Cloning,sequencing and disruption of the ARG8 gene encoding acetylornithine aminotransferase in the petite-negative yeast Kluyveromyces lactis

A recombinant plasmid was isolated from a Kluyveromyces lactis genomic DNA library which complements a Saccharomyces cerevisiae arg8 mutant defective in the gene encoding acetylornithine aminotransferase. The complementation activity was found to reside within a 2.0 kb DNA fragment. Nucleotide sequence analysis revealed an open reading frame able to encode a 423-residue protein sharing 68·1% and 35·0% sequence identities with the products of the ARG8 and argD genes of S. cerevisiae and Escherichia coli. That the cloned gene, KlARG8, is the functional equivalent of S. cerevisiae ARG8 was supported by a gene disruption experiment which showed that K. lactis strains carrying a deleted chromosomal copy of KlARG8 are auxotrophic for arginine. The nucleotide sequence of KlARG8 has been submitted to GenBank under Accession Number U93209.     

Structural behavior of asymmetric spindle-shaped Tensairity girders under bending loads

The load bearing behavior of an asymmetric spindle shaped Tensairity girder is studied experimentally and compared to finite element analyses. The influence of the air pressure on the stiffness of the structure is investigated for homogeneous distributed load, asymmetric distributed load and a local load at the center of the structure. An overall good correlation between experiments and finite element predictions was found. An analytical model based on two coupled ordinary differential equations is presented and solved for the homogeneous distributed load case. The role of the form of the Tensairity girder on the stiffness is investigated by comparing the load-deflection behavior of the asymmetric spindle shaped girder with a cylindrical shaped girder.     

Lipoconjugates for the noncovalent generation of microarrays in biochemical and cellular assays

The generation of microarrays by functionalization of hydrophobic glass surfaces with conjugates of triacylated lipophilic end-groups and with a peptide or hapten as a test substance is presented. Immobilization on the hydrophobic surfaces through the triacylated anchor group is fully orthogonal to the reactivity of functional groups within the test substances. The technique is therefore free of risk that reactions of these functional groups may influence the biological activity of the test compounds in screening applications. In addition, no preactivation of either the surface or the compounds is required. Reagents and substrates may be stored at ambient conditions for long periods of time. The lipoconjugates are administered from aqueous solution enabling automated nanopipetting down to spot dimensions of 100 microm across. The microstructures are stable with respect to the conditions of biochemical assays and applications in cell biology. Due to the hydrophobicity of the nonfunctionalized surfaces, standard blocking protocols used in microtiter-plate testing can be employed, thereby inhibiting nonspecific binding of assay reagents. Generation of these microstructures on hydrophobic glass slides or coverslips enables highly sensitive multichannel read-outs with high-resolution fluorescence microscopy.     

利用有色矿物油测定洗涤剂的洗涤效率

叙述了测定洗涤剂效率的测试规范的开发.开发目的是给织物后整理商提供一种方法,使他们能通过在规定的条件下洗涤测出表面活性剂的效率.     

Metabolic Effect of Blocking Sodium-Taurocholate Co-Transporting Polypeptide in Hypercholesterolemic Humans with a Twelve-Week Course of Bulevirtide—An Exploratory Phase I Clinical Trial

Bile acids (BA) play an important role in cholesterol metabolism and possess further beneficial metabolic effects as signalling molecules. Blocking the hepatocellular uptake of BA via sodium-taurocholate co-transporting polypeptide (NTCP) with the first-in-class drug bulevirtide, we expected to observe a decrease in plasma LDL cholesterol. In this exploratory phase I clinical trial, volunteers with LDL cholesterol > 130 mg/dL but without overt atherosclerotic disease were included. Thirteen participants received bulevirtide 5 mg/d subcutaneously for 12 weeks. The primary aim was to estimate the change in LDL cholesterol after 12 weeks. Secondary endpoints included changes in total cholesterol, HDL cholesterol, lipoprotein(a), inflammatory biomarkers, and glucose after 12 weeks. In addition, cardiac magnetic resonance imaging (CMR) was performed at four time points. BA were measured as biomarkers of the inhibition of hepatocellular uptake. After 12 weeks, LDL cholesterol decreased not statistically significantly by 19.6 mg/dL [−41.8; 2.85] (Hodges–Lehmann estimator with 95% confidence interval). HDL cholesterol showed a significant increase by 5.5 mg/dL [1.00; 10.50]. Lipoprotein(a) decreased by 1.87 mg/dL [−7.65; 0]. Inflammatory biomarkers, glucose, and cardiac function were unchanged. Pre-dose total BA increased nearly five-fold (from 2026 nmol/L ± 2158 (mean ± SD) at baseline to 9922 nmol/L ± 7357 after 12 weeks of treatment). Bulevirtide was generally well tolerated, with most adverse events being administration site reactions. The exploratory nature of the trial with a limited number of participants allows the estimation of potential effects, which are crucial for future pharmacological research on bile acid metabolism in humans.     

A comparison of methods to quantify cationization of cellulosic pulps

Fibers resulting from pulping of wood are negatively charged by nature. This charge might be reversed by chemical modification for different applications. In this study, different options to determine the degree of substitution (DS) with cationic groups introduced using 2,3-epoxypropyltrimethylammonium chloride, a common cationization reagent, are compared. Classical analytical methods for this purpose include elemental analysis, which is unspecific, and titration, which is sensitive toward impurities and highly elaborate. These are complemented by fast and robust approaches based on infrared spectroscopy or thermogravimetric analysis. The absorption increase at 1480 cm^?1 is specific for the introduced R-NMe₃ and linearly correlated with the DS. For bleached Kraft pulps, cationization splits the thermal degradation of cellulose in two phases, their ratio being roughly proportional to the DS. Both methods require virtually no sample preparation. Infrared spectroscopy is particularly easy to apply and allows a quantification of pulp cationization in short time.