Investigation of iron-containing products from natural and laboratory cultivated Sphaerotilus-Leptothrix bacteria.

Bacterial biomass collected from sheath-forming bacteria of the genera Sphaerotilus and Leptothrix was collected from a high-mountain natural stream water source. The elemental constitution and oxide phases of the products after selective cultivation of the bacteria on two different elective media using neutron activation analysis (NAA), electron microscopy (SEM, TEM), and X-ray diffraction (XRD) were studied. A high enrichment level of iron was revealed by the NAA technique in cultivated isolates as compared to the reference sample from nature. Three types of iron oxide compounds were established after cultivation in Adler's medium: lepidocrocite (γ-FeOOH), magnetite (Fe3O4), and goethite (α-FeOOH). The cultivation in the Isolation medium yielded a single phase, that of goethite, excluding one sample with a distinguishable amount of lepidocrocite. XRD and EM investigations show that the biogenic oxides are nanosized. Our study exemplifies the possibilities of the biotechnology approach for obtaining, under artificial conditions, large quantities of iron-containing by-products that could be of further used in appropriate nano- and biotechnologies.

Serum carotenoid and retinol levels during childhood infections.

BACKGROUND: In recent years, new physiological functions of vitamin A have been identified, including its role in immune defense. The antioxidant potential of carotenoids is thought to account for their health benefits. The aim of this study was to investigate the concentration changes in the provitamin-A (alpha- and-beta-carotene, beta-cryptoxanthin) and of the non-provitamin-A carotenoids (lutein, zeaxanthin and lycopene) in children with acute infections. METHODS: Serum retinol and carotenoid concentrations were measured by HPLC in 45 children suffering from acute infections and in 29 healthy controls. In addition 15 healthy children collected food samples over 2 days. C-reactive protein (CRP) levels were measured by turbidimetry. RESULTS: Serum levels of beta-carotene, alpha-carotene, beta-cryptoxanthin and retinol and non-provitamin-A carotenoid lutein and zeaxanthin concentrations were significantly lower in children with infections compared to healthy controls. There were significant negative correlations between CRP levels and serum beta-carotene and retinol concentrations. The average intake of retinol equivalents was 1.1 +/- 0.6 mg/day. CONCLUSION: Serum retinol and provitamin-A as well as non-provitamin-A carotenoid concentrations were lower in children with acute phase infections compared to healthy controls. The inverse correlations between CRP and beta-carotene or retinol indicate either decreased synthesis or increased utilization of these antioxidants.

Selenium and glutathione peroxidase activity in Hungarian children.

Selenium (Se) in plasma, whole blood and erythrocytes as well as glutathione peroxidase (GSH-Px) activity in plasma and erythrocytes were investigated in 161 healthy Hungarian children aged 1-15 years. Se was determined by AAS with hydride generation. The estimation of GSH-Px activity was performed in plasma with tertbutyl-hydroperoxide (t-BOOH) and in erythrocytes with hydrogen peroxide (H2O2) as acceptor substrates. The Se content in plasma (0.63 +/- 0.12 mumol/L), whole blood (0.81 +/- 0.14 mumol/L) and erythrocytes (1.14 +/- 0.26 mumol/L, the GSH-Px activity in plasma (87 +/- 19 U/L) and erythrocytes (5.93 +/- 1.04 U/gHb) was low in Hungarian children in comparison to values for children from other European countries. Samples from a rural area in southeast Hungary showed even lower Se content than samples from an industrial city in the northwest or from the capital. The Se in plasma and whole blood as well as GSH-Px activity in the plasma exhibited a clear age dependency. There was a good correlation between plasma Se and GSH-Px activity in all children (r = 0.633, p < 0.001). In addition, in children from the northwestern city and from the capital a correlation was found between Se content and GSH-Px activity of erythrocytes (r = 0.625, p < 0.001). There is no indication that the high mortality in young Hungarian adults from cardiovascular diseases is mainly caused by a low Se supply because there are no corresponding findings in the surrounding countries of southeastern or central eastern Europe with similar low Se states.

Selenium status and lipoproteins in healthy and diabetic children.

Selenium and the selenium-dependent glutathione peroxidase (GSH-Px) were measured in healthy and diabetic children from Germany and Hungary. Hyperglycemia and hyperlipidemia are present in diabetes mellitus and they are associated with increased lipid peroxidation. The selenium content of erythrocytes, whole blood and plasma, as well as of plasma glutathione peroxidase activity, were found to be low in the healthy Hungarian children compared to the healthy Germans. Both groups of diabetics had significantly higher blood selenium (1.05 +/- 0.14 versus 0.86 +/- 0.1 mumol/L in Hungarians, 1.34 +/- 0.21 versus 1.12 +/- 0.22 mumol/L in Germans) and higher plasma selenium (0.89 +/- 0.15 versus 0.68 +/- 0.01 mumol/L in Hungarians and 1.01 +/- 0.2 versus 0.88 +/- 0.19 mumol/L in Germans) than the healthy children of the same countries. In all diabetic children the plasma glutathione peroxidase activity and triglycerides were higher and the plasma HDL-cholesterols (HDLC = high density lipoprotein-cholesterol) lower than those in healthy controls. The patients showed linear correlations between blood glucose and plasma glutathione peroxidase activity, as well as in erythrocyte glutathione peroxidase activity with triglycerides (TG) and an inverse correlation with HDL-cholesterol. Plasma selenium correlated only in healthy children with triglycerides, cholesterol and HDL-cholesterol. Irrespective of the geographical region diabetics had a higher selenium status than healthy children. In addition, we found correlations between selenium and lipoproteins in the reference group. The mode of glycation, oxidative procedures and the selenium binding to lipoproteins could explain the different associations in the healthy and diabetic children.