Reversible changes in dissolution of the zona pellucida of immature bovine oocytes.

The influence of holding immature bovine oocytes in in vitro bovine oviducts on the dissolution of zona pellucida in 0.1% pronase, the role of cumulus cells in this process and the possibility of reversing the process were examined. For the study, 1,045 oocytes were obtained from 2 to 6 mm ovarian follicles.

Twinning in thoroughbred mares in Poland.

Of the thoroughbred population bred in Poland from 1952 to 1976, an average of 3.3% twinnings were registered. Of these averages 73% resulted in abortion, 11% in still births, and 16% in the live birth of one or both of the foals.

Effect of dexamethasone and hydrocortisone on the course of superovulation in cattle.

The effect of hydrocortisone and dexamethasone on superovulation was examined in 12 cows. On the day PMSG was given, each animal received either the first of five daily doses of 250 mg succinate hydrocortisone or one injection of 30 mg dexamethasone. In the 48-hr interval between the injection of PMSG and PGF(2)alpha, the concentration of progesterone rose from 6.

Carotenoids in the outer cell-wall layer of Scenedesmus (Chlorophyceae).

Scenedesmus obliquus, strain 633, which synthesizes ketocarotenoids and sporopollenin, also forms pink-red-colored cell walls. Both the cell walls left over after autospore liberation and those from homogenates of disrupted green cells have similar carotenoid pigmentation. Canthaxanthin, astaxanthin, an unidentified ketocarotenoid, and lutein were found as integral cell wall components.