The Behavior of Bacteria Designed for Biodegradation

Ramos, Juan L.; Dı́az, Eduardo; Dowling, David N.; Lorenzo, Vı́ctor de; Molin, S; O’Gara, Fergal; Ramos, Cayo; Timmis, Kenneth N.

doi:10.1038/nbt1294-1349

Cited by 86 publications

(67 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One possibility would be to use the toxin of a given TA pair as a bactericidal or bacteriostatic compound. To achieve this, compounds that could disrupt the interactions between a toxin and its cognate antitoxin could be very useful as antibacterials: an unbalanced synthesis of each independent TAS triggers cell growth arrest or, for prolonged periods of time, cell death, with a survival rate of 1 ϫ 10 Ϫ6 to 10 Ϫ7 per each TA pair (127). Thus, it is conceivable that the employment of two independent toxins would potentiate such cell death, and indeed, TAS have been used in the design of tools for the biological containment of strains designed for bioremediation and other industrial purposes (87,123,127).…”

Section: Conclusion and Perspectives: Use Of Tas As Antimicrobialsmentioning

confidence: 99%

Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

Chan

Moreno-Córdoba

Yeo

et al. 2012

Microbiol Mol Biol Rev

127

View full text Add to dashboard Cite

SUMMARYPneumococcal infections cause up to 2 million deaths annually and raise a large economic burden and thus constitute an important threat to mankind. Because of the increase in the antibiotic resistance ofStreptococcus pneumoniaeclinical isolates, there is an urgent need to find new antimicrobial approaches to triumph over pneumococcal infections. Toxin-antitoxin (TA) systems (TAS), which are present in most living bacteria but not in eukaryotes, have been proposed as an effective strategy to combat bacterial infections. Type II TAS comprise a stable toxin and a labile antitoxin that form an innocuous TA complex under normal conditions. Under stress conditions, TA synthesis will be triggered, resulting in the degradation of the labile antitoxin and the release of the toxin protein, which would poison the host cells. The three functional chromosomal TAS fromS. pneumoniaethat have been studied as well as their molecular characteristics are discussed in detail in this review. Furthermore, a meticulous bioinformatics search has been performed for 48 pneumococcal genomes that are found in public databases, and more putative TAS, homologous to well-characterized ones, have been revealed. Strikingly, several unusual putative TAS, in terms of components and genetic organizations previously not envisaged, have been discovered and are further discussed. Previously, we reported a novel finding in which a unique pneumococcal DNA signature, the BOX element, affected the regulation of the pneumococcalyefM-yoeBTAS. This BOX element has also been found in some of the other pneumococcal TAS. In this review, we also discuss possible relationships between some of the pneumococcal TAS with pathogenicity, competence, biofilm formation, persistence, and an interesting phenomenon called bistability.

show abstract

Section: Conclusion and Perspectives: Use Of Tas As Antimicrobialsmentioning

confidence: 99%

Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

Chan

Moreno-Córdoba

Yeo

et al. 2012

Microbiol Mol Biol Rev

127

View full text Add to dashboard Cite

show abstract

“…Soil bacteria belonging to the species Pseudomonas fluorescens and Pseudomonas putida show metabolic versatility and a variety of characteristics that makes them attractive for environmental and agricultural uses (26). They can colonize the surface of plant roots and the surrounding soil regions (rhizosphere) in a mutualistic association in which the bacteria obtain nutrients from root exudates.…”

mentioning

confidence: 99%

Genetic Analysis of Functions Involved in Adhesion of Pseudomonas putida to Seeds

