Micromycetes diversity on cultural heritage objects and testing the fungicides applicable in conservation

Cilj istraživanja doktorske disertacije je bio proučavanje biodeterioracije objekata kulturne baštine u Srbiji. Na osnovu predloga stručnih timova u institucijama za zaštitu objekata kulturne baštine izvršen je odabir istraživanih objekata i predmeta. Spomenici kulture obuhvaćeni u istraživanju bili su: crkva Svete Trojice manastira Sopoćani i crkva Svete Bogorodice manastira Gradac kod Novog Pazara, crkva Svetog Nikole u Paležu, Ajfelova prevodnica kod Bečeja, spomenik Neznanom junaku na Avali, Brankov most u Beogradu i srednjovekovni kameni stećci sa lokaliteta Mramorje i Rastište kod Perućca. Opservacijom in situ opisani su simptomi biodeterioracije: pojava biopatine, izmenjena tekstura kamene površine, fenomen „biopitting“ i drugi. Sa mesta sa vidljivim simptomima biopatine izvršeno je uzorkovanje fragmenata biofilma adhezivnom trakom sa kamenog supstrata. Direktnim posmatranjem fototrofne komponente biofilma, svetlosnim mikroskopom, identifikovane su prisutne cijanobakterije i alge, uzročnici različite obojenosti supstrata. Crvena biopatina na fasadi crkve svete Bogorodice je posledica prisusutva kolonija Gloeocapsa sanguinea (C.Agardh) Kützing dok je Trentepohlia aurea (Linnaeus) C.F. P. Martius izazvala pojavu narandžaste biopatine na istom objektu. Crna katranasta biopatina na Ajfelovoj prevodnici je posledica prisusutva kolonija Nostoc sp., dok je Haematococcus pluvialis Flotow uzročnik narandžaste bio patine na spomeniku Neznanom junaku. Cijanobakterija Oscillatoria sp. i zelena alga Cylindrocistis brebissonii (Ralfs) de Bary su uzročnici zelene biopatine na istom objektu...The aim of presented PhD thesis was research of biodeterioration of cultural heritage objects in Serbia. The objects and artefacts for this study were chosen according to the recomendations of the experts in the field of cultural heritage conservation. Cultural heritage monuments chosen for this study were The Church of The Holly Trinity of the Monastery Sopoćani (Novi Pazar), The Holly Virgin Church of the Monastery Gradac (Novi Pazar), Saint Nicholas church (Palež), Eiffel’s Lock (Bečej), Monument of the Unknown Hero (Avala), bridge „Brankov most“ (Belgrade) and medieval tombstones on two localities Mramorje and Rastište (Perućac). During in situ observations of examined stone monuments clear signs of biodeterioration were observed, such as presence of biopatinas, changed texture of stone surface, biopitting and other. Biofilm fragments were sampled using adhesive tape from the stone surfaces with visible biopatinas and examined using light microscopy in order to identify cyanobacteria and algae as phototrophic components of biofilm. It was shown that causative agent of red biopatina on the facade of Holly virgin church was Gloeocapsa sanguinea (C.Agardh) Kützing colonies, while Trentepohlia aurea (Linnaeus) C.F. P. caused the orange biopatina on the same monument. Black gelationous patina on Eifel’s Lock was caused by Nostoc sp. colonies. Haematococcus pluvialis Flotow caused the orange biopatina on the Monument of the Unknown Hero..

Work verification of the energy steam boiler evaporator in the Power plant 'Kostolac B'

U okviru Elektroprivrede Srbije 1991. godine puštena je u rad Termoelektrana 'Kostolac B' snage 2 × 350 MW. Na osnovu dosadašnjih ispitivanja cevnog sistema parnog kotla utvrđeno je da se on nalazi u 'lošem' stanju. Njegovi najugroženiji delovi su isparivačke grejne površine. S obzirom da postoje oblasti u isparivaču koje su se češće oštećivale, zbog čega je parni kotao ispadao iz pogona, neophodno je utvrditi razloge zbog kojih je dolazilo do tih oštećenja. Da bi se locirala ugrožena područja isparivača, sproveden je detaljan hidraulički proračun. Takođe je izvršen termički proračun parnog kotla u celini, s obzirom da se isparivač nalazi i u zoni konvektivnih grejnih površina. Utvrđivanjem najugroženije lokacije isparivača - horizontalni deo nosećih cevi, omogućeno je da se pri kapitalnom remontu izvrše određene rekonstrukcije u smislu promene njihovog ugla nagiba, što bi u krajnjem obezbedilo sigurniji rad, kako isparivača tako i kotla u celini.Within Electric Power Utility of Serbia 1991, a thermal power plant 'Kostolac B', power 2 × 350 MW, started. Based on the examination of steam boiler pipe system, it is confirmed that it is in a 'bad' shape. Its most jeopardized parts are evaporating heating surfaces. Considering that there are areas within the evaporator that suffered more damage, wherefore the steam boiler is out of production, it is necessary to settle the reasons for those damages. In order to locate the jeopardized areas of the evaporator, we carried out a detailed hydraulic calculation. A thermal calculation of steam boiler was also carried out, considering that the evaporator is also located in the convective heating surfaces part. By settling the most jeopardized evaporator locations - a horizontal part of support tubes, it was enabled to make certain reconstructions during the capital repair, in regard of changing their inclination angle, which would provide safer work of the evaporator, and steam boiler as a whole

