Dietary phytate × calcium/zinc millimolar ratios and zinc nutriture in some Ontario preschool children

Millimolar ratios of phytate/Zn, Ca x phytate/Zn, and Ca x phytate/Zn per 4.2 MJ were calculated from 3-d weighed-food records collected from 62 male (M) (mean age: 58 +/- 7 mo [mean +/- SD]) and 44 female (F) (mean age: 58 +/- 6 mo) preschool children from Southern Ontario. Food-composition values for phytate were based on laboratory analysis and the literature. No gender differences existed for median millimolar ratios of phytate/Zn (median: M, 5.3; F, 5.3), and Ca x phytate/Zn per 4.2 MJ (M, 68.1; F, 59.5), but median intakes of phytate (M, 399; F, 333 mg/d) and median millimolar ratios of Ca x phytate/Zn (median: M, 102.1; F, 72.3; p less than 0.01) were higher for boys than for girls. Of the children, only two (1M, 1F) and 22 (17 M, 5F) had millimolar ratios of phytate/Zn and Ca x phytate/Zn per 4.2 MJ, respectively, that were above critical values. Millimolar ratios of Ca x phytate/Zn (p = 0.06) and Ca x phytate/Zn per 4.2 MJ (p = 0.05) were higher in boys with hair zinc less than 1.07 mumol/g v greater than or equal to 1.07 mumol/g. Analysis of variance showed that height was influenced by an interaction between millimolar ratios of Ca x phytate/Zn per 4.2 MJ and sex (p = 0.0007), when age and midparent height were treated as covariates. Results suggest that dietary Ca x phytate/Zn millimolar ratios, when expressed per 4.2 MJ, influenced the zinc nutriture of these Southern Ontario boys.     

Zinc inhibition of electron transfer: mechanism of beta receptor inhibition?

Zinc has been shown to inhibit β-receptor activation of adenylate cyclase at a post receptor site. We have postulated that the β-receptor is one of several receptors activated by reduction, followed by transmembrane elector transfer accelerated by GTP. GTP accelerates electron transfer in a model system and this accelerated electron transfer is inhibited by zinc. This could explain the mechanism of the post receptor inhibition by zinc of the adenylate cyclase stimulation which follows β-receptor activation.     

Short communication. Carbon:nitrogen ratios of Baltic Sea copepods-indication of mineral limitation?

The carbon (C) and nitrogen (N) content and the C:N ratio of two common calanoid copepods, Eurytemora affinis and Acartia bifilosa were measured during spring and summer at the SW coast of Finland, northern Baltic Sea. The C:N ratio of both copepod species was slow and stable (4-4.5), irrespective of sampling time, which implies N limitation at least during intermediate to high food concentrations in spring and early summer. In addition, experiments were conducted to reveal whether the diet of copepods affects their C and N content. Adding green algae Brachiomonas submarina in concentrations of 50-500 g C l^-1 to <100-m-filtered sea water did not significantly increase copepod C or N content in 3 day experiments. However, the C and N contents of E.affinis eggs were 2 times higher in high food concentration, which may increase survival of eggs and nauplii.      

Otolith Sr : Ca ratios of the freshwater and anadromous cyprinid genus Tribolodon

The ratio of strontium to calcium concentration in the otolith of four species of Tribolodon (Cyprinidae) was examined to reveal their migratory histories. The ratio was relatively stable from the core to the edge of the otolith in fluvial Tribolodon ezoe and T. hakonensis, whereas it changed from a low level to a higher level in anadromous T. brandtii and T. hakonensis. Four specimens of T. nakamurai from the Mogami River, Yamagata Prefecture, northern Japan, showed relatively stable ratios, indicating a fluvial life mode. On the other hand, the ratio increased once in only one specimen of T. nakamurai from the Koyoshi River of Akita Prefecture, suggesting the possibility that it was born in the Mogami River, the nearest major habitat of this species, and accidentally migrated to the Koyoshi River through the sea.     

