Contamination of mural paintings by indoor airborne fungal spores

Summary The processes of biodeterioration on mural paintings have often been discussed, whereas the causes of contamination have seldom been examined.Many microorganisms responsible for the biodeterioration of paintings are of airborne origin. It follows that an investigation on the aerial microbial concentration and air movements in painted indoors is very useful.This paper reviews the literature of mural painting biodeterioration and the aerobiological studies of painted indoors. Hypogean environments, for their particular microclimatic conditions, are not considered.The fungal species most frequently found in the biodeterioration of wall-paintings are reported, as well as comparisons of surface contamination and aerobiological investigation.This review shows the necessity of finding the best sampling methodologies for cultural heritage studies. The control of airborne contamination and proper sampling methods are highly important in determining treatment strategies for the conservation and prevention of microbial attack on painted surfaces.     

Biodeterioration of mural paintings in a rocky habitat: The Crypt of the Original Sin (Matera, Italy)

The biological colonization of mural paintings in rocky habitats is a widely recurring phenomenon and should be considered for restoration activities. In order to plan conservation treatment of the Crypt of the Original Sin (Matera, Italy), biodeterioration problems were analysed taking into account their impact on the substrate and their relationship with environmental factors. The mural paintings showed a phenomenology of alteration varying from brilliant green, dark green, brown, and black duff patinas with powdery aspect, to rosy discoloration. These phenomena were linked to different microbial colonizations by Cyanobacteria (Chlorogloea microcystoides, Chroococcus lithophilus, Gloeocapsa spp., Gloeothece rupestris, Pseudocapsa dubia) and green algae (Apatococcus lobatus, Chlorella vulgaris, Chlorococcum sp., Muriella terrestris). The rosy discoloration was connected to pigment production by Actinobacteria related to Rubrobacter radiotolerans. Grey-green patinas, limited to more ventilated areas, were caused by lichen growth (Dirina massiliensis f. sorediata). Vascular plants (Adiantum capillus-veneris) were also detected in wall areas affected by rising damp. To control the growth of microflora, biocide treatment and intervention to reduce humidity and sunlight exposure of mural paintings were suggested. To choose the correct biocide, different products were tested, evaluating their efficiency on Cyanobacteria and algae as well as possible effects on the calcarenite stone.     

Biodecay of cultural heritage as a space/time-related ecological situation — an evaluation of a series of studies

Mural paintings and stone monuments are exposed to natural and man-made hazards for time spans sometimes longer than 10,000 years without total decay. On the other hand, a high percentage of the mineral physical heritage suffers severe damage and even total loss within a few decades. Several factors influence this general situation. The mural paintings of Lascaux and Altamira had been stabilized in a protective environment for millennia until they were re-exposed to severe environmental risks. Wall paintings and stone sculptures may remain unaltered for many years through: (1) stabilized and protective environments, (2) development of a protective patina (biofilm, minerals, organics) or, (3) more recent additional paint or mortar layers, which themselves are exposed to environmental hazard instead of the fresco underneath. Natural or artificial coverage, however, will invariably hinder evaluation and appreciation of the object of art. Detrimental microorganisms often only sporadically interact with these precious paintings. Many microbes settling on and in mural paintings are of a unusual metabolic type, namely poikilotrophic organisms. These poikilotrophs are capable of forming a biocoenosis on and in mural paintings, which may establish itself within a few months or years and then remains unchanged in a dormant or non-cultivable state for many years, or even centuries. The same holds true for chemical and physical alterations brought about by microorganisms. After a damaging initiation period of growth, the microflora may turn into a biofilm, which continues to live at extremely low levels of metabolic activity. In this way, detrimental chemical, physical and biological activities may be screened or shielded off for a very long period of time. In order to understand these processes, we have studied poikilotroph sub-aerial biofilms of mural paintings and sculptures excavated after long periods of dormancy. Several methods for the characterization of the physical properties of the colonies of fungi involved in colonization and deterioration of mural paintings and stone monuments are described. The fairy-tale of “The Sleeping Beauty” maybe an excellent metaphor for this phenomenon. The main issue, however, is to understand the physical or mechanical impact of the poikilotroph flora on the materials of the physical heritage studied.     

