scholarly journals Spatial-Temporal and Quantitative Analysis of Growth and EPS I Production by Ralstonia solanacearum in Resistant and Susceptible Tomato Cultivars

1999 ◽  
Vol 89 (12) ◽  
pp. 1233-1239 ◽  
Author(s):  
J. A. McGarvey ◽  
T. P. Denny ◽  
M. A. Schell
Keyword(s):  
Ralstonia Solanacearum ◽  
Antimicrobial Activities ◽  
Enzyme Linked Immunosorbent Assay ◽  
Vascular Bundles ◽  
Susceptible Cultivar ◽  
Bacterial Populations ◽  
Resistant Cultivars ◽  
Cell Densities ◽  
Almost All ◽  
Susceptible Tomato

One susceptible and two resistant cultivars of tomato were tested for differences in infection by Ralstonia solanacearum and for the subsequent multiplication, colonization, and production of the wilt-inducing virulence factor, exopolysaccharide I (EPS I). Bacterial ingress into the taproot was fastest in the susceptible cv. Marion, followed by the resistant cvs. L285 (fivefold slower) and Hawaii 7996 (15-fold slower). Once inside the taproot, R. solanacearum colonized, to some extent, almost all regions of the resistant and susceptible plants. However, colonization occurred sooner in the susceptible than in the resistant cultivars, as measured by viablecell counts of bacteria in the midstems. Rates of multiplication and maximum bacterial cell densities were also greater in the susceptible than in the resistant cultivars. Growth experiments utilizing xylem fluid from infected and uninfected plants indicated that neither antimicrobial activities nor reduced levels of growth-supporting nutrients in the xylem fluids were responsible for the reduced bacterial multiplication in the resistant cultivars. Quantification of EPS I in the infected plants, using an enzyme-linked immunosorbent assay, revealed that the bacterial populations in the susceptible cultivar produced greater amounts of EPS I per plant than those in the resistant cultivars. Immunofluorescence microscopy using antibodies against either EPS I or R. solanacearum cells revealed that bacteria and EPS I were distributed throughout the vascular bundles and intercellular spaces of the pith in the susceptible cultivar, whereas in the resistant cultivars, bacteria and EPS I were restricted to the vascular tissues.

First Detection of Tobacco Mosaic Virus in Tobacco Fields in Northern Lebanon

2020 ◽  
Vol 20 ◽  
Author(s):  
Rami Obeid ◽  
Elias Wehbe ◽  
Mohamad Rima ◽  
Mohammad Kabara ◽  
Romeo Al Bersaoui ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Viral Genome ◽  
Virus Genome ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Family ◽  
Crop Fields ◽  
Wide Range ◽  
Almost All ◽  
Das Elisa

Background: Tobacco mosaic virus (TMV) is the most known virus in the plant mosaic virus family and is able to infect a wide range of crops, in particularly tobacco, causing a production loss. Objectives: Herein, and for the first time in Lebanon, we investigated the presence of TMV infection in crops by analyzing 88 samples of tobacco, tomato, cucumber and pepper collected from different regions in North Lebanon. Methods: Double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), revealed a potential TMV infection of four tobacco samples out of 88 crops samples collected. However, no tomato, cucumber and pepper samples were infected. The TMV+ tobacco samples were then extensively analyzed by RT-PCR to detect viral RNA using different primers covering all the viral genome. Results and Discussion: PCR results confirmed those of DAS-ELISA showing TMV infection of four tobacco samples collected from three crop fields of North Lebanon. In only one of four TMV+ samples, we were able to amplify almost all the regions of viral genome, suggesting possible mutations in the virus genome or an infection with a new, not yet identified, TMV strain. Conclusion: Our study is the first in Lebanon revealing TMV infection in crop fields, and highlighting the danger that may affect the future of agriculture.

scholarly journals Synthesis and antimicrobial activities of novel n-substituted 8-(1-alkyl/alkylsulphonyl/alkoxycarbonyl-benzimidazol-2-ylmethoxy)-5-chloroquinolines

