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The coastline is a heterogeneous and highly dynamic environment influenced by abiotic and biotic variables affecting the temporal stability of genetic diversity and structure of marine organisms. The aim of this study was to determine how much the genetic structure of four species of marine Bangiales vary in time and space. Partial sequences of the cytochrome oxidase I (COI) gene obtained from two Pyropia (Py. sp. CHJ and Py. orbicularis) and two Porphyra (P. mumfordii and P. sp. FIH) species were used to compare the effect of the 40° S/41° S biogeographic break (spatial-regional scale) and the one of the Valdivia River discharges (spatial-local scale) and determine their temporal stability. Four seasonal samplings were taken during 1 year at five sites, one site located in Melinka (Magallanes province) and four sites along the coast of Valdivia (Intermediate area), on both sides of the river mouth. Results showed a strong genetic spatial structure at regional scale (ΦST > 0.4) in Py. sp. CHJ, Py. orbicularis, and P. mumfordii, congruent with the 41° S/42° S biogeographic break. A potential barrier to gene flow, related to the Valdivia River discharge, was detected only in P. mumfordii. In P. sp. FIH, spatial genetic structure was not detected at any scale. The genetic structure of all four species is stable throughout the year. The potential effect of main currents and river discharge in limiting the transport of Bangiales spores are discussed. We propose that both a restricted propagule dispersal and the formation potential for persistent banks of microscopic stages could lead to a temporally stable spatial partitioning of genetic variation in bladed Bangiales.

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Morphologically similar but genetically distinct species have been termed cryptic and most have been assumed to be ecologically similar. However, if these species co-occur at a certain spatial scale, some niche differences at finer scales should be expected to allow for coexistence. Here, we demonstrate the existence of a disjointed distribution of cryptic bladed Bangiales along spatial (intertidal elevations) and temporal (seasons) environmental gradients. Bladed Bangiales were identified and quantified across four intertidal elevations and four seasons for one year, at five rocky intertidal sites (between 39° S and 43° S) in southern Chile. Species determination was based on partial sequences of the mitochondrial cytochrome c oxidase 1 (COI) gene amplification. To assess species gross morphology, thallus shape, color, and maximum length and width were recorded. Hundreds of organisms were classified into nine Bangiales species belonging to three genera (i.e., Fuscifolium, Porphyra, and Pyropia), including five frequent (>97% of specimens) and four infrequent species. All species, except for Pyropia saldanhae, had been previously reported along the coasts of Chile. The thallus shape and color were very variable, and a large overlap of the maximum width and length supported the cryptic status of these species. Multivariate analyses showed that the main variable affecting species composition was intertidal elevation. Species such as Py. orbicularis were more abundant in low and mid intertidal zones, while others, such as Po. mumfordii and Po. sp. FIH, were principally observed in high and spray elevations. Despite all numerically dominant species being present all year long, a slight effect of seasonal variation on species composition was also detected. These results strongly support the existence of spatial niche partitioning in cryptic Bangiales along the Chilean rocky intertidal zone.

RESUMO

BACKGROUND: Sunscald is a physiological disorder that occurs in many horticultural products when exposed to excessive solar radiation and high temperatures. Traditionally, sunscald is controlled using physical barriers that reflect radiation, however this practice is not always efficient. A possible alternative would be the use of chemical barriers, such as mycosporine-like amino acids (MAAs), which protect aquatic organisms against ultraviolet (UV) radiation. Thus, this study aimed to develop a lipid-based emulsion containing MAAs for using in the preharvest of horticultural products. RESULTS: Emulsions were developed using 10% (w/v) of corn oil (CO) and soybean oil (SO), carnauba wax (CW), and beeswax (BW) as lipid bases (LBs). The emulsion containing CW and ammonium hydroxide was the most stable, resembling commercial wax. Therefore, this formulation was used as the basis for the incorporation of the commercial product Helioguard™ 365, a source of MAA, in concentrations of 0%, 1%, 2%, and 4% (v/v). The MAA incorporation resulted in little modifications in the stability of the emulsion, providing an increase in the absorbance with peaks in the UV-B ranging from 280 to 300 nm. CONCLUSION: The lipid-base emulsion containing MAAs could be used as a chemical barrier to control sunscald in horticultural products. © 2021 Society of Chemical Industry.

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Red 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.

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Os alimentos funcionais são hoje prioridade de pesquisa nas áreas de nutrição e tecnologia de alimentos, levando-se em conta o interesse do consumidor em alimentos mais saudáveis. Este projeto teve como objetivo elaborar uma barra de cereal com adição da alga Porphyra tenera, morango, chocolate ao leite e meio amargo. Após a elaboração da barra, foram realizadas análises bromatológicas, sensoriais e a rotulagem nutricional. O trabalho foi desenvolvido no Laboratório de Bromatologia e Tecnologia de Alimentos do Centro Universitário de Caratinga, Minas Gerais. Foram produzidas duas amostras, sendo uma tradicional e a outra com adição de algas. A aceitabilidade da barra de cereal com adição de algas foi satisfatória (69% dos provadores), considerando que alimentos à base de algas não fazem parte da cultura brasileira, mas, em razão de suas propriedades nutricionais e funcionais, devem ser inseridos novos produtos explorando seus benefícios. Por meio das análises físico-químicas, a porcentagem de carboidratos foi de 53,27%; lipídeos, de 12,19%; e proteínas, de 5,64%. Observou-se que o produto é rico em fósforo, mineral essencial para o melhor funcionamento do organismo. A alga Porphyra tenera é rica em vários outros nutrientes, não analisados neste estudo, por causa das limitações dos equipamentos necessários do Laboratório de Bromatologia da instituição.

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Previous study has shown that Porphyra conchocelis is sensitive to high levels of PAR (400-700 nm) as well as ultraviolet radiation (UVR: 280-400 nm), resulting in high inhibition of photosynthesis. However, little is known about whether the inner covering layer of the shell, in which the conchocelis lives, may provide protection against solar UVR. Our study indicates that the covering calcareous matrix is about 0.06 mm thick, transmitting 63, 47, and 28% of PAR, ultraviolet radiation A (UVA: 315-400 nm), and ultraviolet radiation B (UVB: 280-315 nm), respectively. We used a shading layer that simulated the above transmissions, and the effective quantum yield of PSII and photosynthetic carbon fixation in the conchocelis increased to greater extents in the presence of UVA or UVB. Attenuation of UVA by 19% and UVB by 37% due to the shading layer increased the PSII yield by 44%-77% and photosynthetic carbon fixation by about 60%. Our study clearly shows that the photosynthetic machinery of Porphyra haitanensis T. J. Chang et B. F. Zheng conchocelis was efficiently protected from harmful UVR by the covering calcareous matrix.