Null cyclic ␤-1,2-glucan synthetase mutants (cgs mutants) were obtained from Brucella abortus virulent strain 2308 and from B. abortus attenuated vaccinal strain S19. Both mutants show greater sensitivity to surfactants like deoxycholic acid, sodium dodecyl sulfate, and Zwittergent than the parental strains, suggesting cell surface alterations. Although not to the same extent, both mutants display reduced virulence in mice and defective intracellular multiplication in HeLa cells. The B. abortus S19 cgs mutant was completely cleared from the spleens of mice after 4 weeks, while the 2308 mutant showed a 1.5-log reduction of the number of brucellae isolated from the spleens after 12 weeks. These results suggest that cyclic ␤-1,2-glucan plays an important role in the residual virulence of the attenuated B. abortus S19 strain. Although the cgs mutant was cleared from the spleens earlier than the wild-type parental strain (B. abortus S19) and produced less inflammatory response, its ability to confer protection against the virulent strain B. abortus 2308 was fully retained. Equivalent levels of induction of spleen gamma interferon mRNA and anti-lipopolysaccharide (LPS) of immunoglobulin G2a (IgG2a) subtype antibodies were observed in mice injected with B. abortus S19 or the cgs mutant. However, the titer of anti-LPS antibodies of the IgG1 subtype induced by the cgs mutant was lower than that observed with the parental S19 strain, thus suggesting that the cgs mutant induces a relatively exclusive Th1 response.Brucella abortus is an intracellular pathogen that causes abortion in bovines and can infect humans. Abortion in cattle is the consequence of the tropism that the bacterium has for the placenta of pregnant animals, in which it multiplies intracellularly (10). Brucellosis in humans is primarily a disease of the reticuloendothelial system, in which the bacteria multiply inside the phagocytic cell; the intermittent release of bacteria from the cells into the bloodstream causes undulant fever (17, 29). Brucellosis does not spread among humans; consequently, eradication of the disease from the natural reservoirs, cattle, pigs, sheep, goats, and other susceptible animals, will lead to elimination of human infection. In regions with high prevalence of the disease, the only way of controlling and eventually eradicating this zoonosis is by vaccination of all susceptible hosts and elimination of infected animals.Vaccination represents an important tool for the control of bovine brucellosis. One of the most used vaccines is the attenuated strain B. abortus S19 obtained spontaneously from the virulent strain B. abortus 2308 (24, 25, 26, 29). Live attenuated B. abortus S19 has served for many years as an effective vaccine to prevent brucellosis in cattle (8,18). The genetic defect that leads to attenuation of this strain has not yet been defined. B. abortus S19 has lost some essential unknown mechanism of virulence. Despite this fact, the vaccinal strain conserves some degree of virulence, being pathogenic for humans (37), and...

Nonstructural protein 1 (NS1) is secreted by dengue virus in the first days of infection and acts as an excellent dengue biomarker. Here, the direct electrical detection of NS1 from dengue type 2 virus has been achieved by the measurement of variations in open circuit potential (OCP) between a reference electrode and a disposable Au electrode containing immobilized anti-NS1 antibodies acting as immunosensor. Egg yolk immunoglobulin (IgY) was utilized for the first time as the biological recognition element alternatively to conventional mammalian antibodies in the detection of dengue virus NS1 protein. NS1 protein was detected in standard samples in a 0.1 to 10 µg.mL−1 concentration range with (3.2 ± 0.3) mV/µg.mL−1 of sensitivity and 0.09 µg.mL−1 of detection limit. Therefore, the proposed system can be extended to detect NS1 in real samples and provide an early diagnosis of dengue.

