287 research outputs found
Discovery of a second locality for the narrow endemic Anthemis ismelia (Asteraceae) in NW Sicily
A new population of Anthemis ismelia (Asteraceae) has been discovered on Mt Pecoraro (Cinisi, NW Sicily), a limestone headland at about 14 km from Mt Gallo (Palermo), the locus classicus et unicus of this species described in 1884. Taxonomic framework, distribution update, habitat characterisation, ecology and phytosociological framework are provided, as well as meta-population numerical estimates and risk status assessment
Fragments of -thymosin from the sea urchin Paracentrotus lividus as potential antimicrobial peptides against staphylococcal biofilms
The immune mediators in echinoderms can be a potential source of novel antimicrobial peptides (AMPs) applied
toward controlling pathogenic staphylococcal biofilms that are intrinsically resistant to conventional antibiotics.
The peptide fraction <5 kDa from the cytosol of coelomocytes of the sea urchin Paracentrotus lividus (5-CC)
was tested against a group of Gram-positive and Gram-negative pathogen reference strains. The 5-CC of P. lividus
was active against all planktonic-tested strains but also showed antibiofilm properties against staphylococcal strains.
Additionally,wedemonstrated the presenceof three smallpeptides in the5-CCbelonging tosegment 9-41of aP. lividus
-thymosin. The smallest of these peptides in particular, showed the common chemical\u2013physical characteristics of
AMPs. This novel AMP from -thymosin has high potential activity as an antibiofilm agent, acting on slow-growing
bacterial cells that exhibit a reduced susceptibility to conventional antibiotics and represent a reservoir for recurrent
biofilm-associated infections
Understanding COVID-19 Epidemics: A Multi-Scale Modeling Approach
COVID-19 was declared a pandemic by the World Health Organization in March 2020 and, since then, research on mathematical modeling became imperative and very influential to understand the epidemiological dynamics of disease spreading and control under different scenarios. In this chapter, two different approaches to model the spread of COVID-19 are presented. The model frameworks are described and results are presented in connection with the current epidemiological situation of vaccination roll-out. This chapter is structured as follows. Section 2 presents the stochastic SHARUCD modeling framework developed within a modeling task force created to support public health managers during the COVID-19 crisis. As an extension of the basic SHAR (Susceptible-Hospitalized-Asymptomatic-Recovered) model, the SHARUCD models were parameterized and validated with empirical data for the Basque Country, Spain, and have been used (up until now) to monitor COVID-19 spreading and control over the course of the pandemic. Section 3 introduces the kinetic theory of active particles (KTAP) model for the spread of a disease. With an exploratory analysis, we present a possible way to deal with heterogeneity and multiscale features. Section 4 concludes this work, with a discussion on both models and further research perspectives description
BIOFILM GENES PRESENCE, BIOFILM ANALYSIS AND ANTIMICROBIAL PEPTIDES ACTIVITY AGAINST STAPHYLOCOCCUS AUREUS OF ANIMAL ORIGIN
Critical fluctuations in epidemic models explain COVIDâ19 postâlockdown dynamics
As the COVID-19 pandemic progressed, research on mathematical modeling became imperative and
very influential to understand the epidemiological dynamics of disease spreading. The momentary
reproduction ratio r(t) of an epidemic is used as a public health guiding tool to evaluate the course of
the epidemic, with the evolution of r(t) being the reasoning behind tightening and relaxing control
measures over time. Here we investigate critical fluctuations around the epidemiological threshold,
resembling new waves, even when the community disease transmission rate ÎČ is not signifcantly
changing. Without loss of generality, we use simple models that can be treated analytically and
results are applied to more complex models describing COVID-19 epidemics. Our analysis shows that,
rather than the supercritical regime (infectivity larger than a critical value, ÎČ>ÎČc) leading to new
exponential growth of infection, the subcritical regime (infectivity smaller than a critical value, ÎČ<ÎČc)
with small import is able to explain the dynamic behaviour of COVID-19 spreading after a lockdown
lifting, with r(t) â 1 hovering around its threshold value.BMTF âMathematical Modeling Applied to Healthâ Project
European Unionâs Horizon 2020 research and innovation programme under the Marie SkĆodowska-Curie grant
agreement No 79249
Potential uses of olive oil secoiridoids for the prevention and treatment of cancer: A narrative review of preclinical studies
The Mediterranean diet (MD) is a combination of foods mainly rich in antioxidants and anti-inflammatory nutrients that have been shown to have many health-enhancing effects. Extra-virgin olive oil (EVOO) is an important component of the MD. The importance of EVOO can be attributed to phenolic compounds, represented by phenolic alcohols, hydroxytyrosol, and tyrosol, and to secoiridoids, which include oleocanthal, oleacein, oleuropein, and ligstroside (along with the aglycone and glycosidic derivatives of the latter two). Each secoiridoid has been studied and char-acterized, and their effects on human health have been documented by several studies. Secoiridoids have antioxidant, anti-inflammatory, and anti-proliferative properties and, therefore, exhibit anti-cancer activity. This review summarizes the most recent findings regarding the pharmacological properties, molecular targets, and action mechanisms of secoiridoids, focusing attention on their preventive and anti-cancer activities. It provides a critical analysis of preclinical, in vitro and in vivo, studies of these natural bioactive compounds used as agents against various human cancers. The prospects for their possible use in human cancer prevention and treatment is also discussed