岩画和壁画类文物微生物病害研究进展

古代岩画和壁画是人类文明发展历史进程的重要记录,具有极高的历史价值、艺术价值及科学价值,但他们无时无刻不受到环境因素引起的物理、化学及生物的劣化作用。近年,有关微生物对古代岩/壁画的危害逐渐受到关注。阐述了世界一些著名的岩/壁画文物的微生物的研究进展,如法国拉斯科洞穴岩画(Lascaux Cave)、西班牙阿尔塔米拉洞穴岩画(Altamira Cave)、敦煌石窟壁画、嘉峪关魏晋墓壁画以及我国东北地区公元5世纪的墓葬壁画等。通过对以上所述岩画和壁画微生物群落的分析比较,发现主要的细菌群落是变形菌门和放线菌门,放线菌门以假诺卡氏菌为主。真菌群落主要以虫生真菌为主。进一步分析了岩画和壁画微生物病害的共性和区别,揭示了洞穴、墓室等特殊环境下的微生物群落特点,为防治古代岩/壁画微生物病害提供了以下借鉴。     

Airborne-pollen map for Olea europaea L. in eastern Andalusia (Spain) using GIS: Estimation models

Estimations based upon geostatistics and mapping have enabled the construction of a spatial model to predict the presence of biological particles in a particular region. This methodological proposal has been tested in a case study, at a regional scale, of airborne Olea pollen, using the data acquired from␣various sampling stations that are designed for the aerobiological monitoring of pollen levels. These sampling stations have been set up in cities throughout the region of Andalusia (southern Spain) at sites with very different characteristics in terms of biogeography, bioclimate, topography and vegetation. Pollen counts were made daily at all sites during 2003 using a volumetric spore-trap. Data were comparatively analysed in classical diagrams and by means of spatial-temporal maps. Space-time models were constructed using three coordinates, x, y (the UTM coordinates of each sampling station) and z, (the aerobiological data compiled for a specific period). The aerobiological data were interpolated by applying the traditional geostatistical method of Kriging. The introduction of the variable “space” into the model allowed us to predict pollen levels in different areas throughout the region. The interpolation method was used to make weekly estimations of Olea pollen values in areas where there was no aerobiological sampling station. In addition, the maps generated present a two-dimensional vision of the study area, showing that bioclimatic diversity of this region promotes a step-wise flowering of Olea.     

Fungi,bacteria and soil pH: the oxalate–carbonate pathway as a model for metabolic interaction

The oxalate–carbonate pathway involves the oxidation of calcium oxalate to low‐magnesium calcite and represents a potential long‐term terrestrial sink for atmospheric CO ₂. In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non‐sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil.     

The aerobiological significance of smut spores in Tulsa,Oklahoma

Few aerobiological studies have focused on smut spores, teliospores of fungi within the order Ustilaginales, but the scientific literature provides evidence of the potential aerobiological significance of these plant pathogens. The atmosphere in Tulsa, Oklahoma was monitored for the presence of smut teliospores using a Burkard Volumetric Spore Trap. Smut spores were identified in the atmospheric samples every day from May to October during 1991 and 1992 at concentrations that were normally below 1000 spores/m³. The peak concentration observed during this study was almost 6000 spores/m³. Daily concentrations fluctuate due to a variety of factors such as precipitation, relative humidity, percent sunshine, and the phenology of fungi in relation to their hosts. In northeastern Oklahoma, the most prevalent species of smuts in the atmosphere during the spring includeSphacelotheca occidentalis, Ustilago tritici, andU. kolleri. In the fall, spores ofU. brumivora, U. bullata, andU. maydis are more common.     

