Author's personal copy Colloidal interactions between monoclonal antibodies in aqueous solutions

a b s t r a c t Colloidal interactions between proteins determine the behavior and stability of globular proteins such as monoclonal antibodies (mAbs) against their propensity to cluster formation in solution. We study interactions between these proteins through their dilute solution behavior. Experiments to quantify intermolecular interactions were done using Dynamic and Static Light Scattering (DLS and SLS) in a high-throughput manner in parallel with zeta potential measurements with Laser Doppler Electrophoresis method (M3-PALS). This approach offers a rapid indirect determination of colloidal interactions through their measured second virial coefficient. Electrostatic part of the DLVO interaction was conveniently parameterized via the corresponding surface charge and/or surface potential, while the van der Waals interactions were parameterized via their Hamaker coefficient, both as functions of ionic strength and pH of the bathing solution. This parametrization of protein-protein interactions improves our understanding of mAb assembly and provides a means for its control by solution parameter variation. Additionally, our results also provide a consistency check and validation of applicability of the DLVO theory in mAbs solution assembly processes

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus aureus </it>is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs.</p> <p>Results</p> <p><it>S. aureus </it>ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. <it>S. aureus </it>GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed.</p> <p>Conclusions</p> <p>Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.</p

The Sterolgene v0 cDNA microarray: a systemic approach to studies of cholesterol homeostasis and drug metabolism

<p>Abstract</p> <p>Background</p> <p>Cholesterol homeostasis and xenobiotic metabolism are complex biological processes, which are difficult to study with traditional methods. Deciphering complex regulation and response of these two processes to different factors is crucial also for understanding of disease development. Systems biology tools as are microarrays can importantly contribute to this knowledge and can also discover novel interactions between the two processes.</p> <p>Results</p> <p>We have developed a low density Sterolgene v0 cDNA microarray dedicated to studies of cholesterol homeostasis and drug metabolism in the mouse. To illustrate its performance, we have analyzed mouse liver samples from studies focused on regulation of cholesterol homeostasis and drug metabolism by diet, drugs and inflammation. We observed down-regulation of cholesterol biosynthesis during fasting and high-cholesterol diet and subsequent up-regulation by inflammation. Drug metabolism was down-regulated by fasting and inflammation, but up-regulated by phenobarbital treatment and high-cholesterol diet. Additionally, the performance of the Sterolgene v0 was compared to the two commercial high density microarray platforms: the Agilent cDNA (G4104A) and the Affymetrix MOE430A GeneChip. We hybridized identical RNA samples to the commercial microarrays and showed that the performance of Sterolgene is comparable to commercial arrays in terms of detection of changes in cholesterol homeostasis and drug metabolism.</p> <p>Conclusion</p> <p>Using the Sterolgene v0 microarray we were able to detect important changes in cholesterol homeostasis and drug metabolism caused by diet, drugs and inflammation. Together with its next generations the Sterolgene microarrays represent original and dedicated tools enabling focused and cost effective studies of cholesterol homeostasis and drug metabolism. These microarrays have the potential of being further developed into screening or diagnostic tools.</p

WHEAT AS A SOURCE OF RAW MATERIAL IN PASTE FOODS PRODUCTION ON TERRITORY OF VOJVODINA AUTONOMOUS PROVINCE

Importance of this research is to realize real production of wheat as a basic element for paste foods production in last period and paste foods consumption in VAP. Such analysis helps us see market investiture and possibility of penetration in it. Market its self becomes more selectively and turbulent. However, there is no only present competition among the producers who produce the same products or give the same services, but also is present so-called generic competition among the products and services which satisfy the same needs of consumers. Such competition could be prevented by detailed analysis of the market and it enables absolute long-term business. In order to realize changes in consumption, certain occurrences were compared with earlier periods. Gathered data were presented by graphs and tables and processed with standard mathematics and statistical methods

Management consulting as a factor in transfer of good practices for managerial know-how

Transition process and Serbia's entering into the European Union is possible to hasten by adequate and timely consulting services, before all during the programs and methodologies creation for conducting the enterprises' restructuring processes. In such conditions, the consultative organizations help the enterprises in accomplishing their goals, solving problems in business and management, identifying and using new possibilities, increasing their knowledge and applying suggested changes in the practice. The consulting represents a specific activity of helping the companies' managers to solve the problems in business for which they have no enough expertness, knowledge and experiences. In modern market economies, and especially those in which aspire to build the market mechanisms, the consulting is a result of a need for adequate and timely information, as a key factor of business success Necessity of overall transformation requires knowing the specific activities and interventions, which are a catalyst of building the efficient companies of market economy

WHEAT AS A SOURCE OF RAW MATERIAL IN PASTE FOODS PRODUCTION ON TERRITORY OF VOJVODINA AUTONOMOUS PROVINCE

Importance of this research is to realize real production of wheat as a basic element for paste foods production in last period and paste foods consumption in VAP. Such analysis helps us see market investiture and possibility of penetration in it. Market its self becomes more selectively and turbulent. However, there is no only present competition among the producers who produce the same products or give the same services, but also is present so-called generic competition among the products and services which satisfy the same needs of consumers. Such competition could be prevented by detailed analysis of the market and it enables absolute long-term business. In order to realize changes in consumption, certain occurrences were compared with earlier periods. Gathered data were presented by graphs and tables and processed with standard mathematics and statistical methods

Real-Time Assessment of the Size Changes of Individual Sub-Visible Protein Particles under Buffer Variations: A Microfluidic Study.

Protein particles in biological drugs can significantly impact drug efficacy and carry the risk of adverse effects. Despite advancements, the understanding and control of particle formation in biopharmaceutical manufacturing remain incomplete. Therefore, further investigation into protein particles is warranted, especially considering that novel formats of biological drugs may be more susceptible to aggregation and particle formation than conventional monoclonal antibodies. In this study, we introduce a microfluidic approach for the real-time analysis of individual sub-visible protein particles during buffer exchange. We find that the modulation of intermolecular forces, achieved by changing the buffer pH or urea concentration, leads to the reversible swelling and shrinkage of particles by up to 50%, which is a consequence of altered intermolecular distances. Additionally, we identify a discrepancy in the biophysical behavior of protein particles compared to monomeric protein. This finding highlights the limited predictive power of commonly applied biophysical characterization methods for particle formation in early formulation development. Moreover, the observed particle swelling may be associated with manufacturing deviations, such as filter clogging. These results highlight the importance of studying individual particles to gain a comprehensive insight into particle behavior and the impact of formulation variations in the biopharmaceutical industry