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1.
J Dairy Sci ; 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38788837

RESUMO

An economic simulation was carried out over 183 milk-producing countries to estimate the global economic impacts of 12 dairy cattle diseases and health conditions: mastitis (subclinical and clinical), lameness, paratuberculosis (Johne's disease), displaced abomasum, dystocia, metritis, milk fever, ovarian cysts, retained placenta, and ketosis (subclinical and clinical). Estimates of disease impacts on milk yield, fertility, and culling were collected from the literature, standardized, meta-analyzed using a variety of methods ranging from simple averaging to random-effects models, and adjusted for comorbidities to prevent overestimation. These comorbidity-adjusted disease impacts were then combined with a set of country-level lactational incidence and/or prevalence estimates, herd characteristics, and price estimates within a series of Monte Carlo simulations that estimated and valued the economic losses due to these diseases. It was estimated that total annual global losses are USD 65 billion (B). Subclinical ketosis, clinical mastitis, and subclinical mastitis were the costliest diseases modeled, resulting in mean annual global losses of approximately USD 18B, USD 13B, and USD 9B, respectively. Estimated global annual losses due to clinical ketosis, displaced abomasum, dystocia, lameness, metritis, milk fever, ovarian cysts, paratuberculosis, and retained placenta were estimated to be USD 0.2B, 0.6B, 0.6B, 6B, 5B, 0.6B, 4B, 4B, and 3B, respectively. Without adjustment for comorbidities, when statistical associations between diseases were disregarded, mean aggregate global losses would have been overestimated by 45%. Although annual losses were greatest in India (USD 12B), the USA (USD 8B), and China (USD 5B), depending on the measure of losses used (losses as a percent of GDP, losses per capita, losses as a percent of gross milk revenue), the relative economic burden of these dairy cattle diseases across countries varied markedly.

2.
Dig Dis Sci ; 69(5): 1778-1784, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38457115

RESUMO

BACKGROUND: Fecal microbiota transplants can be administered orally in encapsulated form or require invasive procedures to administer liquid formulations. There is a need for an oral liquid formulation of fecal microbiota for patients who are unable to swallow capsules, especially if they require multiple, repeated administrations. AIMS: These studies were conducted to develop a protocol to manufacture an organoleptically acceptable powdered fecal microbiota formulation that can be suspended in a liquid carrier and used for fecal microbiota transplantation. METHODS: Several processing steps were investigated, including extra washes of microbiota prior to lyophilization and an addition of a flavoring agent. The viability of bacteria in the transplant formulation was tested using live/dead microscopy staining and engraftment into antibiotic-treated mice. After development of a clinical protocol for suspension of the powdered microbiota, the new formulation was tested in three elderly patients with recurrent Clostridioides difficile infections and who have difficulties in swallowing capsules. Changes in the microbial community structure in one of the patients were characterized using 16S rRNA gene profiling and engraftment analysis. RESULTS: The processing steps used to produce an organoleptically acceptable suspension of powdered fecal microbiota did not result in loss of its viability. The powder could be easily suspended in a liquid carrier. The use of the new formulation was associated with abrogation of the cycle of C. difficile infection recurrences in the three patients. CONCLUSION: We developed a novel organoleptically acceptable liquid formulation of fecal microbiota that is suitable for use in clinical trials for patients with difficulties in swallowing capsules.


Assuntos
Transplante de Microbiota Fecal , Transplante de Microbiota Fecal/métodos , Humanos , Animais , Administração Oral , Infecções por Clostridium/terapia , Infecções por Clostridium/microbiologia , Camundongos , Idoso , Fezes/microbiologia , Clostridioides difficile/isolamento & purificação , Recidiva , Masculino , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Pós , Resultado do Tratamento , Idoso de 80 Anos ou mais
3.
Br J Math Stat Psychol ; 76(1): 1-19, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36081300

