TY - JOUR
T1 - Nutritional requirements of wild-type and folate transport-deficient Leishmania donovani for pterins and folates
AU - Beck, Joanne T.
AU - Ullman, Buddy
PY - 1990/12
Y1 - 1990/12
N2 - The nutritional requirements for folates and pterins were assessed for two strains of Leishmania donovani promastigotes, a wild-type (D1700) parental strain and a mutant derivative (MTXA5) which possesses a markedly diminished capacity to transport both [3H]folate and [3H]methotrexate (MTX) [14]. Both L. donovani strains have an absolute growth requirement for an exogenous pterin, since their proliferation could not be sustained in completely defined medium lacking either a pterin or a folate. Supplementation of the growth medium by many of a spectrum of folates and pterins could support growth of the wild-type cell line. Surprisingly, however, the MTXA5 strain could not thrive in folate-deficient medium fortified with any of the pterins that promoted wild-type cell division, including biopterin and neopterin. The relationship between the incapacity of MTXA5 cells to transport folate and methotrexate and their inability to multiply in folate-deficient medium supplemented with pterins was evaluated using genetic approaches. First, an independently generated MTX-resistant mutant, MTXB4, was isolated in 1 mM MTX. The phenotype of the MTXB4 cells was like that of MTXA5 cells since they were unable to transport [3H]MTX and [3H]folate or grow in folate-deficient medium supplemented with pterins. Second, three revertants of the MTXA5 cells were selected for their ability to grow in 1 μM biopterin. All three revertants had regained [3H]folate and [3H]MTX transport capability concomitant with growth sensitivity to methotrexate toxicity. These observations provide genetic evidence that the competence of L. donovani to transport [3H]folate and [3H]MTX and the capability of the organisms to utilize pterins as a nutritional factor are influenced by a common genetic locus.
AB - The nutritional requirements for folates and pterins were assessed for two strains of Leishmania donovani promastigotes, a wild-type (D1700) parental strain and a mutant derivative (MTXA5) which possesses a markedly diminished capacity to transport both [3H]folate and [3H]methotrexate (MTX) [14]. Both L. donovani strains have an absolute growth requirement for an exogenous pterin, since their proliferation could not be sustained in completely defined medium lacking either a pterin or a folate. Supplementation of the growth medium by many of a spectrum of folates and pterins could support growth of the wild-type cell line. Surprisingly, however, the MTXA5 strain could not thrive in folate-deficient medium fortified with any of the pterins that promoted wild-type cell division, including biopterin and neopterin. The relationship between the incapacity of MTXA5 cells to transport folate and methotrexate and their inability to multiply in folate-deficient medium supplemented with pterins was evaluated using genetic approaches. First, an independently generated MTX-resistant mutant, MTXB4, was isolated in 1 mM MTX. The phenotype of the MTXB4 cells was like that of MTXA5 cells since they were unable to transport [3H]MTX and [3H]folate or grow in folate-deficient medium supplemented with pterins. Second, three revertants of the MTXA5 cells were selected for their ability to grow in 1 μM biopterin. All three revertants had regained [3H]folate and [3H]MTX transport capability concomitant with growth sensitivity to methotrexate toxicity. These observations provide genetic evidence that the competence of L. donovani to transport [3H]folate and [3H]MTX and the capability of the organisms to utilize pterins as a nutritional factor are influenced by a common genetic locus.
KW - Folate
KW - Genetics
KW - Leishmania
KW - Mutant
KW - Pterin
KW - Transport
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U2 - 10.1016/0166-6851(90)90147-E
DO - 10.1016/0166-6851(90)90147-E
M3 - Article
C2 - 2090944
AN - SCOPUS:0025187502
VL - 43
SP - 221
EP - 230
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
SN - 0166-6851
IS - 2
ER -