Comparative study of gonadal development of Ruditapes philippinarum (Adams and Reeve) and Ruditapes decussatus (L.) (Mollusca: Bivalvia): Influence of temperature

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14ºC the reproductive behaviour was similar, both species needing over 2 months to mature. At 18ºC, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias.Se llevaron a cabo experiencias de laboratorio para estudiar la influencia de la temperatura en el comportamiento reproductivo de dos especies de almeja, R. philippinarum y R. decussatus, en su adaptación a las condiciones térmicas en las costas de Galicia. En ambas especies la tasa de desarrollo gonadal está directamente relacionada con el incremento de temperatura. A 14ºC el comportamiento reproductivo es similar y ambas especies necesitan cerca de 2 meses para madurar. A 18ºC, la tasa de desarrollo gonadal de R. philippinarum es mayor que en R. decussatus. No obstante, los resultados de este estudio confirman que ambas especies se han adaptado perfectamente a las condiciones térmicas de las rías de Galicia, si bien, se detectan ciertas diferencias en su comportamiento reproductivo. Así, mientras R. philippinarum acumula ovocitos antes de su emisión parcial o total, en el caso e R. decussatus los gametos se liberan continuamente. En las primeras fases de su desarrollo, el aspecto de la gónada de R. philippinarum es muy heterogéneo, presentándose hasta 3 estados reproductivos simultáneamente, mientras que en R. decussatus el desarrollo gonadal es bastante más uniforme. Otra diferencia concierne al fenómeno de la reabsorción, común en R. philippinarum, pero muy raro en R. decussatus. Estas características pueden sustentar una mayor actividad reproductiva en R. philippinarum comparado con R. decussatus, y un mayor periodo reproductivo en el caso de la primera. Ello puede también representar una cierta ventaje adaptativa, de la especie foráneas (R. philippinarum) frente la especie nativa (R. decussatus), a las condiciones térmicas de las rías de Galicia

Roles of calcium and Mitochondria-Associated Membranes in the development of obesity and diabetes

AbstractObesity has become a public health problem around the world. According to the Organisation for Economic Co-operation and Development (OECD, 2014 report), more than one in three adults in Mexico are obese. It is known that the hypothalamus, a region of the Central Nervous System (CNS), is actively involved in regulating energy homeostasis during obesity. Anatomically, the hypothalamus is composed of several nuclei coordinating body weight and metabolism, including the arcuate nucleus (ARC), which contains neurons co-expressing orexigenic peptides like Agouti-related protein (AgRP), Neuropeptide Y (NPY) and the anorexigenic peptide Pro-opiomelanocortin (POMC). During obesity, the integration and metabolic response in the ARC is disrupted by three molecular mechanisms: (1) activation of endoplasmic reticulum (ER) stress, (2) mitochondrial dysfunction, and (3) increase of ER and mitochondria contacts, known as Mitochondria-Associated Membranes (MAMs). In this context, it is proposed that MAMs formation induces mitochondrial Ca2+ overload and metabolic dysfunction, leading to insulin resistance and diabetes. Recently, MAMs formation has emerged as one of the molecular mechanisms underlying metabolic alterations during obesity. Thus, in this review we will focus on proposing scientific evidence to support the role of the MAMs and their function on calcium regulation during obesity, as an important pathological mechanism in the development of diabetes mellitus type 2

Comparative study of gonadal development of Ruditapes philippinarum (Adams and Revé) and Ruditapes decussatus (L.) (Mollusca, Bivalvia): Influence of temperature

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14°C the reproductive behaviour was similar, both species needing over 2 months to mature. At 18°C, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias

Energy balance of mussels Mytilus galloprovincialis: the effect of length and age

