Aesthetic Alteration of Marble Surfaces Caused by Biofilm Formation: Effects of Chemical Cleaning

Despite the massive presence of biofilms causing aesthetic alteration to the facade of the Monza Cathedral, our team in a previous work proved that the biocolonization was not a primary damaging factor if compared to chemical-physical deterioration due to the impact of air pollution. Nonetheless, the conservators tried to remove the sessile dwelling microorganisms to reduce discolouration. In this research, two nearby sculpted leaves made of Candoglia marble were selected to study the effects of a chemical treatment combining the biocides benzalkonium chloride, hydrogen peroxide and Algophase\uae and mechanical cleaning procedures. One leaf was cleaned with the biocides and mechanically, and the other was left untreated as control. The impact of the treatment was investigated after 1 month from the cleaning by digital microscopy, environmental scanning electron microscopy, confocal microscopy and molecular methods to determine the composition and the functional profiles of the bacterial communities. Despite the acceptable aesthetic results obtained, the overall cleaning treatment was only partially effective in removing the biofilm from the colonized surfaces and, therefore, not adequately suitable for the specific substrate. Furthermore, the cleaning process selected microorganisms potentially more resistant to biocides so that the efficacy of future re-treatment by antimicrobial agents could be negatively affected

Investigating the microbial community of Cacopsylla spp. as potential factor in vector competence of phytoplasma

Phytoplasmas are obligatory intracellular bacteria that colonize the phloem of many plant species and cause hundreds of plant diseases worldwide. In nature, phytoplasmas are primarily transmitted by hemipteran vectors. While all phloem-feeding insects could in principle transmit phytoplasmas, only a limited number of species have been confirmed as vectors. Knowledge about factors that might determine the vector capacity is currently scarce. Here, we characterized the microbiomes of vector and non-vector species of apple proliferation (AP) phytoplasma ‘Candidatus Phytoplasma mali’ to investigate their potential role in the vector capacity of the host. We performed high-throughput 16S rRNA metabarcoding of the two principal AP-vectors Cacopsylla picta and Cacopsylla melanoneura and eight Cacopsylla species, which are not AP-vectors but co-occur in apple orchards. The microbiomes of all species are dominated by Carsonella, the primary endosymbiont of psyllids and a second uncharacterized Enterobacteriaceae endosymbiont. Each Cacopsylla species harboured a speciesspecific phylotype of both symbionts. Moreover, we investigated differences between the microbiomes of AP-vector versus non-vector species and identified the predominant endosymbionts but also Wolbachia and several minor taxa as potential indicator species. Our study highlights the importance of considering the microbiome in future investigations of potential factors influencing host vector competence. We investigated the potential role of symbiotic bacteria in the acquisition and transmission of phytoplasma. By comparing the two main psyillid vector species of Apple proliferation (AP) phytoplasma and eight co-occurring species, which are not able to vector AP-phytoplasma, we found differences in the microbial communities of AP-vector and non-vector species, which appear to be driven by the predominant symbionts in both vector species and Wolbachia and several minor taxa in the non-vector species. In contrast, infection with APphytoplasma did not affect microbiome composition in both vector species. Our study provides new insights into the endosymbiont diversity of Cacopsylla spp. and highlights the importance of considering the microbiome when investigating potential factors influencing host vector competenc

How do Plants-Having Different Exudation Patterns-Shape a Similar Microbial Community?

ABSTRACT Microorganisms associated with plants have been shown to improve plant growth and yield participating in the biogeochemical cycles of elements in soil. For these reasons, the rhizosphere microbiome is considered one of the key determinants of plant health and productivity. Plants can influence the qualitative and quantitative composition of the rhizosphere microbial community by releasing different classes of organic compound. Yet, this release depends on several factors, such as plant genotype, soil properties, plant nutritional status, climatic conditions. Within a previous study, we showed that the rhizosphere microbial communities associated to both iron (Fe)-sufficient and Fe-deficient tomato and barley plants, grown in different agricultural calcareous soils, were surprisingly similar and formed by bacterial strains that exhibit plant growthpromoting (PGPR) traits

A smart and sustainable future for viticulture is rooted in soil: How to face cu toxicity

