scholarly journals Intake of Radionuclides in the Trees of Fukushima Forests 4. Binding of Radioiodine to Xyloglucan

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 957 ◽  
Author(s):  
Miki Nonaka ◽  
Chisato Yasukawa ◽  
Shoko Aoki ◽  
Masateru Itakura ◽  
Stefan Willför ◽  
...  

The 1,4-linked glucans such as xyloglucan and amylose are known to form a complex with iodine/iodide ions and to also be precipitated with CaCl2 in the presence of iodine. Here, we show that iodine gas could be specifically incorporated into xyloglucan. Furthermore, we show that [125I]I2 gas is, over time, incorporated at high levels into the entire outer surface of poplar seedlings but that spraying seedlings with abscisic acid to close stomata decreases the incorporation of the gas. There was less incorporation of the gas in a transgenic poplar overexpressing xyloglucanase at the early stages when compared with a wild type. This shows that xyloglucan serves as a key absorber of iodine gas into a plant body. After individual leaves of cultured seedlings were exposed to the gas for 30 min, no radioiodine was emitted from those leaves over the following two weeks, indicating that no turnover occurs in radioiodine once it is bound to the polysaccharides in plant tissues. We conclude that forest trees could serve as one of the largest enormous capture systems for the radioiodine fallout following the nuclear power plant accident in Fukushima.

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1247-1255 ◽  
Author(s):  
Eiji Nambara ◽  
Masaharu Suzuki ◽  
Suzanne Abrams ◽  
Donald R McCarty ◽  
Yuji Kamiya ◽  
...  

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 885
Author(s):  
Takafumi Shimizu ◽  
Yuri Kanno ◽  
Hiromi Suzuki ◽  
Shunsuke Watanabe ◽  
Mitsunori Seo

The plant hormone abscisic acid (ABA) is actively synthesized in vascular tissues and transported to guard cells to promote stomatal closure. Although several transmembrane ABA transporters have been identified, how the movement of ABA within plants is regulated is not fully understood. In this study, we determined that Arabidopsis NPF4.6, previously identified as an ABA transporter expressed in vascular tissues, is also present in guard cells and positively regulates stomatal closure in leaves. We also found that mutants defective in NPF5.1 had a higher leaf surface temperature compared to the wild type. Additionally, NPF5.1 mediated cellular ABA uptake when expressed in a heterologous yeast system. Promoter activities of NPF5.1 were detected in several leaf cell types. Taken together, these observations indicate that NPF5.1 negatively regulates stomatal closure by regulating the amount of ABA that can be transported from vascular tissues to guard cells.


2000 ◽  
Vol 83 (2) ◽  
pp. 998-1009 ◽  
Author(s):  
Daniel Kuebler ◽  
Mark A. Tanouye

In a given population, certain individuals are much more likely to have seizures than others. This increase in seizure susceptibility can lead to spontaneous seizures, such as seen in idiopathic epilepsy, or to symptomatic seizures that occur after insults to the nervous system. Despite the frequency of these seizure disorders in the human population, the genetic and physiological basis for these defects remains unclear. The present study makes use of Drosophila as a potentially powerful model for understanding seizure susceptibility in humans. In addition to the genetic and molecular advantages of using Drosophila, it has been found that seizures in Drosophila share much in common with seizures seen in humans. However, the most powerful aspect of this model lies in the ability to accurately measure seizure susceptibility across genotypes and over time. In the current study seizure susceptibility was quantified in a variety of mutant and wild-type strains, and it was found that genetic mutations can modulate susceptibility over an extremely wide range. This genetic modulation of seizure susceptibility apparently occurs without affecting the threshold of individual neurons. Seizure susceptibility also varied depending on the experience of the fly, decreasing immediately after a seizure and then gradually increasing over time. A novel phenomenon was also identified in which seizures are suppressed after certain high-intensity stimuli. These results demonstrate the utility of Drosophila as a model system for studying human seizure disorders and provide insights into the possible mechanisms by which seizure susceptibility is modified.


1985 ◽  
Vol 63 (9) ◽  
pp. 1582-1585 ◽  
Author(s):  
Leslie G. Hickok

Abscisic acid normally inhibits growth and male sexual differentiation (antheridia formation) in gametophytes of the fern Ceratopteris. Abscisic acid resistant mutants show increased growth and sexual differentiation in comparison with the wild type when cultured in the presence of abscisic acid. Two different mutants that confer resistance to the effects of abscisic acid have been fully characterized. One shows moderate resistance and the other strong resistance. The mutations involve separate but linked loci. Recombination between the loci yields double mutant (cis) recombinants that exhibit additive effects and show exceptional levels of abscisic acid resistance.


