scholarly journals Pumping iron to keep fit: modulation of siderophore secretion helps efficient aromatic utilization in Pseudomonas putida KT2440

Microbiology ◽  
2014 ◽  
Vol 160 (7) ◽  
pp. 1393-1400 ◽  
Author(s):  
Hiren Joshi ◽  
Rachna Dave ◽  
V. P. Venugopalan
Keyword(s):  
Pseudomonas Putida ◽  
Compensatory Mechanism ◽  
Limited Information ◽  
Pseudomonas Putida Kt2440 ◽  
Physiological Factors ◽  
Aromatic Substrates ◽  
Iron Assimilation ◽  
Key Factor ◽  
Alternative Carbon Source

Studies of biotechnology applications of Pseudomonas putida KT2440 have been predominantly focused on regulation and expression of the toluene degradation (TOL) pathway. Unfortunately, there is limited information on the role of other physiological factors influencing aromatic utilization. In this report, we demonstrate that P. putida KT2440 increases its siderophore secretion in response to the availability of benzyl alcohol, a model aromatic substrate. It is argued that accelerated siderophore secretion in response to aromatic substrates provides an iron ‘boost’ which is required for the effective functioning of the iron-dependent oxygenases responsible for ring opening. Direct evidence for the cardinal role of siderophores in aromatic utilization is provided by evaluation of per capita siderophore secretion and comparative growth assessments of wild-type and siderophore-negative mutant strains grown on an alternative carbon source. Accelerated siderophore secretion can be viewed as a compensatory mechanism in P. putida in the context of its inability to secrete more than one type of siderophore (pyoverdine) or to utilize heterologous siderophores. Stimulated siderophore secretion might be a key factor in successful integration and proliferation of this organism as a bio-augmentation agent for aromatic degradation. It not only facilitates efficient aromatic utilization, but also provides better opportunities for iron assimilation amongst diverse microbial communities, thereby ensuring better survival and proliferation.

scholarly journals Involvement of MexS and MexEF-OprN in Resistance to Toxic Ion Chelators in Pseudomonas putida KT2440

2020 ◽  
Vol 8 (11) ◽  
pp. 1782
Author(s):  
Tania Henriquez ◽  
Tom Baldow ◽  
Yat Kei Lo ◽  
Dina Weydert ◽  
Andreas Brachmann ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Efflux Pump ◽  
Toxic Metal ◽  
Growth Defect ◽  
Metal Chelators ◽  
Pseudomonas Putida Kt2440 ◽  
Pseudomonas Species ◽  
Resistance Nodulation Division ◽  
Rnd Efflux Pump

Bacteria must be able to cope with harsh environments to survive. In Gram-negative bacteria like Pseudomonas species, resistance-nodulation-division (RND) transporters contribute to this task by pumping toxic compounds out of cells. Previously, we found that the RND system TtgABC of Pseudomonas putida KT2440 confers resistance to toxic metal chelators of the bipyridyl group. Here, we report that the incubation of a ttgB mutant in medium containing 2,2’-bipyridyl generated revertant strains able to grow in the presence of this compound. This trait was related to alterations in the pp_2827 locus (homolog of mexS in Pseudomonas aeruginosa). The deletion and complementation of pp_2827 confirmed the importance of the locus for the revertant phenotype. Furthermore, alteration in the pp_2827 locus stimulated expression of the mexEF-oprN operon encoding an RND efflux pump. Deletion and complementation of mexF confirmed that the latter system can compensate the growth defect of the ttgB mutant in the presence of 2,2’-bipyridyl. To our knowledge, this is the first report on a role of pp_2827 (mexS) in the regulation of mexEF-oprN in P. putida KT2440. The results expand the information about the significance of MexEF-OprN in the stress response of P. putida KT2440 and the mechanisms for coping with bipyridyl toxicity.

scholarly journals Metabolic role of aldehyde dehydrogenases in Pseudomonas putida KT2440

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Adriana Julián-Sánchez ◽  
Adeli P. Castrejón-Gonzaga ◽  
Gabriel Moreno-Hagelsieb ◽  
Rosario A. Muñoz-Clares ◽  
Héctor Riveros-Rosas
Keyword(s):  
Pseudomonas Putida ◽  
Pseudomonas Putida Kt2440 ◽  
Aldehyde Dehydrogenases ◽  
Metabolic Role

scholarly journals Hydroxyectoine Is Superior to Trehalose for Anhydrobiotic Engineering of Pseudomonas putida KT2440

