Browsing by Author "Ibanez, Francisco"

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    Heterologous production of the epoxycarotenoid violaxanthin in Saccharomyces cerevisiae
    (2020) Cataldo, Vicente F.; Arenas, Natalia; Salgado, Valeria; Camilo, Conrado; Ibanez, Francisco; Agosin, Eduardo
    Microbial production of carotenoids has mainly focused towards a few products, such as beta-carotene, lycopene and astaxanthin. However, other less explored carotenoids, like violaxanthin, have also shown unique properties and promissory applications. Violaxanthin is a plant-derived epoxidated carotenoid with strong antioxidant activity and a key precursor of valuable compounds, such as fucoxanthin and beta-damascenone. In this study, we report for the first time the heterologous production of epoxycarotenoids in yeast. We engineered the yeast Saccharomyces cerevisiae following multi-level strategies for the efficient accumulation of violaxanthin. Starting from a beta-carotenogenic yeast strain, we first evaluated the performance of several beta-carotene hydroxylases (CrtZ), and zeaxanthin epoxidases (ZEP) from different species, together with their respective N-terminal truncated variants. The combined expression of CrtZ from Pantoea ananatis and truncated ZEP of Haematococcus lacustris showed the best performance and led to a yield of 1.6 mg/g(DCW) of violaxanthin. Further improvement of the epoxidase activity was achieved by promoting the transfer of reducing equivalents to ZEP by expressing several redox partner systems. The co-expression of the plant truncated ferredoxin-3, and truncated root ferredoxin oxidoreductase-1 resulted in a 2.2-fold increase in violaxanthin yield (3.2 mg/g(DCW)). Finally, increasing gene copy number of carotenogenic genes enabled reaching a final production of 7.3 mg/g(DCW) in shake flask cultures and batch bioreactors, which is the highest yield of microbially produced violaxanthin reported to date.
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    Robust control of fed-batch high-cell density cultures: a simulation-based assessment
    (2021) Ibanez, Francisco; Saa, Pedro A.; Bárzaga Martell, Lisbel; Duarte-Mermoud, Manuel A.; Fernandez-Fernandez, Mario; Agosin, Eduardo; Perez Correa, Jose Ricardo
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    The impact of SARS-CoV-2 in dementia across Latin America: A call for an urgent regional plan and coordinated response
    (2020) Ibanez, Agustin; Santamaria-Garcia, Hernando; Guerrero Barragan, Alejandra; Kornhuber, Alexander; Marques Ton, Alyne Mendonca; Slachevsky, Andrea; Lucio Teixeira, Antonio; Mar Meza, Beatriz Marcela; Serrano, Cecilia M.; Cano, Carlos; Arias Gonzalez, Carolina; Gonzalez-Billault, Christian; Butler, Christopher; Bustin, Julian; Duran-Aniotz, Claudia; Acosta, Daisy; Matallana, Diana L.; Acosta-Alvear, Diego; Trepel, Dominic; Franca Resende, Elisa De Paula; Ferreira Oliveira, Fabricio; Ibanez, Francisco; De Felice, Fernanda G.; Navarrete, Gorka; Tarnanas, Ioannis; Meier, Irene B.; Smid, Jerusa; Llibre-Guerra, Jorge; Llibre-Rodriguez, Juan J.; Fajersztajn, Lais; Takada, Leonel Tadao; Duque, Lissette; de Oliveira, Maira Okada; Camargos Bicalho, Maria Aparecida; Isabel Behrens, Maria; Pintado-Caipa, Maritza; Parra, Mario; Wilson, Maxwell Z.; De la Cruz Puebla, Myriam; Custodio, Nilton; Santibanez, Rodrigo; Serafim, Rodrigo Bernardo; Tavares, Ronnielly Melo; Pina Escudero, Stefanie Danielle; Leon Rodriguez, Tomas; Dawson, Walter; Miller, Bruce L.; Kosik, Kenneth S.
    The SARS-CoV-2 global pandemic will disproportionately impact countries with weak economies and vulnerable populations including people with dementia. Latin American and Caribbean countries (LACs) are burdened with unstable economic development, fragile health systems, massive economic disparities, and a high prevalence of dementia. Here, we underscore the selective impact of SARS-CoV-2 on dementia among LACs, the specific strain on health systems devoted to dementia, and the subsequent effect of increasing inequalities among those with dementia in the region. Implementation of best practices for mitigation and containment faces particularly steep challenges in LACs. Based upon our consideration of these issues, we urgently call for a coordinated action plan, including the development of inexpensive mass testing and multilevel regional coordination for dementia care and related actions. Brain health diplomacy should lead to a shared and escalated response across the region, coordinating leadership, and triangulation between governments and international multilateral networks.