Thus, at least some HCC tumors may be auxotrophic
for arginine and require arginine supply from extracellular sources (110).
In these models, the auxotrophic
strains of Salmonella Typhimurium, A1 strain (deficient in leucine and arginine synthesis) and the A1-R strain (deficient in leucine and arginine synthesis, with greater capacity to eliminate tumor cells), maintained their antitumor activity and did not cause toxic effects in the host due to its greater affinity for tumor tissue .
Interestingly, the reversal of argininosuccinate lyase activity makes these cells auxotrophic
for arginine, which can have therapeutic applications for FH-deficient cancers (35).
Therefore, the auxotrophic
mutants which are unable to multiply in the environment were designed.
Of the 12 isolates, 7 were double auxotrophic
mutants with G6P and G3P (mean MIC 384 mg/L), 3 were auxotrophic
only for G3P (mean MIC 597 mg/L), and 2 were capable of using both substrates and exhibited high-level resistance (MIC >1,024 mg/L).
selectable markers involved in amino acid or nucleotide biosynthesis have also been used.
More congruent nichespecific phenotypes were observed in isoleucine/valine auxotrophic
anomalus as a platform to produce recombinant proteins such as the design of specific expression vectors and the generation of auxotrophic
Stationary growth cultures of histidine auxotrophic
Salmonella typhimurium (2 x [10.sup.9] cells/mL) TA97, TA98, TA100, TA102, and TA1535 strains were obtained at 37[degrees]C in lysogenic broth (LB, 10 g/L tryptone; 5 g/L yeast extract; 10 g/LNaCl) containing 8 [micro]g/mL ampicillin and 2 [micro]g/mL tetracycline (only for TA102).
(1977) The isolation and preliminary characterisation of auxotrophic
and analogue resistant mutants of the moss, Physcomitrella patens.
The colonies which showed growth on complete medium (containing all the essential amino acids) but not on minimal medium were considered as auxotrophic
(mutants).The mutants were then screened for hyper- production of alginate against the parent strain by using the pre-optimized conditions for wild culture.
Mutants of Psm using pTn5cat1 were obtained through conjugal transfer of pMC505 containing the transposable element from the auxotrophic