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1.
Vocat Learn ; 16(3): 511-532, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38028234

RESUMO

New vocational education and training (VET) teachers in Quebec (Canada), as in other countries (e.g., France, the Netherlands, Norway, Sweden, Switzerland, the United States), face specific challenges and experience an atypical process of entry into the teaching profession. In addition to the known professional induction challenges, which requires numerous adjustments in terms of organizational integration and socialization as well as on a personal level, new VET teachers also experience a major professional and identity transition: they shift from experts in their field to novices in the teaching field. Moreover, as they are not generally trained in pedagogy, new teachers must enroll in a mandatory teaching bachelor's program once they are fully in charge of a class and its educational responsibilities. This complex process calls for a closer look at ways to facilitate their induction experience. Specifically, because it is closely related to motivation, engagement, and performance, this study focuses on their perceived self-efficacy as teachers. This study focused on 21 new VET teachers in the francophone province of Quebec, Canada, and aim to identify different strategies through which they succeeded in developing and maintaining their self-efficacy: strategies related to 1) the work of teaching, 2) mobilization of resources, 3) professional development, and 4) attitudes and well-being at work. These strategies allow us to gain a deeper understanding of previously unexplored aspects of the reality of these teachers, and to propose avenues for the development of interventions targeting their needs.

2.
Thromb J ; 20(1): 38, 2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35787808

RESUMO

BACKGROUND: ChAdOx1 nCoV-19 (AstraZeneca) and Ad26COV2.S (Johnson & Johnson/Janssen) adenoviral vector vaccines have been associated with vaccine-induced immune thrombotic thrombocytopenia (VITT). Arterial thrombosis and acute limb ischemia have been described in a minority of patients with VITT. These patients usually need a revascularization, but they potentially are at a higher risk of complications. Optimal perioperative care of patients undergoing vascular surgery in acute VITT is unknown and important considerations in such context need to be described. CASES PRESENTATIONS: We report 2 cases of VITT presenting with acute limb ischemia who needed vascular surgery and we describe the multidisciplinary team decisions for specific treatment surrounding the interventions. Both patients' platelet counts initially increased after either intravenous immune globulin (IVIG) or therapeutic plasma exchange (TPE). None received platelet transfusion. They both received argatroban as an alternative to heparin for their surgery. Despite persistent positivity of anti-platelet factor 4 (PF4) antibodies and serotonin-release assay with added PF4 (PF4-SRA) in both patients, only one received a repeated dose of IVIG before the intervention. Per- and post-operative courses were both unremarkable. CONCLUSION: In spite of persistent anti-PF4 and PF4-SRA positivity in the setting of VITT, after platelet count improvement using either IVIG or TPE, vascular interventions using argatroban can show favorable courses. Use of repeated IVIG or TPE before such interventions still needs to be defined.

3.
Br J Hosp Med (Lond) ; 83(5): 1-8, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35653319

RESUMO

Faculty development is key to ensuring quality clinical teaching, but standardising teaching practices in multiple settings is a challenge. This article presents an example of a 3-year faculty development programme for teaching clinical reasoning skills, implemented by the Faculty of Medicine and Health Sciences, University of Sherbrooke, Quebec, Canada for its faculty members at multiple teaching sites. A follow-up study 1-5 months after the final workshop, using a self-assessment questionnaire, indicates that almost half of the participants transferred some of their newly acquired knowledge into their teaching practices. This article discusses factors to consider when developing a faculty development culture, at both a programme and faculty level, to support quality teaching and learning.


Assuntos
Docentes de Medicina , Aprendizagem , Seguimentos , Humanos , Autoavaliação (Psicologia) , Inquéritos e Questionários
4.
MAbs ; 13(1): 1999194, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34806527

