Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)

The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (~20,000 cal BP) than the OSL age measurement (~15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ~35,000 yr and ~34,000 yr, respectively. Rare-earth element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (~15,000 yr) is consistent with the age for the base of the dune (~14,500 yr). The younger OSL age for the top of the dune (~12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation

Antibiotic resistance in wastewater: Occurrence and fate ofEnterobacteriaceaeproducers of Class A and Class C β-lactamases

Antibiotics have been intensively used over the last decades in human and animal therapy and livestock, resulting in serious environmental and public health problems, namely due to the antibiotic residues concentration in wastewaters and to the development of antibiotic-resistant bacteria. This study aimed to access the contribution of some anthropological activities, namely urban household, hospital and a wastewater treatment plant, to the spread of antibiotic resistances in the treated wastewater released into the Mondego River, Coimbra, Portugal. Six sampling sites were selected in the wastewater network and in the river. The ampicillin-resistant Enterobacteriaceae of the water samples were enumerated, isolated and phenotypically characterized in relation to their resistance profile to 13 antibiotics. Some isolates were identified into species level and investigated for the presence of class A and class C -lactamases. Results revealed high frequency of resistance to the -lactam group, cefoxitin (53.5%), amoxicillin/clavulanic acid combination (43.5%), cefotaxime (22.7%), aztreonam (21.3) cefpirome (19.2%), ceftazidime (16.2%) and to the non--lactam group, trimethoprim/sulfamethoxazol (21.1%), tetracycline (18.2%), followed by ciprofloxacin (14.1%). The hospital effluent showed the higher rates of resistance to all antibiotic, except two (chloramphenicol and gentamicin). Similarly, higher resistance rates were detected in the wastewater treatment plant (WWTP) effluent compared with the untreated affluent. Regarding the multidrug resistance, the highest incidence was recorded in the hospital sewage and the lowest in the urban waste. The majority of the isolates altogether are potentially extended-spectrum -lactamases positive (ESBL(+)) (51.9%), followed by AmpC(+) (44.4%) and ESBL(+)/AmpC(+) (35.2%). The most prevalent genes among the potential ESBL producers were blaOXA (33.3%), blaTEM (24.1%) and blaCTX-M (5.6%) and among the AmpC producers were blaEBC (38.9%), blaFOX (1.9%) and blaCIT (1.9%). In conclusion, the hospital and the WWTP activities revealed to have the highest contribution to the spread of multidrug resistant bacteria in the study area. Such data is important for future management of the environmental and public health risk of these contaminants. This is the first embracing study in the water network of Coimbra region on the dissemination of antibiotic resistance determinants. Moreover, it is also the first report with the simultaneous detection of multiresistant bacteria producers of AmpC and ESBLs -lactamases in aquatic systems in Portugal.info:eu-repo/semantics/publishedVersio

First principles study of topological invariants of Weyl points in continuous media

In recent years there has been a great interest in topological photonics and protected edge states. Here, we present a first principles method to compute topological invariants of three-dimensional gapless phases. Our approach allows to calculate the topological charges of Weyl points through the efficient numerical computation of gap Chern numbers, which relies solely on the photonic Green's function of the system. We particularize the framework to the Weyl points that are found to emerge in a magnetized plasma due to the breaking of time reversal symmetry. We discuss the relevance of modelling nonlocality when considering the topological properties of continuous media such as the magnetized plasma. We find that for some of the considered material models the charge of the Weyl point can be expressed in terms of a difference of the gap Chern numbers of two-dimensional material subcomponents. Our theory may be extended to other three-dimensional topological phases, or to Floquet systems.Comment: 13 pages, 11 figure

H3K4me3 - dependent epigenetic memory regulates transcriptional reactivation in the oocyte

SELECTED ORAL COMMUNICATIONS, SESSION 52: EPIGENETIC PATTERN IN OOCYTE AND EMBRYO, Tuesday 16 June 2015. This article/study appears in: Abstract book of the 31st ESHRE Annual Meeting, Lisbon, Portugal, 14-17 June 2015.Study question: How does the oocyte regulate its transcriptional activity in light of its prolonged meiotic arrest? Summary answer: A histone methylation-mediated epigenetic memory programed by the demethylase KDM5 is required for the correct temporal reactivation of the oocyte's transcriptional activity. What is known already: During oogenesis oocytes transit from stages of transcriptional activity to those of transcriptional quiescence, and such transitions are believed to be essential for proper gamete formation. Although the temporal regulation of these transitions has been well documented across diverse organisms, the molecular mechanisms underlying these processes remain largely unknown.Funding by national/international organization(s) – Partly funded by Fundação para a Ciência e a Tecnologia

GLUT1-mediated glucose uptake plays a crucial role during Plasmodium hepatic infection.

