Resting Energy Expenditure Prediction in Recreational Athletes of 18–35 Years: Confirmation of Cunningham Equation and an Improved Weight-Based Alternative

Introduction

Resting energy expenditure (REE) is expected to be higher in athletes because of their relatively high fat free mass (FFM). Therefore, REE predictive equation for recreational athletes may be required. The aim of this study was to validate existing REE predictive equations and to develop a new recreational athlete specific equation.

Methods

90 (53M, 37F) adult athletes, exercising on average 9.1±5.0 hours a week and 5.0±1.8 times a week, were included. REE was measured using indirect calorimetry (Vmax Encore n29), FFM and FM were measured using air displacement plethysmography. Multiple linear regression analysis was used to develop a new FFM-based and weight-based REE predictive equation. The percentage accurate predictions (within 10% of measured REE), percentage bias, root mean square error and limits of agreement were calculated.

Results

The Cunningham equation and the new weight-based equation and the new FFM-based equation performed equally well. De Lorenzo''s equation predicted REE less accurate, but better than the other generally used REE predictive equations. Harris-Benedict, WHO, Schofield, Mifflin and Owen all showed less than 50% accuracy.

Conclusion

For a population of (Dutch) recreational athletes, the REE can accurately be predicted with the existing Cunningham equation. Since body composition measurement is not always possible, and other generally used equations fail, the new weight-based equation is advised for use in sports nutrition.     

The origin and evolution of <Emphasis Type="Italic">ARGFX</Emphasis>homeobox loci in mammalian radiation

Background  

Many homeobox genes show remarkable conservation between divergent animal phyla. In contrast, the ARGFX (Arginine-fifty homeobox) homeobox locus was identified in the human genome but is not present in mouse or invertebrates. Here we ask when and how this locus originated and examine its pattern of molecular evolution.     

Genetic mapping of the labile (lab) gene: a recessive locus causing irregular spikelet fertility in labile-barley (Hordeum vulgare convar. labile)

Key message

The recessive labile locus mapped on chromosome 5HL causes irregular spikelet fertility and controls floret development as well as row-type in barley.

Abstract

The labile-barley displays a variable number of fertile spikelets at each rachis internode (0–3 fertile spikelets/rachis internode) which is intermediate between that observed in two- or six-rowed types. Previous re-sequencing of Vrs1 in 219 labile-barley (Hordeum vulgare L. convar. labile) accessions showed that all carried a six-rowed specific allele. We therefore hypothesized that this seemingly random reduction in spikelet fertility is most likely caused by the labile (lab) locus, which we aimed to phenotypically and genetically define. Here, we report a detailed phenotypic analysis of spikelet fertility in labile-barleys in comparison to two- and six-rowed genotypes using scanning electron microscopy analysis. We found that the first visible morphological deviation occurred during the stamen primordium stage, when we regularly observed the appearance of arrested central floral primordia in labile but not in two- or six-rowed barleys. At late stamen and early awn primordium stages, lateral florets in two-rowed and only some in labile-barley showed retarded development and reduction in size compared with fully fertile lateral florets in six-rowed barley. We used two F₂ mapping populations to generate whole genome genetic linkage maps and ultimately locate the lab locus as a recessive Mendelian trait to a 4.5–5.8 cM interval at approximately 80 cM on chromosome 5HL. Our results will help identifying the role of the lab gene in relation to other spikelet fertility factors in barley.     

Cell Surface Profiling Using High-Throughput Flow Cytometry: A Platform for Biomarker Discovery and Analysis of Cellular Heterogeneity

Cell surface proteins have a wide range of biological functions, and are often used as lineage-specific markers. Antibodies that recognize cell surface antigens are widely used as research tools, diagnostic markers, and even therapeutic agents. The ability to obtain broad cell surface protein profiles would thus be of great value in a wide range of fields. There are however currently few available methods for high-throughput analysis of large numbers of cell surface proteins. We describe here a high-throughput flow cytometry (HT-FC) platform for rapid analysis of 363 cell surface antigens. Here we demonstrate that HT-FC provides reproducible results, and use the platform to identify cell surface antigens that are influenced by common cell preparation methods. We show that multiple populations within complex samples such as primary tumors can be simultaneously analyzed by co-staining of cells with lineage-specific antibodies, allowing unprecedented depth of analysis of heterogeneous cell populations. Furthermore, standard informatics methods can be used to visualize, cluster and downsample HT-FC data to reveal novel signatures and biomarkers. We show that the cell surface profile provides sufficient molecular information to classify samples from different cancers and tissue types into biologically relevant clusters using unsupervised hierarchical clustering. Finally, we describe the identification of a candidate lineage marker and its subsequent validation. In summary, HT-FC combines the advantages of a high-throughput screen with a detection method that is sensitive, quantitative, highly reproducible, and allows in-depth analysis of heterogeneous samples. The use of commercially available antibodies means that high quality reagents are immediately available for follow-up studies. HT-FC has a wide range of applications, including biomarker discovery, molecular classification of cancers, or identification of novel lineage specific or stem cell markers.     

Ultrastructural localization of proteoglycans in tissue using Cuprolinic Blue according to the critical electrolyte concentration method: Comparison with biochemical data from the literature

Summary Several connective tissues were stained for proteoglycans using the cationic dye Cuprolinic Blue according to the critical electrolyte concentration method. With this method, proteoglycans are visualized as electron-dense filaments. In most tissues, two types of proteoglycan filaments are present: a small (maximum length 60 nm), thin, collagen fibril-associated filament, and a thick, heavily-staining filament which is predominantly localized between bundles of collagen fibrils. Cartilage contains very large (about 300 nm) proteoglycan filaments while in cornea they are very small. Comparison with biochemical data from the literature suggests that the appearance of the proteoglycan filaments may be indicative for the glycosaminoglycan—protein ratio and for the molecular weight of the part of the protein core to which glycosaminoglycans are attached. The data thus obtained on the localization and structure of a proteoglycan may be useful when planning a strategy for its isolation.     

Evolution of base composition in the insulin and insulin-like growth factor genes

The genomes of homeothermic (warm-blooded) vertebrates are mosaic interspersions of homogeneously GC-rich and GC-poor regions (isochores). Evolution of genome compartmentalization and GC-rich isochores is hypothesized to reflect either selective advantages of an elevated GC content or chromosome location and mutational pressure associated with the timing of DNA replication in germ cells. To address the present controversy regarding the origins and maintenance of isochores in homeothermic vertebrates, newly obtained as well as published nucleotide sequences of the insulin and insulin-like growth factor (IGF) genes, members of a well-characterized gene family believed to have evolved by repeated duplication and divergence, were utilized to examine the evolution of base composition in nonconstrained (flanking) and weakly constrained (introns and fourfold degenerate sites) regions. A phylogeny derived from amino acid sequences supports a common evolutionary history for the insulin/IGF family genes. In cold- blooded vertebrates, insulin and the IGFs were similar in base composition. In contrast, insulin and IGF-II demonstrate dramatic increases in GC richness in mammals, but no such trend occurred in IGF- I. Base composition of the coding portions of the insulin and IGF genes across vertebrates correlated (r = 0.90) with that of the introns and flanking regions. The GC content of homologous introns differed dramatically between insulin/IGF-II and IGF-I genes in mammals but was similar to the GC level of noncoding regions in neighboring genes. Our findings suggest that the base composition of introns and flanking regions is determined by chromosomal location and the mutational pressure of the isochore in which the sequences are embedded. An elevated GC content at codon third positions in the insulin and the IGF genes may reflect selective constraints on the usage of synonymous codons.