RESUMO

The architectural complexity and heterogeneity of the tumor microenvironment (TME) remains a substantial obstacle in the successful treatment of cancer. Hypoxia, caused by insufficient oxygen supply, and acidosis, resulting from the expulsion of acidic metabolites, are prominent features of the TME. To mitigate the consequences of the hostile TME, cancer cells metabolically rewire themselves and express a series of specific transporters and enzymes instrumental to this adaptation. One of these proteins is carbonic anhydrase (CA)IX, a zinc-containing extracellular membrane bound enzyme that has been shown to play a critical role in the maintenance of a neutral intracellular pH (pHi), allowing tumor cells to survive and thrive in these harsh conditions. Although CAIX has been considered a promising cancer target, only two antibody-based therapeutics have been clinically tested so far. To fill this gap, we generated a series of novel monoclonal antibodies (mAbs) that specifically recognize the extracellular domain (ECD) of human CAIX. Here we describe the biophysical and functional properties of a set of antibodies against the CAIX ECD domain and their applicability as: 1) suitable for development as an antibody-drug-conjugate, 2) an inhibitor of CAIX enzyme activity, or 3) an imaging/detection antibody. The results presented here demonstrate the potential of these specific hCAIX mAbs for further development as novel cancer therapeutic and/or diagnostic tools.


Assuntos
Antineoplásicos Imunológicos , Anidrases Carbônicas , Anticorpos Monoclonais/farmacologia , Antígenos de Neoplasias , Biomarcadores Tumorais , Anidrases Carbônicas/química , Anidrases Carbônicas/metabolismo , Linhagem Celular Tumoral , Humanos , Concentração de Íons de Hidrogênio
6.
Appl Environ Microbiol ; 87(8)2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33514521

RESUMO

Pigs are major reservoirs of resistant Enterobacteriaceae that can reach humans through consumption of contaminated meat or vegetables grown in manure-fertilized soil. Samples were collected from sows during lactation and their piglets at five time points spanning the production cycle. Cefotaxime-resistant bacteria were quantified and isolated from feed, feces, manures and carcasses of pigs reared with penicillin-using or antibiotic-free husbandries. The isolates were characterized by antibiotic susceptibility testing, whole genome sequencing and conjugation assays. The extended spectrum ß-lactamase (ESBL) phenotype was more frequent in isolates originating from antibiotic-free animals, while the bacteria isolated from penicillin-using animals were on average resistant to a greater number of antibiotics. The ESBL-encoding genes identified were bla CTX-M-1, bla CTX-M-15 and bla CMY-2 and they co-localised on plasmids with various genes encoding resistance to ß-lactams, co-trimoxazole, phenicols and tetracycline, all antibiotics used in pig production. Groups of genes conferring the observed resistance and the mobile elements disseminating multidrug resistance were determined. The observed resistance to ß-lactams was mainly due to the complementary actions of penicillin-binding proteins, an efflux pump and ß-lactamases. Most resistance determinants were shared by animals raised with or without antimicrobials. This suggests a key contribution of indigenous enterobacteria maternally transmitted along the sow lineage, regardless of antimicrobial use. It is unclear if the antimicrobial resistance observed in the enterobacteria populations of the commercial pig herds studied were present before the use of antibiotics, or the extent to which historical antimicrobial use exerted a selective pressure defining the resistant bacterial populations in farms using penicillin prophylaxis.Importance: Antimicrobial resistance is a global threat that needs to be fought on numerous fronts along the One Health continuum. Vast quantities of antimicrobials are used in agriculture to ensure animal welfare and productivity, and are arguably a driving force for the persistence of environmental and food-borne resistant bacteria. This study evaluated the impact of conventional, organic and other antibiotic-free husbandry practices on the frequency and nature of antimicrobial resistance genes and multidrug resistant enterobacteria. It provides knowledge about the relative contribution of specific resistance determinants to observed antibiotic resistance. It also showed the clear co-selection of genes coding for extended-spectrum beta-lactamases and genes coding for the resistance to antibiotics commonly used for prophylaxis or in curative treatments in pig operations.

7.
J Interpers Violence ; 36(11-12): 5501-5529, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-30317908

RESUMO

Life satisfaction in adolescence has been shown to protect against numerous negative outcomes (e.g., substance use, sexual risk-taking), but limited work has directly explored the relationship between life satisfaction and youth violence and offending. As such, we conducted a prospective assessment to explore this relationship among community (n = 334) and at-risk youth (n = 99). Findings suggest life satisfaction is significantly associated with decreased offending and violence within both samples and adds incremental value above established risk factors in predicting violent and total offending among community youth. Furthermore, moderation analyses indicate that the protective value of life satisfaction is greater for youth with high callous-unemotional traits. Mediation analyses suggest that youth who are unsatisfied with their lives may seek out substance use, in turn elevating risk of offending. Together, these findings indicate that efforts to improve overall life satisfaction may help prevent adolescent offending. However, future research is needed.


