Root exudation and Fe uptake and transport in wheat genotypes differing in tolerance to Zn deficiency

Tolerance to Zn deficiency in wheat germplasm may be inversely related to uptake and transport of Fe to shoots. The present study examined eight bread (Triticum aestivum) and two durum (T. turgidum L. conv. durum) wheat genotypes for their capacity to take up and transport Fe when grown under either Fe or Zn deficiency. Bread wheat genotypes Aroona, Excalibur and Stilleto showed tolerance to Zn and Fe deficiency, while durum wheat genotypes are clearly less tolerant to either deficiency. Roots of bread wheats tolerant to Zn deficiency exuded more phytosiderophores than sensitive bread and durum genotypes. Greater amounts of phytosideophores were exuded by roots grown under Fe than Zn deficiency. A relatively poor relationship existed between phytosiderophore exudation or the Fe uptake rate and relative shoot growth under Fe deficiency. At advanced stages of Zn deficiency, genotypes tolerant to Zn deficiency (Aroona and Stilleto) had a greater rate of Fe uptake than other genotypes. Zinc deficiency depressed the rate of Fe transport to shoots in all genotypes in early stages, while advanced Zn deficiency had the opposite effect. Compared with Zn-sufficient plants, 17-day-old Zn-deficient plants of genotypes tolerant to Zn deficiency had a lower rate of Fe transport to shoots, while genotypes sensitive to Zn deficiency (Durati, Yallaroi) had the Fe transport rate increased by Zn deficiency. A proportion of total amount of Fe taken up that was transported to shoots increased with duration of either Fe or Zn deficiency. It is concluded that greater tolerance to Zn deficiency among wheat genotypes is associated with the increased exudation of phytosiderophores, an increased Fe uptake rate and decreased transport of Fe to shoots. This revised version was published online in June 2006 with corrections to the Cover Date.     

Interrelations between ceruloplasmin and Fe status during human pregnancy

It is well established that Fe and ceruloplasmin interact in animals and in in vitro models. However, Fe-mediated regulation of ceruloplasmin has never been investigated in humans. In an observational study, 53 pregnant women aged 19–39 yr (29.8±0.7 yr, mean ± SEM) were recruited at the Aberdeen Antenatal Clinic, Aberdeen Maternity Hospital, UK. All requirements for local ethical committees were followed. Venous blood samples were taken from each woman at 34 wk gestation for measurement of Fe status and ceruloplasmin. Various parameters were used to test for Fe status. The most sensitive one appeared to be soluble transferrin receptor, which increased with parity. In the population studied, there was no relationship between hemoglobin or ferritin and serum ceruloplasmin. However, using soluble transferrin receptor (sTfR) levels, we were able to demonstrate an inverse linear relationship (r=0.37, p=0.021, n=41) between Fe status and ceruloplasmin. Fe supplementation, number of previous pregnancies, and smoking habits did not affect this relationship. Our data support in vitro results showing regulation of ceruloplasmin by Fe and also suggest that the interactions between Fe and ceruloplasmin should be considered when Fe supplementation is given.     

血虚证的现代研究概述

很多学者从血虚证的发病原因、病理、动物模型制作及传统方药等方面在整体、细胞、分子等水平上对血虚证作了深入地研究,在血虚病理变化、动物模型制作及四物汤、当归补血汤等相关方药研究上取得了一定的共识。血虚时,机体造血功能抑制,免疫功能降低,红细胞膜的酶如Na~ 、K~ -ATP酶活性降低,水盐代谢紊乱及细胞内一些信使物质含量异常等。通过放血、化学损伤、放射线损伤等造成血虚证的动物实验研究,人们进一步发现了传统方药对血虚证的治疗作用机制。这些经典方药都能增强机体免疫,促进造血干祖细胞的增殖分化,促进血细胞的生成从而发挥补血作用。这些研究大大丰富和发展了传统的中医血虚理论,为疾病的预防、诊断、治疗、预后判断提供了更客观、更全面的指导。     

Health risk to children exposed to Zn,Pb, and Fe in selected urban parks of the Silesian agglomeration

In selected urban parks of the Silesian agglomeration, samples of soil, sand and dust were collected and analyzed for Zn, Pb and Fe contents.The highest soil concentrations of the metals were found in park no. I (Ko?ciuszki) in Katowice (average concentrations 244, 341 and 9375 mg/kg, respectively) and slightly lower soil concentrations were found in the park no. III (Silesian) in Chorzów (131, 211 and 9017 mg/kg, respectively). Lower contents of Zn (average 38 mg/kg) as well as Pb (71 mg/kg) and Fe (3226 mg/kg) characterize the soils of park no. II in Katowice. Concentrations of the metals in sands are on average, significantly lower, equivalent to two to three times, than those of the soil samples. The contents of metals in dusts are more variable than in soils and sands. While comparing the amount of Pb in the dust to their concentration in soils, it must be noted that for the majority of the samples they are lower. They account for 76% of the total concentration in the soil. The calculated quotient hazards of health clearly indicate a potential health risk caused by Pb, especially for young children due to their low weight. The highest health risk was established for park no. I, slightly lower for park no. III and the lowest for park no. II.     

