Expression of the synthetic gene of an artificial DDT-binding polypeptide in Escherichia coli

This paper reports the expression of an artificial functional polypeptide in bacteria. The gene of a designed 24-residue DDT-binding polypeptide (DBP) was inserted between the BamHI and PstI cleavage sites of plasmid pUR291. The hybrid plasmid, pUR291-DBP, was cloned in Escherichia coli JM109. After induction by isopropyl-β-D-thiogalactopyranoside a fusion protein was expressed in which DBP was linked to the COOH-termiuus of β-galactosidase. DBP, which is stable to trypsin, was obtained by tryptic digestion of the fusion protein and subsequent fractionation of the tryptic peptides by reversed-phase h.p.l.c. Recombinant and chemically synthesized DBP showed identical chromatographic properties, amino acid composition, and chymotryptic digestion patterns. Both the β-galactosidase-DBP fusion and isolated recombinant DBP bound DDT. The fusion protein was 25 times as potent as the designed 24-residue DBP in activating a cytochrome P-450 model system using equimolar catalytic amounts of the two protein

A facile and green route to terpene derived acrylate and methacrylate monomers and simple free radical polymerisation to yield new renewable polymers and coatings

We present new acrylic monomers derived directly from abundant naturally available terpenes via a facile, green and catalytic approach. These monomers can be polymerised to create new polymers with a wide range of mechanical properties that positions them ideally for application across the commodity and specialty plastics landscape; from packaging, cosmetic and medical, through to composites and coatings. We demonstrate their utility through formation of novel renewable polymer coatings

Eine Analyse über die Integration von WhatsApp in den Auskunftsdienst von öffentlichen und wissenschaftlichen Bibliotheken in Deutschland

In dieser Arbeit werden unterschiedliche Social-Media-Konzepte in Bibliotheken vorge-stellt und ausgewählte Messenger-Dienste analysiert. WhatsApp wird genauer betrach-tet und als Bestandteil des Auskunftsdienstes in verschiedenen Bibliotheken untersucht. Des Weiteren wird eine andere Herangehensweise an die Erweiterung des Auskunfts-dienstes unter Einsatz eines Social-Media-Konzeptes vorgestellt

Laudatio 90 Jahre Volker ter Meulen – zum 19. Juni 2024

In einem 90-jährigen Leben gibt es viele Höhen und Tiefen, selbst in dem, was ich ein gewöhnliches Leben nennen würde. Aber unser heutiger Jubilar hat alles andere als ein normales Leben geführt. Aus dessen wahrhaft ungewöhnlichem Wirken möchte ich nur drei Facetten hervorheben, die ihn, so hoffe ich, in besonderem Maße charakterisieren, nämlich die Virologie, die Leopoldina und das Alter

Reprogramming the assembly of unmodified DNA with a small molecule

The ability of DNA to store and encode information arises from base pairing of the four-letter nucleobase code to form a double helix. Expanding this DNA ‘alphabet’ by synthetic incorporation of new bases can introduce new functionalities and enable the formation of novel nucleic acid structures. However, reprogramming the self-assembly of existing nucleobases presents an alternative route to expand the structural space and functionality of nucleic acids. Here we report the discovery that a small molecule, cyanuric acid, with three thymine-like faces reprogrammes the assembly of unmodified poly(adenine) (poly(A)) into stable, long and abundant fibres with a unique internal structure. Poly(A) DNA, RNA and peptide nucleic acid all form these assemblies. Our studies are consistent with the association of adenine and cyanuric acid units into a hexameric rosette, which brings together poly(A) triplexes with a subsequent cooperative polymerization. Fundamentally, this study shows that small hydrogen-bonding molecules can be used to induce the assembly of nucleic acids in water, which leads to new structures from inexpensive and readily available materials

Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking.

Topoisomerases catalyze changes in DNA topology by directing the movement of DNA strands through consecutive cleavage-rejoining reactions of the DNA backbone. We describe the use of a phenylselenyl-modified thymidine incorporated into a specific position of a partially unwound DNA substrate in crosslinking studies of Escherichia coli topoisomerase I to gain new insights into its catalytic mechanism. Crosslinking of the phenylselenyl-modified thymidine to the topoisomerase protein was achieved by the addition of a mild oxidant. Following nuclease and trypsin digestion, lysine residues on topoisomerase I crosslinked to the modified thymidine were identified by mass spectrometry. The crosslinked sites may correspond to proximal sites for the unwound DNA strand as it interacts with enzyme in the different stages of the catalytic cycle

Observation of the triplet metastable dtate of shallow donor pairs in AlN crystals with a negative-U behavior: A high-frequency EPR and ENDOR study

Theoretical predictions about the n-type conductivity in nitride semiconductors are discussed in the light of results of a high-frequency EPR an ENDOR study. It is shown that two types of effective-mass-like, shallow donors with a delocalized wave function exist in unintentionally doped AlN. The experiments demonstrate how the transformation from a shallow donor to a deep (DX) center takes place and how the deep DX center can be reconverted into a shallow donor forming a spin triplet and singlet states. © 2008 The American Physical Society

Ethical and legal assessment of genome editing in research on human cells

Neue molekularbiologische Methoden, die gezielte Eingriffe in das Erbgut erlauben, eröffnen vielversprechende Möglichkeiten in Forschung und Anwendung. Die unter den Begriffen Genome Editing und Genomchirurgie bekannten Verfahren machen jedoch auch eine gesamtgesellschaftliche Diskussion über ethische und rechtliche Fragen notwendig. Dies gilt insbesondere im Hinblick auf die Forschung an humanen Zellen. Die Forschung an menschlichen Embryonen ist in Deutschland durch das Embryonenschutzgesetz verboten. Das Gesetz, das 2011 zuletzt geändert wurde, deckt allerdings nicht alle Fragen ab, die die neuen Methoden der Genomchirurgie aufwerfen. Um die Diskussion zu diesem Themenkomplex in Deutschland zu fördern, hat eine interdisziplinär besetzte Expertengruppe der Nationalen Akademie der Wissenschaften Leopoldina das Diskussionspapier „Ethische und rechtliche Beurteilung des genome editing in der Forschung an humanen Zellen“ verfasst