Hidden dwellers on green frog’s skin (Pelophylax esculenta complex)

Recent research of frog skin microbiota were mainly focused on presence of pathogens, especially Batrachochytrium dendrobatidis, as well as on describing the bacterial communities on their skin. e specialized amphibian lifestyle where frogs’ skin is in intimate contact with the environment is of primary importance in determining frogs’ resilience to external factors. Cutaneous microbiota is thus an indicator of both frog health as well as of environmental factors acting upon frogs. Many of these factors can be detrimental to frog fitness and it is expected that the first changes in frog fitness could be assessed by identifying the changes in diversity patterns of frog’s skin epibiotic communities and/or isolating specific pathogens. Knowledge of these communities and patterns could contribute to more efficient conservation. Epibiotic communities of the green frog complex (Pelophylax esculenta complex), sampled on three localities in South Banat, Serbia (Stevanove Ravnice, Jaruga canal, DanubeTisaDanube Canal) were investigated using culture depended methods and microscopy techniques. Samples were collected using three sampling methods: 1) scraping by toothbrush for algal sample 2) swabbing with sterile cotton swabs for fungal sample and 3) nonaggressive adhesive tape method for both algal and fungal sample. e aim of this research was describing fungal and algal communities present on frogs’ skin. Culture based methods showed high diversity of airand soilborne fungi (members of genera Acremonium, Alternaria, Aspergillus, Bionectria, Bipolaris, Botrytis, Cladosporim, Epicoccum, Fusarium, Penicillium, Trichoderma, Ulocladium, to name a few), which could be considered transients. However, microscopy techniques revealed spore germination, mycelia formation and sporulation directly on frog skin, of some typical soilborne fungi eg. Fonseceae sp., causative agent of amphibian chromomycoses as well as human phaeohyphomycosis. Microscopy analyses of samples taken or scraped from amphibians’ skin showed the presence of morphological structures belonging to aeroaquatic hyphomycetes (eg. Canalisporium sp.) and stramenopiles, as well as high abundance of diatoms. Presence of c. 40 diatom genera was observed with dominance of mostly ubiquitous eurivalent species found in highly eutrophic waters (members of genera Amphora, Craticula, Cymbella, Cymbopleura, Cymatopleura, Diploneis, Encyonema, Epithemia, Fallacia, Gomphonema, Luticola, Navicula, Neidium, Nitzschia, Pinnularia, Planothidium, Rhopalodia, Staurosira and Surirella). Investigation of microbial communities on frog skin is of great importance due to potential detection of novel amphibian pathogens, and also can lead to better understanding of amphibianmicrobial interactions, which in further researches can be used as effective tool in amphibian protection.Explore and protect the natural beauty of Balkans. International Rufford Small Grants Conference. 27th – 28th September, 2018, Silver Lake, Serbia

Biofilm forming cyanobacteria, algae and fungi on two historic monuments in Belgrade, Serbia

Biofilm on the sandstone substrata of the bridge 'Brankov most' and on the granite substrata of the 'Monument of the Unknown Hero' contains a complex consortia of cyanobacteria, algae, and fungi. Coccoid and filamentous cyanobacteria, green algae and diatoms make up the photosynthetic part of the biofilm while hyphal fragments, chlamydospores, fruiting bodies and spores take part as fungal components. These structures make a dense layer by intertwining and overlapping the stone surface. Five cyanobacterial, 11 algal and 23 fungal taxa were found. The interaction of the biofilm's constituents results in the bioweathering of the stone substrata through mechanical penetration, acid corrosion and the production of secondary mycogenic biominerals.

Mold attack on frescoes and stone walls of Gradac monastery

Microfungi can colonize stone surfaces and form sub-aerial biofilms which can lead to biodeterioration of historic monuments. In this investigation samples for mycological analyses were collected from stone material with visible alteration on stone walls of Gradac monastery exterior. The prevailing fungi found on stone walls were dematiaceous hyphomycetes with melanized hyphae and reproductive structures (Alternaria, Aureobasidium, Cladosporium and Epicoccum species). The frescoes inside the monastery building were also analyzed for the presence of mycobiota. The predominant fungi found on frescoes were osmophilic species from genera Aspergillus and Penicillium. The significant result is identification of human pathogen species Aspergillus fumigatus on frescoes

Comparison of calibration factors for field-class dosimeters

This paper presents a comparison performed between two calibration laboratories in several radiation qualities, using dosimeters of varying quality as transfer instruments. The goal of this work was to investigate the viability of using field-class dosimeters for official comparisons and to determine if the calibration factors for field-class dosimeters are comparable between calibration laboratories within the stated measurement uncertainties. The results of the comparison were acceptable for high-quality electronic personal dosimeters in all radiation qualities, and such dosimeters could be used as transfer instruments. On the other hand, comparison results for low-quality dosimeters were often not acceptable, either due to pronounced energy dependence, low stability, or both. Such instruments are unreliable even under well-defined laboratory conditions, and their use in routine measurements may cause doubt in official data or influence public opinion. This problem is often hidden because many dosimeters are calibrated or verified only in 137Cs beams, where the deviations are the smallest. The largest differences are found for low-energy X-ray radiation qualities, where many dosimeters have significant overresponse

