-
Life (Basel, Switzerland) Jun 2024"Lauren N [...].
"Lauren N [...].
PubMed: 38929766
DOI: 10.3390/life14060767 -
Biology Jun 2024KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt...
KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt tolerance of KT2440 has hindered its application. In this study, the strain KT2440 was tested to tolerate a maximum of 4% / NaCl cultured with minimal salts medium. Transcriptomic data in a high-salinity environment showed significant expression changes in genes in membrane components, redox processes, chemotaxis, and cellular catabolic processes. -encoding betaine-aldehyde dehydrogenase was identified from the transcriptome data to overexpress and enhance growth profile of the strain KT2440 in minimal salts medium containing 4% / NaCl. Meanwhile, screening for exogenous salt-tolerant genes revealed that the Na/H antiporter from significantly increased the growth of the strain KT2440 in 4% / NaCl. Then, co-expression of and (KT2440-) increased the maximum salt tolerance of strain KT2440 to 5% / NaCl. Further addition of betaine and proline improved the salt tolerance of the engineered strain to 6% / NaCl. Finally, the engineered strain KT2440- was able to degrade 56.70% of benzoic acid and 95.64% of protocatechuic acid in minimal salt medium containing 4% / NaCl in 48 h, while no biodegradation was observed in the normal strain KT2440 in the same conditions. However, the strain KT2440- failed to degrade catechol in minimal salt medium containing 3% / NaCl. This study illustrated the improvement in the salt tolerance performance of KT2440 and the feasibility of engineered strain KT2440 as a potential salt-tolerant bioremediation platform.
PubMed: 38927284
DOI: 10.3390/biology13060404 -
Biology May 2024Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is...
Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is essential for virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and virulence were barely pursued. In this study, we hypothesized that deficiency affected 7-hydroxytropolone (7-HT) biosynthesis and redox levels, thereby reducing bacterial virulence. There are four genes in HYS, and we reported for the first time that deletion of significantly reduced the virulence of HYS towards , whereas the reduction in virulence by the other three genes was not significant. Interestingly, deletion significantly reduced colonization of HYS in the gut of . Further studies showed that HemN2 was regulated by GacS and participated in the virulence of HYS towards by mediating the synthesis of the virulence factor 7-HT. In addition, HemN2 and GacS regulated the virulence of HYS by affecting antioxidant capacity and nitrative stress. In short, the findings that HemN2 was regulated by the Gac system and that it was involved in bacterial virulence via regulating 7-HT synthesis and redox levels were reported for the first time. These insights may enlighten further understanding of HemN-based virulence in the genus .
PubMed: 38927253
DOI: 10.3390/biology13060373 -
Microbial Biotechnology Jun 2024Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acid cycle. We investigated how the loss...
Inactivation of Pseudomonas putida KT2440 pyruvate dehydrogenase relieves catabolite repression and improves the usefulness of this strain for degrading aromatic compounds.
Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acid cycle. We investigated how the loss of PDH affects metabolism in Pseudomonas putida. PDH inactivation resulted in a strain unable to utilize compounds whose assimilation converges at pyruvate, including sugars and several amino acids, whereas compounds that generate acetyl-CoA supported growth. PDH inactivation also resulted in the loss of carbon catabolite repression (CCR), which inhibits the assimilation of non-preferred compounds in the presence of other preferred compounds. Pseudomonas putida can degrade many aromatic compounds, most of which produce acetyl-CoA, making it useful for biotransformation and bioremediation. However, the genes involved in these metabolic pathways are often inhibited by CCR when glucose or amino acids are also present. Our results demonstrate that the PDH-null strain can efficiently degrade aromatic compounds even in the presence of other preferred substrates, which the wild-type strain does inefficiently, or not at all. As the loss of PDH limits the assimilation of many sugars and amino acids and relieves the CCR, the PDH-null strain could be useful in biotransformation or bioremediation processes that require growth with mixtures of preferred substrates and aromatic compounds.
Topics: Pseudomonas putida; Catabolite Repression; Pyruvate Dehydrogenase Complex; Hydrocarbons, Aromatic; Biodegradation, Environmental; Acetyl Coenzyme A; Pyruvic Acid; Gene Deletion; Metabolic Networks and Pathways
PubMed: 38923400
DOI: 10.1111/1751-7915.14514 -
Scientific Reports Jun 2024Aloe barbadensis is a drought-tolerant perennial medicinal plant with both nutritional and cosmetic uses. Drought is one of the main abiotic stresses limiting plant...
