Amount Of Siderophore Research Articles

Possible mechanisms of action of Bacillus wiedmannii AzBw1, a biocontrol agent of the root-knot nematode, Meloidogyne arenaria

BackgroundWith increased environmental concerns and restrictions of chemical control, the importance of other eco-friendly strategies for management of the nematodes is being substantially grown nowadays. One of the most well-known strategies that have attracted the attentions is biological control of these deleterious agents. In our previous study (Moslehi et al. in Egypt J Biol Pest Control 31:1–11, 2021), Bacillus wiedmannii AzBw1 was introduced as a robust antagonistic agent against root-knot nematode Meloidogyne arenaria. Present study addressed the possible mechanisms of action of this strain.ResultsBased on quantitative bioassays it was shown that the strain AzBw1 is able to produce considerable amount of siderophore, protease, and chitinase. In an in vitro assay conducted by bi-plate Petri dishes, it was shown that hatching of the nematode eggs, subjected to bacterial volatile compounds (BVCs) was 34% lower than those of mock-treated control eggs. On the other hand, mortality of BVC-treated juveniles was 33.5% higher than those of mock-treated control juveniles. The secretory proteins from the medium culture of strain AzBw1 were precipitated and fractionated by anion exchange chromatography (AEC). Fractions from AEC were checked for hydrolytic activity and nematicidal effect. It was found that the fractions with the highest protease activity have a strong nematicidal effect. In contrast, significant nematicidal effect in the fraction with Chitinase activity was detected.ConclusionThe results suggested that protease activity played a key role in strain AzBw1 antagonism against root-knot nematode, M. arenaria. Finally, nonvolatile organic compounds were also extracted from the medium culture after removing secretory proteins and enzymes. Obtained results showed that these metabolites had also a strong anti-nematode effect.

Phytomitigation potential and adaptive responses of helophyte Typha latifolia L. to copper smelter-influenced heavily multi-metal contamination.

The present study of phytomitigation potential and adaptive physiological and biochemical responses of helophyte Typha latifolia L. growing in water bodies at different distances from the century-old copper smelter (JSC "Karabashmed" Chelyabinsk Region, Russia) was conducted for the first time. This enterprise is one of the most dominant sources of multi-metal contamination for water and land ecosystems. The aim of the research was to assess the heavy metal (Cu, Ni, Zn, Pb, Cd, Mn, and Fe) accumulation, the photosynthetic pigment complex, and some redox reactions in T. latifolia from six differently technogenic impacted sites. In addition, the quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM) in rhizosphere sediments, as well as some plant growth-promoting (PGP) attributes of 50 isolates from each site, were determined. The water and sediment metal concentrations in highly contaminated sites exceeded the permissible/critical limits and were found much higher than that previously reported by other researchers while studying this helophyte. Both the degree of contamination and geoaccumulation indexes further elucidated extremely high contamination due to prolonged activity of copper smelter. T. latifolia accumulated significantly higher concentrations of the most of studied metals in its roost and rhizome with meager transfer to leaves (the translocation factors were less than one). Spearman's rank correlation coefficient showed a strong positive correlation between the metal concentration in sediments and its content in T. latifolia leaves (rs = 0.786 at p < 0.001 on average) and roots/rhizome (rs = 0.847 at p < 0.001 on average). In highly contaminated sites, the folia content of chlorophyll a and carotenoids decreased (by 30 and 38%, respectively), while lipid peroxidation enhanced (by 42%) on average compared to S1-S3 sites. These responses were accompanied by increasing non-enzymatic antioxidant content (soluble phenolic compounds, free proline, and soluble thiols) that allow plants to resist under significant anthropogenic loads. QMAFAnM in the five studied rhizosphere substrates varied insignificantly (2.5 × 106 - 3.8 × 107cfug-1 DW) and was decreased only in the most contaminated site (4.5 × 105). The proportion of rhizobacteria capable of fixing atmospheric nitrogen decreased by 1.7 times, solubilizing phosphates by 1.5 times, and synthesizing indol-3-acetic acid by 1.4 times in highly contaminated sites, while the amount of siderophore, 1-aminocyclopropane-1-carboxylate deaminase, and HCN producing bacteria did not considerably change. The results indicate high resistance of T. latifolia to prolonged technogenic impact, probably due to compensatory adaptive changes in the nonenzymatic antioxidant level and presence of beneficial microorganisms. Thus, T. latifolia was found to be a promising metal-tolerant helophyte that could help in mitigation of metal toxicity due to their phytostabilization even in heavily contaminated environment.

Efficiency of Pseudomonas spp.-based formulation for controlling root rot disease of black cumin under greenhouse and field conditions

Black cumin (Nigella sativa) is an important seed spices crop, Fusarium root rot is a serious fungal disease responsible for significant losses worldwide, the present work was planned to study the used of some strains of Pseudomonas spp. to reduce the root rot disease of black cumin caused by Fusarium solani. Three isolates of Pseudomonas spp. were recovered from rhizosphere of black cumin plants and they were identified as Psedomonas fluorescens (PF1, PF2) and P. aeruginosa (PF3). They were tested as formulation and suspension under greenhouse and field conditions against root rot disease to reduce the disease severity. The results show that P. fluorescens (PF1) as a suspension and formulation gave the highest effect in reducing the disease severity (7.70 and 7.73%) also reduce the number of pathogenic fungi than control. All tested bacteria increased seed production than infected control. The laboratory results show that PF1 gave highest amount of siderophores followed by PF3, while P. fluorescens (PF2) show a weak production. Also, all tested bacteria have ability to phosphate solubilization with different degree among them, PF3 has highly ablitity to phosphate solubiization followed by other isolates. It could be control of F. solani the causal of root rot under greenhouse and field condition with this bioagents and could recommend using these isolates to control of root rot diseases of N. sativa under Assiut conditions.