Comparison of anti-Aspergillus activity of Origanum vulgare L. essential oil and commercial biocide based on silver ions and hydrogen peroxide

The antifungal activities of Origanum vulgare essential oil (EO) and of a biocide based on silver and hydrogen peroxide (Sanosil S003) against seven Aspergillus species isolated from different substrata (stone, brick, silk and paper) of cultural heritage objects in Serbia were evaluated. Microdilution, agar dilution and microatmosphere methods were used to determine minimal fungistatic and minimal fungicidal concentrations (MIC and MFC), and light microscopy to determine structural abnormalities. MIC and MFC values for O. vulgare EO ranged from 0.2 to 5 mg mL−1 and for Sanosil S003 from 5 to 250 mg mL−1. Aspergillus sp. sect. fumigati was the most susceptible isolate, where MIC and MFC values were achieved at 0.5 mg mL−1 for O. vulgare EO, while MIC and MFC values for Sanosil S003 were achieved at 5 and 10 mg mL−1, respectively. Morpho-physiological changes were documented in all isolates, including lack of sporulation, depigmentation of conidiogenous apparatus and conidia, and presence of aberrant fungal structures. O. vulgare EO exhibited stronger anti-Aspergillus activity than Sanosil S003, as demonstrated by the higher MIC and MFC values and fewer morpho-physiological changes observed in the tested Sanosil S003 concentrations. O. vulgare EO could be an excellent alternative to commercial biocides, with high potential in the field of cultural heritage conservation

Antifungal activity of Nepeta rtanjensis essential oil

The chemical composition and antifungal activity of the essential oil of an endemic Serbian plant Nepeta rtanjensis Diklić & Milojević was studied. The essential oil was isolated from cultivated plants. Inhibition of mycelia growth of five micromycetes, two Alternaria species originally isolated from N. rtanjensis, Cladosporium cladosporoides, Trichoderma viride and Bipolaris spicifera, were tested using the agar dilution method. The essential oil of N. rtanjensis, the main component of which was 4aα,7α,7αβ-nepetalactone, showed strong antifungal activity against all the tested micromycetes. The minimum inhibitory concentration of N. rtanjensis essential oil ranged from 0.6 to 1.4 μg mL-1. The fungi most sensitive to the tested oil were Alternaria species, while Trichoderma viride was the most resistant.U ovom radu prezentovan je hemijski sastav i antifungalna aktivnost etarskog ulja endemične biljke Nepeta rtanjensis Diklić & Milojević. Etarsko ulje je izolovano iz kultivisanih biljaka. Inhibicija micelijalnog rasta pet mikromiceta, dve vrste roda Alternaria, izolovane sa N. rtanjensis, Cladosporium cladosporioides, Trichoderma viride i Bipolaris spicifera, testirana je makrodilucionom metodom. Etarsko ulje N. rtanjensis, čija je glavna komponenta 4aα,7α,7aβ-nepetalakton pokazuje jaku antifungalnu aktivnost u odnosu na sve testirane mikromicete. Minimalna inhibitorna koncentracija (MIC) etaskog ulja bila je u rasponu od 0,6 μg mL-1 do 1,4 μg mL-1. Najveću osetljivost na testirano ulje pokazale su vrste roda Alternaria dok je Trichoderma viride bila najotpornija.Projekat ministarstva br. 143041

Measurement of 60CO gamma radiation induced attenuation in multimode step-index POF at 530 nm

As optical fibres are used ever more extensively in space applications, nuclear industry, medicine and high-energy physics experiments, it has become essential to investigate the influence of ionizing radiation on their characteristics. In this work, the radiation-induced attenuation at 530 nm is investigated experimentally in step-index multimode polymethyl-methacrylate plastic optical fibres exposed to low dose-rate gamma radiation. Cumulative doses ranged from 50 Gy to 500 Gy. The radiation induced attenuation has been empirically found to obey the power law RIA= aDb, where D is the total radiation dose and a and b are the constants determined by fitting

Fungal Deterioration of Cultural Heritage Objects

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, chemical mechanisms include acid secretion, release of extracellular enzymes, pigment production, oxidation/reduction reactions and secondary mycogenic minerals formation. These processes can lead to serious, both esthetic and structural, alterations which may be irreversible and could permanently impair artworks. Proper isolation and identification of autochthonous isolates, as well as employment of different microscopic techniques and in vitro biodegradation tests are pivotal in understanding complex biodeterioration mechanisms caused by microorganisms, including fungal deteriogens. Biodeterioration and biodegradation studies require multidisciplinary approach and close collaboration of microbiologists, chemists, geologists and different personnel responsible for the safeguarding of cultural heritage monuments and artifacts, especially restorers and conservators