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RAPD pattern of isolates of Serpula lacrymans ( eight left- most lanes ) and S. himantioides ( three right-most lanes ) obtained with primer GGACTCCACG. M Marker (kb) (Schmidt and Moreth 1998)
Source publication
Indoor wood-decay fungi cause considerable economical damage. Most of the structural damage to the indoors of buildings in
Europe and North America is caused by brown-rot fungi that degrade conifer wood; white-rot fungi, which preferentially attack
hardwoods, are less common. This review covers the approximately 80 basidiomycetes that commonly occu...
Contexts in source publication
Context 1
... methods applied for the characterization, identification and classification of organisms are independent of subjective judgment and based on objective information (molecules) revealed by the target organism. Consequently, molecular methods have been applied since the 1980s to identify wood-decay fungi and for taxonomical research (Jellison and Goodell 1988; Palfreyman et al. 1988; Schmidt and Kebernik 1989). Some researchers are of the opinion that molecular methods are time-consuming and may lead to incorrect conclusions due to wrongly identified reference fungi or a mixture of fungi in the sample. This is not quite correct. For example, there are commercial laboratories which are able to identify about ten species of indoor wood-decay fungi in samples from buildings within 1 day using the technique of species-specific priming PCR (see below). It is not the intention of this review to describe all of the molecular techniques that are currently used for identifying fungi; instead, an overview of only methods and results that are related to the characterization, identification and phylogeny of indoor wood-decay fungi is provided. Protocols suitable for identifying indoor wood-decay fungi are described in the papers cited. Some fungi that commonly occur on wood used on the outside of buildings and even tree parasites, such as Heterobasidion annosum , have also been found in buildings (see Table 1) and are therefore included below. Among the protein-based techniques, SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) dis- criminates organisms at the species level and below. This technique has been used to distinguish a number of wood- decay fungi (Vigrow et al. 1991a; Palfreyman et al. 1991; Schmidt and Moreth 1995). For example, the closely related Serpula lacrymans and S. himantioides could be distinguished by their respective specific protein banding pattern (Schmidt and Kebernik 1989; Fig. 1). Monokaryons and F 1 dikaryons of S. lacrymans both exhibited the typical species profile. In addition, culture age or medium compo- sition did not cause significant changes in the banding pattern (Schmidt and Moreth-Kebernik 1990). SDS-PAGE is a rapid technique when the sample originates from a pure culture. However, in terms of identifying wood-decay fungi, SDS-PAGE is of little of no practical importance. Isozyme analysis has been used to distinguish closely related species and forms, for investigations on genetic variability and on the spread of pathogens. There are a number of publications on tree parasites, such as Heterobasidion annosum (e.g. Karlsson and Stenlid 1991), but none are available on the common indoor wood-decay fungi. Immunological methods have been performed on several indoor wood-decay fungi, including Coniophora puteana , Gloeophyllum trabeum , Lentinus lepideus , Oligoporus placenta and Serpula lacrymans ( Jellison and Goodell 1988; Palfreyman et al. 1988; Vigrow et al. 1991b; Toft 1993; Clausen 1997). The diagnostic potential lies in the identification of species without the need of a prior isolation and pure culturing and in the detection of fungi at early stages of decay (Clausen and Kartal 2003). However, the experiments often exhibited cross-reactions with non-target organisms, even when monoclonal anti- bodies were used. Immunological methods have also been applied to visualize the distribution of enzymes of wood- degrading fungi within and around the hypha and in woody tissue (Kim et al. 1993). Most investigations on wood-decay fungi use the PCR (e.g. Vainio and Hantula 2000; Hietala et al. 2003; Eikenes et al. 2005). The technique of RAPD (randomly amplified polymorphic DNA) has discriminated wood-decay fungi at different taxonomical levels, namely, isolates, intersterility groups and species. Karjalainen (1996) and La Porta et al. (1997) investigated Heterobasidion annosum . Theodore et al. (1995) showed polymorphism among eight isolates of Serpula lacrymans . Similarity between other S. lacrymans strains (Fig. 2) was found by Schmidt and Moreth (1998). Serpula himantioides (Fig. 2) and Coniophora puteana showed isolate polymorphism. RAPD analysis does not require prior information of the target DNA and is a rapid technique when starting from pure cultures. However, short primers imply an increased sensitivity to contamination. The