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noun
mass nounA resinous substance secreted as a protective covering by the lac insect, used to make varnish, shellac, sealing wax, dyes, etc.
lacquer, shellac, japan, enamel, glaze, polish, oil, resin, waxView synonyms
Origin
Late Middle English: from medieval Latin lac, lac(c)a, from Portuguese laca, based on Hindi lākh or Persian lāk.
Pronunciation
adjective
BiologyDenoting the ability of normal strains of the bacterium E. coli to metabolize lactose, or the genetic factors involved in this ability (which is lost in some mutant strains)
‘the lac operon’- ‘In addition to the lac operon, a number of other synthetic and natural genetic circuits have been analyzed for robustness and evolvability.’
- ‘This system is probably still the best-understood regulatory system in eukaryotic biology and today is taught in every textbook of genetics and cell biology, alongside the lysis-lysogeny decision of and the lac operon of E. coli.’
- ‘Other events are correlated with the stable exploration of new niches, like the acquisition of the lac operon by E. coli or pathogenicity islands by Salmonella.’
- ‘These strains might not even use their lac gene products to metabolize lactose.’
- ‘A metabolite of lactose binds to the lac repressor, changing the protein's shape and thereby causing it to loosen its grip on the DNA.’
Origin
1940s: abbreviation of lactose.
Pronunciation
noun
- variant spelling of lakh
Pronunciation
abbreviation
(in the RAF) Leading Aircraftman or Leading Aircraftwoman.
