Pruebas no invasivas para el tamizaje del cáncer colon: fundamentos básico-clínicos y recientes avances biotecnológicos / Non-invasive tests for colorectal cancer screening: basic-clinical fundamentals and recent biotechnological advances

Colorectal Cancer (CRC) is the third most frequent neoplasia worldwide. Despite the significant advances in surgical techniques and the development of new targeted antineoplastic therapies for this type of tumor, primary prevention and early diagnosis of malignant precursor lesions will continue to be the best strategies to reduce their incidence, morbidity, and mortality. Technologies for CRC screening can be classified into two groups, those of an invasive nature, such as colonoscopy and all its different modalities of use, and those of a non-invasive nature, such as laboratory tests and imaging. This review, will focus exclusively on non-invasive screening tests, excluding imaging. Specifically, it will address those that use depositions as a sample. This review will approach the latest international recommendations, regarding the age at which they should be used, their technical-biological bases, the two main types currently used (biochemical and immunological), and we will put into perspective their advantages and their possible disadvantages. Towards the end of this article, the most recent biotechnological developments in relation to molecular tests based on the study of blood samples, will be discussed. Although these tests are not yet in routine clinical use given their high costs, they are promising for the early detection of CRC.

El cáncer colorrectal (CCR) es la tercera neoplasia más común en todo el mundo. A pesar de los avances significativos en las técnicas quirúrgicas y en el desarrollo de nuevas terapias antineoplásicas para este tipo de tumor, la prevención primaria y el diagnóstico precoz de lesiones precursoras malignas siguen siendo las mejores estrategias para reducir la incidencia, morbilidad y mortalidad asociadas al CCR. Existen dos tipos de tecnologías para el tamizaje del CCR: las invasivas, como la colonoscopia, y las no invasivas, como los ensayos de laboratorio y la imagenología. Esta revisión, se centrará exclusivamente en las pruebas de tamizaje no invasivas que utilizan muestras de deposiciones, excluyendo las imágenes. Se abordarán las últimas recomendaciones internacionales sobre el momento etario en que se deben utilizar, sus bases técnico-biológicas, los dos principales tipos utilizados en la actualidad (bioquímico e inmunológico) y pondremos en perspectiva sus ventajas y posibles desventajas. Al final de esta revisión, se discutirá brevemente los últimos avances biotecnológicos relacionados con pruebas moleculares basadas en el estudio de muestras sanguíneas. Aunque estas pruebas aún no son de uso clínico habitual debido a sus altos costos, representan una prometedora innovación para la detección temprana del CCR.

Emotional Content Modulates Attentional Visual Orientation During Free Viewing of Natural Images.

Visual attention is the process that enables us to select relevant visual stimuli in our environment to achieve a goal or perform adaptive behaviors. In this process, bottom-up mechanisms interact with top-down mechanisms underlying the automatic and voluntary orienting of attention. Cognitive functions, such as emotional processing, can influence visual attention by increasing or decreasing the resources destined for processing stimuli. The relationship between attention and emotion has been explored mainly in the field of automatic attentional capturing; especially, emotional stimuli are suddenly presented and detection rates or reaction times are recorded. Unlike these paradigms, natural visual scenes may be comprised in multiple stimuli with different emotional valences. In this setting, the mechanisms supporting voluntary visual orientation, under the influence of the emotional components of stimuli, are unknown. We employed a mosaic of pictures with different emotional valences (positive, negative, and neutral) and explored the dynamics of attentional visual orientation, assessed by eye tracking and measurements of pupil diameter. We found that pictures with affective content display increased dwelling times when compared to neutral pictures with a larger effect for negative pictures. The valence, regardless of the arousal levels, was the main factor driving the behavioral modulation of visual orientation. On the other hand, the visual exploration was accompanied by a systematic pupillary response, with the pupil contraction and dilation influenced by the arousal levels, with minor effects driven by the valence. Our results emphasize that arousal and valence should be considered different dimensions of emotional processing both interacting with cognitive processes such as visual attention.

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.).

