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Pichia guilliermondii cells overproduce riboflavin (vitamin B2) in responce to iron deprivation. The increase in ferrireductase activity in iron-starved P. guilliermondii cells correlated with the increase in flavin excretion. As in Saccharomyces cerevisiae, a typical b-type cytochrome spectrum was associated with the plasma membrane fraction of P. guillermondii and the cell ferrireductase...
Inorganic selenium compounds in the diet have been known to protect against cancer in laboratory animals, but were harmful in high concentrations. In the present work, the relative effects of two salts, sodium selenite and sodium selenate, administered to mice in vivo, in different concentrations and durations of exposure, were compared. Aqueous solutions of each salt (7, 14, 21 and 28 mg Kg−1 bw)...
The main goal of this study was to investigate the role of cadmium in the promotion of lipid peroxidation in the homogenates of rat testes and the effect of selenium on lipid peroxidation in testes of rats after cadmium injection. Treatment of rats with cadmium resulted in a time- and dose-related accumulation of the metal ions in testes. The concentrations of cadmium, copper, zinc, selenium and iron...
Antioxidant properties of selenium producing a protective barrier against free radicals play an important role in numerous metabolic and immunologic processes associated with oxidation- reduction reactions which take place during intracellular digestion of phagocyted bacteria. The aim of our study was to examine the properties of an organic compound of selenium, 4-(o-tolilo)- selenosemicarbazide of...
Copper-induced metallothionein (MT) synthesis in Saccharomyces cerevisiae was investigated in order to associate this exclusively with Cu2+in vivo, when cultured in nutrient medium containing other heavy metal ions. Expression of the CUP1 promoter/lacZ fusion gene was inhibited by all heavy metal ions tested, especially Cd2+ and Mn2+. By adding Cd2+ and Mn2+ at 10 μM concentration, the β-galactosidase...
This paper examines the effects of ionic gold on Saccharomyces cerevisiae, as determined by long-term (growth in gold-containing media) and short-term interactions (H+ efflux activity). An increasing gold concentration inhibited growth and at <0.2 mM Au, growth was not observed. Transmission electron microscopy revealed no differences in ultrastructure but fine electron dense particles were observed...
Several suggestions for structures of the siderophores (pyoverdins) from Pseudomonas spp. can be found in the literature which are based on a FAB mass spectrometric analysis only. Availability of two original strains of two Pseudomonas spp. allowed to re-investigate the structure of their pyoverdins. In both cases the amino acid sequence had to be corrected. In addition, d- and l-amino acids could...
Previous in vitro studies have demonstrated zinc (Zn++) inhibition of basal and of potassium (K+) or thyrotropin-releasing hormone (TRH)-stimulated prolactin (PRL) secretion, in a selective, reversible, and dose-dependent manner. Thus, Zn++ may regulate physiologically pituitary PRL secretion. Furthermore, studies with patients with uremia, cirrhosis or prolactinoma, have shown the coexistence of...
Transport and metabolization of iron bound to the fungal siderophore rhizoferrin was analyzed by transport kinetics, Mössbauer and EPR spectroscopy. Saturation kinetics (vmax=24.4 pmol/(mg min), Km=64.4μM) and energy dependence excluded diffusion and provided evidence for a rhizoferrin transport system in M. smegmatis. Based on the spectroscopic techniques indications for intracellular presence...
Energy dispersive X-ray fluorescence technique was employed to study the interactions among various elements, viz.: K, Zn, Br, Fe, Cu, Br & Rb in 4 groups of rats viz. control-GI, diabetic- GII (diabetes induced by i.p administration of alloxan monohydrate at a dose level of 150 mg/kg b.w; single injection), lithium treated-GIII ( lithium administered as Li2 Co3 at a dose level of 1.1 g of Li2...
An unknown siderophore (pyoverdin) was isolated from the strain Pseudomonas sp. 2908. The structure of the pyoverdin – called PVD 2908 – was elucidated by spectroscopic methods and degradation studies. Some other siderophores were identified by LC/ESI-MS-screening based on the knowledge of PVD 2908.
Transport proteins of microorganisms may either belong to the ATP-binding cassette (ABC) superfamily or to the major facilitator (MFS)-superfamily. MFS transporters are single-polypeptide membrane transporters that transport small molecules via uniport, symport or antiport mechanisms in response to a chemiosmotic gradient. Although Saccharomyces cerevisiae is a non-siderophore producer, various bacterial...
Nickel sulphate was administered orally to adult male mice at dose level of 5 and 10 mg/kg body weight (5 days per week) for 35 days. There was no change in body weight. However a significant decrease in absolute and organ-to-body weight ratios of testes, epididymides, seminal vesicles and prostate gland was observed. The sperm abnormality, associated with decrease in sperm motility and sperm count...
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