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PubMed1985

Chemotherapeutic agents with an imidazole moiety. I. Synthesis and antifungal activities of 1-aryl-4-p-nitrophenylimidazoles.

The synthesis and antifungal activities of 1-aryl-4-p-nitrophenylimidazoles and their 2-mercaptoderivatives is reported. Antimicrobial data in comparison with antifungal antibiotic pyrrolnitrin attributed the best activity to 1-p-methoxyphenyl-4-p-nitrophenylimidazole. The tested compounds were prepared by reacting p-nitrophenacylanilines with potassium thiocyanate in acidic medium to afford 1-aryl-2-mercapto-4-p-nitrophenylimidazoles, which were then transformed into the title compound by treatment with nitric acid.

Antifungal Agents↗
PubMed1986

Detection of a new chloroperoxidase in Pseudomonas pyrrocinia.

A new chloroperoxidase could be detected in Pseudomonas pyrrocinia ATCC 15,958, a bacterium that produces the antifungal antibiotic pyrrolnitrin. This enzyme was separated from a ferriprotoporphyrin IX containing bromoperoxidase which was also produced by this bacterium. The enzyme is capable of catalyzing the chorination of indole to 7-chloroindole. This procaryotic chloroperoxidase requires the presence of H2O2 and can also brominate monochlorodimedone, but cannot catalyze its chlorination. This enzyme is the first chloroperoxidase described from procaryotic sources.

Chloride Peroxidase↗
PubMed1994

Purification and characterization of a novel metal-containing nonheme bromoperoxidase from Pseudomonas putida.

A novel bromoperoxidase was purified to homogeneity from the bacterium Pseudomonas putida IF-3 strain, which produces the antibiotic pyrrolnitrin. The enzyme had a molecular mass of 68,000 and was composed of two identical subunits (33,000). It was specific for I- and Br- and inactive toward Cl- and F- in the monochlorodimedone assay system. The optimum pH of the enzyme was around 4.2 and it rapidly lost its activity below 3.5, but it was stable over of range pH of 4 to 11. The purified enzyme was activated several fold by incubation with only cobalt ions, and did not contain an organic prosthetic group such as heme, flavin and cobalamin. Analyses of prosthetic metal compounds in the enzyme using plasma atomic emission spectroscopy (ICP-AES) combined with mass-spectroscopy (MS) and trace metal determination by high performance liquid chromatography (HPLC)-spectrometry, revealed that the enzyme contained 0.35 +/- 0.1 mol of cobalt ions, 1.0 +/- 0.2 mol of nickel ions, 0.8 +/- 0.2 mol of zinc ions and 2.0 +/- 0.2 mol of ferric iron per mol of enzyme, assuming the molecular weight of 68,000. There was no trace of vanadium in the enzyme, unlike in some nonheme haloperoxidases. Thus the bromoperoxidase of P. putida is a novel nonheme metal-containing bromoperoxidase.

Amino Acid Sequence↗
PubMed2004

A novel halogenase gene from the pentachloropseudilin producer Actinoplanes sp. ATCC 33002 and detection of in vitro halogenase activity.

A novel halogenase gene (halB) was isolated from a cosmid library of the pentachloropseudilin producer Actinoplanes sp. ATCC 33002. The halogenase has high identity (55%) to the flavin-dependent monodechloroaminopyrrolnitrin-3 halogenase from pyrrolnitrin biosynthesis and to the halogenases PltM and PltA (35% and 28%, respectively) involved in pyoluteorin biosynthesis. The enzyme has no sequence similarity to the flavin-dependent tryptophan halogenases. The gene could be heterologously expressed in Pseudomonas aureofaciens ACN as soluble protein. Chlorinating activity of HalB was shown with two synthetic substrates with structural similarity to pentachloropseudilin. HalB is the first halogenase from an actinomycete and only the third halogenase for which halogenating activity could be demonstrated in vitro.

Amino Acid Sequence↗
PubMed2005

Residue level, persistence, and storage performance of citrus fruit treated with fludioxonil.