2011 ◽  
Vol 76 (9) ◽  
pp. 1199-1206 ◽  
Author(s):  
Raju Chaudhari ◽  
Sahebrao Rindhe
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Nitrogen Heterocycles ◽  
Antimicrobial Activities ◽  
Mass Spectral Data ◽  
Antifungal Activities ◽  
Mass Spectral ◽  
Electrophilic Reagents ◽  
Almost All ◽  
And Staphylococcus Aureus

Herein the synthesis of a series of novel 8-(1- alkyl/alkylsulphonyl/alkoxycarbonyl-benzimidazol-2-ylmethoxy)-5- chloroquinoline derivatives is reported. These derivatives were prepared by the condensation of o-phenylenediamine with [(5-chloroquinolin-8- yl)oxy]acetic acid, followed by substitution at nitrogen with different electrophilic reagents in presence of an appropriate base to give a series of nitrogen heterocycles containing the benzimidazole and quinoline nuclei. The structures of the compounds were confirmed based on 1H-NMR, 13CNMR, IR and mass spectral data. Almost all the compounds exhibited promising antibacterial activity against Salmonella typhimurium and Staphylococcus aureus. Some of the compounds showed good antifungal activities against Aspergillus niger but the antifungal activities against Candida albicans were disappointing.

scholarly journals NtRNF217, Encoding a Putative RBR E3 Ligase Protein of Nicotiana tabacum, Plays an Important Role in the Regulation of Resistance to Ralstonia solanacearum Infection

2021 ◽  
Vol 22 (11) ◽  
pp. 5507
Author(s):  
Ying Liu ◽  
Yuanman Tang ◽  
Xi Tan ◽  
Wei Ding
Keyword(s):  
Nicotiana Tabacum ◽  
Ralstonia Solanacearum ◽  
Plant Immunity ◽  
E3 Ligase ◽  
Marker Genes ◽  
Susceptible Cultivar ◽  
Wild Type ◽  
Disease Symptoms ◽  
Short Time ◽  
Resistance To Ralstonia Solanacearum

E3 ubiquitin ligases, the most important part of the ubiquitination process, participate in various processes of plant immune response. RBR E3 ligase is one of the E3 family members, but its functions in plant immunity are still little known. NtRNF217 is a RBR E3 ligase in tobacco based on the sequence analysis. To assess roles of NtRNF217 in tobacco responding to Ralstonia solanacearum, overexpression experiments in Nicotiana tabacum (Yunyan 87, a susceptible cultivar) were performed. The results illuminated that NtRNF217-overexpressed tobacco significantly reduced multiplication of R. solanacearum and inhibited the development of disease symptoms compared with wild-type plants. The accumulation of H2O2 and O2− in NtRNF217-OE plants was significantly higher than that in WT-Yunyan87 plants after pathogen inoculation. The activities of CAT and SOD also increased rapidly in a short time after R. solanacearum inoculation in NtRNF217-OE plants. What is more, overexpression of NtRNF217 enhanced the transcript levels of defense-related marker genes, such as NtEFE26, NtACC Oxidase, NtHIN1, NtHSR201, and NtSOD1 in NtRNF217-OE plants after R. solanacearum inoculation. The results suggested that NtRNF217 played an important role in regulating the expression of defense-related genes and the antioxidant enzymes, which resulted in resistance to R. solanacearum infection.

scholarly journals Biofilm and productivity-associated community changes in serial-transfer experiments in heterogeneous liquid microcosms

2020 ◽  
Author(s):  
Robyn Jerdan ◽  
Emily Donaldson ◽  
Scott Cameron ◽  
Andrew Spiers
Keyword(s):  
Liquid Column ◽  
Community Diversity ◽  
Ecological Interactions ◽  
Community Members ◽  
Serial Transfer ◽  
Lower Region ◽  
Fitness Advantage ◽  
Cell Densities ◽  
Almost All ◽  
Phenotypic Shift

