Investigation of interactions between terpyridine ruthenium(II) complexes and serum transport proteins.

Ova disertacija se bavi ispitivanjem interakcija tri potencijalna antitumorska kompleksa Ru(II) opšte formule mer-[Ru(Cl-tpy)(N-N)Cl]Cl (Cl-tpy - 4′-hloro-2,2′:6′,2″-terpiridin; N-N - 1,2-diaminoetan (en), 1,2-diaminocikloheksan (dach) ili 2,2′-bipiridin (bipy)) sa transportnim proteinima seruma, humanim serum albuminom (HSA) i transferinom (Tf). Odabrani kompleksi Ru(II) pripadaju novoj klasi terpiridinskih kompleksa meridionalne geometrije, koji pokazuju visoku rastvorljivost u vodi. Do sada je u literaturi pokazana sposobnost ovih kompleksa da grade monofukcionalne adukte sa derivatima guanina, istiĉući njihov potencijal za vezivanje za DNK molekul. MeĊutim, interakcije sa proteinima do sada nisu ispitane. Kako se antikancerski agensi na bazi metala u organizam unose intravenozno, vezivanje kompleksa za transportne proteine seruma je izuzetno vaţno jer moţe znaĉajno uticati na njihovu biodistribuciju i efikasnost..

Investigation of interactions between terpyridine ruthenium(II) complexes and serum transport proteins.

Ova disertacija se bavi ispitivanjem interakcija tri potencijalna antitumorska kompleksa Ru(II) opšte formule mer-[Ru(Cl-tpy)(N-N)Cl]Cl (Cl-tpy - 4′-hloro-2,2′:6′,2″-terpiridin; N-N - 1,2-diaminoetan (en), 1,2-diaminocikloheksan (dach) ili 2,2′-bipiridin (bipy)) sa transportnim proteinima seruma, humanim serum albuminom (HSA) i transferinom (Tf). Odabrani kompleksi Ru(II) pripadaju novoj klasi terpiridinskih kompleksa meridionalne geometrije, koji pokazuju visoku rastvorljivost u vodi. Do sada je u literaturi pokazana sposobnost ovih kompleksa da grade monofukcionalne adukte sa derivatima guanina, istiĉući njihov potencijal za vezivanje za DNK molekul. MeĊutim, interakcije sa proteinima do sada nisu ispitane. Kako se antikancerski agensi na bazi metala u organizam unose intravenozno, vezivanje kompleksa za transportne proteine seruma je izuzetno vaţno jer moţe znaĉajno uticati na njihovu biodistribuciju i efikasnost..

Highly water-soluble ruthenium(II) terpyridine coordination compounds form stable adducts with blood-borne metal transporting proteins

Three coordination compounds of ruthenium(II), belonging to a recently synthesised series of water-soluble compounds of general formula mer- [Ru(L3)(N-N)Cl]Cl, where L3 = 4'-chloro-2, 2':6', 2″-terpyridine (Cl-tpy), N-N = ethylenediamine (en), 1, 2-diaminocyclohexane (dach) or 2, 2'-bipyridine (bpy), have shown strong binding to calf thymus DNA and moderate in vitro cytotoxicity towards cancer cell lines. Knowing that serum proteins play a crucial role in the transport and deactivation of ruthenium drugs, we have conducted a detailed study of their interactions with two major metal-transporting serum proteins, albumin and transferrin, and it is presented herein. Ruthenated protein adducts were formed with various concentrations of the three compounds and then separated from the unbound portions by ultrafiltration through 10 kDa cut- off centrifugal filter units. The stoichiometry of binding was determined using inductively coupled plasma optical emission spectrometry. One mol of albumin bound up to 7, 8.5 and 1.5 mol of compound 1 ([Ru(Cl-tpy)(en)Cl][Cl]), 2 ([Ru(Cl-tpy)(dach)Cl][Cl] and 3 ([Ru(Cl-tpy) (bpy)Cl][Cl]), respectively. One mol of transferrin bound up to 3, 3.5 and 0.4 mol of 1, 2 and 3, respectively. The affinity of albumin and transferrin for the three ruthenium compounds was evaluated using fluorescence quenching. The binding constants for 1 and 2 lay within the range 104–105 M−1, suggesting moderate-to-strong attachment to albumin. Both compounds showed much lower affinity for transferrin (102–103 M−1). Compound 3 bound weakly to each studied protein. High resolution ESI qTOF mass spectra of albumin before and after binding of 1 revealed the high stoichiometry of binding. Although the binding of the compounds 1–3 to albumin and transferrin did not affect proteins’ secondary structure much, their tertiary structures underwent some alterations, as deduced from the circular dichroism study. Changes in the stability of albumin, after binding to compounds 1–3 were examined by differential scanning calorimetry

Supplementary data for article: Dimkic, I.; Stankovic, S.; Nišavic, M.; Petkovic, M.; Ristivojevic, P.; Fira, D.; Beric, T. The Profile and Antimicrobial Activity of Bacillus Lipopeptide Extracts of Five Potential Biocontrol Strains. Frontiers in Microbiology 2017, 8 (MAY). https://doi.org/10.3389/fmicb.2017.00925

