Inhibition by estrogens of conidium-to-yeast conversion in the fungus Paracoccidioides brasiliensis

Abstract

Conidia produced by Paracoccidioides brasiliensis are inhibited by mammalian estrogens in their in vitro conversion into yeast-form cells. This was demonstrated with four different isolates. In these experiments, conversion was reduced to 10.7 and 34.4% of the control values by 17-beta-estradiol at 10-6 and l0-8 M, respectively. At the same concentrations, the synthetic estrogen diethylstilbestrol was slightly less inhibitory. In contrast, other sex hormones and analogs, i.e., testosterone, 17-alpha-estradiol, tamoxifen, and hydroxytamoxifen, had no effect on conidium-to-yeast conversion. Previous studies have shown that estrogens similarly inhibit mycelium-to-yeast-form transition in P. brasilensis. Conidia, and not mycelial fragments, are believed to be the natural infectious propagules. These findings with conidia support the hypothesis that estrogens, affecting the initial host-parasite interactions by suppressing conversion to the parasitic form of the organism, are, at least in part, responsible for the greater resistance of females to paracoccidioidomycosis.

Effect of Mammalian Steroid Hormones and Luteinizing Hormone on the Germination of Candida albicans and Implications for Vaginal Candidosis./;Die Wirkung von Säugersteroidhormonen und Gelbkörperreifungshormon auf die Keimschlauchbildung von Candida albicans und ihre Bedeutung für die Vaginalcandidose

“…For example, 17-P-oestradiol inhibits the mycelial to yeast transformation in l? brusiliensis at 10-6-10'8 M and at M in some strains (17,25,26). The transformation from mycelial to yeast growth occurs in the lungs in the initial establishment of infection and the authors suggest that the inhibition by oestrogens may explain the increased male susceptibility to this disease.…”

“…Oestradiol inhibits the conversion of the non-pathogenic mycelial form of the yeast Paracoccidiodes brasiliensis to the pathogenic yeast form (17,25,26) and 17P-oestradio1, progesterone and testosterone stimulate the maturation of parasitic endospores in Coccidiodes immitis (6). Also C. albicans has binding proteins for corticosterone, progesterone and oestradiol (4,14,15,16,25).…”

Linking fungal morphogenesis with virulence

“…In vitro studies demonstrated that 17‐β‐oestradiol inhibited the transition of P. brasiliensis mycelia or conidia to yeast. Progesterone, oestriol or the synthetic oestrogen diethylstilbestrol (DES) had less of an effect on the transition, while other hormones and hormone analogues such as testosterone, 17‐α‐oestradiol and tamoxifen had no effect (Salazar et al , 1988). Corollary studies of infection of male and female mice gave similar results.…”

Análise da capacidade migratória e da ativação de linfócitos T CD4+ por células dendríticas na paracoccidioidomicose expeimental

“…OBJETIVOS ....................................................................................................... 29 3. MATERIAL E MÉTODOS .................................................................................. ........................................................................................... (LOOSE et al, 1983;RESTREPO et al, 1984;SALAZAR et al, 1988e CLEMONS et al, 1989 BRUMMER et al, 1993).…”