Uloga tiolne grupe u modifikaciji proteina sa metilglioksalom

Methylglyoxal is a highly reactive a-oxoaldehyde with elevated production in hyperglycemia. It reacts with nucleophilic Lys and Arg side-chains and N-terminal amino groups causing protein modification. In the present study, the importance of the reaction of the Cys thiol group with methylglyoxal in protein modification, the competitiveness of this reaction with those of amino and guanidine groups, the time course of these reactions and their role and contribution to protein cross-linking were investigated. Human and bovine serum albumins were used as model systems. It was found that despite the very low levels of thiol groups on the surface of the examined protein molecules (approx. 80 times lower than those of amino and guanidino groups), a very high percentage of it reacts (25-85%). The amount of reacted thiol groups and the rate of the reaction, the time for the reaction to reach equilibrium, the formation of a stable product and the contribution of thiol groups to protein cross-linking depend on the methylglyoxal concentration. The product formed in the reaction of thiol and an insufficient quantity of methylglyoxal (compared to the concentrations of the groups accessible for modification) participates to a significant extent (4%) to protein cross-linking. Metformin applied in equimolar concentration with methylglyoxal prevents its reaction with amino and guanidino groups but, however, not with thiol groups.Metilglioksal je veoma reaktivni α-oksoaldehid koji se povećano stvara u hiperglikemiji. Reaguje sa nukleofilnim grupama bočnih ostataka Lys, Arg i N-terminalnom amino-grupom, što dovodi do modifikacije proteina. U ovom radu ispitivani su značaj reakcije SH grupe sa metilglioksalom u modifikaciji proteina, konkurentnost ove reakcije u odnosu na reakcije sa amino- i gvanidino-grupom, tok ovih reakcija i njihova uloga i doprinos u umrežavanju proteina. Kao model-sistemi upotrebljeni su humani i goveđi serum-albumin. Utvrđeno je da i pored veoma male zastupljenosti SH grupe na površini ispitivanih molekula proteina (oko 80 puta manja u odnosu na ukupan broj amino- i gvanidino-grupa), ona reaguje u velikom procentu (od 25-85 %). Količina izreagovanih SH grupa i brzina reakcije, vreme uspostavljanja ravnoteže reakcije, stvaranja stabilnog proizvoda i doprinos SH grupa umrežavanju proteina zavise od koncentracije metilglioksala. Proizvod stvoren u reakciji SH grupa i nedovoljne količine metilglioksala (u odnosu na koncentraciju grupa dostupnih za modifikaciju) učestvuje u umrežavanju proteina sa značajnim udelom (4 %). U ekvimolarnoj koncentraciji sa metilglioksalom metformin sprečava njegovu reakciju sa amino i guanidino grupama albumina, ali ne i sa tiol grupom

Avarol effectively inhibits bacillus cereus growth

This work extends in vitro screening of antibacterial activity of avarol on four selected pathogenic bacteria associated with psoriasis (Bacillus cereus, Clostridium sporogenes, Enterococcus faecalis and Staphylococcus aureus). Avarol exhibited a moderate activity with minimum inhibitory and minimum bactericidal concentrations ranged from 0.78-1.56 and 3.12-18.75 μg/mL, respectively. It proved to be more effective against B. cereus in comparison to the both positive controls applied, gentamycin and ampicillin. According to the experimental data, this marine natural product may inspire development of new antibiotics with an enhanced therapeutic index, at first place those targeting B. cereus

Socijalna distanca većinske populacije prema slepim osobama pre tri decenije i danas

