Genomic Comparative of Pseudomonas aeruginosa Small Colony Variant, Mucoid and Non-mucoid Phenotypes Obtained from a Patient with Cystic Fibrosis During Respiratory Exacerbations.

Pseudomonas aeruginosa, the most prevalent opportunistic pathogen in chronic obstructive pulmonary disease, associated with high morbidity and mortality in patients with cystic fibrosis (CF), is practically impossible to be eradicated from the airways in chronicity. Its extraordinary genomic plasticity is possibly associated with high antimicrobial resistance, virulence factors, and its phenotypic diversity. The occurrence of P. aeruginosa isolates promoting airway infection, showing mucoid, non-mucoid, and small colony variant (SCV) phenotypes, was observed simultaneously, in the present study, in sputum cultures obtained from a male CF young patient with chronic pulmonary infection for over a decade. The isolates belonged to a new ST (2744) were obtained in two moments of exacerbation of the respiratory disease, in which he was hospitalized. Genetic background and phenotypic analysis indicated that the isolates exhibited multi- and pan-antimicrobial resistant profiles, as well as non-susceptible to polymyxin and predominantly hypermutable (HPM) phenotypes. Whole genome sequencing showed variations in genome sizes, coding sequences and their determinants of resistance and virulence. The annotated genomes were compared for antimicrobial resistance, hypermutability, and SCV characteristics. We highlight the lack of reported genetic determinants of SCV emergence and HPM phenotypes, which can be explained in part due to the very short time between collections of isolates. To the best of our knowledge, this is the first report of genome sequencing of P. aeruginosa SCV from a CF patient in Brazil.

Susceptibility of solid organ transplant recipients to viral pathogens with zoonotic potential: A mini-review.

A substantial number of zoonotic diseases are caused by viral pathogens, representing a significant menace to public health, particularly to susceptible populations, such as pregnant women, the elderly, and immunocompromised individuals. Individuals who have undergone solid organ transplantation frequently experience immunosuppression, to prevent organ rejection, and, thus are more prone to opportunistic infections. Furthermore, the reactivation of dormant viruses can threaten transplant recipients and organ viability. This mini-review examines the up-to-date literature covering potential zoonotic and organ rejection-relevant viruses in solid organ transplant recipients. A comprehensive list of viruses with zoonotic potential is highlighted and the most important clinical outcomes in patients undergoing transplantation are described. Moreover, this mini-review calls attention to complex multifactorial events predisposing viral coinfections and the need for continuous health surveillance and research to understand better viral pathogens' transmission and pathophysiology dynamics in transplanted individuals.

Genetic determinants of antimicrobial resistance in polymyxin B resistant Pseudomonas aeruginosa isolated from airways of patients with cystic fibrosis.

Pseudomonas aeruginosa is the main pathogen associated with pulmonary exacerbation in patients with cystic fibrosis (CF). CF is a multisystemic genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene, which mainly affects pulmonary function. P. aeruginosa isolated from individuals with CF in Brazil is not commonly associated with multidrug resistance (MDR), especially when compared to global occurrence, where the presence of epidemic clones, capable of expressing resistance to several drugs, is often reported. Due to the recent observations of MDR isolates of P. aeruginosa in our centers, combined with these characteristics, whole-genome sequencing was employed for analyses related to antimicrobial resistance, plasmid identification, search for phages, and characterization of CF clones. All isolates in this study were polymyxin B resistant, exhibiting diverse mutations and reduced susceptibility to carbapenems. Alterations in mexZ can result in the overexpression of the MexXY efflux pump. Mutations in oprD, pmrB, parS, gyrA and parC may confer reduced susceptibility to antimicrobials by affecting permeability, as observed in phenotypic tests. The phage findings led to the assumption of horizontal genetic transfer, implicating dissemination between P. aeruginosa isolates. New sequence types were described, and none of the isolates showed an association with epidemic CF clones. Analysis of the genetic context of P. aeruginosa resistance to polymyxin B allowed us to understand the different mechanisms of resistance to antimicrobials, in addition to subsidizing the understanding of possible relationships with epidemic strains that circulate among individuals with CF observed in other countries.

