Biomedical Chemistry: Research and Methods

Methods for Determining Individual Amino Acids in Biological Fluids

E.A. Sarf — 2025-03-28

Determination of the amino acid composition of biological fluids is of great diagnostic importance. Commonly accepted methods of amino acid analysis include chromatography, electrophoresis and mass-spectrometry. However, for research purposes, to solve specific problems, it is often necessary to determine not the complete amino acid profile, but the concentration of individual amino acids. This review presents literature data analysis on methods used for determining individual amino acids in biological fluids. It is shown that amino acids can be determined by spectrophotometric, electrochemical methods, as well as using a wide range of biosensors, are the detection limit is basically comparable to chromatographic methods of analysis.

The Influence of Adjuvants on Antigenic Properties of Peptide Constructs Composed of Hepatitis C Virus Envelope Protein E2 Fragments

E.A. Egorova — 2025-02-10

Effectiveness of the immune response in the form of the production of specific antibodies against immunogenic peptide constructs composed of conservative fragments of the hepatitis C virus envelope protein E2 depended on the adjuvants and carriers used in their preparations. The most effective formation of specific antibodies was observed in response to the injection of peptide constructs containing B- and T-epitopes of the E2 protein conjugated with a carrier with adjuvant properties, Immunomax. Antibodies obtained in response to immunization with conjugates of peptide constructs with Immunomax bound both hepatitis C virus envelope protein E2 and the heterodimer of envelope proteins E1E2.

Study of the Adjuvant Properties of Chitosan in Complex with Recombinant Outer Membrane Protein F and Recombinant Toxoid Pseudomonas Aeruginosa

A.A. Kaloshin — 2025-03-28

The aim of the study was to investigate adjuvant properties of chitosan in comparison with aluminum hydroxide during immunization with recombinant proteins of Pseudomonas aeruginosa. We used recombinant outer membrane protein F (OprF) and recombinant toxoid of P. aeruginosa, to which 0.5% chitosan preparation dissolved in glutamic acid with pH 5.0 or aluminum hydroxide gel were added. The ratios of aluminum hydroxide to protein of 3:1 and 1:1 were tested, and chitosan was added at 100 μg and 50 μg for one immunizing dose. The resulting preparations were administered to mice intraperitoneally twice with a two-week interval, and then two weeks later the animals were infected intraperitoneally with P. aeruginosa (PA-103). It was shown that double administration of the recombinant OprF protein at a dose of 25 μg and recombinant toxoid at a dose of 50 μg with both aluminum hydroxide and chitosan contributed to the development of equivalent protective properties. With the complex introduction of two recombinant proteins, an increase in protective properties was observed using both adjuvants. The possibility of using antigens without adjuvant and reducing their immunizing dose during booster immunization was investigated. It turned out that a two-fold reduction in the immunizing dose did not reduce the protective effect upon repeated administration, and in the case of chitosan, an increase in the immune response was observed during booster immunization with recombinant antigens without an adjuvant. Thus, for the recombinant proteins of P. aeruginosa, the adjuvant properties of chitosan were revealed. They are not inferior in the induction of protective properties to aluminum hydroxide.

Novel Phosphonium Salt Derivatives Induce DNA Damage and Apoptosis in Cervical Cancer Cells

A.P. Lyubina — 2025-03-28

This study demonstrates that (Z)-(2-(2-hydroxy-5-chlorophenyl)-2-phenylethenyl)alkyldiphenylphosphonium chlorides exhibit high antitumour activity, comparable to that of the reference drug doxorubicin. The phosphonium salts exhibited reduced toxicity towards conditionally normal cell lines in the majority of cases. The mechanism of action of compound PP8, which contains an octyl radical at the phosphorus atom, on the model cell line M-HeLa included partial cell cycle arrest in the G1 phase, an increased generation of reactive oxygen species, and an induction of mitochondrial apoptosis. These experimental data are supported by the elevated levels of p53, p21, H2A.X and caspase-9 proteins detected by multiplex analysis. The results indicated the occurrence of double-strand DNA breaks under the influence of the studied compound. Therefore, additional structural modifications to enhance the selectivity of the studied compounds will provide a basis for the development of novel effective antitumour agents.

Detection of the Kidney Tumor Suppressor DUSP9 in the Urine of Healthy Donors

A.G. Polischouk — 2025-03-28

The DUSP9/MKP-4 belongs to the family of bispecific protein phosphatases that negatively regulate MAP kinases (ERK, p38 and JNK). The expression of DUSP9 is significantly (20-80-fold) reduced compared to normal tissue in 95% of the studied human renal cell carcinoma samples. These and other scientific data indicate that DUSP9 is an attractive target for the use in clinical practice. However, so far, postoperative tumor biopsy samples remain the only source of clinical material in which expression of DUSP9 has been studied. This significantly limits the possibilities of using DUSP9 for clinical purposes. The purpose of this work was to find out whether it would be possible to detect DUSP9 in human urine. In the study we used human kidney carcinoma ACHN cells transfected with a vector, expressing DUSP9 and urine samples from 3 healthy volunteers. DUSP9 protein was detected by the Western blot method in precipitates obtained by centrifugation. We have shown that the DUSP9 protein is present in the pellet of the urine fraction obtained by low-speed centrifugation (10000 g). It is also present in the fraction of extracellular vesicles enriched with exosomes. The obtained result indicates that the analysis of DUSP9 expression is possible using a liquid biopsy, which, in turn, can significantly expand the applicability of this analysis for clinical purposes.