Laccases and Peroxidases Co-Localize in Lignified Secondary Cell Walls throughout Stem Development.

Lignin, a critical phenolic polymer in secondary cell walls of plant cells, enables strength in fibers and water transportation in xylem vessel elements. Secreted enzymes, namely laccases (LACs) and peroxidases (PRXs), facilitate lignin polymerization by oxidizing lignin monomers (monolignols). Previous work in Arabidopsis (Arabidopsis thaliana) demonstrated that AtLAC4 and AtPRX64 localized to discrete lignified cell wall domains in fibers, although the spatial distributions of other enzymes in these large gene families are unknown. Here, we show that characteristic sets of putative lignin-associated LACs and PRXs localize to precise regions during stem development, with LACs and PRXs co-occurring in cell wall domains. AtLAC4, AtLAC17, and AtPRX72 localized to the thick secondary cell wall of xylem vessel elements and fibers, whereas AtLAC4, AtPRX64, and AtPRX71 localized to fiber cell corners. Interestingly, AtLAC4 had a transient cell corner localization early in fiber development that disappeared in the mature stem. In contrast with these secondary cell wall localizations, AtLAC10, AtPRX42, AtPRX52, and AtPRX71 were found in nonlignified tissues. Despite ubiquitous PRX occurrence in cell walls, PRX oxidative activity was restricted to lignifying regions during development, which suggested regulated production of apoplastic hydrogen peroxide. Relative amounts of apoplastic reactive oxygen species differed between lignified cell types, which could modulate PRX activity. Together, these results indicate that precise localization of oxidative enzymes and differential distribution of oxidative substrates, such as hydrogen peroxide, provide mechanisms to control spatiotemporal deposition of lignin during development.

Physical Activity, BMI, and Blood Pressure in US Youth: NHANES 2003-2006.

PURPOSE: The objective of this study was to examine the independent and combined association of physical activity and body mass index (BMI) with blood pressure in youth. METHODS: Youth aged 8-18 years from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) with BMI, blood pressure, and physical activity (accelerometer) were included in the analyses. A total of 2585 subjects (1303 males; 47% of all 8- to 18-year-olds) met these criteria. RESULTS: Obese youth had a systolic blood pressure that was 8 mm Hg higher than normal weight youth. A significant interaction between BMI and physical activity on blood pressure was found (P < .001), and group differences among the BMI/activity groups showed that the 3 obese groups and the overweight/least active group had significantly higher systolic blood pressure than the normal weight/active group across all analyses. The overweight/least active and normal weight/least active groups had significantly higher diastolic blood pressure than the normal weight/active group as well. CONCLUSIONS: This study showed a significant independent and combined association of BMI and physical activity with blood pressure in youth. Interventions need to focus on the reduction of fatness/BMI as a way to reduce the cardiovascular risk in youth.

Project FIT: A School, Community and Social Marketing Intervention Improves Healthy Eating Among Low-Income Elementary School Children.

Project FIT was a two-year multi-component nutrition and physical activity intervention delivered in ethnically-diverse low-income elementary schools in Grand Rapids, MI. This paper reports effects on children's nutrition outcomes and process evaluation of the school component. A quasi-experimental design was utilized. 3rd, 4th and 5th-grade students (Yr 1 baseline: N = 410; Yr 2 baseline: N = 405; age range: 7.5-12.6 years) were measured in the fall and spring over the two-year intervention. Ordinal logistic, mixed effect models and generalized estimating equations were fitted, and the robust standard errors were utilized. Primary outcomes favoring the intervention students were found regarding consumption of fruits, vegetables and whole grain bread during year 2. Process evaluation revealed that implementation of most intervention components increased during year 2. Project FIT resulted in small but beneficial effects on consumption of fruits, vegetables, and whole grain bread in ethnically diverse low-income elementary school children.

Knowledge of physical activity and nutrition recommendations in college students.

Objective Assess physical activity (PA) and nutrition recommendation knowledge in college students. Participants: 71 students (n = 41 females;18 to 22 years) measured in May of 2014. METHODS: Knowledge of existence and accuracy of PA and nutrition recommendations were assessed via a verbal survey. Results: Most (67.6%) were aware PA recommendations exist, but only 26.8% could accurately report them. Almost all (91.5%) were aware nutrition guidelines exist, but no higher than 23.9% answered any specific recommendation correctly. There were no significant associations between sex or body mass index (BMI) and either awareness or accuracy of PA or nutrition recommendations. Non-Kinesiology majors were 3.3 times more likely to answer that they were not aware of the existence of PA recommendations, compared to Kinesiology majors. Conclusions: Accurate knowledge of the PA and nutrition recommendations are very low and given that the majority of participants were categorized as overweight or obese, teaching these guidelines needs to be the priority.

Reproducibility of the Veterans Physical Activity Questionnaire in an elderly population.

BACKGROUND: Quantifying lifetime physical activity using self-reported measures is challenging due to reliance on recall, especially in older populations. The purpose of this study was to determine the 1-year reproducibility of the Veterans Physical Activity Questionnaire (VAPAQ) in a cohort of patients with documented abdominal aortic aneurysm disease (AAA). METHODS: Subjects included men (n = 52) and women (n = 3) enrolled in AAA STOP, a randomized trial designed to test the ability of supervised exercise training to modify AAA biology and early disease progression. RESULTS: The overall correlation coefficient for lifetime recreational energy expenditure between the 2 examinations was 0.93 (P < .001), with an overall difference of 26 kcal/week, a typical error (standard deviation of the differences) of 171 kcals/week, and a coefficient of variation (CV) of 15.5%. CONCLUSIONS: The VAPAQ is a reproducible tool to quantify lifetime energy expenditure in older adults with documented vascular disease.

Junk food consumption and screen time: association with childhood adiposity.

OBJECTIVES: To determine the joint association of junk food consumption (JFC) and screen time (ST) with adiposity in children. METHODS: Two hundred fourteen (121 girls, 93 boys) third-to-fifth-grade students (54% Hispanic, 35% African American, 8% white) completed a lifestyle behavior survey, which included self-reported JFC and ST, as part of a school-based lifestyle intervention program. RESULTS: Neither JFC nor ST, independently or jointly, was associated with adiposity measures. JFC and ST were significantly correlated (r = .375). CONCLUSIONS: The low achievement of physical activity and screen time recommendations and high prevalence of overweight/obesity in this mostly minority, low socioeconomic status population indicates a potential focus for intervention.