Thomas Bucher

• ETH Zurich

Estrogens are released to the aquatic environment by wastewater treatment plant (WWTP) effluents and can affect wildlife. In the last three decades, many in vitro assay platforms were developed to detect and quantify estrogenicity in water. In 2018, ISO‐standardized protocols became available for three types of in vitro estrogen receptor transactiv...

Ecotoxicological screening of surface waters can involve multiple analyses using multiple bioassay and chemical analytical methods that require enriched samples to reach low concentrations. Such broad screening of the same sample necessitates sufficient sample volume—typically several liters—to produce a sufficient amount of enriched sample. Often,...

Endocrine-active substances can adversely impact the aquatic ecosystems. A special emphasis is laid, among others, on the effects of estrogens and estrogen mimicking compounds. Effect-based screening methods like in vitro bioassays are suitable tools to detect and quantify endocrine activities of known and unknown mixtures. This study describes th...

Digital PCR methods were recently introduced in food analysis. To run these methods within the scope of ISO17025, they have to be validated. Although several guidelines are available, each laboratory has to implement these guidelines in an adapted validation scheme. We present here one possible implementation. We chose 13 GMO traits which were pred...

According to the EU and Swiss food legislation, only authorised traits of transgene plants are allowed to be imported and sold to the consumer. In order to control imports of maize products from retailers, efficient and reliable methods for the detection and quantification are a prerequisite. Actually, in the EU, more than 25 gm Maize traits were a...

Due to its higher trade value, a broad range of adulterations of Basmati rice with cheaper rice varieties can be found on the market. A duplex digital droplet PCR (ddPCR) assay was developed to test rice samples, labeled as “Basmati,” for their authenticity. The new ddPCR assay is based on the real-time PCR (rtPCR) method published previously. It s...

New genetically modified (gm) soy crops are going to be released for human consumption. Therefore, analytical skills have to be developed towards an efficient detection and determination of GMO content in feed and food. Existing approaches to screen gm plants do not detect new gm soy traits in many cases. Therefore, a multiplex quantitative real-ti...

Digital PCR promises quantification of nucleic acids without using external standards. This new opportunity may relieve molecular analytics from an important source of discussions and measurement uncertainty. In addition, small numbers of samples might be quantified more efficiently. We established several digital PCR methods for the quantification...

Although linkage maps are important tools in evolutionary biology, their availability for wild populations is limited. The population of song sparrows (Melospiza melodia) on Mandarte Island, Canada, is among the more intensively studied wild animal populations. Its long-term pedigree data, together with extensive genetic sampling, have allowed the...

Abstract A ccording to the release of authorization, several new transgenic soy crops are expected to be present in the harvest of soy beans. In contrast to earlier times, methods for the detection of these transgenic crops are available already in advance. However, these methods are mainly still inefficient single real-time PCR methods. To increas...

Basmati rice has a higher trade value compared to other rice varieties. Adulterations of Basmati with cheaper varieties, sometimes in substantially amounts, are well known. To screen Basmati samples for such fraud, an efficient duplex real-time PCR assay was developed. It applies a mixed technique using hydrolysis probes in conjunction with Plexor™...

According to the EU and Swiss legislation, allergens in food have to be labelled. Consumers, exhibiting allergic reaction, must be able to avoid such food and its products. In order to provide efficient and reliable methods, two novel hexaplex quantitative real-time polymerase chain reaction systems were developed and validated. The first system si...

In the past, the transgenic soybean Roundup Ready was the predominantly cultivated transgenic soybean. With the announcement of Monsanto Corp. that this trait will be replaced by Mon89788 and the release of other company’s transgenic soy crops, this unique status of one trait has ended. Therefore, a multiplex quantitative real-time PCR system was d...

According to life-history theory age-dependent investments into reproduction are thought to co-vary with survival and growth of animals. In polygynous species, in which size is an important determinant of reproductive success, male reproduction via alternative mating tactics at young age are consequently expected to be the less frequent in species...

Heterozygosity-fitness correlations use molecular measures of heterozygosity as proxy estimates of individual inbreeding coefficients (f) to examine relationships between inbreeding and fitness traits. Heterozygosity-fitness correlations partly depend on the assumption that individual heterozygosity and f are strongly and negatively correlated. Alt...

Abstract Comprehensive, accurate paternity assignment is critical to answering numerous questions in evolutionary ecology. Yet, most studies of species with extra-pair paternity (EPP) fail to assign sires to all offspring. Common limitations include incomplete and biased sampling of offspring and males, particularly with respect to male location an...

Eighteen polymorphic microsatellite DNA loci were isolated in the Central European subspecies of the European Dipper (Cinclus cinclus aquaticus). The loci were tested for polymorphism using a test panel of 24 breeding birds. Numbers of alleles ranged from 2 to 21 per locus and expected heterozygosities varied between 0.47 and 0.83. Two loci (Cici10...

Nineteen di- and tetranucleotide and one trinucleotide microsatellite DNA markers were isolated from the Galápagos mockingbird (Mimus parvulus) and tested for cross-species amplification in the other three mockingbird species in the Galápagos. In addition, primers for two microsatellite loci previously developed for Mimus polyglottos were redesigne...

A total of 14 dinucleotide microsatellite loci were characterized in the snow vole (Chionomys nivalis). Allelic polymorphism across all loci and 28 individuals representing a single population in the Swiss Alps was high (mean = 10.1 alleles). No significant linkage disequilibrium between pairs of loci and no departure from Hardy-Weinberg equilibriu...