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Current applications and future perspectives of nanotechnology for the preservation and enhancement of grain and seed traits
(2023-07-22) Vega Fernández, Laura; Quesada Grosso, Ricardo; Viñas Meneses, María; Irías Mata, Andrea Paola; Montes de Oca Vásquez, María Gabriela; Vega Baudrit, José Roberto; Jiménez, Víctor M.
Achieving food security worldwide is a major challenge because nearly 700 million people face hunger and more than 2 billion are affected by mineral and vitamin deficiencies (the so-called “hidden hunger”). Food insecurity can be addressed by implementing sustainable food systems to improve postharvest management of seeds (the propagation structures for the next crop generation) and grains (consumed as food or feed), to which nano-enabled technologies can greatly contribute. This chapter provides an updated description of the use of nanotechnology to improve seed and grain traits. First, the use of nano-priming and nano-coating techniques with different nanomaterials, the mechanisms involved, and their effects on seed germination and seedling growth are described. Further-more, how to prevent and reduce mycotoxin contamination in grains, where some examples of nanoformulations are addressed (nanoparticles, nanocarriers, nanoli-posomes, nanocapsules, nanoemulsions or nanoformulations, and nanoadsorbents) is also described. Under this scope, the challenges and future perspectives of this technology are also described, emphasizing the relevance of involving stakeholders (including consumer perception) and considering human health and environmental impacts.
A chemosynthetic ecotone—“chemotone”—in the sediments surrounding deep-sea methane seeps
(2021-03-29) Ashford, Oliver Simon; Guan, Shuzhe; Capone, Dante; Rigney, Katherine; Rowley, Katelynn; Orphan, Victoria; Mullin, Sean W.; Dawson, Kat S.; Cortés Núñez, Jorge; Rouse, Greg W.; Mendoza, Guillermo F.; Lee, Raymond W.; Cordes, Erick E.; Levin, Lisa Ann
Ecotones have been described as “biodiversity hotspots” from myriad environments, yet have not been studied extensively in the deep ocean. While physiologically challenging, deep-water methane seeps host highly productive communities fueled predominantly by chemosynthetic pathways. We hypothesized that the biologi cal and geochemical influence of methane seeps extends into background habitats, resulting in the formation of a “chemotone” where chemosynthesis-based and photosynthesis-based communities overlap. To investigate this, we analyzed the macrofaunal assemblages and geochemical properties of sediments collected from “active,” “transition” (potential chemotone), and “background” habitats surrounding five Costa Rican methane seeps (depth range 377–1908 m). Sediment geochemistry demonstrated a clear distinction between active and transi tion habitats, but not between transition and background habitats. In contrast, biological variables confirmed the presence of a chemotone, characterized by intermediate biomass, a distinct species composition (including habitat endemics and species from both active and background habitats), and enhanced variability in species composition among samples. However, chemotone assemblages were not distinct from active and/or back ground assemblages in terms of faunal density, biological trait composition, or diversity. Biomass and faunal sta ble isotope data suggest that chemotones are driven by a gradient in food delivery, receiving supplements from chemosynthetic production in addition to available photosynthetic-based resources. Sediment geochemistry suggests that chemosynthetic food supplements are delivered across the chemotone at least in part through the water column, as opposed to reflecting exclusively in situ chemosynthetic production in sediments. Manage ment efforts should be cognisant of the ecological attributes and spatial extent of the chemotone that surrounds deep-sea chemosynthetic environments.
Sexual dimorphism in the methane seep-dwelling Costa Rican yeti crab Kiwa puravida (Decapoda: Anomura: Kiwaidae)
(2022-11-08) Azofeifa Solano, Juan Carlos; Pereira, Olívia S.; Jayne Cowell, Emily; Cordes, Erik E.; Levin, Lisa Ann; Goffredi, Shana K.; Cortés Núñez, Jorge
Deep-sea chemosynthesis-based ecosystems support unique biological communities, but human impacts are an increasing threat. Understanding the life-history traits of species from deep-sea chemosynthesis-based ecosystems can help to develop adequate management strategies, as these can have impacts on ecological responses to changes in the environment. Here we examined the occurrence of sexual dimorphism in the yeti crab Kiwa puravida, an endemic species from the Costa Rican Pacific margin that aggregates at active methane seeps and depends on chemosynthetic bacteria for nutrition. The two morphological features examined included the claws, suspected to be under sexual selection and used for defense, and the carpus of the second pereopod not suspected to be under sexual selection. A total of 258 specimens, 161 males, 81 females, 16 juveniles, were collected from Mound 12 at 1,000-1,040 m depth in 2017 and 2018 and analyzed. We found that males have larger and wider claws than females, while there were no differences in carpus length. These results suggest that claw weaponry is under sexual selection in K. puravida, which is probably related to the mating system of this deep-sea species. This is the first attempt to study the reproductive biology of K. puravida, and additional observations will be necessary to shed more light on this matter.
The lancelet asymmetron lucayanum complex in Cocos Island National Park, Pacific Costa Rica
(2012-10-01) Sibaja Cordero, Jeffrey Alejandro; Troncoso, Jesús S.; Cortés Núñez, Jorge
The lancelet Asymmetron lucayanum complex was collected from subtidal (5–42 m) sandy bottom during a benthic survey designed to describe the biota of Cocos Island National Park (Parque Nacional Isla del Coco), Costa Rica, a World Heritage Site. Taxonomically significant characters of A. lucayanum (number of myotomes, gonads only on the right side of the body, shape of metapleural folds) are discussed. These lancelets were living in poorly sorted and slightly gravelly sand. Although this taxon has a circumtropical distribution, this is the first time it has been collected anywhere in the eastern Pacific.
Manual de laboratorio: técnicas instrumentales de análisis
(2018) Pérez López, Esteban; Mora Quesada, Wilber; González Araya, María Nidia