ABSTRACT
Pyoverdin type siderophores produced by six fluorescent Pseudomonas strains isolated from different rhizospheres were purified and characterized. The purified ferri-pyoverdins were tested for their ability to promote the growth of other strains grown under iron deficiency conditions. Only the one obtained from Pseudomonas putida BTP1 did not act as a growth promoter. The structure of the BTP1 siderophore was elucidated by spectroscopic methods and degradation studies. It turned out that it contains a chromophore which differs from the one typical for pyoverdins insofar as it carries the carboxyl group in 3- rather than in 1-position ((3S)-5-amino-1,2-dihydro-8,9-dihydroxy-3H-pyrimido[1,2a]quinoline-3- carboxylic acid). The amino group of the chromophore is substituted with the 5-carboxyl group of L-glutamic acid and its carboxyl group with the N-terminus of the peptide L-Asp-L-Ala-L-Asp-D-N5-Ac-N5-OH-Orn-L-Ser-L-c-N5-OH-Orn. This isopyoverdin fits into the biogenetic scheme which postulates ferribactins as the precursors of pyoverdins.
Subject(s)
Oligopeptides/chemistry , Oligopeptides/metabolism , Pigments, Biological/biosynthesis , Pseudomonas putida/metabolism , Amino Acid Sequence , Amino Acids/analysis , Biotransformation , Isoelectric Focusing , Magnetic Resonance Spectroscopy , Molecular Sequence Data , Oligopeptides/isolation & purification , Pseudomonas putida/growth & development , Siderophores , Spectrometry, Mass, Fast Atom BombardmentABSTRACT
From a strain of Pseudomonas fluorescens pseudobactin and several related compounds were isolated and their structures were elucidated. In this way a reference compound (5) could be obtained for the unambiguous determination of the absolute configuration of C-1 of the pyoverdin chromophore in newly isolated representatives of this class.
Subject(s)
Oligopeptides/chemistry , Pseudomonas fluorescens/chemistry , Amino Acid Sequence , Genetic Variation , Ionophores/chemistry , Molecular Sequence Data , Molecular Structure , Oligopeptides/isolation & purification , Protein ConformationABSTRACT
Sixteen lots of rabies immune globulin (RIG) and six lots of rabies immune horse serum (RIS) from different producers were examined for rabies antibody by the standard mouse neutralization test (MNT) and the rapid fluorescent focus inhibition test (RFFIT). An equine rabies standard serum was assayed in parallel. In comparisons of RIS with this standard the MNT and RFFIT gave comparable results. In comparisons of RIG the antibody values in the MNT was two to ten times higher than that in the RFFIT in 15 out of 16 lots. The MNT and RFFIT are thus not fully comparable when measuring rabies antibodies in RIG. The choice of the titration method is obviously important in the measurement of the antibody concentration in RIG or RIS in IU against an equine rabies reference preparation. The described differences could have consequences for the use of RIG.