technique is also unsuited for species identification from unknown samples by comparison, as other, as yet not investigated fungi may by chance share a similar banding pattern. The method, however, is able to identify special isolates of wood-decay fungi, as was impressively shown by Göller and Rudolph (2003): The strain Eberswalde (Ebw) 15 of Coniophora puteana is an obligatory test fungus for evaluating the efficacy of wood preservatives according to the European Standard EN 113 (1996). The strain is known for its variable behaviour in wood-decay tests between different test institutions. RAPD analysis showed that some alleged Ebw 15 cultures held in different test laboratories are actually subcultures from the British facultative test isolate FPRL 11e, thereby explaining the varying test results. The investigation of rDNA (ribosomal DNA) has become popular approach. The conserved rDNA regions 18S and 28S are preferentially used for phylogenetic analyses of genera, families and higher taxonomic groups (e.g. Bresinsky et al. 1999; Jarosch and Besl 2001). The rapidly evolving internal transcribed spacers (ITS 1 and 2) are used for closely related species (see below). The non- transcribed intergenic spacers (IGS 1 and 2), which may be involved in rDNA gene regulation and/or meiotic chromo- some pairing, show the highest intraspecific diversity among all rDNA regions due to length polymorphism (e.g. Guerin-Laguette et al. 2002; Coetzee et al. 2005). Depending on the intention, the RNA genes or the spacers are used for analyses. These domains are either restricted by endonucleases for RFLP (restriction fragment length polymorphism) studies or are sequenced. An RFLP analysis of the IGS has been performed on Heterobasidion annosum (e.g., Kasuga and Mitchelson 2000). Fischer and Wagner (1999) carried out an RFLP analysis of a 5.8S rDNA/ITS II/28S rDNA fragment of 52 lignicolous European polypores and, based on an RFLP analysis, Bao et al. (2004) assignedd 34 Pleurotus strains to biological species. Johannesson and Stenlid (1998) identified H. annosum by comparing its ITS-RFLP profile to reference material, and Zaremski et al. (1999) differentiated single isolates of Coniophora puteana , Gloeophyllum trabeum and Oligoporus placenta using RFLP analysis. Various isolates of the closely related Serpula lacrymans and S. himantioides exhibited distinct fragment profiles after digestion with the restriction endonucleases Hae III/ Taq I (Schmidt and Moreth 1999). Restriction with Taq I differentiated Serpula lacrymans , S. himantioides , Donkioporia expansa , Coniophora puteana , Antrodia vaillantii , Oligoporus placenta and Gloeophyllum sepiarium (Fig. 3). ITS-RFLP analysis is currently a favoured database for the identification of wood-decay and associated fungi (Zaremski et al. 1999; Adair et al. 2002; Diehl et al. 2004; Råberg et al. 2004). This technique has the advantage of being fast and inexpensive. However, the limited ITS size of only 600 – 700 bases prevents a separation of all the approximately 80 fungal species that have been found in buildings. Furthermore, a as yet unanalysed species may feign another fungus by exhibiting similar fragments. Sequencing of rDNA domains avoids the main limitations of RFLP analyses because the complete information of the sequence of the target DNA is obtained. The ITS sequence of a great number of wood-inhabiting fungi is known. The ITS sequence of isolate S7 was in 1999 the first ITS deposition from Serpula lacrymans in the international databases (AJ 245948, Schmidt and Moreth 2000). Table 4 shows the EMBL accession numbers of rDNA-ITS sequences of 18 indoor wood-decay species (Schmidt and Moreth 2002/2003). The list comprises most of the common indoor basidiomycetes. The sizes of the rDNA-ITS sequences, including the ITS 1 and ITS 4 primers of White et al. (1990), range from 625 bp in Gloeophyllum sepiarium to 734 bp in Leucogyrophana pinastri . Intraspecific variation is neglectable, and there is only one variable nucleotide position and a gap among six strains of Serpula lacrymans. A maximum of five variations were found among 17 isolates of Coniophora puteana . Thus, ITS sequences can be used to identify unknown fungal samples through sequence comparison using the Basic Local Alignment Search Tool (BLAST) (e.g. www. ncbi.nlm.nih.gov/blast). BLAST has revealed the ITS- sequence identity of a “ wild ” S. lacrymans isolate from the Himalayas by comparing it with indoor isolates (White et al. 2001), identified misnamed isolates of S. lacrymans (Horisawa et al. 2004), identified Antrodia spp. and Serpula spp. isolations (Högberg and Land 2004) and confirmed Coniophora puteana isolates (Råberg et al. 2004). Partial 28S rDNA sequences were used by Bresinsky et al. (1999) and Jarosch and Besl (2001) for phylogenetic studies on Serpula lacrymans , S. himantioides , Meruliporia incrassata and of Coniophora and Leucogyrophana species. Complete 18S and 28S rDNA sequences are ...
