Impact of inorganic mercury on carotenoids in freshwater algae: Insights from single-cell resonance Raman spectroscopy.

The influence of inorganic mercury (Hg(II)) exposure on photosynthetic microorganisms and their pigments remains understudied. Here, we employed resonance Raman (RR) spectroscopy to investigate the responses of two freshwater phytoplankton species, the green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana to Hg(II) exposure. We selectively recorded the spectral RR signature of carotenoids in intact cells exposed to concentrations of 10 nM and 100 nM of Hg(II), representative for contaminated environment and unexposed control cells. A two-hour exposure of C. reinhardtii resulted in a slight decrease in lutein and ß-carotene levels, while total carotenoids RR band broadening, as revealed by the FWHM of the υ1(C=C) stretching mode from averaged RR spectra, suggested conformational changes in pigments. Higher Hg(II) concentration induced more pronounced conformational changes. Similarly, a two-hour exposure of C. meneghiniana resulted in slight decreased level of the fucoxanthin, while diadinoxanthin showed an opposite trend compared to control: when fucoxanthin decreased, diadinoxanthin increased under 10 nM Hg (II) exposure. At higher concentrations, the decrease in fucoxanthin was less pronounced, accompanied by a broadening of the band area, (with FHHM increased), indicating possible conformer occurrence in response to Hg-induced stress. The changes in the main carotenoid species of the two algae are species-specific, Hg(II) concentration-specific, and dependent on exposure time. The calculated spectral differences in absorbances from UV-VIS spectra of methanol extracts from each group supported the main findings obtained by RR, though with caution due to the selective extraction efficiency of the respective carotenoids. This study highlighted for a first time the capability of single-cell RR spectroscopy as a valuable tool for toxicity assessment and for comprehending early-stage alterations in carotenoid metabolism due to toxic metal exposure in vivo.

Working Memory Recovery in Adolescents with Concussion: Longitudinal fMRI Study.

Background: Understanding the behavioral and neural underpinnings of the post-concussion recovery of working memory function is critically important for improving clinical outcomes and adequately planning return-to-activity decisions. Previous studies provided inconsistent results due to small sample sizes and the use of a mixed population of participants who were at different post-injury time points. We aimed to examine working memory recovery during the first 6 months post-concussion in adolescents. Methods: We used functional magnetic resonance imaging (fMRI) to scan 45 concussed adolescents [CONCs] at baseline (<10 days post-concussion) and at 6 months post-concussion. Healthy control adolescents [HCs; n = 32] without a history of concussion were scanned once. During the scans, participants performed one-back and two-back working memory tasks with letters as the stimuli and angry, happy, neutral, and sad faces as distractors. Results: All affected adolescents were asymptomatic and cleared to return to activity 6 months after concussion. Working memory recovery was associated with faster and more accurate responses at 6 months vs. baseline (p-values < 0.05). It was also characterized by significant difficulty-related activation increases in the left inferior frontal gyrus (LIFG) and the left orbitofrontal cortex (LOFC) at 6 months vs. baseline. Although the activation differences between one-back and two-back were comparable between HCs and CONCs at 6 months, HCs had more pronounced activation in the LIFG than concussed adolescents. Conclusions: Post-concussion recovery is associated with significant performance improvements in speed and accuracy, as well as the normalization of brain responses in the LIFG and LOFC during the n-back task. The observed patterns of LOFC activation might reflect compensatory strategies to distribute neural processing and reduce neural fatigue post-concussion.

Exploring the subcellular distribution of mercury in green alga Chlamydomonas reinhardtii and diatom Cyclotella meneghiniana: A comparative study.

