Dephytinization of a rat diet

Soaking of a rat diet, high in both plant phytate and phytase, progressively degraded the phytate content with time of soaking. This dephytinization in turn enhanced the digestion of feed organic matter in the animals, and it significantly improved the absorption and retention of minerals and trace elements as observed in balance studies. Incorporation of elements into specific tissues was evaluated as a reflection of bioavailability. Some tissues did reflect the preceding absorption of certain elements; other tissues seemed less suitable as indicators of trace element absorption. Dietary calcium addition in many ways contrasted the soaking procedure: inorganic calcium addition to the feed reduced phosphorus, magnesium, and trace element bioavailability, and interfered with the internal deposition of the elements. The external dephytinization of the feed did not affect the phosphohydrolase activity of the intestinal mucosa as manifested by alkaline phosphatase activity or phytase activity. The mucosal phytase and alkaline phosphatase activities were, however, mutually correlated, supporting the view that “phytase” activity is a less substratespecific action of alkaline phosphatase activity or a fraction of this activity.     

Dialyzability of iron, zinc, and copper of different types of infant formulas marketed in Spain

The bioavailability of trace elements in infant formulas is affected by different physiological and dietetic factors. In vitro methods based on element dialyzability have been proposed to estimate the bioavailability. Infant formulas of the same type but from different manufacturers can differ in the salt used for supplementation and in the contents of other components that can affect mineral bioavailability. The aim of our study is to estimate the dialyzability of iron, zinc, and copper of formulas marketed in Spain, in order to detect possible differences in formulas of the same type coming from different manufacturers. At the same time, the effects of the type of formula, the composition of the protein fraction, and the mineral content on the element dialyzability are also studied. Differences are found in the dialysis percentages of the elements studied in formulas of the same type but from different manufacturers. The formulas giving the highest dialysis percentages for the three considered elements are the hypoallergenic ones based on protein hydrolysates. No differences are observed in formulas having whey or casein as the main protein fraction. Significant correlations are obtained between the element contents and the dialyzability of the elements.     

Multielement stoichiometry in aquatic invertebrates: when growth dilution matters

Element concentrations in organisms can be variable, often causing deviations from otherwise consistent, taxon-specific multielement stoichiometries. Such variation can have considerable ecological consequences, yet physiological mechanisms remain unclear. We tested the influence of somatic growth dilution (SGD) on multiple element concentrations under different bioenergetic conditions. SGD occurs when rapid individual growth causes a disproportional gain in biomass relative to gain of a specific element. SGD can strongly affect elements in various organisms, but we lack a general framework to unify results across studies and assess its overall importance. We derived the general conditions that trigger SGD from an element accumulation model. We parameterized the model with bioenergetic and element-specific rates summarized from the literature to compare SGD effects on 15 elements (nonessential metals, essential trace elements, macronutrients) in three aquatic invertebrate taxa. For all taxa, we found that SGD (1) occurs to some degree for all 15 elements over realistic ranges of growth and ingestion rates and (2) has the greatest effect on elements with low efflux (excretion) rates, including certain nonessential metals (e.g., MeHg, Po), essential trace elements, and macronutrients (e.g., N, Fe). Thus, SGD can strongly affect concentrations of a spectrum of elements under natural conditions. These results provide a framework for predicting variation in the elemental composition of animals.     

The SET and ERITME indices: Integrative tools for the management of polluted sites

To address the lack of biological methods for assessing soil quality and its contaminant retention capacity and to provide a tool with which stakeholders can assess the risk of transfer of trace elements in the soil to the soil fauna, the Sum of the Excess of Transfers (SET) index from soil to the snail Cantareus aspersus has been broadened to include the internal concentrations of reference (CIRef) for 14 metals and metalloids (As, Cd, Co, Cu, Cr, Hg, Mo, Ni, Pb, Sb, Sn, Sr, Tl and Zn). Weighting the transfer of these elements by a risk coefficient (i.e., their toxicity point) provides a new assessment tool for stakeholders: the ERITME (Evaluation of the Risk of the Transferred Metal Elements) tool. This upgraded tool has been used to highlight unsuspected risks and revise management priorities at an industrial site. Moreover, using the tool to determine the risk from metal trace elements allows for improved environmental risk assessment, as ERITME is an integrative tool based on the real bioavailability of metals rather than chemical measures that often lead to unsatisfactory assessments of transfer. The SET and ERITME integrative tools, using snails as indicators of trace element zooavailability, can be used in environmental risk assessment.     

