Resistance to acetohydroxamate acquired by slow adaptive increases in urease in cultured tobacco cells

Journal Article · Mon Jun 01 04:00:00 EDT 1981 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.67.6.1133· OSTI ID:6461405

Yamaya, T; Filner, P

Urease activity of tobacco XD cells (1U cells) had undergone a 4-fold increase (4U cells) during a year of growth on urea. A clone of 4U cells gave rise to 12U cells during another year of growth on urea. The doubling time of 12U cells on urea is 2.2 days, compared to about 4 days for 1U cells, while 1U and 12U cells double in 2 days on nitrate. Acetohydroxamic acid (AHA), a specific inhibitor/reversible inactivator of jack bean urease, affects tobacco cells urease similarly. Fifty per cent inhibition of growth by AHA occurred at 20 micromolar in 1U cells growing on urea and at 165 micromolar in 12U cells growing on urea, but at 600 micromolar for either 1U or 12U cells growing on nitrate. When 12U cells were grown on urea with 100 micromolar AHA, extractable urease activity decreased 80% within 2.5 hours and remained at this level for 2 weeks; the doubling time increased to 3.7 days, and intracellular urea rose 2-fold, compared to 12U cells grown on urea without AHA. Urease of 12U cells inactivated by AHA in vivo could be reactivated to its pre-AHA level by incubation at 30 C after extraction and separation from free AHA. AHA inhibited incorporation of /sup 15/N from (/sup 15/N) urea into Kjeldahl nitrogen in the cells, in spite of the increased intracellular urea. These results indicate that AHA acts primarily by inhibiting urease action, rather than by inhibition of formation of urease protein or of uptake of urea. Because 12U cells are 8 times more tolerant of AHA than 1U cells, it is likely that growth on urea in the presence of AHA should select strongly for cells with high urease.

• Research Organization: Michigan State Univ., East Lansing
• DOE Contract Number: AC02-76ER01338
• OSTI ID: 6461405
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 67:6; ISSN PLPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
AMIDES
AMIDINASES
BIOCHEMISTRY
BIOLOGICAL EFFECTS
CARBONIC ACID DERIVATIVES
CARBONIC ACID ESTERS
CELL CULTURES
CHEMICAL REACTIONS
CHEMISTRY
CLONING
COMPARATIVE EVALUATIONS
DECOMPOSITION
DNA
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESTERS
GENES
GRAPHS
GROWTH
HYDROLASES
HYDROLYSIS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LYSIS
METABOLISM
NICOTIANA
NITROGEN 15
NITROGEN ISOTOPES
NON-PEPTIDE C-N HYDROLASES
NUCLEI
NUCLEIC ACIDS
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANT CELLS
PLANTS
SOLVOLYSIS
STABLE ISOTOPES
TRACER TECHNIQUES
UREA
UREASE