Mercury (Hg) is a priority pollutant of global concern because of its toxicity, its ability to bioaccumulate throughout the food web and reach significant concentrations in top predators. Phytoplankton bioconcentrate large amounts of Hg and play a key role in the entry of Hg into the aquatic food web. However, the subcellular distribution of Hg in freshwater phytoplankton, known to affect it toxicity and trophic transfer is understudied. The present study aimed at investigating the accumulation of inorganic Hg (iHg) and its subcellular distribution in freshwater phytoplankton species. To this end green alga Chlamydomonas reinhardtii and diatom Cyclotella meneghiniana were exposed to 10 and 100 nM of iHg for 2 h. The concentrations of Hg in the adsorbed, intracellular and subcellular (granules, debris, organelles, heat-stable peptides (HSP) and heat-denaturable proteins (HDP)) fractions were determined. The results showed that C. meneghiniana accumulated more Hg compared to C. reinhardtii at both iHg exposure concentrations (10 nM: 4.41 ± 0.74 vs. 1.10 ± 0.25 amol cell-1; 100 nM: 79.35 ± 10.78 vs. 38.31 ± 4.15 amol cell-1). The evaluation of the subcellular distribution of Hg, revealed that the majority of Hg was concentrated in the organelles fraction (59.7 % and 74.6 %) in the green algae. In the diatom, Hg was mainly found in the organelles (40.9 % and 33.3%) and in the HSP fractions (26.8 % and 40.1 %). The proportion of Hg in HDP fraction decreased in favor of the organelles fraction in C. reinhardtii when the exposure concentration increased, whereas the proportions in the debris and organelles fractions decreased in favor of HSP fraction in C. meneghiniana. This study provides pioneering information on the subcellular distribution of Hg within in freshwater phytoplankton, a knowledge that is essential to understand the toxicity and trophic transfer of Hg in contaminated aquatic environment.

Mercury species induce metabolic reprogramming in freshwater diatom Cyclotella meneghiniana.

Mercury is a hazardous pollutant of global concern. While advances have been made in identifying the detrimental effects caused by Hg species in phytoplankton, knowledge gaps remain regarding the metabolomic perturbations induced by inorganic mercury (Hg(II)) and monomethylmercury (MeHg) in these organisms. Diatoms represent a major phytoplankton group essential in various global biogeochemical cycles. The current study combined targeted metabolomics, bioaccumulation, and physiological response assays to investigate metabolic perturbations in diatom Cyclotella meneghiniana exposed for 2 h to nanomolar concentrations of Hg(II) and MeHg. Our findings highlight that such exposures induce reprogramming of the metabolism of amino acids, nucleotides, fatty acids, carboxylic acids and antioxidants. These alterations were primarily mercury-species dependent. MeHg exposure induced more pronounced reprogramming of the metabolism of diatoms than Hg(II), which led to less pronounced effects on ROS generation, membrane permeability and chlorophyll concentrations. Hg(II) treatments presented distinct physiological responses, with more robust metabolic perturbations at higher exposures. The present study provides first-time insights into the main metabolic alterations in diatom C. meneghiniana during short-term exposure to Hg species, deepening our understanding of the molecular basis of these perturbations.

Extended Finite Element Method (XFEM) Model for the Damage Mechanisms Present in Joints Bonded Using Adhesives Doped with Inorganic Fillers.

The use of adhesive bonding in diverse industries such as the automotive and aerospace sectors has grown considerably. In structural construction, adhesive joints provide a unique combination of low structural weight, high strength and stiffness, combined with a relatively simple and easily automated manufacturing method, characteristics that are ideal for the development of modern and highly efficient vehicles. In these applications, ensuring that the failure mode of a bonded joint is cohesive rather than adhesive is important since this failure mode is more controlled and easier to model and to predict. This work presents a numerical technique that enables the precise prediction of the bonded joint's behavior regarding not only its failure mode, but also the joint's strength, when inorganic fillers are added to the adhesive. To that end, hollow glass particles were introduced into an epoxy adhesive in different amounts, and a numerical study was carried out to simulate their influence on single lap joint specimens. The numerical results were compared against experimental ones, not only in terms of joint strength, but also their failure pattern. The neat adhesive, which showed 9% and 20% variations in terms of failure load and displacement, respectively. However, looking at the doped configurations, these presented smaller variations of about 2% and 10% for each respective variable. In all cases, by adding glass beads, crack initiation tended to change from adhesive to cohesive but with lower strength and ductility, correctly modeling the general experimental behavior as intended.

Different antihypertensive and metabolic responses to rostafuroxin in undernourished and normonourished male rats: Outcomes on bodily Na+ handling.