In recent decades, agriculture has faced the fundamental challenge of needing to increase food production and quality in order to meet the requirements of a growing global population. Similarly, viticulture has also been undergoing change. Several countries are reducing their vineyard areas, and several others are increasing them. In addition, viticulture is moving towards higher altitudes and latitudes due to climate change. Furthermore, global warming is also exacerbating the incidence of fungal diseases in vineyards, forcing farmers to apply agrochemicals to preserve production yields and quality. The repeated application of copper (Cu)-based fungicides in con-ventional and organic farming has caused a stepwise accumulation of Cu in vineyard soils, posing environmental and toxicological threats. High Cu concentrations in soils can have multiple impacts on agricultural systems. In fact, it can (i) alter the chemical-physical properties of soils, thus com-promising their fertility; (ii) induce toxicity phenomena in plants, producing detrimental effects on growth and productivity; and (iii) affect the microbial biodiversity of soils, thereby influencing some microbial-driven soil processes. However, several indirect (e.g., management of rhizosphere processes through intercropping and/or fertilization strategies) and direct (e.g., exploitation of vine resistant genotypes) strategies have been proposed to restrain Cu accumulation in soils. Furthermore, the application of precision and smart viticulture paradigms and their related technologies could allow a timely, localized and balanced distribution of agrochemicals to achieve the required goals. The present review highlights the necessity of applying multidisciplinary approaches to meet the requisites of sustainability demanded of modern viticulture

Characterization of the bacterial community associated with larvae and adults of anoplophora chinensis collected in Italy by culture and culture-independent methods

The wood-boring beetle Anoplophora chinensis Forster, native to China, has recently spread to North America and Europe causing serious damage to ornamental and forest trees. The gut microbial community associated with these xylophagous beetles is of interest for potential biotechnological applications in lignocellulose degradation and development of pest-control measures. In this study the gut bacterial community of larvae and adults of A. chinensis, collected from different host trees in North Italy, was investigated by both culture and culture-independent methods. Larvae and adults harboured a moderately diverse bacterial community, dominated by Proteobacteria, Actinobacteria, and Firmicutes. The gammaproteobacterial family Enterobacteriaceae (genera Gibbsiella, Enterobacter, Raoultella, and Klebsiella) was the best represented. The abundance of such bacteria in the insect gut is likely due to the various metabolic abilities of Enterobacteriaceae, including fermentation of carbohydrates derived from lignocellulose degradation and contribution to nitrogen intake by nitrogen-fixing activity. In addition, bacteria previously shown to have some lignocellulose-degrading activity were detected at a relatively low level in the gut. These bacteria possibly act synergistically with endogenous and fungal enzymes in lignocellulose breakdown. The detection of actinobacterial symbionts could be explained by a possible role in the detoxification of secondary plant metabolites and/or protection against pathogens. \ua9 2013 Aurora Rizzi et al

Epiphytic Microbial Community and Post-Harvest Characteristics of Strawberry Fruits as Affected by Plant Nutritional Regime with Silicon

Despite being not essential to plants, Silicon (Si) has proven to have promoting effects on plants growth, yield, and resistance against biotic and abiotic stressors. The increase of concentration in specific minerals in plant tissues can also improve shelf-life, which, in fruits like strawberries, is also affected by the epiphytic microbial community. The present research was carried out to assess whether Si biofortification of strawberry plants, grown in soilless system, could affect plants yield and post-harvest feature of fruits during the storage period, carried out at three different temperatures (i.e., 1, 4 and 10 °C) for 7 and 14 days. Furthermore, we investigated whether the plant nutritional regime, specifically the Si fertilization, can impact the composition of microbial community. Our results showed that biofortification did not significantly affect fruits firmness, whereas, at the highest Si levels, an increase in titratable acidity was observed. The microbial community analysis highlighted for the first time the presence of probiotic bacteria, as Bacillus breve, which could present interesting technological features as strains adapted to the strawberry fruit-sphere. In addition, with the increasing levels of Si biofortification, the depletion of potentially pathogenic microorganisms, like Escherichia coli and Terrisporobacter glycolicus, was also observed. In conclusion, data here reported highlight for the first time the possible role played by the nutritional regimes of strawberry plants in shaping composition of the fruit epiphytic microbial community

Le savant et son époque à travers sa correspondance Seeger A. Bonebakker (1923-2005) et quelques notes sur Ḫalīl b. Aybak al-Ṣafadī (696-764/1297-1363)

This article proposes a survey of two great scholars’ in Arabic literature correspondences: a European of the 20th century, Seeger Adrianus Bonebakker, who is of special interest for us because he bequeathed all of his great library, personal notes and correspondence to Università Ca’ Foscari, and a subject of study of the former, Ḫalīl b. Aybak al-Ṣafadī, great littérateur and scholar of the first century of the Mamluk period. Letters sent and received are preserved in both cases and are primary sources on their network, but also on their personal life, personality and methodology