Expression of resistance in bean pods to an incompatible isolate of Pseudomonas syringae

1977 ◽  
Vol 55 (15) ◽  
pp. 2043-2052 ◽  
Author(s):  
D. M. Webster ◽  
L. Sequeira
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Growth ◽  
Ethanolic Extract ◽  
Fresh Weight ◽  
Inoculum Level ◽  
Bacterial Populations ◽  
Progressive Decline ◽  
High Inoculum ◽  
Inhibitory Compounds ◽  
Extract Fraction

Isolates of Pseudomonas syringae from hairy vetch were either virulent (compatible) or avirulent (incompatible) to bean. When bean pods were injected at high inoculum levels (5 × 107 cells/ml), both compatible and incompatible isolates multiplied rapidly and caused water-soaking of injected tissues; populations of both isolates were similar at the end of log phase. Lesions caused by the incompatible isolate turned brown by 3 days after inoculation and did not expand; those caused by the compatible isolate remained water-soaked and expanded into the adjoining, noninoculated tissues. At low inoculum levels (5 × 104 cells/ml), the compatible isolate exhibited the same pattern of multiplication and lesion development as at the high inoculum level. The incompatible isolate, on the other hand, caused necrotic flecking within the injected area by 24 h, and these small lesions remained limited. Appearance of the necrotic flecks was correlated with a progressive decline in bacterial populations; after5 days, the population of incompatible bacteria was about a hundredfold lower than that of compatible ones. Populations of incompatible bacteria within and between the necrotic flecks declined rapidly, indicating the potential accumulation of inhibitors of bacterial growth as a result of an inducible resistance mechanism.The phytoalexin phaseollin reached 280 μg/g fresh weight by 3 days after inoculation of bean pods with incompatible bacteria. However, this compound was not involved in resistance. Neither compatible nor incompatible isolates of the bacterium were significantly inhibited when grown in a medium saturated with phaseollin. When other antibiotic substances in plant extracts were sought, substantial amounts of inhibitory compounds were detected only in the ethanolic extract (fraction soluble in ethyl acetate) of pods previously inoculated with an incompatible isolate of P. syringae. Only low levels of inhibition were obtained from identical extracts of uninfected pods or from pods inoculated with a compatible isolate of P. syringae. Bacterial growth was completely prevented in a bean infusion medium containing 1 g fresh weight equivalent of pod tissue challenged with the incompatible isolate. The active compound(s) was nonfluorescent, had a UV absorption maximum at 286 nm, and gave a positive reaction with reagents for phenolic compounds.

scholarly journals Heterogeneous ceramide distributions alter spatially resolved growth of Staphylococcus aureus on human stratum corneum

2018 ◽  
Vol 15 (141) ◽  
pp. 20170848 ◽  
Author(s):  
Joseph M. Cleary ◽  
Zachary W. Lipsky ◽  
Minyoung Kim ◽  
Cláudia N. H. Marques ◽  
Guy K. German
Keyword(s):  
Staphylococcus Aureus ◽  
Stratum Corneum ◽  
Bacterial Growth ◽  
Disease Transmission ◽  
Bacterial Species ◽  
Causal Link ◽  
Bacterial Populations ◽  
Human Stratum Corneum ◽  
Spatially Resolved ◽  
Skin Cleansing

Contemporary studies have revealed dramatic changes in the diversity of bacterial microbiota between healthy and diseased skin. However, the prevailing use of swabs to extract the microorganisms has meant that only population ‘snapshots’ are obtained, and all spatially resolved information of bacterial growth is lost. Here we report on the temporospatial growth of Staphylococcus aureus on the surface of the human stratum corneum (SC); the outermost layer of skin. This bacterial species dominates bacterial populations on skin with atopic dermatitis (AD). We first establish that the distribution of ceramides naturally present in the SC is heterogeneous, and correlates with the tissue's structural topography. This distribution subsequently impacts the growth of bacterial biofilms. In the SC retaining healthy ceramide concentrations, biofilms exhibit no spatial preference for growth. By contrast, a depletion of ceramides consistent with reductions known to occur with AD enables S. aureus to use the patterned network of topographical canyons as a conduit for growth. The ability of ceramides to govern bacterial growth is confirmed using a topographical skin canyon analogue coated with the ceramide subcomponent d -sphingosine. Our work appears to explain the causal link between ceramide depletion and increased S. aureus populations that is observed in AD. It may also provide insight into disease transmission as well as improving pre-operative skin cleansing techniques.

scholarly journals Sciadopitys verticillata Resin: Volatile Components and Impact on Plant Pathogenic and Foodborne Bacteria

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3767
Author(s):  
David I. Yates ◽  
Bonnie H. Ownley ◽  
Nicole Labbé ◽  
Joseph J. Bozell ◽  
William E. Klingeman ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Foodborne Pathogens ◽  
Antimicrobial Properties ◽  
Principal Component ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Components ◽  
Sample Treatment ◽  
Bacterial Populations ◽  
Sciadopitys Verticillata ◽  
The Impact