Context 2
... methods applied for the characterization, identification and classification of organisms are independent of subjective judgment and based on objective information (molecules) revealed by the target organism. Consequently, molecular methods have been applied since the 1980s to identify wood-decay fungi and for taxonomical research (Jellison and Goodell 1988; Palfreyman et al. 1988; Schmidt and Kebernik 1989). Some researchers are of the opinion that molecular methods are time-consuming and may lead to incorrect conclusions due to wrongly identified reference fungi or a mixture of fungi in the sample. This is not quite correct. For example, there are commercial laboratories which are able to identify about ten species of indoor wood-decay fungi in samples from buildings within 1 day using the technique of species-specific priming PCR (see below). It is not the intention of this review to describe all of the molecular techniques that are currently used for identifying fungi; instead, an overview of only methods and results that are related to the characterization, identification and phylogeny of indoor wood-decay fungi is provided. Protocols suitable for identifying indoor wood-decay fungi are described in the papers cited. Some fungi that commonly occur on wood used on the outside of buildings and even tree parasites, such as Heterobasidion annosum , have also been found in buildings (see Table 1) and are therefore included below. Among the protein-based techniques, SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) dis- criminates organisms at the species level and below. This technique has been used to distinguish a number of wood- decay fungi (Vigrow et al. 1991a; Palfreyman et al. 1991; Schmidt and Moreth 1995). For example, the closely related Serpula lacrymans and S. himantioides could be distinguished by their respective specific protein banding pattern (Schmidt and Kebernik 1989; Fig. 1). Monokaryons and F 1 dikaryons of S. lacrymans both exhibited the typical species profile. In addition, culture age or medium compo- sition did not cause significant changes in the banding pattern (Schmidt and Moreth-Kebernik 1990). SDS-PAGE is a rapid technique when the sample originates from a pure culture. However, in terms of identifying wood-decay fungi, SDS-PAGE is of little of no practical importance. Isozyme analysis has been used to distinguish closely related species and forms, for investigations on genetic variability and on the spread of pathogens. There are a number of publications on tree parasites, such as Heterobasidion annosum (e.g. Karlsson and Stenlid 1991), but none are available on the common indoor wood-decay fungi. Immunological methods have been performed on several indoor wood-decay fungi, including Coniophora puteana , Gloeophyllum trabeum , Lentinus lepideus , Oligoporus placenta and Serpula lacrymans ( Jellison and Goodell 1988; Palfreyman et al. 1988; Vigrow et al. 1991b; Toft 1993; Clausen 1997). The diagnostic potential lies in the identification of species without the need of a prior isolation and pure culturing and in the detection of fungi at early stages of decay (Clausen and Kartal 2003). However, the experiments often exhibited cross-reactions with non-target organisms, even when monoclonal anti- bodies were used. Immunological methods have also been applied to visualize the distribution of enzymes of wood- degrading fungi within and around the hypha and in woody tissue (Kim et al. 1993). Most investigations on wood-decay fungi use the PCR (e.g. Vainio and Hantula 2000; Hietala et al. 2003; Eikenes et al. 2005). The technique of RAPD (randomly amplified polymorphic DNA) has discriminated wood-decay fungi at different taxonomical levels, namely, isolates, intersterility groups and species. Karjalainen (1996) and La Porta et al. (1997) investigated Heterobasidion annosum . Theodore et al. (1995) showed polymorphism among eight isolates of Serpula lacrymans . Similarity between other S. lacrymans strains (Fig. 2) was found by Schmidt and Moreth (1998). Serpula himantioides (Fig. 2) and Coniophora puteana showed isolate polymorphism. RAPD analysis does not require prior information of the target DNA and is a rapid technique when starting from pure cultures. However, short primers imply an increased sensitivity to contamination. The technique is also unsuited for species identification from unknown samples by comparison, as other, as yet not investigated fungi may by chance share a similar banding pattern. The method, however, is able to identify special isolates of wood-decay fungi, as was impressively shown by Göller and Rudolph (2003): The strain