| influence of cultivar, cooking, and storage on cell-wall polysaccharide composition of winter squash (cucurbita maxima). | changes in the cell-wall polysaccharides (cwp) of the edible tissues of four winter squash cultivars during storage and after cooking were investigated. a procedure for isolating cell walls of tissues containing high levels of starch was used. the starch-free cwp were sequentially fractionated using cdta, dilute na(2)co(3), and 4 m koh. cellulose made up 40-42% of the total cwp for three cultivars (delica, cf 2, and cf 4) at harvest but was 35% in the softer red warren. the pectic polysaccharide ... | 2003 | 12643650 |
| metabolic networks of cucurbita maxima phloem. | metabolomic analysis aims at a comprehensive characterization of biological samples. yet, biologically meaningful interpretations are often limited by the poor spatial and temporal resolution of the acquired data sets. one way to remedy this is to limit the complexity of the cell types being studied. cucurbita maxima duch. vascular exudates provide an excellent material for metabolomics in this regard. using automated mass spectral deconvolution, over 400 components have been detected in these e ... | 2003 | 12590115 |
| correlation of binding-loop internal dynamics with stability and function in potato i inhibitor family: relative contributions of arg(50) and arg(52) in cucurbita maxima trypsin inhibitor-v as studied by site-directed mutagenesis and nmr spectroscopy. | the side chains of arg(50) and arg(52) at positions p(6)' and p(8)', respectively, anchor the binding loop to the protein scaffold by means of hydrogen bonds in cucurbita maxima trypsin inhibitor-v (cmti-v), a potato i family member. here, we have investigated the relative contributions of arg(50) and arg(52) to the binding-loop flexibility and stability by determining changes in structure, dynamics, and proteolytic stability as a consequence of individually mutating them into an alanine. we hav ... | 2002 | 12135379 |
| exact and effective pair-wise potential for protein-ligand interactions obtained from a semiempirical energy partition. | in this work, the partition method introduced by carvalho and melo was used to study the complex between cucurbita maxima trypsin inhibitor (cmti-i) and glycerol at the am1 level. an effective potential, combining non-bonding and polarization plus charge transfer (plct) terms, was introduced to evaluate the magnitude of the interaction between each amino acid and the ligand. in this case study, the nonbonding-plct non-compensation characterizes the stabilization energy of the association process ... | 2008 | 19325823 |
| the phloem-delivered rna pool contains small noncoding rnas and interferes with translation. | in plants, the vascular tissue contains the enucleated sieve tubes facilitating long-distance transport of nutrients, hormones, and proteins. in addition, several mrnas and small interfering rnas/micrornas were shown to be delivered via sieve tubes whose content is embodied by the phloem sap (ps). a number of these phloem transcripts are transported from source to sink tissues and function at targeted tissues. to gain additional insights into phloem-delivered rnas and their potential role in sig ... | 2009 | 19261735 |
| a polypyrimidine tract binding protein, pumpkin rbp50, forms the basis of a phloem-mobile ribonucleoprotein complex. | rna binding proteins (rbps) are integral components of ribonucleoprotein (rnp) complexes and play a central role in rna processing. in plants, some rbps function in a non-cell-autonomous manner. the angiosperm phloem translocation stream contains a unique population of rbps, but little is known regarding the nature of the proteins and mrna species that constitute phloem-mobile rnp complexes. here, we identified and characterized a 50-kd pumpkin (cucurbita maxima cv big max) phloem rna binding pr ... | 2009 | 19122103 |
| electronic structure of trypsin inhibitor from squash seeds in aqueous solution. | the electronic structure of the trypsin inhibitor from seeds of the squash cucurbita maxima (cmti-i) in aqueous solution is obtained by ab initio, all-electron, full-potential calculations using the self-consistent cluster-embedding (scce) method. the reactive site of the inhibitor is explained theoretically, which is in agreement with the experimental results. it is shown that the coordinates of oxygen atoms in the inhibitor, determined by nuclear magnetic resonance and combination of distance ... | 2000 | 11089109 |
