Phosphoethanolamine N-methyltransferase Research Articles

Evaluation of the novel endophytic fungus Chaetomium ascotrichoides 1-24-2 from Pinus massoniana as a biocontrol agent against pine wilt disease caused by Bursaphelenchus xylophilus.

Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD), is an ever-increasing threat to Pinus forests worldwide. This study aimed to develop biological control of PWD by the application of endophytic fungi isolated from healthy pine trees. We successfully isolated a novel endophytic fungal strain 1-24-2 from branches of healthy Pinus massoniana. The culture filtrates (CFs) of strain 1-24-2 exhibited strong nematicidal activity against Bursaphelenchus xylophilus, with a corrected mortality rate of 99.00%. Based on the morphological and molecular characteristics, the isolated strain 1-24-2 was identified as Chaetomium ascotrichoides. In the in-planta assay, pine seedlings (2-years-old) treated with 1-24-2 CFs + pine wood nematode (T2) showed a significant control effect of 80%. A total of 24 toxic compounds were first identified from 1-24-2 CFs through gas chromatography-mass spectrometry (GC-MS) analysis, from which O-methylisourea, 2-chlorobenzothiazole, and 4,5,6-trihydroxy-7-methylphthalide showed robust binding sites at Tyr119 against phosphoethanolamine methyltransferase (PMT) protein of Bursaphelenchus xylophilus by molecular docking approach and could be used as potential compounds for developing effective nematicides. Interestingly, strain 1-24-2 produces toxic volatile organic compounds (VOCs), which disturb the natural development process of B. xylophilus, whose total number decreased by up to 83.32% in the treatment group as compared to control and also reduced Botrytis cinerea growth by up to 71.01%. Our results highlight the potential of C. ascotrichoides 1-24-2 as a promising biocontrol agent with solid nematicidal activity against B. xylophilus. This is the first report of C. ascotrichoides isolated from P. massoniana exhibiting strong biocontrol potential against B. xylophilus in the world. © 2024 Society of Chemical Industry.

In silico analysis of soybean phytocompounds against Plasmodium falciparum

IntroductionNatural products have been indispensable since immemorial and still act as a supportive healer. Parasitic diseases are a significant hurdle for humans and are responsible for global morbidity and mass mortality. Due to the building up of resistance in parasites over existing drugs and the severe side effects of the drugs, there is an urgent need to explore various plant extracts to discover novel antiparasitic agents. This article deals with the pharmacological aspects of soybeans against Plasmodium falciparum, which causes many of the deadliest and most popular diseases, such as malaria. MethodsThe molecular basis for selective inhibition of soy phytoconstituents like beta-sitosterol, soya-saponin I, soya-saponin II, soya-saponin II methyl ester, dehydrosoyasaponin I, phytic acid, and tryptophyl leucine were evaluated using in silico molecular docking approaches and molecular dynamic simulations against the falcipain-2 (FP2) and phosphoethanolamine methyltransferase (PMT) of P. falciparum. ResultsThe results indicated that tryptophyl leucine exhibited potential inhibitory action against both enzymes based on pharmacophore, molecular docking, simulations, root mean square deviation, root mean square fluctuations, absorption, distribution, metabolism, excretion, and toxicity analyses. ConclusionMedicinal plants represent a treasure for bioactive lead compounds and eventually provide scope for further identification and investigation of novel drug candidates which may be important in the design of selective PfPMT/PfFP-2 inhibitors as potential antimalarials.

