RESUMEN
Morphological similarities between skates of the genus Dipturus in the north-eastern Atlantic and Mediterranean have resulted in longstanding confusion, misidentification and misreporting. Current evidence indicates that the common skate is best explained as two species, the flapper skate (Dipturus intermedius) and the common blue skate (D. batis). However, some management and conservation initiatives developed prior to the separation continue to refer to common skate (as 'D. batis'). This taxonomic uncertainty can lead to errors in estimating population viability, distribution range, and impact on fisheries management and conservation status. Here, we demonstrate how a concerted taxonomic approach, using molecular data and a combination of survey, angler and fisheries data, in addition to expert witness statements, can be used to build a higher resolution picture of the current distribution of D. intermedius. Collated data indicate that flapper skate has a more constrained distribution compared to the perceived distribution of the 'common skate', with most observations recorded from Norway and the western and northern seaboards of Ireland and Scotland, with occasional specimens from Portugal and the Azores. Overall, the revised spatial distribution of D. intermedius has significantly reduced the extant range of the species, indicating a possibly fragmented distribution range.
Asunto(s)
Rajidae , Animales , Rajidae/anatomía & histología , Irlanda , Portugal , Escocia , Explotaciones PesquerasRESUMEN
Using national and international research survey data and applying a combination of models and mapping tools, this study revealed temperature and depth as the crucial environmental drivers of both the distribution and the abundance of four benthopelagic chondrichthyans inhabiting Norwegian and Icelandic waters: rabbitfish (Chimaera monstrosa), velvet-belly lanternshark (Etmopterus spinax), blackmouth catshark (Galeus melastomus) and spurdog (Squalus acanthias). C. monstrosa and E. spinax seem to prefer similar spatial and ecological habitats, that is deep and cold waters. In contrast, G. melastomus and S. acanthias both prefer similar ecological habitats, that is warmer and shallower waters; nonetheless, they exhibit a different spatial distribution pattern. The species' varied habitat and spatial preferences may lead to different levels of exposure to fishing activities and associated by-catch risks. Findings of the species' spatial distributions and their driving forces are expected to inform the sustainable management of these species and the ecosystems they inhabit.
Asunto(s)
Tiburones , Animales , Quimera , Ecosistema , Noruega , TemperaturaRESUMEN
With just a handful of documented cases of hybridisation in cartilaginous fishes, shark hybridisation remains poorly investigated. Small amounts of admixture have been detected between Galapagos (Carcharhinus galapagensis) and dusky (Carcharhinus obscurus) sharks previously, generating a hypothesis of ongoing hybridisation. We sampled a large number of individuals from areas where the species co-occur (contact zones) across the Pacific Ocean and used both mitochondrial and nuclear-encoded SNPs to examine genetic admixture and introgression between the two species. Using empirical analytical approaches and simulations, we first developed a set of 1873 highly informative SNPs for these two species to evaluate the degree of admixture between them. Overall, results indicate a high discriminatory power of nuclear SNPs (FSTâ¯=â¯0.47, pâ¯<â¯0.05) between the two species, unlike mitochondrial DNA (ΦSTâ¯=â¯0.00 pâ¯>â¯0.05), which failed to differentiate these species. We identified four hybrid individuals (â¼1%) and detected bi-directional introgression between C. galapagensis and C. obscurus in the Gulf of California along the east Pacific coast of the Americas. We emphasize the importance of including a combination of mtDNA and diagnostic nuclear markers to properly assess species identification, detect patterns of hybridisation, and better inform management and conservation of these sharks, especially given the morphological similarities within the genus Carcharhinus.
Asunto(s)
Hibridación Genética , Tiburones/genética , Animales , Teorema de Bayes , California , Simulación por Computador , ADN Mitocondrial/genética , Geografía , Mitocondrias/genética , Océano Pacífico , Filogenia , Polimorfismo de Nucleótido Simple/genética , Tamaño de la MuestraRESUMEN
In adults, cirrhotic cardiomyopathy (CCM) has a significant incidence and impact on liver transplantation. For pediatric liver transplantation (pLT), data on liver-induced cardiac changes are scarce, and in particular, the comparison between cirrhotic and noncirrhotic liver disease has not been investigated. We retrospectively evaluated cardiac changes associated with CCM by echocardiography and 12-lead electrocardiogram in 198 pLT-candidates (median age 4.1 years) 4.2 before and 12 months after pLT. Results were correlated with the stage of liver fibrosis and cholestasis before transplantation. The left ventricular end-diastolic diameter (LVIDd) z score, left ventricular mass z score, and left ventricular mass index were significantly higher in cirrhotic patients (-0.10 versus 0.98, P < 0.001; -1.55 versus -0.42, P = 0.001; 78.99 versus 125.64 g/m2 , P = 0.001, respectively) compared with children with noncirrhotic liver disease. Pathological z scores (>2SDS) for the LVIDd occurred more frequently in cirrhotic patients compared with patients with noncirrhotic liver disease (31/169 versus 1/29; P = 0.03) and were significantly associated with cholestasis. All observed cardiac changes were reversible 1 year after pLT. Pathological LVIDd z scores correlated highly with intensive care unit (ICU) stay (9.6 days versus 17.1 days, respectively, P = 0.002) but not with patient survival pre-LT or post-LT. In contrast to other studies, prolonged QTc time was not associated with liver cirrhosis in our patients. In conclusion, CCM-associated cardiac changes in pLT candidates with cirrhotic liver disease are frequent, mild, and associated with cholestasis and reversible after pLT. They may impact peritransplant care and posttransplant hospitalization time. Further prospective evaluation is warranted. In particular, for QTc time prolongation etiological factors, possible protective effects of ursodeoxycholic acid treatment and the use as a screening parameter for CCM should be verified. Liver Transplantation 24 820-830 2018 AASLD.