The potential of postharvest dip treatments with fludioxonil (FLU) (a synthetic analogue of the bacterial metabolite of pyrrolnitrin), in controlling postharvest decay caused by Penicillium digitatum and Penicillium italicum of citrus fruit was investigated in comparison with the conventional fungicide imazalil (IMZ). The ultrastructural changes of fruit epicuticular wax was investigated as a function of water dip temperature, and the possible role of these changes was related to residue accumulation under FLU treatment. Residues retained by fruit were determined as a function of fungicide concentration, dip temperature, and fruit storage conditions. Scanning electron microscopy analysis revealed that fruit dipping in water at 30 or 40 degrees C did not cause differences in cuticular wax's ultrastructure in comparison to control fruit, while treatments at 50, 55, or 60 degrees C caused the disappearance of wax platelets, resulting in relatively homogeneous skin surface, due to partial "melting" of epicuticular wax. Residues of FLU in fruit treated at 20 or 50 degrees C were significantly correlated with the doses of fungicide applied. When equal amounts of fungicide were employed, the residue concentrations were notably higher (from 2.6- to 4-fold) in fruit treated at 50 degrees C than in fruit treated at 20 degrees C. The dissipation rate of FLU in "Salustiana" and "Tarocco" oranges was lower in fruit subjected to treatment at 50 degrees C. The minimal FLU concentration for almost complete decay control in artificially wounded fruit during 7-d storage at 20 degrees C was 400 mg/L active ingredient (ai) in fruit treated at 20 degrees C and 100 mg/L ai in fruit treated at 50 degrees C. Results on nonwounded Tarocco oranges subjected to 3 weeks of simulated quarantine conditions at 1 degrees C, plus 6 weeks of standard storage at 8 degrees C and an additional two weeks of simulated marketing period (SMP) at 20 degrees C revealed that almost complete decay control with FLU applications of 100 mg/L at 50 degrees C and 400 mg/L at 20 degrees C resulted in ca. 0.8 mg/kg FLU fruit residues, in agreement with results on wounded citrus fruit. When equal concentrations and temperatures were applied, FLU treatments were as effective as IMZ. In vitro trials showed a low sensitivity to FLU against P. digitatum and P. italicum isolates. MIC values for the complete inhibition of mycelium growth were >or=100 microg/mL, while ED(50) values ranged from 0.1 to 1 microg/mL for P. digitatum and from 1 to >100 microg/mL for P. italicum. The latter result suggests that care should be taken to avoid exclusive application of FLU in a sustainable program for management of fruit decay. However, integrating fungicide application and hot water dip may reduce the possibility of selecting fungicide-resistant populations of the pathogen, by increasing the effectiveness of the treatment.

Citrus↗
PubMed1995

Antifungal agents. 9. 3-Aryl-4-[alpha-(1H-imidazol-1-yl)arylmethyl]pyrroles: a new class of potent anti-Candida agents.

A new class of potent antifungal agents, namely, 3-aryl-4-[alpha-(1H-imidazol-1-yl)arylmethyl]-pyrroles, is described. These compounds are related to bifonazole and pyrrolnitrin, two compounds belonging to the class of antimycotic drugs. The synthesis of the title pyrroles has been performed starting from 1,3-diaryl-2-propen-1-ones, which were reacted with tosylmethyl isocyanide to give 3-aroyl-4-arylpyrroles. Reduction of the resulting compounds by lithium aluminum hydride furnished the related alcohols, which were treated with 1,1'-carbonyldimidazole to afford the required imidazole derivatives. Forty-four new pyrroles which incorporate an (arylmethyl)imidazole moiety in the 3-arylpyrrole structure were prepared by the above procedure and tested in vitro against Candida albicans and Candida spp. Among test compounds, 10 were found to be highly active against C. albicans. The most active derivative (27) was twice as potent (MIC90) as bifonazole, and its activity was 4 times greater than those of miconazole and ketoconazole. The other nine compounds showed antifungal activity of the same order of that of bifonazole and were ca. 2 times as active as miconazole and ketoconazole. Derivatives 21 and 27 tested in vivo against C. albicans A170 were shown to be highly effective in rabbit skin candidosis. Pharmacological studies on compounds 27 and other related pyrroles (19, 35, 36, 38, 39, and 49) are in progress to select one of them as a potential candidate for clinical experiments.