Sciadopitys verticillata (Sv) produces a white, sticky, latex-like resin with antimicrobial properties. The aims of this research were to evaluate the effects of this resin (Sv resin) on bacterial populations and to determine the impact of its primary volatile components on bioactivity. The impact of sample treatment on chemical composition of Sv resin was analyzed using Fourier transform infrared spectroscopy (FTIR) coupled with principal component analysis. The presence and concentration of volatiles in lyophilized resin were determined using gas chromatography/mass spectrometry (GC/MS). Changes in bacterial population counts due to treatment with resin or its primary volatile components were monitored. Autoclaving of the samples did not affect the FTIR spectra of Sv resin; however, lyophilization altered spectra, mainly in the CH and C=O regions. Three primary bioactive compounds that constituted >90% of volatiles (1R-α-pinene, tricyclene, and β-pinene) were identified in Sv resin. Autoclaved resin impacted bacterial growth. The resin was stimulatory for some plant and foodborne pathogens (Pseudomonas fluorescens, P. syringae, and Xanthomonas perforans) and antimicrobial for others (Escherichia coli, Bacillus cereus, Agrobacterium tumefaciens, and Erwinia amylovora). Treatment with either 1R-α-pinene or β-pinene reduced B. cereus population growth less than did autoclaved resin. The complex resin likely contains additional antimicrobial compounds that act synergistically to inhibit bacterial growth.

scholarly journals The Effect of Wounding, Temperature, and Inoculum on the Development of Pink Rot of Potatoes Caused by Phytophthora erythroseptica

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1327-1333 ◽  
Author(s):  
B. Salas ◽  
R. W. Stack ◽  
G. A. Secor ◽  
N. C. Gudmestad
Keyword(s):  
Infection Risk ◽  
Infected Tuber ◽  
Tuber Tissue ◽  
Inoculum Level ◽  
Inoculum Sources ◽  
Pink Rot ◽  
High Inoculum ◽  
Phytophthora Erythroseptica ◽  
Laboratory Cultures ◽  
Potential Impact

The effect of wounding, temperature, and inoculum on the development of pink rot caused by Phytophthora erythroseptica, was studied for its potential impact on postharvest infection. Tissue plugs cut from pink rot infected tubers and plugs of similar size from laboratory cultures of the pathogen were highly effective inoculum sources on wounded tubers. Severe wounding, temperatures of 15 to 25°C, and high inoculum density affected the infection risk. Regardless of source or amount of inoculum, any degree of wounding greatly increased incidence of infection of tubers by P. erythroseptica. Infections in unwounded tubers started at 15°C, whereas in wounded tubers infection started at 10°C. Incidence of pink rot was high when two or three of the factors (severe wounding, high temperature, high inoculum level) were favorable. Incidence of pink rot was intermediate when only one factor was favorable. Incidence of pink rot was low or absent without a favorable factor (no wounding, low temperature, and low inoculum), Since infected tuber tissue may serve as potential inoculum source for postharvest infection of tubers by P. erythroseptica, the removal of pink rot infected tubers at harvest is desirable. Avoidance of wounding and rapid cooling of storage bins to 10°C may also help control pink rot.

scholarly journals The growth of bacterial colonies and their viable population

1947 ◽  
Vol 45 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Anna Mayr-Harting
Keyword(s):  
Bacterial Growth ◽  
Bacterial Populations ◽  
Fluid Media ◽  
Viable Population

The numerical aspects of bacterial growth have hitherto been investigated chiefly in fluid media and the laws governing the development of bacterial populations in fluid cultures are known in some detail.

scholarly journals Holdover Inoculum of Pseudomonas syringae pv. alisalensis from Broccoli Raab Causes Disease in Subsequent Plantings

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1077-1084 ◽  
Author(s):  
N. A. Cintas ◽  
S. T. Koike ◽  
R. A. Bunch ◽  
C. T. Bull
Keyword(s):  
Pseudomonas Syringae ◽  
Brassica Rapa ◽  
Bacterial Blight ◽  
Laboratory Tests ◽  
Bacterial Population ◽  
Disease Incidence ◽  
Untreated Soil ◽  
Bacterial Populations ◽  
Field Soils ◽  
Over Time

Uniform plots of broccoli raab (Brassica rapa subsp. rapa) seedlings were inoculated with a rifampicin-resistant strain of Pseudomonas syringae pv. alisalensis, the causal agent of bacterial blight on crucifers, resulting in 100% disease incidence in mature plants. Diseased plants were incorporated into the soil at maturity and smaller replicated plots were replanted at various times after incorporation. Rifampicin-resistant fluorescent pseudomonads with rep-PCR profiles identical to P. syringae pv. alisalensis were isolated from lesions on plants grown in soil into which the first diseased crop was incorporated. Disease incidence declined in mature plants as the length of time between incorporation of the first planting and seeding of the replanted plots increased. Bacterial population levels in soil decreased over time and bacteria were no longer detectable 3 weeks after incorporation of the diseased crop. In laboratory tests, population levels of P. syringae pv. alisalensis decreased in untreated soil but not in autoclaved soil. Greenhouse studies demonstrated a direct correlation between population levels of P. syringae pv. alisalensis applied to soil and disease incidence in seedlings. However, the decline in bacterial populations in field soils did not wholly account for the decline in disease incidence with subsequent plantings.