Microplastics and nanoplastics in haemodialysis waters: Emerging threats to be in our radar.

Microplastics are present in the environment, in drinking water, in human blood and there is evidence of nanoplastics in tap water. The objective of this work was to analyze the possibility of hemodialysis patients being contaminated by micro and nanoplastics (MNPs) during dialysis treatment. The motivation for this investigation is the fact that hemodialysis patients use about 300-600 L of drinking water per week, which may be contaminated by MNPs. A literature review, a field investigation in a London hospital and an estimation of MNPs intake in patients were carried out. The results showed potential points of risk of contamination of patients by MNPs in hemodialysis. It was also estimated that for a filtration efficiency of 99 % for MNPs, the amount of microplastics that can penetrate the kidneys of patients is 0.0021-3768 particles/week. The assessment concludes that hemodialysis patients are at high risk of MNP contamination.

Evaluating the cost implications of integrating SARS-CoV-2 genome sequencing for infection prevention and control investigation of nosocomial transmission within hospitals.

BACKGROUND: The COG-UK hospital-onset COVID-19 infection (HOCI) trial evaluated the impact of SARS-CoV-2 whole-genome sequencing (WGS) on acute infection, prevention, and control (IPC) investigation of nosocomial transmission within hospitals. AIM: To estimate the cost implications of using the information from the sequencing reporting tool (SRT), used to determine likelihood of nosocomial infection in IPC practice. METHODS: A micro-costing approach for SARS-CoV-2 WGS was conducted. Data on IPC management resource use and costs were collected from interviews with IPC teams from 14 participating sites and used to assign cost estimates for IPC activities as collected in the trial. Activities included IPC-specific actions following a suspicion of healthcare-associated infection (HAI) or outbreak, as well as changes to practice following the return of data via SRT. FINDINGS: The mean per-sample costs of SARS-CoV-2 sequencing were estimated at £77.10 for rapid and £66.94 for longer turnaround phases. Over the three-month interventional phases, the total management costs of IPC-defined HAIs and outbreak events across the sites were estimated at £225,070 and £416,447, respectively. The main cost drivers were bed-days lost due to ward closures because of outbreaks, followed by outbreak meetings and bed-days lost due to cohorting contacts. Actioning SRTs, the cost of HAIs increased by £5,178 due to unidentified cases and the cost of outbreaks decreased by £11,246 as SRTs excluded hospital outbreaks. CONCLUSION: Although SARS-CoV-2 WGS adds to the total IPC management cost, additional information provided could balance out the additional cost, depending on identified design improvements and effective deployment.

Toxicological aspect of water treated by chlorine-based advanced oxidation processes: A review.

As well established in the literature, residual toxicity is an important parameter for evaluating the sanitary and environmental safety of water treatment processes, and this parameter becomes even more crucial when chlorine-based processes are applied for water treatment. Eliminating initial toxicity or preventing its increase after water treatment remains a huge challenge mainly due to the formation of highly toxic disinfection by-products (DBPs) that stem from the degradation of organic contaminants or the interaction of the chlorine-based oxidants with different matrix components. In this review, we present a comprehensive discussion regarding the toxicological aspects of water treated using chlorine-based advanced oxidation processes (AOPs) and the recent findings related to the factors influencing toxicity, and provide directions for future research in the area. The review begins by shedding light on the advances made in the application of free chlorine AOPs and the findings from studies conducted using electrochemical technologies based on free chlorine generation. We then delve into the insights and contributions brought to the fore regarding the application of NH2Cl- and ClO2-based treatment processes. Finally, we broaden our discussion by evaluating the toxicological assays and predictive models employed in the study of residual toxicity and provide an overview of the findings reported to date on this subject matter, while giving useful insights and directions for future research on the topic.