Assuntos
Delinquência Juvenil , Satisfação Pessoal , Adolescente , Agressão , Humanos , Estudos Prospectivos , Violência
9.
Br J Hosp Med (Lond) ; 81(3): 1-8, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32239995

RESUMO

Clinical reasoning is an essential part of medical practice and therefore should be an important part of clinical teaching. However, it has been and is still a challenge for clinical teachers to support learners in the development of their clinical reasoning skills. As learners progress in clerkship, so do their learning needs. As a result, teachers need multiple tools to foster the development of clinical reasoning and should know when and why to use them. This article presents tools gathered as part of a clinical teacher's toolbox aimed at coaching learners towards the next step in their clinical reasoning development as well as helping teachers diagnose clinical reasoning difficulties and meet the diverse learning needs of their learners. The article focuses on three tools that were developed by faculty at the University of Sherbrooke Faculty of Medicine and Health Sciences: the iSNAPPS-OMP Technique, the Anticipatory Supervision Technique and the Clinical Sudoku or table of discriminating clues. This article uses the term 'tools' as a generic expression to signify 'items in a toolbox'. It includes all kinds of resources (techniques, strategies, models) that were gathered to help clinical teachers with the teaching of clinical reasoning.


Assuntos
Estágio Clínico/organização & administração , Raciocínio Clínico , Docentes de Medicina/organização & administração , Ensino/organização & administração , Competência Clínica , Humanos , Aprendizagem , Resolução de Problemas
10.
Sci Total Environ ; 659: 640-648, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31096393

RESUMO

Animal manures are a valued source of nutrients for crop production. They frequently do, however, contain zoonotic pathogens including a wide range of viruses. Ideally, manures would be treated prior to land application, reducing the burden of zoonotic viruses, and thus the potential for transmission to adjacent water resources or crops intended for human or animal consumption. In the present study, manure was obtained from four dairy and three swine farms. The manure was incubated anaerobically in the laboratory for 28 weeks at temperatures ranging from 4 to 25 °C, and multiple physical and chemical parameters were monitored. The abundance of various DNA and RNA viruses was measured throughout the incubation by amplifying virus-specific gene targets. A combination of statistical analyses were applied to identify whether the viruses are significantly impacted by temperature transition or affected by other abiotic factors. Temperature had no effect on the persistence of any of the viruses studied. An increase in pH of the manures during the incubation was significantly (P < 0.05) associated with decreased persistence, suggesting that pH manipulation during storage could reduce the abundance of viruses.


Assuntos
Esterco/virologia , Fenômenos Fisiológicos Virais , Animais , Bovinos , Feminino , Concentração de Íons de Hidrogênio , Esterco/análise , Sus scrofa , Temperatura
11.
J Abnorm Child Psychol ; 44(8): 1599-1612, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-26830294

RESUMO

The Antisocial Process Screening Device (APSD) is a well-supported tool for assessing psychopathic features in youth. However, most research with the APSD has been derived from clinical and forensic samples comprised mainly of male Caucasian and African American adolescents. In this prospective study, the incremental and predictive validity of the self-report APSD for violent and non-violent offending was examined in an ethnically diverse community sample of male and female youth (N = 335) aged 12 to 14. High-school students from a moderate sized city in Western Canada completed the self-report APSD and then completed the Self-Report of Offending 6 months later. Receiver Operating Characteristics analysis indicated that APSD total and subscale scores were predictive of violent and non-violent offending at 6-month follow-up with moderate to large effect sizes. In addition, total scores on the APSD added incremental predictive utility above and beyond traditional criminogenic predictors of youth offending (i.e., prior offending, delinquent peer affiliation, poor school achievement, substance use, low parental monitoring). Although sex differences emerged in the predictive utility of the Impulsivity subscale of the APSD vis-à-vis violent offending, sex did not moderate the relationship between APSD total, Narcissism, or Callous/Unemotional scores and offending. In addition, the predictive utility of the APSD did not vary as a function of the youth's ethnic background. These findings suggest that: (1) the self-report APSD may have utility for risk or threat assessment with normative school populations, (2) APSD findings from higher risk samples generalize to a lower risk sample of high-school youth, and (3) predictive utility of APSD total scores do not differ across male and female Caucasian and ethnic minority youth.


