A role for microbial selection in frescoes' deterioration in Tomba degli Scudi in Tarquinia, Italy

Mural paintings in the hypogeal environment of the Tomba degli Scudi in Tarquinia, Italy, show a quite dramatic condition: the plaster mortar lost his cohesion and a white layer coating is spread over almost all the wall surfaces. The aim of this research is to verify if the activity of microorganisms could be one of the main causes of deterioration and if the adopted countermeasures (conventional biocide treatments) are sufficient to stop it. A biocide treatment of the whole environment has been carried out before the conservative intervention and the tomb has been closed for one month. When the tomb was opened again, we sampled the microorganisms present on the frescoes and we identified four Bacillus species and one mould survived to the biocide treatment. These organisms are able to produce spores, a highly resistant biological form, which has permitted the survival despite the biocide treatment. We show that these Bacillus strains are able to produce calcium carbonate and could be responsible for the white deposition that was damaging and covering the entire surface of the frescoes. Our results confirm that the sanitation intervention is non always resolutive and could even be deleterious in selecting harmful microbial communities

Annurca apple (M. pumila Miller cv Annurca) extracts act against stress and ageing in S. cerevisiae yeast cells

During the past years, a number of studies have demonstrated the positive effect of apple on ageing and different diseases such as cancer, degenerative and cardiovascular diseases. The unicellular yeast Saccharomyces cerevisiae represents a simple eukaryotic model to study the effects of different compounds on lifespan. We previously demonstrated that apple extracts have anti-ageing effects in this organism because of their antioxidant properties. In particular, the effect is related to the presence in this fruit of polyphenols, which give a large contribution to the antioxidant activity of apples

New perspectives from South-Y-East, not all about death. A report of the 12lnternational Meeting on Yeast Apoptosis in Bari, Italy, May 14th-18th, 2017

Over the last 14 years, the field of yeast regulated cell death (RCD) has been expanding to more and more biomedical research themes, including aging, human diseases, cell stress response, metabolism and systems biology. The 12th International Meeting on Yeast Apoptosis (IMYA12), which was held in Bari, Italy from May 14th to 18th, 2017, nicely reflected this trend. This year, more than 100 participants, among which senior and young scientists from Europe, USA, North Africa and Japan, had an intense and open exchange of achievements and ideas. This open and informal communication among researchers has been a constant hallmark of all the IMYA meetings. The global yeast death community was embraced and inspired by the lively and warm atmosphere of Bari, the capital city of Apulia, and its beautiful surroundings, with colorful landscapes, historical and artistic heritage, tastes and scents that reflect the interface between Eastern and Western culture

Increased levels of RNA oxidation enhance the reversion frequency in aging pro-apoptotic yeast mutants

Despite recent advances in understanding the complexity of RNA processes, regulation of the metabolism of oxidized cellular RNAs and the mechanisms through which oxidized ribonucleotides affect mRNA translation, and consequently cell viability, are not well characterized. We show here that the level of oxidized RNAs is markedly increased in a yeast decapping Kllsm4Δ1 mutant, which accumulates mRNAs, ages much faster that the wild type strain and undergoes regulated-cell-death. We also found that in Kllsm4Δ1 cells the mutation rate increases during chronological life span indicating that the capacity to han- dle oxidized RNAs in yeast declines with aging. Lowering intracellular ROS levels by antioxidants recovers the wild- type phenotype of mutant cells, including reduced amount of oxidized RNAs and lower mutation rate. Since mRNA oxidation was reported to occur in different neurodegen- erative diseases, decapping-deficient cells may represent a useful tool for deciphering molecular mechanisms of cell response to such conditions, providing new insights into RNA modification-based pathogenesis

mRNA degradation and its effect on cellular lifespan and apoptosis in yeast

The control of mRNA degradation is an important element in regulation of gene expression. In all eukaryotes, the decay of mRNAs usually starts with the removal of the 3′ end poly(A) tail. In the principal degradation pathway in the yeast S. cerevisiae, deadenylation is followed by decapping and by 5′ to 3′ mRNA degradation by the exonuclease Xrn1. We previously reported that yeast mutants in genes of the mRNA decapping pathway show premature aging and undergo programmed cell death. These traits are accompanied by elevated histone mRNA levels persisting throughout the cell cycle and defects in S-phase progression. Analyzing the data concerning the negative genetic interactions of specific genes, as well those obtained with genome wide analysis, we found that gene mutants that are lethal/sick with lsm genes can be clustered in functional groups such as histone/chromatine modifications, protein translation, DNA replication/repair, nuclear mRNA export, mitochondrial function/biogenesis and autophagy. We are currently studying the role of these pathways in cellular aging and apoptosis related to mRNA turn over