Evaluation of the benefits of plant growth-promoting rhizobacteria and mycorrhizal fungi on biochemical and morphophysiological traits of Aloe barbadensis Mill under water deficit stress.
Aloe barbadensis is a drought-tolerant perennial medicinal plant with both nutritional and cosmetic uses. Drought is one of the main abiotic stresses limiting plant growth and development. However, the use of drought-resistant plants combined with beneficial soil micro-organisms could improve the effectiveness of biological methods to mitigate drought damage. This research aims to evaluate the effects of Funneliformis mosseae (MF), plant growth-promoting rhizobacteria (PGPR) (including Pseudomonas putida and Pantoea agglomerans), and their co-inoculation on the macronutrient status, antioxidant enzyme activities, and other morphophysiological traits of A. barbadensis under four irrigation regimes [25%, 50%, 75% and 100% of water requirement (WR)]. Three harvests were conducted, revealing that inoculation enhanced the survival rate and shoot fresh weight (SFW) compared to the control plants. However, at 25% WR, the SFW was reduced by 43% more than the control. across all harvests, while the PGPR + MF treatment showed increases of more than 19%, 11%, and 17% compared to the control, MF, and PGPR treatments, respectively. The results also showed that A. barbadensis exhibited innate drought tolerance up to a 50% WR level by enhancing physiological defenses, such as antioxidant enzyme activity. Inoculation increased the macronutrient status of the plant at all levels of irrigation regimes especially under severe drought conditions. The highest levels of nitrogen (N) (16.24 mg g DW) and phosphorus (P) (11.29 mg g DW) were observed in the PGPR + MF treatment at 100% WR. The maximum relative water content under MF inoculation and 75% WR (98.24%) (98.24%) was reached. PGPR + MF treatment alleviated drought-induced osmotic stress, as indicated by reduced antioxidant enzyme activities and electrolyte leakage. However, P. putida and P. agglomerans strains alone or in combination with F. mosseae increased plant yield, macronutrient uptake and antioxidant enzyme activity. This study underscores the potential of these PGPR and MF strains as invaluable biological tools for the cultivation of A. barbadensis in regions with severe drought stress.
Topics: Aloe; Mycorrhizae; Droughts; Pseudomonas putida; Antioxidants; Plant Roots; Water; Stress, Physiological; Soil Microbiology; Pantoea; Dehydration; Fungi
PubMed: 38914637
DOI: 10.1038/s41598-024-64878-9 -
Nature Communications Jun 2024Adenosine-5'-triphosphate (ATP), the primary energy currency in cellular processes, drives metabolic activities and biosynthesis. Despite its importance, understanding...
Adenosine-5'-triphosphate (ATP), the primary energy currency in cellular processes, drives metabolic activities and biosynthesis. Despite its importance, understanding intracellular ATP dynamics' impact on bioproduction and exploiting it for enhanced bioproduction remains largely unexplored. Here, we harness an ATP biosensor to dissect ATP dynamics across different growth phases and carbon sources in multiple microbial strains. We find transient ATP accumulations during the transition from exponential to stationary growth phases in various conditions, coinciding with fatty acid (FA) and polyhydroxyalkanoate (PHA) production in Escherichia coli and Pseudomonas putida, respectively. We identify carbon sources (acetate for E. coli, oleate for P. putida) that elevate steady-state ATP levels and boost FA and PHA production. Moreover, we employ ATP dynamics as a diagnostic tool to assess metabolic burden, revealing bottlenecks that limit limonene bioproduction. Our results not only elucidate the relationship between ATP dynamics and bioproduction but also showcase its value in enhancing bioproduction in various microbial species.
