The great screen anomaly—a new frontier in product discovery through functional metagenomics

Functional metagenomics, the study of the collective genome of a microbial community by expressing it in a foreign host, is an emerging field in biotechnology. Over the past years, the possibility of novel product discovery through metagenomics has developed rapidly. Thus, metagenomics has been heralded as a promising mining strategy of resources for the biotechnological and pharmaceutical industry. However, in spite of innovative work in the field of functional genomics in recent years, yields from function-based metagenomics studies still fall short of producing significant amounts of new products that are valuable for biotechnological processes. Thus, a new set of strategies is required with respect to fostering gene expression in comparison to the traditional work. These new strategies should address a major issue, that is, how to successfully express a set of unknown genes of unknown origin in a foreign host in high throughput. This article is an opinionating review of functional metagenomic screening of natural microbial communities, with a focus on the optimization of new product discovery. It first summarizes current major bottlenecks in functional metagenomics and then provides an overview of the general metagenomic assessment strategies, with a focus on the challenges that are met in the screening for, and selection of, target genes in metagenomic libraries. To identify possible screening limitations, strategies to achieve optimal gene expression are reviewed, examining the molecular events all the way from the transcription level through to the secretion of the target gene product

MICROWAVE STARK AND DOUBLE RESONANCE SPECTRA OF NITROETHANE

Author Institution: Physical Chemistry Laboratory ETHNitroethane contains two internal rotors, a nitro group with a low two-fold barrier and a methyl group with a high three-fold barrier. Its microwave spectrum has been investigated in the 7-40 GHz region. Both conventional Stark spectra as well as microwave-microwave double resonance sepctra have been used to assign relevant parts of the observed spectrum. The general characteristies are typical for a nearly free internal rotor. Calculated predictions from a semi-rigid model have been found to be compatible with a very low barrier value ($< 10$ $cm^{-1}$) for the internal rotation of the nitro group

STARK EFFECT IN ACETALDEHYDE: RELATIVE SIGN OF DIPOLE COMPONENTS

Author Institution: Laboratory for Physical Chemistry, ETH, Universit\""{a}tstrAccurate expectation values of the electric dipole operator for molecules with a symmetric internal rotor have been calculated using a semirigid model. Whereas the contributions from dipole components along the principal axes are completely separated for a rigid rotor, they are mixed appreciably for molecules with resolved internal rotation splittings. Combinations with different relative signs of the dipole components lead to different expectation values. This is demonstrated for acetaldehyde $(CH_{3}CHO)$ through the effect on the Stark splittings. Several transitions including excited torsional states have been analyzed and the relative signs of the dipole components have been determined

Building materials and construction:Constructing a quality of life

\u3cp\u3eCatastrophes and new societal ambitions energized the huge construction effort undertaken between 1910 and 1970. The floods of 1917 and 1953 led to enormous investments in coastal defences. The government also undertook major investments in the construction of roadways and other infrastructural works. New building codes, damage incurred during the Second World War and population growth incited new housing construction on a colossal scale. Demand for building materials grew apace. The need for wood and mineral subsoil resources transformed nature and landscapes in the Netherlands and at foreign sites. Dutch forestry practices were rationalised. Imports from the Baltic regions by and large met the Dutch demand for wood. But the creation of monocultures and production forests in these regions reduced local biodiversity. Gravel and marl were mined above all in the province of Limburg. That led to tensions with local stakeholders. Gravel extraction transformed the floodplains of the Meuse into a lake landscape. It led directly to the Excavation Law, the first environmental law in the area of land-use. After 1970, regulations concerning land-use and new landscape values would regularly inspire conflicts in the national supply of building materials (see Chap. 19).\u3c/p\u3