Influence of flagellin polymorphisms, gene regulation, and responsive memory on the motility of Xanthomonas species that cause bacterial spot disease of solanaceous plants

Increasingly, new evidence has demonstrated variability in the epitope regions of bacterial flagellin, including in regions harboring the microbe-associated molecular patterns flg22 and flgII-28 that are recognized by the pattern recognition receptors FLS2 and FLS3, respectively. Additionally, since bacterial motility is known to contribute to pathogen virulence and chemotaxis, reductions in or loss of motility can significantly reduce bacterial fitness. In this study, we determined that variations in flg22 and flgII-28 epitopes allow some, but not all, Xanthomonas species to evade both FLS2-and FLS3-mediated oxidative burst responses. We observed variation in the motility for many isolates, irrespective of their flagellin sequence. Instead, we determined that past growth conditions may have a significant impact on the motility status of isolates, as we could minimize this variability by inducing motility using chemoattractant assays. Additionally, motility could be significantly suppressed under nutrient-limited conditions, and bacteria could “remember” its prior motility status after storage at ultra-cold temperatures. Finally, we observed larger bacterial populations of strains with flagellin variants predicted not to be recognized by either FLS2 or FLS3, suggesting that these bacteria can evade flagellin recognition in tomato plants. While some flagellin variants may impart altered motility and differential recognition by the host immune system, external growth parameters and gene expression regulation appear to have more significant impacts on the motility phenotypes for these Xanthomonas species.

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Fitness Trade-Offs Resulting from Bacteriophage Resistance Potentiate Synergistic Antibacterial Strategies

Infection and Immunity ◽

10.1128/iai.00926-19 ◽

2020 ◽

Vol 88 (7) ◽

Cited By ~ 4

Author(s):

Mihnea R. Mangalea ◽

Breck A. Duerkop

Keyword(s):

Bacterial Pathogens ◽

Resistant Bacteria ◽

Phage Resistance ◽

Host Immune System ◽

Bacterial Populations ◽

New Therapeutic Approaches ◽

Trade Offs ◽

System Pressure ◽

Life Threatening ◽

Bacterial Fitness

ABSTRACT Bacteria that cause life-threatening infections in humans are becoming increasingly difficult to treat. In some instances, this is due to intrinsic and acquired antibiotic resistance, indicating that new therapeutic approaches are needed to combat bacterial pathogens. There is renewed interest in utilizing viruses of bacteria known as bacteriophages (phages) as potential antibacterial therapeutics. However, critics suggest that similar to antibiotics, the development of phage-resistant bacteria will halt clinical phage therapy. Although the emergence of phage-resistant bacteria is likely inevitable, there is a growing body of literature showing that phage selective pressure promotes mutations in bacteria that allow them to subvert phage infection, but with a cost to their fitness. Such fitness trade-offs include reduced virulence, resensitization to antibiotics, and colonization defects. Resistance to phage nucleic acid entry, primarily via cell surface modifications, compromises bacterial fitness during antibiotic and host immune system pressure. In this minireview, we explore the mechanisms behind phage resistance in bacterial pathogens and the physiological consequences of acquiring phage resistance phenotypes. With this knowledge, it may be possible to use phages to alter bacterial populations, making them more tractable to current therapeutic strategies.

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Xanthones Production in Gentiana dinarica Beck Hairy Root Cultures Grown in Simple Bioreactors

Plants ◽

10.3390/plants10081610 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1610

Author(s):

Branka Vinterhalter ◽

Nevena Banjac ◽

Dragan Vinterhalter ◽

Dijana Krstić-Milošević

Keyword(s):