Hypertension is a pandemic nowadays. We aimed to investigate whether chronic undernutrition modifies the response to the antihypertensive drug rostafuroxin in juvenile hypertensive rats. Chronic undernutrition was induced in male rats using a multideficient diet known as the Regional Basic Diet (RBD), mimicking alimentary habits in impoverished regions worldwide. Animals were given RBD-or a control/CTRL normal diet for rodents-from weaning to 90 days, and rostafuroxin (1 mg/kg body mass) was orally administered from day 60 onwards. For the last 2 days, the rats were hosted in metabolic cages to measure food/energy, water, Na+ ingestion, and urinary volume. Rostafuroxin increased food/energy/Na+ intake in CTRL and RBD rats but had opposite effects on Na+ balance (intake minus urinary excretion). The drug normalized the decreased plasma Na+ concentration in RBD rats, increased urinary volume in RBD but not in CTRL, and decreased and increased urinary Na+ concentration in the RBD and CTRL groups, respectively. Rostafuroxin decreased the ouabain-sensitive (Na+ +K+ )ATPase and increased the ouabain-resistant Na+ -ATPase from proximal tubule cells in both groups and normalized the systolic blood pressure in RBD without effect in CTRL rats. We conclude that chronic undernutrition modifies the response of blood pressure and metabolic responses to rostafuroxin.

Osteoporosis screening using machine learning and electromagnetic waves.

Osteoporosis is a disease characterized by impairment of bone microarchitecture that causes high socioeconomic impacts in the world because of fractures and hospitalizations. Although dual-energy X-ray absorptiometry (DXA) is the gold standard for diagnosing the disease, access to DXA in developing countries is still limited due to its high cost, being present only in specialized hospitals. In this paper, we analyze the performance of Osseus, a low-cost portable device based on electromagnetic waves that measures the attenuation of the signal that crosses the medial phalanx of a patient's middle finger and was developed for osteoporosis screening. The analysis is carried out by predicting changes in bone mineral density using Osseus measurements and additional common risk factors used as input features to a set of supervised classification models, while the results from DXA are taken as target (real) values during the training of the machine learning algorithms. The dataset consisted of 505 patients who underwent osteoporosis screening with both devices (DXA and Osseus), of whom 21.8% were healthy and 78.2% had low bone mineral density or osteoporosis. A cross-validation with k-fold = 5 was considered in model training, while 20% of the whole dataset was used for testing. The obtained performance of the best model (Random Forest) presented a sensitivity of 0.853, a specificity of 0.879, and an F1 of 0.859. Since the Random Forest (RF) algorithm allows some interpretability of its results (through the impurity check), we were able to identify the most important variables in the classification of osteoporosis. The results showed that the most important variables were age, body mass index, and the signal attenuation provided by Osseus. The RF model, when used together with Osseus measurements, is effective in screening patients and facilitates the early diagnosis of osteoporosis. The main advantages of such early screening are the reduction of costs associated with exams, surgeries, treatments, and hospitalizations, as well as improved quality of life for patients.

Development of a Cyclic Voltammetry-Based Method for the Detection of Antigens and Antibodies as a Novel Strategy for Syphilis Diagnosis.

The improvement of laboratory diagnosis is a critical step for the reduction of syphilis cases around the world. In this paper, we present the development of an impedance-based method for detecting T. pallidum antigens and antibodies as an auxiliary tool for syphilis laboratory diagnosis. We evaluate the voltammetric signal obtained after incubation in carbon or gold nanoparticle-modified carbon electrodes in the presence or absence of Poly-L-Lysine. Our results indicate that the signal obtained from the electrodes was sufficient to distinguish between infected and non-infected samples immediately (T0') or 15 min (T15') after incubation, indicating its potential use as a point-of-care method as a screening strategy.

Angiotensin-(3-4) normalizes the elevated arterial blood pressure and abnormal Na+/energy handling associated with chronic undernutrition by counteracting the effects mediated by type 1 angiotensin II receptors.

