Amino-acid transport into cultured tobacco cells

Berry, Sandra L.; Harrington, Helen; Bernstein, R. L.; Henke, Randolph R.

doi:10.1007/bf00385534

Cited by 11 publications

(9 citation statements)

References 39 publications

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“…Some researchers who use tris buffers in their preincubation solutions have concluded that calcium is required in the preincubation solution in order to obtain uptake rate increases for amino acids (2,8,18). Others have reported that increases in uptake rate do not require the presence of calcium in the preincubation solution (11,15).…”

Section: Discussionmentioning

confidence: 99%

“…This effect has been observed using a number of species and for a broad range ofsubstrates: phosphate, potassium, chloride, glycine, glucose, and guanosine monophosphate (11); sulfate (10); L-serine (18); malate, glycerate-3-P, uracil, and several amino acids (8) (2,7,8,10,18). However, other researchers have demonstrated that an enhanced uptake rate can be induced without the addition of calcium to the preincubation solution (6,11,15).…”

Section: Introductionmentioning

confidence: 95%

“…Transport workers also differ in their use of pH buffers in preincubation and incubation solutions. Some routinely employ pH buffers (2,7,8,10,15,18) while others do not (11,13,14, 19 nally isolated from pith, were maintained in LS medium3 as previously described (3). Subculturing was performed every 7 d by adding 50 ml of fresh LS medium to a culture flask and then dividing this suspension between two 125-ml Erlenmeyer flasks.…”

Section: Introductionmentioning

confidence: 99%

“…Since Epstein's (5) early report that calcium is required for the integrity of selective ion transport mechanisms, most transport studies have employed media which contain calcium. It has been reported that the high rates of solute uptake which are observed after preincubation are dependent upon calcium in the medium (2,7,8,10,18). How-ever, other researchers have demonstrated that an enhanced uptake rate can be induced without the addition of calcium to the preincubation solution (6,11,15).…”

mentioning

confidence: 99%

“…Transport workers also differ in their use of pH buffers in preincubation and incubation solutions. Some routinely employ pH buffers (2,7,8,10,15,18) while others do not (11,13,14,19). Reinhold's laboratory initially employed pH buffers (17), but because buffers were shown to influence the amino acid uptake process, they discontinued the use of buffers (1,16).…”

mentioning

confidence: 99%

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Amino Acid Transport in Suspension-Cultured Plant Cells

Schneegurt

McDaniel²

1986

Plant Physiol.

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The rate at which L-leucine was transported into suspension-cultured Nicotiana tabacum cv Wisconsin 38 cells increased more than 2-fold over a period of hours when the cells were preincubated in a 1% sucrose solution. This increase in uptake rate was eliminated if certain tris buffers were included in the preincubation solution while other buffers had little effect. Calcium could reverse the effect of the inhibitory buffers only if the buffer and calcium were present together from the beginning of the preincubation period. It was the amine group of the inhibitory buffers which was responsible for the inhibition. Preincubation in a complete culture medium (EM Linsmaier, F Skoog 1965 Physiol Plant 18: 100-127) led to minimal changes in L-leucine uptake rate over a 10 hour preincubation period indicating that the uptake rate was stabilized by this medium. The complete medium stabilized the L-leucine uptake rate as a result of its ionic composition and not because of its osmolarity. Most of the increased uptake rate observed after preincubation in a 1% sucrose solution could be inhibited by 2,4-dinitrophenol or carbonyl cyanide m-chlorophenyl hydrazone, or high concentrations of L-phenylalanine or L-leucine. Therefore much of the increase could be accounted for by an increase in active transport of L-leucine.Increases in the rate of solute uptake have been induced in plant cells and tissues by a procedure of washing and preincubation (8,11,15,17,18). This effect has been observed using a number of species and for a broad range ofsubstrates: phosphate, potassium, chloride, glycine, glucose, and guanosine monophosphate (11); sulfate (10); L-serine (18); malate, glycerate-3-P, uracil, and several amino acids (8) (2,7,8,10,18). However, other researchers have demonstrated that an enhanced uptake rate can be induced without the addition of calcium to the preincubation solution (6,11,15). Transport workers also differ in their use of pH buffers in preincubation and incubation solutions. Some routinely employ pH buffers (2,7,8,10,15,18) while others do not (11,13,14, 19 nally isolated from pith, were maintained in LS medium3 as previously described (3). Subculturing was performed every 7 d by adding 50 ml of fresh LS medium to a culture flask and then dividing this suspension between two 125-ml Erlenmeyer flasks. Experiments were conducted on the 3rd d after subculturing near the end of the exponential growth phase (4).Uptake Assay. Under aseptic conditions, three or four flasks of cultured cells were combined, poured through a screen basket (mesh size of 1.5 mm) to remove clumps, and collected by centrifugation (161Og for 1 min). Two to 3 ml of cells were transferred to 50-ml tubes. The cells were washed three times by resuspending the cells in about 50 ml ofthe appropriate solution, shaking gently by hand for 2 min, letting the cells settle for about 4 min, and decanting the wash solution. The same solution, except where noted, was used for washing, preincubating, and measuring uptake except, L-leucine was presen...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

“…Transport workers also differ in their use of pH buffers in preincubation and incubation solutions. Some routinely employ pH buffers (2,7,8,10,15,18) while others do not (11,13,14,19). Reinhold's laboratory initially employed pH buffers (17), but because buffers were shown to influence the amino acid uptake process, they discontinued the use of buffers (1,16).…”

mentioning

confidence: 99%

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Amino Acid Transport in Suspension-Cultured Plant Cells

Schneegurt

McDaniel²

1986

Plant Physiol.

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Regulation by sulfhydryl groups of glyceollin accumulation in soybean hypocotyls

Stossel

1984

Planta

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Hypocotyls of 5-d-old etiolated soybean seedlings (Glycine max (L.) Merr. cv. Altona) were treated with (a) dithiothreitol (DTT) or one of the sulfhydryl-binding reagents N-ethylmaleimide (NEM), p-hydroxymercuribenzoate (PMB) und p-chloromercuribenzene sulfonic acid (PMBS), (b) one of the sulfhydryl reagents in combination with DTT, (c) sulfhydryl reagent subsequent to treatment with DTT, and (d) PMBS followed by DTT. Glyceollin was extracted 24 and 48 h after initiation of treatment. The order of decreasing glyceollin-eliciting activity was PMBS≫DTT>PMB≧NEM. Elicitor effectiveness of sulfhydryl reagents and their reactivity with either L-cysteine or sulfhydryl groups in soybean hypocotyls were not strictly correlated. Mixtures of sulfhydryl reagent and DTT, pretreatment of hypocotyls with DTT and subsequent application of either PMB or PMBS, as well as application of PMBS prior to DTT induced less glyceollin than sulfhydryl reagents alone. In contrast, such pretreatment did not appreciably alter glyceollin accumulation elicited by NEM. The results indicate that glyceollin synthesis can be regulated by interaction with sulfhydryl groups located mainly at the outer surface of the plasmalemma.

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