RESUMO

In many psychological studies, in particular those conducted by experience sampling, mental states are measured repeatedly for each participant. Such a design allows for regression models that separate between- from within-person, or trait-like from state-like, components of association between two variables. But these models are typically designed for continuous variables, whereas mental state variables are most often measured on an ordinal scale. In this paper we develop a model for disaggregating between- from within-person effects of one ordinal variable on another. As in standard ordinal regression, our model posits a continuous latent response whose value determines the observed response. We allow the latent response to depend nonlinearly on the trait and state variables, but impose a novel penalty that shrinks the fit towards a linear model on the latent scale. A simulation study shows that this penalization approach is effective at finding a middle ground between an overly restrictive linear model and an overfitted nonlinear model. The proposed method is illustrated with an application to data from the experience sampling study of Baumeister et al. (2020, Personality and Social Psychology Bulletin, 46, 1631).


Assuntos
Dinâmica não Linear , Humanos , Modelos Lineares , Simulação por Computador
4.
One Health ; 15: 100442, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36249991

RESUMO

Background: The Global Laboratory Leadership Programme (GLLP) has biosafety and biosecurity as one of its core competencies and advocates for a One Health approach involving all relevant sectors across the human-animal-environment interface to empower national laboratory systems and strengthen health security. Decentralization of SARS-CoV-2 testing in Liberia coupled with an increase in the number of COVID-19 infections among laboratory professionals raised biosafety concerns. In response, a set of trainings on laboratory biosafety was launched for lab personnel across the country under the framework of the GLLP. The goal was to deliver a comprehensive package for laboratory biosafety in the context of SARS-CoV-2 through active learning. Methods: Three one-day workshops were conducted between September and October 2020, training personnel from human, animal and environmental laboratories through a One Health approach. Concepts critical to laboratory biosafety were delivered in an interactive engagement format to ensure effective learning and retention of concepts. Pre- and post-training assessments were performed, and a paired t-test was used to assess knowledge gain. Results: Of the 67 participants, 64 were from the human health sector, one from veterinary sector and two from environmental health sector. The average pre-test score was 41%. The main gaps identified were failure to acknowledge surgical antisepsis as a form of hand hygiene and recognition of PPE as the best risk control measure. The average post-test score was 75.5%. The mean difference of pre-test and post-test scores was statistically significant (p-value <0.001). Participants indicated satisfaction with the workshop content, mode of delivery and trainers' proficiency. Conclusions: The workshops were impactful as evidenced by significant improvement (34.5%) in the post-test scores and positive participant feedback. Repeated refresher trainings are vital to addressing the gaps, ensuring compliance, and promoting biosafety culture. GLLP's approach to cultivating multisectoral national laboratory leaders ready to take responsibility and ownership for capacity building provides a sustainable solution for attaining strong national laboratory systems better prepared for health emergencies and pandemics like COVID-19.

5.
Clin Nutr ; 41(6): 1153-1162, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35500315

RESUMO

BACKGROUND: Hydrogen sulfide (H2S) is a toxic end-product of microbial fermentation produced in the colon that may play a role in the pathogenesis of several diseases, including ulcerative colitis and colon cancer. However, the effect of diet interventions on intestinal burden of H2S gas exposure remains poorly understood. OBJECTIVE: Determine the effect of short-term (1-week) plant- and animal-based eating patterns on ex vivo fecal H2S production in healthy human volunteers. METHODS: The study design was an open-label, cross-over diet study and diets were self-administered. Each participant consumed two interventional diets: 1) an animal-based, low fiber (i.e. western) diet and 2) a plant-based, high fiber diet, separated by a two-week washout period. Participants collected full stool samples at the end of each week, which were processed within 2 h of collection to capture H2S production. Microfluidic qPCR (MFQPCR) was used to simultaneously quantify multiple taxonomic and functional groups involved in sulfate reduction and the fecal microbiota was characterized through high-throughput DNA sequencing. RESULTS: Median H2S production was higher following the animal-based diet compared to the plant-based diet (p = 0.02; median difference 29 ppm/g, 95% CI 16-97). However, there was substantial individual variability and 2 of 11 individuals (18%) produced more H2S on the plant-based diet. Using the top and bottom quartiles of H2S percent change between animal- and plant-based diet weeks to define responders and non-responders, significant taxonomic differences were observed between the responder and non-responder cohorts. CONCLUSIONS: Here we report that substrate changes associated with a 1-week plant-based diet intervention resulted in lower ex vivo H2S production compared to a 1-week animal-based diet intervention in most healthy individuals. However, H2S responsiveness to diet was not uniform across the entire cohort, and potential H2S production enterotypes were characterized that may predict individualized H2S responsiveness to diet.


