BioMetals (v.22, #6)
Elemental fingerprinting of tumorous and adjacent non-tumorous tissues from patients with colorectal cancer using ICP-MS, ICP-OES and chemometric analysis by Isela Lavilla; Marta Costas; Pilar San Miguel; Jorge Millos; Carlos Bendicho (863-875).
Tumorous and adjacent non-tumorous paired biopsies from 38 patients with colorectal cancer were analyzed by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry after low-volume microwave digestion. 18 elements were investigated: Ag, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, S, Se and Zn. Different chemometric tools were used for data evaluation: Wilcoxon signed rank test, Hieratical clustering analysis, principal component analysis (PCA) and linear discriminant analysis (LDA). With the exception of Al, tumours were observed to have significantly more elevated concentrations of essential elements as compared to non-tumours. On the contrary, elements considered potentially carcinogenic such as Cr, Ni, Mo or Co do not display significant differences. When PCA was applied, different components were obtained for tumorous and non-tumorous tissues. When LDA was applied for the elements studied (including essential and non-essential elements) about 90% of cases were correctly classified.
Keywords: Colorectal cancer; Trace and minor elements; ICP-MS; ICP-OES; Chemometric analysis
Disturbances of energetic metabolism in rat epididymal epithelial cells as a consequence of chronic lead intoxication by M. Marchlewicz; I. Baranowska-Bosiacka; A. Kolasa; A. Kondarewicz; D. Chlubek; B. Wiszniewska (877-887).
Adult male Wistar rats were intoxicated with 1% lead acetate (PbAc) administered in drinking water for nine months, which amounts to a period five times longer than the duration of one spermatogenesis. There were mitochondrial ultrastructure disorders of epididymal epithelial cells observed in PbAc-treated rats; also a significant lead-induced decrease in ATP concentration in epididymal epithelial cells (by 32%, P < 0.05), Adenylate Energy Charge value (AEC) (by 8%, P < 0.05) and an increase in ADP (28.5%, P < 0.05), AMP (27%, P < 0.05) and adenosine (by 56%, P < 0.05). The results were measured using high performance liquid chromatography (HPLC) and detected even at low lead concentrations in whole blood (M:7.03 μg/dL; Q1–Q3: 2.99–7.65). The function of mitochondria in cultured epididymal epithelial cells of control and PbAc-treated animals were evaluated using fluorophores: Mitotracker Green FM and JC-1. After incubation with Mitotracker Green FM, we observed active mitochondria producing bright green fluorescence in the cytoplasm of cultured epididymal epithelial cells, both in the control group and the Pb-treated animals. Incubation of cultured epididymal epithelial cells of animals from both groups produced red-orange fluorescence with the mitochondrial JC-1 probe indicating mitochondria with high membrane potential (ΔΨm > 80–100 mV) and green fluorescence in the mitochondria with low membrane potential (ΔΨm <80 mV). The results showed that a chronic low-level exposure to lead, even without severe clinical symptoms of contamination, disrupted the ultrastructure and energy metabolism of mitochondria in epididymal epithelial cells.
Keywords: Lead; Epididymis; Energy metabolism; Mitochondrial probe
The gene frpB2 of Helicobacter pylori encodes an hemoglobin-binding protein involved in iron acquisition by Marco A. González-López; José J. Olivares-Trejo (889-894).
Human hemoglobin (Hb) is a metalloprotein used by pathogens as a source of iron during invasive process. It can support the Helicobacter pylori growth and several proteins are induced during iron starvation. However, the identity of those proteins remains unknown. In this work, by in silico analysis we identified FrpB2 in H. pylori genome. This protein was annotated as an iron-regulated outer membrane protein. Multiple amino acid alignment showed the motifs necessary for Hb-binding. We demonstrate the ability of FrpB2 to bind Hb by overlay experiments. In addition, the overexpression of this gene allowed the cell growth in media without free iron but supplemented with Hb. All these results support the idea that frpB2 is a gene of H. pylori involved in iron acquisition when Hb is used as a sole iron source.
Keywords: Hb-binding protein; Hemoglobin; H. pylori ; Iron starvation
Anti-diabetic effects of vanadium(III, IV, V)–chlorodipicolinate complexes in streptozotocin-induced diabetic rats by Ming Li; Wenjun Ding; Jason J. Smee; Bharat Baruah; Gail R. Willsky; Debbie C. Crans (895-905).