Clearance and ingestion rates, absorption efficiencies and respiration rates were measured in mussels Mytilus galloprovincialis Lmk of different lengths (53 to 89 mm) and age (10 to 24 mo) from cultivation rafts in the Ría de Arosa (Galicia, Spain). The experiments were carried out either in the laboratory, using monoalgal food (Isochrysis galbana) with an organic content of 91%, or under natural conditions of food availability in cultivation rafts with seston, the organic content of which ranged from 33 to 69%. Food concentrations ranged from 0.57 to 1.00 mg l-1 of total particulate matter (TPM), a load which is below the threshold for the production of pseudofaeces in Mytilus. These experiments proved that the ingestion rate (IR = mg TPM h-1) of food increases with the size of the mussel (measured as g of soft-tissue dry weight [DW]) according to the power equation IR = 12.661DW0.619, this model accounting for over 90% of the variance of the IR. Behavioural patterns that tended to maintain constant IR regardless of the density of the food were observed. Absorption efficiency (AE) is positively related to the organic content (OC) of the food according to the following hyperbolic equation: AE = 1.015 - 0.163(1/OC) (r = 0.940). AE is independent of mussel size for most of the size range used in this study, but there is a critical length around 85 mm, above which there is a noticeable decrease of AE. Metabolic expenditure, measured in terms of oxygen consumption standarized per unit of dry weight of flesh, tends to increase with the age of the mussel. The results obtained led to the conclusion that physiological traits such as the regulation of ingestion or differences in AE between groups do not explain the differences in growth between mussels of the same age. These differences must therefore be due to the limited food and space available as a result of the large numbers of mussels on the cultivation rafts and the agglomeration of mussels on the cultivation ropes.Versión de editor

LA INSTRUCCIÓN PROGRAMADA REMOTA Y EL TUTORIAL COMO ESTRATEGIAS EN EL PROCESO DE APRENDIZAJE PARA EL DESARROLLO DE COMPETENCIAS MATEMÁTICAS.

The objective of the research is to determine the importance in the use of the remote programmed instruction and the tutorial as strategies in the learning process for the development of mathematical competences in students of the middle school of Educational Institutions of the District of Barranquilla, Colombia. Given the current situation of remote education caused by the pandemic Sars Cov 2 virus, known as Corona Virus, Covid 19, has had an impact on the fabric of human reality on a planetary level, especially because of the health conditions of communities at the local, regional, national and global levels, educational institutions as social organizations have thus migrated to a form of virtual study. In this sense, the role that the school plays in this current context, its teachers and parents have been decisive to face this formation from the home, where the technologies are the tools that allow to establish the direct connection with the students. Methodologically, the research was descriptive – Field, with a non-experimental, transactional design, with descriptive and inferential analysis. The population consisted of 140 eleventh-grade students. It was found that the eleventh grade students stood out in the high category, when it comes to using technological tools using the Remote Programmed Instruction (IPR) and the tutorial on solving mathematical problems. It is concluded that the use of technologies under the virtual remote modality promotes favorable results in the training of students. It is recommended to establish a curriculum and content in the area of mathematics adapted to learning strategies through remote programmed teaching.El objetivo de la investigación es determinar la importancia en el uso de la instrucción programada remota y del tutorial como estrategias en el proceso de aprendizaje para el desarrollo de competencias matemáticas en estudiantes de la media de Instituciones Educativas del Distrito de Barranquilla, Colombia. Dada la situación actual de una educación a distancia remota provocada por la pandemia del virus Sars Cov 2, conocido como Corona Virus, Covid 19, ha tenido un impacto en el tejido de la realidad humana a nivel planetario, sobre todo por las condiciones sanitarias que presentan las comunidades a nivel local, regional, nacional y mundial, en consecuencia, las instituciones educativas como organizaciones sociales han emigrado en estos tiempos a una modalidad de estudio virtual. En ese sentido, el papel que juega la escuela en este contexto actual, sus docentes y padres de familia ha sido determinante para enfrentar esta formación desde el hogar, donde las tecnologías son las herramientas que permiten establecer la conexión directa con los estudiantes. Metodológicamente, la investigación fue descriptiva – De campo, con un diseño no experimental, transaccional, con un análisis descriptivo e inferencial. La población estuvo constituida por 140 estudiantes de undécimo grado. Se encontró que los estudiantes de undécimo grado se destacaron en la categoría alta, cuando se trata de utilizar herramientas tecnológicas valiéndose de la Instrucción Programada Remota (IPR) y el tutorial en la resolución de problemas matemáticos. Se concluye que el empleo de las tecnologías bajo la modalidad remota virtual promueve resultados favorables en la formación del estudiantado. Se recomienda establecer un currículo y contenidos en el área de matemáticas ajustados a las estrategias de aprendizaje mediante la enseñanza programada remota

Characterization of plant growth promoting bacteria (PGPR) isolated from the rhizosphere of Arthrocnemum macrostachyum.

