How plants tell the time.
Ontology highlight
ABSTRACT:
SUBMITTER: Gardner MJ
PROVIDER: S-EPMC1479754 | biostudies-other | 2006 Jul
REPOSITORIES: biostudies-other
Similar Datasets
Project description:An endogenous rhythm synchronized to dawn cannot time photosynthesis-linked genes to peak consistently at noon since the interval between sunrise and noon changes seasonally. In this study, a solar clock model that circumvents this limitation is proposed using two daily timing references synchronized to noon and midnight. Other rhythmic genes that are not directly linked to photosynthesis, and which peak at other times, also find an adaptive advantage in entrainment to the solar rhythm.Fourteen datasets extracted from three published papers were used in a meta-analysis to examine the cyclic behaviour of the Arabidopsis thaliana photosynthesis-related gene CAB2 and the clock oscillator genes TOC1 and LHY in T cycles and N-H cycles.Changes in the rhythms of CAB2, TOC1 and LHY in plants subjected to non-24-h light:dark cycles matched the hypothesized changes in their behaviour as predicted by the solar clock model, thus validating it. The analysis further showed that TOC1 expression peaked ?5·5?h after mid-day, CAB2 peaked close to noon, while LHY peaked ?7·5?h after midnight, regardless of the cycle period, the photoperiod or the light:dark period ratio. The solar clock model correctly predicted the zeitgeber timing of these genes under 11 different lighting regimes comprising combinations of seven light periods, nine dark periods, four cycle periods and four light:dark period ratios. In short cycles that terminated before LHY could be expressed, the solar clock correctly predicted zeitgeber timing of its expression in the following cycle.Regulation of gene phases by the solar clock enables the plant to tell the time, by which means a large number of genes are regulated. This facilitates the initiation of gene expression even before the arrival of sunrise, sunset or noon, thus allowing the plant to 'anticipate' dawn, dusk or mid-day respectively, independently of the photoperiod.
| S-EPMC4479757 | biostudies-literature
Project description:Even the simplest choices can prompt decision-makers to balance their preferences against other, more pragmatic considerations like price. Thus, discerning people's preferences from their decisions creates theoretical, empirical, and practical challenges. The current paper addresses these challenges by highlighting some specific circumstances in which the amount of time that people spend examining potential purchase items (i.e., viewing time) can in fact reveal their preferences. Our model builds from the gazing literature, in a purchasing context, to propose that the informational value of viewing time depends on prices. Consistent with the model's predictions, four studies show that when prices are absent or moderate, viewing time provides a signal that is consistent with a person's preferences and purchase intentions. When prices are extreme or consistent with a person's preferences, however, viewing time is a less reliable predictor of either. Thus, our model highlights a price-contingent "viewing bias," shedding theoretical, empirical, and practical light on the psychology of preferences and visual attention, and identifying a readily observable signal of preference.
| S-EPMC4291227 | biostudies-literature
Project description:Young children are devoting more and more time to playing on handheld touchscreen devices (e.g., iPads). Though thousands of touchscreen apps are claimed to be "educational," there is a lack of sufficient evidence examining the impact of touchscreens on children's learning outcomes. In the present study, the two questions we focused on were (a) whether using a touchscreen was helpful in teaching children to tell time, and (b) to what extent young children could transfer what they had learned on the touchscreen to other media. A pre- and post-test design was adopted. After 10 min of exposure to an iPad touchscreen app designed to teach time, three groups of 5- to 6-year-old children (N = 65) were, respectively, tested with an iPad touchscreen, a toy clock or a drawing of a clock on paper. The results revealed that post-test scores in the iPad touchscreen test group were significantly higher than those at pre-test, indicating that the touchscreen itself could provide support for young children's learning. Similarly, regardless of being tested with a toy clock or paper drawing, children's post-test performance was also better than pre-test, suggesting that children could transfer what they had learned on an iPad touchscreen to other media. However, comparison among groups showed that children tested with the paper drawing underperformed those tested with the other two media. The theoretical and practical implications of the results, as well as limitations of the present study, are discussed.
| S-EPMC5112279 | biostudies-literature
Project description:Global warming is strongly affecting the maritime Antarctica climate and the consequent melting of perennial snow and ice covers resulted in increased colonization by plants. Colobanthus quitensis is a vascular plant highly adapted to the harsh environmental conditions of Antarctic Peninsula and understanding how the plant is responding to global warming is a new challenging target for modern cell physiology. To this aim, we performed differential proteomic analysis on C. quitensis plants grown in natural conditions compared to plants grown for one year inside open top chambers (OTCs) which determine an increase of about 4 °C at midday, mimicking the effect of global warming. A thorough analysis of the up- and downregulated proteins highlighted an extensive metabolism reprogramming leading to enhanced photoprotection and oxidative stress control as well as reduced content of cell wall components. Overall, OTCs growth seems to be advantageous for C. quitensis plants which could benefit from a better CO2 diffusion into the mesophyll and a reduced ROS-mediated photodamage.