<p>Static incubation of liquid microcosms results in a physically heterogeneous environment, where depletion of O<sub>2 </sub>in the lower region creates a relatively high-O<sub>2 </sub>niche directly below the air-liquid (A-L) interface. This has been investigated using the model bacterium <em>Pseudomonas fluorescens</em> SBW25 and the biofilm-forming adaptive mutant known as the Wrinkly Spreader. In this system, colonisation of the A-L interface by the Wrinkly Spreader provides a fitness advantage over non-biofilm-forming competitors, including the ancestral SBW25, due to better access to O<sub>2</sub> in an otherwise O<sub>2</sub>-growth limiting environment. Our current research seeks to understand how the ecological interactions of this simple system applies in more complex communities, where biofilms can be produced by multiple competing or co-operative strains and the low-O<sub>2</sub> region colonised by a range of strains capable of micro-aerobic growth. Here we report the effect of selection on the productivity of A-L interface biofilm-forming communities initiated by soil-wash (SW) inocula, which were serially transferred across ten microcosms and sixty days with mixed-community or biofilm-only samples. Initial analysis of the serial transfer experiments shows a decrease in community productivity which is explained by the accumulation of toxic metabolites, though small increases in community biofilm strength and attachment were also observed. Isolate-level analysis revealed a decrease in community diversity and a biofilm-associated phenotypic shift between the SW inocula and final-transfer communities, and these changes provide evidence of selection within our system.</p> <p>Cell-localisation experiments confirm enrichment at the top of the liquid column in the high-O<sub>2</sub> region, but also show high cell densities in the low-O<sub>2</sub> region, even within the biofilm-only final-transfer communities. Samples taken from the biofilm and lower region of these communities were able to re-colonise both in fresh microcosms, indicating that community members were capable of migration within the liquid column. Despite the over-all decrease seen in community productivity in the serial transfer experiments, we suggest that communities maximised productivity by colonising both regions of the liquid column, with a resource trade-off between fast growth in the highly competitive high-O<sub>2 </sub>region and slower growth in the less-competitive low-O<sub>2</sub> region. Many isolates from the final-transfer communities could occupy both regions and were capable of migration, with almost all isolates capable of flagella-mediated motility, and we interpret this ability to move between regions as a fitness advantage in A-L interface biofilm-forming communities. Although we have not been able to test this directly using the final-transfer communities or isolates, we have been able to demonstrate a fitness advantage in the less complex <em>P. fluorescens</em> SBW25 system, where biofilm-forming mutants capable of colonising both regions had a greater competitive fitness advantage over those with a poor ability to colonise the liquid column.</p>

scholarly journals Chemical Composition and Biological Activities of Oregano Essential Oil and Its Fractions Obtained by Vacuum Distillation

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1904 ◽  
Author(s):  
Magdalena de J. Rostro-Alanis ◽  
Juan Báez-González ◽  
Cynthia Torres-Alvarez ◽  
Roberto Parra-Saldívar ◽  
José Rodriguez-Rodriguez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Vacuum Distillation ◽  
Biological Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Antimicrobial Activities ◽  
Gas Chromatography Mass Spectrometry ◽  
Oregano Essential Oil ◽  
Almost All

Oregano (Poliomintha longiflora) essential oil (Ooil) is a product of high commercial value and many applications, including chemotherapy. Aiming to achieve the best use of this resource, the present study focuses on the characterization of separated fractions of Ooil by fractional vacuum distillation at low pressure. Four fractions (F1–F4) and undistilled oil (Unoil) were separated from Ooil and analyzed for their chemical composition and biological activities, such as antioxidant and antimicrobial activities. Gas chromatography–mass spectrometry shows differences in the composition among the fractions and Ooil. The amount of monoterpenes oxygenated (MO), sesquiterpenes hydrocarbon (SeH) and monoterpenes hydrocarbon (MH) varied between the fractions in ranges of 1.51–68.08, 3.31–25.12 and 1.91–97.75%, respectively. The major concentrations of MO and SeH were observed in F4 and Unoil. On the other hand, the highest concentrations of MH were found in F1 and F2, while the lowest were in F4 and Unoil. These results were correlated with the biological activity. Free-radical scavenging activity varied among fractions, with F4 and Unoil showing the highest activity. The antimicrobial test showed that F4 and Unoil had the highest activity in almost all cases. The correlation between the variables studied in the different fractions allows the definition of the particular properties for each one of them.