Assuntos
Transtorno da Personalidade Antissocial/diagnóstico , Grupos Minoritários/psicologia , Escalas de Graduação Psiquiátrica , Adolescente , Negro ou Afro-Americano/psicologia , Transtorno da Personalidade Antissocial/psicologia , Criança , Feminino , Humanos , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes , População Branca/psicologia
12.
Syst Appl Microbiol ; 38(1): 56-66, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25511087

RESUMO

In order to develop approaches for reducing the carbon footprint of the swine and dairy industries, it is important first to identify the methanogenic communities that drive methane emissions from stored manure. In this study, the metabolically active methanogens in substrate-starved manure samples taken from two dairy and one swine manure storage tanks were identified using [(13)C]-acetate and DNA stable-isotope probing (DNA-SIP). Molecular analysis of recovered genomic [(13)C]-DNA revealed that two distinct clusters of unclassified methanogen populations affiliated with the Methanoculleus genus, and the populations affiliated with Methanoculleus chikugoensis assimilated acetate-derived carbon (acetate-C) in swine and dairy starved manure samples, respectively. Furthermore, carbon flow calculations indicated that these populations were the primary contributors to methane emissions during these anoxic SIP incubations. Comparative analysis of mcrA gene abundance (coding for a key enzyme of methanogenesis) for Methanoculleus spp. in fresh feces and a wider range of stored dairy or swine manure samples, by real-time quantitative PCR using newly designed specific primers, demonstrated that the abundance of this genus significantly increased during storage. The findings supported the involvement of these particular methanogen populations as methane emitters from swine and dairy manure storage tanks. The study revealed that the ability to assimilate acetate-C for growth in manure differed within the Methanoculleus genus.


Assuntos
Acetatos/metabolismo , Euryarchaeota/genética , Esterco/microbiologia , Animais , Proteínas de Bactérias/genética , Bovinos , Euryarchaeota/enzimologia , Dosagem de Genes , Genes Bacterianos , Cinética , Redes e Vias Metabólicas , Oxirredutases/genética , Filogenia , Sus scrofa
13.
Water Res ; 47(2): 737-46, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23206501

RESUMO

Greenhouse gas emissions represent a major environmental problem associated with the management of manure from the livestock industry. Methane is the primary GHG emitted during manure outdoor storage. In this paper, the variability of two swine and two dairy manure storage tanks was surveyed, in terms of physico-chemical and microbiological parameters. The impact of the inter-tank and spatio-temporal variations of these parameters on the methanogenic activity of manure was ascertained. A Partial Least Square regression was carried out, which demonstrated that physico-chemical as well as microbiological parameters had a major influence on the methanogenic activity. Among the 19 parameters included in the regression, the concentrations of VFAs had the strongest negative influence on the methane emission rate of manure, resulting from their well-known inhibitory effect. The relative abundance of two amplicons in archaeal fingerprints was found to positively influence the methanogenic activity, suggesting that Methanoculleus spp. and possibly Methanosarcina spp. are major contributors to methanogenesis in storage tanks. This work gave insights into the mechanisms, which drive methanogenesis in swine and dairy manure storage tanks.


Assuntos
Criação de Animais Domésticos , Fezes/microbiologia , Resíduos Industriais/análise , Esterco/microbiologia , Metano/metabolismo , Methanomicrobiaceae/crescimento & desenvolvimento , Animais , Pegada de Carbono , Bovinos , Fenômenos Químicos , Indústria de Laticínios , Ácidos Graxos Voláteis/análise , Ácidos Graxos Voláteis/metabolismo , Fezes/química , Concentração de Íons de Hidrogênio , Análise dos Mínimos Quadrados , Esterco/análise , Metano/análise , Methanomicrobiaceae/classificação , Methanomicrobiaceae/isolamento & purificação , Methanomicrobiaceae/metabolismo , Methanosarcina/classificação , Methanosarcina/crescimento & desenvolvimento , Methanosarcina/isolamento & purificação , Methanosarcina/metabolismo , Tipagem Molecular , Quebeque , Estações do Ano , Sus scrofa , Temperatura
14.
Appl Environ Microbiol ; 79(2): 424-33, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23104405