Supplementary material for: [https://doi.org/10.3389/fmicb.2017.00925]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2463

Geopolymer/CeO2 as Solid Electrolyte for IT-SOFC

As a material for application in the life sciences, a new composite material, geopolymer/CeO2 (GP_CeO2), was synthesized as a potential low-cost solid electrolyte for application in solid oxide fuel cells operating in intermediate temperature (IT-SOFC). The new materials were obtained from alkali-activated metakaolin (calcined clay) in the presence of CeO2 powders (x = 10%). Besides the commercial CeO2 powder, as a source of ceria, two differently synthesized CeO2 powders also were used: CeO2 synthesized by modified glycine nitrate procedure (MGNP) and self-propagating reaction at room temperature (SPRT). The structural, morphological, and electrical properties of pure and GP_CeO2-type samples were investigated by X-ray powder diffraction (XRPD), Fourier transform infrared (FTIR), BET, differential thermal and thermogravimetric analysis (DTA/TGA), scanning electron microscopy (FE-SEM), energy dispersive spectrometer (EDS), and method complex impedance (EIS). XRPD and matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) analysis confirmed the formation of solid phase CeO2. The BET, DTA/TGA, FE-SEM, and EDS results indicated that particles of CeO2 were stabile interconnected and form a continuous conductive path, which was confirmed by the EIS method. The highest conductivity of 1.86 × 10−2 Ω−1 cm−1 was obtained for the sample GP_CeO2_MGNP at 700 °C. The corresponding value of activation energy for conductivity was 0.26 eV in the temperature range 500–700 °C

The Evaluation of γ-Zein Reduction Using Mass Spectrometry—The Influence of Proteolysis Type in Relation to Starch Degradability in Silages

The starch availability and nutritional value of corn (Zea mays L.) are affected by zein proteins. The aim of the study was to see whether the proposed reduction of γ-zeins during the fermentation of silages is a result of either the enzymatic proteolytic activity or of the acidic environment, and how this reduction affects starch availability and degradability in high-moisture corn. A mass spectrometry (MS) technique was used to quantify the 16- and 27-kDa γ-zeins. Briefly, two-dimensional gel electrophoresis (2-DE) was used for γ-zein separation, followed by densitometry for protein quantification and matrix-assisted laser desorption ionization time-of-flight MS (MALDI-TOF/TOF) for protein identification. The results show that the reduction in γ-zeins induced by the ensiling led to a more pronounced starch availability and in vitro degradation, and this reduction was dependent on the type of proteolysis. More specifically, the results indicate that the reduction of γ-zeins in the ensiled corn was primarily driven by the enzymatic proteolysis. Furthermore, we demonstrated that 2-DE followed by densitometric quantification and the mass spectrometry analysis for protein identification can be used as a state-of-the-art method for γ-zein evaluation both in fresh and fermented/ensiled corn samples

Antimicrobial susceptibility testing of streptococcus suis isolates to common antibiotics used in pig farms

The goal of this study was to determine antimicrobial susceptibility of 34 Streptococcus suis strains isolated from healthy and diseased pigs from two pig farms. Disk diffusion was the method used to asses antibacterial susceptibility of S. suis according to CLSI (Clinical and Laboratory Standards Institute) and EUCAST standard protocols. Overnight cultures of S. suis grown on Colombia 5% blood agar (HIMEDIA, India) were suspended in Todd Hewitt broth (Oxoid Limited, England) and suspension was adjusted to 0,5 McFarland standard. Using sterile swabs suspension was spreaded to Mueller Hinton agar supplemented with 5% defibrinated sheep blood, after which standadized discs containing antimicrobial substances were placed on the agar surface. Plates were incubated at 37 °C in aerobic conditions usually for 18 hours, but no more than 24 hours after which diameter of S. suis inhibition zones were measured. Among 34 isolated S. suis strains all were resistant to tetracycline (TET), lincomycin (L) and clindamycin (CC). Susceptibility was very low to sulfamethoxazole-trimethoprim (SXT) combination (94,1% resistance), 94,1% of strains were sensitive to penicillin G (P), amoxicillin (AMX), erythromycin (E), enrofloxacin (ENR) and azithromycin (AZM) while sensitivity to cephalosporins of the first (cephalexin- CN), third (cefotaxime – CTX, ceftriaxone - CRO) and fourth ( cefepime-FEP) generation, as well as the sensitivity to florfenicol (FFC) and vancomycin (VAN) was absolute (100%). Therefore we can conclude that cephalosporins are very reasonable choice in treatment of human cases of S. suis meningitis but also as a treatment of choice for the S .suis pig septicemia

Supplementary material for the article: Nišavić, M.; Janjić, G. V.; Hozić, A.; Petković, M.; Milčić, M. K.; Vujčić, Z.; Cindrić, M. Positive and Negative Nano-Electrospray Mass Spectrometry of Ruthenated Serum Albumin Supported by Docking Studies: An Integrated Approach towards Defining Metallodrug Binding Sites on Proteins. Metallomics 2018, 10 (4), 587–594. https://doi.org/10.1039/c7mt00330g

Supplementary material for: [https://doi.org/10.1039/c7mt00330g]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2134]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3243