scholarly journals Antifungal Drugs Influence Neutrophil Effector Functions

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Frederic Ries ◽  
Astrid Alflen ◽  
Pamela Aranda Lopez ◽  
Hendrik Beckert ◽  
Matthias Theobald ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Antifungal Drugs ◽  
Polymorphonuclear Neutrophils ◽  
Enzyme Linked Immunosorbent Assay ◽  
Activation Markers ◽  
Effector Functions ◽  
Enhanced Expression ◽  
Almost All

ABSTRACTThere is a growing body of evidence for immunomodulatory side effects of antifungal agents on different immune cells, e.g., T cells. Therefore, the aim of our study was to clarify these interactions with regard to the effector functions of polymorphonuclear neutrophils (PMN). Human PMN were preincubated with fluconazole (FLC), voriconazole (VRC), posaconazole (POS), isavuconazole (ISA), caspofungin (CAS), micafungin (MFG), conventional amphotericin B (AMB), and liposomal amphotericin B (LAMB). PMN then were analyzed by flow cytometry for activation, degranulation, and phagocytosis and by dichlorofluorescein assay to detect reactive oxygen species (ROS). Additionally, interleukin-8 (IL-8) release was measured by enzyme-linked immunosorbent assay. POS led to enhanced activation, degranulation, and generation of ROS, whereas IL-8 release was reduced. In contrast, ISA-pretreated PMN showed decreased activation signaling, impaired degranulation, and lower generation of ROS. MFG caused enhanced expression of activation markers but impaired degranulation, phagocytosis, generation of ROS, and IL-8 release. CAS showed increased phagocytosis, whereas degranulation and generation of ROS were reduced. AMB led to activation of almost all effector functions besides impaired phagocytosis, whereas LAMB did not alter any effector functions. Independent from class, antifungal agents show variable influence on neutrophil effector functionsin vitro. Whether this is clinically relevant needs to be clarified.

scholarly journals Metabolic Responses of Lactobacillus plantarum Strains during Fermentation and Storage of Vegetable and Fruit Juices

2014 ◽  
Vol 80 (7) ◽  
pp. 2206-2215 ◽  
Author(s):  
P. Filannino ◽  
G. Cardinali ◽  
C. G. Rizzello ◽  
S. Buchin ◽  
M. De Angelis ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactobacillus Plantarum ◽  
Malic Acid ◽  
Gamma Aminobutyric Acid ◽  
Content Type ◽  
Growth And Survival ◽  
The Matrix ◽  
Cell Densities ◽  
Almost All ◽  
And Storage

ABSTRACTStrains ofLactobacillus plantarumwere grown and stored in cherry (ChJ), pineapple (PJ), carrot (CJ), and tomato (TJ) juices to mimic the chemical composition of the respective matrices. Wheat flour hydrolysate (WFH), whey milk (W), and MRS broth were also used as representatives of other ecosystems. The growth rates and cell densities ofL. plantarumstrains during fermentation (24 h at 30°C) and storage (21 days at 4°C) differed only in part, being mainly influenced by the matrix. ChJ and PJ were the most stressful juices for growth and survival. Overall, the growth in juices was negatively correlated with the initial concentration of malic acid and carbohydrates. The consumption of malic acid was noticeable for all juices, but mainly during fermentation and storage of ChJ. Decreases of branched-chain amino acids (BCAA)—with the concomitant increase of their respective branched alcohols—and His and increases of Glu and gamma-aminobutyric acid (GABA) were the main traits of the catabolism of free amino acids (FAA), which were mainly evident under less acidic conditions (CJ and TJ). The increase of Tyr was found only during storage of ChJ. Some aldehydes (e.g., 3-methyl-butanal) were reduced to the corresponding alcohols (e.g., 3-methyl-1-butanol). After both fermentation and storage, acetic acid increased in all fermented juices, which implied the activation of the acetate kinase route. Diacetyl was the ketone found at the highest level, and butyric acid increased in almost all fermented juices. Data were processed through multidimensional statistical analyses. Except for CJ, the juices (mainly ChJ) seemed to induce specific metabolic traits, which differed in part among the strains. This study provided more in-depth knowledge on the metabolic mechanisms of growth and maintenance ofL. plantarumin vegetable and fruit habitats, which also provided helpful information to select the most suitable starters for fermentation of targeted matrices.

