As genomes of many plant species have been sequenced, demand for functional genomics has dramatically accelerated the improvement of other omics including metabolomics. Despite a large amount of ...metabolites still remaining to be identified, metabolomics has contributed significantly not only to the understanding of plant physiology and biology from the view of small chemical molecules that reflect the end point of biological activities, but also in past decades to the attempts to improve plant behavior under both normal and stressed conditions. Hereby, we summarize the current knowledge on the genetic and biochemical mechanisms underlying plant growth, development, and stress responses, focusing further on the contributions of metabolomics to practical applications in crop quality improvement and food safety assessment, as well as plant metabolic engineering. We also highlight the current challenges and future perspectives in this inspiring area, with the aim to stimulate further studies leading to better crop improvement of yield and quality.
The pollen wall is a specialized extracellular cell wall matrix that surrounds male gametophytes and plays an essential role in plant reproduction. Uncovering the mechanisms that control the ...synthesis and polymerization of the precursors of pollen wall components has been a major research focus in plant biology. We review current knowledge on the genetic and biochemical mechanisms underlying pollen wall development in eudicot model Arabidopsis thaliana and monocot model rice (Oryza sativa), focusing on the genes involved in the biosynthesis, transport, and assembly of various precursors of pollen wall components. The conserved and divergent aspects of the genes involved as well as their regulation are addressed. Current challenges and future perspectives are also highlighted.
Pollen wall development exhibits conserved and diversified features.
Genes associated with pollen wall development are coordinately regulated.
The synthesis of exine and anther cutin may share common pathways in rice.
Entanglement can exist not only in the microscopic system (e.g., atom, photon, and ion trap) but also in macroscopic systems. According to recent research, entanglement can be achieved and controlled ...in superconducting devices. The quantum dynamics and entanglement mechanism of the coupled superconducting phase qubit and a two-level system (TLS) were demonstrated when the bipartite system was under microwave driving. Besides, the results reveal that when the system was experiencing decoherence, entanglement (concurrence) of the coupled superconducting phase qubit and TLS would oscillate damply with microwave driving time, even exhibiting concurrence sudden death and revival. The coupling effect of the superconducting qubit and TLS system and the resonant microwave together help to achieve entanglement, while concurrence death and concurrence revival are dependent on the decoherence source and mechanism, for example, the resonant microwave driving time acting on the bipartite coupling system. Furthermore, the simulation results show the entanglement of the coupled qubit and TLS system also depends on the purity of the initial states of the system. The article carried out a numerical simulation on the entanglement of different initial states, and the results showed that the entanglement of the coupled system changes with different initial states. For different initial states, entanglement, sudden death, and rejuvenation are still visible.
Nanocrystal clear: Optical‐magnetic (OM) bifunctional NaGdF4:Nd3+,Yb3+,Er3+ nanocrystals were successfully synthesized that consist of luminescent Er3+ ions and a coordinating magnetic Gd3+ ion. The ...luminescence of NaGdF4:Nd3+,Yb3+,Er3+ nanocrystals was tuned by changing the applied magnetic field (see figure) both at room temperature and ultralow temperatures.
Abstract
This study presents a clock synchronization method based on quantum entanglement which is simple and reliable and more efficient. The clock synchronization method based on quantum ...entanglement scheme can greatly improve the accuracy and precision of measurement. More importantly, the proposed method avoids synchronization error caused by traditional method due to the asymmetry of two-way delay. The probability of measuring the quantum state oscillates in cosine or sine fashion with propagation delay. The final experimental and simulation results are basically consistent with the theoretical results. The clock synchronization method based on quantum entanglement scheme can greatly imrprove the accuracy and precision of measurement.
•The pier-column backfill mining (PCBM) technology was proposed.•The design method of the key technical parameters has been studied.•The proposed PCBM technology was tested in two panels of a Chinese ...coal mine.•Technical and economical comparisons between similar technologies were provided.