KEY MESSAGE: Twelve meta-QTL for seed Fe and Zn concentration and/or content were identified from 87 QTL originating from seven population grown in sixteen field trials. These meta-QTL include 2 specific to iron, 2 specific to zinc and 8 that co-localize for iron and zinc concentrations and/or content. Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification breeding programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrient deficiencies. Biofortification efforts thus far have relied on phenotypic selection of raw seed mineral concentrations in advanced generations. While numerous quantitative trait loci (QTL) studies have been conducted to identify genomic regions associated with increased Fe and Zn concentration in seeds, these results have yet to be employed for marker-assisted breeding. The objective of this study was to conduct a meta-analysis from seven QTL studies in Andean and Middle American intra- and inter-gene pool populations to identify the regions in the genome that control the Fe and Zn levels in seeds. Two meta-QTL specific to Fe and two meta-QTL specific to Zn were identified. Additionally, eight Meta QTL that co-localized for Fe and Zn concentration and/or content were identified across seven chromosomes. The Fe and Zn shared meta-QTL could be useful candidates for marker-assisted breeding to simultaneously increase seed Fe and Zn. The physical positions for 12 individual meta-QTL were identified and within five of the meta-QTL, candidate genes were identified from six gene families that have been associated with transport of iron and zinc in plants.

Repetitive Intermittent Hypoxia and Locomotor Training Enhances Walking Function in Incomplete Spinal Cord Injury Subjects: A Randomized, Triple-Blind, Placebo-Controlled Clinical Trial.

Incomplete spinal cord injuries (iSCI) leave spared synaptic pathways below the level of injury. Intermittent hypoxia (IH) elicits plasticity in the spinal cord and strengthens spared synaptic pathways, expressed as respiratory and somatic functional recovery in experimental animals and humans with iSCI. This study is a randomized, triple-blind, two-arm parallel clinical trial performed in Santiago, Chile. We compared the effects of a 4-week protocol of IH combined with body weight-supported treadmill training (BWSTT), with continuous normoxia (Nx) and BWSTT on 10-meter walk test (10MWT), 6-minute walk test (6MWT), and timed up and go (TUG) test in American Spinal Injury Association C and D individuals with iSCI. Subjects received daily IH (cycling 9%/21% O2 every 1.5 min, 15 cycles/day) or continuous Nx (21% O2) combined with 45 min BWSTT for 5 consecutive days, followed by IH/Nx 3 × per week (3 × wIH/Nx) for 3 additional weeks. Subjects were assessed at day 5, weekly from weeks 2-4, and at a 2-week follow-up. Daily IH plus BWSTT enhanced walking speed, expressed as decreased 10MWT time at day 5 versus baseline (IH: -10.2 ± 3.0 vs. Nx: -1.7 ± 1.7 sec, p = 0.006), and walking endurance expressed as increased 6MWT distance at day 5 versus baseline (IH: 43.0 ± 10.7 vs. Nx: 6.1 ± 3.4 m, p = 0.012), but not TUG time. Further, 3 × wIH maintained the daily IH-induced walking speed, and enhanced the daily IH-induced walking endurance, which is maintained up to the 2-week follow-up. We conclude that daily IH enhances walking recovery in subjects with iSCI, confirming previous findings. Moreover, 3 × wIH prolonged or enhanced daily IH-induced walking speed and endurance improvements, respectively, up to 5 weeks post-daily IH. Repetitive IH may be a safe and effective therapeutic alternative for persons with iSCI.

Performance of an ultrafiltration membrane bioreactor (UF-MBR) as a processing strategy for the synthesis of galacto-oligosaccharides at high substrate concentrations.

The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synthesis using high lactose concentrations (470 g/L) and ß-galactosidase from Aspergillus oryzae was assessed. Tested processing variables were: transmembrane-pressure (PT), crossflow-velocity (CFV) and temperature. Results showed that processing variables had significant effect on the yield, the enzyme productivity and the flux but did not on GOS concentration and reaction conversion obtained. As expected, the use of high turbulences improved mass transfer and reduced the membrane fouling, but the use of very high crossflow-velocities caused operational instability due to vortex formation and lactose precipitation. The use of a desirability function allowed determining optimal conditions which were: PT (4.38 bar), CFV (7.35 m/s) and temperature (53.1 °C), optimizing simultaneously flux and specific enzyme productivity Under these optimal processing conditions, shear-stress and temperature did not affect the enzyme but long-term operation was limited by flux decay. In comparison to a conventional batch system, at 12.5h of processing time, the continuous GOS synthesis in the UF-MBR increased significantly the amount of processed substrate and a 2.44-fold increase in the amount of GOS produced per unit mass of catalyst was obtained with respect to a conventional batch system. Furthermore, these results can be improved by far by tuning the membranearea/reactionvolume ratio, showing that the use of an UF-MBR is an attractive alternative for the GOS synthesis at very high lactose concentrations.