Pattern and variation of C:N:P ratios in China’s soils: a synthesis of observational data

Inspired by previous studies that have indicated consistent or even well-constrained (relatively low variability) relations among carbon (C), nitrogen (N) and phosphorus (P) in soils, we have endeavored to explore general soil C:N:P ratios in China on a national scale, as well as the changing patterns of these ratios with soil depth, developmental stages and climate; we also attempted to determine if well-constrained C:N:P stoichiometrical ratios exist in China’s soil. Based on an inventory data set of 2,384 soil profiles, our analysis indicated that the mean C:N, C:P and N:P ratios for the entire soil depth (as deep as 250 cm for some soil profiles) in China were 11.9, 61 and 5.2, respectively, showing a C:N:P ratio of ~60:5:1. C:N ratios showed relatively small variation among different climatic zones, soil orders, soil depth and weathering stages, while C:P and N:P ratios showed a high spatial heterogeneity and large variations in different climatic zones, soil orders, soil depth and weathering stages. No well-constrained C:N:P ratios were found for the entire soil depth in China. However, for the 0–10 cm organic-rich soil, which has the most active organism–environment interaction, we found a well-constrained C:N ratio (14.4, molar ratio) and relatively consistent C:P (136) and N:P (9.3) ratios, with a general C:N:P ratio of 134:9:1. Finally, we suggested that soil C:N, C:P and N:P ratios in organic-rich topsoil could be a good indicator of soil nutrient status during soil development.     

Degradation of phytate in the gut of pigs ‐ pathway of gastrointestinal inositol phosphate hydrolysis and enzymes involved

The present study gives an overview on the whole mechanism of phytate degradation in the gut and the enzymes involved. Based on the similarity of the human and pigs gut, the study was carried out in pigs as model for humans. To differentiate between intrinsic feed phytases and endogenous phytases hydrolysing phytate in the gut, two diets, one high (control diet) and the other one very low in intrinsic feed phytases (phytase inactivated diet) were applied. In the chyme of stomach, small intestine and colon inositol phosphate isomers and activities of phytases and alkaline phosphatases were determined. In parallel total tract phytate degradation and apparent phosphorus digestibility were assessed. In the stomach chyme of pigs fed the control diet, comparable high phytase activity and strong phytate degradation were observed. The predominant phytate hydrolysis products were inositol phosphates, typically formed by plant phytases. For the phytase inactivated diet, comparable very low phytase activity and almost no phytate degradation in the stomach were determined. In the small intestine and colon, high activity of alkaline phosphatases and low activity of phytases were observed, irrespective of the diet fed. In the colon, stronger phytate degradation for the phytase inactivated diet than for the control diet was detected. Phytate degradation throughout the whole gut was nearly complete and very similar for both diets while the apparent availability of total phosphorus was significantly higher for the pigs fed the control diet than the phytase inactivated diet. The pathway of inositol phosphate hydrolysis in the gut has been elucidated.     

Role of Zinc in Zinc-α2-Glycoprotein Metabolism in Obesity: a Review of Literature

Biological Trace Element Research - Excessive adipose tissue promotes the manifestation of endocrine disorders such as reduction of the secretion of zinc-α2-glycoprotein (ZAG), an adipokine...     

Adsorption of α-amylase and Starch on Porous Zinc Oxide Nanosheet: Biophysical Study

Food Biophysics - Engineered biocatalyst and its desired products using nanotechnology has intensified the research in food industries. Zinc oxide (ZnO) nanosheet is designed and prepared; the...     

Copper and Zinc Mediated Oligomerisation of Aβ Peptides

The accumulation of senile plaques composed primarily of aggregated amyloid β-peptide (Aβ), is the major characteristic of Alzheimer’s disease. Many studies correlate plaque accumulation and the presence of metal ions, particularly copper and zinc. The metal binding sites of the amyloid Aβ peptide of Alzheimer’s disease are located in the N-terminal region of the full-length peptide. In this work, the interactions with metals of a model peptide comprising the first 16 amino acid residues of the amyloid Aβ peptide, Aβ(1–16), were studied. The effect of Cu²⁺ and Zn²⁺ binding to Aβ(1–16) on peptide structure and oligomerisation are reported. The results of ESI-MS, gel filtration chromatography and NMR spectroscopy demonstrated formation of oligomeric complexes of the peptide in the presence of the metal ions and revealed the stoichiometry of Cu²⁺ and Zn²⁺ binding to Aβ(1–16), with Cu²⁺ showing a higher affinity for binding the peptide than Zn²⁺.     

