Glyphosate resistance in Ambrosia trifida: Part 1. Novel rapid cell death response to glyphosate.

BACKGROUND: Glyphosate-resistant (GR) Ambrosia trifida is now present in the midwestern United States and in southwestern Ontario, Canada. Two distinct GR phenotypes are known, including a rapid response (GR RR) phenotype, which exhibits cell death within hours after treatment, and a non-rapid response (GR NRR) phenotype. The mechanisms of resistance in both GR RR and GR NRR remain unknown. Here, we present a description of the RR phenotype and an investigation of target-site mechanisms on multiple A. trifida accessions. RESULTS: Glyphosate resistance was confirmed in several accessions, and whole-plant levels of resistance ranged from 2.3- to 7.5-fold compared with glyphosate-susceptible (GS) accessions. The two GR phenotypes displayed similar levels of resistance, despite having dramatically different phenotypic responses to glyphosate. Glyphosate resistance was not associated with mutations in EPSPS sequence, increased EPSPS copy number, EPSPS quantity, or EPSPS activity. CONCLUSION: These encompassing results suggest that resistance to glyphosate in these GR RR A. trifida accessions is not conferred by a target-site resistance mechanism. © 2017 Society of Chemical Industry.

Glyphosate resistance in Ambrosia trifida: Part 2. Rapid response physiology and non-target-site resistance.

BACKGROUND: The glyphosate-resistant rapid response (GR RR) resistance mechanism in Ambrosia trifida is not due to target-site resistance (TSR) mechanisms. This study explores the physiology of the rapid response and the possibility of reduced translocation and vacuolar sequestration as non-target-site resistance (NTSR) mechanisms. RESULTS: GR RR leaf discs accumulated hydrogen peroxide within minutes of glyphosate exposure, but only in mature leaf tissue. The rapid response required energy either as light or exogenous sucrose. The combination of phenylalanine and tyrosine inhibited the rapid response in a dose-dependent manner. Reduced glyphosate translocation was observed in GR RR, but only when associated with tissue death caused by the rapid response. Nuclear magnetic resonance studies indicated that glyphosate enters the cytoplasm and reaches chloroplasts, and it is not moved into the vacuole of GR RR, GR non-rapid response or glyphosate-susceptible A. trifida. CONCLUSION: The GR RR mechanism of resistance is not associated with vacuole sequestration of glyphosate, and the observed reduced translocation is likely a consequence of rapid tissue death. Rapid cell death was inhibited by exogenous application of aromatic amino acids phenylalanine and tyrosine. The mechanism by which these amino acids inhibit rapid cell death in the GR RR phenotype remains unknown, and it could involve glyphosate phytotoxicity or other agents generating reactive oxygen species. Implications of these findings are discussed. The GR RR mechanism is distinct from the currently described glyphosate TSR or NTSR mechanisms in other species. © 2017 Society of Chemical Industry.

Multiple health behavior change in adults with or at risk for cancer: a systematic review.

OBJECTIVES: To identify components of efficacious interventions for multiple health behavior change (MHBC) in adult cancer survivors or adults at high risk for cancer. METHODS: A systematic review of MHBC interventions was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. RESULTS: Ten studies met inclusion criteria. Most studies changed at least 2 health behaviors. Diet, exercise, and smoking cessation were consistently changed with in-person interventions. Longer duration interventions using phone or mail contact had a positive association with changing diet and exercise. CONCLUSIONS: MHBC interventions positively influenced behavior change in adults with cancer and those at high risk for cancer. Future studies should focus on increasing dissemination and implementation of efficacious interventions.

The delay between symptom onset and seeking professional treatment for anxiety and depressive disorders in a rural Australian sample.

BACKGROUND: Epidemiological research has revealed that the utilisation of professional mental health services is low among rural Australians, despite a similar prevalence of mental illness to urban communities. However, the extent of this unmet need and the length of delay to first seek treatment in rural communities remain unclear. The aim of this study was to investigate the delay among rural Australians in seeking treatment for anxiety and depressive disorders. METHOD: A total of 124 participants with an anxiety or depressive disorder according to the Composite International Diagnostic Interview (CIDI) who were participants of the Australian Rural Mental Health Study (ARMHS) were included in this study. Multivariate methods examined the contribution of clinical (onset age, disorder type and comorbidity), attitudinal/demographic (perceived stigma and current age) and structural (rurality) variables to the delay to first seek help. RESULTS: The average length of the delay was 18.7 years across disorders (range 0-67). The shortest delays were in depressive disorders (10.41 years) and the longest for social phobia (28.02 years). Multivariate analysis indicated that younger onset age, older current age, diagnosis of panic disorder or depressive disorder, and living in a remote (R) or very remote area (VR) were associated with delays of more than one year. CONCLUSION: Delays to first seek treatment for anxiety and depressive disorders appear to be far more prolonged in rural compared to urban Australia. This is particularly the case for Australian residents living in R and VR areas. This is of particular concern due to the significant mental health needs of rural Australians.

Stem cell infusion into the vein of Marshall.

The vein of Marshall (VOM) and related cardiac ganglia have been clearly implicated in atrial fibrillation. Electrophysiological procedures have targeted these sites of autonomic innervation. However, targeting the exact sites has proven technically challenging. Identifying the VOM and infusing stem cells may ablate related ganglia autonomic function and offer an innovative treatment for atrial fibrillation.