Performance analysis of existing catfish and tilapia value chains and market systems in Nigeria: A post-farmgate value chain scoping study

Nigeria is the largest fish producer in Sub-Saharan Africa. Fish plays a crucial role in supporting the livelihoods of fish producers and actors along the post-farmgate value chain in the country. Despite the virtues of the aquaculture and fisheries subsectors to enhance the livelihoods of value chain actors, major gaps exist related to efficiencies of the fish value chain. These gaps include the financial performance of post-farmgate actors, gender-disaggregated data on value chain actors, the roles of women and youths in fish trade, and post-farmgate food safety practices. The aim of this study is to fill the data gap in the post-farmgate fish value chain to provide evidence-based policy suggestions to enhance the aquaculture subsector in Nigeria. Using primary data, our study provides evidence on the economic, environmental, social, nutritional and food safety performance of the post-farmgate fish value chain. Our study finds that, in general, fish value chains are economically viable (profitable) and inclusive, as women and youths own over half of post-farmgate value chain activities. These results are of interest to both private and public sector decision-makers and policymakers because they provide quantitative data on value creation (fish sales, employment, service provision), social performance (women and youth empowerment), and environmental, nutritional and food safety challenges along fish value chains

Insights into the Mechanism and Catalysis of Peptide Thioester Synthesis by Alkylselenols Provide a New Tool for Chemical Protein Synthesis

Posté sur ChemRxiv le 2021-02-11.While thiol-based catalysts are widely employed for chemical protein synthesis relying on peptide thioester chemistry, this is less true for selenol-based catalysts whose development is in its infancy. In this study, we compared different selenols derived from the selenocysteamine scaffold for their capacity to promote thiol-thioester exchanges in water at mildly acidic pH and the production of peptide thioesters from bis(2-sulfanylethyl)amido (SEA) peptides. The usefulness of a selected selenol compound is illustrated by the total synthesis of a biologically active human chemotactic protein, which plays an important role in innate and adaptive immunit

Insights into the Mechanism and Catalysis of Peptide Thioester Synthesis by Alkylselenols Provide a New Tool for Chemical Protein Synthesis

While thiol-based catalysts are widely employed for chemical protein synthesis relying on peptide thioester chemistry, this is less true for selenol-based catalysts whose development is in its infancy. In this study, we compared different selenols derived from the selenocysteamine scaffold for their capacity to promote thiol-thioester exchanges in water at mildly acidic pH and the production of peptide thioesters from bis(2-sulfanylethyl)amido (SEA) peptides. The usefulness of a selected selenol compound is illustrated by the total synthesis of a biologically active human chemotactic protein, which plays an important role in innate and adaptive immunity<br /

Role of T CD4+ cells, macrophages, C‐LTMRs and spinal‐located Ca v 3.2 calcium channels in inflammation and related pain‐like symptoms in murine inflammatory models

International audienceBackground and purpose: T-type calcium channels, mainly the Cav 3.2 subtype, are important contributors to the nociceptive signaling pathway. We investigated their involvement in inflammation and related pain-like symptoms.Experimental approach: The involvement of Cav 3.2 and T-type channels was investigated using genetic and pharmacological inhibition to assess mechanical allodynia/hyperalgesia and edema development in two murine inflammatory pain models. The location of Cav 3.2 involved in pain-like symptoms was studied in mice with Cav 3.2 knocked out in C-low threshold mechanoreceptors (C-LTMR) and the use of ABT-639, a peripherally restricted T-type channel inhibitor. The anti-edematous effect of Cav 3.2 inhibition was investigated in chimeric mice with immune cells deleted for Cav 3.2. Lymphocytes and macrophages from either green fluorescent protein-targeted Cav 3.2 or KO mice were used to determine the expression of Cav 3.2 protein and the functional status of the cells.Key results: We showed the role of Cav 3.2 channels in the development of pain-like symptoms and edema in the two murine inflammatory pain models. For the first time, we provide evidence of the involvement of Cav 3.2 channels located on C-LTMRs and spinal cord in inflammatory pain. We showed that Cav 3.2 channels located in T cells and macrophages contribute to the inflammatory process.Conclusion and implications: This work highlights the crucial role of Cav 3.2 channels in inflammation and related pain and suggests that targeting Cav 3.2 channels with pharmacological agents could be an attractive and readily evaluable strategy in a clinical trial to relieve chronic inflammatory pain in affected patients

L'infection par le SARS-CoV-2 induit des lésions persistantes du tissu adipeux chez les hamsters syriens dorés âgés.