Management of a large outbreak of COVID-19 at a British Army training centre: lessons for the future.

INTRODUCTION: The COVID-19 pandemic has posed major challenges for infection control within training centres, both civilian and military. Here we present a narrative review of an outbreak that occurred at the Royal Military Academy Sandhurst (RMAS) in January-March 2021, in the context of the circulating, highly transmissible SARS-CoV-2 variant B.1.1.7. METHODS: Testing for SARS-CoV-2 was performed using a combination of reverse transcriptase PCR and Lateral Flow Devices (LFDs). Testing and isolation procedures were conducted in line with a pre-established symptom stratification system. Genomic sequencing was performed on 10 sample isolates. RESULTS: By the end of the outbreak, 185 cases (153 Officer Cadets, 32 permanent staff) had contracted confirmed COVID-19. This represented 15% of the total RMAS population. This resulted in 0 deaths and 0 hospitalisations, but due to necessary isolation procedures did represent an estimated 12 959 person-days of lost training. 9 of 10 (90%) of sequenced isolates had a reportable lineage. All of those reported were found to be the Alpha lineage B.1.1.7. CONCLUSIONS: We discuss the key lessons learnt from the after-action review by the Incident Management Team. These include the importance of multidisciplinary working, the utility of sync matrices to monitor outbreaks in real time, issues around Officer Cadets reporting symptoms, timing of high-risk training activities, infrastructure and use of LFDs. COVID-19 represents a vital learning opportunity to minimise the impact of potential future pandemics, which may produce considerably higher morbidity and mortality in military populations.

Methanolic Extracts of Chiococca alba in Aedes aegypti Biorational Management: Larvicidal and Repellent Potential, and Selectivity against Non-Target Organisms.

The use of formulations containing botanical products for controlling insects that vector human and animal diseases has increased in recent years. Plant extracts seem to offer fewer risks to the environment and to human health without reducing the application strategy's efficacy when compared to synthetic and conventional insecticides and repellents. Here, we evaluated the potential of extracts obtained from caninana, Chiococca alba (L.) Hitchc. (Rubiaceae), plants as a tool to be integrated into the management of Aedes aegypti, one of the principal vectors for the transmission of arborviruses in humans. We assessed the larvicidal and repellence performance against adult mosquitoes and evaluated the potential undesired effects of the extracts on non-target organisms. We assessed the susceptibility and predatory abilities of the nymphs of Belostoma anurum, a naturally occurring mosquito larva predator, and evaluated the C. alba extract's cytotoxic effects in mammalian cell lines. Our chromatographic analysis revealed 18 compounds, including rutin, naringin, myricetin, morin, and quercetin. The methanolic extracts of C. alba showed larvicidal (LC50 = 82 (72-94) mg/mL) activity without killing or affecting the abilities of B. anurum to prey upon mosquito larvae. Our in silico predictions revealed the molecular interactions between rutin and the AeagOBP1 receptor to be one possible mechanism for the repellent potential recorded for formulations containing C. alba extracts. Low cytotoxicity against mammalian cell lines reinforces the selectivity of C. alba extracts. Collectively, our findings highlight the potential of C. alba and one of its constituents (rutin) as alternative tools to be integrated into the management of A. aegypti mosquitoes.

Nosocomial or not? A combined epidemiological and genomic investigation to understand hospital-acquired COVID-19 infection on an elderly care ward.

