Cucurbita Ficifolia Research Articles

Egg-yolk protein by-product as a source of ACE-inhibitory peptides obtained with using unconventional proteinase from Asian pumpkin (Cucurbita ficifolia).

Peptides with specific biological activity can be used in pharmaceutical, cosmetic or food industries. Because of their potential role as physiological modulators, as well as theirhigh safety profile, they can be used as natural pharmacological compounds or functional food ingredients. The development of biotechnological solutions to obtain peptides with desired biological activity is already in progress. Studies in this area are focused on using unconventional highly specific enzymes and more efficient methods developed to conduct food process technologies. Natural peptides have many advantages. They are mainly toxicologically safe, have wide spectra of therapeutic actions, exhibit less side effects compared to synthetic drugs and are more efficiently absorbed in the intestinal tract. The complexity of operation of large scale technologies and high cost of purification techniques are limiting factors to the commercialization of food-derived bioactive peptides. Research on the isolation of bioactive peptides in order to reduce the processing time and costs is continuously developing. Bioactive peptides can also be released from protein by-products of the food industry, which reduce the substrate expense and production cost as well as provide the added advantage of an efficient waste disposal. Moreover, proteins as precursors of food-derived peptides are well-tolerated by the human body and therefore their application in drug development may reduce costs and duration of toxicological studies during research, development and clinical trials.

The Evaluation of Dipeptidyl Peptidase (DPP)-IV, α-Glucosidase and Angiotensin Converting Enzyme (ACE) Inhibitory Activities of Whey Proteins Hydrolyzed with Serine Protease Isolated from Asian Pumpkin (Cucurbita ficifolia).

In the present study, whey protein concentrate (WPC-80) and β-lactoglobulin were hydrolyzed with a noncommercial serine protease isolated from Asian pumpkin (Cucurbita ficifolia). Hydrolysates were further fractionated by ultrafiltration using membranes with cut-offs equal 3 and 10 kDa. Peptide fractions of molecular weight lower than 3 and 3–10 kDa were further subjected to the RP-HPLC. Separated preparations were investigated for their potential as the natural inhibitors of dipeptidyl peptidase (DPP-IV), α-glucosidase and angiotensin converting enzyme (ACE). WPC-80 hydrolysate showed higher inhibitory activities against the three tested enzymes than β-lactoglobulin hydrolysate. Especially high biological activities were exhibited by peptide fractions of molecular weight lower than 3 kDa, with ACE IC50 <0.64 mg/mL and DPP-IV IC50 <0.55 mg/mL. This study suggests that peptides generated from whey proteins may support postprandial glycemia regulation and blood pressure maintenance, and could be used as functional food ingredients in the diet of patients with type 2 diabetes.

The sub/supra-optimal temperature-induced inhibition of photosynthesis and oxidative damage in cucumber leaves are alleviated by grafting onto figleaf gourd/luffa rootstocks.

Shoot-root communication is involved in plant stress responses, but its mechanism is largely unknown. To determine the role of roots in stress tolerance, cucumber (Cucumis sativus) shoots from plants with roots of their own or with figleaf gourd (Cucurbita ficifolia, a chilling-tolerant species) or luffa (Luffa cylindrica (L.) M. Roem., a heat-tolerant species) rootstocks were exposed to low (18/13°C), optimal (27/22°C) and high (36/31°C) temperatures, respectively. Grafting onto figleaf gourd and luffa rootstocks significantly alleviated chilling and heat-induced reductions, respectively, in biomass production and CO(2) assimilation capacity in the shoots, while levels of lipid peroxidation and protein oxidation were decreased. Figleaf gourd and luffa rootstocks upregulated a subset of stress-responsive genes involved in signal transduction (MAPK1 and RBOH), transcriptional regulation (MYB and MYC), protein protection (HSP45.9 and HSP70), the antioxidant response (Cu/Zn-SOD, cAPX and GR), and photosynthesis (RBCL, RBCS, RCA and FBPase) at low and high growth temperatures, respectively, and this was accompanied by increased activity of the encoded enzymes and reduced glutathione redox homeostasis in the leaves. Moreover, Heat Shock Protein 70 (HSP70) expression in cucumber leaves was strongly induced by the luffa rootstock at the high growth temperature but slightly induced by the figleaf gourd rootstock at low or high growth temperatures. These results indicate that rootstocks could induce significant changes in the transcripts of stress-responsive and defense-related genes, and the ROS scavenging activity via unknown signals, especially at stressful growth temperatures, and this is one of mechanisms involved in the grafting-induced stress tolerance.

