Halophytic
Hordeum brevisubulatum
is a perennial grass which has evolved many distinctive salt-adaptive mechanisms. Our previous studies indicated it could thrive under salt stress through ...maintaining better K
+
and Na
+
homeostasis. Stress-responsive HbCIPK2 can phosphorylate K
+
channel HbVGKC1 and Na
+
transporter HbSOS1L to prevent Na
+
accumulation and K
+
reduction, hence pathway was not detected in glycophytic plants. In this study, we cloned the inducible promoter of
HbCIPK2
by genome-walking, and identified a novel transcriptional regulator HbERF6 through yeast one-hybrid screening. HbERF6 functioned as a transcription factor which can bind to the GCC-box of the
HbCIPK2
promoter to activate its expression.
HbERF6
transgenic lines in
Arabidopsis
improved salt tolerance compared with wild type, and especially induced
AtCIPK24
(
SOS2
) expression, resulting in K
+
/Na
+
homeostasis to enhance salt tolerance. All the results confirmed the inducible function of HbERF6 for CIPK genes during salt tolerance. This regulatory network that integrates transcriptional regulation and post-translation modification will unravel a novel salt stress-responsive mechanism, highlighting the value and utilization of the halophytic resource.
Two kinds of naphthalimide derivatives were synthesized and evaluated for in vitro their anti-hepatocellular carcinoma properties. Compound
with a fused thiazole fragment to naphthalimide skeleton ...inhibited cell migration of SMMC-7721 and HepG2, and further in vivo trials with two animal models confirmed that compound
moderately inhibited primary H22 tumor growth (52.6%) and potently interrupted lung metastasis (75.7%) without obvious systemic toxicity at the therapeutic dose. Mechanistic research revealed that compound
inhibited cancerous liver cell growth mostly by inducing G2/M phase arrest. Western blotting experiments corroborated that
could up-regulate the cell cycle related protein expression of cyclin B1, CDK1 and p21, and inhibit cell migration by elevating the E-cadherin and attenuating integrin α6 expression. Our study showed that compound
is a valuable lead compound worthy of further investigation.
We propose a novel wideband chaos generation scheme by using an external-cavity semiconductor laser (ECSL) subject to optical-electronic hybrid feedback. In this scheme, the output of ECSL is ...photo-detected and used to modulate the output of a continuous wave laser by an electro-optical phase modulator, the constant-amplitude self-phase-modulated light is then injected back into the ECSL. The experimental results indicate that, compared with the chaos generation with conventional optical feedback (COF), significant bandwidth enhancement is achieved in the proposed scheme. The effective bandwidth of generated chaos is increased from a few GHz to over 20 GHz, and moreover, the spectrum flatness and the complexity of generated chaos are also considerably improved. Furthermore, we propose a wideband chaos synchronization system based on the proposed chaos generation scheme. It is experimentally demonstrated that high-quality synchronization between two wideband chaos signals with an effective bandwidth greater than 20 GHz is achieved. This work simultaneously achieves the generation and the synchronization of wideband chaos, which shows valuable potential in chaos-based secure communication, such as enhancing the transmission capacity and improving the security.
Ryanodine receptors （RyRs） are a class of giant ion channels with molecular mass over 2.2 mega-Daltons. These channels mediate calcium signaling in a variety of cells. Since more than 80% of the RyR ...protein is folded into the cytoplasmic assembly and the remaining residues form the transmembrane domain, it has been hypothesized that the activation and regulation of RyR channels occur through an as yet uncharacterized long-range allosteric mechanism. Here we report the characterization of a Ca^2＋-activated open-state RyR1 structure by cryo-electron microscopy. The structure has an overall resolution of 4.9 A° and a resolution of 4.2A° for the core region. In comparison with the previously determined apo/closed-state structure, we observed long-range allosteric gating of the channel upon Ca^2＋ activation. In-depth structural analyses elucidated a novel channel-gating mechanism and a novel ion selectivity mechanism of RyR1. Our work not only provides structural insights into the molecular mechanisms of channel gating and regulation of RyRs, but also sheds light on structural basis for channel-gating and ion selectivity mechanisms for the six-transmembrane-helix cation channel family.