Eberswalde (Ebw) 15 of Coniophora puteana is an obligatory test fungus for evaluating the efficacy of wood preservatives according to the European Standard EN 113 (1996). The strain is known for its variable behaviour in wood-decay tests between different test institutions. RAPD analysis showed that some alleged Ebw 15 cultures held in different test laboratories are actually subcultures from the British facultative test isolate FPRL 11e, thereby explaining the varying test results. The investigation of rDNA (ribosomal DNA) has become popular approach. The conserved rDNA regions 18S and 28S are preferentially used for phylogenetic analyses of genera, families and higher taxonomic groups (e.g. Bresinsky et al. 1999; Jarosch and Besl 2001). The rapidly evolving internal transcribed spacers (ITS 1 and 2) are used for closely related species (see below). The non- transcribed intergenic spacers (IGS 1 and 2), which may be involved in rDNA gene regulation and/or meiotic chromo- some pairing, show the highest intraspecific diversity among all rDNA regions due to length polymorphism (e.g. Guerin-Laguette et al. 2002; Coetzee et al. 2005). Depending on the intention, the RNA genes or the spacers are used for analyses. These domains are either restricted by endonucleases for RFLP (restriction fragment length polymorphism) studies or are sequenced. An RFLP analysis of the IGS has been performed on Heterobasidion annosum (e.g., Kasuga and Mitchelson 2000). Fischer and Wagner (1999) carried out an RFLP analysis of a 5.8S rDNA/ITS II/28S rDNA fragment of 52 lignicolous European polypores and, based on an RFLP analysis, Bao et al. (2004) assignedd 34 Pleurotus strains to biological species. Johannesson and Stenlid (1998) identified H. annosum by comparing its ITS-RFLP profile to reference material, and Zaremski et al. (1999) differentiated single isolates of Coniophora puteana , Gloeophyllum trabeum and Oligoporus placenta using RFLP analysis. Various isolates of the closely related Serpula lacrymans and S. himantioides exhibited distinct fragment profiles after digestion with the restriction endonucleases Hae III/ Taq I (Schmidt and Moreth 1999). Restriction with Taq I differentiated Serpula lacrymans , S. himantioides , Donkioporia expansa , Coniophora puteana , Antrodia vaillantii , Oligoporus placenta and Gloeophyllum sepiarium (Fig. 3). ITS-RFLP analysis is currently a favoured database for the identification of wood-decay and associated fungi (Zaremski et al. 1999; Adair et al. 2002; Diehl et al. 2004; Råberg et al. 2004). This technique has the advantage of being fast and inexpensive. However, the limited ITS size of only 600 – 700 bases prevents a separation of all the approximately 80 fungal species that have been found in buildings. Furthermore, a as yet unanalysed species may feign another fungus by exhibiting similar fragments. Sequencing of rDNA domains avoids the main limitations of RFLP analyses because the complete information of the sequence of the target DNA is obtained. The ITS sequence of a great number of wood-inhabiting fungi is known. The ITS sequence of isolate S7 was in 1999 the first ITS deposition from Serpula lacrymans in the international databases (AJ 245948, Schmidt and Moreth 2000). Table 4 shows the EMBL accession numbers of rDNA-ITS sequences of 18 indoor wood-decay species (Schmidt and Moreth 2002/2003). The list comprises most of the common indoor basidiomycetes. The sizes of the rDNA-ITS sequences, including the ITS 1 and ITS 4 primers of White et al. (1990), range from 625 bp in Gloeophyllum sepiarium to 734 bp in Leucogyrophana pinastri . Intraspecific variation is neglectable, and there is only one variable nucleotide position and a gap among six strains of Serpula lacrymans. A maximum of five variations were found among 17 isolates of Coniophora puteana . Thus, ITS sequences can be used to identify unknown fungal samples through sequence comparison using the Basic Local Alignment Search Tool (BLAST) (e.g. www. ncbi.nlm.nih.gov/blast). BLAST has revealed the ITS- sequence identity of a “ wild ” S. lacrymans isolate from the Himalayas by comparing it with indoor isolates (White et al. 2001), identified misnamed isolates of S. lacrymans (Horisawa et al. 2004), identified Antrodia spp. and Serpula spp. isolations (Högberg and Land 2004) and confirmed Coniophora puteana isolates (Råberg et al. 2004). Partial 28S rDNA sequences were used by Bresinsky et al. (1999) and Jarosch and Besl (2001) for phylogenetic studies on Serpula lacrymans , S. himantioides , Meruliporia incrassata and of Coniophora and Leucogyrophana species. Complete 18S and 28S rDNA sequences are ...