International audienceCoronavirus disease 2019 (COVID-19, caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2)) is primarily a respiratory illness. However, various extrapulmonary manifestations have been reported in patients with severe forms of COVID-19. Notably, SARS-CoV-2 was shown to directly trigger white adipose tissue (WAT) dysfunction, which in turn drives insulin resistance, dyslipidemia, and other adverse outcomes in patients with COVID-19. Although advanced age is the greatest risk factor for COVID-19 severity, published data on the impact of SARS-CoV-2 infection on WAT in aged individuals are scarce. Here, we characterized the response of subcutaneous and visceral WAT depots to SARS-CoV-2 infection in young adult and aged golden hamsters. In both age groups, infection was associated with a decrease in adipocyte size in the two WAT depots; this effect was partly due to changes in tissue’s lipid metabolism and persisted for longer in aged hamsters than in young-adult hamsters. In contrast, only the subcutaneous WAT depot contained crown-like structures (CLSs) in which dead adipocytes were surrounded by SARS-CoV-2-infected macrophages, some of them forming syncytial multinucleated cells. Importantly, older age predisposed to a unique manifestation of viral disease in the subcutaneous WAT depot during SARS-CoV-2 infection; the persistence of very large CLSs was indicative of an age-associated defect in the clearance of dead adipocytes by macrophages. Moreover, we uncovered age-related differences in plasma lipid profiles during SARS-CoV-2 infection. These data suggest that the WAT’s abnormal response to SARS-CoV-2 infection may contribute to the greater severity of COVID-19 observed in elderly patients.La maladie à coronavirus 2019 (COVID-19, causée par le syndrome respiratoire aigu sévère-coronavirus 2 (SRAS-CoV-2)) est principalement une maladie respiratoire. Cependant, diverses manifestations extrapulmonaires ont été signalées chez des patients atteints de formes graves de COVID-19. Il a notamment été démontré que le SRAS-CoV-2 déclenche directement le dysfonctionnement du tissu adipeux blanc (TAC), qui entraîne à son tour une résistance à l'insuline, une dyslipidémie et d'autres effets indésirables chez les patients atteints de COVID-19. Bien que l'âge avancé soit le facteur de risque le plus important pour la gravité de la COVID-19, les données publiées sur l'impact de l'infection par le SRAS-CoV-2 sur le tissu adipeux des personnes âgées sont rares. Nous avons caractérisé ici la réponse des dépôts de WAT sous-cutanés et viscéraux à l'infection par le SRAS-CoV-2 chez des hamsters dorés jeunes adultes et âgés. Dans les deux groupes d'âge, l'infection a été associée à une diminution de la taille des adipocytes dans les deux dépôts de WAT ; cet effet était en partie dû à des changements dans le métabolisme des lipides du tissu et a persisté plus longtemps chez les hamsters âgés que chez les jeunes adultes. En revanche, seul le dépôt de WAT sous-cutané contenait des structures en forme de couronne (CLS) dans lesquelles les adipocytes morts étaient entourés de macrophages infectés par le SRAS-CoV-2, certains d'entre eux formant des cellules syncytiales multinucléées. Il est important de noter que l'âge avancé prédisposait à une manifestation unique de la maladie virale dans le dépôt sous-cutané de WAT pendant l'infection par le SRAS-CoV-2 ; la persistance de très grandes CLSs indiquait un défaut associé à l'âge dans l'élimination des adipocytes morts par les macrophages. De plus, nous avons mis en évidence des différences liées à l'âge dans les profils lipidiques plasmatiques au cours de l'infection par le SRAS-CoV-2. Ces données suggèrent que la réponse anormale du WAT à l'infection par le SRAS-CoV-2 peut contribuer à la plus grande sévérité du COVID-19 observée chez les patients âgés

High Dimensional Single-Cell Analysis Reveals iNKT Cell Developmental Trajectories and Effector Fate Decision

International audienceCD1d-restricted invariant Natural Killer T (iNKT) cells represent a unique class of T lymphocytes endowed with potent regulatory and effector immune functions. Although these functions are acquired during thymic ontogeny, the sequence of events that gives rise to discrete effector subsets remains unclear. Using an unbiased single-cell transcriptomic analysis combined with functional assays, we reveal an unappreciated diversity among thymic iNKT cells, especially among iNKT1 cells. Mathematical modeling and biological methods unravel a developmental map whereby iNKT2 cells constitute a transient branching point toward the generation of iNKT1 and iNKT17 cells, which reconciles the two previously proposed models. In addition, we identify the transcription co-factor Four-and-a-half LIM domains protein 2 (FHL2) as a critical cell-intrinsic regulator of iNKT1 specification. Thus, these data illustrate the changing transcriptional network that guides iNKT cell effector fate

Diet-Induced Obesity and NASH Impair Disease Recovery in SARS-CoV-2-Infected Golden Hamsters

International audienceObese patients with non-alcoholic steatohepatitis (NASH) are prone to severe forms of COVID-19. There is an urgent need for new treatments that lower the severity of COVID-19 in this vulnerable population. To better replicate the human context, we set up a diet-induced model of obesity associated with dyslipidemia and NASH in the golden hamster (known to be a relevant preclinical model of COVID-19). A 20-week, free-choice diet induces obesity, dyslipidemia, and NASH (liver inflammation and fibrosis) in golden hamsters. Obese NASH hamsters have higher blood and pulmonary levels of inflammatory cytokines. In the early stages of a SARS-CoV-2 infection, the lung viral load and inflammation levels were similar in lean hamsters and obese NASH hamsters. However, obese NASH hamsters showed worse recovery (i.e., less resolution of lung inflammation 10 days post-infection (dpi) and lower body weight recovery on dpi 25). Obese NASH hamsters also exhibited higher levels of pulmonary fibrosis on dpi 25. Unlike lean animals, obese NASH hamsters infected with SARS-CoV-2 presented long-lasting dyslipidemia and systemic inflammation. Relative to lean controls, obese NASH hamsters had lower serum levels of angiotensin-converting enzyme 2 activity and higher serum levels of angiotensin II—a component known to favor inflammation and fibrosis. Even though the SARS-CoV-2 infection resulted in early weight loss and incomplete body weight recovery, obese NASH hamsters showed sustained liver steatosis, inflammation, hepatocyte ballooning, and marked liver fibrosis on dpi 25. We conclude that diet-induced obesity and NASH impair disease recovery in SARS-CoV-2-infected hamsters. This model might be of value for characterizing the pathophysiologic mechanisms of COVID-19 and evaluating the efficacy of treatments for the severe forms of COVID-19 observed in obese patients with NASH