One of the most essential systems applied to the eradication of bovine tuberculosis by Mycobacterium bovis is the epidemiologic surveillance of animals slaughtered in abattoir by means of inspection and sample taking of lesions compatible with tuberculosis, confirming the existence of the disease through culture and molecular detection, which takes weeks before a result can be obtained. An interesting alternative is to develop high-throughput molecular systems for the direct detection of M. bovis on biological samples. In this sense, our research has developed a molecular detection system by means of a real time based PCR process which is applied directly to bovine biological samples and it allows to differentiate between Mycobacterium tuberculosis Complex, Mycobacterium avium Complex and other atypical mycobacteria that are interesting from the veterinary point of view. The sensitivity was analyzed by applying a conventional extraction system based on guanidine thiocyanate and a robotized system based on the selective magnetic capture of mycobacterial DNA. The molecular detection system showed a high specificity and a detection threshold of only 2-3 genomes. The sensitivity depended on the DNA extraction system being used and on the kind of lesions on which it was used; the sensitivity ranged from 61.11% for samples with non visible lesions to 80.64% for chronic lesions, with an average sensitivity of 73.87% when using the manual extraction system and between 27.77 and 74.19% (average sensitivity 47.74%) when using the automated robotic system. In conclusion, our multiplex real time PCR assay represents a fully controlled, highthroughput diagnostic tool for the rapid detection of Myobacterium presence directly in animal clinical specimens, which could be a practical tool in the context of bovine tuberculosis abattoir surveillance programs and granuloma submission programs.

Preincubation of synaptosome-rich homogenates of rat hypothalamus with melatonin resulted in significant decreases of norepinephrine, serotonin, dopamine and glutamate uptake. Melatonin inhibition was noncompetitive; apparent K_m’s of initial uptake processes were: (2.5 ± 0.3) × 10^–7Mfor norepinephrine, (2.6 ± 0.3) × 10^–7Mfor serotonin, (2.4 ± 0.4) × 10^–7Mfor dopamine and (1.0 ± 0.3) × 10^–7Mfor glutamate. Apparent K_¡’s for melatonin inhibition of transmitter uptake were: 0.64 ± 0.14 mM (norepinephrine), 0.23 ± 0.03 mM (serotonin), 0.51 ± 0.08 mM (dopamine) and 1.21 ± 0.10 mM (glutamate). Transmitter release evoked by increasing [K+] in medium to 30 mM was augmented by melatonin in a dose-dependent manner. Maximal effects were observed on serotonin release. Accumulation of ³H-melatonin within synaptosome-rich homogenates did not exhibit differences between 0 and 37 °C, indicating that the uptake of the hormone was not an active process. These results suggest that exogenously-administered melatonin may affect neurotransmitter accumulation and release in the hypothalamus by modification of the transmitter uptake mechanism rather than by competition with the transmitter for its uptake pump.

No abstract

Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species.

Melatonin administration or exposure of rats to darkness for two weeks induced comparable changes in pineal ultrastructure, compatible with a generalized organ's activation. These include an increased number of ribosomes, procentrioles and microtubules, prominent nucleoli and Golgi apparatus, and annulate lamellae. Melatonin treatment resulted in a dose-dependent increase of hydroxyindole-O-methyl transferase and serotonin-N-acetyltransferase activities. In addition it increased by 85% the colchicine binding capacity of pineal homogenates, an estimation of the microtubule protein content of the gland. Pineal norepinephrine turnover was not affected by melatonin treatment. These data indicate that the pineal itself is a target organ for exogenously administered melatonin. Key words: Pineal gland, melatonin, norepinephrine, tubulin.