Aerobiological monitoring for fungal spores in a rehabilitation hospital in Northern Italy

In the setting of an aerobiological study of confined environments and environmental prevention of nosocomial infections, aerobiological monitoring of 22 areas in Montescano Medical Rehabilitation Centre (Pavia) was performed in three different months: February, May, and August, 1994. A Lanzoni 3000 spore trap was used for the monitoring. Examination of the results showed that, in the environments monitored, the indoor presence of fungi increased progressively over the three periods considered. The behaviour of individual genera of fungi differed. In the winter periodPenicillium andAspergillus were the most commonly encountered genera.Cladosporium was the dominant genus from the spring to the summer while the yeasts had their maximum counts in the spring morning. The use of air conditioning, combined with the low air exchange between outdoors and indoors in some of the environments certainly played a part in the low concentrations of these latter aerofungi.     

Aerobiological monitoring for fungal spores in a rehabilitation hospital in Northern Italy

In the setting of an aerobiological study of confined environments and environmental prevention of nosocomial infections, aerobiological monitoring of 22 areas in Montescano Medical Rehabilitation Centre (Pavia) was performed in three different months: February, May, and August, 1994. A Lanzoni 3000 spore trap was used for the monitoring. Examination of the results showed that, in the environments monitored, the indoor presence of fungi increased progresively over the three periods considered. The behaviour of individual genera of fungi differed. In the winter periodPenicillium andAspergillus were the most commonly encountered genera,Cladosporium was the dominant genus from the spring to the summer while the yeasts had their maximum counts in the spring morning. The use of air conditioning, combined with the low air exchange between outdoors and andoors in some of the environments certainly played a part in the low concentrations of these latter aerofungi.     

The aerobiological significance of smut spores in Tulsa,Oklahoma

Few aerobiological studies have focused on smut spores, teliospores of fungi within the order Ustilaginales, but the scientific luterature provides evidence of the potential aerobiological significance of these plant pathogens. The atmosphere in Tulsa, Oklahoma was monitored for the presence of smut teliospores using a Burkard Volumetric Spore Trap. Smut spores were identified in the atmospheric samples every day from May to October during 1991 and 1992 at concentrations that were normally below 1000 spores/m³. The peak concentration observed during this study was almost 6000 spores/m³. Daily concentrations fluctuate due to a variety of factors such as precipitation, relative humidity, percent sunshine, and the phenology of fungi in relation to their hosts. In northeastern Oklahoma, the most prevalent species of smuts in the atmosphere during the spring includeSphacelotheca occidentalis, Ustilago tritici, andU. kolleri. In the fall, spores ofU. brumivora, U. bullata, andU. maydis are more common.     

Airborne allergenic microorganisms associated with mushroom cultivation

Exposure to microorganisms, including thermophilic actinomycetes and fungal spores, and to airborne dust produced during compost production and mushroom picking may cause work-related respiratory symptoms. Previous studies have implicated Thermoactinomyces vulgaris and Faenia rectivirgula, the aetiological agents in farmer's lung disease, as causes of these symptoms but these species have been rare in aerobiological studies of mushroom farms. As part of a study of the respiratory health of the exposed workers, we carried out an aerobiological survey of all the stages of commercial mushroom production. Samples of viable airborne microorganisms were collected at a farm from eight locations on two occasions using Andersen cascade impactors. Large numbers of airborne thermophilic actinomycetes, yielding > 10⁶ colony-forming units (cfu) m^?3 air sampled, were associated with compost handling. These were predominantly Thermomonospora spp., while Thermoactinomyces spp. and Faenia rectivirgula were few. Because the compost was largely undisturbed, few airborne actinomycete spores were found in mushroom growing houses, but concentrations of fungal spores exceeded 10⁵ cfu m^?3 when mushrooms were being harvested. Most were Penicillium spp. and Aspergillus fumigatus but Peziza ostracoderma and Trichoderma spp. were also isolated. Workers are thus exposed to a wide range of airborne microorganisms, but the role of many of these in mushroom workers' respiratory symptoms is not yet fully understood.     