2018 ◽  
Vol 10 (3) ◽  
pp. 7
Author(s):  
Xiaolin Wang ◽  
Ningning Zhang ◽  
Jiakun Yan

With a varied physical environment, plants have developed specific mechanisms that allow them to rapidly perceive and respond to stresses in the environment. As one of many pathways conserved in a long time evolution, the abscisic acid (ABA) signaling pathway has been identified as a central regulator to control gene expression and generate physiological adaptation to various stressful conditions in plant. As abscisic acid receptors, PYR/PYL/RCARs have been proved to regulate stomatal closure. Here we detected the root cell hydraulic conductivity and the aquaporin expression under treatment of exogenous ABA in wild-type and pyr1/pyl1/pyl2/pyl4 mutant Arabidopsis using cell pressure probe and qRT-PCR technology. The results showed that PYR/PYL/RCAR receptors regulate root cell hydraulic conductivity through activating aquaporin expression. Lastly, we discussed how plants maintain water balance combined with the data obtained from published articles.


2021 ◽  
Vol 133 ◽  
pp. 105015
Author(s):  
Mario Martínez-Córcoles ◽  
Inés Tomás ◽  
Francisco J. Gracia ◽  
José M. Peiró

Author(s):  
Simon Fernandez ◽  
Laura Militello ◽  
Christen Sushereba ◽  
David Bahner ◽  
Michael Barrie ◽  
...  

We propose a toolkit for objectively evaluating the effectiveness of new technologies for improving human cognitive performance. In complex socio-technical systems such as nuclear power generation and air traffic management, garden path scenarios have been effectively used to anchor initial inaccurate hypotheses that are then monitored for movement towards the correct hypotheses as increasing evidence over time makes it easier to change the diagnosis. The time to come to an accurate diagnosis in a well-crafted simulation scenario with an initial inaccurate anchor hypothesis is an objective, repeatable measure of performance for the macrocognition function of sensemaking. The time to verbalize the recognition of critical cues, which becomes increasingly less subtle over time, as well as the time to move from the inaccurate diagnosis at one of the correct diagnoses in the complete diagnostic set can all be reliably measured and compared in an across-subject study design. Modifications with conceptually matched scenarios using within-subject designs can also be employed if asymmetric learning effects are managed.


2020 ◽  
Vol 21 (4) ◽  
pp. 1546 ◽  
Author(s):  
Olga A. Andrzejczak ◽  
Jesper F. Havelund ◽  
Wei-Qing Wang ◽  
Sergey Kovalchuk ◽  
Christina E. Hagensen ◽  
...  

Overexpression of phytoglobins (formerly plant hemoglobins) increases the survival rate of plant tissues under hypoxia stress by the following two known mechanisms: (1) scavenging of nitric oxide (NO) in the phytoglobin/NO cycle and (2) mimicking ethylene priming to hypoxia when NO scavenging activates transcription factors that are regulated by levels of NO and O2 in the N-end rule pathway. To map the cellular and metabolic effects of hypoxia in barley (Hordeum vulgare L., cv. Golden Promise), with or without priming to hypoxia, we studied the proteome and metabolome of wild type (WT) and hemoglobin overexpressing (HO) plants in normoxia and after 24 h hypoxia (WT24, HO24). The WT plants were more susceptible to hypoxia than HO plants. The chlorophyll a + b content was lowered by 50% and biomass by 30% in WT24 compared to WT, while HO plants were unaffected. We observed an increase in ROS production during hypoxia treatment in WT seedlings that was not observed in HO seedlings. We identified and quantified 9694 proteins out of which 1107 changed significantly in abundance. Many proteins, such as ion transporters, Ca2+-signal transduction, and proteins related to protein degradation were downregulated in HO plants during hypoxia, but not in WT plants. Changes in the levels of histones indicates that chromatin restructuring plays a role in the priming of hypoxia. We also identified and quantified 1470 metabolites, of which the abundance of >500 changed significantly. In summary the data confirm known mechanisms of hypoxia priming by ethylene priming and N-end rule activation; however, the data also indicate the existence of other mechanisms for hypoxia priming in plants.


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