A fractional model for the COVID-19 pandemic: Application to Italian data

We provide a probabilistic SIRD model for the COVID-19 pandemic in Italy, where we allow the infection, recovery and death rates to be random. In particular, the underlying random factor is driven by a fractional Brownian motion. Our model is simple and needs only some few parameters to be calibrated.Comment: 20 pages, 26 figure

Carvacrol selective pressure allows the occurrence of genetic resistant variants of Listeria monocytogenes EGD-e

Essential oils and their constituents, such as carvacrol, are potential food preservatives because of their great antimicrobial properties. However, the long-term effects of these compounds are unknown and raise the question of whether resistance to these antimicrobials could emerge. This work aims to evaluate the occurrence of genetic resistant variants (RVs) in Listeria monocytogenes EGD-e by exposure to carvacrol. Two protocols were performed for the RVs selection: (a) by continuous exposure to sublethal doses, where LmSCar was isolated, and (b) by reiterative exposure to short lethal treatments of carvacrol, where LmLCar was isolated. Both RVs showed an increase in carvacrol resistance. Moreover, LmLCar revealed an increased cross-resistance to heat treatments at acid conditions and to ampicillin. Whole-genome sequencing identified two single nucleotide variations in LmSCar and three non-silent mutations in LmLCar. Among them, those located in the genes encoding the transcriptional regulators RsbT (in LmSCar) and ManR (in LmLCar) could contribute to their increased carvacrol resistance. These results provide information regarding the mode of action of this antimicrobial and support the importance of knowing how RVs appear. Further studies are required to determine the emergence of RVs in food matrices and their impact on food safety

FUSULINOIDEANS FROM THE PUENTELLÉS FORMATION (UPPER CARBONIFEROUS, NW SPAIN): DISCUSSION ON PHYLOGENY, PALEOECOLOGY AND PALEOBIOGEOGRAPHY

The Cantabrian Zone is the only area in Western Europe that contains marine successions of Kasimovian and Gzhelian (late Late Carboniferous, late Pennsylvanian) age. These successions yield fusulinoideans that are presently the subject of an in depth-study by members of a IUGS SCCS working group intending to find stratigraphic markers for the subdivision of the Carboniferous System. The youngest fusulinoidean faunas of the Cantabrian Zone are recorded in the Puentellés Formation, a succession of calcareous strata consisting of two members. The lower member is made up of reworked and re-sedimented carbonates, which form shallow turbidite deposits showing frequent lateral changes of facies, whereas the upper member corresponds to autochthonous limestones, mainly consisting of dark mudstones, skeletal wackestones and thick-bedded boundstones. Generally speaking, the lower member is late Kasimovian in age while the upper one is early Gzhelian. However, there are also a few successions of late Kasimovian age that show sedimentary facies similar to those of the upper member. The fusulinoidean assemblages from the lower member are dominated by elongated species of the genus Ferganites, which sometimes occur with Schubertella and Staffella species. Rauserites, Tumefactus, Jigulites, Quasifusulina, as well as certain Ferganites species showing obese shell, mainly appear in strata belonging to the upper member.Detailed analyses of the fusulinoideans from the Cantabrian Zone have allowed several questions related to their paleoecology, biostratigraphy, and paleobiogeography to be ascertained. First, it has been shown that the Ferganites accumulated in the strata of the lower member could have lived in near-shore and high-energy environments. The presence of some relevant forms (e. g. Rauserites cf. rossicus, and Jigulites sp.) allow a correlation between the Cantabrian successions and the standard stratigraphic units of the Russian Platform. Moreover, the composition of the fusulinoidean assemblages clearly shows the biogeographic affinities of the Cantabrian Zone with the Carnic Alps and the Central Asian regions. On the contrary, these assemblages differ greatly from those in other western Eurasian areas, such as the Russian Platform and the Donets Basin, suggesting that these areas were not well-connected with the Paleo-Tethys.   Some observations give rise to relevant questions on more general aspects dealing with the latest Carboniferous fusulinoideans while yielding, at the same time, preliminary data for solving them. This is the case of the phrenotheca, an inner partition existing in some fusulinoidean shells whose functional role is still uncertain. The abundance in the Cantabrian Zone strata of Tumefactus specimens showing phrenotheca provides information for reconstructing its geometry as well as enabling speculation on its likely function. Another problematic aspect concerns the origin and distribution of the genus Triticites. It is noteworthy that this genus seems to be absent from both the Cantabrian Zone and most Eurasian areas, bringing up the question of whether the American and the Eurasian Triticites really had a common ancestor. The possibilities involved are discussed here.&nbsp

