Publications by authors named "Xuezhi Bi"

Sodium butyrate (NaBu), well-known as a histone deacetylase inhibitor and for its capacity to impede cell growth, can enhance the production of a specific protein, such as an antibody, in recombinant Chinese hamster ovary (CHO) cell cultures. In this study, two CHO cell lines, namely K1 and DG44, along with their corresponding mAb-producing lines, K1-Pr and DG44-Pr, were cultivated with or without NaBu. A SWATH-based profiling method was employed to analyze the proteome.

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, the most frequently isolated fungal pathogen in humans, forms biofilms that enhance resistance to antifungal drugs and host immunity, leading to frequent treatment failure. Understanding the molecular mechanisms governing biofilm formation is crucial for developing anti-biofilm therapies. In this study, we conducted a genetic screen to identify novel genes that regulate biofilm formation in .

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Potassium ions (K) released from dying necrotic tumour cells accumulate in the tumour microenvironment (TME) and increase the local K concentration to 50 mM (high-[K]). Here, we demonstrate that high-[K] decreases expression of the T-cell receptor subunits CD3ε and CD3ζ and co-stimulatory receptor CD28 and thereby dysregulates intracellular signal transduction cascades. High-[K] also alters the metabolic profiles of T-cells, limiting the metabolism of glucose and glutamine, consistent with functional exhaustion.

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This study demonstrated a comprehensive workflow combining in silico screening and prediction with in vitro validation to investigate the bioactivity of hempseed protein isolate (HPI) extracted and dehydrated using different methods. By adopting an in silico approach, 13 major proteins of HPI were hydrolysed by 20 selected enzymes, leading to the prediction of 20 potential bioactivities. With papain hydrolysis, dipeptidyl peptidase-IV (DPP4) and angiotensin-converting enzyme (ACE) inhibitory activities emerged as having the highest potential.

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Appended bispecific antibody (aBsAb) with two single chain variable fragments (scFv) linked at the c-terminus of its heavy chains is one of the promising formats in bispecific therapeutics. The presence of hydrophobic and flexible scFv fragments render aBsAb molecules higher molecule hydrophobicity and structural flexibility compared to monoclonal antibody (mAb), thus making its purification more challenging. We set out to investigate how the unique molecular properties of aBsAb affect its performance on Protein A chromatography.

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The gene therapy field seeks cost-effective, large-scale production of recombinant adeno-associated virus (rAAV) vectors for high-dosage therapeutic applications. Although strategies like suspension cell culture and transfection optimization have shown moderate success, challenges persist for large-scale applications. To unravel molecular and cellular mechanisms influencing rAAV production, we conducted an SWATH-MS proteomic analysis of HEK293T cells transfected using standard, sub-optimal, and optimal conditions.

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Article Synopsis
  • Bispecific antibodies (bsAbs) are a promising treatment option but present challenges in purification due to their complex structures and impurities.
  • Ceramic hydroxyapatite (CHT) is a mixed-mode medium that enhances protein purification by allowing different binding interactions, potentially yielding higher purity levels compared to traditional methods like cation exchange chromatography (CEX).
  • The study found that using CHT for bsAb purification achieved over 97% product purity, reduced high molecular weight impurities significantly, and minimized chromatography-induced aggregation, suggesting CHT's effectiveness varies based on the bsAb's characteristics.
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In the human fungal pathogen Candida albicans, invasive hyphal growth is a well-recognized virulence trait. We employed transposon-mediated genome-wide mutagenesis, revealing that inactivating CTM1 blocks hyphal growth. CTM1 encodes a lysine (K) methyltransferase, which trimethylates cytochrome c (Cyc1) at K79.

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Article Synopsis
  • - The study focuses on 2-phenylethanol (2-PE), a compound with a rose-like scent that can inhibit the growth of microbes, particularly affecting the performance of those used in its production.
  • - Bacillus licheniformis demonstrates a strong tolerance to 2-PE, and researchers used multi-omics technology to explore how this microbe manages 2-PE stress through antioxidant activation, metabolic pathway adjustments, and altering cell structure.
  • - Findings from the study reveal potential genetic targets to enhance 2-PE resistance, emphasizing the importance of tolerance to organic solvents for effective microbial production of valuable compounds like 2-PE.
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Background: The floc is a characteristic of microbial aggregate growth, displaying cloudy suspensions in water. Floc formation has been demonstrated in a series of bacteria and the floc-forming bacteria play a crucial role in activated sludge (AS) process widely used for municipal sewage and industrial wastewater treatment over a century. It has been demonstrated that some exopolysaccharide biosynthesis genes and the sigma factor (sigma54 or rpoN) were required for floc forming in some bacteria.

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Cottonseed meal (CSM) is a good source of dietary proteins but is unsuitable for human consumption due to its gossypol content. To unlock its potential, we developed a protein extraction process with a gossypol removal treatment to generate CSM protein isolate (CSMPI) with ultra-low gossypol content. This process successfully reduced the free and total gossypol content to 4.