Citations
... Among the causes of wood deterioration, decay caused by brown rot fungi significantly degrades wood members. For example, most indoor structural damage in North American buildings is caused by brown rot fungi [4], and it is estimated that about 80% of decay is caused by brown rot fungi [5]. Moisture intrusion, which is necessary to promote decay, has also been reported to affect the shear performance of wood joints [6]. ...
To enable the long-term use of existing wooden structures, appropriately evaluating the extent of damage of the biodeterioration of structural performance, including members and joint systems, is necessary. To give one example, accurately estimating the single shear strength performance of nail and screw joints with decay is crucial. Therefore, this study proposes a method to model this by dividing wood into multiple layers with different strength performance, considering the grade of deterioration in a cross-section of decayed wood. The model was used to differentiate the sound layer and three decayed layers (multilayer) according to the extent of the damage. The estimated values, which were produced using the proposed model, were compared to the single shear strength of screw and nail joints with decay using two species of wood, namely Abies sachalinensis (Todomatsu) and Cryptomeria japonica (Sugi). The results point to a good fit between the average value of the experimental results and the estimated values of the proposed model. Compared with the existing (single-layer) model, the proposed model improved the accuracy of estimating the strength of wood undergoing early deterioration and therefore was considered usable.
... The moisture content of the bamboo samples was found to range from 25 % to 98 %, which is generally suitable for fungal degradation. The availability of moisture is a prerequisite for fungal degradation, and exclusion of moisture can be used as a protection method (Schmidt, 2007). Different moisture content ranges have been reported as suitable for fungal (Candelier et al. 2017;Schmidt et al. 2020;Thybring et al. 2018). ...
... Different moisture content ranges have been reported as suitable for fungal (Candelier et al. 2017;Schmidt et al. 2020;Thybring et al. 2018). Even with moisture as a factor that influences fungal degradation, some studies have reported fungal degradation by C. puteana at 22 % which is below fiber saturation point (Schmidt, 2007). Table 4, shows that samples treated with CLS showed hyphal coverage of 30-85 %, scoring between 1 and 3, while those treated with BBA had coverage of 0-37 % with a score of 0-2. ...
This study compared the effectiveness of crude lake salt, a traditional preservative used by artisans in Uganda, and borax-boric acid, a conventional preservative, against fungal degradation. Using the European standard, an experiment was set up to determine the durability of Oxytenanthera abyssinica, Oldeania alpina and Bambusa vulgaris treated with 2 % and 6 % crude lake salt and borax-boric acid against Gloeophyllum trabeum, Coniophora puteana and Trametes versicolor. Mass loss comparisons between treated and untreated bamboo samples were made. Durability classes were assigned according to the amount of mass lost. Bamboo samples exposed to G. trabeum had lower surface hyphal coverage compared to those exposed to C. puteana and T. versicolor irrespective of the preservative used. Samples treated with borax-boric acid were in durability class I compared to those treated with crude lake salt that were between class II and III according to European standard. The lowest mass loss for bamboo treated with crude lake salt was 5.9 % in O. abyssinica exposed to G. trabeum. The highest mass loss for bamboo treated with crude lake salt was 14.24 % in B. vulgaris exposed to T. Versicolor. The study confirmed that while artisans use crude lake salt as a traditional preservative, it does not protect against white and brown rot while all concentrations of borax-boric acid provided protection against all fungi.
... Indeed, water provides the necessary environment for fungal growth, enabling hyphal penetration into wood structures and also allowing extracellular transport of fungal metabolites [18,150]. Moisture activates enzymatic processes in fungi, but it is also essential in non-enzymatic reactions involving hydrogen peroxide influencing the overall decay process [24]. ...
