Adeno-associated viruses (AAV) are widely used viral vectors for in vivo gene therapy. The purification of AAV, particularly the separation of genome-containing from empty AAV capsids, is usually time-consuming and requires expensive equipment. In this study, we present a novel laboratory scale anion exchange flow-through polishing method designed to separate full and empty AAV.
View Article and Find Full Text PDFEukaryotic cells are thought to arrange nucleosomes into extended arrays with evenly spaced nucleosomes phased at genomic landmarks. Here we tested to what extent this stereotypic organization describes the nucleosome organization in Saccharomyces cerevisiae using Fiber-Seq, a long-read sequencing technique that maps entire nucleosome arrays on individual chromatin fibers in a high throughput manner. With each fiber coming from a different cell, Fiber-Seq uncovers cell-to-cell heterogeneity.
View Article and Find Full Text PDFAdeno-associated virus (AAV) vectors are among the most prominent viral vectors for gene therapy, and their investigation and development using high-throughput techniques have gained increasing interest. However, sample throughput remains a bottleneck in most analytical assays. In this study, we compared commonly used analytical methods for AAV genome titer, capsid titer, and transducing titer determination with advanced methods using AAV2, AAV5, and AAV8 as representative examples.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
September 2023
Antimicrobial peptides and proteins (AMPs) are promising alternatives to conventional antibiotics for the treatment of infections caused by multidrug-resistant bacteria. The production of recombinant AMPs is facilitated by platform technologies such as the C-tag, a sequence of four C-terminal amino acids that allows immunoaffinity capture and purification. However, the detection and quantification of such products throughout the manufacturing process is a significant challenge.
View Article and Find Full Text PDFThe production of antimicrobial peptides/proteins (AMPs) in sufficient quantities for clinical evaluation is challenging because complex peptides are unsuitable for chemical synthesis, natural sources have low yields, and heterologous systems often have low expression levels or require product-specific process adaptations. Here we describe the production of a complex AMP, the insect metalloproteinase inhibitor (IMPI), by adding a C-terminal C-tag to increase the yield compared to the unmodified peptide. We used a design of experiments approach for process intensification in Escherichia coli Rosetta-gami 2(DE3)pLysS cells and achieved a yield of 260 mg L, which is up to 30-fold higher than previously reported.
View Article and Find Full Text PDFSeveral chromatographic approaches have been established over the last decades for the production of pharmaceutically relevant viruses. Due to the large size of these products compared to other biopharmaceuticals, e.g.
View Article and Find Full Text PDFRecently, multimodal chromatography using restricted access media (RAM) for the purification of nanoparticles, such as viruses has regained increasing attention. These chromatography resins combine size exclusion on the particle shell and adsorptive interaction within the core. Accordingly, smaller process-related impurities, for example, DNA and proteins, can be retained, while larger product viruses can pass unhindered.
View Article and Find Full Text PDFThe Orf virus (ORFV) is a promising candidate for vector vaccines as well as for immunomodulatory and oncolytic therapies. However, few publications are available on its infectivity degradation or on suitable additives for prolonging its viral stability. In this study, the non-supplemented ORFV itself showed a very high stability at storage temperatures up to 28 °C, with a linear titer loss of 0.
View Article and Find Full Text PDFA promising new vaccine platform is based on the Orf virus, a viral vector of the genus Parapoxvirus, which is currently being tested in phase I clinical trials. The application as a vaccine platform mandates a well-characterised, robust, and efficient production process. To identify critical process parameters in the production process affecting the virus' infectivity, the Orf virus was subjected to forced degradation studies, including thermal, pH, chemical, and mechanical stress conditions.
View Article and Find Full Text PDFThe ability to stably maintain visual information over brief delays is central to healthy cognitive functioning, as is the ability to differentiate such internal representations from external inputs. One possible way to achieve both is via multiple concurrent mnemonic representations along the visual hierarchy that differ systematically from the representations of perceptual inputs. To test this possibility, we examine orientation representations along the visual hierarchy during perception and working memory.
View Article and Find Full Text PDFObjective: Alteplase is a recombinant tissue plasminogen activator used for thrombolytic treatment in several indications and is currently approved in Europe under the brand name Actilyse. The current manufacturing process for alteplase was recently modified to meet increasing global demands. The aim of this randomized, open-label, adaptive two-stage design, two-way crossover study was to establish bioequivalence of alteplase derived from the two manufacturing processes (modified versus current).
