Soluble Acid Invertase Activity Research Articles

Changes in content of indole-3-acetic acid and in activities of sucrose-metabolizing enzymes during fruit growth in eggplant ( Solanum melongena L.)

Summary Changes in the content of endogenous indole-3-acetic acid (IAA) and in activities of sucrose-metabolizing enzymes during fruit set were investigated in eggplant (Solanum melongena L.). When fruit growth was stimulated by pollination or treatment with 4-chlorophenoxyacetic acid (4-CPA), IAA content increased during fruit set. Intra- and extra-cellular fractions were separated by washing fruit tissue segments with 0.5 mol · L−1 NaCl. Invertase from both fractions had an optimum at pH 5. The activity in the intra-cellular fraction (soluble acid invertase) was much higher than that in the extra-cellular fraction (cell-wall-bound acid invertase). However, fruit mass and IAA content did not increase in unpollinated fruit. Activities of all the sucrose-metabolizing enzymes also increased during fruit set, when fruits were treated by pollination or 4-CPA. Time courses of change in activity of soluble acid invertase and sucrose phosphate synthase (SPS) were quite similar to that of the relative growth rate of the fruit. In contrast, changes in activity of cell-wall-bound acid invertase and sucrose synthase (SS) were not clearly associated with fruit growth. The increase in activity of soluble acid invertase was accompanied by the increase in endogenous IAA content. These results suggest a possible involvement of IAA in the synthesis of soluble acid invertase that may induce fruit growth.

The Role of Indole-3-Acetic Acid and Acid Invertase in the Development of Melon (Cucumis melo L. cv. Prince) Fruit

Changes in indole-3-acetic acid (IAA) contents of melon (Cucumis melo L. cv. Prince) fruits were plotted during their developmental stages. The IAA content of mesocarp was almost constant during fruit development but that of seeds increased for 20 days after pollination, then decreased significantly. Hence, seeds contained much more IAA than the mesocarp throughout fruit development. The seeds may effuse IAA to the enlarging mesocarp, so that its IAA content remain constant.Exogenous application of IAA on the activities of sucrose-metabolizing enzymes, which are closely related to the sink activity of fruits, stimulated activities of the cell wallbound and soluble acid invertases, but not those of sucrose-and sucrose phosphate synthases. Thus, endogenous IAA may play an important role in the induction of cell wallbound and soluble acid invertases.We postulate that exported IAA from seeds to mesocarp stimulate cell wallbound and soluble acid invertase activities, thereby strengthening its sink activity during fruit development.

Properties of invertases in mycelium of Hymenoscyphus ericae and in endomycorrhizal association with cranberry seedlings

The properties of extracellular, soluble and insoluble invertases in mycelium of Hymenoscyphus ericae an ericoid mycorrhizal fungus, were investigated. Soluble and insoluble acid invertases were more active in sucrose- compared with glucose-grown mycelium, whereas extracellular invertase activities were similar in both glucose- and sucrose-grown cultures. Acid (pH 5·5) and alkaline (pH 9·0) invertases were detected in soluble and insoluble fractions but extracellular activity was predominantly acid (pH 5·5). Insoluble alkaline invertase was released completely by freeze-thawing. Freeze-thawing and Triton X-100 released similar proportions of acid invertase from the wall (42 and 31% respectively). The K m values varied from 9·1 m m (extracellular acid invertase) to 139·3 m m sucrose (soluble alkaline invertase). Fructose inhibited soluble alkaline invertase completely but it competitively inhibited soluble acid invertase. Increased soluble acid invertase activity was demonstrated in endomycorrhizas compared with uninoculated roots of cranberry.

