An absorptive epithelial cell of the intestinal lining. Enterocyte-lineage progenitors and terminally differentiated villus enterocytes need not have the same regenerative potential.

A specialized mucus-secreting epithelial cell, present in the intestinal lining and other mucosal tissues.

A specialized intestinal epithelial cell that senses local conditions and releases signalling products, including hormones.

A specialized epithelial sensory cell biological population with characteristic apical morphology and context-dependent signalling roles.

A specialized secretory cell normally found at the base of mammalian small-intestinal crypts. Its local antimicrobial and niche-support roles do not imply that all intestinal stem-cell systems require a Paneth-cell arrangement.

A keratinocyte is the principal epithelial cell of the epidermis and produces keratin intermediate filaments. Dividing basal keratinocytes supply descendants that differentiate, move toward the surface and form the protective barrier. Terminal differentiation changes both protein expression and cellular architecture; the outermost mature cells lose their nuclei. This continual renewal separates a proliferative compartment from a mechanically protective surface. ^[ref]

Madin-Darby canine kidney cell, used in three-dimensional epithelial cyst and polarity assays.

The cultured epithelial model can form polarized layers or epithelial cysts, making it useful for testing vesicle trafficking and apical-basal organization. Cell-line origin, culture geometry and the particular clone matter when comparing results across experiments. ^[ref]

Epitaxial crystal growth confined to exposed substrate regions defined by a growth-inhibiting mask. Pattern position and pitch can control wire nucleation, while transport and facet-dependent incorporation influence growth rate and composition.

An interaction in which the sign of a genetic change’s fitness effect depends on the genetic background. It constrains which steps increase fitness along an adaptive walk.

Testing whether forced activity of a downstream candidate restores an output after another gene is impaired. Rescue supports functional sufficiency in the tested context, but parallel routes and overexpression can also bypass a defect.

A regulatory state associated with chromatin, DNA modification or a self-maintaining regulatory process. Persistence through cell divisions and transmission through sexual reproduction are distinct properties.

Transmission of an epigenetic effect beyond directly exposed generations, after excluding alternative explanations such as sequence change and parental provisioning.

An oocyte-derived signalling protein that activates the epidermal growth factor receptor in neighbouring Drosophila melanogaster follicle cells, helping establish ovarian polarity.

The characteristic early postimplantation mouse embryo arrangement, with cup-shaped epiblast, extraembryonic ectoderm and surrounding visceral endoderm. It differs geometrically from a flat embryonic disc.

The early lumen associated with epithelializing mouse epiblast. Its formation involves polarity and apical membrane separation rather than requiring elimination of a central mass by apoptosis.

A small molecule that inhibits transcription through interaction with XPB. Its known target supplies a biochemical comparator, not evidence that another compound has the same target.^[ref]

An equilibrium polymer-depletion profile describes how chain conformations and wall exclusion affect concentration without imposed flow. It is not, by itself, a prediction of the concentration field in a flowing polymer solution.

Flow deforms and orients polymers, and hydrodynamic interactions with a nearby wall can produce cross-stream migration. Brownian diffusion opposes the resulting concentration gradients. In a simplified one-dimensional description with constant diffusivity, $J_z=c{v}_{\mathrm{mig}}-D{\partial }_{z}c$ shows why a steady profile requires migration and diffusion information in addition to the equilibrium depletion length. A rigid-polymer calculation in simple shear predicts migration away from the wall and a flow-dependent depletion layer; this is a specified model, not a universal direction for every polymer and flow.^[ref]

Oxygen-centred attack of an enolate on an acylating reagent forms an enol ester or carbonate. Carbon acylation gives a different connectivity, so the ambident nucleophile's two resonance representations should not be confused with two equivalent products.

Enolate alkylation forms a carbon–carbon bond by attack of an enolate carbon on an alkyl electrophile, commonly through an SN2 reaction. Solvent, counterion, aggregation and electrophile identity affect competition with oxygen alkylation.