We investigated the mechanisms by which chronic administration of a multideficient diet after weaning alters bodily Na+ handling, and culminates in high systolic blood pressure (SBP) at a juvenile age. From 28 to 92 days of age, weaned male Wistar rats were given a diet with low content and poor-quality protein, and low lipid, without vitamin supplementation, which mimics the diets consumed in impoverished regions worldwide. We measured food, energy and Na+ ingestion, together with urinary Na+ excretion, Na+ density (Na+ intake/energy intake), plasma Na+ concentration, SBP, and renal proximal tubule Na+-transporting ATPases. Undernourished rats aged 92 days had only one-third of the control body mass, lower plasma albumin, higher SBP, higher energy intake, and higher positive Na+ balance accompanied by decreased plasma Na+ concentration. Losartan or Ang-(3-4) normalized SBP, and the combination of the 2 substances induced an accentuated negative Na+ balance as a result of strong inhibition of Na+ ingestion. Na+ density in undernourished rats was higher than in control, irrespective of the treatment, and they had downregulated (Na++K+)ATPase and upregulated Na+-ATPase in proximal tubule cells, which returned to control levels after Losartan or Ang-(3-4). We conclude that Na+ density, not only Na+ ingestion, plays a central role in the pathophysiology of elevated SBP in chronically undernourished rats. The observations that Losartan and Ang-(3-4) normalized SBP together with negative Na+ balance give support to the proposal that Ang II⇒AT1R and Ang II⇒AT2R axes have opposite roles within the renin-angiotensin-aldosterone system of undernourished juvenile rats.

Simultaneous measurement of displacement and temperature using a balloon-like hybrid fiber sensor.

A fiber sensor based on a silica capillary in a balloon-like shape for simultaneous measurement of displacement and temperature is proposed and experimentally demonstrated. The sensor is fabricated by splicing a segment of a hollow-core fiber between two single-mode fibers (SMF) and by creating a balloon shape with the capillary at the top-center position. The SMF-capillary-SMF configuration excites an antiresonant (AR) guidance, and the balloon shape enhances the Mach-Zehnder interferometer (MZI). Experimental results show that, for a balloon length of 4.0 cm and a capillary length of 1.2 cm, the AR is insensitive to displacement and its sensitivity to temperature is 14.3 pm/°C, while the MZI has a sensitivity to displacement of 1.68 nm/mm in the range between 0 and 5 mm and a sensitivity to temperature of 28.6 pm/°C, twice the value of the AR. The proposed fiber sensor has only one sensing element in one configuration, which makes it simple to fabricate as well as low cost.

Characterization of the Effect of Hollow Glass Beads on the Mechanical Properties of Structural Adhesives.

Adhesives are extensively used in the automotive and aeronautical industries as they enable the creation of durable and light weight joints, with exceptional strength to weight ratios. The constant search for the means of adapting the mechanical performance of adhesives to each application has led to the use of several types of fillers to change their properties. Following a study on the effect of inorganic fillers, i.e., hollow glass beads, in the failure mechanisms of single lap joint's (SLJ), this work focuses on the response of the strength and fracture properties of structural adhesives to this filler. To this end, their tensile strength and mode I fracture properties were thoroughly analyzed by performing bulk tensile and double-cantilever beam (DCB) tests, at a quasi-static speed. The specimens were manufactured by adding different %v/v of filler to two epoxy-based crash resistant adhesives. Both adhesives have shown a negligible effect on the tensile strength, a decrease in strain at failure and critical energy release rate in mode I, as well as an increase of the Young's modulus, for higher % in volume of hollow glass beads. These phenomena were further analyzed recurring to scanning electron microscopy, and the concept of rule of mixtures.

Undernutrition - thirty years of the Regional Basic Diet: the legacy of Naíde Teodósio in different fields of knowledge.

Undernutrition is characterized by an imbalance of essential nutrients with an insufficient nutritional intake, a disorder in which the clinical manifestations in most cases are the result of the economic and social context in which the individual lives. In 1990, the study by the medical and humanitarian Naíde Teodósio (1915-2005) and coworkers, which formulated the Regional Basic Diet (RBD) model for inducing undernutrition, was published. This diet model took its origin from the observation of the dietary habits of families that inhabited impoverished areas from the Pernambuco State. RBD mimics an undernutrition framework that extends not only to the Brazilian population, but to populations in different regions worldwide. The studies based on RBD-induced deficiencies provide a better understanding of the impact of undernutrition on the pathophysiological mechanisms underlying the most diverse prevalent diseases. Indexed papers that are analyzed in this review focus on the importance of using RBD in different areas of knowledge. These papers reflect a new paradigm in translational medicine: they show how the study of pathology using the RBD model in animals over the past 30 years has and still can help scientists today, shedding light on the mechanisms of prevalent diseases that affect impoverished populations.

A Modular Workflow for Model Building, Analysis, and Parameter Estimation in Systems Biology and Neuroscience.

