Aleksandar KneževićUniversity of Belgrade · Faculty of Biology
Aleksandar Knežević
PhD
About
48
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638
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Citations since 2017
Publications
Publications (48)
The principal aim of this study was to determine bacterial diversity within the Cave Church of Sts. Peter and Paul, via culturable and non-culturable approaches, and elucidate the antifungal potential of autochthonous antagonistic bacterial isolates against biodeteriogenic fungi. Furthermore, whole-genome sequencing of selected bacterial antagonist...
The fungal community of biodeteriorated 17th century mural paintings within
the nave and altar portion of the old Church of the Holy Ascension (Veliki
Krčimir, Nišava District, Serbia) has been studied via an array of
microscopic analyses in order to detect actively growing fungi and assess
their potential damage to the painted layer and mortar. In...
The mycobiome of the cave Church of Sts. Peter and Paul, housing the peculiar fresco painting of “The Bald-headed Jesus”, was analyzed via culture-dependent and -independent methods. Salt efflorescence, colored patinas, and biofilm, as well as biopitting, discolorations, and fruiting bodies of wood-decay fungi were observed on surfaces within the c...
Eleven 31-methylenlanostane triterpenoids, i.e. seven 21- and four 26-oic acids, as well as a lupane triterpenoid betulin, isolated from the fruiting bodies of the mushroom Fomitopsis betulina were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay....
Significant percent of world cultural heritage artifacts is threatened by fungal infestation. Fungi can deteriorate different substrates via various physical and chemical mechanisms. Hyphal growth and penetration into the substrate can cause symptoms like discoloration, biopitting, cracking, exfoliation and patina formation. On the other hand, chem...
This paper presents new records and noteworthy data on the following taxa in
SE Europe and adjacent regions: parasitic fungus Antherospora hortensis, saprotrophic fungi Loweomyces fractipes and Pholiota henningsii, stonewort Chara canescens, mosses Grimmia caespiticia and Rhodobryum ontariense, fern Woodsia
alpina, monocots Aegilops triuncialis, Ep...
The aim of the study was comparative analysis of degradation of wheat straw lignin by white-rot fungi and its implications on the efficiency of enzymatic hydrolysis of holocellulose. Cyclocybe cylindracea , Ganoderma resinaceum , Irpex lacteus , Pleurotus ostreatus and Trametes versicolor were the species studied. Peroxidases were predominantly res...
Members of the millipede order Julida rely on dominantly quinonic defensive secretions with several minor, non-quinonic components. The free radical-scavenging activities of ethanol, methanol, hexane, and dichloromethane extracts of defensive secretions emitted by Pachyiulus hungaricus (Karsch, 1881) and Megaphyllum unilineatum (C. L. Koch, 1838) w...
Millipedes (Diplopoda) of the order Julida are known to produce mixtures of quinones
(usually as dominant compounds), phenolics, alcohols, esters, aldehydes, ketones, and
anthranilate derivatives as agents of antipredator defense. Apart from the mentioned role,
data on other biological activities of these secretions are scarce. Being soil organisms...
In a last few decades mushrooms are increasingly attracting attention as functional food and sources of biologically active compounds. Several Trametes species have been used for centuries in traditional medicine of East Asia cultures, but only T. versicolor was studied sufficiently while there are less substantial data about medicinal properties o...
This study was aimed to analyze the chemical composition and biological activities of extracts of Salvia fruticosa and S. lanigera originated from Libya. Dichloromethane, ethyl acetate, methanol, ethanol and water extracts obtained from wild growing plants were analyzed for the composition using HPLC-DAD, which revealed presence of phenolic acids a...
This study was aimed to examine chemical composition and biological activities of water, ethanol, methanol, ethyl acetate and dichloromethane extracts of Salvia amplexicaulis Lam. (Lamiaceae). The high performance liquid chromatography (HPLC) analysis showed that the largest amounts of polyphenols were present in methanol extract, followed by ethan...
The aim of this study was to optimize cultivation conditions for Mn-oxidizing peroxidases and laccase production and selective degradation of beech wood and wheat straw lignin by Trametes gibbosa. To promote lignin degradation, the effect of different carbon and nitrogen sources, type of cultivation, enzyme dynamics and inducers were studied. Solid...
Wheat straw is the major crop residue in Europe which makes it the most promising material for bioconversion. However, only 3% of annual production is used directly while the rest is considered as waste. A key step in processing of lignocellulosics is delignification by fungi and the presence of calcium can be of a great importance as it can modula...
