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Frontiers in Chemistry

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https://www.readbyqxmd.com/read/28503547/theoretically-guided-analytical-method-development-and-validation-for-the-estimation-of-rifampicin-in-a-mixture-of-isoniazid-and-pyrazinamide-by-uv-spectrophotometer
#1
Mohammad F Khan, Shamima A Rita, Md Shahidulla Kayser, Md Shariful Islam, Sharmeen Asad, Ridwan Bin Rashid, Md Abdul Bari, Muhammed M Rahman, D A Anwar Al Aman, Nurul I Setu, Rebecca Banoo, Mohammad A Rashid
A simple, rapid, economic, accurate, and precise method for the estimation of rifampicin in a mixture of isoniazid and pyrazinamide by UV spectrophotometeric technique (guided by the theoretical investigation of physicochemical properties) was developed and validated. Theoretical investigations revealed that isoniazid and pyrazinamide both were freely soluble in water and slightly soluble in ethyl acetate whereas rifampicin was practically insoluble in water but freely soluble in ethyl acetate. This indicates that ethyl acetate is an effective solvent for the extraction of rifampicin from a water mixture of isoniazid and pyrazinamide...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28503546/computational-tool-for-fast-in-silico-evaluation-of-herg-k-channel-affinity
#2
Giulia Chemi, Sandra Gemma, Giuseppe Campiani, Simone Brogi, Stefania Butini, Margherita Brindisi
The development of a novel comprehensive approach for the prediction of hERG activity is herein presented. Software Phase has been used to derive a 3D-QSAR model, employing as alignment rule a common pharmacophore built on a subset of 22 highly active compounds (threshold Ki: 50 nM) against hERG K(+) channel. Five features comprised the pharmacophore: two aromatic rings (R1 and R2), one hydrogen-bond acceptor (A), one hydrophobic site (H), and one positive ionizable function (P). The sequential 3D-QSAR model developed with a set of 421 compounds (randomly divided in training and test set) yielded a test set (Q(2)) = 0...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28497036/reversed-phase-hplc-dad-profiling-of-carotenoids-chlorophylls-and-phenolic-compounds-in-adiantum-capillus-veneris-leaves
#3
Alam Zeb, Fareed Ullah
Adiantum capillus-veneris is important endangered fern species with several medicinal properties. In this study, the leaves samples were extracted and separated using reversed phase HPLC with DAD for carotenoids, chlorophylls and phenolic compounds. Separation of carotenoids and chlorophylls were carried out using a tertiary gradient system of water, MTBE and methanol-water, while a binary gradient system of methanol-water-acetic acid was used for phenolic profiling. Results revealed eight carotenoids, four pheophytins, and two chlorophylls...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28487854/non-fused-phospholes-as-fluorescent-probes-for-imaging-of-lipid-droplets-in-living-cells
#4
Elisabet Öberg, Hanna Appelqvist, K Peter R Nilsson
Molecular tools for fluorescent imaging of specific compartments in cells are essential for understanding the function and activity of cells. Here, we report the synthesis of a series of pyridyl- and thienyl-substituted phospholes and the evaluation of these dyes for fluorescent imaging of cells. The thienyl-substituted phospholes proved to be successful for staining of cultured normal and malignant cells due to their fluorescent properties and low toxicity. Co-staining experiments demonstrated that these probes target lipid droplets, which are, lipid-storage organelles found in the cytosol of nearly all cell types...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28487853/promising-approaches-to-optimize-the-biological-properties-of-the-antimicrobial-peptide-esculentin-1a-1-21-nh2-amino-acids-substitution-and-conjugation-to-nanoparticles
#5
REVIEW
Bruno Casciaro, Floriana Cappiello, Mauro Cacciafesta, Maria Luisa Mangoni
Antimicrobial peptides (AMPs) represent an interesting class of molecules with expanding biological properties which make them a viable alternative for the development of future antibiotic drugs. However, for this purpose, some limitations must be overcome: (i) the poor biostability due to enzymatic degradation; (ii) the cytotoxicity at concentrations slightly higher than the therapeutic dosages; and (iii) the inefficient delivery to the target site at effective concentrations. Recently, a derivative of the frog skin AMP esculentin-1a, named esculentin-1a(1-21)NH2, [Esc(1-21): GIFSKLAGKKIKNLLISGLKG-NH2] has been found to have a potent activity against the Gram-negative bacterium Pseudomonas aeruginosa; a slightly weaker activity against Gram-positive bacteria and interesting immunomodulatory properties...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28447030/screening-and-optimizing-antimicrobial-peptides-by-using-spot-synthesis
#6
REVIEW
Paula M López-Pérez, Elizabeth Grimsey, Luc Bourne, Ralf Mikut, Kai Hilpert
Peptide arrays on cellulose are a powerful tool to investigate peptide interactions with a number of different molecules, for examples antibodies, receptors or enzymes. Such peptide arrays can also be used to study interactions with whole cells. In this review, we focus on the interaction of small antimicrobial peptides with bacteria. Antimicrobial peptides (AMPs) can kill multidrug-resistant (MDR) human pathogenic bacteria and therefore could be next generation antibiotics targeting MDR bacteria. We describe the screen and the result of different optimization strategies of peptides cleaved from the membrane...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28443279/analogs-of-the-frog-skin-antimicrobial-peptide-temporin-1tb-exhibit-a-wider-spectrum-of-activity-and-a-stronger-antibiofilm-potential-as-compared-to-the-parental-peptide
#7
Lucia Grassi, Giuseppantonio Maisetta, Giuseppe Maccari, Semih Esin, Giovanna Batoni
The frog skin-derived peptide Temporin 1Tb (TB) has gained increasing attention as novel antimicrobial agent for the treatment of antibiotic-resistant and/or biofilm-mediated infections. Nevertheless, such a peptide possesses a preferential spectrum of action against Gram-positive bacteria. In order to improve the therapeutic potential of TB, the present study evaluated the antibacterial and antibiofilm activities of two TB analogs against medically relevant bacterial species. Of the two analogs, TB_KKG6A has been previously described in the literature, while TB_L1FK is a new analog designed by us through statistical-based computational strategies...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28439515/endogenous-retroviruses-with-us-and-against-us
#8
REVIEW
Thomas J Meyer, Jimi L Rosenkrantz, Lucia Carbone, Shawn L Chavez
Mammalian genomes are scattered with thousands of copies of endogenous retroviruses (ERVs), mobile genetic elements that are relics of ancient retroviral infections. After inserting copies into the germ line of a host, most ERVs accumulate mutations that prevent the normal assembly of infectious viral particles, becoming trapped in host genomes and unable to leave to infect other cells. While most copies of ERVs are inactive, some are transcribed and encode the proteins needed to generate new insertions at novel loci...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28424769/folates-in-plants-research-advances-and-progress-in-crop-biofortification
#9
REVIEW
Vera Gorelova, Lars Ambach, Fabrice Rébeillé, Christophe Stove, Dominique Van Der Straeten
Folates, also known as B9 vitamins, serve as donors and acceptors in one-carbon (C1) transfer reactions. The latter are involved in synthesis of many important biomolecules, such as amino acids, nucleic acids and vitamin B5. Folates also play a central role in the methyl cycle that provides one-carbon groups for methylation reactions. The important functions fulfilled by folates make them essential in all living organisms. Plants, being able to synthesize folates de novo, serve as an excellent dietary source of folates for animals that lack the respective biosynthetic pathway...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28401146/effects-of-bunch-rot-botrytis-cinerea-and-powdery-mildew-erysiphe-necator-fungal-diseases-on-wine-aroma
#10
Angela Lopez Pinar, Doris Rauhut, Ernst Ruehl, Andrea Buettner
This study aimed to characterize the effects of bunch rot and powdery mildew on the primary quality parameter of wine, the aroma. The influence of these fungal diseases was studied by comparative Aroma Extract Dilution Analyses (AEDA) and sensory tests. The effect of bunch rot was investigated on three grape varieties, namely White Riesling, Red Riesling and Gewürztraminer and that of powdery mildew on the hybrid Gm 8622-3; thereby, samples were selected that showed pronounced cases of infection to elaborate potential currently unknown effects...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28401145/porous-and-magnetic-molecularly-imprinted-polymers-via-pickering-high-internal-phase-emulsions-polymerization-for-selective-adsorption-of-%C3%AE-cyhalothrin
#11
Yunlong Wu, Yue Ma, Jianming Pan, Runxing Gu, Jialu Luo
A novel macroporous magnetic molecularly imprinted polymer (MMIPs) of was prepared by W/O Pickering (high internal phase emulsions) HIPEs polymerization, and then it was adopted as adsorbent for selective adsorption of λ-cyhalothrin (LC). In static conditions, adsorption capacity of LC increased rapidly in the first 60 min and reached to equilibrium in ~2.0 h. Excellent conformity of the second-order model confirmed the chemical nature of the interaction between the LC and imprinted sites. The fitting adsorption isotherm was a Langmuir type, and the maximum monolayer adsorption capacity at 298 K was 404...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28401144/insights-into-the-activity-change-of-spore-photoproduct-lyase-induced-by-mutations-at-a-peripheral-glycine-residue
#12
Linlin Yang, Lei Li
UV radiation triggers the formation of 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP), in the genomic DNA of bacterial endospores. These SPs, if not repaired in time, may lead to genome instability and cell death. SP is mainly repaired by spore photoproduct lyase (SPL) during spore outgrowth via an unprecedented protein-harbored radical transfer pathway that is composed of at least a cysteine and two tyrosine residues. This mechanism is consistent with the recently solved SPL structure that shows all three residues are located in proximity and thus able to participate in the radical transfer process during the enzyme catalysis...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28393065/why-aromaticity-is-a-suspicious-concept-why
#13
Miquel Solà
No abstract text is available yet for this article.
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28386537/revealing-a-novel-otubain-like-enzyme-from-leishmania-infantum-with-deubiquitinating-activity-toward-k48-linked-substrate
#14
Clênia S Azevedo, Bruna C Guido, Jhonata L Pereira, Diego O Nolasco, Rafael Corrêa, Kelly G Magalhães, Flávia N Motta, Jaime M Santana, Philippe Grellier, Izabela M D Bastos
Deubiquitinating enzymes (DUBs) play an important role in regulating a variety of eukaryotic processes. In this context, exploring the role of deubiquitination in Leishmania infantum could be a promising alternative to search new therapeutic targets for leishmaniasis. Here we present the first characterization of a DUB from L. infantum, otubain (OtuLi), and its localization within parasite. The recombinant OtuLi (rOtuLi) showed improved activity on lysine 48 (K48)-linked over K63-linked tetra-ubiquitin (Ub) and site-directed mutations on amino acids close to the catalytic site (F82) or involved in Ub interaction (L265 and F182) caused structural changes as shown by molecular dynamics, resulting in a reduction or loss of enzyme activity, respectively...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28382299/effects-of-high-temperature-frying-of-spinach-leaves-in-sunflower-oil-on-carotenoids-chlorophylls-and-tocopherol-composition
#15
Alam Zeb, Parveen Nisar
Spinach is one of the highly consumed vegetable, with significant nutritional, and beneficial properties. This study revealed for the first time, the effects of high temperature frying on the carotenoids, chlorophylls, and tocopherol contents of spinach leaves. Spinach leaves were thermally processed in the sunflower oil for 15, 30, 45, and 60 min at 250°C. Reversed phase HPLC-DAD results revealed a total of eight carotenoids, four chlorophylls and α-tocopherol in the spinach leaves. Lutein, neoxanthin, violaxanthin, and β-carotene-5,6-epoxide were the major carotenoids, while chlorophyll a and b' were present in higher amounts...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28377919/tb-3-cleavage-assays-reveal-specific-mg-2-binding-sites-necessary-to-pre-fold-the-btub-riboswitch-for-adocbl-binding
#16
Pallavi K Choudhary, Sofia Gallo, Roland K O Sigel
Riboswitches are RNA elements that bind specific metabolites in order to regulate the gene expression involved in controlling the cellular concentration of the respective molecule or ion. Ligand recognition is mostly facilitated by Mg(2+) mediated pre-organization of the riboswitch to an active tertiary fold. To predict these specific Mg(2+) induced tertiary interactions of the btuB riboswitch from E. coli, we here report Mg(2+) binding pockets in its aptameric part in both, the ligand-free and the ligand-bound form...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28373972/in-vivo-efficacy-and-pharmacokinetics-of-optimized-apidaecin-analogs
#17
Rico Schmidt, Daniel Knappe, Elisabeth Wende, Eszter Ostorházi, Ralf Hoffmann
Proline-rich antimicrobial peptides (PrAMPs) represent promising alternative therapeutic options for the treatment of multidrug-resistant bacterial infections. PrAMPs are predominantly active against Gram-negative bacteria by inhibiting protein expression via at least two different modes of action, i.e., blocking the ribosomal exit tunnel of 70S ribosomes (oncocin-type binding) or inhibiting the assembly of the 50S ribosomal subunit (apidaecin-type binding). The in vivo efficacy and favorable biodistribution of oncocins confirmed the therapeutic potential of short PrAMPs for the first time, whereas the in vivo evaluation of apidaecins is still limited despite the promising efficacy of apidaecin-analog Api88 in an intraperitoneal murine infection model...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28361051/on-the-role-of-additional-4fe-4s-clusters-with-a-free-coordination-site-in-radical-sam-enzymes
#18
REVIEW
Etienne Mulliez, Victor Duarte, Simon Arragain, Marc Fontecave, Mohamed Atta
The canonical CysXXXCysXXCys motif is the hallmark of the Radical-SAM superfamily. This motif is responsible for the ligation of a [4Fe-4S] cluster containing a free coordination site available for SAM binding. The five enzymes MoaA, TYW1, MiaB, RimO and LipA contain in addition a second [4Fe-4S] cluster itself bound to three other cysteines and thus also displaying a potentially free coordination site. This review article summarizes recent important achievements obtained on these five enzymes with the main focus to delineate the role of this additional [4Fe-4S] cluster in catalysis...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28361050/conceptual-dft-descriptors-of-amino-acids-with-potential-corrosion-inhibition-properties-calculated-with-the-latest-minnesota-density-functionals
#19
Juan Frau, Daniel Glossman-Mitnik
Amino acids and peptides have the potential to perform as corrosion inhibitors. The chemical reactivity descriptors that arise from Conceptual DFT for the twenty natural amino acids have been calculated by using the latest Minnesota family of density functionals. In order to verify the validity of the calculation of the descriptors directly from the HOMO and LUMO, a comparison has been performed with those obtained through ΔSCF results. Moreover, the active sites for nucleophilic and electrophilic attacks have been identified through Fukui function indices, the dual descriptor Δf(r) and the electrophilic and nucleophilic Parr functions...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28344971/how-to-train-a-cell-cutting-edge-molecular-tools
#20
REVIEW
Jakub Czapiński, Michał Kiełbus, Joanna Kałafut, Michał Kos, Andrzej Stepulak, Adolfo Rivero-Müller
In biological systems, the formation of molecular complexes is the currency for all cellular processes. Traditionally, functional experimentation was targeted to single molecular players in order to understand its effects in a cell or animal phenotype. In the last few years, we have been experiencing rapid progress in the development of ground-breaking molecular biology tools that affect the metabolic, structural, morphological, and (epi)genetic instructions of cells by chemical, optical (optogenetic) and mechanical inputs...
2017: Frontiers in Chemistry
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