1.
Mass Spectrometry Differentiation between Rana arvalis Populations Based on Their Skin Peptidome Composition
Tatiana Yu. Samgina, Irina D. Vasileva, Polonca Trebse, Gregor Torkar, Alexey K. Surin, Zhaowei Meng, Roman A. Zubarev, Albert T. Lebedev*
J. Am. Soc. Mass Spectrom. 2022, 33, 1480−1491
https://doi.org/10.1021/jasms.2c00084
Skin secretion of amphibians often represents the only weapon of these species against pathogens and predators. Peptides constitute the major portion of active molecules of that weapon and may be treated as potential pharmaceuticals for future generations. The first step of their efficient use involves establishing of their primary structure, i.e., sequencing. De novo sequencing by means of mass spectrometry was applied to Rana arvalis species, collected in the spring 2021 in Central Slovenia (vicinity of Ljubljana). HPLC-ESI-HRMS/MS with Orbitrap instruments was used to establish the skin peptidome of these species and compare it with the earlier identified skin peptidome of the Moscow population of Rana arvalis. Application of CID, HCD, ETD, and EThcD enabled detecting and sequencing 18 peptides; five of them were novel and may be treated as possible biomarkers of the Ljubljana population of Rana arvalis. Interestingly, representatives of two peptide families (temporins and brevinins 2) were not found in the Moscow population. MS3 modes, first of all EThcD, demonstrated their great potential in the de novo sequencing, including extraction of the sequence information from the intact peptides with disulfide cycle (rana box) in their structure and differentiation of isomeric Leu/Ile residues. Thus, all six isomeric residues were reliably distinguished in the novel melittin-related peptide AK-23-1. In addition, another post-translational modification dealing with carbonylation of the N-terminal Gly of novel temporin AVa was established using the MS3 mode. The obtained results demonstrate the efficiency of the use of MS3 tools in proteomics/peptidomics.
2.
Mass spectrometry in de novo sequencing of the skin peptides from Arkhangelsk, Russia Rana temporaria: the variability of secreted AMPs in different populations
T.Yu. Samguina, I.D. Vasilieva, A.Yu. Kozhevnikov, Zhaowei Meng, R.A. Zubarev, A.T. Lebedev*
https://doi.org/10.1016/j.ijms.2022.116984
Amphibians are one of the oldest classes of vertebrates inhabiting the Earth. Meanwhile, the only weapon their majority possess involves exclusively peptide cocktail secreted by their skin glands in stress conditions. These peptides are considered potential pharmaceuticals of future generations as the mechanism of their interaction with pathogenic microbiota differs greatly from that of the modern antibiotics. High resolution tandem mass spectrometry showed itself as the most powerful tool to uncover the primary structure (sequence) of peptides. In the present study that analytical tool was used to establish skin peptidome of the Rana temporaria frog population from Arkhangelsk, Russia. Thirty-four peptides were sequenced while five of them turned out to be novel. The established peptidome was compared with those of studied earlier populations of Rana temporaria specie (Moscow, central Slovenian, and Italian). Temporins were proposed to be the most variable peptide family responsible for the adaptation of Rana temporaria frog to the conditions of their habitat. The EThcD MS3 method of fragmentation demonstrated its excellent ability to deal with intact disulfide-containing peptides, short peptides capable of cyclizing in conditions of MS/MS experiment, and isomeric Leu/Ile residues.
3.
