3 research outputs found
Spatial distribution patterns and movements of Holothuria arguinensis in the Ria Formosa (Portugal)
Holothurian populations are under pressure worldwide because of increasing demand for beche-de-mer, mainly
for Asian consumption. Importations to this area from new temperate fishing grounds provide economic opportunities
but also raise concerns regarding future over-exploitation. Studies on the habitat preferences and movements
of sea cucumbers are important for the management of sea cucumber stocks and sizing of no-take zones,
but information on the ecology and behavior of temperate sea cucumbers is scarce. This study describes the
small-scale distribution and movement patterns of Holothuria arguinensis in the intertidal zone of the Ria Formosa
national park (Portugal).Mark/recapture studieswere performed to record theirmovements over time on different
habitats (sand and seagrass). H. arguinensis preferred seagrass habitats and did not show a size or life
stage-related spatial segregation. Its density was 563 ind. haâ1 and mean movement speed was 10 m per day.
Movement speed did not differ between habitats and the direction of movement was offshore during the day
and shoreward during the night. Median home range size was 35 m2 and overlap among home ranges was
84%. H. arguinensis' high abundance, close association with seagrass and easy catchability in the intertidal zone,
indicate the importance of including intertidal lagoons in future studies on temperate sea cucumber ecology
since those systems might require different management strategies than fully submerged habitats
Clinical and molecular characterization of a cardiac ryanodine receptor founder mutation causing catecholaminergic polymorphic ventricular tachycardia
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a difficult-to-diagnose cause of sudden cardiac death (SCD). We identified a family of 1400 individuals with multiple cases of CPVT, including 36 SCDs during youth. Objectives We sought to identify the genetic cause of CPVT in this family, to preventively treat and clinically characterize the mutation-positive individuals, and to functionally characterize the pathogenic mechanisms of the mutation. Methods Genetic testing was performed for 1404 relatives. Mutation-positive individuals were preventively treated with ÎČ-blockers and clinically characterized with a serial exercise treadmill test (ETT) and Holter monitoring. In vitro functional studies included caffeine sensitivity and store overloadâinduced calcium release activity of the mutant channel in HEK293 cells. Results We identified the p.G357S_RyR2 mutation, in the cardiac ryanodine receptor, in 179 family members and in 6 SCD cases. No SCD was observed among treated mutation-positive individuals over a median follow-up of 37 months; however, 3 relatives who had refused genetic testing (confirmed mutation-positive individuals) experienced SCD. Holter monitoring did not provide relevant information for CPVT diagnosis. One single ETT was unable to detect complex cardiac arrhythmias in 72% of mutation-positive individuals, though the serial ETT improved the accuracy. Functional studies showed that the G357S mutation increased caffeine sensitivity and store overloadâinduced calcium release activity under conditions that mimic catecholaminergic stress. Conclusion Our study supports the use of genetic testing to identify individuals at risk of SCD to undertake prophylactic interventions. We also show that the pathogenic mechanisms of p.G357S_RyR2 appear to depend on ÎČ-adrenergic stimulation
Phosphoglucose isomerase variability of Cerastoderma glaucum as a model for testing the influence of environmental conditions and dispersal patterns through quantitative ecology approaches
Extreme conditions of coastal lagoons could directly modify the genetic patterns of species.
The aim of this work was to investigate the influence of environmental conditions and
small scale dispersal patterns on the phosphoglucose isomerase (PGI*) genetic variability of
Cerastoderma glaucum from the Mar Menor coastal lagoon. For this purpose, 284 cockles
were collected around the perimeter of the lagoon. Vertical polyacrylamide gel electrophoresis
was used to scan for PGI* polymorphisms, giving a total of seven alleles. The
spatial genetic distribution of the PGI* variability, which seems to be marked by the main
circulation in the lagoon, discriminates four hydrological basins. In the central basin,
a gradient of allelic composition reflects the circulation forced by the dominant winds and
the main channel communicated to the open sea. This result is well supported by the
salinity GAM model that defines this gradient.
The other three basins are defined by the distribution of fine sand in a more complex
model that tries to explain the isolation of the three sites localized inside these basins. The
southern, western and northern basins show the lowest degree of interconnection and are
considered the most confined areas of the Mar Menor lagoon. This situation agrees with
the confinement theory for benthic assemblages in the lagoon. The greater degree of
differentiation seen in the Isla del Ciervo population is probably due to recent human
intervention on the nearby Marchamalo channel, which has been drained in recent years
thus altering the influence of the Mediterranean Sea on the southern basin