NEM1 acts as a suppressor of apoptotic phenotypes in LSM4 yeast mutants

Saccharomyces cerevisiae mutants in the essential gene LSM4, involved in messenger RNA decapping, and expressing a truncated form of the LSM4 gene of the yeast Kluyveromyces lactis (Kllsm4Δ1), show premature aging accompanied by the presence of typical markers of apoptosis and high sensitivity to oxidative stressing agents. We isolated multicopy extragenic suppressors of these defects, transforming the Kllsm4Δ1 mutant with a yeast DNA library and selecting clones showing resistance to acetic acid. Here we present one of these clones, carrying a DNA fragment containing the NEM1 gene (Nuclear Envelope Morphology protein 1), which encodes the catalytic subunit of the Nem1p-Spo7p phosphatase holoenzyme. Nem1p regulates nuclear growth by controlling phospholipid biosynthesis and it is required for normal nuclear envelope morphology and sporulation. The data presented here correlate the mRNA metabolism with the biosynthesis of phospholipids and with the functionality of the endoplasmic reticulum

Poloxamer 338 Affects Cell Adhesion and Biofilm Formation in Escherichia coli: Potential Applications in the Management of Catheter-Associated Urinary Tract Infections

Poloxamers are nontoxic, amphiphilic copolymers used in different formulations. Due to its surfactant properties, Poloxamer 338 (P388) is herein proposed as a strategy to avoid biofilm formation often causing recalcitrant catheter-associated urinary tract infections (CAUTI). The aim is to evaluate the ability of P388 coatings to affect the adhesion of Ec5FSL and Ec9FSL Escherichia coli strains on silicone urinary catheters. Attenuated total reflection infrared spectroscopy, atomic force microscopy, and static water contact angle measurement were employed to characterize the P388-coated silicone catheter in terms of amount of P388 layered, coating thickness, homogeneity, and hydrophilicity. In static conditions, the antifouling power of P388 was defined by comparing the E. coli cells adherent on a hydrophilic P388-adsorbed catheter segment with those on an uncoated one. A P388-coated catheter, having a homogeneous coverage of 35 nm in thickness, reduced of 0.83 log10 and 0.51 log10 the biofilm of Ec5FSL and Ec9FSL, respectively. In dynamic conditions, the percentage of cell adhesion on P388-adsorbed silicone channels was investigated by a microfluidic system, simulating the in vivo conditions of catheterized patients. As a result, both E. coli isolates were undetected. The strong and stable antifouling property against E. coli biofilm lead us to consider P388 as a promising anti-biofilm agent for CAUTIs control

Functional Screening of Antibiotic Resistance Genes from a Representative Metagenomic Library of Food Fermenting Microbiota

Lactic acid bacteria (LAB) represent the predominant microbiota in fermented foods. Foodborne LAB have received increasing attention as potential reservoir of antibiotic resistance (AR) determinants, which may be horizontally transferred to opportunistic pathogens. We have previously reported isolation of AR LAB from the raw ingredients of a fermented cheese, while AR genes could be detected in the final, marketed product only by PCR amplification, thus pointing at the need for more sensitive microbial isolation techniques. We turned therefore to construction of a metagenomic library containing microbial DNA extracted directly from the food matrix. To maximize yield and purity and to ensure that genomic complexity of the library was representative of the original bacterial population, we defined a suitable protocol for total DNA extraction from cheese which can also be applied to other lipid-rich foods. Functional library screening on different antibiotics allowed recovery of ampicillin and kanamycin resistant clones originating from Streptococcus salivarius subsp. thermophilus and Lactobacillus helveticus genomes. We report molecular characterization of the cloned inserts, which were fully sequenced and shown to confer AR phenotype to recipient bacteria. We also show that metagenomics can be applied to food microbiota to identify underrepresented species carrying specific genes of interest