Carbohydrate content and the activities of sucrose synthase, sucrose phosphate synthase and acid invertase in different tomato cultivars during fruit development

Changes in carbohydrate content and activities of related enzymes of the developing fruits of three tomato cultivars ( Lycopersicon esculentum Mill. cv. Momotaro, Lady First and Minicarol) were followed throughout fruit development. In all the cultivars fructose and glucose in nearly equal amounts, were the predominant sugars. Sucrose was present in trace quantities but the small fruited cultivar Minicarol accumulated higher levels of sucrose than the other two large fruited cultivars. The activity of soluble acid invertase (EC3.2.1.26) was highest in ripe fruits (55 days of anthesis) but in the case of cell wall-bound acid invertase, it was less and almost constant throughout development. Sucrose synthase (EC2.4.1.13) activity was highest in the young fruit and declined sharply with development; ‘Minicarol’ had the highest activity. Sucrose phosphate synthase (EC2.4.1.14) activity remained relatively constant throughout development in all cultivars studied. A highly significant positive correlation was found with sucrose accumulation in the case of sucrose synthase but there was a negative correlation with acid invertase activity and none with sucrose phosphate synthase. Therefore, it appeared that acid invertase and sucrose synthase were involved in the metabolism of sucrose during tomato fruit development and a constant sucrose phosphate synthase activity was not required for sucrose accumulation. Furthermore, the small fruited tomatoes had a higher amount of reducing sugars and sucrose, and higher sucrose synthase and sucrose phosphate synthase activities compared with large fruited types. The results are discussed in terms of the metabolic events associated with soluble sugar accumulation.

Induction of Male Sterility in Wheat by Meiotic-Stage Water Deficit Is Preceded by a Decline in Invertase Activity and Changes in Carbohydrate Metabolism in Anthers.

Water deficit during meiosis in pollen mother cells of wheat (Triticum aestivum L.) induces male sterility, which can reduce grain set by 40 to 50%. In plants stressed during meiosis and then rewatered, division of pollen mother cells proceeds normally but subsequent pollen development is arrested 3 or 4 d later. An inhibition of starch accumulation within the pollen grain suggested that an alteration in carbohydrate metabolism or assimilate supply may be involved in pollen abortion. We measured levels of various carbohydrates and activities of key enzymes of Suc metabolism and starch synthesis at different stages of pollen development in anthers collected from well-watered and water-stressed plants. Compared to controls, soluble sugars increased in anthers stressed during meiosis, then decreased at later poststress stages. Sucrose and myoinositol accounted for part of the sugar accumulation. The activity of soluble acid invertase declined 4-fold during the stress period and never recovered thereafter. Sucrose synthase activity during starch accumulation in pollen was also lower in the anthers of plants stressed at meiosis. Stress had little negative effect on the activities of ADP-glucose pyrophosphorylase or soluble and granule-bound starch synthase during starch accumulation in pollen, although at the earlier stages, ADP-glucose pyrophosphorylase activity in stressed anthers was slightly lower compared to controls. The results suggest that carbohydrate starvation per se and inhibition of the enzymes of starch synthesis probably were not responsible for the stress-induced pollen abortion. Instead, an inability to metabolize incoming sucrose to hexoses may be involved in this developmental lesion.

Rhythmic growth and carbon allocation in Quercus robur. Sucrose metabolizing enzymes in leaves

The high sucrose phosphate synthase (SPS) capacity and the low soluble acid invertase activity of mature leaves of the first flush of leaves remained stable during second flush development. Conversely, fluctuations of sucrose synthase (SS) activity were in parallel with the sucrose requirement of the second flush. Sucrose synthase activity (synthesis direction) in first flush leaves could increase in ‘response’ to sink demand constituted by the second flush growth. Only the ptotosynthates provided by flush mature leaves were translocated for a current flush, while the starch content of these leaves remained stable. After their emergence, second flush leaves showed an increase in SPS and SS (Synthetic direction) activities. The high sucrose synthesis in second flush leaves was used for leaf expansion. When young leaves were 30% fully expanded (stage II20), SPS activity showed little change whereas SS activity declined rapidly toward and after full leaf expansion. The starch accumulation in the young leaves occured simultaneously with their expansion. Developing leaves showed a high level of acid invertase activity until maximum leaf expansion (stage II1). In first and second flush leaves, changes in acid invertase activity correlated positively with changes in reducing sugar concentrations. Alkaline invertase and sucrose synthase (cleavage direction) activities showed similar changes with low values when compared with those of acid invertase activity, especially in second flush leaves. The present results suggest that soluble acid invertase was the primary enzyme responsible for sucrose catabolism in the expanding common oak leaf.

