Autocueillette durable et sécuritaire de moules bleues du Saint-Laurent en collaboration avec les Wolastoqiyik Wahsipekuk (Québec, Canada)

Les membres de la Première Nation Wolastoqiyik Wahsipekuk basée à Cacouna aimeraient pouvoir cueillir et consommer les moules bleues présentes en abondance sur les rives de l’estuaire du Saint-Laurent dans leur territoire ancestral. Cependant, les lois fédérales communiquées par des affiches de Pêches et Océans Canada en interdisent la cueillette. Un projet pilote a alors été créé entre la Première Nation et le collectif Manger notre Saint-Laurent pour les accompagner dans la réouverture d’un secteur d’autocueillette de moules bleues de manière durable et sécuritaire. Les objectifs étaient d’identifier les enjeux associés à la cueillette de moules dans la documentation scientifique et de co-développer un arbre décisionnel permettant de guider la Première Nation dans l’éventuelle réouverture d’un secteur coquillier. Selon les résultats, la cueillette de moules peut être compromise par des enjeux de conservation de la ressource et/ou de salubrité. Pour que la cueillette soit durable et sécuritaire, il importe de valider que la ressource soit assez abondante et productive (biomasse, densité, taux de productivité) pour assurer la durabilité de la ressource malgré la cueillette, de vérifier la proximité de certaines installations humaines pour réduire les risques de contamination, puis de surveiller certains contaminants (coliformes fécaux, biotoxines marines) pour assurer la sécurité de la cueillette. Une fois ces étapes complétées, un secteur peut être ouvert à la cueillette en communiquant les règlements et les bonnes pratiques de l’autocueillette (taille minimale de cueillette, quotas quotidiens, etc.) pour contribuer à la durabilité de l’autocueillette. Lorsque l’autocueillette de moules bleues est pratiquée de manière durable et sécuritaire, elle permet de rapprocher les membres des communautés des ressources alimentaires du fleuve Saint-Laurent (province de Québec, Canada).The members of the Wolastoqiyik Wahsipekuk First Nation based in Cacouna would like to be able to harvest and consume the blue mussels that are abundant on the shores of the St. Lawrence Estuary in their ancestral territory. However, federal laws communicated by Fisheries and Oceans Canada posters prohibit their harvesting. A pilot project was therefore created between the First Nation and the collective Manger notre Saint-Laurent to help them reopen a blue mussel harvesting area in a sustainable and safe manner. The objectives were to identify the issues associated with mussel harvesting in the scientific documentation and to co-develop a decision tree to guide the First Nation in the eventual reopening of a shellfish harvesting area. Depending on the results, mussel harvesting may be compromised by resource conservation and/or safety issues. For harvesting to be sustainable and safe, it is important to validate that the resource is sufficiently abundant and productive (biomass, density, productivity rate) to ensure the sustainability of the resource despite harvesting, to verify the proximity of certain human facilities to reduce the risks of contamination, and to monitor certain contaminants (fecal coliforms, marine biotoxins) to ensure the safety of the harvest. Once these steps have been completed, an area can be opened up for harvesting by communicating regulations and good harvesting practices (minimum pick size, daily quotas, etc.) to contribute to the sustainability of harvesting. When blue mussel harvesting is practiced in a sustainable and safe manner, it brings community members closer to the food resources of the St. Lawrence River (Province of Quebec, Canada)

Autocueillette durable et sécuritaire de moules bleues du Saint-Laurent en collaboration avec les Wolastoqiyik Wahsipekuk (Québec, Canada)

The members of the Wolastoqiyik Wahsipekuk First Nation based in Cacouna would like to be able to harvest and consume the blue mussels that are abundant on the shores of the St. Lawrence Estuary in their ancestral territory. However, federal laws communicated by Fisheries and Oceans Canada posters prohibit their harvesting. A pilot project was therefore created between the First Nation and the collective Manger notre Saint-Laurent to help them reopen a blue mussel harvesting area in a sustainable and safe manner. The objectives were to identify the issues associated with mussel harvesting in the scientific documentation and to co-develop a decision tree to guide the First Nation in the eventual reopening of a shellfish harvesting area. Depending on the results, mussel harvesting may be compromised by resource conservation and/or safety issues. For harvesting to be sustainable and safe, it is important to validate that the resource is sufficiently abundant and productive (biomass, density, productivity rate) to ensure the sustainability of the resource despite harvesting, to verify the proximity of certain human facilities to reduce the risks of contamination, and to monitor certain contaminants (fecal coliforms, marine biotoxins) to ensure the safety of the harvest. Once these steps have been completed, an area can be opened up for harvesting by communicating regulations and good harvesting practices (minimum pick size, daily quotas, etc.) to contribute to the sustainability of harvesting. When blue mussel harvesting is practiced in a sustainable and safe manner, it brings community members closer to the food resources of the St. Lawrence River (Province of Quebec, Canada)

Fractal organization of the human T cell repertoire in health and after stem cell transplantation.