Vanadium(III, IV, V)–chlorodipicolinate (dipic-Cl) complexes, including H[VIII(dipic-Cl)2] · 5H2O (V3dipic-Cl), VIVO(dipic-Cl)(H2O)2 (V4dipic-Cl) and K[VVO2(dipic-Cl)] (V5dipic-Cl), were prepared with the indicated oxidation states. Our aim was to evaluate the anti-diabetic effects of V3dipic-Cl, V4dipic-Cl and V5dipic-Cl in streptozotocin-induced diabetic rats. Vanadium complexes were orally administered to diabetic rats at concentrations of 0.1–0.3 mg/ml in the drinking water. We found that vanadium–chlorodipicolinate (V–dipic-Cl) complexes at the concentration of 0.1 mg/ml did not exhibit blood glucose-lowering effects when administered to diabetic rats for 20 days. However, the levels of fasting blood glucose in diabetic rats were decreased after treatment with 0.3 mg/ml of V4dipic-Cl and V5dipic-Cl complexes for the following 20 days. Although administration of both V4dipic-Cl and V5dipic-Cl significantly lowered diabetic hyperglycemia, the vanadium intake from administration of V4dipic-Cl is nearly 1.5-fold greater compared to that of V5dipic-Cl. Treatment with the H2dipic-Cl ligand and all three V–dipic-Cl complexes significantly lowered serum cholesterol, while administration of the V5dipic-Cl complex lowered serum cholesterol significantly more than administration of the ligand alone. Treatment with ligand alone did not have an effect on serum triglyceride, while administration of the V4dipic-Cl and V5dipic-Cl significantly lowered the elevated serum triglyceride associated with diabetes. Oral administration of the ligand and all V–dipic-Cl complexes did significantly lower diabetes elevated serum alkaline phosphatase. Treatment with H2dipic-Cl ligand and V4dipic-Cl and V5dipicCl significantly lowered diabetes elevated aspartate amino transferase. These results indicate that the health of the treated animals did not seem to be further compromised compared to that of diabetic animals. In addition, oral administration of H2dipic-Cl, V3dipic-Cl, V4dipic-Cl and V5dipic-Cl did not alter diabetic serum creatinine and blood urea nitrogen levels, suggesting no significant side effects of vanadium treatment on renal functions at the dose of 0.3 mg/ml in diabetic rats. The results presented here suggest that the anti-diabetic effects of treatment with V–dipic-Cl complexes were likely associated in part with the oxidation state of vanadium.
Keywords: Vanadium; Chlorodipicolinate; Insulin-enhancing; Lipid; Redox; Diabetes
Transcriptional responses of Haemophilus parasuis to iron-restriction stress in vitro by Qiyun Xie; Hui Jin; Rui Luo; Yun Wan; Jie Chu; Hufeng Zhou; Bi Shi; Huanchun Chen; Rui Zhou (907-916).
Haemophilus parasuis is the causative agent of Glässer’s disease, which is responsible for the increasing economic losses in the pig industry worldwide. In this study, selective capture of transcribed sequences approach was used to investigate the transcriptional responses of H. parasuis to iron-restriction stress. Thirty-six genes were identified to be up-regulated under iron-restricted conditions. Knowledge of the genes involved in adaptation to environments encountered during disease will help understand the mechanisms of pathogenesis for this economically significant bacterium.
Keywords: Haemophilus parasuis ; Transcriptional responses; Iron restriction; Selective capture of transcribed sequences
Duality of effect of La3+ on mitochondrial permeability transition pore depending on the concentration by Shuai Dong; Yuebin Zhao; Huixue Liu; Xiaoda Yang; Kui Wang (917-926).