Effects of Cucurbita ficifolia Intake on Type 2 Diabetes: Review of Current Evidences

Context: Type 2 diabetes mellitus (DM) is one of the most common chronic diseases worldwide. In recent years, Cucurbita ficifolia intake has been identified as one of the most widely used herbal medications in treatment of DM. Since previous studies have suggested the benefits of C. ficifolia intake in treatment of DM, we reviewed available literature concerning effects of C. ficifolia on Type 2 DM. Evidence Acquisition: Databases such as PubMed, Scopus, and Google scholar were searched. Key words included type 2 diabetes, blood glucose, hyperglycemia, insulin resistance, and Cucurbita. After removing irrelevant article, ten articles were reviewed. Results: Studies reported beneficial effects of C. ficifolia on serum insulin and glucose level. Some of the studies showed a correlation between low level of lipid profiles and plasma glucose and increase intake of C. ficifolia. Although the exact role of C. ficifolia intake on DM has not been identified, the benefits might be due to the effects of active compounds such as flavonoids, alkaloids, polyphenolic components, glutathione peroxidase, and superoxide dismutase. Conclusions: Cucurbita ficifolia intake might have useful effects on prevention and treatment of DM. Cucurbitaficifolia has beneficial effects on insulin sensitivity and risk factors of DM; however, due to the small number of available studies, more researches are needed in this field.

Acid phosphatases in seeds and developing of squash (Cucurbita ficifolia)

Changes in protein content and acid phosphatase activity were followed during germination (imbition through seedlings development) in extracts from cotyledons of squash (&lt;i&gt;Cucurbita ficifolia&lt;/i&gt;). It has been shown that the activity of acid phosphatase was initially low and than increased to a maximum after 6 days of imbition. Acid phosphates were isolated from cotyledons of seeds and from 6-, 10- and 22-days old seedlings by extraction the proteins with 0.1 M acetate buffer pH 5.1, precipitation with ethanol and by affinity chromatography on con A-Sepharose. Two glycoprotein enzymes AcPase Ba and AcPase Bb which differ in their affinity to immobilized con A were obtained. Both acid phosphatates retained the enzyme activity after binding to free con A. Rocket affinity electrophoresis of AcPase Ba and AcPase Bb, isolated from cotyledons of seeds and seedlings, revealed differences in their ability to bind to con A during seeds germination and seedling develop-ment indicating changes in their sugar component. Con A was found to activate both enzymes. The enzymes cross-reacted with monospecific antibodies raised against grass seed acid phosphatate Ba indicating an antigenic relationship between squash and grass acid phosphatases.

Immunologically related lectins from stems and roots of developing seedlings of Cucurbita ficifolia: purification and some properties of root and stem lectins