Suppressing nucleation over large areas
Although formamidinium-based lead iodide (PbI
2
) perovskites have a favorable bandgap and good thermal stability, the difficulty in controlling nucleation ...makes it difficult to grow high-quality, large-area films compared with methylammonium counterparts. Bu
et al.
show that adding
N
-methyl-2-pyrrolidone to the perovskite precursors forms an adduct with PbI
2
that promotes the formation of the desired black α-phase at room temperature. The addition of potassium hexafluorophosphate eliminated hysteresis by passivating interfacial defects and promoted long-term thermal stability at 85°C in unencapsulated devices. Large-area modules (17 square centimeters) achieved power conversion efficiencies of 20.4%.
Science
, abh1035, this issue p.
1327
Added
N
-methylpyrrolidone inhibits nucleation and enables growth of large-area α-phase formamidinium-based perovskite films.
Upscaling efficient and stable perovskite layers is one of the most challenging issues in the commercialization of perovskite solar cells. Here, a lead halide–templated crystallization strategy is developed for printing formamidinium (FA)–cesium (Cs) lead triiodide perovskite films. High-quality large-area films are achieved through controlled nucleation and growth of a lead halide•
N
-methyl-2-pyrrolidone adduct that can react in situ with embedded FAI/CsI to directly form α-phase perovskite, sidestepping the phase transformation from δ-phase. A nonencapsulated device with 23% efficiency and excellent long-term thermal stability (at 85°C) in ambient air (~80% efficiency retention after 500 hours) is achieved with further addition of potassium hexafluorophosphate. The slot die–printed minimodules achieve champion efficiencies of 20.42% (certified efficiency 19.3%) and 19.54% with an active area of 17.1 and 65.0 square centimeters, respectively.
Autophagy increases the lifespan of model organisms; however, its role in promoting mammalian longevity is less well-established
. Here we report lifespan and healthspan extension in a mouse model ...with increased basal autophagy. To determine the effects of constitutively increased autophagy on mammalian health, we generated targeted mutant mice with a Phe121Ala mutation in beclin 1 (Becn1
) that decreases its interaction with the negative regulator BCL2. We demonstrate that the interaction between beclin 1 and BCL2 is disrupted in several tissues in Becn1
knock-in mice in association with higher levels of basal autophagic flux. Compared to wild-type littermates, the lifespan of both male and female knock-in mice is significantly increased. The healthspan of the knock-in mice also improves, as phenotypes such as age-related renal and cardiac pathological changes and spontaneous tumorigenesis are diminished. Moreover, mice deficient in the anti-ageing protein klotho
have increased beclin 1 and BCL2 interaction and decreased autophagy. These phenotypes, along with premature lethality and infertility, are rescued by the beclin 1(F121A) mutation. Together, our data demonstrate that disruption of the beclin 1-BCL2 complex is an effective mechanism to increase autophagy, prevent premature ageing, improve healthspan and promote longevity in mammals.
Polyethylene terephthalate (PET) hydrolase from Ideonella sakaiensis (IsPETase) can be used to degrade PET. In order to use IsPETase in industry, we studied the enzymatic activity of IsPETase in ...different conditions containing environmental and physicochemical factors commonly found in nature. We observed that salts and glycerol enhanced the enzymatic activity, while detergents and organic solvents reduced the enzymatic activity. IsPETase hydrolyzed p-nitrophenyl (p-NP) esters instead of naphthyl esters. To make IsPETase an enzyme capable of hydrolyzing naphthyl esters, site-directed mutagenesis was carried out based on the structural information provided by the crystal structure. We found that the IsPETaseS93M, IsPETaseW159F, and IsPETaseN241F mutants can hydrolyze naphthyl esters. IsPETase engineering can direct researchers to use this α/β-hydrolase protein scaffold to design enzymes that can hydrolyze a variety of polyesters.
•Salts and moderate concentrations of glycerol enhance the enzymatic activity of IsPETase.•Detergents and organic solvents reduce the enzymatic activity of IsPETase.•Substrate specificity of IsPETase is determined by hydrophobic and steric effects.•Mutations of critical residues around the catalytic center transform substrate specificity.
PDF
