Relationship between Paratuberculosis and the microelements Copper, Zinc, Iron, Selenium and Molybdenum in Beef Cattle

To study the deficiency of minerals and its relationship with Paratuberculosis, blood, serum, and fecal samples were obtained from 75 adult bovines without clinical symptoms of the disease and from two bovines with clinical symptoms of the disease, from two beef herds with a previous history of Paratuberculosis in the Province of Buenos Aires, Argentina. Serum samples were processed by ELISA and feces were cultured in Herrolds medium. Copper, zinc and iron in serum were quantified by spectrophotometry and selenium was measured by the activity of glutathione peroxidase. We also determined copper, zinc, iron and molybdenum concentrations in pastures and the concentration of sulfate in water. Mycobacterium avium subsp paratuberculosis (Map) was isolated from 17.3% of fecal samples of asymptomatic animals and from the fecal samples from the two animals with clinical symptoms. All the Map-positive animals were also ELISA-positive or suspect, and among them, 84.6% presented low or marginal values of selenium and 69.2% presented low or marginal values of copper. The two animals with clinical symptoms, and isolation of Map from feces and organs were selenium-deficient and had the lowest activity of glutathione peroxidase of all the animals from both herds. All the animals negative to Map in feces and negative to ELISA had normal values of Se, while 13.8% of animals with positive ELISA or suspect and culture negative presented low levels of Se. Half of the animals that were negative both for ELISA and culture in feces were deficient in copper but none of them presented low values of selenium. The content of molybdenum and iron in pasture was high, 2.5 ppm and 1.13 ppm in one herd and 2.5 ppm and 2.02 ppm in the other, respectively, whereas the copper:molybdenum ratio was 1.5 and 5.2, respectively. These results do not confirm an interaction between imbalances of the micronutrients and clinical Paratuberculosis, but show evidence of the relationship between selenium...

Intracellular inclusions of uncultured magnetotactic bacteria / Inclusiones intracelulares de bacterias magnetotáticas no cultivadas

Magnetotactic bacteria produce magnetic crystals in organelles called magnetosomes. The bacterial cells may also have phosphorus-containing granules, sulfur globules, or polyhydroxyalkanoate inclusions. In the present study, the ultrastructure and elemental composition of intracellular inclusions from uncultured magnetotactic bacteria collected in a marine environment are described. Magnetosomes contained mainly defect-free, single magnetite crystals with prismatic morphologies. Two types of phosphorus-containing granules were found in magnetotactic cocci. The most common consisted of phosphorus-rich granules containing P, O, and Mg; and sometimes also C, Na, Al, K, Ca, Mn, Fe, Zn, and small amounts of S and Cl were also found. In phosphorus-sulfur-iron granules, P, O, S, Na, Mg, Ca, Fe, and frequently Cl, K, and Zn, were detected. Most cells had two phosphorus-rich granules, which were very similar in elemental composition. In rod-shaped bacteria, these granules were positioned at a specific location in the cell, suggesting a high level of intracellular organization. Polyhydroxyalkanoate granules and sulfur globules were less commonly seen in the cells and had no fixed number or specific location. The presence and composition of these intracellular structures provide clues regarding the physiology of the bacteria that harbor them and the characteristics of the microenvironments where they thrive (AU)

Las bacterias magnetotácticas producen cristales magnéticos en orgánulos llamados magnetosomas. Además, pueden contener gránulos de fósforo, glóbulos de azufre o inclusiones de polihidroxialcanoatos. En este estudio se describe la ultraestructura y la composición elemental de las inclusiones intracelulares de bacterias magnetotácticas no cultivables extraídas de un medio marino. Los magnetosomas contenían principalmente cristales de magnetita individuales de morfología prismática sin defectos. En los cocos magnetotácticos se encontraron dos tipos de gránulos que contenían fósforo. Los más frecuentes fueron los gránulos ricos en fósforo que contenían P, O, Mg y, a veces también, C, Na, Al, K, Ca, Mn, Fe, Zn y pequeñas cantidades de S y Cl. En los gránulos de fósforo-azufre-hierro se detectó P, O, S, Na, Mg, Ca, Fe, y con frecuencia Cl, K y Zn. La mayoría de las células tenían dos gránulos ricos en fósforo, cuya composición elemental era muy parecida. En las bacterias de forma bacilar, estos gránulos estaban situados en determinados lugares de la célula, sugiriendo un alto nivel de organización intracelular. Los gránulos de polihidroxialcanoatos y los glóbulos de azufre eran menos frecuentes y no mostraban ninguna localización especial dentro de la célula ni tenían un número fijo. La presencia y composición de estas estructuras intracelulares proporciona pistas sobre la fisiología de la bacteria que las hospeda y sobre las características de los microambientes donde se desarrollan (AU)