Hemagglutinating activity has been found in acetate extracts from roots and stems of squash seedlings (&lt;em&gt;Cucurbita ficifolia&lt;/em&gt;). The hemaglutinating activity changes during seeds germination and seedling development. Dot blot and Western blot techniques have shown that proteins from these vegetative tissues cross-reacted with antibodies raised against endogenous cotyledons lectin CLBa and Con A.Lectins were isolated from stems and roots of 6-day old seedlings by precipitation with ethanol, affinity chromatography on Con A-Sepharose, gel filtration on Bio-gel P100 and separated by electrophoresis on polyacrylamide gel. Three purified lectins (RLA&lt;sub&gt;1&lt;/sub&gt;, RLA&lt;sub&gt;2&lt;/sub&gt;, RLA&lt;sub&gt;3&lt;/sub&gt;) were obtained from roots and four from stems (SLA&lt;sub&gt;1&lt;/sub&gt;, SLA&lt;sub&gt;2&lt;/sub&gt;, SLA&lt;sub&gt;3&lt;/sub&gt;, SLA&lt;sub&gt;4&lt;/sub&gt;). The purified lectins from roots and stems agglutinated all human red blood cells, but sheep erythrocytes were most sensitive to agglutination. The hemagglutination of the root lectins RLA&lt;sub&gt;2&lt;/sub&gt; and RLA&lt;sub&gt;3&lt;/sub&gt; was inhibited by a very low concentration of arabinose, while RLA&lt;sub&gt;1&lt;/sub&gt;, of xylose and Ga1NAc. Arabinose and Xylose were also found to be the most effective inhibitors of all stem lectins.

Effect of Exogenous NaHS on Seed Germination and Physiological Characteristics of Cucurbita ficifolia Under NaHCO 3 Stress

Effect of Exogenous NaHS on Seed Germination and Physiological Characteristics of <i>Cucurbita ficifolia</i> Under NaHCO ₃ Stress

Effects of NaHCO&lt;sub&gt;3&lt;/sub&gt; Stress on the Growth and Physiological Indexes of Pumpkin Seedlings

Few studies have investigated the alkali-based salt resistance aspect of plants. Here, we used 2 pumpkin cultivars ('Cucurbita ficifolia Bouch.' and 'Chuandilong') to study the growth and physiological response mechanisms of pumpkin to different levels of NaHCO3 stress. After second true leaf development, pumpkin seedlings were treated with varying levels of NaHCO 3 stress (0, 30, 60 and 90 mmol/L) during sand culture. The chlorophyll content, electrolyte leakage, malondialdehyde (MDA) contents, proline contents, soluble sugar contents and superoxide dismutase (SOD) and peroxidase (POD) activities of both cultivars were investigated. Finally, the growth and physiological indexes of pumpkin seedlings under NaHCO3 stress were explored. The results showed that the chlorophyll a, chlorophyll b and total chlorophyll of both pumpkin seedlings increased with exposure to low NaHCO3 concentrations (0-30 mmol/L) and then decreased with exposure to 30-90 mmol/LNaHCO 3 and all reached their minimum values with exposure to 90 mmol/L NaHCO 3. Under the latter stress, the rate of decrease in total chlorophyll content of 'C. ficifolia Bouch.' was higher than that of 'Chuandilong'. However, electrolyte leakage, MDA content, proline content, soluble sugar content and SOD and POD activities increased with the escalation of NaHCO 3 concentration and peaked after exposure to 90 mmol/LNaHCO 3. The rates of increase in electrolyte leakage and MDA contents of 'C. ficifolia Bouch.' were higher than those of 'Chuandilong' at this NaHCO3 concentration. These results suggested that under greater NaHCO 3 stress, these pumpkin cultivars showed significant inhibition of growth, with 'C. ficifolia Bouch.' being more sensitive than 'Chuandilong' to NaHCO3 stress. Injury caused by NaHCO 3 stress was most likely mitigated by increasing the antioxidant activities of SOD and POD and accumulating proline and soluble sugar contents to facilitate osmotic adjustment.

An attractive way of egg white protein by-product use for producing of novel anti-hypertensive peptides

The aim of this study was to (i) examine how enzymatic hydrolysis with a non-commercially available proteinase of fig-leaf gourd fruit (Cucurbita ficifolia) increased the use value of egg white protein preparations, generated as byproducts in the industrial process of lysozyme and cystatin isolation from egg white, and (ii) evaluate the inhibition of angiotensin I-converting enzyme (ACE) by the obtained hydrolysates. Purification procedures including membrane filtration, gel filtration chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) led to the production of several peptide fractions. Two novel ovalbumin-derived tetrapeptides: SWVE (f 148–151) and DILN (f 86–89) with ACE inhibitory activity were obtained. Study of their inhibitory kinetics revealed a non-competitive binding mode, with an IC50 value against ACE of 33.88 and 73.44μg for SWVE and DILN, respectively. Synthetic peptides which were designed on the basis of peptide SWVE were examined. A tripeptide sequence of SWV revealed the strongest ACE-inhibitory activity.