Identifying sea-run brown trout, Salmo trutta, using Sr : Ca ratios of otolith

 The migratory history of the brown trout, Salmo trutta, collected from Japanese rivers, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith, by means of wavelength dispersive X-ray spectrometry on an electron microprobe. Sea-run (anadromous) and freshwater-resident (nonanadromous) types of S. trutta were found to occur sympatrically. Otolith Sr concentration or Sr : Ca ratios of anadromous S. trutta fluctuated strongly along the life history transect in accordance with the migration (habitat) pattern from sea to freshwater. In contrast, the Sr concentration or the Sr : Ca ratios of nonanadromous fish remained at consistently low levels throughout the otolith. The higher ratios in anadromous S. trutta, in the otolith region from the core to 1500 μm, corresponded to the initial seagoing period, probably reflecting the ambient salinity or the seawater–freshwater gradient in Sr concentration. The findings clearly indicated that otolith Sr : Ca ratios reflected individual life histories, enabling the sea-run S. trutta to be distinguished from the freshwater-resident brown trout. Received: March 18, 2002 / Revised: May 15, 2002 / Accepted: June 5, 2002 Acknowledgments The authors are grateful to Messrs. T. Ikeda, S. Kudo, Y. Miyakoshi, M. Nagata, K. Shimoda, T. Takami, K. Takeuchi, and M. Ueda for their assistance in collecting specimens. This work was supported in part by Grant-in-Aid No. 13760138 from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Correspondence to:Takaomi Arai     

Influences of β-HCG administration on carbon isotope ratios of endogenous urinary steroids

Several factors influencing the carbon isotope ratios (CIR) of endogenous urinary steroids have been identified in recent years. One of these should be the metabolism of steroids inside the body involving numerous different enzymes. A detailed look at this metabolism taking into account differences found between steroids excreted as glucuronides or as sulphates and hydrogen isotope ratios of different steroids pointed out possibility of unequal CIR at the main production sites inside the male body - the testes and the adrenal glands. By administration of β-HCG it is possible to strongly stimulate the steroid production within the testes without influencing the production at the adrenal glands. Therefore, this treatment should result in changed CIR of urinary androgens in contrast to the undisturbed pre-treatment values. Four male volunteers received three injections of β-HCG over a time course of 5 days and collected their urine samples at defined intervals after the last administration. Those samples showing the largest response in contrast to the pre-administration urines were identified by steroid profile measurements and subsequent analysed by GC/C/IRMS. CIR of androsterone, etiocholanolone, testosterone, 5α- and 5β-androstanediol and pregnanediol were compared. While pregnanediol was not influenced, most of the investigated androgens showed depleted values after treatment. The majority of differences were found to be statistically significant and nearly all showed the expected trend towards more depleted δ(13)C-values. These results support the hypothesis of different CIR at different production sites inside the human body. The impact of these findings on doping control analysis will be discussed.     

Zinc Suppressed the Airway Inflammation in Asthmatic Rats: Effects of Zinc on Generation of Eotaxin, MCP-1, IL-8, IL-4, and IFN-γ

