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Triphenyl phosphate (TPHP) is a commonly used organophosphate flame retardant and plasticizer in the United States. Using zebrafish as a model, the overall objective of this study was to identify potential organs that might be targeted by TPHP during embryonic development. Based on mRNA-sequencing, TPHP exposure from 24 to 30 h post fertilization (hpf) and 24 to 48 hpf significantly affected the abundance of 305 and 274 transcripts, respectively, relative to vehicle (0.1% DMSO) controls. In addition to minor effects on cardiotoxicity- and nephrotoxicity-related pathways, ingenuity pathway analysis (IPA) of significantly affected transcripts within 30- and 48-hpf embryos revealed that hepatotoxicity-related pathways were strongly affected following exposure to TPHP-alone. Moreover, although pretreatment with fenretinide (a retinoic acid receptor agonist) mitigated TPHP-induced pericardial edema and liver enlargement at 72 and 128 hpf, respectively, IPA revealed that fenretinide was unable to block TPHP-induced effects on cardiotoxicity-, nephrotoxicity-, and hepatotoxicity-related pathways at 48 hpf, suggesting that TPHP-induced effects on the transcriptome were not associated with toxicity later in development. In addition, based on Oil Red O staining, we found that exposure to TPHP nearly abolished neutral lipids from the embryonic head and trunk and, based on metabolomics, significantly decreased the total abundance of metabolites—including betaine, a known osmoprotectant—at 48 and 72 hpf. Overall, our data suggest that, in addition to the heart, TPHP exposure during early development results in adverse effects on the liver, lipid utilization, and osmoregulation within embryonic zebrafish. [ABSTRACT FROM AUTHOR]

Resistance to fludioxonil in Botrytis cinerea and B. fragariae was previously found to be linked to either overexpression of the drug efflux pump atrB activated by mutations in transcription factor mrr1 or to mutations in the osmoregulation gene os1. In the present study, isolates of B. cinerea, Botrytis group S, or B. fragariae collected from strawberry fields in the United States were resistant to fludioxonil with half-maximal effective concentration values ranging from 0.04 to 0.43 µg/ml for B. cinerea, 0.03 to 1.03 µg/ml for Botrytis group S, and 0.28 to 3.48 µg/ml for B. fragariae. Analyses of mrr1 sequences revealed various mutations linked to fludioxonil resistance in B. cinerea and Botrytis group S isolates. However, no mutations in mrr1 correlated with atrB overexpression-mediated resistance in B. fragariae isolates. Neither nucleotide variations in the 1,370-bp upstream region of atrB nor increased atrB copy numbers could explain the atrB overexpression in these B. fragariae isolates. Mutations in os1 conferred resistance to iprodione in B. cinerea and Botrytis group S isolates; none correlated with resistance to fludioxonil in B. fragariae. In contrast to European isolates, U.S. B. fragariae isolates contained a 3-bp insertion in the coding region of os1. These isolates were more sensitive to osmotic stress but it is unclear whether the insertion is responsible for this phenotype. Our findings suggest that atrB overexpression-associated fludioxonil resistance is an across-species mechanism of resistance to fludioxonil that can be induced by mutations in mrr1 and other, still-unknown mechanisms. [ABSTRACT FROM AUTHOR]

part of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE), sediment samples were collected from 447 randomly selected littoral sites along the main channels of the Ohio, Missouri, and Upper Mississippi Rivers between 2004 and 2006. Toxicity of these sediment samples was measured using a 7-day Hyalella azteca survival and growth test. Sixty-five sites (14.5%) exhibited lethal toxicity, and 130 sites (29.1%) exhibited decreased growth. In the EMAP-GRE probabilistic sampling design, each sampled site had a weight associated with it that determined the length (and proportion) of the river represented by that sample point in the population. Weighted whole-river estimates indicated that of the 4721 river km sampled, sediment from 15.9 ± 3.0% of the river (752 ± 50 km) were lethally toxic, 27.4 ± 3.5% (1289 ± 57 km) were toxic by way of growth inhibition, and 40.0 ± 3.7% (1887 ± 68 km) exhibited either lethal or growth toxicity. Selected toxic samples were analyzed for 21 pesticides, 20 polychlorinated biphenyl congeners, and 6 polybrominated diphenyl ether congeners. For all of the samples tested, the concentration levels of these analytes were mostly lower than known toxicity thresholds, and neither unionized ammonia concentration nor osmotic stress (as measured by conductivity) could account for the toxicity found in sediments. The spatial pattern of sediment toxicity cannot be readily explained by urbanization or agricultural land use at the subcatchment scale. We speculate that the distribution of toxic sediment is more likely due to a combination of localized sources, including polluted tributaries, and the redistribution of contaminated sediments from upriver. The sediment toxicity results from this study will be used, in combination with other sediment, biologic, and habitat metrics and indicators collected in the EMAP-GRE study, to help interpret and assess the condition of the Ohio, Upper Mississippi, and Missouri Rivers. [ABSTRACT FROM AUTHOR]