Neuroscience incorporates knowledge from a range of scales, from single molecules to brain wide neural networks. Modeling is a valuable tool in understanding processes at a single scale or the interactions between two adjacent scales and researchers use a variety of different software tools in the model building and analysis process. Here we focus on the scale of biochemical pathways, which is one of the main objects of study in systems biology. While systems biology is among the more standardized fields, conversion between different model formats and interoperability between various tools is still somewhat problematic. To offer our take on tackling these shortcomings and by keeping in mind the FAIR (findability, accessibility, interoperability, reusability) data principles, we have developed a workflow for building and analyzing biochemical pathway models, using pre-existing tools that could be utilized for the storage and refinement of models in all phases of development. We have chosen the SBtab format which allows the storage of biochemical models and associated data in a single file and provides a human readable set of syntax rules. Next, we implemented custom-made MATLAB® scripts to perform parameter estimation and global sensitivity analysis used in model refinement. Additionally, we have developed a web-based application for biochemical models that allows simulations with either a network free solver or stochastic solvers and incorporating geometry. Finally, we illustrate convertibility and use of a biochemical model in a biophysically detailed single neuron model by running multiscale simulations in NEURON. Using this workflow, we can simulate the same model in three different simulators, with a smooth conversion between the different model formats, enhancing the characterization of different aspects of the model.

Experimental Study of the Impact of Glass Beads on Adhesive Joint Strength and Its Failure Mechanism.

The use of modern structural adhesives provides a lightweight, practical, and high strength joining methodology, which is increasingly being adopted in the automotive and aeronautical sectors, among many others. However, the strict mechanical performance standards that must be met in these applications require a constant search for ways of improving the adhesives' behavior, which has led to the growing use of reinforcements as a way of improving the capabilities of bonded joints. The aim of this work was, thus, to analyze how the addition of inorganic fillers to the adhesive layer affects a joint's strength and its failure mechanism. To this end, single lap joint specimens with mild steel and high strength steel substrates were tested, at quasi-static speeds, and with different amounts of glass microspheres reinforcing two different structural adhesives. The experimental results indicated that the addition of glass particles reduced the joint performance for both substrates under study. Furthermore, the failure pattern was found to evolve from adhesive failure to a cohesive type of failure as the amount of glass particles present in the adhesive was increased.

Determination of the Intracellular Complexation of Inorganic and Methylmercury in Cyanobacterium Synechocystis sp. PCC 6803.

Understanding of mercury (Hg) complexation with low molecular weight (LMW) bioligands will help elucidate its speciation. In natural waters, the rate of this complexation is governed by physicochemical, geochemical, and biochemical parameters. However, the role of bioligands involved in Hg intracellular handling by aquatic microorganisms is not well documented. Here, we combine the use of isotopically labeled Hg species (inorganic and monomethylmercury, iHg and MeHg) with gas or liquid chromatography coupling to elemental and molecular mass spectrometry to explore the role of intracellular biogenic ligands involved in iHg and MeHg speciation in cyanobacterium Synechocystis sp. PCC 6803, a representative phytoplankton species. This approach allowed to track resulting metabolic and newly found intracellular Hg biocomplexes (e.g., organic thiols) in Synechocystis sp. PCC 6803 finding different intracellular Hg species binding affinities with both high and low molecular weight (HMW and LMW) bioligands in the exponential and stationary phase. Furthermore, the parallel detection with both elemental and molecular ionization sources allowed the sensitive detection and molecular identification of glutathione (GSH) as the main low molecular weight binding ligand to iHg ((GS)2-Hg) and MeHg (GS-MeHg) in the cytosolic fraction. Such a novel experimental approach expands our knowledge on the role of biogenic ligands involved in iHg and MeHg intracellular handling in cyanobacteria.

Subgroups of Foot-Ankle Movement Patterns Can Influence the Responsiveness to a Foot-Core Exercise Program: A Hierarchical Cluster Analysis.

