Iron bioavailability in low phytate pea

Non-Peer ReviewedThe objectives of this study are to determine the effect of genotype and environment on iron bioavailability in a set of five pea varieties differing in phytate concentration using the in vitro digestion/Caco-2 human cell assay (Glahn 2009), to determine whether iron bioavailability in field pea is heritable by evaluating recombinant inbred lines (RILs) differing in phytate concentration using in vitro digestion/Caco-2 human cell assay, and to determine the effect of the pea low phytate trait on chicken performance and iron bioavailability in chicken. In a previous study, two low phytate pea lines (1-2347-144 and 1-150-81) were developed from CDC Bronco at the Crop Development Centre, University of Saskatchewan (Warkentin et al. 2012). As a powerful chelator of iron, phytate can reduce the iron bioavailability in diets. The low phytate peas may have increased iron bioavailability compared to the normal phytate peas. In the first objective of this project, the iron bioavailability of pea seeds of the two low phytate lines, their parent CDC Bronco and two other popular pea varieties in western Canada (CDC Meadow and CDC Golden), derived from 3 replicate field experiments conducted in 2009 and 2010 at SPG (Saskatchewan Pulse Growers land), Outlook and Rosthern, were assessed using the in vitro digestion/Caco-2 cell culture. The result shows that the iron bioavailability of the two low phytate lines is significantly higher than the other three normal phytate varieties, although their iron concentrations have not significant difference. The low phytate line 1-2347-144 and CDC Meadow were crossed to develop RILs

Iron bioavailability in low-phytate pea

Non-Peer ReviewedPhytate is the main storage form of phosphorus in the seeds of most crops. Phytate is not well digested by monogastrics and it chelates iron, zinc and some other micronutrients. To increase the nutritional value of pea seeds, two low phytate lines (1-150-81 and 1-2347-144) were developed from CDC Bronco in previous research. In this study, an in vitro digestion/Caco-2 cell culture bioassay was used to simulate the iron absorption of peas in humans, as the cell line originated from human colon adenocarcinoma cells. The iron bioavailability of the two low-phytate lines was 1.4 to 1.9 times higher than that of three normal phytate varieties, while having the same total iron concentration. In vivo studies were used to evaluate iron absorption of chickens fed low phytate and normal phytate pea diets. The diets containing the two low-phytate pea lines had no significant effect on chicken body weight and hemoglobin level, compared with the diets containing normal phytate pea cultivars, however, iron deficiency was suspected in all diets used

Iron bioavailability in two commercial cultivars of wheat: a comparison between wholegrain and white flour and the effects of nicotianamine and 2'-deoxymugineic acid on iron uptake into Caco-2 cells

Iron bioavailability in unleavened white and wholegrain bread made from two commercial wheat varieties was assessed by measuring ferritin production in Caco-2 cells. The breads were subjected to simulated gastrointestinal digestion and the digests applied to the Caco-2 cells. Although Riband grain contained a lower iron concentration than Rialto, iron bioavailability was higher. No iron was taken up by the cells from white bread made from Rialto flour or from wholegrain bread from either variety, but Riband white bread produced a small ferritin response. The results probably relate to differences in phytate content of the breads, although iron in soluble monoferric phytate was demonstrated to be bioavailable in the cell model. Nicotianamine, an iron chelator in plants involved in iron transport, was a more potent enhancer of iron uptake into Caco-2 cells than ascorbic acid or 2'-deoxymugineic acid, another metal chelator present in plants

