Zur Genetik vonPetunia hybrida

Ohne ZusammenfassungTeil einer Dissertation, die bei der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Köln eingereicht wurde.     

Die Wuchsstoffe von Coleus,Cucumis und Helianthus

Ohne ZusammenfassungMit 1 Textabbildung.     

Elektromorphe phycochromoproteid-Muster: Eine taxonomische identifikationsmethode für Cyanobackterien-Species

The disc-gel electrophoretograms of aqueous crude extracts of organisms containing phycochromoproteins (Cyanobacteria, Rhodo- and Cryptophyta) give colored ‘fingerprints’, which are species specific and in many cases strain specific also (infraspecific variability). It was found that in a slightly acidic system (pH 4,3) the electrophoretograms in one single gel concentration (16% PAA) or the Hedrick-Smith plots for the phycochromoprotein bands represent a chemotaxonomic key for identification of Cyanobacteria species. The results summarized here in a list of chemotaxonomical and numerical data for 23 strains, allow one to distinguish between the size and charge isomers of the investigated biliproteids.     

Process characterization strategy for a precipitation step for host cell protein reduction

Process characterization using QbD approaches has rarely been described for precipitation steps used for impurity removal in biopharmaceutical processes. We propose a two-step approach for process characterization in which the first step focuses on product quality and the second focuses on process performance. This approach provides an efficient, streamlined strategy for the characterization of precipitation steps under the Quality by Design paradigm. This strategy is demonstrated by a case study for the characterization of a precipitation using sodium caprylate to reduce host cell proteins (HCP) during a monoclonal antibody purification process. Process parameters were methodically selected through a risk assessment based on prior development data and scientific knowledge described in the literature. The characterization studies used two multivariate blocks to decouple and distinguish the impact of product quality (e.g., measured HCP of the recovered product from the precipitation) and process performance (e.g., step yield). Robustness of the precipitation step was further demonstrated through linkage studies across the overall purification process. HCP levels could be robustly reduced to ≤100 ppm in the drug substance when the precipitation step operated within an operation space of ≤1% (m/v) sodium caprylate, pH 5.0–6.0, and filter flux ≤300 L/m²-hr for a load HCP concentration up to 19,000 ppm. This two-step approach for characterization of precipitation steps has several advantages, including tailoring of the experimental design and scale-down model to the intended purpose for each step, use of a manageable number of experiments without compromising scientific understanding, and limited time and material consumption.     

Do prions aggregate in response to electrical stimulation and does this play a role in long-term memory?

Prions are multi-stable proteins that can assume at least two stable conformations: a normal one that is detergent-soluble and is protease-sensitive, and a pathogenic one that is protease-resistant and that forms detergent-insoluble fibrillar aggregates. The fibrillar aggregates have been implicated in various neurodegenerative disorders. The normal biological function of prions is not known, yet the high conservation of the sequences of prions among distantly related animals strongly suggests a common and important function. There is now increasing evidence that prions, which are abundant in nervous tissue, may in fact be involved in memory retention. We propose that electrical activity at the synapse induces the surrounding prion molecules to aggregate. The aggregates serve to hold together the synaptic connection between neurons which are interacting at the instant the sensory stimulus is received. The set of neurons connected in this manner then form the neuronal circuit which is associated with the particular stimulus. We propose that the stronger the electrical activity, the greater will be the aggregations. Long-lasting memory will result from traumatic, or exciting, experiences. Further, the aggregations will be maintained, or reinforced, by repeated stimulation of the same set of neurons. Memory loss will occur when those aggregates dissolve.     

Using simple artificial intelligence methods for predicting amyloidogenesis in antibodies

Background  

All polypeptide backbones have the potential to form amyloid fibrils, which are associated with a number of degenerative disorders. However, the likelihood that amyloidosis would actually occur under physiological conditions depends largely on the amino acid composition of a protein. We explore using a naive Bayesian classifier and a weighted decision tree for predicting the amyloidogenicity of immunoglobulin sequences.