Developmental Characteristics and Cinnamic Acid Resistance of Root Border Cells in Cucumber and Figleaf Gourd Seedlings

Root border cells (RBCs) originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and figleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and figleaf gourd seedlings. CA ranging from 0 to 0.25 mol L−1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more significant in the CA-sensitive cucumber than in the CA-tolerant figleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a significantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in figleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity.

Effect of grafting on anatomical and physiological characteristics on Nubian watermelon plant.

Two field experiments were carried out on Nubian watermelon (Citrullus lanatus var.Colocynthoide) during the summer season of 2009 and 2010 in the farm of Sakha ResearchStation in Kafr El-Sheikh Governorate. The main objective of the study was to compare betweenthe four rootstocks: bottle gourd (Lagenaria siceraria), pumpkin (Cucurbita moschata), luffa(Luffa cylindrical) and fig leaf gourd (Cucurbita ficifolia) with non-grafted plants. The studyincluded measurement of biochemical analysis of leaves and seeds, anatomical structure of thegrafting union and successful grafting percentage. In general, grafting plants onto bottle gourdhad higher nitrogen, phosphorus and potassium percentage, while the lowest values wereobtained from grafting plants onto fig leaf gourd. Grafting onto different rootstocks significantlydecreased oil content compared with non-grafted plants. On contrast, carbohydrate content wasincreased by grafting. Nubian watermelon grafted onto luffa had the highest protein content,while the lowest protein contents were obtained from grafting plants onto bottle gourd and fromnon-grafted plants. Grafting onto different rootstocks significantly increased area of both xylemand phloem compared with non-grafted plants. Also, grafting Nubian watermelon onto fig leafgourd and bottle gourd had the highest successful grafting percentage.

Effect of grafting Nubian watermelon on its growth, flowering, yield and fruit quality.

Two field experiments were carried out on Nubian watermelon (Citrullus lanatus var.Colocynthoide) during the summer season of 2009 and 2010 in the farm of Sakha ResearchStation in Kafr El-Sheikh Governorate. The main objective of the study was comparison of nongraftedwatermelon plants with four rootstocks: bottle gourd (Lagenaria siceraria), pumpkin(Cucurbita moschata), luffa (Luffa cylindrical) and fig leaf gourd (Cucurbita ficifolia) toimprove Nubian watermelon production by using grafting technique. The study includedmeasurement of vegetative growth parameters, flowering, fruit and seed yield and fruitcharacteristics.The results indicated that grafting Nubian watermelon onto bottle gourd and pumpkin rootstockswas the best grafting compared to the control.Grafting onto bottle gourd rootstock significantly increased number of hermaphrodite flowerwhile, the lowest numbers were obtained from non-grafted plants and those grafted onto luffa.Grafting onto bottle gourd significantly increased both number of fruit/plant, seeds/ fruit andfruit weight, while non-grafting plants and grafting onto fig leaf gourd led to lowest values ofthem. Grafting onto bottle gourd followed by pumpkin significantly increased fruit yield per m2,seed yield per m2, both weights of fruit yield (ton/fed.) and seed yield (ton/fed) in comparisonwith non-grafting plants and grafting onto luffa.Plants grafting onto bottle gourd rootstock had the highest dry weight of 100 seeds, net weightof seed kernel values, the highest fruit length, fruit diameter and fruit shape values.The main objective of this investigation was chosen suitable rootstock for grafting and studyingits effect on growth and yield of Nubian watermelon plant.

