Ministry of Agriculture

About: Ministry of Agriculture is a government organization based out in Rio de Janeiro, Brazil. It is known for research contribution in the topics: Biology & Chemistry. The organization has 1153 authors who have published 1189 publications receiving 14442 citations.

Development and standardization of a western blotting test for detection of antibodies against B. abortus

Abstract: Brucellosis is an infectious disease caused by bacteria of the genus Brucella spp. with diagnosis based on use of serological techniques. The present study aimed to develop and standardize a western blotting (WB) test for detection of antibodies against B. abortus. Samples from two groups of cattle were analyzed: group I: 60 serum samples from true positive and true negative vaccinated animals (30 positive samples from infected animals according to rose bengal test (RBT), 2-mercaptoethanol, serum agglutination test (SAT) and complement fixation test (CFT) and 30 RBT negatives samples); group II: 383 field samples (90 positive and 293 CFT negative sera). The most reactive band in the western blotting, which properly identified and separated infected from non - infected had a molecular weight of ≤ 20kDa. The sensitivity, specificity and accuracy of the WB compared to RBT was 93%, 99%, 98%, respectively and k= 0.938. When compared to CFT, the sensitivity, specificity and accuracy of the WB was 97%, 98% and 97%, respectively and k= 0.929. The WB developed and standardized in the present study is a serological test with potential use as a confirmatory test for the diagnosis of bovine brucellosis.

Influência da concentração de NaCl e pH na extração de ricina em torta de mamona (Ricinus communis L.) e sua caracterização por eletroforese

Abstract: Castor bean (Ricinus communis L.) is an oilseed crop of high economic value due to the fact of presenting a clearly defined market for the oil extracted from its seeds. Castor cake, which is a residue of oil extraction, is at the moment receiving special attention because of its high protein content. However, among the proteins found in this cake it is observed the presence of ricin, a cytotoxin, which turns this seed dangerous to be used as an alternative protein source for animal feed. The present research has the objective of identifying the best experimental treatment for extraction of ricin from castor cake, with the aim of future studies of loss of ricin integrity, which would ensure the safety of the product. With this aim, it was initiated the search for a buffer of higher capacity of proteins extraction, using the response surface methodology. A central composite design was developed in order to determine the best pH and NaCl concentration for extraction. Of the five different pH values (4.0, 4.6, 6.0, 7.4, 8.0) and NaCl (0.0M, 0.3M, 1.0M, 1.7M, 2.0M) used, the treatment containing 0.2M potassium phosphate / 1.7M NaCl pH 7.4 was chosen as the best. The amount of protein extracted in this treatment reached values four times larger than the minimum found in other treatment studied. The electrophoresis analysis showed that there was no preferential extraction of ricin in the treatments; however purification steps using dialysis and precipitation with ammonium sulfate led to a better resolution of the two polypeptide chains presents in ricin.

Survey and geographic distribution of chestnut blight in Portugal.

Abstract: Cryphonectria parasitica, the fungus that causes chestnut blight disease, was first described in Portugal (1929) on bark samples of Castanea crenata, collected in Beira Interior province. After this report, only in 1989 two disease foci were found on native European chestnut, C. sativa, in Tras-os-Montes e Alto Douro Province. To assess the current distribution of chestnut blight in Portugal (mainland, Azores and Madeira) a nationwide monitoring program was implemented. A major cooperative effort, involving all the Portuguese Forest and Agricultural Services, was created for this endeavor and coordinated by the National Forestry Station. A total of 191 chestnut stands was surveyed across the entire country. C. parasitica was isolated from 56.5% of the sampling sites (108 sites). Sampled parcels were digitally geo-referenced and mapped. In addition, a collection of C. parasitica isolates has been established and the study of the molecular variability of C. parasitica in Portugal is underway.