Steroidogenesis in a case of hydatidiform mole

In a case of hydatidiform mole accompanied by theca lutein cysts there was a greatly increased urinary excretion of pregnanetriol. Incubation of the mole tissue with [4-14C]pregnenolone resulted in the formation of 17α-hydroxypregnenolone, progesterone, 16α-hydroxyprogesterone and 16βhydroxyprogesterone.

Cholesterol, pregnenolone, 17α-hydroxypregnenolone, pregnanediol, pregnanetriol and androstenedione were isolated from both the mole tissue itself and from the ovarian cyst fluid. Progesterone and 17α-hydroxyprogesterone were characterized only from the cyst fluid. Greater quantities of the metabolic intermediates between pregnenolone and pregnanetriol were isolated from the cyst fluid than from the mole tissue.

On the basis of these results it is concluded that although the mole tissue is active in steroid metabolism the increased urinary excretion of pregnanetriol is a function of the polycystic ovaries.

Biosynthesis of thiamine. Incorporation experiments with 14C-labelled substrates and with (15N)glycine in Saccharomyces cerevisiae

1. Yeast was grown in a minimal synthetic medium together with a range of (14)C-labelled substrates under standardized conditions. After isolation, the purified thiamine was cleaved by sulphite and the pyrimidine and thiazole moieties were purified and assayed for radioactivity. 2. In order of decreasing incorporation, [(14)C]formate, [3-(14)C]serine, [2-(14)C]glycine and [2-(14)C]acetate supplied label for the pyrimidine, and [2-(14)C]glycine, [3-(14)C]serine, [1-(14)C]glycine, [(14)C]formate and [2-(14)C]acetate for the thiazole. Incorporation of label into the fragments from several other (14)C-labelled substrates, including [Me-(14)C]- and [3,4-(14)C(2)]-methionine, was insignificant. 3. [3-(14)C]Serine was shown not to contribute label to C-2 of the thiazole ring. 4. Significant incorporation of nitrogen from [(15)N]glycine into the thiazole moiety, but not into the pyrimidine moiety, was established. 5. It appears that C-2 and N-3 of the thiazole ring are formed from C-2 and the nitrogen atom of glycine, but the entire methionine molecule does not appear to be implicated.

Rhipicephalus reichenowi Zumpt, 1943: a re-description of the male and female and descriptions of the nymph and larva, together with an account of its known hosts and distribution

The male and female of Rhipicephalus reichenowi are re-described and the nymph and larva are described for the first time. The affinities of the species within the genus are discussed.

Its developmental periods under laboratory conditions are given and all known records of its hosts and distribution in the field are noted.

The author wishes to thank the Director of the East African Veterinary Research Organization for permission to publish this paper. She is also most grateful to everyone who submitted field collections of this species to her and to Dr Hoogstraal for permission to quote unpublished information; to Dr G. Theiler for her helpful suggestions during the preparation of the manuscript, and to Mr G. M. Kohls, Dr C. M. Clifford and Dr H. Hoogstraal, who also checked the manuscript before publication.