Grafting Raises the Cu Tolerance of Cucumber Through Protecting Roots Against Oxidative Stress Induced by Cu Stress

A greenhouse experiment was carried out to determine plant growth, reactive oxygen species (ROS) metabolism in roots and functions of plasma membrane (PM) and tonoplast in cucumber seedlings (Cucumis sativus L. cv. Xintaimici) treated with 40 μmol L−1 CuSO4·5H2O, which were either ungrafted or grafted onto the rootstock (Cucurbita ficifolia). Cu treatment inhibited growth, induced significant accumulation of H2O2 and led to serious lipid peroxidation in cucumber roots, and the ROS-scavenging enzymes activities in grafted seedlings roots were significantly higher than that of ungrafted plants, thus less accumulation in grafted cucumber roots induced by Cu. As a result, lipid peroxidation in roots decreased. Furthermore, the activities of H+-ATPase, H+-PPase and Ca2+-ATPase in PM and/or tonoplast in grafted cucumber seedlings under Cu stress were obviously higher than that in ungrafted plants, resulting into higher ability in grafted plants to expulse the excess H+, promote the cytoplasm alkalinization, regulate the intracellular Ca2+ concentration and brought the cytoplasma concentration of free Ca2+ to extremely low level under Cu stress.

Rootstocks improve cucumber photosynthesis through nitrogen metabolism regulation under salt stress

We examined the growth, photosynthetic parameters, initial and total ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, the relative expression of rbcL, rbcS, and rca gene, and nitrogen metabolism of cucumber (Cucumis sativus L. cv. Jinchun No.2, CS) plants grafted onto figleaf gourd (Cucurbita ficifolia Bouche, CF) and pumpkin (Cucurbita moschata Duch. cv. Chaojiquanwang, CM) rootstocks. Growth inhibition under salt stress (90 mM NaCl) was characterized by the irreversible inhibition of CO2 assimilation in the cucumber plants grafted onto cucumber rootstocks (CS/CS). In contrast, this effect was significantly alleviated by grafting the cucumber plants onto the CF and CM roots (CS/CF, CS/CM). Under NaCl stress, the CS/CF and CS/CM plants exhibited higher photosynthetic activity, higher initial and total Rubisco activity, and higher Rubisco-related gene expression than the CS/CS plants. Salinity resulted in a lesser increase in nitrate content and decrease in free amino acid content in the CS/CF and the CS/CM plants compared with the CS/CS plants. Accordingly, the activity of nitrate reductase, glutamine synthetase, and glutamate synthase decreased significantly, especially in the CS/CS plants. These results suggest that grafting cucumber plants onto salt-tolerant rootstocks enhances Rubisco activity and the expression of Rubisco-related genes by effectively accelerating nitrate transformation into amino acids under NaCl stress, thereby improving the photosynthetic performance of cucumber leaves.

Application of Asian pumpkin (Cucurbita ficifolia) serine proteinase for production of biologically active peptides from casein.

The main objective of this study was to determine potential application of a serine proteinase derived from Asian pumpkin for obtaining biologically active peptides from casein. The course of casein hydrolysis by three doses of the enzyme (50, 150, 300 U/mg of protein) was monitored for 24 hours by the determinations of: hydrolysis degree DH (%), free amino group content (μmole Gly/g), RP HPLC peptide profiles and by polyacrylamide gel electrophoresis. In all hydrolyzates analyzed antioxidant activities were determined using three tests: the ability to reduce iron ions in FRAP test, the ability to scavenge free radicals in DPPH test, and Fe(2+) chelating activity. The antimicrobial activity of obtained peptide fractions was determined as the ability to inhibit the growth of Escherichia coli, Bacillus cereus and Pseudomonas fluorescens in a diffusion plate test. The deepest degradation, expressed as the DH [%] and the free amino group content (67% and 7528 µmole Gly/mg, respectively), was noted in samples hydrolyzed with 300 U/ml of enzyme for 24 hours, while in other samples the determined values were about three and two times lower. The results were in agreement with the peptide profiles obtained by RP HPLC. The highest antioxidative activities determined in all tests were seen for the casein hydrolysate obtained with 300 U/mg protein of serine proteinase after 24 h of reaction (2.15 µM Trolox/mg, 96.15 µg Fe(3+)/mg, 814.97 µg Fe(2+)/mg). Antimicrobial activity was presented in three preparations. In other samples no antimicrobial activity was detected.

