Light is one crucial environmental signal which can determine whether a fungus reproduces asexually or initiates sexual development. Mating in the ascomycete Hypocrea jecorina (anamorph Trichoderma reesei) occurs preferentially in light. We therefore investigated the relevance of the light response machinery for sexual development in H. jecorina. We found that the photoreceptors BLR1 and BLR2 a...

Although the clinical aspects of Pneumocystis carinii pneumonia are well characterized, the basic biology of the causative organism is poorly understood. Most proposed life cycles of P. carinii include both asexual and sexual replicative cycles. The two most prominent morphological forms are a trophic form, thought to undergo asexual replication by binary fission, and a cystic form or ascus con...

Reproductive success in many animals depends on the efficient production of and response to sexual signals. In insects, plasticity in sexual communication is predicted in species that experience periods of reproductive inactivity when environmental conditions are unsuitable for reproduction. Here, we study a long-lived moth Caloptilia fraxinella (Ely) (Lepidoptera: Gracillariidae) that is repro...

Aspergillus fumigatus is a medically important opportunistic pathogen and a major cause of respiratory allergy. The species has long been considered an asexual organism. However, genome analysis has revealed the presence of genes associated with sexual reproduction, including a MAT-2 high-mobility group mating-type gene and genes for pheromone production and detection (Galagan et al., personal ...

Variability within sex pheromone signalling systems is generally believed to be low because of strong stabilizing selection; yet the noctuid moth Heliothis subflexa (Hs) shows significant intraspecific variation. One possible explanation is that females may alter their sex pheromone blend depending on prevailing olfactory cues in the habitat, which we termed the 'experience hypothesis'. This co...

Three recent studies report on the olfactory mechanisms used for gender identification in Drosophila and on the olfactory receptors stimulated by the pheromone 11-cis-vaccenyl acetate. This pheromone activates specific olfactory receptors that suppress the courtship of males with other males, promote the sexual receptivity of females, and participate in the formation of memories about prior cou...

Modes of sexual reproduction in eukaryotic organisms are extremely diverse. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally- and morphologically-differentiated white and opaque cells show a coordinated behavior during mating. Although white cells are mating...

Recently, sexual development in the heterothallic ascomycete Trichoderma reesei (anamorph of Hypocrea jecorina) has been achieved and thus initiated attempts to elucidate regulation and determinants of this process. While the α-type pheromone of this fungus fits the consensus known from other fungi, the assumed a-type peptide pheromone precursor shows remarkably unusual characteristics: it comp...

Many aspects of social behavior are controlled by sex-specific pheromones. Gender-appropriate production of the sexually dimorphic transcription factors doublesex and fruitless controls sexual differentiation and sexual behavior. miR-124 mutant males exhibited increased male-male courtship and reduced reproductive success with females. Females showed a strong preference for wild-type males over...

Vertebrates indicate their genetic sex to conspecifics using secondary sexual signals, and signal expression is often activated by sex hormones. Among vertebrate signaling modalities, the least is known about how hormones influence chemical signaling. Our study species, the red-sided garter snake (Thamnophis sirtalis parietalis), is a model vertebrate for studying hormonal control of chemical s...