Field observations were supplemented with laboratory experiments to reveal patterns of salinity selection and preference for grey snapper Lutjanus griseus ( c. 21 cm total length, LT), an ecologically and economically important species in the south-eastern U.S.A. Fish abundance data were examined from a long-term field survey conducted in the mangrove habitats of Biscayne Bay, Florida, where salinities ranged from <1 to 40. First, regression analyses indicated significant, positive linear relationships with salinity for both L. griseus frequency of occurrence and concentration (density when present). These patterns are inconsistent with physiological expectations of minimizing energetic osmoregulatory costs. Next, the salinity preference and swimming activity of 11 L. griseus (ranging from 18 to 23 cm LT) were investigated using a newly developed electronic shuttlebox system. In the laboratory, fish preferred intermediate salinities in the range of 9–23. Swimming activity (measured in terms of spontaneous swimming speed) followed a parabolic relationship with salinity, with reduced activity at salinity extremes perhaps reflecting compensation for higher osmoregulatory costs. It is suspected that the basis of the discrepancy between laboratory and field observations for size classes at or near maturity ultimately relates to the reproductive imperative to move towards offshore (high-salinity) coral-reef habitats, a necessity that probably overrides the strategy of minimizing osmoregulatory energetic costs. [ABSTRACT FROM AUTHOR]

Aquaporins form water channels that play major roles in a variety of physiological processes so that altered expression or function may underlie pathological conditions. In order to identify compounds that modulate aquaporin function, we have implemented a functional assay based on rapid measurement of osmotically induced cell volume changes to screen several libraries of diverse drugs. The time course of fluorescence changes in calcein-loaded cells was analyzed during an osmotic challenge using a 96-multiwell fluorescence plate reader. This system was validated using astrocyte primaiy cultures and flbroblasts that strongly express endogenous AQP4 and AQP1 proteins, respectively, as well as AQP4-transfected cells. We screened 3575 compounds, including 418 FDA-approved and commercially available drugs, for their effect on AQP-mediated water transport Primary screening yielded 10 compounds that affected water transport activity in both astrocytes and AQP4- transfected cells and 42 compounds that altered cell volume regulation in astrocytes. Selected drugs were then analyzed on AQP1-expressing ellythmcytes and AQP4-expressing membrane vesicles by stopped-flow light scattering Four molecules of the National Cancer Institute's chemical library (NSC164914, NSC670229, N5C168597, NSC301460) were identified that differentially affected both AQP4 and AQP1 mediated water transport, with EC50 values between 20 and 50 μM. This fluorescence microplate reader. based assay may, thus, provide a platform for high- throughput screening which, when coupled to a secondary evaluation to confirm target specificity, should allow discovery of AQP-specific compounds for novel therapeutic strategies in the treatment of water balance disorders. [ABSTRACT FROM AUTHOR]

The article discusses findings of a study which evaluated changes in oxygen consumption rate, hemolymph osmolarity, and glutathione S-transferase activity following exposure of adult Uca pugnax to salt marsh sediment spiked with different permethrin concentrations for 96 hours. Among the pyrethroids developed, permethrin receives wide use in agricultural, urban and salt marsh mosquito control. For instance, in the U.S., annual permethrin use averages 2 million pounds with 70 percent used for nonagricultural purposes.

