Search results for "selenium"
showing 10 items of 178 documents
Hg and Se exposure in brain tissues of striped dolphin (Stenella coeruleoalba) and bottlenose dolphin (Tursiops truncatus) from the Tyrrhenian and Ad…
2017
In this study we analyzed Hg and Se concentrations in dolphin brain tissues of fifteen specimens of striped dolphin (Stenella coeruleoalba) and eight specimens of bottlenose dolphin (Tursiops truncatus) stranded in the Tyrrhenian and Adriatic Seas, in order to assess the toxicological risks associated with Hg exposure. High Hg concentrations were found in brain tissues of both analyzed specie (1.86–243 mg/kg dw for striped dolphin and 2.1–98.7 mg/kg dw for bottlenose dolphin), exceeding levels associated with marine mammals neurotoxicity. Althougth the results clearly suggest that the protective effects of Se against Hg toxicity occur in cetaceans’ brain tissues, a molar excess of mercury w…
Physical–chemical properties of biogenic selenium nanostructures produced by stenotrophomonas maltophilia SeITE02 and ochrobactrum sp. MPV1
2018
Stenotrophomonas maltophilia SeITE02 and Ochrobactrum sp. MPV1 were isolated from the rhizosphere soil of the selenium-hyperaccumulator legume Astragalus bisulcatus and waste material from a dumping site for roasted pyrites, respectively. Here, these bacterial strains were studied as cell factories to generate selenium-nanostructures (SeNS) under metabolically controlled growth conditions. Thus, a defined medium (DM) containing either glucose or pyruvate as carbon and energy source along with selenite (SeO23−) was tested to evaluate bacterial growth, oxyanion bioconversion and changes occurring in SeNS features with respect to those generated by these strains grown on rich media. Transmissi…
Optimization of Bacillus cereus Fermentation Process for Selenium Enrichment as Organic Selenium Source
2020
Selenium is an essential trace element and micronutrient for human health. Application of organic selenium in plants and microorganisms as trace element supplement is attracting more and more attention. In this study, Bacillus cereus, an important probiotic, was used for selenium enrichment with sodium selenite as selenium source. The growth curve of B. cereus was investigated, and 150 μg/ml was selected as the concentration of selenium for B. cereus fermentation. With application of response surface methodology, the optimal fermentation conditions were obtained as follows: inoculation quantity of 7%, culture temperature of 33°C, and shaking speed of 170 rpm, leading to the maximal selenium…
Mineral essential elements for nutrition in different chocolate products
2016
In this work, the essential mineral nutritional elements in cocoa beans, in chocolates at different cocoa percentage (60,70,80 and 90%) and in milk chocolate are evaluated. Dark chocolates are confirmed as an excellent source of magnesium (252.2 mg/100 g) and iron (10.9 mg/100 g): in chocolate containing 90% cocoa, their content corresponds to, respectively, 67.0% and 80.3 of Nutrient Reference Values (NRV) in the European Union. The chocolate containing 90% cocoa is also a good source of zinc (3.5 mg/100 g), which is important for the immune system, and selenium (0.1 mg/100 g). Three main components suitable to explain the mineral concentrations are analyzed by factor analysis. The compone…
Selenomethionine labeling of large biological macromolecular complexes: probing the structure of marine bacterial virus PM2.
2008
There is a need for improved tools for labeling protein species within large macromolecular assemblies. Here we describe a method for the efficient selenomethionine labeling of the membrane-containing bacterial virus PM2 for structural studies. By examining potential host cells a strain was found which was auxotrophic for methionine, and by performing a multiparameter search of conditions it was possible to derive a robust protocol which simultaneously minimized the toxic effects of the selenomethionine, so that a reasonable virus yield was maintained, whilst still achieving essentially complete labeling. This has allowed us to fingerprint the protein constituents of the virus in a relative…
Effectiveness of microwave based digestion procedures for the demineralization of human milk and infant formulas prior to fluorometric determination …
1996
The use of two types of microwave oven, one domestic (A) and the other specially designed for laboratory (B) for microwave-based digestion, to destroy the organic matter in milk and infant formulas prior to fluorometric determination of selenium is studied in order to check their applicability and reliability. In both systems the best results were obtained using the acid mixture HNO3—H2O2, and additional treatment with perchloric acid (60%) in a Thermoblock. The application of two different microwave-based digestion procedures to infant formulas was free of interferences. In the case of human milk, it was necessary to use the standard addition method. Values obtained for detection and quant…
Selenium status during pregnancy: Influential factors and effects on neuropsychological development among Spanish infants
2017
Selenium(Se) has been positively associated with neurodevelopment in early life. However, its margin of safety is rather narrow, and few prospective studies have evaluated its potential neurotoxic effects at intermediate levels. We aimed to explore the association between maternal Se concentrations and child neuropsychological development, including the genetic effect modification of the Se metabolizing gene INMT. Study subjects were 650 mother-child pairs from the Spanish Childhood and Environment Project (INMA, 2003-2005). Infant neuropsychological development was assessed around 12 months of age by the Bayley Scales of Infant Development. Sociodemographic and dietary characteristics were…
Selenium, zinc and copper in plasma of patients with type 1 diabetes mellitus in different metabolic control states
1998
The Studies of selenium (Se), zinc (Zn) and copper (Cu) levels in diabetic patients have led to contradictory findings as the possible relationship between the degree of diabetic control and the changes in mineral contents. In the present study the plasma Cu, Se, and Zn contents of diabetic patients and healthy people were measured and the relationship between these contents and diabetic metabolic control, as determined by glycosylated hemoglobin (HbA1c), was studied. The mean plasma Se content in diabetic patients was significantly lower than in controls (p < 0.01) and a negative correlation between the plasma contents of Se and HbA1c was found. No statistically significant differences in …
Whole blood selenium content in pregnant women
1999
The selenium content in the blood of pregnant women in the Valencian Community, Spain was determined until the end of gestation in order to assess its evolution and detect possible differences in relation to the values corresponding to non-pregnant women of fertile age. A total of 158 blood samples were obtained from 137 pregnant women. Samples were classified as: (a) first; (b) second; and (c) third trimester. Selenium was determined by a flow injection hydride atomic absorption spectrometric method (Seronorm whole blood was used as a quality control check). The selenium values obtained for the three trimesters followed a Gaussian distribution. The intervals for mean found were: (a) 75.7-8…
Diastereoselective Synthesis of 2-Phenylselenenyl-1,3-anti-Diols and 2-Phenylselenenyl-1,3-anti-Azido-Alcohols via Hydroxy- and Azido-Selenenylation …
2005
A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.