In order to explore the role of mitochondria in proliferation promotion and/or apoptosis induction of lanthanum, the mutual influences between La3+ and Ca2+ on mitochondrial permeability transition pore (PTP) opening were investigated with isolated mitochondria from rat liver. The experimental results revealed that La3+ influence the state of mitochondria in a concentration-dependent biphasic manner. La3+ in nanomolar concentrations, acting as a Ca2+ analog, entered mitochondrial matrix via the RuR sensitive Ca2+ channel and elevated ROS level, leading to opening of PTP indicated by mitochondrial swelling, reduction of ΔΨm and cytochrome c release. Inhibition of PTP with 10 μM CsA attenuated the effects of La3+. However, micromolar concentrations La3+ acted mainly as a Ca2+ antagonist, inhibiting PTP opening induced by Ca2+. We postulated that this action of La3+ on mitochondria through interaction with Ca2+ might be involved in the proliferation-promoting and apoptosis induction by La3+.
Keywords: Lanthanum ion; Mitochondria; Calcium ion; Permeability transition pore
Crystal structures, DNA-binding studies and antioxidant activities of the Ln(III) complexes with 7-methoxychromone-3-carbaldehyde-isonicotinoyl hydrazone by Qian Wang; Zheng-Yin Yang; Gao-Fei Qi; Dong-Dong Qin (927-940).
The neutral mononuclear Ln(III) complexes (Ln = La, Sm) with 7-methoxychrom-one-3-carbaldehyde-isonicotinoyl hydrazone ligand (L) have been synthesized, characterized and investigated their interactions with calf-thymus DNA. The results show that the binding affinity of the La(III) complex is stronger than that of the Sm(III) complex and that of the ligand (L). Furthermore, the antioxidant activities of the ligand (L) and its Ln(III) complexes (Ln = La, Sm) were studied in detail.
Keywords: 7-Methoxychromone-3-carbaldehyde-isonicotinoyl hydrazone; DNA-binding; Antioxidant activity; Rare earth complex
Influences of magnesium deficiency and cerium on antioxidant system of spinach chloroplasts by Yuguan Ze; Sitao Yin; Zhe Ji; Luyang Luo; Chao Liu; Fashui Hong (941-949).
Magnesium-deficiency conditions applied to spinach cultures caused an oxidative stress status in spinach chloroplast monitored by an increase in reactive oxygen species (ROS) accumulation. The enhancement of lipids peroxide of spinach chloroplast grown in magnesium-deficiency media suggested an oxidative attack that was activated by a reduction of antioxidative defense mechanism measured by analysing the activities of superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase, as well as antioxidants such as carotenoids and glutathione content. As the antioxidative response of chloroplast was reduced in spinach grown in magnesium-deficiency media, it caused a significant reduction of spinach plant weight, old leaves turning chlorosis. However, cerium treatment grown in magnesium-deficiency conditions decreased the malondialdehyde and ROS, and increased activities of the antioxidative defense system, and improved spinach growth. Together, the experimental study implied that cerium could partly substitute for magnesium and increase the oxidative stress-resistance of spinach chloroplast grown in magnesium-deficiency conditions, but the mechanisms need further study.
Keywords: Cerium; Magnesium-deficiency; Spinach; Chloroplast; Antioxidant system
Siderophore-mediated iron acquisition in the entomopathogenic bacterium Pseudomonas entomophila L48 and its close relative Pseudomonas putida KT2440 by Sandra Matthijs; Georges Laus; Jean-Marie Meyer; Kourosch Abbaspour-Tehrani; Mathias Schäfer; Herbert Budzikiewicz; Pierre Cornelis (951-964).
Pseudomonas entomophila L48 is a recently identified entomopathogenic bacterium which, upon ingestion, kills Drosophila melanogaster, and is closely related to P. putida. The complete genome of this species has been sequenced and therefore a genomic, genetic and structural analysis of the siderophore-mediated iron acquisition was undertaken. P. entomophila produces two siderophores, a structurally new and unique pyoverdine and the secondary siderophore pseudomonine, already described in P. fluorescens species. Structural analysis of the pyoverdine produced by the closely related P. putida KT2440 showed that this strain produces an already characterised pyoverdine, but different from P. entomophila, and no evidence was found for the production of a second siderophore. Growth stimulation assays with heterologous pyoverdines demonstrated that P. entomophila is able to utilize a large variety of structurally distinct pyoverdines produced by other Pseudomonas species. In contrast, P. putida KT2440 is able to utilize only its own pyoverdine and the pyoverdine produced by P. syringae LMG 1247. Our data suggest that although closely related, P. entomophila is a more efficient competitor for iron than P. putida.
