Summary

Molecular biology and gene expression regulation examine the molecular organization, function, and interactions of DNA, RNA, and proteins. This collection covers the mechanisms through which genetic information is replicated, transcribed, processed, translated, and regulated, including transcriptional control, RNA metabolism, post-transcriptional regulation, protein synthesis, and molecular signaling.

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Topic Review
Ferroptosis: Core Mechanisms and Metabolic Regulation
This entry summarizes the molecular basis of ferroptosis, its metabolic and signalling regulation, its roles in major disease groups, and the principal therapeutic strategies targeting this cell-death pathway. Ferroptosis is an iron-dependent form of regulated cell death driven by uncontrolled peroxidation of polyunsaturated fatty acid-containing phospholipids. It is morphologically and biochemically distinct from apoptosis, necroptosis, autophagy, and pyroptosis and is characterized by iron accumulation, glutathione depletion, glutathione peroxidase 4 (GPX4) inactivation, and lipid peroxide accumulation. The core execution machinery involves labile iron, PUFA-phospholipid remodelling by ACSL4 and LPCAT3, lipoxygenase- and oxidoreductase-mediated lipid peroxidation, and Fenton chemistry. Cellular defence is organized around the system Xc-/GSH/GPX4 axis and GPX4-independent systems, including FSP1-CoQ10-NADPH, GCH1-BH4-DHFR, DHODH-CoQH2, and MBOAT1/2-mediated phospholipid remodelling. Ferroptosis is regulated by p53, NRF2, MAPK-AMPK signalling, hypoxia, mitochondrial metabolism, and immune cells such as macrophages. It contributes to cancer biology, cardiovascular and metabolic diseases, liver injury, neurological disorders, and inflammatory conditions. Therapeutic strategies include ferroptosis inducers, iron chelators, radical-trapping antioxidants, natural products, and nanomedicine, but biomarker validation and clinical translation remain unresolved.
  • 10
  • 02 Nov 2026
Topic Review
Glycosylation in Immune Regulation and Inflammatory Diseases
This entry explores the multifaceted roles of protein and RNA glycosylation in modulating innate and adaptive immunity, highlighting its impact on inflammasome activation and inflammatory disease pathogenesis, and discussing emerging glycan-targeted therapies and diagnostic tools.
  • 15
  • 28 Oct 2026
Topic Review
Enzyme Electrophoresis
Enzyme electrophoresis is the separation of enzymes by their movement in an electric field through a supporting medium. Gel-based separation produces spatially resolved protein bands that can be examined for catalytic activity. In gel zymography, substrate conversion generates a localized signal corresponding to an active enzyme form [1]. Native electrophoresis separates proteins under conditions that can preserve folded structures or associated molecular components [2]. Combining native separation with an in-gel activity reaction links a resolved complex to its catalytic function [3]. Electrophoretic patterns may also represent variation among enzyme forms across multiple loci [4]. The observed pattern reflects protein migration, the separation matrix, the biochemical conditions maintained during electrophoresis, and the specificity of the subsequent activity-detection reaction [5].
  • 7
  • 25 Oct 2026
Topic Review
Enzyme Recovery
Enzyme recovery is the downstream segment of bioprocessing in which an enzyme is separated from the fermentation broth and brought to a defined purity and stability [1]. It begins once the fermentation has achieved peak yield, when the enzyme-containing culture is harvested and processed through a succession of discrete unit operations [2]. Extracellular enzymes are recovered from the cell-free supernatant after biomass removal by centrifugation or filtration, whereas intracellular enzymes require cell disruption to release the product before debris removal [2][3]. Subsequent operations concentrate and fractionate the crude extract, typically by ultrafiltration and chromatographic separation [4]. A defining quantitative feature is that overall recovery yield is the product of the yields of the individual steps, so that even a credible per-step yield of 90% across a multistage process substantially reduces final output, an effect compounded by activity loss at each manipulation owing to the labile nature of most enzymes [2]. The term encompasses this entire succession of operations together with the yield and purity metrics that characterize its performance [1].
  • 4
  • 25 Oct 2026
Topic Review
Plasmid Isolation
Plasmid isolation denotes the experimental procedure by which covalently closed circular plasmid DNA is separated from the chromosomal DNA, RNA, proteins, and other cellular constituents of a bacterial host, yielding a plasmid preparation sufficiently free of contaminants for downstream molecular manipulation [1]. The procedure exploits the topological and size difference between the supercoiled plasmid molecule and the much larger, linear chromosomal DNA: under alkaline conditions in the presence of a detergent, both species are released from the cell and their hydrogen bonds are disrupted, but the two strands of the covalently closed plasmid remain topologically intertwined and in close proximity, whereas the chromosomal strands, being enormously long and bound to cellular structures, cannot readily find their complementary partners [1][2]. Upon neutralization with an acidic salt, the chromosomal DNA and associated denatured proteins and lipids coagulate into an insoluble aggregate that is removed by centrifugation or filtration, while the plasmid DNA, having reannealed into its double-stranded closed circular form, remains in the soluble fraction [2]. The term encompasses the entire preparative workflow—cell harvesting and resuspension, alkaline lysis, neutralization and clarification, and final purification of the plasmid DNA—and spans preparative scales ranging from analytical “miniprep” quantities for clone screening to large-scale manufacturing of transfection-grade or clinical-grade plasmid DNA [3][4]. Contemporary implementations integrate the lysis chemistry with solid-phase capture on silica membranes under chaotropic conditions or with anion-exchange chromatography, which retain plasmid DNA while permitting residual RNA, protein, and endotoxin to be washed away before elution of the purified species [4][5].