Possible links between cold-tolerance and desiccation resistance were examined between larvae of the goldenrod gall fly collected from Michigan, southern Ohio, and Alabama locations as their host plant senesced. After acclimation to 5°C, Michigan-collected larvae were more cold-tolerant (25% survival after a 96 h exposure to −40°C) than larvae from Ohio (10% survival) and Alabama (0% survival). Increased cold-tolerance was partially linked to higher concentrations of the cryoprotectant glycerol (Michigan: 500 ± 30 mmol; Ohio: 270 ± 20; Alabama: 220 ± 20). Moreover, cryoprotectants may have functioned to reduce rates of overall and cuticular water loss for Michigan larvae, 0.10 ± 0.01 and 0.037 ± 0.003 μg mm−2 h−1, respectively, values that were 40-44% lower than those for Ohio and Alabama larvae and may represent a link between desiccation resistance and cold-tolerance. After acclimation to 20°C, Alabama-collected larvae had metabolic rates that were 40% lower than those from Ohio and Michigan that averaged 0.100 ± 0.006 μl of CO2 produced g−1 h−1. The lower metabolic rate of Alabama-collected larvae at 20°C likely resulted in reduced respiratory transpiration that may represent a mechanism to maintain water balance at the higher overwintering temperatures they typically experience. [ABSTRACT FROM AUTHOR]

Examines the continuing debate over salt intake and its effect on human health. New recommendations for a reduced salt intake from the Institute of Medicine of the National Academies in the United States; Amount of salt needed for survival; Results from a recent Canadian research group which made a different recommendation; How the issue could cause entire industries to change the way they do business; Most sodium content which is found in processed foods; Canadians who charge the American study was not representative of the population; Effects of low sodium on the human body.

The southern flounder, Paralichthys lethostigma, is an important commercial and recreational marine flatfish that inhabits estuaries and shelf waters in the south Atlantic, from North Carolina through the Gulf coasts, with the exception of south Florida. Because juvenile and adult fish are highly euryhaline, it is a prime candidate for aquaculture. Methods for captive spawning of southern flounder are well developed; however, information on optimal culture requirements of the early larval stages is required for reliable mass production of juveniles.To determine the optimal photoperiod and salinity conditions for culture from hatching to day 15 post-hatching (d15ph), embryos were stocked into black 15-l tanks (75 l−1) under four photoperiods (24L:0D, 18L:6D, 12L:12D, and 6L:18D) and two salinities (25 and 34 ppt) in a 4×2 factorial design. Temperature was 18 °C, light intensity was 150 lx, and aeration was 50 ml min−1. Significant (P<0.05) effects of photoperiod and salinity on growth (notochord length, wet and dry weights) were obtained. Growth increased with increasing photoperiod and salinity and was significantly greater at 24L and 18L than at 12L or 6L, and at 34 than at 25 ppt. On d11ph and d15ph, significant interactive effects between photoperiod and salinity on growth (wet and dry weights) were also evident. Growth of larvae reared at 25 ppt increased with increasing photoperiod to a maximum at 24L, while growth of larvae at 34 ppt reached a plateau at 18L. While there were no significant photoperiod effects on these parameters, larval survival, body water percentage, and larval osmolality on d15ph were significantly higher at 34 than at 25 ppt (41% vs. 16% survival; 322 vs. 288 mosM kg−1; and 84% vs. 76% water, respectively), suggesting stress and nonadaptation to 25 ppt, a salinity more nearly isoosmotic than full-strength seawater. Since larvae from both salinity treatments were neutrally or positively buoyant at 34 ppt, but negatively buoyant at 25 ppt, larvae reared at 25 ppt probably allocated energy to maintain vertical positioning, compromising growth and survival.The results demonstrate that growth and survival of early-stage southern flounder larvae are maximized under long photoperiods of 18–24L and in full-strength seawater. Longer photoperiods probably extend the time larvae have for feeding, while full-strength seawater salinity optimizes buoyancy and vertical positioning, conserving energy. The results show that early larval stage southern flounder larvae are not entirely euryhaline, which involves not only the ability to osmoregulate, but to conserve energy under reduced buoyancy. This is consistent with suboptimal vs. maximal growth of larvae reared at 25 and 34 ppt, respectively, under 18L (i.e., photoperiod×salinity interaction). This is also consistent with other reports that tolerance to lower salinities in these euryhaline flatfish increases post-metamorphosis when transition from a pelagic to benthic existence alleviates the need to counteract reduced buoyancy. [Copyright &y& Elsevier]

