scholarly journals Serological and biochemical distinguishing of Pseudomonas syringae pathovars on peas

1999 ◽  
Vol 35 (No. 3) ◽  
pp. 79-84 ◽  
Author(s):  
I. Pánková ◽  
B. Kokošková
Keyword(s):  
Pseudomonas Syringae ◽  
Serological Test ◽  
Double Diffusion ◽  
Bacterial Cells ◽  
Serological Tests ◽  
Cross Absorption ◽  
Polyclonal Antisera ◽  
Pseudomonas Syringae Pathovars ◽  
High Level ◽  
Heterologous Antigens

Polyclonal antisera to detect and determine two related pathovars, Pseudomonas syringae pv. pisi and Pseudomonas syringae pv. syringae, were prepared Untreated bacterial cells, or fixed by formaldehyde or glutaraldehyde were used as antigens. After cross-absorption with heterologous antigens, antisera revealed a high level of specificity in slide agglutination, Ouchterlony gel double-diffusion and in DAS-ELISA and PTA-ELISA. Each of 14 P s. pisi prepared polyclonal antisera could detect and deter­ mine all strains of P s. pisi, regardless of race. PTA-ELISA was the most appropriate serological test to distinguish Pseudomonas syringae pathovars on peas. Most of the P s. pisi strains from foreign collections were in serological tests confirmed asP. s. pisi, while most of the Czech strains suspected as P s. pisi were determined as P s. syringae strains. The principal biochemical reaction, i.e., use of DL-homoserine as a carbon source to grow P s. pisi but not P s. syringae , was proved not to be sufficiently reliable to distinguish both pathovars.

scholarly journals The effect of serological screening for SARS-CoV-2 antibodies to participants’ attitudes and risk behaviour: a study on a tested population sample of industry workers in Split-Dalmatia County, Croatia

2020 ◽  
Author(s):  
Toni Ljubić ◽  
Ana Banovac ◽  
Ivan Buljan ◽  
Ivan Jerković ◽  
Željana Bašić ◽  
...  
Keyword(s):  
Serological Test ◽  
Population Sample ◽  
Risk Behaviour ◽  
Working Environment ◽  
Test Results ◽  
Serological Tests ◽  
Serological Screening ◽  
Protective Measures ◽  
Before And After ◽  
High Level

ABSTRACTRapid serological tests for SARS-CoV-2 antibodies have been questioned by scientists and the public because of unexplored effects of negative test results on behaviour and attitudes, that could lower the level of adherence to protective measures. Therefore, our study aimed to investigate the changes in personal attitudes and behaviour before and after negative serological test results for SARS-CoV-2 antibodies. We conducted a survey questionnaire on 200 industry workers (69% males and 31% females) that have been previously tested negative. The survey examined participants’ self-reported general attitudes towards COVID-19, sense of fear, as well as their behaviour related to protective measures before and after the testing. The participants perceived the disease as a severe health threat and acknowledged the protective measures as appropriate. They reported a high level of adherence to measures and low level of fear both before and after the testing. Although those indicators were statistically significantly reduced after the test (P < 0.004), they did not result in risk behaviour. Therefore, the serological tests are not an additional threat regarding the risk behaviour in an environment where protective measures are efficient. In contrast, they might contribute to reducing the fear in the society and working environment.

scholarly journals Development and Application of a Loop-Mediated Isothermal Amplification (LAMP) Assay for the Detection of Pseudomonas syringae Pathovars pisi and syringae

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 875
Author(s):  
Pragya Kant ◽  
Mario Fruzangohar ◽  
Rachel Mann ◽  
Brendan Rodoni ◽  
Grant Hollaway ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Lamp Assay ◽  
Laboratory Diagnosis ◽  
Isothermal Amplification ◽  
Field Pea ◽  
Bacterial Cells ◽  
Vegetable Crops ◽  
Closely Related Species ◽  
Loop Mediated Isothermal Amplification ◽  
Pseudomonas Syringae Pathovars

Pseudomonas syringae causes bacterial blight (BB) disease worldwide on economically important fruit and vegetable crops including field pea (Pisum sativum L.). The two pathovars responsible for BB in field pea are Pseudomonas syringae pathovar pisi (Psp) and syringae (Pss). In the field, both pathovars cause indistinguishable symptoms on field pea and require laboratory diagnosis to determine the causal pathovar. To aid in-field and laboratory diagnosis, accurate, and robust loop-mediated isothermal amplification (LAMP) assays for Psp and Pss were developed. The assays were able to detect Psp or Pss on live or heat-killed bacterial cells, plant exudates, seeds, and DNA extracts with no inhibitory effects. The two specific LAMP assays developed detected Psp and Pss accurately in less than 20 min and no cross-reaction was observed with 18 strains of closely related species of Pseudomonas syringae. Compared to the conventional PCR assays, the two LAMP assays were equally specific but have advantages of producing quicker and visual live results, enabling early detection and differentiation of Psp and Pss. Our results suggested a potential use of LAMP assays for laboratory testing and can be applied for in-field surveys.

