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The action of abscisic acid (ABA) is closely related to its level in plant tissues. Uridine diphosphate-glycosyltransferase71c5 (UGT71C5) was characterized as a major UGT enzyme to catalyze the formation of the ABA-glucose ester (ABA-GE), a reversible inactive form of free ABA in Arabidopsis thaliana (thale cress). UGTs function in a mode where the catalytic base deprotonates an acceptor to allow a nucleophilic attack at the anomeric center of the donor, achieving the transfer of a glucose moiety. The proteomic data revealed that UGT71C5 can be persulfidated. Herein, an experimental method was employed to detect the persulfidation site of UGT71C5, and the computational methods were further used to identify the yet unknown molecular basis of ABA glycosylation as well as the regulatory role of persulfidation in this process. Our results suggest that the linker and the U-shaped loop are regulatory structural elements: the linker is associated with the binding of uridine diphosphate glucose (UPG) and the U-shaped loop is involved in binding both UPG and ABA.It was also found that it is through tuning the dynamics of the U-shaped loop that is accompanied by the movement of tyrosine (Y388) that the persulfidation of cysteine (C311) leads to the catalytic residue histidine (H16) being in place, preparing for the deprotonation of ABA, and then reorientates UPG and deprotonated ABA closer to the 'Michaelis' complex, facilitating the transfer of a glucose moiety. Ultimately, the persulfidation of UGT71C5 is in favor of ABA glycosylation. Our results provide insights into the molecular details of UGT71C5 recognizing substrates and insights concerning persulfidation as a possible mechanism for hydrogen sulfide (H2S) to modulate the content of ABA, which helps us understand how modulating ABA level strengthens plant tolerance. [ABSTRACT FROM AUTHOR]

In this paper, we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity, namely f(Q) theory, and investigate the tensor perturbations therein. As is well-known, the tensor perturbations generated in the very early Universe (inflation and pre-inflation regions) can account for the primordial gravitational waves (PGWs) that are to be detected by the next generation of GW experiments. We discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation variable. The general form of the tensor power spectrum is obtained both for large as well as small scale modes. As a result, we show both kinds of modes (short or long wavelength modes), and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves' amplitude in the background of the f(Q) bounce-inflation scenario. Moreover, we study the LQC-like scenario as a specific case of our model, in which, the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales. [ABSTRACT FROM AUTHOR]

Post-fermented tea (PFT) is one of the most commonly consumed beverages worldwide. Rapid microbial growth and significant changes in the microbial composition of PFT during processing and storage pose a potential risk of contamination with mycotoxins such as zearalenone (ZEN). Screening for ZEN contamination in a simple, rapid, and inexpensive manner is required to ensure that PFT is safe for consumption. To monitor ZEN in PFT, ZEN was conjugated with bovine serum albumin to prepare egg yolk immunoglobulins (IgY). A specific indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on IgY was developed and validated. ZEN was extracted with acetonitrile and water (50:50, v/v) containing 5% acetic acid and purified using a mixture of primary and secondary amines and graphitized carbon black to remove matrix interference from the PFT samples. Under optimal conditions, the linear range of this assay was 13.8−508.9 ng mL−1, the limit of detection was 9.3 ng mL−1, and the half-maximal inhibitory concentration was 83.8 ng mL−1. Cross-reactivity was negligible, and the assay was specific for ZEN-related molecules. The recovery rate of ZEN in the control blanks of PFT samples spiked with a defined concentration of ZEN of 89.5% to 98.0%. The recovery and accuracy of the method were qualified for PFT matrices. No significant differences were evident between the results of the actual PFT samples analyzed by high-performance liquid chromatography and ic-ELISA. The collective data indicate that the developed ic-ELISA can be used for the rapid and simple detection of ZEN in PFT products. [ABSTRACT FROM AUTHOR]

Post-fermented tea (PFT), a commonly consumed beverage worldwide, is characterized by the rapid growth of its microbial groups and the substantial changes they undergo. Consequently, PFT may contain mycotoxins such as B-type fumonisins (FBs). This study aimed to assess the intake of FBs through the consumption of PFT among consumers in Guangxi, China. A novel quantitative method using high-performance liquid chromatography-mass spectrometry was used to determine the FB concentration in PFT products. Additionally, a PFT consumption survey was conducted using a face-to-face questionnaire, recording their body weight and PFT consumption patterns based on a three-day dietary recall method. Finally, hazard index was calculated to estimate the health risk of FBs from the consumption of PFT products in Guangxi. The results revealed that the occurrence of FBs in PFT was 20% (24/120), with a concentration ranging from 2.14 to 18.28 μg/kg. The results of the survey showed that the average daily consumption of PFT by consumers was 9.19 ± 11.14 g. The deterministic risk assessment revealed that only 0.026% of the provisional maximum tolerable daily intake of FBs was consumed through PFT, indicating that FB contamination in PFT is not a public health risk. [ABSTRACT FROM AUTHOR]

