Researching the Ends of Identity: Birth and Death on Social Media

This paper argues that expanding the scope of social media studies to examine birth and early life at one end, and death and memorialisation at the other, demonstrates that social media is never just about an individual, but also the way individuals are always already joined together as families, groups, communities and more. Mapping these ends of identity also reveals more of the nuances of everyday social media use and its impact

Acute Toxicity, Teratogenic, and Estrogenic Effects of Bisphenol A and Its Alternative Replacements Bisphenol S, Bisphenol F, and Bisphenol AF in Zebrafish Embryo-Larvae

This is the author accepted manuscript. The final version is available from American Chemical Society via the DOI in this recordBisphenol A (BPA), a chemical incorporated into plastics and resins, has estrogenic activity and is associated with adverse health effects in humans and wildlife. Similarly structured BPA analogues are widely used but far less is known about their potential toxicity or estrogenic activity in vivo. We undertook the first comprehensive analysis on the toxicity and teratogenic effects of the bisphenols BPA, BPS, BPF, and BPAF in zebrafish embryo-larvae and an assessment on their estrogenic mechanisms in an estrogen-responsive transgenic fish Tg(ERE:Gal4ff)(UAS:GFP). The rank order for toxicity was BPAF > BPA > BPF > BPS. Developmental deformities for larval exposures included cardiac edema, spinal malformation, and craniofacial deformities and there were distinct differences in the effects and potencies between the different bisphenol chemicals. These effects, however, occurred only at concentrations between 1.0 and 200 mg/L which exceed those in most environments. All bisphenol compounds induced estrogenic responses in Tg(ERE:Gal4ff)(UAS:GFP) zebrafish that were inhibited by coexposure with ICI 182 780, demonstrating an estrogen receptor dependent mechanism. Target tissues included the heart, liver, somite muscle, fins, and corpuscles of Stannius. The rank order for estrogenicity was BPAF > BPA = BPF > BPS. Bioconcentration factors were 4.5, 17.8, 5.3, and 0.067 for exposure concentrations of 1.0, 1.0, 0.10, and 50 mg/L for BPA, BPF, BPAF, and BPS, respectively. We thus show that these BPA alternatives induce similar toxic and estrogenic effects to BPA and that BPAF is more potent than BPA, further highlighting health concerns regarding the use of BPA alternatives.Natural Environment Research Council (NERC

Estrogenic mechanisms and cardiac responses following early life exposure to Bisphenol A (BPA) and Its metabolite 4-Methyl-2,4-bis(p -hydroxyphenyl)pent-1-ene (MBP) in zebrafish

This is the author accepted manuscriptEnvironmental exposure to Bisphenol A (BPA) has been associated with a range of adverse health effects, including on the cardiovascular system in humans. Lack of agreement on its mechanism(s) of action likely stem from comparisons between in vivo and in vitro test systems and potential multiple effects pathways. In rodents, in vivo, metabolic activation of BPA produces 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), which is reported to be up to 1000 times more potent as an estrogen than BPA. We investigated the estrogenic effects and estrogen receptor signaling pathway(s) of BPA and MBP following early life exposure using a transgenic, estrogen responsive (ERE-TG) zebrafish and a targeted morpholino approach to knockdown the three fish estrogen receptor (ER) subtypes. The functional consequences of BPA exposure on the cardiovascular system of zebrafish larvae were also examined. The heart atrioventricular valves and the bulbus arteriosus were primary target tissues for both BPA and MBP in the ERE-TG zebrafish, and MBP was approximately 1000-fold more potent than BPA as an estrogen in these tissues. Estrogen receptor knockdown with morpholinos indicated that the estrogenic responses in the heart for both BPA and MBP were mediated via an estrogen receptor 1 (esr1) dependent pathway. At the highest BPA concentration tested (2500 μg/L), alterations in the atrial:ventricular beat ratio indicated a functional impact on the heart of 5 days post fertilization (dpf) larvae, and there was also a significantly reduced heart rate in these larvae at 14 dpf. Our findings indicate that some of the reported adverse effects on heart function associated with BPA exposure (in mammals) may act through an estrogenic mechanism, but that fish are unlikely to be susceptible to adverse effects on heart development for environmentally relevant exposures.Natural Environment Research Council (NERC)Biotechnology & Biological Sciences Research Council (BBSRC)Biotechnology & Biological Sciences Research Council (BBSRC

Cardiovascular Effects and Molecular Mechanisms of Bisphenol A and Its Metabolite MBP in Zebrafish

 This is the author accepted manuscript. The final version is available on open access from American Chemical Society via the DOI in this record The plastic monomer bisphenol A (BPA) is one of the highest production volume chemicals in the world and is frequently detected in wildlife and humans, particularly children. BPA has been associated with numerous adverse health outcomes relating to its estrogenic and other hormonal properties, but direct causal links are unclear in humans and animal models. Here we simulated measured (1×) and predicted worst-case (10×) maximum foetal exposures for BPA, or equivalent concentrations of its metabolite MBP, using fluorescent reporter embryo-larval zebrafish capable of quantifying Estrogen Response Element (ERE) activation throughout the body. Heart valves were primary sites for ERE activation by BPA and MBP, and transcriptomic analysis of micro-dissected heart tissues showed that both chemicals perturbed similar downstream molecular pathways and biological processes, including down-regulation of cartilage morphogenesis and filamentous protein synthesis. Collagen/keratin deficiency and impact on heart valve structural integrity were confirmed by histopathology for high-level MBP exposure, and structural defects (abnormal curvature) of the atrio-ventricular valves corresponded with impaired cardiovascular function (reduced ventricular beat rate and blood flow). Our results are the first to demonstrate plausible mechanistic links between ERE activation in the heart valves by BPA’s reactive metabolite MBP and the development of valvular- cardiovascular disease states.Biotechnology & Biological Sciences Research Council (BBSRC)Natural Environment Research Council (NERC

Effect of Monensin, Estradiol Controlled Release Implants and Supplement on Performance in Grazing Steers

Five trials in five locations in the United States involving 512 steers were conducted to evaluate the effect of monensin [200 mg/d in .9 kg of supplement (Rumensin)] and estradiol- controlled release implants (Compudose) administered alone and in combination on average daily gain (ADG) in steers on pasture. The effect of energy supplementation on rate of gain was also evaluated in these same trials. The initial weight of steers averaged 250 kg and the average duration of the five trials was 124 d. Estradiol-controlled release implants increased ADG by 15.6% (.095 kg/d; P\u3c.0001) and monensin increased ADG by 8.1% (.054 kg/d; P\u3c.05). The combination of estradiol-controlled release implant and monensin increased ADG by 27.4% (.I68 kg/d). Treatment responses were additive relative to ADG response, with no interaction observed between the treatments. Nine-tenths kilogram of an energy supplement/d increased ADG by 12.4% (.073 kg/d; P\u3c.Ol)