Finding an analytical solution to the Schrödinger equation with power function superposition potential is essential for the development of quantum theory. For example, the harmonic oscillator ...potential, Coulomb potential, and Klazer potential are all classed as power function superposition potentials. In this study, the general form of the power function superposition potential was used to decompose the second-order radial Schrödinger equation with this potential into the first-order Ricatti equation. Furthermore, two forms of the power function superposition potential are constructed with an exact analytical solution, and the exact bound-state energy level formula is obtained for these two potentials. Finally, the energy levels of some of the diatomic molecules were determined through calculation. And our results are actually consistent with those obtained by other methods.
High systemic estrogen levels contribute to breast cancer risk for postmenopausal women, whereas low levels contribute to osteoporosis risk. Except for obesity, determinants of non-ovarian systemic ...estrogen levels are undefined. We sought to identify members and functions of the intestinal microbial community associated with estrogen levels via enterohepatic recirculation.
Fifty-one epidemiologists at the National Institutes of Health, including 25 men, 7 postmenopausal women, and 19 premenopausal women, provided urine and aliquots of feces, using methods proven to yield accurate and reproducible results. Estradiol, estrone, 13 estrogen metabolites (EM), and their sum (total estrogens) were quantified in urine and feces by liquid chromatography/tandem mass spectrometry. In feces, β-glucuronidase and β-glucosidase activities were determined by realtime kinetics, and microbiome diversity and taxonomy were estimated by pyrosequencing 16S rRNA amplicons. Pearson correlations were computed for each loge estrogen level, loge enzymatic activity level, and microbiome alpha diversity estimate. For the 55 taxa with mean relative abundance of at least 0.1%, ordinal levels were created zero, low (below median of detected sequences), high and compared to loge estrogens, β-glucuronidase and β-glucosidase enzymatic activity levels by linear regression. Significance was based on two-sided tests with α=0.05.
In men and postmenopausal women, levels of total urinary estrogens (as well as most individual EM) were very strongly and directly associated with all measures of fecal microbiome richness and alpha diversity (R≥0.50, P≤0.003). These non-ovarian systemic estrogens also were strongly and significantly associated with fecal Clostridia taxa, including non-Clostridiales and three genera in the Ruminococcaceae family (R=0.57-0.70, P=0.03-0.002). Estrone, but not other EM, in urine correlated significantly with functional activity of fecal β-glucuronidase (R=0.36, P=0.04). In contrast, fecal β-glucuronidase correlated inversely with fecal total estrogens, both conjugated and deconjugated (R≤-0.47, P≤0.01). Premenopausal female estrogen levels, which were collected across menstrual cycles and thus highly variable, were completely unrelated to fecal microbiome and enzyme parameters (P≥0.6).
Intestinal microbial richness and functions, including but not limited to β-glucuronidase, influence levels of non-ovarian estrogens via enterohepatic circulation. Thus, the gut microbial community likely affects the risk for estrogen-related conditions in older adults. Understanding how Clostridia taxa relate to systemic estrogens may identify targets for interventions.
We tested the hypothesis that an altered community of gut microbes is associated with risk of colorectal cancer (CRC) in a study of 47 CRC case subjects and 94 control subjects. 16S rRNA genes in ...fecal bacterial DNA were amplified by universal primers, sequenced by 454 FLX technology, and aligned for taxonomic classification to microbial genomes using the QIIME pipeline. Taxonomic differences were confirmed with quantitative polymerase chain reaction and adjusted for false discovery rate. All statistical tests were two-sided. From 794217 16S rRNA gene sequences, we found that CRC case subjects had decreased overall microbial community diversity (P = .02). In taxonomy-based analyses, lower relative abundance of Clostridia (68.6% vs 77.8%) and increased carriage of Fusobacterium (multivariable odds ratio OR = 4.11; 95% confidence interval CI = 1.62 to 10.47) and Porphyromonas (OR = 5.17; 95% CI = 1.75 to 15.25) were found in case subjects compared with control subjects. Because of the potentially modifiable nature of the gut bacteria, our findings may have implications for CRC prevention.
PDF
