Understanding the Implications of Anandamide, an Endocannabinoid in an Early Land Plant, Physcomitrella patens

Endocannabinoid signaling is well studied in mammals and known to be involved in numerous pathological and physiological processes. Fatty acid amide hydrolase (FAAH) terminates endocannabinoid signaling in mammals. In Physcomitrella patens, we identified nine orthologs of FAAH (PpFAAH1 to PpFAAH9) with the characteristic catalytic triad and amidase signature sequence. Kinetics of PpFAAH1 showed specificity towards anandamide (AEA) at 37°C and pH 8.0. Further biophysical and bioinformatic analyses revealed that, structurally, PpFAAH1 to PpFAAH4 were closely associated to the plant FAAH whereas PpFAAH6 to PpFAAH9 were more closely associated to the animal FAAH. A substrate entry gate or ‘dynamic paddle’ in FAAH is fully formed in vertebrates but absent or not fully developed in non-vertebrates and plants. In planta analysis revealed that PpFAAH responded differently with saturated and unsaturated N-acylethanolamines (NAEs). In vivo amidohydrolase activity showed specificity associated with developmental stages. Additionally, overexpression of PpFAAH1 indicated the need for NAEs in developmental transition. To understand and identify key molecules related to endocannabinoid signaling in P. patens, we used high-throughput RNA sequencing. We analyzed temporal expression of mRNA and long non-coding RNA (lncRNA) in response not only to exogenous anandamide but also its precursor arachidonic acid and abscisic acid (ABA, a stress hormone). From the 40 RNA-seq libraries generated, we identified 4244 novel lncRNAs. The highest number of differentially expressed genes (DEGs) for both mRNA and lncRNA were detected on short-term exposure (1 h) to AEA. Furthermore, gene ontology enrichment analysis showed that 17 genes related to activation of the G protein-coupled receptor signaling pathway were highly expressed along with a number of genes associated with organelle relocation and localization. We identified key signaling components of AEA that showed significant difference when compared with ABA. This study provides a fundamental understanding of novel endocannabinoid signaling in early land plants and a future direction to elucidate its functional role

Antioxidant and antimicrobial activities of Sonneratia albain vitro and In vivo : comparative study with Rhizophora mucronata and Bruguiera gymnorrhiza / Md. Imdadul Haq

The present study evaluated the antioxidant and antimicrobial potential of three mangrove species namely, Sonneratial alba, Rhizophora mucronat and Bruguiera gymnorrhiza. The bioactivities of methanol, ethanol and chloroform extracts of in vivo and in vitro explants of S. alba and in vivo explants of R. mucronata and B. gymnorrhiza were evaluated. The effects of growth regulators on seed germination of S. alba, to obtain the in vitro explants, were also studied. In the first part of bioactivity study, total phenolic contents were detected by using the Folin-ciocalteu assay. Ethanol extract of leaves of R. mucronata had the highest result for total phenolic content as 358.6 ± 0.53 mg of GAE/g of dry sample. Both enzymatic and non-enzymatic antioxidant assays were used to examine the potential of antioxidant activities of all tested samples. Ethanol and methanol extracts of barks showed better antioxidant activities compared to the leaves. Chloroform extracts in both leaf and bark samples exhibited poor antioxidant activities for all selected mangrove plants. Disc diffusion method was used to detect the antimicrobial activity of the extracts of all three plants. Two gram positive (Bacillus cereus and Staphylococcus aureus) and two gram negative (Escherichia coli and Pseudomonas aeruginosa) bacterial pathogens were used to evaluate antimicrobial activity. Methanol and ethanol extracts of leaves and barks showed promising antimicrobial activities when tested for all four abovementioned bacterial pathogens. Nevertheless, chloroform extracts exhibited poor or no antimicrobial activities against all tested microbial. Ethanol extract of barks of S. alba was fractionated into water and ethyl acetate fraction, and their antioxidant and antimicrobial activities were assessed. Water fraction exhibited better bioactive potential compared with ethyl acetate fraction. Liquid chromatography tandem mass spectrometry (LCMS/MS) analysis was also carried out with water fraction to obtain the nominal mass of the major active components in the water fraction

Tobacco SABP2-Interacting Protein SIP428 is a SIR2 Type Deacetylase

Salicylic acid is widely studied for its role in biotic stress signaling in plants. Several SA-binding proteins, including SABP2 (salicylic acid-binding protein 2) has been identified and characterized for their role in plant disease resistance. SABP2 is a 29 kDA tobacco protein that binds to salicylic acid with high affinity. It is a methylesterase enzyme that catalyzes the conversion of methyl salicylate into salicylic acid required for inducing a robust systemic acquired resistance (SAR) in plants. Methyl salicylic acid is one of the several mobile SAR signals identified in plants. SABP2-interacting protein 428 (SIP428) was identified in a yeast two-hybrid screen using tobacco SABP2 as a bait. In silico analysis shows that SIP428 possesses the SIR2 (silent information regulatory 2)-like conserved motifs. SIR2 enzymes are orthologs of sirtuin proteins that catalyze the NAD+-dependent deacetylation of Nε lysine-acetylated proteins. The recombinant SIP428 expressed in E. coli exhibits SIR2-like deacetylase activity. SIP428 shows homology to Arabidopsis AtSRT2 (67% identity), which is implicated in SA-mediated basal defenses. Immunoblot analysis using anti-acetylated lysine antibodies showed that the recombinant SIP428 is lysine acetylated. The expression of SIP428 transcripts was moderately downregulated upon infection by TMV. In the presence of SIP428, the esterase activity of SABP2 increased modestly. The interaction of SIP428 with SABP2, it\u27s regulation upon pathogen infection, and similarity with AtSRT2 suggests that SIP428 is likely to play a role in stress signaling in plants