Application of microbial levan as a new component for production of graft copolymer with polystyrene

Polysaccharides based on fructose, also called fructans, are synthetized from sucrose by some plant species and many bacteria, fungi and Archaea. Levan is an exopolysaccharide composed of fructose units and has numerous applications in personal care and cosmetics, medicine and food industry. Polystyrene is the most widespread polymer for plastic production due to its low costing and easy production. Degradation of polystyrene is longterm process, therefore incorporating natural polymers is the desirable approach. In the present study, levan-polystyrene graft copolymer (L-g-PS) was synthetized, characterized and influence of reaction time on grafting reaction at two temperatures was investigated. Levan was isolated after cultivation Bacillus licheniformis NS032. Syntheses of L-g-PS were performed by the free radical reaction using K2S2O8 as initiator. Grafting reactions proceeded in nitrogen atmosphere, at 55ºC and 70ºC and reaction time ranged between 15 and 210 min. FTIR spectra and XRD patterns were recorded using a Thermo Nicolet 6700 Spectrophotometer and Philips PW-1710 automated diffractometer, respectively. The formation of L-d-g-PS was confirmed by FTIR spectra which displayed the presence of all characteristic peaks for both component and X-ray diffractograms which showed amorphous nature of copolymer. Compared to other reaction parameters, the temperature of 70ºC and time of 45 min was more optimal showing higher percentage of grafting

Niskomolekulski inhibitori proteaza mikrobnog porekla

We have witnessed an explosion of informations about properties, also mode of action and regulation of proteases from the metalloproteases at the cell surface to the AIDS protease. Protease inhibitors have a great importance in mechanism of proteolysis. One of the latest strategies to combat diseases like AIDS and cancer is to use proteinase inhibitors as drugs. Especially good source of protease inhibitors are microorganisms. A few low-molecular-weight proetease inhibitors of microbial origin, as a potential drugs, was described.Budući da je upotreba inhibitora aminopetidaza u lečenju SIDE, takođe i kancera različitih vrsta, tzv. nova strategija u lečenju ovih bolesti [18] to je u toku traženje novih inhibitora AP a posebno LAP kao proizvoda metabolizma mikroorganizama, ali i stereoselektivna sinteza jedinjenja koja su im slična [19]. Može se pretpostaviti da će sledećih godina napredak u biohemiji patoloških procesa biti pod velikim uticajem napretka u istraživanju niskomolekulskih inhibitora koje produkuju mikroorganizmi ali i napretka u sintezi analoga ovih jedinjenja

Niskomolekulski inhibitori proteaza mikrobnog porekla

We have witnessed an explosion of informations about properties, also mode of action and regulation of proteases from the metalloproteases at the cell surface to the AIDS protease. Protease inhibitors have a great importance in mechanism of proteolysis. One of the latest strategies to combat diseases like AIDS and cancer is to use proteinase inhibitors as drugs. Especially good source of protease inhibitors are microorganisms. A few low-molecular-weight proetease inhibitors of microbial origin, as a potential drugs, was described.Budući da je upotreba inhibitora aminopetidaza u lečenju SIDE, takođe i kancera različitih vrsta, tzv. nova strategija u lečenju ovih bolesti [18] to je u toku traženje novih inhibitora AP a posebno LAP kao proizvoda metabolizma mikroorganizama, ali i stereoselektivna sinteza jedinjenja koja su im slična [19]. Može se pretpostaviti da će sledećih godina napredak u biohemiji patoloških procesa biti pod velikim uticajem napretka u istraživanju niskomolekulskih inhibitora koje produkuju mikroorganizmi ali i napretka u sintezi analoga ovih jedinjenja

A study of novel cobalt(II) octaazamacrocyclic complexes with aminocarboxylates or their derivativ

Four new air-stable mixed-ligand Co(II) complexes having the general formula [Co2(Y)tpmc]Z3×q(H2O/CH3CN) (HY = N-methylglycine/N,N-dimethylglycine, Z = BF4-, qH2O = 4 or 3; HY = S-norvaline/S-valine Z = ClO4- , qCH3CN = 0.5; qH2O = 0.5; tpmc = N,N’,N’’,N’’’-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) were prepared. The composition, some physical and chemical properties and their tentative geometries were evaluated based on elemental analysis (C, H, N), conductometric and magnetic measurements, spectroscopic data (UV/Vis, IR) and cyclic voltammetry. The data were compared with earlier described analogous complexes containing the macrocyclic ligand and aliphatic aminocarboxylates. It is assumed that all complexes are binuclear with an exo coordination mode of the octaazamacrocyclic pendant ligand in the boat conformation. In addition, two –N–(CH2)2–N– portions of the cyclam ring within the tpmc ligand and Co(II) ions in the high-spin state are most probably bridged via oxygen atoms from the anion of the amino-carboxylate/derivatives, whereas nitrogen atoms rest uncoordinated. In all cases, a combined chelate-bridged coordination is proposed as the most probable. The complexes were electrochemically stable in the potential range –1.0 to 1.0 V. They were also preliminary assayed toward some microorganisms together with the ligands, starting simple salts and solvents as test substances. In some cases, certain antimicrobial activity of the complexes was detected

Izolovanje i delimično karakterisanje proteaze iz Pseudomonas aeruginosa ATCC 27853