Social distance is operationalized as the willingness of respondents to accept or reject a particular social relationship with members of the target group. Comparison of available empirical findings on the social distance towards the blind at several points of time did not lead to unambiguous conclusions. Therefore, we fully repeated the research from 1983. The aim was to determine the changes in the order of questions in the scale and the differences in social distance toward the blind for the complete scale and each of the items in the studies conducted in 1983 and 2016. In both studies the same modified Bogardus scale was used in a quota sample of adults. The results show that the closest social relationships (marriage and intimate relationships) are still at the top of the scale. Several items in the scale have changed ranking significantly (superiors at work, sharing hotel rooms, killing blind-born children). Values of the Chi-square test showed that there are significant differences in the complete scale and in the following relations: sharing hotel rooms (significantly increased distance), child marriage, child education, help in the street, municipality councilor, superiors at work, living in special institutions (significant reduction in distance). Qualitative analysis showed that the motivational basis for accepting and rejecting relationships with blind persons is less irrational today than three decades ago. Although smaller social distance in the recent study can partly be attributed to a lower degree of aggressiveness of respondents compared to that from the previous study, the fact that the explanations of answers today are far more rational than three decades ago shows that positive changes have actually occurred.Socijalna distanca se operacionalizuje kao spremnost ispitanika da prihvati ili odbaci određene socijalne odnose s pripadnicima ciljne grupe. Poređenje raspoloživih empirijskih nalaza o socijalnoj distanci prema slepim osobama u nekoliko vremenskih trenutaka nije dovelo do jednoznačnih zaključaka. Stoga smo u potpunosti ponovili jedno istraživanje iz 1983. godine. Cilj istraživanja je utvrđivanje promena u stepenu spremnosti većinske populacije da prihvati neke socijalne relacije sa slepim osobama. Realizovan je na osnovu poređenja ranga/redosleda pitanja iz istraživanja sprovedenih 1983. i 2016. godine i razlika u socijalnoj distanci prema slepim osobama za skalu u celini i za svaki od ajtema u ova dva istraživanja. U oba istraživanja primenjena je ista modifikovana Bogardusova skala na kvotnom uzorku odraslih osoba. Rezultati pokazuju da su u vrhu skale i dalje najprisniji socijalni odnosi (brak i intimni odnosi). Nekoliko ajtema je bitno promenilo rang u skali (pretpostavljeni na poslu, deljenje hotelske sobe, ubijanje sleporođene dece). Vrednosti Hi-kvadrat testa podudaranja pokazuju da postoje značajne razlike za skalu u celini i relacije: deljenje hotelske sobe (značajno povećana distanca), brak deteta, obrazovanje i vaspitanje deteta, pomoć na ulici, odbornik u opštini, pretpostavljeni na poslu, život u specijalnim ustanovama (značajno smanjena distanca). Kvalitativna analiza je pokazala da je motivaciona osnova za prihvatanje i odbacivanje socijalnih odnosa sa slepim osobama danas manje iracionalna nego pre tri decenije. Iako se manja socijalna distanca u novijoj studiji delom može pripisati nižem stepenu agresivnosti ispitanika u poređenju sa onima iz prethodne studije, činjenica da su obrazloženja odgovora danas mnogo racionalnija nego pre tri decenije pokazuje da je zaista došlo do pozitivnih promena

Supplementary data for the article: Pejin, B.; Stanimirovic, B.; Vujovic, D.; Popovic Djordjevic, J.; Velickovic, M.; Tesevic, V. The Natural Product Content of the Selected Cabernet Franc Wine Samples Originating from Serbia: A Case Study of Phenolics. Natural Product Research 2016, 30 (15), 1762–1765. https://doi.org/10.1080/14786419.2015.1135148

Supplementary material for: [https://doi.org/10.1080/14786419.2015.1135148]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2301

Supplementary material for the article: Stanimirović, B.; Djordjević, J. P.; Pejin, B.; Maletić, R.; Vujović, D.; Raičević, P.; Tešić, Ž. Impact of Clonal Selection on Cabernet Franc Grape and Wine Elemental Profiles. Scientia Horticulturae 2018, 237, 74–80. https://doi.org/10.1016/j.scienta.2018.03.043

Supplementary material for: [https://doi.org/10.1016/j.scienta.2018.03.043]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2141

Supplementary material for the article: Stanimirović, B.; Djordjević, J. P.; Pejin, B.; Maletić, R.; Vujović, D.; Raičević, P.; Tešić, Ž. Impact of Clonal Selection on Cabernet Franc Grape and Wine Elemental Profiles. Scientia Horticulturae 2018, 237, 74–80. https://doi.org/10.1016/j.scienta.2018.03.043

Supplementary material for: [https://doi.org/10.1016/j.scienta.2018.03.043]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2141

In vitro Radioprotective Activity of the Bryozoan Hyalinella punctata

The objective of the present study was in vitro evaluation of radioprotective activity of the freshwater bryozoan Hyalinella punctata on cultured human peripheral blood lymphocytes after irradiation with 2 gy of Co-60 gamma-rays. Since its water extract at concentration 0.001 mg/mL reduced the incidence of radiation-induced micronuclei for almost 30 %, it could be considered as a promising source of new natural products with the aforementined activity. Both the content of sulphur (1.17%) determined by gravimetric method and infrared absorption frequences (76 % similarity with those of bacitracin) of the investigated extract indicate the presence of organic sulphur compound(s) such as cyclic peptides and polypeptides which might be responsible for the observed radioprotectio

Microbially-induced deterioration of concrete from hydroelectric power plants – an initial study

Microorganisms can grow on the surface of concrete and inside its pores and microcracks, producing different metabolites. Microbial metabolites, particularly acids, degrade concrete components and enhance its deterioration by abiotic factors. Deterioration of concrete is a serious problem worldwide since it affects construction functionality and requires high maintenance costs. This paper presents microbiological and chemical analyses of 12 concrete samples originating from 6 hydroelectric power plants in Serbia, investigated in order to evaluate the key chemical factors affecting microbial growth on concrete. In most of the concrete samples, microorganisms from all examined groups were present in high numbers (bacteria 8.64 × 103–3.4 × 108, fungi 9 × 102–2.08 × 106, sulphur-oxidising bacteria 16.8–2.5×104 CFU/g). The high number and the presence of various physiological groups of microorganisms indicate the high intensity of deterioration caused by biological sources. Values of pH of the concrete samples were in the range 8.46–11.23, Ca content 5.43–19.93%, Fe 151–61100 ppm, sulphate 37.4–623.7 ppm and chloride 96.3–914.1 ppm. Correlation analysis between microbiological and chemical factors indicated a statistically significant strong negative correlation between sulphur-oxidising bacteria and pH (–0.759, p < 0.01)