2002 ◽  
Vol 68 (9) ◽  
pp. 4328-4333 ◽  
Author(s):  
M. Manzanera ◽  
A. García de Castro ◽  
A. Tøndervik ◽  
M. Rayner-Brandes ◽  
A. R. Strøm ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Desiccation Tolerance ◽  
Poor Survival ◽  
Pseudomonas Putida Kt2440 ◽  
Gram Negative ◽  
High Osmolarity ◽  
Considerable Potential ◽  
Key Factor ◽  
High Concentrations ◽  
Full Protection

ABSTRACT Anhydrobiotic engineering aims to increase the level of desiccation tolerance in sensitive organisms to that observed in true anhydrobiotes. In addition to a suitable extracellular drying excipient, a key factor for anhydrobiotic engineering of gram-negative enterobacteria seems to be the generation of high intracellular concentrations of the nonreducing disaccharide trehalose, which can be achieved by osmotic induction. In the soil bacterium Pseudomonas putida KT2440, however, only limited amounts of trehalose are naturally accumulated in defined high-osmolarity medium, correlating with relatively poor survival of desiccated cultures. Based on the enterobacterial model, it was proposed that increasing intracellular trehalose concentration in P. putida KT2440 should improve survival. Using genetic engineering techniques, intracellular trehalose concentrations were obtained which were similar to or greater than those in enterobacteria, but this did not translate into improved desiccation tolerance. Therefore, at least for some populations of microorganisms, trehalose does not appear to provide full protection against desiccation damage, even when present at high concentrations both inside and outside the cell. For P. putida KT2440, it was shown that this was not due to a natural limit in desiccation tolerance since successful anhydrobiotic engineering was achieved by use of a different drying excipient, hydroxyectoine, with osmotically preconditioned bacteria for which 40 to 60% viability was maintained over extended periods (up to 42 days) in the dry state. Hydroxyectoine therefore has considerable potential for the improvement of desiccation tolerance in sensitive microorganisms, particularly for those recalcitrant to trehalose.

Role of iron and the TonB system in colonization of corn seeds and roots by Pseudomonas putida KT2440

2005 ◽  
Vol 7 (3) ◽  
pp. 443-449 ◽  
Author(s):  
Maria Antonia Molina ◽  
Patricia Godoy ◽  
Maria Isabel Ramos-Gonzalez ◽  
Nuria Munoz ◽  
Juan L. Ramos ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Pseudomonas Putida Kt2440 ◽  
Tonb System

scholarly journals Intracellular 2-keto-3-deoxy-6-phosphogluconate is the signal for carbon catabolite repression of phenylacetic acid metabolism in Pseudomonas putida KT2440

Microbiology ◽  
2009 ◽  
Vol 155 (7) ◽  
pp. 2420-2428 ◽  
Author(s):  
Juhyun Kim ◽  
Jinki Yeom ◽  
Che Ok Jeon ◽  
Woojun Park
Keyword(s):  
Pseudomonas Putida ◽  
Transcriptional Repression ◽  
Catabolite Repression ◽  
Phenylacetic Acid ◽  
Carbon Catabolite Repression ◽  
Transcriptional Level ◽  
Pseudomonas Putida Kt2440 ◽  
Coa Ligase ◽  
Additional Support

The growth pattern of Pseudomonas putida KT2440 in the presence of glucose and phenylacetic acid (PAA), where the sugar is used in preference to the aromatic compound, suggests that there is carbon catabolite repression (CCR) of PAA metabolism by glucose or gluconate. Furthermore, CCR is regulated at the transcriptional level. However, this CCR phenomenon does not occur in PAA-amended minimal medium containing fructose, pyruvate or succinate. We previously identified 2-keto-3-deoxy-6-phosphogluconate (KDPG) as an inducer of glucose metabolism, and this has led to this investigation into the role of KDPG as a signal compound for CCR. Two mutant strains, the edd mutant (non-KDPG producer) and the eda mutant (KDPG overproducer), grew in the presence of PAA but not in the presence of glucose. The edd mutant utilized PAA even in the presence of glucose, indicating that CCR had been abolished. This observation has additional support from the finding that there is high phenylacetyl-CoA ligase activity in the edd mutant, even in the presence of glucose+PAA, but not in wild-type cells under the same conditions. Unlike the edd mutant, the eda mutant did not grow in the presence of glucose+PAA. Interestingly, there was no uptake and/or metabolism of PAA in the eda mutant cells under the same conditions. Targeted disruption of PaaX, a repressor of the PAA operon, had no effect on CCR of PAA metabolism in the presence of glucose, suggesting that there is another transcriptional repression system associated with the KDPG signal. This is the first study to demonstrate that KDPG is the true CCR signal of PAA metabolism in P. putida KT2440.