RESUMO

Methane emissions represent a major environmental concern associated with manure management in the livestock industry. A more thorough understanding of how microbial communities function in manure storage tanks is a prerequisite for mitigating methane emissions. Identifying the microorganisms that are metabolically active is an important first step. Methanogenic archaea are major contributors to methanogenesis in stored swine manure, and we investigated active methanogenic populations by DNA stable isotope probing (DNA-SIP). Following a preincubation of manure samples under anoxic conditions to induce substrate starvation, [U-(13)C]acetate was added as a labeled substrate. Fingerprint analysis of density-fractionated DNA, using length-heterogeneity analysis of PCR-amplified mcrA genes (encoding the alpha subunit of methyl coenzyme M reductase), showed that the incorporation of (13)C into DNA was detectable at in situ acetate concentrations (~7 g/liter). Fingerprints of DNA retrieved from heavy fractions of the (13)C treatment were primarily enriched in a 483-bp amplicon and, to a lesser extent, in a 481-bp amplicon. Analyses based on clone libraries of the mcrA and 16S rRNA genes revealed that both of these heavy DNA amplicons corresponded to Methanoculleus spp. Our results demonstrate that uncultivated methanogenic archaea related to Methanoculleus spp. were major contributors to acetate-C assimilation during the anoxic incubation of swine manure storage tank samples. Carbon assimilation and dissimilation rate estimations suggested that Methanoculleus spp. were also major contributors to methane emissions and that the hydrogenotrophic pathway predominated during methanogenesis.


Assuntos
Esterco/microbiologia , Metano/metabolismo , Methanomicrobiaceae/isolamento & purificação , Methanomicrobiaceae/metabolismo , Anaerobiose , Animais , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Marcação por Isótopo , Methanomicrobiaceae/classificação , Methanomicrobiaceae/genética , Dados de Sequência Molecular , Oxirredutases/genética , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Suínos
15.
Exp Cell Res ; 318(8): 925-35, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22394507

RESUMO

Evidence has suggested that STAT3 functions as an oncogene in gliomagenesis. As a consequence, changes in the inflammatory microenvironment are thought to promote tumor development. Regardless of its origin, cancer-related inflammation has many tumor-promoting effects, such as the promotion of cell cycle progression, cell proliferation, cell migration and cell survival. Given that IL-6, a major cancer-related inflammatory cytokine, regulates STAT3 activation and is upregulated in glioblastoma, we sought to investigate the inhibitory effects of the chemopreventive flavonoid quercetin on glioblastoma cell proliferation and migration triggered by IL-6, and to determine the underlying mechanisms of action. In this study, we show that quercetin is a potent inhibitor of the IL-6-induced STAT3 signaling pathway in T98G and U87 glioblastoma cells. Exposure to quercetin resulted in the reduction of GP130, JAK1 and STAT3 activation by IL-6, as well as a marked decrease of the proliferative and migratory properties of glioblastoma cells induced by IL-6. Interestingly, quercetin also modulated the expression of two target genes regulated by STAT3, i.e. cyclin D1 and matrix metalloproteinase-2 (MMP-2). Moreover, quercetin reduced the recruitment of STAT3 at the cyclin D1 promoter and inhibited Rb phosphorylation in the presence of IL-6. Overall, these results provide new insight into the role of quercetin as a blocker of the STAT3 activation pathway stimulated by IL-6, with a potential role in the prevention and treatment of glioblastoma.


Assuntos
Glioblastoma/metabolismo , Interleucina-6/metabolismo , Quercetina/farmacologia , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ciclina D1/biossíntese , Receptor gp130 de Citocina/biossíntese , Humanos , Janus Quinase 1/biossíntese , Metaloproteinase 2 da Matriz/biossíntese , Fosforilação/efeitos dos fármacos , Proteína do Retinoblastoma/metabolismo , Fator de Transcrição STAT3/antagonistas & inibidores
16.
Antimicrob Agents Chemother ; 56(4): 2162-5, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22252805

RESUMO

PC-1505 is a C34 peptide derived from the heptad repeat 2 region of HIV-1 gp41 conjugated to human serum albumin for sustained in vivo activity. One single preexposure dose of PC-1505 reduced viral RNA in HIV-1-infected SCID-hu Thy/Liv mice by 3.3 log10 and protected T cells from virus-mediated depletion. In contrast, a single preexposure dose of Truvada reduced viral RNA by only 0.8 log10 and was substantially less effective in preventing T cell depletion.


