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71.
ABA-regulated promoter activity in stomatal guard cells 总被引:4,自引:0,他引:4
Jane E. Taylor Kirstie F. Renwick Alex A.R. Webb Martin R. McAinsh Antonella Furini Dorothea Bartels Ralph S. Quatrano William R. Marcotte Jr. Alistair M. Hetherington 《The Plant journal : for cell and molecular biology》1995,7(1):129-134
CDeT6-19 is an ABA-regulated gene which has been isolated from Craterostigma plantagineum . The CDeT6-19 gene promoter has been fused to the β- glucuronidase reporter gene ( GUS ) and used to stably transform Arabidopsis thaliana and Nicotiana tabacum . This construct has been shown to be expressed in stomatal guard cells and often in the adjacent epidermal cells of both species in response to both exogenous ABA and drought stress. These results indicate that the stomatal guard cell is competent to relay an ABA signal to the nucleus. In contrast GUS expression directed by the promoter from a predominantly seed-specific, ABA-regulated gene, Em , or the promoter from the ABA-regulated CDeT27-45 gene is not detectable in the epidermal or guard cells of tobacco or Arabidopsis in response to ABA. The fact that not all ABA-regulated gene promoters are active in stomatal guard cells suggests that effective transduction of the signal is dependent upon particular regions within the gene promoter or that guard cells lack all or part of the specific transduction apparatus required to couple the ABA signal to these promoters. This suggests that there are multiple ABA stimulus response coupling pathways. The identification of a regulatory sequence from an ABA-induced gene which is expressed in stomatal guard cells creates the possibility of examining the role of Ca2+ and other second messengers in ABA-induced gene expression. 相似文献
72.
Folkert Reck Alun Bermingham Johanne Blais Vladimir Capka Taryn Cariaga Anthony Casarez Richard Colvin Charles R. Dean Alex Fekete Wanben Gong Ellie Growcott Hongqiu Guo Adriana K. Jones Cindy Li Fengxia Li Xiaodong Lin Mika Lindvall Sara Lopez Qingming Zhu 《Bioorganic & medicinal chemistry letters》2018,28(4):748-755
Metallo-β-lactamases (MBLs), such as New Delhi metallo-β-lactamase (NDM-1) have spread world-wide and present a serious threat. Expression of MBLs confers resistance in Gram-negative bacteria to all classes of β-lactam antibiotics, with the exception of monobactams, which are intrinsically stable to MBLs. However, existing first generation monobactam drugs like aztreonam have limited clinical utility against MBL-expressing strains because they are impacted by serine β-lactamases (SBLs), which are often co-expressed in clinical isolates. Here, we optimized novel monobactams for stability against SBLs, which led to the identification of LYS228 (compound 31). LYS228 is potent in the presence of all classes of β-lactamases and shows potent activity against carbapenem-resistant isolates of Enterobacteriaceae (CRE). 相似文献
73.
Daniel Markewitz E. Conrad Lamon III Mercedes C. Bustamante Joaquin Chaves Ricardo O. Figueiredo Mark S. Johnson Alex Krusche Christopher Neill Jos�� S. O. Silva 《Biogeochemistry》2011,105(1-3):19-35
Stream discharge?Cconcentration relationships are indicators of terrestrial ecosystem function. Throughout the Amazon and Cerrado regions of Brazil rapid changes in land use and land cover may be altering these hydrochemical relationships. The current analysis focuses on factors controlling the discharge?Ccalcium (Ca) concentration relationship since previous research in these regions has demonstrated both positive and negative slopes in linear log10discharge?Clog10Ca concentration regressions. The objective of the current study was to evaluate factors controlling stream discharge?CCa concentration relationships including year, season, stream order, vegetation cover, land use, and soil classification. It was hypothesized that land use and soil class are the most critical attributes controlling discharge?CCa concentration relationships. A multilevel, linear regression approach was utilized with data from 28 streams throughout Brazil. These streams come from three distinct regions and varied broadly in watershed size (<1 to >106 ha) and discharge (10?5.7?C103.2 m3 s?1). Linear regressions of log10Ca versus log10discharge in 13 streams have a preponderance of negative slopes with only two streams having significant positive slopes. An ANOVA decomposition suggests the effect of discharge on Ca concentration is large but variable. Vegetation cover, which incorporates aspects of land use, explains the largest proportion of the variance in the effect of discharge on Ca followed by season and year. In contrast, stream order, land use, and soil class explain most of the variation in stream Ca concentration. In the current data set, soil class, which is related to lithology, has an important effect on Ca concentration but land use, likely through its effect on runoff concentration and hydrology, has a greater effect on discharge?Cconcentration relationships. 相似文献
74.
