Simultaneous Effect of Temperature and Irradiance on Growth and Okadaic Acid Production from the Marine Dinoflagellate Prorocentrum belizeanum

Benthic marine dioflagellate microalgae belonging to the genus Prorocentrum are a major source of okadaic acid (OA), OA analogues and polyketides. However, dinoflagellates produce these valuable toxins and bioactives in tiny quantities, and they grow slowly compared to other commercially used microalgae. This hinders evaluation in possible large-scale applications. The careful selection of producer species is therefore crucial for success in a hypothetical scale-up of culture, as are appropriate environmental conditions for optimal growth. A clone of the marine toxic dinoflagellate P. belizeanum was studied in vitro to evaluate its capacities to grow and produce OA as an indicator of general polyketide toxin production under the simultaneous influence of temperature (T) and irradiance (I0). Three temperatures and four irradiance levels were tested (18, 25 and 28 °C; 20, 40, 80 and 120 µE·m−2·s−1), and the response variables measured were concentration of cells, maximum photochemical yield of photosystem II (PSII), pigments and OA. Experiments were conducted in T-flasks, since their parallelepipedal geometry proved ideal to ensure optically thin cultures, which are essential for reliable modeling of growth-irradiance curves. The net maximum specific growth rate (µm) was 0.204 day−1 at 25 °C and 40 µE·m−2·s−1. Photo-inhibition was observed at I0 > 40 μEm−2s−1, leading to culture death at 120 µE·m−2·s−1 and 28 °C. Cells at I0 ≥ 80 µE·m−2·s−1 were photoinhibited irrespective of the temperature assayed. A mechanistic model for µm-I0 curves and another empirical model for relating µm-T satisfactorily interpreted the growth kinetics obtained. ANOVA for responses of PSII maximum photochemical yield and pigment profile has demonstrated that P. belizeanum is extremely light sensitive. The pool of photoprotective pigments (diadinoxanthin and dinoxanthin) and peridinin was not able to regulate the excessive light-absorption at high I0-T. OA synthesis in cells was decoupled from optimal growth conditions, as OA overproduction was observed at high temperatures and when both temperature and irradiance were low. T-flask culture observations were consistent with preliminary assays outdoors

Procedimiento para obtener extracto de pulpo, el producto obtenido y su aplicación como suplemento para el cultivo y criopreservación de tejido y de células en suspensión de invertebrados marinos

Número de publicación: ES2261054 A1 (01.11.2006) También publicado como: ES2261054 B1 (16.11.2007) Número de Solicitud: Consulta de Expedientes OEPM (C.E.O.)P200403171 (31.12.2004)Extracto de pulpo como suplemento para el cultivo y criopreservación de tejido y de células en suspensión de invertebrados marinos. La presente invención se refiere a un procedimiento para obtención de un suplemento para el cultivo in vitro y criopreservación de tejido y de células en suspensión de invertebrados marinos a base de extracto acuoso de pulpo homogeneizado y la utilización de dicho suplemento preparación de medios para la criopreservación de células en suspensión y de tejidos de organismos invertebrados marinos.Universidad de Almerí

Modelo mecanístico para el crecimiento de dinoflagelados tóxicos. Caso de Protoceratium reticulatum

[ESP] En este trabajo se presenta un modelo mecanístico para el crecimiento de dinoflagelados. El modelo puede explicar respuestas velocidad de fotosíntesis versus irradiancia bajo limitación simultánea del crecimiento por nitratos, fosfatos, CO2 e irradiancia. El dinoflagelado modelo fue Protoceratium reticulatum, productor de yessotoxinas. Las células fueron cultivadas en T-Flask a diferentes irradiancias. El modelo simuló las siguientes variables de respuesta: concentración celular, biovolumen de la suspensión celular, concentración de macronutrientes e irradiancia promedio en el interior del cultivo.Queremos expresar nuestro agradecimiento al Dr. José M. Franco y Dra. Beatriz Paz, del Centro Oceanográfico de Vigo, y a los Profesores Manuel Norte y J. Javier Fernández, del Instituto Universitario de Bio- Orgánica Antonio González, por su inestimable ayuda en esta tarea del desarrollo de Bioprocesos relacionados con el cultivo masivo de dinoflagelados tóxicos para la producción de toxinas. Esta investigación está siendo financiada por el Ministerio de Educación y Ciencia (AGL2005- 07924-C04-04), España

Ingeniería de Bioprocesos con dinoflagelados. Experiencias preliminares

[ESP] Los dinoflagelados marinos tóxicos son una fuente extraordinaria de toxinas de gran valor, no solo para programas de investigación toxicológica, medioambiental, química y biomédica, sino también para la producción de fármacos de diferente aplicación. Dada la fragilidad celular de estos microorganismos su cultivo masivo necesita la utilización de biorreactores con configuraciones y modos de operación específicos que eliminen o mitiguen el daño celular por exceso de turbulencia. En este trabajo se presenta una estrategia de cultivo basada en la Ingeniería de Bioprocesos para abordar el cultivo masivo de dinoflagelados tóxicos. El dinoflagelado Protoceratium reticulatum fue cultivado en biorreactores tipo tanque agitado con varios modos de operación: discontinuo, fed-batch, semicontinuo y contínuo. Fueron analizadas la producción celular y de biotoxinas.Queremos expresar nuestro agradecimiento al Dr. José M. Franco y Dra. Beatriz Paz, del Centro Oceanográfico de Vigo, y a los Profesores Manuel Norte y J. Javier Fernández, del Instituto Universitario de Bio- Orgánica Antonio González, por su inestimable ayuda en esta tarea del desarrollo de Bioprocesos relacionados con el cultivo masivo de dinoflagelados tóxicos para la producción de toxinas. Esta investigación está siendo financiada por el Ministerio de Educación y Ciencia (AGL2005- 07924-C04-04), España