Changes in Carbohydrate, Protein and Chlorophyll Content, and Enzyme Activity During the Switch from Uredinio‐ to Teliospore Sporulation in the Bean‐rust Fungus Uromyces appendiculatus (Pers.) Link

AbstractChanges in carbohydrate metabolism and senescence during the development of the bean‐rust fungus Uromyces appendiculatus (Pers.) Link were investigated. At different stages of uredinio‐ and teliospore production, samples were taken from infected and non‐infected bean leaves, beginnig with the flecking stage. The unsoluble‐carbohydrate, sucrose, glucose and fructose content, as well as fluctuations in soluble acidinvertase activity and parameters of leaf senescence were determined.While fructose remained constant without significant differences between infected leaf sections and the control, differences in the other carbohydrates and in soluble‐invertase activity could be detected. Parameters indicating leaf senescence were retarded and decreased with age, except for peroxidase activity, which was enhanced and increasd with age in infected tissue to a higher degree than in the control. The results are discussed in relation to their significance for fungal development.

Effects of Guaianolide derivative I on fibre initiation and elongation in Gossypium arboreum L. in relation to adverse effects of cool temperature

Cotton ovules collected during late September with prevalent night cool temperature (15°C), cultured at 30°C/15°C i.e. cycling temperatures in Beasley and Ting medium had very few epidermal cells showing bulging. Supplementing cultures with guaianolide derivative I (E-13 methyldehydrocostus lactone) promoted fibre initiation. At—1 day preanthesis (DPA), IAA oxidase activity declined in guaianolide-treated cultures but increased during the elongation phase and was enhanced during the secondary wall thickening phase. However, o-diphenol oxidase activity was adversely affected during the fibre initiation phase. The activities of all the other enzymes studied viz. acid invertase, phenylalanine ammonia lyase, β-glucosidase and IAA oxidase increased, except β-galactosidase, during the later phase in comparison with the controls. The present study indicates that guaianolide derivative I triggers early initiation and promotes fibre elongation by regulatin o-diphenols and IAA-oxidation levels, which in turn check wall loosening. Considerable enhancement in the soluble acid invertase activity by this compound suggests its role in apoplastic sucrose hydrolysis, thereby preventing its accumulation.

Expression of Soluble and Wall-bound Acid Invertases in Different Tissue of Lilium longiflorum Flower Buds

In mature Lilium longiflorum flower buds, anther and stigma had the highest soluble acid invertase activity [3.29 and 2.31 μmol of reducing sugars (RS)/min per gram of fresh weight (FW), respectively] compared to style, ovary, petal, and filament with activities of 1.52, 1.08, 0.99 and 0.98 μmol RS/min per gram of FW, respectively. DEAE-sephacel chromatography revealed that invertase activity in petal, ovary, style, and stigma was composed exclusively of invertase II and III isoforms. Anther invertase was mainly invertase I with small amounts of invertase II and III. Filament tissue mainly had invertase II and III isoforms with a small amount of invertase I. Wall-bound invertases were extracted with 1.0 m NaCl. Anthers had the highest wall-bound invertase activity (4.42 μmol RS/min per gram of FW) followed by stigma (0.42 μmol RS/min per gram of FW). Other tissues had low wall-bound invertase activity (<0.1 μmol RS/min per gram FW). For further purification, the binding of soluble invertases to nine different reactive dyes was investigated. Invertase I was bound to Reactive Green 5, Reactive Green 19, and Reactive Red 120 columns and was eluted with 0.5 m NaCl, resulting in increase in specific activity ≈10-fold with ≈70% recovery. Invertase II and III bound only to Reactive Red 120. Elution with 0.5 m NaCl resulted in an ≈6-fold increase in specific activity.

PCR-generated molecular markers for the invertase gene and sucrose accumulation in tomato

The green-fruited tomato species, Lycopersicon hirsutum, unlike the domesticated red-fruited species, L. esculentum, accumulates sucrose during the final stages of fruit development, concomitant with the loss of soluble acid invertase activity. In order to study the genetic linkage of sucrose accumulation to the invertase gene, part of the invertase gene from L. hirsutum was cloned, sequenced and the sequence compared with the invertase sequence of the red-fruited L. esculentum. Several base changes were found in the coding region of the two invertase genes. Based on these base -pair differences, we developed a species-specific PCR assay capable of determining, in a single PCR reaction, the origin of the invertase gene in segregating seedlings of an interspecific cross. Our results indicate that the invertase gene is genetically linked to sucrose accumulation in the green-fruited L. hirsutum.