Effect of an aqueous extract of Cucurbita ficifolia Bouché on the glutathione redox cycle in mice with STZ-induced diabetes

Ethnopharmacological importanceCucurbita ficifolia is used in Mexican traditional medicine as an anti-diabetic and anti-inflammatory agent and its actions can be mediated by antioxidant mechanisms. Disturbance in the homeostasis of glutathione has been implicated in the etiology and progression of diabetes mellitus and its complications. Material and methodsIt was evaluated, the effect of an aqueous extract of Cucurbita ficifolia on glycemia, plasma lipid peroxidation; as well as levels of reduced (GSH) and oxidized (GSSG) glutathione and activities of enzymes involved in glutathione redox cycle: glutathione peroxidase (GPx) and glutathione reductase (GR) in liver, pancreas, kidney and heart homogenates of streptozotocin-induced diabetic mice. ResultsIncreased blood glucose and lipid peroxidation, together with decreased of GSH concentration, GSH/GSSG ratio and its redox potential (Eh), and enhanced activity of GPx and GR in liver, pancreas and kidney were the salient features observed in diabetic mice. Administration of the aqueous extract of Cucurbita ficifolia to diabetic mice for 30 days, used at a dose of 200mg/kg, resulted in a significant reduction in glycemia, polydipsia, hyperphagia and plasma lipid peroxidation. Moreover, GSH was increased in liver, pancreas and kidney, and GSSG was reduced in liver, pancreas and heart, therefore GSH/GSSG ratio and its Eh were restored. Also, the activities involved in the glutathione cycle were decreased, reaching similar values to controls. ConclusionsAn aqueous extract of Cucurbita ficifolia with hypoglycemic action, improve GSH redox state, increasing glutathione pool, GSH, GSH/GSSG ratio and its Eh, mechanism that can explain, at least in part, its antioxidant properties, supporting its use as an alternative treatment for the control of diabetes mellitus, and prevent the induction of complications by oxidative stress.

Optimization of substrate formulation and mineral nutrition during the production of vegetable seedling grafts

The use of seedling grafts has been increasingly popular in the production of fruit vegetables in Korea. Superior scion cultivars grafted on seedling rootstocks tolerant to soil-borne diseases often results in higher crop yield and quality. For the production of healthy grafted transplants, seedlings have to be grown under the most favorable cultural conditions. Substrate composition and property as well as mineral nutrition play an important role. Various substrates containing peatmoss, perlite, vermiculite, and coir-dust have been tested for their influence on seedling growth. In the chemical properties of substrates investigated just before grafting and after formation of grafted union, the ECs in 4 substrates rose as the pre-plant fertilizer level was elevated. The ECs in peatmoss containing substrates were lower than those in coir dust containing substrates when all substrates contained equal amount of pre-plant fertilizers. The ECs in substrates containing vermiculite were higher than those in perlite. In all substrates, the elevation of pre-plant fertilizer levels resulted in the increase in NO3−-N and K+ concentrations and decrease in Na+ concentration. The recommended EC levels of substrates for the raising of plug seedlings of bedding plants are applicable to fruit vegetables when the seedlings are grown in peatmoss + perlite (PP) substrate. But those in peatmoss + vermiculite (PV), coir-dust + perlite (CP) and coir-dust + vermiculite (CV) substrates should be altered based on the kinds and rates of substrate components. In case of crops, the water melon rootstock ‘Cham Bak’ (Lagenaria siceraria Standl), showed the stronger salt tolerance than cucumber rootstock ‘Heukjong Hobak’ (Cucurbita ficifolia) indicating that pre-or post-plant fertilizer levels should be varied based on the kinds of crops grown. The peppers grew well in PP and PV substrates rather than CP or CV substrates in before or after grafting. This also implies that the components of substrates should be changed based on the specific crops.

