Martin Luther University of Halle-Wittenberg

About: Martin Luther University of Halle-Wittenberg is a education organization based out in Halle, Germany. It is known for research contribution in the topics: Population & Liquid crystal. The organization has 20232 authors who have published 38773 publications receiving 965004 citations. The organization is also known as: MLU & University of Wittenberg.

Carbon nanotubes in liquid crystals

Abstract: We review the research on carbon nanotube (CNT) dispersion in liquid crystals (LCs), focusing mainly on the approaches where the aim is to align CNTs along the LC director field, but also covering briefly the proposed possibility to enhance thermotropic LCs by CNT doping All relevant LC types are considered: thermotropic LC hosts allowing dynamic CNT realignment, lyotropic LC hosts allowing very high concentration of CNTs uniformly aligned over macroscopic areas and consequent removal of the LC, and LC phases formed by CNTs themselves, used in spinning high-quality carbon nanotube fibres We also discuss the issue of CNT dispersion in some detail, since successful nanotube separation is imperative for success in this field regardless of the type of LC that is considered We end by defining a few major challenges for the development of the field over the next few years, critical for reaching the stage where industrially viable protocols for LC-based CNT alignment can be defined

Polysaccharide-based aerogels as drug carriers

Abstract: The application of aerogels as drug delivery system was successfully demonstrated for silica aerogels previously However, being biocompatible silica matrices are not biodegradable, which is a certain disadvantage for a number of pharmaceutically oriented applications For these purposes biodegradable materials are beneficial Supercritical drying of polysaccharide gels results in highly porous biodegradable aerogel matrices with large surface areas Structural properties of the polysaccharide aerogels depend on the preparation method and chemical nature of the gel phase In this work different polysaccharide precursors (starch, alginate) were used to produce aerogels, which later on were loaded with the drugs ibuprofen and paracetamol Furthermore release kinetics was studied in vitro Thereby it has been shown that the release rate depends primary on the properties of the matrix The presented results demonstrate for the first time the high potential of polysaccharide aerogels for pharmaceutical applications

The deadenylating nuclease (DAN) is involved in poly(A) tail removal during the meiotic maturation of Xenopus oocytes

Abstract: Exonucleolytic degradation of the poly(A) tail is often the first step in the decay of eukaryotic mRNAs and is also used to silence certain maternal mRNAs translationally during oocyte maturation and early embryonic development. We previously described the purification of a poly(A)‐specific 3′‐exoribonuclease (deadenylating nuclease, DAN) from mammalian tissue. Here, the isolation and functional characterization of cDNA clones encoding human DAN is reported. Recombinant DAN overexpressed in Escherichia coli has properties similar to those of the authentic protein. The amino acid sequence of DAN shows homology to the RNase D family of 3′‐exonucleases. DAN appears to be localized in both the nucleus and the cytoplasm. It is not stably associated with polysomes or ribosomal subunits. Xenopus oocytes contain nuclear and cytoplasmic DAN isoforms, both of which are closely related to the human DAN. Anti‐DAN antibody microinjected into oocytes inhibits default deadenylation during progesterone‐induced maturation. Ectopic expression of human DAN in enucleated oocytes rescues maturation‐specific deadenylation, indicating that amphibian and mammalian DANs are functionally equivalent.

Control of poly(A) tail length

Abstract: Poly(A) tails have long been known as stable 3' modifications of eukaryotic mRNAs, added during nuclear pre-mRNA processing. It is now appreciated that this modification is much more diverse: A whole new family of poly(A) polymerases has been discovered, and poly(A) tails occur as transient destabilizing additions to a wide range of different RNA substrates. We review the field from the perspective of poly(A) tail length. Length control is important because (1) poly(A) tail shortening from a defined starting point acts as a timer of mRNA stability, (2) changes in poly(A) tail length are used for the purpose of translational regulation, and (3) length may be the key feature distinguishing between the stabilizing poly(A) tails of mRNAs and the destabilizing oligo(A) tails of different unstable RNAs. The mechanism of length control during nuclear processing of pre-mRNAs is relatively well understood and is based on the changes in the processivity of poly(A) polymerase induced by two RNA-binding proteins. Developmentally regulated poly(A) tail extension also generates defined tails; however, although many of the proteins responsible are known, the reaction is not understood mechanistically. Finally, destabilizing oligoadenylation does not appear to have inherent length control. Rather, average tail length results from the balance between polyadenylation and deadenylation.