Wooden Cultural Heritage (WCH) represents a significant portion of the world's historical and artistic heritage, consisting of immovable and movable artefacts. Despite the expertise developed since ancient times to enhance its durability, wooden artefacts are inevitably prone to degradation. Fungi play a pivotal role in the deterioration of WCH in terrestrial ecosystems, accelerating its decay and leading to alterations in color and strength. Reviewing the literature of the last 25 years, we aimed to provide a comprehensive overview of fungal diversity affecting WCH, the biochemical processes involved in wood decay, and the diagnostic tools available for fungal identification and damage evaluation. Climatic conditions influence the occurrence of fungal species in threatened WCH, characterized by a prevalence of wood-rot fungi (e.g., Serpula lacrymans, Coniophora puteana) in architectural heritage in temperate and continental climates and Ascomycota in indoor and harsh environments. More efforts are needed to address the knowledge fragmentation concerning biodiversity, the biology of the fungi involved, and succession in the degradative process, which is frequently centered solely on the main actors. Multidisciplinary collaboration among engineers, restorers, and life sciences scientists is vital for tackling the challenges posed by climate change with increased awareness. Traditional microbiology and culture collections are fundamental in laying solid foundations for a more comprehensive interpretation of big data.
... Decay probability and decay rate depend on many factors, amongst them the wood species used, climate conditions, and construction details. In studies from Northern Europe and the USA brown rot fungi account for 73-85 % of fungal decay damages in wood structures (Alfredsen et al. 2005;Duncan and Lombard 1965;Schmidt 2007;Viitanen and Ritschkoff 1991). A reason for this is the extensive use of coniferous timber, which is more susceptible to brown rot decay. ...
Phenol-formaldehyde (PF) resins can be impregnated and cured in situ to improve the woods dimensional stability and decay resistance. In search of renewable alternatives, the substitution of phenol by lignin cleavage products (LCP) has been discussed. However, the different chemical nature may affect the performance of the resin against fungal decay, formaldehyde emission, and equilibrium moisture content. In this study, 30 % (w/w) of the phenol in PF resins were substituted by LCP obtained from microwave-assisted pyrolysis. Scots pine sapwood was modified with the resin. The decay resistance against Rhodonia placenta, Gloeophyllum trabeum , and Trametes versicolor was determined. Additionally, effects of specimen organisation within the Petri dish, different substrates, length of leaching, and type of inoculum were studied. Further, the materials water vapor sorption properties and formaldehyde emission were determined. All modifications effectively reduced fungal decay. With 10 % weight percent gain (WPG), initial decay was detected, while 20 % WPG and 30 % WPG provided efficient protection. The substitution of phenol increases the formaldehyde emission. While further reduction in formaldehyde in the resin admixture or formaldehyde scavengers may be required, the method described herein can be used to partly replace fossil-based phenol, while maintaining good fungal resistance.
... In the last decades, the total number of appearances of basidiomycete in buildings in Europe () mainly corresponded to S. lacrymans and C. puteana, except in Norway, where Antrodia was the most frequent genus [24,25]. ...
... These conditions were not possible for this study due to the availability of access. According to Jenning et al. [25], under field conditions, most sporophores (which play a role in the development of the mycelium) are produced in spring and autumn, and the case study was in spring. However, the fructification (fruitful body) could take place in winter and, to a lesser extent, in summer, according to the predominant temperatures, so this study could be applied to observe the development of the mycelium of the fungus even in spring if environmental conditions are met for its growth. ...
High moisture content, low ventilation levels, and changes in the hygrothermal design of wooden dwellings could generate environmental conditions favorable for developing the rot fungus Serpula lacrymans, which is known as the most destructive fungus of its kind. The purpose of this research was to develop an experimental methodology to determine the conditions of the appearance of the fungus S. lacrymans, through in situ measurement of biological and environmental frequency indicators for wooden dwellings in South Central Chile. The referential standards for the appearance of the fungus were determined based on specialized literature and measurements of dwellings with and without deterioration. The frequency indicators for the appearance of the fungus defined and studied were as follows: frequency of air temperature FATs (%), frequency of relative humidity FRMs (%), frequency of ventilation rate FVRs (%), and rot fungus spore concentrations (CFU/pp). The methodology was validated by being measured in various enclosures and spaces under the floor in wooden dwellings in the cities of Valdivia and Temuco. The results confirmed the strong relationship between environmental relative humidity frequencies, ventilation levels, and spore concentration regarding the appearance of the fungus, where the growth dynamics cannot be separately explained without a previous analysis of the variables. In general, the dwellings most affected by the presence of the fungus had the greatest moisture levels, lower ventilation levels, and greater spore concentration. This study is the basis to diagnose the phenomena of the appearance of the rot fungus in wooden dwellings in climates favorable for its development.