Antimalarial and Antileishmanial Flavonoids from Calendula officinalis Flowers

Calendula officinalis L. (Asteraceae), commonly known as English or pot marigold, is an herbaceous plant with edible flowers. In this study, UPLC-ESI-MS/MS analysis was used for tentative identification of compounds in marigold flower methanol extract (MFE). In addition, RP-HPLC-DAD analysis was used to quantify the flavonoids hesperidin and rutin in MFE. The antileishmanial potentials of the crude extract and compounds were evaluated against Leishmania major promastigotes and amastigotes. Further, in vivo 4-day antimalarial testing of the extract and compounds was carried out at doses of 25 mg kg−1 per day using mice infected with ANKA strain of Plasmodium berghei, following standard procedure. Molecular docking studies were carried out to assess the binding mode of flavonoids against the vital targets of L. major, including pteridine reductase 1 and farnesyl diphosphate synthase enzymes. The in silico antimalarial potentials of flavonoids were evaluated against wild-type Plasmodium falciparum dihydrofolate reductase-thymidylate synthase and phosphoethanolamine methyltransferase enzymes. Twenty compounds were tentatively identified by UPLC-ESI-MS/MS analysis of MFE, of which, seven flavonoids, six saponins, three phenolic acids, three fatty acids, and a triterpene glycoside were identified. MFE phytochemical analysis revealed that hesperidin content was 36.17 mg g−1 extract, that is, 9.9-fold their content of rutin (3.65 mg g−1 extract). The method was validated to ensure reproducibility of the results. The tested samples exhibited antileishmanial potentials against L. major promastigotes, with IC50 values of 98.62, 118.86, and 104.74 ng µL−1 for hesperidin, rutin, and MFE, respectively. Likewise, hesperidin showed inhibitory potentials against L. major amastigote with an IC50 value of 108.44 ± 11.2 µM, as compared to miltefosine. The mean survival time, parasitemia, and suppression percentages showed similar results for the three samples against ANKA strain of P. berghei. The docking studies showed good binding affinities of rutin and hesperidin with numerous H-bonding and van der Waals interactions. Marigold flowers are nutraceuticals, presenting important sources of bioactive flavonoids with potential against neglected tropical diseases.

Discovery of dual-target natural antimalarial agents against DHODH and PMT of Plasmodium falciparum: pharmacophore modelling, molecular docking, quantum mechanics, and molecular dynamics simulations

ABSTRACT Malaria is a lethal disease that claims thousands of lives worldwide annually. The objective of this study was to identify new natural compounds that can target two P. falciparum enzymes; P. falciparum Dihydroorotate dehydrogenase (PfDHODH) and P. falciparum phosphoethanolamine methyltransferase (PfPMT). To accomplish this, e-pharmacophore modelling and molecular docking were employed against PfDHODH. Following this, 1201 natural compounds with docking scores of ≤ −7 kcal/mol were docked into the active site of the second enzyme PMT. The top nine compounds were subjected to further investigation using MM-GBSA free binding energy calculations and ADME analysis. The results revealed favourable free binding energy values better than the references, as well as acceptable pharmacokinetic properties. Compounds ZINC000013377887, ZINC000015113777, and ZINC000085595753 were scrutinized to assess their interaction stability with the PfDHODH enzyme, and chemical stability reactivity using molecular dynamics (MD) simulation and density functional theory (DFT) calculations. These findings indicate that the three natural compounds are potential candidates for dual PfDHODH and PfPMT inhibitors for malaria treatment.

Sexual differentiation in human malaria parasites is regulated by competition between phospholipid metabolism and histone methylation.

For Plasmodium falciparum, the most widespread and virulent malaria parasite that infects humans, persistence depends on continuous asexual replication in red blood cells, while transmission to their mosquito vector requires asexual blood-stage parasites to differentiate into non-replicating gametocytes. This decision is controlled by stochastic derepression of a heterochromatin-silenced locus encoding AP2-G, the master transcription factor of sexual differentiation. The frequency of ap2-g derepression was shown to be responsive to extracellular phospholipid precursors but the mechanism linking these metabolites to epigenetic regulation of ap2-g was unknown. Through a combination of molecular genetics, metabolomics and chromatin profiling, we show that this response is mediated by metabolic competition for the methyl donor S-adenosylmethionine between histone methyltransferases and phosphoethanolamine methyltransferase, a critical enzyme in the parasite's pathway for de novo phosphatidylcholine synthesis. When phosphatidylcholine precursors are scarce, increased consumption of SAM for de novo phosphatidylcholine synthesis impairs maintenance of the histone methylation responsible for silencing ap2-g, increasing the frequency of derepression and sexual differentiation. This provides a key mechanistic link that explains how LysoPC and choline availability can alter the chromatin status of the ap2-g locus controlling sexual differentiation.

Broad-Spectrum Inhibitors for Conserved Unique Phosphoethanolamine Methyltransferases in Parasitic Nematodes Possess Anthelmintic Efficacy.

