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1
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Detection and sequencing of new cyclic peptides from linseed by electrospray ionization mass spectrometry.

100%
Stefanowicz P.
|
2001
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vol. 48
|
issue 4
1125-1129
EN
Extract of Linum usitatissimum seeds was analyzed by ESI-MS and ESI-MS/MS. The analysis confirms the presence of previously reported cyclolinopeptides: CLA (c(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val) and CLB (c(Pro-Pro-Phe-Phe-Val-Ile-Met-Ile-Leu)). Cyclolinopeptides CLD and CLE, which contain methionine oxide, were detected in small quantities only. These peptides likely result from the oxidation of their precursors, not reported previously: CLD' (c(Pro-Phe-Phe-Trp-Ile-Met-Leu-Leu)) and CLE' (c(Pro-Leu-Phe-Ile-Met-Leu-Val-Phe)), present at higher concentrations in unoxidized extract. Two new cyclic octapeptides: CLF (c(Pro-Phe-Phe-Trp-Val-Met-Leu-Met)) and CLG (c(Pro-Phe-Phe-Trp-Ile-Met-Leu-Met)) were detected and their sequences were proposed on the basis of CID experiments and similarity with those of CLD'.
2
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Metabolism of bradykinin in aorta of hypertensive rats

80%
Bujak-Giżycka B., Olszanecki R., Madej J., Suski M., Gębska A., Korbut R.
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2011
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vol. 58
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issue 2
199-202
EN
Alterations in the formation and metabolism of bradykinin (Bk) are hypothesized to play a role in the pathophysiology of hypertension, atherosclerosis and vascular complications of diabetes. However, despite its prominent role in cardiovascular regulation, studies on bradykinin have been limited by various difficulties in accurate measurements of this peptide in biological samples. In this study, using the LC-ESI-MS method we estimated the conversion of exogenous Bk to its main metabolites - Bk-(1-5) and Bk-(1-7) - in endothelial cell culture and in fragments of aorta of normotensive (WKY) and hypertensive rats (SHR). The effects of angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) inhibitors were more pronounced in SHR: perindoprilat inhibited Bk-(1-5) formation by 49 % and 76 % in WKY and SHR rats, respectively, and tiorphan tended to decrease formation of Bk-(1-5) in both groups of animals. The degradation of bradykinin and generation of both metabolites were significantly higher in the aorta of SHR rats than in WKY controls. Our results show that even in relatively early hypertension (in 4-month old SHR rats) inactivation of Bk by aorta wall is enhanced.
3
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FAPA mass spectrometry of hydroxychalcones. Comparative studies with classical methods of ionization

80%
Smoluch M., Bartkowiak G., Reszke E., Lechowicz W., Silberring J., Schroeder G.
Current Issues in Pharmacy and Medical Sciences
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2014
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vol. 27
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issue 1
27-31
EN
In this paper we are focused on analysis of hydroxychalcones, i.e. 2’-hydroxychalcone, 3’-hydroxychalcone and 4’-hydroxychalcone, by the Flowing Atmospheric Pressure Afterglow mass spectrometry (FAPA-MS), and on comparison of the obtained data with other classical methods including ESI-MS, APCI, MALDI, and GC/EI-MS. The paper is presenting fragmentation pathways of both positive-, and negative hydroxychalcone ions. Tested compounds were characterized by comparison of the results (signals m/z and relative intensities) from the five mass spectrometry techniques, showing very good utility of FAPA method for fast and easy analysis of the low molecular weight compounds. Moreover, FAPA does not require a time-consuming derivatization, nor search for a suitable solvent or matrix, often incompatible with various ion sources.
4
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Temperature stability of mercury compounds in solid substrates

70%
Sedlar M., Pavlin M., Popovič A., Horvat M.
Open Chemistry
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2015
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vol. 13
|
issue 1
EN
The major aim of the newly adopted Mercury Convention is to reduce global mercury (Hg) emissions to the environment. In high temperature industrial processes, including coal combustion, Hg compounds present as impurities in solid materials are decomposed and evaporated leading to the emission of Hg to the atmosphere. The behaviour of different Hg compounds and their mixtures during heating have been the subject of numerous studies, and is the topic of the present work. Controlled heating can be used to fractionate Hg compounds in solid substrates, offering the possibility of identification and quantification of Hg compounds. In the attempt to develop a method for temperature fractionation of Hg, experiments were conducted with pure Hg compounds, and the compounds mixed with different substrates (SiO2 and CaSO4 • 2H2O), for calibration purposes. Detection was performed by two methods, namely Cold Vapour Atomic Absorption Spectrometry (CV AAS) with Zeeman background correction, and Nier-type Mass Spectrometry with a Knudsen cell (MS). Further investigation is in process.
5
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Liquid chromatographic determination of glyphosate and aminomethylphosphonic acid residues in rapeseed with MS/MS detection or derivatization/fluorescence detection