BACKGROUND: COVID-19 has the potential to cause outbreaks in hospitals. Given the comorbid and elderly cohort of patients hospitalized, hospital-acquired COVID-19 infection is often fatal. Pathogen genome sequencing is becoming increasingly important in infection prevention and control (IPC). AIM: To inform the understanding of in-hospital SARS-CoV-2 transmission in order to improve IPC practices and to inform the future development of virological testing for IPC. METHODS: Patients detected COVID-19 positive by polymerase chain reaction on Ward A in April and May 2020 were included with contact tracing to identify other potential cases. Genome sequencing was undertaken for a subgroup of cases. Epidemiological, genomic, and cluster analyses were performed to describe the epidemiology and to identify factors contributing to the outbreak. FINDINGS: Fourteen cases were identified on Ward A. Contact tracing identified 16 further patient cases; in addition, eight healthcare workers (HCWs) were identified as being COVID-19 positive through a round of asymptomatic testing. Genome sequencing of 16 of these cases identified viral genomes differing by two single nucleotide polymorphisms or fewer, with further cluster analysis identifying two groups of infection (a five-person group and a six-person group). CONCLUSION: Despite the temporal relationship of cases, genome sequencing identified that not all cases shared transmission events. However, 11 samples were found to be closely related and these likely represented in-hospital transmission. This included three HCWs, thereby confirming transmission between patients and HCWs.

Recognizing the enemy: do predator cues influence hatching in Neotropical annual killifish?

Annual fish species have evolved complex adaptations to survive in temporary wetlands. The main adaptation of these fish is the ability to produce embryos that survive dry periods. Embryo development of this fish can show variation at multiple levels influenced by many environmental factors, such as photoperiod and temperature. Predator cues are another factor that can influence the embryonic stage. One way in which annual fish could adapt to predators is by using risk-spreading strategies (through bet-hedging). Nonetheless, this strategy depends on the coevolutionary history between predators and preys and on the degree of environmental unpredictability, resulting in different responses across different species. This study investigated the influence of predator cues on the embryonic development and hatching of two Austrolebias species that inhabit ponds that present differences in hydroperiod and the risk of predator presence. The results confirmed a differentiated response between the two annual fish species tested, corroborating the modulation of hatching against the risk of predation by native predatory fish. The authors further showed that development times varied between the two annual fish species, regardless of the presence of predators. They highlight that the variation in embryonic development is strongly affected by different levels of hydroperiod unpredictability faced by the two species. To unravel finer-scale local adaptations in the annual fish embryo development, future studies should focus on a region with greater spatial gradient.

Anabolic androgenic steroid-induced hypogonadism, a reversible condition in male individuals? A systematic review.

The anabolic-androgenic steroids (AAS) are clinically used as an androgen replacement, in hypogonadism treatment, to induce puberty, and also in the treatment of chronic degenerative diseases. The AAS use out of clinical context is becoming massively, being used merely for aesthetic reasons. AAS abuse may cause severe disarrangement on the HPG axis and generate a significant decrease in testosterone synthesis and secretion by the testes. This review aims to evaluate whether the hypogonadism induced by AAS abuse is reversible and under what circumstances the reversibility is possible. For this, PRISMA guidelines and several databases are used between July and September 2020. Altogether, this systematic review identified and analysed 179 cases of AAS users. Of these, 168 cases had the hypogonadism clearly diagnosed and proven to be linked exclusively to AAS abuse. However, between these 168 cases, only 38 cases presented fully known outcomes and among these, merely in 4, the hypogonadism was completely reversible (2 based on drug therapy) with HPG axis recovery. In conclusion, this review presents evidences that AAS-induced hypogonadism is a seriously underestimated problem, and in the majority of cases, full recovery is very difficult to succeed.

Implementation of a fetal ultrasound telemedicine service: women's views and family costs.

