ABSTRACT
RESUMO O controle do crescimento microbiano é um desafio crescente na produção de petróleo e gás, uma vez que a presença de determinadas bactérias traz impactos econômica e ambientalmente negativos. As bactérias redutoras de sulfato (BRS) são particularmente problemáticas, uma vez que são responsáveis pela corrosão biológica ligada à produção de sulfeto de hidrogênio, efeito conhecido como souring. A principal forma de controle das BRS atualmente é a injeção de biocidas, no entanto essa estratégia, além de requerer aplicação contínua, tem se revelado pouco efetiva na eliminação de biofilmes e é associada a um alto risco de contaminação das águas. Portanto, é necessário que se busquem abordagens mais eficientes e específicas em relação ao controle microbiológico. O uso de vírus bacteriófagos vem ao encontro dessas necessidades, pois eles, após se multiplicarem, geralmente provocam a lise celular, liberando novas partículas virais e evitando que a bactéria se prolifere. Diante disso, este estudo propõe estabelecer um método para a concentração e a determinação da eficiência de recuperação de bacteriófagos de BRS presentes em água de reator oriunda de poços de petróleo. As amostras foram coletadas de dois reatores operados em batelada alimentada e que simulam um poço de petróleo. As amostras de água de reator foram primeiramente clarificadas, os vírus eluídos desse sedimento e, em seguida, concentrados por ultracentrifugação. O concentrado viral foi então purificado com Vertrel XF. Ensaios de semeadura experimental de miofago P1 nas amostras de água do reator revelaram taxa de recuperação viral de 27,7%, contra ao 16% obtidos com outros protocolos.
ABSTRACT The control of microbial growth is an increasing challenge in the production of oil and gas, since the presence of certain bacteria has economic and environmental negative impacts. Sulphate reducing bacteria are particularly problematic, since they are responsible for the biological corrosion associated with the production of hydrogen sulfide, an effect known as souring. The main form of control is the use of biocides; however, this strategy, in addition to requiring continuous application, has proven to be ineffective in the elimination of biofilms and is associated with a high risk of water contamination. Therefore, it is necessary to seek more efficient and specific approaches to microbiological control. The use of bacteriophage viruses meets these needs, because after they multiply, they usually cause cell lysis, releasing new viral particles and preventing the bacteria from proliferating. In view of this, this study proposes to establish a method for the concentration and detection of bacteriophages of Sulphate Reducing Bacteria present in reactor water from oil wells. The samples were collected from two reactors, operated in a batch fed to simulate an oil well. The reactor water samples were first clarified, viruses adsorbed to sediment were eluted and then concentrated by ultracentrifugation. The viral concentrate was then purified with Vertrel-XF. Experimental seeding of P1 myophage in water samples from the reactor revealed a viral recovery rate of 27.7%, compared to the 16% obtained by use of other protocols.
ABSTRACT
Background: Type 1 diabetes mellitus (DM1) can cause damage to several physiological systems.Objectives: To compare and characterize the effects of aerobic exercise training (ET) performed by swimming with those of ET performed on a treadmill on the skeletal muscle and heart of rats with DM1. Methods: 41 male Wistar rats were randomized into four groups: nondiabetic control (CTR), diabetic control (DMC), diabetic trained on the treadmill (DMT), and diabetic trained by swimming (DMS). The trained groups performed aerobic exercise training for 8 weeks, 5 times a week, 60 min per day. Exercise tolerance, blood glucose, body weight, wet weight of the skeletal muscles and left ventricle (LV), muscle glycogen, cross-sectional area of skeletal muscles, and cross-sectional diameter and collagen volume fraction of the LV were evaluated.Results: The results were expressed as mean ± standard deviation of the mean and submitted to two-way ANOVA with post-hoc Bonferroni test. Aerobic ET protocols applied to animals with DM1, regardless of the ergometer, showed satisfactory results (p < 0.05) when compared to the control groups: improved exercise tolerance, increased glycogen content of the soleus and extensor digitorum longus (EDL) muscles and increased cross-sectional diameter of the left ventricular cardiomyocytes. In some variables, such as exercise tolerance and cross-sectional area of the soleus and EDL muscles, DMT showed better results than DMS (p < 0.05). On the other hand, DMS showed increased cross-sectional diameter of cardiomyocytes when compared with the DMT group. Conclusion: Both aerobic ET protocols offered benefits to animals with diabetes; however, due to the specific characteristics of each modality, different physiological adaptations were observed between the trained groups