Synthesis and Storage of Sucrose in Relation to Activities of Its Metabolizing Enzymes in Sugarcane Cultivars Differing in Maturity

Metabolic changes in the contents of sucrose and hexoses in relation to the activities of invertase, sucrose synthase and sucrose-phosphate synthase in early (CoJ 64) and late (Co 1148) maturing cultivars of sugarcane have been studied. During early stages of cane growth, lower activities of sucrose synthase and sucrose-phosphate synthase in leaf blade In CoJ 64 over Co 1148 were observed. However, sucrose content in sheath/blade was higher in CoJ 64 than in Co 1148. With the advancing age, the activity of soluble acid invertase (pH 5.4) in stem declined more rapidly in CoJ 64. This resulted in building up of high ratio of sucroselinvert sugars in stem tissue of this cultivar. Feeding uniformly-labelled sucrose and glucose to the cut discs of leaf sheath resulted in higher uptake of 14C in CoJ 64 than in Co 1148. Uptake by stem tissue discs of 14C from sucrose was less than that from hexoses. Based on these results, it is suggested that (i) the rapid fall in the activity of soluble acid invertase in stem concomitant with fast accumulation of sucrose in this tissue is an index of early maturity of the cane, and (ii) high content of sucrose in sheath is a reflection of an efficient translocation of this sugar in early maturing cultivars.

Differences in sucrose metabolism relative to accumulation of bird‐deterrent sucrose levels in fruits of wild and domestic Vaccinium species

We examined variability in sucrose levels and metabolism in ripe fruits of wild and domestic Vaccinium species and in developing fruits of cultivated blueberry (V. ashei and V. corymbosum). The objective was to determine if sufficient variability for fruit sucrose accumulation was present in existing populations to warrant attempts to breed for high‐sucrose fruit, which potentially would be less subject to bird predation. Threefold differences in fruit sucrose concentration were found among Vaccinium species, ranging from 19 to 24 mg (g fresh weight)−1 in V. stamineum and V. arboreum to approximately 7 mg (g fresh weight)−1 in cultivated blueberry (V. ashei and V. corymbosum) and V. darrowi. Hexose levels were similar among species, ranging from 90 to 110 mg (g fresh weight)–1, and glucose and fructose were present in equal amounts. Soluble acid invertase (EC 3.2.1.26) activity was negatively correlated with fruit sucrose concentration. There was no apparent correlation between fruit sugar concentration and either sucrose synthase (EC 2.4.1.13) or sucrose phosphate synthase (EC 2.4.1.14) activities, both of which were low for all species studied. Developmental increases in fruit sugar levels of cultivated blueberry followed a pattern similar to that observed in fruit fresh weight accumulation. Hexose concentrations ranged from 6 to 30 mg (g fresh weight)−1 during the first 60 days after anthesis. Between 60 days and fruit ripening (80 days), hexose levels rose from 30 to 80 mg (g fresh weight)−1. Sucrose was not detected in fruits until ripening, when low levels were found. Insoluble acid invertase activity was relatively high early in fruit development, decreasing as soluble acid invertase activity increased. Between 60 days and fruit ripening, soluble acid invertase activity increased from 3 to 55 μmol (g fresh weight)–1 h–1. Both sucrose synthase and sucrose phosphate synthase activities were low throughout development. The extent of sucrose accumulation in fruits and the degree of variability for this trait among Vaccinium species support the feasibility of developing high sucrose fruits, which would be a potentially valuable addition to current strategies of minimizing crop losses to birds.

782 PB 424 INVERTASE ACTIVITY AND CARBOHYDRATE COMPOSITION IN DEVELOPING ANTIRRHINUM MAJUS L. FLOWERS

The relationship between the activity of soluble acid invertase and metabolism of soluble carbohydrates was investigated in snapdragon flowers. Flowers were harvested at three different developmental stages, and at four different dates. Soluble carbohydrates were extracted and analyzed by HPLC; invertase activity was determined in crude enzyme extracts. Sucrose concentration slowly increased throughout flower development from a closed bud to a fully open flower. Fructose and glucose concentration were relatively lower at the bud stage, increased during petal elongation, then slightly decreased at flower maturity. Mannitol concentration showed little change during flower development. An unknown compound increased in concentration during petal elongation and decreased at maturity. For all harvest dates, the specific activity of acid invertase increased with flower development. These results show a positive correlation of invertase activity and hexose sugars accumulation. It is possible that at maturity sugars are metabolized at a faster rate than produced, causing a slight decline in hexose sugars.