Keywords: Pseudomonas ; Pyoverdine; Pseudomonine; Siderotyping; Mass spectrometry
Chemical and biological characterization of siderophore produced by the marine-derived Aureobasidium pullulans HN6.2 and its antibacterial activity by Weilin Wang; Zhe Chi; Guanglei Liu; Muhammad Aslam Buzdar; Zhenming Chi; Qianqun Gu (965-972).
After analysis using HPLC and electronic ion spray mass spectroscopy, the purified siderophore produced by the marine-derived Aureobasidium pullulans HN6.2 was found to be fusigen. The purified desferric fusigen still had strong inhibition of growth of the pathogenic Vibrio anguillarum while the fusigen chelated by Fe3+ lost the ability to inhibit the growth of the pathogenic bacterium. The added iron in the medium repressed expression of the hydroxylase gene encoding ornithine N5-oxygenase that catalyzes the N5-hydroxylation of ornithine for the first step of siderophore biosynthesis in the yeast cells while expression of the hydroxylase gene in the yeast cells grown in the medium plus ornithine was enhanced.
Keywords: Siderophore biosynthesis; Fusigen; A. pullulans ; Ornithine; Fe3+
The effect of dietary selenium supplementation on cadmium absorption and retention in suckling rats by Maja Lazarus; Tatjana Orct; Jasna Jurasoviæ; Maja Blanuša (973-983).
Selenium (Se) reduces cadmium (Cd) toxicity in adult animals, but its effects in newborn animals are still unknown. This study investigated Cd (as CdCl2) absorption, distribution, and retention in suckling rats receiving oral Se supplementation (as Na2SeO3) in equimolar doses (8 μmol Cd and/or Se per kg b.w./day). Selenium was given either before and during Cd exposure (Sepre + Cd group; pre-treatment group) or only during Cd exposure (Se + Cd group). Rats were treated from postnatal day (PND) 6–14 as follows: controls (H2O, PND 6–14), Se (PND 10–14), Cd (PND 10–14), Sepre + Cd (Se PND 6–14 + Cd PND 10–14) and Se + Cd (Se + Cd PND 10–14). Selenium supplementation, especially pre-treatment, decreased Cd levels in the blood, brain, liver and kidney of suckling rats. Selenium levels in plasma, brain, and kidney also decreased. These findings suggest that higher Se intake could efficiently reduce Cd retention during the suckling period.
Keywords: Cadmium; Selenium; Interaction; Suckling rat
Ovarian gene transcription and effect of cadmium pre-exposure during artificial sexual maturation of the European eel (Anguilla anguilla) by Fabien Pierron; Magalie Baudrimont; Sylvie Dufour; Pierre Elie; Angélique Bossy; Magalie Lucia; Jean-Charles Massabuau (985-994).
European eels are dangerously threatened with extinction. Recent advances tend to show that pollution could, in addition to other already identified factors, contribute to this drama. In a previous report, cadmium (Cd) pre-exposure was found to strongly stimulate the pituitary-liver-gonad axis of maturing female silver eels, leading, lastly, to oocytes atresia and eels mortality. The present work was performed to get more insights into the effects of Cd pre-exposure on eels’ ovaries. The transcription levels of various genes involved in mitochondrial metabolism, in the cellular response to metal (metallothioneins, MTs) and oxidative stress (catalase, CAT) were investigated. Our results show that ovarian growth is associated with an up-regulation of mitochondrial genes. However, Cd pre-exposure was found to significantly impair this up-regulation. Such findings could explain, at least in part, why oocytes of Cd pre-contaminated eels could not reach final maturation. Concerning MTs, despite the end of the experiment was marked by a strong increase in their gene transcription levels in both eel groups, MTs protein content was found to increase only in the case of Cd pre-contaminated eels. Since this increase in MTs protein content was associated with a massive entry of Cd in gonads, our findings suggest that MTs mRNA, that are normally accumulated in oocytes to cope with the future needs, can be activated and translated in response to Cd exposure.
Keywords: Anguilla anguilla ; Gene transcription; Metallothioneins; Mitochondria; Oocytes
Selenoprotein P regulation by the glucocorticoid receptor by Colleen Rock; Philip J. Moos (995-1009).