Emerging mutant populations of Listeria monocytogenes EGD-e under selective pressure of Thymbra capitata essential oil question its use in food preservation

Due to their excellent antimicrobial properties, essential oils (EO) have been proposed as potential preservatives for certain kinds of foods, such as dairy products. However, the occurrence of pathogenic populations that are resistant to EOs could pose a health risk. This report seeks to assess the emergence of resistant populations in Listeria monocytogenes EGD-e growth at 37 °C under selective pressure of Thymbra capitata EO (TCO), to characterise their resistance in laboratory media, and to identify their genotypic changes, as well as to evaluate the resistance in skimmed milk. TCO cyclic treatment allowed the isolation of two L. monocytogenes EGD-e resistant strains against the EO: LmSTCO by sublethal doses (75 µL/L TCO) and LmLTCO by lethal doses (300 µL/L TCO) after 20 and 30 cycles, respectively. Both strains displayed an increase of the minimum inhibitory and bactericidal concentration against TCO and a higher survival rate after lethal treatments than the wild-type strain (LmWT). Growth kinetics revealed a better adaptation of LmSTCO in presence of TCO, while LmLTCO grew more slowly compared to LmWT, even in the absence of the antimicrobial. Moreover, a slight increase in cross-resistance to antibiotics was observed: LmSTCO to β-lactams and LmLTCO to a series of broad-spectrum antibiotics. The genomic study revealed one sole nucleotide change in LmSTCO located in plsC gene codifying an enzyme involved in the production of phosphatidic acid, a precursor in cell membrane synthesis. Five genetic variations were found in LmLTCO: among them, the deletion of an ATP-synthesis system involved in slowing bacterial growth. Inhibition and inactivation assays in skimmed milk confirmed the increased resistance of both strains, thereby indicating a safety risk in case these strains emerge in the food chain. These results strongly suggest that the occurrence of such resistances should be taken into account in order to ensure the efficacy of natural antimicrobials in the design of food preservation strategies

Salmonella enterica serovar Typhimurium genetic variants isolated after lethal treatment with Thymbra capitata essential oil (TCO) showed increased resistance to TCO in milk

The high prevalence of Salmonella enterica in milk poses a risk of considerable concern in the preservation of certain dairy products, mainly those elaborated from raw milk. Essential oils (EOs) have been proposed as a promising food preservative for such products due to their strong antimicrobial properties. Additionally, these natural antimicrobials have been shown to be effective against multi-drug resistant strains. They can thus also be utilized to prevent the dissemination of antimicrobial resistances (AMR). However, recent evidence of the development of bacterial resistance under EO treatments may call their use into question. This study sought to assess the emergence of antimicrobial resistant genetic variants of S. enterica serovar Typhimurium from survivors after cyclic exposure to lethal doses (>5 log10 cycles of inactivation) of Thymbra capitata EO (TCO), in order to evaluate the impact that it could have on milk preservation, to ascertain whether cross-resistance to antibiotics occurs, and to identify the genomic changes responsible for their phenotype. Isolated strains by TCO (SeTCO) showed a two-fold increase in minimum inhibitory and bactericide concentrations (MIC and MBC) of TCO compared to Salmonella enterica serovar Typhimurium wild-type strain (SeWT) in laboratory growth medium, as well as a greater adaptation and growth rate in the presence of the EOs and a higher survival to TCO treatments in buffers of pH 4.0 and 7.0. The increased resistance of SeTCO was confirmed in skimmed milk: 300 μL/L TCO reduced only 1 log10 cycle of SeTCO population, whereas it inactivated more than 5 log10 cycles in SeWT. Moreover, SeTCO showed an increased cross-resistance against aminoglycosides, quinolones and tetracyclines. Whole genome sequencing revealed 5 mutations in SeTCO: 2 in genes involved in O-antigens synthesis (rfbV and rfbX), 2 in genes related to adaptation to the growing medium (trkA and glpK), and 1 in a redox-sensitive transcriptional regulator (soxR). The phenotypic characterization of a constructed SeWT strain with mutant soxRSeTCO demonstrated that the mutation of soxR was the main cause of the increased resistance and tolerance observed in SeTCO against TCO and antibiotics. The emergence of resistant strains against EOs might jeopardize their use as food preservatives. Further studies will thus be required to determine under which conditions such resistant strains might occur, and to assess the food risk they may pose, as well as to ascertain their impact on the spread of AMR

