Abstract: The invention relates to a method for verifying and/or identifying hormonally effective substances using the pheromone system of yeast, to yeast cells for carrying out the method, and to the use thereof. The method according to the invention comprises the following steps: a) adding yeast culture medium or buffer to a sample which presumably contains a hormonally effective substance, b) thereafter contacting the sample with haploid yeast cells that possess features 1 through 3: 1. the DNA sequence coded for a heterologous hormone receptor is placed under the control of a constitutive promoter, 2. the DNA sequence coded for a yeast pheromone is placed under the control of a promoter that can be regulated by the hormone receptor, 3.

Abstract: The invention relates to a device and a method for the detection and amplification of a primary signal, utilizing an intracellular communication system, and the use thereof for the detection of substances such as phosphorus, sulfur, nitrogen, hormones, metabolic intermediates, fermentation products, and so forth. The device according to the invention for the detection and amplification of a primary signal contains cells of a first type for which a gene, which is responsible for the synthesis of a signal molecule, is under the control of a promoter which is regulated by the primary signal, and cells of a second type for which a specific gene is under the control of a promoter which is regulated by the separated signal molecule, in such a way that the secretion of the signal molecule is induced by a primary signal taken up by a cell of the first type, and the primary signal is amplified by the cells of the second type by the expression of the specific gene under the control of the signal molecule.

Abstract: The invention relates to whole-cell sensors for monitoring bioavailable nitrogen, phosphorus and sulphur, individually or in at least one combination in a medium, and to the use thereof. The whole-cell sensors consist of genetically modified yeast cells which are immobilised in a xerogel matrix and contain at least one marker gene controlled by a promoter of a gene, the transcription of said gene being significantly increased or reduced in the absence of nitrogen, phosphorus or sulphur, and the yeast cells are at least coupled to a signal detector.