Maintenance of the antioxidant activity of selenoproteins is one potential mechanism of the beneficial health effects of selenium. Selenoprotein P is the primary selenium distribution protein of the body as well as the major selenium containing protein in serum. The transcriptional regulation of selenoprotein P is of interest since the extrahepatic expression of this gene has demonstrated differentiation-dependent expression in development as well as under different disease states. SEPP1 displays patterned expression in numerous tissues during development and the loss of SEPP1 expression has been observed in malignancy. In addition, factors that influence inflammatory processes like cytokines and their regulators have been implicated in selenoprotein P transcriptional control. Herein, we identify a retinoid responsive element and describe a mechanism where the glucocorticoid receptor negatively regulates expression of selenoprotein P. Luciferase reporter assays and quantitative PCR were used to measure selenoprotein P transcription in engineered HEK-293 cells. When stimulated with ecdysone analogs, selenoprotein P expression was increased with the use of a fusion transcription factor that contains the glucocorticoid receptor DNA binding domain, an ecdysone ligand-binding domain, and a strong transactivation domain as well as the retinoid X receptor. The native glucocorticoid receptor inhibited selenoprotein P transactivation, and selenoprotein P was further attenuated in the presence of dexamethasone. Our results may provide insight into a potential mechanism by which selenium is redistributed during development, differentiation or under conditions of critical illness, where glucocorticoid levels are typically increased.
Keywords: Selenoprotein P; Glucocorticoid receptor; Glucocorticoids; Antioxidant; Retinoids
Biochemical characterization of Helicobacter pylori α-1,4 fucosyltransferase: metal ion requirement, donor substrate specificity and organic solvent stability by Said Rabbani; Francesco Corona; Beat Ernst (1011-1017).
The effect of metal ions on the activity, the donor substrate specificity, and the stability in organic solvents of Helicobacter pylori α-1,4 fucosyltransferase were studied. The recombinant enzyme was expressed as soluble form in E. coli strain AD494 and purified in a one step affinity chromatography. Its activity was highest in cacodylate buffer at pH 6.5 in the presence of 20 mM Mn2+ ions at 37°C. Mn2+ ions could be substituted by other metal ions. In all cases, Mn2+ ions proofed to be the most effective (Mn2+ > Co2+ > Ca2+ > Mg2+ > Cu2+ > Ni2+ > EDTA). The enzyme shows substrate specificity for Type I disaccharide (1) with a K M of 114 μM. In addition, the H. pylori α-1,4 fucosyltransferase efficiently transfers GDP-activated l-fucose derivatives to Galβ1-3GlcNAc-OR (1). Interestingly, the presence of organic solvents such as DMSO and methanol up to 20% in the reaction medium does not affect significantly the enzyme activity. However, at the same concentration of dioxane, activity is totally abolished.
Keywords: Helicobacter pylori ; α-1,4 Fucosyltransferase; Metal ions; Donor substrate; Organic solvents
Hydroxamate siderophores of Scedosporium apiospermum by Samuel Bertrand; Gérald Larcher; Anne Landreau; Pascal Richomme; Olivier Duval; Jean-Philippe Bouchara (1019-1029).
Scedosporium apiospermum is an emerging pathogen colonizing the airways of patients with cystic fibrosis and causing severe infections in immunocompromised hosts. In order to improve our knowledge on the pathogenic mechanisms of this fungus, we investigated the production of siderophores. Cultivation on CAS medium and specific assays for different classes of siderophores suggested the secretion of hydroxamates. A maximal production was obtained by cultivation of the fungus at alkaline pH in an iron-restricted liquid culture medium. Siderophores were then extracted from the culture filtrate by liquid/liquid extraction, and separated by reverse phase high performance liquid chromatography. Two siderophores, dimerumic acid and N α-methyl coprogen B, were identified by electrospray ionization-mass spectrometry and MS–MS fragmentation. Finally, comparison of various strains suggested a higher production of N α-methyl coprogen B by clinical isolates of respiratory origin. Studies are initiated in order to determine the potential usefulness of these siderophores as diagnostic markers of scedosporiosis.
Keywords: Scedosporium apiospermum ; Hydroxamate-type siderophores; N α-methyl coprogen B; Dimerumic acid
Comparison of inhibitory activities of zinc oxide ultrafine and fine particulates on IgE-induced mast cell activation by Kouya Yamaki; Shin Yoshino (1031-1040).