Discontinuation of low dose aspirin and risk of myocardial infarction: case-control study in UK primary care

Objectives To evaluate the risk of myocardial infarction and death from coronary heart disease after discontinuation of low dose aspirin in primary care patients with a history of cardiovascular events

Hemoparasites and immunological parameters in Snow Bunting (Plectrophenax nivalis) nestlings

Knowledge on hemoparasites and immunological parameters in wild birds with Arctic distribution is limited. In this study, we chose the Snow Bunting (Plectrophenax nivalis) as model species to address this issue. Using nestlings, we aimed at (i) detecting hemoparasites with vector-borne transmission (via microscopic and molecular methods) and nest-dwelling ectoparasites and at (ii) exploring the relationship between several immunological parameters and parasitism. Nestlings were infected by Lankesterella parasites but hemoparasites of the genera Plasmodium, Haemoproteus, Leucocytozoon, Trypanosoma, Hepatozoon or Babesia were not found. This result may indicate the lack of suitable dipteran vectors or the inability of haemosporidians to reproduce in the Arctic region. Inflammation in response to the phytohaemagglutinin (PHA) injection was negatively related to infection by Lankesterella and positively related to weight gain in nestlings. The number of leukocytes and IgG level were not related to infection or PHA response, although the relationship between IgG level and PHA immune response was marginally significant. Besides, nestlings reared in mite-infected nests showed higher IgG level than those reared in mite-free nests. Taken together, (i) the positive relationship between PHA response/weight gain and PHA response/IgG level could reflect the nestlings? nutritional status; and (ii) the higher IgG level in nestlings reared in mite-infected nests may be the result of a specific immune response to mite antigens. Different parasites may alter distinct immunological parameters in birds breeding under extreme weather conditions.Ministerio de Ciencia e Innovació

Phenotypic and genotypic comparison of antimicrobial-resistant variants of Escherichia coli and Salmonella Typhimurium isolated from evolution assays with antibiotics or commercial products based on essential oils

On account of the widespread development and propagation of antimicrobial-resistant (AMR) bacteria, essential oils (EOs) have emerged as potential alternatives to antibiotics. However, as already observed for antibiotics, recent studies have raised concerns regarding the potential emergence of resistant variants (RVs) to EOs. In this study, we assessed the emergence of RVs in Escherichia coli and Salmonella enterica Typhimurium after evolution assays under extended exposure to subinhibitory doses of two commercial EOs (AEN and COLIFIT) as well as to two antibiotics (amoxicillin and colistin). Phenotypic characterization of RVs from evolution assays with commercial EOs yielded no relevant increases in the minimum inhibitory concentration (MIC) of E. coli and did not even modify MIC values in S. Typhimurium. Conversely, RVs of E. coli and S. Typhimurium isolated from evolution assays with antibiotics showed increased resistance. Genotypic analysis demonstrated that resistance to commercial EOs was associated with enhanced protection against oxidative stress and redirection of cell energy toward efflux activity, while resistance to antibiotics was primarily linked to modifications in the cell binding sites of antibiotics. These findings suggest that AEN and COLIFIT could serve as safe alternatives to antibiotics in combating the emergence and dissemination of antimicrobial resistance within the agrifood system

On the heritability of blue-green eggshell coloration

Avian blue-green eggshell coloration has been proposed as a female signal of genetic or phenotypic quality to males. However, little is known about the relative importance of additive genetic and environmental effects as sources of eggshell colour variation in natural populations. Using 5 years of data and animal models, we explored these effects in a free-living population of pied flycatchers. Permanent environmental and year effects were negligible, although year environmental variance (VYear) was significant for all but one of the traits. However, we found high–moderate narrow-sense heritabilities for some colour parameters. Within-clutch colour variability showed the highest coefficient of additive genetic variation (i.e. evolvability). Previous evidence suggests that eggshell colour is sexually selected in this species, males enhancing parental effort in clutches with higher colour variability and peak values. Eggshell colour could be driven by good-genes selection in pied flycatchers although further genetic studies should confirm this possibilityPeer reviewe