Simply enhancing throughput of free-flow electrophoresis via organic-aqueous environment for purification of weak polarity solute of phenazine-1-carboxylic acid in fermentation of Pseudomonas sp. M18.

Herein, a simple novel free-flow electrophoresis (FFE) method was developed via introduction of organic solvent into the electrolyte system, increasing the solute solubility and throughput of the sample. As a proof of concept, phenazine-1-carboxylic acid (PCA) from Pseudomonas sp. M18 was selected as a model solute for the demonstration on feasibility of novel FFE method on account of its faint solubility in aqueous circumstance.

Quantitative investigation of resolution increase of free-flow electrophoresis via simple interval sample injection and separation.

Interval free-flow zone electrophoresis (FFZE) has been used to suppress sample band broadening greatly hindering the development of free-flow electrophoresis (FFE). However, there has been still no quantitative study on the resolution increase of interval FFZE. Herein, we tried to make a comparison between bandwidths in interval FFZE and continuous one.

Novel antiphytopathogenic compound 2-heptyl-5-hexylfuran-3-carboxylic acid, produced by newly isolated Pseudomonas sp. strain SJT25.

Pseudomonas sp. strain SJT25, which strongly antagonizes plant pathogens, was isolated from rice rhizosphere soil by a bioactivity-guided approach. A novel antiphytopathogenic compound was isolated from the fermentation broth of Pseudomonas sp.

Purification of low-concentration phenazine-1-carboxylic acid from fermentation broth of Pseudomonas sp. M18 via free flow electrophoresis with gratis gravity.

The low-concentration phenazine-1-carboxylic acid (PCA) ( = 0.3 mM) extracted from fermentation broth of Pseudomonas sp. M18 was selected to be purified with a newly facile free flow electrophoresis (FFE) device with gratis gravity.

Stacking and determination of phenazine-1-carboxylic acid with low pKa in soil via moving reaction boundary formed by alkaline and double acidic buffers in capillary electrophoresis.

As shown herein, a normal moving reaction boundary (MRB) formed by an alkaline buffer and a single acidic buffer had poor stacking to the new important plant growth promoter of phenazine-1-carboxylic acid (PCA) in soil due to the leak induced by its low pK(a). To stack the PCA with low pK(a) efficiently, a novel stacking system of MRB was developed, which was formed by an alkaline buffer and double acidic buffers (viz., acidic sample and blank buffers).

Medium optimization for phenazine-1-carboxylic acid production by a gacA qscR double mutant of Pseudomonas sp. M18 using response surface methodology.

Statistics based experimental designs were applied to optimize the culture medium components for enhancing phenazine-1-carboxylic acid (PCA) production by Pseudomonas sp. strain M18GQ, a gacA qscR double mutant of Pseudomonas sp. strain M18.

Rapid quantitative analysis of phenazine-1-carboxylic acid and 2-hydroxyphenazine from fermentation culture of Pseudomonas chlororaphis GP72 by capillary zone electrophoresis.

Natural phenazines in secondary metabolites of bacteria have been receiving increasing attention in recent years due to their potential usage as antibiotics. In the present study, a rapid and reliable capillary zone electrophoresis (CZE) method was developed and validated for monitoring for the first time dynamic phenazine-1-carboxylic acid (PCA) and the 2-hydroxyphenazine (2-OH-PHZ) production of Pseudomonas chlororaphis GP72 during the entire fermentation cycle. The paper begins with the optimization of separate conditions for 2-OH-PHZ and PCA together with phenazine (PHZ), which is used as internal standard.

Optimization of critical medium components using response surface methodology for phenazine-1-carboxylic acid production by Pseudomonas sp. M-18Q.

The optimal flask-shaking batch fermentation medium for phenazine-1-carboxylic acid (PCA) production by Pseudomonas sp. M-18Q, a qscR chromosomal inactivated mutant of the strain M18 was studied using statistical experimental design and analysis. The Plackett-Burman design (PBD) was used to evaluate the effects of eight medium components on the production of PCA, which showed that glucose and soytone were the most significant ingredients (P<0.

Las-like quorum-sensing system negatively regulates both pyoluteorin and phenazine-1-carboxylic acid production in Pseudomonas sp. M18.

A las-like quorum-sensing system in Pseudomonas sp. M18 was identified, which consisted of lasI and lasR genes encoding LuxI-LuxR type regulator. Several functions of the las system from strain M18 were investigated in this study.

Medium factor optimization and fermentation kinetics for phenazine-1-carboxylic acid production by Pseudomonas sp. M18G.

We investigated the production of biofungicide phenazine-1-carboxlic (PCA) by Pseudomonas sp. M18G, a gacA-deficient mutant of M18 for PCA high-production. Glucose was chosen as the optimal carbon source and soy peptone as the nitrogen source.

Isolation, identification, and degradation characteristics of phenazine-1-carboxylic acid-degrading strain Sphingomonas sp. DP58.