Assuntos
Inibidores da Fusão de HIV/farmacologia , Infecções por HIV/prevenção & controle , Peptídeos/farmacologia , Animais , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Combinação Emtricitabina e Fumarato de Tenofovir Desoproxila , Genes MHC Classe I/genética , Proteína do Núcleo p24 do HIV/sangue , Inibidores da Fusão de HIV/química , Infecções por HIV/virologia , Camundongos , Camundongos SCID , Compostos Organofosforados/farmacologia , Peptídeos/química , RNA Viral/sangue , Timócitos/efeitos dos fármacos , Timócitos/metabolismo , Timócitos/virologia
17.
FEMS Microbiol Ecol ; 80(2): 427-40, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22268671

RESUMO

Greenhouse gas emissions represent a major problem associated with manure management in the livestock industry. A prerequisite to mitigate methane emissions occurring during manure storage is a clearer understanding of how the microbial consortia involved in methanogenesis function. Here, we have examined manure stored in outdoor tanks from two different farms, at different locations and depths. Physico-chemical and microbiological characterization of these samples indicated differences between each tank, as well as differences within each tank dependent on the depth of sampling. The dynamics of both the bacterial and archaeal communities within these samples were monitored over a 150-day period of anaerobic incubation to identify and track emerging microorganisms, which may be temporally important in the methanogenesis process. Analyses based on DNA fingerprinting of microbial communities identified trends common among all samples as well as trends specific to certain samples. All archaeal communities became enriched with Methanoculleus spp. over time, indicating that the hydrogenotrophic pathway of methanogenesis predominated. Although the emerging species differed in samples obtained from shallow depths compared to deep samples, the temporal enrichment of Methanoculleus suggests that this genus may represent a relevant indicator of methanogenic activity in swine manure storage tanks.


Assuntos
Esterco/microbiologia , Metano/metabolismo , Methanomicrobiaceae/crescimento & desenvolvimento , Anaerobiose , Animais , Sequência de Bases , Biodegradação Ambiental , Impressões Digitais de DNA , Methanomicrobiaceae/genética , Methanomicrobiaceae/metabolismo , Dados de Sequência Molecular , Suínos
18.
Br J Nutr ; 108(8): 1390-8, 2012 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-22214882

RESUMO

The objectives of the study were to investigate the effects of dietary supplementation of flax hulls and/or flax oil on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)) in plasma and the mammary gland and the relative mRNA abundance of antioxidant genes in the mammary gland of dairy cows. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four treatments: control with no flax hulls (CONT), 9·88% flax hulls in the DM (HULL), control with 500 g flax oil/d infused in the abomasum (COFO), 9·88% flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). Plasma GPX activity tended to decrease with flax oil supplementation. Cows fed HULL had higher levels of CAT, GPX1 and SOD1 mRNA in the mammary gland and lower mRNA abundance of GPX3, SOD2 and SOD3 compared with those fed CONT. Abundance of CAT, GPX1, GPX3, SOD2 and SOD3 mRNA was down-regulated in the mammary gland of cows fed HUFO compared to those fed CONT. The mRNA abundance of CAT, GPX1, GPX3 and SOD3 was lower in the mammary gland of cows fed COFO than in the mammary gland of cows fed CONT. The present study demonstrates that flax hulls contribute to increasing the abundance of some antioxidant genes, which can contribute to protecting against oxidative stress damage occurring in the mammary gland and other tissues of dairy cows.