Aerobiology in plant protection

Summary The control of phytopathogenic fungi in agriculture requires sometimes excessive chemical treatments because, in many cases, reliable monitoring systems in order to assess the real risk for the cultivations are not available.Therefore, the likelihood to assess the presence and the amount of phytophatogenic fungus propagules in the air with a spore-trap has been investigated in order to evaluate their correlation with the climate and the disease occurrence. Four phytopathogenic fungi, namelyVenturia inequalis, Phytophthora infestans, Cercospora beticola andDiaporthe phaseolorum var.caulivora were taken into consideration.Practical use of airborne spore monitoring in a disease control strategy proved to be useful only forVenturia inequalis andPhytophthora infestans causal agent of apple scab and tomato late blight respectively. For the latter, the utilisation of an aerobiological monitoring system for the disease prediction can be assumed.     

Culturable Fungi of Stored ‘Golden Delicious’ Apple Fruits: A One-Season Comparison Study of Organic and Integrated Production Systems in Switzerland

The effects of organic and integrated production systems on the culturable fungal microflora of stored apple fruits from five matched pairs of certified organic and integrated ‘Golden Delicious’ farms were studied at five representative production sites in Switzerland. Isolated fungi were identified morphologically. Colonization frequency (percentage of apples colonized), abundance (colony numbers), and diversity (taxon richness) were assessed for each orchard. The standard quality of the stored fruits was comparable for both organic and integrated apples and complied with national food hygiene standards. Yeasts (six taxa) and the yeast-like fungus Aureobasidium pullulans were the dominant epiphytes, filamentous fungi (21 taxa) the dominant endophytes. The most common fungi occurred at all sites and belonged to the “white” and “pink” yeasts, yeast-like A. pullulans, filamentous fungi Cladosporium spp., Alternaria spp., and sterile filamentous fungi. Canonical correspondence analysis of the total fungal community revealed a clear differentiation among production systems and sites. Compared to integrated apples, organic apples had significantly higher frequencies of filamentous fungi, abundance of total fungi, and taxon diversity. The effects of the production system on the fungal microflora are most likely due to the different plant protection strategies. The incidence of potential mycotoxin producers such as Penicillium and Alternaria species was not different between production systems. We suggest that higher fungal diversity may generally be associated with organic production and may increase the level of beneficial and antagonistically acting species known for their potential to suppress apple pathogens, which may be an advantage to organic apples, e.g., in respect to natural disease control.     

夏季故宫养心殿空气中真菌的调查与分析

【目的】在无法实现洁净环境的古建筑内,文物易遭受霉菌的破坏,尤其是在闷热的夏季。探明空气中真菌的种类对文物、游客的安全具有重要意义。【方法】采用自然沉降法与撞击法对夏季养心殿正殿内代表性的6个取样位置的气生真菌进行培养并进行ITS1 rDNA序列分析。【结果】利用自然沉降法测得气生真菌22种,以枝孢属(Cladosporium)、曲霉属(Aspergillus)和青霉属(Penicillium)为优势类群,在2个位置(佛堂二层与西暖阁)空气真菌污染超标;而撞击法测得100余种,腐生营养型真菌比例较高,优势类群为链格孢属(Alternaria)、Cladosporium、木霉属 (Trichoderma)、根霉属(Rhizopus)、Aspergillus和Penicillium,所有6个位置均超标。通过对环境因子与真菌多样性的相关性分析发现,养心殿内真菌丰度与温度、湿度及悬浮颗粒物有着密切关系。在相对湿度较低的6月,温度对丰度影响较大;高湿度时,悬浮颗粒物与湿度对真菌丰度影响更大。丝状真菌的丰度与小粒径悬浮颗粒物、相对湿度存在显著正相关,而空气中的酵母菌与温度相关性更高。【结论】本研究对养心殿正殿空气中真菌的种属进行了鉴定,并分析了与环境因子的相关性,为预防、开放展览以及修缮提供了科学依据。     