Asunto(s)
Cardiomiopatías/epidemiología , Colestasis/complicaciones , Enfermedad Hepática en Estado Terminal/cirugía , Cirrosis Hepática/cirugía , Trasplante de Hígado , Adolescente , Cardiomiopatías/diagnóstico , Cardiomiopatías/etiología , Niño , Preescolar , Colagogos y Coleréticos/uso terapéutico , Colestasis/epidemiología , Colestasis/prevención & control , Ecocardiografía , Electrocardiografía , Enfermedad Hepática en Estado Terminal/complicaciones , Enfermedad Hepática en Estado Terminal/mortalidad , Femenino , Humanos , Incidencia , Lactante , Tiempo de Internación/estadística & datos numéricos , Cirrosis Hepática/complicaciones , Cirrosis Hepática/mortalidad , Masculino , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del Tratamiento , Ácido Ursodesoxicólico/uso terapéuticoRESUMEN
The Magpie Fiddler ray, Trygonorrhina melaleuca Scott 1954, is presently South Australia's (SA) rarest fish, represented by only three museum specimens collected near Adelaide over the past 60 years and listed as Endangered in the IUCN Red List of Threatened Species. However, there is some doubt as to whether the Magpie Fiddler Ray is a different species from the widespread and common Southern Fiddler Ray, Trygonorrhina dumerilii (Castelnau 1873), resulting in two very contrasting scenarios for marine conservation. If the Magpie Fiddler Ray is a black and white patterned variant of the Southern Fiddler Ray then it will be removed from the Red List and appear as a synonym of T. dumerilii. Conversely, if it proves to be a different species then it remains SA's rarest fish species and highly data deficient. We analysed mtDNA and the largest ever nuclear gene dataset (>4,000 loci) applied to chondrichthyan species level systematics from the most recently collected Magpie Fiddler Ray specimens and a geographically representative selection of Southern Fiddler Rays to determine the species status of this enigmatic ray. We found that the Magpie Fiddler Rays share a mitochondrial haplotype with 23 Southern Fiddler Rays and are not differentiated from 35 Southern Fiddler Rays at more than 4000 SNPs derived from DArTseq data. The morphological trait values that are putatively diagnostic for the Magpie Fiddler Ray fall within the range of variation observed among Southern Fiddler Rays. Our analyses are consistent with the notion that the Magpie Fiddler Ray is a rare colour and pattern variant of the widespread and abundant Southern Fiddler Ray. We also identified two hybrids between the Eastern and Southern Fiddler Rays, only the third time that hybrids have been identified in nature in chondrichthyans. Our results provide critical guidance in the assessment of its conservation status and an ending to a 60 year old conundrum for marine conservation.
Asunto(s)
Escarabajos/clasificación , Rajidae/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Australia , Tamaño Corporal , Escarabajos/anatomía & histología , Escarabajos/crecimiento & desarrollo , Color , Ecosistema , Femenino , Masculino , Tamaño de los Órganos , Filogenia , Rajidae/anatomía & histología , Rajidae/genética , Rajidae/crecimiento & desarrolloRESUMEN
BACKGROUND: Human cases of plague (Yersinia pestis) infection originate, ultimately, in the bacterium's wildlife host populations. The epidemiological dynamics of the wildlife reservoir therefore determine the abundance, distribution and evolution of the pathogen, which in turn shape the frequency, distribution and virulence of human cases. Earlier studies have shown clear evidence of climatic forcing on contemporary plague abundance in rodents and humans. RESULTS: We find that high-resolution palaeoclimatic indices correlate with plague prevalence and population density in a major plague host species, the great gerbil (Rhombomys opimus), over 1949-1995. Climate-driven models trained on these data predict independent data on human plague cases in early 20th-century Kazakhstan from 1904-1948, suggesting a consistent impact of climate on large-scale wildlife reservoir dynamics influencing human epidemics. Extending the models further back in time, we also find correspondence between their predictions and qualitative records of plague epidemics over the past 1500 years. CONCLUSIONS: Central Asian climate fluctuations appear to have had significant influences on regional human plague frequency in the first part of the 20th century, and probably over the past 1500 years. This first attempt at ecoepidemiological reconstruction of historical disease activity may shed some light on how long-term plague epidemiology interacts with human activity. As plague activity in Central Asia seems to have followed climate fluctuations over the past centuries, we may expect global warming to have an impact upon future plague epidemiology, probably sustaining or increasing plague activity in the region, at least in the rodent reservoirs, in the coming decades.See commentary: http://www.biomedcentral.com/1741-7007/8/108.