Airway epithelium is rich in labile zinc (Zn), which may have an important protective role in the airway epithelium. The aim of this study is to investigate the effects of Zn on the airway inflammation and the generation of eotaxin, monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), interleukin-4 (IL-4), and interferon-?? (IFN-??) in rat models of ovalbumin (OVA)-induced allergic airway inflammation. For this purpose, animal model of asthma was established by OVA challenge and zinc-deficient and zinc-supplemented diets were given. Thirty-two Sprague?CDawley rats were divided into four groups: zinc-deficient diet with OVA treatment group, zinc-supplemented diet with OVA treatment group, zinc-normal diet with OVA treatment group, and zinc-normal diet with saline treatment group. Twenty-four hours after asthma was induced, lung histomorphological changes, cells in bronchoalveolar lavage fluid (BALF), contents of eotaxin, MCP-1, and IL-8 in BALF, and the expression of IFN-?? and IL-4 mRNAs were observed. Compared with the group of zinc-normal diet with OVA challenge rats, the group of zinc-deficient rats had higher numbers of eosinophils, neutrophils, and monocytes in BALF, as well as higher contents of eotaxin and MCP-1 in BALF and lower expression of lung IFN-?? mRNA. Conversely, Zn supplementation would decrease the numbers of eosinophils, neutrophils, and monocytes in BALF; suppress eotaxin and MCP-1 protein secretion; and increase lung IFN-?? mRNA expression. No significant difference was observed in IL-8 and IL-4 among OVA-challenged rats with different zinc diets. These studies suggested that Zn may be an important anti-inflammatory mediator of airway inflammation.     

Association Between Serum Zinc Levels and the Risk of Parkinson’s Disease: a Meta-Analysis

Recent studies have found that the serum zinc levels were associated with the risk of Parkinson’s disease (PD), but the results were inconsistent. Thus, we conducted a meta-analysis to summarize the evidence from observational studies between them. Pertinent studies were identified by a search in PubMed, Embase, and Web of science up to July, 10, 2016. Standardized mean difference (SMD) and 95% confidence intervals (CI) with random-effect model was used to combine the results. Subgroup analysis and meta-regression were also conducted. Publication bias was estimated using Begg’s regression asymmetry test. A total of 11 articles involving 822 PD patients and 777 healthy controls were included in the meta-analysis. Our meta-analysis results revealed that the serum zinc levels in PD patients were significantly lower than those in health controls (SMD = ?0.779, 95%CI = [?1.323, ?0.234], P < 0.001). The association was also significant oriental studies (SMD = ?1.601, 95%CI = [?2.398, ?0.805], P < 0.001). No publication bias was found. The current study indicated that serum zinc levels in PD patients were significantly lower than those in healthy controls.     

Are the ratios of bill crossing morphs in crossbills the result of frequency-dependent selection?

Summary The direction the lower mandible curves in crossbills (Loxia) is an example of a discrete polymorphism. The lower mandible crosses with equal frequency to the left and to the right in several crossbill populations. I hypothesize that the 1:1 ratio results from negative frequency-dependent selection favouring the rarer morph. A crossbill always orients toward closed conifer cones so that its lower mandible is directed towards the cone axis. Thus, only part of the cone can be reached easily when crossbills have few perch sites and the cone cannot be removed from the branch or otherwise turned round. Since crossbills may visit cones which have previously been foraged on by other individuals, an equal frequency of left-to-right mandible crossings may minimize overlap in the use of cones and enhance foraging efficiency. Experimental data support this hypothesis. Moreover, the variation in the ratio of mandible crossing directions among crossbill populations is consistent with this hypothesis.     

Zinc and diabetes mellitus: is there a need of zinc supplementation in diabetes mellitus patients?

Diabetes mellitus is a group of metabolic disorders, the incidence of which varies widely throughout the world. The treatment of diabetes mellitus includes insulin, oral antidiabetic agents, and dietary regimens. Although the emphasis is on macronutrients intakes, there is strong evidence that there is an abnormal metabolism of several micronutrients in diabetic individuals. Zinc is one of the essential micronutrients of which status and metabolism is altered in this condition. This work is a short review about the close relation among zinc, glucose metabolism, and insulin physiology, as well as about the few experimental data about zinc absorption and zinc supplementation in diabetes mellitus patients.     

