Selenium supplementation and exercise: effect on oxidant stress in overweight adults

Both obesity and acute high‐intensity exercise increase oxidant stress levels. This study investigates whether selenium (Se) supplementation could be a potential effective therapy to reduce obesity‐associated oxidant stress and exercise‐induced oxidant stress. Ten normal‐weight (NW) (22.80 ± 0.41 kg/m²) and ten overweight (OW) healthy subjects (28.00 ± 0.81 kg/m²) were assessed during a randomized double‐blind Se supplementation study (200 µg sodium selenite/day for 3 weeks) with a 3‐week placebo control and inversion of treatment periods. Blood levels of lipid hydroperoxide (LH), superoxide dismutase (SOD), erythrocyte glutathione (GSH), and total antioxidant status (TAS), were measured at rest, pre‐, and postexercise (30 min 70% VO₂ max before and after treatment (pretreatment (week 0 and 12) and post‐treatment (week 3 or 15)). At rest, compared to placebo, Se supplementation had no significant effect on LH, SOD, GSH, and TAS levels. However, Se supplementation decreased LH levels in the OW group, immediately postexercise (?0.25 ± 0.12 µmol/l, P = 0.05) compared to placebo treatment. Postexercise, with or without Se supplementation, no changes in TAS, SOD, and GSH levels were observed in both the NW and OW group. This study has highlighted a potential benefit of Se in reducing LH levels postexercise in OW individuals. Given that oxidant stress is a predictor of coronary events, it is imperative to better understand oxidant stress‐related responses to lifestyle factors (in particular “high‐risk” population groups) and potential antioxidant therapy.     

Feather eating in individually caged hens which differ in their propensity to feather peck

Two experiments examined the responses of 16 individually caged laying hens to the presentation of feathers plucked from dead birds of the same genetic line. In the first experiment, hens known from a previous experiment to be either feather 'peckers' or 'non-peckers' (8 of each) were tested for their propensity to eat feathers in four 10min trials, in which they were offered fresh semiplumes measuring 4-6cm (length), one at a time, in front of their cage. Wide variation between birds was observed in numbers of feathers eaten, pecked, picked-up and manipulated. Fourteen out of 16 birds readily ate presented feathers on one or more occasion and both birds that ate no feathers were non-peckers. Peckers ate, picked-up and manipulated feathers significantly more often than did non-peckers (P<0.05, P<0.01 and P<0.01, respectively). A second experiment investigated the possibility that presence of preen (uropygial) oil might contribute to the attractiveness of feathers to eat. The same group of 16 pecker and non-pecker hens were offered a choice between 20 washed and 20 unwashed semiplumes, presented simultaneously in separate containers, in two 10min trials. Unwashed feathers were eaten, pecked and picked-up in preference to washed feathers by both peckers and non-peckers (P<0.05, P<0.01, and P<0.01, respectively), indicating an attraction towards unwashed feathers, or an avoidance of washed feathers for some reason. Peckers and non-peckers did not differ significantly in their preferences. These results provide evidence of a relationship between feather eating and feather pecking at an individual level. The finding that hens could distinguish between normal feathers and those treated in such a way as to alter their olfactory (but not visual) properties suggests olfactory cues may be of importance in determining the attractiveness of conspecific feathers.     

Anatomy and affinities of the petrified plants from the tertiary of chile V

Four species of dicotyledonous woods including three new species,Aextoxicoxylon harambouri sp. nov.,Myrceugenellites maytenoides sp. nov.,Laurelites doroteaensis sp. nov. andLaurinoxylon uniseriatum Gothan, were described from the Tertiary of Cerro Dorotea, Ultima Esperanza and Fuego Island, Chile. It was elucidated thatNothofagoxylon boureaui Salard from Cerro Dorotea is synonymous withLaurinoxylon uniseriatum from Antarctica. Consecutive number from the previous paper (Nishida, 1984). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 118 and contributions from Chiba University Botanical Expedition to the Andes No. 17. Supported by a Grant in-Aid for Overseas Scientific Survey from the Ministry of Education, Science and Culture Nos. 7405, 404114 and 62043014.     

Effects of qualitative and quantitative food restriction treatments on feeding motivational state and general activity level of growing broiler breeders