The purpose of this study is to identify homogenous subgroups of foot-ankle (FA) kinematic patterns among recreational runners and further investigate whether differences in baseline movement patterns can influence the mechanical responses to a foot-core exercise intervention program. This is a secondary analysis of data from 85 participants of a randomized controlled trial (clinicaltrials.gov - NCT02306148) investigating the effects of an exercise-based therapeutic approach focused on FA complex. A validated skin marker-based multi-segment foot model was used to acquire kinematic data during the stance phase of treadmill running. Kinematic features were extracted from the time-series data using a principal component analysis, and the reduced data served as input for a hierarchical cluster analysis to identify subgroups of FA movement patterns. FA angle time series were compared between identified clusters and the mechanical effects of the foot-core exercise intervention was assessed for each subgroup. Two clusters of FA running patterns were identified, with cluster 1 (n = 36) presenting a pattern of forefoot abduction, while cluster 2 (n = 49) displayed deviations in the proximal segments, with a rearfoot adduction and midfoot abduction throughout the stance phase of running. Data from 29 runners who completed the intervention protocol were analyzed after 8-weeks of foot-core exercises, resulting in changes mainly in cluster 1 (n = 16) in the transverse plane, in which we observed a reduction in the forefoot abduction, an increase in the rearfoot adduction and an approximation of their pattern to the runners in cluster 2 (n = 13). The findings of this study may help guide individual-centered treatment strategies, taking into account their initial mechanical patterns.

Distinct oligodendrocyte populations have spatial preference and different responses to spinal cord injury.

Mature oligodendrocytes (MOLs) show transcriptional heterogeneity, the functional consequences of which are unclear. MOL heterogeneity might correlate with the local environment or their interactions with different neuron types. Here, we show that distinct MOL populations have spatial preference in the mammalian central nervous system (CNS). We found that MOL type 2 (MOL2) is enriched in the spinal cord when compared to the brain, while MOL types 5 and 6 (MOL5/6) increase their contribution to the OL lineage with age in all analyzed regions. MOL2 and MOL5/6 also have distinct spatial preference in the spinal cord regions where motor and sensory tracts run. OL progenitor cells (OPCs) are not specified into distinct MOL populations during development, excluding a major contribution of OPC intrinsic mechanisms determining MOL heterogeneity. In disease, MOL2 and MOL5/6 present different susceptibility during the chronic phase following traumatic spinal cord injury. Our results demonstrate that the distinct MOL populations have different spatial preference and different responses to disease.

Diversity of Bacterial Biosynthetic Genes in Maritime Antarctica.

Bacterial natural products (NPs) are still a major source of new drug leads. Polyketides (PKs) and non-ribosomal peptides (NRP) are two pharmaceutically important families of NPs and recent studies have revealed Antarctica to harbor endemic polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, likely to be involved in the production of novel metabolites. Despite this, the diversity of secondary metabolites genes in Antarctica is still poorly explored. In this study, a computational bioprospection approach was employed to study the diversity and identity of PKS and NRPS genes to one of the most biodiverse areas in maritime Antarctica-Maxwell Bay. Amplicon sequencing of soil samples targeting ketosynthase (KS) and adenylation (AD) domains of PKS and NRPS genes, respectively, revealed abundant and unexplored chemical diversity in this peninsula. About 20% of AD domain sequences were only distantly related to characterized biosynthetic genes. Several PKS and NRPS genes were found to be closely associated to recently described metabolites including those from uncultured and candidate phyla. The combination of new approaches in computational biology and new culture-dependent and -independent strategies is thus critical for the recovery of the potential novel chemistry encoded in Antarctica microorganisms.

Red deer in Iberia: Molecular ecological studies in a southern refugium and inferences on European postglacial colonization history.

The red deer (Cervus elaphus) is a widespread wild ungulate in Europe that has suffered strong anthropogenic impacts over their distribution during the last centuries, but also at the present time, due its economic importance as a game species. Here we focus on the evolutionary history of the red deer in Iberia, one of the three main southern refugial areas for temperate species in Europe, and addressed the hypothesis of a cryptic refugia at higher latitudes during the Last Glacial Maximum (LGM). A total of 911 individuals were sampled, genotyped for 34 microsatellites specifically developed for red deer and sequenced for a fragment of 670 bp of the mitochondrial (mtDNA) D-loop. The results were combined with published mtDNA sequences, and integrated with species distribution models and historical European paleo-distribution data, in order to further examine the alternative glacial refugial models and the influence of cryptic refugia on European postglacial colonization history. Clear genetic differentiation between Iberian and European contemporary populations was observed at nuclear and mtDNA levels, despite the mtDNA haplotypes central to the phylogenetic network are present across western Europe (including Iberia) suggesting a panmictic population in the past. Species distribution models, fossil records and genetic data support a timing of divergence between Iberian and European populations that overlap with the LGM. A notable population structure was also found within the Iberian Peninsula, although several populations displayed high levels of admixture as a consequence of recent red deer translocations. Five D-loop sub-lineages were found in Iberia that belong to the Western European mtDNA lineage, while there were four main clusters based on analysis of nuclear markers. Regarding glacial refugial models, our findings provide detailed support for the hypothesis that red deer may have persisted in cryptic northern refugia in western Europe during the LGM, most likely in southern France, southern Ireland, or in a region between them (continental shelf), and these regions were the source of individuals during the European re-colonization. This evidence heightens the importance of conserving the high mitochondrial and nuclear diversity currently observed in Iberian populations.

