pleomorfne

Pleomorfne is an adjective used in biology to describe organisms, cells, or viral particles that lack a single, uniform shape and can take multiple forms. The root is from Greek pleion “more” and morphe “form,” and in some languages such as Czech, Slovene, or Croatian the term appears as pleomorfne (or pleomorfné) to denote pleomorphism.

In microbiology, pleomorphic bacteria show variable shapes in response to growth conditions. A classic example is the genus Mycoplasma, which lacks a rigid cell wall and can assume coccoid, filamentous, or pleomorphic forms. Environmental factors, phase variation, and nutrient availability contribute to shape variation. Other bacteria may become filamentous or irregular when stressed or during certain life stages.

In pathology, pleomorphism refers to variation in size and shape of cells and their nuclei within a tumor. Nuclear pleomorphism includes irregular nuclear membranes, increased nuclear-to-cytoplasmic ratio, and hyperchromasia. The degree of pleomorphism is used as part of histological grading, helping to assess malignancy and prognosis.

In virology, pleomorphism describes viruses that do not have a single rigid morphology. Some enveloped viruses exhibit filamentous, spherical, or pleomorphic forms; the description reflects variability in virion shape observed under electron microscopy.

See also: pleomorphism.