scholarly journals A Pseudomonas plant pathogen uses distinct modes of stationary phase persistence to survive bacteriocin and streptomycin treatments

2021 ◽  
Author(s):  
Ravikumar R. Patel ◽  
Prem P. Kandel ◽  
Eboni Traverso ◽  
Kevin L. Hockett ◽  
Lindsay R. Triplett
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Host Plants ◽  
Recurrent Infection ◽  
Small Population ◽  
Antimicrobial Treatment ◽  
Redox Activity ◽  
Redox States ◽  
Redox Active ◽  
Biological Compounds

Abstract Antimicrobial treatment of bacteria often results in a small population of surviving tolerant cells, or persisters, that may contribute to recurrent infection. Antibiotic persisters are metabolically dormant, but the basis of persistence to membrane-disrupting biological compounds is less well-understood. We previously found that the model plant pathogen Pseudomonas syringae pv. phaseolicola 1448A (Pph) exhibits persistence to tailocin, a membrane-disrupting biocontrol compound with potential for sustainable disease control. Here we compared physiological traits associated with persistence to tailocin and to the antibiotic streptomycin, and established that both treatments leave similar frequencies of persisters. Microscopic profiling of treated populations revealed that while tailocin rapidly permeabilizes most cells, streptomycin treatment results in a heterogeneous population of redox and membrane permeability states. Sorting cells according to redox reporter intensity identified streptomycin persisters among the low-redox fraction, but tailocin persisters were only cultured from the fraction with intermediate redox activity. Cells from culturable fractions were able to infect host plants, while nonculturable redox-active cells were not. Tailocin and streptomycin were effective in eliminating all persisters when applied sequentially, in addition to eliminating cells in other viable states. This study identifies distinct redox states associated with antibiotic persistence, tailocin persistence, and virulence, and demonstrates that tailocin is highly effective in eliminating dormant cells.

scholarly journals Pseudomonas syringae pv. phaseolicola Uses Distinct Modes of Stationary-Phase Persistence To Survive Bacteriocin and Streptomycin Treatments

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Ravikumar R. Patel ◽  
Prem P. Kandel ◽  
Eboni Traverso ◽  
Kevin L. Hockett ◽  
Lindsay R. Triplett
Keyword(s):  
Pseudomonas Syringae ◽  
Metabolic Activity ◽  
Recurrent Infection ◽  
Small Population ◽  
Antimicrobial Treatment ◽  
Intact Cells ◽  
Content Type ◽  
Redox States ◽  
Metabolic States ◽  
Metabolic Signal

ABSTRACT Antimicrobial treatment of bacteria often results in a small population of surviving tolerant cells, or persisters, that may contribute to recurrent infection. Antibiotic persisters are metabolically dormant, but the basis of their persistence in the presence of membrane-disrupting biological compounds is less well understood. We previously found that the model plant pathogen Pseudomonas syringae pv. phaseolicola 1448A (Pph) exhibits persistence to tailocin, a membrane-disrupting biocontrol compound with potential for sustainable disease control. Here, we compared physiological traits associated with persistence to tailocin and to the antibiotic streptomycin and established that both treatments leave similar frequencies of persisters. Microscopic profiling of treated populations revealed that while tailocin rapidly permeabilizes most cells, streptomycin treatment results in a heterogeneous population in the redox and membrane permeability state. Intact cells were sorted into three fractions according to metabolic activity, as indicated by a redox-sensing reporter dye. Streptomycin persisters were cultured from the fraction associated with the lowest metabolic activity, but tailocin persisters were cultured from a fraction associated with an active metabolic signal. Cells from culturable fractions were able to infect host plants, while the nonculturable fractions were not. Tailocin and streptomycin were effective in eliminating all persisters when applied sequentially, in addition to eliminating cells in other viable states. This study identifies distinct metabolic states associated with antibiotic persistence, tailocin persistence, and loss of virulence and demonstrates that tailocin is highly effective in eliminating dormant cells. IMPORTANCE Populations of genetically identical bacteria encompass heterogeneous physiological states. The small fraction of bacteria that are dormant can help the population survive exposure to antibiotics and other stresses, potentially contributing to recurring infection cycles in animal or plant hosts. Membrane-disrupting biological control treatments are effective in killing dormant bacteria, but these treatments also leave persister-like survivors. The current work demonstrates that in Pph, persisters surviving treatment with membrane-disrupting tailocin proteins have an elevated redox state compared to that of dormant streptomycin persisters. Combination treatment was effective in killing both persister types. Culturable persisters corresponded closely with infectious cells in each treated population, whereas the high-redox and unculturable fractions were not infectious. In linking redox states to heterogeneous phenotypes of tailocin persistence, streptomycin persistence, and infection capability, this work will inform the search for mechanisms and markers for each phenotype.

scholarly journals High-resolution cryo-EM structure of photosystem II reveals damage from high-dose electron beams

