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Leguminous plants grown in sewage sludge-amended soils can acquire nitrogen by assimilation of nitrate and ammonium from the soil solution or from atmospheric-dinitrogen (N2) fixation through association with N2-fixing bacteria. We proposed that operation of both metabolic processes could contribute to alleviate the impact of drought in sludge-treated plants. A greenhouse experiment was conducted to evaluate the involvement of nodule metabolism in the use efficiency of water and N in sludge-treated plants. Treatments comprised (1) plants inoculated with rhizobia and amended with sewage sludge; (2) plants inoculated with rhizobia without any amendment; and (3) noninoculated plants supplied with ammonium nitrate, each under well-watered and drought conditions. Under drought, sludge-treated plants had increased plant growth and higher photosynthetic and water-use efficiencies than untreated plants. Drought stimulated nitrate reductase and GS/GOGAT activities but did not affect the activities of phosphoenolpyruvate carboxylase and malate dehydrogenase or the leghemoglobin concentration. The results suggest that under drought conditions, both N2 fixation and nitrate assimilation in nodules of sludge-treated plants contributed to improve plant N supply and to increase the drought tolerance of alfalfa. [ABSTRACT FROM AUTHOR]

Abstract: Symbiotic association of legumes with rhizobia frequently results in higher photosynthesis and soluble carbohydrates in comparison with nitrate-fed plants, which might improve its potential for biomass conversion into bioethanol. A greenhouse experiment was conducted to examine the effects of nitrogen source and water availability on stem characteristics and on relationships between carbohydrates, phenolic metabolism activity and cell wall composition in alfalfa (Medicago sativa L. cv. Aragón). The experiment included three treatments: (1) plants fed with ammonium nitrate (AN); (2) plants inoculated with rhizobia (R); and (3) plants inoculated with rhizobia and amended with sewage sludge (RS). Two levels of irrigation were imposed: (1) well-watered and (2) drought stress. Under well-watered conditions, nitrogen-fixing plants have increased photosynthesis and stem fermentable carbohydrate concentrations, which result in higher potential for biomass conversion to bioethanol than in AN plants. The latter had higher lignin due to enhanced activities of phenolic metabolism-related enzymes. Under drought conditions, the potential for bioethanol conversion decreased to a similar level in all treatments. Drought-stressed nitrogen-fixing plants have high concentrations of fermentable carbohydrates and cell wall cellulose, but ammonium nitrate-fed plants produced higher plant and stem biomass, which might compensate the decreasing stem carbohydrates and cellulose concentrations. [Copyright &y& Elsevier]

Abstract: Sewage sludge has been used as N fertilizer because it contains some of inorganic N, principally as nitrate and ammonium ions. However, sewage sludge addition to legumes could result in impaired nodule metabolism due to the presence of inorganic N from sludge. A greenhouse experiment was conducted to examine the effects of sewage sludge on growth, photosynthesis, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa L. cv. Aragón). Plants were grown in pots with a mixture of perlite and vermiculite (2:1, v/v). The experiment included three treatments: (1) plants inoculated with rhizobia and amended with sewage sludge at rate of 10% (w/w) (RS); (2) plants inoculated with rhizobia without any amendment (R); and (3) non-inoculated plants fed with ammonium nitrate (N). N2-fixing plants had lower growth and sucrose phosphate synthase activity but higher photosynthesis than nitrate-fed plants because they compensated the carbon cost of the rhizobia. However, sewage sludge-treated plants evidenced a loss of carbon sink strength due to N2 fixation by means of decreased photosynthetic capacity, leaf chlorophylls and N concentration in comparison to untreated plants. Sewage sludge did no affect nodulation but decreased nodule enzyme activities involved in carbon and N metabolisms that may lead to accumulation of toxic N-compounds. [ABSTRACT FROM AUTHOR]

This paper reports four cases of nasal polyps in adult sheep from Piedmont and Sicily farms. The clinical course and post-mortem findings are described. Macroscopically numerous nasal polyps obstructing the nasal cavities, with the erosion of nasal concha, were observed. Histologically the neoformations, consisting of a different number of fusiform fibrocytic cells arranged in a variable amount of amorphous mesenchymal matrix, were located in the submucosa and covered by a simple disorganized columnar epithelium. Non-suppurative infiltration was also observed. Microbiological investigations revealed positivity for Pseudomonas aeruginosa only in one case; no bacteria were isolated in polyps collected from the other three sheep. Chronic and massive infestation by Oestrus ovis was present in three cases. The etiology and pathogenesis of these proliferations remain to be clarified, even if the authors postulate that one biological agent (bacterium or parasite) may have been responsible for the reaction of the nasal mesenchyma. [ABSTRACT FROM AUTHOR]

Abstract: Mycobacterium bovis recognizes as hosts a wide spectrum of animal species. In particular epidemiological situations, high prevalence of infection is found also in pigs. In the present study, we evaluated the capability of the interferon-gamma (IFN-γ) assay to identify pigs infected with M. bovis. The results of the immune-diagnosis were correlated to the findings of the post mortem inspection and the bacterial culture of lymph nodes. Blood samples of 146 pigs, belonging to a local breed of Sicily reared in free or semi-free roaming conditions, were collected to assess the specificity and the sensibility of the IFN-γ assay. Thirty-one pigs, from M. bovis free herds, did not react to the IFN-γ assay, yielding a specificity of 100%. The IFN-γ assay identified 15 out of 19 animals positive to the bacterial culture and 22 out of 26 animals with tuberculous lesions, with a sensibility of 78.9–84.6%, respectively. Out of 26 reactors to the test, 15 pigs (57.7%) confirmed to be infected after the bacterial culture and 22 (84.6%) had tuberculous lesions. The IFN-γ assay was able to reveal 4 animals with no visible lesions (NVL). Together, these findings support the feasible use of the IFN-γ assay as an intra vitam tool for the surveillance and management of M. bovis infection in swine populations. [Copyright &y& Elsevier]