Susceptibility Against Grey Blight Disease-Causing Fungus Pestalotiopsis sp. in Tea (Camellia sinensis (L.) O. Kuntze) Cultivars Is Influenced by Anti-oxidative Enzymes

Reactive oxygen species (ROS) production is the first level of response by a host during stress. Even though the ROS are toxic to cell, when present in a limited amount, they act as a signalling molecule for the expression of defence-related genes and later are scavenged by either enzymatic or non-enzymatic mechanisms of the host. The different anti-oxidative enzymes like glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APO), peroxidase (POD) and polyphenol oxidase (PPO) were estimated, and their activities were compared between infected and healthy leaves of the tolerant and susceptible cultivars of tea. The infected leaves of the susceptible cultivars registered higher amount of enzyme activity when compared with the tolerant cultivars. The study reveals that the more anti-oxidative enzymes, the more susceptible the cultivar will be.     

Selective fluorination of m-tyrosine by OF2

Fluorine-18 labeled aromatic amino acids are routinely used as tracers in positron emission tomography (PET) to study in vivo metabolic processes. The most versatile method for the production of such radiotracers is electrophilic fluorination of the aromatic amino acid with [¹⁸F]F₂, which is most commonly produced by the gas-phase nuclear reaction ¹⁸O(p, n)¹⁸F. Although [¹⁸F]F₂ is the major product, considerable amounts of [¹⁸F]OF₂ (up to 20%) are also produced. Electrophilic fluorination reactions of l-phenylalanine, 3-nitro-l-tyrosine, 4-nitro-dl-phenylalanine, 3,4-dihydroxyphenyl-l-alanine (l-DOPA), 3-O-methyl-l-DOPA, 3,4-dimethoxy-l-phenylalanine, p-tyrosine and o-tyrosine in H₂O and of m-tyrosine in anhydrous HF (aHF), CF₃SO₃H, CF₃COOH, CH₃COOH, HCOOH and H₂O using OF₂ were investigated. Although F₂ is an efficient fluorinating agent in aHF, electrophilic fluorination reactions using OF₂ were shown to be most efficient in less acidic media such as H₂O. In addition, and contrary to reports that OF₂ and F₂ have similar reactivities, m-tyrosine was the only aromatic system studied that was fluorinated by OF₂ and this was optimum in H₂O for the fluorinated m-tyrosine isomers (total yield, 4.35 ± 0.04%). The presence of [¹⁸F]OF₂ byproduct has no significant impact on the fluorination of aromatic amino acids investigated in this study and the subsequent production of their corresponding ¹⁸F-labeled radiotracers for patient use.     

Simultaneous determination of one nonionic and two anionic surfactants using Fourier transform infrared spectrometry and multivariate analysis

A direct and reagent free procedure for simultaneous determination of sodium lauryl ether sulfate (SLES), coconut diethanol amide (CDEA) and linear alkylbenzene sulfonate (LABS) in undiluted samples of hand dishwashing liquids has been developed. This determination was carried out by using attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR) and multivariate analysis. An implementation of the PLS statistical approach to quantitative analysis of one nonionic and two anionic surfactants was applied to a set of mid-infrared spectra (1305-990 cm(-1)) recorded for commercial detergent samples and ternary standard solutions. An orthogonal calibration design for three components and five levels for standards were employed. Number of factors and scans and also the resolution were optimized. The statistical parameters such as the root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), standard error of prediction (SEP) and relative standard deviation (R.S.D.) were evaluated. These parameters were obtained as: RMSEC 0.13, 0.20 and 0.14, RMSEV 0.09, 0.17 and 0.04 and SEP 0.12, 0.39 and 0.18 (g per 100 g) for SLES, CDEA and LABS, respectively. R.S.D. for five independent analyses were 1.69 for SLES, 3.76 for CDEA and 1.76 for LABS. The component linear correlation coefficients comparing actual and predicted concentrations of SLES, CDEA and LABS in some real samples were 0.9995, 0.9915 and 0.9974, respectively.     

Differential electrochemical behaviour of phytofabricated and chemically synthesized silver nanoparticles towards hydrogen peroxide sensing**

Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials for biomedical applications. However, the impact of its synthesis by chemical and plant-mediated routes on its differential electrochemical behaviour has not been examined till date. Here, we report for the first time the differential study of the electrochemical behaviour of the AgNPs synthesized by different routes. First, the AgNPs were obtained by different routes (chemical and phytofabrication) and extensively characterized to compare their physical properties. Thereafter, a comparison of electron transfer kinetics between chemically synthesized (Ag−C) and phyto-fabricated (Ag-Phy) nanoparticles (NPs) has been studied by electrochemical techniques such as potentiodynamic cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). To further investigate the electrocatalytic properties of both types of AgNPs, we have used the peroxide moieties (H₂O₂), and the Ag−C NPs-based sensor probe has been reported to have four times better sensitivity than the Ag−Phy NPs-based sensor. The AgNPs modified sensor probes have also been tested in real-world environments to explore the consistency of their performance in complex matrices by using clinical urine samples, where we found comparable sensitivity to the standard conditions.     

Preparation,characterization and analysis of novel polyimides with anthracene,carbazole and fluorene pendent architecture

Two series of new organosoluble and thermally stable polyimides containing anthracene, and fluorene pendants were prepared by a two-step solution polycondensation reaction of new synthesized diamines with commercially available dianhydrides. All intermediates and polymers were fully characterized by FTIR, NMR, and elemental analysis and their properties including solubility and thermal stability were studied. All the resulting polymers were amorphous with inherent viscosities ranged from 0.61 to 0.84 dL/g and were readily soluble in many organic solvents.     

Synthesis and antimicrobial activity of quinoline-based 2-pyrazolines

A series of 2-pyrazolines was prepared in a reaction of quinolinylchalcones with phenyl hydrazine under both conventional and microwave-induced heating. Structures of the synthesized compounds were characterized by spectroscopic data and CHN analyses. All prepared compounds were tested for antimicrobial activity against bacterial strains, viz. Staphylococcus aureus, Salmonella typhii, Escherichia coli, and Shigella dysentery. Almost all synthesized compounds have shown antimicrobial activity; however, compounds with a chloro group as a substituent have been found to be more effective.     

Efficient electrocatalytic oxidation and selective determination of isoniazid by Fe(tmphen) 3 2+ -exchanged Nafion?-modified electrode

Cyclic voltammetry and electrochemical impedance studies of Fe(tmphen) ₃ ²⁺ (where tmphen?=?3,4,7,8-tetramethyl-1,10-phenanthroline)-immobilized Nafion?-modified glassy carbon electrode (GC/Nf/Fe(tmphen) ₃ ²⁺ ) are carried out in 0.1?M Na₂SO₄ solution. Nafion–Fe(tmphen) ₃ ²⁺ complex exhibits efficient electrocatalytic oxidation of isoniazid. The linear double reciprocal plot of current and concentration of isoniazid shows a Michaelis–Menten-type catalytic process. The catalytic oxidation currents are proportional to the concentration of isoniazid and show a wide linear calibration range for the quantitative determination of isoniazid. Detection limit and sensitivity are found to be 13?μM and 2.5?μA?mM^?1, respectively.     

Structural and Docking Studies of a Nucleoside Diphosphate Kinase 1 (CsNDPK1) from Tea [Camellia sinensis (L.) O. Kuntze]

Nucleoside diphosphate kinase (NDPK, EC 2.7.4.6) is a housekeeping gene, which functions in the general homeostasis of cellular nucleoside triphosphate (NTP) pools. Among the various NDPK isoforms, cytosolic NDPK1 has been shown to be the main NDPK isoform in plants, accounting for more than 70?% of total NDPK activity in plants. For the first time, a full-length cDNA (697?bp), designated as CsNDPK1 was cloned from tea leaves and consisted of a 448-bp open reading frame (ORF) encoding a 147-amino-acid polypeptide with calculated molecular mass of 16.1?kDa and a pI of 6.3. Homology modeling of CsNDPK1 shows that the presented tea NDPK1 also contains several motifs, binding and catalytic sites which are highly conserved among other NDPKs. Docking studies of CsNDPK1 with its substrates (NTPs) are discussed in detail. In summary, we describe a reliable model of CsNDPK1 that can be used in structure-based protein?Cprotein interaction studies for identifying its potential role in intracellular communication and its physiological significance in tea.