111 resultados para Unfolded protein response

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Temperament in cattle is defined as the fear-related behavioral responses when exposed to human handling. Our group evaluates cattle temperament using 1) chute score on a 1 to 5 scale that increases according to excitable behavior during restraint in a squeeze chute, 2) exit velocity (speed of an animal exiting the squeeze chute), 3) exit score (dividing cattle according to exit velocity into quintiles using a 1 to 5 scale where 1 = cattle in the slowest quintile and 5 = cattle in the fastest quintile), and 4) temperament score (average of chute and exit scores). Subsequently, cattle are assigned a temperament type of adequate temperament (ADQ; temperament score <= 3) or excitable temperament (EXC; temperament score > 3). To assess the impacts of temperament on various beef production systems, our group associated these evaluation criteria with productive, reproductive, and health characteristics of Bos taurus and Bos indicus-influenced cattle. As expected, EXC cattle had greater plasma cortisol vs. ADQ cattle during handling, independent of breed type (B. indicus x B. taurus, P < 0.01; B. taurus, P < 0.01; B. indicus, P = 0.04) or age (cows, P < 0.01; heifers or steers, P < 0.01). In regards to reproduction, EXC females had reduced annual pregnancy rates vs. ADQ cohorts across breed types (B. taurus, P = 0.03; B. indicus, P = 0.05). Moreover, B. taurus EXC cows also had decreased calving rate (P = 0.04), weaning rate (P = 0.09), and kilograms of calf weaned/cow exposed to breeding (P = 0.08) vs. ADQ cohorts. In regards to feedlot cattle, B. indicus EXC steers had reduced ADG (P = 0.02) and G:F (P = 0.03) during a 109-d finishing period compared with ADQ cohorts. Bos taurus EXC cattle had reduced weaning BW (P = 0.04), greater acute-phase protein response on feedlot entry (P <= 0.05), impaired feedlot receiving ADG (P = 0.05), and reduced carcass weight (P = 0.07) vs. ADQ cohorts. Acclimating B. indicus x B. taurus or B. taurus heifers to human handling improved temperament (P <= 0.02), reduced plasma cortisol (P < 0.01), and hastened puberty attainment (P <= 0.02). However, no benefits were observed when mature cows or feeder cattle were acclimated to human handling. In conclusion, temperament impacts productive, reproductive, and health characteristics of beef cattle independent of breed type. Hence, strategies to improve herd temperament are imperative for optimal production efficiency of beef operations based on B. taurus and B. indicus-influenced cattle.

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The localization of the glucocorticoid-inducible protein annexin 1 (ANX-1) in leukocytes during the process of experimental inflammation has been studied using immunocytochemistry. ANX-1 immunoreactivity was detected in extravasated neutrophils and eosinophils as well as in resident tissue mast cells. Following injection of carrageenin, the mesenteric tissue was highly inflamed with large presence of leukocytes (predominantly neutrophils with a small percentage of eosinophils) adherent to post-capillary venules and extravasated in the perivascular tissue. ANX-1 immunoreactivity was detected in the cytosol of neutrophils and eosinophils mainly associated with granules and/or vesicles. A good degree of localization in the endosomes was observed in the neutrophils, In both cell types, some ANX-1 immunoreactivity in the nucleus and in the plasma membrane was also detected. Resident mast cells were also activated. Mast cells were positive for ANX-1, without apparent changes in protein content in relation to their activation status. Degranulated mast cells still presented ANX-1 associated with the granule matrix. In conclusion, this study demonstrated the presence of ANX-1 in leukocytes that play a central role in the host inflammatory response. These are the extravasating polymorphonuclear cells, or the resident mast cells. These data provide morphological support to the notion that endogenous and exogenous ANX-1 are able to modulate the reactivity of these cell types, and more generally, of the experimental inflammatory reaction.

