Respuesta a estrés oxidativo generado por alta luz y dióxido de carbono (CO2) en el modelo productor de biodiesel Nannochloropsis salina (Ochrophyta, Eustigmatales)

Indexación: Web of Science; Scielo.Due to overconsumption of fossil fuels, microalgae have arrived as an alternative source of biofuel. Looking forward to generate a sustainable process, it is proposed to couple the cultures to CO2 emission sources, reaching in this way higher biomass performance and helping in the way with the capture of carbon released by the combustion processes. Nannochloropsis salina is a microalgae from the Monodopsidaceae family, which is easy to grow and produces high value compounds like essential pigments, polyunsaturated fatty acids and high amounts of lipids. Previous studies showed that adding CO2 to cultures (until 2%) generated an increment in biomass and in the production of fatty acids. However, these conditions also induce acidification of the media, a condition that may promote the generation of oxygen reactive species. In this work, the antioxidant performance of N. salina was studied under different culture conditions involving CO2 through 3 different approaches: analysis of antioxidant enzymatic activities (catalase, ascorbate peroxidase and peroxiredoxine), analysis of gene expression and the quantification of H2O2, phenolic compounds and lipoperoxides (e.g., cell damage marker). The results obtained suggest that an increase in the CO2 concentration in the cultures (15,000 ppm), together with high light (1,000 µmol m-1 s-1) induces an oxidative stress condition in N. salina cells. However, the antioxidant response observed in the microalgae manages to soften this stress, adapting themselves to these conditions without affecting their global performance.Producto del agotamiento de los recursos mundiales de combustibles fósiles, las microalgas han tomado fuerza como alternativa de biocombustible. Buscando hacer sustentable el proceso, en general se propone realizar los cultivos acoplados a fuentes de emisión de CO2, logrando con ello mayores rendimientos en biomasa y mitigando la huella de carbono de los procesos de combustión. Nannochloropsis salina es una microalga de la familia Monodopsidaceae de fácil crecimiento y que produce compuestos de valor comercial, tales como pigmentos esenciales, ácidos grasos poliinsaturados y alta cantidad de lípidos. Estudios previos muestran que en presencia de algunas concentraciones de CO2 (hasta 2%) se produce un aumento de la biomasa y de la producción de ácidos grasos. Sin embargo, estas condiciones traen consigo una acidificación del medio, condición que afecta la eficiencia del proceso de fotosíntesis y promueve la generación de especies reactivas de oxígeno. En este trabajo, se estudió la respuesta antioxidante de cultivos de Nannochloropsis salina suplementados con CO2, por medio de 3 metodologías: analizando la actividad enzimática antioxidante (catalasa, ascorbato peroxidasa y peroxirredoxina), cuantificando los compuestos fenólicos, H2O2 y lipoperóxidos (i.e., marcador de daño celular) y evaluando los niveles de expresión génica. Los resultados sugieren que un aumento en la concentración de CO2 en el cultivo, junto con alta luz, induce una condición de estrés oxidativo en Nannochloropsis salina. Sin embargo, la respuesta celular observada en esta microalga logra atenuar este estrés, sin afectar su rendimiento global.http://ref.scielo.org/c65md

Metabolismo de metilglioxal en macroalgas durante desecación

Indexación: Scielo; Web of Science.In primary producers, diverse stressors cause an over-production of methylglyoxal (MG), which is principally detoxified by glyoxalase I (GLO1) activity. A recent proteomic study found that GLO1 was up-regulated during natural desiccation in the red seaweed Pyropia orbicularis, which inhabits the upper intertidal rocky zone and compared to other species, is highly tolerant to air exposure. To better understand and determine differential responses to desiccation stress, this study evaluated MG concentration and GLO1 activity in two species with contrasted vertical distribution, P. orbicularis and Lessonia spicata (lower distribution). Results showed that P. orbicularis successfully scavenges MG via increased GLO1 activity during desiccation. In contrast, GLO1 activity in L. spicata did not increase during desiccation, resulting in MG overproduction. This study is the first to quantify MG and GLO1 levels in seaweeds during natural stress, and partly explain the mechanisms by which P. orbicularis is dominant in the upper rocky intertidal zone.http://ref.scielo.org/tp4sn

Enhancement of Xanthophyll Synthesis in Porphyra/Pyropia Species (Rhodophyta, Bangiales) by Controlled Abiotic Factors: A Systematic Review and Meta-Analysis

Indexación: ScopusRed alga species belonging to the Porphyra and Pyropia genera (commonly known as Nori), which are widely consumed and commercialized due to their high nutritional value. These species have a carotenoid profile dominated by xanthophylls, mostly lutein and zeaxanthin, which have relevant benefits for human health. The effects of different abiotic factors on xanthophyll synthesis in these species have been scarcely studied, despite their health benefits. The objectives of this study were (i) to identify the abiotic factors that enhance the synthesis of xanthophylls in Porphyra/Pyropia species by conducting a systematic review and meta-analysis of the xanthophyll content found in the literature, and (ii) to recommend a culture method that would allow a significant accumulation of these compounds in the biomass of these species. The results show that salinity significantly affected the content of total carotenoids and led to higher values under hypersaline conditions (70,247.91 µg/g dm at 55 psu). For lutein and zeaxanthin, the wavelength treatment caused significant differences between the basal and maximum content (4.16-23.47 µg/g dm). Additionally, in Pyropia spp., the total carotenoids were considerably higher than in Porphyra spp.; however, the lutein and zeaxanthin contents were lower. We discuss the specific conditions for each treatment and the relation to the ecological distribution of these species