Evaluation of Stress-Induced Microbial Siderophore from Pseudomonas aeruginosa Strain S1 as a Potential Matrix Metalloproteinase Inhibitor in Wound Healing Applications.

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes capable of causing various inflammatory and various degenerative diseases if over-expressed. The active site of these enzymes is a zinc binding motif which binds to the specific site on the substrate and induce degradation. Hence an inhibitor is required to form a complex with zinc motif which hampers the binding ability of MMPs. To obtain novel MMPs inhibitor for wound healing, the chelating activity of siderophore from the microbial source was focused. During screening for siderophore production, strain S1 produced the highest amount of siderophore in the minimal salts medium. The isolate was confirmed as Pseudomonas aeruginosa strain S1 based on 16S rRNA gene sequencing and phylogenetic analysis. The activity of the siderophore was assayed using chrome azurol sulphonate and purified by the chromatographic techniques. The structural evidence through Fourier transform infrared and nuclear magnetic resonance spectra revealed that the isolated siderophore is a catecholate type with the distinctive characters. The positive results of calcein and fluozin-3 assays indicate that siderophore could bind to divalent metal ions, namely Fe(2+) and Zn(2+). As the siderophore compound focused on wound healing property, the in vitro studies revealed the viability of NH3T3 fibroblast cells and its efficiency in matrix modulating was confirmed through gelatin zymogram.

Siderophore production by Gram-negative rods isolated from human polymicrobial infections

Siderophore production by Gram-negative rods isolated from human polymicrobial infections A total of 137 strains isolated from 67 mixed bacterial infections were examined for production and interchangeability of siderophores. The isolates comprised 109 strains belonging to 15 species of Enterobacteriaceae and 28 isolates of 6 species of non-fermenting rods. In 36 mixed infections (53.7%), the strains secreted siderophores of the same type. This concerned mostly strains belonging to the Enterobacteriaceae (46.3%), which produced enterobactin. We selected 37 pairs of strains that produced different siderophores. The strains examined were not able to use siderophores produced by the other isolate of the pair, except for 3 strains of Pseudomonas aeruginosa that used chelators excreted by enterobactin-producing E. coli. Our research indicates that in mixed polymicrobial infections the interchangeability of siderophores is possible, although it seems to be rare. More common is the production and secretion of the same chelator by strains participating in one infection, which definitely leads to an increase in the amount of iron chelator at the site of infection and, consequently, may enhance the virulence potential of bacteria, as the amount of siderophore seems to be directly related to the pathogenicity of a strain.

Dissolution of iron hydroxides by marine bacterial siderophore

A series of laboratory experiments was conducted to investigate the dissolution behavior of goethite and poorly crystalline iron hydroxide (PCIH) in the presence of siderophore produced by a marine bacterium, Alteromonas haloplanktis. The amounts of siderophore in the experimental solutions are expressed by the iron complexing capacity (ICC). The experimental data indicate that both the dissolution rates and solubilities of ferric hydroxides increase with increasing contents of siderophore and [H +]. For example, in a solution of pH=8 and ICC=12 μM, the iron content of solution increased from <0.1 to 1.3 μM by reaction with PCIH for 80 h. This Fe content is more than 50 times the solubility value of amorphous Fe(OH) 3 in pure water at pH=8. At pH=4, with increasing ICC value from 0 to 12.9 μM, the dissolution rate of goethite increased from 1.5 to 9.5 (nM/h/m 2) and that of PCIH increased from 0.4 to 3.4 (nM/h/m 2). At ICC=12.9 μM, with increasing pH from 4 to 6.8, the dissolution rate of goethite decreased from 9.5 to 1.9 nM/h/m 2, whereas that of PCIH decreased from 3.4 to 0.7 nM/h/m 2. Our study suggests that most of the iron utilized by phytoplankton in the oceans may be liberated from ferric hydroxides in aeolian particles by siderophores generated by marine bacteria.

Is the fur gene of Rhizobium leguminosarum essential?

Using primers corresponding to conserved regions of the bacterial regulatory gene fur, a homologue of this gene from the genome of Rhizobium leguminosarum biovar viciae, the nitrogen-fixing symbiont of peas, was isolated and sequenced. The fur gene is normally expressed constitutively, independent of the presence of Fe in the medium, but in one Rhizobium strain it was transcribed at a low level. Attempts to isolate a fur knockout mutant failed, suggesting that the gene is essential for free-living growth. In other bacteria, certain fur mutations confer manganese resistance; however, none of the manganese-resistant mutants of R. leguminosarum which we isolated was corrected by the cloned fur gene. When the cloned R. leguminosarum fur gene was introduced into a fur mutant of Escherichia coli, it caused some Fe-dependent reduction in the amount of siderophore, indicating that it can function heterologously.

Partial repression of siderophore-mediated iron transport in Azotobacter vinelandii grown with mineral iron

Azotobacter vinelandii grown in iron-limited medium containing increased amounts of the minerals olivine or glauconite produced decreased amounts of siderophores and iron-repressible outer membrane proteins. These minerals caused a relatively rapid repression of the pyoverdin-type siderophore, azotobactin, and a slower repression of the catechol siderophores, azotochelin and aminochelin. A 77 000 molecular weight outer membrane protein also was repressed with increased mineral content of the medium, but coordinate repression with any one siderophore was not evident. Cells grown with increased mineral concentrations progressively lost siderophore-mediated iron-transport activity. This loss in activity had the greatest effect on azotobactin-mediated 55Fe uptake, but catechol siderophore mediated 55Fe uptake also was depressed. These results suggested that an additional component was required for maximal iron-transport activity promoted by all the siderophores of A. vinelandii.