70%
Kaczyński P., Łozowicka B.
Open Chemistry
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2015
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vol. 13
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issue 1
EN
Glyphosate and AMPA determinations in rapeseed extracts by (a) liquid chromatography with triple quadrupole MS detection (LC-MS/MS), or (b) liquid chromatography with post-column OPA derivatization and fluorescence detection (LC-FLD) were developed. Mean recoveries for glyphosate and AMPA were (a) 88.8–95.0% and 82.1–86.1%, and (b) 70.8–74.1% and 62.4–72.6%. RSD were below (a) 11% and (b) 22%. Correlation coefficients were above 0.997 for both methods. LOD were 0.01 mg kg-1 for (a) and 0.05 mg kg-1 for (b). Both methods are simple and efficient for routine analysis of glyphosate and AMPA in a fatty matrix.
6
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Content available

COCAINE CONSUMPTION IN THE CITY OF MURCIA (SOUTHEAST OF SPAIN) ESTIMATED BY WASTEWATER ANALYSIS: APPLYING AN ACCURATE AND VALID TOOL TO OBTAIN OBJECTIVE DATA FOR DRUG ABUSE.

70%
Navarro-Zaragoza J., Fernández-López L., Caravaca F., Falcón M., Luna A.
Acta Poloniae Pharmaceutica - Drug Research
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2019
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vol. 76
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issue 1
137-145
EN
Cocaine consumption is one of the most relevant public health issues in America and Europe. There are different methods to estimate cocaine consumption, with different levels of accuracy. Although surveys is one of the most employed methods, it usually underestimates cocaine consumption. Recent studies have validated the use of wastewater analysis as the method that would provide more accurate results, as it is based on the analysis of residues of illicit drugs and their metabolites that are excreted by human flow through wastewater treatment plants. This study aims to estimate cocaine consumption in the southeast of Spain by wastewater analysis. Samples were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). According to this analysis, cocaine consumption has been estimated at 410,6 milligrams per day and per 1000 inhabitants, a higher result than that obtained at other European cities of similar size. Highest consumption occurs during the weekend, which is consistent with cocaine being categorized as a recreational drug. The results of this analysis show that cocaine use is an increasing public health and economic problem. Finally, wastewater analysis offers different options to estimate its use at this region of Spain.
7
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Mass spectrometric analysis of head-to-tail connected cyclic peptides.

70%
Macht M., Pelzing M., Palloch P., Sauerland V., Volz J.
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2001
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vol. 48
|
issue 4
1109-1112
EN
Tandem mass spectrometry is an extremly useful tool for high sensitive sequence identification of peptides. In the case of cyclic peptides fragmentation can easily be performed for sequence analysis. However, analysis is usually tedious due to the lack of a defined beginning and end of the sequence. Since cyclic peptides are a highly interesting class of compounds especially for the pharmaceutical industry, ways have to be found to identify their structures. In this work we demonstrate how software and dedicated analytical strategies can be used for detailed analysis of these substances.
8
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Application of the TG-MS system in studying sewage sludge pyrolysis and gasification

70%
Bedyk T., Nowicki L., Stolarek P., Ledakowicz S.
Polish Journal of Chemical Technology
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2008
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vol. 10
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issue 1
1-5
EN
A method of monitoring sewage sludge pyrolysis and gasification was proposed. Samples of sludge were pyrolysed in Ar and gasified in CO2 in a thermobalance. The evolved gases were analysed on the calibrated MS, the samples of sludge and solid residues at different stages of the processes were subjected to elemental analysis. The identification and the quantitative characterisation of chemical reactions were performed, based on the DTG and MS profiles.
9
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Content available

Ionizing radiation affects profile of serum metabolites: increased level of 3-hydroxybutyric acid in serum of cancer patients treated with radiotherapy

70%
Roś-Mazurczyk M., Wojakowska A., Marczak Ł., Polański K., Pietrowska M., Jelonek K., Domińczyk I., Hajduk A., Rutkowski T., Składowski K., Widłak P.
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2017
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vol. 64
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issue 1
189-193
EN
Radiotherapy causes molecular changes observed at the level of body fluids, which are potential biomarker candidates for assessment of radiation exposure. Here we analyzed radiotherapy-induced changes in a profile of small metabolites detected in sera of head and neck cancer patients using the gas chromatography coupled with mass spectrometry approach. There were about 20 compounds, including carboxylic acids, sugars, amines and amino acids, whose levels significantly differed between pre-treatment and post-treatment samples. Among metabolites upregulated by radiotherapy there was 3-hydroxybutyric acid, whose level increased about three times in post-treatment samples. Moreover, compounds affected by irradiation were associated with several metabolic pathways, including protein biosynthesis and amino acid metabolism.
10
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Content available

