Effects of the preservation medium and storage duration of domestic cat ovaries on the maturational and developmental competence of oocytes in vitro

We examined the effectiveness of saline, Euro-Collins solution (EC), and ET-Kyoto solution (ET-K) as preservation media for the cold storage of feline ovaries. Ovaries were maintained in these media at 4°C for 24, 48, or 72 h until oocyte retrieval. The ET-K group exhibited a higher oocyte maturation rate than the saline group after 72 h of storage. Moreover, ET-K could sustain the competence of the feline oocytes to cleave after 48 h, and the morula formation rate of the ET-K group was higher than that of the other groups after 24 and 48 h. Furthermore, the ET-K group exhibited a higher blastocyst formation rate than the other groups after storage for 24 h, and only ET-K retained the developmental competence in blastocysts after 48 h of storage. In addition, regarding the cell numbers of the blastocysts, there was no significant difference among the tested groups. In conclusion, our results indicate that ET-K is a suitable preservation medium for feline ovaries.     

A PRELIMINARY INVESTIGATION OF THE PENETRATION AND TRANSLOCATION OF 2,4,5-T IN SOME TROPICAL TREES

Summary The relative mobility of ¹⁴C-labelled 2,4,5-T in the trunks of four different tree species was tested in dry and wet seasons, with the intention of observing the difference in translocation pattern between the susceptible ( Piptadeniastrum africanum, Celtis mildbraedii ) and the tolerant ( Xylopia quintasii, Ricinodendron heudelotii ) species, Nine trees were analysed altogether. There was a consistent pattern of adsorption and retention of the arboricide by the phloem of the four sensitive trees and downward movement of the material was marked, but in the five resistant trees the chemical was distributed upward to a greater extent in the transpiration stream. Thus in the susceptible species where there is more phloem movement the chcmical is least mobile, whereas in the tolerant ones where the chemical moves in the xylem, it is most mobile. Both types of investigation (longitudinal and radial) indicate that the killing action in the sensitive species is due to the retention of the chemical by the phloem, and that its failure to kill the tolerant trees is due to the upward movement in the transpiration stream via the xylem.     

lead contamination of GROUNDWATER in an INDUSTRIAL complex

The objectives of this study were to investigate Pb contamination of a shallow groundwater aquifer underneath an industrial complex and Pb chemical forms that may be found in the study area. Concentrations of Pb in the groundwater samples ranged between 0.04 to 1570.12 µg L^-1 (10^-9.4 to 10^-5.1 mole L^-1), with an average of 88.2 µg L^-1 (10^-6.4 mole L^-1). The results of analysis of variance showed that sampling locations had significantly (p <0.05) affected Pb concentrations in the groundwater samples. Contour map of Pb concentrations and Pb/Cl ratios indicated that Pb contamination of groundwater could be associated to the seepage of irrigation water, corrosion of buried metallic structure (largely of iron), and leachate from the industrial dust pile. Thermodynamic modeling approach was used to speciate total Pb concentrations in the groundwater samples. The results of these computations revealed that, in the very dilute groundwater (salinity < 1 parts per thousand, i.e., ppt), Pb²⁺ and Pb-OH complexes were the most significant chemical forms. Groundwater salinities between 1 to 5 ppt, Pb²⁺, Pb-OH, Pb-Cl, Pb-HCO₃, and Pb-SO₄ were present in appreciable concentrations, depending on their respective anionic concentrations. Over 80% of the total Pb in water was present in Pb-Cl complexes in groundwater samples with salinities >40 ppt. A comparison of the calculated activities of Pb²⁺ and the thermodynamic solubility isotherms of Pb minerals suggested that mineral Pb(OH)₂(c) was too soluble to precipitate in these water samples. The distribution trend in Pb²⁺ activities do not support equilibrium with Pb₃(PO₄)₂(c). Formation of PbCO₃(c) and Pb₂CO₃Cl₂(c) in the groundwater samples appeared to be the most logical option. From the foregoing, it was concluded that Pb-CO₃ minerals can limit Pb solubility in saline groundwaters.