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Brucellosis is a worldwide zoonotic infectious disease that has a significant economic impact on animal production and human public health. We characterized the gene expression profile of B. abortus-infected monocyte-derived macrophages (MDMs) from naïve cattle naturally resistant (R) or susceptible (S) to brucellosis using a cDNA microarray technology. Our data indicate that (1) B. abortus induced a slightly increased genome activation in R MDMs and a down-regulated transcriptome in S MDMs, during the onset of infection, (2) R MDMs had the ability to mount a type 1 immune response against B. abortus infection which was impaired in S cells, and (3) the host cell activity was not altered after 12 h post-B. abortus infection in R MDMs while the cell cycle was largely arrested in infected S MDMs at 12 h p.i. These results contribute to an improved understanding of how host responses may be manipulated to prevent infection by brucellae.

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Mycobacterium tuberculosis complex species survive and replicate in phagosomes of the host cell. Cell death (CD) has been highlighted as one of the probable outcomes in this host-pathogen interaction. Previously, our group demonstrated macrophage apoptosis as a consequence of Mycobacterium bovis infection. In this study, we aimed to identify the contribution of apoptotic effector elements in M. bovis-induced CD. Bovine macrophages were either infected with M. bovis (multiplicity of infection, 10:1) or treated with an M. bovis cell extract (CFE). Structural changes compatible with CD were evaluated. Chromatin condensation was increased three times by the CFE. On the other hand, a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay demonstrated that levels of DNA fragmentation induced by M. bovis and CFE were 53.7% +/- 24% and 38.9% +/- 14%, respectively, whereas control cells had a basal proportion of 8.9% +/- 4.1%. Rates of DNA fragmentation were unaffected by the presence of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (z-VAD). Cells treated with 100 mug of CFE for 12 h had a fivefold decrease in the level of mitochondrial outer membrane permeabilization compared to that of untreated cells. Neither M. bovis infection nor CFE treatment induced activation of caspase 3, 8, or 9. Translocation of apoptosis-inducing factor (AIF) to the nucleus was identified in 32% +/- 3.5% and 26.3% +/- 4.9% of M. bovis-infected and CFE-treated cells, respectively. Incubation of macrophages with z-VAD prior to infection did not alter the percentage of cells showing AIF translocation. Our data suggest that M. bovis-induced CD in bovine macrophages is caspase independent with AIF participation.

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Foram estudadas características da bioquímica do sangue, da pressão arterial e da freqüência de pulso de 12 bezerros mantidos sob anestesia por 13 horas, utilizando-se propofol para a indução e isofluorano para manutenção, associados à administração de morfina intra-tecal. Os valores de freqüência de pulso, pressão arterial e glicemia apresentaram pequenas variações e se mantiveram próximos dos valores de referência para bezerros anestesiados. Ao longo do período de anestesia houve aumento significativo, mas discreto, do hematócrito, hemoglobina, pCO2, CO2 total, bicarbonato e potássio. O pH do sangue, pO2, Na+ e Ca++ apresentaram reduções significativas. Este protocolo anestésico foi seguro para a manutenção de bezerros anestesiados por período prolongado.(AU)

Several arterial blood chemistry parameters, arterial pressure, and pulse frequency were assessed in 12 calves kept under anesthesia for 13 hours. Propofol and isoflurane were used for induction and maintenance, respectively, in association with intra-thecal injection of morphine. Pulse frequency, arterial pressure, and blood glucose levels had mild oscillations, with values close to the reference range for calves under anesthesia. There was a mild but significant increase in the packed cell volume, hemoglobin, pCO2, total CO2, bicarbonate, and K+, throughout the duration of the anesthesia, whereas blood pH, pO2, Na+, and Ca++ levels decreased significantly. This protocol proved safe for maintenance of calves under anesthesia for prolonged periods of time.(AU)

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Foram estudadas características da bioquímica do sangue, da pressäo arterial e da freqüência de pulso de 12 bezerros mantidos sob anestesia por 13 horas, utilizando-se propofol para a induçäo e isofluorano para manutençäo, associados à administraçäo de morfina intra-tecal. Os valores de freqüência de pulso, pressäo arterial e glicemia apresentaram pequenas variaçöes e se mantiveram próximos dos valores de referência para bezerros anestesiados. Ao longo do período de anestesia houve aumento significativo, mas discreto, do hematócrito, hemoglobina, pCO2, CO2 total, bicarbonato e potássio. O pH do sangue, pO2, Na+ e Ca++ apresentaram reduçöes significativas. Este protocolo anestésico foi seguro para a manutençäo de bezerros anestesiados por período prolongado.