Domestic fowl of ducks, a source of faecal bioactive Enterococcus hirae strains

61%
Lauková A., Bino E., Ščerbová J., Lauková A., Bino E., Ščerbová J.
Polish Journal of Veterinary Sciences
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2019
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issue 3
11
Content available remote

Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry

61%
Jia C., Qi W., He Z., Yang H., Qiao B.
Open Chemistry
|
2006
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vol. 4
|
issue 2
285-298
EN
Two heptapeptides have been prepared by Fmoc methodology using Wang resin as solid support. For attachment of the first amino acid, several coupling systems were evaluated, and DIC/DMAP system could give yields of >99% and low levels of racemization. The selection of scavenger combination to deprotect side chains revealed that H2O/p-cresol was good at scavenging trityl and 1,2-ethanedithiol was highly efficient for scavenging t-butyl. Through shortening the preactivation time to 5 min, the racemization which occurred during formation of amide bonds coupled by HBTU was minimized. The crude peptides were characterized by RP-HPLC and MS, and sequenced by MS/MS to acquire reliable amino acid sequence information.
12
Publication available in full text mode
Content available

Antifungal activity of Trichoderma VOCs against Pyrenophora teres, the causal agent of barley net blotch

51%
Moya P., Girotti J. R., Toledo A. V., Noemi S. M.
Journal of Plant Protection Research
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2018
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vol. 58
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issue 1
13
Content available remote

Peptidomics to study age-related diseases: spotlight on cancer and neurodegeneration

51%
Sedić M., Pavelić K., Josić D., Kraljević Pavelić S.
Peptidomics
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2014
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vol. 1
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issue 1
EN
Peptides in human body fluids closely mirror processes of protein synthesis, processing and degradation. Since peptide levels and composition in the circulation fluctuate in close correlation with specific condition (either physiological or pathological) of an individual, comprehensive peptide analysis may unravel novel disease biomarkers or pave the way to new diagnostic approaches. Discovery of novel peptide biomarkers could facilitate drug development, as peptides can be used to monitor response to drugs, and thus help determine an optimal therapeutic dosage and assess toxic effects. In this review, we will provide a short overview of typical mass spectrometry-based peptidomics workflow, and give the examples from current literature of how peptidomics studies could potentially improve detection and treatment of cancer and neurodegenerative diseases, the latter including Alzheimer’s and Creutzfeldt-Jakob disease.
14
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Desorption/ionization on silicon for small molecules: a promising alternative to MALDI TOF.

51%
Kraj A., Dylag T., Gorecka-Drzazga A., Bargiel S., Dziuban J., Silberring J.
|
EN
A method has been developed for laser desorption/ionization of catecholamines from porous silicon. This methodology is particularly attractive for analysis of small molecules. MALDI TOF mass spectrometry, although a very sensitive technique, utilizes matrices that need to be mixed with the sample prior to their analysis. Each matrix produces its own background, particularly in the low-molecular mass region. Therefore, detection and identification of molecules below 400 Da can be difficult. Desorption/ionization of samples deposited on porous silicon does not require addition of a matrix, thus, spectra in the low-molecular mass region can be clearly readable. Here, we describe a method for the analysis of catecholamines. While MALDI TOF is superior for proteomics/peptidomics, desorption/ionization from porous silicon can extend the operating range of a mass spectrometer for studies on metabolomics (small organic molecules and their metabolites, such as chemical neurotransmitters, prostaglandins, steroids, etc.).
15
Content available remote

Probing protein structure by limited proteolysis.

41%
Fontana A., de Laureto P. P., Spolaore B., Frare E., Picotti P., Zambonin M.
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vol. 51
|
issue 2
299-321
EN
Limited proteolysis experiments can be successfully used to probe conformational features of proteins. In a number of studies it has been demonstrated that the sites of limited proteolysis along the polypeptide chain of a protein are characterized by enhanced backbone flexibility, implying that proteolytic probes can pinpoint the sites of local unfolding in a protein chain. Limited proteolysis was used to analyze the partly folded (molten globule) states of several proteins, such as apomyoglobin, α-lactalbumin, calcium-binding lysozymes, cytochrome c and human growth hormone. These proteins were induced to acquire the molten globule state under specific solvent conditions, such as low pH. In general, the protein conformational features deduced from limited proteolysis experiments nicely correlate with those deriving from other biophysical and spectroscopic techniques. Limited proteolysis is also most useful for isolating protein fragments that can fold autonomously and thus behave as protein domains. Moreover, the technique can be used to identify and prepare protein fragments that are able to associate into a native-like and often functional protein complex. Overall, our results underscore the utility of the limited proteolysis approach for unravelling molecular features of proteins and appear to prompt its systematic use as a simple first step in the elucidation of structure-dynamics-function relationships of a novel and rare protein, especially if available in minute amounts.
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