Extraction of a Hyperplasia-Inducing factor

Abstract

Ahyperplasia-inducing or etiological factor was extracted from the bacterium transmitting bacterial gill disease. The extract induces the fusion of gill lamellae and/or filaments, hypertrophy of gill lamellae, islands of hyperplasia scattered irregularly along the filament and an occasional clubbing of the filaments. The hyperplasia was comprised of lesions with the characteristics of bacterial gill disease. There were no essential differences in surface ultrastructure or cell organization between lesions occurring as the result of extract-induction and those due to artificial or natural infection caused by the bacteria.