Birds that breed in hot, arid environments experience unique physiological demands resulting from efforts to maintain positive water balance when ambient temperatures are high, but humidity and water availability are low. We provided water to Black-throated Sparrows (Amphispiza bilineata) on breeding territories in the Mojave Desert of southern California to examine the effects of water availability on reproduction in desert birds, independent of the increase in food availability commonly associated with increased precipitation in arid ecosystems. In both years of the study (2000 and 2001), water-supplemented (treatment) pairs laid significantly larger clutches than did control pairs. In 2000, the drier of the two years, the mean clutch size of treatment pairs was almost 0.5 egg larger, or about 16% larger, than control pairs. Overall, the mean egg volume per nest in treatment and control pairs was not significantly different,, and the mean proportion of eggs hatched was not significantly different at α = 0.05, but was nearly so. Daily nest survival probabilities were not greater in treatment nests than in control nests in 2000 or in 2001. Treatment nests did not produce a greater mean number of young surviving to day 8 than did control nests, although the trend is of greater means in treatment nests. The results of our study indicate that for species like the Black-throated Sparrow that are abundant in deserts, are successful in breeding there, and can survive without drinking water, water availability in arid environments can nevertheless impose limitations on reproduction. [ABSTRACT FROM AUTHOR]

ABSTRACTWe investigated the contribution of internal water storage and efficiency of water transport to the maintenance of water balance in six evergreen tree species in a Hawaiian dry forest. Wood-saturated water content, a surrogate for relative water storage capacity, ranged from 70 to 105%, and was inversely related to its morphological correlate, wood density, which ranged between 0·51 and 0·65 g cm-3. Leaf-specific conductivity (kL) measured in stem segments from terminal branches ranged from 3 to 18 mmol m-1 s-1 MPa-1, and whole-plant hydraulic efficiency calculated as stomatal conductance (g) divided by the difference between predawn and midday leaf water potential (ΨL), ranged from 70 to 150 mmol m-2 s-1 MPa-1. Hydraulic efficiency was positively correlated with kL (r2 = 0·86). Minimum annual ΨL ranged from - 1·5 to - 4·1 MPa among the six species. Seasonal and diurnal variation in ΨL were associated with differences among species in wood-saturated water content, wood density and kL. The species with higher wood-saturated water content were more efficient in terms of long-distance water transport, exhibited smaller diurnal variation in ΨL and higher maximum photosynthetic rates. Smaller diurnal variation in ΨL in species with higher wood-saturated water content, kL and hydraulic efficiency was not associated with stomatal restriction of transpiration when soil water deficit was moderate, but avoidance of low minimum seasonal ΨL in these species was associated with a substantial seasonal decline in g. Low seasonal minimum ΨL in species with low kL, hydraulic efficiency, and wood-saturated water content was associated with higher leaf solute content and corresponding lower leaf turgor loss point. Despite the species-specific differences in leaf water relations characteristics, all six evergreen tree species shared a common functional relationship defined primarily by kL and stem water storage capacity. [ABSTRACT FROM AUTHOR]

Midday water potentials of blades of the dune grasses Ammophila arenaria (L.) Link and Elymus mollis Trin. ex Spreng. growing in situ declined over the summer growing period, indicating a trend of increasing water stress. An analysis of the water relations characteristics of these blades using pressure-volume techniques demonstrated that both species increased bulk osmotic pressure at full hydration (̅πo) and, therefore, bulk turgor as an acclimation response. In A. arenaria, however, the increase of osmotic pressure (+0.35 MPa) was entirely the result of decreasing symplasmic water content. The increase of osmotic pressure (+0.54 MPa) observed in E. mollis blades was due to solute accumulation (72% of Δ ̅π o) and to a lesser degree, decreased symplasmic water content (28% of Δ ̅πo). Osmotic adjustment in E. mollis blades was accompanied by a significant decrease in tissue elasticity (̅ εmax went from 12 to 19 MPa). The elastic properties of A. arenaria blades remained constant over the same period and had a maximum modulus (10 MPa) that was always less than that of E. mollis. As estimated from Höfler plots, these seasonal adjustments of osmotic pressure and differences in tissue elasticity enabled plants in situ to maintain turgor pressure in the range of 0.5-0.6 MPa at the lowest water potentials of mid-August. Laboratory-grown plants exhibited the species-specific differences in osmotic pressure, turgor pressure, and tissue elasticity observed in field plants. Although certain alterations of leaf structure were expected to coincide with the observed changes and species-specific differences in symplasmic water content and tissue elasticity, these could not be detected by measurements of specific leaf weight or the ratio of dry matter to saturated water content. [ABSTRACT FROM AUTHOR]

