Molecular studies of microbial community structure on stained pages of Leonardo da Vinci's Atlantic Codex.

In 2006, after a visual inspection of the Leonardo da Vinci's Atlantic Codex by a scholar, active molds were reported to have been present on Codex pages showing areas of staining. In the present paper, molecular methods were used to assess the current microbiological risk to stained pages of the manuscript. Bacterial and fungal communities were sampled by a non-invasive technique employing nitrocellulose membranes. Denaturing gradient gel electrophoresis of 16 S rRNA gene and internal transcribed space regions were carried out to study the structure of the bacterial and fungal communities and band patterns were analyzed by the multivariate technique of principal component analysis. Any relationship between the presence of an active microbial community and staining was excluded. The presence of potential biodeteriogens was evaluated by constructing bacterial and fungal clone libraries, analyzing them by an operational taxonomic unit (OTU) approach. Among the bacteria, some OTUs were associated with species found on floors in clean room while others were identified with human skin contamination. Some fungal OTU representatives were potential biodeteriogens that, under proper thermo-hygrometric conditions, could grow. The retrieval of these potential biodeteriogens and microorganisms related to human skin suggests the need for a continuous and rigorous monitoring of the environmental conditions, and the need to improve handling procedures.

Micropollutants in Lake Como water in the context of circular economy: A snapshot of water cycle contamination in a changing pollution scenario.

In this work we evaluated the contamination of the water cycle in Como Bay by measuring 38 selected pharmaceuticals in two main wastewater treatment plant in Switzerland and in Italy, two influents (River Breggia and Cosia), lake water (epilimnion and hypolimnion), as well as potable water. The collection of comparative information on the presence and environmental fate of these substances contributes to set specific environmental quality standard (EQS). The results presented show that the contamination of the lake reflects national health policies, which deeply influence the usage of chemicals. The outcomes of this study give an overall picture of contamination in the area, showing that concentrations of the measured compounds are generally low and under the commonly adopted ecotoxicological and toxicological thresholds. Only in a few cases did the contamination appear to be noteworthy, for some of the most persistent compounds (antibiotic macrolides, diclofenac, irbesartan, carbamazepine and dihydrocarbamazepine, bezafibrate, furosemide and hydrochlorothiazide). Some concern can be also be raised for the presence of antibiotics (clarithromycin) in drinking water, although at very low levels, due to the problem of antibiotic resistance.

N-vanillylnonanamide tested as a non-toxic antifoulant, applied to surfaces in a polyurethane coating.

The potential on N-vanillylnonanamide (NVN) in preventing the attachment of Pseudomonas stutzeri and a Bacillus cereus-group strain was investigated. NVN up to 852 microM was not toxic, nor was it an energy source for either organism. Microbial attachment assays were carried out on glass and polylysine slides. with NVN being dispersed in or applied to the surfaces using a polyurethane coating. NVN at 205 microM inhibited Bacillus adhesion on glass slides by 48% and the percentage did not significantly increase at 852 microM. NVN blended into or sprayed onto the coating at 205 micromol/kg did not prevent adhesion. The compound is therefore not useful as an antifouling product under the tested coating conditions.

Effect of Powdered Activated Carbon as Advanced Step in Wastewater Treatments on Antibiotic Resistant Microorganisms.

BACKGROUND: Conventional wastewater treatment plants discharge significant amounts of antibiotic resistant bacteria and antibiotic resistance genes into natural water bodies contributing to the spread of antibiotic resistance. Some advanced wastewater treatment technologies have been shown to effectively decrease the number of bacteria. Nevertheless, there is still a lack of knowledge about the effectiveness of these treatments on antibiotic resistant bacteria and antibiotic resistant genes. To the best of our knowledge, no specific studies have considered how powdered activated carbon (PAC) treatments can act on antibiotic resistant bacteria, although it is essential to assess the impact of this wastewater treatment on the spread of antibiotic resistant bacteria. METHODS: To address this gap, we evaluated the fate and the distribution of fluorescent-tagged antibiotic/ antimycotic resistant microorganisms in a laboratory-scale model simulating a process configuration involving powdered activated carbon as advanced wastewater treatment. Furthermore, we studied the possible increase of naturally existing antibiotic resistant bacteria during the treatment implementing PAC recycling. RESULTS: The analysis of fluorescent-tagged microorganisms demonstrated the efficacy of the PAC adsorption treatment in reducing the load of both susceptible and resistant fluorescent microorganisms in the treated water, reaching a removal efficiency of 99.70%. Moreover, PAC recycling did not increase the resistance characteristics of cultivable bacteria neither in the sludge nor in the treated effluent. CONCLUSION: Results suggest that wastewater PAC treatment is a promising technology not only for the removal of micropollutants but also for its effect in decreasing antibiotic resistant bacteria release.

Bacterial and fungal deterioration of the Milan Cathedral marble treated with protective synthetic resins.