View Article and Find Full Text PDFKoi herpesvirus (KHV) is the causative agent of a koi herpesvirus disease (KHVD) inducing high mortality rates in common carp and koi (Cyprinus carpio). No widespread effective vaccination strategy has been implemented yet, which is partly due to side effects of the immunized fish. In this study, we present an evaluation of the purification of infectious KHV from host cell protein and DNA, using the steric exclusion chromatography.
View Article and Find Full Text PDFAccurate and rapid quantification of (infectious) virus titers is of paramount importance in the manufacture of viral vectors and vaccines. Reliable quantification data allow efficient process development at a laboratory scale and thorough process monitoring in later production. However, current gold standard applications, such as endpoint dilution assays, are cumbersome and do not provide true process analytical monitoring.
View Article and Find Full Text PDFFront Bioeng Biotechnol
March 2023
Adeno-associated virus (AAV) based vectors have recently been gaining importance as DNA delivery systems. Efficient downstream processing of AAV remains a major challenge as serotypes differ in physicochemical properties, making it difficult to design uniform purification processes. Clarification of AAV is an especially critical step.
View Article and Find Full Text PDFIn December 2019, the global coronavirus disease 2019 (COVID-19) pandemic began in Wuhan, China. COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which infects host cells primarily through the angiotensin-converting enzyme 2 (ACE2) receptor. In addition to ACE2, several studies have shown the importance of heparan sulfate (HS) on the host cell surface as a co-receptor for SARS-CoV-2-binding.
View Article and Find Full Text PDFDigestion with restriction enzymes is a classical approach for probing DNA accessibility in chromatin. It allows to monitor both the cut and the uncut fraction and thereby the determination of accessibility or occupancy (= 1 - accessibility) in absolute terms as the percentage of cut or uncut molecules, respectively, out of all molecules. The protocol presented here takes this classical approach to the genome-wide level.
View Article and Find Full Text PDFSteric exclusion chromatography (SXC) is a promising purification method for biological macromolecules such as the Orf virus (ORFV) vector. The method's principle is closely related to conventional polyethylene glycol (PEG) precipitation, repeatedly implementing membranes as porous chromatographic media. In the past decade, several purification tasks with SXC showed exceptionally high yields and a high impurity removal.
View Article and Find Full Text PDFObjective: To assess safety, tolerability, pharmacokinetics, and pharmacodynamics of treatment with the selective 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD1) inhibitor BI 187004 in male and female patients with type 2 diabetes and overweight or obesity.
Methods: Randomized, double-blind, parallel-group, placebo-controlled multiple rising dose study, with 10-360 mg BI 187004 once daily over 14 days in 71 patients. Assessments included 11beta-HSD1 inhibition in the liver and subcutaneous adipose tissue ex vivo (clinical trial registry number NCT01874483).
The vertical opacity structure of the martian atmosphere is important for understanding the distribution of ice (water and carbon dioxide) and dust. We present a new data set of extinction opacity profiles from the NOMAD/UVIS spectrometer aboard the ExoMars Trace Gas Orbiter, covering one and a half Mars Years (MY) including the MY 34 Global Dust Storm and several regional dust storms. We discuss specific mesospheric cloud features and compare with existing literature and a Mars Global Climate Model (MGCM) run with data assimilation.
View Article and Find Full Text PDFThe Feifer Assessment of Reading (FAR) is a comprehensive reading test for children ages 4 through 21 years. The FAR was designed to evaluate the underlying cognitive and linguistic processes of reading. It has 15 subtests to evaluate aspects of phonological development, orthographical processing, decoding, reading fluency, and comprehension skills.
View Article and Find Full Text PDFThe steric exclusion chromatography (SXC) is a rather new method for the purification of large biomolecules and biological nanoparticles based on the principles of precipitation. The mutual steric exclusion of a nonionic organic polymer, i.e.
View Article and Find Full Text PDFDespite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars' ubiquitous dust haze and to produce dust storms have not been well quantified in situ, with missions lacking either the necessary sensors or a sufficiently active aeolian environment. Perseverance rover's novel environmental sensors and Jezero crater's dusty environment remedy this. In Perseverance's first 216 sols, four convective vortices raised dust locally, while, on average, four passed the rover daily, over 25% of which were significantly dusty ("dust devils").
View Article and Find Full Text PDFIntroduction: Effective cell-based production processes of virus particles are the foundation for the global availability of classical vaccines, gene therapeutic vectors, and viral oncolytic treatments. Their production is subject to regulatory standards ensuring the safety and efficacy of the pharmaceutical product. Process analytics must be fast and reliable to provide an efficient process development and a robust process control during production.
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