| S-EPMC8392395 | biostudies-literature
Project description:Pediatricians are frequently asked to address parents' behavioral concerns. Time out (TO) is one of the few discipline strategies with empirical support and is recommended by the American Academy of Pediatrics. However, correctly performed, TO can be a complex procedure requiring training difficult to provide in clinic due to time and cost constraints. The Internet may be a resource for parents to supplement information provided by pediatricians. The present study included evaluation of information on TO contained in websites frequently accessed by parents. It was hypothesized that significant differences exist between the empirically supported parameters of TO and website-based information.Predefined search terms were entered into commonly used search engines. The information contained in each webpage (n = 102) was evaluated for completeness and accuracy based on research on TO. Data were also collected on the consistency of information about TO on the Internet.None of the pages reviewed included accurate information about all empirically supported TO parameters. Only 1 parameter was accurately recommended by a majority of webpages. Inconsistent information was found within 29% of the pages. The use of TO to decrease problem behavior was inaccurately portrayed as possibly or wholly ineffective on 30% of webpages.A parent searching for information about TO on the Internet will find largely incomplete, inaccurate, and inconsistent information. Since nonadherence to any 1 parameter will decrease the efficacy of TO, it is not recommended that pediatricians suggest the Internet as a resource for supplemental information on TO. Alternative recommendations for pediatricians are provided.
| S-EPMC4179870 | biostudies-literature
Project description:ObjectiveThis short communication investigates the usefulness of time-use measures to validate subjective health measures such as self-reported health (SRH). It does this by examining time-use patterns and SRH among middle-age adults in the United States distinguished by race/ethnicity and with additional attention to differences in responses based on language of interview for Hispanics.MethodsData for this study come from the 2013-2016 American Time Use Survey. We calculated average time-use for personal care; housework; paid work; leisure; volunteering/travel; caregiving; and education for every racial/ethnic group differentiating by SRH for 27,063 adults aged 25-64 years. A series of ANOVAs were computed to assess differences in time-use by SRH.ResultsNon-Hispanic whites and non-Hispanic Blacks who reported poor/fair SRH spent more time in personal care and leisure, and less time in paid work, volunteering/travel, caregiving and education, in comparison to those who reported Excellent/Very Good/Good SRH. Among Hispanics, differences by SRH were found for personal care, paid work, leisure and volunteering/travel. Hispanics who answered in English displayed partially similar patterns in SRH found for non-Hispanic whites and Blacks. Hispanics who answered in Spanish demonstrated differences in SRH in the areas of paid work, leisure and education, diverging from the other groups.ConclusionsTime-use differences by health status are consistent between non-Hispanic whites, non-Hispanic blacks, but not so for Hispanics. To some extent, Hispanics who answered in English have more comparable patterns to non-Hispanic whites and non-Hispanic Blacks than Spanish respondents. Caution should be exercised when self-reported health measures are used to compare diverse samples collected with surveys that are administered in different languages.
| S-EPMC8339336 | biostudies-literature
Project description:To our knowledge, there are no reports that demonstrate the use of host molecular markers for the purpose of detecting generic plant virus infection. Two approaches involving molecular indicators of virus infection in the model plant Arabidopsis thaliana were examined: the accumulation of small RNAs (sRNAs) using a microfluidics-based method (Bioanalyzer); and the transcript accumulation of virus-response related host plant genes, suppressor of gene silencing 3 (AtSGS3) and calcium-dependent protein kinase 3 (AtCPK3) by reverse transcriptase-quantitative PCR (RT-qPCR). The microfluidics approach using sRNA chips has previously demonstrated good linearity and good reproducibility, both within and between chips. Good limits of detection have been demonstrated from two-fold 10-point serial dilution regression to 0.1 ng of RNA. The ratio of small RNA (sRNA) to ribosomal RNA (rRNA), as a proportion of averaged mock-inoculation, correlated with known virus infection to a high degree of certainty. AtSGS3 transcript decreased between 14- and 28-days post inoculation (dpi) for all viruses investigated, while AtCPK3 transcript increased between 14 and 28 dpi for all viruses. A combination of these two molecular approaches may be useful for assessment of virus-infection of samples without the need for diagnosis of specific virus infection.
| S-EPMC8777591 | biostudies-literature
Project description:In a recent comprehensive investigation, we largely failed to identify significant genetic markers associated with P3 amplitude or to corroborate previous associations between P3 and specific single nucleotide polymorphisms (SNPs) or genes. In the present study we extended this line of investigation to examine time-frequency (TF) activity and intertrial phase coherence (ITPC) in the P3 time window, both of which are associated with P3 amplitude. Previous genome-wide research has reported associations between P3-related theta and delta activity and individual genetic variants. A large, population-based sample of 4211 subjects, comprising male and female adolescent twins and their parents, was genotyped for 527,828 single nucleotide polymorphisms (SNPs), from which over six million SNPs were accurately imputed. Heritability estimates were greater for TF energy than ITPC, whether based on biometric models or the combined influence of all measured SNPs (derived from genome-wide complex trait analysis). The magnitude of overlap in the specific SNPs associated with delta energy and ITPC and P3 amplitude was significant. A genome-wide analysis of all SNPs, accompanied by an analysis of approximately 17,600 genes, indicated a region of chromosome 2 around TEKT4 that was significantly associated with theta ITPC. Analysis of candidate SNPs and genes previously reported to be associated with P3 or related phenotypes yielded one association surviving correction for multiple tests: between theta energy and CRHR1. However, we did not obtain significant associations for SNPs implicated in previous genome-wide studies of TF measures. Identifying specific genetic variants associated with P3 amplitude remains a challenge.
| S-EPMC5517132 | biostudies-literature
Project description:RNA samples of each group, extracted from PBMCs (Peripheral blood mononuclear cell) , were hybridized on two dye array. Within groups and between groups analyses to identify canonical pathways and enriched biological annotations were conducted.
2023-05-01 | GSE160899 | GEO