Genetic Dissection of ICP-Detected Nutrient Accumulation in the Whole Seed of Common Bean (Phaseolus vulgaris L.).

Nutrient transport to grain legume seeds is not well studied and can benefit from modern methods of elemental analysis including spectroscopic techniques. Some cations such as potassium (K) and magnesium (Mg) are needed for plant physiological purposes. Meanwhile, some minerals such as copper (Cu), iron (Fe), molybdenum (Mo), and zinc (Zn) are important micronutrients. Phosphorus (P) is rich in legumes, while sulfur (S) concentration is related to essential amino acids. In this research, the goal was to analyze a genetic mapping population of common bean (Phaseolus vulgaris L.) with inductively coupled plasma (ICP) spectrophotometry to determine concentrations of and to discover quantitative trait loci (QTL) for 15 elements in ground flour of whole seeds. The population was grown in randomized complete block design experiments that had been used before to analyze Fe and Zn. A total of 21 QTL were identified for nine additional elements, of which four QTL were found for Cu followed by three each for Mg, Mn, and P. Fewer QTL were found for K, Na and S. Boron (B) and calcium (Ca) had only one QTL each. The utility of the QTL for breeding adaptation to element deficient soils and association with previously discovered nutritional loci are discussed.

COST-EFFECTIVENESS OF EARLY NUTRITIONAL THERAPY IN MALNOURISHED ADULT PATIENTS IN A HIGH COMPLEXITY HOSPITAL.

INTRODUCTION: hospital malnutrition is a frequent worldwide problem and its potential issues related include increased complications, length of stay, mortality, and healthcare costs. OBJECTIVES: the aim of this study was to establish the cost-effectiveness of early nutritional therapy for malnourished patients in a high complexity hospital. MATERIALS AND METHODS: this analytical study with economic assessment included 227 adult hospitalised and malnourished according to the Subjective Global Assessment. The cohort prospective received Early Nutrition Therapy (ENT), whereas the cohort retrospective received Delayed Nutrition Therapy (DNT). The measures of cost-effectiveness included costs by: length of stay, complications and discharge condition. RESULTS: the cohorts were similar in demographic and clinical characteristics, except that the median age, for the ENT was 61 years (interquartile range [IQR]: 48-71) and for the DNT was 55 years (IQR: 44-67) (p = 0.024). The median length of stay was lower in the ENT (11 days, IQR: 7-17) than in the DNT (18 days, IQR: 10-28) (p < 0.001). The cost per patient discharged alive was US $ 10,261.55 in the ENT and US $ 15,553.11 in the DNT (p=0.043); the cost per patient with complications was US $ 13,663.90 in the ENT and US $ 17,860.32 in the DNT (p= 0.058). ENT increased the likelihood of being discharged alive, RR adjusted=0.31; 95% confidence interval (CI): 0.1; 0.6; (p<0.001) and decreased the likelihood of complications RR crude=0.8; 95% CI: 0.6; 0.9; (p=0.006). CONCLUSION: early nutritional therapy for malnourished adult patients appears to be cost-effective because it can reduce the length of stay, complications, mortality and associated costs.

Introducción: la malnutrición hospitalaria es un problema frecuente en el mundo que aumenta las complicaciones, los días de estancia, la mortalidad y los costes sanitarios. Objetivos: el objetivo de este estudio fue establecer la coste-efectividad de la terapia nutricional precoz en pacientes malnutridos en un hospital de alta complejidad. Materiales y métodos: este estudio analítico con valoración económica, incluyó 227 adultos hospitalizados y malnutridos según Valoración Global Subjetiva. La cohorte prospectiva recibió Terapia Nutricional Precoz (TNP), mientras que la cohorte retrospectiva recibió Terapia Nutricional Tardía (TNT). Las medidas del coste- efectividad incluyeron costes por: días de estancia, complicaciones y condición de egreso. Resultados: las cohortes fueron similares en cuanto a características clínicas y demográficas, excepto en la mediana de edad; para la TNP fue 61 años (rango intercuartil [RIQ]: 48-71) y para la TNT fue 55 años (RIQ: 44-67) (p=0,024). La TNP se encontró costo-efectiva en la reducción de los días de estancia hospitalaria (11 días, RIQ: 7-17) en comparación con la TNT (18 días, RIQ: 10-28) (p.