Speciation of trace element compounds in samples of biota from marine ecosystems

Abstract

The toxicity, mobility, bioavailability and bioaccumulation of metals are dependent on the particular physico-chemical form in which the element occurs in the environment. Special attention has been paid to metals which are essential for the proper functioning of organisms if present in appropriate amounts but are toxic if in excess (i.e. Se, Cr), and also to non-essential elements (i.e. Hg, Pb, Cd, Sn and As). To assess the potential hazard to the health of marine organisms, qualitative and quantitative analyses of metal species accumulating along the food chain needs to be carried out. This paper reviews the available information on the speciation of trace elements in the food chain in marine ecosystems and the analytical tools used for acquiring reliable information in this field. Advantages and limitations of commonly used techniques indicate that all metal species in different samples need diverse extraction, separation and detection conditions. Although not recommending which procedure is the most suitable to determine a given compound, speciation analysis has the potential to be a powerful tool for the identification of trace element species in biological samples.     

Effects of nitrogen and water addition on trace element stoichiometry in five grassland species

A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants under the two environmental change factors in a semi-arid grassland of Inner Mongolia. We measured concentrations of trace elements in soil and in foliage of five common herbaceous species including 3 forbs and 2 grasses. In addition, bioaccumulation factors (BAF, the ratio of the chemical concentration in the organism and the chemical concentration in the growth substrate) and foliar Fe:Mn ratio in each plant was calculated. Our results showed that soil available Fe, Mn and Cu concentrations increased under N addition and were negatively correlated with both soil pH and cation exchange capacity. Water addition partly counteracted the positive effects of N addition on available trace element concentrations in the soil. Foliar Mn, Cu and Zn concentrations increased but Fe concentration decreased with N addition, resulting in foliar elemental imbalances among Fe and other selected trace elements. Water addition alleviated the effect of N addition. Forbs are more likely to suffer from Mn toxicity and Fe deficiency than grass species, indicating more sensitivity to changing elemental bioavailability in soil. Our results suggested that soil acidification due to N deposition may accelerate trace element cycling and lead to elemental imbalance in soil–plant systems of semi-arid grasslands and these impacts of N deposition on semi-arid grasslands were affected by water addition. These findings indicate an important role for soil trace elements in maintaining ecosystem functions associated with atmospheric N deposition and changing precipitation regimes in the future.     

Effect of digestive site acidity and compatibility on the species, lipopily and bioavailability of iron, manganese and zinc in Prunus persica Batsch and Carthamus tinctorus

The effects of compatibility, that is combination of Prunus persica Batsch (L.) and Carthamus tinctorus (L.), and different acidity of digestive site on the species, lipopily and bioavailability of coordinated complex of iron, manganese, and zinc in medical decoction were studied. In view of octanol, a long-chain alkanol, resembled as the configuration of carbohydrate and adipose in human body, the octanol- and water-solubility were used to define the species of trace element in phytomedicine, to identify the lipopily and bioavailability of trace element, and octanol-water system was adopted to study the distribution of trace element in decoction of P. persica Batsch (L.) (A), C. tinctorus (L.) (B), and combination of medicine A and B (C) in stomach and intestine. The total concentration, water- and octanol-solubility concentration of iron, manganese, and zinc in medicinal material A, B and C or its decoction under gastric and intestinal acidity, were determined respectively by flame atomic absorption spectrometry, analyzed and compared. The compatibility of medicine A and B enhances the extract percent, octanol-solubility concentration, and stability of coordinated complex of iron, manganese, and zinc. Different acidity of digestive site and compatibility of medicines impact on the ligands of iron, manganese, and zinc, then greatly affect the species and its quantification, the lipopily and bioavailability of trace element. Such influence is quite different for different trace element. Such factors, especially the concentration of octanol-solubility trace element, could be the basis of the dosage to avoid trace element overload.     

Role of nuclear analytical probe techniques in biological trace-element research

Many biomedical experiments require the qualitative and quantitative localization of trace elements with high sensitivity and good spatial resolution. The feasibility of measuring the chemical form of the elements, the time course of trace element metabolism, and conducting experiments in living biological systems are also important requirements for biological trace element research. Nuclear analytical techniques that employ ion or photon beams have grown in importance in the past decade and have led to several new experimental approaches. Some of the important features of these methods are reviewed here along with their role in trace element research. Examples of their use are given to illustrate potential for new research directions. It is emphasized that the effective application of these methods necessitates a closely integrated multidisciplinary scientific team.     