2000

View full text Add to dashboard Cite

Many agricultural uses of bacteria require the establishment of efficient bacterial populations in the rhizosphere, for which colonization of plant seeds often constitutes a critical first step. Pseudomonas putida KT2440 is a strain that colonizes the rhizosphere of a number of agronomically important plants at high population densities. To identify the functions involved in initial seed colonization by P. putida KT2440, we subjected this strain to transposon mutagenesis and screened for mutants defective in attachment to corn seeds. Eight different mutants were isolated and characterized. While all of them showed reduced attachment to seeds, only two had strong defects in their adhesion to abiotic surfaces (glass and different plastics). Sequences of the loci affected in all eight mutants were obtained. None of the isolated genes had previously been described in P. putida, although four of them showed clear similarities with genes of known functions in other organisms. They corresponded to putative surface and membrane proteins, including a calcium-binding protein, a hemolysin, a peptide transporter, and a potential multidrug efflux pump. One other showed limited similarities with surface proteins, while the remaining three presented no obvious similarities with known genes, indicating that this study has disclosed novel functions.Soil bacteria belonging to the species Pseudomonas fluorescens and Pseudomonas putida show metabolic versatility and a variety of characteristics that makes them attractive for environmental and agricultural uses (26). They can colonize the surface of plant roots and the surrounding soil regions (rhizosphere) in a mutualistic association in which the bacteria obtain nutrients from root exudates. In turn, some bacterial strains can promote plant growth and have biocontrol potential against certain pathogens (39). Also, some P. putida strains have the ability to degrade toxic organic compounds, which are frequently present as contaminants in the environment (26). P. putida KT2440, a derivative of the soil isolate mt-2 which has been widely studied in relation to biodegradation processes (17,21,28), can also colonize the rhizosphere of agronomically relevant plants at high population densities, making it a suitable candidate for its use in rhizoremediation (20).Agricultural uses of microorganisms often involve coating seeds with bacterial suspensions. Adhesion to the seed appears as a key element, since it determines the subsequent colonization of the root system. Establishment of the bacterial population in the root and colonization of the rhizosphere are essential for biocontrol efficiency (8). These latter events, root colonization and survival in the rhizosphere, as well as responses to root exudates, are being extensively studied at the molecular level (5,25,30,32,33), but very little is known regarding the elements that are important for bacterial colonization of seeds. Results obtained by DeFlaun and coworkers have shown that some P. fluorescens mutants defective in attachment to ...

show abstract

“…It has an extremely long biological half-life (>20 years), is one of the 126 priority contaminants declared by the US-EPA, stands seventh among the top 20 toxins, and is classified as a probable human carcinogen (Ramos et al, 1994;Yang et al, 2004). Metal-polluted land is not suitable for the cultivation of food or feed crops, and such soils require remediation to reduce the hazardous risk.…”

Section: Introductionmentioning

confidence: 99%

Isolation and engineering of plant growth promoting rhizobacteria <i>Pseudomonas aeruginosa</i> for enhanced cadmium bioremediation

Huang¹,

Liu²,

et al. 2016

J. Gen. Appl. Microbiol.

View full text Add to dashboard Cite

Although many bacteria are tolerant to heavy metals and play important roles in the immobilization of heavy metals, they cannot always be dependably reproduced under field conditions. In this work, a cadmium (Cd)-resistant bacterium was isolated from a Cd-contaminated oil field and identified as Pseudomonas aeruginosa (Pse-w). We then determined various plant growth promoting features such as the solubilization of phosphate, and the production of indole-3-acetic acid and siderophores. Lastly, we engineered the strain Psew-MT by targeting metallothioneins to the cell surface of Pse-w to immobilize Cd 2+ and promote plant growth. Our data revealed that Pse-w exhibited high levels of resistance to Cd 2+ (4 mM) and showed various plant growth promoting features. The engineered strain Pse-w-MT was found to adsorb Cd 2+ mainly via extracellular deposition, and had an enhanced ability for immobilizing Cd 2+ ions from the external media. Furthermore, the inoculation of Cd-polluted soil with Pse-w-MT significantly elevated the shoot and root biomass and leaf chlorophyll content. Similarly, plants inoculated with Psew-MT demonstrated markedly lower Cd 2+ accumulation in the root and shoot system. It was concluded that plant growth promoting rhizobacteria with a high Cd 2+ tolerance was an ideal candidate to be engineered for bioremediation and plant growth promotion against Cd-induced stress.

show abstract

The Behavior of Bacteria Designed for Biodegradation

Cited by 86 publications

References 52 publications

Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

Genetic Analysis of Functions Involved in Adhesion of Pseudomonas putida to Seeds

Isolation and engineering of plant growth promoting rhizobacteria <i>Pseudomonas aeruginosa</i> for enhanced cadmium bioremediation

Contact Info

Product

Resources

About