T cell repertoire diversity is generated in part by recombination of variable (V), diversity (D), and joining (J) segments in the T cell receptor β (TCR) locus. T cell clonal frequency distribution determined by high-throughput sequencing of TCR β in 10 stem cell transplantation (SCT) donors revealed a fractal, self-similar frequency distribution of unique TCR bearing clones with respect to V, D, and J segment usage in the T cell repertoire of these individuals. Further, ranking of T cell clones by frequency of gene segment usage in the observed sequences revealed an ordered distribution of dominant clones conforming to a power law, with a fractal dimension of 1.6 and 1.8 in TCR β DJ and VDJ containing clones in healthy stem cell donors. This self-similar distribution was perturbed in the recipients after SCT, with patients demonstrating a lower level of complexity in their TCR repertoire at day 100 followed by a modest improvement by 1 year post-SCT. A large shift was observed in the frequency distribution of the dominant T cell clones compared to the donor, with fewer than one third of the VDJ-containing clones shared in the top 4 ranks. In conclusion, the normal T cell repertoire is highly ordered with a TCR gene segment usage that results in a fractal self-similar motif of pattern repetition across levels of organization. Fractal analysis of high-throughput TCR β sequencing data provides a comprehensive measure of immune reconstitution after SCT

Fractal organization of the human T cell repertoire in health and after stem cell transplantation.

T cell repertoire diversity is generated in part by recombination of variable (V), diversity (D), and joining (J) segments in the T cell receptor β (TCR) locus. T cell clonal frequency distribution determined by high-throughput sequencing of TCR β in 10 stem cell transplantation (SCT) donors revealed a fractal, self-similar frequency distribution of unique TCR bearing clones with respect to V, D, and J segment usage in the T cell repertoire of these individuals. Further, ranking of T cell clones by frequency of gene segment usage in the observed sequences revealed an ordered distribution of dominant clones conforming to a power law, with a fractal dimension of 1.6 and 1.8 in TCR β DJ and VDJ containing clones in healthy stem cell donors. This self-similar distribution was perturbed in the recipients after SCT, with patients demonstrating a lower level of complexity in their TCR repertoire at day 100 followed by a modest improvement by 1 year post-SCT. A large shift was observed in the frequency distribution of the dominant T cell clones compared to the donor, with fewer than one third of the VDJ-containing clones shared in the top 4 ranks. In conclusion, the normal T cell repertoire is highly ordered with a TCR gene segment usage that results in a fractal self-similar motif of pattern repetition across levels of organization. Fractal analysis of high-throughput TCR β sequencing data provides a comprehensive measure of immune reconstitution after SCT

Tracking the fate and origin of clinically relevant adoptively transferred CD8 +

Adoptively transferred tumor-specific cells can mediate tumor regression in cancers refractory to conventional therapy. Autologous polyclonal tumor-specific cytotoxic T cells (CTL) generated from peripheral blood and infused into patients with metastatic melanoma show enhanced persistence, compared to equivalent numbers of more extensively expanded monoclonal CTL, and are associated with complete remissions (CR) in select patients. We applied high-throughput T cell receptor Vβ sequencing (HTTCS) to identify individual clonotypes within CTL products, track them in vivo post-infusion and then deduce the pre-adoptive transfer (endogenous) frequencies of cells ultimately responsible for tumor regression. The summed in vivo post-transfer frequencies of the top 25 HTTCS-defined clonotypes originally detected in the infused CTL population were comparable to enumeration by binding of antigen peptide-HLA multimers, revealing quantitative HTTCS is a reliable, multimer-independent alternative. Surprisingly, the polyclonal CTL products were composed predominantly of clonotypes that were of very low frequency (VLF) in the endogenous samples, often below the limit of HTTCS detection (0.001%). In patients who achieved durable CRs, the composition of transferred CTLs was dominated (57–90%) by cells derived from a single VLF clonotype. Thus, HTTCS now reveals that tumor-specific CTL enabling long-term tumor control originate from endogenous VLF populations that exhibit proliferative/survival advantages. Along with results indicating that naïve cell populations are most likely to contain cells that exist at VLF within the repertoire, our results provide a strong rationale for favoring T cells arising from VLF populations and with early-differentiation phenotypes when selecting subset populations for adoptive transfer