Search

Hydrogen sulfide (H 2 S) is a novel gaseous signaling molecule in response to adversity stress. Melatonin (MT) is a multifunctional molecule that plays an important role in regulating plant stress resistance. However, the interactions between H 2 S and MT are still unknown. Therefore, the role of H 2 S in MT-induced salt tolerance was elucidated in this study by measuring the antioxidant defense system and photosynthetic characteristics of cucumber. In addition, the crosstalk among H 2 S, NO, and mitogen-activated protein kinase (MAPK) was investigated. Results showed that MT induced the production of H 2 S by significantly increasing the activity of L-/D-cysteine desulfhydrase, thereby regulating photosynthetic efficiency, antioxidant enzyme activity, and antioxidant enzyme gene expression in cucumber, thus alleviating reactive oxygen species burst by salt stress. In this process, the H 2 S and NO induced by MT were inhibited by NO scavenger (cPTIO) and H 2 S scavenger (HT) but not affected by MAPK inhibitor (U0126). Intriguingly, the expression of MAPK3/4/6/9 was inhibited by HT and cPTIO. These results suggested that H 2 S may act as downstream of MT, interact with NO and MAPK cascades, and jointly participate in the process of MT mitigating salt stress in cucumber. In addition, H 2 S and NO are upstream signaling molecules of the MAPK cascades. • Melatonin (MT) and salt stress induced hydrogen sulfide (H 2 S) production through activating L/DCD in cucumber. • MT-induced increase in PS II reaction center activity is regulated by H 2 S in cucumber under salt stress. • H 2 S, NO and MAPK cascades participate in MT regulated salt tolerance in cucumber. [ABSTRACT FROM AUTHOR]

SARS CoV 3CLpro is known to be a promising target for development of therapeutic agents against the severe acute respiratory syndrome (SARS). A quinolinone compound 1 was selected via virtual screening, and it was synthetized and tested for enzymatic inhibition in vitro. Compound 1 showed potent inhibitory activity (IC50=0.44 µmol/L) toward SARS CoV 3CLpro. Further work on a series of quinolinone derivatives resulted in the discovery of the most potent compound 23, inhibiting SARS CoV 3CLpro with an IC50 of 36.86 nmol/L. The structure-activity relationships were also discussed. [ABSTRACT FROM AUTHOR]

Strigolactone (SL) is a plant hormone that can improve plant stress resistance by regulating physiological processes and gene expression. GR24 is a synthetic strigolactone, which can also be used as a plant growth regulator. In this paper, the effects of exogenous GR24 on the growth and development of rape (Brassica rapa L.) under low temperature (4 °C) were studied. The results showed that low temperature (4 °C) inhibited the growth of rape seedlings, and exogenous GR24 significantly alleviated the effect of low temperature stress on rape seedlings. Compared with 4 °C treatment, GR24 + 4 °C treatment can increase the cell viability, soluble protein and proline content, enhance antioxidant enzyme activity, inhibit the production of reactive oxygen species (ROS), improve photosynthesis, and reduce the relative conductivity of rape seedlings. Further research shows that H 2 O 2 plays a central role in improving the cold resistance of rape seedlings by GR24. qRT-PCR results indicated that GR24 significantly increased the expression of genes. Mainly includes antioxidant enzyme genes, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase genes, mitogen-activated protein kinase (MAPK) genes and cold-regulated genes. These results indicate that GR24 improves the cold tolerance of plants by regulating the expression of related genes. RNA-seq analysis revealed that there were 152 differentially expressed genes (DGEs) in T (4 °C)_vs_ST (GR24 + 4 °C), including 100 up-regulated genes and 52 down-regulated genes. These DEGs play an important role in carbon metabolism pathway, oxidative phosphorylation pathway, antioxidant activity and photosynthesis pathways. We selected 11 differentially expressed genes for qRT-PCR verification, and the verification results were consistent with RNA-seq results. • Strigolactone effectively alleviate the damage of low temperature stress to rape seedlings (Brassica rapa L.). • Strigolactone improves the cold tolerance of rape, which is regulated by the upstream signal molecule H 2 O 2. • Critical differentially expressed genes (DGEs) in the process of strigolactone alleviating the cold resistance of rape seedlings were identified by RNA-seq. [ABSTRACT FROM AUTHOR]

SARS CoV 3CL pro is known to be a promising target for development of therapeutic agents against the severe acute respiratory syndrome (SARS). A quinolinone compound 1 was selected via virtual screening, and it was synthetized and tested for enzymatic inhibition in vitro . Compound 1 showed potent inhibitory activity (IC 50 =0.44 µmol/L) toward SARS CoV 3CL pro . Further work on a series of quinolinone derivatives resulted in the discovery of the most potent compound 23 , inhibiting SARS CoV 3CL pro with an IC 50 of 36.86 nmol/L. The structure-activity relationships were also discussed., (Copyright © 2013 SIOC, CAS, Shanghai & WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)