Cost-effectiveness of early nutritional therapy in malnourished adult patients in a high complexity hospital / Coste-efectividad de la terapia nutricional temprana en pacientes adultos malnutridos en un hospital de alta complejidad

Introduction: hospital malnutrition is a frequent worldwide problem and its potential issues related include increased complications, length of stay, mortality, and healthcare costs. Objectives: the aim of this study was to establish the cost-effectiveness of early nutritional therapy for malnourished patients in a high complexity hospital. Materials and methods: this analytical study with economic assessment included 227 adult hospitalised and malnourished according to the Subjective Global Assessment. The cohort prospective received Early Nutrition Therapy (ENT), whereas the cohort retrospective received Delayed Nutrition Therapy (DNT). The measures of cost-effectiveness included costs by: length of stay, complications and discharge condition. Results: the cohorts were similar in demographic and clinical characteristics, except that the median age, for the ENT was 61 years (interquartile range [IQR]: 48-71) and for the DNT was 55 years (IQR: 44-67) (p = 0.024). The median length of stay was lower in the ENT (11 days, IQR: 7-17) than in the DNT (18 days, IQR: 10-28) (p < 0.001). The cost per patient discharged alive was US $ 10,261.55 in the ENT and US $ 15,553.11 in the DNT (p=0.043); the cost per patient with complications was US $ 13,663.90 in the ENT and US $ 17,860.32 in the DNT (p= 0.058). ENT increased the likelihood of being discharged alive, RR adjusted=0.31; 95% confidence interval (CI): 0.1; 0.6; (p<0.001) and decreased the likelihood of complications RR crude=0.8; 95% CI: 0.6; 0.9; (p=0.006). Conclusion: early nutritional therapy for malnourished adult patients appears to be cost-effective because it can reduce the length of stay, complications, mortality and associated costs (AU)

Introducción: la malnutrición hospitalaria es un problema frecuente en el mundo que aumenta las complicaciones, los días de estancia, la mortalidad y los costes sanitarios. Objetivos: el objetivo de este estudio fue establecer el coste-efectividad de la terapia nutricional precoz en pacientes malnutridos en un hospital de alta complejidad. Materiales y métodos: este estudio analítico con valoración económica, incluyó 227 adultos hospitalizados y malnutridos según Valoración Global Subjetiva. La cohorte prospectiva recibió Terapia Nutricional Precoz (TNP), mientras que la cohorte retrospectiva recibió Terapia Nutricional Tardía (TNT). Las medidas del coste-efectividad incluyeron costes por: días de estancia, complicaciones y condición de egreso. Resultados: las cohortes fueron similares en cuanto a características clínicas y demográficas, excepto en la mediana de edad; para la TNP fue 61 años (rango intercuartil [RIQ]: 48-71) y para la TNT fue 55 años (RIQ: 44-67) (p=0,024). La TNP se encontró costo-efectiva en la reducción de los días de estancia hospitalaria (11 días, RIQ: 7-17) en comparación con la TNT (18 días, RIQ: 10-28) (p<0,001). La TNP registró costos de 10.261,55 $ US por paciente egresado vivo, inferiores a los obtenidos en la TNT 15.553,11 $ US (p=0,043); el coste por paciente con complicaciones fue 13.663,90 $ US en la TNP y 17.860,32 $ US en la TNT (p=0,058). La TNP incrementó la probabilidad de egresar vivo, RR ajustado=0,31; intervalo de confianza (IC) 95%: 0,1; 0,6; (p<0,001) y disminuyó la probabilidad de complicaciones RR crudo=0,8; IC 95%: 0,6; 0,9; (p=0,006). Conclusión: la terapia nutricional precoz en pacientes adultos malnutridos parece ser coste-efectiva porque puede reducir los días de estancia, las complicaciones, la mortalidad y los costes asociados (AU)

A legume biofortification quandary: variability and genetic control of seed coat micronutrient accumulation in common beans.