746 PB 102 DIFFERENCES IN SUCROSE METABOLISM RELATIVE TO ACCUMULATION OF BIRD-DETERRENT SUCROSE LEVELS IN FRUIT OF VACCINIUM SPECIES

Variability in sucrose levels and metabolism in ripe fruit of several Vaccinium species were examined. The objective was to determine if sufficient variability for fruit sucrose accumulation was present in existing populations to warrant attempts to breed for high-sucrose fruit, which potentially would be less subject to bird predation. Three-fold differences in fruit sucrose concentration were found among species, ranging from 19 to 24 mg·(g fw)-1 in V. stamineum and V. arboreum to about 7 mg·(g fw)-1 in cultivated blueberry (V. ashei and V. corymbosum) and V. darrowi. Soluble acid invertase activity was negatively correlated with fruit sucrose concentration. There was no apparent correlation between fruit sugar concentration and either sucrose phosphate synthase or sucrose synthase activities, both of which were low for all species studied. The degree of variability in fruit sucrose accumulation among Vaccinium species supports the feasibility of developing high sucrose fruit, which would be a potentially valuable addition to current strategies of minimizing crop losses to birds.

Sucrose synthase, invertases, and sugars in growing asparagus spears

Abstract Asparagus (Asparagus officinalisL.) spear tips lose sucrose rapidly after harvest and this probably contributes to spears’ short postharvest life. As the first step towards controlling this loss of sucrose and possibly improving postharvest life, the activities of sucrose‐cleaving enzymes, and levels of sugars were measured in tips and 3 cm sections of spears from tip to butt. Sucrose was the major sugar in tips but not in the rest of the spear. Glucose and fructose were almost equimolar throughout the spear and increased fivefold from tip to butt. Fructose was always slightly more abundant than glucose. Sucrose synthase, bound acid invertase, and neutral invertase activities were similar in both tips and spear sections. Soluble acid invertase activity in the middle section of the spear was 4—5 times that of tips and butts. Sugar composition and enzyme activities in spear sections and tips were not closely correlated.

Manipulation Through Liquid Culture in the Contents of Sucrose and Glutamine and Their Transformation to Starch and Protein in Wheat Grain

Detached ears of wheat were cultured in liquid medium manipulated for sucrose and glutamine contents, and the accumulation of starch and protein in relation to the activities of sucrose cleaving—, ammonia assimilating—, and transaminating enzymes was studied in the grain. With an increase in the concentrations of sucrose from 44 to 176 mM and glutamine from 6.4 to 25.7 mM (keeping their ratio at a constant value of 7:1), the contents of starch and protein increased in the grains. However, when the grains were cultured in the medium containing 8.5 to 34 mM glutamine and a fixed concentration of 117 mM sucrose, there was a gradual increase in protein and decrease in starch content in the grain. By such manipulation in the liquid medium, the content of free amino acids also increased in the grain up to 12 days culturing. Amongst sucrose cleaving enzymes, the activities of sucrose-UDP glucosyl transferase and soluble alkaline invertase were much lower than the activity of soluble acid invertase. At high concentration (34 mM) of glutamine in the medium, containing 117 mM sucrose, there was drastic decrease in the activities of soluble acid invertase and UDPG pyrophosphorylase but the activities of ADPG pyrophosphorylase, alkaline inorganic pyrophosphatase, glutamate dehydrogenase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase increased in the grain with increase in glutamine concentration in the culture medium. Evidently, an increase in the level of amino nitrogen, coupled with an optimum sucrose concentration in the grain raised through liquid culturing enhances the conversion of sucrose to protein at the cost of starch accumulation in wheat.