Toxic Effect of 2-ethyl (bicyclo[2.2.1] heptane) on Bacterial Cells

2019 ◽  
Vol 35 (6) ◽  
pp. 67-72 ◽  
Author(s):  
I.V. Manukhov ◽  
L.S. Yaguzhinsky ◽  
M.V. Bermeshev ◽  
M.A. Zisman ◽  
V.G. Pevgov ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Atmospheric Oxygen ◽  
Inducible Promoter ◽  
Oxygen Species ◽  
Bacterial Cells ◽  
Unique Identifier ◽  
E Coli ◽  
Lux Biosensors ◽  
High Level ◽  
Ministry Of Higher Education

Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).

scholarly journals Seropositivity to canine tick-borne pathogens in a population of sick dogs in Italy

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jairo Alfonso Mendoza-Roldan ◽  
Giovanni Benelli ◽  
Marcos Antonio Bezerra-Santos ◽  
Viet-Linh Nguyen ◽  
Giuseppe Conte ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Serological Test ◽  
Control Strategies ◽  
Central Italy ◽  
Rickettsia Conorii ◽  
High Seroprevalence ◽  
The South ◽  
Serum Samples ◽  
Serological Tests ◽  
Distribution Maps

Abstract Background Canine vector-borne diseases (CVBDs) associated to ticks are among the most important health issues affecting dogs. In Italy, Ehrlichia canis, Anaplasma spp., Rickettsia conorii and Borrelia burgdorferi (s.l.) have been studied in both healthy canine populations and those clinically ill with suspected CVBDs. However, little information is currently available on the overall prevalence and distribution of these pathogens in the country. The aim of this study was to assess the prevalence and distribution of tick-borne pathogens (TBPs) in clinically suspect dogs from three Italian macro areas during a 15-year period (2006–2020). Methods A large dataset (n = 21,992) of serological test results for selected TBPs in three macro areas in Italy was analysed using a Chi-square test to evaluate the associations between the categorical factors (i.e. macro area, region, year, sex and age) and a standard logistic regression model (significance set at P = 0.05). Serological data were presented as annual and cumulative prevalence, and distribution maps of cumulative positive cases for TBPs were generated. Results Of the tested serum samples, 86.9% originated from northern (43.9%) and central (43%) Italy. The majority of the tests was requested for the diagnosis of E. canis (47%; n = 10,334), followed by Rickettsia spp. (35.1%; n = 7725), B. burgdorferi (s.l.) (11.6%; n = 2560) and Anaplasma spp. (6.2%; n = 1373). The highest serological exposure was recorded for B. burgdorferi (s.l.) (83.5%), followed by Rickettsia spp. (64.9%), Anaplasma spp. (39.8%) and E. canis (28.7%). The highest number of cumulative cases of Borrelia burgdorferi (s.l.) was recorded in samples from Tuscany, central Italy. Rickettsia spp. was more prevalent in the south and on the islands, particularly in dogs on Sicily older than 6 years, whereas Anaplasma spp. was more prevalent in the north and E. canis more prevalent in the south and on the islands. Conclusions The results of this study highlight the high seroprevalence and wide distribution of the four TBPs in dogs with clinically suspected CVBDs from the studied regions of Italy. The very high seroprevalence of B. burgdorferi (s.l.) exemplifies a limitation of this study, given the use of clinically suspect dogs and the possibility of cross-reactions when using serological tests. The present research provides updated and illustrative information on the seroprevalence and distribution of four key TBPs, and advocates for integrative control strategies for their prevention. Grapic abstract

Production and use of monoclonal antibodies for identification of Bradyrhizobium japonicum strains

1988 ◽  
Vol 34 (1) ◽  
pp. 88-92 ◽  
Author(s):  
D. Velez ◽  
J. D. Macmillan ◽  
L. Miller
Keyword(s):  
Monoclonal Antibodies ◽  
Bradyrhizobium Japonicum ◽  
Chemical Nature ◽  
Periodate Oxidation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Gram Negative ◽  
Polyclonal Antisera ◽  
Somatic Antigens

Thirteen murine hybridomas capable of producing monoclonal antibodies to somatic antigens on Bradyrhizobium japonicum were developed and an indirect enzyme-linked immunosorbent assay was used to test reactivity of the antibodies against 20 strains of B. japonicum. Although polyclonal antisera from mice immunized with strains of B. japonicum reacted with bacterial cells of all 20 strains, individual monoclonals were more specific. Some antibodies reacted with as few as 2 and one with as many as 11 strains. On the basis of reactivity with the set of 13 monoclonal antibodies, the 20 strains of B. japonicum could be divided arbitrarily into five groups. Three of five monoclonal antibodies tested reacted with bacteroids taken directly from soybean nodules. One monoclonal bound to cells of five species of Rhizobium, but none of the 13 reacted with gram-negative bacteria representing six other genera. Treatment of cells with reagents and heat indicated the chemical nature of the antigens to five of the monoclonals. Antigen reactive with one antibody was destroyed by periodate oxidation indicating that it was a polysaccharide. Two antigens were probably proteins as they could be digested by trypsin and denatured by heat. Two others were inactivated by all three treatments suggesting they were glycoproteins.

