion assembly, virus pathogenesis and vaccine development. We report herein the successful development of an infectious clone from a primary Brazilian isolate of dengue virus 3 (DENV3) of the genotype III. Using a two-plasmid strategy, DENV3 genome was divided in two parts and cloned separately into a yeast-bacteria shuttle vector. All plasmids were assembled in yeast by homologous recombination technique and a full-length template for transcription was obtained by in vitro ligation of the two parts of the genome. Transcript-derived DENV3 is infectious upon transfection into BHK-21 cells and in vitro characterization confirmed its identity. Growth kinetics of transcript-derived DENV3 was indistinguishable from wild type DENV3. This system is a powerful tool that will help shed light on molecular features of DENV biology, as the relationship of specific mutations and DENV pathogenesis

Conhecimento tradicional das marisqueiras de Barra Grande, área de proteção ambiental do delta do Rio Parnaíba, Piauí, Brasil

Na comunidade de Barra Grande localizada no litoral do Piauí, as mulheres dos pescadores, conhecidas localmente como marisqueiras, extraem do manguezal vários tipos de moluscos para comercialização e em maior escala para a subsistência. Dados sobre a atividade de mariscagem, conceitos de conservação e aspectos socioeconômicos do contexto em que ocorre a atividade de cata dos moluscos, foram revelados após a aplicação de protocolos estruturados e semiestruturados. O molusco bivalve Anomalocardia brasiliana (Gmelin, 1791), popularmente denominado de marisco, é caracterizado por ser um importante recurso para a subsistência, sendo o mais coletado pela comunidade, seguido da Mytella charruana (d'Orbigny, 1842), o sururu, explorado para a comercialização por ter o maior valor de mercado. O conhecimento das marisqueiras sobre A. brasiliana foi comparado com literatura especializada, muitas vezes mostrando-se em harmonia com esta. Demonstra-se assim que o conhecimento tradicional deve ser valorizado para delineamento de programas de gestão de recursos pesqueiros da região. Quanto aos modos de pensar, foi revelado que 82,81% das marisqueiras praticam manejo para a conservação da A. brasiliana ao coletar apenas os indivíduos de maior tamanho, e 80,86% consideram que não existe poluição nos pontos de coletas. O surgimento de uma Associação exclusiva e cooperativa para as marisqueiras é necessário para a valorização do trabalho por elas desenvolvido, visto que há uma média estimada de 351 kg de carne sendo extraídos mensalmente.<br>En la comunidad de Barra Grande, situada en la costa del estado de Piaui, las esposas de los pescadores, localmente llamadas de "marisqueiras", extraen de los manglares diversos tipos de moluscos para su comercialización, haciendo de esta actividad en una fuente de subsistencia. Informaciones detalladas y sistemáticas sobre la actividad de cosecha de mariscos, del contexto en el que se desarrolla la recolección y sus aspectos socioeconómicos, asi como la percepción ambiental y los conceptos relacionados a la preservación que tienen las "marisqueiras", sólo fueron conocidas luego de la aplicación de protocolos estructurados y semi-estructurados. El molusco Anomalocardia brasiliana (Gmelin, 1791), popularmente conocido como "marisco", es una importante fuente de recursos, siendo el más cosechado por la comunidad; le sigue en importancia el Mytella charruana (d'Orbigny, 1842), conocido como "sururu", cuya explotación se destina principalmente a la comercialización debido a su superior valor de mercado. El conocimiento que las "marisqueiras" tienen de la A. brasiliana fue comparado con el disponible en la literatura especializada, quedando evidente su compatibilidad, lo cual fundamenta la importancia de su valorización en el diseño de programas de gestión de los recursos pesqueros en la región. Estudios sobre el impacto ambiental de la actividad revelaron que el 82,81% de las "marisqueiras" tienen en cuenta las consecuencias de su actividad sobre la preservación, cosechando sólo los ejemplares más grandes, mientras que 80,86% de las trabajadoras considera que no hay contaminación en las zonas de cosecha. En el contexto actual se hace necesaria la creación de una Asociación de "marisqueiras", así como una cooperativa, con el propósito de jerarquizar la actividad, la cual es responsable por la producción estimada en promedio de 351 kg de carne por mes.<br>In the community of Barra Grande located at the coast of Piauí, the wives of fishermen, locally known as "marisqueiras" (female shellfish catcher), extract from the mangrove various kinds of shellfish for commercial purposes and a great amount for subsistence. For a better understanding, data on the activity of "marisqueiras", concepts of conservation and socioeconomic aspects of the context in which occurs the activity of shellfish catching were revealed after the application of semi-structured and structured protocols. The bivalve mussel Anomalocardia brasiliana (Gmelin, 1791), popularly known as "marisco", is characterized as an important resource for subsistence being most of it collected by the community, followed by Mytella charruana (d'Orbigny, 1842) the "sururu", extract for commercial purposes due to its highest market value. The knowledge of the "marisqueiras" about A. brasiliana was compared with literature which proved to be compatible, thus showing that it should be valued for the design of programs for the management of fishing resources in the region. About the way of thinking, it was revealed that 82.81% of "marisqueiras" practice the conservation of the A. brasiliana by collecting only the larger individuals and 80.86% consider that there is no pollution at the collection points. The creation of a unique association and a cooperative for the "marisqueiras" is required to value the work by themselves developed, since there are an estimated average of 351 kg of meat being extracted monthly

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora