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Modeling the growth, yield and N dynamics of wheat for decoding the tillage and nitrogen nexus in 8-years long-term conservation agriculture based maize-wheat system

C.M. Parihar Dipaka Ranjan Sena Prakash Chand Ghasal Shankar Lal Jat Yashpal Singh Saharawat Mahesh Gathala Upendra Singh Hari Sankar Nayak (2024, [Artículo])

Context: Agricultural field experiments are costly and time-consuming, and their site-specific nature limits their ability to capture spatial and temporal variability. This hinders the transfer of crop management information across different locations, impeding effective agricultural decision-making. Further, accurate estimates of the benefits and risks of alternative crop and nutrient management options are crucial for effective decision-making in agriculture. Objective: The objective of this study was to utilize the Crop Environment Resource Synthesis CERES-Wheat model to simulate crop growth, yield, and nitrogen dynamics in a long-term conservation agriculture (CA) based wheat system. The study aimed to calibrate the model using data from a field experiment conducted during the 2019-20-2020-21 growing seasons and evaluation it with independent data from the year 2021–22. Method: Crop simulation models, such as the Crop Environment Resource Synthesis CERES-Wheat (DSSAT v 4.8), may provide valuable insights into crop growth and nitrogen dynamics, enabling decision makers to understand and manage production risk more effectively. Therefore, the present study employed the CERES-Wheat (DSSAT v 4.8) model and calibrated it using field data, including plant phenological phases, leaf area index, aboveground biomass, and grain yield from the 2019-20-2020-21 growing seasons. An independent dataset from the year 2021–22 was used for model evaluation. The model was used to investigate the relationship between growing degree days (GDD), temperature, nitrate and ammonical concentration in soil, and nitrogen uptake by the crop. Additionally, the study explored the impact of contrasting tillage practices and fertilizer nitrogen management options on wheat yields. The experimental site is situated at ICAR-Indian Agricultural Research Institute (IARI), New Delhi, representing Indian Trans-Gangetic Plains Zone (28o 40’N latitude, 77o 11’E longitude and an altitude of 228 m above sea level). The treatments consist of four nitrogen management options, viz., N0 (zero nitrogen), N150 (150 kg N ha−1 through urea), GS (Green seeker based urea application) and USG (urea super granules @150 kg N ha−1) in two contrasting tillage systems, i.e., CA-based zero tillage (ZT) and conventional tillage (CT). Result: The outcomes exhibited favorable agreement between the model’s simulations and the observed data for crop phenology (With less than 2 days variation in 50% onset of flowering), grain and biomass yield (Root mean square error; RMSE 336 kg ha−1 and 649 kg ha−1, respectively), and leaf area index (LAI) (RMSE 0.28 & normalized RMSE; nRMSE 6.69%). The model effectively captured the nitrate-N (NO3−-N) dynamics in the soil profile, exhibiting a remarkable concordance with observed data, as evident from its low RMSE = 12.39 kg ha−1 and nRMSE = 13.69%. Moreover, as it successfully simulated the N balance in the production system, the nitrate leaching and ammonia volatilization pattern as described by the model are highly useful to understand these critical phenomena under both conventional tillage (CT) and CA-based Zero Tillage (ZT) treatments. Conclusion: The study concludes that the DSSAT-CERES-Wheat model has significant potential to assess the impacts of tillage and nitrogen management practices on crop growth, yield, and soil nitrogen dynamics in the western Indo-Gangetic Plains (IGP) region. By providing reliable forecasts within the growing season, this modeling approach can facilitate better planning and more efficient resource management. Future implications: The successful implementation of the DSSAT-CERES-Wheat model in this study highlights its applicability in assessing crop performance and soil dynamics. Future research should focus on expanding the model’s capabilities by reducing its sensitivity to initial soil nitrogen levels to refine its predictions further. Moreover, the model’s integration with decision support systems and real-time data can enhance its usefulness in aiding agricultural decision-making and supporting sustainable crop management practices.

Nitrogen Dynamics Mechanistic Crop Growth Models Crop Simulation CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA NITROGEN CONSERVATION AGRICULTURE WHEAT MAIZE CROP GROWTH RATE SIMULATION MODELS

INFLUENCIA DE CONDICIONES AMBIENTALES SOBRE LA DISTRIBUCIÓN, ABUNDANCIA Y DESARROLLO DE LARVAS DE Totoaba macdonaldi (Gilbert, 1890), EN EL ALTO GOLFO DE CALIFORNIA

Marcelo Vidal Curiel Bernal (2023, [Tesis de doctorado])

"La presente tesis aborda una investigación sobre la biología, ecología y crecimiento de la Totoaba macdonaldi en el alto golfo de California. La totoaba, una especie endémica a esta región se encuentra actualmente en peligro de extinción debido a una serie de amenazas como: cambios en su ecosistema reproductivo y de crianza, pesca, incidental de juveniles e ilegal de adultos. Aunque en los últimos 30 años la población dio signos de recuperación, existen indicios de que tanto la población adulta como las abundancias de larvas presentan una tendencia decreciente. Lo que resalta la importancia de estudiar cómo la variabilidad ambiental incide en la distribución y abundancia de larvas de totoaba y subsecuentemente en el stock recluta de la especie. El estudio comienza con un análisis de la variabilidad del crecimiento individual en etapas juveniles y adultas de la totoaba. Para este propósito, se utiliza la varianza observada como elemento clave para parametrizar modelos de crecimiento individual. Los resultados indican que este enfoque proporciona estimaciones sólidas de los parámetros de crecimiento. A continuación, se investiga el crecimiento de las larvas de totoaba en condiciones de cultivo. Los datos revelan que un modelo sigmoideo describe mejor el crecimiento y se identifican dos puntos de inflexión en el crecimiento de las larvas. Estos hallazgos tienen importantes implicaciones para la cría y el cultivo de la totoaba para efectos de repoblación. Por último, se analiza la ecología y el transporte de las larvas de totoaba en el alto golfo de California. Se identifica una ventana óptima para el desove de la totoaba en términos de temperatura y concentración de clorofila, y se sugiere que las condiciones ambientales y la distribución de los adultos pueden influir en las abundancias de larvas en diferentes años. Además, se destaca la importancia del frente permanente al sur del alto golfo de California como una posible zona de acumulación de larvas como factor que contribuye al endemismo en la región. En conjunto, esta tesis representa un enfoque multidisciplinario para comprender los aspectos clave de la biología, ecología y crecimiento de la totoaba en el alto golfo de California. Los resultados proporcionan información valiosa para la conservación de esta especie amenazada y destacan la importancia de un enfoque integral en la gestión de los recursos marinos en esta región única."

"The following thesis addresses a research on the biology, ecology, and growth of Totoaba macdonaldi in the upper gulf of California. The totoaba, a fish species endemic to this region, is currently endangered due to a series of threats such as: changes in its reproductive and breeding ecosystem, juvenile bycatch, and illegal fishing. Although over the last 30 years, the population has shown signs of recovery, there are indications that both the adult population and larval abundances are on a declining trend. This underscores the importance of studying how environmental variability affects the distribution and abundance of totoaba larvae and subsequently the recruitment stock of the species. The study begins with an analysis of growth in juvenile and adult stages of the totoaba. For this purpose, observed variance is used to parameterize individual growth models. Results indicate that this approach provides robust estimates of growth parameters. Next, the growth of cultivated totoaba larvae is investigated. The data reveal that a sigmoid model better describes the growth in the early life stages of the totoaba, and two inflection points in larval growth are identified. These findings have important implications for the breeding and cultivation of the totoaba for restocking purposes. Finally, the ecology and transport of totoaba larvae in the upper gulf of California are analyzed. An optimal window for totoaba spawning in terms of temperature and chlorophyll concentration is identified, and it is suggested that environmental conditions and the distribution of adults may influence larval abundances in different years. Additionally, the importance of the permanent front to the south of the upper gulf of California is highlighted as a possible larval accumulation zone and a contributing factor to endemism in the region. Overall, this thesis represents a multidisciplinary approach to understanding key aspects of the biology, ecology, and growth of the totoaba in the upper gulf of California. The results provide valuable information for the conservation of this threatened species and underscore the importance of a comprehensive approach in the management of marine resources in this unique region."

Variabilidad ambiental, crecimiento, dispersión, rutas larvarias Environmental variability, growth, dispersion, larval routes CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PECES Y FAUNA SILVESTRE PROPAGACIÓN Y ORDENACIÓN PROPAGACIÓN Y ORDENACIÓN

Using Observed Residual Error Structure Yields the Best Estimates of Individual Growth Parameters

Marcelo Vidal Curiel Bernal EUGENIO ALBERTO ARAGON NORIEGA MIGUEL ANGEL CISNEROS MATA LAURA SANCHEZ VELASCO SYLVIA PATRICIA ADELHEID JIMENEZ ROSENBERG ALEJANDRO FRANCISCO PARES SIERRA (2021, [Artículo])

"Obtaining the best possible estimates of individual growth parameters is essential in studies of physiology, fisheries management, and conservation of natural resources since growth is a key component of population dynamics. In the present work, we use data of an endangered fish species to demonstrate the importance of selecting the right data error structure when fitting growth models in multimodel inference. The totoaba (Totoaba macdonaldi) is a fish species endemic to the Gulf of California increasingly studied in recent times due to a perceived threat of extinction. Previous works estimated individual growth using the von Bertalanffy model assuming a constant variance of length-at-age. Here, we reanalyze the same data under five different variance assumptions to fit the von Bertalanffy and Gompertz models. We found consistent significant differences between the constant and nonconstant error structure scenarios and provide an example of the consequences using the growth performance index _0 to show how using the wrong error structure can produce growth parameter values that can lead to biased conclusions. Based on these results, for totoaba and other related species, we recommend using the observed error structure to obtain the individual growth parameters."

multimodel inference, error structure, totoaba, growth performance BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) FISIOLOGÍA ANIMAL FISIOLOGÍA ANIMAL

EVALUACIÓN DE LA ACTIVIDAD Y EXPRESIÓN GÉNICA DE ENZIMAS ANTIOXIDANTES (SOD, GPX, GST, GR y CAT) COMO BIOMARCADORES DE EXPOSICIÓN A FTALATOS EN CULTIVO CELULAR

Elizabeth Brassea Pérez (2023, [Tesis de doctorado])

"El plastificante bis(2-etilhexilo) ftalato (DEHP) altera el equilibrio entre la producción de especies reactivas de oxígeno y las defensas antioxidantes. A pesar de la información disponible sobre los efectos tóxicos del DEHP en organismos modelo, la respuesta celular al DEHP en especies naturalmente adaptadas para tolerar el estrés oxidativo aún no se ha explorado. Los mamíferos marinos están naturalmente adaptados para hacer frente al estrés oxidativo derivado de la isquemia/reperfusión inducida por el buceo. El objetivo de este estudio fue comparar los cambios en los indicadores de estrés oxidativo asociados al DEHP en células de músculo esquelético de humanos (Homo sapiens sapiens) y lobos marinos de California (Zalophus californianus). Se recolectaron muestras de músculo abdominal de mujeres sanas sometidas a cesárea programada, tras obtener su consentimiento informado. Las muestras de músculo de lobo marino se obtuvieron de crías encontradas recientemente muertas en la colonia de Los Islotes, Golfo de California. Las células de músculo esquelético se aislaron y cultivaron en condiciones estándar. Las células se dividieron en dos grupos. Un grupo fue expuesto a DEHP (1 mM) durante 13 días (n=25; exposición), el otro grupo se mantuvo bajo condiciones control, es decir sin DEHP añadido (n=25; control). Se midió la producción de radical superóxido (O2•-), el daño oxidativo, la actividad de enzimas antioxidantes y la expresión génica mediante métodos espectrofotométricos y RT-qPCR. En células expuestas al DEHP la producción de O2•- y la actividad de superóxido dismutasa (SOD) fueron mayores que en las células bajo condiciones control para ambas especies. La actividad de glutatión S-transferasa (GST) y los niveles de carbonilos proteicos (PC) aumentaron significativamente en las células humanas expuestas a DEHP, y no significativamente en las células de lobo marino. Por el contrario, las actividades de glutatión peroxidasa (GPx) y catalasa (CAT) aumentaron significativamente en las células de lobo marino, pero no en las de humano expuestas a DEHP. Se observó una expresión diferencial de los genes implicados en el metabolismo redox entre las células control y expuestas a DEHP y entre especies. Los patrones de expresión de 26 y 19 genes fueron significativamente diferentes en las células humanas y de lobo marino, respectivamente, después de la exposición a DEHP. En las células humanas, la expresión de la GST1 microsomal y la GST (κ, μ, θ, ω y ᴢ) fue mayor,

"The plasticizer bis (2-ethylhexyl) phthalate (DEHP) dysregulates the balance between reactive oxygen species production and antioxidant defenses. Despite the information available on DEHP’s hazardous effects in model species, the cellular response to DEHP in organisms naturally adapted to tolerate oxidative stress remains unexplored. Marine mammals are naturally adapted to cope with oxidative stress derived from diving-induced ischemia/reperfusion. The objective of this study was to compare changes in oxidative stress indicators induced by DEHP in human (Homo sapiens sapiens) and California sea lion (Zalophus californianus) skeletal muscle cells. Abdominal muscle samples were collected from healthy women undergoing planned cesarean surgery at full term after obtaining informed consent. Sea lion muscle samples were obtained from recently deceased pups at Los Islotes rookery, Gulf of California. Skeletal muscle cells were isolated and cultured under standard conditions. Cells were divided into two groups. One group was exposed to 1 mM DEHP for 13 days (n=25; treatment), and the other served as a control (n=25; no DEHP). Superoxide radical (O2•-) production, oxidative damage, antioxidant enzyme activities and gene expression were measured using spectrophotometric methods and RT-qPCR. DEHP exposure increased O2•- production and superoxide dismutase (SOD) activity in both species. While the activity of glutathione S-transferase (GST) and protein carbonyls (PC) levels significantly increased in human cells, these indicators showed a non-significant elevation in sea lion cells. In contrast, glutathione peroxidase (GPx) and catalase (CAT) activities increased significantly in sea lion but not in human cultures exposed to DEHP. Genes involved in redox metabolism showed differential expression between treatments and species. DEHP exposure led to widespread modifications in gene expression patterns, with 26 and 19 differentially expressed genes in human and sea lion cells, respectively. In human cells, DEHP increased GST1 and GST (κ, μ, θ, ω, and ᴢ), while suppressing 8-oxoguanine DNA glycosylase (OGG1), CAT, GR, and nuclear factor erythroid 2-related factor 2 (NRF2) expression, suggesting increased oxidative stress and phase two detoxification processes. In contrast, DEHP increased OGG1, NRF2, GPx2 and SOD3 expression, suggesting that DEHP activates antioxidant defenses in sea lion cells, potentially contributing to maintain redox homeostasis and avoid oxidative...

Contaminantes emergentes, enzimas antioxidantes, estrés oxidativo, mamíferos, Una Salud Antioxidant enzymes, emerging pollutants, mammals, One Health, oxidative stress BIOLOGÍA Y QUÍMICA QUÍMICA BIOQUÍMICA ENZIMOLOGIA ENZIMOLOGIA

Recent advances on research of native prawn Macrobrachium americanum (Decapoda: Palaemonidae) with aquaculture and conservation purposes

Yuneisy Milagro Agüero Fernández MIRIAM VICTORIA MARTIN MANZO MARITZA LOURDES SOBERANES YEPIZ Marcelo Ulises García Guerrero Yuniel Méndez Martínez Luis Hector Hernandez Hernandez Laura S López Greco Edilmar Cortés Jacinto (2022, [Artículo])

"Where good management practices on aquaculture are mandatory. The economic and ecological importance of prawns of the Genus Macrobrachium cause an impact at a global level involving economic, academic and social aspects. Macrobrachium americanum appears as one of the genus species with high nutritional value and an economic demand in the national and international markets, as well as a vital income for fisherman and producers of this species. For researchers, it is a challenge to find solutions to culture and propose conservation measures for M. americanum with emphasis on development, nutrition and reproduction. Although there are scientific studies supporting the economic importance of this species, our knowledge about its cultivation, reproduction and conservation is limited. This paper summarizes the latest studies made in cooperation with M. americanum in research lead by the Centro de Investigaciones Biológicas del Noroeste, Mexico. After several years of continuous research, it is considered that those efforts have produced useful information for the sustainable exploitation, conservation and basic management practices of this species."

Freshwater ecosystem, growth rate, native prawn species, conservation, sustainable fishing BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) ECOLOGÍA ANIMAL ECOLOGÍA ANIMAL

PROPUESTA DE MANEJO DE LA PESQUERÍA EMERGENTE DE MERLUZA DEL PACÍFICO NORTE Merluccius productus EN EL GOLFO DE ULLOA, BAJA CALIFORNIA SUR

PABLO MORA ZAMACONA (2023, [Tesis de doctorado])

"La merluza del Pacífico Merluccius productus se distribuye desde Alaska hasta el sur de México, con una población particular descrita al sur de la península de Baja California conocida como merluza enana, de la que poco se sabe. Dicha población actualmente no es pescada comercialmente, por lo que representa un recurso con potencial de explotación. Las pesquerías potenciales y emergentes crean desafíos y oportunidades para los administradores pesqueros que necesitan tomar decisiones sobre cómo gestionar de forma sostenible una pesquería previa a su inicio. Este trabajo propone y analiza posibles medidas alternativas de gestión pesquera para esta potencial pesquería, bajo incertidumbre biológica y de mercado. Debido al desconocimiento de diversos aspectos de la biología del recurso primeramente se analizó el crecimiento individual del stock y posteriormente se realizó un análisis bioeconómico de la potencial pesquería.

Para el análisis del crecimiento individual se utilizó un total de 240 otolitos y datos de longitud patrón de 932 especímenes muestreados de mayo a diciembre de 2015. La formación anual de incrementos en los otolitos se verificó mediante la relación de incremento marginal y el análisis de borde. La edad se estimó a partir de recuentos de anillos en secciones sagitales de otolitos y el crecimiento se analizó mediante un enfoque de inferencia multimodelo. Se consideraron los modelos de crecimiento de von Bertalanffy (VBGM), VBGM generalizado, Gompertz, Logístico y Johnson, los cuales se ajustaron a conjuntos de datos de talla a la edad observados y retrocalculados agrupados por sexo. Según el criterio de información de Akaike, el VBGM generalizado fue el más apropiado para las hembras (L∞= 31.36 cm, k= 0.15 cm año-1), mientras que el VBGM proporcionó el mejor ajuste para los machos (L∞= 25.35 cm, k= 0.28 cm año-1).

El análisis bioeconómico de alternativas de manejo para una potencial pesquería de merluza enana indicó que una nueva pesquería de dicho stock podría ser biológicamente sostenible y económicamente rentable, bajo un conjunto de estrategias de gestión y reglas de control. Se recomienda un acceso limitado con bajo esfuerzo pesquero ya que resulta más redituable por barco y biológicamente precautorio, considerando la alta incertidumbre asociada con la explotación de una población virgen..."

"The Pacific hake Merluccius productus is distributed from Alaska to southern Mexico, with a particular population described south of the Baja California peninsula known as dwarf hake, about which little is known. This population is not currently commercially fished; hence it represents a resource with potential for exploitation. Potential and emerging fisheries create challenges and opportunities for fishery managers who need to make decisions about how to sustainably manage a fishery prior to its initiation. This work proposes and analyzes possible alternative fishery management measures for this potential fishery, under biological and market uncertainty. Due to the lack of knowledge of various aspects of the biology of the resource, the individual growth of the stock was first analyzed and subsequently a bioeconomic analysis of the potential fishery was carried out.

A total of 240 otoliths and standard-length data from 932 specimens sampled from May to December 2015 were used for the analysis of individual growth. The annual formation of otolith increments was verified using the marginal increment analysis and the edge analysis. Age was estimated from annuli counts in sagittal sections of otoliths and growth was analyzed using a multi-model inference approach. The von Bertalanffy growth models (VBGM), generalized VBGM, Gompertz, Logistic and Johnson growth models were considered, which were fitted to observed and back calculated length-at-age data sets grouped by sex. According to Akaike's information criterion, the generalized VBGM was the most appropriate for females (L∞= 31.36 cm, k= 0.15 cm year-1), while the VBGM provided the best fit for males (L∞= 25.35 cm, k= 0.28 cm year-1).

The bioeconomic analysis of management alternatives for a potential dwarf hake fishery indicated that a new fishery for said stock could be biologically sustainable and economically profitable, under a set of management strategies and control rules. Limited access with low fishing effort is recommended as it is more profitable by boat and biologically precautionary, considering the high uncertainty associated with the exploitation of an unfished stock. Despite the combination of high fishing costs and low prices, the fishery could still be profitable in the long term, although there is risk of overexploitation if high fishing effort is allowed..."

Merluza enana, stock no explotado, crecimiento individual, análisis bioeconómico, pesquería potencial Dwarf hake, unexploited stock, individual growth, bioeconomic analysis, potential fishery CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PECES Y FAUNA SILVESTRE REGLAMENTACIÓN Y CONTROL REGLAMENTACIÓN Y CONTROL

Growth Promoting Activity of Annona muricata L. Leaf Extracts on Lactobacillus casei

NIMCY NOEMI MEZA GUTIERREZ Paola Magallón Servín ROSENDO BALOIS MORALES IZA FERNANDA PEREZ RAMIREZ GRACIELA GUADALUPE LOPEZ GUZMAN GUILLERMO BERUMEN VARELA Pedro Ulises Bautista Rosales (2022, [Artículo])

