Effect of naturally occurring bromophenols on sulfate reduction and ammonia oxidation in intertidal sediments

We examined the effect on ammonium oxidation and sulfate reduction of several brominated compounds [4-bromophenol, 2,4-dibromophenol (2,4-DBP), 2,6-dibromophenol and 2,4,6-tribromophenol] that occur naturally in enteropneusts. We compared rates of these processes with and without bromoorganics using bulk intertidal sediments and burrow wall sediments from 3 enteropneust species (2 containing 2,4-DBP and 1 containing 2,3,4-tribromopyrrole), a mollusc (Mya arenaria) and a polychaete (Nereis virens). Sulfate reduction in bulk sediment was unaffected by bromophenols at concentrations sediment, but was inhibited temporarily at 1 μmol cm-3. Sulfate reduction in burrow wall sediments differed from bulk sediments, but was not correlated with concentrations of naturally occurring bromophenols. Ammonium oxidation was inhibited in surface sediments by bromophenol concentrations as low as 1 nmol cm-3 sediment. Ammonium oxidation was enhanced in burrow wall sediments of N. virens, M. arenaria and the enteropneust Saccoglossus bromophenolosus relative to surface sediments, but was markedly lower and negatively correlated with ambient 2,4-DBP in burrow wall sediments of a second enteropneust, Protoglossus graveolens

Predator deterrence and 2,4-dibromophenol conservation by the enteropneusts Saccoglossus bromophenolosus and Protoglossus graveolens

Saccoglossus bromophenolosus King et al., 1994 and Protoglossus graveolens Giray and King, 1996 contain high concentrations of 2,4-dibromophenol (DBP), the function of which is uncertain. Mature enteropneusts that were collected from the field and maintained in vitro without bromide retained DBP, which is inconsistent with active DBP secretion into the burrow environment. DBP was also conserved during field manipulations that decreased food availability in situ. Further, DBP did not deter predation in feeding experiments with the anomuran crab Pagurus longicarpus and the polychaetes Glycera dibranchiata, Nereis virens and Nepthys incisa. The hermit crabs fed on S. bromophenolosus readily, and in preference to shrimp, in the field and in laboratory aquaria. Elevated DBP levels were measured in crabs that had recently consumed S. bromophenolosus, and ingested DBP was degraded to 4-bromophenol. Elevated levels of DBP in polychaetes were associated with the disappearance of enteropneusts during in vitro feeding experiments. Control incubations with DBP-containing agar plugs indicated that the polychaetes did not accumulate DBP passively. These results suggest that DBP is not an effective anti-predatory agent against hermit crabs or some predatory polychaetes. A definitive role for DBP in enteropneusts remains to be shown

Intergenerational food-focused media literacy in Jamaica

Media use has been linked to unhealthy eating, but there is evidence that parent discussion about media and media literacy can inoculate against negative media effects. Therefore, we examined the relationships between mothers’ food-focused media literacy and their discussions about media and their adolescents’ food-focused media literacy in a survey of 82 mother-adolescent dyads in Jamaica, a middle-income country where obesity is rising. As expected, mothers’ food-focused media literacy was both greater than and positively related to their adolescents’ food-focused media literacy. The nature of the discussion (i.e., emotional intensity) about the time adolescents spent using media (TV, computer/electronics) positively related to adolescents’ media literacy. This study contributes to understanding how mothers may shape their adolescent’s media literacy and underscores the importance of considering parent-adolescent discussions for food-focused media literacy

The impact of geopolitical risk on CO2 emissions inequality: Evidence from 38 developed and developing economies

This paper analyses the impact of geopolitical risk on carbon dioxide (CO 2) emissions inequality in the panel dataset of 38 developed and developing economies from 1990 to 2019. At this juncture, the empirical models control for the effects of globalisation, capital-labour ratio, and per capita income on CO 2 emissions inequality. The panel cointegration tests show a significant long-run relationship among the related variables in the empirical models. The panel data regression estimations indicate that geopolitical risk, capital-labour ratio, and per capita income increase CO 2 emissions inequality. However, globalisation negatively affects CO 2 emissions inequality in the panel dataset of 38 developed and developing countries. The pairwise panel heterogeneous causality test results align with these benchmark results and indicate no reverse causality issue. Potential policy implications are also discussed.</p

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates' testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicular cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30. nM sodium selenite (SS), and 10 μM selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status. © 2010 Elsevier Inc

