食谱与空腹时间对基础呼气氢水平影响研究

目的　探讨食谱与空腹时间对基础呼气氢水平的影响,为制定适合国情的氢呼气试验饮食准备方案提供依据。方法　测定113 名自由饮食者清晨空腹呼气氢水平,调查前一天食物种类和进食时间,分析二者之间的关系。结果　在全部 113 名调查对象中,13 名空腹时间小于 12 小时和100 名空腹时间大于12 小时的空腹呼气氢分别为9.54ppm ±3.04ppm 和2.85ppm ±2.62ppm ,差异显著(t= 8.503,P= 0.000);在100 名空腹时间大于12 小时的调查对象中,17 名非产氢食物进食者和 50 名于早餐、5 名于中餐、27 名于晚餐进食产氢食物者空腹呼气氢分别为2.06ppm ±2.25ppm 和2.45ppm ±2.27ppm 、3.00ppm ±1.67ppm 、4.11ppm ±3.19ppm ,两种食谱比较,仅见晚餐产氢食物进食者显著性高于非产氢食进食者(P= 0.020)。结论　若进行氢呼气试验,忌产氢食物一天已足够,空腹时间则应大于12 小时     

Intergenerational and Genealogical Approaches for the Study of Longevity in the Saguenay-Lac-St-Jean Population

The mechanisms of longevity have been the subject of investigations for a number of years. Although the role of genetic factors is generally acknowledged, important questions persist regarding the relative impact of environmental exposures, lifestyle characteristics, and genes. The BALSAC population register offers a unique opportunity to study longevity from an intergenerational and genealogical point of view. Individuals from the Saguenay-Lac-St-Jean population who died at age 90 or older between 1950 and 1974 were selected from this database (n?=?576), along with a control group of individuals born in the same period who died between 50 and 75 years of age. For these subjects and controls, spouses’ ages at death and parental ages at death and at their birth were investigated using regression analysis. Genealogical reconstructions were carried out for each individual, and various analyses were performed on both groups. Both fathers’ and mothers’ mean ages at death were significantly higher among the longer-lived cases than among controls whereas spouses’ ages at death and parental ages at birth had no effect. Regression analysis confirmed the positive effect of both fathers’ and mothers’ age at death. Mean kinship coefficients for the parents’ generations displayed significant differences, indicating that kinship was higher among subjects than controls (this effect was stronger among the oldest 10% of the subjects). Frequencies and genetic contributions of ancestors were very similar for the two groups, and none of these ancestors appeared more likely to have introduced genetic variants involved in longevity patterns in this French Canadian population.     

The plant Apolipoprotein D ortholog protects <Emphasis Type="Italic">Arabidopsis</Emphasis> against oxidative stress

Background  

Lipocalins are a large and diverse family of small, mostly extracellular proteins implicated in many important functions. This family has been studied in bacteria, invertebrate and vertebrate animals but little is known about these proteins in plants. We recently reported the identification and molecular characterization of the first true lipocalins from plants, including the Apolipoprotein D ortholog AtTIL identified in the plant model Arabidopsis thaliana. This study aimed to determine its physiological role in planta.     

Nutrient enrichment and fisheries exploitation: interactive effects on estuarine living resources and their management

Both fisheries exploitation and increased nutrient loadings strongly affect fish and shellfish abundance and production in estuaries. These stressors do not act independently; instead, they jointly influence food webs, and each affects the sensitivity of species and ecosystems to the other. Nutrient enrichment and the habitat degradation it sometimes causes can affect sustainable yields of fisheries, and fisheries exploitation can affect the ability of estuarine systems to process nutrients. The total biomass of fisheries landings in estuaries and semi-enclosed seas tends to increase with nitrogen loadings in spite of hypoxia, but hypoxia and other negative effects of nutrient over-enrichment cause declines in individual species and in parts of systems most severely affected. More thoroughly integrated management of nutrients and fisheries will permit more effective management responses to systems affected by both stressors, including the application of fisheries regulations to rebuild stocks negatively affected by eutrophication. Reducing fishing mortality may lead to the recovery of depressed populations even when eutrophication contributes to population declines if actions are taken while the population retains sufficient reproductive potential. New advances in modeling, statistics, and technology promise to provide the information needed to improve the understanding and management of systems subject to both nutrient enrichment and fisheries exploitation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark     

Reconstruction of gross avian genome structure,organization and evolution suggests that the chicken lineage most closely resembles the dinosaur avian ancestor

Background

The availability of multiple avian genome sequence assemblies greatly improves our ability to define overall genome organization and reconstruct evolutionary changes. In birds, this has previously been impeded by a near intractable karyotype and relied almost exclusively on comparative molecular cytogenetics of only the largest chromosomes. Here, novel whole genome sequence information from 21 avian genome sequences (most newly assembled) made available on an interactive browser (Evolution Highway) was analyzed.