| phloem-specific expression of the pumpkin fruit trypsin inhibitor. | vascular exudates of cucurbita maxima (duch.) contain a group of highly conserved serine proteinase inhibitors collectively called pumpkin fruit trypsin inhibitors (pftis) that prevent proteolytic activity of trypsin or chymotrypsin. polyclonal antibodies raised against pftis were used to immunolocalize these low-molecular-weight proteins within the phloem tissue and to study their developmental expression. the inhibitors were translocated throughout the transport phloem and were present in vasc ... | 2001 | 11216835 |
| ecology of nematodes under influence of cucurbita spp. and different fertilizer types. | in a field study conducted in georgia, cucurbit plants with high (cucurbita andreana) and low (cucurbita maxima) concentrations of cucurbitacins were used in combination with two types of fertilizers to investigate their effects on the community of soil nematodes. ecological measures of soil nematode community structure such as total nematode abundance, number of genera, trophic diversity, trophic group proportions, fungivore/bacterivore ratio, and modified maturity index were assessed and compa ... | 1995 | 19277330 |
| characterization of cucurbita maxima phloem serpin-1 (cmps-1). a developmentally regulated elastase inhibitor. | we report on the molecular, biochemical, and functional characterization of cucurbita maxima phloem serpin-1 (cmps-1), a novel 42-kda serine proteinase inhibitor that is developmentally regulated and has anti-elastase properties. cmps-1 was purified to near homogeneity from c. maxima (pumpkin) phloem exudate and, based on microsequence analysis, the cdna encoding cmps-1 was cloned. the association rate constant (k(a)) of phloem-purified and recombinant his(6)-tagged cmps-1 for elastase was 3.5 + ... | 2000 | 10960478 |
| qualitative and quantitative differences in carotenoid composition among cucurbita moschata, cucurbita maxima, and cucurbita pepo. | squashes and pumpkins are important dietary sources of carotenoids worldwide. the carotenoid composition has been determined, but reported data have been highly variable, both qualitatively and quantitatively. in the present work, the carotenoid composition of squashes and pumpkins currently marketed in campinas, brazil, were determined by hplc-dad, complemented by hplc-ms for identification. cucurbita moschata 'menina brasileira' and c. moschata 'goianinha' had similar profiles, with beta-carot ... | 2007 | 17444652 |
| differences in p,p'-dde bioaccumulation from compost and soil by the plants cucurbita pepo and cucurbita maxima and the earthworms eisenia fetida and lumbricus terrestris. | two plant species, cucurbita pepo and cucurbita maxima, and two earthworm species, eisenia fetida and lumbricus terrestris, were exposed to soil and compost with equivalent p,p'-dde contamination. pollutant bioconcentration was equal in plant roots in both media, but translocation was higher in c. pepo. bioaccumulation by e. fetida was approximately 6- and 3-fold higher than that by l. terrestris in the soil and compost, respectively. for all species, p,p'-dde uptake was significantly greater fr ... | 2007 | 17241722 |
| wound-induced ethylene synthesis and expression and formation of 1-aminocyclopropane-1-carboxylate (acc) synthase, acc oxidase, phenylalanine ammonia-lyase, and peroxidase in wounded mesocarp tissue of cucurbita maxima. | 1-aminocyclopropane-1-carboxylate (acc) synthase was rapidly induced in mesocarp tissue of cucurbita maxima after wounding in the cut surface layer in 1 mm thickness (ca. 9 cells) (first layer) in both the enzyme activity and the levels of transcript. this led to a rapid accumulation of acc and hence ethylene production. in the inside tissue (1-2 mm) (second layer), no significant induction of acc synthase was observed, which resulted in a low level of acc, although ethylene was evolved at a muc ... | 2000 | 10845457 |