scholarly journals In vitro antioxidant activity of Psidium guajava Linn. by using ethanolic extract fraction of leaves and bark

2018 ◽  
Vol 02 (01) ◽  
Author(s):  
Subba Rao Ch ◽  
Arun Kumar S ◽  
Javvad F Ali ◽  
Priyadarshini P ◽  
Hinduja M ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ethanolic Extract ◽  
Psidium Guajava ◽  
Extract Fraction ◽  
In Vitro Antioxidant Activity

CANADIAN WILTSHIRE BACON: XVIII. EFFECT OF TEMPERATURE AND BACTERIAL GROWTH ON NITRITE CONTENT

1941 ◽  
Vol 19d (3) ◽  
pp. 104-111
Author(s):  
W. Harold White ◽  
N. E. Gibbons
Keyword(s):  
Bacterial Growth ◽  
Effect Of Temperature ◽  
Bacterial Populations ◽  
Nitrite Content

Samples of bacon, with bacterial populations adjusted to two levels, were held at temperatures of 4°, 21°, 38°, and 55 °C. for 20, 40, 80, and 160 hr. Both the total number of organisms and the number capable of reducing nitrate to nitrite were significantly correlated with the nitrite content. Furthermore, the samples adjusted to the high bacterial level usually contained more nitrite after treatment than those from the same hog but containing fewer bacteria. The increase in nitrite, observed here and previously, at temperatures below 55 °C., is attributable primarily to bacterial growth and not to enzymes or other constituents of the bacon.

scholarly journals Green propolis ethanolic extract in bean plant protection against bacterial diseases

2019 ◽  
Vol 49 (6) ◽  
Author(s):  
Jonas Marcelo Jaski ◽  
Fabio Junior Telaxka ◽  
Gabriela Silva Moura ◽  
Gilmar Franzener
Keyword(s):  
Antimicrobial Activity ◽  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Phenylalanine Ammonia Lyase ◽  
Plant Protection ◽  
Ethanolic Extract ◽  
Systemic Effect ◽  
Bacterial Diseases ◽  
Bean Plants ◽  
Maximum Activation

ABSTRACT: The aim of this study was to evaluate the ethanolic extract of green propolis (EEP) in the protection of common bean plants against two main bacterial cultures, bacterial blight (Xanthomonas axonopodis pv. phaseoli) and wildfire (Pseudomonas syringae pv. tabaci). Experiments on antimicrobial activity were performed, inducing phytoalexins, defense-related enzymes, and disease severity, under concentrations of 0, 0.5, 1.0, 2.5, and 5.0%. The EEP presented antimicrobial activity on both phytobacteria, causing a decrease in their development. It has also promoted a linear accumulation of phaseolin in bean hypocotyls according to the EEP concentration used. There was a reduction in the lesion area, which was caused by bacterial blight on bean leaves treated with EEP, and local and systemic effect were observed. Polyphenoloxidase was activated with 5% EEP, reaching the maximum activation time 62.5 h after application. An increase was observed in the activity of phenylalanine ammonia-lyase in plants treated with EEP, with local and systemic effect. Results indicated the potential of EEP in the control of these diseases.

Effects of smectite clay on biofilm formation by microorganisms

Biofilms ◽  
2006 ◽  
Vol 3 (1) ◽  
pp. 47-54 ◽  
Author(s):  
A. Alimova ◽  
M. Roberts ◽  
A. Katz ◽  
E. Rudolph ◽  
J. C. Steiner ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Biofilm Formation ◽  
Dust Particles ◽  
Smectite Clay ◽  
Bacterial Populations ◽  
Clay Particles ◽  
Smectite Clays ◽  
Aerosol Dust ◽  
Clay Aggregates

ABSTRACTWe have investigated the role of smectite clay particles in biofilm formation by several different species of bacteria (Pseudomonas syringae, Escherichia coli,Staphylococcus aureusandBacillus subtilis). We observed that the presence of clay particles enhances the formation of biofilms and, after 24 h, the bacterial populations in the clay mixtures were greater than the respective populations in media without clay. Smectite-bearing clay slurries uniformly develop bacteria–clay aggregates with a substantial biofilm component within 24 h, while the exclusively bacterial suspensions do not develop any observable biofilm component. The biofilm–clay aggregates vary in size from tens of micrometers to several millimeters. Biofilm formation was evaluated by phase contrast microscopy and fluorescence staining. Biofilm promotion by smectite clays may indicate the importance of transport of bacteria by aerosol dust particles.

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