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Topic Review Peer Reviewed
Hybrid Artificial Intelligence–Monte Carlo Methods for Radiotherapy Dose Calculation
Hybrid artificial intelligence (AI) and Monte Carlo (MC) methods for radiotherapy dose calculation refer to computational approaches that integrate machine learning models with physics-based MC simulation to achieve both fast and accurate estimation of radiation dose distributions. These methods use AI to approximate complex MC dose calculations with greatly reduced computation time, while retaining MC simulation as the standard for physical fidelity and validation. The hybrid strategy supports real-time or near-real-time dose evaluation, enables adaptive treatment workflows, and allows accurate modeling of photon and electron beams in heterogeneous patient anatomy. By combining the strengths of data-driven prediction and physics-based simulation, hybrid AI and MC methods provide a pathway toward efficient and high-precision dose calculation in modern radiotherapy.
  • 63
  • 03 Mar 2026
Topic Review
Alkaloid Biosynthesis
Alkaloid biosynthesis is the genetically encoded, enzyme-mediated formation of alkaloids: nitrogen-containing natural products produced through specialized metabolic pathways. It encompasses the conversion of central-metabolic precursors into alkaloid core structures and the subsequent reactions that generate structurally distinct alkaloid products. Alkaloid-producing bacteria, fungi, and plants possess different pathway architectures and enzyme repertoires; consequently, alkaloid classes do not necessarily share a single precursor, sequence of intermediates, or biosynthetic mechanism [1]. In established plant pathways, amino acids and their derivatives commonly provide carbon and nitrogen inputs for the formation of alkaloid frameworks [2]. Biosynthesis includes scaffold-forming transformations and downstream tailoring reactions, such as oxidation, reduction, methylation, acylation, and glycosylation, which alter the molecular structure of pathway intermediates [1][3]. The term denotes endogenous biological production and its associated enzymes and genes; it excludes laboratory chemical synthesis, semisynthesis, extraction, isolation, and structural analysis of alkaloids.
  • 7
  • 23 Sep 2026
Topic Review
Drug Transport Proteins
A drug binding protein is a protein that directly and reversibly associates with a therapeutic agent through a molecular binding site and thereby contributes to the agent’s cellular recognition, intracellular concentration, transmembrane movement, sequestration, metabolism, or pharmacological response. Within oncology and drug transport–resistance mechanisms, the term principally encompasses membrane proteins that bind anticancer drugs as transport substrates or inhibitors, including ATP-binding cassette (ABC) efflux transporters and solute carrier (SLC) uptake transporters [1][2][3]. Drug binding occurs through noncovalent interactions involving hydrophobic contacts, hydrogen bonds, electrostatic forces, aromatic interactions, and conformational complementarity between the drug and the protein’s binding cavity or translocation pathway. Binding affinity, substrate specificity, binding-site accessibility, transporter conformation, expression level, and coupling to ATP hydrolysis or solute gradients govern the extent of drug movement across cellular membranes [2][3][4]. In tumour cells, these protein–drug interactions regulate intracellular drug exposure and can contribute to reduced drug accumulation and multidrug-resistance phenotypes [1][3][4].
  • 2
  • 24 Sep 2026
Topic Review
Biosynthetic Gene Cluster (BGC)
A biosynthetic gene cluster (BGC) is a contiguous, functionally coordinated genomic locus that encodes the enzymatic and regulatory machinery required for the biosynthesis of a specialized natural product or a defined family of structurally related metabolites. In microbial genomes, a BGC commonly includes one or more core biosynthetic genes encoding scaffold-forming enzymes, together with genes for tailoring enzymes that modify the molecular scaffold, transport proteins, pathway-specific regulators, precursor-supply functions, and, where relevant, self-resistance or immunity mechanisms [1][2]. The coordinated expression and activity of these genes direct the conversion of primary metabolites into a characteristic natural-product scaffold and its subsequent chemical diversification. BGCs are recognized as genomic units through the physical co-localization of genes whose protein products collectively constitute a biosynthetic pathway; their boundaries encompass the genes contributing directly to metabolite assembly, modification, regulation, export, or producer protection [1][3].
  • 1
  • 24 Sep 2026
Topic Review
Biosynthetic Pathways
Biosynthetic pathways are organized sequences of enzyme-catalyzed biochemical reactions through which microorganisms convert primary metabolic precursors into natural products and their structural derivatives. Within microbial natural-product biosynthesis, a pathway comprises the participating substrates, intermediates, cofactors, enzymes, regulatory elements, and transport or resistance functions that collectively determine the assembly and chemical maturation of a metabolite [1][2]. Core biosynthetic enzymes generate characteristic molecular scaffolds through reactions such as condensation, carbon–carbon bond formation, cyclization, and chain extension, while tailoring enzymes introduce structural features through oxidation, reduction, methylation, glycosylation, halogenation, acylation, or related transformations [1][3]. The pathway therefore encompasses the full biochemical route from precursor recruitment and scaffold formation to enzymatic modification, product release, and, where encoded, intracellular handling of the resulting natural product [2][3].
  • 1
  • 24 Sep 2026
Topic Review
Antifungal Proteins
Antifungal proteins are proteinaceous molecules that inhibit fungal growth, viability, morphogenesis, spore germination, or other cellular processes required for fungal propagation. Within fungal biology and pharmacology, the term encompasses proteins and peptides produced by fungi, plants, animals, and microorganisms that exert activity against fungal cells through defined molecular interactions [1][2]. Their structural classes include cysteine-rich disulfide-stabilized proteins, defensins, lectins, ribosome-inactivating proteins, protease inhibitors, and enzymes or protein domains with fungistatic or fungicidal activity [1][3]. Antifungal activity may involve binding to fungal cell-wall components or membrane lipids, perturbation of membrane integrity, cellular internalization, induction of reactive oxygen species, disruption of ion homeostasis, interference with cell-wall biosynthesis, or activation of regulated cell-death pathways. The defining scope of antifungal proteins comprises their molecular capacity to recognize or perturb fungal cellular structures and physiological processes, resulting in measurable suppression of fungal growth or survival [2][4].
  • 1
  • 24 Sep 2026
Topic Review
Cholesterol Transport Proteins
Cholesterol transport proteins are proteins that bind, recognize, translocate, exchange, import, export, or distribute cholesterol among extracellular lipoprotein particles, cellular membranes, and intracellular organelles. They coordinate cholesterol flux through receptor-mediated uptake of lipoprotein-derived cholesterol, transmembrane transport across cellular or organellar membranes, efflux to extracellular acceptors, and non-vesicular transfer at membrane contact sites [1][2][3]. This functional group includes lipoprotein receptors and apolipoprotein-associated components, ATP-binding cassette transporters, Niemann–Pick C proteins, and soluble lipid-transfer proteins containing sterol-binding domains [4]. Their activities depend on cholesterol-binding sites, membrane association, protein–protein interactions, concentration gradients, and, for active transporters, energy coupling. Together, cholesterol transport proteins maintain the heterogeneous distribution of unesterified cholesterol required across the plasma membrane, endosomes, lysosomes, endoplasmic reticulum, mitochondria, and other cellular compartments [2][3][4].
  • 1
  • 24 Sep 2026
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