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Koji Kato ◽  
Naoyuki Miyazaki ◽  
Tasuku Hamaguchi ◽  
Yoshiki Nakajima ◽  
Fusamichi Akita ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Physiological State ◽  
High Dose ◽  
Final State ◽  
X Ray ◽  
Redox States ◽  
X Ray Crystallography ◽  
Cryo Electron Microscopy ◽  
Redox Active ◽  
Beam Damage

AbstractPhotosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure and some intermediate structures. However, these structures are in the crystalline state and its final state structure has not been solved. Here we analyzed the structure of PSII in solution at 1.95 Å resolution by single-particle cryo-electron microscopy (cryo-EM). The structure obtained is similar to the crystal structure, but a PsbY subunit was visible in the cryo-EM structure, indicating that it represents its physiological state more closely. Electron beam damage was observed at a high-dose in the regions that were easily affected by redox states, and reducing the beam dosage by reducing frames from 50 to 2 yielded a similar resolution but reduced the damage remarkably. This study will serve as a good indicator for determining damage-free cryo-EM structures of not only PSII but also all biological samples, especially redox-active metalloproteins.

scholarly journals The type III effector repertoire of Pseudomonas syringae pv. syringae B728a and its role in survival and disease on host and non-host plants

2006 ◽  
Vol 62 (1) ◽  
pp. 26-44 ◽  
Author(s):  
Boris A. Vinatzer ◽  
Gail M. Teitzel ◽  
Min-Woo Lee ◽  
Joanna Jelenska ◽  
Sara Hotton ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Host Plants ◽  
Type Iii Effector ◽  
Type Iii

scholarly journals Exploring Coupled Redox and pH Processes with a Force Field-Based Approach: Applications to Five Different Systems

2020 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Gustavo Troiano Feliciano ◽  
Adrian Roitberg
Keyword(s):  
Force Field ◽  
Redox Potential ◽  
Desulfovibrio Vulgaris ◽  
Cytochrome C3 ◽  
Computational Tools ◽  
Redox States ◽  
Computational Performance ◽  
Redox Active ◽  
Constant Ph ◽  
Experimental Findings

Coupled redox and pH-driven processes are at the core of many important biological mechanisms. As the distribution of protonation and redox states in a system is associated with the pH and redox potential of the solution, having efficient computational tools that can simulate under these conditions become very important. Such tools have the potential to provide information that complement and drive experiments. In previous publications we have presented the implementation of the constant pH and redox potential molecular dynamics (C(pH,E)MD) method in AMBER and we have shown how multidimensional replica exchange can be used to significantly enhance the convergence efficiency of our simulations. In the current work, after an improvement in our C(pH,E)MD approach that allows a given residue to be simultaneously pH- and redox-active, we have employed our methodologies to study five different systems of interest in the literature. We present results for: capped tyrosine dipeptide, two maquette systems containing one pH- and redox-active tyrosine (α3Y and peptide A), and two proteins that contain multiple heme groups (diheme cytochrome c from Rhodobacter sphaeroides and Desulfovibrio vulgaris Hildenborough cytochrome c3). We show that our results can provide new insights into previous theoretical and experimental findings by using a fully force field-based and GPUaccelerated approach, which allows the simulations to be executed with high computational performance.

Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000

2021 ◽  
Author(s):  
Arnaud-Thierry Djami-Tchatchou ◽  
Zipeng Alex Li ◽  
Paul Stodghill ◽  
Melanie J. Filiatrault ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Stress Response ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Type Iii Secretion ◽  
Plant Hormone ◽  
Indole 3 Acetic Acid ◽  
Exogenous Iaa

The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 ( Pto DC3000). To learn more about the impact of IAA on regulation of Pto DC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta . Collectively the data indicate that IAA modulates many aspects of Pto DC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain Pto DC000 and one of its hosts, Arabidopsis thaliana . However, the mechanisms by which IAA impacts the biology of Pto DC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in Pto DC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.

scholarly journals Redox-Active Monolayers Self-Assembled on Gold Electrodes—Effect of Their Structures on Electrochemical Parameters and DNA Sensing Ability

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 607 ◽  
Author(s):  
Kamila Malecka ◽  
Shalini Menon ◽  
Gopal Palla ◽  
Krishnapillai Girish Kumar ◽  
Mathias Daniels ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Transition Metal ◽  
Redox Activity ◽  
Gold Electrodes ◽  
Complex Structures ◽  
Transfer Coefficients ◽  
Sensing Properties ◽  
Redox Active ◽  
Electrochemical Parameters ◽  
Self Assembled

