Tracking the Development of Muscular Myoglobin Stores in Mysticete Calves

For marine mammals, the ability to tolerate apnea and make extended dives is a defining adaptive trait, facilitating the exploitation of marine food resources. Elevated levels of myoglobin within the muscles are a consistent hallmark of this trait, allowing oxygen collected at the surface to be stored in the muscles and subsequently used to support extended dives. In mysticetes, the largest of marine predators, details on muscular myoglobin levels are limited. The developmental trajectory of muscular myoglobin stores has yet to be documented and any physiological links between early behavior and the development of muscular myoglobin stores remain unknown. In this study, we used muscle tissue samples from stranded mysticetes to investigate these issues. Samples from three different age cohorts and three species of mysticetes were included (total sample size = 18). Results indicate that in mysticete calves, muscle myoglobin stores comprise only a small percentage (17–23%) of conspecific adult myoglobin complements. Development of elevated myoglobin levels is protracted over the course of extended maturation in mysticetes. Additionally, comparisons of myoglobin levels between and within muscles, along with details of interspecific differences in rates of accumulation of myoglobin in very young mysticetes, suggest that levels of exercise may influence the rate of development of myoglobin stores in young mysticetes. This new information infers a close interplay between the physiology, ontogeny and early life history of young mysticetes and provides new insight into the pressures that may shape adaptive strategies in migratory mysticetes. Furthermore, the study highlights the vulnerability of specific age cohorts to impending changes in the availability of foraging habitat and marine resources

Analysis of sediments carried by a tropical intertidal sea cucumber, Holothuria inornata

On the Pacific coast of Costa Rica, the sea cucumber Holothuria inornata is typically found covered by natural sediments acquired from its surroundings in the rocky intertidal zone. Very little is known about this behavior, and even the most basic data about how much and what kinds of sediments are carried are unknown. We examined the composition of substrate on individuals captured at San Miguel Biological Station in Cabo Blanco Absolute Reserve, Costa Rica in order to learn more about this understudied behavior. We collected 30 individuals ranging from 94-193 mm in length at low tide from June- July 2012. At the time of capture, all sea cucumbers were entirely covered by sediments tightly adhered to the back of the animal. We removed the sediments from the back of each sea cucumber, dried the sediments, sorted them according to material, and weighed them. H. inornata at this location carried shell fragments, pebbles, sand, and other small items. The dry weight of sediments carried by an individual sea cucumber reached a maximum of 23.7 g. The mean composition BY WEIGHT of sediments, taking into account the three principal sediment types, was 45% shell, 30% pebble, and 25% sand, although individual compositions varied greatly (16.0-67.4% shell; 0.8-69.0% pebble; 11.4-69.1% sand). A simulation model showed that this degree of variation is not expected from random selection of sediment; the sea cucumbers exhibited individual selectivity. Background sediment composition was assessed by random point sampling in the field. The composition of sediments in the field with 95% confidence intervals, taking into account the three principle sediment types, was 24% (19.74-28.81%) shell, 38% (33.02-43.26%) pebble, and 38% (33.02-43.26%) sand. The difference between environmental composition and average composition carried by sea cucumbers is further evidence that sea cucumbers may be exhibiting some degree of selectivity

Depresión en adultos mayores del municipio de Mochitlán, Guerrero (México)

Introducción: La depresión en adultos mayores es un tema importante debido a que afecta de manera significativa la salud y calidad de vida. A medida que las personas envejecen, pueden experimentar cambios físicos, emocionales y sociales que los hacen más susceptibles a tener depresión. La Organización Mundial de la Salud (OMS) estima que entre 2015 y 2050 la población mundial mayor de 60 años pasará del 12% al 22% de padecer algún síntoma depresivo. Objetivo: Identificar la prevalencia y factores asociados a la depresión en adultos mayores del Municipio de Mochitlán, Guerrero. Materiales y métodos: Investigación mixta, cuantitativa con diseño transversal analítico, muestreo aleatorio simple en una población de 26 adultos mayores, se recabo información mediante una encuesta aplicada por los investigadores con opción múltiple utilizando un instrumento de cuatro apartados. Para el enfoque cualitativo se utilizó el método etnográfico, mediante una entrevista semiestructurada con 3 preguntas abiertas a un grupo focal de siete adultos mayores. Resultados: Se encontró depresión leve (38,46%), moderada (7,69%) y grave (3,85%). Los factores asociados fueron género femenino, tipo de trabajo; ingreso mensual. El análisis cualitativo mostro emociones positivas y negativas. Conclusiones: 50% de la población presento algún tipo de depresión