Motivation: The recent boom in organic agriculture has awakened the need to find alternative methods to chemical products. PGPRs (plant growth-promoting rhizobacteria) are rhizospheric bacteria that contribute in a favourable way for the plant development through different mechanisms like exudates production (that enhance plant rooting), nutrient solubilization or resistance to pathogenic agents (1). The study of these microorganisms and its subsequent use for different agriculture requirements is a viable option in order to get good results in a more sustainable way. In addition, it is an interesting approach to promote the soil regenerative abilities of some plants, like the halophyte Arthrocnemum macrostachyum (2).Methods: Bacteria from the rhizosphere of A. macrostachyum were isolated from plants grown in different areas at the Lebrija marshes. 5 µl of exponentially bacterial cultures were dropped onto Petri dishes containing different media: CAS to test siderophores production (3), PVK for phosphate solubilization (3), nutrient broth supplemented with NaCl for testing tolerance to sodium chloride and nutrient broth with 0,5mM and 1mM Zn concentrations to test heavy metal resistance. All of them were incubated at 28ºC for 72h. Acyl-homoserine lactone and indolacetic acid (IAA) production tests (3) were also performed. In addition, 5 µl droplets of each bacterial suspension were spotted on Petri dishes together with a disk of active Macrophomina phaseolina culture to test antifungal activity.Results: A total of 203 strains were isolated from the rhizosphere of A.macrostachyum plants. In CAS medium, 40% of them formed an orange-yellowish halo, denoting siderophore production. In PVK medium, 7% shown a transparent halo, indicating phosphate solubilization ability. 30% of the strains were auxin producers, while only a 13% exhibited the quorum sensing mechanism. 3% of all the strains displayed high halotolerance, showed positive growth in 24 % (p/v) NaCl. 5% and 3% of the strains were able to grow in the presence of 0,5 and 1 mM Zn, respectively. Taking into account fungicide activity, 11% of the bacterial isolates are able to inhibit the growth of the pathogenic fungus M. phaseolina.Conclusions: An earlier conclusion of this incipient study is that the rhizosphere of halophyte plants living in natural stressing areas is a good source for isolating bacteria with desirable properties to be used as PGPR and also for the control of pathogenic fungus

Impact of texture TDS and flavour TDS tasks and of chocolate-chip biscuit characteristics on oral processing features

[EN] The objective of the present study was to investigate differences in oral activity when biscuits of the same type but with subtle composition differences are consumed and how performing a Temporal Dominance of Sensations (TDS) task modifies the way one eats. In addition, comparisons were made between performing a texture TDS (T-TDS) and a flavour TDS (F-TDS). Oral activity while eating biscuits with and without conducting a TDS task was recorded using a 3.dimensional motion capture system to monitor the evolution of jaw movements. The results showed that oral activity evolved over the consumption time, differed depending on the texture of the sample and was affected to a small but significant extent when a TDS task was performed simultaneously (the differences averaged < 4 cycles, 1 s in duration, 0.1 cycles/s in frequency, and 1 mm in lateral displacement). The biscuit samples were affected equally. Almost no differences were found on comparing oral activity during the execution of the T-TDS and the F-TDS tasks. Overall, the present results show differences in oral activity even for food products of the same category with subtle differences in composition. Performing TDS tasks (regardless of their modality) during sample consumption affected the total number, frequency and lateral amplitude of the chewing movements which should be taken into account for future research. However, these differences were small and affected both samples equally.The authors are grateful to the Spanish Ministry of the Economy and Competitiveness (AGL-2016-75403-R, Spain) and to the Regional Government of Valencia (Project Prometeo 2017/189, Spain) for financial support.Rizo, A.; Jimenez-Pérez, I.; Camacho-García, A.; Fiszman, S.; Pérez-Soriano, P.; Tarrega, A. (2019). Impact of texture TDS and flavour TDS tasks and of chocolate-chip biscuit characteristics on oral processing features. Food Quality and Preference. 76:109-117. https://doi.org/10.1016/j.foodqual.2019.04.005S1091177

Dynamics of biochemical components, lipids classes and energy values on gonadal development of R.philippinarum associated with the temperature and ingestion rate