Alex D. Rogers Adam D. Leaché Kate L. Ciborowski Michael J. Polito Heather J. Lynch Michael J. Dunn Tom Hart 《Ecology and evolution》2016,6(6):1834-1853
Climate change, fisheries' pressure on penguin prey, and direct human disturbance of wildlife have all been implicated in causing large shifts in the abundance and distribution of penguins in the Southern Ocean. Without mark‐recapture studies, understanding how colonies form and, by extension, how ranges shift is challenging. Genetic studies, particularly focused on newly established colonies, provide a snapshot of colonization and can reveal the extent to which shifts in abundance and occupancy result from changes in demographic rates (e.g., reproduction and survival) or migration among suitable patches of habitat. Here, we describe the population structure of a colonial seabird breeding across a large latitudinal range in the Southern Ocean. Using multilocus microsatellite genotype data from 510 Gentoo penguin (Pygoscelis papua) individuals from 14 colonies along the Scotia Arc and Antarctic Peninsula, together with mitochondrial DNA data, we find strong genetic differentiation between colonies north and south of the Polar Front, that coincides geographically with the taxonomic boundary separating the subspecies P. p. papua and P. p. ellsworthii. Using a discrete Bayesian phylogeographic approach, we show that southern Gentoos expanded from a possible glacial refuge in the center of their current range, colonizing regions to the north and south through rare, long‐distance dispersal. Our findings show that this dispersal is important for new colony foundation and range expansion in a seabird species that ordinarily exhibits high levels of natal philopatry, though persistent oceanographic features serve as barriers to movement. 相似文献
75.
A number of 5′, N6- and C8, N6-disubstituted adenosine analogs was synthesized and tested for inhibition of trypanosomal glyceraldehyde 3-phosphate dehydrogenase. The most active compound, N6-(3-methyl-2-butenyl)-8-(2-thienyl)adenosine, had Ki of 9 μM and was marginally selective for the parasite enzyme. 相似文献
76.
77.
Stephen B. Pyecroft Anne-Maree Pearse Richmond Loh Kate Swift Kathy Belov Nolan Fox Erin Noonan Dane Hayes Alex Hyatt Lingfa Wang David Boyle Jeff Church Debra Middleton Robert Moore 《EcoHealth》2007,4(3):346-351
In the mid 1990s an emerging disease characterised by the development of proliferative lesions around the face of Tasmanian
devils (Sarcophilus harrisii) was observed. A multi-disciplinary approach was adopted to define the condition. Histopathological and transmission electron
microscopic examination combined with immunohistochemistry help define Devil Facial Tumour Disease (DFTD) as a neoplastic
condition of cells of neuroendocrine origin. Cytogenetic analysis of neoplastic tissue revealed it to be markedly different
from normal devil tissue and having a consistent karyotype across all tumours examined. Combined with evidence for Major histocompatability
(MHC) gene analysis there is significant evidence to confirm the tumour is a transmissible neoplasm. 相似文献
78.
Rømer Thomsen K Lou HC Joensson M Hyam JA Holland P Parsons CE Young KS Møller A Stein A Green AL Kringelbach ML Aziz TZ 《PloS one》2011,6(4):e18686
Emotion and reward have been proposed to be closely linked to conscious experience, but empirical data are lacking. The anterior cingulate cortex (ACC) plays a central role in the hedonic dimension of conscious experience; thus potentially a key region in interactions between emotion and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced-choice test. By manipulating the emotional valence (positive, neutral, negative) and the presentation time (16 ms, 32 ms, 80 ms) we measured the impact of these variables on conscious and subliminal (i.e. below threshold) processing. First, we tested normal participants using face and word stimuli. Results showed that participants were more confident and accurate when consciously seeing happy versus sad/neutral faces and words. When stimuli were presented subliminally, we found no effect of emotion. To investigate the neural basis of this impact of emotion, we recorded local field potentials (LFPs) directly in the ACC in a chronic pain patient. Behavioural findings were replicated: the patient was more confident and accurate when (consciously) seeing happy versus sad faces, while no effect was seen in subliminal trials. Mirroring behavioural findings, we found significant differences in the LFPs after around 500 ms (lasting 30 ms) in conscious trials between happy and sad faces, while no effect was found in subliminal trials. We thus demonstrate a striking impact of emotion on conscious experience, with positive emotional stimuli enhancing conscious reportability. In line with previous studies, the data indicate a key role of the ACC, but goes beyond earlier work by providing the first direct evidence of interaction between emotion and conscious experience in the human ACC. 相似文献
79.
Background
We study the evolutionary Prisoner''s Dilemma on two social networks substrates obtained from actual relational data.Methodology/Principal Findings
We find very different cooperation levels on each of them that cannot be easily understood in terms of global statistical properties of both networks. We claim that the result can be understood at the mesoscopic scale, by studying the community structure of the networks. We explain the dependence of the cooperation level on the temptation parameter in terms of the internal structure of the communities and their interconnections. We then test our results on community-structured, specifically designed artificial networks, finding a good agreement with the observations in both real substrates.Conclusion
Our results support the conclusion that studies of evolutionary games on model networks and their interpretation in terms of global properties may not be sufficient to study specific, real social systems. Further, the study allows us to define new quantitative parameters that summarize the mesoscopic structure of any network. In addition, the community perspective may be helpful to interpret the origin and behavior of existing networks as well as to design structures that show resilient cooperative behavior. 相似文献80.
María Pérez-Fernández Carole P. Elliott Alex Valentine José Antonio Oyola 《Journal of Plant Ecology》2019,12(6):949
Aims
Seeds ofRumex crispusfrom six provenances were studied in relation to their germination under drought and presence of nitrogen in the germination and emergence media. We also investigated whether adaptation to soil increases the ability of the species to colonize and establish in contrasting environments along a longitudinal gradient in western Spain by means of a reciprocal transplantation experiment. 相似文献