Civic activism is increasingly popular for authoritarian regimes to ensure local compliance and improve local governance, but it also places pressure on local officials. How do local officials respond to such pressures? With a unique dataset of city‐level environmental investigations and public interest litigation in China, we conduct a generalized difference‐in‐difference analysis and find that public interest litigation, a new legal channel for social actors to monitor environmental governance, can significantly reduce information disclosure related to investigations. Furthermore, it changes the focus of investigations: the number of low‐profile investigations is increased, while the number of high‐profile cases is decreased. This finding reveals how local officials avoid public monitoring by reducing information disclosure but maintaining a certain level of enforcement, which implies that the effect of civic engagement on the accountability of local governments in authoritarian regimes is dynamic with the coevolution of strategies of local officials and civil societies. [ABSTRACT FROM AUTHOR]

Growth-regulating factor (GRF) exerts important functions related to plant development and stress response. However, in Medicago truncatula, the GRF family has not been comprehensively analyzed at the genome level. This study identified eight MtGRF genes (containing both QLQ and WRC domains) in the M. truncatula genome, and no duplicate events occurred between these genes. Gene expression analysis showed that MtGRFs exhibited the highest expression in shoot apical meristems (SAM) followed by seeds, flowers, roots, etc. MtGRF2-6 and MtGRF8 were induced by GA, IAA, and ABA, and MtGRF2 and MtGRF5 also responded to MeJA. Additionally, eight, five, and seven MtGRF genes were differentially expressed under drought, salt, and cold stress, respectively. Five MtGRF genes (MtGRF1, 2, 6, 7, and 8) responded to all three types of stresses, especially MtGRF8, the expression of which was inhibited under drought, salt, and cold stress. These results indicated that MtGRF8 may be a negative regulator of the stress response. Degradome analysis showed that all eight MtGRFs were the target genes of Mt-miR396, and MtGRF4 may be jointly regulated by Mt-miR396 and other microRNAs. These results will contribute to the understanding of the GRF family in M. truncatula. [ABSTRACT FROM AUTHOR]

Stochastic gravitational wave background (SGWB) is a promising tool to probe the very early universe where the standard model of particle physics and cosmology are connected closely. As a possible component of SGWB, gravitational waves (GW) from bubble collisions during the first order cosmological phase transitions deserve comprehensive analyses. In 2017, Ryusuke Jinno and Masahiro Takimoto proposed an elegant analysis approach to derive the analytical expressions of energy spectra of GW from bubble collisions in Minkowski spacetime avoiding large-scale numerical simulations for the first time [26]. However, they neglect the expansion of the universe and regard the duration of phase transitions as infinity in their derivation which could deviate their estimations from true values. For these two reasons, we give a new expression of GW spectra by adopting their method, switching spacetime background to FLRW spacetime, and considering a finite duration of phase transitions. By denoting σ as the fraction of the speed of phase transitions to the expansion speed of the universe, we find when σ is around O (10), the maxima of estimated GW energy spectra drop by around 1 order of magnitude than the results given by their previous work. Even when σ = 100, the maximum of GW energy spectrum is only 65% of their previous estimation. Such a significant decrease may bring about new challenges for the detectability of GW from bubble collisions. Luckily, by comparing new spectra with PLI (power-law integrated) sensitivity curves of GW detectors, we find that the detection prospect for GW from bubble collisions is still promising for DECIGO, BBO, LISA, and TianQin in the foreseeable future. [ABSTRACT FROM AUTHOR]

The recent observations from CMB have imposed a very stringent upper-limit on the tensor/scalar ratio r of inflation models, r < 0.064 , which indicates that the primordial gravitational waves (PGW), even though possible to be detected, should have a power spectrum of a tiny amplitude. However, current experiments on PGW is ambitious to detect such a signal by improving the accuracy to an even higher level. Whatever their results are, it will give us much information about the early Universe, not only from the astrophysical side but also from the theoretical side, such as model building for the early Universe. In this paper, we are interested in analyzing what kind of inflation models can be favored by future observations, starting with a kind of general action offered by the effective field theory (EFT) approach. We show a general form of r that can be reduced to various models, and more importantly, we show how the accuracy of future observations can put constraints on model parameters by plotting the contours in their parameter spaces. [ABSTRACT FROM AUTHOR]

We study the chameleon field dark matter, dubbed scalaron, in F (R) gravity in the Big Bang Nucleosynthesis (BBN) epoch. With an R2-correction term required to solve the singularity problem for F (R) gravity, we first find that the scalaron dynamics is governed by the R2 term and the chameleon mechanism in the early universe, which makes the scalaron physics model-independent regarding the low-energy scale modification. In viable F (R) dark energy models including the R2 correction, our analysis suggests the scalaron universally evolves in a way with a bouncing oscillation irrespective of the low-energy modification for the late-time cosmic acceleration. Consequently, we find a universal bound on the scalaron mass in the BBN epoch, to be reflected on the constraint for the coupling strength of the R2 term, which turns out to be more stringent than the one coming from the fifth force experiments. It is then shown that the scalaron naturally develops a small enough fluctuation in the BBN epoch, hence can avoid the current BBN constraint placed by the latest Planck 2018 data, and can also have a large enough sensitivity to be hunted by the BBN, with more accurate measurements for light element abundances as well as the baryon number density fraction. [ABSTRACT FROM AUTHOR]