In humans, nematode infections are prevalent in developing countries, causing long-term ill health, particularly in children. Worldwide, nematode infections are prevalent in livestock and pets, affecting productivity and health. Anthelmintic drugs are the primary means of controlling nematodes, but there is now high prevalence of anthelmintic resistance, requiring urgent identification of new molecular targets for anthelmintics with novel mechanisms of action. Here, we identified orthologous genes for phosphoethanolamine methyltransferases (PMTs) in nematodes within the families Trichostrongylidae, Dictyocaulidae, Chabertiidae, Ancylostomatoidea, and Ascarididae. We characterized these putative PMTs and found that they possess bona fide PMT catalytic activities. By complementing a mutant yeast strain lacking the ability to synthesize phosphatidylcholine, the PMTs were validated to catalyze the biosynthesis of phosphatidylcholine. Using an in vitro phosphoethanolamine methyltransferase assay with PMTs as enzymes, we identified compounds with cross-inhibitory effects against the PMTs. Corroboratively, treatment of PMT-complemented yeast with the PMT inhibitors blocked growth of the yeast, underscoring the essential role of the PMTs in phosphatidylcholine synthesis. Fifteen of the inhibitors with the highest activity against complemented yeast were tested against Haemonchus contortus using larval development and motility assays. Among them, four were found to possess potent anthelmintic activity against both multiple drug-resistant and susceptible isolates of H. contortus, with IC50 values (95% confidence interval) of 4.30 μM (2.15-8.28), 4.46 μM (3.22-6.16), 28.7 μM (17.3-49.5), and 0.65 μM (0.21-1.88). Taken together, we have validated a molecular target conserved in a broad range of nematodes and identified its inhibitors that possess potent in vitro anthelmintic activity.

Functional analysis of phosphoethanolamine N-methyltransferase in plants and parasites: Essential S-adenosylmethionine-dependent methyltransferase in choline and phospholipid metabolism.

Phospholipids play an essential role as a barrier between cell content and the extracellular environment and regulate various cell signaling processes. Phosphatidylcholine (PtdCho) is one of the most abundant phospholipids in plant, animal, and some prokaryote cell membranes. In plants and some parasites, the biosynthesis of PtdCho begins with the amino acid serine, followed mainly through a phosphoethanolamine N-methyltransferase (PMT)-mediated biosynthetic pathway to phosphocholine (pCho). Because the PMT-mediated pathway, referred to as the phosphobase methylation pathway, produces a series of important primary and specialized metabolites for plant development and stress response, understanding the PMT enzyme is a key aspect of engineering plants with improved stress tolerance and fortified nutrients. Importantly, given the very limited phylogenetic distribution of PMTs, functional analysis and the identification of inhibitors targeting PMTs have potential and positive impacts in humans and in veterinary and agricultural fields. Here, we describe detailed basic knowledge and practical research methods to enable the systematic study of the biochemical and biophysical functions of PMT. The research methods described in this chapter are also applicable to the studies of other ubiquitous S-adenosyl-l-methionine (SAM)-dependent methyltransferases in all kingdoms.

Abscisic acid-dependent PMT1 expression regulates salt tolerance by alleviating abscisic acid-mediated reactive oxygen species production in Arabidopsis.

Phosphocholine (PCho) is an intermediate metabolite of nonplastid plant membranes that is essential for salt tolerance. However, how PCho metabolism modulates response to salt stress remains unknown. Here, we characterize the role of phosphoethanolamine N-methyltransferase 1 (PMT1) in salt stress tolerance in Arabidopsis thaliana using a T-DNA insertional mutant, gene-editing alleles, and complemented lines. The pmt1 mutants showed a severe inhibition of root elongation when exposed to salt stress, but exogenous ChoCl or lecithin rescued this defect. pmt1 also displayed altered glycerolipid metabolism under salt stress, suggesting that glycerolipids contribute to salt tolerance. Moreover, pmt1 mutants exhibited altered reactive oxygen species (ROS) accumulation and distribution, reduced cell division activity, and disturbed auxin distribution in the primary root compared with wild-type seedlings. We show that PMT1 expression is induced by salt stress and relies on the abscisic acid (ABA) signaling pathway, as this induction was abolished in the aba2-1 and pyl112458 mutants. However, ABA aggravated the salt sensitivity of the pmt1 mutants by perturbing ROS distribution in the root tip. Taken together, we propose that PMT1 is an important phosphoethanolamine N-methyltransferase participating in root development of primary root elongation under salt stress conditions by balancing ROS production and distribution through ABA signaling.