scholarly journals Seasonal Variation of Ralstonia solanacearum Biovar 2 Populations in a Spanish River: Recovery of Stressed Cells at Low Temperatures

2005 ◽  
Vol 71 (1) ◽  
pp. 140-148 ◽  
Author(s):  
Paola Caruso ◽  
Jose Luis Palomo ◽  
Edson Bertolini ◽  
Bel�n �lvarez ◽  
Mar�a M. L�pez ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Water Samples ◽  
Low Temperatures ◽  
Most Probable Number ◽  
Enzyme Linked Immunosorbent Assay ◽  
Probable Number ◽  
Solid Media ◽  
Nonculturable State ◽  
Enrichment Protocol ◽  
Stressed Cells

ABSTRACT The presence of Ralstonia solanacearum biovar 2 in the watercourses of European countries is increasing, but little is known about its ecology in aquatic habitats. The detection of this pathogen in 2000 in one Spanish river led us to study its population density at different locations on the river over a period of 3 years. During 2000 and 2001, the pathogen was recovered at low densities (10 to 80 CFU/ml) by direct plating on modified SMSA agar from water samples at 14�C or higher, but its isolation was usually unsuccessful at temperatures below 9�C. To monitor the pathogen's abundance in winter, we used two liquid selective media for enrichment (at 29 and 35�C) and compared them by using spiked river water samples: modified Wilbrink broth (MWB) was more efficient than modified SMSA broth for double-antibody-sandwich indirect enzyme-linked immunosorbent assay (DASI-ELISA) detection of R. solanacearum. Enrichment in MWB at both temperatures allowed us to recover R. solanacearum cells that were nonculturable on solid media up to 25 days after their entry into the viable but nonculturable state. When we applied this technique to water samples during the cold months of 2001 and 2002, we obtained the best detection results by the most-probable-number method after enrichment at 35�C with MWB. The enrichment protocol was combined with DASI-ELISA and validated by Co-PCR to detect both naturally and artificially starved and cold-stressed cells in water, which were still infective. Overall, the data from this study demonstrate the effects of temperature variation on the population and culturability of R. solanacearum cells on solid media and their survival at low temperatures.

Infection of faba beans by Sclerotinia trifoliorum

2004 ◽  
Vol 84 (4) ◽  
pp. 1235-1237 ◽  
Author(s):  
A. S. Lithourgidis
Keyword(s):  
Vicia Faba ◽  
Artificial Inoculation ◽  
Susceptible Cultivar ◽  
Sclerotinia Trifoliorum ◽  
Fungus Infection ◽  
Vicia Narbonensis ◽  
Vicia Faba L ◽  
Resistant Population ◽  
Faba Beans ◽  
Almost All

The mode of penetration and the incubation time of Sclerotinia trifoliorum Eriks. were studied in one susceptible (Polycarpe) and one resistant (A-90) cultivar of faba beans (Vicia faba L.), and in one resistant population (A-207) of Vicia narbonensis L., after artificial inoculation in a growth chamber. The fungus penetrated almost all infected plants through the stomata (>96%). In the susceptible cultivar, symptoms of fungus infection appeared 10 h after artificial inoculation, whereas in the resistant cultivar and in the resistant population symptoms appeared after 22 and 16 h, respectively. Key words: Incubation, pathogenesis, penetration, Vicia faba L., Vicia narbonensis L.

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