This study aimed to evaluate the antifungal, antioxidative, and genoprotective potentials of various extracts of Daedaleopsis confragosa fruiting bodies and mycelia. The extracts exhibited weak fungistatic and an absence of any fungicidal activities against 7 important animal and human pathogens. Although mycelial extracts, especially the hot water...
Considering that mushrooms synthesize different kinds of compounds with
antioxidative activity and that search for natural antioxidants is a topical
study area, testing of unstudied species is fully justified. The aim of the
study was to evaluate antioxidative capacity of Lenzites warnieri
basidiocarps using different solvents. Antioxidative potent...
Plant raw materials could be potential sources for fibre production and this biomass could be also transformed in valued food, feed, energy sources (biofuels), and paper pulp in the processes where fungi take the major role. Effectiveness of these processes depends on capacity of the fungal species but also on the presence of trace elements which c...
Intensive agricultural and industrial production followed by increased production of lignocellulosic wastes, disruption of environment, and depletion of natural resources are features of the modern society. However, these wastes present sustainable resources of fibers and energy and can be useful raw materials for many industries. Therefore, develo...
This is the first report on the phenolic composition and biological activities of endemic species Salvia jurisicii Košanin (Lamiaceae) originating from Macedonia. Aerial parts of S. jurisicii were extracted with dichloromethane, ethyl acetate, methanol, ethanol and water. All extracts were tested spectrophotometrically for total phenolic and flavon...
Wheat straw is the major crop residue in European countries which makes it the most promising material for bioconversion into biofuels. However, cellulose and hemicellulose are protected with lignin, so delignification is an inevitable phase in lignocellulose processing. The organisms predominantly responsible for its degradation are white-rot fung...
At locations in the outdoor area and in the greenhouse of the Botanical Garden “Jevremovac”, a
total of 124 macromycetes species were noted, among which 22 species were recorded for the first
time in Serbia. Most of the species belong to the phylum Basidiomycota (113) and only 11 to the
phylum Ascomycota. Saprobes are dominant with 81.5%, 45.2% bei...
The aim of the study was an assessment of the antioxidant, antifungal and cytotoxic potentials of L. betulinus and T. hirsuta mycelia extracts and the effect of selenium on these activities. Extracts of L. betulinus were twice as efficient in DPPH• scavenging as those of T. hirsuta. The phenol content in Se-enriched L. betulinus extracts was higher...
Trametes species have been used for thousands of years in traditional and conventional medicine for the treatment of various types of diseases. The goal was to evaluate possible antigenotoxic effects of mycelium and basidiocarp extracts of selected Trametes species and to assess dependence on their antioxidant potential. Trametes versicolor, T. hir...
The aim of the study was an assessment of the antioxidant, antifungal and cytotoxic potentials of L. betulinus and T. hirsuta mycelia extracts and the effect of selenium on these activities. Extracts of L. betulinus were twice as efficient in DPPH• scavenging as those of T. hirsuta. The phenol content in Se-enriched L. betulinus extracts was higher...
This study aimed to research the antifungal, antioxidant, and cytotoxic potential of Ganoderma applanatum and Ganoderma lucidum mycelial extracts as well as the possible effect of Se enrichment on these activities. Both Se-enriched and nonenriched extracts of G. applanatum and G. lucidum showed fungi static activity, while a fungicidal effect was n...
The goals of the study were evaluation of antioxidant, antifungal and anticancer potential of Flammulina velutipes mycelium ethanol extract and examination of Se effect on those activities. Both Se-amended and non-amended mycelium extracts exhibited significant antioxidant and antifungal potential. Se-enriched extract was more effective against Can...
The aim of the study was comparative analysis of ligninolytic enzyme productions of Trametes gibbosa and its ability to degrade wheat straw, as well as effect of trace elements on those processes. Mn-oxidizing peroxidases were the main enzymes and the tested trace elements affected their activities mainly inhibitory. Stimulatory effect on Mn-indepe...
The aim of this study was to evaluate the effect of high selenium (Se) concentrations on morphophysiological and ultrastructural properties of Pleurotus ostreatus. Mycelium growth was good in media enriched with 5.0, 10.0, and 20.0 mg L(-1) of Se, concentration of 500.0 mg L(-1) strongly inhibited growth, and 1000.0 mg L(-1) was the minimum inhibit...
The goal of this study was the evaluation of antifungal, antioxidant and anticancer potentials of Pleurotus eryngii, P. ostreatus and P. pulmonarius mycelial extracts, and the influence of mycelium enrichment with selenium on these activities. Both Se-amended and non-amended extracts showed the same or similar minimal inhibitory concentration for 1...