Structural and biochemical analysis of phosphoethanolamine methyltransferase from the pine wilt nematode Bursaphelenchus xylophilus

In free‐living and parasitic nematodes, the methylation of phosphoethanolamine to phosphocholine provides a key metabolite to sustain phospholipid biosynthesis for growth and development. Because the phosphoethanolamine methyltransferases (PMT) of nematodes are essential for normal growth and development, these enzymes are potential targets of inhibitor design. The pine wilt nematode (Bursaphelenchus xylophilus) causes extensive damage to trees used for lumber and paper in Asia. As a first step toward testing BxPMT1 as a potential nematicide target, we determined the 2.05 Å resolution x‐ray crystal structure of the enzyme as a dead‐end complex with phosphoethanolamine and S‐adenosylhomocysteine. The three‐dimensional structure of BxPMT1 served as a template for site‐directed mutagenesis to probe the contribution of active site residues to catalysis and phosphoethanolamine binding using steady‐state kinetic analysis. Biochemical analysis of the mutants identifies key residues on the β1d‐α6 loop (W123F, M126I, and Y127F) and β1e‐α7 loop (S155A, S160A, H170A, T178V, and Y180F) that form the phosphobase binding site and suggest that Tyr127 facilitates the methylation reaction in BxPMT1.

Adaptive capacity to dietary Vitamin B12 levels is maintained by a gene-diet interaction that ensures optimal life span.

Diet regulates complex life‐history traits such as longevity. For optimal lifespan, organisms employ intricate adaptive mechanisms whose molecular underpinnings are less known. We show that Caenorhabditis elegans FLR‐4 kinase prevents lifespan differentials on the bacterial diet having higher Vitamin B12 levels. The flr‐4 mutants are more responsive to the higher B12 levels of Escherichia coli HT115 diet, and consequently, have enhanced flux through the one‐carbon cycle. Mechanistically, a higher level of B12 transcriptionally downregulates the phosphoethanolamine methyltransferase pmt‐2 gene, which modulates phosphatidylcholine (PC) levels. Pmt‐2 downregulation activates cytoprotective gene expression through the p38‐MAPK pathway, leading to increased lifespan only in the mutant. Evidently, preventing bacterial B12 uptake or inhibiting one‐carbon metabolism reverses all the above phenotypes. Conversely, supplementation of B12 to E. coli OP50 or genetically reducing PC levels in the OP50‐fed mutant extends lifespan. Together, we reveal how worms maintain adaptive capacity to diets having varying micronutrient content to ensure a normal lifespan.

PI4-kinase and PfCDPK7 signaling regulate phospholipid biosynthesis in Plasmodium falciparum.

PfCDPK7 is an atypical member of the calcium-dependent protein kinase (CDPK) family and is crucial for the development of Plasmodium falciparum. However, the mechanisms whereby PfCDPK7 regulates parasite development remain unknown. Here, we perform quantitative phosphoproteomics and phospholipid analysis and find that PfCDPK7 promotes phosphatidylcholine (PC) synthesis by regulating two key enzymes involved in PC synthesis, phosphoethanolamine-N-methyltransferase (PMT) and ethanolamine kinase (EK). In the absence of PfCDPK7, both enzymes are hypophosphorylated and PMT is degraded. We further find that PfCDPK7 interacts with 4'-phosphorylated phosphoinositides (PIPs) generated by PI4-kinase. Inhibition of PI4K activity disrupts the vesicular localization PfCDPK7. P.falciparum PI4-kinase, PfPI4K is a prominent drug target and one of its inhibitors, MMV39048, has reached Phase I clinical trials. Using this inhibitor, we demonstrate that PfPI4K controls phospholipid biosynthesis and may act in part by regulating PfCDPK7 localization and activity. These studies not only unravel a signaling pathway involving PfPI4K/4'-PIPs and PfCDPK7 but also provide novel insights into the mechanism of action of a promising series of candidate anti-malarial drugs.

Cloning and Functional Identification of Phosphoethanolamine Methyltransferase in Soybean (Glycine max).