A phenazine-1-carboxylic acid (PCA)-degrading bacterium, strain DP58, was isolated from pimiento rhizosoil. Based on morphology, physiologic tests, 16S rDNA sequence, and phylogenetic characteristics, it was identified as Sphingomonas sp. The PCA-degradation experiments were conducted both in Luria-Bertani and inorganic salt medium at 28 degrees C.

LysR family factor PltR positively regulates Pyoluteorin production in a pathway-specific manner in Pseudomonas sp. M18.

The pltR gene, coding a putative LysR-type regulator, was identified upstream Plt biosynthetic gene cluster in Pseudomonas sp. M18 using bioinformatics technology. The null mutation of pltR resulted in mutant M18TRG (pltR::Gm) by recombination and its Plt (Pyoluteorin) production declined to 30% while PCA (Phenazine-1-carboxylic acid) production remained unchanged as compared with the wild-type M18 grown in King's Medium B.

Correlation between antifungal agent phenazine-1-carboxylic acid and pyoluteorin biosynthesis in Pseudomonas sp. M18.

Biosynthesis and secretion of two different types of antifungal compound [phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt) in Pseudomonas sp. M18] contribute to its suppression of soil-borne root pathogens. To better understand the correlation between two antifungal agents in secondary metabolism, a DNA fragment covering partial pltC and pltD coding sequences was obtained by screening the genomic library of Pseudomonas sp.

[Effects of sigma38 subunit deletion of RNA polymerase on antibiotics biosynthesis in pseudomonas].

With the designed primers, PCR was carried out using the genomic DNA of Pseudomonas sp. M18 as a template and a 378bp DNA fragment of the rpoS gene was amplified. Then, a 3.

Autoinduction of RpoS biosynthesis in the biocontrol strain Pseudomonas sp. M18.

The rpoS gene from Pseudomonas sp. M18, which encodes predicted protein (an alternative sigma factor s, sigma(S), or sigma(38)) with 99.5% sequence identity with RpoS from Pseudomonas aeruginosa PAO1, was first cloned.

[Construction and identification of rpoS gene inserted and fused in frame with the promoterless lacZ in Pseudomonas sp. M18].

With hybridization in situ and Southern blots, an Eco RI- Xho I DNA fragment of 3.1 kb in length containing an rpoS gene and its flanking sequence was first cloned into pBluescript SK to generate pBLS by screening the genomic DNA library of Pseudomonas sp. M18.

[Analysis of mechanism and relationship of GacA and RsmA, two regulators of antibiotics production in Pseudomonas sp. M18].

In previous study, it has already been confirmed that the wild type strain of Pseudomonas sp. M18 isolated from the agricultural soil can produce two antifungal agents phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt). Biosynthesis and secretion of these secondary metabolites contribute to its biological control and suppression of soilborne pathogenic fungi.

[Negative regulation on PCA production is not correlated with positive regulation on BHL and HHL synthesis by gacA in Pseudomonas sp. M18].

At least 5 kinds of N-acyl-homoserine lactones(AHLs) were identified in Pseudomonas sp. M18. They were: N-butyryl-L-homoserine lactone(C4-HSL, BHL), N-hexanoyl-L-homoserine lactone(C6-HSL, HHL), N-(3-oxohexanoyl)-L-homoserine lactone(3-Oxo-C6-HSL, OHHL), N-(3-oxooctanoyl)-L-homoserine lactone (3-Oxo-C8-HSL, OOHL) and N-(3-oxodecanoyl)-L-homoserine lactone(3-Oxo-C10-HSL, ODHL).

[Differential regulation of phenazine-1-carboxylic acid and pyoluteorin production mediated by inactivated gacA in Pseudomonas sp. M18].

Pseudomonas sp. M18 is one of the plant-growth-promoting rhizobacteria, which can produce fungicides: phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt). The chromosomally gacA inactivated mutant named M18G was constructed and its PCA production was enhanced 31-fold and Plt production was almost blocked completely in KMB medium.

[Transcriptional repression of pltZ on pyoluteorin ABC transporter of Pseudomonas sp. M18].

A pltZ gene involved in negatively regulating pyoluteorin (Plt) biosynthesis, and an ABC (ATP-binding cassette) transporter involved in pyoluteorin secretion and itself resistance, were identified downstream of Plt biosynthesis gene cluster in Pseudomonas sp. M18. The ABC transporter gene pltH'-lacZ translational and transcriptional fusion expression plasmids, pHZLF and pHZCF, were constructed using promoter probe vector pME6015 and pME6522 respectively, and then were introduced into the wild-type strain of Pseudomonas sp.

[Differential effect of temperature on Plt and PCA synthesis in a rsmA inactivated mutant strain of Pseudomonas sp. M-18].

Rsm (repressor of secondary metabolite) A is an mRNA binding protein which functions as a global repressor to control multiple genes at the posttranscriptional level. Using homologous recombination technique a chromosomal rsmA inactivated mutant strain M-18R was constructed in Pseudomonas sp. M-18, a strain of plant-growth-promoting rhizobacteria, which could inhibit several soilborn phytopathogens by producing secondary metabolites including phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt) in one single strain.