Adult↗
PubMed2002

Antifungal agents. 10. New derivatives of 1-[(aryl)[4-aryl-1H-pyrrol-3-yl]methyl]-1H-imidazole, synthesis, anti-candida activity, and quantitative structure-analysis relationship studies.

The synthesis, anti-Candida activity, and quantitative structure-activity relationship (QSAR) studies of a series of 2,4-dichlorobenzylimidazole derivatives having a phenylpyrrole moiety (related to the antibiotic pyrrolnitrin) in the alpha-position are reported. A number of substituents on the phenyl ring, ranging from hydrophobic (tert-butyl, phenyl, or 1-pyrrolyl moiety) to basic (NH(2)), polar (CF(3), CN, SCH(3), NO(2)), or hydrogen bond donors and acceptor (OH) groups, were chosen to better understand the interaction of these compounds with cytochrome P450 14-alpha-lanosterol demethylase (P450(14DM)). Finally, the triazole counterpart of one of the imidazole compounds was synthesized and tested to investigate influence of the heterocyclic ring on biological activity. The in vitro antifungal activities of the newly synthesized azoles 10p-v,x-c' were tested against Candida albicans and Candida spp. at pH 7.2 and pH 5.6. A CoMFA model, previously derived for a series of antifungal agents belonging to chemically diverse families related to bifonazole, was applied to the new products. Because the results produced by this approach were not encouraging, Catalyst software was chosen to perform a new 3D-QSAR study. Catalyst was preferred this time because of the possibility of considering each compound as a collection of energetically reasonable conformations and of considering alternative stereoisomers. The pharmacophore model developed by Catalyst, named HYPO1, showed good performances in predicting the biological activity data, although it did not exhibit an unequivocal preference for one enantiomeric series of inhibitors relative to the other. One aromatic nitrogen with a lone pair in the ring plane (mapped by all of the considered compounds) and three aromatic ring features were recognized to have pharmacophoric relevance, whereas neither hydrogen bond acceptor nor hydrophobic features were found. These findings confirmed that the key interaction of azole antifungals with the demethylase enzyme is the coordination bond to the iron ion of the porphyrin system, while interactions with amino acids localized in proximity of heme could modulate the biological activity of diverse antifungal agents. In conclusion, HYPO1 conveys important information in an intuitive manner and can provide predictive capability for evaluating new compounds.

Antifungal Agents↗
PubMed2005

Pseudotrienic acids A and B, two bioactive metabolites from Pseudomonas sp. MF381-IODS.

Bioassay-guided fractionation of the liquid culture broth of Pseudomonas sp. MF381-IODS yielded two new antimicrobial substances, identified as (2E,4E,6E)-9-[((2S,3R)-3-hydroxy-4-{[(3E,5E,7RS)-7-hydroxy-4-methylhexadeca-3,5-dienoyl]amino}-2-methylbutanoyl)amino]nona-2,4,6-trienoic acid and the tetradeca equivalent, named pseudotrienic acids A (1) and B (2), respectively. The compounds are prone to lactone formation, and their structures suggest them to be derived from ring opening of a macrolide. Pseudotrienic acids A and B inhibited growth of Staphylococcus aureus (MIC 70 microg/mL) and Pseudomonas syringae pv. syringae (MIC 70 microg/mL). Two known antimicrobial compounds, the polyketide 2,3-deepoxy-2,3-didehydrorhizoxin (3) and the tryptophan-derived pyrrolnitrin (4), were also identified.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Tryptophan 7-halogenase from Pseudomonas aureofaciens ACN strain: gene cloning and sequencing and the enzyme expression].