Ingestion of contaminated kelps by the herbivore Tetrapygus niger: Negative effects on food intake, growth, fertility, and early development

Indexación ScopusMacrocystis pyrifera reaches distant areas after detachment, accumulate heavy metals, and serve as trophic subsidy. In this context, effects on both adults and larvae of Tetrapygus niger fed with polluted kelps were determined by assessing growth, fertility, and early larval development. Results revealed that sea urchins fed with polluted kelps from highly impacted zone (HIZ) showed a lower growth (3.6% gained weight) and gamete release (358 cells mL−1) than those fed with non-impacted kelps (NIZ) (19.3% and 945 cells mL−1). The HIZ treatment showed a developmental delay in comparison to NIZ, accounted mainly by the abundance of malformed 2-arm pluteus larvae (10–15%) during most of the culture. Malformed 4-arm pluteus larvae showed a constant increase, reaching 37% at the end of the culture. Thus, the pollutants ingested by sea urchins can be transferred to their offspring and cause negative effects in their early development, categorizing M. pyrifera as a pollutant carrier. © 2021 The Authorshttps://www-sciencedirect-com.recursosbiblioteca.unab.cl/science/article/pii/S0025326X21003994?via%3Dihu

Proteome analysis reveals extensive light stress-response reprogramming in the seagrass Zostera muelleri (alismatales, zosteraceae) metabolism

© 2017, Kumar, Padula, Davey, Pernice, Jiang, Sablok, Contreras-Porcia and Ralph. Seagrasses are marine ecosystem engineers that are currently declining in abundance at an alarming rate due to both natural and anthropogenic disturbances in ecological niches. Despite reports on the morphological and physiological adaptations of seagrasses to extreme environments, little is known of the molecular mechanisms underlying photo-acclimation, and/or tolerance in these marine plants. This study applies the two-dimensional isoelectric focusing (2D-IEF) proteomics approach to identify photo-acclimation/tolerance proteins in the marine seagrass Zostera muelleri. For this, Z. muelleri was exposed for 10 days in laboratory mesocosms to saturating (control, 200 µmol photons m−2 s−1), super-saturating (SSL, 600 µmol photons m−2 s−1), and limited light (LL, 20 µmol photons m−2 s−1) irradiance conditions. Using LC-MS/MS analysis, 93 and 40 protein spots were differentially regulated under SSL and LL conditions, respectively, when compared to the control. In contrast to the LL condition, Z. muelleri robustly tolerated super-saturation light than control conditions, evidenced by their higher relative maximum electron transport rate and minimum saturating irradiance values. Proteomic analyses revealed up-regulation and/or appearances of proteins belonging to the Calvin-Benson and Krebs cycle, glycolysis, the glycine cleavage system of photorespiration, and the antioxidant system. These proteins, together with those from the inter-connected glutamate-proline-GABA pathway, shaped Z. muelleri photosynthesis andgrowth under SSL conditions. In contrast, the LL condition negatively impacted the metabolic activities of Z. muelleri by down-regulating key metabolic enzymes for photosynthesis and the metabolism of carbohydrates and amino acids, which is consistent with the observation with lower photosynthetic performance under LL condition. This study provides novel insights into the underlying molecular photo-acclimation mechanisms in Z. muelleri, in addition to identifying protein-based biomarkers that could be used as early indicators to detect acute/chronic light stress in seagrasses to monitor seagrass health

Expresión diferencial de genes en Pyropia columbina (Bangiales, Rhodophyta) bajo hidratación y desecación natural