Assuntos
4-Butirolactona/análogos & derivados , Antioxidantes/metabolismo , Enzimas/metabolismo , Linho/química , Lignanas/farmacologia , Óleo de Semente do Linho/farmacologia , Leite/metabolismo , 4-Butirolactona/sangue , 4-Butirolactona/metabolismo , Abomaso , Fenômenos Fisiológicos da Nutrição Animal/genética , Animais , Bovinos , Suplementos Nutricionais , Enzimas/sangue , Enzimas/genética , Feminino , Expressão Gênica/efeitos dos fármacos , Lactação , Lignanas/sangue , Lignanas/metabolismo , Óleo de Semente do Linho/administração & dosagem , Preparações de Plantas , RNA Mensageiro/metabolismo , Sementes/química
19.
FEMS Microbiol Lett ; 325(2): 115-22, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22093027

RESUMO

Understanding the ecology of methanogens in natural and engineered environments is a prerequisite to predicting or managing methane emissions. In this study, a novel high-throughput fingerprint method was developed for determining methanogen diversity and relative abundance within environmental samples. The method described here, designated amplicon length heterogeneity PCR of the mcrA gene (LH-mcrA), is based on the natural length variation in the mcrA gene. The mcrA gene encodes the alpha-subunit of the methyl-coenzyme M reductase, which is involved in the terminal step of methane production by methanogens. The methanogenic communities from stored swine and dairy manures were distinct from each other. To validate the method, methanogenic communities in a plug flow-type bioreactor (PFBR) treating swine manure were characterized using LH-mcrA method and correlated to mcrA gene clone libraries. The diversity and relative abundance of the methanogenic groups were assessed. Methanobrevibacter, Methanosarcinaceae, Methanoculleus, Methanogenium, Methanocorpusculum and one unidentified group were assigned to particular LH-mcrA amplicons. Particular phylotypes related to Methanoculleus were predominant in the last compartment of the PFBR where the bulk of methane was produced. LH-mcrA method was found to be a reliable, fast and cost-effective alternative for diversity assessment of methanogenic communities in microbial systems.


Assuntos
Impressões Digitais de DNA/métodos , Euryarchaeota/classificação , Oxirredutases/genética , Animais , Reatores Biológicos , Bovinos , DNA Arqueal/química , DNA Arqueal/isolamento & purificação , Euryarchaeota/enzimologia , Euryarchaeota/genética , Biblioteca Gênica , Esterco/microbiologia , Filogenia , Reprodutibilidade dos Testes , Análise de Sequência de DNA , Suínos
20.
J Dairy Res ; 78(1): 111-7, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21214967

RESUMO

Nutritional value is a priority in new product development. Using vegetable or marine oils, rich in polyunsaturated fatty acids, in dairy beverage formulations is an option to provide the consumers with healthier products. However, these formulations are prone to oxidation, which is responsible for rapid flavour degradation and the development of potentially toxic reaction products during storage. Flaxseed lignans, secoisolariciresinol diglucoside (SDG), and its mammalian metabolites have antioxidant activity and could be used in beverage formulations to prevent oxidation. Commercially available SDG extract was added to the formulation of dairy beverages enriched with flaxseed oil. As an alternative approach, dairy beverages were produced from milk naturally rich in SDG metabolites obtained through the alteration of cow diet. Resistance to oxidation was determined from the kinetics of hexanal and propanal production during heat and light exposure treatments. Increasing SDG concentration in dairy beverage slightly reduced redox potential but had no effect on oxygen consumption during oxidation treatments. The presence of SDG in dairy beverage significantly improved resistance to heat- and light-induced oxidation. However, purified enterolactone, a mammalian metabolite from SDG, prevented oxidation at much lower concentrations. The use of milk from dairy cow fed flaxseed meal did not improve resistance to oxidation in dairy beverage. Enterolactone concentration in milk was increased by the experimental diet but it remained too low to observe any significant effect on dairy beverage oxidation.


Assuntos
Antioxidantes/administração & dosagem , Ácidos Graxos Insaturados/química , Linho/química , Alimentos Fortificados , Lignanas/administração & dosagem , Leite/química , 4-Butirolactona/análogos & derivados , 4-Butirolactona/análise , 4-Butirolactona/metabolismo , 4-Butirolactona/farmacologia , Animais , Butileno Glicóis/administração & dosagem , Butileno Glicóis/metabolismo , Bovinos , Dieta , Feminino , Glucosídeos/administração & dosagem , Glucosídeos/metabolismo , Temperatura Alta , Lignanas/análise , Lignanas/metabolismo , Lignanas/farmacologia , Oxirredução , Estresse Oxidativo , Processos Fotoquímicos
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