The Study Of Fungal Diversity In Different Brick-tomb Mural's Diseases And Aerobiology

Widely distributed all over the world with historic sites and cultural relics are the precious wealth of mankind,but the presence of microorganisms pose a threat tohistoricpreservation.Xijin tomb and Han tomb are located at Dunhuang Gobi desert,Jiayuguan NO.5 tomb is located at Gansu Museum,and these tombs are all in semi-underground with delicate brick paintings.These paintings are vivid and including abundant materials,they have important values to explore the ancient civilization.At present,the three rooms under the condition of lack of system protection for a long time,the appearance of similar diseases such as black colonisations and salt efflorescence,what's more these diseases may lead the large area to fall off,that will be irreversible regret for the archaeological research and historical culture.Nowadays there are less research about the three tombs in biodeterioration.This experiment aimed at exploring if the similarity of look disease of the tombs which from different sites(Dunhuang Jin tomb Dunhunag Han tomb and Jiayuguan No.5 tomb)and different period are leaded by microbe,and if the aerobiology could lead to the mural's disease.Combining composition analysis of samples with fungi strain to explore the sample's halophilic,organic acid production and the relationship between fungal growth and environmental factors.Final Destination is in order to give some advices to the national relic protection.This experiment used Buck Bio-Culture? Sampler to collect air samples,cottonswab to collect surface layer samples and sterile scalpel to collect basic layer samples.Using scanning electron microscopy analysis of characteristics of microstructure of mural disease place,and we choose four mediums which are suitable for the fungi to cultivating fungi.By the genomic DNA,the following steps should be the amplification of fungal ITS region,sequencing,and phylogenetic analysis,thereafter the fungal community composition and structure characteristics were clarified.The experiment about the samples' mainly composition main elements analysis we choose spectrometer(EDS),with scanning electron microscope(SEM),then combine with X-ray diffraction(XRD)analysis the crystal composition of the samples.With the method of medium simulation experiment to explore the halophilic of the culturable fungi in the samples and using gas chromatography-mass spectrometry(GC/MS)to explore characteristics of the strains producing organic acid.The results indicate that,in 3 tombs,the highest amount are Pencillium and Aspergillus,and the others included Fusarium,Chaetomium,Cladosporium,ect.On the one hand,we could find the same fungi in the similar disease,so we guess the black colonisations might cause by Penicillium aurantiogriseum,Fusarium chlamydosporum,Penicillium olsonii,and the salt efflorescence might cause by Aspergillus versicolor,Penicillium aurantiogriseum,Aspergillus fumigatus.On the other hand,in the three tombs the diversity of aerobiology is related to the surface layer's,it proved the aerobiology has liquidity and the mural's disease might due to the aerobiology flowing.Comprehensive three tombs environment,we also found the warm moist environment with more people will lead the concentration and the microbial diversity change.Now we know most fuguses which were culturable in the samples have halophilic,all have good growth characteristics in the concentration of 15% salt environment,especially the high abundance Penicillium and Aspergillus,they can grow under even the concentration of 25% to 30%;Penicillium,Cladosporium and Actinomucor have the strong ability to producing acid,organic acid species include succinic acid,citric acid,stearic acid,palmitic acid and so on,these strong organic acid can cause corrosion to the mural.The experiment results show that in the process of cultural heritage protection in the future,it is need to take measures to control the environment and human factors such as temperature,humidity,and tourist;and then the need for cultural relics environment air microbial propagation control.In conclusion,the experiment is to explore the different locations of underground tomb murals in biodeterioration problems and can provide feasible suggestions for the protection of cultural relics.