Hairy Root ◽

Large Scale ◽

Bubble Column ◽

Growth Parameters ◽

Growth Index ◽

Dry Weight ◽

Growth Conditions ◽

Good Growth ◽

Gentiana Dinarica ◽

Hairy Root Clones

The hairy root clones of Gentiana dinarica cl-B, cl-D, cl-3, and cl-14 were cultivated in parallel in diverse simple bioreactors, including temporary immersion systems RITA® (TIS RITA®), bubble column bioreactors (BCB), and Erlenmeyer flasks (EF), and evaluated for biomass production and xanthone content. The obtained results showed that TIS RITA® and BCB containing ½ MS medium with 4% sucrose provided equally good growth conditions in which the majority of the clones displayed the higher percentage of dry matter (DM%), and xanthones norswertianin-1-O-primeveroside (nor-1-O-prim) and norswertianin production than those cultivated in EF. Thin and well branched hairy root clone cl-B grown in BCB for 7 weeks was superior regarding all growth parameters tested, including growth index (19.97), dry weight (2.88 g), and DM% (25.70%) compared to all other clones. Cl-B cultured in TIS RITA® contained the highest amount of nor-1-O-prim (56.82 mg per vessel). In BCB with constant aeration, cl-B accumulated the highest norswertianin content reaching 18.08 mg/vessel. The optimized conditions for cultivation of selected G. dinarica hairy root clones in highly aerated TIS RITA® and BCB systems contribute to the development of bioreactor technology designed for the large scale commercial production of xanthones nor-1-O-prim and norswertianin.

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Temperature Sensitivity and Composition of Nitrate-Reducing Microbiomes from a Full-Scale Woodchip Bioreactor Treating Agricultural Drainage Water

Microorganisms ◽

10.3390/microorganisms9061331 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1331

Author(s):

Arnaud Jéglot ◽

Sebastian Reinhold Sørensen ◽

Kirk M. Schnorr ◽

Finn Plauborg ◽

Lars Elsgaard

Keyword(s):

Temperature Response ◽

Microbial Transformation ◽

Drainage Water ◽

Microbial Populations ◽

Agricultural Drainage ◽

Bacterial Populations ◽

Cold Temperatures ◽

Cold Adapted ◽

Agricultural Drainage Water ◽

Temperature Responses

Denitrifying woodchip bioreactors (WBR), which aim to reduce nitrate (NO3−) pollution from agricultural drainage water, are less efficient when cold temperatures slow down the microbial transformation processes. Conducting bioaugmentation could potentially increase the NO3− removal efficiency during these specific periods. First, it is necessary to investigate denitrifying microbial populations in these facilities and understand their temperature responses. We hypothesized that seasonal changes and subsequent adaptations of microbial populations would allow for enrichment of cold-adapted denitrifying bacterial populations with potential use for bioaugmentation. Woodchip material was sampled from an operating WBR during spring, fall, and winter and used for enrichments of denitrifiers that were characterized by studies of metagenomics and temperature dependence of NO3− depletion. The successful enrichment of psychrotolerant denitrifiers was supported by the differences in temperature response, with the apparent domination of the phylum Proteobacteria and the genus Pseudomonas. The enrichments were found to have different microbiomes’ composition and they mainly differed with native woodchip microbiomes by a lower abundance of the genus Flavobacterium. Overall, the performance and composition of the enriched denitrifying population from the WBR microbiome indicated a potential for efficient NO3− removal at cold temperatures that could be stimulated by the addition of selected cold-adapted denitrifying bacteria.

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An efficient and accurate method for obtaining regional scale rice growth conditions based on WOFOST model and satellite images

10.5194/egusphere-egu21-10688 ◽

2021 ◽

Author(s):

Bingyu Zhao ◽

Meiling Liu ◽

Jiianjun Wu ◽

Xiangnan Liu ◽

Mengxue Liu ◽

...

Keyword(s):