The gene of tryptophan 7-halogenase was isolated from the Pseudomonas aureofaciens ACN strain producing pyrrolnitrin, a chlorocontaining antibiotic, and sequenced. A high homology degree (over 95%) was established for the genes and the corresponding halogenases from P. aureofaciens ACN and P. fluorescens BL915. The tryptophan 7-halogenase gene was amplified by PCR, and the corresponding enzyme was expressed in Escherichia coli cells using the pBSII SK+ vector.

Amino Acid Sequence↗
PubMed2003

The biosynthesis of shikimate metabolites.

This review covers the literature published during 2000 on the biosynthesis of compounds derived wholly or partly from intermediates on the shikimate pathway. Recent developments in the enzymology and genetics of the shikimate pathway arc also described. Enzymes involved in the biogenetic pathway to the aromatic amino acids are covered initially followed by sections dedicated to metabolites derived in some part from intermediates on the pathway. These include pyrrolnitrin. violacein. indole-3-acetic acid, coumarins, lignans, lignin, tannins, melanin, flavanoids, ubiquinone, TOPA quinone, PQQ, and tropanes.

Amino Acids↗
PubMedDate not supplied

Global regulation of expression of antifungal factors by a Pseudomonas fluorescens biological control strain.

The root-colonizing bacterium Pseudomonas fluorescens BL915 protects a variety of seedlings from damping-off disease caused by the fungal pathogen Rhizoctonia solani. Spontaneous pleiotropic mutants of P. fluorescens strain BL915 which fail to synthesize antifungal factors such as chitinase, cyanide, and pyrrolnitrin and exhibit altered colony morphology were isolated. Such mutants fail to inhibit the growth of R. solani in vitro, and their biological control capability is sharply reduced. We characterized a genomic DNA fragment from strain BL915 which, when introduced into these pleiotropic mutants, restored the lost functions, the wild-type colony morphology, and bio-control activity. DNA sequence analysis of the genomic fragment revealed the presence of genes homologous to those of numerous bacterial global regulatory systems and identified a cluster of genes identical in organization to the Escherichia coli gene cluster consisting of uvrY, uvrC, pgsA, and glyW. Coordinate biosynthesis of multiple antifungal products in some heterologous Pseudomonas strains in response to the introduction of the strain BL915 genomic fragment confirmed the regulatory nature of sequences contained on this fragment. Further genetic analysis indicated a gene homologous to response regulators of bacterial two-component systems was sufficient to complement the pleiotropic mutants and to activate antifungal genes in heterologous strains. Marker exchange of a truncated version of this gene into the P. fluorescens BL915 chromosome generated pleiotropic mutants indistinguishable from the original spontaneous mutants. Cloning and sequencing of the response regulator gene from several spontaneous mutants allowed identification of various nucleotide changes associated with the gene in such mutants.

Amino Acid Sequence↗
PubMed1980

Regulation of phospho-2-keto-3-deoxy-heptonate aldolase (DAHP synthase) and anthranilate synthase of Pseudomonas aureofaciens.

Phospho-2-keto-3-deoxy-heptonate aldolase (DAHP synthase) of Pseudomonas aureofaciens ATCC 15926 was inhibited by L-tyrosine. The inhibition was competitive with erythrose 4-phosphate as the varied substrate but non-competitive with respect to phosphoenolpyruvate. Anthranilate synthase was inhibited by L-tryptophan. The inhibition was competitive with respect to chorismate but non-competitive with L-glutamine or NH4+ as the varied substrate. DAHP synthase and anthranilate synthase were not repressed when aromatic amino acids were included in the growth medium. In bacteria grown in the presence of L-phenylalanine, the anthranilate synthase activity was enhanced about threefold compared with the control. Similar results were obtained with the mutant strain P. aureofaciens ACN, which produces increased amounts of pyrrolnitrin.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed2004

PCR-based identification and characterization of Burkholderia cepacia complex bacteria from clinical and environmental sources.