Artifact-Removed Quantitative Analysis of Choriocapillaris Flow Voids

Objectives:To investigate choriocapillaris flow voids (FV) with a new optical coherence tomography angiography (OCTA) image processing strategy that can eliminate artifacts caused by vitreous opacities, sub-retinal pigment epithelium fluid and deposits, and subretinal fluid (SRF) by thresholding the en-face OCT image of the outer retina.Materials and Methods:We retrospectively reviewed medical records of patients with drusen and patients with active central serous chorioretinopathy (CSC). FV number (FVn), average area (FVav), and maximum area (FVmax) and the percentage of nonperfused choriocapillaris area (PNPCA) obtained using the proposed strategy were compared with those obtained by removing only artifacts caused by the superficial capillary plexus (SCP).Results:The SRF group included 21 eyes with active CSC and the drusen group included 29 eyes with nonexudative age-related macular degeneration. FVav, FVmax, FVn, and PNPCA obtained using the algorithm were significantly lower than those obtained by removing only SCP-related artefacts in both groups (all p<0.05). The algorithm was also able to remove 96.9% of artifacts secondary to vitreous opacities and all artifacts secondary to serous pigment epithelial detachments.Conclusion:Choriocapillaris nonperfusion areas on OCTA images may be overestimated in eyes with RPE abnormalities and SRF due to artifacts. These artifact areas on choriocapillaris OCTA images can be removed using thresholded images of the outer retina en-face OCT scans. Our new artifact-removal strategy is useful in the assessment of choriocapillaris FV in eyes with SRF, drusen, drusen-like deposits, and pigment epithelial detachment

Fast Visuomotor Processing of Redundant Targets: The Role of the Right Temporo-Parietal Junction

Parallel processing of multiple sensory stimuli is critical for efficient, successful interaction with the environment. An experimental approach to studying parallel processing in sensorimotor integration is to examine reaction times to multiple copies of the same stimulus. Reaction times to bilateral copies of light flashes are faster than to single, unilateral light flashes. These faster responses may be due to ‘statistical facilitation’ between independent processing streams engaged by the two copies of the light flash. On some trials, however, reaction times are faster than predicted by statistical facilitation. This indicates that a neural ‘coactivation’ of the two processing streams must have occurred. Here we use fMRI to investigate the neural locus of this coactivation. Subjects responded manually to the detection of unilateral light flashes presented to the left or right visual hemifield, and to the detection of bilateral light flashes. We compared the bilateral trials where subjects' reaction times exceeded the limit predicted by statistical facilitation to bilateral trials that did not exceed the limit. Activity in the right temporo-parietal junction was higher in those bilateral trials that showed coactivation than in those that did not. These results suggest the neural coactivation observed in visuomotor integration occurs at a cognitive rather than sensory or motor stage of processing

The relationships between exogenous and endogenous antioxidants with the lipid profile and oxidative damage in hemodialysis patients

Background: We sought to investigate the relationships among the plasma levels of carotenoids, tocopherols, endogenous antioxidants, oxidative damage and lipid profiles and their possible effects on the cardiovascular risk associated with hemodialysis (HD) patients. Methods: The study groups were divided into HD and healthy subjects. Plasma carotenoid, tocopherol and malondialdehyde (MDA) levels, as well as erythrocyte reduced glutathione (GSH), were measured by HPLC. Blood antioxidant enzymes, kidney function biomarkers and the lipid profiles were analyzed by spectrophotometric methods. Results: Plasma lycopene levels and blood glutathione peroxidase (GPx) activity were significantly decreased in HD patients compared with healthy subjects. Total cholesterol, low-density lipoprotein cholesterol (LDL-c), creatinine, urea, MDA, GSH, superoxide dismutase (SOD) and catalase (CAT) were significantly increased in HD (p < 0.05). Lycopene levels were correlated with MDA (r = -0.50; p < 0.01), LDL-c (r = -0.38; p = 0.01) levels, the LDL-c/HDL-c index (r = -0.33; p = 0.03) and GPx activity (r = 0.30; p = 0.03). Regression models showed that lycopene levels were correlated with LDL-c (β estimated = -31.59; p = 0.04), while gender was correlated with the TC/HDL-c index and triglycerides. Age did not present a correlation with the parameters evaluated. GPx activity was negatively correlated with MDA levels and with the LDL-c/HDL-c and CT/HDL-c indexes. Conclusions: Lycopene may represent an additional factor that contributes to reduced lipid peroxidation and atherogenesis in hemodialysis patients