Activity of sucrose synthase and soluble acid invertase following germination of pinyon (Pinusedulis) seeds

The developmental pattern and relative activities of sucrose synthase (EC 2.4.1.13) and soluble acid invertase (EC 3.2.1.26), and the associated contents of sucrose and hexoses, were analyzed in the cotyledons, hypocotyl, and radicle of pinyon (Pinusedulis Engelm.) seedlings following radicle emergence. Sucrose synthase activity did not appear to be correlated with organ growth, but showed a close association with sucrose content. Conversely, there was a high degree of correlation between soluble acid invertase activity and growth of the various organs. Hexose content also was correlated with the level of invertase activity. Thus, soluble acid invertase appeared to be directly involved in providing respiratory and biosynthetic substrates in growing organs, while the role of sucrose synthase was less clear, being more active in tissues that are involved in sucrose import and transport and possibly sucrose to starch conversion.

Levels and Role of Sucrose Synthase, Sucrose-phosphate Synthase, and Acid Invertase in Sucrose Accumulation in Fruit of Asian Pear

Soluble sugar content and activities of the sucrose-metabolizing enzymes sucrose synthase (SS) (EC 2.4.1.13), sucrose-phosphate synthase (SPS) (EC 2.4.1.14), and acid invertase (EC 2.4.1.26) were analyzed in the pericarp of fruit from pear cultivars that differed in their potential to accumulate sucrose to identify key enzymes involved in sucrose accumulation in Asian pears. The Japanese pear `Chojuro' [Pyrus pyrifolia (Burro. f.) Nakai] was characterized as a high-sucrose-accumulating type based on the analysis of mature fruit, while the Chinese pear `Yali' (P. bretschneideri Rehd.) was a low-sucrose-accumulating type throughout all developmental stages. The activity of SS and SPS in `Chojuro' increased during maturation concomitant with sucrose accumulation, whereas the activity of these enzymes in `Yali' did not increase during maturation. The activity of SS and SPS in the former were seven and four times, respectively, higher than those in the latter at the mature stage. Further, among 23 pear cultivars, SS activity was closely correlated with sucrose content, while SPS activity was weakly correlated. Soluble acid invertase activity in `Chojuro' and `Yali' decreased with fruit maturation, but the relationships between soluble invertase activity and sucrose content were not significant. The results indicate that SS and SPS are important determinants of sucrose accumulation in Asian pear fruit and that a decrease of soluble acid invertase activity is not absolutely required for sucrose accumulation.

Effect of heat stress on the growth, root sugars, acid invertase and protein profile of pepper seedlings following transplanting

The development of pepper transplants is sensitive to the prevailing temperature in the field. High temperatures immediately after transplanting pepper seedlings delay their development in the field. During nine days of post-transplanting heat stress (30/25°C or 35/25°C, day/night temperature regimes), root and shoot growth were inhibited compared to the control transplants (25/18°C) with a significant decline in total protein and soluble acid invertase activity in the roots of the heat stressed plants. Acid invertase activity was less sensitive to the heat stress in the leaves than in the roots. A significant reduction in the root invertase activity occurred as early as two days after the beginning of the stress. Transplanting caused a 72% inhibition in the carbon allocation to the roots, compared with the non-transplanted seedlings. Exposure to heat after transplanting did not further reduce carbon allocation to the roots. The protein profile on SDS-PAGE from leaves shows that during the heat stress, so...

Soluble and wall-bound invertases in strawberry fruit

The relationship between the changes in soluble neutral sugar content and the changes in the activities of soluble and wall-bound invertases was investigated at various stages throughout the development of strawberry ( Fragaria × ananassa Duch. var. Hókowase) fruits. Glucose, fructose and sucrose concentrations were relatively low at the immature stage and, thereafter increased during development. The two hexose sugar concentrations were substantially higher than the sucrose concentration at all stages. Soluble acid invertase activity increased parallel to the accumulation of hexose sugars. In contrast, the activities of two types of wall-bound invertase (the NaCl-released and ethylenediaminetetraacetic acid (EDTA)-released ones) were relatively high at the immature stage and then declined steadily during the ripening of the fruit. Soluble and wall bound invertases exhibited similar enzymological properties with regard to optimal pH and temperature, the K m-value forsucrose and the substrate specificity. However, they exhibited different degrees of inhibition by Ag +, Hg 2+ and Mn 2+ ions.