AIMS: To study the genotypic identification and characterization of the 119 Burkholderia cepacia complex (Bcc) strains recovered from clinical and environmental sources in Japan and Thailand. METHODS AND RESULTS: Based on the results of analysis by 16S rDNA RFLP generated after digestion with DdeI, the Bcc strains were differentiated into two patterns: pattern 1 (including Burkholderia vietnamiensis) and pattern 2 (including B. cepacia genomovar I, Burkholderia cenocepacia and Burkholderia stabilis). All strains belonged to pattern 2 except for one strain. In the RFLP analysis of the recA gene using HaeIII, strains were separated into eight patterns designated as A, D, E, G, H, I, J and K, of which pattern K was new. Burkholderia cepacia epidemic strain marker (BCESM) encoded by esmR [corrected] and the pyrrolnitrin biosynthetic locus encoded by prnC were present in 22 strains (18%) and 88 strains (74%) from all sources, respectively. All esmR-positive [corrected] strains belonged to B. cenocepacia, whereas most prnC-positive strains belonged to B. cepacia genomovar I. CONCLUSIONS: Strains derived from clinical sources were assigned to B. cepacia genomovar I, B. cenocepacia, B. stabilis and B. vietnamiensis. The majority of Bcc strains from environmental sources (77 of a total 95 strains) belonged to B. cepacia genomovar I, whereas the rest belonged to B. cenocepacia. On the basis of genomovar-specific PCR and prnC RFLP analysis, strains belonging to recA pattern K were identified as B. cepacia genomovar I. SIGNIFICANCE AND IMPACT OF THE STUDY: This work provides the genotypic identification of a collection of the Bcc strains from Japan and Thailand. RFLP analysis of the prnC gene promises to be a useful method for differentiating Burkholderia pyrrocinia from B. cepacia genomovar I strains.

Burkholderia Infections↗
PubMed1983

Contact dermatitis due to honeybee royal jelly.

A woman who had ingested honeybee royal jelly as a nutrient, showed an exacerbation of dermatitis when it was applied to her feet. A topical fungicide also aggravated her skin lesions. Patch testing showed positive reactions to the royal jelly, pyrrolnitrin in the fungicide and urushiol. Positive reactions to the royal jelly were found in 2 out of 10 controls, 1 of whom was sensitive to propolis.

Adult↗
PubMed1987

Rhizobacteria of maize and their antifungal activities.

During the growing season of 1984, the rhizobacteria (including organisms from the rhizosphere soil, the rhizoplane, and internal root zones) of 47 maize plants (two varieties) sampled from different locations in France and at different growth stages were inventoried. Isolates were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of their total cell proteins and were found to represent 352 different protein electrotypes. Maize seedlings were initially colonized by a small number of different strains. Densities reached up to 10 CFU/g of root. Later in the season, the population density decreased but the heterogeneity of the rhizobacterial populations increased. Fluorescent pseudomonads represented up to 35% of the total rhizobacterial population and comprised 43 different electrotypes. Other bacteria regularly present were Xanthomonas maltophilia, Serratia liquefaciens, Pseudomonas paucimobilis, and Bacillus spp. There was a very low similarity between rhizobacterial populations of plants of the same cultivar (LG5) within one field at different growth stages and also between rhizobacterial populations of the cultivars LG5 and BRIO42 on the same field. Most electrotypes (76%) were found on a single occasion. None of the 352 electrotypes was present on all plants. In the 1985 analysis the rhizobacteria of maize seedlings (one variety) sampled from one field were characterized. They represented 236 different protein electrotypes. Thirty-three isolates showed antifungal activity against major maize pathogens; they comprised four Pseudomonas cepacia strains, producing pyrrolnitrin as well as another unknown antifungal compound.

Journal Article↗
PubMed1992

Pseudomonas cepacia suppression of sunflower wilt fungus and role of antifungal compounds in controlling the disease.