Subject(s)
Animals , Rats , Swimming , Exercise , Rats, Wistar , Diabetes Mellitus , Exercise Test , Body Weight , Data Interpretation, Statistical , Muscle, Skeletal , Guidelines as Topic , Models, Animal , Myocytes, Cardiac/physiology , Glycemic Index , Physical ExertionABSTRACT
Abstract Background: Baroreceptors act as regulators of blood pressure (BP); however, its sensitivity is impaired in hypertensive patients. Among the recommendations for BP reduction, exercise training has become an important adjuvant therapy in this population. However, there are many doubts about the effects of resistance exercise training in this population. Objective: To evaluate the effect of resistance exercise training on BP and baroreceptor sensitivity in spontaneously hypertensive rats (SHR). Method: Rats SHR (n = 16) and Wistar (n = 16) at 8 weeks of age, at the beginning of the experiment, were randomly divided into 4 groups: sedentary control (CS, n = 8); trained control (CT, n = 8); sedentary SHR (HS, n = 8) and trained SHR (HT, n = 8). Resistance exercise training was performed in a stairmaster-type equipment (1.1 × 0.18 m, 2 cm between the steps, 80° incline) with weights attached to their tails, (5 days/week, 8 weeks). Baroreceptor reflex control of heart rate (HR) was tested by loading/unloading of baroreceptors with phenylephrine and sodium nitroprusside. Results: Resistance exercise training increased the soleus muscle mass in SHR when compared to HS (HS 0.027 ± 0.002 g/mm and HT 0.056 ± 0.003 g/mm). Resistance exercise training did not alter BP. On the other hand, in relation to baroreflex sensitivity, bradycardic response was improved in the TH group when compared to HS (HS -1.3 ± 0.1 bpm/mmHg and HT -2.6 ± 0.2 bpm/mmHg) although tachycardia response was not altered by resistance exercise (CS -3.3 ± 0.2 bpm/mmHg, CT -3.3 ± 0.1 bpm/mmHg, HS -1.47 ± 0.06 bpm/mmHg and HT -1.6 ± 0.1 bpm/mmHg). Conclusion: Resistance exercise training was able to promote improvements on baroreflex sensitivity of SHR rats, through the improvement of bradycardic response, despite not having reduced BP.
Resumo Fundamento: Os barorreceptores atuam como reguladores da pressão arterial (PA); no entanto, sua sensibilidade encontra-se prejudicada em pacientes hipertensos. Dentre as recomendações para a redução da PA, o treinamento físico tem se tornado um importante adjunto na terapia dessa população. Porém, ainda há diversos questionamentos sobre os efeitos de treinamento físico resistido nessa população. Objetivo: Avaliar o efeito do treinamento físico resistido na PA e na sensibilidade de barorreceptores em ratos espontaneamente hipertensos (SHR). Método: Ratos SHR (n = 16) e Wistar (n = 16) com 08 semanas de idade foram aleatoriamente divididos em 4 grupos: controle sedentário (CS, n = 8); controle treinado (CT, n = 8); SHR sedentário (HS, n = 8) e SHR treinado (HT, n = 8). O treinamento físico foi realizado em aparato com degraus (1,1 × 0,18 m, 2 cm entre os degraus, 80° inclinação) com peso fixado na cauda, (5 vezes por semana durante 8 semanas). O controle barorreflexo da frequência cardíaca (FC) foi testado com estímulos de fenilefrina e nitroprussiato de sódio. Resultados: O treinamento resistido foi capaz de aumentar a massa muscular do sóleo em ratos SHR (HS 0,027 ± 0,002 g/mm e HT 0,056 ± 0,003 g/mm). Não houve alteração da PA com o treinamento. Por outro lado, houve melhora na resposta bradicárdica da sensibilidade barorreflexa no grupo HT (HS -1,3 ± 0,1 bpm/mmHg e HT -2,6 ± 0,2 bpm/mmHg), no entanto, a resposta taquicárdica não foi alterada pelo exercício resistido (CS -3,3 ± 0,2 bpm/mmHg, CT -3,3 ± 0,1 bpm/mmHg, HS -1,47 ± 0,06 e HT -1,6 ± 0,1). Conclusão: O exercício físico resistido foi capaz de otimizar a sensibilidade barorreflexa dos ratos SHR por meio da melhora à resposta bradicárdica, apesar de não alterar a PA.