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81.
Vanessa Peripolli Ênio Rosa Prates Júlio Otávio Jardim Barcellos José Braccini Neto 《Animal Feed Science and Technology》2011,163(2-4):170-176
This study aimed at evaluating forage intake and digestibility in ruminants using fecal nitrogen content, as well as validating a non-linear model to estimate digestibility in ruminants. A total of 58 conventional metabolism trials, carried out with sheep fed 27 forages (offered pure or in mixture) used in Rio Grande do Sul (RS) during the period 1969–1989 was analyzed. OM intake and OM digestibility (OMD) results were regressed linearly against fecal N, and OMD was also estimated from fecal crude protein (N × 6.25) content by a non-linear regression model. Fecal nitrogen excretion estimated forage intake in sheep with an R2 = 0.73, whereas a low R2 value of 0.36 was observed for OMD estimates. The equation obtained using the non-linear model was OMD = 0.7326 ? 0.3598 exp [(?0.9052 CP (g/kg OM))/100]. The parameters a (0.7326) and b (0.3598) estimated by the equation for all forages were significant (P<0.00001) and there was no effect of type of forage (P=0.38). The mean prediction error (MSPE), was 0.2379, indicating that the equation fit well to the data. The difference between estimated and observed organic matter digestibility was mainly caused by random variation (0.9765). The results indicated that the equation using the non-linear model developed with all forages can be used with enough precision to estimate the OM digestibility of forage consumed by sheep in Rio Grande do Sul. 相似文献
82.
Iorio NL Lopes AP Schuenck RP Barcellos AG Olendzki AN Lopez GL dos Santos KR 《Microbiology and immunology》2011,55(1):28-33
Staphylococcus is the most prevalent pathogen causing bacteremia and many of its isolates possess the ability to form biofilm. In this study Staphylococcus isolates from the blood of patients with bacteremia were analyzed by two biofilm detection phenotypic methods: Congo red agar (CRA) and microtiter-plate adherence (MPA) in relation to the presence of ica genes, detected by PCR. Their oxacillin susceptibility was also evaluated. Among 127 isolates evaluated, 47 were S. aureus and 80 were coagulase negative staphylococci (CNS). Seventy-four (58.3%) isolates were mecA gene positive (27.7%S. aureus and 76.3% CNS isolates). Among the 40 S. aureus isolates which were positive for the ica genes, 25 (62.5%) were positive in MPA and 27 (67.5%) in CRA, whereas both methods combined detected 34 (85%) isolates as biofilm producers. Among 12 S. epidermidis isolates carrying ica genes, 8 were positive in MPA and 5 in CRA. The combination of CRA and MPA methods provided a better prediction of the presence of ica genes in S. aureus isolates than did either method alone. 相似文献
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Cericato L Neto JG Kreutz LC Quevedo RM da Rosa JG Koakoski G Centenaro L Pottker E Marqueze A Barcellos LJ 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2009,149(3):363-367
As in many aquatic environments, pollution is a widespread problem in Southern Brazil. In our previous work, we demonstrated that sublethal contamination with some agrichemicals impairs the capacity of fishes to elevate cortisol levels in response to an additional acute stressor. In earlier experiments, the experimental design did not allow us to conclude where this effect occurs. In the present work, we used the adrenocorticotropic hormone (ACTH) challenge test to help us identify if the impairment occur in the interrenal tissue. For this purpose, five experiments were conducted, each with one specific agrichemical (methyl-parathion, atrazine+simazine, atrazine, tebuconazole, and glyphosate) in sublethal concentrations of 16.6% of the LC(50-96h), as previously determined. Fish were subjected to the ACTH challenge test protocol as follows: group 1, were non-injected and maintained as the specific control group; group 2 received an injection of the vehicle alone (the saline group); and group 3 receive an injection of ACTH. One hour later, blood samples were taken from the caudal plexus, using sterile syringes. In all specific control groups, the injection of ACTH induced a strong rise in plasma cortisol, compared with the fish injected only with the vehicle and the non-injected group. Fish exposed to methyl-parathion and tebuconazole did not elevate cortisol in response to the ACTH injection, with values significantly lower than the control fish. Fish exposed to sublethal concentrations of atrazine+simazine, atrazine, and glyphosate showed a rise in plasma cortisol very similar to the control fish. We conclude that the ACTH challenge test revealed that R. quelen exposed to sublethal concentrations of tebuconazole and methyl-parathion had a reduced ability to elevate plasma cortisol in response to an intraperitoneal (i.p.) injection of exogenous ACTH, indicating that the interrenal tissue is the site of the impairment within the HPI axis. These ACTH challenge tests also revealed that the impairment of the cortisol response verified in fish exposed to atrazine+simazine and glyphosate, as shown in our previous work, seems to be related to steps of cortisol secretion in higher levels within the HPI axis. 相似文献
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Guy Barros Barcellos Rafael Andrade Caceres Walter Filgueira de Azevedo Jr. 《Journal of molecular modeling》2009,15(2):147-155
