Heavy metal contamination has caused serious threats to surrounding fragile environments and human health. While the novel microbial-induced carbonate precipitation (MICP) technology in the recent ...years has been proven effective in improving material mechanical and durability properties, the mechanisms remedying heavy metal contamination still remain unclear. In this study, the potential of applying the MICP technology to the lead remediation under the effects of urease activity and calcium source was explored. The values of OD600 corresponding to the ureolytic bacterial activity, electrical conductivity (EC), urease activity (UA) and pH were applied to monitor the degree of urea hydrolysis. Further, the carbonate precipitations that possess different speciations and cannot be distinguished through test tube experiments were reproduced using the Visual MINTEQ software package towards verifying the validity of the proposed simulations, and revealing the mechanisms affecting the lead remediation efficiency. The findings summarised in this work give deep insights into lead-contaminated site remediation engineering.
Display omitted
•The potential of applying the novel biomineralisation to Pb removal is explored.•The intracellular urease and calcium source elevate the degree of urea hydrolysis.•The multilayer structure depresses the effect of Pb2+ and prevents their migration.
Summary
Although glutathione is well known for its reactive oxygen species (ROS) scavenging function and plays a protective role in biotic stress, its regulatory function in abiotic stress still ...remains to be elucidated. Our previous study showed that exogenously applied reduced glutathione (GSH) could improve abiotic stress tolerance in Arabidopsis. Here, we report that endogenously increased GSH also conferred tolerance to drought and salt stress in Arabidopsis. Moreover, both exogenous and endogenous GSH delayed senescence and flowering time. Polysomal profiling results showed that global translation was enhanced after GSH treatment and by the induced increase of GSH level by salt stress. By performing transcriptomic analyses of steady‐state and polysome‐bound mRNAs in GSH‐treated plants, we reveal that GSH has a substantial impact on translation. Translational changes induced by GSH treatment target numerous hormones and stress signaling molecules, which might contribute to the enhanced stress tolerance in GSH‐treated plants. Our translatome analysis also revealed that abscisic acid (ABA), auxin and jasmonic acid (JA) biosynthesis, as well as signaling genes, were activated during GSH treatment, which has not been reported in previously published transcriptomic data. Together, our data suggest that the increased glutathione level results in stress tolerance and global translational changes.
Significance Statement
The mechanisms by which recued glutathione (GSH) treatment leads to increased abiotic stress are poorly understood. Here we show that GSH treatment leads to translational changes of numerous hormones and stress signaling molecules, which might contribute to enhanced stress tolerance and growth.
Constituting approximately 10% of flowering plant species, orchids (Orchidaceae) display unique flower morphologies, possess an extraordinary diversity in lifestyle, and have successfully colonized ...almost every habitat on Earth. Here we report the draft genome sequence of Apostasia shenzhenica, a representative of one of two genera that form a sister lineage to the rest of the Orchidaceae, providing a reference for inferring the genome content and structure of the most recent common ancestor of all extant orchids and improving our understanding of their origins and evolution. In addition, we present transcriptome data for representatives of Vanilloideae, Cypripedioideae and Orchidoideae, and novel third-generation genome data for two species of Epidendroideae, covering all five orchid subfamilies. A. shenzhenica shows clear evidence of a whole-genome duplication, which is shared by all orchids and occurred shortly before their divergence. Comparisons between A. shenzhenica and other orchids and angiosperms also permitted the reconstruction of an ancestral orchid gene toolkit. We identify new gene families, gene family expansions and contractions, and changes within MADS-box gene classes, which control a diverse suite of developmental processes, during orchid evolution. This study sheds new light on the genetic mechanisms underpinning key orchid innovations, including the development of the labellum and gynostemium, pollinia, and seeds without endosperm, as well as the evolution of epiphytism; reveals relationships between the Orchidaceae subfamilies; and helps clarify the evolutionary history of orchids within the angiosperms.
ETHYLENE RESPONSE FACTOR 1 (ERF1) plays an important role in integrating hormone crosstalk and stress responses. Previous studies have shown that ERF1 is unstable in the dark and its degradation is ...mediated by UBIQUITIN-CONJUGATING ENZYME 18. However, whether there are other enzymes regulating ERF1's stability remains unclear. Here, we use various in vitro and in vivo biochemical, genetic and stress-tolerance tests to demonstrate that both CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and SUMO-CONJUGATING ENZYME 1 (SCE1) regulate the stability of ERF1. We also performed transcriptomic analyses to understand their common regulatory pathways. We show that COP1 mediates ERF1 ubiquitination in the dark while SCE1 mediates ERF1 sumoylation in the light. ERF1 stability is positively regulated by SCE1 and negatively regulated by COP1. Upon abiotic stress, SCE1 plays a positive role in stress defence by regulating the expression of ERF1's downstream stress-responsive genes, whereas COP1 plays a negative role in stress response. Moreover, ERF1 also promotes photomorphogenesis and the expression of light-responsive genes. Our study reveals the molecular mechanism of how COP1 and SCE1 counteract to regulate ERF1's stability and light-stress signalling crosstalk.
Reinforcing structural members and construction materials using recycled fibers has become popular in the past decades due to sustainable development concerns. The recycled fibers as soil ...reinforcement elements contribute to the increase in shear strength by distributing stresses exerted in the soil along the length of the recycled fibers. Loess, widely spread over the Chinese Loess Plateau, is featured with metastable structure, large porosity, and high water sensitivity. This study presents the results of applying the large-scale stress-controlled direct shear tests on the recycled straw fiber-reinforced loess. The formation mechanism of shearing behaviour enhancement of the loess by straw fiber inclusion is revealed. The associated strain-hardening behaviour can be manifested using the dilation angle or the difference in friction angle between the large-displacement friction angle and the peak friction angle. Further, the shear strength using the displacement-controlled direct shear tests presents good correspondence with that using the stress-controlled direct shear tests. The test results explore the potential of using the recycled straw fiber-reinforced loess to protect the fragile loess environment in the northwest of China.