Assuntos
Sulfeto de Hidrogênio , Animais , Estudos Cross-Over , Dieta , Dieta Vegetariana , Fibras na Dieta , Humanos , Hidrogênio , Sulfeto de Hidrogênio/análise
6.
Eur J Pharmacol ; 927: 174975, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35469837

RESUMO

The growing burden of myocardial infarction (MI) becomes a major global health issue that is accountable for considerable mortality worldwide. Hence, it is obligatory to develop a new treatment for MI having lesser side effects. Cardiac hypertrophy, oxidative stress, and inflammatory pathways play crucial roles in the pathogenesis of MI. This investigation established the anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects of valencene. Rats were induced MI by isoproterenol (100 mg/kg body weight) and then treated with valencene and cardiac sensitive markers, cardiac hypertrophy, oxidative stress, markers of inflammation, nuclear factor- κB inflammatory pathway, and myocardial infarct size was estimated/determined. The serum cardiac diagnostic markers, cardiac hypertrophy, conjugated dienes, markers of inflammation, pro-inflammatory cytokines, and myocardial infarct size were significantly (P < 0.05) increased by isoproterenol. Further, antioxidant enzymes and anti-inflammatory cytokine gene were significantly (P < 0.05) decreased in the heart. The 2, 3, 5-triphenyl tetrazolium chloride dye staining revealed a larger infarct size. Moreover, histological results of myocardial infarcted rat's cardiac tissue revealed separation of cardiac muscle fibers, necrosis, and inflammatory cells. Post-treatment with valencene (12 mg/kg body weight) orally, daily, for two weeks to isoproterenol-induced myocardial infarcted rats reversed all above said structural, biochemical, molecular, and histological parameters investigated, by its anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects. Thus, valencene is a potential candidate for inhibiting cardiac hypertrophy, oxidative stress, nuclear factor- κB inflammatory pathway, and myocardial infarct size and exhibited cardioprotection in MI.


Assuntos
Antioxidantes , Infarto do Miocárdio , Animais , Anti-Inflamatórios , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Peso Corporal , Cardiomegalia/induzido quimicamente , Cardiomegalia/tratamento farmacológico , Cardiomegalia/metabolismo , Inflamação/metabolismo , Isoproterenol/farmacologia , Infarto do Miocárdio/induzido quimicamente , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , NF-kappa B/metabolismo , Estresse Oxidativo , Ratos , Ratos Wistar , Sesquiterpenos
7.
Infect Dis Model ; 7(1): 252-261, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35198841

RESUMO

In this paper, we present the impact of migration on the spread of HIV and AIDS cases. A simple model for HIV and AIDS that incorporates migration and addresses its contributions to the spread of HIV and AIDS cases was constructed. The model was calibrated to HIV and AIDS incidence data from Malaysia. We explore the use of Markov chain Monte Carlo (MCMC) simulation method to estimate uncertainty in all the unknown parameters incorporated in our proposed model. Among the migrant population, 1.5572e-01 were susceptible to HIV transmission, which constituted 67,801 migrants. A proportion of migrants, 6.3773e-04, were estimated to be HIV infected, constituting 278 migrants. There were 72 (per 10,000) migrants estimated to have had AIDS, representing a proportion of 1.6611e-08. The result suggests that the disease-free steady state was unstable since the estimated basic reproduction number R 0 was 2.0906 and 2.3322 for the models without and with migration, respectively. This is not a good indicator from the public health point of view, as the aim is to stabilize the epidemic at the disease-free equilibrium. The advantage of introduction of migration to the simple model validated the true R 0 and the transmission rate ß associated with HIV and AIDS epidemic disease in Malaysia. It also indicates an approximately 12 percentage points increase in the rate of HIV infection with migration.