Antioxidant and Anti-Inflammatory Effects of a Hypoglycemic Fraction fromCucurbita ficifoliaBouché in Streptozotocin-Induced Diabetes Mice

Type 2 diabetes is characterized by oxidative stress and a chronic low-grade inflammatory state, which also play roles in the pathogenesis of this disease and the accompanying vascular complications by increasing the production of free radicals and pro-inflammatory cytokines. Cucurbita ficifolia Bouché (C. ficifolia) is an edible Mexican plant whose hypoglycemic activity has been demonstrated in several experimental and clinical conditions. Recently, D-chiro-inositol has been proposed as the compound responsible for the hypoglycemic effects; however, the antioxidant and anti-inflammatory potential of this plant has not yet been explored. The aim of this research is to study the influence of a hypoglycemic, D-chiro-inositol-containing fraction from the C. ficifolia fruit (AP-Fraction) on biomarkers of oxidative stress, as well as on the inflammatory cytokines in streptozotocin-induced diabetes. The AP-Fraction obtained from the mature fruit of C. ficifolia contained 3.31 mg of D-chiro-inositol/g of AP-Fraction. The AP-Fraction was administrated daily by gavage to normal mice for 15 days as a preventive treatment. Then these animals were given streptozotocin, and the treatments were continued for an additional 33 days. Pioglitazone was used as a hypoglycemic drug for comparison. Administration of the AP-Fraction significantly increased glutathione (GSH) and decreased malondialdehyde (MDA) in the liver without significantly affecting the levels in other tissues. The AP-Fraction reduced TNF-α and increased IL-6 and IFN-γ in serum. Interestingly, the AP-Fraction also increased IL-10, an anti-inflammatory cytokine. These results suggest that C. ficifolia might be used as an alternative medication for the control of diabetes mellitus and that it has antioxidant and anti-inflammatory properties in addition to its hypoglycemic activity.

Effect of nutrient deficiencies on the water transport properties in figleaf gourd plants

Effects of nitrogen, phosphorus, and potassium deficiencies on water transport properties in figleaf gourd plants were studied. Plants were treated for different period of deficiency and physiological parameters such as stomatal conductance, photosynthesis and transpiration were measured. Cell and root pressure probes were utilized to measure turgor and root pressures, half-times of water exchange and hydraulic conductivities to analyze water transport properties. When plants were grown in nitrogen or phosphorus deficient nutrient solutions, they became insensitive to mercury, suggesting that aquaporin was closed resulting in reduced hydraulic conductivity. Inclusion of tungstate, however, restored the sensitivity of cells to mercury, indicating the importance of internal nutrient concentration, not the incoming nutrient supply. The hydrostatic hydraulic conductivity of roots grown in nitrogen deficient solution, representing apoplastic pathway of water transport, was reduced but this reduction was dramatically recovered by the application of tungstate, indicating the importance of nutrient availability from storage pools in relation to water status of plants.

Temperature effects on the reactive oxygen species formation and antioxidant defence in roots of two cucurbit species with contrasting root zone temperature optima

Suboptimal root zone temperature (14°C) was imposed on chilling-sensitive cucumber (Cucumis sativus L.) and chilling-tolerant figleaf gourd (Cucurbita ficifolia Bouche) plants. Exposure of roots to low temperature for up to 10 days caused a strong growth inhibition in cucumber compared with figleaf gourd. Physiological analysis showed that generation of reactive oxygen species (ROS) such as hydrogen peroxide and superoxide anion was significantly induced in cucumber plants as fast as 1 day after low root zone temperature treatment. In addition to the significant induction of antioxidant superoxide dismutase activity, low root zone temperature also increased the mitochondrial electron transport allocated to alternative pathway while decreased cytochrome pathway salicylhydroxamic acid-resistant respiration. However, these defense responses could not compensate for the ROS production, resulting in membrane lipid peroxidation and loss of root cell viability in the low root zone temperature treated cucumber roots. In contrast, 14°C root zone temperature had no significant effects on figleaf gourd plant growth, antioxidant enzymes, ROS levels and alternative respiratory pathway. Hence, difference in ROS metabolism would be associated with the remarkable difference in adaptability of cucumber and figleaf gourd plants in response to suboptimal root zone temperature condition.