Enzymatic characteristics of a protease from a medically important, referent strain of Pseudomonas aeruginosa ATCC 27853 were determined. According to sodium dodecyl sulfate polyacrylamide gel electrophoresis, SDS-PAGE, and gel filtration, it was estimated that the molecular mass of the purified enzyme was about 15 kDa. Other enzymatic properties were found to be: pH optimum 7.1, pH stability between 6.5 and 10; temperature optimum around 60 °C while the enzyme was stable at 60°C for 30 min. Inhibition of the enzyme was observed with metal chelators, such as EDTA and 1,10-phenanthroline, suggesting that the protease is a metalloenzyme. Furthermore, the enzyme contains one mole of zinc ion per mole of enzyme. The protease was stable in the presence of different organic solvents, which enables its potential use for the synthesis of peptides.U ovom radu je okarakterisana ekstracelularna proteaza medicinski značajnog, referentnog soja Pseudomonas aeruginosa ATCC 27853. Molekulska masa prečišćenog enzima određena SDS PAGE i gel filtracijom iznosi oko 15 kDa. Određeni su sledeći enzimski parametri: pH optimum 7,1; pH stabilnost u opsegu 6,5-10; temperaturni optimum 60°C, a enzim je stabilan na 60°C 30 min. Na osnovu inhibicije enzima pomoću EDTA i 1,10-fenantrolina, utvrđeno je da proteaza predstavlja metaloenzim. Pokazano da proteaza sadrži 1 mol jona cinka po molu enzima. Proteaza je stabilna u prisustvu različitih organskih rastvarača, što omogućava upotrebu za sintezu peptida

Gas Chromatography in Environmental Sciences and Evaluation of Bioremediation

Crude oil and its derivatives, as the key energy-generating substances and raw materials used for production, are very widely used in all domains of work and everyday life. With the advent of oil as a fuel, there was the most intense economic growth and it can be said that the entire modern civilization is based on the utilization of oil. However, rapid growth and development of civilization in the past two centuries with the mass use of fossil fuels has led to imbalances and distortions of natural processes. In spite of improvements in technology and equipment used for oil drilling, transport and processing by the petroleum industry, oil and oil derivatives represent a significant source of environmental contamination

Sensitivity to heavy metals and growth on aromatic compounds of bacterial strains isolated from soil contaminated with petroleum products

Aromatični ugljovodonici dospevaju u životnu sredinu na različite načine, kao što su izlivanje nafte, sagorevanje fosilnih goriva, upotreba pesticida, curenje benzina. Pošto su toksični i potencijalno karcinogeni, razvijaju se različite tehnologije za njihovo uklanjanje, a jedna od najvažnijih je bioremedijacija. Brojna istraživanja pokazala su da teški metali utiču na mikrobne zajednice i njihovu aktivnost, jer izmenjuju esencijalne jone metala, ili modifikuju konformaciju proteina. Dejstvo metala zavisi od njegove koncentracije i dostupnosti u medijumu i vrste mikroorganizma. Teški metali su često prisutni u zemljištu kontaminiranom naftnim derivatima. Osetljivost na teške metale smanjuje biodegradacioni potencijal bakterija koje se koriste u procesu bioremedijacije

Termalna stabilnost konjugata polienskog antibiotika sa polisaharidom

Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5057

Dejstvo rifamicina i hloramfenikola na produkciju antibiotika i proteaza soja Streptomyces hygroscopicus CH-7

Streptomycetes are common soil bacteria that grow in a filamentous form and produced spores. Secondary metabolites, particularly antibiotics, as well as extracellular enzymes produced by them have very significant role in the process of differentiation. The Slreptomyces hygroscopicus CH-7 strain produces polyketide antibiotics and an extracellular proteolytic complex. The aim of this work was to establish the influence of transcription and translation inhibitors on biosynthesis of polyene antibiotic and proteolytic enzymes. The inhibitors were added at inoculation and at specific time intervals of fermentation. The production of hexaene H-85 is susceptible to rifamycin (transcription inhibitor) and chloramphenicol (translation inhibitor). Rifamycin reduces the production and trypsin like protease (TLP) and aminopeptidase (AP). while chloramphenicol acts only on TLP. Simultaneously these inhibitors almost have no effect on strain growth.Streptomicete su gram pozitivne bakterije čije je najvažnije stanište zemlja. Pri rastu na čvrstim podlogama i u submerznim uslovima grade supstratni i vazdušni micelijum. Morfološka diferencijacija je praćena produkcijom sekundarnih metabolita kao što su antibiotici, a i različitih hidrolitičkih enzima. Za mikroorganizme koji ih proizvode antibiotici predstavljaju kompetitivno oružje, agense za transport metala kao i efektore diferencijacije. Proteolitički enzimi, takođe, imaju određenu ulogu u razvojnom ciklusu aktinomiceta. Na primer, uključeni su u procese građenja vazdušnog micelija i sporulaciju. Soj Streptomyces hygroscopicus CH-7 pri fermentaciji proizvodi antibiotike poliketidne strukture i smesu ekstracelularnih proteolitičkih enzima. U ovom radu je ispitivan uticaj antibiotika rifamicina i hloramfenikola, inhibitora transkripcije i translacije, na produkciju polienskog antibiotika heksaena H-85 i proteolitičkih enzima. Inhibited su dodavani pri inokulaciji (O h) i u različitim vremenskim intervalima fermentacije (12-48 h). Dejstvom antibiotika inhibitora transkripcije i translacije utvrdjeno je da se enzim polien sintetaza transkribuje do 12. časa, a translacija teče do 48. časa fermentacije. Dodatak rifamicina pri zasejavanju drastično snižava proteolitičku aktivnost, a u kasnijim fazama izaziva smanjenje (36-80%). Hloramfenikol smanjuje produkciju tripsinu slične proteaze. ali nema dejstvo na aminopeptidaznu aktivnost. Rifamicin i hloramfenikol ne pokazuju značajno inhibitorno dejstvo na rast soja

Termalna stabilnost konjugata polienskog antibiotika sa polisaharidom

Poster presented at XLIX Savetovanja Srpskog hemijskog društva, (13-14. maj 2011., Kragujevac)Abstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5056