BACKGROUND: The complexity of fetal medicine (FM) referrals that can be managed within obstetric units is dependent on the availability of specialist ultrasound expertise. Telemedicine can effectively transfer real-time ultrasound images via video-conferencing. We report the successful introduction of a fetal ultrasound telemedicine service linking a specialist fetal medicine (FM) centre and a remote obstetric unit. METHODS: Over a four-year period from October 2015, all women referred for FM consultation from the obstetric unit were seen via telemedicine, excluding cases where invasive testing, intrauterine therapy or cardiac anomalies were anticipated. The outcomes measured included the indication for FM referral; scan duration and image and sound quality during the consultation. Women's perceptions of the telemedicine consultation and estimated costs to attend the FM centre were measured by a structured questionnaire completed following the first telemedicine appointment during the Phase 1 of the project. RESULTS: Overall, 297 women had a telemedicine consultation during Phase 1 (pilot and evaluation) and Phase 2 (embedding and adoption) of the project, which covered a 4 year period 34 women completed questionnaires during the Phase 1 of the study. Travel to the telemedicine consultation took a median (range) time of 20 min (4150), in comparison to an estimated journey of 230 min (120,450) to the FM centre. On average, women would have spent approximately £28 to travel to the FM centre per visit. The overall costs for the woman and her partner/ friend to attend the FM centre was estimated to be £439. Women were generally satisfied with the service and valued the opportunity to have a FM consultation locally. CONCLUSIONS: We have demonstrated that a fetal ultrasound telemedicine service can be successfully introduced to provide FM ultrasound of sufficient quality to allow fetal diagnosis and specialist consultation with parents. Furthermore, the service is acceptable to parents, has shown a reduction in family costs and journey times.

Carbapenem-Resistant Pseudomonas aeruginosa in Chronic Lung Infection: Current Resistance Profile and Hypermutability in Patients with Cystic Fibrosis.

Pseudomonas aeruginosa is associated with chronic and progressive lung disease and is closely related to increased morbidity and mortality in cystic fibrosis (CF) patients. Hypermutable (HPM) P. aeruginosa isolates have been described in these patients and are usually associated with antibiotic resistance. This study aimed to investigate the occurrence of carbapenem resistance and hypermutable phenotype in 179 P. aeruginosa isolates from 8 chronically CF patients assisted at two reference centers in Rio de Janeiro, Brazil. Using disk diffusion test, non-susceptible (NS) rates higher than 40% were observed for imipenem, amikacin, and gentamicin. A total of 79 isolates (44.1%), 71 (39.6%), and 8 (4.4%) were classified as carbapenem-resistant (CR resistance to at least one carbapenem), multidrug-resistant (MDR), and extensively drug-resistant (XDR), respectively. Minimal inhibitory concentration was determined for 79 CR P. aeruginosa and showed the following variations: 4 and 128 µg/mL to imipenem, 4 and 64 µg/mL to meropenem, and 4 and ≥ 32 µg/mL to doripenem. We have found only four (2.23%) HPM isolates from 4 patients. Analyzing the genetic relationship among the HPM isolates, 3 pulsed-field gel electrophoresis/pulsotypes (D, M, and J) were observed. Only M pulsotype was recovered from two patients in different years. Polymerase chain reaction screening for blaGES, blaIMP, blaKPC, blaNDM, blaOXA-48, blaSPM, and blaVIM genes was performed for all CR isolates and none of them were positive. Our results demonstrate a high occurrence of CR and MDR P. aeruginosa of CF patients follow-up in both centers studied, while the presence of HPM is still unusual.

Biomathematical models for genetic diversity analyses in complete genomes of SARS-CoV-2

In this work, we evaluated the levels of genetic diversity in 38 complete genomes of SARS-CoV-2, publicly available on the National Center for Biotechnology Information (NCBI) platform and from six countries in South America (Brazil, Chile, Peru, Colombia, Uruguay and Venezuela with 16, 11, 1, 1, 1, 7 haplotypes, respectively), all with an extension of 29,906 bp and Phred values [≥] 40. These haplotypes were previously used for phylogenetic analyses, following the alignment protocols of the MEGA X software; where all gaps and unconserved sites were extracted for the construction of phylogenetic trees. The specific methodologies for Paired FST estimators, Molecular Variance (AMOVA), Genetic Distance, mismatch, demographic and spatial expansion analyses, molecular diversity and evolutionary divergence time analyses, were obtained using 20,000 random permutation.

