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Klemmer, D.

Publications and source records attributed to Klemmer, D..

2 recordsLinked to original sources

Universal Study Design for Instrument Changes in Pharmaceutical Release Analytics

Instrument changes in analytical methods of pharmaceutical quality control are required to maintain release analytics over decades, yet typically pose a challenge. We designed an efficient instrument comparability study to gain a comprehensive understanding of potential performance differences between instruments and therefore rationalize the risk assessment and decision process for a path forward. The results may either point out whether a full or partial re-validation is necessary or whether a science-based bridging can be pursued based on the data generated in the study. The study design is universally applicable to a substantial range of release analytical methods. In a straightforward setup of two experiments with the new instrument, a statistically meaningful data set is generated for comparison with available historical or validation data of the original instrument. In a Good Manufacturing Practice (GMP) environment, we realized the study design a first benchmark in imaged capillary isoelectric focusing (icIEF) analytics, comparing the ICE3 and Maurice C instruments. The core-study confirmed equal or better performance of Maurice C in all parameters and serves as a basis for seamless continuation of release measurements on Maurice C.

biochemistry↗

Survival of the simplest: the cost of complexity in microbial evolution

The evolution of microbial and viral organisms often generates clonal interference, a mode of competition between genetic clades within a population. In this paper, we show that interference strongly constrains the genetic and phenotypic complexity of evolving systems. Our analysis uses biophysically grounded evolutionary models for an organisms quantitative molecular phenotypes, such as fold stability and enzymatic activity of genes. We find a generic mode of asexual evolution called phenotypic interference with strong implications for systems biology: it couples the stability and function of individual genes to the populations global speed of evolution. This mode occurs over a wide range of evolutionary parameters appropriate for microbial populations. It generates selection against genome complexity, because the fitness cost of mutations increases faster than linearly with the number of genes. Recombination can generate a distinct mode of sexual evolution that eliminates the superlinear cost. We show that positive selection can drive a transition from asexual to facultative sexual evolution, providing a specific, biophysically grounded scenario for the evolution of sex. In a broader context, our analysis suggests that the systems biology of microbial organisms is strongly intertwined with their mode of evolution.

evolutionary biology↗