Estudio de la influencia del contenido de macronutrientes del medio en el crecimiento del dinoflagelado Protoceratium reticulatum

[ESP] Las necesidades metabólicas de las especies a cultivar tienen una gran importancia a la hora de programar el modo de cultivo para optimizar la productividad de los productos de interés. En este trabajo se presentan dos series de experimentos en los que se realiza un estudio de la influencia de la concentración de dos macronutrientes (nitrato y fosfato) en las principales variables de respuesta del cultivo del dinoflagelado Protoceratium reticulatum.Queremos expresar nuestro agradecimiento al Dr. José M. Franco y Dra. Beatriz Paz, del Centro Oceanográfico de Vigo, y a los Profesores Manuel Norte y J. Javier Fernández, del Instituto Universitario de Bio- Orgánica Antonio González, por su inestimable ayuda en esta tarea del desarrollo de Bioprocesos relacionados con el cultivo masivo de dinoflagelados tóxicos para la producción de toxinas. Esta investigación está siendo financiada por el Ministerio de Educación y Ciencia (AGL2005- 07924-C04-04), España

Daño celular por fuerzas de corte en cultivos de dinoflagelados tóxicos

[ESP] La sensibilidad celular a las fuerzas de corte es el principal obstáculo para el cultivo masivo de dinoflagelados tóxicos con fines comerciales. En el presente trabajo se propone un protocolo para determinar umbrales de daño por fuerzas de corte asociadas a turbulencia continua e intermitente en cultivos de dinoflagelados tóxicos. El dinoflagelado modelo ha sido Protoceratium reticulatum. Esta especie ha resultado ser extraordina- riamente frágil, mucho más que otras líneas celulares que hasta ahora eran considerados los más sensibles a fuerzas de corte, como los eritrocitos.Queremos expresar nuestro agradecimiento al Dr. José M. Franco y Dra. Beatriz Paz, del Centro Oceanográfico de Vigo, y a los Profesores Manuel Norte y J. Javier Fernández, del Instituto Universitario de Bio- Orgánica Antonio González, por su inestimable ayuda en esta tarea del desarrollo de Bioprocesos relacionados con el cultivo masivo de dinoflagelados tóxicos para la producción de toxinas. Esta investigación está siendo financiada por el Ministerio de Educación y Ciencia (AGL2005- 07924-C04-04), España

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Bond durability of basalt-fiber-reinforced-polymer (BFRP) bars embedded in concrete in aggressive environments

Recently, basalt-fiber-reinforced-polymer (BFRP) bars have emerged as a promising alternative to glass-fiber-reinforced-polymer (GFRP) bars. So far, however, BFRP bars have not been incorporated into design standards and specifications. This is due to limited studies and lack of knowledge on the performance of the bars in concrete, in particular, their bond durability when exposed to aggressive environments. This paper presents some results of an extensive research program investigating the bond durability behaviors of BFRP bars in concrete structures and the long-term bond-strength-retention predications of the BFRP bars on the basis of short-term tests results. This research included testing deformed BFRP bars measuring 12 mm in diameter. Pullout specimens were tested with direct tensile loading after being exposed to an alkaline solution (pH 12.9) for 1.5, 3, and 6 months at temperatures of 40 °C, 50 °C, and 60 °C. This paper investigated the effects of alkaline environment, exposure periods, and elevated temperatures on bond strength as well as the degradation mechanism and mode of failure of the BFRP-reinforced specimens. In addition, optical microscopy and scanning electronic microscopy were used to investigate the degradation of BFRP bars tested. The test results indicate an initial increase in the bond strength of the conditioned specimens as the temperature increased compared to their unconditioned specimens. After 1.5 months of exposure, the specimens conditioned at 50 °C and 60 °C, respectively, had bond-strength increases of 25% and 26%, while the specimens conditioned at 40 °C exhibited no noticeable changes (a minor decrease of 4.3%). Nevertheless, the bond strength of the conditioned specimens deteriorated during immersion. The highest bond-strength reductions occurred in the conditioned specimens after 6 months of exposure at 40 °C (a 16% loss), followed by specimens conditioned at 50 °C (7% loss) and 60 °C (5% loss) compared to their counterparts at 1.5 months. Lastly, the long-term bond-strength-retention predications of the BFRP bars after 50 years of service life in dry, moist, and moisture-saturated environments with mean annual temperatures between 5 °C and 35 °C ranged from 71% to 92%