The relationship of pork carcass weight and leanness parameters in the Ontario commercial pork industry.

This study aimed to examine the correlation of carcass weight, fat depth, muscle depth, and predicted lean yield in commercial pigs. Data were collected on 850,819 pork carcasses from the same pork processing facility between October 2017 and September 2018. Hot carcass weight was reported following slaughter as a head-on weight; while fat and muscle depth were measured with a Destron PG-100 probe and used for the calculation of predicted lean yield based on the Canadian Lean Yield (CLY) equation [CLY (%) = 68.1863 - (0.7833 × fat depth) + (0.0689 × muscle depth) + (0.0080 × fat depth2) - (0.0002 × muscle depth2) + (0.0006 × fat depth × muscle depth)]. Descriptive statistics, regression equations including coefficients of determination, and Pearson product moment correlation coefficients (when assumptions for linearity were met) and Spearman's rank-order correlation coefficients (when assumptions for linearity were not met) were calculated for attributes using SigmaPlot, version 11 (Systat Software, Inc., San Jose, CA). Weak positive correlation was observed between hot carcass weight and fat depth (r = 0.289; P < 0.0001), and between hot carcass weight and muscle depth (r = 0.176; P < 0.0001). Weak negative correlations were observed between hot carcass weight and predicted lean yield (r = -0.235; P < 0.0001), and between fat depth and muscle depth (r = -0.148; P < 0.0001). Upon investigation of relationships between fat depth and predicted lean yield, and between muscle depth and predicted lean yield using scatter plots, it was determined that these relationships were not linear and therefore the assumptions of Pearson product moment correlation were not met. Thus, these relationships were expressed as nonlinear functions and Spearman's rank-order correlation coefficients were used. A strong negative correlation was observed between fat depth and predicted lean yield (r = -0.960; P < 0.0001), and a moderate positive correlation was observed between muscle depth and predicted lean yield (r = 0.406; P < 0.0001). Results from this dataset revealed that hot carcass weight was generally weakly correlated (r < |0.35|) with fat depth, muscle depth, and predicted lean yield. Therefore, it was concluded that there were no consistent weight thresholds where pigs were fatter or heavier muscled.

Characterization of pulmonary immune responses to hyperoxia by high-dimensional mass cytometry analyses.

Prolonged exposure to hyperoxia has deleterious effects on the lung, provoking both inflammation and alveolar injury. The elements of hyperoxic injury, which result in high rates of lethality in experimental models, are thought to include multicellular immune responses. To characterize these alterations in immune cell populations, we performed time-of-flight mass cytometry (CyTOF) analysis of CD45-expressing immune cells in whole lung parenchyma and the bronchoalveolar space of mice, exposed to 48 hours of hyperoxia together with normoxic controls. At the tested time point, hyperoxia exposure resulted in decreased abundance of immunoregulatory populations (regulatory B cells, myeloid regulatory cells) in lung parenchyma and markedly decreased proliferation rates of myeloid regulatory cells, monocytes and alveolar macrophages. Additionally, hyperoxia caused a shift in the phenotype of alveolar macrophages, increasing proportion of cells with elevated CD68, CD44, CD11c, PD-L1, and CD205 expression levels. These changes occurred in the absence of histologically evident alveolar damage and abundance of neutrophils in the parenchyma or alveolar space did not change at these time points. Collectively, these findings demonstrate that pulmonary response to hyperoxia involves marked changes in specific subsets of myeloid and lymphoid populations. These findings have important implications for therapeutic targeting in acute lung injury.

Degradation of antibiotic ciprofloxacin by different AOP systems using electrochemically generated hydrogen peroxide.

