Radioactive and conventional pollutants accumulated by edible mushrooms (Boletus sp.) are useful indicators of species origin.

Concentrations of artificial radionuclides and trace elements in Boletus samples collected in different areas of the world were detected, respectively, by gamma spectrometry and neutron activation analysis. The particular commercial value of Boletus edulis, B. aestivalis, and B. pinophilus from the Taro Valley (Parma, Italy) has often stimulated local factories to trade edible Boletus imported from several areas of the world as the real Taro Valley mushroom. Starting from this evidence, the calculation of the Chernobyl radioactive contamination in the mushrooms coupled with the presence of particular stable elements and their concentration factors has been demonstrated to be a potential useful tool for identifying the real origin of the samples. In fact, major differences in the radiocesium activity levels and trace element presence were observed even in mushrooms collected in nearby valleys. The radiometric data are supported by the statistical analysis. In particular, both the principal component analysis and the concentration distribution along a regression line support the idea of two different clusters: one referred to the "king boletus" of the Taro Valley and another one to the other conspecific samples from different ecosystems.

The comparative effect of ovarian hormone administration on bone mineral status in oophorectomized rats.

The effect of oophorectomy and hormone replacement therapy on cortical and trabecular bone mass was assessed in Sprague-Dawley rats. Bone mineral density (BMD) of the femur and the lumbar spine was determined by dual photon absorptiometry 4 months after surgery. Femoral mineral content was also determined. A significant decrease in bone density and in calcium content was observed after surgical castration. Bone mineral loss was prevented by either progesterone or estrogen, while the combination of progesterone and estrogen had no effect on the bone mineral content. The present study suggests the possibility that estrogen-progestin treatment may be less effective than a therapy with estrogen alone, and that further study on the effect of progesterone alone would be worthwhile.

Postnatal development of the M-band in rat cardiac myofibrils.

Cardiac muscle fibers in rats at 1 and 5 days after birth showed little evidence of M-bands. An ultrastructural analysis of myofibrils failed to demonstrate dense M-band material in longitudinal sections or M-bridges in transverse sections of sarcomeres. M-bands began to increase in number after 5 days of postnatal life and were present in 60% of all sarcomeres at 11 days of age. Polypeptides with molecular weights of 190,000 (Ma) and 175,000 (Mb) were obtained by polyacrylamide-sodium dodecyl sulfate (SDS) gel electrophoresis of myofibril preparations. These two proteins were found in both 1- and 11-day-old rats and were considered to be specific components of the M-band. The densitometric analysis demonstrated that Ma and mb polypeptides increased approximately 2-fold during the interval from 1 to 11 days after birth. These structural and biochemical changes of the M-band material in myocytes appear to be related to the maturation of contractile function in the young heart.

Mercury, chromium, lead and organochlorine pesticide residues in some food products of animal origin: A review.

The authors present the results of several years' work in the field of food pollution. The research, which has been carried out on food products of animal origin marketed in the north of Italy, has established that the degree of contamination by heavy metals (mercury, chromium and lead) and organochlorine pesticides is generally lower than the tolerances suggested by the World Health Organisation.

Molecular weight distribution of soluble polypeptides from the 'Parma county ham' before, during and after maturation.

SDS polyacrylamide gel electrophoresis has been employed to study the molecular weight distribution of soluble polypeptides from the 'Parma county ham', a salted pork product. Limited proteolysis was observed, but this was mainly confined to the sarcoplasmic proteins. The results are discussed in the light of previous studies on the same type of products.