12 research outputs found

    Direct and indirect parental exposure to endocrine disruptors and elevated temperature influences gene expression across generations in a euryhaline model fish

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    Aquatic organisms inhabiting polluted waterways face numerous adverse effects, including physiological disruption by endocrine disrupting compounds (EDCs). Little is known about how the temperatures associated with global climate change may influence the response of organisms exposed to EDCs, and the effects that these combined stressors may have on molecular endpoints such as gene expression. We exposed Menidia beryllina (inland silversides) to environmentally relevant concentrations (1 ng/L) of two estrogenic EDCs (bifenthrin and 17α-ethinylestradiol; EE2) at 22 °C and 28 °C. We conducted this experiment over multiple generations to better understand the potential effects to chronically exposed populations in the wild. We exposed adult parental fish (F0) for 14 days prior to spawning of the next generation. F1 larvae were then exposed from fertilization until 21 days post hatch (dph) before being transferred to clean water tanks. F1 larvae were reared to adulthood, then spawned in clean water to test for further effects of parental exposure on offspring (F2 generation). Gene expression was quantified by performing qPCR on F0 and F1 gonads, as well as F1 and F2 larvae. We did not detect any significant differences in the expression of genes measured in the parental or F1 adult gonads. We found that the 28 °C EE2 treatment significantly decreased the expression of nearly all genes measured in the F1 larvae. This pattern was transferred to the F2 generation for expression of the follicle-stimulating hormone receptor (FSHR) gene. Expression of 17β-hydroxysteroid dehydrogenase (17β-HSD) and G protein-coupled receptor 30 (GPR30) revealed changes not measured in the previous generation. Effects of the bifenthrin treatments were not observed until the F2 generation, which were exposed to the chemicals indirectly as germ cells. Our results indicate that effects of EDCs and their interactions with abiotic factors, may not be adequately represented by singular generation testing. These findings will contribute to the determination of the risk of EDC contamination to organisms inhabiting contaminated waterways under changing temperature regimes

    New Information on the Cranial Anatomy of Acrocanthosaurus atokensis and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda)

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    Allosauroidea has a contentious taxonomic and systematic history. Within this group of theropod dinosaurs, considerable debate has surrounded the phylogenetic position of the large-bodied allosauroid Acrocanthosaurus atokensis from the Lower Cretaceous Antlers Formation of North America. Several prior analyses recover Acrocanthosaurus atokensis as sister taxon to the smaller-bodied Allosaurus fragilis known from North America and Europe, and others nest Acrocanthosaurus atokensis within Carcharodontosauridae, a large-bodied group of allosauroids that attained a cosmopolitan distribution during the Early Cretaceous.Re-evaluation of a well-preserved skull of Acrocanthosaurus atokensis (NCSM 14345) provides new information regarding the palatal complex and inner surfaces of the skull and mandible. Previously inaccessible internal views and articular surfaces of nearly every element of the skull are described. Twenty-four new morphological characters are identified as variable in Allosauroidea, combined with 153 previously published characters, and evaluated for eighteen terminal taxa. Systematic analysis of this dataset recovers a single most parsimonious topology placing Acrocanthosaurus atokensis as a member of Allosauroidea, in agreement with several recent analyses that nest the taxon well within Carcharodontosauridae.A revised diagnosis of Acrocanthosaurus atokensis finds that the species is distinguished by four primary characters, including: presence of a knob on the lateral surangular shelf; enlarged posterior surangular foramen; supraoccipital protruding as a double-boss posterior to the nuchal crest; and pneumatic recess within the medial surface of the quadrate. Furthermore, the recovered phylogeny more closely agrees with the stratigraphic record than hypotheses that place Acrocanthosaurus atokensis as more closely related to Allosaurus fragilis. Fitch optimization of body size is also more consistent with the placement of Acrocanthosaurus atokensis within a clade of larger carcharodontosaurid taxa than with smaller-bodied taxa near the base of Allosauroidea. This placement of Acrocanthosaurus atokensis supports previous hypotheses of a global carcharodontosaurid radiation during the Early Cretaceous

    Study Protocol – Diabetes and related conditions in urban Indigenous people in the Darwin, Australia region: aims, methods and participation in the DRUID Study

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    BACKGROUND: Diabetes mellitus is a serious and increasing health problem in Australia and is a designated national health priority. Diabetes and related conditions represent an even greater health burden among Indigenous Australians (Aborigines and Torres Strait Islanders), but there are critical gaps in knowledge relating to the incidence and prevalence, aetiology, and prevention of diabetes in this group, including a lack of information on the burden of disease among Indigenous people in urban areas. The DRUID Study (Diabetes and Related conditions in Urban Indigenous people in the Darwin region) was designed to address this knowledge gap. METHODS/DESIGN: The study was conducted in a specified geographic area in and around Darwin, Australia. Eligible participants underwent a health examination, including collection of blood and urine samples, clinical and anthropometric measurements, and administration of questionnaires, with an additional assessment for people with diabetes. The study was designed to incorporate local Indigenous leadership, facilitate community engagement, and provide employment and training opportunities for local Indigenous people. A variety of recruitment methods were used. A total of 1,004 eligible people gave consent and provided at least one measurement. When compared with census data for the Indigenous population living in the study area, there was a marked under-representation of males, but no substantial differences in age, place of residence, Indigenous group, or household income. Early participants were more likely than later participants to have previously diagnosed diabetes. DISCUSSION: Despite lower than anticipated recruitment, this is, to our knowledge, the largest study ever conducted on the health of Indigenous Australians living in urban areas, a group which comprises the majority of Australia's Indigenous population but about whose health and wellbeing relatively little is known. The study is well-placed to provide new information that can be used by policy makers and service providers to improve the delivery of services and programs that affect the health of Indigenous people. It also represents a valuable opportunity to establish an urban Indigenous cohort study, provided participants can be followed successfully over time
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