8.
Front Microbiol ; 12: 807068, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34966379

RESUMO

[This corrects the article DOI: 10.3389/fmicb.2021.706683.].

9.
Front Microbiol ; 12: 706683, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539605

RESUMO

Sea lamprey (SL; Petromyzon marinus), one of the oldest living vertebrates, have a complex metamorphic life cycle. Following hatching, SL transition into a microphagous, sediment burrowing larval stage, and after 2-10+ years, the larvae undergo a dramatic metamorphosis, transforming into parasitic juveniles that feed on blood and bodily fluids of fishes; adult lamprey cease feeding, spawn, and die. Since gut microbiota are critical for the overall health of all animals, we examined the microbiota associated with SLs in each life history stage. We show that there were significant differences in the gut bacterial communities associated with the larval, parasitic juvenile, and adult life stages. The transition from larval to the parasitic juvenile stage was marked with a significant shift in bacterial community structure and reduction in alpha diversity. The most abundant SL-associated phyla were Proteobacteria, Fusobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, and Firmicutes, with their relative abundances varying among the stages. Moreover, while larval SL were enriched with unclassified Fusobacteriaceae, unclassified Verrucomicrobiales and Cetobacterium, members of the genera with fastidious nutritional requirements, such as Streptococcus, Haemophilus, Cutibacterium, Veillonella, and Massilia, were three to four orders of magnitude greater in juveniles than in larvae. In contrast, adult SLs were enriched with Aeromonas, Iodobacter, Shewanella, and Flavobacterium. Collectively, our findings show that bacterial communities in the SL gut are dramatically different among its life stages. Understanding how these communities change over time within and among SL life stages may shed more light on the role that these gut microbes play in host growth and fitness.

10.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-21257612

RESUMO

The coronavirus outbreak continues to pose a significant challenge to human lives globally. Many efforts have been made to develop vaccines to combat this virus. However, with the arrival of the COVID-19 vaccine, there is hesitancy and a mixed reaction toward getting the vaccine. We develop a mathematical model to analyze and investigate the impacts of education on individuals hesitant to get vaccinated. The findings indicate that vaccine education can substantially minimize the daily cumulative cases and deaths of COVID-19 in the United States. The results also show that vaccine education significantly increases the number of willing susceptible individuals, and with a high vaccination rate and vaccine effectiveness, the outbreak can be controlled in the US.

11.
Microb Ecol ; 81(4): 1042-1053, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33244619

RESUMO

Host-associated microbiota play a critical role in host fitness by providing nutrition, enhancing digestion capabilities, and by providing protection from pathogens. Here, we investigated the effects of two environmental stressors, temperature, and salinity, on the microbiota associated with zebra mussels (ZMs), a highly invasive bivalve in North America. To examine this in detail, lake-collected ZMs were acclimated to laboratory conditions, and subjected to temperature and salinity stress conditions. The impact of these stressors on the diversity, composition, and dynamics of ZM-associated microbiota were assessed by using amplicon- and shotgun-based sequencing, and qPCR-based approaches. Elevated temperature was found to be the primary driver of ZM mortality, although salinity alone also increased its likelihood. Stressor-induced ZM mortality, which ranged between 53 and 100%, was concomitant with significant increases in the relative abundance of several genera of putative opportunistic pathogens including Aeromonas. These genera were only present in low relative abundance in ZMs obtained from the control tank with 0% mortality. Shotgun sequencing and qPCR analyses indicated that the relative and absolute abundances of pathogenic Aeromonas species (particularly A. veronii) were significantly greater in temperature-induced dead ZMs. Taken together, our results show that environmental stress, especially elevated temperature (> 25 °C), is associated with the rapid mortality of ZMs as well as the proliferation of putative opportunistic bacterial pathogens.


