scholarly journals Severity assessment in the Nicotiana tabacum-Xylella fastidiosa subsp. pauca pathosystem: design and inter-laboratory validation of a standard area diagram

2020 ◽  
Author(s):  
Willian Eduardo Lino Pereira ◽  
Sheila Andrade ◽  
Emerson Medeiros Del Ponte ◽  
Mariana Bossi Esteves ◽  
Maria Cristina Canale ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Xylella Fastidiosa ◽  
Assessment Method ◽  
Ordinal Scale ◽  
Severity Assessment ◽  
Plant Host ◽  
Perfect Agreement ◽  
Accuracy And Precision ◽  
Percent Area ◽  
True Color

Nicotiana tabacum, a non-natural host, is an excellent plant model for biological and functional genomics studies on plant host-Xylella fastidiosa interactions. Symptoms by X. fastidiosa subsp. pauca on tobacco have been characterized but current severity assessment method is an ordinal scale developed for symptoms on citrus. We designed a standard area diagram (SAD) to aid in the visual estimation of percent area affected (% severity) and performed a multi-laboratory validation on tobacco cv. 'Havana inoculated with X. fastidiosa subsp. pauca. Inoculated plants were monitored over time and digital images of the symptoms were obtained. Three different softwares (APS Asses, ImageJ and Leaf Doctor) were used to segment the images and calculate % severity. Ten true-color images composed a 10-image SAD (0.5, 5, 10, 15, 25, 35, 45, 55, 65 and 75%). Fifty raters at four laboratories assigned % severity first without and then with the SAD on the same testing image set of 40 images following the same instructions provided by an examiner at each Laboratory. The means of % severity by all softwares were assumed to represent the actual % severity given the perfect agreement between them. The unaided estimates were less precise, biased towards overestimation (up to 50 percent points) and less concordant between raters. Accuracy and precision varied considerably among the raters and effect of the SAD on the overall concordance to the actual severity was dependent on the Laboratory; in all but one Laboratory, the group means of the agreement index statistically improved. The between-rater agreement improved in all Laboratories when using the SAD. The SAD may help to standardize and allow comparison across different laboratories, but care should be taken during instructions on how to discriminate symptoms that are not readily discernible as well as on how to correctly use of the SAD.

Severity assessment in the Nicotiana tabacum-Xylella fastidiosa subsp. pauca pathosystem: design and interlaboratory validation of a standard area diagram set

2020 ◽  
Vol 45 (6) ◽  
pp. 710-722
Author(s):  
Willian Eduardo Lino Pereira ◽  
Sheila Maria Pereira de Andrade ◽  
Emerson M. Del Ponte ◽  
Mariana Bossi Esteves ◽  
Maria Cristina Canale ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Xylella Fastidiosa ◽  
Severity Assessment ◽  
Interlaboratory Validation

scholarly journals Early Wound Healing Score (EHS): An Intra- and Inter-Examiner Reliability Study

2019 ◽  
Vol 7 (3) ◽  
pp. 86
Author(s):  
Lorenzo Marini ◽  
Philipp Sahrmann ◽  
Mariana Andrea Rojas ◽  
Camilla Cavalcanti ◽  
Giorgio Pompa ◽  
...  
Keyword(s):  
Wound Healing ◽  
Correlation Coefficient ◽  
Soft Tissues ◽  
Assessment Method ◽  
Perfect Agreement ◽  
Healing Score ◽  
Healing Assessment ◽  
Early Healing ◽  
Intra Class Correlation Coefficient ◽  
Early Wound

The early wound healing score (EHS) was introduced to assess early wound healing of periodontal soft tissues after surgical incision. The purpose of this study is to evaluate the intra- and inter-examiner reliability of the EHS. Six examiners with different levels of training and clinical focus were enrolled. Each examiner was trained on the use of the EHS before starting the study. Thereafter, 63 photographs of three different types of surgical incisions taken at day 1, 3 or 7 post-operatively were independently evaluated according to the proposed assessment method. A two-way random intra-class correlation coefficient (ICC) and 95% confidence interval (CI) were used to analyze the intra- and inter-examiner reliability for the EHS. The inter-examiner reliability for the EHS was 0.828 (95% CI: 0.767–0.881). The intra-examiner reliability ranged between 0.826 (95% CI: 0.728–0.891) and 0.915 (95% CI: 0.856–0.950). The results therefore show an “almost perfect agreement” for intra- and inter-examiner reliability. The EHS provides a system for reproducible repeated ratings for the early healing assessment of incisions of periodontal soft tissues. Even when used by examiners with different clinical experience and specialty, it shows a high correlation coefficient.

