The ecology of the Mar Menor coastal lagoon: A fast changing ecosystem under human pressure

The Mar Menor is a hypersaline coastal lagoon, with a surface area of 135 km2 and a perimeter of 59.51 km. It is located on the southwestern Mediterranean coastline (3742′00′′N, 0047′00′′W) with a mean depth of 3.6 m and a maximum depth of 6 m. “La Manga,” a sandy bar 22 km long and 100–900 m wide, acts as a barrier between the lagoon and the Mediterranean Sea. It is crossed by five more or less functional inlets called golas. Four are shallow (less than 1 m deep) and one of them, El Estacio, was widened and dug to a 5-m depth to make it a navigational channel. Altogether a total width of lagoon entrances is about 645 m, giving Mar Menor a restriction ratio of 0.015. Mar Menor is therefore a restricted lagoon according to the classification proposed by Kjerfve1 (see Chapter 6). There are two main islands and three other smaller islands, one of which is artificially connected to La Manga

TÉCNICAS DE RECOLECCIÓN Y ESTUDIO EN LA CLASE HOLOTHUROIDEA. 1. GENERALIDADES, SISTEMÁTICA, ECOLOGÍA, BIOLOGÍA Y COMPORTAMIENTO

Studies about holothunans in Spain are scarce and they are reduced to some faunistic or systematic notes. In this paper some of the methods habitually employed in the different aspects of the systematic (sampling and preservation, preparation of spicules. calcareous ring, etc.), biological (reproduction, development, growth, nutrition and activity) and ecological (evaluation of the populations, incidence of the environmental factors) studies of this group of echinoderms are presented.En España los estudios sobre las holoturias son escasos y se reducen a algunas notas faunísticas o sistemáticas. En este trabajo se presentan algunas de las técnicas empleadas habitualmente por los investigadores en los distintos aspectos de la sistemática (recolección y conservación, preparación de espículas, anillo calcáreo, etc.), biología (reproducción, desarrollo, crecimiento, nutrición, actividad) y ecología (evaluación de las poblaciones. incidencia de los factores ambientales) de este grupo de equinodermos

Estudio de la carga interna en pádel amateur mediante la frecuencia cardíaca

Los objetivos de este estudio fueron evaluar el nivel de condición física de 8 sujetos amateur de pádel, definir su perfil energético de esfuerzo en juego real mediante registro de frecuencia cardíaca (FC), y proponer un conjunto de variables justificadas de esta, que permita analizar el perfil de carga interna en pádel. Mediante prueba de esfuerzo incremental máxima en cinta de correr se obtuvieron parámetros ergoespirométricos, respiratorios y sus equivalentes cardíacos, introducidos en el sistema de registro de la FC Polar Team. Los sujetos disputaron 7 partidos de entrenamiento de 1 hora de duración y 72-96 horas de separación entre ellos, obteniéndose como variables: consumo máximo de oxígeno (VO2 máx) y porcentaje (%) de VO2 máx en el umbral anaeróbico; en prueba de esfuerzo, FC máx., media y mín., y zonas de trabajo metabólicas (rangos de FC). Los resultados presentan VO2 máx de 51,15 ± 5,73 ml · kg–1 · min–1, FC máx. durante el juego de 154,75 ± 7,25 ppm, FC med de 130,0 ± 10,4 ppm para tiempo de juego y 89,75 % del tiempo de juego en zona de trabajo aeróbica. Como conclusión, el esfuerzo al que son sometidos durante el juego a nivel cardiorrespiratorio los jugadores amateur de pádel se basa casi exclusivamente en metabolismos aeróbicos. Además, las variables máx., mín. y media de FC para tiempos de juego y descanso y el establecimiento de zonas de trabajo de FC pueden aportarnos información importante sobre lo que ocurre en el juego a nivel cardiorrespiratorio

Evidence of a planktonic food web response to changes in nutrient input dynamics in the Mar Menor coastal lagoon, Spain

