With increasing problems of decreased efficacy, toxicity and environmental degradation due to the use of chemical fungicides, there is urgent need for developing alternative strategies for managing crop diseases. One approach currently being explored is the application of safe organic-based compounds to prime the defence systems of plants in order to prevent or limit infections by pathogens. Chitosan, a deacylated derivative of chitin, is one of the compounds known to promote plant defence and growth, but the mechanisms by which it is able to do so are still unclear. This study investigated the ability of a commercial chitosan extract (Armour-Zen ® ) to reduce disease incidence and induce the production of enzymes and expression of marker genes involved in plant defences for two important tomato pathogens, Alternaria solani and Xanthomonas vesicatoria. Foliar spray applications of the chitosan extract significantly reduced the incidences of both diseases in greenhouse and field grown tomato plants and also displayed a positive effect on growth and yields of tomato fruits. Chitosan-treated plants recorded elevated levels of defence enzymes and upregulation of the PIN II marker gene for defence signalling pathways when compared to the control. It was therefore proposed that chitosan would able to provide broad-range protection through induced systemic resistance mechanisms.
In this study, we report the first isolation of three antibiotic indole alkaloid compounds from a Pseudomonad bacterium, Pseudomonas aeruginosa UWI-1. The bacterium was batch fermented in a modified Luria Broth medium and compounds were solvent extracted and isolated by bioassay-guided fractionation. The three compounds were identified as (1) tris(1H-indol-3-yl) methylium, (2) bis(indol-3-yl) phenylmethane, and (3) indolo (2, 1b) quinazoline-6, 12 dione. A combination of 1D and 2D NMR, high-resolution mass spectrometry data and comparison from related data from the literature was used to determine the chemical structures of the compounds. Compounds 1–3 were evaluated in vitro for their antimicrobial activities against a wide range of microorganisms using the broth microdilution technique. Compounds 1 and 2 displayed antibacterial activity against only Gram-positive pathogens, although 1 had significantly lower minimum inhibitory concentration (MIC) values than 2. Compound 3 displayed potent broad-spectrum antimicrobial activity against a range of Gram positive and negative bacteria. Several genes identified from the genome of P. aeruginosa UWI-1 were postulated to contribute to the biosynthesis of these compounds and we attempted to outline a possible route for bacterial synthesis. This study demonstrated the extended metabolic capability of Pseudomonas aeruginosa in synthesizing new chemotypes of bioactive compounds.
Background and aims: Assessment of mucosal visualization during esophagogastroduodenoscopy (EGD) can be improved with a standardized scoring system. To address this gap, we created the Toronto Upper Gastrointestinal Cleaning Score (TUGCS).
Methods: We developed the TUGCS using Delphi methodology, whereby an international group of endoscopy experts iteratively rated their agreement with proposed TUGCS items and anchors on a 5-point Likert scale. After each Delphi round, we analyzed responses and refined the TUGCS using an 80% agreement threshold for consensus. We used the intra-class correlation coefficient (ICC) to assess inter-rater and test-retest reliability. We assessed internal consistency with Cronbach’s alpha and item-total and inter-item correlations with Pearson’s Correlation Coefficient. We compared TUGCS ratings with an independent endoscopist’s global rating of mucosal visualization using Spearman’s rho.
Results: We achieved consensus with 14 Delphi participants after three Delphi rounds. Inter-rater reliability was high at 0.79 (95% CI [0.64-0.88]). Test-retest reliability was excellent at 0.83 (95% CI [0.77-0.87]). Cronbach’s α was 0.81, item-total correlations ranged from 0.52-0.69, and inter-item correlations ranged from 0.38-0.74. There was a positive correlation between TUGCS ratings and a global rating of visualization (r = 0.41, p=0.002). TUGCS ratings for EGDs with global ratings of excellent were significantly higher than EGDs with global ratings of fair (p=0.010).
Conclusion: The TUGCS has strong evidence of validity in the clinical setting. The international group of assessors, broad variety of EGD indications, and minimal assessor training improves generalizability and potential for dissemination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.