Nikolai Cholodny

Nikolai Grigoryevich Cholodny (Никола́й Григо́рьевич Холо́дный; 22 June 1882 – 4 May 1953) was an influential microbiologist who worked at the University of Kiev, Ukraine in the USSR during the 1930s.

He is known for the Cholodny–Went model, which he developed independently with Frits Warmolt Went of the California Institute of Technology. Despite being associated with the same theory, the two men never actually met.

Cholodny worked in the A.V. Fomin Botanical Garden, attached to the University of Kiev. He was one of the pioneers of the concept that microbes adhere to surfaces, using the technique of first placing glass slides in earth for a measured time period, then using a microscope to examine the slides. The Prokaryote Leptothrix cholodnii is named after him. In 1927 Cholodny proposed that the cells of the coleoptile are first polarized under the influence of uneven exposure to light, so growth hormone can diffuse more rapidly towards the side in the shade than in any other direction. Went reached the same conclusion in 1928, and the two scientists' names have been attached to the controversial Cholodny-Went theory.