Assuntos
Bivalves , Dreissena , Microbiota , Animais , Lagos , Temperatura
12.
Sci Total Environ ; 760: 144092, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33341626

RESUMO

The Amazon rainforest is the world's largest tropical forest, and this biome may be a significant contributor to primary biological aerosol (PBA) emissions on a global scale. These aerosols also play a pivotal role in modulating ecosystem dynamics, dispersing biological material over geographic barriers and influencing climate through radiation absorption, light scattering, or acting as cloud condensation nuclei. Despite their importance, there are limited studies investigating the effect of environmental variables on the bioaerosol composition in the Amazon rainforest. Here we present a 16S rRNA gene-based amplicon sequencing approach to investigate the bacterial microbiome in aerosols of the Amazon rainforest during distinct seasons and at different heights above the ground. Our data revealed that seasonal changes in temperature, relative humidity, and precipitation are the primary drivers of compositional changes in the Amazon rainforest aerosol microbiome. Interestingly, no significant differences were observed in the bacterial community composition of aerosols collected at ground and canopy levels. The core airborne bacterial families present in Amazon aerosol were Enterobacteriaceae, Beijerinckiaceae, Polyangiaceae, Bacillaceae and Ktedonobacteraceae. By correlating the bacterial taxa identified in the aerosol with literature data, we speculate that the phyllosphere may be one possible source of airborne bacteria in the Amazon rainforest. Results of this study indicate that the aerosol microbiota of the Amazon Rainforest are fairly diverse and principally impacted by seasonal changes in temperature and humidity.


Assuntos
Microbiota , Floresta Úmida , Aerossóis , Florestas , Humanos , RNA Ribossômico 16S/genética
13.
Dig Dis Sci ; 66(11): 3822-3830, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33247793

RESUMO

BACKGROUND: Intestinal methane (CH4) gas production has been associated with a number of clinical conditions and may have important metabolic and physiological effects. AIMS: In this study, taxonomic and functional gene analyses and in vitro CH4 gas measurements were used to determine if molecular markers can potentially serve as clinical tests for colonic CH4 production. METHODS: We performed a cross-sectional study involving full stool samples collected from 33 healthy individuals. In vitro CH4 gas measurements were obtained after 2-h incubation of stool samples and used to characterize samples as CH4 positive (CH4+) and CH4 negative (CH4-; n = 10 and 23, respectively). Next, we characterized the fecal microbiota through high-throughput DNA sequencing with a particular emphasis on archaeal phylum Euryarchaeota. Finally, qPCR analyses, targeting the mcrA gene, were done to determine the ability to differentiate CH4+ versus CH4- samples and to delineate major methanogen species associated with CH4 production. RESULTS: Methanobrevibacter was found to be the most abundant methane producer and its relative abundance provides a clear distinction between CH4+ versus CH4- samples. Its sequencing-based relative abundance detection threshold for CH4 production was calculated to be 0.097%. The qPCR-based detection threshold separating CH4+ versus CH4- samples, based on mcrA gene copies, was 5.2 × 105 copies/g. CONCLUSION: Given the decreased time-burden placed on patients, a qPCR-based test on a fecal sample can become a valuable tool in clinical assessment of CH4 producing status.


