Body Composition Characteristics of a Load-Capacity Model: Age-Dependent and Sex-Specific Percentiles in 5- To 17-Year-Old Children

Introduction: Body composition assessment is superior to the use of body mass index (BMI) to characterize the nutritional status in pediatric populations. For data interpretation, suitable reference data are needed; hence, we aimed to generate age-dependent and sex-specific body composition reference data in a larger population of children and adolescents in Germany. Methods: This is a cross-sectional study on a representative group of 15,392 5- to 17-year-old children and adolescents. Body composition was assessed by bioelectrical impedance analysis using a population-specific algorithm validated against air displacement plethysmography. Age- and sex-specific percentiles for BMI, fat mass index (FMI), fat-free mass index (FFMI), and a “load-capacity model” (characterized by the ratios of fat mass [FM]/ fatt-free mass [FFM] and FM/FFM2) were modeled using the LMS method. Results: BMI, FMI, FFMI, FM/FFM, and FM/FFM2 curves showed similar shapes between boys and girls with steady increases in BMI, FMI, and FFMI, while FM/FFM2-centiles decreased during early childhood and adolescence. Sex differences were observed in FMI and FM/FFM percentiles with increases in FMI up to age 9 years followed by a steady decrease in FM/FFM during and after puberty with a fast-growing FFMI up to age 17 in boys. The prevalence of low FFM relative to FM reached more than 60% in overweight children and adolescents. Conclusion: These pediatric body composition reference data enable physicians and public health scientists to monitor body composition during growth and development and to interpret individual data. The data point out to an early risk of sarcopenia in overweight children and adolescents

Citrus huanglongbing associated with ‘Candidatus liberibacter asiaticus’ present in the northern region of Costa Rica but has not been detected in other citrus-growing areas

Since 2011, citrus Huanglongbing (HLB, ex-greening) disease has been detected in Los Chiles, Costa Rica, close to the Nicaraguan border, by the State Phytosanitary Service (Servicio Fitosanitario del Estado; SFE) and by TicoFrut’s Agricultural Diagnostic Laboratory (Arredondo-Bernal et al. 1999; SFE 2011). However, there has not been a formal scientific report confirming its presence by two independent methods, nor has there been an update on the spread of the disease to other parts of the country. Sweet orange (Citrus sinensis) trees in Los Chiles showing zinc deficiency, vein yellowing, blotchy mottle, and corky veins resembling HLB disease were sampled. Genomic DNA was extracted from leaf midrib and petiole, and Asian citrus psyllid (Diphorina citri) samples using DNeasy Plant, and Blood and Tissue extraction kits (Qiagen, Hilden, Germany). Quantitative polymerase chain reaction (qPCR; TaqMan probes) assays (Li et al. 2006) detected the presence of ‘Candidatus Liberibacter asiaticus’ in 30 symptomatic tree samples. The intergenic region between rplA and rplJ of the β-operon (Hocquellet et al. 1999) was amplified from eight plant and two psyllid samples containing five insects each, and was directly sequenced (Macrogen, Korea) to corroborate the presence of ‘Ca. L. asiaticus’. All sequences obtained from plants and D. citri shared 100% identity with each other, and a BLAST search showed a 99% identity to different sequences of ‘Ca. L. asiaticus’ available in GenBank, e.g., some from India (KC477384). Although D. citri is present in the country (Villalobos et al. 2005), the disease has not been detected in other growing areas. Three hundred seventeen trees and 32 psyllid samples were tested as described above for the presence of ‘Ca. L. asiaticus’ by qPCR in July through September 2013, and April through May 2014. Sampled trees were grown in the San Jose, Alajuela, and Puntarenas provinces, and showed chlorosis-like zinc deficiency. None of the samples tested positive for ‘Ca. L. asiaticus’. Ct values were above 36 or undetected, while internal control (COX) values ranged from 17 to 23. Considering that Costa Rica is a small country, the containment or the failure to detect ‘Ca. L. asiaticus’ in other regions was unexpected. This phenomenon can be due to the SFE’s and the private sector’s quarantine and containment plans (Arredondo-Bernal et al. 2013); however, there may be other factors that are containing the disease that have not been studied. © 2015 The American Phytopathological Society