Common beans (Phaseolus vulgaris L.), like many legumes, are rich in iron, zinc, and certain other microelements that are generally found to be in low concentrations in cereals, other seed crops, and root or tubers and therefore are good candidates for biofortification. But a quandary exists in common bean biofortification: namely that the distribution of iron has been found to be variable between the principal parts of seed; namely the cotyledonary tissue, embryo axis and seed coat. The seed coat represents ten or more percent of the seed weight and must be considered specifically as it accumulates much of the anti-nutrients such as tannins that effect mineral bioavailability. Meanwhile the cotyledons accumulate starch and phosphorus in the form of phytates. The goal of this study was to evaluate a population of progeny derived from an advanced backcross of a wild bean and a cultivated Andean bean for seed coat versus cotyledonary minerals to identify variability and predict inheritance of the minerals. We used wild common beans because of their higher seed mineral concentration compared to cultivars and greater proportion of seed coat to total seed weight. Results showed the most important gene for seed coat iron was on linkage group B04 but also identified other QTL for seed coat and cotyledonary iron and zinc on other linkage groups, including B11 which has been important in studies of whole seed. The importance of these results in terms of physiology, candidate genes and plant breeding are discussed.

The Phaseolus vulgaris ZIP gene family: identification, characterization, mapping, and gene expression.

Zinc is an essential mineral for humans and plants and is involved in many physiological and biochemical processes. In humans, Zn deficiency has been associated with retarded growth and reduction of immune response. In plants, Zn is an essential component of more than 300 enzymes including RNA polymerase, alkaline phosphatase, alcohol dehydrogenase, Cu/Zn superoxidase dismutase, and carbonic anhydrase. The accumulation of Zn in plants involves many genes and characterization of the role of these genes will be useful in biofortification. Here we report the identification and phlyogenetic and sequence characterization of the 23 members of the ZIP (ZRT, IRT like protein) family of metal transporters and three transcription factors of the bZIP family in Phaseolus vulgaris L. Expression patterns of seven of these genes were characterized in two bean genotypes (G19833 and DOR364) under two Zn treatments. Tissue analyzed included roots and leaves at vegetative and flowering stages, and pods at 20 days after flowering. Four of the genes, PvZIP12, PvZIP13, PvZIP16, and Pv bZIP1, showed differential expression based on tissue, Zn treatment, and/or genotype. PvZIP12 and PvZIP13 were both more highly expressed in G19833 than DOR364. PvZIP12 was most highly expressed in vegetative leaves under the Zn (-) treatment. PvZIP16 was highly expressed in leaf tissue, especially leaf tissue at flowering stage grown in the Zn (-) treatment. Pv bZIP1 was most highly expressed in leaf and pod tissue. The 23 PvZIP genes and three bZIP genes were mapped on the DOR364 × G19833 linkage map. PvZIP12, PvZIP13, and PvZIP18, Pv bZIP2, and Pv bZIP3 were located near QTLs for Zn accumulation in the seed. Based on the expression and mapping results, PvZIP12 is a good candidate gene for increasing seed Zn concentration and increase understanding of the role of ZIP genes in metal uptake, distribution, and accumulation of zinc in P. vulgaris.

Variation and inheritance of iron reductase activity in the roots of common bean (Phaseolus vulgaris L.) and association with seed iron accumulation QTL.

BACKGROUND: Iron deficiency anemia is a global problem which often affects women and children of developing countries. Strategy I plants, such as common bean (Phaseolus vulgaris L.) take up iron through a process that involves an iron reduction mechanism in their roots; this reduction is required to convert ferric iron to ferrous iron. Root absorbed iron is critical for the iron nutrition of the plant, and for the delivery of iron to the shoot and ultimately the seeds. The objectives of this study were to determine the variability and inheritance for iron reductase activity in a range of genotypes and in a low × high seed iron cross (DOR364 x G19833), to identify quantitative trait loci (QTL) for this trait, and to assess possible associations with seed iron levels. RESULTS: The experiments were carried out with hydroponically grown plants provided different amounts of iron varying between 0 and 20 µM Fe(III)-EDDHA. The parents, DOR364 and G19833, plus 13 other cultivated or wild beans, were found to differ in iron reductase activity. Based on these initial experiments, two growth conditions (iron limited and iron sufficient) were selected as treatments for evaluating the DOR364 × G19833 recombinant inbred lines. A single major QTL was found for iron reductase activity under iron-limited conditions (1 µM Fe) on linkage group b02 and another major QTL was found under iron sufficient conditions (15 µM Fe) on linkage group b11. Associations between the b11 QTL were found with several QTL for seed iron. CONCLUSIONS: Genes conditioning iron reductase activity in iron sufficient bean plants appear to be associated with genes contributing to seed iron accumulation. Markers for bean iron reductase (FRO) homologues were found with in silico mapping based on common bean synteny with soybean and Medicago truncatula on b06 and b07; however, neither locus aligned with the QTL for iron reductase activity. In summary, the QTL for iron reductase activity under iron limited conditions may be useful in environments where beans are grown in alkaline soils, while the QTL for iron reductase under sufficiency conditions may be useful for selecting for enhanced seed nutritional quality.