Correlation of iron content, spectral forms of chlorophyll and chlorophyll-proteins in iron deficient cucumber (Cucumis sativus)

Leaves and chloroplast suspensions of severely and slightly iron deficient cucumber ( Cucumis sativus L.) plants were characterized by low-temperature fluorescence emission spectroscopy and Deriphat polyacrylamide gel electrophoresis. The emission spectra of the chloroplast suspensions were resolved into Gaussian components and those changes induced by iron deficiency were related to the variations in the chlorophyll-protein pattern. The symptoms described with these methods were also correlated with the iron content of the leaves. It was concluded that the lack of physiologically active iron caused a relative decrease of photosystem I (PSI) and light harvesting complex I (LHCI), together with the long wavelength fluorescence, especially the 740 nm Gaussian component, and. to a much lesser extent, of the photosystem II (PSII) core complexes (relative increase of 685, 695 nm components). However, the relative decrease in the amount of light harvesting complex II (LHCII) was followed by a relative increase in its fluorescence band at 680 nm, showing that energy transfer from LHCII to core complex II (CCII) was partly disturbed. Thus iron deficiency affected the photosynthetic apparatus in a complex way: it decreased the synthesis of chlorophylls (Chls) and influenced the expression and assembly of Chl-binding proteins.     

Micronutrient deficiency and the prevalence of mothers’ overweight/obesity in Egypt

I examine the relationship between micronutrient deficiency and the prevalence of mothers’ overweight/obesity in Egypt using the 1997 Egyptian Integrated Household Survey. The ordered logit results show an overlap between micronutrient deficiency and the prevalence of mothers’ overweight/obesity in Egypt. The odds of being overweight/obese are 80.8% higher for micronutrient deficient mothers than for non-deficient mothers, keeping all other variables constant. These results have at least two interesting policy implications. First, as the potential impact of the interaction between micronutrient deficiency and chronic diseases is not well known, the coexistence of micronutrient deficient and overweight/obese women can raise new and serious public health problems in the country. Second, the Egyptian food subsidy program, which lowers the relative prices of energy-dense, nutrient-poor food items, can be one of the major factors for the emergence of overweight/obese and micronutrient deficient mothers in the country. Changing the orientation of the food subsidy program may help to simultaneously address this double burden of mothers’ malnutrition.     

Viruses, cancer and AIDS

Patients with AIDS are at risk of lymphoma and Kaposi's sarcoma. These tumours are associated with the gamma herpesviruses, Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV-8), although a proportion of AIDS lymphomas lacks both viruses. EBV and HHV-8 are latent in the tumour cells, with genes that play a direct role in driving cell proliferation. Human immunodeficiency virus, in contrast, while being the greatest risk factor for lymphoma and Kaposi's sarcoma, acts indirectly, mainly by causing immune suppression, as immunosuppressed transplant patients are at risk for the same types of tumour.     

Enhancement by gonyautoxin V of the iron(III) reducing or binding activity produced by the dinoflagellate, Alexandrium excavatum

Reduction or binding of Fe(III) by agent(s) produced by a highly toxigenic strain of Alexandrium excavatum was detected at approximately the same levels in culture filtrates of this dinoflagellate grown either axenically or non-axenically. Nanomolar concentrations of pure Paralytic Shellfish Poisons (PSP) produced by this phytoplankton, the carbamate toxins saxitoxin, 2/3 gonyautoxin or the N-sulfamoyl carbamate toxins C1/C2, added to a Schwyn and Neilands (1987) assay mixture did not stimulate Fe(III) reduction or binding. In contrast, additions of the N-sulfamoyl carbamate toxin, gonyautoxin V (GTXV also known as B1) alone resulted in a several-fold increase in this activity. The level of activity per cell was considerably higher for those cultures grown in media deficient in iron than in those whose growth was restricted by decreases of either N or P.     

