Ion exchange chromatography of biotherapeutics: Fundamental principles and advanced approaches.

Ion exchange chromatography (IEX) is an important analytical technique for the characterization of biotechnology-derived products, such as monoclonal antibodies (mAbs) and more recently, cell and gene therapy products such as messenger ribonucleic acid (mRNA) and adeno-associated viruses (AAVs). This review paper first outlines the basic principles and separation mechanisms of IEX for charge variant separation of biotherapeutics, and examines the different elution modes based on salt or pH gradients. It then highlights several recent trends when applying IEX for the characterization of biotechnology-derived products, including: i) the effective use of pH gradients, ii) the improvement of selectivity by using organic solvents in the mobile phase, multi-step gradients, or by combining ion pairing and ion exchange, and iii) the increase in analytical throughput using ultra-short columns or automated screening of conditions.

Emergence of power law distributions in protein-protein interaction networks through study bias.

Degree distributions in protein-protein interaction (PPI) networks are believed to follow a power law (PL). However, technical and study biases affect the experimental procedures for detecting PPIs. For instance, cancer-associated proteins have received disproportional attention.

Characterization of middle ear microbiome in otitis media with effusion in Hungarian children: may potentially hamper the microbial diversity.

Introduction: Although otitis media with effusion (OME) is a common cause of hearing impairment in children, little is known about its microbiological background. We aimed to analyse the microbiome of the middle ear fluid (MEF) in OME to identify microbiological, demographic and environmental factors that may potentially influence the middle ear microbiome. In addition, we aimed to compare the results of conventional culture techniques and PCR-based methods.

Determination of Rhythmicity and Gestational Stage-Related Distribution of Blood Plasma Melatonin Concentrations in Donkey Mares.

The aim of this study is to obtain a more complete picture of blood plasma melatonin concentrations in the donkey mares. To this purpose, sampling and statistical processing were carried out in such a way that allowed the researchers to establish the annual and daily rhythms. Based on human observations, according to the hypothesis of the authors, the blood plasma melatonin concentration of pregnant individuals rises during the late gestational period, before parturition.