QTL for seed iron and zinc concentration and content in a Mesoamerican common bean (Phaseolus vulgaris L.) population.

Iron and zinc deficiencies are human health problems found throughout the world and biofortification is a plant breeding-based strategy to improve the staple crops that could address these dietary constraints. Common bean is an important legume crop with two major genepools that has been the focus of genetic improvement for seed micronutrient levels. The objective of this study was to evaluate the inheritance of seed iron and zinc concentrations and contents in an intra-genepool Mesoamerican × Mesoamerican recombinant inbred line population grown over three sites in Colombia and to identify quantitative trait loci (QTL) for each mineral. The population had 110 lines and was derived from a high-seed iron and zinc climbing bean genotype (G14519) crossed with a low-mineral Carioca-type, prostrate bush bean genotype (G4825). The genetic map for QTL analysis was created from SSR and RAPD markers covering all 11 chromosomes of the common bean genome. A set of across-site, overlapping iron and zinc QTL was discovered on linkage group b06 suggesting a possibly pleiotropic locus and common physiology for mineral uptake or loading. Other QTL for mineral concentration or content were found on linkage groups b02, b03, b04, b07, b08 and b11 and together with the b06 cluster were mostly novel compared to loci found in previous studies of the Andean genepool or inter-genepool crosses. The discovery of an important new locus for seed iron and zinc concentrations may facilitate crop improvement and biofortification using the high-mineral genotype especially within the Mesoamerican genepool.

Iron and ferritin accumulate in separate cellular locations in Phaseolus seeds.

BACKGROUND: Iron is an important micronutrient for all living organisms. Almost 25% of the world population is affected by iron deficiency, a leading cause of anemia. In plants, iron deficiency leads to chlorosis and reduced yield. Both animals and plants may suffer from iron deficiency when their diet or environment lacks bioavailable iron. A sustainable way to reduce iron malnutrition in humans is to develop staple crops with increased content of bioavailable iron. Knowledge of where and how iron accumulates in seeds of crop plants will increase the understanding of plant iron metabolism and will assist in the production of staples with increased bioavailable iron. RESULTS: Here we reveal the distribution of iron in seeds of three Phaseolus species including thirteen genotypes of P. vulgaris, P. coccineus, and P. lunatus. We showed that high concentrations of iron accumulate in cells surrounding the provascular tissue of P. vulgaris and P. coccineus seeds. Using the Perls' Prussian blue method, we were able to detect iron in the cytoplasm of epidermal cells, cells near the epidermis, and cells surrounding the provascular tissue. In contrast, the protein ferritin that has been suggested as the major iron storage protein in legumes was only detected in the amyloplasts of the seed embryo. Using the non-destructive micro-PIXE (Particle Induced X-ray Emission) technique we show that the tissue in the proximity of the provascular bundles holds up to 500 microg g(-1) of iron, depending on the genotype. In contrast to P. vulgaris and P. coccineus, we did not observe iron accumulation in the cells surrounding the provascular tissues of P. lunatus cotyledons. A novel iron-rich genotype, NUA35, with a high concentration of iron both in the seed coat and cotyledons was bred from a cross between an Andean and a Mesoamerican genotype. CONCLUSIONS: The presented results emphasize the importance of complementing research in model organisms with analysis in crop plants and they suggest that iron distribution criteria should be integrated into selection strategies for bean biofortification.