Plant growth promotion by Pseudomonas putida KT2440 under saline stress: role of eptA

2020 ◽  
Vol 104 (10) ◽  
pp. 4577-4592 ◽  
Author(s):  
Stefanie B. Costa-Gutierrez ◽  
María Jesús Lami ◽  
María Carolina Caram-Di Santo ◽  
Ana M. Zenoff ◽  
Paula A. Vincent ◽  
...  
Keyword(s):  
Plant Growth ◽  
Pseudomonas Putida ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Saline Stress ◽  
Pseudomonas Putida Kt2440

Juvenile xanthogranuloma of the subdural spaces mimicking chronic hematoma with positive FDG uptake on PET: case report

2020 ◽  
Vol 26 (4) ◽  
pp. 449-453
Author(s):  
Jacob A. Kahn ◽  
Jeffrey T. Waltz ◽  
Ramin M. Eskandari ◽  
Cynthia T. Welsh ◽  
Michael U. Antonucci
Keyword(s):  
Potential Role ◽  
Response To Treatment ◽  
Juvenile Xanthogranuloma ◽  
Imaging Features ◽  
Limited Information ◽  
Advanced Imaging ◽  
Systemic Involvement ◽  
The Central Nervous System ◽  
Infancy And Early Childhood

The authors report an unusual presentation of juvenile xanthogranuloma (JXG), a non–Langerhans cell histiocytosis of infancy and early childhood. This entity typically presents as a cutaneous head or neck nodule but can manifest with more systemic involvement including in the central nervous system. However, currently there is limited information regarding specific imaging features differentiating JXG from other neuropathological entities, with diagnosis typically made only after tissue sampling. The authors reviewed the initial images of a young patient with shunt-treated hydrocephalus and enlarging, chronic, extraaxial processes presumed to reflect subdural collections from overshunting, and they examine the operative discovery of a mass lesion that was pathologically proven to be JXG. Their results incorporate the important associated histological and advanced imaging features, including previously unreported metabolic activity on FDG PET. Ultimately, the case underscores the need to consider JXG in differential diagnoses of pediatric intracranial masses and highlights the potential role of PET in the initial diagnosis and response to treatment.

Let-7e-5p Regulates GLP-1 Content and Basal Release From Enteroendocrine L Cells From DIO Male Mice

Endocrinology ◽  
2019 ◽  
Vol 161 (2) ◽  
Author(s):  
Sandra Handgraaf ◽  
Rodolphe Dusaulcy ◽  
Florian Visentin ◽  
Jacques Philippe ◽  
Yvan Gosmain
Keyword(s):  
Compensatory Mechanism ◽  
L Cells ◽  
Low Fat Diet ◽  
Obesity And Diabetes ◽  
Basal Release ◽  
Glucagon Like Peptide 1 ◽  
Cell Transcriptome ◽  
Microarray Analyses

Abstract Characterization of enteroendocrine L cells in diabetes is critical for better understanding of the role of glucagon-like peptide-1 (GLP-1) in physiology and diabetes. We studied L-cell transcriptome changes including microRNA (miRNA) dysregulation in obesity and diabetes. We evaluated the regulation of miRNAs through microarray analyses on sorted enteroendocrine L cells from control and obese glucose-intolerant (I-HFD) and hyperglycemic (H-HFD) mice after 16 weeks of respectively low-fat diet (LFD) or high-fat diet (HFD) feeding. The identified altered miRNAs were studied in vitro using the mouse GLUTag cell line to investigate their regulation and potential biological functions. We identified that let-7e-5p, miR-126a-3p, and miR-125a-5p were differentially regulated in L cells of obese HFD mice compared with control LFD mice. While downregulation of let-7e-5p expression was observed in both I-HFD and H-HFD mice, levels of miR-126a-3p increased and of miR-125a-5p decreased significantly only in I-HFD mice compared with controls. Using miRNA inhibitors and mimics we observed that modulation of let-7e-5p expression affected specifically GLP-1 cellular content and basal release, whereas Gcg gene expression and acute GLP-1 secretion and cell proliferation were not affected. In addition, palmitate treatment resulted in a decrease of let-7e-5p expression along with an increase in GLP-1 content and release, suggesting that palmitate acts on GLP-1 through let-7e-5p. By contrast, modulation of miR-125a-5p and miR-126a-3p in the same conditions did not affect content or secretion of GLP-1. We conclude that decrease of let-7e-5p expression in response to palmitate may constitute a compensatory mechanism contributing to maintaining constant glycemia in obese mice.