Phosphoethanolamine methyltransferase (PEAMT), a kind of S-adenosylmethionine-dependent methyltransferases, plays an essential role in many biological processes of plants, such as cell metabolism, stress response, and signal transduction. It is the key rate-limiting enzyme that catalyzes the three-step methylation of ethanolamine-phosphate (P-EA) to phosphocholine (P-Cho). To understand the unique function of PEAMT in soybean (Glycine max) lipid synthesis, we cloned two phosphoethanolamine methyltransferase genes GmPEAMT1 and GmPEAMT2, and performed functional identification. Both GmPEAMT1 and GmPEAMT2 contain two methyltransferase domains. GmPEAMT1 has the closest relationship with MtPEAMT2, and GmPEAMT2 has the closest relationship with CcPEAMT. GmPEAMT1 and GmPEAMT2 are located in the nucleus and endoplasmic reticulum. There are many light response elements and plant hormone response elements in the promoters of GmPEAMT1 and GmPEAMT2, indicating that they may be involved in plant stress response. The yeast cho2 opi3 mutant, co-expressing Arabidopsis thaliana phospholipid methyltransferase (PLMT) and GmPEAMT1 or GmPEAMT2, can restore normal growth, indicating that GmPEAMTs can catalyze the methylation of phosphoethanolamine to phosphate monomethylethanolamine. The heterologous expression of GmPEAMT1 and GmPEAMT2 can partially restore the short root phenotype of the Arabidopsis thaliana peamt1 mutant, suggesting GmPEAMTs have similar but different functions to AtPEAMT1.

Overexpression of the pitaya phosphoethanolamine N-methyltransferase gene (HpPEAMT) enhanced simulated drought stress in tobacco

Phosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.

Structural and biochemical analysis of phosphoethanolamine methyltransferase from the pine wilt nematode Bursaphelenchus xylophilus

In free-living and parasitic nematodes, the methylation of phosphoethanolamine to phosphocholine provides a key metabolite to sustain phospholipid biosynthesis for growth and development. Because the phosphoethanolamine methyltransferases (PMT) of nematodes are essential for normal growth and development, these enzymes are potential targets of inhibitor design. The pine wilt nematode (Bursaphelenchus xylophilus) causes extensive damage to trees used for lumber and paper in Asia. As a first step toward testing BxPMT1 as a potential nematicide target, we determined the 2.05 Å resolution x-ray crystal structure of the enzyme as a dead-end complex with phosphoethanolamine and S-adenosylhomocysteine. The three-dimensional structure of BxPMT1 served as a template for site-directed mutagenesis to probe the contribution of active site residues to catalysis and phosphoethanolamine binding using steady-state kinetic analysis. Biochemical analysis of the mutants identifies key residues on the β1d-α6 loop (W123F, M126I, and Y127F) and β1e-α7 loop (S155A, S160A, H170A, T178V, and Y180F) that form the phosphobase binding site and suggest that Tyr127 facilitates the methylation reaction in BxPMT1.

LEAD MOLECULE IDENTIFICATION FROM VITEX TRIFOLIA LINN FOR HELMINTHIASIS USING IN VITRO AND IN SILICO METHODS

Objective: The study was an attempt to discover a lead molecule to treat helminthiasis using Vitex trifolia. Linn (V. folia Linn) through sterile effect, in vitro and in silico evaluation.
 Methods: The antibacterial activity was done by Kirby-Bauer disc diffusion method in three different concentrations of extract and in vitro anthelmintic activity was carried out by petri dish and organ bath method. Further, the in silico docking studies were carried out by 11 phytoconstituents against phosphoethanolamine methyltransferase (4FGZ) using Auto Dock 4.2, it was working based on the principle of Lamarckian genetic algorithm. In docking studies, three important parameters such as binding energy, inhibition constant and intermolecular energy are determined.
 Results: The extracts showed an antibacterial effect in three different concentrations. At 16 mcg/disc a significant effect was observed when compared to blank and ciprofloxacin 5 mcg/disc. The anthelmintic activity in the petri dish method, means paralyzing time of Pheretimaposthuma with the dose of 25, 50 and 100 mg/ml were 13.78, 5.79 and 4.57 min respectively and Piperazine citrate (10 mg/ml) showed paralysis in 21.58 min. In the organ bath method, the time for paralysis of the worm was recorded on a slow-moving Sherrington rotating drum and the study report showed that paralyzing time was decreased at increasing concentrations of the extract. The results of in silico studies exhibited a binding energy of-10.25kcal/mol, inhibitory constant (Ki) 30.91nM, intermolecular energy,-10.84kcal/mol for abietatriene-3-ol which is lesser than the standard ligand phosphoethanolamine (-6.03kcal/mol, 38.29µM,-7.82kcal/mol) respectively.
 Conclusion: The study reports conclude that the active constituents in V. folia Linn having better anthelmintic activity, thus the active constituents may be optimized and make way to a new moiety for the treatment of helminthiasis.