Remote Sensing ◽

Data Assimilation ◽

Growth Model ◽

Growth Parameters ◽

Remote Sensing Data ◽

Growth Conditions ◽

Crop Growth ◽

Crop Growth Model ◽

Parallel Method ◽

Rice Growth

<p>It is very important to obtain regional crop growth conditions efficiently and accurately in the agricultural field. The data assimilation between crop growth model and remote sensing data is a widely used method for obtaining vegetation growth information. This study aims to present a parallel method based on graphic processing unit (GPU) to improve the efficiency of the assimilation between RS data and crop growth model to estimate rice growth parameters. Remote sensing data, Landsat and HJ-1 images were collected and the World Food Studies (WOFOST) crop growth model which has a strong flexibility was employed. To acquire continuous regional crop parameters in temporal-spatial scale, particle swarm optimization (PSO) data assimilation method was used to combine remote sensing images and WOFOST and this process is accompanied by a parallel method based on the Compute Unified Device Architecture (CUDA) platform of NVIDIA GPU. With these methods, we obtained daily rice growth parameters of Zhuzhou City, Hunan, China and compared the efficiency and precision of parallel method and non-parallel method. Results showed that the parallel program has a remarkable speedup (reaching 240 times) compared with the non-parallel program with a similar accuracy. This study indicated that the parallel implementation based on GPU was successful in improving the efficiency of the assimilation between RS data and the WOFOST model and was conducive to obtaining regional crop growth conditions efficiently and accurately.</p>

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Characterisation of III?V Multilayers Grown by Low-pressure Metal Organic Vapour-phase Epitaxy

Australian Journal of Physics ◽

10.1071/ph930435 ◽

1993 ◽

Vol 46 (3) ◽

pp. 435

Author(s):

C Jagadish ◽

A Clark ◽

G Li ◽

CA Larson ◽

N Hauser ◽

...

Keyword(s):

Gallium Arsenide ◽

Growth Temperature ◽

Deep Level ◽

Growth Parameters ◽

Low Pressure ◽

Vapour Phase ◽

Growth Conditions ◽

Vapour Phase Epitaxy ◽

Metal Organic ◽

Organic Vapour

Undoped and doped layers of gallium arsenide and aluminium gallium arsenide have been grown on gallium arsenide by low-pressure metal organic vapour-phase epitaxy (MOVPE). Delta doping and growth on silicon substrates have also been attempted. Of particular interest in the present study has been the influence of growth parameters, such as growth temperature, group III mole fraction and dopant flow, on the electrical and physical properties of gallium arsenide layers. An increase in growth temperature leads to increased doping efficiency in the case of silicon, whereas the opposite is true in the case of zinc. Deep level transient spectroscopy (DTLS) studies on undoped GaAs layers showed two levels, the expected EL2 level and a carbon-related level. The determination of optimum growth conditions has allowed good quality GaAs and AlGaAs epitaxial layers to be produced for a range of applications.`

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Staphylococcal ClpXP protease targets the cellular antioxidant system to eliminate fitness-compromised cells in stationary phase

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2109671118 ◽

2021 ◽

Vol 118 (47) ◽

pp. e2109671118

Author(s):

Abdulelah A. Alqarzaee ◽

Sujata S. Chaudhari ◽

Mohammad Mazharul Islam ◽

Vikas Kumar ◽

Matthew C. Zimmerman ◽

...

Keyword(s):

Cell Death ◽

Stationary Phase ◽

Growth Conditions ◽

Significant Loss ◽

Protein Damage ◽

Bacterial Populations ◽

Competitive Fitness ◽

Functional Conservation ◽

Domains Of Life ◽

Expression And Activity

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure. Here, we demonstrate that staphylococci that enter stationary phase following growth in media supplemented with excess glucose, undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the acetate generated as a byproduct of glucose metabolism induces cytoplasmic acidification and extensive protein damage in nondividing cells. Although cell death ensues, it does not occur as a passive consequence of protein damage. Instead, we demonstrate that the expression and activity of the ClpXP protease is induced, resulting in the degeneration of cellular antioxidant capacity and, ultimately, cell death. Under these conditions, inactivation of either clpX or clpP resulted in the extended survival of unfit cells in stationary phase, but at the cost of maintaining population fitness. Finally, we show that cell death from antibiotics that interfere with bacterial protein synthesis can also be partly ascribed to the corresponding increase in clpP expression and activity. The functional conservation of ClpP in eukaryotes and bacteria suggests that ClpP-dependent cell death and fitness maintenance may be a widespread phenomenon in these domains of life.

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Effect of salicylic acid on pre-transplant acclimatization of native tomato populations

Horticultura Brasileira ◽

10.1590/s0102-053620180409 ◽

2018 ◽

Vol 36 (4) ◽

pp. 480-485

Author(s):

Wilberth A Poot-Poot ◽

Rafael Delgado-Martínez ◽

Sergio Castro-Nava ◽

Ma Teresa Segura-Martínez ◽

Alejandro Carreón-Pérez ◽

...

