Metabolomic Patterns of Septoria Canker Resistant and Susceptible Populus trichocarpa Genotypes 24 Hours Postinoculation.

Sphaerulina musiva is an economically and ecologically important fungal pathogen that causes Septoria stem canker and leaf spot disease of Populus species. To bridge the gap between genetic markers and structural barriers previously found to be linked to Septoria canker disease resistance in poplar, we used hydrophilic interaction liquid chromatography and tandem mass spectrometry to identify and quantify metabolites involved with signaling and cell wall remodeling. Fluctuations in signaling molecules, organic acids, amino acids, sterols, phenolics, and saccharides in resistant and susceptible P. trichocarpa inoculated with S. musiva were observed. The patterns of 222 metabolites in the resistant host implicate systemic acquired resistance (SAR), cell wall apposition, and lignin deposition as modes of resistance to this hemibiotrophic pathogen. This pattern is consistent with the expected response to the biotrophic phase of S. musiva colonization during the first 24 h postinoculation. The fungal pathogen metabolized key regulatory signals of SAR, other phenolics, and precursors of lignin biosynthesis that were depleted in the susceptible host. This is the first study to characterize metabolites associated with the response to initial colonization by S. musiva between resistant and susceptible hosts.

Mapping X-Disease Phytoplasma Resistance in Prunus virginiana.

Phytoplasmas such as "Candidatus Phytoplasma pruni," the causal agent of X-disease of stone fruits, lack detailed biological analysis. This has limited the understanding of plant resistance mechanisms. Chokecherry (Prunus virginiana L.) is a promising model to be used for the plant-phytoplasma interaction due to its documented ability to resist X-disease infection. A consensus chokecherry genetic map "Cho" was developed with JoinMap 4.0 by joining two parental maps. The new map contains a complete set of 16 linkage groups, spanning a genetic distance of 2,172 cM with an average marker density of 3.97 cM. Three significant quantitative trait loci (QTL) associated with X-disease resistance were identified contributing to a total of 45.9% of the phenotypic variation. This updated genetic linkage map and the identified QTL will provide the framework needed to facilitate molecular genetics, genomics, breeding, and biotechnology research concerning X-disease in chokecherry and other Prunus species.

Cognitive load imposed by ultrasound-facilitated teaching does not adversely affect gross anatomy learning outcomes.

Ultrasonography is increasingly used in medical education, but its impact on learning outcomes is unclear. Adding ultrasound may facilitate learning, but may also potentially overwhelm novice learners. Based upon the framework of cognitive load theory, this study seeks to evaluate the relationship between cognitive load associated with using ultrasound and learning outcomes. The use of ultrasound was hypothesized to facilitate learning in anatomy for 161 novice first-year medical students. Using linear regression analyses, the relationship between reported cognitive load on using ultrasound and learning outcomes as measured by anatomy laboratory examination scores four weeks after ultrasound-guided anatomy training was evaluated in consenting students. Second anatomy examination scores of students who were taught anatomy with ultrasound were compared with historical controls (those not taught with ultrasound). Ultrasound's perceived utility for learning was measured on a five-point scale. Cognitive load on using ultrasound was measured on a nine-point scale. Primary outcome was the laboratory examination score (60 questions). Learners found ultrasound useful for learning. Weighted factor score on "image interpretation" was negatively, but insignificantly, associated with examination scores [F (1,135) = 0.28, beta = -0.22; P = 0.61]. Weighted factor score on "basic knobology" was positively and insignificantly associated with scores; [F (1,138) = 0.27, beta = 0.42; P = 0.60]. Cohorts exposed to ultrasound had significantly higher scores than historical controls (82.4% ± SD 8.6% vs. 78.8% ± 8.5%, Cohen's d = 0.41, P < 0.001). Using ultrasound to teach anatomy does not negatively impact learning and may improve learning outcomes. Anat Sci Educ 10: 144-151. © 2016 American Association of Anatomists.

The distinct category of healthcare associated bloodstream infections.

BACKGROUND: Bloodstream infections (BSI) have been traditionally classified as either community acquired (CA) or hospital acquired (HA) in origin. However, a third category of healthcare-associated (HCA) community onset disease has been increasingly recognized. The objective of this study was to compare and contrast characteristics of HCA-BSI with CA-BSI and HA-BSI. METHODS: All first episodes of BSI occurring among adults admitted to hospitals in a large health region in Canada during 2000-2007 were identified from regional databases. Cases were classified using a series of validated algorithms into one of HA-BSI, HCA-BSI, or CA-BSI and compared on a number of epidemiologic, microbiologic, and outcome characteristics. RESULTS: A total of 7,712 patients were included; 2,132 (28%) had HA-BSI, 2,492 (32%) HCA-BSI, and 3,088 (40%) had CA-BSI. Patients with CA-BSI were significantly younger and less likely to have co-morbid medical illnesses than patients with HCA-BSI or HA-BSI (p < 0.001). The proportion of cases in males was higher for HA-BSI (60%; p < 0.001 vs. others) as compared to HCA-BSI or CA-BSI (52% and 54%; p = 0.13). The proportion of cases that had a poly-microbial etiology was significantly lower for CA-BSI (5.5%; p < 0.001) compared to both HA and HCA (8.6 vs. 8.3%). The median length of stay following BSI diagnosis 15 days for HA, 9 days for HCA, and 8 days for CA (p < 0.001). Overall the most common species causing bloodstream infection were Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. The distribution and relative rank of importance of these species varied according to classification of acquisition. Twenty eight day all cause case-fatality rates were 26%, 19%, and 10% for HA-BSI, HCA-BSI, and CA-BSI, respectively (p < 0.001). CONCLUSION: Healthcare-associated community onset infections are distinctly different from CA and HA infections based on a number of epidemiologic, microbiologic, and outcome characteristics. This study adds further support for the classification of community onset BSI into separate CA and HCA categories.