Intracellular pathogens have evolved mechanisms to ensure their survival and development inside their host cells. Here, we show that glucose is a pivotal modulator of hepatic infection by the rodent malaria parasite Plasmodium berghei and that glucose uptake via the GLUT1 transporter is specifically enhanced in P. berghei-infected cells. We further show that ATP levels of cells containing developing parasites are decreased, which is known to enhance membrane GLUT1 activity. In addition, GLUT1 molecules are translocated to the membrane of the hepatic cell, increasing glucose uptake at later stages of infection. Chemical inhibition of GLUT1 activity leads to a decrease in glucose uptake and the consequent impairment of hepatic infection, both in vitro and in vivo. Our results reveal that changes in GLUT1 conformation and cellular localization seem to be part of an adaptive host response to maintain adequate cellular nutrition and energy levels, ensuring host cell survival and supporting P. berghei hepatic development

Innate immunity induced by Plasmodium liver infection inhibits malaria reinfections

© 2015 American Society for Microbiology. The authors have paid a fee to allow immediate free access to this article.Following transmission through a mosquito bite to the mammalian host, Plasmodium parasites first invade and replicate inside hepatocytes before infecting erythrocytes and causing malaria. The mechanisms limiting Plasmodium reinfections in humans living in regions of malaria endemicity have mainly been explored by studying the resistance induced by the blood stage of infection. However, epidemiologic studies have suggested that in high-transmission areas, preerythrocytic stages also activate host resistance to reinfection. This, along with the recent discovery that liver infections trigger a specific and effective type I interferon (IFN) response, prompted us to hypothesize that this pre-erythrocyte-stage-induced resistance is linked to liver innate immunity. Here, we combined experimental approaches and mathematical modeling to recapitulate field studies and understand the molecular basis behind such resistance. We present a newly established mouse reinfection model and demonstrate that rodent malaria liver-stage infection inhibits reinfection. This protection relies on the activation of innate immunity and involves the type I IFN response and the antimicrobial cytokine gamma IFN (IFN-γ). Importantly, mathematical simulations indicate that the predictions based on our experimental murine reinfection model fit available epidemiological data. Overall, our study revealed that liver-stage-induced innate immunity may contribute to the preerythrocytic resistance observed in humans in regions of malaria hyperendemicity.This work was supported by Fundação para a Ciência e Tecnologia (FCT, Portugal) grants PTDC-SAU-MIC-117060-2010 (to Miguel Prudêncio) and EXCL/IMI-MIC/0056/2012 (to M.M.M.). P.L. was supported by Fondation pour la Recherche Médicale and FCT (fellowship SFRH/BPD/41547/2007). P.M. was supported by FCT (fellowship SFRH/BD/71098/2010). Miguel Prudêncio and M.P.D. are supported by an Australian Research Council Discovery Grant (DP120100064). M.P.D. is an NHMRC Senior Research Fellow.info:eu-repo/semantics/publishedVersio

Dual-stage triterpenoids from an African medicinal plant targeting the malaria parasite

Sixteen triterpenoids (1–16), previously isolated from the aerial parts of the African medicinal plant Momordica balsamina or obtained by derivatization, were evaluated for their activity against liver stages of Plasmodium berghei, measuring the luminescence intensity in Huh-7 cells infected with a firefly lucif erase-expressing P. berghei line, PbGFP-Luccon. Toxicity of compounds (1–16) was assessed on the same cell line through the fluorescence measurement of cell confluency. The highest activity was displayed by a derivative bearing two acetyl residues, karavoate B (7), which led to a dose-dependent decrease in the P. berghei infection rate, exhibiting a very significant activity at the lowest concentration employed (1 lM) and no toxicity towards the Huh-7 cells. It is noteworthy that, in previous studies, this compound was found to be a strong inhibitor of blood-stages of Plasmodium falciparum, thus displaying a dual-stage antimalarial activity.info:eu-repo/semantics/publishedVersio

New 4-(N-cinnamoylbutyl)aminoacridines as potential multi-stage antiplasmodial leads

A novel family of 4-aminoacridine derivatives was obtained by linking this heteroaromatic core to different trans-cinnamic acids. The 4-(N-cinnamoylbutyl)aminoacridines obtained exhibited in vitro activity in the low- or sub-micromolar range against (i) hepatic stages of Plasmodium berghei, (ii) erythrocytic forms of Plasmodium falciparum, and (iii) early and mature gametocytes of Plasmodium falciparum. The most active compound, having a meta-fluorocinnamoyl group linked to the acridine core, was 20- and 120-fold more potent, respectively, against the hepatic and gametocyte stages of Plasmodium infection than the reference drug, primaquine. Moreover, no cytotoxicity towards mammalian and red blood cells at the concentrations tested was observed for any of the compounds under investigation. These novel conjugates represent promising leads for the development of new multi-target antiplasmodials.Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved