Complexos de CoIII derivados da 2-acetilpiridina N(4)-R tiossemicarbazona (Hatc-R, R = alquil ou aril) foram caracterizados por análise elementar, espectroscopia na região do infravermelho, UV-Visível e ¹H RMN, voltametria cíclica (VC), medidas de condutividade e difração de raios X em monocristal. Os resultados obtidos são consistentes com a oxidação do centro de CoII para CoIII após a coordenação N,N,S-tridentada e monoaniônica dos ligantes tiossemicarbazonas, resultando em complexos octaédricos iônicos do tipo [Co(atc-R)2]Cl. Os estudos de eletroquímica mostram dois processos reversíveis, referentes aos pares redox CoIII/CoII e CoII/CoI, que são afetados pelo efeito indutivo dos grupos substituintes na posição N4 dos ligantes. Dois complexos de CoIII se mostraram satisfatoriamente ativos, com valores de concentração inibitória mínima abaixo de 10 µmol L- 1 e um deles apresentou muito baixa citotoxicidade contra células VERO e J774A.1 (IC50), conferindo-lhe altos índices de seletividade (SI > 10).

CoIII complexes derived from 2-acetylpyridine N(4)-R thiosemicarbazone (Hatc-R, R = alkyl, aryl) have been characterized by elemental analysis, FTIR, UV-Visible and ¹H NMR spectroscopies, cyclic voltammetry (CV), conductimetry measurements and single crystal X-ray diffractometry. The results obtained are consistent with the oxidation of the CoII center to CoIII upon coordination of the monoanionic N,N,S-tridentate thiosemicarbazone ligands, resulting in octahedral ionic complexes of the type [Co(atc-R)2]Cl. Electrochemistry studies show two reversible processes referring to the redox couples CoIII/CoII and CoII/CoI which can be modified by the inductive effects of the substituents groups at the N4 position of the ligands. Two CoIII complexes showed satisfactory activity with minimal inhibitory concentration value under 10 µmol L- 1 and one presented quite low cytotoxicity against VERO and J774A.1 cells (IC50), resulting in high selectivity index (SI > 10).

Quantitative polymerase chain reaction-high-resolution melting (qPCR-HRM) analysis was used to screen for mutations related to drug resistance in Mycobacterium tuberculosis. We detected the C526T and C531T mutations in the rifampicin resistance-determining region (RRDR) of the rpoB gene with qPCR-HRM using plasmid-based controls. A segment of the RRDR region from M. tuberculosis H37Rv and from strains carrying C531T or C526T mutations in the rpoB were cloned into pGEM-T vector and these vectors were used as controls in the qPCR-HRM analysis of 54 M. tuberculosis strains. The results were confirmed by DNA sequencing and showed that recombinant plasmids can replace genomic DNA as controls in the qPCR-HRM assay. Plasmids can be handled outside of biosafety level 3 facilities, reducing the risk of contamination and the cost of the assay. Plasmids have a high stability, are normally maintained in Escherichia coli and can be extracted in large amounts.

We assessed the performance of REMA in comparison with BACTEC MGIT 960 in the susceptibility testing of 80 Mycobacterium tuberculosis clinical isolates from Clemente Ferreira Institute against four drugs. REMA proved to be a rapid and accurate method, providing excellent correlation with BACTEC MGIT 960, with the exception of results for the ethambutol drug.

We report a comparative study of two DNA extraction techniques, thermolysis and chemical lysis (CTAB), for molecular identification and genotyping of M. tuberculosis. Forty DNA samples were subjected to PCR and the results demonstrated that with thermolysis it is possible to obtain useful data that enables fast identification and genotyping.

Rhodococcus equi has emerged as an opportunistic pathogen associated with pulmonary, invasive or systemic infections in immunocompromised patients. We report the identification of 51 R. equi isolates found in sputum samples of 546 individuals suspected to have pulmonary tuberculosis in two Public Health Hospital Units in Brazil. The epidemiology of R. equi infection as well as the phenotypic identification and drug susceptibility profile of isolates are described in this paper.

Quantitative trait loci (QTL) mapping in livestock allows the identification of genes that determine the genetic variation affecting traits of economic interest. We analyzed the birth weight and weight at 60 days QTL segregating on bovine chromosome BTA14 in a F2 resource population using genotypes produced from seven microsatellite markers. Phenotypes were derived from 346 F2 progeny produced from crossing Bos indicus Gyr x Holstein Bos taurus F1 parents. Interval analysis to detect QTL for birth weight revealed the presence of a QTL (p < 0.05) at 1 centimorgan (cM) from the centromere with an additive effect of 1.210 ± 0.438 kg. Interval analysis for weight at 60 days revealed the presence of a QTL (p < 0.05) at 0 cM from the centromere with an additive effect of 2.122 ± 0.735 kg. The region to which the QTL were assigned is described in the literature as responsible for some growth traits, milk yield, milk composition, fat deposition and has also been related to reproductive traits such as daughter pregnancy rate and ovulation rate. The effects of the QTL described on other traits were not investigated.

Segregation between a genetic marker and a locus influencing a quantitative trait in a well delineated population is the basis for success in mapping quantitative trait loci (QTL). To detect bovine chromosome 5 (BTA5) birth weight QTL we genotyped 294 F2 Gyr (Bos indicus) x Holstein (Bos taurus) crossbreed cattle for five microsatellite markers. A linkage map was constructed for the markers and an interval analysis for the presence of QTL was performed. The linkage map indicated differences in the order of two markers relative to the reference map (<A HREF="http://www.marc.usda.gov/">http://www.marc.usda.gov</A>). Interval analysis detected a QTL controlling birth weight (p < 0.01) at 69 centimorgans (cM) from the most centromeric marker with an effect of 0.32 phenotypic standard-error. These results support other studies with crossbred Bos taurus x Bos indicus populations.