The present work reports the degradation of the antibiotic ciprofloxacin (CIP) by different advanced oxidative process systems (UV; Anodic Oxidation; H2O2; H2O2/UV; H2O2/Fe2+ and H2O2/UV/Fe2+) in an electrochemical cell using gas diffusion electrode (GDE) for the synthesis of hydrogen peroxide. CIP degradation and mineralization were evaluated by high efficiency liquid chromatography (HPLC) and total organic carbon (TOC) techniques. Of all the systems investigated, the photoelectro-Fenton system presented the best degradation efficiency; this system promoted highly significant mineralization percentages of 54.8% and 84.6% in 90 and 360 min, and relatively lower energy consumption rates of 4110.0 and 9808.2 kWh kg-1 TOC, respectively. In 6 h period of experiment, the main degradation products of ciprofloxacin were identified, and the aliphatic acids obtained helped confirm the rupture of the aromatic ring. The application of the photoelectro-Fenton process with in situ eletroctrogeneration of H2O2 using GDE has proved to be suitably promising for the treatment of organic pollutants.

Effect of high-fluoride dentifrice and bracket bonding composite material on enamel demineralization in situ.

OBJECTIVE: This in situ study evaluated the effect of high-fluoride dentifrice (5000 µg F-/g) and fluoride-containing bonding composite resin on enamel demineralization adjacent to orthodontic brackets. METHODS: Ten volunteers wore palatal appliances containing bovine enamel blocks with metallic brackets bonded with fluoride-free or fluoride-containing composite resin. During three phases of 14 days each, three dentifrices with different fluoride concentrations (0, 1100, and 5000 µg F-/g) were tested. The cariogenic challenge consisted of 20% sucrose solution dripped 8x/day onto the dental blocks. At the end of each phase, biofilm formed was collected for fluoride analysis. Cross section hardness was performed in enamel blocks, and the lesion area was calculated. Data were analyzed by two-way ANOVA followed by Tukey post hoc test (α = 5%). RESULTS: The only signicant factor for all the variables under study was the dentifrice. Smaller lesion area and higher fluoride concentration on biofilm were found in 5000 µg F-/g group, irrespective of bonding composite resin (p < 0.001). Neither bracket-bonding composite resin nor the interaction between the factors was statistically significant (p > 0.05) for all the variables. CONCLUSION: High-fluoride dentifrice is effective in reducing demineralization on enamel adjacent to orthodontic brackets, while the fluoride-containing bonding composite resin does not influence it. CLINICAL SIGNIFICANCE: Since high-fluoride dentifrice was able to reduce demineralization adjacent to brackets, it can be an option to caries management in orthodontics patients.

Oxidative stress resistance in a short-lived Neotropical annual killifish.

Oxidative stress plays an important role in the evolution of aging and life history. High investments in life-history traits and environmental conditions can be associated with increased oxidative stress and aging process. However, to date, most studies that investigated variations in oxidative status were performed with long-lived vertebrates. Studies with short-lived vertebrates in wild are nonexistent. Annual killifishes have the shortest lifespans among vertebrates and inhabit temporary ponds subject to large variations in environmental conditions. In this sense, we investigated whether the high investment in growth and reproduction in a short-lived vertebrate and the large variations in environment has any cost in susceptibility to oxidative stress. We assessed the seasonal variation and the environmental correlates of four different oxidative status markers (lipid peroxidation and activity of the antioxidant enzymes Superoxide Dismutase, Catalase and Glutathione S-Transferase) along the life cycle of wild individuals of the Neotropical annual fish Austrolebias minuano. Males showed reduction in all biomarkers (except proteins) along their life cycle, while females showed increased oxidative stress only in the growth period. In addition, we showed that water physicochemical parameters, habitat structure and presence of co-occurring killifish species influenced the seasonal variation of the biomarkers. A. minuano showed an efficient antioxidant system for most part of their life cycle (mainly in males), suggesting a well-developed oxidative stress regulation system. We also show that annual fish mortality (mainly in males) apparently is not related to oxidative stress. Thus, environmental factors should drive annual fish aging and mortality.