Implication of serine-decarboxylase-phosphoethanolamine-methyltransferase Pathway and phosphoethanolamine-methyltransferase in Malaria abolition

The growing resistance to current antimalarial drugs is a major concern for global public health, demands the novel essential regulatory pathway of plasmodium to be targeted for new potent antimalarial development. The biological processes that regulate both growth and gametocytogenesis of plasmodium still remain unknown. Identification and thorough understanding of such pathways is crucial to the development of a new generation of dual activity antimalarials that can inhibit both infection and transmission. There one pathway responsible for phosphatidylcholine (PC) a phospholipid biosynthesis in Bacteria, eukaryotes and plants through different routes, has also been elucidated in plasmodium. Plasmodium normally synthesizes PC for membrane development from choline through CDP-choline route but at infection stage in host it needs faster development of PC abundantly for membrane development from serine of the host blood through plant like serine-decarboxylase-phosphoethanolamine-methyltransferase (SDPM) alternate pathway absent in human host. Phosphoethanolamine methyltransferase (PMT) an enzyme crucial for catalyzing trimethylation, a rate limiting step to synthesize PC is a promising target for research on a novel class of antimalarials. In this review, we have emphasized development of PC biosynthesis through SDPM pathway and the significance of PC in Plasmodium to provide novel directions in which research might be most beneficial. We also focused on important perspectives and applicability of PMTs as therapeutic target for structure-based drug designing for PMT inhibitor discovery as antimalarials.

Computational and experimental elucidation of Plasmodium falciparum phosphoethanolamine methyltransferase inhibitors: Pivotal drug target.

IntroductionPlasmodium falciparum synthesizes phosphatidylcholine for the membrane development through serine decarboxylase–phosphoethanolamine methyltransferase pathway for growth in human host. Phosphoethanolamine-methyltransferase (PfPMT) is a crucial enzyme for the synthesis of phosphocholine which is a precursor for phosphatidylcholine synthesis and is considered as a pivotal drug target as it is absent in the host. The inhibition of PfPMT may kill malaria parasite and hence is being considered as potential target for rational antimalarial drug designing.MethodsIn this study, we have used computer aided drug designing (CADD) approaches to establish potential PfPMT inhibitors from Asinex compound library virtually screened for ADMET and the docking affinity. The selected compounds were tested for in-vitro schizonticidal, gametocidal and cytotoxicity activity. Nontoxic compounds were further studied for PfPMT enzyme specificity and antimalarial efficacy for P. berghei in albino mice model.ResultsOur results have identified two nontoxic PfPMT competitive inhibitors ASN.1 and ASN.3 with better schizonticidal and gametocidal activity which were found to inhibit PfPMT at IC50 1.49μM and 2.31μM respectively. The promising reduction in parasitaemia was found both in orally (50 & 10 mg/kg) and intravenous (IV) (5& 1 mg/kg) however, the better growth inhibition was found in intravenous groups.ConclusionWe report that the compounds containing Pyridinyl-Pyrimidine and Phenyl-Furan scaffolds as the potential inhibitors of PfPMT and thus may act as promising antimalarial inhibitor candidates which can be further optimized and used as leads for template based antimalarial drug development.

Phosphoethanolamine N-methyltransferase 1 contributes to maintenance of root apical meristem by affecting ROS and auxin-regulated cell differentiation in Arabidopsis.