"Soursop leaves are a source of phytochemical compounds, such as phenolic acids, flavonoids, hydrolyzable tannins, and acetogenins. These compounds can have several types of biological activities. Lactic acid bacteria can uptake phenolic compounds present in plants or fruits. The aim of the present work was to investigate the in vitro effect of hexane, acetone, methanolic, and aqueous extracts of soursop leaves (Annona muricata L.) on the growth, motility, and biofilm formation of Lactobacillus casei, and to determine compounds related to growth. The minimum concentration promoting growth, motility (swimming, swarming, and twitching), and biofilm-forming capacity (crystal violet) were evaluated. The results showed the growth-promoting capacity of acetone and aqueous extracts at low doses 25–50 mg/L, and an inhibition in the four extracts at higher doses of 100 mg/L. The L. casei growth is related to ellagic acid, quercetin rhamnoside, kaempferol dihexoside, quercetin hexoside, secoisolariciresinol, and kaempferol hexoside-rhamnoside. Hexane extract increased the three types of motility, while aqueous maintained swimming and twitching motility similar to control. The four extracts inhibited the biofilm formation capacity."

prebiotic, Lactobacillus, polyphenol, probiotic, growth promoters, soursop leaves CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS AGROQUÍMICA REGULADORES DEL CRECIMIENTO DE LAS PLANTAS REGULADORES DEL CRECIMIENTO DE LAS PLANTAS

Isolation and characterization of endophytic bacteria associated with roots of jojoba (Simmondsia chinensis (Link) Schneid)

RICARDO VAZQUEZ JUAREZ TANIA ZENTENO SAVIN ENRIQUE MORALES BOJORQUEZ Elvia Pérez Rosales Lilia Alcaráz Meléndez María Esther Puente Eduardo Quiroz Guzmán (2017, [Artículo])

"In this communication, the diversity and beneficial characteristics of endophytic bacteria have been studied in Simmondsia chinensis that has industrial importance because of the quality of its seed oil. Endophytes were isolated (N = 101) from roots of the jojoba plants collected, of which eight were identified by partial sequencing of the 16S rDNA gene. The isolated bacteria were Bacillus sp., Methylobacterium aminovorans, Oceanobacillus kimchi, Rhodococcus pyridinivorans and Streptomyces sp. All isolates had at least one positive feature, characterizing them as potential plant growth promoting bacteria. In this study, R. pyridinivorans and O. kimchi are reported as plant growth promoters."

Endophytic bacteria, plant growth promoters, Simmondsia chinensis, seed oil BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA MICROBIOLOGÍA BACTERIOLOGÍA BACTERIOLOGÍA

Phylogenetic relationships of Pseudo-nitzschia subpacifica (Bacillariophyceae) from the Mexican Pacific, and its production of domoic acid in culture

Sonia Quijano (2020, [Artículo])

Pseudo-nitzschia is a cosmopolitan genus, some species of which can produce domoic acid (DA), a neurotoxin responsible for the Amnesic Shellfish Poisoning (ASP). In this study, we identified P. subpacifica for the first time in Todos Santos Bay and Manzanillo Bay, in the Mexican Pacific using SEM and molecular methods. Isolates from Todos Santos Bay were cultivated under conditions of phosphate sufficiency and deficiency at 16°C and 22°C to evaluate the production of DA. This toxin was detected in the particulate (DAp) and dissolved (DAd) fractions of the cultures during the exponential and stationary phases of growth of the cultures. The highest DA concentration was detected during the exponential phase grown in cells maintained in P-deficient medium at 16°C (1.14 ± 0.08 ng mL-1 DAd and 4.71 ± 1.11 × 10−5 ng cell-1 of DAp). In P-sufficient cultures DA was higher in cells maintained at 16°C (0.25 ± 0.05 ng mL-1 DAd and 9.41 ± 1.23 × 10−7 ng cell-1 of DAp) than in cells cultured at 22°C. Therefore, we confirm that P. subpacifica can produce DA, especially under P-limited conditions that could be associated with extraordinary oceanographic events such as the 2013–2016 "Blob" in the northeastern Pacific Ocean. This event altered local oceanographic conditions and possibly generated the presence of potential harmful species in areas with economic importance on the Mexican Pacific coast. © 2020 Quijano-Scheggia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

domoic acid, domoic acid, kainic acid, Article, cell growth, controlled study, diatom, Mexico, morphology, nonhuman, Pacific Ocean, phylogeny, plant cell, plant growth, Pseudo nitzschia, toxin analysis, cell culture technique, classification, diatom, CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA