Establishing the occurrence of major and minor glucosinolates in Brassicaceae by LC-ESI-hybrid linear ion-trap and Fourier-transform ion cyclotron resonance mass spectrometry

Glucosinolates (GLSs) are sulfur-rich plant secondary metabolites which occur in a variety of cruciferous vegetables and among various classes of them, genus Brassica exhibits a rich family of these phytochemicals at high, medium and low abundances. Liquid chromatography (LC) with electrospray ionization in negative ion mode (ESI-) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS) was employed for the selective and sensitive determination of intact GLSs in crude sample extracts of broccoli (Brassica oleracea L. Var. italica), cauliflower (B. oleracea L. Var. Botrytis) and rocket salad (Eruca sativa L.) with a wide range of contents. When LTQ and FTICR mass analyzers are compared, the magnitude of the limit of detection was ca. 5/6-fold lower with the FTICR MS. In addition, the separation and detection by LC-ESI-FTICR MS provides a highly selective assay platform for unambiguous identification of GLSs, which can be extended to lower abundance (minor) GLSs without significant interferences of other compounds in the sample extracts. The analysis of Brassicaceae species emphasized the presence of eight minor GLSs, viz. 1-methylpropyl-GLS, 2-methylpropyl-GLS, 2-methylbutyl-GLS, 3-methylbutyl-GLS, n-pentyl-GLS, 3-methylpentyl-GLS, 4-methylpentyl-GLS and n-hexyl-GLS. The occurrence of these GLSs belonging to the saturated aliphatic side chain families C(4), C(5) and C(6), presumably formed by chain elongation of leucine, homoleucine and dihomoleucine as primary amino acid precursors, is described. Based on their retention behavior and tandem MS spectra, all these minor compounds occurring in plant extracts of B. oleracea L. Var. italica, B. oleracea L. Var. Botrytis and E. sativa L. were tentatively identified.     

Separation and identification of mouse brain tissue microproteins using top‐down method with high resolution nanocapillary liquid chromatography mass spectrometry

Microproteins and endogenous peptides in the brain contain important substances that have critical roles in diverse biological processes, contributing to signal transduction and intercellular signaling. However, variability in their physical or chemical characteristics, such as molecule size, hydrophobicity, and charge states, complicate the simultaneous analysis of these compounds, although this would be highly beneficial for the field of neuroscience research. Here, we present a top‐down analytical method for simultaneous analysis of microproteins and endogenous peptides using high‐resolution nanocapillary LC‐MS/MS. This method is detergent‐free and digestion‐free, which allows for extracting and preserving intact microproteins and peptides for direct LC‐MS analysis. Both higher energy collision dissociation and electron‐transfer dissociation fragmentations were used in the LC‐MS analysis to increase the identification rate, and bioinformatics tools ProteinGoggle and PEAKS Studio software were utilized for database search. In total, we identified 471 microproteins containing 736 proteoforms, including brain‐derived neurotrophic factor and a number of fibroblast growth factors. In addition, we identified 599 peptides containing 151 known or potential neuropeptides such as somatostatin‐28 and neuropeptide Y. Our approach bridges the gap for the characterization of brain microproteins and peptides, which permits quantification of a diversity of signaling molecules for biomarker discovery or therapy diagnosis in the future.     

Characterization of the biosynthesis in vivo of α-aminoadipyl-cysteinyl-valine inPenicillium chrysogenum

Summary The parameters affecting the formation in vivo of -aminoadipyl-cysteinyl-valine (ACV), an intermediate in penicillin biosynthesis, have been established in low- and high-penicillin producing strains ofPenicillium chrysogenum. ACV was found both in cell extracts and in the culture broth filtrates. (¹⁴C)valine, -(¹⁴C)aminoadipic acid and (¹⁴C)cysteine were efficiently incorporated into ACV. Formation of ACV was stimulated by phenylacetic acid when added during the growth of the culture. ACV biosynthesis was enhanced when protein synthesis was blocked with cycloheximide or anisomicin. The ACV-synthesising activity of the culture increased between 24 and 48 h of the culture preceeding penicillin biosynthesis, and remained constant thereafter. A decay of ACV-forming activity was observed when de novo protein synthesis was inhibited with cycloheximide. The apparent half-life of the ACV-synthesising enzyme system was 2.5 h.     

A global review and meta-analysis of applications of the freshwater Fish Invasiveness Screening Kit

Reviews in Fish Biology and Fisheries - The freshwater Fish Invasiveness Screening Kit (FISK) has been applied in 35 risk assessment areas in 45 countries across the six inhabited continents (11...     

The multiple forms of bovine seminal ribonuclease: Structure and stability of a C-terminal swapped dimer

Bovine seminal ribonuclease (BS-RNase) acquires an interesting anti-tumor activity associated with the swapping on the N-terminal. The first direct experimental evidence on the formation of a C-terminal swapped dimer (C-dimer) obtained from the monomeric derivative of BS-RNase, although under non-native conditions, is here reported. The X-ray model of this dimer reveals a quaternary structure different from that of the C-dimer of RNase A, due to the presence of three mutations in the hinge peptide 111–116. The mutations increase the hinge peptide flexibility and decrease the stability of the C-dimer against dissociation. The biological implications of the structural data are also discussed.     

Design,synthesis, and antiprotozoal evaluation of new 2,4-bis[(substituted-aminomethyl)phenyl]quinoline, 1,3-bis[(substituted-aminomethyl)phenyl]isoquinoline and 2,4-bis[(substituted-aminomethyl)phenyl]quinazoline derivatives

Abstract

A series of new 2,4-bis[(substituted-aminomethyl)phenyl]quinoline, 1,3-bis[(substituted-aminomethyl)phenyl]isoquinoline, and 2,4-bis[(substituted-aminomethyl)phenyl]quinazoline derivatives was designed, synthesised, and evaluated in?vitro against three protozoan parasites (Plasmodium falciparum, Leishmania donovani, and Trypanosoma brucei brucei). Biological results showed antiprotozoal activity with IC₅₀ values in the µM range. In addition, the in?vitro cytotoxicity of these original molecules was assessed with human HepG2 cells. The quinoline 1c was identified as the most potent antimalarial candidate with a ratio of cytotoxic to antiparasitic activities of 97 against the P. falciparum CQ-sensitive strain 3D7. The quinazoline 3h was also identified as the most potent trypanosomal candidate with a selectivity index (SI) of 43 on T. brucei brucei strain. Moreover, as the telomeres of the parasites P. falciparum and Trypanosoma are possible targets of this kind of nitrogen heterocyclic compounds, we have also investigated stabilisation of the Plasmodium and Trypanosoma telomeric G-quadruplexes by our best compounds through FRET melting assays.     

Antifungal effect of different methyl and propyl paraben mixtures on the treatment of paper biodeterioration

With many important artistic works and documents made of paper, and thus susceptible to biodeterioration by fungi, research is required in an effort to replace toxic chemical products with other more benign ones. In this work the antifungal effect of methyl and propyl paraben mixtures at different concentrations was evaluated. The fungi used in the experiments were a Cladosporium species and Penicillium corylophilum, both of which are well known as paper-biodeteriorating fungi. The results demonstrate that a mixture of 0.5% methyl paraben and 1% propyl paraben, in 85% ethanolic solution, is the lowest concentration necessary to provide an efficient antifungal action. A deacidification agent, 5% calcium propionate, was added to this mixture to produce a multi-purpose formulation to treat acidification and fungal contamination of paper documents. Tests carried out on paper samples before and after application of this mixture showed only a minor increase in yellowing and a slight decrease in tensile strength, while substantially raising the pH, and thus the alkaline reserve, and also a slight increase in the percentage of deformation.     

Design, synthesis, biophysical and biological studies of trisubstituted naphthalimides as G-quadruplex ligands

A series of trisubstituted naphthalimides have been synthesized and evaluated as telomeric G-quadruplex ligands by biophysical methods. Affinity for telomeric G-quadruplex AGGG(TTAGGG)(3) binding was first screened by fluorescence titrations. Subsequently, the interaction of the telomeric G-quadruplex with compounds showing the best affinity has been studied by isothermal titration calorimetry and UV-melting experiments. The two best compounds of the series tightly bind the telomeric quadruplex with a 2:1 drug/DNA stoichiometry. These derivatives have been further evaluated for their ability to inhibit telomerase by a TRAP assay and their pharmacological properties by treating melanoma (M14) and human lung cancer (A549) cell lines with increasing drug concentrations. A dose-dependent inhibition of cell proliferation was observed for all cellular lines during short-term treatment.