Effects of bis(2-ethylhexyl) phthalate, γ-hexachlorocyclohexane, and 17β-estradiol on the fry stage of medaka (Oryzias latipes).
The effects of bis(2-ethylhexyl) phthalate (DEHP), γ-hexachlorocyclohexane (γ-HCH), and 17β-estradiol (E2) on the fry stage of medaka were investigated. The medaka fry were exposed to different concentrations (0.01, 0.1, 1, and 10μg/L) of these chemicals for 3 weeks after hatching. Then, mortality, body weight, sex ratio, and gonadosomatic index (GSI) of the matured fish (after 5 months) were measured. Mortality was increased significantly in the 10μg/L E2 group. Distortion of sex ratio was found in 1 and 10μg/L E2 groups. DEHP treated groups showed the GSI reduction only in male fish. All the γ-HCH and parts of the E2 treated groups showed the GSI reduction in both sexes. Exposure of DEHP, γ-HCH, and E2 during the fry stage affected normal maturation of medaka at the concentrations which had no impact on mortality or sex ratio.
Hazard evaluation of diisononyl phthalate and diisodecyl phthalate in a Japanese medaka multigenerational assay.
Reproductive and developmental effects of diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) were evaluated in a Japanese medaka (Oryzias latipes) multigeneration protocol. Each phthalate was administered via fish flake diets at a concentration of 20 microg/g (1 microg/g fish/day). Two controls were included, untreated and acetone carrier. The F(0) and F(1) generation adults were reared to sexual maturation and the test was ended prior to sexual maturation of the F(2) generation. Biochemical, individual, and population parameters were evaluated: testosterone metabolism, 7-ethoxyresorufin-o-deethylase (EROD) activity, survival, development, growth, gonadal-somatic index, histopathology, sex ratio, and fecundity. Male fish showed a two-fold induction of several testosterone metabolites in the DINP-treated group compared to the untreated control but not the acetone control. In a similar manner, in female fish only the DIDP-treated group expressed greater testosterone hydroxylase activity. There were neither sex- nor treatment-related differences in the results from the EROD assay. A statistically significant transient delay in red blood cell pigmentation was observed. The male-to-female ratio was consistent across treatments and the phenotypic and histological gender classifications were in agreement. Egg production was not significantly different among treatment groups. Neither phthalate elicited an effect on reproduction or development at various levels of biological organization.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.