The atomic level assembly of silver dendrite has never been disclosed despite the numerous studies published on fractal dendrite structures. We report for the first time an HRTEM investigation of the ...formation of atomic embryos (< 5 nm) and the self-assembly of atoms on an atomic plane of the tip of a dendrite arm. The mechanism of dendrite formation proceeds via the sequence of amorphous embryos aggregates (5-10 nm), nuclei, crystallites (10-20 nm), dendritelets (50-100 nm) and submicron dendrite protypes. The atomic plane is an entirely atomic-level zig-zag structure with d-spacing kink steps. The zig-zag structure triggers the self-assembly of atoms and thus directional growth to produce a dendrite arm with a high aspect ratio.
Substantial developments have been established in the past few years for enhancing the performance of brain-computer interface (BCI) based on steady-state visual evoked potential (SSVEP). The past ...SSVEP-BCI studies utilized different target frequencies with flashing stimuli in many different applications. However, it is not easy to recognize user's mental state changes when performing the SSVEP-BCI task. What we could observe was the increasing EEG power of the target frequency from the user's visual area. BCI user's cognitive state changes, especially in mental focus state or lost-in-thought state, will affect the BCI performance in sustained usage of SSVEP. Therefore, how to differentiate BCI users' physiological state through exploring their neural activities changes while performing SSVEP is a key technology for enhancing the BCI performance. In this study, we designed a new BCI experiment which combined working memory task into the flashing targets of SSVEP task using 12 Hz or 30 Hz frequencies. Through exploring the EEG activity changes corresponding to the working memory and SSVEP task performance, we can recognize if the user's cognitive state is in mental focus or lost-in-thought. Experiment results show that the delta (1-4 Hz), theta (4-7 Hz), and beta (13-30 Hz) EEG activities increased more in mental focus than in lost-in-thought state at the frontal lobe. In addition, the powers of the delta (1-4 Hz), alpha (8-12 Hz), and beta (13-30 Hz) bands increased more in mental focus in comparison with the lost-in-thought state at the occipital lobe. In addition, the average classification performance across subjects for the KNN and the Bayesian network classifiers were observed as 77% to 80%. These results show how mental state changes affect the performance of BCI users. In this work, we developed a new scenario to recognize the user's cognitive state during performing BCI tasks. These findings can be used as the novel neural markers in future BCI developments.
The fatty liver index (FLI) is an algorithm involving the waist circumference, body mass index, and serum levels of triglyceride and gamma-glutamyl transferase to identify fatty liver. Although some ...studies have attempted to validate the FLI, few studies have been conducted for external validation among Asians. We attempted to validate FLI to predict ultrasonographic fatty liver in Taiwanese subjects.
We enrolled consecutive subjects who received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009. Ultrasonography was applied to diagnose fatty liver. The ability of the FLI to detect ultrasonographic fatty liver was assessed by analyzing the area under the receiver operating characteristic (AUROC) curve.
Among the 29,797 subjects enrolled in this study, fatty liver was diagnosed in 44.5% of the population. Subjects with ultrasonographic fatty liver had a significantly higher FLI than those without fatty liver by multivariate analysis (odds ratio 1.045; 95% confidence interval, CI 1.044-1.047, p< 0.001). Moreover, FLI had the best discriminative ability to identify patients with ultrasonographic fatty liver (AUROC: 0.827, 95% confidence interval, 0.822-0.831). An FLI < 25 (negative likelihood ratio (LR-) 0.32) for males and <10 (LR- 0.26) for females rule out ultrasonographic fatty liver. Moreover, an FLI ≥ 35 (positive likelihood ratio (LR+) 3.12) for males and ≥ 20 (LR+ 4.43) for females rule in ultrasonographic fatty liver.
FLI could accurately identify ultrasonographic fatty liver in a large-scale population in Taiwan but with lower cut-off value than the Western population. Meanwhile the cut-off value was lower in females than in males.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Due to the monsoon climate, saline soils extensively spread over the arid or semi-arid area (e.g. NW China) and are featured with notable dissolution collapsibility and salt expandability. The ...features cause road hump and subgrade corrosion towards endangering the safety of passers. In this study, the microstructural evolution of the loess when subjected to alkaline and saline environments was investigated using a series of microscale tests, including scanning electron microscopic (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (SEM–EDS), and mercury intrusion porosimetry (MIP). The correspondence of the microstructural evolution with the macroscale mechanical properties using the reduced triaxial extension tests was studied. The test results showed that the alkaline and saline environments led to the microstructural evolution of the loess, involving the particle morphology, microstructural characteristics, pore distribution, and directionality of the pores. The increasing thickness of the diffuse double layer, induced by sodium sulphate, reduced the suction and deteriorated the microstructural characteristics, causing a degradation of the macroscale mechanical properties. Under sodium hydroxide conditions, a distinct transformation from granular structures to an agglomerated structure was attributed to the formation of sodium silicate, and the surface-surface connections were formed at the same time, which also indicated an enhancement of the microstructural characteristics. The enhanced microstructural characteristics contributed to the improvement in the macroscale mechanical properties. The findings of this study provide some design guideposts for preventing and mitigating the degradation of subgrade when exposed to saline environments.
PDF