Assuntos
Bactérias/metabolismo , Euryarchaeota/isolamento & purificação , Fezes/microbiologia , Metano/metabolismo , Methanobacteriales/isolamento & purificação , Bactérias/classificação , DNA Arqueal/genética , DNA Bacteriano/genética , Euryarchaeota/genética , Humanos , Methanobacteriales/genética , Especificidade da Espécie
14.
Infect Dis Model ; 5: 755-765, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073067

RESUMO

Malaysia is faced with a high HIV/AIDS burden that poses a public health threat. We constructed and applied a compartmental model to understand the spread and control of HIV/AIDS in Malaysia. A simple model for HIV and AIDS disease that incorporates condom and uncontaminated needle-syringes interventions and addresses the relative impact of given treatment therapy for infected HIV newborns on reducing HIV and AIDS incidence is presented. We demonstrated how treatment therapy for new-born babies and the use of condoms or uncontaminated needle-syringes impact the dynamics of HIV in Malaysia. The model was calibrated to HIV and AIDS incidence data from Malaysia from 1986 to 2011. The epidemiological parameters are estimated using Bayesian inference via Markov chain Monte Carlo simulation method. The reproduction number optimal for control of the HIV/AIDS disease obtained suggests that the disease-free equilibrium was unstable during the 25 years. However, the results indicated that the use of condoms and uncontaminated needle-syringes are pivotal intervention control strategies; a comprehensive adoption of the intervention may help stop the spread of HIV disease. Treatment therapy for newborn babies is also of high value; it reduces the epidemic peak. The combined effect of condom use or uncontaminated needle-syringe is more pronounced in controlling the spread of HIV/AIDS.

15.
J Microbiol Methods ; 177: 106050, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32891632

RESUMO

The development of Microbial Source Tracking (MST) technologies was borne out of necessity. This was largely due to the: 1) inadequacies of the fecal indicator bacterial paradigm, 2) fact that many fecal bacteria can survive and often grow in the environment, 3) inability of traditional microbiological methods to attribute source, 4) lack of correspondence between numbers of fecal indicator bacteria in waterways and many human pathogens, and 5) source allocation requirements and load determinations needed for total maximum daily loads. The MST tools have changed over time, evolving from culture-dependent to culture-independent molecular analyses. More recently, MST tools based on microbial community analyses, mainly DNA sequencing-based approaches, have been developed in an attempt to overcome some of these issues. These approaches generate large data sets and require the use of sophisticated machine learning algorithms to allocate potential host sources to contaminated waterways. In this review we discuss the origins and needs for community-based MST methods, as well as elaborate on the Bayesian algorithm-based program SourceTracker, which is increasingly being used for the determination of sources of fecal contamination of waterways.


Assuntos
Monitoramento Ambiental/métodos , Aprendizado de Máquina , Microbiota , Microbiologia da Água , Algoritmos , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Técnicas Bacteriológicas/métodos , Teorema de Bayes , Fezes/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Microbiota/genética , Poluição da Água/análise
16.
J Biochem Mol Toxicol ; 34(10): e22556, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32627257

RESUMO

Myocardial infarction (MI) is a life-threatening disease. In this study, we examined the anti-mitochondrial damaging effects of sinapic acid (SA) in isoproterenol (ISO)-induced myocardial infarcted rats. Myocardial infarcted rats were prepared by injecting ISO (100 mg/kg body weight) on the 9th and 10th day. Rats were pretreated and cotreated with SA (12 mg/kg body weight) orally, daily for 10 days. A considerable increase in serum lactate dehydrogenase, creatine kinase, myoglobin, and cardiac troponin-T was noticed in the ISO-induced rats. ISO also significantly amplified lipid peroxidation and calcium ions, and depleted the antioxidant system and mitochondrial enzymes in rat's heart mitochondria. SA treatment improved the distorted above- mentioned biochemical parameters in ISO-treated rats with its anti-mitochondrial damaging effects. This ultrastructural study on heart mitochondria and in vitro studies also confirmed the effects of SA. The current findings are suggestive of SA's cardioprotective effects.


Assuntos
Agonistas Adrenérgicos beta/toxicidade , Cardiotônicos/farmacologia , Ácidos Cumáricos/farmacologia , Isoproterenol/toxicidade , Mitocôndrias Cardíacas/efeitos dos fármacos , Infarto do Miocárdio/patologia , Animais , Biomarcadores/sangue , Masculino , Mitocôndrias Cardíacas/ultraestrutura , Infarto do Miocárdio/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar
17.
Ecotoxicol Environ Saf ; 195: 110458, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32193021

RESUMO

Arsenic (As) is a pollutant of major concern worldwide, posing as a threat to both human health and the environment. Phytoremediation has been proposed as a viable mechanism to remediate As-contaminated soil environments. Pot experiments were performed to evaluate the phytoextraction efficiency of As by Pteris vittata, a known As hyperaccumulating fern, from soil amended with different concentrations of arsenate [As(V)] and arsenite [As(III)], the more common, inorganic As forms in soil. The greatest accumulation of As (13.3 ± 0.36 g/kg Dwt) was found in fronds of plants grown in soil spiked with 1.0 g As(V)/kg. The maximum As-bioaccumulation factor (27.3 ± 1.9) was achieved by plants grown in soil amended with 0.05 g As(V)/kg. A total of 864 bacterial cultures were isolated and examined for their ability to enhance phytoremediation of As-contaminated soils. Traits examined included tolerance to As (III and V), production of siderophores, and/or ability to solubilize calcium phosphate and indole acetic acid (IAA) production. A culture-based survey shows greater numbers of viable and As-resistant bacteria were found in the rhizosphere of As-grown plants compared to bulk and unplanted soils. The percentage of bacteria resistant to As(V) was greater (P < 0.0001) than those resistant to As(III) in culture medium containing 0.5, 1, 1.5, and 2 g As/L. Higher (P < 0.0001) percentages of siderophore producing (77%) and phosphate solubilizing (61%) bacteria were observed among cultures isolated from unplanted soil. About 5% (44 of 864) of the isolates were highly resistant to both As (III) and As (V) (2 g/L), and were examined for their As-transformation ability and IAA production. A great proportion of the isolates produced IAA (82%) and promoted As (V)-reduction (95%) or As(III)-oxidation (73%), and 71% exhibited dual capacity for both As(V) reduction and As(III) oxidation. Phylogenetic analysis indicated that 67, 23, and 10% of these isolates belonged to Proteobacteria, Actinobacteria, and Firmicutes, respectively. Analysis of the 16S rRNA gene sequences confirmed that these isolates were closely related to 12 genera and 25 species of bacteria and were dominated by members of the genus Pseudomonas (39%). These results show that these isolates could potentially be developed as inocula for enhancing plant uptake during large scale phytoremediation of As-impacted soils.


Assuntos
Arseniatos/farmacocinética , Arsenitos/farmacocinética , Pteris/metabolismo , Microbiologia do Solo , Poluentes do Solo/farmacocinética , Arseniatos/toxicidade , Arsenitos/toxicidade , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodegradação Ambiental , Ácidos Indolacéticos/metabolismo , Rizosfera , Sideróforos/metabolismo , Poluentes do Solo/toxicidade
18.
Appl Microbiol Biotechnol ; 104(10): 4563-4575, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32219463

RESUMO

Buildup of volatile fatty acids (VFAs) in anaerobic digesters (ADs) often results in acidification and process failure. Understanding the dynamics of microbial communities involved in VFA degradation under stable and overload conditions may help optimize anaerobic digestion processes. In this study, five triplicate mesophilic completely mixed AD sets were operated at different organic loading rates (OLRs; 1-6 g chemical oxygen demand [COD] LR-1day-1), and changes in the composition and abundance of VFA-degrading microbial communities were monitored using amplicon sequencing and taxon-specific quantitative PCRs, respectively. AD sets operated at OLRs of 1-4 g COD LR-1day-1 were functionally stable throughout the operational period (120 days) whereas process instability (characterized by VFA buildup, pH decline, and decreased methane production rate) occurred in digesters operated at ≥ 5 g COD LR-1day-1. Though microbial taxa involved in propionate (Syntrophobacter and Pelotomaculum) and butyrate (Syntrophomonas) degradation were detected across all ADs, their abundance decreased with increasing OLR. The overload conditions also inhibited the proliferation of the acetoclastic methanogen, Methanosaeta, and caused a microbial community shift to acetate oxidizers (Tepidanaerobacter acetatoxydans) and hydrogenotrophic methanogens (Methanoculleus). This study's results highlight the importance of operating ADs with conditions that promote the maintenance of microbial communities involved in VFA degradation.