微量元素蛋白质组的比较基因组学研究

微量元素指需要量很少（人体中含量在0．01％以下）,但却是所有生物体所必需的元素。它们参与了生物体中各种复杂的生物过程,因此不同生物必须依赖相应的微量元素才能生存。过去大量的工作主要放在微量元素代谢通路和微量元素结合蛋白的实验研究上,由此凸显出微量元素对生命的重要性。然而,微量元素的计算生物学研究工作却非常有限。着重介绍当前利用比较基因组学的理论和方法来研究不同微量元素的利用、代谢、功能和进化方面问题的最新进展。对于所讨论的元素,大多数利用它们的蛋白已经基本确定,并且这些蛋白对于特定元素的依赖性也是非常保守的。通过比较基因组学分析,有助于帮助我们进一步认识微量元素领域很多基本问题（如在古菌、细菌和真核生物中的代谢、功能和动态进化规律等）及其重要特征。     

Multivariate statistical analysis of nutrients and trace elements in plants and soil from northwestern Russia

Results are summarized of several field and greenhouse experiments designed to estimate differences in the ability of some plant species to take up from soil essential nutrients and various trace elements and transfer them from roots to upper plant parts. Instrumental neutron activation analysis was used to determine concentrations of 22 elements in plant and soil samples. Correlation and principal component analysis were applied for interpreting a large volume of experimental results. In many cases there was no statistically significant positive correlation between element concentrations in soil and concentrations of these elements in plants. Moreover, relationships between elements were often different in soil and in different plant parts, thereby suggesting quite different element behaviours in soil and in plants. Our experimental results and data published in the literature revealed that macro- and trace element concentrations might serve as a specific indicator of plant taxonomy, thus allowing for differentiation of the plants in accordance with concentrations of certain elements in roots or in leaves. Short-term variations in concentrations of elements typical for different plant species and factors affecting these variations indicated that diurnal dynamics of plant element concentrations were regular and species-specific.     

Nutritional interactions in intestinal cadmium uptake - Possibilities for risk reduction

Effects of dietary composition and trace element status on fractional intestinal cadmium uptake is reviewed below. Fractional cadmium uptake is of fundamental importance for internal dose, related individual susceptibility to cadmium, induced renal damage and eventually bone disease. Diet composition with regard to macronutrients has some effects on cadmium bioavailability. Major determinants of intestinal cadmium uptake are however diet composition with regard to crude fibres and trace elements, especially iron. Deficiencies may increase intestinal cadmium uptake 5-8 times. Ultimate risk management would be not to raise crops on cadmium polluted soil. Provisionally, assurance of optimal trace element statusin persons exposed to cadmium is essential for risk reduction.     

Trace elements in the atmosphere.

The distribution and behaviour of particulate trace elements in the atmosphere have been studied by continuous measurements for 5 years at seven non-urban sites in the United Kingdom. Samples have been taken regularly of airborne dust, rainwater and dry deposition: these have been analysed for up to 36 elements. Concentrations of trace elements vary considerably between sites but the relative concentrations are among uniform: this suggests similarity of origin or good atmospheric mixing. By comparing the relative concentrations with those in soil it is possible to differentiate between trace elements that are derived from soil and those that may be attributed to industrial activity. This classification is supported by estimates of the particle sizes in air. The deposition of trace elements can be related to the concentrations presnet in soil and to the annual removal by crops. Retrospective analyses of stored samples from one site describe the history of trace element concentrations in air since 1957. The sea surface is considered as a possible source of atmospheric trace elements.     

Trace elements in man.

It is likely that most, if not all, of the elements found to be essential in animals will be shown to be so for man, and the clinical picture produced by deficiency of the elements in the human patient will differ little from that seen in the animal, although this has been established for only five elements (I, Fe, Cu, Co and Zn). However, the link between lack of a given element in the soil and a human patient is far less direct and much more complex than that met with in the animal grazing on deficient pastures, except in isolated primitive communitis. Zn is the most protean of the trace elements and has been chosen to illustrate this in human practice. Excesses of essential elements (both trace and major) give rise to toxic effects and the importance of a proper balance especially of the transitional elements in the human diet is discussed with special reference to Cu, Zn and Fe. Certain non-essential trace elements are individual and community hazards: Cd, Pb and Hg are the principal offenders for humans. Mankind is now largely dependent on grassland products, cereals and livestock with increasing dominance of the former in human nutrition. This has reduced the bioavailability of trace elements so that study of trace metals, especially Zn and Cu, in skeletal and dental remains at human burial and occupation sites should prove useful in assessing the consequences of this striking change in dietary habits.     