Combined effect of high-fat diet and copper deficiency during gestation on fetal copper status in the rat

We have previously shown that a low-copper (Cu) diet produced alterations in placental Cu transport and fetal Cu stores. Because Cu deficiency has been associated with lipid deposition in rat dam liver, we hypothesized that a high fat intake, a prevalent dietary habit in many populations, may worsen fetal Cu status and its closely linked iron (Fe) deposits. Pregnant rats were fed one of four diets during the second half of gestation: NFNCu: normal fat (7%), normal Cu (6 mg/kg); HFNCu: high fat (21%), normal Cu; NFLCu: normal fat, low Cu (0.6 mg/kg), and HFLCu: high fat, low Cu. One day before delivery, dams were anesthetized, and maternal as well as fetal plasma and tissues were obtained. Maternal, fetal, and placental weights were indistinguishable regardless of the group. Dam plasma Cu and placental Cu were lower in both LCu groups than in the NFNCu or the HFNCu groups. However, fetal plasma Cu was similar in all treatment groups. Dam and fetal liver Cu stores were reduced in the LCu groups compared to the NCu groups. This resulted in lower fetal/maternal liver Cu ratios in the NFLCu (1.79 ± 0.14,p < 0.05) and HFLCu (1.59 ± 0.21,p < 0.05) as compared to the NFNCu (4.12 ± 0.44) and the HFNCu (4.15 ± 0.27). Dam liver Fe was higher in the NFNCu than in HFNCu group (1.10 ± 0.8 vs. 0.89 ± 0.06 μmol/g,p < 0.05); fetal liver Fe from HFNCu and NFLCu dams was lower than that from NFNCu fetuses (NFNCu: 2.42 ± 0.14; HFNCu: 1.92 ± 0.15,p < 0.05; NFLCu: 1.81 ± 0.10,p < 0.01). Fetuses of the HFLCu group had a lower heart Fe than the NFNCu group (0.56 ± 0.03 vs. 44.0 ± 3.0 μg/g,p < 0.01). These data indicate that a maternal high-fat diet can potentially aggravate the effects of Cu deficiency by further altering fetal Cu and Fe tissue stores.     

Measurements in potassium-supplemented athletes during and after hypokinetic and ambulatory conditions

Hypokinesia (diminished movement) induces significant potassium (K) changes; however, little is known about K deposition and deficiency during hypokinesia (HK). Using K supplements during and after HK, the aim was to establish body K deposition and K deficiency during HK. Studies were done during the pre-HK period of 30 d, HK period of 364 d, and post-HK period of 30 d. Forty male trained athletes aged 24.9 ± 8.0 y were chosen as subjects. They were equally divided into four groups: unsupplemented active control subjects (UACS), unsupplemented hypokinetic subjects (UHKS), supplemented active control subjects (SACS), and supplemented hypokinetic subjects (SHKS). Hypokinetic subjects were limited to an average walking distance of 0.7 km/d. Control subjects ran an average distance of 11.6 km/d. The SHKS and SACS groups took 95.0 mg elemental K/kg body weight daily. Fecal K excretion, urinary sodium (Na) and K excretion, plasma K and Na levels, plasma renin activity (PRA), plasma aldosterone (PA), food and fluid intake, and physical characteristics were measured. During HK, fecal K loss, urinary K and Na loss, and plasma K, Na, PRA, and PA levels increased significantly (p ≤ 0.05), whereas during the initial days of post-HK, the levels of the measured parameters decreased significantly (p ≤ 0.05) in the SHKS and UHKS groups as compared with the SACS and UACS groups, respectively. During HK, body weight, body fat, peak oxygen uptake, food and fluid intake decreased significantly (p ≤ 0.05), whereas during the initial days of post-HK period remained significantly (p ≤ 0.05) depressed and fluid intake increased in SHKS and UHKS groups when compared with the SACS and UACS groups, respectively. However, during HK and post-HK plasma, urinary, and fecal K changed significantly (p ≤ 0.05) more in the SHKS group than in the UHKS group. The deposition of K was significantly (p ≤ 0.05) lower and K deficiency much higher in the SHKS group than in the UHKS group. Fecal K loss, urinary K and Na loss, plasma K, Na, PRA, and PA levels, body weight, body fat, peak oxygen uptake, and food and fluid intake did not change significantly in the SACS and UACS when compared with their baseline control values. It was shown that plasma K concentration and urinary and fecal K excretion increased during HK and decreased significantly (p ≤ 0.05) during post-HK. post-HK. Oral K supplements did not influence plasma or fecal and urinary K either during HK or post-HK. It was concluded that the low plasma K level and fecal and urinary K loss during post-HK may indicate the presence of K deficiency, and increased K in plasma, urine, and feces during HK and in the presence of K deficiency may suggest the body’s inability to retain K during HK.