Developing more environmentally friendly and nutritious pea varieties

Non-Peer ReviewedPhytate is the major storage form of phosphorus in crop seeds, but is not well digested by humans and non-ruminant animals. In addition, phytate chelates several essential micronutrients which are also excreted contributing to phosphorus pollution in the environment. Environmental and nutritional concerns led to the development of cultivars with the low phytate trait. The present study is aimed at biochemical and molecular characterization of two low phytate pea mutant lines, 1-150-81 and 1-2347-144 developed at the Crop Development Centre, University of Saskatchewan in collaboration with Dr. Victor Raboy, USDA, Idaho. Biochemical characterization is in progress for the two low phytate lines, their progenitor, CDC Bronco and CDC Meadow that were grown in replicated field trials at Saskatoon and Rosthern, SK in 2010 and 2011. Samples of developing seeds were collected 7 days after pollination and at weekly intervals thereafter until maturity. The concentration of phytate-phosphorus, isomeric forms of phytatephosphorus and inorganic phosphorus in these developing cotyledons and seed coats will be assessed using colorimetric and HPLC methods. In this way, the pattern of phytate-phosphorus and inorganic phosphorus accumulation will be determined in developing seeds. Molecular characterization will include cloning, sequencing and mapping of the gene(s) associated with the low phytate trait. Molecular markers will be developed based on the gene sequences. Recombinant inbred lines (RILs) were developed from crosses between the two low phytate lines and CDC Meadow. One set of RILs was evaluated in a field trial in Saskatchewan in 2011, and will be evaluated again in 2012. The RILs will be genotyped using available microsatellite markers or SNP markers and phenotyped using colorimetric and HPLC assays. These data will then be used to identify the molecular marker(s) for the trait. The study will aid us to understand the nature of the low phytate mutation(s). Significant potential benefits that we could expect out of the project include improved bioavailability of phosphorus, iron and zinc in foods and feeds, less phosphorus excretion and environmental pollution and a substantial saving in feed costs

Means and covariance functions for geostatistical compositional data: an axiomatic approach

This work focuses on the characterization of the central tendency of a sample of compositional data. It provides new results about theoretical properties of means and covariance functions for compositional data, with an axiomatic perspective. Original results that shed new light on the geostatistical modeling of compositional data are presented. As a first result, it is shown that the weighted arithmetic mean is the only central tendency characteristic satisfying a small set of axioms, namely continuity, reflexivity and marginal stability. Moreover, this set of axioms also implies that the weights must be identical for all parts of the composition. This result has deep consequences on the spatial multivariate covariance modeling of compositional data. In a geostatistical setting, it is shown as a second result that the proportional model of covariance functions (i.e., the product of a covariance matrix and a single correlation function) is the only model that provides identical kriging weights for all components of the compositional data. As a consequence of these two results, the proportional model of covariance function is the only covariance model compatible with reflexivity and marginal stability

Multi-Region Hemispheric Specialization Differentiates Human from Nonhuman Primate Brain Function

The human behavioral repertoire greatly exceeds that of nonhuman primates. Anatomical specializations of the human brain include an enlarged neocortex and prefrontal cortex (Semendeferi et al. in Am J Phys Anthropol 114:224–241, 2001), but regional enlargements alone cannot account for these vast functional differences. Hemispheric specialization has long believed to be a major contributing factor to such distinctive human characteristics as motor dominance, attentional control and language. Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization. Identifying the mechanisms that underlie these functional differences remains a goal of considerable interest. Here, we investigate the intrinsic connectivity networks in four primate species (humans, chimpanzees, baboons, and capuchin monkeys) using resting-state fMRI to evaluate the intra- and inter- hemispheric coherences of spontaneous BOLD fluctuation. All three nonhuman primate species displayed lateralized functional networks that were strikingly similar to those observed in humans. However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity. Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates

Serum phosphatidylinositol as a biomarker for bipolar disorder liability

Objectives Individuals with bipolar disorder (BPD) exhibit alterations in their phospholipid levels. It is unclear whether these alterations are a secondary consequence of illness state, or if phospholipids and illness risk overlap genetically. If the latter were true, then phospholipids might provide key insights into the pathophysiology of the illness. Therefore, we rank-ordered phospholipid classes by their genetic overlap with BPD risk in order to establish which class might be most informative in terms of increasing our understanding of illness pathophysiology. Methods Analyses were conducted in a sample of 558 individuals, unselected for BPD, from 38 extended pedigrees (average family size=14.79, range=2–82). We calculated a coefficient of relatedness for all family members of nine individuals with BPD in the sample (N=185); this coefficient was set to be zero in unrelated individuals (N=373). Then, under an endophenotype ranking value (ERV) approach, this scalar index was tested against 13 serum-based phospholipid concentrations in order to rank-order lipid classes by their respective overlap with BPD risk. Results The phosphatidylinositol class was significantly heritable (h2=0.26, P=6.71 × 10−05). It was the top-ranked class, and was significantly associated with BPD risk after correction for multiple testing (β=−1.18, P=2.10 × 10−03, ERV=0.49). Conclusions We identified a peripheral biomarker, serum-based phosphatidylinositol, which exhibits a significant association with BPD risk. Therefore, given that phosphatidylinositol and BPD risk share partially common etiology, it seems that this lipid class warrants further investigation, not only in terms of treatment, but also as a promising diagnostic and risk marker

