Sucrose Metabolism in Netted Muskmelon Fruit during Development

Lingle, Sarah E.; Dunlap, James R.

doi:10.1104/pp.84.2.386

Cited by 130 publications

(108 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thus, the function of the neutral invertase in muskmelon fruit seems to be different from that of the neutral (or alkaline) invertase in the above mentioned species. In addition, the rapid decline in activity of acid invertase during the development of the fruit supports the suggestion made by other investigators that a decrease in acid invertase activity is a prerequisite for the accumulation of sucrose in muskmelon fruits (5,10,16,18). Both acid and neutral types of soluble invertase were adsorbed to a DEAE-cellulose anion-exchange column but they were eluted at different concentrations of NaCl (Fig.…”

Section: Discussionsupporting

confidence: 66%

“…4). Moreover, we detected relatively higher activity of the neutral invertase in the mesocarp of immature muskmelon fruit as compared that reported by others (5,10). The data showed little change from 14 to 24 DAA (Figs.…”

Section: Discussionsupporting

confidence: 64%

“…Acid invertase activity was very high in immature fruits (more than 30 Amol h-' [g fresh weight]-'), and it declined rapidly and concomitantly with the accumulation of sucrose, as the fruit matured (5,10). In addition, neutral invertase activity is also substantial (about 15 gmol h-' [g fresh weight]-') in immature fruits and declines in parallel with the decline in acid invertase activity during the development of the fruit (10). By contrast, neutral (alkaline) invertases of some other plants are found in mature tissues where they regulate sucrose metabolism but are not found in immature tissues (4,7,13,17).…”

Section: Plant Materialsmentioning

confidence: 99%

“…Acid invertase (5, 10,16,18) and neutral invertase (5,10) have been detected in the mesocarp of the muskmelon (Cucumis melo L.). Acid invertase activity was very high in immature fruits (more than 30 Amol h-' [g fresh weight]-'), and it declined rapidly and concomitantly with the accumulation of sucrose, as the fruit matured (5,10). In addition, neutral invertase activity is also substantial (about 15 gmol h-' [g fresh weight]-') in immature fruits and declines in parallel with the decline in acid invertase activity during the development of the fruit (10).…”

Section: Plant Materialsmentioning

confidence: 99%

See 3 more Smart Citations

Acid and Neutral Invertases in the Mesocarp of Developing Muskmelon (Cucumis melo L. cv Prince) Fruit

Ranwala¹,

Iwanami²,

Masuda³

1991

Plant Physiol.

View full text Add to dashboard Cite

Acid and neutral invertases were found in the mesocarp of developing muskmelon (Cucumis melo L. cv Prince) fruit and the activities of these enzymes declined with maturation of the fruit, concomitantly with the accumulation of sucrose. Neutral invertase was only present in the soluble fraction and acid invertase was present in both the soluble and cell-wall fractions. The cell-wall fraction contained three types of acid invertase: a NaCI-released invertase; an EDTA-released invertase, and a tightly bound invertase that still remained on the cell wall after treatment with NaCI and EDTA. The soluble acid and neutral invertases could be separated from one another by chromatography on DEAE-cellulose and they exhibited clear differences in their properties, namely, in their pH optima, substrate specificity, Km values for sucrose, and inhibition by metal ions. The EDTA-released invertase and the soluble acid invertase were similar with regard to their chromatographic behavior on DEAE-cellulose, but the NaCIreleased invertase was different because it was adsorbed to a column of CM-cellulose. The soluble acid invertase and two cellwall bound invertases had very similar characteristics with regard to optimal pH and temperature, Km value for sucrose, and substrate specificity.

show abstract

Section: Discussionsupporting

confidence: 66%

Section: Discussionsupporting

confidence: 64%

Section: Plant Materialsmentioning

confidence: 99%

Section: Plant Materialsmentioning

confidence: 99%

See 2 more Smart Citations

Acid and Neutral Invertases in the Mesocarp of Developing Muskmelon (Cucumis melo L. cv Prince) Fruit

Ranwala¹,

Iwanami²,

Masuda³

1991

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…The presence of sucrosephosphate synthase in many storage organs (4,6,10,12,16) suggests that some sucrose may be resynthesized using this nonreversible pathway.…”

Section: Introductionmentioning

confidence: 99%

Sugar Content and Activity of Sucrose Metabolism Enzymes in Milled Rice Grain

Smyth¹,

Prescott²

1989

Plant Physiol.

View full text Add to dashboard Cite

Most rice (Oryza sativa L.) culfivars grown in the United States were selected for endosperm starch properties and not soluble sugar content. The minor pool of soluble sugar may affect the qualities of rice as a food. Some cultivar variation in soluble sugar content was detected in milled grain, essentially the starchy endosperm, of long grain varieties. Milled grain of cultivars Lemont and Texmati had a soluble sugar content of 0.21 and 0.35% (w/w), respectively, on a fresh weight basis. The dorsal portion of the milled grain contained the greatest amount of soluble sugar, approximately tenfold the amount found in the central core of the grain. Extracts of the milled grain contained sucrosephosphate synthase (EC 2.4.1.14) and sucrose synthase (EC 2.4.1.13) activities, which were separated by anion exchange chromatography. The presence of sucrose-phosphate synthase in the rice endosperm suggested a mechanism for sucrose accumulation which might be involved in carbon partitioning during grain development.Mature storage tissues such as cereal endosperm consist primarily of starch and a minor pool of soluble sugar (9,14,16). Consequently, the major fate of translocated photosynthate entering the developing endosperm is to be metabolized by invertase or sucrose synthase into precursors for starch biosynthesis. The endosperm sucrose pool represents an alternative storage form for incoming photosynthate. It is unclear whether endosperm sucrose accumulation depends on transport of unmetabolized sucrose into the endosperm cell, or whether resynthesis of sucrose occurs from a pool of hexoses and nucleotide sugars common to the starch biosynthesis pathway (7).Resynthesis of sucrose might be catalyzed by sucrose synthase, or by a combination of sucrose-phosphate synthase and sucrose phosphatase activities (7). The presence of sucrosephosphate synthase in many storage organs (4,6,10,12,16) suggests that some sucrose may be resynthesized using this nonreversible pathway.Endosperm mutations are known which increase soluble sugar content of cereal grain (13). Samples of rough rice grown in Beaumont, TX, were dehulled, and the whole caryopsis used for microscopy. Sugar Content of Milled GrainSamples (100 mg) of milled grain flour were extracted with 2.5 mL of 70% (v/v) ethanol as described previously (16). Triplicate aliquots of the extracts were analyzed for sucrose using a resorcinol reagent (8,16), and for soluble reducing sugar using the neocuproine technique relative to standards of glucose (2).Milled grain of cultivar Starbonnet was sliced using a scalpel. The top portion and bottom portion averaged 31 and 37% (w/w), respectively, of the total milled grain weight. The middle portion of the grain was sliced into dorsal, lateral, ventral, and core sections. Portions of the milled grain were ground into flour using a mortar and pestle. Flour samples (25 to 35 mg) were extracted twice at 80°C for 10 min with a total volume of 1.2 mL of 70% (v/v) ethanol. Sucrose and soluble reducing sugar content were measured as indi...

show abstract