Topics: Adenosine Triphosphate; Biosensing Techniques; Escherichia coli; Pseudomonas putida; Fatty Acids; Polyhydroxyalkanoates; Energy Metabolism; Carbon; Oleic Acid
PubMed: 38906854
DOI: 10.1038/s41467-024-49579-1 -
Applied Microbiology and Biotechnology Jun 2024Ethylene glycol (EG) is an industrially important two-carbon diol used as a solvent, antifreeze agent, and building block of polymers such as poly(ethylene... (Review)
Review
Ethylene glycol (EG) is an industrially important two-carbon diol used as a solvent, antifreeze agent, and building block of polymers such as poly(ethylene terephthalate) (PET). Recently, the use of EG as a starting material for the production of bio-fuels or bio-chemicals is gaining attention as a sustainable process since EG can be derived from materials not competing with human food stocks including CO, syngas, lignocellulolytic biomass, and PET waste. In order to design and construct microbial process for the conversion of EG to value-added chemicals, microbes capable of catabolizing EG such as Escherichia coli, Pseudomonas putida, Rhodococcus jostii, Ideonella sakaiensis, Paracoccus denitrificans, and Acetobacterium woodii are candidates of chassis for the construction of synthetic pathways. In this mini-review, we describe EG catabolic pathways and catabolic enzymes in these microbes, and further review recent advances in microbial conversion of EG to value-added chemicals by means of metabolic engineering. KEY POINTS: • Ethylene glycol is a potential next-generation feedstock for sustainable industry. • Microbial conversion of ethylene glycol to value-added chemicals is gaining attention. • Ethylene glycol-utilizing microbes are useful as chassis for synthetic pathways.
Topics: Ethylene Glycol; Metabolic Engineering; Metabolic Networks and Pathways; Bacteria; Pseudomonas putida; Biofuels; Escherichia coli
PubMed: 38861200
DOI: 10.1007/s00253-024-13179-2 -
Microbiology Resource Announcements Jun 2024We report the complete genome of strain WBB028, which exhibits broad-spectrum antifungal activity. This strain was isolated from leaf litter collected at Walker Branch...
We report the complete genome of strain WBB028, which exhibits broad-spectrum antifungal activity. This strain was isolated from leaf litter collected at Walker Branch Watershed located on the Oak Ridge Reservation in eastern Tennessee (35.9614 N 84.2864 W). The genome is 6.3 Mbp with a 62.5% GC content.
PubMed: 38860815
DOI: 10.1128/mra.00234-24 -
Genome Biology and Evolution Jun 2024Many nonsporulating bacterial species survive prolonged resource exhaustion, by entering a state termed long-term stationary phase. Here, we performed long-term...
Many nonsporulating bacterial species survive prolonged resource exhaustion, by entering a state termed long-term stationary phase. Here, we performed long-term stationary phase evolutionary experiments on the bacterium Pseudomonas putida, followed by whole-genome sequencing of evolved clones. We show that P. putida is able to persist and adapt genetically under long-term stationary phase. We observed an accumulation of mutations within the evolving P. putida populations. Within each population, independently evolving lineages are established early on and persist throughout the 4-month-long experiment. Mutations accumulate in a highly convergent manner, with similar loci being mutated across independently evolving populations. Across populations, mutators emerge, that due to mutations within mismatch repair genes developed a much higher rate of mutation than other clones with which they coexisted within their respective populations. While these general dynamics of the adaptive process are quite similar to those we previously observed in the model bacterium Escherichia coli, the specific loci that are involved in adaptation only partially overlap between P. putida and E. coli.
Topics: Pseudomonas putida; Adaptation, Physiological; Mutation; Genome, Bacterial; Evolution, Molecular
PubMed: 38849986
DOI: 10.1093/gbe/evae117 -
PloS One 2024Cellular metabolic activity can be detected by tetrazolium-based colorimetric assays, which rely on dehydrogenase enzymes from living cells to reduce tetrazolium...
Cellular metabolic activity can be detected by tetrazolium-based colorimetric assays, which rely on dehydrogenase enzymes from living cells to reduce tetrazolium compounds into colored formazan products. Although these methods have been used in different fields of microbiology, their application to the detection of bacteria with plastic-degrading activity has not been well documented. Here, we report a microplate-adapted method for the detection of bacteria metabolically active on the commercial polyester polyurethane (PU) Impranil®DLN using the tetrazolium salt 2,3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT). Bacterial cells that are active on PU reduce XTT to a water-soluble orange dye, which can be quantitatively measured using a microplate reader. We used the Pseudomonas putida KT2440 strain as a study model. Its metabolic activity on Impranil detected by our novel method was further verified by Fourier-transform infrared spectroscopy (FTIR) analyses. Measurements of the absorbance of reduced XTT at 470 nm in microplate wells were not affected by the colloidal properties of Impranil or cell density. In summary, we provide here an easy and high-throughput method for screening bacteria active on PU that can be adapted to other plastic substrates.
Topics: Polyurethanes; Pseudomonas putida; Tetrazolium Salts; Spectroscopy, Fourier Transform Infrared; Water; Colorimetry
PubMed: 38843174
DOI: 10.1371/journal.pone.0303210