000			02900nab a22003497a 4500
001			G65303
003			MX-TxCIM
005			20170719110407.0
008			121211b |||p||p||||||| |z||| |
022	0		_a0099-2240
040			_aMX-TxCIM
082	0	4	_a89-079421
100	1		_aHartmann, A.
245	0	0	_aInfluence of amino acids on nitrogen fixation ability and growth of Azospirillum spp
260			_c1988
340			_aPrinted
500			_aref
520			_aThe utilization of amino acids for growth and their effects on nitrogen fixation differ greatly among the several strains of each species of Azospirillum spp. that were examined. A. brasiliense grew poorly or not at all on glutamate, aspartate, serine, or histidine as the sole nitrogen and carbon sources. Nitrogen fixation by most A. brasiliense strains was inhibited only slightly even by 10 mM concentrations of these amino acids. However, A. lipoferum and A. amazonense grew very well on glutamate, aspartate, serine, or histidine as the sole nitrogen and carbon sources; nitrogen fixation (measured in presence of malate or sucrose) was severely inhibited by these amino acids. It was concluded that growth on histidine as the sole source of nitrogen, carbon, and energy may be used for the taxonomic characterization of Azospirillum spp. and for the selective isolation of A. lipoferum. The different utilization of various amino acids by Azospirillum spp. may be important for their establishment in the rhi zosphere and for their associative nitrogen fixation with plants. The physiological basis for the different utilization of glutamate by Azospirillum spp. was investigated further. A. brasiliense and A. lipoferum exhibited a high affinity for glutamate uptake (Km values for uptake were 8 and 40 micron resp.); the Vmax was 6 x higher in A. lipoferum than in A. brasiliense. At high substrate concentrations (10 mM), the nonsaturable compt of glutamate uptake was most active in A. lipoferum and A. amazonense. The glutamate dehydrogenase activity of A. lipoferum was 7 x higher and the glutamate oxalacetate transaminase activities were 3 to 5 x higher in A. lipoferum and A. amazonese than in A. brasiliense. Glutamate-grown A. brasiliense had high glutamine synthetase and ammonium uptake activities, whereas these activities were low in glutamate-grown A. lipoferum. Thus, Azospirillum spp. differ quantitatively and qualitatively in their amino acid metabolism
546			_aEnglish
595			_aAC
650	1	0	_aBacteria _91017
650	1	0	_aHuman nutrition
650	1	0	_aOrganic compounds
650	1	0	_aOrganic nitrogen compounds
650	1	0	_aPhysiological functions
650	1	0	_aSoil biology
650	1	0	_aSpirillaceae
700	1		_aBurris, R.H., _ecoaut.
700	1		_aFu, H., _ecoaut.
773	0		_tApplied and Environmental microbiology (USA). (Jan 1988). v. 54(1) p. 87-93
942			_cJA
999			_c18753 _d18753