Tracking the Development of Muscular Myoglobin Stores in Mysticete Calves.

For marine mammals, the ability to tolerate apnea and make extended dives is a defining adaptive trait, facilitating the exploitation of marine food resources. Elevated levels of myoglobin within the muscles are a consistent hallmark of this trait, allowing oxygen collected at the surface to be stored in the muscles and subsequently used to support extended dives. In mysticetes, the largest of marine predators, details on muscular myoglobin levels are limited. The developmental trajectory of muscular myoglobin stores has yet to be documented and any physiological links between early behavior and the development of muscular myoglobin stores remain unknown. In this study, we used muscle tissue samples from stranded mysticetes to investigate these issues. Samples from three different age cohorts and three species of mysticetes were included (total sample size = 18). Results indicate that in mysticete calves, muscle myoglobin stores comprise only a small percentage (17-23%) of conspecific adult myoglobin complements. Development of elevated myoglobin levels is protracted over the course of extended maturation in mysticetes. Additionally, comparisons of myoglobin levels between and within muscles, along with details of interspecific differences in rates of accumulation of myoglobin in very young mysticetes, suggest that levels of exercise may influence the rate of development of myoglobin stores in young mysticetes. This new information infers a close interplay between the physiology, ontogeny and early life history of young mysticetes and provides new insight into the pressures that may shape adaptive strategies in migratory mysticetes. Furthermore, the study highlights the vulnerability of specific age cohorts to impending changes in the availability of foraging habitat and marine resources

RiceJimMarineMammalInstitTrackingDevelopmentuscular.pdf

For marine mammals, the ability to tolerate apnea and make extended dives is a defining adaptive trait, facilitating the exploitation of marine food resources. Elevated levels of myoglobin within the muscles are a consistent hallmark of this trait, allowing oxygen collected at the surface to be stored in the muscles and subsequently used to support extended dives. In mysticetes, the largest of marine predators, details on muscular myoglobin levels are limited. The developmental trajectory of muscular myoglobin stores has yet to be documented and any physiological links between early behavior and the development of muscular myoglobin stores remain unknown. In this study, we used muscle tissue samples from stranded mysticetes to investigate these issues. Samples from three different age cohorts and three species of mysticetes were included (total sample size = 18). Results indicate that in mysticete calves, muscle myoglobin stores comprise only a small percentage (17–23%) of conspecific adult myoglobin complements. Development of elevated myoglobin levels is protracted over the course of extended maturation in mysticetes. Additionally, comparisons of myoglobin levels between and within muscles, along with details of interspecific differences in rates of accumulation of myoglobin in very young mysticetes, suggest that levels of exercise may influence the rate of development of myoglobin stores in young mysticetes. This new information infers a close interplay between the physiology, ontogeny and early life history of young mysticetes and provides new insight into the pressures that may shape adaptive strategies in migratory mysticetes. Furthermore, the study highlights the vulnerability of specific age cohorts to impending changes in the availability of foraging habitat and marine resources