This study evaluates the effect of temperature, coupled with ingestion rate, on the dynamics of biochemical components and lipid classes in R. philippinarum. The data are discussed with regard to sexual development and energy balance. Experimental protocol developed in the present study used two groups of the clam R. philippinarum: L (temperatures of 14 °C and 18 °C) and H (temperatures of 18 °C and 22 °C). The intra-group ingestion level was similar, although the ingestion level of the clams in the group H was 2.4 times higher than group L. We observed that R. philippinarum conditioned at 18 °C (18L) shows higher protein content, furthermore an important loss of organic weight was observed after 48 days. In such a situation, the clams use their own reserves (carbohydrates and glycogen) for sexual development while in situations without food stress (positive energy balance) and low temperature (14 °C) an accumulation of reserves is produced. Strikingly dissimilar behaviour in biochemical composition was observed for the 18H and 22H treatments, both with a positive energy balance. Despite similar protein content, the highest levels of carbohydrates were observed at the lower temperature (18 °C). Glycogen was also higher for the 18 °C treatment, although the differences were significant only in the males. Although the total lipids in R. philippinarum showed no significant differences in any treatment, they became apparent and related to sex when considering the individual lipid classes. There was no variation in lipid classes in the males between the 14L and 22H treatments despite the large disparity in the degree of sexual development. However, in the females significant differences in lipid classes (phospholipids, triglycerides) were observed. The results of this study show that a positive energy balance permits R. philippinarum gonadal development and accumulation of reserves both in low and high temperature conditions. In low temperature situations, gonadal development is slower and the energy reserves are accumulated in the form of carbohydrates. When the clams are conditioned at high temperatures, gonadal development is fast and complete, carbohydrates are consumed and lipids are accumulated.Publicado

Estudio de la temperatura del suelo en Puerto Rico.

Soil temperature measurements from a climate monitoring network in Puerto Rico were evaluated and the difference between mean summer and mean winter soil temperature, known as isotivity value, was calculated. Air and soil temperature was collected from five weather stations of the USDA-Natural Resources Conservation Service from sea level to 1,019 m above sea level and from different soil moisture regimes. Isotivity values ranged from 1.2 to 3.9° C with an average of 2.6° C. The 750-m elevation was identified as the limit between the isohyperthermic and isothermic soil temperature regimes in the perudic soil moisture regime in Puerto Rico. The greatest differences between mean annual soil temperature and mean annual air temperature were observed at Guánica, Combate and Guilarte (2.1 ° C) stations. The smallest differences were observed at Maricao (0.8° C) and Isabela (1.8° C) stations. The study also indicated that the mean annual soil temperature in Puerto Rico can be estimated by adding 1.8° C to the mean annual air temperature or by the equation y = -0.007x + 28.0° C. The equation indicates that 97 percent of the time the behavior of the mean annual soil temperature is a function of elevation. According to the updated soil temperature regime boundaries, eight soil series were established in the Soil Survey of San Germán Area. In an area under the isothermic soil temperature regime, four soil series were classified as Oxisols (Haploperox), two soil series as Inceptisols (Eutrudepts) and two soil series as Mollisols (Argiudolls). This is the first field recognition of the Haploperox soil great group in the United States and its territories.Se evaluaron mediciones de temperatura del suelo de la red de monitoreo de clima en Puerto Rico y se calculó la diferencia entre la temperatura promedio del suelo de verano y de invierno, conocida como valor de isotividad. Se tomaron datos de temperatura del aire y del suelo de cinco estaciones climatológicas del Servicio de Conservación de Recursos Naturales del Departamento de Agricultura de los Estados Unidos desde el nivel del mar hasta 1,019 m de elevación sobre el nivel del mar y a diferentes regímenes de humedad del suelo. Los valores de isotividad oscilaron entre 1.2 y 3.9° C con una media de 2.6° C. El límite entre el régimen de temperatura de suelo isohipertérmico e isotérmico en el régimen de humedad perúdico en Puerto Rico fue identificado a una elevación de 750 m. En las estaciones de Guánica, Combate y Guilarte se observaron las mayores diferencias entre la media anual de la temperatura del suelo y la media anual de la temperatura del aire (2.1° C). En las estaciones de Maricao (0.8° C) e Isabela (1.8° C) se observaron las menores diferencias. El estudio también indica que la media anual de la temperatura del suelo en Puerto Rico puede ser estimada añadiéndole 1.8° C a la media anual de la temperatura del aire o por la ecuación y = -0.007x + 28.0° C. La ecuación indica que el 97 por ciento del tiempo el comportamiento de la media anual de la temperatura del suelo es una función de la elevación. De acuerdo con la actualización de los límites de los regímenes de temperatura de suelo, se establecieron ocho series de suelo en el Catastro de Suelos del Área de San Germán. Cuatro series de suelo clasificaron como Oxisoles (Haploperox), dos series de suelos como Inceptisoles (Eutrudepts) y dos series de suelos como Molisoles (Argiudolls) en el área bajo régimen de temperatura isotérmico. Este es el primer reconocimiento en el campo del gran grupo de suelos Haploperox en los Estados Unidos de América y sus territorios