Citrus Huanglongbing Associated with ‘Candidatus Liberibacter asiaticus’ Present in the Northern Region of Costa Rica but Has Not Been Detected in Other Citrus- Growing Areas

Since 2011, citrus Huanglongbing (HLB, ex-greening) disease has been detected in Los Chiles, Costa Rica, close to the Nicaraguan border, by the State Phytosanitary Service (Servicio Fitosanitario del Estado; SFE) and by TicoFrut’s Agricultural Diagnostic Laboratory (Arredondo-Bernal et al. 1999; SFE 2011). However, there has not been a formal scientific report confirming its presence by two independent methods, nor has there been an update on the spread of the disease to other parts of the country. Sweet orange (Citrus sinensis) trees in Los Chiles showing zinc deficiency, vein yellowing, blotchy mottle, and corky veins resembling HLB disease were sampled. Genomic DNA was extracted from leaf midrib and petiole, and Asian citrus psyllid (Diphorina citri) samples using DNeasy Plant, and Blood and Tissue extraction kits (Qiagen, Hilden, Germany). Quantitative polymerase chain reaction (qPCR; TaqMan probes) assays (Li et al. 2006) detected the presence of ‘Candidatus Liberibacter asiaticus’ in 30 symptomatic tree samples. The intergenic region between rplA and rplJ of the β-operon (Hocquellet et al. 1999) was amplified from eight plant and two psyllid samples containing five insects each, and was directly sequenced (Macrogen, Korea) to corroborate the presence of ‘Ca. L. asiaticus’. All sequences obtained from plants and D. citri shared 100% identity with each other, and a BLAST search showed a 99% identity to different sequences of ‘Ca. L. asiaticus’ available in GenBank, e.g., some from India (KC477384). Although D. citri is present in the country (Villalobos et al. 2005), the disease has not been detected in other growing areas. Three hundred seventeen trees and 32 psyllid samples were tested as described above for the presence of ‘Ca. L. asiaticus’ by qPCR in July through September 2013, and April through May 2014. Sampled trees were grown in the San Jose, Alajuela, and Puntarenas provinces, and showed chlorosis-like zinc deficiency. None of the samples tested positive for ‘Ca. L. asiaticus’. Ct values were above 36 or undetected, while internal control (COX) values ranged from 17 to 23. Considering that Costa Rica is a small country, the containment or the failure to detect ‘Ca. L. asiaticus’ in other regions was unexpected. This phenomenon can be due to the SFE’s and the private sector’s quarantine and containment plans (Arredondo-Bernal et al. 2013); however, there may be other factors that are containing the disease that have not been studied.Universidad de Costa Rica/[801-B2-653]/UCR/Costa RicaUniversidad de Costa Rica/[801-A1-801]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Agronomí

pH-Dependent Structures of the Manganese Binding Sites in Oxalate Decarboxylase as Revealed by High-Field Electron Paramagnetic Resonance

A high-field electron paramagnetic resonance (HFEPR) study of oxalate decarboxylase (OxdC) is reported. OxdC breaks down oxalate to carbon dioxide and formate and possesses two distinct manganese(II) binding sites, referred to as site−1 and −2. The Mn(II) zero-field interaction was used to probe the electronic state of the metal ion and to examine chemical/mechanistic roles of each of the Mn(II) centers. High magnetic-fields were exploited not only to resolve the two sites, but also to measure accurately the Mn(II) zero-field parameters of each of the sites. The spectra exhibited surprisingly complex behavior as a function of pH. Six different species were identified based on their zero-field interactions, two corresponding to site-1 and four states to site-2. The assignments were verified using a mutant that only affected site-1. The speciation data determined from the HFEPR spectra for site −2 was consistent with a simple triprotic equilibrium model, while the pH dependence of site-1 could be described by a single pKa. This pH dependence was independent of the presence of the His-tag and of whether the preparations contained 1.2 or 1.6 Mn per subunit. Possible structures of the six species are proposed based on spectroscopic data from model complexes and existing protein crystallographic structures obtained at pH 8 are discussed. Although site-1 has been identified as the active site and no role has been assigned to site-2, the pronounced changes in the electronic structure of the latter and its pH behavior, which also matches the pH-dependent activity of this enzyme, suggests that even if the conversion of oxalate to formate is carried out at site-1, site-2 likely plays a catalytically relevant role