Evaluation of PEN2-ATP6AP1 axis as an antiparasitic target for metformin based on phylogeny analysis and molecular docking.

BACKGROUND: Metformin (Met), the first-line drug used in the treatment for type 2 diabetes mellitus, is effective against a variety of parasites. However, the molecular target of Met at clinical dose against various parasites remains unclear. Recently, low-dose Met (clinical dose) has been reported to directly bind PEN2 (presenilin enhancer protein 2) and initiate the lysosomal glucose-sensing pathway for AMPK activation via ATP6AP1 (V-type proton ATPase subunit S1), rather than perturbing AMP/ATP levels. METHODS: To explore the possibility of PEN2-ATP6AP1 axis as a drug target of Met for the treatment of parasitic diseases, we identified and characterized orthologs of PEN2 and ATP6AP1 genes in parasites, by constructing phylogenetic trees, analyzing protein sequences and predicting interactions between Met and parasite PEN2. RESULTS: The results showed that PEN2 and ATP6AP1 genes are only found together in a few of parasite species in the cestoda and nematoda groups. Indicated by molecular simulation, Met might function by interacting with PEN2 on V37/W38/E5 (Trichinella spiralis) with similar binding energy, and on F35/S39 (Caenorhabditis elegans) with higher binding energy, comparing to human PEN2. Hence, these results indicated that only the T. spiralis PEN2-ATP6AP1 axis has the potential to be the direct target of low-concentration Met. Together with contribution of host cells including immune cells in vivo, T. spiralis PEN2-ATP6AP1 axis might play roles in reducing parasite load at low-concentration Met. However, the mechanisms of low-concentration Met on other parasitic infections might be mainly achieved by regulating host cells, rather than directly targeting PEN2-ATP6AP1 axis. CONCLUSIONS: These findings revealed the potential mechanisms by which Met treats various parasitic diseases, and shed new light on the development of antiparasitic drugs.

Induction of priming by cold stress via inducible volatile cues in neighboring tea plants.

Plants have evolved sophisticated defense mechanisms to overcome their sessile nature. However, if and how volatiles from cold-stressed plants can trigger interplant communication is still unknown. Here, we provide the first evidence for interplant communication via inducible volatiles in cold stress. The volatiles, including nerolidol, geraniol, linalool, and methyl salicylate, emitted from cold-stressed tea plants play key role(s) in priming cold tolerance of their neighbors via a C-repeat-binding factors-dependent pathway. The knowledge will help us to understand how plants respond to volatile cues in cold stress and agricultural ecosystems.

Scenarios of Genes-to-Terpenoids Network Led to the Identification of a Novel α/ß-Farnesene/ß-Ocimene Synthase in Camellia sinensis.

Terpenoids play vital roles in tea aroma quality and plants defense performance determination, whereas the scenarios of genes to metabolites of terpenes pathway remain uninvestigated in tea plants. Here, we report the use of an integrated approach combining metabolites, target gene transcripts and function analyses to reveal a gene-to-terpene network in tea plants. Forty-one terpenes including 26 monoterpenes, 14 sesquiterpenes and one triterpene were detected and 82 terpenes related genes were identified from five tissues of tea plants. Pearson correlation analysis resulted in genes to metabolites network. One terpene synthases whose expression positively correlated with farnesene were selected and its function was confirmed involved in the biosynthesis of α-farnesene, ß-ocimene and ß-farnesene, a very important and conserved alarm pheromone in response to aphids by both in vitro enzymatic assay in planta function analysis. In summary, we provided the first reliable gene-to-terpene network for novel genes discovery.

Untargeted metabolomics coupled with chemometrics analysis reveals potential non-volatile markers during oolong tea shaking.

Shaking is a critical process in the formation of oolong tea quality, although the metabolites and their changes in this sensitive process have not yet been determined. In this study, untargeted analysis based on ultrahigh-performance liquid chromatography/quadrupole-Orbitrap mass spectrometry was conducted to comprehensively profile metabolite changes in different cultivars. Theanine glucoside was identified for the first time in oolong tea. Hierarchical cluster analysis indicated that shaking caused major changes in metabolite levels in oolong tea. Seventy-one, 83 and 73 potential features showed significant differences between pre- and post-shaking samples for var. sinensiscv. "Zimudan", "Shuixian", and "Huangmeigui," respectively. Chemometrics analysis of the three cultivars led to the identification of 18 shared metabolites, including epigallocatechin gallate, phenylalanine, tryptophan, proline, and hydroxy-jasmonic acid, as potential markers. This study identified the metabolites that allow monitoring of tea quality formation during both processing and preservation, and it provides a novel strategy for data reduction in studies to discover key metabolites.