  • 6
  • 25 Oct 2026
Topic Review
Clinical Lipidomics: Biomarkers, Pathophysiology, and Technological Advances
Lipidomics has emerged as a pivotal omics discipline for understanding the complex lipid networks underlying human health and disease. By utilizing advanced mass spectrometry and bioinformatics, clinical lipidomics transcends traditional lipid measurements, offering deep insights into disease mechanisms, biomarker discovery, and targeted therapies across a spectrum of conditions including cardiometabolic, inflammatory, psychiatric, oncological, and gynecological disorders. This review synthesizes recent methodological advancements and clinical applications, highlighting the transition from research to precision medicine.
  • 29
  • 26 Oct 2026
Topic Review
Plasmid Transfer Dynamics
Plasmid transfer dynamics is the pattern of plasmid movement and establishment among cells over time. During conjugative transfer, DNA-processing enzymes cleave and rejoin plasmid DNA as part of the transfer reaction; relaxases form a transient covalent linkage to the DNA strand being processed [1]. At the population level, transfer interacts with host growth, plasmid maintenance, and the ecological distribution of compatible recipients [2]. Plasmids can encode their own transfer machinery or use functions supplied by other mobile genetic elements, producing different routes of movement through a community [3]. Donor-recipient recognition provides an additional molecular constraint: variants of the F-like plasmid protein TraN recognize particular recipient outer-membrane proteins [4]. Contact patterns, recognition, DNA transfer, and subsequent persistence jointly shape the observed distribution of plasmid-bearing cells [5].
  • 5
  • 25 Oct 2026
Topic Review
Gene Expression Regulation
Gene expression regulation is the control of the production, processing, localization, and persistence of functional gene products. Regulatory events act at multiple stages between a DNA sequence and its RNA or protein products. Chemical modifications of RNA can alter transcript processing, recognition, translation, and turnover through interactions with proteins that install, remove, or bind the modifications. Protein abundance reflects both RNA availability and the rates of protein synthesis and degradation [1][2]. Alternative splicing regulates which RNA segments are retained in mature transcripts through sequence signals and associated regulatory proteins [3]. Intracellular RNA transport further positions transcripts at particular cellular sites, where local translation establishes spatial patterns of protein production. These interconnected processes give gene expression temporal, quantitative, and spatial organization [4][5].
  • 4
  • 25 Oct 2026
Topic Review
Gene Expression Profiling
Gene expression profiling designates the systematic determination of the pattern of genes expressed at the level of genetic transcription in a specific cell, tissue, or biological condition. Its defining operational feature is the parallel measurement of transcript abundance for thousands of genes simultaneously, generating a global quantitative description—a profile—of the transcriptional state of the biological sample rather than a measurement of any single transcript in isolation. The term encompasses the measurement of expressed RNA transcripts across defined biological states, including the comparison of differentially expressed transcripts among tissues, cells, strains, or experimental conditions [1]. Two principal technological platforms realize this parallel measurement: hybridization-based microarrays, in which labeled target sequences are annealed to ordered arrays of complementary oligonucleotide probes and the resulting signal intensities report relative transcript abundance [2][3], and sequencing-based RNA-Seq, in which the population of transcripts is converted to cDNA, sequenced in a massively parallel manner, and the resulting reads are mapped and counted to yield transcript-level quantification [4]. The conceptual scope of gene expression profiling is defined by its unit of analysis—the transcriptome, the complete set of RNA transcripts present in a cell or sample at a given moment—and by its output—a comparative, genome-scale expression pattern that links molecular information to cellular phenotype and function [1][4]. The profiling enterprise thus establishes a functional annotation of the genome in operation, capturing the subset of genes that is active, the relative levels of their expression, and the changes in these patterns that accompany physiological, developmental, or pathological states [5].
  • 2
  • 25 Oct 2026
Topic Review
Eukaryotic Gene Editing
Eukaryotic gene editing is the targeted alteration of DNA sequences in the nuclear or organellar genomes of eukaryotic cells. Programmable recognition components position an editing activity at a selected genomic site; in CRISPR systems, a guide RNA specifies complementary DNA recognized by a Cas protein [1][2]. Nuclease editors introduce DNA breaks that cellular repair processes resolve into sequence changes. Other editing systems combine target recognition with enzymes that modify bases or copy new sequence information into DNA [3]. DNA base editors couple a targeting protein to a nucleobase-modifying enzyme, enabling particular base-pair substitutions without requiring a double-strand break. The molecular components, accessible target sequence, and participating repair reactions specify the range of possible edits, including substitutions, insertions, and deletions [4].
  • 5
  • 25 Oct 2026
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