Dietary intake and bioavailability of trace elements

In order to assess the nutritional importance of trace elements, it is relevant to consider the factors regulating their metabolism. One of the most important factors is the true intake level. Conventional techniques such as diet history and interview studies in conjunction with standard food tables do not provide the true intake levels from prepared meals. Employing the duplicate portion technique, we have investigated the dietary intake of trace elements in prepared meals consumed by children, adults, and elderly in Sweden. The results indicate that the intake of potassium, magnesium, zinc, copper, and selenium is low when compared with the present recommended dietary allowance (RDA) values. It appears that a marginal deficiency of a number of trace elements may exist in the general population of affluent countries. When the dietary intakes are known, it is necessary to consider the bioavailability. This depends on the chemical form as well as the concentration of other dietary constituents such as fiber, phytate, carbohydrates, macrominerals, and vitamins in the diet. Knowledge of these interactions are important to improve the overall nutritional status of the population in general and patients in particuler.     

Measurement of trace elements in murine liver tissue samples: Comparison between ICP-MS/MS and TXRF

BackgroundTrace elements exhibit essential functions in many physiological processes. Thus, for research focusing on trace element homeostasis and metabolism analytical methods allowing for multi-element analyses are fundamental. Small sample amounts may be a big challenge in trace element analyses especially if also other end points want to be addressed in the same sample. Therefore, the aim of the present study was to examine trace elements (iron, copper, zinc, and selenium) in murine liver tissue prepared by a RIPA buffer-based lyses method.Methods and resultsAfter centrifugation, lysates and pellets were obtained and trace elements were analyzed with TXRF in liver lysates. The results were compared to that obtained by a standard microwave-assisted acidic digestion with subsequent ICP-MS/MS analysis of the same liver tissue, liver lysates, and remaining pellets. In addition, trace element concentrations, determined in murine serum with both methods, were compared. For serum samples, both TXRF and ICP-MS/MS provide similar and highly correlating results. Furthermore, in liver lysate samples prepared with RIPA buffer, comparable trace element concentrations were measured by TXRF as with the standard digestion technique and ICP-MS/MS. Only marginal amounts of trace elements were detected in the pellets.ConclusionTaken together, the results obtained by the present study indicate that the RIPA buffer-based method is suitable for sample preparation for trace element analyses via TXRF, at least for the here investigated murine liver samples.     

The uptake of trace elements by spinach and bean varieties of different root parameters

The uptake by plants of trace elements from the soil depends to a large extent on root characteristics and activities. Differences between plant species and varieties in the uptake of trace elements are well known. Less understood, however, are the mechanisms governing these differences and the relative significance of various root parameters.Spinach and bean varieties were, therefore, compared with respect to their root lengths and number of root apices, and to the uptake of Mn, Fe and Zn from soil-sand mixtures. The results showed significant differences among the varieties tested, both in root characteristics and in the uptake of trace elements. However, no relationships were evident between the trace element uptake by spinach varieties and their root characteristics. Contrary to this the Fe-uptake by bean varieies exhibited a clear dependence on the total number of root apices. The uptake of Mn and Zn showed a similar relationship with some exceptions. Whether the apical regions of individual roots are the most active sites of uptake or rather affect the solubility of trace elements will be the subject of further investigations.     

Effects of storage conditions on the stability and distribution of clinical trace elements in whole blood and plasma: Application of ICP-MS

BackgroundKnowledge of trace element stability during sample handling and preservation is a prerequisite to produce reliable test results in clinical trace element analysis.MethodAn alkaline dissolution method has been developed using inductively coupled plasma mass spectrometry to quantify eighteen trace element concentrations: vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, bromine, molybdenum, cadmium, antimony, iodine, mercury, thallium, lead, and bismuth in human blood, using a small sample volume of 0.1 mL. The study evaluated the comparative effects of storage conditions on the stability of nutritionally essential and non-essential elements in human blood and plasma samples stored at three different temperatures (4 °C, −20 °C and −80 °C) over a one-year period, and analysed at multiple time points. The distribution of these elements between whole blood and plasma and their distribution relationships are illustrated using blood samples from 66 adult donors in Queensland.ResultsThe refrigeration and freezing of blood and plasma specimens proved to be suitable storage conditions for many of the trace elements for periods up to six months, with essentially unchanged concentrations. Substantially consistent recoveries were obtained by preserving specimens at −20 °C for up to one year. Ultra-freezing of the specimens at −80 °C did not improve stability; but appeared to result in adsorption and/or precipitation of some elements, accompanied by a longer sample thawing time. A population sample study revealed significant differences between the blood and plasma concentrations of six essential elements and their relationships also varied significantly for different elements.ConclusionBlood and plasma specimens can be reliably stored at 4 °C for six months or kept frozen at −20 °C up to one year to obtain high quality test results of trace elements.     

