Identification of an Obese Eating Style in 4‐year‐old Children Born at High and Low Risk for Obesity

This study tested whether children's eating behavior and parental feeding prompts during a laboratory test meal differ among children born at high risk (HR) or low risk (LR) for obesity and are associated with excess child weight gain. At 4 years of age, 32 HR children (mean maternal prepregnancy BMI = 30.4 kg/m²) and 29 LR children (maternal BMI = 19.6 kg/m²) consumed a test meal in which their eating behavior was assessed, including rate of caloric consumption, mouthfuls/min, and requests for food. Parental prompts for the child to eat also were measured at year 4, and child body composition was measured at ages 4 and 6 years. T‐tests, and logistic and multiple regression analyses tested study aims. Results indicated that HR and LR children did not differ in eating rate or parental feeding prompts. Greater maternal BMI, child mouthfuls of food/min, and total caloric intake/min during the test meal predicted an increased risk of being overweight or obese at age 6, whereas greater active mealtime was associated with a reduced risk of being overweight or obese. Regression analyses indicated that only mouthfuls of food/min predicted changes in BMI from 4 to 6 years, and mouthfuls of food/min and gender predicted 2‐year changes in sum of skinfolds and total body fat. Thus, a rapid eating style, characterized by increased mouthfuls of food/min, may be a behavioral marker for the development of childhood obesity.     

Ion-mediated water flow

Summary The electroosmotic flows of solution produced by the chloride salts of H, Na, K, tetramethylammonium (TMA) and tetraethylammonium (TEA) through three membranes of net negative charge and high water content (40 to 60%) have been obtained. The amount of solution transported, (EO _s), increased in the order: HCl, KCl, NaCl, TMACl and TEACl in a membrane of 43% hydration. In membranes 60% hydrated the order became HCl, KCl, NaCl, TEACl and TMACl. (EO _s) for a salt increased as membrane hydration became larger. The permselectivity of the three membranes for cations declined in the order: HCl, KCl=NaCl, TMACl and TEACl. Cation permselectivity also declined with increases in membrane hydration. The (EO _s) is a net solution flow and is the difference between the cation-induced water flow and the chloride-induced water flow in the opposite direction. In membranes of moderate to high H₂O content, co-ion transport is significant and the water-flow associated with co-ion movement must be determined if the contribution of the counter-ion ([EO]_cation) to the (EO _s) is to be found. Cl-ion induced water flow was determined by assuming an identity of K and Cl ions. [EO]_cation increased as the hydrated radii of the cations increased and for any particular cation [EO]_cation was at least 100% greater in the 60% hydrated membrane than in the 43% hydrated membrane. The current-induced water flow was found to be composed of both an electroosmotic and an osmotic component. The latter represented between 10 and 40% of the total water flow.Presented in part before the American Physiological Society at the 54^th meeting of the F.A.S.E.B., Atlantic City, N.J., April, 1970.     

Factors that influence the cutaneous synthesis and dietary sources of vitamin D

The major sources of vitamin D for most humans are casual exposure of the skin to solar ultraviolet B (UVB; 290-315 nm) radiation and from dietary intake. The cutaneous synthesis of vitamin D is a function of skin pigmentation and of the solar zenith angle which depends on latitude, season, and time of day. In order to mimic the natural environment of skin to sunlight exposure, we therefore measured serum 25-hydroxyvitamin D levels in volunteers with different skin types following repeated UV irradiation. Because melanin pigment in human skin competes for and absorbs the UVB photons responsible for the photolysis of 7-dehydrocholesterol to previtamin D3, we also studied the effect of skin pigmentation on previtamin D3 production in a human skin model by exposing type II and type V skin samples to noon sunlight in June when the solar zenith angle is most acute. Vitamin D is rare in food. Among the vitamin D-rich food, oily fish are considered to be one of the best sources. Therefore, we analyzed the vitamin D content in several commonly consumed oily and non-oily fish. The data showed that farmed salmon had a mean content of vitamin D that was approximately 25% of the mean content found in wild caught salmon from Alaska, and that vitamin D2 was found in farmed salmon, but not in wild caught salmon. The results provide useful global guidelines for obtaining sufficient vitamin D3 by cutaneous synthesis and from dietary intake to prevent vitamin D deficiency and its health consequences, ensuing illness, especially, bone fractures in the elderly.     

Structure of dipalmitoylphosphatidylcholine/cholesterol bilayer at low and high cholesterol concentrations: molecular dynamics simulation.

By using molecular dynamics simulation technique we studied the changes occurring in membranes constructed of dipalmitoylphosphatidylcholine (DPPC) and cholesterol at 8:1 and 1:1 ratios. We tested two different initial arrangements of cholesterol molecules for a 1:1 ratio. The main difference between two initial structures is the average number of nearest-neighbor DPPC molecules around the cholesterol molecule. Our simulations were performed at constant temperature (T = 50 degrees C) and pressure (P = 0 atm). Durations of the runs were 2 ns. The structure of the DPPC/cholesterol membrane was characterized by calculating the order parameter profiles for the hydrocarbon chains, atom distributions, average number of gauche defects, and membrane dipole potentials. We found that adding cholesterol to membranes results in a condensing effect: the average area of membrane becomes smaller, hydrocarbon chains of DPPC have higher order, and the probability of gauche defects in DPPC tails is lower. Our results are in agreement with the data available from experiments.     