The Lipidome in Major Depressive Disorder: Shared Genetic Influence for Ether-Phosphatidylcholines, a Plasma-Based Phenotype Related to Inflammation, and Disease Risk

Background The lipidome is rapidly garnering interest in the field of psychiatry. Recent studies have implicated lipidomic changes across numerous psychiatric disorders. In particular there is growing evidence that the concentrations of several classes of lipids are altered in those diagnosed with MDD. However, for lipidomic abnormalities to be considered potential treatment targets for MDD (rather than secondary manifestations of the disease), a shared etiology between lipid concentrations and MDD should be demonstrated. Methods In a sample of 567 individuals from 37 extended pedigrees (average size 13.57 people, range = 3–80), we used mass-spectrometry lipidomic measures to evaluate the genetic overlap between twenty-three biologically distinct lipid classes and a dimensional scale of MDD. Results We found that the lipid class with the largest endophenotype ranking value (ERV, a standardized parametric measure of pleiotropy) were ether-phosphodatidylcholines (alkylphosphatidylcholine, PC(O) and alkenylphosphatidylcholine, PC(P) subclasses). Furthermore, we examined the cluster structure of the twenty-five species within the top-ranked lipid class, and the relationship of those clusters with MDD. This analysis revealed that species containing arachidonic acid generally exhibited the greatest degree of genetic overlap with MDD. Conclusions This study is the first to demonstrate a shared genetic etiology between MDD and ether-phosphatidylcholine species containing arachidonic acid, an omega-6 fatty acid that is a precursor to inflammatory mediators, such as prostaglandins. The study highlights the potential utility of the well-characterized linoleic/arachidonic acid inflammation pathway as a diagnostic marker and/or treatment target for MDD

Family-based analyses reveal novel genetic overlap between cytokine interleukin-8 and risk for suicide attempt

Background: Suicide is major public health concern. It is imperative to find robust biomarkers so that at-risk individuals can be identified in a timely and reliable manner. Previous work suggests mechanistic links between increased cytokines and risk for suicide, but questions remain regarding the etiology of this association, as well as the roles of sex and BMI. Methods: Analyses were conducted using a randomly-ascertained extended-pedigree sample of 1882 Mexican-American individuals (60% female, mean age = 42.04, range = 18-97). Genetic correlations were calculated using a variance components approach between the cytokines TNF-α, IL-6 and IL-8, and Lifetime Suicide Attempt and Current Suicidal Ideation. The potentially confounding effects of sex and BMI were considered. Results: 159 individuals endorse a Lifetime Suicide Attempt. IL-8 and IL-6 shared significant genetic overlap with risk for suicide attempt (ρg = 0.49, pFDR = 7.67 × 10-03; ρg = 0.53, pFDR = 0.01), but for IL-6 this was attenuated when BMI was included as a covariate (ρg = 0.37, se = 0.23, pFDR = 0.12). Suicide attempts were significantly more common in females (pFDR = 0.01) and the genetic overlap between IL-8 and risk for suicide attempt was significant in females (ρg = 0.56, pFDR = 0.01), but not in males (ρg = 0.44, pFDR = 0.30). Discussion: These results demonstrate that: IL-8 shares genetic influences with risk for suicide attempt; females drove this effect; and BMI should be considered when assessing the association between IL-6 and suicide. This finding represents a significant advancement in knowledge by demonstrating that cytokine alterations are not simply a secondary manifestation of suicidal behavior, but rather, the pathophysiology of suicide attempts is, at least partly, underpinned by the same biological mechanisms responsible for regulating inflammatory response