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Article Synopsis
  • SETDB1 is a crucial regulator of specific genes and retroviral elements by adding a repressive mark (H3K9me3), but its other roles have been less explored.
  • A study in mouse embryonic stem cells found regions lacking typical repressive histone marks, enriched with the CTCF motif and linked to the Cohesin complex, leading to the discovery of specific domains called DiSCs.
  • SETDB1 and Cohesin work together to control gene expression and genome structure at these DiSCs; removing SETDB1 disrupts Cohesin binding and affects gene regulation, highlighting its role in stem cell maintenance and differentiation.
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Unlabelled: Mutations in the DNA mismatch repair gene MSH2 are causative of microsatellite instability (MSI) in multiple cancers. Here, we discovered that besides its well-established role in DNA repair, MSH2 exerts a novel epigenomic function in gastric cancer. Unbiased CRISPR-based mass spectrometry combined with genome-wide CRISPR functional screening revealed that in early-stage gastric cancer MSH2 genomic binding is not randomly distributed but rather is associated specifically with tumor-associated super-enhancers controlling the expression of cell adhesion genes.

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CDy1 is a powerful tool to distingusih embryonic stem cells for reprogramming studies and regeneration medicine. However, the stem cell selectivity mechanism of CDy1 has not been fully understood. Here, we report ALDH2 and ABCB1 as the molecular targets of CDy1, elucidated by live-cell affinity-matrix and ABC transporter CRISPRa library screening.

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A robust monoclonal antibody (mAb) bioprocess requires physiological parameters such as temperature, pH, or dissolved oxygen to be well-controlled as even small variations in them could potentially impact the final product quality. For instance, pH substantially affects N-glycosylation, protein aggregation, and charge variant profiles, as well as mAb productivity. However, relatively less is known about how pH jointly influences product quality and titer.

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Background: The compromised gut microbiome that results from C-section birth has been hypothesized as a risk factor for the development of non-communicable diseases (NCD). In a double-blind randomized controlled study, 153 infants born by elective C-section received an infant formula supplemented with either synbiotic, prebiotics, or unsupplemented from birth until 4 months old. Vaginally born infants were included as a reference group.

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Insulin and muscle contractions mediate glucose transporter 4 (GLUT4) translocation and insertion into the plasma membrane (PM) for glucose uptake in skeletal muscles. Muscle contraction results in AMPK activation, which promotes GLUT4 translocation and PM insertion. However, little is known regarding AMPK effectors that directly regulate GLUT4 translocation.

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What covalent modifications control the temporal ubiquitination of ERα and hence the duration of its transcriptional activity remain poorly understood. We show that GREB1, an ERα-inducible enzyme, catalyzes O-GlcNAcylation of ERα at residues T553/S554, which stabilizes ERα protein by inhibiting association with the ubiquitin ligase ZNF598. Loss of GREB1-mediated glycosylation of ERα results in reduced cellular ERα levels and insensitivity to estrogen.

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Sequential window acquisition of all theoretical fragment-ion spectra (SWATH) is a data-independent acquisition (DIA) strategy that requires a specific spectral library to generate unbiased and consistent quantitative data matrices of all peptides. SWATH-MS is a promising approach for in-depth proteomic profiling of Chinese hamster Ovary (CHO) cell lines, improving mechanistic understanding of process optimization, and real-time monitoring of process parameters in biologics R&D and manufacturing. However, no spectral library for CHO cells is publicly available.

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Article Synopsis
  • Mouse embryonic stem cells (ESCs) can occasionally enter a 2-cell (2C) stage-like state, which is marked by specific gene expressions that indicate early embryonic characteristics.
  • The study identifies NELFA, a maternal factor that influences the upregulation of 2C genes and enhances the developmental potential of ESCs, particularly when it interacts with Top2a.
  • Chemical suppression of glycolysis was found to encourage the transition to a 2C-like state, indicating that metabolic changes can impact cell fate without needing genetic manipulation.
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Dying tumor cells release intracellular potassium (K), raising extracellular K ([K]) in the tumor microenvironment (TME) to 40-50 mM (high-[K]). Here, we investigated the effect of high-[K] on T cell functions. Functional impacts of high-[K] on human T cells were determined by cellular, molecular, and imaging assays.

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Chinese hamster ovary (CHO) cells are the most prevalent mammalian cell factories for producing recombinant therapeutic proteins due to their ability to synthesize human-like post-translational modifications and ease of maintenance in suspension cultures. Currently, a wide variety of CHO host cell lines has been developed; substantial differences exist in their phenotypes even when transfected with the same target vector. However, relatively less is known about the influence of their inherited genetic heterogeneity on phenotypic traits and production potential from the bioprocessing point of view.

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Malted barley is the main source for fermentable sugars used by yeasts in the traditional brewing of beers but its use has been increasingly substituted by unmalted barley and other raw grain adjuncts in recent years. The incorporation of raw grains is mainly economically driven, with the added advantage of improved sustainability, by reducing reliance on the malting process and its associated cost. The use of raw grains however, especially in high proportion, requires modifications to the brewing process to accommodate the lack of malt enzymes and the differences in structural and chemical composition between malted and raw grains.

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Monoclonal antibodies (mAbs) are used as targeted therapies against cancers. These mAbs kill cancer cells via various mechanisms of actions. In this study, human embryonic stem cells (hESCs) was used as the immunogen to generate a panel of antibodies.

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