| factors improving the accuracy of determination of 15n relaxation parameters in proteins. | a number of factors at all stages of data processing which affect the accuracy of determination of 15n relaxation parameters in 15n-labeled proteins is discussed. methods which allow to improve accuracy of the determined parameters are presented using data obtained for cucurbita maxima trypsin inhibitor. | 1999 | 10698274 |
| gibberellin biosynthesis in developing pumpkin seedlings. | a gibberellin (ga) biosynthetic pathway was discovered operating in root tips of 7-d-old pumpkin (cucurbita maxima) seedlings. stepwise analysis of ga metabolism in cell-free systems revealed the conversion of ga(12)-aldehyde to bioactive ga(4) and inactive ga(34). highest levels of endogenous ga(4) and ga(34) were found in hypocotyls and root tips of 3-d-old seedlings. cdna molecules encoding two ga oxidases, cmga20ox3 and cmga3ox3, were isolated from root tips of 7-d-old lab150978-treated seed ... | 2005 | 16126862 |
| single peptide bond hydrolysis/resynthesis in squash inhibitors of serine proteinases. 2. limited proteolysis of curcurbita maxima trypsin inhibitor i by pepsin. | porcine pepsin hydrolyzes the leu7-met8 (p2'-p3') peptide bond in cucurbita maxima trypsin inhibitor i (cmti i) in the ph range 2.0-4.8. the reaction proceeds to equilibrium between intact cmti i and its cleaved form. the ph-independent value of the equilibrium constant (khyd0 = 0.78) indicates that both forms of the inhibitor have similar gibbs energies. the ph dependence of this constant shows that the peptide bond hydrolysis does not perturb ionization constants of any preexistent groups. the ... | 1994 | 8286342 |
| phenolic profiles of raw apricots, pumpkins, and their purees in the evaluation of apricot nectar and jam authenticity. | the possibility of proving the undeclared addition of pumpkin puree in apricot nectars and jams has been investigated by using the phenol compound fingerprint and sensory evaluation. the cheaper pumpkin admixtures in apricot nectars and jams could not be detected by the sensory evaluation, particularly if present in quantities of <15%. the lower admixtures of pumpkin puree in apricot nectars and jams could be detected by the presence of syringic acid, a phenolic compound characteristic of the in ... | 2005 | 15941324 |
| multi-species interactions impact the accumulation of weathered 2,2-bis (p-chlorophenyl)-1,1-dichloroethylene (p,p'-dde) from soil. | the impact of interactions between the earthworms eisenia foetida and lumbricus terrestris and the plants cucurbita pepo and cucurbita maxima on the uptake of weathered p,p'-dde from soil was determined. although some combinations of earthworm and plant species caused significant changes in the p,p'-dde burden in both organisms, the effects were species specific. contaminant bioconcentration in c. pepo was increased slightly by e. foetida and by 3-fold when the plant was grown with l. terrestris ... | 2005 | 15913856 |
| phloem long-distance transport of cmnacp mrna: implications for supracellular regulation in plants. | direct support for the concept that rna molecules circulate throughout the plant, via the phloem, is provided through the characterisation of mrna from phloem sap of mature pumpkin (cucurbita maxima) leaves and stems. one of these mrnas, cmnacp, is a member of the nac domain gene family, some of whose members have been shown to be involved in apical meristem development. in situ rt-pcr analysis revealed the presence of cmnacp rna in the companion cell-sieve element complex of leaf, stem and root ... | 1999 | 10498677 |
| analysis of phloem protein patterns from different organs of cucurbita maxima duch. by matrix-assisted laser desorption/ionization time of flight mass spectroscopy combined with sodium dodecyl sulfate polyacrylamide gel electrophoresis. | sieve tubes mediate the long-distance transport of nutrients and signals between source and sink organs of plants. to detect mobile phloem proteins that are differentially distributed in source and sink organs of cucurbita maxima, we used both one-dimensional gel electrophoresis (sds-page) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof ms). both techniques revealed that phloem protein patterns depend on the sampling site: whilst several proteins were ... | 1999 | 10093900 |