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Infections with Salmonella serotypes are a major cause of food-borne diseases worldwide. Animal models other than the mouse have been employed for the study of nontyphoidal Salmonella infections because the murine model is not suitable for the study of Salmonella-induced diarrhea. The microbe has developed mechanisms to exploit the host cell machinery to its own purpose. Bacterial proteins delivered directly into the host cell cytosol cause cytoskeletal changes and interfere with host cell signaling pathways, which ultimately enhance disease manifestation. Recently, marked advances have been made in our understanding of the molecular interactions between Salmonella serotypes and their hosts. Here, we discuss the molecular basis of the pathogenesis of Salmonella-induced enteritis.

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Infections with Salmonella serotypes are a major cause of food-borne diseases worldwide. Animal models other than the mouse have been employed for the study of nontyphoidal Salmonella infections because the murine model is not suitable for the study of Salmonella-induced diarrhea. The microbe has developed mechanisms to exploit the host cell machinery to its own purpose. Bacterial proteins delivered directly into the host cell cytosol cause cytoskeletal changes and interfere with host cell signaling pathways, which ultimately enhance disease manifestation. Recently, marked advances have been made in our understanding of the molecular interactions between Salmonella serotypes and their hosts. Here, we discuss the molecular basis of the pathogenesis of Salmonella-induced enteritis

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The objective of this study was to determine if B. abortus rough mutant strains RB51 and rfbK are eliminated in goat milk. Thirty milk goats were divided into two groups. Group I was inoculated with 4x10(10) cfu/ml of B.abortus RB51 strain and Group II with 1x10(9) cfu/ml of B. abortus rfbK strain by subcutaneous route in the right axilary region. Milk samples were taken aseptically on a daily basis for the first 30 days and weekly for the second and third months. The samples were inoculated on Farrell's media and incubated under 5-10% CO(2) at 37 degrees C for 10 days. The suspicious colonies were recultured in Farrell's media. There were no isolations of bacteria with characteristics of Brucella from any of the milk samples collected during 90 days of the study. It was concluded that neither of the strains used at these doses were eliminated by milk in goats inoculated during lactation.

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Seventy-nine Mycobacterium bovis isolates recovered from Mexican and Texas cattle were categorized into 16 and 25 distinct types on the basis of IS6110 and direct-repeat fingerprint patterns, respectively. By using a combination of both fingerprint patterns, 30 distinct restriction fragment length polymorphism types were defined. Fifty-eight of 79 isolates (73%) were distributed among nine clusters. Clustered isolates were identified within herds, as well as in geographically disperse herds in Texas and Mexico. This observation is consistent with active transmission within herds and among herds, presumably as a result of active or historical cattle movements. The majority of bovine isolates (64 of 79) exhibited a single copy of IS6110. Interestingly, in contrast to previous studies, a high percentage of bovine isolates (15 of 79) exhibited multiple IS6110 copies (two to five) distributed among 11 different restriction fragment length polymorphism types. It is speculated that transmission from noncattle sources may be responsible. Continued fingerprinting of isolates originating from nonbovine sources and herd surveys is expected to provide useful information regarding the epidemiology of tuberculosis in this region.

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The results of the immune responses of immunised and chemoprophylactically treated calves to tick-borne (Boophilus microplus) challenge indicate that the system of immunisation was effective in protecting cattle against Anaplasma marginale, Babesia argentina (bovis), and B. bigemina. However, chemoprophylaxis was effective only against Babesia spp. but not against A. marginale. Both methods showed a substantial advantage over no control system when using native cattle breeds in a zone endemic for bovine anaplasmosis and babesiosis. Based on the net economic gain per calf starting the experiment, sizeable differences were noted at 308 days between the calves in the immunised group, chemoprophylaxis group, tick and gastrointestinal parasite control group and the experiment control group.

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The indirect fluorescent antibody test (IFAT) as used in Africa for detecting bovine trypanosomiasis was adapted for use in South America and evaluated. Antigen consisted of Trypanosoma vivax laden bovine blood fixed in a 60 : 40 : : acetone : methanol solution. The test detected initial titres of 1 : 50 and 1 : 100 at an average of 13.1 and 15.9 days post parasitaemia (PP). Maximum titres as high as 1 : 400 developed in eight calves at an average of 23.4 days PP. In another calf, 109 days PP were required. Efficacy in detecting sero-positive calves throughout the course of infection was 81.1 and 96.4 per cent at serum dilutions of 1 : 100 and 1 : 50 respectively. No false positive reactions occurred when sera from 36 haemoparasite-free calves were tested. Cross reactivity did not occur when sera from calves singularly infected with Trypanosoma theileri, T evansi, Anaplasma marginale, Babesia argentina, B bigemina and Eperythrozoon spp were similarly tested in the IFAT. No significant differences were found in IFAT results of surveys in which both conventional serum samples and sera eluted from dried blood samples on filter paper from the same calf were used.

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