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Respirometric experiments demonstrated that the oxygen uptake by Thiobacillus ferrooxidans strain LR was not inhibited in the presence of 200 mM copper. Copper-treated and untreated cells from this T. ferrooxidans strain were used in growth experiments in the presence of cadmium, copper, nickel and zinc. Growth in the presence of copper was improved by the copper-treated cells. However, no growth was observed for these cells, within 190 h of culture, when cadmium, nickel and zinc were added to the media. Changes in the total protein synthesis pattern were detected by two-dimensional polyacrylamide gel electrophoresis for T. ferrooxidans LR cells grown in the presence of different heavy metals. Specific proteins were induced by copper (16, 28 and 42 kDa) and cadmium (66 kDa), whereas proteins that had their synthesis repressed were observed for all the heavy metals tested. Protein induction was also observed in the cytosolic and membrane fractions from T. ferrooxidans LR cells grown in the presence of copper. The level of protein phosphorylation was increased in the presence of this metal.

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The development of a fever in response to intravenous (IV, 1.5 μg/kg body mass) and intracerebroventricular (ICV, 1.5 μg/animal) injections of Escherichia coli lipopolysaccharide (LPS) was studied in control, thyroidectomised and protein-calorie malnourished rabbits (New Zealand Whites, n = 55). ICV injection of LPS is control rabbits produced a fever response, the characteristics of which differed from those obtained after IV pyrogen injection. Thyroid deficiency caused an attenuated fever response, irrespective of whether LPS had been administered by IV or ICV injection. Protein-calorie malnourished rabbits showed a smaller fever response after IV or ICV pyrogen injections. Malnourished rabbits, refed over a period of 15 days, showed a typical biphasic fever response, but with lower magnitude than controls. The results of these experiments suggest that ICV injection of LPS is not an appropriate model for the study of fever mechanisms in disease states, and that the attenuated fever response observed in protein-calorie malnourished rabbits may be related, at least in part, to a decreased ability to produce the endogenous pyrogen interleukin-1.

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The individual effects of protein deficiency and energy restriction on liver response to low-hexachlorobenzene (HCB) exposure were investigated in adult male Wistar rats. In rats fed either the low-protein or control diet, the only effect caused by HCB was a decrease in paralysis time following an ip injection of zoxazolamine. This decrease was similar for both groups. In the animals subjected to energy restriction, HCB induced a greater decrease in paralysis time, an increase in the size of centrilobular hepatocytes, a lower liver DNA content and an increased concentration of HCB in the adipose tissue, compared with the control and protein-deficient groups. Our data suggest that energy restriction increases liver response to HCB, while protein deficiency does not impair the hepatic reaction to small doses of HCB exposure.

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Two experiments were conducted to compare broiler chicken responses to methionine and betaine supplements when fed diets with low protein and relatively high metabolizable energy levels (17%, 3.3 kcal/g) or moderate protein and lower metabolizable energy levels (24%, 3.0 kcal/g), resulting in different levels of carcass fat. In Experiment 1, the basal diets were formulated with corn, soybean meal, poultry by-product meal, and poultry oil. In Experiment 2, glucose monohydrate was also added, so that identical amino acid profiles could be maintained in the 17 and 24% protein diets. On average, feeding the 17 vs. 24% protein diet decreased 21-d body weight gain by 20%, increased feed conversion ratio (FCR) by 13%, and increased abdominal fat pad weight by 104%. Methionine and betaine supplements improved the performance of chicks fed the 24% protein diet in both experiments, as indicated by body weight gain and FCR. Only supplementary methionine increased performance of chicks fed 17% protein diets, and then only in Experiment 2. Neither methionine nor betaine decreased abdominal fat pad size in either experiment. Methionine supplementation decreased relative liver size and increased breast muscle protein. Both methionine and betaine increased sample feather weight, but when expressed as a percentage of body weight, no significant differences were detected. It is concluded that increasing carcass fat by manipulating percentage dietary protein level or amino acid balance does not influence betaine's activity as a lipotropic agent.