Indexación: Web of Science; Scielo.RESUMEN. En Zonas Costeras rocosas, la desecación es gatillada porción Cambios Diarios en los Niveles de marea, y la Evidencia indica experimental de Me Distribución de las algas en la zona intermareal no está Relacionada estafa do palabra capacidad, párr tolerar la desecación. En Este Contexto, la Presencia de Pyropia columbina en la zona alta del intermareal sí Explica Por Su excepcional tolerancia fisiológica a la desecación. Este Estudio explora las Vías Metabólicas involucradas en la tolerancia a la desecación en P. columbina, un Través de la Caracterización de do transcriptoma Bajo Condiciones de hidratación contrastantes. Se obtuvó 1410 TER provenientes de dos Librerías de substracción de ADNc de frondas Naturalmente hidratadas y desecadas. Los transcriptomas de emba Librerías contienen transcritos de Diversas Rutas Metabólicas Relacionadas a la tolerancia. Entre el los transcritos expresados ​​15% estan involucrados en la Síntesis de Proteínas, do Procesamiento y degradacion, 14,4% Asociados un Fotosíntesis y cloroplasto, el 13,1% una mitocondrial Respiración and function, 10,6% al metabolism de la Pared Celular y 7,5% a la Actividad ANTIOXIDANTE, Proteínas chaperonas y factors de Defensa (catalasa, tiorredoxina, Proteínas de choque térmico, P450 citocromo). In Ambás Librerías sí DESTACA La Presencia De genes / Proteínas no descritos en algas. Proporciona Información This El Primer Trabajo molecular Que Estudia la tolerancia a desecación en P. columbina y Sus Resultados Ayudan a explicar los patrones clásicos de Distribución descritos párr algas en la zona intermareal. Palabras clave: Pyropia, desecación porción Estrés, EST, macroalgas, transcriptómica, Proteínas.ABSTRACT. In rocky shores, desiccation is triggered by daily tide changes, and experimental evidence suggests that local distribution of algal species across the intertidal rocky zone is related to their capacity to tolerate desiccation. In this context, the permanence of Pyropia columbina in the high intertidal rocky zone is explained by its exceptional physiological tolerance to desiccation. This study explored the metabolic pathways involved in tolerance to desiccation in the Chilean P. columbina, by characterizing its transcriptome under contrasting conditions of hydration. We obtained 1,410 ESTs from two subtracted cDNA libraries in naturally hydrated and desiccated fronds. Results indicate that transcriptome from both libraries contain transcripts from diverse metabolic pathways related to tolerance. Among the transcripts differentially expressed, 15% appears involved in protein synthesis, processing and degradation, 14.4% are related to photosynthesis and chloroplast, 13.1% to respiration and mitochondrial function (NADH dehydrogenase and cytochrome c oxidase proteins), 10.6% to cell wall metabolism, and 7.5% are involved in antioxidant activity, chaperone and defense factors (catalase, thioredoxin, heat shock proteins, cytochrome P450). Both libraries highlight the presence of genes/proteins never described before in algae. This information provides the first molecular work regarding desiccation tolerance in P. columbina, and helps, to some extent, explaining the classical patterns of ecological distribution described for algae across the intertidal zone.http://ref.scielo.org/jm5rc

Desarrollo y caracterización de seis marcadores microsatélites para el alga roja chilena pyropia orbicularis

Indexación: Scopus.Mariculture of edible Porphyra/Pyropia species, which are cosmopolitan red foliose algae, represent an important source of income for the pharmaceutical and food industries. In Chile, the most common alga of this complex is Pyropia orbicularis (Bangiales, Rhodophyta). Here we report 6 microsatellite markers obtained from P. orbicularis through a genomic library from 10 individuals of the gametophytic phase by next generation (Illumina) sequencing. Polymorphism analyses were done from 10 individuals of the conchocelis phase, revealing an allelic diversity ranging from three to six alleles per locus, and observed heterozygosity (HO) and expected heterozygosity (HE) ranging from 0.200 to 0.995, and 0.250 to 0.610, respectively. A large proportion of genetic variance (61%) in P. orbicularis was among individuals within population, and 39% genetic variance was among populations. Nonetheless, these results should be interpreted with caution; further research using larger sample sizes is required. These polymorphic markers could be useful in future studies on population genetic structure, for conservation and applied purposes.https://revistas.uv.cl/index.php/rbmo/article/view/235

Indoor culture scaling of Gracilaria chilensis (Florideophyceae, Rhodophyta): The effects of nutrients by means of different culture media: Escalada de cultivo en interiores de Gracilaria chilensis (Florideophyceae, Rhodophyta): Efectos de los nutrientes por diferentes medios de cultivo

Gracilaria chilensis is distributed in New Zealand (including Chatham Island) and South America. This species has a three-stage sexual life cycle, as well as asexual and vegetative reproduction, and is commercially important as it is a valuable source for producing agar. However, basing the crops exclusively on clonal reproduction and vegetative propagation has led to a reduction in their genotypic diversity, an increase in their susceptibility to infection by epiphytes, and a decrease in their quality. Thus, it is important to establish indoor cultures of G. chilensis from thalli with a mixed reproductive regime (sexual and asexual) that maintains the genetic variability of the cultivars. In this study, the biomass, growth rate, and productivity of indoor cultures of G. chilensis were evaluated (as a first approach) using various culture media (i.e., von Stosch medium (VS), Basfoliar® Aktiv (BF), and mixtures of VS and BF, namely, VS/BF-A and VS/BF-B). The VS/BF-A medium showed the best results in terms of biomass (51.8 ± 3.7 g m–2), growth rate (4.55 ± 0.43 %d–1), and productivity (14 g m–2 d–1), including the occurrence of thalli with cystocarps. The positive results using the VS/BF-A medium could be attributed to the fact that BF provides different elements (K, Cu, Mo, and Zn) that are crucial, since they are involved in numerous physiological functions in the algae, and also to the N:P ratio utilized (1:1), which positively affects growth and productivity. This information provides pivotal updated knowledge regarding cultures of G. chilensis under controlled conditions, promoting its successful cultivation for productive purposes