Structural basis for increased toxicity of pathological aβ42:aβ40 ratios in Alzheimer disease

The β-amyloid peptide (Aβ) is directly related to neurotoxicity in Alzheimer disease (AD). The two most abundant alloforms of the peptide co-exist under normal physiological conditions in the brain in an Aβ(42):Aβ(40) ratio of ～1:9. This ratio is often shifted to a higher percentage of Aβ(42) in brains of patients with familial AD and this has recently been shown to lead to increased synaptotoxicity. The molecular basis for this phenomenon is unclear. Although the aggregation characteristics of Aβ(40) and Aβ(42) individually are well established, little is known about the properties of mixtures. We have explored the biophysical and structural properties of physiologically relevant Aβ(42):Aβ(40) ratios by several techniques. We show that Aβ(40) and Aβ(42) directly interact as well as modify the behavior of the other. The structures of monomeric and fibrillar assemblies formed from Aβ(40) and Aβ(42) mixtures do not differ from those formed from either of these peptides alone. Instead, the co-assembly of Aβ(40) and Aβ(42) influences the aggregation kinetics by altering the pattern of oligomer formation as evidenced by a unique combination of solution nuclear magnetic resonance spectroscopy, high molecular weight mass spectrometry, and cross-seeding experiments. We relate these observations to the observed enhanced toxicity of relevant ratios of Aβ(42):Aβ(40) in synaptotoxicity assays and in AD patients.     

Zinc depletion regulates the processing and secretion of IL-1β

Sterile inflammation contributes to many common and serious human diseases. The pro-inflammatory cytokine interleukin-1β (IL-1β) drives sterile inflammatory responses and is thus a very attractive therapeutic target. Activation of IL-1β in sterile diseases commonly requires an intracellular multi-protein complex called the NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome. A number of disease-associated danger molecules are known to activate the NLRP3 inflammasome. We show here that depletion of zinc from macrophages, a paradigm for zinc deficiency, also activates the NLRP3 inflammasome and induces IL-1β secretion. Our data suggest that zinc depletion damages the integrity of lysosomes and that this event is important for NLRP3 activation. These data provide new mechanistic insight to how zinc deficiency contributes to inflammation and further unravel the mechanisms of NLRP3 inflammasome activation.     

Three-dimensional finite element analysis of stress distribution in retention screws of different crown–implant ratios

The retaining screw of the implant-supported dental prosthesis is the weakest point of the crown/implant system. Furthermore, crown height is another important factor that may increase the lever arm. Therefore, the aim of this study was to assess the stress distribution in implant prosthetic screws with different heights of the clinical crown of the prosthesis using the method of three-dimensional finite element analysis. Three models were created with implants (3.75 mm × 10 mm) and crowns (heights of 10, 12.5 and 15 mm). The results were visualised by means of von Mises stress maps that increased the crown heights. The screw structure exhibited higher levels of stresses in the oblique load. The oblique loading resulted in higher stress concentration when compared with the axial loading. It is concluded that the increase of the crown was damaging to the stress distribution on the screw, mainly in oblique loading.     

Zinc Protoporphyrin Suppresses β-Catenin Protein Expression in Human Cancer Cells: The Potential Involvement of Lysosome-Mediated Degradation

Zinc protoporphyrin (ZnPP) has been found to have anticancer activity both in vitro and in vivo. We have recently demonstrated that ZnPP diminishes β-catenin protein expression in cancer cells. The present study examined the cellular mechanisms that mediate ZnPP’s suppression of β-catenin expression. We demonstrate that ZnPP induces a rapid degradation of the β-catenin protein in cancer cells, which is accompanied by a significant inhibition of proteasome activity, suggesting that proteasome degradation does not directly account for the suppression. The possibility that ZnPP induces β-catenin exportation was rejected by the observation that there was no detectable β-catenin protein in the conditioned medium after ZnPP treatment of cancer cells. Further experimentation demonstrated that ZnPP induces lysosome membrane permeabilization, which was reversed by pretreatment with a protein transportation inhibitor cocktail containing Brefeldin A (BFA) and Monensin. More significantly, pretreatment of cancer cells with BFA and Monensin attenuated the ZnPP-induced suppression of β-catenin expression in a concentration- and time-dependent manner, indicating that the lysosome protein degradation pathway is likely involved in the ZnPP-induced suppression of β-catenin expression. Whether there is cross-talk between the ubiquitin-proteasome system and the lysosome pathway that may account for ZnPP-induced β-catenin protein degradation is currently unknown. These findings provide a novel mechanism of ZnPP’s anticancer action and reveal a potential new strategy for targeting the β-catenin Wnt signaling pathway for cancer therapy.