The effects of ultrafine and fine particles of zinc oxide (ZnO) on IgE-dependent mast cell activation were investigated. The rat mast cell line RBL2H3 sensitized with monoclonal anti-ovalbumin (OVA) IgE was challenged with OVA in the presence or absence of ZnO particles and zinc sulfate (ZnSO4). Degranulation of RBL2H3 was examined by the release of β-hexosaminidase. To understand the mechanisms responsible for regulating mast cell functions, the effects of ZnO particles on the levels of intracellular Zn2+, Ca2+, phosphorylated-Akt, and global tyrosine phosphorylation were also measured. IgE-induced release of β-hexosaminidase was obviously attenuated by ultrafine ZnO particles and ZnSO4, whereas it was very weakly inhibited by fine ZnO particles. The intracellular Zn2+ concentration was higher in the cells incubated with ultrafine ZnO particles than in those with fine ZnO particles. Consistent with inhibitory effect on release of β-hexosaminidase, ultrafine ZnO particles and ZnSO4, but not fine ZnO particle, strongly attenuated the IgE-mediated increase of phosphorylated-Akt and tyrosine phosphorylations of 100 and 70 kDa proteins in RBL2H3 cells. These findings indicate that ultrafine ZnO particles, with a small diameter and a large total surface area/mass, could release Zn2+ easily and increase intracellular Zn2+ concentration efficiently, thus decreasing FcεRI-mediated mast cell degranulation through inhibitions of PI3K and protein tyrosine kinase activation. Exposure to ZnO particles might affect immune responses, especially in allergic diseases.
Keywords: IgE; Nanoparticles; Degranulation; Mast cell; Zinc oxide; PI3K
Disturbed homeostasis of zinc and other essential elements in the prostate gland dependent on the character of pathological lesions by Andrzej Sapota; Adam Daragó; Jan Taczalski; Anna Kilanowicz (1041-1049).
Pathophysiological changes in the prostate take the form of benign prostate hyperplasia (BPH) and prostate adenocarcinoma (PCa). In prostate, zinc is particularly important to its normal functioning, especially in terms of the consequences of hormone disturbance. The aim of this study was to assess the levels of Zn, Cu, Ca, Mg, and Se in the prostate dependent on the character of patological changes. Zinc, copper, magnesium and calcium were determined by AAS and selenium with spectrofluorometric method. Zn levels in BPH patients were over twofold higher than in controls. On the other hand, in the patients with PCa, the levels of Zn were found almost three times lower than in BPH patients and by almost 50% lower than in controls. In this study, significant changes in the levels of other essential elements were observed. The results apparently confirm the disturbed homeostasis of zinc and other essential elements in the etiology of BPH and PCa.
Keywords: Zinc; Copper; Calcium; Magnesium; Selenium; Prostate; Cancer; Hyperplasia
Deficiency in frataxin homologue YFH1 in the yeast Pichia guilliermondii leads to missregulation of iron acquisition and riboflavin biosynthesis and affects sulfate assimilation by Yuriy V. Pynyaha; Yuriy R. Boretsky; Daria V. Fedorovych; Lubov R. Fayura; Andriy I. Levkiv; Vira M. Ubiyvovk; Olha V. Protchenko; Caroline C. Philpott; Andriy A. Sibirny (1051-1061).
Pichia guilliermondii is a representative of yeast species that overproduce riboflavin (vitamin B2) in response to iron deprivation. P. guilliermondii YFH1 gene coding for frataxin homologue, eukaryotic mitochondrial protein involved in iron trafficking and storage, was identified and deleted. Constructed P. guilliermondii Δyfh1 mutant grew very poorly in a sucrose-containing synthetic medium supplemented with sulfate or sulfite as a sole sulfur source. Addition of sodium sulfide, glutathione, cysteine, methionine, N-acetyl-l-cysteine partially restored growth rate of the mutant suggesting that it is impaired in sulfate assimilation. Cellular iron content in Δyfh1 mutant was ~3–3.5 times higher as compared to the parental strain. It produced 50–70 times more riboflavin in iron sufficient synthetic media relative to the parental wild-type strain. Biomass yield of the mutant in the synthetic glutathione containing medium supplemented with glycerol as a sole carbon source was 1.4- and 2.6-fold increased as compared to sucrose and succinate containing media, respectively. Oxygen uptake of the Δyfh1 mutant on sucrose, glycerol or succinate, when compared to the parental strain, was decreased 5.5-, 1.7- and 1.5-fold, respectively. Substitution of sucrose or glycerol in the synthetic iron sufficient medium with succinate completely abolished riboflavin overproduction by the mutants. Deletion of the YFH1 gene caused hypersensitivity to hydrogen peroxide and exogenously added riboflavin and led to alterations in superoxide dismutase activities. Thus, deletion of the gene coding for yeast frataxin homologue has pleiotropic effect on metabolism in P. guilliermondii.