Microbially-induced deterioration of concrete from hydroelectric power plants – an initial study

Microorganisms can grow on the surface of concrete and inside its pores and microcracks, producing different metabolites. Microbial metabolites, particularly acids, degrade concrete components and enhance its deterioration by abiotic factors. Deterioration of concrete is a serious problem worldwide since it affects construction functionality and requires high maintenance costs.This paper presents microbiological and chemical analyses of 12 concrete samples originating from6 hydroelectric power plants in Serbia, investigated in order to evaluate the key chemical factorsaffecting microbial growth on concrete. In most of the concrete samples, microorganisms from allexamined groups were present in high numbers (bacteria 8.64 × 103–3.4 × 108, fungi 9 × 102–2.08× 106, sulphur-oxidising bacteria 16.8–2.5×104 CFU/g). The high number and the presence of variousphysiological groups of microorganisms indicate the high intensity of deterioration caused bybiological sources. Values of pH of the concrete samples were in the range 8.46–11.23, Ca content5.43–19.93%, Fe 151–61100 ppm, sulphate 37.4–623.7 ppm and chloride 96.3–914.1 ppm. Correlation analysis between microbiological and chemical factors indicated a statistically significant strong negative correlation between sulphur-oxidising bacteria and pH (–0.759, p < 0.01)

Deterioration of concrete in hydroelectric power plants- chemical and microbiological factors

Degradacija betona može da bude posledica različitih fizičkih promena kao što su korozija, pucanje, preopterećenje itd. Osim fizičkih promena, na izdržljivost betona mogu da utiču i mikroorganizmi u procesu biodeterioracije. Iako biodeterioracija retko može biti direktan uzrok degradacije, ona znatno ubrzava druge štetne procese kao što su prodor hlorida i karbonacija koji narušavaju strukturu betona [1]. U procesima biodeterioracije mogu da učestvuju različiti mikroorganizmi kao što su bakterije, gljive, alge, lišajevi [2]. Oni utiču na procese deterioracije betona na tri načina: narušavanjem izgleda, što je posledica formiranja biofilma, mehaničkim pucanjem usled rasta i kretanja mikroorganizama i hemijskim putem usled ekskrecije metabolita [3]. Na početku, pH betonske površine je veoma visoka, pa će, ukoliko je vlažnost i količina hranljivih supstanci dovoljna, doći do kolonizacije alkalifilnim i tionskim bakterijama. Produkcijom oksidovanih sumpornih jedinjenja snižava se pH vrednost što povećava kolonizaciju betonske površine neutrofilnim, a potom i acidofilnim mikroorganizmima. Osim promene pH vrednosti, kiseline koje se proizvode direktno utiču na strukturni integritet betona pošto razgrađuju cementni materijal [2]. Usled deterioracije, troškovi održavanja betonskih konstrukcija je povećavaju, što svake godine prouzrokuje znatnu ekonomsku štetu [1, 2, 3]. U okviru ove studije ispitivan je odnos između mikrobnog rasta i različitih hemijskih svojstava uzoraka poreklom iz tri hidroelektrane u Srbiji (HE Đerdap, HE Potpeć, HE Uvac). Uzorkovanje je radjeno na dva mesta na svakoj lokaciji. Ispitivan je broj ukupnih, gvožđevitih, sulfat-redukujućih i tionskih bakterija, kvasaca i plesni kao i pH vrednost i sadržaj sulfata, nitrata, hlorida, mangana, gvožđa, magnezijuma i kalcijuma. Vrednosti pH su bile u opsegu od 8,39- 9,09, koncentracije gvožđa su bile između 151,0- 61.100,0 mg/L, mangana 7,2- 4.900,0 mg/L, sulfata 37,4- 623,7 mg/L, nitrata 1,0- 11,3 mg/L, hlorida 88,2- 1.104,2 mg/L, kalcijuma 5,48- 19,93% i magnezijuma 0,11- 1,26%. Maksimalan broj ukupnih bakterija je bio 6,24x108 cfu/g, kvasaca i plesni 3,12x105 cfu/g, sulfat redukujućih bakterija 2,20x103 cfu/g , tionskih bakterija 2,50x104 cfu/g, a gvožđevitih bakterija 6.4 x 106 cfu/g. Broj mikroorganizama i njihova aktivnost se uobičajeno povezuje sa osnovnim fizičko-hemijskim i hemijskim karakteristikama ispitivanih uzoraka. Hemijski faktori se u ovim uzorcima znatno razlikuju u zavisnosti od mesta uzorkovanja, zbog čega nije moguće odrediti jedan faktor koji bi bio indikator biodeterioracije. Ipak, uzorci uzeti iz HE Đerdap imaju najveći broj tionskih i sulfat-redukujućih bakterija, kao i najveću koncentraciju hlorida. Jedan od uzoraka uzetih iz HE Potpeć imao je najniži broj svih određivanih mikroorganizama kao i ekstremno visoke koncentracije gvožđa i mangana