Plasmid vectors for expression in Caenorhabditis elegans harbouring a heat inducible promoter nucleotide sequence, a synthetic intron nucleotide sequence optionally containing a Shine-Dalgarno sequence for efficient shuttling between C. elegans and E. coli, optionally a nucleotide sequence coding for a nuclear localisation signal or secretion signal, a nucleotide sequence coding for a recognizable tag, optionally a nucleotide sequence coding for a fluorescent protein, a nucleotide sequence coding for a protease cleavage site, a multiple cloning site containing a nucleotide sequence coding for an eukaryotic, such as human, protein or a nucleic acid molecule and a nucleotide sequence coding for termination of translation, are described. Methods of particularly large scale production of eukaryotic, such as human, proteins and nucleic acid molecules in nematodes are also described.