Keywords: Frataxin; Iron; Riboflavin; Yeast; Sulfate; Respiration
Purification and characterization of mycoferritin from Fusarium verticillioides MRC 826 by Vakdevi Validandi; Karuna Rupula; Sashidhar Rao Beedu; Vijay Deshpande (1063-1073).
The fungus Fusarium verticillioides MRC 826 (ascomycetes species), a toxigenic isolate is capable of synthesizing mycoferritin only upon induction with iron in yeast extract sucrose medium. The molecular mass, yield, iron and carbohydrate contents of the purified mycoferritin were 460 kDa, 0.010 mg/g of wet mycelia, 1.0 and 40.2%, respectively. Native gel electrophoresis of the mycoferritin revealed two bands possibly representing isoforms of ferritin. Subunit analysis by SDS–PAGE showed a single protein subunit of ~24 kDa suggesting similar sized subunits in the structure of apoferritin shell. Immunological cross reactivity was observed with the anti-fish liver ferritin. Transmission electron microscopy revealed an apparent particle size of 100 Å. N-terminal amino acid sequencing of mycoferritin showed identities with other eukaryotic ferritin sequences. The spectral characteristics were similar to equine spleen ferritin. However, circular dichroic spectra revealed a higher degree of helicity. Functionally, induction of mycoferritin minimizes the pro-oxidant role of iron.
Keywords: Mycoferritin; Molecular weight; N-terminal amino acid sequence; Glycoprotein; Fumonisin B1 ; Pro-oxidant
Effect of chromium supplementation on the diabetes induced-oxidative stress in liver and brain of adult rats by Fawzia M. Refaie; Amr Y. Esmat; Aly F. Mohamed; Wael H. Aboul Nour (1075-1087).
This study was designed to investigate the susceptibility of liver and brain tissues, as insulin-independent tissues, of normal adult male rats to the oxidative challenge of subchronic supplementation with chromium picolinate (CrPic) at low (human equivalent) and high doses (2.90 and 13.20 μg Cr kg−1 day−1, respectively). Also, the modulative effect of CrPic administration on the enhanced oxidative stress in the liver and brain tissues of alloxan-diabetic rats was studied. Fasting serum glucose level was not modified in normal rats but significantly reduced in diabetic rats that had received CrPic supplement. A mild oxidative stress was observed in the liver and brain of CrPic-supplemented normal rats confirmed by the dose-dependent reductions in the levels of hepatic and cerebral free fatty acids, superoxide dismutase and glutathione peroxidase activities, and in contrast increased tissue malondialdehyde concentration. On the other hand, hepatic and cerebral catalase activity was reduced in the high dose group only. CrPic supplementation did not act as a peroxisome proliferator confirmed by the significant reductions in liver and brain peroxisomal palmitoyl CoA oxidase activity. The non significant alterations in liver protein/DNA and RNA/DNA ratios indicate that CrPic did not affect protein synthesis per cell, and that mild elevations in hepatic total protein and RNA concentrations might be due to block or decrease in the export rate of synthesized proteins from the liver to the plasma. In diabetic rats, elevated levels of hepatic and cerebral free fatty acids and malondialdehyde, and in contrast the overwhelmed antioxidant enzymes, were significantly modulated in the low dose group and near-normalized in the high dose group. The significant increases observed in liver total protein and RNA concentrations, as well as protein/DNA and RNA/DNA ratios in diabetic rats supplemented with the high dose of Cr, compared to untreated diabetics, may be related to the improvement in the glycemic status of the diabetic animals rather than the direct effect of CrPic on protein anabolism.