scholarly journals Calcium-Enhanced Twitching Motility in Xylella fastidiosa Is Linked to a Single PilY1 Homolog

2014 ◽  
Vol 80 (23) ◽  
pp. 7176-7185 ◽  
Author(s):  
Luisa F. Cruz ◽  
Jennifer K. Parker ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente
Keyword(s):  
Xylella Fastidiosa ◽  
Xylem Sap ◽  
Active Movement ◽  
Binding Motif ◽  
Twitching Motility ◽  
Structural Protein ◽  
Plant Host ◽  
Content Type ◽  
Type Iv ◽  
Functional Differences

ABSTRACTThe plant-pathogenic bacteriumXylella fastidiosais restricted to the xylem vessel environment, where mineral nutrients are transported through the plant host; therefore, changes in the concentrations of these elements likely impact the growth and virulence of this bacterium. Twitching motility, dependent on type IV pili (TFP), is required for movement against the transpiration stream that results in basipetal colonization. We previously demonstrated that calcium (Ca) increases the motility ofX. fastidiosa, although the mechanism was unknown. PilY1 is a TFP structural protein recently shown to bind Ca and to regulate twitching and adhesion in bacterial pathogens of humans. Sequence analysis identified threepilY1homologs inX. fastidiosa(PD0023, PD0502, and PD1611), one of which (PD1611) contains a Ca-binding motif. Separate deletions of PD0023 and PD1611 resulted in mutants that still showed twitching motility and were not impaired in attachment or biofilm formation. However, the response of increased twitching at higher Ca concentrations was lost in thepilY1-1611 mutant. Ca does not modulate the expression of any of theX. fastidiosaPilY1 homologs, although it increases the expression of the retraction ATPasepilTduring active movement. The evidence presented here suggests functional differences between the PilY1 homologs, which may provideX. fastidiosawith an adaptive advantage in environments with high Ca concentrations, such as xylem sap.

scholarly journals Validation of a diagrammatic scale for quantification of bacterial leaf blight (causal agent Pseudomonas avenae) in maize

2020 ◽  
Vol 41 (6) ◽  
pp. 2467-2480
Author(s):  
Eloisa Lorenzett ◽  
◽  
Juliano Tartaro ◽  
José Renato Stangarlin ◽  
Roberto Luis Portz ◽  
...  
Keyword(s):  
Visual Stimulus ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Economic Damage ◽  
Severity Assessment ◽  
Total Leaf Area ◽  
Accuracy And Precision ◽  
Injured Area ◽  
Different Levels ◽  
Diagrammatic Scale

Bacterial leaf blight occurs in almost the entire Brazilian territory and can cause significant economic damage. However, its effects can be curtailed with the following tools that aid in quantification for carrying out the best severity assessment that can be applied to the studies used in its control. The objective of this study was to develop and validate a diagrammatic scale to quantify the severity of bacterial leaf blight in maize caused by Pseudomonas avenae. Corn leaves were collected with different levels of disease severity, and the total leaf area as well as the injured area of the middle third of each leaf was measured. From this, the minimum and maximum limits of the disease and, subsequently, four intermediate levels were determined whilst taking into account the law of visual stimulus of Weber-Fechner. Levels 1.5%, 2.5%, 9%, 18%, 46%, and 70% were selected with validation performed by eight evaluators, four inexperienced and four experienced. These evaluators estimated the severity values, initially without the use of the proposed diagrammatic scale and in a second attempt with the use of the scale. We concluded that it was possible to improve the accuracy and precision of the evaluators when they used the scale as a tool to assess the severity of bacterial leaf blight on corn leaves.

