[1] During his postdoctoral at the University of Liverpool (1955-1960), Nick produced some of the most historically significant findings from his research; which began with his development of the first axenic cultures of both the Bristol and Bergerac strains of Caenorhabditis elegans in 1956.

[3][6][7] In 1957 & 1958, Nick was a Travelling Fellow of the British Medical Research Council (MRC), funded by a Rockefeller grant (on leave from the University of Liverpool).

During the tenure of his fellowship, he worked with Ellsworth C. Dougherty and Eder L. Hansen in the Lab of Comparative Biology at the Kaiser Foundation Research Institute in Richmond CA.

[8] Among other areas of research, an objective was to determine the nature of undefined factors of Rb and Cb required for axenic culture of Caenorhabditis briggsae.

In their last publications on the subject,[10][11] the authors described for the first time a fully defined medium (GS-25), which could sustain the development of C. elegans from larvae into adult, with just once the production of an F1 generation.

Brenner's initial thoughts on the use of C. briggsae are recorded notably in his letter to Max Perutz[13] and proposal to the MRC,[13] both in 1963: Part of the success of molecular genetics was due to the use of extremely simple organisms which could be handled in large numbers...We should like to attack the problem of cellular development in a similar fashion, choosing the simplest possible differentiated organism and subjecting it to the analytical methods of microbial genetics...We think we have a good candidate in the form of a small nematode worm, Caenorhabditis briggsiae...To start with we propose to identify every cell in the worm and trace lineages.

[16] When it came time for this work to begin, Nicholas took L. N. Staniland's extraction of the Bristol strain of C. elegans (found in mushroom compost in England), produced the axenic culture of it, and brought it to Dougherty's lab.

[8][15] Nobel prizes have been awarded in 2002 and 2006 for studies using N2 line, Bristol strain C. elegans as a model systemref name=":7" /> Nicholas was an author of The Biology of Free-Living Nematodes (1975), published by Clarendon Press, Oxford.

[citation needed] Provided knowledge and skills, with collegial conduit Ellsworth C. Dougherty, on species C. elegans vitally important to Sydney Brenner's work.

[citation needed] Brenner shared in a Nobel Prize in 2002 "for their discoveries concerning genetic regulation of organ development and programmed cell death".