Morningness: protective factor for sleep-related and emotional problems in childhood and adolescence?

The relationship between morningness/eveningness, sleep, and psychological problems is well documented in adults as well as in adolescents. However, research on the circadian orientation and its concomitants in younger children is scarce. The authors investigated the distribution of morningness/eveningness and its connection to sleeping and psychological problems in 91 children and 151 adolescents in Austria. The authors found that morning (M) types had less sleep-related and psychological problems than intermediate (I) and evening (E) types, respectively. Among children, M-types suffered less from daytime sleepiness (females: χ(2)((2))?= 8.1, p =?.017; males: χ(2)((2))?= 14.8, p =?.001). Among adolescents, M-types showed fewer sleep-wake problems (females: χ(2)((2))?= 17.5, p 相似文献   

Influence of root and leaf traits on the uptake of nutrients in cover crops

Plant and Soil - The objectives of this study were to determine the spatial structure of soil respiration (Rs) in a naturally-regenerated longleaf pine forest and to assess the ecological factors...     

Glutamate Uptake Is Stimulated by Extracellular S100B in Hippocampal Astrocytes

Summary  

Integrating frugivory and animal movement: a review of the evidence and implications for scaling seed dispersal

General principles about the consequences of seed dispersal by animals for the structure and dynamics of plant populations and communities remain elusive. This is in part because seed deposition patterns emerge from interactions between frugivore behaviour and the distribution of food resources, both of which can vary over space and time. Here we advocate a frugivore‐centred, process‐based, synthetic approach to seed dispersal research that integrates seed dispersal ecology and animal movement across multiple spatio‐temporal scales. To guide this synthesis, we survey existing literature using paradigms from seed dispersal and animal movement. Specifically, studies are discussed with respect to five criteria: selection of focal organisms (animal or plant); measurement of animal movement; characterization of seed shadow; animal, plant and environmental factors included in the study; and scales of the study. Most studies focused on either frugivores or plants and characterized seed shadows directly by combining gut retention time with animal movement data or indirectly by conducting maternity analysis of seeds. Although organismal traits and environmental factors were often measured, they were seldom used to characterize seed shadows. Multi‐scale analyses were rare, with seed shadows mostly characterized at fine spatial scales, over single fruiting seasons, and for individual dispersers. Novel animal‐ and seed‐tracking technologies, remote environmental monitoring tools, and advances in analytical methods can enable effective implementation of a hierarchical mechanistic approach to the study of seed dispersal. This kind of mechanistic approach will provide novel insights regarding the complex interplay between the factors that modulate animal behaviour and subsequently influence seed dispersal patterns across spatial and temporal scales.     

Uptake of L-cystine via an ABC transporter contributes defense of oxidative stress in the L-cystine export-dependent manner in Escherichia coli

Intracellular thiols like L-cystine and L-cystine play a critical role in the regulation of cellular processes. Here we show that Escherichia coli has two L-cystine transporters, the symporter YdjN and the ATP-binding cassette importer FliY-YecSC. These proteins import L-cystine, an oxidized product of L-cystine from the periplasm to the cytoplasm. The symporter YdjN, which is expected to be a new member of the L-cystine regulon, is a low affinity L-cystine transporter (K _m = 1.1 μM) that is mainly involved in L-cystine uptake from outside as a nutrient. E. coli has only two L-cystine importers because ΔydjNΔyecS mutant cells are not capable of growing in the minimal medium containing L-cystine as a sole sulfur source. Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress. The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (K _m = 110 nM) in a manner dependent on FliY, the periplasmic L-cystine-binding protein. The double disruption of ydeD and fliY increased cellular levels of lipid peroxides. From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.     

Chasing Jenner's vaccine: revisiting cowpox virus classification

Cowpox virus (CPXV) is described as the source of the first vaccine used to prevent the onset and spread of an infectious disease. It is one of the earliest described members of the genus Orthopoxvirus, which includes the viruses that cause smallpox and monkeypox in humans. Both the historic and current literature describe "cowpox" as a disease with a single etiologic agent. Genotypic data presented herein indicate that CPXV is not a single species, but a composite of several (up to 5) species that can infect cows, humans, and other animals. The practice of naming agents after the host in which the resultant disease manifests obfuscates the true taxonomic relationships of "cowpox" isolates. These data support the elevation of as many as four new species within the traditional "cowpox" group and suggest that both wild and modern vaccine strains of Vaccinia virus are most closely related to CPXV of continental Europe rather than the United Kingdom, the homeland of the vaccine.     

Non-stressful death of 23S rRNA mutant G2061C defective in puromycin reaction

Catalysis of peptide bond formation in the peptidyl transferase center is a major enzymatic activity of the ribosome. Mutations limiting peptidyl transferase activity are mostly lethal. However, cellular processes triggered by peptidyl transferase deficiency in the bacterial cell are largely unknown. Here we report a study of the lethal G2061C mutant of Escherichia coli 23S ribosomal RNA (rRNA). The G2061C mutation completely impaired the puromycin reaction and abolished formation of the active firefly luciferase in an in vitro translation system, while poly(U)- and short synthetic mRNA-directed peptidyl transferase reaction with aminoacylated tRNAs in vitro was seemingly unaffected. Study of the cellular proteome upon expression of the 23S rRNA gene carrying the G2061C mutation compared to cells expressing wild-type 23S rRNA gene revealed substantial differences. Most of the observed effects in the mutant were associated with reduced expression of stress response proteins and particularly proteins associated with the ppGpp-mediated stringent response.