Diversity and spatial–temporal distribution of airborne fungi at the world culture heritage site Maijishan Grottoes in China

The deposition of the airborne microorganisms onto cultural heritage is associated closely with the subsequent biodeterioration. In this study, a systematic investigation was carried out to detect the seasonal variation and diversity of airborne fungal concentration at the World Cultural Heritage Site Maijishan Grottoes in western China. A bio-aerosol sampler was deployed to collect samples over four seasons in 2016. The culturable airborne fungi were isolated, purified and then identified with the extraction of genomic DNA, PCR amplification of ITS rRNA region, sequencing, and phylogenetic analysis. The concentrations of culturable fungi ranged from 216 to 1389 CFU/m³, which varied seasonally with significant differences among the sampling sites. Fifteen different fungal genera were confirmed, among them, Cladosporium was the most predominant fungal genus, followed by Penicillium. The fungal community structure and their relationship with environmental factors were also delineated. The spatial–temporal differences of airborne fungi at Maijishan Grottoes were mainly due to height, rainfall, relative humidity, and temperature. The dominant genera Cladosporium and Penicillium may pose potential threats to the ancient painted sculptures and murals, and monitoring of the airborne fungi at such a heritage site could provide supporting data for the pre-warning and control of fungal outbreaks inside the caves for better management.

     

麦积山石窟赋存环境中空气细菌的时空分布特征

【目的】空气微生物沉降及污染与文化遗产的微生物退化密切相关,本文对世界文化遗产地麦积山石窟赋存环境空气中细菌浓度和群落结构的季节性变化特征进行了系统研究,为石窟环境监测预警和文物预防性保护提供依据。【方法】利用生物气溶胶采样器,在2016年春、夏、秋和冬季分别采集空气样品;基于传统培养方法获得空气中细菌浓度及纯培养菌株;通过提取基因组DNA、扩增细菌16S rRNA、测序和系统发生树等分子技术研究细菌群落时空动态变化规律;结合环境监测数据,分析影响遗产地空气细菌变化的主要因素。【结果】监测期内,空气细菌浓度在(281.20–1409.20)CFU/m3之间,最高浓度出现在MJ4处的夏季,最低浓度出现在MJO处的春季;具有明显季节性变化特征,在空间层位分布上有所差异,但不显著(P0.05)。培养的细菌菌株经鉴定属于4个门11个属;芽孢杆菌属(Bacillus)、Paenarthrobacter、节杆菌属(Arthrobacter)、薄层菌属(Hymenobacter)和考克氏菌属(Kocuria)等为优势属。【结论】麦积山石窟空气细菌群落结构具有明显的季节性和空间分布动态变化特征;在石窟不同层位,空气中细菌群落分布与相对湿度、温度与降雨量相关;部分细菌种属如芽孢杆菌属、微球菌属(Micrococcus),为壁画及彩塑生物腐蚀的潜在病害菌;麦积山石窟及周边环境空气细菌的监测可为石窟保护和旅游开放管理提供重要参考。     

Ambrosia elatior (L.) in Hungary (1989–1990)

Summary Weeds and among themAmbrosia are probably the most important vascular plants related to pollinosis in Hungary. Sampling was carried out in central (Budapest) and in southern (Paks, Szeged) Hungary. The results of two years (1989–1990) of aerobiological study onAmbrosia airborne pollen are reported. The highest percentage of airborne pollen was found in the mid-August to mid-September period, having a good correlation with clinical data on pollinosis. The implications of these results are considered in the context of forecasting and prevention of seasonal ragweed pollinosis.     

