The unprecedented early spring frost that appears as a cold stress adversely affects growth and productivity in tea (
L.); therefore, it is indispensable to develop approaches to improve the cold ...tolerance of tea. Here, we investigated the effect of pretreatment with exogenous melatonin on the net photosynthetic rate, the maximum photochemical efficiency of PSII, chlorophyll content, lipid peroxidation, reactive oxygen species (ROS) accumulation, antioxidant potential, and redox homeostasis in leaves of tea plants following cold stress. Our results revealed that cold treatment induced oxidative stress by increasing ROS accumulation, which in turn affected the photosynthetic process in tea leaves. However, treatment with melatonin mitigated cold-induced reductions in photosynthetic capacity by reducing oxidative stress through enhanced antioxidant potential and redox homeostasis. This study provides strong evidence that melatonin could alleviate cold-induced adverse effects in tea plants.
Rising CO
concentration, a driving force of climate change, is impacting global food security by affecting plant physiology. Nevertheless, the effects of elevated CO
on primary and secondary ...metabolism in tea plants (Camellia sinensis L.) still remain largely unknown. Here we showed that exposure of tea plants to elevated CO
(800 µmol mol
for 24 d) remarkably improved both photosynthesis and respiration in tea leaves. Furthermore, elevated CO
increased the concentrations of soluble sugar, starch and total carbon, but decreased the total nitrogen concentration, resulting in an increased carbon to nitrogen ratio in tea leaves. Among the tea quality parameters, tea polyphenol, free amino acid and theanine concentrations increased, while the caffeine concentration decreased after CO
enrichment. The concentrations of individual catechins were altered differentially resulting in an increased total catechins concentration under elevated CO
condition. Real-time qPCR analysis revealed that the expression levels of catechins and theanine biosynthetic genes were up-regulated, while that of caffeine synthetic genes were down-regulated in tea leaves when grown under elevated CO
condition. These results unveiled profound effects of CO
enrichment on photosynthesis and respiration in tea plants, which eventually modulated the biosynthesis of key secondary metabolites towards production of a quality green tea.
Pre‐eclampsia is a common complication during pregnancy; however, the underlying mechanisms of the crosstalk between low‐density lipoprotein receptor‐related protein 6 (LRP6) and autophagy in ...trophoblast cells are still not fully explored. Messenger RNA (mRNA) and protein levels of LRP6, beclin 1, Unc‐51‐like autophagy activating kinase 1 (ULK1), p62, vimentin, matrix metallopeptidase‐9 (MMP‐9), β‐catenin, c‐Myc, and Rab7, as well as the ratio of LC3‐II/LC3‐I, were analysed by quantitative real‐time polymerase chain reaction or Western blot analysis, respectively. An MTT assay was used to measure cell growth, and transwell and wound healing assays were carried out to evaluate the invasion and migration abilities of the trophoblasts used. An immunofluorescence assay was used to measure LC3. The mRFP‐GFP‐LC3 tandem fluorescence assay was applied to detect autophagic flow. LRP6 overexpression was achieved by constructing pcDNA3.1‐LRP6 vectors. LRP6 was expressed at low levels in HTR‐8/SVneo cells under hypoxia/reoxygenation (H/R) conditions. H/R inhibited the activation of autophagy. LRP6 overexpression promoted cell proliferation and activated autophagy, which led to the upregulation of beclin 1 and ULK1, as well as the ratio of LC3‐II/LC3‐I and the downregulation of p62. Furthermore, LRP6 overexpression elevated the migration and invasion abilities of the indicated cells and increased vimentin and MMP‐9 expression levels. Furthermore, LRP6 upregulated Rab7 and activated autophagy through the Wnt/β‐catenin pathway. The late autophagy inhibitor bafilomycin A1 (Baf‐A1) and the Wnt/β‐catenin pathway inhibitor PKF115‐584 reversed the effects of LRP6 on trophoblast autophagy, migration and invasion. LRP6 promotes Rab7‐mediated autophagy by activating the Wnt/β‐catenin pathway, which leads to increasing migration and invasion of trophoblast cells. Our study paves a new avenue for clinical treatment, and LRP6 may serve as an essential target in pre‐eclampsia.
low‐density lipoprotein receptor‐related protein 6 (LRP6) was lowly expressed in trophoblast cells under hypoxia/reoxygenation (H/R) treatment. LRP6 overexpression enhanced the autophagy flux to strengthen the functions of trophoblast cells. LRP6 overexpression induced autophagy to promote proliferation, migration and invasion of trophoblast cells.
Carbon-coated metal chalcogenide composites have been demonstrated as one type of promising anode material for sodium-ion batteries (SIBs). However, combining carbon materials with micronanoparticles ...of metal chalcogenide always involve complicated processes, such as polymer coating, carbonization, and sulfidation/selenization. To address this issue, herein, we reported a series of carbon-coated FexSey@CN (FexSey = FeSe2, Fe3Se4, Fe7Se8) composites prepared via the thermodynamic transformation of a crystalline organic hybrid iron selenide Fe(phen)2(Se4) (phen = 1,10-phenanthroline). By pyrolyzing the bulk crystals of Fe(phen)2(Se4) at different temperatures, FexSey microrods were formed in situ, where the nitrogen-doped carbon layers were coated on the surface of the microrods. Moreover, all the as-prepared FexSey@CN composites exhibited excellent sodium-ion storage capabilities as anode materials in SIBs. This work proves that crystalline organic hybrid metal chalcogenides can be used as a novel material system for the in situ formation of carbon-coated metal chalcogenide composites, which could have great potential in the application of electrochemical energy storage.
H/D exchange at formyl groups represents the straightforward approach to C-1 deuterated aldehydes. This transformation has been recently realized by transition metal and NHC carbene catalysis. ...Mechanistically, all of these processes involve an ionic pathway. Herein, we report a distinct photoredox catalytic, visible light mediated neutral radical approach. Selective control of highly reactive acyl radical in the energy barrier surmountable, reversible reaction enables driving the formation of deuterated products when an excess of D2O is employed. The power of the H/D exchange process has been demonstrated for not only aromatic aldehydes but also aliphatic substrates, which have been difficult in transitional metal catalyzed H/D exchange reactions, and for selective late-stage deuterium incorporation into complex structures with uniformly high deuteration level (>90%).
SUMMARY
Many rice microRNAs have been identified as fine‐tuning factors in the regulation of agronomic traits and immunity. Among them, Osa‐miR535 targets SQUAMOSA promoter binding protein‐like 14 ...(OsSPL14) to positively regulate tillers but negatively regulate yield and immunity. Here, we uncovered that Osa‐miR535 targets another SPL gene, OsSPL4, to suppress rice immunity against Magnaporthe oryzae. Overexpression of Osa‐miR535 significantly decreased the accumulation of the fusion protein SPL4TBS‐YFP that contains the target site of Osa‐miR535 in OsSPL4. Consistently, Osa‐miR535 mediated the cleavage of OsSPL4 mRNA between the 10th and 11th base pair of the predicted binding site at the 3′ untranslated region. Transgenic rice lines overexpressing OsSPL4 (OXSPL4) displayed enhanced blast disease resistance accompanied by enhanced immune responses, including increased expression of defense‐relative genes and up‐accumulated H2O2. By contrast, the knockout mutant osspl4 exhibited susceptibility. Moreover, OsSPL4 binds to the promoter of GH3.2, an indole‐3‐acetic acid‐amido synthetase, and promotes its expression. Together, these data indicate that Os‐miR535 targets OsSPL4 and OsSPL4‐GH3.2, which may parallel the OsSPL14‐WRKY45 module in rice blast disease resistance.
Significance Statement
Previously, Osa‐miR535 was identified to target SPL14 to regulate rice immunity. Here, we identified that Osa‐miR535 targets another SPL family gene, OsSPL4. OsSPL4 binds the promoter of GH3.2 to positively regulate rice immunity, which functionally parallels with OsSPL14‐WRKY45 module downstream of Osa‐miR535.
An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters ...serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C–C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.
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•Formic acid selectively inhibited the activity of nitrite oxidizing bacteria (NOB).•The inhibition of nxrB transcription in NOB resulted in high nitrite accumulation.•Long-term ...stable nitritation was achieved by sustained suppression of NOB.•Formic acid acclimation promoted the aerobic denitrification of activated sludge.
The feasibility of achieving stable nitritation inoculating with activated sludge by adding formic acid was studied in this work. Short-term batch effects of formic acid on nitrification showed that the nitrite accumulation ratio (NAR) significantly increased from 0.3% to 83.7% with an increase of formic acid concentration from 0 to 50 mM at an initial ammonia concentration of 75 mg·L−1, which was demonstrated to be due to the inhibition of nxrB transcription in nitrite oxidizing bacteria (NOB). The long-term effects of formic acid at 30 mM were constantly monitored in an aerobic sequencing batch reactor. During 27 days of operation, the NAR was rapidly raised and maintained approximately 90%. What’s more, in the following 52 days without addition of formic acid, the NAR was kept above 91.3%. The sustained suppression of NOB genus Nitrospira coupling nxrB inhibition was the main reason to maintain stable nitritation. These results supported the feasibility of formic acid as an efficient nitritation regulator, thus providing a new approach for the development of the BNR process via nitrite pathway.
The development of male and female gametophytes is a pre-requisite for successful reproduction of angiosperms. Factors mediating vesicular trafficking are among the key regulators controlling ...gametophytic development. Fusion between vesicles and target membranes requires the assembly of a fusogenic soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) complex, whose disassembly in turn ensures the recycle of individual SNARE components. The disassembly of post-fusion SNARE complexes is controlled by the AAA+ ATPase N-ethylmaleimide-sensitive factor (Sec18/NSF) and soluble NSF attachment protein (Sec17/α-SNAP) in yeast and metazoans. Although non-canonical α-SNAPs have been functionally characterized in soybeans, the biological function of canonical α-SNAPs has yet to be demonstrated in plants. We report here that the canonical α-SNAP in Arabidopsis is essential for male and female gametophytic development. Functional loss of the canonical α-SNAP in Arabidopsis results in gametophytic lethality by arresting the first mitosis during gametogenesis. We further show that Arabidopsis α-SNAP encodes two isoforms due to alternative splicing. Both isoforms interact with the Arabidopsis homolog of NSF whereas have distinct subcellular localizations. The presence of similar alternative splicing of human α-SNAP indicates that functional distinction of two α-SNAP isoforms is evolutionarily conserved.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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