Keyword(s):

Salicylic Acid ◽

Growth And Development ◽

Growth Parameters ◽

Field Capacity ◽

Dry Weight ◽

Growth Conditions ◽

Peat Moss ◽

Hypocotyl Length ◽

Cell Processes ◽

Recorded Data

ABSTRACT The aim of this study was to evaluate the effect of salicylic acid (SA) application on pre-transplant acclimatization of native populations of tomato. SA is a growth regulator that modifies plant growth and development by inducing changes in cell processes, physiology and morphology. Five populations of native tomato were sown in polystyrene trays. Peat moss was used as substrate and plants were maintained at field capacity continuously. After emergence, seedlings were applied during three weeks with different concentration of SA (0.0, 0.01, 0.1, 0.5 and 1.0 μM). A completely random experimental design was used with five replications per treatment. The growth parameters evaluated were height, stem diameter, number of leaves, hypocotyl length, shoot fresh and dry weight (leaves and stem), and root length and fresh and dry weight. An analysis of variance was carried out, and means were compared with the Tukey test (5%) using SAS statistical software. The recorded data show that pre-transplant seedlings of each of the evaluated populations responded significantly (P=0.01) to the SA treatments. Also, the comparison of means of each of the factors under study showed positive changes. With the concentrations of 0.5 and 0.1 μM SA, higher values of the studied variables were obtained than with the concentrations 0.01 and 1.0 μM SA. The native tomato populations sprayed with SA at concentrations of 0.5 and 0.1 μM responded positively in terms of seedling growth and development. Based on these findings, SA treatments can help acclimatize and present better growth conditions to the seedlings before being transplanted.

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SlyA and HilD Counteract H-NS-Mediated Repression on the ssrAB Virulence Operon of Salmonella enterica Serovar Typhimurium and Thus Promote Its Activation by OmpR

Journal of Bacteriology ◽

10.1128/jb.00530-18 ◽

2019 ◽

Vol 201 (8) ◽

Cited By ~ 3

Author(s):

María M. Banda ◽

Crispín Zavala-Alvarado ◽

Deyanira Pérez-Morales ◽

Víctor H. Bustamante

Keyword(s):

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Growth Conditions ◽

The Other ◽

Regulatory Mechanisms ◽

Two Component System ◽

Content Type ◽

Additive Action ◽

Serovar Typhimurium ◽

Bacterial Fitness

ABSTRACT H-NS-mediated repression of acquired genes and the subsequent adaptation of regulatory mechanisms that counteract this repression have played a central role in the Salmonella pathogenicity evolution. The Salmonella pathogenicity island 2 (SPI-2) is an acquired chromosomal region containing genes necessary for Salmonella enterica to colonize and replicate in different niches of hosts. The ssrAB operon, located in SPI-2, encodes the two-component system SsrA-SsrB, which positively controls the expression of the SPI-2 genes but also other many genes located outside SPI-2. Several regulators have been involved in the expression of ssrAB, such as the ancestral regulators SlyA and OmpR, and the acquired regulator HilD. In this study, we show how SlyA, HilD, and OmpR coordinate to induce the expression of ssrAB under different growth conditions. We found that when Salmonella enterica serovar Typhimurium is grown in nutrient-rich lysogeny broth (LB), SlyA and HilD additively counteract H-NS-mediated repression on ssrAB, whereas in N-minimal medium (N-MM), SlyA antagonizes H-NS-mediated repression on ssrAB independently of HilD. Interestingly, our results indicate that OmpR is required for the expression of ssrAB independently of the growth conditions, even in the absence of repression by H-NS. Therefore, our data support two mechanisms adapted for the expression of ssrAB under different growth conditions. One involves the additive action of SlyA and HilD, whereas the other involves SlyA, but not HilD, to counteract H-NS-mediated repression on ssrAB, thus favoring in both cases the activation of ssrAB by OmpR. IMPORTANCE The global regulator H-NS represses the expression of acquired genes and thus avoids possible detrimental effects on bacterial fitness. Regulatory mechanisms are adapted to induce expression of the acquired genes in particular niches to obtain a benefit from the information encoded in the foreign DNA, as for pathogenesis. Here, we show two mechanisms that were integrated for the expression of virulence genes in Salmonella Typhimurium. One involves the additive action of the regulators SlyA and HilD, whereas the other involves SlyA, but not HilD, to counteract H-NS-mediated repression on the ssrAB operon, thus favoring its activation by the OmpR regulator. To our knowledge, this is the first report involving the coordinated action of two regulators to counteract H-NS-mediated repression.