Bacillus anthracis has been employed as an agent of bioterrorism, with high mortality, despite anti-microbial treatment, which strongly indicates
the need of new drugs to treat anthrax. Shikimate pathway is a seven step biosynthetic route which generates chorismic acid
from phosphoenol pyruvate and erythrose-4-phosphate. Chorismic acid is the major branch point in the synthesis of aromatic
amino acids, ubiquinone, and secondary metabolites. The shikimate pathway is essential for many pathological organisms, whereas
it is absent in mammals. Therefore, these enzymes are potential targets for the development of nontoxic antimicrobial agents
and herbicides and have been submitted to intensive structural studies. The forth enzyme of this pathway is responsible for
the conversion of dehydroshikimate to shikimate in the presence of NADP. In order to pave the way for structural and functional
efforts toward development of new antimicrobials we describe the molecular modeling of shikimate dehydrogenase from Bacillus anthracis complexed with the cofactor NADP. This study was able to identify the main residues of the NADP binding site responsible
for ligand affinities. This structural study can be used in the design of more specific drugs against infectious diseases. 相似文献
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Bartira Ercília Pinheiro da Costa Priscilla Barcellos de Almeida Ioná Rosine Conceição Ivan Carlos Ferreira Antonello Domingos O. d’Avila Carlos Eduardo Poli-de-Figueiredo 《Cell biochemistry and biophysics》2010,58(2):69-73
Erythrocytes l-arginine uptake is conveyed by y+ and y+L membrane transport systems. Pre-incubation with N-ethylmaleimide for 10 min at
37°C inhibits the y+ system. The aim of this study was to determine the ideal pre-incubation temperature in evaluating y+
and y+L systems. Cells were pre-incubated with or without N-ethylmaleimide for 10 min at 4°C and 37°C. l-Arginine uptake was quantified by radioisotope and standard erythrocytes membrane flux methodology. Results demonstrate that
erythrocytes l-arginine content is depleted by pre-incubation at 37°C for 10 min, thus changing the V
max measurement. The inhibitory effect of N-ethylmaleimide pre-incubation was temperature independent and already complete after
1 min of incubation. No significant difference in kinetic parameters was detected between cells pre-incubated at 37°C or 4°C,
under zero-trans conditions. In conclusion, we suggest that measurement of erythrocytes l-arginine uptake by y+ and y+L systems could be carried out without N-ethylmaleimide pre-incubation at 37°C. 相似文献
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L. J. G. Barcellos G. F. Wassermann † A. P. Scott § V. M. Woehl † R. M. Quevedo I. Ittzés M. H. Krieger ‡ F. Lulhier ¶ 《Journal of fish biology》2002,61(3):751-763
Seepage water through a lake bottom and the layering of tight and high-permeable layers in the aquifer produce groundwater under greater pressure than the water column of the lake. This results in under-water springs and seepages. When spawning substrata were available, there was a spatial correlation between the degree of groundwater influx and the redd density of brown trout Salmo trutta . In high density spawning areas with > 100 observed redds ha−1 , the mean seepage water influx during spring was c . 1200 ml m−2 min−1 compared to a mean flux of 113 ml m−2 min−1 in low density spawning areas with 5–10 redds ha−1 . 相似文献
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Rachid MA Camargos ER Barcellos L Marques CA Chiari E Huang H Tanowitz HB Teixeira MM Machado CR 《Microbes and infection / Institut Pasteur》2006,8(8):2113-2119
Endothelin has been implicated in the pathogenesis of experimental and human Chagas' disease (American trypanosomiasis). In the present study, we tested the effect of bosentan, an antagonist of both ET(A) and ET(B) endothelin receptors, on parasitemia, histopathology (heart and diaphragm), heart levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-10, interferon (IFN)-gamma, CCL2, CCL3 and CCL5, and the serum levels of nitrate/nitrite (NOx). Bosentan treatment was accompanied by a significant increase in parasitemia and tissue parasitism or inflammation. In vehicle-treated rats, Trypanosoma cruzi infection increased the cardiac levels of TNF-alpha, IFN-gamma and IL-10, at day 9 post inoculation, and the TNF-alpha remained elevated until day 13. The infection also caused a significant increase in the cardiac levels of the chemokines CCL2 (9, 13 and 18 days) and CCL3 (13 and 18 days). Bosentan-treatment had no significant effect on the infection-associated increase in IFN-gamma and chemokine concentrations. There was a lower increase in IL-10 at day 9 and this was mirrored by a greater increase of TNF-alpha at day 13, in comparison with vehicle-treated rats. These latter findings correlated well with the enhanced inflammatory process in hearts of bosentan-treated infected rats. Bosentan treatment reduced the infection-associated increase in NOx serum concentration. Altogether, our data suggest that ET action on ET(A) and ET(B) receptors may play a role in the initial control of T. cruzi infection in rats probably by interfering in NO production. 相似文献
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