Characterization of the Ubiquitin-Modified Proteome of Recombinant Chinese Hamster Ovary Cells in Response to Endoplasmic Reticulum Stress.

Chinese hamster ovary (CHO) cells remain the most widely used host cell line for biotherapeutics production. Despite their widespread use, understanding endoplasmic reticulum (ER) stress conditions in recombinant protein production remains limited, often creating bottlenecks preventing improved production titers and product quality. Ubiquitination not only targets substrates (e.

LC-MS/MS Analysis to Study the Ubiquitin-Modified Proteome of Recombinant Chinese Hamster Ovary Cells.

Ubiquitination is one of the most important post-translational modifications (PTMs) and involves the covalent attachment of ubiquitin to a lysine residue on a target protein. Despite ubiquitination playing a crucial role in regulating cellular processes, the ubiquitinated proteome has not been studied extensively in recombinant Chinese hamster ovary (CHO) cells. Moreover, ubiquitination modification in CHO cells is likely to have an impact on protein function related to the efficient productivity of biopharmaceuticals.

Phosphopeptide Enrichment and LC-MS/MS Analysis to Study the Phosphoproteome of Recombinant Chinese Hamster Ovary Cells.

The reversible phosphorylation of proteins on serine, threonine, and tyrosine residues is one of the most important post-translational modifications that regulates many biological processes. There have been relatively few studies on the phosphoproteome of recombinant Chinese hamster ovary (CHO) cells to date despite phosphorylation playing a crucial role in regulating many molecular and cellular processes relevant to bioprocess phenotypes including, for example, transcription, translation, growth, apoptosis, and signal transduction. In this chapter, we provide a protocol for phosphoproteomic analysis of CHO cells using phosphopeptide enrichment with metal oxide affinity chromatography (MOAC) and immobilized metal affinity chromatography (IMAC) techniques, followed by site-specific identification of phosphorylated residues using liquid chromatography mass spectrometry (LC-MS), multistage activation (MSA), and MS3 strategies.

Using an insulating fiber as the sampling probe and ionization substrate for ambient ionization-mass spectrometric analysis of volatile, semi-volatile, and polar analytes.

A sharp metal needle used as the ionization emitter in conventional atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) is usually required for analyte ionization through corona discharge (i.e., gas discharge).

Functional magnetic nanoparticle-based affinity probe for MALDI mass spectrometric detection of ricin B.

The use of lactosylated FeO magnetic nanoparticles (MNP@LAC) has been explored as affinity probes against ricin B based on galactose-ricin B binding interactions. Lactose was bound onto the surface of aminated MNPs through the Maillard reaction. The enrichment of ricin B took ~1 h by incubating MNP@LAC with samples under shaking at room temperature, followed by magnetic isolation.

Using lactosylated cysteine functionalized gold nanoparticles as colorimetric sensing probes for rapid detection of the ricin B chain.

A new colorimetric method that can be used to rapidly detect toxic ricin is demonstrated. Lactosylated cysteine-functionalized gold nanoparticles (Au@LACY NPs) were prepared by a one-pot reaction and employed as optical probes for determination of ricin B chain. It is found that the Au@LACY NPs undergo aggregation in the presence of ricin B chain.

Tail Fiber Protein-Immobilized Magnetic Nanoparticle-Based Affinity Approaches for Detection of .

() strains are common nosocomial pathogens that can cause infections and can easily become resistant to antibiotics. Thus, analytical methods that can be used to rapidly identify from complex samples should be developed. Tail fiber proteins derived from the tail fibers of bacteriophages can recognize specific bacterial surface polysaccharides.

Functionalized gold nanoparticles as affinity nanoprobes for multiple lectins.

Glycan-lectin interactions are commonly observed in nature. Analytical methods, which are used to detect lectins that rely on the use of glycan ligand-modified nanoprobes as affinity probes, have been developed. Most of the existing methods are focused on the use of synthetic glycan ligands.

Selective Detection of Shiga-like Toxin 1 from Complex Samples Using Pigeon Ovalbumin Functionalized Gold Nanoparticles as Affinity Probes.

Escherichia coli O157:H7 is a foodborne pathogen. This bacterial strain can generate Shiga-like toxins (SLTs), which can cause serious sickness and even death. Thus, it is important to develop effective and sensitive methods that can be used to rapidly identify the presence of SLTs from complex samples.

Detection of ricin by using gold nanoclusters functionalized with chicken egg white proteins as sensing probes.

Ricin produced from the castor oil plant, Ricinus communis, is a well-known toxin. The toxin comprises A and B chains. Ricin A chain can cause toxicity by inhibiting protein synthesis, and ricin B can bind to the galactose ligand on the cell membrane of host cells.

Using protein-encapsulated gold nanoclusters as photoluminescent sensing probes for biomolecules.

In this study, we generated gold nanoclusters (AuNCs) using inexpensive chicken egg white proteins (AuNCs@ew) as reagents. AuNCs@ew were generated by reacting aqueous tetrachloroauric acid with diluted chicken egg white under microwave heating (90W) through subsequent heating cycles (5 min/cycle). Within 10 cycles, red photoluminescent AuNCs@ew with maximum emission wavelength at ~640 nm (λex=370 nm) were obtained.