Viability and respiratory activity ofPseudomonas syringaecells starved in buffer

1995 ◽  
Vol 41 (4-5) ◽  
pp. 372-377 ◽  
Author(s):  
João P. S. Cabral
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Pseudomonas Syringae ◽  
Respiratory Activity ◽  
Bacterial Cells ◽  
Intact Cells ◽  
Rate Of Oxygen Consumption ◽  
Metabolic Activities ◽  
Different Levels ◽  
Number Of Cells

Pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. The number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. The results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. Starvation also resulted in a decrease in the rate of oxygen consumption with acetate, glycerol, and succinate, but at different levels. Whereas the respiration of acetate and glycerol decreased concomitantly with culturability, the respiration of succinate decreased to levels similar to the concentration of intact cells, suggesting that all intact particles respired the succinate, but only the culturable cells respired the acetate and glycerol. The results suggest that measuring the activity of the electron-transport system can overestimate the viability of starved bacterial cells, and that complex metabolic activities such as the respiration of acetate and glycerol are probably better suited for the evaluation of this parameter.Key words: Pseudomonas syringae, starvation, culturability, viability, respiration.

DIFFERENTIATION OF AGROPYRON MOSAIC, WHEAT STREAK MOSAIC, AND A HITHERTO UNRECOGNIZED HORDEUM MOSAIC VIRUS IN CANADA

1966 ◽  
Vol 44 (9) ◽  
pp. 1191-1208 ◽  
Author(s):  
J. T. Slykhuis ◽  
W. Bell
Keyword(s):  
Mosaic Virus ◽  
Avena Sativa ◽  
Systemic Infection ◽  
Triticum Aestivum L ◽  
Differential Centrifugation ◽  
Mild Strain ◽  
Serological Tests ◽  
Aceria Tulipae ◽  
Cross Absorption ◽  
Hordeum Jubatum

Agropyron mosaic virus (AMV) from Ontario and wheat streak mosaic virus (WSMV) from Alberta readily infected wheat (Triticum aestivum L.) causing mosaic symptoms that could be differentiated only when carefully compared. All isolates of AMV infected Agropyron repens (L.) Beauv. but not oats (Avena sativa L.). WSMV infected oats but not A. repens. Hordeum mosaic virus (HMV) from Alberta caused mottle rather than streak symptoms on wheat, rye, and other common hosts of WSMV, and did not infect A. repens, but, like AMV, it was not transmitted by Aceria tulipae (K.), the vector of WSMV. It infected Hordeum jubatum L., which is not susceptible to AMV or WSMV. It ranked between AMV and WSMV in longevity and tolerance to heat and pH. The particles were flexuous rods similar to those of WSMV, which appear less flexuous and slightly shorter than particles of AMV.The temperatures at which the viruses multiplied and caused symptoms on wheat ranged from 15° to 33 °C for WSMV and 10° to 30° for AMV. HMV multiplied at all temperatures from 10° to 33 °C but caused symptoms only at 10° to 30 °C.Specific antisera were prepared by partially purifying the viruses by differential centrifugation of juice from diseased wheat, emulsifying the juice with adjuvant, then injecting rabbits intramuscularly. The precipitation titers against their homologous viruses were 1/640, 1/1280, and 1/1280 for the WSMV, AMV, and HMV antisera respectively. The WSMV antiserum did not react with the heterologous viruses, but two HMV antisera had a precipitation titer of 1/16 against AMV, and an AMV antiserum had a titer of 1/10 againt WSMV. Cross absorption of each of the antisera with the heterologous viruses did not reduce the titers against the homologous viruses.The infection of wheat with a mild strain of any of the three viruses protected against later infection by a severe strain of the same virus. Both AMV and HMV were synergistic in combination with WSMV. Serological tests demonstrated that both AMV and HMV multiplied in wheat simultaneously inoculated with both viruses, but systemic infection with either virus protected the plants against later infection by the other.Despite general similarities in physical characteristics and effects on wheat, specific differences in other characteristics show that AMV, HMV, and WSMV are sufficiently different to be designated as different viruses rather than closely related strains of one virus.

scholarly journals Effects of atmospheric conditions on ice nucleation activity of <i>Pseudomonas</i>

2012 ◽  
Vol 12 (22) ◽  
pp. 10667-10677 ◽  
Author(s):  
E. Attard ◽  
H. Yang ◽  
A.-M. Delort ◽  
P. Amato ◽  
U. Pöschl ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Acidic Ph ◽  
Bacterial Cells ◽  
Atmospheric Conditions ◽  
Ice Nucleation Protein ◽  
Ice Melt ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

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