Asunto(s)
Clima , Reservorios de Enfermedades/microbiología , Gerbillinae/microbiología , Peste/veterinaria , Enfermedades de los Roedores/epidemiología , Enfermedades de los Roedores/historia , Enfermedades de los Roedores/microbiología , Yersinia pestis , Animales , Asia Central/epidemiología , Demografía , Historia del Siglo XX , Humanos , Modelos Biológicos , Peste/epidemiología , Peste/historia , Densidad de Población , PrevalenciaRESUMEN
BACKGROUND: Although some mechanisms of habitat adaptation of conspecific populations have been recently elucidated, the evolution of female preference has rarely been addressed as a force driving habitat adaptation in natural settings. Habitat adaptation of fire salamanders (Salamandra salamandra), as found in Middle Europe (Germany), can be framed in an explicit phylogeographic framework that allows for the evolution of habitat adaptation between distinct populations to be traced. Typically, females of S. salamandra only deposit their larvae in small permanent streams. However, some populations of the western post-glacial recolonization lineage use small temporary ponds as larval habitats. Pond larvae display several habitat-specific adaptations that are absent in stream-adapted larvae. We conducted mate preference tests with females from three distinct German populations in order to determine the influence of habitat adaptation versus neutral genetic distance on female mate choice. Two populations that we tested belong to the western post-glacial recolonization group, but are adapted to either stream or pond habitats. The third population is adapted to streams but represents the eastern recolonization lineage. RESULTS: Despite large genetic distances with FST values around 0.5, the stream-adapted females preferred males from the same habitat type regardless of genetic distance. Conversely, pond-adapted females did not prefer males from their own population when compared to stream-adapted individuals of either lineage. CONCLUSION: A comparative analysis of our data showed that habitat adaptation rather than neutral genetic distance correlates with female preference in these salamanders, and that habitat-dependent female preference of a specific pond-reproducing population may have been lost during adaptation to the novel environmental conditions of ponds.
RESUMEN
This study is based on a drug prevention project for children in the German-Polish border region known as "Pomerania." The aim of this project was to minimize risk behaviors while developing social skills as protective factors through project-specific training interventions. The present study especially investigates the development of social skills and risk behaviors at German and Polish primary schools in the critical transitional period from primary to secondary school. Data on German 4th graders and Polish 6th graders were collected by means of a longitudinal and control group design through 3rd-party assessment from teachers. The data on social skills was collected through the use of standardized assessment instruments. The study established that social skills could indeed be increased through training and that risk behaviors decreased in both of the treatment groups. The control group showed altogether an increase in risk behavior and a decrease in coping skills. In the Polish treatment group, even risk behaviors which had been detected previously decreased. The German control group showed an increase in risk behaviors and a decrease in coping skills. In the case of the younger German pupils, the effectiveness of the interventions was exhibited indirectly. Despite variations in age and cultural differences, the effects of training were noticeable in children from both countries. The intervention program offered the children adequate assistance in order to successfully cope with this stressful life event. It promoted the development of social skills while minimizing risk behaviors.
Asunto(s)
Consumo de Bebidas Alcohólicas/prevención & control , Acontecimientos que Cambian la Vida , Prevención Primaria/métodos , Asunción de Riesgos , Instituciones Académicas , Adaptación Psicológica , Niño , Femenino , Humanos , MasculinoRESUMEN
Knowing the breeding system of a species is important in order to understand individual variation in reproductive success. Large variation in reproductive success and thus reproductive skew strongly impacts on the effective number of breeders and thus the long-term effective population size (Ne). Fishes, in particular species belonging to the salmonid family, exhibit a wide diversity of breeding systems. In general, however, breeding systems are rarely studied in detail in the wild. Here we examine the breeding system of the spring-spawning European grayling Thymallus thymallus from a small Norwegian stream using parentage assignment based on the genotyping of 19 polymorphic microsatellite loci. In total 895 individual grayling fry and 154 mature grayling (57 females and 97 males) were genotyped. A total of 466 offspring were assigned a father, a mother, or a parent pair with a confidence of 90% or higher. Successfully reproducing males had on average 11.9 ± 13.3 (SD) offspring with on average 2.1 ± 1.2 partners, whereas successful females had on average 9.5 ± 12.8 offspring and 2.3 ± 1.5 partners. Parents with more partners also produced more offspring. Thus the grayling breeding system within this small stream revealed a polygynandrous breeding system, similar to what has been observed for many other salmonid fish species. The present study thus unambiguously corroborates a polygynadrous breeding system in the European grayling. This knowledge is critical for managing populations of this species, which has suffered significant local population declines throughout its range over the last several decades.