Radiation-induced degradation of doxazosin: Role of reactive species, toxicity, mineralization and degradation pathways
Ivana Tartaro Bujak, Marijana Pocrni, Karlo Blazek, Krunoslav Bojanic, Polonca Trebse, Albert T. Lebedev, Nives Galic
https://doi.org/10.1016/j.jwpe.2022.103401
State-of-the-art technologies based on advanced oxidation processes (AOPs) are currently being developed for the removal of environmental pollutants such as pharmaceuticals from water matrices. Such studies are very important and should include the impact of inorganic and organic matrix on the degradation process of pollutants. One of the AOPs that is in focus of investigations nowadays, is ionizing radiation. Doxazosin (DOX) is a widely used pharmaceutical for the treatment of hypertension, which can be potentially harmful due to its occurrence in the aquatic environment. This study reports the radiation-induced degradation of DOX in aqueous solution. Removal of 10 mg L− 1 DOX reached almost 100 % at irradiation doses of 200 Gy regardless of the dose rate used. The effect of saturated solutions with N2, N2O, air and the addition of radical scavengers such as 2-PrOH and thiourea on DOX degradation was investigated. The efficiency of degradation increased in the order: thiourea < 2-PrOH < N2 < air < N2O. The effects of pH, various inorganic ions and water matrix on DOX degradation were also studied. DOX degradation was lower in underground water than in ultrapure water. Under
prolonged irradiation, mineralization of about 60 % of DOX solutions was observed based on the dissolved organic carbon (DOC) evaluation. Toxicity tests with V. fischeri luminescent bacteria showed higher toxicity of samples irradiated at 500 Gy. The main degradation products were identified using LC-HRMS and degradation
pathways were proposed. Overall, irradiation technology could be a promising technique for the removal of micropollutants, such as pharmaceuticals in real water matrices.
4.
Solving the mystery of the Chukotka stinky Gray whales
Olga V. Polyakova, Olga A. Filatova, Ivan D. Fedutin, Denis I. Litovka, Bauyrzhan Bukenov, Vyacheslav B. Artaev, Elizabeth M. Humston-Fulmer, Joe Binkley, Dmitry S. Kosyakov, Albert T. Lebedev
https://doi.org/10.1016/j.chemosphere.2023.137785
Gray whales (Eschrichtius robustus) constitute an important part of the diet of Chukotka Native population, reaching 30% of consumed food for the inland Chukchas. Over one hundred licenses for whale hunting are issued on an annual basis. After the USSR collapse natives had to hunt whales near the shore from the small boats. The problem of “stinky” whales arose immediately, as the meat of some harvested species possessed a strong medicinal/chemical odour. The hypotheses explaining the phenomenon ranged from biotoxins, to oil spills. To understand the problem, various tissues of normal and stinky Gray whales were collected in 2020-2021 and analyzed using headspace solid phase microextraction with Gas Chromatography – Mass Spectrometry. Here, we show that dozens of smelly organic compounds were identified among over 500 compounds detected in the samples. The most interesting analytes related to the off odour are bromophenols. The most probable suspect is 2,6-dibromophenol with strong iodoformic odour, perfectly matching that of the “stinky” whales. Quantitative results demonstrated its levels were up to 500-fold higher in the “stinky” whales´ tissues. The source of 2,6-dibromophenol is likely polychaetes, producing 2,6-dibromophenol and colonising near shore waters where whales feed. Therefore, the mystery of the stinky whales may be considered resolved.
5.
Chlorination of UV Filters with Antioxidant Shield in Swimming Pool Waters – Products Identification and Toxicity Assessment
Mojca Bavcon Kralj, Albert T. Lebedev, Polonca Trebše
Acta Chim. Slov. 2023, 70, 601–610. DOI: 10.17344/acsi.2023.8411
This work summarizes our research on synthesis, characterization and toxicity of selected UV-A filters and their antioxidant shield in commercial formulation – resveratrol. Benzophenone type of UV filters react under disinfection conditions with chlorine and form different mono- and dichlorinated products, while dibenzoylmethane derivatives, such as avobenzone, react with chlorine and form two main bridge chlorinated products followed by numerous chlorinated species at the advanced stages of the process. Resveratrol showed three main susceptible centers to chlorination, starting from the electrophilic addition to the double bond and continuing with the chlorination of the phenolic moieties. Several experiments conducted under different disinfection conditions (pool/sea water, addition of salts, irradiation) showed basically similar chlorination patterns with some variations in terms of product formation. The results of toxicity assessment using different test organisms (Vibrio fischeri, microalgae, daphnids) have shown different sensitivity of testing organisms to the parent UV filters in comparison with chlorinated products as well as different toxicity for specific UV filter in comparison to the others. As the closing loop of all experiments in the laboratory, an up-scaling to the real
human skin is presented.