Natural products obtained from plants with biocidal activity represent an alternative and useful source in the control of biodeterioration of documentary heritage, without negative environmental and human impacts. In this work, we studied the antimicrobial activity of seven essential oils against microorganisms associated with the biodeterioration of documentary heritage. The essential oils were obtained by steam distillation. The antimicrobial activity was analyzed using the agar diffusion method against 4 strains of fungi and 6 bacterial strains isolated from repositories air and documents of the National Archive of the Republic of Cuba and the Historical Archive of the Museum of La Plata, Argentina. Anise and garlic oils showed the best antifungal activity at all concentrations studied, while oregano oil not only was effective against fungi tested but also prevented sporulation of them all. Orange sweet and laurel oils were ineffective against fungi. Clove, garlic, and oregano oils showed the highest antibacterial activity at 25% against Enterobacter agglomerans and Streptomyces sp., while only clove and oregano oils were effective against Bacillus sp. at all concentrations studied. This study has an important implication for the possible use of the natural products from plants in the control of biodeterioration of documentary heritage.

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This study shows that some species of fungi are affected by the magnetic field, which should be taken into account in studies of airborne fungal and air quality. The aim of this paper was to evaluate the effect of the oscillating magnetic field (OMF) on the behavior of colonies of three fungi genus growth in different culture mediums. The stains were: Aspergillus niger, Cladosporium cladosporioides and Penicillium citrinum and were inoculated in 90 mm Petri dishes with: Malt Extract Agar (MEA), Sabouraud Dextrose Agar (SDA) and Czapek-Dox Agar (CDA). Was applied them OMF of 60 Hz/220 V between 1 and 5 mT during 2 h and then they were incubated 7 days to 28 °C. Colonies size (mm) every day was measured. Stimulation in the colonies size of all experimental conditions was showed; the greatest size of A. niger in MEA was notorious. It was demonstrated by statist analyze that only colonies size with 1 mT was significance respect to the control. The effect of OMF on the cellular metabolism was evidenced, as well as: less exudation and major pigmentation of P. citrinum in MEA; variation of pigmentation of A. niger and C. cladosporioides in CDA and increase of conidiogenesis of A. niger in SDA. Was concluded that the applied OMF had a major influence on size colony and mycelia pigmentation of A. niger that C. cladosporioides and P. citrinum, independently of the nutritional state according to the culture medium employed in this study.

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The aim of this work was to analyze the effect of the magnetic field generated by the household appliances on the airborne microbial surrounding these equipment located on indoor environments with particular interest in the environmental fungi. A simultaneous environmental study was carried out in locals of three different geographical places of Havana, Cuba, which have televisions, computers and an electric generator. The air samples were made by a sedimentation method using Malt Extract Agar. The concentration of total aerobic mesophilic as well as fungi and yeasts were determined in rainy and little rainy seasons by applying as factors: exposure time of dishes (5 to 60 min) and distance to the wall (0 and 1 m) at a height of 1 m above the floor. The predominant fungal genera were Cladosporium, Penicillium and Aspergillus. In the dishes that were placed at 0 and 0.5 m from the emitting sources were observed that some bacteria colonies formed inhibition halos, a great diversity of filamentous fungi and an increase in the mycelium pigmentation as well as the pigments excretion. In the rainy season, the highest amounts of fungi were obtained in all samples. In the little rain season the count of the Gram-negative bacilli increased three times the Gram-positive cocci.