Lessons from the Tōhoku tsunami: A model for island avifauna conservation prioritization

Earthquake‐generated tsunamis threaten coastal areas and low‐lying islands with sudden flooding. Although human hazards and infrastructure damage have been well documented for tsunamis in recent decades, the effects on wildlife communities rarely have been quantified. We describe a tsunami that hit the world's largest remaining tropical seabird rookery and estimate the effects of sudden flooding on 23 bird species nesting on Pacific islands more than 3,800 km from the epicenter. We used global positioning systems, tide gauge data, and satellite imagery to quantify characteristics of the Tōhoku earthquake‐generated tsunami (11 March 2011) and its inundation extent across four Hawaiian Islands. We estimated short‐term effects of sudden flooding to bird communities using spatially explicit data from Midway Atoll and Laysan Island, Hawai'i. We describe variation in species vulnerability based on breeding phenology, nesting habitat, and life history traits. The tsunami inundated 21%–100% of each island's area at Midway Atoll and Laysan Island. Procellariformes (albatrosses and petrels) chick and egg losses exceeded 258,500 at Midway Atoll while albatross chick losses at Laysan Island exceeded 21,400. The tsunami struck at night and during the peak of nesting for 14 colonial seabird species. Strongly philopatric Procellariformes were vulnerable to the tsunami. Nonmigratory, endemic, endangered Laysan Teal (Anas laysanensis) were sensitive to ecosystem effects such as habitat changes and carcass‐initiated epizootics of avian botulism, and its populations declined approximately 40% on both atolls post‐tsunami. Catastrophic flooding of Pacific islands occurs periodically not only from tsunamis, but also from storm surge and rainfall; with sea‐level rise, the frequency of sudden flooding events will likely increase. As invasive predators occupy habitat on higher elevation Hawaiian Islands and globally important avian populations are concentrated on low‐lying islands, additional conservation strategies may be warranted to increase resilience of island biodiversity encountering tsunamis and rising sea levels.     

Root Architecture Responses: In Search of Phosphate

Soil phosphate represents the only source of phosphorus for plants and, consequently, is its entry into the trophic chain. This major component of nucleic acids, phospholipids, and energy currency of the cell (ATP) can limit plant growth because of its low mobility in soil. As a result, root responses to low phosphate favor the exploration of the shallower part of the soil, where phosphate tends to be more abundant, a strategy described as topsoil foraging. We will review the diverse developmental strategies that can be observed among plants by detailing the effect of phosphate deficiency on primary and lateral roots. We also discuss the formation of cluster roots: an advanced adaptive strategy to cope with low phosphate availability observed in a limited number of species. Finally, we will put this work into perspective for future research directions.Plant embryogenesis generates a very primitive developmental blueprint with two apical meristems (shoot and root) that, unlike in animals, do not reflect the anatomy of the adult organism. The ability to form new organs is maintained throughout their lifecycle because of the sustained activity of these meristems as well as the presence of dedicated cells that dedifferentiate and generate new meristems. The continuous nature of plant development associated with their sessile lifestyle results in a strong dependency on their immediate environment. As a result, the study of plant development must not only focus on the fundamental molecular and cellular mechanisms but also, integrate their ability to perceive and respond to the environment. In this regard, plant root systems represent a good model, because they have a high level of developmental plasticity in response to water, nutrients, gravity, and mechanical characteristics of the soil as well as biotic interactions.Among the essential nutrients for plant growth and development, phosphorus is a key component of nucleic acids and phospholipids and present in soil in the form of either inorganic phosphate (Pi) or organophosphates. The former strongly interacts with divalent and trivalent cations. The latter has to be hydrolyzed to release phosphate for root uptake. The high sorption capacity of phosphate to soil particles results in a very low mobility and availability for uptake by plants. Therefore, the capacity of plants to find an adequate phosphate supply is directly correlated with their ability to explore the soil. Correspondingly, phosphorus deficiency induces changes in root system architecture as a key adaptive mechanism. A general strategy has been described under the term topsoil foraging that favors a shallower root system to explore the upper part of the soil, where phosphate tends to be more available because of the presence of organic matter and animal excrements. Although this term was first introduced to describe root system adaptation in bean (Phaseolus vulgaris; Lynch and Brown, 2001), the set of responses behind the topsoil foraging strategy has now been described in many other species (Panigrahy et al., 2009; Péret et al., 2011; Li et al., 2012; Shi et al., 2013). We will give an up-to-date overview of recent publications on developmental adaptations to low phosphate observed in diverse monocot and dicot species by focusing on the responses of the primary root (PR) and lateral roots. Finally, we will describe the evolutionarily advanced developmental adaptation to low phosphorus that has been found in several plant families’ (i.e. cluster or proteoid) root formation.     

An enzymatic fluorescent assay for the quantification of phosphite in a microtiter plate format

A sensitive fluorometric assay for the quantification of phosphite has been developed. The assay uses the enzymatic oxidation of phosphite to phosphate by a recombinant phosphite dehydrogenase with NAD⁺ as cosubstrate to produce the highly fluorescent reaction product resorufin. The optimized assay can be carried out in a 96-well microtiter plate format for high-throughput screening purposes and has a detection limit of 0.25 nmol phosphite. We used the method to quantify phosphite levels in plant tissue extracts and to determine phosphite dehydrogenase activity in transgenic plants. The assay is suitable for other biological or environmental samples. Because phosphite is a widely used fungicide to protect plants from pathogenic oomycetes, the assay provides a cost-effective and easy-to-use method to monitor the fate of phosphite following application.