Results

Focusing on the six best-assembled genomes allowed us to assemble a putative karyotype of the dinosaur ancestor for each chromosome. Reconstructing evolutionary events that led to each species’ genome organization, we determined that the fastest rate of change occurred in the zebra finch and budgerigar, consistent with rapid speciation events in the Passeriformes and Psittaciformes. Intra- and interchromosomal changes were explained most parsimoniously by a series of inversions and translocations respectively, with breakpoint reuse being commonplace. Analyzing chicken and zebra finch, we found little evidence to support the hypothesis of an association of evolutionary breakpoint regions with recombination hotspots but some evidence to support the hypothesis that microchromosomes largely represent conserved blocks of synteny in the majority of the 21 species analyzed. All but one species showed the expected number of microchromosomal rearrangements predicted by the haploid chromosome count. Ostrich, however, appeared to retain an overall karyotype structure of 2n = 80 despite undergoing a large number (26) of hitherto un-described interchromosomal changes.

Conclusions

Results suggest that mechanisms exist to preserve a static overall avian karyotype/genomic structure, including the microchromosomes, with widespread interchromosomal change occurring rarely (e.g., in ostrich and budgerigar lineages). Of the species analyzed, the chicken lineage appeared to have undergone the fewest changes compared to the dinosaur ancestor.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1060) contains supplementary material, which is available to authorized users.     

Multilocus perspectives on the monophyly and phylogeny of the order Charadriiformes (Aves)

Background  

The phylogeny of shorebirds (Aves: Charadriiformes) and their putative sister groups was reconstructed using approximately 5 kilobases of data from three nuclear loci and two mitochondrial genes, and compared to that based on two other nuclear loci.     

Feeling the Insight: Uncovering Somatic Markers of the “aha” Experience

Whether internal insight can be recognized by experiencing (somatic feeling) remains an unexplored problem. This study investigated the issue by examining potential somatic markers of the “aha” experience occurring at the moment of sudden insight. Participants were required to solve a set of compound remote associates (CRA) problems and were simultaneously monitored via electrodermal and cardiovascular recordings. The “aha”-related psychological components and somatic markers were determined by contrasting insightful solutions with non-insightful solutions. Results showed that the “aha” experience was an amalgam entailing positive affects and approached cognition accompanied by a greater mean skin conductance response (mSCR) amplitude and a marginally accelerated heart rate than the “no-aha” one. These results confirm and extend findings of the multidimensionality of the “aha” feeling and offer the first direct evidence of somatic markers, particularly an electrodermal signature of an “aha” feeling, which suggests a sudden insight could likely be experienced by individuals’ external soma.     

Individual-based modelling of recruitment variability and biomass production of bay anchovy in mid-Chesapeake Bay

Production of bay anchovy Anchoa mitchilli is highest in the larval and juvenile stages. The interplay between vital rates, stage durations, prey resources, and anchovy abundance ultimately determines the relative magnitude of recruitment (which in the model varies by about three-fold) and of stage-specific production. Changes in adult seasonal spawning patterns that increase the number of larval survivors result in only a slight increase in overall production due to density-dependent decreases in growth rates of later life stages. Bay anchovy in the mid-Chesapeake Bay may reach a compensatory threshold during late summer-autumn as fish growth is affected by competition for food resources. Density dependence in the population is evident in the relationships between spawner-recruit, size-recruit, and production of larval or juvenile to young-of-the-year life stages. Density-dependent growth acts differentially upon the early life stage that exceeds the compensatory threshold in any given year, due either to environmental variability or population size, or both. This could explain partially the relatively low recruitment variability observed for this anchovy.     

Caco-2 Cell Line Used as an In Vitro Model to Study Cadmium Accumulation in Intestinal Epithelial Cells

¹⁰⁹Cd uptake was studied using the highly differentiated TC7 clone of Caco-2 cells as a model of human enterocyte function. Intracellular accumulation of 0.3 μm ¹⁰⁹Cd involved a rapid and a slow uptake phase, which resulted in complete equilibration (t _?= 17.3 ± 1.3 min) with an apparent in-to-out distribution ratio (α _e ) of 11.6 ± 0.8. The amplitude of the rapid phase (U ₀) and the rate of the slow phase (V) were similarly reduced in the less differentiated PF11 clone, but comparable α _e values were observed at equilibrium. In both clones, the t _? and α _e values increased and decreased, respectively, upon addition of unlabeled Cd to the uptake media. In TC7 cells, ¹⁰⁹Cd uptake at 1 min (U ₁) was unaffected by Ca concentrations four order of magnitude in excess, but both U ₀ and V demonstrated similar sensitivities to unlabeled Cd, Zn and sulfhydryl-reactive agents. Only U ₀ disappeared when EDTA was present in the wash solutions. U ₁ showed saturation kinetics and the data were found compatible with a model assuming rapid initial Cd binding and transport through a unique transport protein (K _m = 3.8 ± 0.7 μm). Cd efflux kinetics demonstrated partial reversibility in EDTA-containing solutions, suggesting that the taken up Cd might be both tightly and loosely bound to intracellular binding sites. However, the displacement of ¹⁰⁹Cd measured at 65 min failed to reveal this heterogeneity: the data were found compatible with a model equation assuming the presence of one class of high-capacity high-affinity binding sites. We conclude that a slow-transport fast-intracellular binding mechanism of Cd uptake best accounts for these results and that Cd transport most likely involves a carrier-type of protein unrelated to Ca absorption. Received: 19 January 1996/Revised: 23 January 1997