Search results for "Pseudomonas Fluorescens"
showing 10 items of 56 documents
Characterization and transcriptional analysis of Pseudomonas fluorescens denitrifying clusters containing the nar, nir, nor and nos genes
2001
In this study, we report the cloning and characterization of denitrifying gene clusters of Pseudomonas fluorescens C7R12 containing the narXLDKGHJI, nirPOQSM, norCB and nosRZDFYL genes. While consensus sequences for Fnr-like protein binding sites were identified in the promoter regions of the nar, nir, nor and nos genes, consensus sequences corresponding to the NarL binding sites were identified only upstream the nar genes. Monitoring by mRNA analysis the expression of the narG, nirS, norB and nosZ structural genes suggests a sequential induction of the denitrification system in P. fluorescens.
Relative involvement of nitrate and nitrite reduction in the competitiveness of Pseudomonas fluorescens in the rhizosphere of maize under non-limitin…
2002
Competition between different isogenic mutants of Pseudomonas fluorescens unable to carry out the first steps of the denitrification pathway was compared in soil micro-columns non-planted or planted with maize. A new isogenic mutant of P. fluorescens YT101 affected in both nitrate and nitrite respirations was constructed and used as a model of non-denitrifying strain (FM69MS strain). The outcome of the selection exerted by the plant after co-inoculation of FM69MS at the same ratio either with an isogenic denitrifier unable to reduce nitrate (Nar(-) mutant) or with an isogenic NO2 (-) accumulator (Nir(-) mutant) was investigated in non-limiting NO3 (-) conditions. Regardless of the inoculate…
Antimicrobial and Insecticidal: Cyclic Lipopeptides and Hydrogen Cyanide Produced by Plant-Beneficial Pseudomonas Strains CHA0, CMR12a, and PCL1391 C…
2017
Particular groups of plant-beneficial fluorescent pseudomonads are not only root colonizers that provide plant disease suppression, but in addition are able to infect and kill insect larvae. The mechanisms by which the bacteria manage to infest this alternative host, to overcome its immune system, and to ultimately kill the insect are still largely unknown. However, the investigation of the few virulence factors discovered so far, points to a highly multifactorial nature of insecticidal activity. Antimicrobial compounds produced by fluorescent pseudomonads are effective weapons against a vast diversity of organisms such as fungi, oomycetes, nematodes, and protozoa. Here, we investigated whe…
Fingerprinting and diversity of bacterial copA genes in response to soil types, soil organic status and copper contamination
2007
A molecular fingerprinting assay was developed to assess the diversity of copA genes, one of the genetic determinants involved in bacterial resistance to copper. Consensus primers of the copA genes were deduced from an alignment of sequences from proteobacterial strains. A PCR detection procedure was optimized for bacterial strains and allowed the description of a novel copA genetic determinant in Pseudomonas fluorescens. The copA DNA fingerprinting procedure was optimized for DNA directly extracted from soils differing in their physico-chemical characteristics and in their organic status (SOS). Particular copA genetic structures were obtained for each studied soil and a coinertia analysis …
Functional citric acid cycle in an arcA mutant of Escherichia coli during growth with nitrate under anoxic conditions
1998
The operation of the citric acid cycle of Escherichia coli during nitrate respiration (anoxic conditions) was studied by measuring end products and enzyme activities. Excretion of products other than CO2, such as acetate or ethanol, was taken as an indication for a non-functional cycle. From glycerol, approximately 0.3 mol acetate was produced; the residual portion was completely oxidized, indicating the presence of a partially active citric acid cycle. In an arcA mutant devoid of the transcriptional regulator ArcA, glycerol was completely oxidized with nitrate as an electron acceptor, demonstrating derepression and function of the complete pathway. Glucose, on the other hand, was excreted …
PERBANDINGAN DAYA HAMBAT BAKTERI Pseudomonas fluorescens ASAL TOMAT, KEDELAI, DAN JAGUNG TERHADAP Ralstonia solanacearum SECARA IN VITRO
2018
<em>Inhibition of Pseudomonas fluorescens isolates the origin of tomato, soybean and corn against Ralstonia solanacearum tested using a completely randomized design (CRD). P. fluorescens growth was measured at King's B medium by way of suspension antagonist put on filter paper of 0.5 cm in diameter. Inhibition of P. fluorescens is done by placing the antagonist suspension of 0.5 cm diameter filter paper on NA media that has been deployed R. solanacearum. The results showed that: (a) the growth of P. fluorescens origin of tomato, soybean and corn on King's B media were not significantly different, (b) the inhibition of P. fluorescens isolates against R. solanacearum not signific…
Encapsulation of the Bacillus thuringiensis secretable toxins Vip3Aa and Cry1Ia in Pseudomonas fluorescens
2013
Vip3A and Cry1I toxins are secreted during the vegetative growth of Bacillus thuringiensis. Vip3A toxins do not share homology to the crystal (Cry) proteins and are active against a different spectrum of lepidopteran species. Cry1I toxins share similarity with the Cry1 protein group but do not accumulate in the parasporal crystal. Since Vip3A and Cry1I toxins are released from the cell, they are excluded from biological formulates based on spores and crystals of B. thuringiensis. As an approach to obtain novel sprayable insecticides containing Vip3 or Cry1I toxins, Vip3Aa and Cry1Ia proteins were expressed in Pseudomonas fluorescens. This bacterium, non-pathogenic to animals or plants, can …
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…
Phytopathogenic Bacteria Associated with Bacterioses of Common Oak (Quercus robur L.) in Ukraine
2022
Studying the biological characteristics of the causative agents of bacteriosis of the common oak (Quercus robur L.) (to highlight the links between the key factors of pathogenesis and bacterial groups) is a new and relevant area of research. This work aims to identify the species composition of phytopathogenic bacteria associated with common oak bacteriosis and to study the morphological, cultural, and biochemical properties of pathogens. To establish the general phytosanitary state of the surveyed stands, classical forest inventory and phytopathological (visual on based on typical symptoms of the disease and macroscopic) methods were used. The properties of isolated bacteria were studied u…
Submicrometer-Sized Roughness Suppresses Bacteria Adhesion.
2020
Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for alternative strategies to prevent adhesion of bacteria to surfaces. Chemical modification of the surfaces by tethering of functional polymer brushes or films provides a route toward antifouling coatings. Furthermore, nanorough or superhydrophobic surfaces can delay biofilm formation. Here we show that submicrometer-sized roughness can outweigh surface chemistry by testing the adhesion of E. coli to surfaces of different topography and wettability over long exposure times (>7 days). Gram-negative and positive bacterial strains are tes…