scholarly journals Protective Role of Glutathione in the Hippocampus after Brain Ischemia

2021 ◽  
Vol 22 (15) ◽  
pp. 7765
Author(s):  
Youichirou Higashi ◽  
Takaaki Aratake ◽  
Takahiro Shimizu ◽  
Shogo Shimizu ◽  
Motoaki Saito
Keyword(s):  
Oxidative Stress ◽  
Neuronal Death ◽  
Excitatory Amino Acid ◽  
Ischemia Reperfusion ◽  
Thiol Group ◽  
Protective Role ◽  
Key Factor ◽  
Rate Limiting ◽  
Cysteine Uptake

Stroke is a major cause of death worldwide, leading to serious disability. Post-ischemic injury, especially in the cerebral ischemia-prone hippocampus, is a serious problem, as it contributes to vascular dementia. Many studies have shown that in the hippocampus, ischemia/reperfusion induces neuronal death through oxidative stress and neuronal zinc (Zn2+) dyshomeostasis. Glutathione (GSH) plays an important role in protecting neurons against oxidative stress as a major intracellular antioxidant. In addition, the thiol group of GSH can function as a principal Zn2+ chelator for the maintenance of Zn2+ homeostasis in neurons. These lines of evidence suggest that neuronal GSH levels could be a key factor in post-stroke neuronal survival. In neurons, excitatory amino acid carrier 1 (EAAC1) is involved in the influx of cysteine, and intracellular cysteine is the rate-limiting substrate for the synthesis of GSH. Recently, several studies have indicated that cysteine uptake through EAAC1 suppresses ischemia-induced neuronal death via the promotion of hippocampal GSH synthesis in ischemic animal models. In this article, we aimed to review and describe the role of GSH in hippocampal neuroprotection after ischemia/reperfusion, focusing on EAAC1.

scholarly journals Transcriptome Changes in Pseudomonas putida KT2440 during Medium-Chain-Length Polyhydroxyalkanoate Synthesis Induced by Nitrogen Limitation

2020 ◽  
Vol 22 (1) ◽  
pp. 152
Author(s):  
Dorota Dabrowska ◽  
Justyna Mozejko-Ciesielska ◽  
Tomasz Pokój ◽  
Slawomir Ciesielski
Keyword(s):  
Chain Length ◽  
Nitrogen Limitation ◽  
Stringent Response ◽  
Wild Type ◽  
Pseudomonas Putida Kt2440 ◽  
Medium Chain ◽  
Environmental Stimuli ◽  
Medium Chain Length ◽  
In The Wild

Pseudomonas putida’s versatility and metabolic flexibility make it an ideal biotechnological platform for producing valuable chemicals, such as medium-chain-length polyhydroxyalkanoates (mcl-PHAs), which are considered the next generation bioplastics. This bacterium responds to environmental stimuli by rearranging its metabolism to improve its fitness and increase its chances of survival in harsh environments. Mcl-PHAs play an important role in central metabolism, serving as a reservoir of carbon and energy. Due to the complexity of mcl-PHAs’ metabolism, the manner in which P. putida changes its transcriptome to favor mcl-PHA synthesis in response to environmental stimuli remains unclear. Therefore, our objective was to investigate how the P. putida KT2440 wild type and mutants adjust their transcriptomes to synthesize mcl-PHAs in response to nitrogen limitation when supplied with sodium gluconate as an external carbon source. We found that, under nitrogen limitation, mcl-PHA accumulation is significantly lower in the mutant deficient in the stringent response than in the wild type or the rpoN mutant. Transcriptome analysis revealed that, under N-limiting conditions, 24 genes were downregulated and 21 were upregulated that were common to all three strains. Additionally, potential regulators of these genes were identified: the global anaerobic regulator (Anr, consisting of FnrA, Fnrb, and FnrC), NorR, NasT, the sigma54-dependent transcriptional regulator, and the dual component NtrB/NtrC regulator all appear to play important roles in transcriptome rearrangement under N-limiting conditions. The role of these regulators in mcl-PHA synthesis is discussed.

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