In a field experiment, Pseudomonas cepacia J82rif and J51rif increased sunflower emergence in the presence of the fungus Sclerotinia sclerotiorum. Pyrrolnitrin, aminopyrrolnitrin, and monochloroaminopyrrolnitrin were isolated from J82 and identified by using thin-layer chromatography, high-performance liquid chromatography, and electron impact-mass, UV, and infrared spectroscopy. In growth chamber experiments, two antibiosis-negative mutants were not different from the parent strain in protecting the seeds from the fungus.

Antifungal Agents↗
PubMed1994

Cloning of a phenazine biosynthetic locus of Pseudomonas aureofaciens PGS12 and analysis of its expression in vitro with the ice nucleation reporter gene.

Pseudomonas aureofaciens PGS12 produces three phenazine antibiotics, in addition to siderophores, hydrogen cyanide, pyrrolnitrin, and indoleacetic acid. Tn5-259.7 transposon mutagenesis was carried out to identify and clone a chromosomal locus involved in phenazine biosynthesis. Three classes of mutants were obtained: mutants deficient in phenazine production (Phz-), mutants deficient in hydrogen cyanide production (HCN-), and mutants deficient in the production of both compounds. EcoRI DNA fragments that contained the transposon and flanking regions were cloned from three mutants with single-transposon insertions, one from each phenotypic class. Phenazine and hydrogen cyanide production was restored by complementation of Phz- or HCN- mutants with selected cosmids from a PGS12 genomic library. No cosmids that complemented the doubly deficient Phz-HCN- mutant were obtained. A promoterless ice nucleation reporter gene was inserted in a phenazine biosynthetic locus by Tn3-spice transposon mutagenesis of a cosmid which complemented a phenazine-minus mutant. Reporter gene fusions that expressed the ice nucleation phenotype and no longer complemented phenazine production were introduced into the PGS12 chromosome by marker exchange. The expression of this locus was then monitored under different culture conditions. Expression decreased at pH levels below 7, and it was not affected by iron. Shikimic acid and phenylalanine favored higher expression levels. Expression was reduced in media with low substrate concentrations, indicating the importance of nutrient availability.

Bacterial Outer Membrane Proteins↗
PubMed2000

Controlling instability in gacS-gacA regulatory genes during inoculant production of Pseudomonas fluorescens biocontrol strains.

Secondary metabolism in fluorescent pseudomonads is globally regulated by gacS, which encodes a membrane-bound sensor kinase, and gacA, which encodes a transcriptional response regulator. Spontaneous mutation in either gene blocked biosynthesis of the antimicrobial compounds hydrogen cyanide, 2,4-diacetylphloroglucinol, pyoluteorin, and pyrrolnitrin by the model biocontrol strain Pseudomonas fluorescens CHA0. Spontaneous mutants also had altered abilities to utilize several carbon sources and to increase medium pH compared with the wild type, suggesting that gacS and gacA influence primary as well as secondary bacterial metabolism. Inoculant efficacy for biocontrol was significantly reduced by contamination with regulatory mutants which accumulated during inoculum production. Spontaneous mutants accumulated in all 192 separate liquid cultures examined, typically at a frequency of 1% or higher after 12 days. During scale-up in a simulated industrial fermentation process, mutants increased exponentially and accounted for 7, 23, and 61% of the total viable cells after transfer to 20-, 100-, and 500-ml preparations, respectively. GacS(-) and GacA(-) mutants had identical phenotypes and occurred at the same frequency, indicating that the selective pressures for the two mutants were similar. We developed a simple screening method for monitoring inoculant quality based on the distinctive appearance of mutant colonies (i.e., orange color, enlarged diameter, hyperfluorescence). Mutant competitiveness was favored in a nutrient-rich medium with a high electrolyte concentration (nutrient broth containing yeast extract). We were able to control mutant accumulation and to clean up contaminated cultures by using certain mineral amendments (i.e., zinc, copper, cobalt, manganese, and ammonium molybdate) or by diluting media 1/10. Spontaneous mutants and genetic constructs had the same response to culture conditions. Zinc and medium dilution were also effective for improving the genetic stability of other P. fluorescens biocontrol strains obtained from Ghana and Italy.

Bacterial Proteins↗