Growing broiler breeder chickens are fed restricted rations to limit body weight at sexual maturity. This experiment tested a proposal (Brouns, F., Edwards, S.A., English, P.R., 1994. Effect of dietary fibre and feeding system on activity and oral behaviour of group housed gilts. Appl. Anim. Behav. Sci. 39, 215-223.) that feeding motivation is reduced by using qualitative rather than quantitative food restriction, and it examined relationships among suppression of growth rate, feeding motivational state and general activity level. From 2 to 15 weeks of age, female broiler breeders were reared in six groups of 20, each with a different feeding treatment. The six treatments were: high and low levels of diet dilution (600-700 g/kg and 300-350 g/kg oat feed, ad libitum), appetite suppression (50-60 g/kg and 25-30 g/kg calcium propionate, ad libitum) and quantitative restriction (recommended daily ration and twice that amount). Birds were conditioned to an operant (PR1 schedule) feeding procedure with their respective treatment diets from 3 to 7 weeks, and this was used to measure feeding motivation in 12-min tests at three times of day (1000, 1300 and 1600 h) at 8, 10, 12 and 14 weeks. Proportions of time spent sitting were measured as an index of general inactivity in systematic observations at 9, 11, 13 and 15 weeks. Although the diet dilution and appetite suppression (qualitative) treatments did not limit growth rates as intended, they and the quantitative treatments produced a range of mean body weights to compare with feeding motivation whenever birds were tested. With body weight as a covariate, there were significant effects on numbers of operant responses in 12 min (the measure of feeding motivation) of weight, age, time of day and treatmentxtime interaction, but not treatment. Feeding motivation was positively correlated with suppression of growth rate, regardless of how that suppression was achieved. However, the experimental procedure required all test birds to be without food from 0900 or 0915 h, and motivation was lowest in the earliest (1000 h) test with qualitative but not quantitative treatments. Hence, there was some evidence that feeding motivation may be partially suppressed with qualitative food restriction; distinction can be made between short-term and longer-term feeding motivation. General activity level (inversely reflected by time spent sitting) was closely correlated positively with both suppression of growth rate and feeding motivation. As a fundamental relationship between feeding motivation and reduction of growth rate was not altered by using qualitative rather than quantitative food restriction, these results support an earlier conclusion (Savory, C.J., Hocking, P.M., Mann, J.S., Maxwell, M.H., 1996. Is broiler breeder welfare improved by using qualitative rather than quantitative food restriction to limit growth rate? Anim. Welfare 5, 105-127.) that broiler breeder welfare is not improved with qualitative restriction methods.     

Discrimination between NL1- and NL2-Mediated Nuclear Localization of the Glucocorticoid Receptor

Glucocorticoid receptor (GR) cycles between a free liganded form that is localized to the nucleus and a heat shock protein (hsp)-immunophilin-complexed, unliganded form that is usually localized to the cytoplasm but that can also be nuclear. In addition, rapid nucleocytoplasmic exchange or shuttling of the receptor underlies its localization. Nuclear import of liganded GR is mediated through a well-characterized sequence, NL1, adjacent to the receptor DNA binding domain and a second, uncharacterized motif, NL2, that overlaps with the ligand binding domain. In this study we report that rapid nuclear import (half-life [t_1/2] of 4 to 6 min) of agonist- and antagonist-treated GR and the localization of unliganded, hsp-associated GRs to the nucleus in G₀ are mediated through NL1 and correlate with the binding of GR to pendulin/importin α. By contrast, NL2-mediated nuclear transfer of GR occurred more slowly (t_1/2 = 45 min to 1 h), was agonist specific, and appeared to be independent of binding to importin α. Together, these results suggest that NL2 mediates the nuclear import of GR through an alternative nuclear import pathway. Nuclear export of GR was inhibited by leptomycin B, suggesting that the transfer of GR to the cytoplasm is mediated through the CRM1-dependent pathway. Inhibition of GR nuclear export by leptomycin B enhanced the nuclear localization of both unliganded, wild-type GR and hormone-treated NL1⁻ GR. These results highlight that the subcellular localization of both liganded and unliganded GRs is determined, at least in part, by a flexible equilibrium between the rates of nuclear import and export.     

Bcl-2 regulates amplification of caspase activation by cytochrome c

Caspases, a family of specific proteases, have central roles in apoptosis [1]. Caspase activation in response to diverse apoptotic stimuli involves the relocalisation of cytochrome c from mitochondria to the cytoplasm where it stimulates the proteolytic processing of caspase precursors. Cytochrome c release is controlled by members of the Bcl-2 family of apoptosis regulators [2] [3]. The anti-apoptotic members Bcl-2 and Bcl-xL may also control caspase activation independently of cytochrome c relocalisation or may inhibit a positive feedback mechanism [4] [5] [6] [7]. Here, we investigate the role of Bcl-2 family proteins in the regulation of caspase activation using a model cell-free system. We found that Bcl-2 and Bcl-xL set a threshold in the amount of cytochrome c required to activate caspases, even in soluble extracts lacking mitochondria. Addition of dATP (which stimulates the procaspase-processing factor Apaf-1 [8] [9]) overcame inhibition of caspase activation by Bcl-2, but did not prevent the control of cytochrome c release from mitochondria by Bcl-2. Cytochrome c release was accelerated by active caspase-3 and this positive feedback was negatively regulated by Bcl-2. These results provide evidence for a mechanism to amplify caspase activation that is suppressed at several distinct steps by Bcl-2, even after cytochrome c is released from mitochondria.     

Limitation of deuterium labelled methoximes as internal standards in the mass spectral analysis of prostaglandins

A reported method for the preparation of d3-methoxime derivatives as internal standards for prostaglandin assays by gas chromatography-mass spectrometry was evaluated. Sample derivatization resulted in 1.5-86% exchange of the d3-methoxime in a series of prostaglandins. Exchange was minimal when the methoxime was on the 5-membered ring; whereas, acyclic methoximes exhibited extensive exchange. Induced strain energy due to the steric interaction of the hydroxyl group and the C13-C20 alkyl side chain with the gem-dimethoxylamine transition state is offered as an explanation for the unusual stability of PGE2. The use of 18O exchange of the carboxylic acid function is presented as an alternative for the preparation of unavailable labelled eicosanoids.