Overexpression of Citrus reticulata SAMT in Nicotiana tabacum increases MeSA volatilization and decreases Xylella fastidiosa symptoms

Planta ◽  
2020 ◽  
Vol 252 (6) ◽  
Author(s):  
Laura M. Gómez ◽  
Natália S. Teixeira-Silva ◽  
Raquel Caserta ◽  
Marco A. Takita ◽  
Márcia O. M. Marques ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Xylella Fastidiosa ◽  
Citrus Reticulata

scholarly journals In the Eye of the Beholder: The Effect of Rater Variability and Different Rating Scales on QTL Mapping

2011 ◽  
Vol 101 (2) ◽  
pp. 290-298 ◽  
Author(s):  
Jesse A. Poland ◽  
Rebecca J. Nelson
Keyword(s):  
Disease Resistance ◽  
Qtl Mapping ◽  
Disease Severity ◽  
Rating Scales ◽  
Ordinal Scale ◽  
Disease Assessment ◽  
True Value ◽  
Accuracy And Precision ◽  
Rater Variability ◽  
The Impact

The agronomic importance of developing durably resistant cultivars has led to substantial research in the field of quantitative disease resistance (QDR) and, in particular, mapping quantitative trait loci (QTL) for disease resistance. The assessment of QDR is typically conducted by visual estimation of disease severity, which raises concern over the accuracy and precision of visual estimates. Although previous studies have examined the factors affecting the accuracy and precision of visual disease assessment in relation to the true value of disease severity, the impact of this variability on the identification of disease resistance QTL has not been assessed. In this study, the effects of rater variability and rating scales on mapping QTL for northern leaf blight resistance in maize were evaluated in a recombinant inbred line population grown under field conditions. The population of 191 lines was evaluated by 22 different raters using a direct percentage estimate, a 0-to-9 ordinal rating scale, or both. It was found that more experienced raters had higher precision and that using a direct percentage estimation of diseased leaf area produced higher precision than using an ordinal scale. QTL mapping was then conducted using the disease estimates from each rater using stepwise general linear model selection (GLM) and inclusive composite interval mapping (ICIM). For GLM, the same QTL were largely found across raters, though some QTL were only identified by a subset of raters. The magnitudes of estimated allele effects at identified QTL varied drastically, sometimes by as much as threefold. ICIM produced highly consistent results across raters and for the different rating scales in identifying the location of QTL. We conclude that, despite variability between raters, the identification of QTL was largely consistent among raters, particularly when using ICIM. However, care should be taken in estimating QTL allele effects, because this was highly variable and rater dependent.

scholarly journals Nursing Students’ Perception and Attitude toward Objective Structured Clinical Examination (OSCE) in Oman

2021 ◽  
Author(s):  
Shaikha Alamri ◽  
Iman Al Hashmi ◽  
Kholah Shruba ◽  
Suad Jamaan ◽  
Zaina Alrahbi ◽  
...  
Keyword(s):  
Nursing Education ◽  
Nursing Students ◽  
Clinical Examination ◽  
Assessment Method ◽  
Objective Structured Clinical Examination ◽  
Ordinal Scale ◽  
Cross Sectional ◽  
Undergraduate Nursing Students ◽  
Undergraduate Nursing ◽  
Strongly Agree

Objective: To explore undergraduate nursing students’ perception and attitude toward the OSCE. Methods: This cross-sectional descriptive study was conducted between April-May 2020, among undergraduate nursing students in the College of Nursing at Sultan Qaboos University. Two self-administered questionnaires were employed to obtain data on students’ perception and attitude toward OSCE. Students’ feedback on OSCE was collected using open-ended questions about OSCE strengths, weakness, and recommendation for improvement. Surveys responses were based on a 5-point ordinal scale ranging from strongly disagree to strongly agree. Students’ Feedback on OSCE was analyzed as descriptive data by identifying the common themes and categorize them in groups. Results: A total of 160 students completed the study questionnaires. Most agreed that OSCE atmosphere is not good (66.3%) and it shouldn’t be the only mode of practical Examination (40.6%). Also, 64.4% of the students felt that timing allocated to complete the skills was not adequate. The data shows that 33.1% of the examinees felt that OSCE examination is more stressful than clinical examination. In addition, few students supported that OSCE has improved their communication skills and it increased their confidence level to perform nursing skills. Conclusion: The findings of this study appear alarming in regard to students’ perception about the overall process and the validity of OSCE examination as an assessment method. Nursing educators need to consider further evaluation and improvement of the OSCE in order to improve students’ acceptance and appreciation of OSCE as an important form of clinical learning and as an assessment method. Keywords: Objective Structured Clinical Examination; Nursing Education; Baccalaureate; Evaluation; Attitude; Nursing Students; Practical Nursing.

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