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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 -
International Journal of Biological... Jun 2024Antarctic krill shell waste (AKSW), a byproduct of Antarctic krill processing, has substantial quantity but low utilization. Utilizing microbial-based cell factories,...
Antarctic krill shell waste (AKSW), a byproduct of Antarctic krill processing, has substantial quantity but low utilization. Utilizing microbial-based cell factories, with Pseudomonas putida as a promising candidate, offers an ecofriendly and sustainable approach to producing valuable bioproducts from renewable sources. However, the high fluoride content in AKSW impedes the cell growth of P. putida. This study aims to investigate the transcriptional response of P. putida to fluoride stress from AKSW and subsequently conduct genetic modification of the strain based on insights gained from transcriptomic analysis. Notably, the engineered strain KT exhibited a remarkable 33.7-fold increase in cell growth, capable of fermenting AKSW for medium-chain-length-polyhydroxyalkanoates (mcl-PHA) biosynthesis, achieving a 40.3-fold increase in mcl-PHA yield compared to the control strain. This research advances our understanding of how P. putida responds to fluoride stress from AKSW and provides engineered strains that serve as excellent platforms for producing mcl-PHA through AKSW.
PubMed: 38917919
DOI: 10.1016/j.ijbiomac.2024.133364 -
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 -
The Journal of the Association of... Apr 2024is a rare pathogen that primarily causes nosocomial infection. It is usually seen in immune dysfunction or immunocompromised patients and patients with invasive medical...
is a rare pathogen that primarily causes nosocomial infection. It is usually seen in immune dysfunction or immunocompromised patients and patients with invasive medical devices. Here, we present a rare case of bacteremia in a patient with cirrhosis of the liver.
Topics: Humans; Bacteremia; Pseudomonas putida; Liver Cirrhosis; Pseudomonas Infections; Male; Anti-Bacterial Agents; Middle Aged
PubMed: 38881090
DOI: 10.59556/japi.72.0416 -
ACS Synthetic Biology Jun 2024Transcription factor (TF)-based biosensors are useful synthetic biology tools for applications in a variety of areas of biotechnology. A major challenge of biosensor...
Transcription factor (TF)-based biosensors are useful synthetic biology tools for applications in a variety of areas of biotechnology. A major challenge of biosensor circuits is the limited repertoire of identified and well-characterized TFs for applications of interest, in addition to the challenge of optimizing selected biosensors. In this work, we implement the IclR family repressor TF TtgV from DOT-T1E as an indole-derivative biosensor in . We optimize the genetic circuit utilizing different components, providing insights into biosensor design and expanding on previous studies investigating this TF. We discover novel physiologically relevant ligands of TtgV, such as skatole. The broad specificity of TtgV makes it a useful target for directed evolution and protein engineering toward desired specificity. TtgV, as an indole-derivative biosensor, is a promising genetic component for the detection of compounds with biological activities relevant to health and the gut microbiome.
PubMed: 38875315
DOI: 10.1021/acssynbio.3c00736 -
Environmental Microbiology Jun 2024The environmental bacterium, Pseudomonas putida, possesses a broad spectrum of metabolic pathways. This makes it highly promising for use in biotechnological production...
The environmental bacterium, Pseudomonas putida, possesses a broad spectrum of metabolic pathways. This makes it highly promising for use in biotechnological production as a cell factory, as well as in bioremediation strategies to degrade various aromatic pollutants. For P. putida to flourish in its environment, it must withstand the continuous threats posed by bacteriophages. Interestingly, until now, only a handful of phages have been isolated for the commonly used laboratory strain, P. putida KT2440, and no phage defence mechanisms have been characterized. In this study, we present a new Collection of Environmental P. putida Phages from Estonia, or CEPEST. This collection comprises 67 double-stranded DNA phages, which belong to 22 phage species and 9 phage genera. Our findings reveal that most phages in the CEPEST collection are more infectious at lower temperatures, have a narrow host range, and require an intact lipopolysaccharide for P. putida infection. Furthermore, we show that cryptic prophages present in the P. putida chromosome provide strong protection against the infection of many phages. However, the chromosomal toxin-antitoxin systems do not play a role in the phage defence of P. putida. This research provides valuable insights into the interactions between P. putida and bacteriophages, which could have significant implications for biotechnological and environmental applications.
Topics: Pseudomonas putida; Host Specificity; Prophages; Pseudomonas Phages; Estonia; Bacteriophages
PubMed: 38863081
DOI: 10.1111/1462-2920.16671 -
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