RiceJimMarineMammalInstitTrackingDevelopmentuscular(Table S1).pdf

For marine mammals, the ability to tolerate apnea and make extended dives is a defining adaptive trait, facilitating the exploitation of marine food resources. Elevated levels of myoglobin within the muscles are a consistent hallmark of this trait, allowing oxygen collected at the surface to be stored in the muscles and subsequently used to support extended dives. In mysticetes, the largest of marine predators, details on muscular myoglobin levels are limited. The developmental trajectory of muscular myoglobin stores has yet to be documented and any physiological links between early behavior and the development of muscular myoglobin stores remain unknown. In this study, we used muscle tissue samples from stranded mysticetes to investigate these issues. Samples from three different age cohorts and three species of mysticetes were included (total sample size = 18). Results indicate that in mysticete calves, muscle myoglobin stores comprise only a small percentage (17–23%) of conspecific adult myoglobin complements. Development of elevated myoglobin levels is protracted over the course of extended maturation in mysticetes. Additionally, comparisons of myoglobin levels between and within muscles, along with details of interspecific differences in rates of accumulation of myoglobin in very young mysticetes, suggest that levels of exercise may influence the rate of development of myoglobin stores in young mysticetes. This new information infers a close interplay between the physiology, ontogeny and early life history of young mysticetes and provides new insight into the pressures that may shape adaptive strategies in migratory mysticetes. Furthermore, the study highlights the vulnerability of specific age cohorts to impending changes in the availability of foraging habitat and marine resources

RiceJimMarineMammalInstitTrackingDevelopmentuscular(Table S2).pdf

For marine mammals, the ability to tolerate apnea and make extended dives is a defining adaptive trait, facilitating the exploitation of marine food resources. Elevated levels of myoglobin within the muscles are a consistent hallmark of this trait, allowing oxygen collected at the surface to be stored in the muscles and subsequently used to support extended dives. In mysticetes, the largest of marine predators, details on muscular myoglobin levels are limited. The developmental trajectory of muscular myoglobin stores has yet to be documented and any physiological links between early behavior and the development of muscular myoglobin stores remain unknown. In this study, we used muscle tissue samples from stranded mysticetes to investigate these issues. Samples from three different age cohorts and three species of mysticetes were included (total sample size = 18). Results indicate that in mysticete calves, muscle myoglobin stores comprise only a small percentage (17–23%) of conspecific adult myoglobin complements. Development of elevated myoglobin levels is protracted over the course of extended maturation in mysticetes. Additionally, comparisons of myoglobin levels between and within muscles, along with details of interspecific differences in rates of accumulation of myoglobin in very young mysticetes, suggest that levels of exercise may influence the rate of development of myoglobin stores in young mysticetes. This new information infers a close interplay between the physiology, ontogeny and early life history of young mysticetes and provides new insight into the pressures that may shape adaptive strategies in migratory mysticetes. Furthermore, the study highlights the vulnerability of specific age cohorts to impending changes in the availability of foraging habitat and marine resources

Sampling sites used for the provision of muscle tissue samples from mysticetes.

<p>(based on Polasek and Davis [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145893#pone.0145893.ref043" target="_blank">43</a>]). Picture credit: Yvette Hansen.</p

Early ontogeny of Mb levels in three species of mysticetes.

<p>Calf age classes based on growth curves described by ^a [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145893#pone.0145893.ref044" target="_blank">44</a>], ^b [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145893#pone.0145893.ref045" target="_blank">45</a>] and ^c [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145893#pone.0145893.ref046" target="_blank">46</a>], along with additional information from the field site of the necropsy. Estimated ages: Neonates < 2 weeks, young calves between 2 weeks to 3 months and stranded in breeding areas, migrating calves between 3 to 5 months and stranded in migratory corridors. Levels of Mb in the neonate minke whale lay beyond the upper limits of the 95% confidence interval for mean Mb levels in neonate humpback and gray whale calves (4.2 mg Mb g^-1 vs. 0.0<1.5<3.0 mg Mb g^-1). Levels of Mb rose faster in humpback vs. gray whale calves between the neonate, young and migratory age classes (for humpback whales β = 0.98 and for gray whales β = 0.41). Error bars indicate S.D.</p

The development trajectory of muscular Mb levels in three species of mysticetes.

<p>Differences between age classes and between species were significant (GLM; for age class ANOVA F₂ = 25.532, p = 0.000, for species ANOVA F ₂ = 5.671, p = 0.018). Error bars indicate +/- 1 S.E.</p