A synthetic derivative of antimicrobial peptide holothuroidin 2 from mediterranean sea cucumber (Holothuria tubulosa) in the control of Listeria monocytogenes
Due to the limited number of available antibiotics, antimicrobial peptides (AMPs) are considered antimicrobial candidates to fight difficult-to-treat infections such as those associated with biofilms. Marine environments are precious sources of AMPs, as shown by the recent discovery of antibiofilm properties of Holothuroidin 2 (H2), an AMP produced by the Mediterranean sea cucumber Holothuria tubulosa. In this study, we considered the properties of a new H2 derivative, named H2d, and we tested it against seven strains of the dangerous foodborne pathogen Listeria monocytogenes. This peptide was more active than H2 in inhibiting the growth of planktonic L. monocytogenes and was able to interfere with biofilm formation at sub-minimum inhibitory concentrations (MICs). Atomic-level molecular dynamics (MD) simulations revealed insights related to the enhanced inhibitory activity of H2d, showing that the peptide is characterized by a more defined tertiary structure with respect to its ancestor. This allows the peptide to better exhibit an amphipathic character, which is an essential requirement for the interaction with cell membranes, similarly to other AMPs. Altogether, these results support the potential use of our synthetic peptide, H2d, as a template for the development of novel AMP-based drugs able to fight foodborne that are resistant to conventional antibiotics
Seasonally Forced SIR Systems Applied to Respiratory Infectious Diseases, Bifurcations, and Chaos
We investigate models to describe respiratory diseases with fast mutating virus pathogens such that after some years the aquired resistance is lost and hosts can be infected with new variants of the pathogen. Such models were initially suggested for respiartory diseases like influenza, showing complex dynamics in reasonable parameter regions when comparing to historic empirical influenza like illness data, e.g., from Ille de France. The seasonal forcing typical for respiratory diseases gives rise to the different rich dynamical scenarios with even small parameter changes. Especially the seasonality of the infection leads for small values already to period doubling bifurcations into chaos, besides additional coexisting attractors. Such models could in the future also play a role in understanding the presently experienced COVID-19 pandemic, under emerging new variants and with only limited vaccine efficacies against newly upcoming variants. From first period doubling bifurcations, we can eventually infer at which close by parameter regions complex dynamics including deterministic chaos can arise.Marie SkĆodowska-Curie grant agreement No. 79249
Importance of meteorological variables for aeroplankton dispersal in an urban environment
Passive wind dispersal is one of the major mechanisms through which organisms disperse and colonize new areas. The detailed comprehension of which factors affect this process may help to preserve its efficiency for years to come. This is especially important in the current context of climate change, which may seriously alter weather regimes that drive dispersal, and is crucial in urban contexts, where biodiversity is dramatically threatened by pollution and fragmentation of natural patches. Despite its interest, the analysis of factors affecting aeroplankton dispersal in urban environments is rare in literature. We sampled aeroplankton community uninterruptedly every 4 hours from 17th May to 19th September 2011 in the urban garden of Parco d'Orléans, within the campus of the University of Palermo (Sicily). Sampling was performed using a Johnson-Taylor suction trap with automatized sample storing. Weather variables were recorded at a local meteorological station. Overall, 11,739 insects were caught during the present study, about 60% of these belonged to the order Hymenoptera, with particular presence of families Agaonidae and Formicidae. The suction trap also captured specimens of very small size, and in some cases, species caught were new records for Italy. Composition and abundance of aeroplankton community was influenced by alternation day/night, as well as by daily fluctuations of climatic variables, for example fluctuating temperature . The diversity of samples was also studied and resulted higher when wind blew from the nearby green area. Our findings confirm that passive transport of arthropods strictly depends on weather conditions, and that the presence of natural areas within the urban environment significantly contribute to raise aeroplankton diversity, eventually fuelling overall biodiversity at a local scale. We discuss how climate change may affect future dispersal of these organisms
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