The plasma membrane H(+)-ATPase from the biotrophic rust fungus Uromyces fabae: molecular characterization of the gene (PMA1) and functional expression of the enzyme in yeast.

To study the molecular basis of biotrophic nutrient uptake by plant parasitic rust fungi, the gene (Uf-PMA1) encoding the plasma membrane H(+)-ATPase from Uromyces fabae was isolated. Uf-PMA1 exists probably as a single gene. However, two nearly identical sequences were identified; the similarity apparently is due to two Uf-PMA1 alleles in the dikaryotic hyphae. Multiple Uf-PMA1 transcripts were observed during early rust development, and reduced amounts of a single Uf-PMA1 mRNA were observed in haustoria and rust-infected leaves. This is in contrast to elevated enzyme activity in haustoria compared to germinated spores (C. Struck, M. Hahn, and K. Mendgen. Fungal Genet. Biol. 20:30-35, 1996). Unexpectedly, the PMA1-encoded rust protein is more similar to H(+)-ATPases from plants (55% identity) than from ascomycetous fungi (36% identity). When the rust PMA1 cDNA was expressed in Saccharomyces cerevisiae, both the wild-type enzyme and a mutant derivative (delta 76) deleted for the 76 C-terminal amino acids were able to support growth of a yeast strain lacking its own H(+)-ATPases. Compared to the wild-type, the delta 76 mutant enzyme displayed increased affinity to ATP, a higher vanadate sensitivity, and a more alkaline pH optimum. These results indicate that the C-terminal region of the rust enzyme exhibits auto-regulatory properties.

[Histological changes in the adrenal cortex of the Syrian hamster following perinatal treatment with sex steroids]. / Histologische Veranderungen der Nebennierenrinde des Syrischen Goldhamsters nach perinatal begonnerner Sexual-steroidbehandlung.

The adrenal cortex of the Syrian golden hamster is influenced by androgen hormone, for during puberty sex dimorphism of the adrenal cortex can be observed; it is prevented by perinatal castration. The following study will show, if and how other steroids influence the adrenal cortex of the normal and castrated female and male golden hamster. Beginning perinatally, groups of 10 hamsters each (intact and castrated males and females, altogether 160 animals) received testosterone hexohydrobenzoate (T), oestrogen undecylate (0), cyproterone acetate (CA) or sesame oil till the 6th week of life in an increasing, from the 6th-12th week in a constant dose. (T: 2.0 mg, 0: 1.0 mg, CA: 10.0 mg/week). The animals were sacrificed at the end of the 12th week of life. Control of adrenal weight; light microscopy of the adrenals; histometry, statistical evaluation of all data, and histochemistry. The adrenals of intact and castrated animals reacted in the same way. Under T treatment, in females, the zona reticularis enlarged as in males. By light microscopy and histometry there were no differences anymore between the female and male adrenals. 0 feminized the adrenal of the male, i.e. the zona reticularis became narrow with small cells, while the adrenal cortex of the female did not change. In both sexes, CA affected the zona reticularis less than the zona fasciculata. Thereby numeric and single cell atrophy was caused. Our results demonstrate the sex-specificity of the zona reticularis, showing a contrary influence by T and 0, and the rather glucocorticoid than anti-androgen-like effect by CA upon the adrenals.