Studies on zinc- and cadmium-bound proteins in bovine kidneys by biochemical and neutron activation techniques

Bovine kidneys were found to contain about 78 ppm Zn and 0.78 ppm Cd. Approximately 45% of Zn and 60% of Cd were present in the cytosol fraction. More than 95% of these two metals were bound to macromolecules. Both Zn- and Cd-protein complexes were observed to be stable between pH 7 and 10.5. Separation and characterization of these proteins were carried out using several chromatographic and electrophoretic techniques in conjunction with instrumental neutron activation analysis (INAA). The results showed the presence of at least four Zn-binding proteins with mol wt>300,000, 260,000, 89,000, and 27,000 and at least three Cd-binding proteins of mol wt>300,000, 32,000, and 13,000.     

Metabolic deposition of selenium and cadmium into the hair and other tissues of the guinea pig

To better understand the significance of hair trace-element measurements and their relationships with the trace-element levels in body organs and fluids, a series of controlled animal experiments were conducted in which several trace elements were periodically measured during a 90-day chronic exposure to selenium and cadmium. Chronic selenium exposure appeared to be reflected by elevated selenium levels in the hair, kidneys, and liver. Chronic cadmium exposure, although reflected by kidney and liver elevation, appeared not to be reflected by corresponding increases in its concentration in the hair.     

Determination of selenium in duplicate diets of residents of Pinhel,Portugal, by neutron activation

A rapid cyclic instrumental neutron activation analysis (CINAA) method has been used to determine the selenium content of 27 duplicate diet samples from each of the 27 districts surrounding Pinhel, Portugal. The accuracy and precision of the CINAA method have been evaluated by analyzing certified reference materials and observed to be within ±5–10% for samples containing at least 40 ppb of selenium. The detection limit has been found to vary between 26–42 ppb selenium depending on the sample composition. The average daily dietary intake has been calculated as 37 μg of selenium per day.     

Characterization of somatic embryogenesis in sandalwood (Santalum album L.)

In the synchronous embryogenesis system of sandalwood developed in our laboratory, we observed that the early events of differentiation from freshly induced callus (stage 0) are accomplished in three distinct stages viz., preglobular masses (stage 1), globular embryos (stage 2), and bipolar embryos (stage 3). Transition from stage 0 to 1 was accomplished using 2,4-D and involves a stage specific appearance of two polypeptides of 15 and 30 kDa molecular weight. A 24 kDa polypeptide that was detected as a marked band in extracts of primary callus was not detected in stages 1, 2, and 3. Further, the tissue level of a 50 kDa glycoprotein decreased during transition from stage 2 to stage 3. However, the levels of glycoproteins in the medium were markedly higher in stage 0 cultures compared to those in stage 1. The activities of a protein kinase, glycosidase, and xylanase increased markedly with progressing embryogenesis. Our observations suggest that in addition to being controlled at the level of stage-specific gene expression, somatic embryogenesis in sandalwood is also regulated at the level of controls on cell wall flexibility and posttranslational changes in the pool of preexisting proteins.     

Spatial distribution of extractable organohalogens in northern pink shrimp in the North Atlantic

Extractable organohalogens (EOX) are organic compounds that contain chlorine, bromine and/or iodine, which can be separated from the matrix by liquid/liquid or liquid/solid extraction. A combination of instrumental neutron activation analysis (INAA) and solvent extraction methods has been developed for the determination of EOX from the shrimpPandalus borealis. Levels of EOX were evaluated for spatial trends for shrimp caught in several areas off the Labrador coast, off the coast of Nova Scotia, and off the coast of Maine. Muscle contained 1.09–6.05 Μg EOCl/g tissue and 105–498 Μg extractable organochlorine (EOCl)/g lipid; 0.0607–0.288 Μg extractable organobromine (EOB)r/g tissue and 4.74-10.5 Μg EOBr/g lipid; and 0.014–0.048 Μg extractable organoiodine (EOI)/g tissue and 1.03–1.76 Μg EOI/g lipid, respectively. The levels of EOC1 in roe were 1.60–12.34 Μg/g tissue and 39.0-146 Μg/g lipid. In roe, the EOBr levels were 0.707–1.03 Μg/g tissue and 6.96–13.5 Μg/g lipid; and EOI levels were 0.123–0.349 Μg/g tissue and 1.42–4.11 Μg/g lipid. The EOCl, EOBr, and EOI levels in roe increased noticeably from north to south along the coast of Labrador. Samples taken from the coast of Maine and from Canso Hole were typically higher in EOCl levels than those taken from Labrador. The results for EOBr and EOI were in the same range as those from Labrador.     

Correlation between total and EDTA/DTPA-extractable trace elements in soil and wheat

Wheat and wheat products are more important sources of energy and nutrients in diets of people in many cultures compared to other foods. The daily consumption of wheat is about 200 g/d/person in Western Europe and North America. On the other hand, 400–450 g of wheat and wheat products are consumed daily by average Turkish people. Wheat samples collected from the Iskenderun region in 1995 and 1996 and Ankara and Istanbul regions in 1995 were analyzed for their trace element content by instrumental neutron activation analysis (INAA). In addition, 13 soil samples were collected from the Iskenderun region in 1996. Total soil samples were analyzed by INAA and atomic absorption spectrometry (AAS), EDTA-extractable elements by INAA, and DTPA-extractable elements by AAS. Correlation analysis and enrichment factor calculations were applied to the trace element results. In wheat samples, a strong correlation was found between the elements such as Sc, La, Sm, Rb, and K whose main source is soil. The concentration of Se appeared to show larger variations among different regions. No significant correlation was observed for elements such as As and Se whose main sources in the atmosphere are anthropogenic activities.     

Determination of selenium in canadian food items by cyclic instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) and pseudocyclic INAA (PCINAA) have been used to determine the selenium content of a variety of Canadian food items. Use of the 162-keV gamma ray of short-lived^77mSe in INAA allowed relatively simple and rapid determinations and was suitable for many of the foods. PCINAA was found to give lower detection limits and was used for the low-selenium food samples. Both internal and external quality assessments were used to evaluate and assure the accuracy and precision of the methods developed.     

Trace element contents in food determined by neutron activation analysis and other techniques

Biological Trace Element Research - Advances in analytical methodology and sophisticated instrumentation introduced during the last few decades have not only helped to recognize the presence of a...