Keywords: Chromium picolinate; Alloxan-diabetes; Liver; Brain; Glucose; Palmitoyl CoA oxidase; Free fatty acids; Malondialdehyde; Antioxidant enzymes; Protein; Nucleic acids
Effects of tellurite on growth of Saccharomyces cerevisiae by Domenica R. Massardo; Paola Pontieri; Loredana Maddaluno; Mario De Stefano; Pietro Alifano; Luigi Del Giudice (1089-1094).
The effects of potassium tellurite on growth and survival of rho+ and rho0 Saccharomyces cerevisiae strains were investigated. Both rho+ and rho0 strains grew on a fermentable carbon source with up to 1.2 mM K2TeO3, while rho+ yeast cells grown on a non-fermentable carbon source were inhibited at tellurite levels as low as 50 μM suggesting that this metalloid specifically inhibited mitochondrial functions. Growth of rho+ yeast cells in the presence of increasing amount of tellurite resulted in dose-dependent blackening of the culture, a phenomenon not observed with rho0 cultures. Transmission electron microscopy of S. cerevisiae rho+ cells grown in the presence of tellurite showed that blackening was likely due to elemental tellurium (Te0) that formed large deposits along the cell wall and small precipitates in both the cytoplasm and mitochondria.
Keywords: Tellurite; Saccharomyces cerevisiae ; Mitochondria; Transmission electronic microscopy
Synthesis, characterization and evaluation of antileishmanial activity of copper(II) with fluorinated α-hydroxycarboxylate ligands by Rodrigo da Silva Maffei; Jenicer K. U. Yokoyama-Yasunaka; Danilo Ciccone Miguel; Silvia Reni Bortolin Uliana; Breno Pannia Espósito (1095-1101).
In this study, Cu(II) complexes with fluorinated ligands were produced aiming at the development of new, less toxic antileishmanial metallodrugs. Complexes of the general formula CuL2 (L = lactate, trifluorolactate, 2-hydroxyisobutyrate, trifluoro-2-hydroxyisobutyrate) were synthesized in methanolic medium, purified by crystallization and characterized by elemental analysis and electronic and infrared spectroscopies. In vitro experiments with Leishmania amazonensis promastigotes showed that the trifluorolactate derivative more active than its non-fluorinated counterpart. Our results indicate that fluorinated chelators may be interesting to increase metal toxicity and/or open new paths for metallodrug chemotherapy against leishmaniasis.
Keywords: Leishmaniasis; Neglected disease; Copper; Fluorine
Assessment of chronic mercury exposure within the U.S. population, National Health and Nutrition Examination Survey, 1999–2006 by Dan R. Laks (1103-1114).
The purpose of this study was to assess chronic mercury exposure within the US population. Time trends were analyzed for blood inorganic mercury (I-Hg) levels in 6,174 women, ages 18–49, in the NHANES, 1999–2006 data sets. Multivariate logistic regression distinguished a significant, direct correlation within the US population between I-Hg detection and years since the start of the survey (OR = 1.49, P < 0.001). Within this population, I-Hg detection rose sharply from 2% in 1999–2000 to 30% in 2005–2006. In addition, the population averaged mean I-Hg concentration rose significantly over that same period from 0.33 to 0.39 μ/L (Anova, P < 0.001). In a separate analysis, multivariate logistic regression indicated that I-Hg detection was significantly associated with age (OR = 1.02, P < 0.001). Furthermore, multivariate logistic regression revealed significant associations of both I-Hg detection and mean concentration with biomarkers for the main targets of mercury deposition and effect: the liver, immune system, and pituitary. This study provides compelling evidence that I-Hg deposition within the human body is a cumulative process, increasing with age and in the population over time, since 1999, as a result of chronic mercury exposure. Furthermore, our results indicate that I-Hg deposition is associated with the significant biological markers for main targets of exposure, deposition, and effect. Accumulation of focal I-Hg deposits within the human body due to chronic mercury exposure provides a mechanism which suggests a time dependent rise in the population risks for associated disease.
Keywords: Mercury; NHANES; Pituitary; Luteinizing hormone; Autism; Alzheimer’s disease