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Several interesting fungal strains were recovered from air and surface samplings in a number of Paleolithic-decorated caves in France during multiple surveys. Multi-locus (ITS, LSU, SSU, RPB1, RPB2 and TEF-1α) phylogenetic analysis of these strains through maximum likelihood and Bayesian inference coupled with a morphological characterization revealed a new fungal taxa, Leptobacillium cavernicola sp. nov. This new species morphologically and phylogenetically close to Leptobacillium muralicoa, which was also first isolated from a cultural heritage context. The study of this new species led us to reconsider the taxonomic position of strains that have hitherto been identified as Leptobacillium spp., suggesting that several new species could be added to the genus.

Leptobacillium cavernicola Leplat, sp. nov. MB844042 (Fig. 3) GenBank: OM622527 (ITS), OM628786 (LSU), OM628847 (SSU), OM677786 (RPB1), OM654326 (RPB2), OM654337 (TEF1-α) Systematic position: Fungi, Dikarya, Ascomycota, Pezizomycotina, Sordariomycetes, Hypocreomycetidae, Hypocreales, Cordycipitaceae Holotype:— FRANCE. Prignac-et-Marcamps, 45° 2’ 20” N, 0° 30’ 6” W, 22 October 2018. Isolated from surface sampling in the Pair-non-Pair cave, CBS 149113, preserved in a metabolically inactive state. Etymology: The epithet cavernicola refers to the environment from which the strains of the species were mainly isolated, i.e. caves. Colonies on MEA reached 12–24 mm diam. after 14 days at 25 °C, aerial mycelium can be scarce, velvety, white, slightly yellow exudate present in some strains. Reverse dark brown. Colonies on PDA reached 14–20 mm diam. after 14 days at 25 °C, aerial mycelium can be scarce, velvety to floccose, white. Reverse usually dark brown. Yellow diffusible pigment present in some strains. Phialides 5.1–27.2 x 1.2 –1.7 µm, mainly solitary, slender, tapering toward tip. Conidia 3.1–6.9 x 0.9 –1.5 µm, forming long, slender chains, narrowly cylindrical to slightly fusiform, some were slightly lemon-shaped, first-formed conidium were usually shorter, obovoid to pyriform with a rounded distal end. Chlamydospore absent. Octahedral crystals not observed. Other strains examined:— FRANCE. LRMH C212, LRMH C216, LRMH C302, LRMH C304, Cabrerets, 44° 30′ 27″ N, 1°38′ 40″ E, isolated from air samplings in Pech-Merle cave, LRMH C212 and LRMH C 216 in October 2016, LRMH C302 and LRMH C 304 in October 2018; LRMH C217, Prignac-et-Marcamps, 45° 2’ 20” N, 0° 30’ 6” W, October 2016, isolated from air sampling in Pair-non-Pair cave; LRMH C313, LRMH C314, Les Eyzies-de-Taillac-Sireuil, 44° 56′ 37″ N, 1° 02′ 32″ E, October 2018, isolated from air samplings in Combarelles cave. Notes: Leptobacillium cavernicola is distinguishable in the genus Leptobacillium by its slow growth rate on PDA at 25 °C, which is comparable to the rates recorded for L. leptobactrum var. leptobactrum and L. muralicola. However, caution should be applied when comparing with L. muralicola due to the differences in experimental protocol: Sun et al. (2019) studied the growth rate of this fungus at 20 °C over 10 days. The phialides produced by L. cavernicola seem shorter than those produced by L. leptobactrum var. leptobactrum and L. muralicola, and the difference between these three species is significantly supported by the phylogenetic data. The dark brown reverse of L. cavernicola on MEA and PDA media also seems to be characteristic of the species.

An original fungal strain has been recovered during an aerobiological survey in the Pech-Merle show cave (France). The use of multi-locus (ITS, LSU, SSU RPB1, RPB2 and TEF-1α) phylogenetic analysis of the strain by maximum likelihood and by Bayesian inference coupled with a morphological characterization allowed us to place it in the Simplicillium genus as Simplicillium pech-merlensis sp. nov. This new species seems morphologically close to S. calcicola and S. album, which were also first isolated from a cave habitat. This paper discusses the phylogenetic place of S. pech-merlensis and some other species in the genus Simplicillium.

L’étude et la restauration de la sculpture de la Vierge à l’Enfant du musée Sainte-Croix de Poitiers a été l’occasion d’appliquer une méthode innovante de traitement des micro- organismes chlorophylliens : l’exposition aux rayons UV-C. L’œuvre en pierre calcaire, possédant encore des traces de polychromie, avait été conservée en extérieur et était colonisée par les algues, mousses et lichens. La problématique du nettoyage de ces micro-organismes a entraîné une étude technico-scientifique menée au Laboratoire de Recherche des Monuments Historiques. L’exposition sous rayons UV-C, nocifs pour les organismes vivants, présentait l’intérêt d’éviter l’utilisation d’un produit biocide. Les bons résultats de l’étude ont permis d’appliquer cette technique sur la Vierge à l’Enfant, une première dans le domaine de la restauration de sculpture en pierre. The study and restoration of the sculpture of the Virgin and Child in the Musée Sainte-Croix, Poitiers, provided an occasion to apply an innovative method of treatment for chlorophylian microorganisms: exposure to UVC rays. The limestone work, which still bears traces of polychromy, had been kept outside and invaded by algae, moss and lichens. Problems related to cleaning these microorganisms led to a technico-scientific study conducted at the Laboratoire de Recherche des Monuments Historiques (LRMH). Exposure to UVC rays, which have a harmful effect on living organisms, proved of interest because it avoided the use of a biocidal product. The positive results of the study enabled this technique to be applied to the Virgin and Child, a first in the field of restoration of stone sculpture.

Algal proliferation has commonly been reported to occur on monuments, such as crypts, churches, and caves, as soon as artificial lighting is used. In this work we study the effects of UV–C irradiation on algae collected in different caves in Dordogne (southwest of France). First, the effect of UV–C irradiation was tested on algal cell suspensions during increasing exposure times. After treatment, the photosynthetic capacity was assayed using a polarometric method, and algal cell viability was then estimated using a Trypan blue test after a rest period of 15 h. UV–C irradiation was then studied on algal cells cultivated on a solid support consisting of pieces of calcareous stone. Drops of concentrated algal cells were inoculated on stone and exposed to UV–C radiation for 3, 6, or 9 h. After this irradiation, half of the samples were submitted to a high white light intensity (1400 μmol m−2 s−1 of photosynthetically active radiation, PAR) for 6 h while the other half were incubated in the culture room. Subsequently, algal macroscopic parameters such as covering rate and colonized area were measured by macro photography. Both experiments led to the conclusion that UV–C irradiation has deleterious effects on photosynthetic parameters and growth of algal cells.

In the conservation field of buildings, historical monuments and subterranean environments, very few studies highlight the importance to find alternative methods to chemical products against algal biofilm proliferation. Indeed, biofouling by microorganisms is a well-known biodeterioration phenomenon. Algae are considered as pioneers in the biodeterioration of stone, and that's why they are subject to a special interest in this chapter. Conservators of monuments or art works used many chemical applications to prevent or to control the algal proliferation on stone. But, due to the changes in European standards on their use, the chemical products must be replaced by environmentally friendly processes. The ultraviolet irradiation appeared to be a suitable process to control algal proliferation in these environments. Firstly in this chapter, we describe the problematic of algal biofilms (proliferation and biodeterioration) on different substrata and also the effects of applied chemical treatments. Secondly, we define and characterize the UV light and its effects on living organisms. Finally, we present the experimental design and the obtained results on algae harvested in caves at the cellular and molecular scales (pigment contents, photosynthetic activity, DNA damages...) and at the biofilm scale (proliferation measurements). This study shows that the UV treatment can be used as a conservation tool to eradicate algal biofilms which proliferate in buildings and monuments.

This study involves two distinct parts. In the first part, we have studied the chemical modification of quatemary ammonium salts in wood and the preservation of wood against attack by fungi. The modified and the unmodified quaternary ammonium salts show the same biological activity in an artificial medium.The blocks of wood, impregnated with modified and unmodified salts, show that the modification is very beneficial. We have noted that the retention of modified ammonium in the wood is twice than in wood treated with unmodified ammonium.The results obtained in the impregnation test of wood are confirmed by transmission electron microscopy (TEM) coupled with an Electron Energy Loss Spectrometry (EELS). The modification of the chemical structure of ammonium salts allows an increase of the azote rate in wood (44,4 %).The modified ammonium in the cellular cavity level has been observed by the Scanning Electron Microscopy (SEM). The results we found in the biological wood resistance are very interesting. We have also found, for example, that a 1 % concentration of a quaternary ammonium salts preserves wood from the attack of Coriolus versicolor and Poria placenta. The last part is devoted to the study of the ability of modified sawdusts with fatty acids to protect wood. Interesting results are obtained in this area., L étude présentée comporte deux parties distinctes qui ont le même objectif. La première partie s'intéresse à la modification de la structure chimique des sels d'ammonium quaternaire à chaînes grasses. Les essais en boite de pétri montrent que les sels modifiés ont une activité fongicide comparable à celle des sels de départ. Les essais d'imprégnation montrent que, la modification de la structure chimique des sels est très bénéfique. Nous constatons que la rétention des sels modifiés au sein du bois a doublé. Les analyses au M.E.T. nous ont permis de confirmer les résultats obtenus aux essais d'imprégnations. La modification de la structure chimique du sel d'ammonium permet d'augmenter le taux d'azote dans le bois de 44,4%, d'où une augmentation du sel d'ammonium retenu par le bois. Les analyses au M.E.B. ont permis de localiser le sel d'ammonium modifié au niveau des cavités cellulaires, alors qu'il nous était difficile de visualiser le sel d'ammonium soluble. Les résultats que nous avons obtenus dans les essais mycologiques sur bois, constituent un point très positif dans le cadre des objectifs que nous nous sommes fixés à savoir la minimisation de la proportion du sel lessivé tout en gardant intact l'activité fongicide de ces derniers. La dernière partie a consisté à étudier le comportement biologique de la sciure d'Epicéa commun modifiée par des motifs acyles gras à longue chaîne carbonée face au Poria placenta. Nous avons démontré que le bois modifié et exposé au Poria placenta pendant 7, 14 et 21 jours en présence ou en absence de glucose, reste intacte, en particulier au niveau des greffages. Ce résultat très intéressant, peut apporter une réponse aux problèmes poser par la stabilité du matériau bois, et en même temps pour le préserver contre l'attaque du Poria placenta.