Asunto(s)
Cruzamiento , Salmonidae/genética , Animales , Femenino , Sitios Genéticos , Variación Genética , Masculino , Repeticiones de Microsatélite/genéticaRESUMEN
Divergent selection pressures induced by different environmental conditions typically lead to variation in life history, behavior, and morphology. When populations are locally adapted to their current environment, selection may limit movement into novel sites, leading to neutral and adaptive genetic divergence in allopatric populations. Subsequently, divergence can be reinforced by development of pre-or postzygotic barriers to gene flow. The threespine stickleback, Gasterosteus aculeatus, is a primarily marine fish that has invaded freshwater repeatedly in postglacial times. After invasion, the established freshwater populations typically show rapid diversification of several traits as they become reproductively isolated from their ancestral marine population. In this study, we examine the genetic and morphometric differentiation between sticklebacks living in an open system comprising a brackish water lagoon, two freshwater lakes, and connecting rivers. By applying a set of microsatellite markers, we disentangled the genetic relationship of the individuals across the diverse environments and identified two genetic populations: one associated with brackish and the other with the freshwater environments. The "brackish" sticklebacks were larger and had a different body shape than those in freshwater. However, we found evidence for upstream migration from the brackish lagoon into the freshwater environments, as fish that were genetically and morphometrically similar to the lagoon fish were found in all freshwater sampling sites. Regardless, few F1-hybrids were identified, and it therefore appears that some pre-and/or postzygotic barriers to gene flow rather than geographic distance are causing the divergence in this system.
RESUMEN
Two decades after surgery for transposition of the great arteries, the clinical status, cardiac function, cardiorespiratory performance, and neurohormonal activity of patients who underwent either atrial switch (Mustard) operations or arterial switch operations (ASOs) were compared. Sixty-two patients with simple transposition of the great arteries who underwent either Mustard (n = 34) or ASO (n = 28) procedures were included in this cross-sectional study. Following the same study protocol, clinical workup including echocardiography, stress testing, and blood work was completed for all patients. Mean ages in the 2 groups were comparable, at 20.6 ± 2.1 and 20.6 ± 3.4 years in the ASO and Mustard groups, respectively. All ASO patients were in New York Heart Association class I, whereas 59% of Mustard patients were in class II or III. Peak oxygen uptake was higher in ASO patients (percentage of predicted 80% vs 69%, p <0.01). Compared with healthy subjects, the mean Tei index for systemic ventricle was high in the 2 groups, but this parameter was significantly higher in Mustard than ASO patients (0.60 ± 0.16 vs 0.47 ± 0.14, p <0.01). The median plasma N-terminal pro-brain natriuretic peptide level in ASO patients was within the normal range, but the Mustard group had significantly higher levels (42 ng/ml [range 18 to 323] vs 172 ng/ml [range 26 to 1,018], p <0.0001). In conclusion, this cross-sectional assessment 2 decades after surgery reveals better clinical status in patients who underwent ASO compared with Mustard patients. This holds in terms of cardiac function, cardiorespiratory performance, and neurohormonal activity.
Asunto(s)
Procedimientos Quirúrgicos Cardíacos/métodos , Péptido Natriurético Encefálico/sangre , Transposición de los Grandes Vasos/cirugía , Estudios Transversales , Femenino , Estudios de Seguimiento , Alemania/epidemiología , Humanos , Masculino , Pronóstico , Estudios Retrospectivos , Tasa de Supervivencia/tendencias , Factores de Tiempo , Transposición de los Grandes Vasos/sangre , Transposición de los Grandes Vasos/mortalidad , Adulto JovenRESUMEN
Placental sequestration of Plasmodium falciparum in pregnancy may impair the usefulness of molecular markers of sulfadoxine-pyrimethamine resistance. In 300 infected, delivering women, the concordance of PCR-restriction fragment length polymorphism-derived parasite resistance alleles in matched samples from placenta and circulation was 83 to 98%. Sulfadoxine-pyrimethamine resistance typing in peripheral blood is reasonably representative of P. falciparum infecting pregnant women.