Effect of calcium sources in the diets of adult cats on urinary parameters and acid-base balance / Efeitos das fontes de cálcio na dieta de gatos adultos sobre parâmetros urinários e equilíbrio ácido-básico

Calcium is a macroelement that is part of the mineral composition of the diet of companion animals, and is considered a cation of strong alkalizing power, increasing urinary pH. Calcium salts have different solubilities and depending on the anion to which calcium is associated with, it can be more or less absorbed, modifying the pH of the urine. The aim of this study was to evaluate the efficiency of calcium sources on alkalinization of urinary pH, as well as excretion of urinary electrolytes and acid-base balance of adult cats. An extruded diet for cats was selected, and had 160mEq/kg of calcium from the sources of either calcium carbonate (CaCO3) or calcium gluconate (C12H22CaO14) added. In the control treatment there was no addition of calcium sources, resulting in three treatments. Nine adult cats were used, mixed breed, in two experimental periods, with six replicates per treatment. Animal average age was 4±1.3 years old and average weight was 3.96±0.71kg. The cats remained in metabolic cages for an adaptation period of seven days, followed by six days of urine total collection, with volume, density, pH and calcium concentration (g/d) measurements. The acid-base balance was studied by blood gas analysis of venous blood. The two sources of calcium alkalinized the urine (P<0.001). However, calcium gluconate had less alkalinization power compared to the calcium carbonate (P<0.05). Urinary calcium was not affected by treatments, and represented less than 0.5% of calcium intake. The experiment showed that calcium, although an alkaline cation and considered strong influencer of the EB of the diet, cannot be evaluated individually, because depending on its associated anion it may have greater or lesser influence on cats urine pH.(AU)

O cálcio (Ca) é um macroelemento que faz parte da composição mineral da dieta de animais de companhia. Este macroelemento é considerado um cátion de forte capacidade alcalinizante e, de acordo com a fonte e quantidade inclusa, pode aumentar o pH urinário. Os sais de cálcio têm diferentes solubilidades e dependendo do ânion ao qual o cálcio está associado, pode ser mais ou menos absorvido e assim, alterar o pH da urina. O objetivo deste estudo foi avaliar os efeitos de duas fontes de cálcio na alcalinização do pH urinário, bem como a excreção de eletrólitos urinários e o equilíbrio ácido-básico de felinos. Foi selecionada uma dieta extrusada para gatos e adicionados 160mEq/kg de cálcio das fontes carbonato de cálcio (CaCO3) ou gluconato de cálcio (C12H22CaO14). No tratamento controle, não houve adição de fontes de cálcio. Foram utilizados nove gatos adultos, de raças mistas, em dois períodos experimentais, com seis repetições por tratamento. Os animais apresentavam idade média de 4,0±1,3 anos e peso corporal médio de 3,96±0,71kg. Estes permaneceram em gaiolas metabólicas em período de adaptação durante sete dias, seguido de coleta total de urina durante seis dias. Nestas amostras foram aferidos o volume, densidade, pH e concentração de cálcio (g/d). O equilíbrio ácido-básico foi avaliado por hemogasometria em amostras de sangue venoso. As duas fontes de cálcio alcalinizaram a urina (P<0,001). No entanto, o gluconato de cálcio apresentou menor potencial de alcalinização em comparação ao carbonato de cálcio (P<0,05). O cálcio urinário não foi afetado pelos tratamentos e representou menos de 0,5% da ingestão de Ca. O experimento demonstrou que o cálcio, apesar de ser um cátion alcalinizante e influenciador do EB da dieta, não pode ser avaliado individualmente, porque dependendo do ânion associado, pode apresentar maior ou menor influência no pH da urina de gatos.(AU)