Surfaces are continuously exposed to physical, chemical and biological degradation. Among the biological agents that cause deterioration, microorganisms are of critical importance. This work is part of a research programme for the characterisation of the alterations of the Milan Cathedral (Italy). Four stone samples of the Milan Cathedral were chemically analysed and the microbiological growth assessed. X-ray diffraction (XRD) showed that calcite was always present in each sample and one sample was also characterised by the chemical form of alteration gypsum. Using Fourier Transform Infrared Spectroscopy (FTIR) together with Scanning Electron Microscopy (SEM), it was possible to prove that the samples were consolidated with the synthetic acrylics and epoxy resins. The green-black biological patinas of the specimens were studied using cultivation, microscope observations and a method for single-cell detection. Sampling for fluorescent in-situ hybridisation (FISH), with ribosomal RNA targeted oligonucleotide probes, was also performed using adhesive tapes. The bulk of the prokaryotes were Bacteria but some Archaea were also found. The bacterial cells were further characterised using specific probes for Cyanobacteria, and alpha-, beta-and gamma-Proteobacteria. In addition, black fungi isolated from the stone and the fungi of the standard ASTM G21-96(2002) method were employed to test if the detected synthetic resins could be used as the sole source of carbon and energy. One isolated Cladosporium sp. attacked the freshly dried acrylic resin. Results show that the detected bacteria and fungi can cause severe damage both to the stone monument and its synthetic consolidants.

Biodeterioration of modern materials in contemporary collections: can biotechnology help?

Contemporary collections frequently contain man-made materials. Although synthetic materials are considered more resistant to chemical, physical and biological damage than natural materials, they can also undergo rapid deterioration. In this Opinion article, we claim that biotechnology can help to identify biodeteriogens and prevent colonisation of polymeric surfaces through the application of biological products that reduce cell adhesion. We report the study of 'Futuro', made in 1965 by the Finnish architect Matti Suuronne. This ski-cabin, constructed of glassfibre-reinforced polyester, polyester-polyurethane, and poly(methylmethacrylate), was significantly degraded by conspicuous growth of microorganisms, identified as Cyanobacteria and Archaea using fluorescent in situ hybridisation. Ultimately, if biodeteriogens are able to adhere to the polymer surfaces, molecules with enzymatic activity can help to prevent the formation of biofilms--a main cause of deterioration--and aid the work of the conservator.

A simple and reliable methodology to detect egg white in art samples.

A protocol for a simple and reliable dot-blot immunoassay was developed and optimized to test work of art samples for the presence of specific proteinaceus material (i.e. ovalbumin-based). The analytical protocol has been extensively set up with respect, among the other, to protein extraction conditions, to densitometric analysis and to the colorimetric reaction conditions. Feasibility evaluation demonstrated that a commercial scanner and a free image analysis software can be used for the data acquisition and elaboration, thus facilitating the application of the proposed protocol to commonly equipped laboratories and to laboratories of museums and conservation centres. The introduction of method of standard additions in the analysis of fresh and artificially aged laboratory-prepared samples, containing egg white and various pigments, allowed us to evaluate the matrix effect and the effect of sample aging and to generate threshold density values useful for the detection of ovalbumin in samples from ancient works of art. The efficacy of the developed dot-blot immunoassay was proved testing microsamples from 13th-16th century mural paintings of Saint Francesco Church in Lodi (Italy). Despite the aging, the altered conditions of conservation, the complex matrix, and the micro-size of samples, the presence of ovalbumin was detected in all those mural painting samples where mass-spectrometry-based proteomic analysis unambiguously detected ovalbumin peptides.

The effect of copper on the structure of the ammonia-oxidizing microbial community in an activated sludge wastewater treatment plant.

Molecular approaches based on both whole-cell and extracted DNA were applied to assess chronic and acute effects of copper on the ammonia oxidizing bacteria (AOB) community in an activated sludge system. The ammonia monooxygenase amoA gene was chosen as the functional marker to evaluate changes in the AOB community. Using in situ polymerase chain reaction, we were able to visualize the peripheric distribution of the amoA gene-possessing bacteria in activated sludge flocs. The AOB biomass content was constant in both chronic and acute toxicity experiments, but the ammonia oxidizing activity, measured as ammonia uptake rate, was different. The AOB community structural changes due to the copper presence were evaluated by multivariate analysis of the DGGE bands profiles. The chronic contamination caused a change in the AOB community compared to the control. In contrast, acute inputs led to a temporary change in the AOB community, after which the community was similar to the control. Recovery after acute intoxication was achieved after 72 h. The present study reports on the effects of chronic and acute copper contamination on the ammonia uptake ability of the AO microorganisms and the structure of the AOB community in a wastewater system and, as a consequence, gives indications on the response of wastewater plants under similar conditions.

Synthetic consolidants attacked by melanin-producing fungi: case study of the biodeterioration of Milan (Italy) cathedral marble treated with acrylics.

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.

Microbiological aspects of humid husk composting.

The feasibility of composting as disposal practice of husk mixed with olive mill wastewaters (OMW) was studied in the present research. The process was investigated with regards to some reliable and easy to be determined microbial activity parameters such as the ATP content, the activity of a pool of enzymes and the viable counts, keeping in mind the well known bias of this last technique. Two different composting technologies were compared: static pile and reactor by studying the cured composts obtained. Among the bioindicators tested, the composting process trend was described better by the ATP content and the activity of some enzymes. In fact, the ATP content showed an increase during the thermophilic phase in both the pile and the reactor, and decreased at the end of the process, it was also higher in the bioreactor-pile technology than in the pile. With regard to the enzymatic activity, with the reactor technology experiment, two peaks were evidenced in the thermophilic phase and during the curing phase in pile, and a drop during the transfer of material from the reactor to the pile. The quality of the cured product obtained using the reactor technology has been evaluated considering phytoxicity and hygienic features: the stabilised compost resulted to have neither phytoxical effect, nor faecal indicator contaminants.