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An indirect enzyme-linked immunosorbent assay (IELISA), a competitive ELISA (CELISA), and a fluorescence polarization assay (FPA) for the presumptive serological diagnosis of swine brucellosis were evaluated using two populations of swine sera: sera from brucellosis-free Canadian herds and sera from Argentina selected based on positive reactions in the buffered antigen plate agglutination test (BPAT) and the 2-mercaptoethanol (2-ME) test. In addition, sera from adult swine from which Brucella suis was isolated at least once for each farm of origin were evaluated. The IELISA, CELISA, and FPA specificity values were 99.9, 99.5, and 98.3%, respectively, and the IELISA, CELISA, and FPA sensitivity values relative to the BPAT and the 2-ME test were 98.9, 96.6, and 93.8%, respectively. Actual sensitivity was assessed by using 37 sera from individual pigs from which B. suis was cultured, and the values obtained were as follows: BPAT, 86.5%; 2-ME test, 81.1%; IELISA, 86.5%; CELISA, 78.5%; and FPA, 80.0%.Brucella suis occurs naturally in the smooth phase. The smooth Brucella spp. share certain smooth lipopolysaccharide (SLPS) epitopes, resulting in extensive serological cross-reactions. For this reason, conventional serological tests for swine brucellosis use antigens from Brucella abortus rather than B. suis, as shown by extensive testing for swine brucellosis in the United States (6). Conventional serological tests (16) and indirect enzyme-linked immunosorbent assays (IELISAs) (4, 16) cannot identify animals infected with Yersinia enterocolitica O:9 because of epitopes shared with Brucella spp. (16), resulting in lower specificity values than assays such as the competitive ELISA (CELISA) and the fluorescence polarization assay (FPA), which are capable of distinguishing animals infected with cross-reacting microorganisms (8, 9, 15) or vaccinated with B. abortus strain 19 (11) from animals infected with B. abortus or B. suis. The specificity of conventional serological agglutination tests was further reduced by nonspecific antibody thought to be immunoglobulin M (IgM) (16).Due to the uncertain nature of serological reactions to Brucella in pigs, the screening buffered antigen plate agglutination test (BPAT) (2) and the 2-mercaptoethanol (2-ME) agglutination test (7) are currently used for the detection of B. suis in infected herds. Only a few studies have described the development of primary binding assays for the detection of antibody to B. suis (17,20).More recently the IELISA, the CELISA, and the FPA developed for the diagnosis of bovine brucellosis (10, 14) have been validated for the presumptive diagnosis of swine brucellosis (15). The aims of the present study were to evaluate the IELISA, CELISA, and FPA for diagnosis of porcine brucellosis in Argentina, compared with the BPAT and 2-ME test used as diagnostic tests in Argentina, and to confirm previous data. MATERIALS AND METHODSNegative sera. Sera from Canadian pigs with no clinical or epidemiological evidence of brucellosis (B. suis has not been detected in Canad...

Several reviews of denitrification have shown it to be an efficient process for treating high nitrate-loaded effluents from nuclear industries. However, stressful conditions adversely affect biological kinetic parameters and performance. Additionally, actual nuclear effluents contain multiple pollutants and radioactive emissions that could render implementation difficult. The objective of this study was to treat and recycle water from nuclear industries by using a mixture of blended real nuclear wastewater (BRNW). The process was carried out under physicochemical parameters control in a biological model to established a technical setup and to model the denitrification process in a real nuclear wastewater effluent. Denitrification processes were carried out in the wastewater sample under controlled ORP conditions by the Hill model to establish the kinetic model. The results show a complete elimination of nitrate by the bacteria. Indicators of biochemical reactions were used to obtain a model based on Monod and controlled ORP. The good fit of the proposed model was verified under empirical and simulated conditions. To establish optimal performance, it was necessary to add 3% v/v of methanol, as a carbon source, to remove the nitrate in BRNW. Isolation techniques confirmed that Pseudomonas spp. was the dominant bacteria. Gene expression demonstrated the lack of inhibition of the NosZ gene responsible for the reduction in nitric oxide, a “greenhouse gas”. Finally, COD and uranium were removed from the liquid by precipitation. At the end of the process, the treated effluent could potentially be reused in industrial processes, recycling most of the wastewater effluents.

This Article contains an error in the legend of Figure 3. "(a) Dynamic response of the proposed immunosensor upon the addition of 1 mg.mL −1 NS1 in the measuring cell. " should read: "(a) Dynamic response of the proposed immunosensor upon the addition of 1 μ g.mL −1 NS1 in the measuring cell. "

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.