Aerobiological monitoring of the 'Sistine Chapel': airborne bacteria and microfungi trends

The present paper reports the results of a bacteriological and mycological monitoring carried out on the airborne microflora of the Sistine Chapel. The general aim of the study was to evaluate the impact of the flow of visitors, as well seasonal effects, on the qualitative and quantitative variations of microorganisms. Two sampling campaigns were carried out in May and November 1997. A Surface Air System (SAS) sampler (active system) and a sedimentation based sampler (passive system), supported by an original plinth, were used. Temperature, humidity and carbon dioxide were detected. VITEK SYSTEMS jr. for Staphylococcus spp. and microscopic observation for microfungi were the identification methods. In spite of the conditioning and filtration air system, initial results with both samplers, show a positive correlation between the airborne microorganisms and presence and number of visitors. The SAS samples showed higher microbial load, for both bacteria and fungi, than the passive ones, but the epidemiological meaning of the differently collected data varies. The increase during visiting hours of human Staphylococcus spp. is stronger than the airborne bacterial load increase. The microfungi most frequently isolated were Cladosporium spp. and Penicillium spp. These preliminary data underline the significance of the survey for the protection of such a precious environment, and encourage the Authors to continue the ongoing monitoring. This revised version was published online in June 2006 with corrections to the Cover Date.     

A portable sampler (PARTRAP FA 52) for microbiological evaluation of airborne particles: comparison with standard sedimetric and volumetric methods in haemodialysis rooms

Experiments for microbiological evaluation of airborne particles were led in two haemodialysis rooms at the beginning and at the end of activity time (6 h). The efficiency of a new personal and portable aerobiological sampler in comparison with a fixed sampler and a traditional sedimetric method was evaluate. The personal and portable sampler allowed a good evaluation of concentration of bacteria and fungi per cubic metres of sampled air. Since its aspiration flow is equal to Minute Ventilation of an adult; this device provides a quantification of inhaled particles. We propose this device for evaluating the risk for patients and sanitary operators, for monitoring air quality and in implementing adequate environmental prophylaxis and for other applications, e.g. environmental applications.     

天梯山石窟壁画保存环境中空气细菌的季节性变化

【背景】微生物侵蚀是古代壁画常见生物病害,影响壁画的长久保存和安全陈展。空气微生物作为壁画病害菌的主要来源,近年在文物赋存环境监测和预防性保护中引起广泛重视。【目的】对天梯山石窟壁画的2处保存地,即天梯山原址和武威西夏博物馆壁画保存环境中的空气细菌浓度、群落结构及其季节变化规律进行分析。【方法】利用生物气溶胶采样器,在2016年春、夏、秋、冬4季分别采集各位点空气样品;基于传统培养方法获得空气中细菌浓度及纯培养菌株;通过提取细菌基因组DNA、扩增其16S rRNA基因、测序和系统发生关系分析等技术研究不同位点细菌群落时空动态变化规律;结合环境监测数据,分析影响文化遗产地空气细菌群落变化的主要因素。【结果】空气可培养细菌的总浓度在16.7-1 451.8 CFU/m3范围内变动。原址第18窟和第13窟,各季节细菌浓度无显著性差异,且呈明显季节性变动规律,总体特征为夏秋季低,冬春季高。西夏博物馆外空气细菌浓度在各季节均高于库房内,冬季最高。本研究共鉴定出19个细菌属,隶属于4个门;其中不动杆菌属(Acinetobacter)、节杆菌属(Arthrobacter)、芽孢杆菌属(Bacillus)、考克氏菌属(Kocuria)、短波单胞菌属(Brevundimonas)、肉食杆菌属(Carnobacterium)、 Pseudoclavibacter和薄层菌属(Hymenobacter)为优势属。【结论】天梯山石窟空气细菌群落结构具有明显的时空分布特征;相对湿度、温度及季节性降水均会影响其变化;鉴定得到部分种属具备引起壁画生物腐蚀的潜势;本研究可为当地开展遗址和馆藏环境中文物预防性保护提供本底资料。