Search results for "siderophore"

Pseudomonas lini sp. nov., a novel species from bulk and rhizospheric soils.

2002

The taxonomic position of eight fluorescent Pseudomonas strains isolated from bulk and rhizospheric soils, and from water was examined. These eight strains clustered in one phenon together with Pseudomomas mandelii (CFBP 4844T), but could still be differentiated from this type strain by four phenotypic features. The eight stains exhibited internal DNA-DNA hybridization values ranging from 60 to 100%, with deltaTm below 5 degrees C (3.9 and 4.3 degrees C) for the lowest values (60 and 66%). The percentages of hybridization with type or reference strains of other Pseudomonas species tested ranged from 12 to 60% (deltaTm = 5.5 degrees C), indicating that the eight isolates studied constituted …

Siderophore production in Aeromona spp. Isolated from European eel, Anguilla anfuilla L.

1991

Siderophore typing, a powerful tool for the identification of fluorescent and nonfluorescent Pseudomonas

2002

ABSTRACT A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. As a general rule, strains within a well-circumscribed taxonomic group, namely the species Pseudomonas brassicacearum , Pseudomonas fuscovaginae , Pseudomonas jessenii , Pseudomonas mandelii , Pseudomonas monteilii , “ Pseudomonas mosselii ,” “ Pseudomonas palleronii ,” Pseudomonas rhodesiae , “ Pseudomonas salomonii ,” Pseudomonas syringa…

Comparative Genomics Analysis of Keratin-Degrading Chryseobacterium Species Reveals Their Keratinolytic Potential for Secondary Metabolite Production

2021

A promising keratin-degrading strain from the genus Chryseobacterium (Chryseobacterium sp. KMC2) was investigated using comparative genomic tools against three publicly available reference genomes to reveal the keratinolytic potential for biosynthesis of valuable secondary metabolites. Genomic features and metabolic potential of four species were compared, showing genomic differences but similar functional categories. Eleven different secondary metabolite gene clusters of interest were mined from the four genomes successfully, including five common ones shared across all genomes. Among the common metabolites, we identified gene clusters involved in biosynthesis of flexirubin-type pigment, m…

Unravelling the modus operandi of phytosiderophores during zinc uptake in rice: the importance of geochemical gradients and accurate stability consta…

2020

Abstract Micronutrient deficiencies threaten global food production. Attempts to biofortify crops rely on a clear understanding of micronutrient uptake processes. Zinc deficiency in rice is a serious problem. One of the pathways proposed for the transfer of zinc from soils into rice plants involves deoxymugineic acid (DMA), a phytosiderophore. The idea that phytosiderophores play a wider role in nutrition of Poaceae beyond iron is well established. However, key mechanistic details of the DMA-assisted zinc uptake pathway in rice remain uncertain. In particular, questions surround the form in which zinc from DMA is taken up [i.e. as free aqueous Zn(II) or as Zn(II)–DMA complexes] and the role…

Siderophore production by environmental strains ofSalmonellaspecies

1989

Iron uptake mechanisms were investigated in different species of Salmonella isolated from environmental waters. All strains examined were able to grow in the presence of high concentrations (10 mM) of the iron chelator EDDA. All strains excreted phenolate and hydroxamate siderophores, as assessed by bioassays and chemical tests. Bioassays with different indicator strains showed that all Salmonella strains can cross-feed other Enterobacteria, as well as mutants of Salmonella typhimurium deficient in the Enterobactin system, suggesting that this siderophore may be produced by the environmental Salmonella strains. The siderophore aerobactin may also be produced by one of the strains, according…

Efficiency of dihydroxamic and trihydroxamic siderochelates to extract uranium and plutonium from contaminated soils

2021

International audience; Actinide-based mineral phases occurring in contaminated soils can be solubilized by organic chelators excreted by plants, such as citrate. Herein, the efficiency of citrate towards U and Pu extraction is compared to that of siderophores, whose primary function is the acquisition of iron(III) as an essential nutrient and growth factor for many soil microorganisms. To that end, we selected desferrioxamine B (DFB) as an emblematic bacterial trishydroxamic siderophore and a synthetic analog, abbreviated (LCy,Pr)H2, of the tetradentate rhodotorulic acid (RA) produced by yeasts. Firstly, the uranyl speciation with both ligands was assessed in the pH range 2–11 by potentiom…

High affinity iron-uptake systems in Vibrio damsela: role in the acquisition of iron from transferrin

1997

In this work, the high affinity iron-acquisition systems displayed by virulent and avirulent strains of Vibrio damsela have been investigated. This species is an autochthonous member of marine ecosystems that can behave as an opportunistic pathogen for fish and mammals. All strains tested (i) were able to grow under the restricted conditions imposed by the iron chelators transferrin (Tf) and EDDHA, (ii) secreted siderophores of hydroxamic type, other than aerobactin and desferal, that were able to stimulate the growth of the auxotroph mutant Arthrobacter flavescens JG9, and (iii) expressed common iron-regulated outer membrane proteins (IROMPs). No change in LPS patterns was observed in resp…

Isolation and Characterization of an Fe(III)-Chelating Compound Produced by Pseudomonas syringae

1986

The phytopathogenic bacterium Pseudomonas syringae produces a fluorescent pigment when it is grown in iron-deficient media. This pigment forms a very stable Fe(III) complex that was purified in this form by using a novel procedure based on ultrafiltration and column chromatography. The Fe(III) complex has a molecular weight of 1,100 and contains 1 mol of Fe(III). The pigment is composed of an amino acid moiety with three threonines, three serines, one lysine, δ- N -hydroxyornithine, and a quinoline-type fluorescent chromophore. These features and its stability constant (in the range of 10 32 ) suggest that the fluorescent pigment of P. syringae is related to the siderophores produced by an…

Siderophores and related outer membrane proteins produced by pseudomonads isolated from eels and freshwater.

1992

A total of 46 environmental pseudomonads, together with six type strains, were examined for their siderophore-producing activity. All strains were able to grow under iron-limiting conditions, gave orange halos in the CAS agar assay, and produced hydroxamates, and some of them also produced phenolate-type compounds. Bioassays showed that all strains, except Pseudomonas aeruginosa, promoted growth of mutant strain Arthrobacter flavescens JG-9, deficient in hydroxamate production, and some of them promoted growth of Salmonella typhimurium enb-1, which requires enterobactin for growth. The presence of iron-regulated outer membrane proteins was observed, the molecular size of the main induced pr…