The continuous growth of roots requires the balance between cell division and differentiation. Reactive oxygen species (ROS) and auxin are important regulators of root development by affecting cell division and differentiation. The mechanism controlling the coordination of cell division and differentiation is not well understood. Using a forward genetic screen, we isolated a mutant, defective primary root 2 (dpr2), defective in root apical meristem (RAM) maintenance. The DPR2 gene encodes phosphoethanolamine N-methyltransferase 1 (PEAMT1) that catalyzes phosphocholine biosynthesis in Arabidopsis. We characterized the primary root phenotypes of dpr2 using various marker lines, using histochemical and pharmacological analysis to probe early root development. Loss-of-function of DPR2/PEAMT1 resulted in RAM consumption by affecting root stem cell niche, division zone, elongation and differentiation zone (EDZ). PIN-FORMED (PIN) protein abundance, PIN2 polar distribution and general endocytosis were impaired in the root tip of dpr2. Excess hydrogen peroxide and auxin accumulate in the EDZ of dpr2, leading to RAM consumption by accelerating cell differentiation. Suppression of ROS over-accumulation or inhibition of auxin signalling partially prevent RAM differentiation in dpr2 after choline starvation. Taken together, we conclude that the EDZ of the root tip is most sensitive to choline shortage, leading to RAM consumption through an ROS-auxin regulation module.

Docking predictions based Plasmodium falciparum phosphoethanolamine methyl transferase inhibitor identification and in-vitro antimalarial activity analysis

The increased multidrug resistance among antimalarial drugs produces the urgency of potent anti malarial to combat resistant malaria and the malaria burden worldwide. The protein which may prevent the growth or transmission of malaria parasite may be the great target for rational drug designing. Plasmodium falciparum phosphoethanolamine methyltransferase (Pfpmt) absent in human catalyzes triple methylation of ethanolamine into phosphocholine for phosphatidylcholine biosynthesis from serine decarboxylation phosphoethanolamine methyltransferase pathway for the membrane development at asexual as well as sexual stages of parasite. The Plasmodium requires production of membrane rapidly for growth and multiplication. Hence, the phosphoethanolamine methyltransferase of Plasmodium falciparum was selected as drug target for rational drug designing. Using Discovery studio 3.5 software the library of zinc compounds was screened against target and analyzed. The compounds with better druglike properties and docking affinity and binding interaction for target protein were procured for in vitro analysis against Plasmodium falciparum culture (IC50). Compounds ZINC02103914 and ZINC12882412 were found to have good druglike properties and affinity for Pfpmt also inhibited P. falciparum growth at very low µM IC50 concentration 3.0 µM and 2.1 µM respectively also found nontoxic in vitro against HEK-293 cells. Simulation study of best inhibitor revealed the specificity for the target protein. Hence, the compounds possessed the immense probability of being inhibitors of Pfpmt and may be optimized as antimalarial agent for combinational therapy to overcome the multidrug resistance and may also be used as template for optimization and rational drug designing.

Functional Characterization and Evolutionary Analysis of Glycine-Betaine Biosynthesis Pathway in Red Seaweed Pyropia yezoensis.

The red seaweed Pyropia yezoensis is an ideal research model for dissecting the molecular mechanisms underlying its robust acclimation to abiotic stresses in intertidal zones. Glycine betaine (GB) was an important osmolyte in maintaining osmotic balance and stabilizing the quaternary structure of complex proteins under abiotic stresses (drought, salinity, etc.) in plants, animals, and bacteria. However, the existence and possible functions of GB in Pyropia remain elusive. In this study, we observed the rapid accumulation of GB in desiccated Pyropia blades, identifying its essential roles in protecting Pyropia cells against severe osmotic stress. Based on the available genomic and transcriptomic information of Pyropia, we computationally identified genes encoding the three key enzymes in the GB biosynthesis pathway: phosphoethanolamine N-methyltransferase (PEAMT), choline dehydrogenase (CDH), and betaine aldehyde dehydrogenase (BADH). Pyropia had an extraordinarily expanded gene copy number of CDH (up to seven) compared to other red algae. Phylogeny analysis revealed that in addition to the one conservative CDH in red algae, the other six might have originated from early gene duplication events. In dehydration stress, multiple CDH paralogs and PEAMT genes were coordinating up-regulated and shunted metabolic flux into GB biosynthesis. An elaborate molecular mechanism might be involved in the transcriptional regulation of these genes.