Nutrient input dynamics in the Mar Menor coastal lagoon has recently changed as a consequence of changes in agricultural practises. An interannual comparison of the environmental variables and the planktonic biomass size-spectra was performed between 1988 and 1997. While nitrate concentration was low in 1988, the values in 1997 increased considerably. Since 1995, two alloctonous jellyfish species (Rhyzostoma pulmo and Cotylorhiza tuberculata) occurred in large numbers in summer time and reached peak abundance in summer of 1997. The size-spectra analysis comparison revealed that, in spite of changes in nutrient input that stimulated the growth of larger phytoplankton cells, there were no significant differences in the spectra slope which followed a similar seasonal trend in both years. However, the plankton biovolume considered under the size range compared (between 2 and 1000 µm diameter) was, paradoxically, always lower in 1997. Given that there were higher nutrient levels in 1997, this finding suggest a strong top-down control mechanism of size structure. Gut contents of jellyfishes showed their preference for large diatoms, tintinnids, veliger larvae and copepods, corroborating that size structure in these assemblages can be subject to top-down control. The implication of these results is that the feeding activities of large gelatinous zooplankton (jellyfishes) may play an important role controlling the consequences of eutrophication within the Mar Menor coastal lagoon

Effect of an Acute Exercise Until Exhaustion on the Serum and Urinary Concentrations of Cobalt, Copper, and Manganese Among Well-Trained Athletes

The current information about the effect of physical exercise on the body concentrations of several minerals is still limited, both in the acute (short-term) and adaptive (long-term) responses. So, this manuscript aims, on the one hand, to assess the possible differences on basal levels of cobalt (Co), copper (Cu), and manganese (Mn) concentrations in serum and urine between athletes and sedentary participants and, on the other hand, to evaluate the effect of an acute progressive physical exercise until voluntary exhaustion on the serum and urinary concentrations of Co, Cu, and Mn. Two groups participated in this survey, one was formed by untrained, sedentary males (CG; n = 26), and the other group was constituted by national endurance (long and middle distances) athletes (AG; n = 21). All participants were from the same region of Spain. Participants of both groups performed a physical test on a treadmill, reaching voluntary exhaustion. Blood and urine samples of each participant were collected before and at after the tests. Once obtained and processed, the concentrations of Co, Cu, and Mn elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The differences in the studied variables were evaluated using a mixed model by means of an ANOVA and Bonferroni post hoc tests. In the comparison of the pre-test values between groups, the results showed that serum concentrations of Mn were significantly lower in CG than in AG (p < 0.01). In urine, Co and Mn levels were significantly higher among CG participants (p < 0.01) than among AG ones, while in the case of Cu, the values were lower (p < 0.01) in the CG than in the AG. Regarding the effects of the effort tests, no significant changes were found among the participants of the CG. It was observed that the serum concentrations of Co (p < 0.05) and Cu (p < 0.01) decreased after the test among the AG participants. Also, the results showed that there were no statistical differences in Co and Mn values (expressed in μg/g creatinine). However, the urinary post-test Cu concentrations were lower (p < 0.05) among AG participants. In basal conditions, serum concentrations of Mn were significantly lower in CG than in AG. In urine, Co and Mn levels were significantly higher among CG participants and Cu level was significantly lower in CG, a fact which may reflect adaptive responses to exercise. An incremental exercise to exhaustion in AG produces a decrease in Co and Cu serum concentrations, as well as in urinary excretion of Cu

Correction to: Erythrocyte concentrations of chromium, copper, manganese, molybdenum, selenium and zinc in subjects with different physical training levels

Correction to: J Int Soc Sports Nutr 17, 35 (2020) https://doi.org/10.1186/s12970-020-00367-

Efectos de un programa de actividad física sobre la condición física en mujeres premenopáusicas

Esta investigación pretende conocer los cambios que provoca un programa de actividad física moderada de 5 meses de duración sobre la condición física (fuerza, flexibilidad y resistencia) en mujeres premenopáusicas. En el estudio participaron mujeres premenopáusicas, separadas en dos grupos: menores de 35 años (n = 10) y mayores de 35 años (n = 10). Para el estudio, se estableció un programa de intervención de aeróbic, clases de step y tonificación, de 5 meses de duración, con una frecuencia semanal de 3 días alternos y con una duración de 60 minutos cada sesión a una intensidad entre el 60-70 % de la frecuencia cardíaca máxima de reserva. Los resultados muestran que las mujeres de menor edad, al finalizar el programa de actividad física, incrementaron la flexibilidad posterior del tronco, la fuerza de prensión de ambas manos, aunque solo mejoraron de forma significativa la flexibilidad anterior del tronco (p