Fermentation of food and feed: A technology for efficient utilization of macro and trace elements in monogastrics

Mineral deficiencies, especially of iron, zinc, and calcium, respectively, negatively affect human health and may lead to conditions such as iron deficiency anemia, rickets, osteoporosis, and diseases of the immune system. Cereal grains and legumes are of global importance in nutrition of monogastrics (humans and the respective domestic animals) and provide high amounts of several minerals, e.g., iron, zinc, and calcium. Nevertheless, their bioavailability is low. Plants contain phytates, the salts of phytic acid, chemically known as inositol-hexakisphosphate, which interact with several minerals and proteins. However, phytate may be hydrolysed by phytase. This enzyme is naturally present in plants and also widely distributed in microorganisms. Several food processing methods have been reported to enhance phytate hydrolysis, due to the activation of endogenous phytase activity or via the enzyme produced by microbes. In recent years, fermentation for food and feed improvement and preservation, respectively, has gained increasing interest as a promising method to degrade phytate and enhance mineral utilization in monogastrics. Indeed, several in vitro as well as in vivo studies confirm a positive effect on the utilization of minerals, such as P, Ca, Fe and Zn, using sourdough fermentation for baking or fermentation of legumes, mainly soybeans. This review summarizes the current knowledge regarding the potential of fermentation to enhance macro and trace element bioavailability in monogastric species.     

Trace elements in soils and crops.

To demonstrate the total amounts to be expected in soils, the ranges of contents of some 60 trace elements in ten representative Scottish arable surface soils are compared with ranges in soil-forming rocks and with crustal averages. It is, however, the amounts potentially available to plants rather than the total contents that are biologically significant. In temperate climates, trace element mobilization is greatest when weathering takes place under conditions of impeded pedological drainage, leading to the formation of gleyed soils. Mobilized trace elements occur in arable surface soils largely in adsorbed and chelated forms, which are available to plants to a greater or smaller extent depending on the prevailing soil parameters and on the element in question. Different species take up different amounts of trace elements: the proportions in the various plant parts vary with the element and the stage of growth. Information is required about the mobilization and uptake of many elements about which little is at present known but which may affect the functions of essential elements through inter-element interactions. Systematic soil surveys in which soils are mapped by associations related to parent material, with their series related to genetic soil types, provide a useful countrywide guide to trace element status.     

Bioavailability of Trace Elements in Beans and Zinc-Biofortified Wheat in Pigs

The objectives of this experiment were to study bioavailability of trace elements in beans and wheat containing different levels of zinc and to study how the water solubility of trace elements was related to the bioavailability in pigs. Three wheat and two bean types were used: wheat of Danish origin as a control (CtrlW), two Turkish wheat types low (LZnW) and high (HZnW) in zinc, a common bean (Com), and a faba bean (Faba). Two diets were composed by combining 81?% CtrlW and 19?% Com or Faba beans. Solubility was measured as the trace element concentration in the supernatant of feedstuffs, and diets incubated in distilled water at pH?4 and 38°C for 3?h. The bioavailability of zinc and copper of the three wheat types and the two bean-containing diets were evaluated in the pigs by collection of urine and feces for 7?days. The solubility of zinc was 34?C63?%, copper 18?C42?%, and iron 3?C11?%. The zinc apparent digestibility in pigs was similar in the three wheat groups (11?C14?%), but was significantly higher in the CtrlW+Faba group (23?%) and negative in the CtrlW+Com group (?30?%). The apparent digestibility of copper was higher in the HZnW (27?%) and CtrlW+Faba (33?%) groups than in the CtrlW (17?%) and LZnW (18?%) groups. The apparent copper digestibility of the CtrlW+Com diet was negative (?7?%). The solubility and digestibility results did not reflect the concentration in feedstuffs. The in vitro results of water solubility showed no relationship to the results of trace mineral bioavailability in pigs.