In this paper, we continue our study of the curvaton model with nonminimal derivative coupling (NDC) to Einstein gravity proposed in our previous work (Feng in Phys Lett B 729:99, 2014; Feng and Qiu in Phys Rev D 90(12):123508, 2014), focusing on the reheating mechanism. We found that according to whether the curvaton has or has not dominated the background after the end of inflation, it will have two different behaviors of evolution, which should be the general property of the curvaton with nonminimal couplings. This will cause two different parts of reheating, which goes on via the parametric resonance process. The reheating temperature is estimated for both cases in which reheating completes before and after curvaton domination, and the constraints are quite loose compared to that of overproduction of gravitinos. Finally we investigated the evolution of curvature perturbation during reheating. We have shown both analytically and numerically that the curvature perturbation will not blow up during the resonance process. [ABSTRACT FROM AUTHOR]

Based on the effective field theory (EFT) of cosmological perturbations, we explicitly clarify the pathology in nonsingular cubic Galileon models and show how to cure it in EFT with new insights into this issue. With the least set of EFT operators that are capable to avoid instabilities in nonsingular cosmologies, we construct a nonsingular model dubbed the Genesis-inflation model, in which a slowly expanding phase (namely, Genesis) with increasing energy density is followed by slow-roll inflation. The spectrum of the primordial perturbation may be simulated numerically, which shows itself a large-scale cutoff, as the large-scale anomalies in CMB might be a hint for. [ABSTRACT FROM AUTHOR]

Recently BICEP2 collaboration has announced the detection of the primordial gravitational waves at high confidence level. In light of the results of B-modes power spectrum from BICEP2 and using the based ΛCDM, a constraint on the tensor-to-scalar ratio r = 0.20 (68% C.L.) can be obtained, however, this result is in apparent tension with the limit on standard inflation models from the recent PLANCK measurement, r < 0.11 (95% C.L.). Herein we review the recent progress on the cosmological studies after BICEP2 and discuss on different ways of reconciling the tension between PLANCK and BICEP2 data. We will discuss possible modifications on the standard cosmological model, such as including the running of scalar spectral index or other cosmological parameters correlated with inflationary cosmological parameters, or tilting the primordial power spectrum at large scales by introducing a cut off which can be predicted by bouncing cosmology. We will also comment on another possibility of generating extra B-modes of CMB polarization, namely by a non-zero polarization rotation angle during its transferring from the last scattering surface. [ABSTRACT FROM AUTHOR]

Quintom models, with its Equation of State being able to cross the cosmological constant boundary w = -1, turns out to be attractive for phenomenological study. It can not only be applicable for dark energy model for current universe, but also lead to a bounce scenario in the early universe. [ABSTRACT FROM AUTHOR]

In this paper, we study the possibility of model building of cyclic universe with Quintom matter in the framework of Loop Quantum Cosmology. After a general demonstration, we provide two examples, one with double-fluid and another double-scalar field, to show how such a scenario is obtained. Analytical and numerical calculations are both presented in the paper. [ABSTRACT FROM AUTHOR]

Null Energy Condition (NEC) requires the equation of state (EoS) of the universe wu satisfy wu ≥ -1, which implies, for instance in a universe with matter and dark energy dominating wu = wmΩm + wdeΩde = wdeΩde ≥ -1. In this paper we study constraints on the dark energy models from the requirement of the NEC. We will show that with Ωde ~ 0.7, wde < -1 at present epoch is possible. However, NEC excludes the possibility of wde < -1 forever as happened in the Phantom model, but if wde < -1 stays for a short period of time as predicted in the Quintom theory, NEC can be satisfied. We take three examples of Quintom models of dark energy, namely the phenomenological EoS, the two-scalar-field model and the single scalar model with a modified Dirac–Born–Infeld (DBI) Lagrangian to show how this happens. [ABSTRACT FROM AUTHOR]

In this work, we revisit the perturbations that are generated in the bounce inflation scenario constructed within the framework of f(T) theory. It has been well known that pure f(T) theory cannot give rise to bounce inflation behavior, so aside from the gravity part, we also employ a canonical scalar field for minimal extension. We calculate the perturbations in f(T) theory using the well-established ADM formalism, and find various conditions to avoid their pathologies. We find that it is indeed very difficult to obtain a healthy model without those pathologies, however, one may find a way out if a potential requirement, say, to keep every function continuous, is abandoned. [ABSTRACT FROM AUTHOR]

The aim of this paper is to probe the features of the bouncing cosmology with the current observational data. Basing on bounce inflation model, with high derivative term, we propose a general parametrization of primordial power spectrum which includes the typical bouncing parameters, such as bouncing time-scale, and energy scale. By applying Markov Chain Monto Carlo analysis with current data combination of Planck 2015, BAO and JLA, we report the posterior probability distributions of the parameters. We find that, bouncing models can well explain CMB observations, especially the deficit and oscillation on large scale in TT power spectrum. [ABSTRACT FROM AUTHOR]