We quantified drinking behavior in three species of North American watersnakes: Nerodia clarkii , which is a marine or brackish water amphibious species, and Nerodia fasciata and Nerodia taxispilota , both freshwater amphibious species. All three species have relatively small and similar thresholds of dehydration (TH, approximately -4% loss of body mass) that elicit thirst and drinking of fresh water. These species have higher thirst sensitivity than several species of hydrophiine and laticaudine sea snakes, which are characterized by much lower TH (greater dehydration, -9% to <-20%). Nerodia clarkii , which is often found in coastal oceanic water, refused to drink seawater, but drank fresh water when dehydrated. In separate trials involving dehydration of N. clarkii and N. fasciata that were concurrently fed fish at regular intervals, snakes eventually refused to eat at TH of approximately -12% of original body mass, but resumed eating after they were allowed to drink fresh water and rehydrate. The drinking behaviors of Nerodia corroborate previous data on the importance of fresh water for drinking, and they complement growing evidence that dietary water does not itself mitigate dehydration in snakes. These new data increase understanding of water relationships in the context of evolutionary transitions from land to sea, and they emphasize the importance of fresh water resources in the conservation of coastal and marine species of reptiles., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)

Salinity variability can act as a disturbance to communities in estuarine systems. Climate models predict changes in precipitation patterns will increase future hydrological variability, particularly in the southwestern United States. This study used infaunal community characterization, stomach content, and stable isotope analyses to evaluate the functioning of an estuarine food web over a range of wet and dry conditions. Baffin Bay is a predominantly hypersaline system in the semi-arid region of South Texas, USA supporting large populations of Pogonias cromis , black drum, a commercially important benthic predator. Salinity was the best predictor of changes in benthic macrofauna biomass, abundance, and diversity in Baffin Bay. Isotopic analyses of muscle tissues indicate that black drum use resources, particularly deposit-feeding benthic macrofauna, from both Baffin Bay and an adjacent system under normal estuarine salinity (≤35) conditions, but are more constrained to Baffin Bay under hypersaline (>35) conditions. This spatial restriction may be due to the energetic cost of osmotic regulation in hypersaline conditions, which can limit movement of euryhaline fish. Understanding the impacts of salinity change on benthic prey availability and trophic interaction dynamics is critical to determining ecosystem-scale effects of salinity variability. Image 1 • High salinity leads to low benthic prey availability in the Baffin Bay complex. • Deposit feeders compose the majority of Baffin Bay complex benthic predator diet. • Lower salinity conditions favor fish migration for feeding purposes. [ABSTRACT FROM AUTHOR]

The author reflects on several medical cases in the U.S. which a person died due to excessive drinking of water. He cites an example of a woman who drink 6 liters within 3 hours, without going to bathroom, during a competition. He suggested that the water intake of a person should be regulated because it could affect the extracellular osmolality of the person.

Field studies were conducted to determine levels of gill aluminium as an index of acidification effects on migrating Atlantic salmon Salmo salar smolts in the north-eastern U.S.A. along mainstem river migration corridors in several major river basins. Smolts emigrating from the Connecticut River, where most (but not all) tributaries were well buffered, had low or undetectable levels of gill aluminium and high gill Na(+) /K(+) -ATPase (NKA) activity. In contrast, smolts emigrating from the upper Merrimack River basin where most tributaries are characterized by low pH and high inorganic aluminium had consistently elevated gill aluminium and lower gill NKA activity, which may explain the low adult return rates of S. salar stocked into the upper Merrimack catchment. In the Sheepscot, Narraguagus and Penobscot Rivers in Maine, river and year-specific effects on gill aluminium were detected that appeared to be driven by underlying geology and high spring discharge. The results indicate that episodic acidification is affecting S. salar smolts in poorly buffered streams in New England and may help explain variation in S. salar survival and abundance among rivers and among years, with implications for the conservation and recovery of S. salar in the north-eastern U.S.A. These results suggest that the physiological condition of outmigrating smolts may serve as a large-scale sentinel of landscape-level recovery of atmospheric pollution in this and other parts of the North Atlantic region., (© 2015 The Fisheries Society of the British Isles.)

Energy Recovery Inc of San Leandro, California, USA – a company which designs and develops energy-recovery systems that help to make desalination more affordable – has announced that its PX Pressure Exchanger devices are being used in the world''s first ‘osmotic power plant’. [Copyright &y& Elsevier]