The background: The monolayers self-assembled on the gold electrode incorporated transition metal complexes can act both as receptor (“host” molecules) immobilization sites, as well as transducer for interface recognitions of “guest” molecules present in the aqueous solutions. Their electrochemical parameters influencing the sensing properties strongly depend on the transition metal complex structures. The objectives: The electrochemical characterization of the symmetric terpyridine–M2+–terpyridine and asymmetric dipyrromethene–M2+–terpyridine complexes modified with ssDNA probe covalently attached to the gold electrodes and exploring their ssDNA sensing ability were the main aims of the research presented. The methods: Two transition metal cations have been selected: Cu2+ and Co2+ for creation of redox-active monolayers. The electron transfer coefficients indicating the reversibility and electron transfer rate constant measuring kinetic of redox reactions have been determined for all SAMs studied using: Cyclic Voltammetry, Osteryoung Square-Wave Voltammetry, and Differential Pulse Voltammetry. All redox-active platforms have been applied for immobilization of ssDNA probe. Next, their sensing properties towards complementary DNA target have been explored electrochemically. The results: All SAMs studied were stable displaying quasi-reversible redox activity. The linear relationships between cathodic and anodic current vs. san rate were obtained for both symmetric and asymmetric SAMs incorporating Co2+ and Cu2+, indicating that oxidized and reduced redox sites are adsorbed on the electrode surface. The ssDNA sensing ability were observed in the fM concentration range. The low responses towards non-complementary ssDNA sequences provided evidences for sensors good selectivity. The conclusions: All redox-active SAMs modified with a ssDNA probe were suitable for sensing of ssDNA target, with very good sensitivity in fM range and very good selectivity. The detection limits obtained for SAMs incorporating Cu2+, both symmetric and asymmetric, were better in comparison to SAMs incorporating Co2+. Thus, selection of the right transition metal cation has stronger influence on ssDNA sensing ability, than complex structures.

scholarly journals Selenium Anticancer Properties and Impact on Cellular Redox Status

Antioxidants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 80 ◽  
Author(s):  
Lolita Kuršvietienė ◽  
Aušra Mongirdienė ◽  
Jurga Bernatonienė ◽  
Jurgita Šulinskienė ◽  
Inga Stanevičienė
Keyword(s):  
Anticancer Activity ◽  
Antioxidant Activities ◽  
Chemotherapeutic Agents ◽  
Redox Activity ◽  
Biological Functions ◽  
Cellular Redox ◽  
Selenium Compounds ◽  
Anticancer Properties ◽  
Redox Active ◽  
The Impact

(1) Background: In this review, we provide information published in recent years on the chemical forms, main biological functions and especially on antioxidant and prooxidant activities of selenium. The main focus is put on the impact of selenoproteins on maintaining cellular redox balance and anticancerogenic function. Moreover, we summarize data on chemotherapeutic application of redox active selenium compounds. (2) Methods: In the first section, main aspects of metabolism and redox activity of selenium compounds is reviewed. The second outlines multiple biological functions, asserted when selenium is incorporated into the structure of selenoproteins. The final section focuses on anticancer activity of selenium and chemotherapeutic application of redox active selenium compounds as well. (3) Results: optimal dietary level of selenium ensures its proper antioxidant and anticancer activity. We pay special attention to antioxidant activities of selenium compounds, especially selenoproteins, and their importance in antioxidant defence. It is worth noting, that data on selenium anticancer properties is still contraversive. Moreover, selenium compounds as chemotherapeutic agents usually are used at supranutritional doses. (4) Conclusions: Selenium play a vital role for many organism systems due to its incorporation into selenoproteins structure. Selenium possesses antioxidant activity at optimal doses, while at supranutritional doses, it displays prooxidant activity. Redox active selenium compounds can be used for cancer treatment; recently special attention is put to selenium containing nanoparticles.

scholarly journals Genome Sequence of Pantoea ananatis LMG20103, the Causative Agent of Eucalyptus Blight and Dieback

2010 ◽  
Vol 192 (11) ◽  
pp. 2936-2937 ◽  
Author(s):  
Pieter De Maayer ◽  
Wai Yin Chan ◽  
Stephanus N. Venter ◽  
Ian K. Toth ◽  
Paul R. J. Birch ◽  
...  
Keyword(s):  
South Africa ◽  
Genome Sequence ◽  
Causative Agent ◽  
Plant Pathogen ◽  
Human Disease ◽  
Host Plants ◽  
Pantoea Ananatis ◽  
Gram Negative

ABSTRACT Pantoea ananatis is a Gram-negative plant pathogen that causes disease on a broad range of host plants, including pineapple, maize, rice, onion, melons, and Eucalyptus, and has been implicated in several cases of human disease. Here, we report the genome sequence of P. ananatis LMG20103 isolated from diseased Eucalyptus in South Africa.

scholarly journals Stepwise synthesis of a Ru4Cd4 coordination cage using inert and labile subcomponents: introduction of redox activity at specific sites

2014 ◽  
Vol 50 (48) ◽  
pp. 6330-6332 ◽  
Author(s):  
Alexander J. Metherell ◽  
Michael D. Ward
Keyword(s):  
Binding Sites ◽  
Redox Activity ◽  
Stepwise Synthesis ◽  
Redox Active

Combination of four [RuL3]2+ units, each with three pendant binding sites, and four Cd2+ ions affords the redox-active, heteronuclear, cubic cage [Ru4Cd4L12]16+.

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