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Biohardening of Arabidopsis thaliana Seeds and Seedlings with Fraser Photinia Associated Bacterium (PGB_invit) in In vitro Conditions

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha47311488 ◽

2019 ◽

Vol 47 (3) ◽

pp. 954-961

Author(s):

Maria BATOOL ◽

Özlem AKKAYA ◽

Mine GÜL ŞEKER ◽

Yelda ÖZDEN ÇİFTÇİ

Keyword(s):

Arabidopsis Thaliana ◽

Photosynthetic Pigments ◽

Growth Parameters ◽

Endophytic Bacterium ◽

Dry Weight ◽

Bacterial Populations ◽

Positive Effects ◽

Inactive Form ◽

Potential Possibility

The aim of this study was to analyze possible positive effects of putatively endophytic PGPB (PGB_invit), which was isolated from long-term in vitro cultured fraser photinia microshoots, on seed and 7-day old seedling stages of Arabidopsis thaliana. Seeds and in vitro-germinated seedlings were inoculated with 107 CFU/mL and 108 CFU/mL active (A) and inactive (I) endophytic bacterial populations along with their mix compositions (A+I) and suspended in MPYE broth together with their controls (untreated ones). 14 days old seedlings were evaluated for various plant growth parameters [i.e., shoot and root fresh weight (FW), shoot length (SL), shoot and root dry weight (DW), root length (RL) and photosynthetic pigments including chlorophyll a, b and carotenoids of plantlets] as well as endophytic and rhizospheric trait of bacteria. Positive effects of inactive and active bacterium on FW, DW and photosynthetic pigments for 7-day inoculated seedlings were recorded whereas an increase in photosynthetic contents for seed stage inoculations was observed. Rhizospheric and endophytic colonization of the bacteria was confirmed by PCR with the presence of virD1 gene, which is previously recorded to be existed in the plasmid of bacterium after inoculation. Overall, these results demonstrated that this peculiar putative endophytic bacterium being beneficial in active and even more useful in inactive form for A. thaliana when optimum conditions and concentrations are used. Moreover, presence of virD1 gene suggested its potential possibility to be used in bioengineering along with various other beneficial PGPR features as biofertilizer.

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Phosphorous Doping of Microcrystalline CVD Diamond Using Modified Conditions

MRS Proceedings ◽

10.1557/proc-1039-p17-01 ◽

2007 ◽

Vol 1039 ◽

Author(s):

Ken Haenen ◽

Andrada Lazea ◽

Vincent Mortet ◽

Jan D'Haen ◽

Peter Geithner ◽

...

Keyword(s):

Microwave Plasma ◽

Growth Parameters ◽

Chemical Vapor ◽

Polycrystalline Diamond ◽

Cvd Diamond ◽

Growth Conditions ◽

Diamond Surfaces ◽

Cvd Growth ◽

Oriented Polycrystalline ◽

Electron Back Scattered Diffraction

AbstractPhosphorous-doping of predominantly (110) oriented polycrystalline CVD diamond films is presented. Incorporation of phosphorous into the diamond grains was accomplished by using novel microwave plasma enhanced chemical vapor deposition (MW PE CVD) growth conditions. The substitutional nature of the phosphorous atom was confirmed by applying the quasi-steady-state photocurrent technique (PC) and cathodoluminescence (CL) measurements at low temperature. Topographical information and the relation between substrate and P-doped film grain orientation was obtained with scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The optimized growth parameters for P-doped layers on (110) oriented polycrystalline diamond differ substantially from the standard conditions reported in literature for P-doping of single crystalline (111) and (100) oriented diamond surfaces.

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