Influence of a physical exercise until exhaustion in normothermic and hyperthermic conditions on serum, erythrocyte and urinary concentrations of magnesium and phosphorus

Aim: The aim of this study was to evaluate the effect of the performance of a maximal exercise test until exhaustion in normothermic and hyperthermic conditions on body concentrations of magnesium (Mg) and phosphorus (P). Methods: 19 adult males (age: 22.58 ± 1.05 years) performed two maximum incremental exercise tests on a cycloergometer separated by 48 h. The first was performed in normothermia (22 ± 2 °C) and the second in hyperthermic conditions induced with a sauna (42 ± 2 °C). Blood and urine samples were taken before and after each test. Results: The tests in hyperthermia did not produce ergospirometric alterations or a noticeable cardiovascular drift. Serum Mg concentrations underwent a reduction after the stress test in hyperthermia (p > 0.05) but not in normothermia. Nevertheless, urinary and erythrocyte concentrations of Mg, and urinary, erythrocyte and serum concentrations of P did not undergo alterations in either conditions. Conclusions: It seems that exercise in hyperthermic conditions induces a tissue redistribution of Mg in the body, a fact which was not observed in normothermic conditions

Two-step ATP-driven opening of cohesin head.

The cohesin ring is a protein complex composed of four core subunits: Smc1A, Smc3, Rad21 and Stag1/2. It is involved in chromosome segregation, DNA repair, chromatin organization and transcription regulation. Opening of the ring occurs at the “head” structure, formed of the ATPase domains of Smc1A and Smc3 and Rad21. We investigate the mechanisms of the cohesin ring opening using techniques of free molecular dynamics (MD), steered MD and quantum mechanics/molecular mechanics MD (QM/MM MD). The study allows the thorough analysis of the opening events at the atomic scale: i) ATP hydrolysis at the Smc1A site, evaluating the role of the carboxy-terminal domain of Rad21 in the process; ii) the activation of the Smc3 site potentially mediated by the movement of specific amino acids; and iii) opening of the head domains after the two ATP hydrolysis events. Our study suggests that the cohesin ring opening is triggered by a sequential activation of the ATP sites in which ATP hydrolysis at the Smc1A site induces ATPase activity at the Smc3 site. Our analysis also provides an explanation for the effect of pathogenic variants related to cohesinopathies and cancer.post-print4709 K

Arterial oxygen desaturation in pre- and post-menopausal women during aerobic exercise

La pulsioximetría ha sido validada como una técnica muy fiable para valorar de forma no invasiva la saturación arterial. Nos proponemos estudiar qué variaciones sufren los niveles de SaO2 durante la realización de ejercicio aeróbico en distintos grupos de mujeres: pre y postmenopáusicas. Para ello clasificaremos las desaturaciones en leves, moderadas y graves. Contamos con la participación consentida y voluntaria de 31 mujeres sedentarias, divididas en dos grupos: pre y postmenopáusicas. Valoramos la SaO2 a lo largo de una sesión de 60 minutos de aeróbic, cada 15 minutos, determinando el nivel de desaturación de cada participante. En reposo no encontramos diferencias significativas en los niveles de SaO2 entre ambos grupos, mientras que durante el ejercicio la frecuencia con la que encontramos SaO2 normales es del 92,3% en pre y del 66,7% en postmenopáusicas. Las desaturaciones leves aparecen con una frecuencia del 7,7% en pre y del 27,8% en postmenopáusicas, mientras que las desaturaciones moderadas tan sólo se observan en menopáusicas (5,6%). Como conclusiones, podemos afirmar que durante la realización de ejercicio aeróbico, es mayor el número de desaturaciones que sufren las mujeres postmenopáusicas, frente a las mujeres premenopáusicas. La pulsioximetría y la valoración de la SaO2 pueden ser una herramienta útil al trabajar con mujeres postmenopáusicas, que sufren más desaturaciones, para: detectar intensidades elevadas cuando no se disponen de otros medios, por su relación con la producción de lactato, así como por tratarse de una técnica muy sencilla y no invasiva.Actividad Física y DeporteMedicin