Assuntos
Bactérias Anaeróbias/metabolismo , Reatores Biológicos/microbiologia , Ácidos Graxos Voláteis/metabolismo , Microbiota , Anaerobiose , Firmicutes/metabolismo , Metano/metabolismo , Methanomicrobiaceae/metabolismo , Esgotos
19.
J Conserv Dent ; 23(4): 341-347, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33623233

RESUMO

OBJECTIVES: The primary objective of this study was to investigate the effectiveness in reducing dentin hypersensitivity in noncarious cervical lesions (NCCLs) by home-based desensitizing toothpaste (TP), in-office Gluma desensitizer application, and resin-modified glass-ionomer cement (RMGIC) restoration. The secondary objective was to evaluate the long-term outcome of the glass-ionomer cement restoration following the application of bioactive glass-containing desensitizer TP. MATERIALS AND METHODS: A total of 73 patients or 151 teeth were included in the study and randomly allotted to one of the four different treatment groups. Pre- and postoperative symptom and air-blast/tactile sensitivity scores were recorded for statistical analysis. Postoperative sensitivity was analyzed at 1, 4, and 12 weeks after treatment. Nonparametric statistical tests were employed. RESULTS: Kruskal-Wallis test noted a significant reduction in postoperative sensitivity at all time periods with the RMGIC group compared to other treatment options. Significantly higher patient dropout was observed in desensitizing TP regimen. CONCLUSIONS: This interim 12-week report on dentin hypersensitivity management of NCCLs concludes that resin-modified glass-ionomer restoration was able to achieve a significant instant reduction in sensitivity and patient satisfaction compared to other noninvasive at-home and in-office procedures. CLINICAL RELEVANCE: This interim 12-week report on dentin hypersensitivity management of noncarious cervical lesions concludes that resin-modified glass-ionomer restoration was able to achieve a significant reduction in sensitivity, and patient satisfaction was higher compared to other noninvasive at-home and in-office procedures.

20.
Sci Total Environ ; 703: 134915, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767301

RESUMO

Zebra mussels (Dreissena polymorpha) are invasive, filter-feeding, bivalves that have disrupted the ecology of thousands of freshwater biomes across North America. Due to their efficient filter-feeding activity, zebra mussels (ZMs) and other bivalves are extensively used to detect chemical contamination in waterways. In this study, we evaluated whether water and sediment serve as major sources of ZM tissue-associated microbiota, and whether ZMs serve as a reservoir for potentially pathogenic microbes in aquatic systems. High-throughput DNA sequencing of 16S rRNA gene was done to characterize the microbial community structure in 472 environmental samples, comprising ZMs, sediment, and the water column, collected from 15 lakes during the summer and fall months. Sequence analyses, done using the SourceTracker program, predicted that water and sediment contributed up to 91 and 86%, respectively, to the structure of microbiota within ZMs, and that mussels from the same site showed nearly identical source microbiota profiles. The relatively high local source contribution suggests that the microbiota in ZM tissue has the potential to reflect biological contamination and this phenomenon can be used to monitor microbial water quality. A preferential enrichment of several taxa was also observed in ZM tissues, including potential pathogenic groups such as Aeromonas, Enterobacteriaceae, and Pseudomonas. Taken together, our results contribute to an improved understanding of ZMs as a sentinel species in aquatic habitats and its potential impact to water quality management.


Assuntos
Bivalves , Animais , Sedimentos Geológicos , América do Norte , RNA Ribossômico 16S , Água
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