The purpose of this study was to resolve the question of whether various selenium concentrations affect the ability of eight species, members of five genera, to produce mycelium biomass and absorb this trace element during submerged cultivation in Na2SeO3-enriched medium. The obtained results demonstrated the ability of mycelia of all of the tested...
Well developed ligninolytic enzyme system in white-rot mushrooms is responsible for degradation of low degradable and lignin rich unused plant debris, which represents serious environmental ballast. The biological degradation is environmentally friendly and economically justified process. Therefore, assessment of the potential of Trametes pubescens...
Global industrialization and agricultural development are related to the release of various pollutants into the environment including huge amounts of free radicals, which are associated with the occurrence of various destructive diseases and disorders. Due to different rates of metabolic activity and oxygen consumption, organisms, organs and tissue...
Trace elements, at tolerable concentrations, are either part of the active site or act as an activity modulator of ligninolytic enzymes of white-rot mushrooms. They are usually in plant raw materials in a non-toxic amount or non-available and extractable forms. This study evaluated the effects of Fe, Zn, and Se on the activity of laccase and Mn-oxi...
Species of the genus Trametes represent one of the most efficient lignin-degraders which can be attributed to a well developed ligninolytic enzyme system. Current trends are screening of ability of new species to produce these enzymes, as well as the optimization of conditions for their overproduction. Therefore, the aim of the study was to evaluat...
Trametes hirsuta is an efficient lignin-degrading species due to its ability to produce laccase and Mn-dependent peroxidase. Agricultural residues represent prospective substrates for the bioconversion into fungal biomass and lignocellulolytic enzymes, but also they could be potential environmental pollutants. Evaluation of the potential of T. hirs...
To get a better insight into the ligninolytic system of Lenzites betulinus, the effect of wheat straw and oak sawdust, as carbon sources, on production of Mn-oxidizing peroxidases and laccase, under solid-state and submerged fermentation, was studied. Obtained results revealed considerable differences related to the both factors affecting enzyme ac...
Trametes gibbosa is an efficient lignin-degrading species due to its ability to produce laccase and Mn-dependent peroxidase that enable degradation of lignin and of a wide range of structurally similar compounds. Wheat straw is a very common worldwide agricultural residue that contains a certain amount of soluble carbohydrates and inducers of ligno...
Biologically active substances, especially polysaccharides, isolated from fruiting bodies of Trametes species have immunomodulating and antitumor activities. Selenium is a trace element which at nutritional levels has antioxidant and numerous anticarcinogenic or preventive effects, while at higher levels it could be toxic. The purpose of this study...
Projects
Projects (4)
Popularization of the importance of fungal diversity in the protected area "Fungi of Ada Ciganlija", Belgrade, Serbia. Affirmation of the conservation of rare and endangered fungal species through educational activities and habitat protection.
Financial support: Ministry of Environmental Protection, Republic of Serbia, 2019, (Grant No. 401-00-760/2019-05).
The principal aim of the project PROTECTA is to study the causes of the decay of several selected cultural heritage objects in Serbia, and development of novel non-invasive, eco-friendly and safe natural biocontrol method to combat deteriogenic microorganisms responsible for the observed damages, all in order to achieve a sustainable restoration and conservation of deteriorated artwork in Serbia. This will be achieved in cooperation with a team of experts from various cultural institutions via implementation of traditional (sterile swabs, adhesive tape method, etc.) and contemporary (in situ microscopy, ATP bioluminescence method, etc.) methods to study biodeterioration phenomena on investigated works of art, and through screening for novel antimicrobial agents of plant and bacterial origin in vitro, their chemical and molecular characterization, isolation of target compounds of interest and testing potential in situ applicability of new biocide formulations on artificially prepared “mock models” that emulate “real life scenarios”. Additional aim of the project will be the development and implementation of new study protocol to be used in conservation practices and its dissemination to relevant cultural institutions, scientific community involved in “biodeterioration science” and conservation science, as well as general public, with aim of improvement of cultural heritage safeguard and increasing awareness of this still neglected aspect of the “trade”. As such, project PROTECTA fits perfectly with the Program for Excellent Projects of Young Researchers since it promotes science that is neglected in Serbia but very trendy worldwide, which will result in a formation of new research groups, involvement of numerous young researchers into multidisciplinary teams trained in collaboration with the experts in the field, and their preparation to apply for and lead big European projects. For a country rich in cultural heritage, such as Serbia, this is of utmost importance.
