Papaya sticky disease, or "meleira", is one of the major diseases of papaya in Brazil and Mexico, capable of causing complete crop loss. The causal agent of sticky disease was identified as an ...isometric virus with a double stranded RNA (dsRNA) genome, named papaya meleira virus (PMeV). In the present study, PMeV dsRNA and a second RNA band of approximately 4.5 kb, both isolated from latex of papaya plants with severe symptoms of sticky disease, were deep-sequenced. The nearly complete sequence obtained for PMeV dsRNA is 8,814 nucleotides long and contains two putative ORFs; the predicted ORF1 and ORF2 display similarity to capsid proteins and RdRp's, respectively, from mycoviruses tentatively classified in the family Totiviridae. The sequence obtained for the second RNA is 4,515 nucleotides long and contains two putative ORFs. The predicted ORFs 1 and 2 display 48% and 73% sequence identity, respectively, with the corresponding proteins of papaya virus Q, an umbravirus recently described infecting papaya in Ecuador. Viral purification in a sucrose gradient allowed separation of particles containing each RNA. Mass spectrometry analysis indicated that both PMeV and the second RNA virus (named papaya meleira virus 2, PMeV2) were encapsidated in particles formed by the protein encoded by PMeV ORF1. The presence of both PMeV and PMeV2 was confirmed in field plants showing typical symptoms of sticky disease. Interestingly, PMeV was detected alone in asymptomatic plants. Together, our results indicate that sticky disease is associated with double infection by PMeV and PMeV2.
A natural deep eutectic solvent (NADES) synthesised from malic acid, xylitol, and water was used as a solvent in ultrasound-assisted extraction (UAE) for the determination of As and Cd in fish and ...shellfish samples by inductively coupled plasma mass spectrometry. The formation of the solvent was confirmed by infrared spectroscopy analysis, which showed the presence of hydrogen bonds between the components. Evaluation was made of elemental determinations performed using standard and kinetic energy discrimination (KED) modes. Higher sensitivity was observed using KED mode, which could be attributed to charge transfer between carbon and the analytes when the NADES introduced into the plasma. The detection limits were 12.7 and 0.100 µg kg
−1
for As and Cd, respectively, and the accuracy of the extraction procedure was assessed by comparing methods. The Cd concentrations in the fish and shellfish samples were below the limits of quantification, while the As concentrations varied between 1.88 and 12.0 µg g
−1
, exceeding the maximum values recommended by regulatory agencies.
The synthesis of a series of 14 new 1-(3-(aryl-4,5-dihydroisoxazol-5-yl)methyl)-4-trihalomethyl-1H-pyrimidin-2-ones from the 1,3-dipolar cycloaddition reaction of ...1-allyl-4-(trihalomethyl)pyrimidin-2(1H)-ones with aryl nitrile oxides is described. Also, the antiproliferative activity of the title compounds was tested against five human tumoral cell lines: MCF-7 breast cancer cell line, ER+ (estrogen receptor positive); HepG-2 (hepatoma); T-24 (bladder cancer); HCT-116 cell (colorectal carcinoma); and CACO-2. The preliminary results are promising, since three compounds presented IC50 values below 2 μM, as well as moderate to high selectivity.
Display omitted
•Synthesis of dihydroisoxazolmethyl-pyrimidines from dipolar cycloaddition reaction.•Antiproliferative activity of dihydroisoxazol-5-yl-(methyl)-1H-pyrimidin-2-ones.•Antiproliferative activity of pyrimidines against five human tumoral cell lines.•Three derivatives showed high activity against HepG-2, T-24, and CACO-2.
A regioselective synthesis of 3-trifluoromethyl-1-phenyl-1H-pyrazoles (1,3-isomers) as well as their 1,5-isomers (5-trifluoromethyl-1-phenyl-1H-pyrazoles), is described. The 1,3-isomers were obtained ...from the reaction of 4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones with arylhydrazones followed by deprotective hydrolysis while the 1,5-isomer was obtained by direct cyclocondensation of 4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones with phenylhydrazine. An unequivocal assignment of the 1,3- and 1,5-isomers of the pyrazole products is given.
To search for new cruzain inhibitors, the synthesis of a series of novel 2-(
N′-benzylidenehydrazino)-4-trifluoromethyl-pyrimidines in a convergent manner is presented. The cruzain inhibitory ...activity of some of these compounds was evaluated and a binding model was proposed. All derivatives tested were active and the most significant inhibitory effect (80% at 100
μM) and IC
50 value (85
μM) were obtained from the 2-(
N′-4-chloro-benzylidenehydrazino)-4-trifluoromethyl-pyrimidine. Although further structural optimization to improve solubility is necessary, the molecular docking studies suggest that these inhibitors occupy the S2 pocket without irreversible enzyme inactivation, through hydrophobic interactions, thus, indicating a desirable mode of interaction for the design of novel inhibitors.
The regioselective synthesis and characterization of a new series of 3‐aryl‐7‐trifluoromethyl1,2,4triazolo4,3–apyrimidines from the oxidative heterocyclization of ...2‐(N′‐benzylidenehydrazino)‐4‐trifluoromethylpyrimidines with copper dichloride is described. J. Heterocyclic Chem., (2011).
The structure of two novel 2-(N'-benzylidenehydrazino)-4-trifluoromethyl-pyrimidines has been determined by X-ray crystallography and their energy-minimized structures were stablished by molecular ...orbital calculations (AM1) by means of comparison. Additionally, the bond lengths of the compounds were analyzed in order to verify the occurance of electronic resonance. Bond lengths and bond angles in the pyrimidine ring and the benzylidene portion compare well with those found in similar compounds. 2-(N'-benzylidenehydrazino)-4-trifluoromethyl-pyrimidine, crystallized in the triclinic space group P-1 solvated with a molecule of water, while 2-(N'-2-methyl-benzylidenehydrazino)-5-methyl-4- trifluoromethyl-pyrimidine crystallized in the tetragonal space group P41. The azomethine moieties showed a trans-planar conformation. The energy-minimized structures of both compounds are in good agreement with their X-ray crystal structures. Nevertheless, a significant difference between calculated and experimental data regarding to the ring planarity was observed due to relevant intermolecular interactions in the real structures. Finally, aromaticities of both pyrimidines and phenyl rings were determined using HOMA calculations.
PDF