... Brown rot fungi constitute a rather small amount of the total number of wood rotting basidiomycetes, less than 10% in Europe (Ryvarden and Gilbertson, 1993) and 7% in North America (Gilbertson and Ryvarden, 1986). However, brown-rot fungi account for 73-85% of fungal decay cases in wood structures in Northern Europe and the USA (Alfredsen et al., 2005;Duncan and Lombard, 1965;Schmidt, 2007;Viitanen and Ritschkoff, 1991). ...
... Brown rot fungi constitute a rather small amount of the total number of wood rotting basidiomycetes, less than 10% in Europe (Ryvarden and Gilbertson, 1993) and 7% in North America (Gilbertson and Ryvarden, 1986). However, brown-rot fungi account for 73-85% of fungal decay cases in wood structures in Northern Europe and the USA (Alfredsen et al., 2005;Duncan and Lombard, 1965;Schmidt, 2007;Viitanen and Ritschkoff, 1991). Further, brown-rot fungi pose a higher risk to wooden structures than white rot fungi because they can cause substantial strength reduction even at relatively low levels of mass loss, i.e., resulting in greater damage within a shorter period (Wilcox, 1978;Winandy and Morrell, 1993). ...
After fungal decay experiments, chemical characterisation of the wood is often a routine and several methodological approaches are available. In this study, we tested if simultaneous thermal analysis (STA) is a valid alternative to traditional wet chemical methods since STA allows significantly smaller sample size and faster analysis. Three model fungi including the brown rot fungi Rhodonia placenta and Gloeophyllum trabeum and the white rot fungus Trametes versicolor were employed in the study using Norway spruce as substrate. The experiment was harvested after 10, 20 and 52 weeks. At each harvest interval, aliquots of the material were characterized by STA and wet chemical methods. The results validated that STA can be effectively used to estimate cell wall composition of brown rot depolymerised wood. However, STA slightly overestimated cellulose at brown rot decay above 50%. The method was not verified for simultaneous white rot because STA only estimated hemicellulose correctly compared to the wet chemical method. Hence, STA is considered suitable for brown rot fungi below 50% mass loss but not for simultaneous white rot because STA did not estimate cellulose and lignin correctly.
... Several of the top relatively abundant genera identified in this study are associated with building and occupant health. For example, fungal species of Antrodia, and Heterobasidion are key house-rot fungi, as they decay wooden building materials (Huckfeldt & Schmidt, 2006;Schmidt, 2007;Schmidt & Huckfeldt, 2011;Gabriel & Švec, 2017;Haas et al., 2019). Sarocladium species are associated with problems in biodegradation of mineral-based materials (Ponizovskaya et al., 2019). ...
Humans are exposed to diverse communities of microbes every day. With more time spent indoors by humans, investigations into the communities of microbes inhabiting occupied spaces have become important to deduce the impacts of these microbes on human health and building health. Studies so far have given considerable insight into the communities of the indoor microbiota humans interact with, but mainly focus on sampling surfaces or indoor dust from filters. Beneath the surfaces though, building envelopes have the potential to contain environments that would support the growth of microbial communities. But due to design choices and distance from ground moisture, for example, the temperature and humidity across a building will vary and cause environmental gradients. These microenvironments could then influence the composition of the microbial communities within the walls. Here we present a case study designed to quantify any patterns in the compositions of fungal and bacterial communities existing in a building envelope and determine some of the key variables, such as cardinal direction, distance from floor or distance from wall joinings, that may influence any microbial community composition variation. By drilling small holes across walls of a house, we extracted microbes onto air filters and conducted amplicon sequencing. We found sampling height (distance from the floor) and cardinal direction the wall was facing caused differences in the diversity of the microbial communities, showing that patterns in the microbial composition will be dependent on sampling location within the building. By sampling beneath the surfaces, our approach provides a more complete picture of the microbial condition of a building environment, with the significant variation in community composition demonstrating a potential sampling bias if multiple sampling locations across a building are not considered. By identifying features of the built environment that promote/retard microbial growth, improvements to building designs can be made to achieve overall healthier occupied spaces.
... Environmental factors such as UV radiation, moisture, insects, fungi, and other microorganisms play a particularly important role in wood degradation [1]. The natural degradation mechanisms by living organisms can be easily reduced in a targeted manner by means of moisture content regulation [2]. However, the influence of UV radiation cannot be so easily avoided and is a consistent agent of deterioration, especially as wood is commonly used in visible areas exposed to sunlight. ...
... where m 0 is the dry mass (u = 0%) of the wood sample prior treatment and m ui is the wet mass of the wood sample after impregnation. Formula (2). Material uptake ...
As biological material, wood is distinctly affected by to various environmental influences during use. Reductions in durability can come from ultraviolet (UV) radiation, insects, fungi, and microorganisms in both exterior and interior applications. Wood can be easily protected from living organisms via the control of moisture content; however, UV radiation is not so easily managed. Wood components subject to this degradation are damaged and decomposed at a molecular level leading to deterioration of surface quality, especially in visible application areas. A potential remedy to this is using the UV-stabilizing properties of zinc oxide nanoparticles. Zinc oxide nano-dispersions based on propylene glycol (PG) were introduced into the microscopic structure of fir (Abies alba) and beech (Fagus sylvatica) wood by whole-cell impregnation to overcome problems associated with surface coatings. In this work the material uptake of ZnO nano-dispersions in concentrations of 1%, 2%, and 3% w/v were investigated and their effect on the stability of the optical appearance to UV exposure in short-term weathering were evaluated. Untreated reference samples showed significant photo-yellowing. A 1% w/v ZnO dispersion significantly increased the UV stability of treated surfaces. It was found that the uptake of the nano-dispersions was independent of the proportion of ZnO, and that the impregnating agents penetrated fir wood (about 200%) stronger than beech wood (about 70%). Already, a 2% w/v ZnO nano-dispersion led to a saturation of ZnO in the cell structure of the treated wood, for fir as well as beech, and no further ZnO uptake was achieved with 3% w/v nano-dispersions. Scanning electron microscopy shows an agglomeration of ZnO-NP in the cellular pathways impacting penetration, reducing leachability at higher concentrations.
... These included Armillaria sp., Bjerkandera sp., Ganoderma resinaceum Murrill, Hyphodermella sp., Junghuhnia nitida (Pers.) Ryvarden, a Phanerochaetaceae fungus, Phlebia sp., Sistotrema sp., Stereum sp., and Trametes versicolor (L.) Lloyd [50][51][52][53][54][55][56][57]. Trechispora nivea (Pers.) ...
... K. H. Larss. was the only brown-rot decay fungus isolated from the samples [52]. Other basidiomycetes isolated were Burgella sp., Byssomerulius corium (Pers.) ...
Photoactive nanoparticles are used to reduce microbial colonization and self-clean surfaces of materials such as glass and ceramics. To test whether such an approach is feasible for wood surfaces, we treated radiata pine samples with TiO 2 (rutile and anatase) or ZnO nanoparticles and then coated the samples with different finishes. Coated samples and uncoated controls were exposed outdoors for six months. After exposure, fungi colonizing wood surfaces were identified using molecular techniques and microscopy, and colour changes in the wood samples were also measured. Treatment of uncoated surfaces with nanoparticles reduced the discolouration of wood during weathering but had little effect on colonization of wood by black mould fungi. In contrast, pretreatment of samples with titanium dioxide nanoparticles increased the number and diversity of fungi including basidiomycetes colonizing coated samples, whereas zinc oxide nanoparticles had the opposite effect. Zinc oxide nanoparticles, however, were less effective than rutile titanium dioxide nanoparticles at reducing the discolouration of coated samples exposed to natural weathering. We conclude that none of the photoactive nanoparticles on their own are able to reduce microbial colonization and discoloration of samples. This suggests that it may be difficult to create self-cleaning wood surfaces using photoactive nanoparticles.
... Our results showed a similarity of the fungal community structure within the study areas in managed forest as well as in unmanaged forest with different amount of deadwood, because no clear clusters emerged, only unmanaged and manged sites (Fig. 2). Table 1 were not pointed out and indicated as black dots) Forest management practices affect the mycobiota and could cause decreases in abundance and diversity of wood-inhabiting fungi [23] or may have no effect [8,14,21]. Our observations on diversity of fungi agree with results of numerous studies [8,14,19,[22][23][24] recorded reduction of species in managed forests than in unmanaged ones, and less fungal diversity in thinned broadleaved forests than in non-thinned ones. Decrease in diversity of wood-decay fungi in the managed stand seems to have resulted from reduction in available deadwood volume and woody debris that is common and has been reported previously [8,14,18,24]. ...