| matrix-assisted laser desorption/ionization time of flight mass spectrometry peptide mass fingerprints and post source decay: a tool for the identification and analysis of phloem proteins from cucurbita maxima duch. separated by two-dimensional polyacrylamide gel electrophoresis. | a combination of gel electrophoresis and mass spectrometry was used to analyze the soluble proteins from phloem sap of cucurbita maxima duch. phloem proteins were separated using two-dimensional gel electrophoresis. coomassie-stained spots were cut out and subjected to tryptic digestion. to identify proteins, peptide mass fingerprints were determined by matrix-assisted laser desorption/ionization time of flight (maldi-tof) mass spectrometry. in addition, maldi-tof post source decay measurements ... | 2001 | 11556791 |
| disulfide bond effects on protein stability: designed variants of cucurbita maxima trypsin inhibitor-v. | attempts to increase protein stability by insertion of novel disulfide bonds have not always been successful. according to the two current models, cross-links enhance stability mainly through denatured state effects. we have investigated the effects of removal and addition of disulfide cross-links, protein flexibility in the vicinity of a cross-link, and disulfide loop size on the stability of cucurbita maxima trypsin inhibitor-v (cmti-v; 7 kd) by differential scanning calorimetry. cmti-v offers ... | 2001 | 11266603 |
| plant paralog to viral movement protein that potentiates transport of mrna into the phloem. | cmpp16 from cucurbita maxima was cloned and the protein was shown to possess properties similar to those of viral movement proteins. cmpp16 messenger rna (mrna) is present in phloem tissue, whereas protein appears confined to sieve elements (se). microinjection and grafting studies revealed that cmpp16 moves from cell to cell, mediates the transport of sense and antisense rna, and moves together with its mrna into the se of scion tissue. cmpp16 possesses the characteristics that are likely requi ... | 1999 | 9872750 |
| the first step of gibberellin biosynthesis in pumpkin is catalyzed by at least two copalyl diphosphate synthases encoded by differentially regulated genes. | the first step in gibberellin biosynthesis is catalyzed by copalyl diphosphate synthase (cps) and ent-kaurene synthase. we have cloned from pumpkin (cucurbita maxima l.) two cdnas, cmcps1 and cmcps2, that each encode a cps. both recombinant fusion cmcps proteins were active in vitro. cps are translocated into plastids and processed by cleavage of transit peptides. for cmcps1 and cmcps2, the putative transit peptides cannot exceed the first 99 and 107 amino acids, respectively, because longer n-t ... | 1998 | 9847116 |
| nmr studies of internal dynamics of serine proteinase protein inhibitors: binding region mobilities of intact and reactive-site hydrolyzed cucurbita maxima trypsin inhibitor (cmti)-iii of the squash family and comparison with those of counterparts of cmti-v of the potato i family. | serine proteinase protein inhibitors follow the standard mechanism of inhibition (laskowski m jr, kato i, 1980, annu rev biochem 49:593-626), whereby an enzyme-catalyzed equilibrium between intact (i) and reactive-site hydrolyzed inhibitor (i*) is reached. the hydrolysis constant, khyd, is defined as [i*]/[i]. here, we explore the role of internal dynamics in the resynthesis of the scissile bond by comparing the internal mobility data of intact and cleaved inhibitors belonging to two different f ... | 1998 | 9514268 |
| phloem sap proteins from cucurbita maxima and ricinus communis have the capacity to traffic cell to cell through plasmodesmata. | in angiosperms, the functional enucleate sieve tube system of the phloem appears to be maintained by the surrounding companion cells. in this study, we tested the hypothesis that polypeptides present within the phloem sap traffic cell to cell from the companion cells, where they are synthesized, into the sieve tube via plasmodesmata. coinjection of fluorescently labeled dextrans along with size-fractionated cucurbita maxima phloem proteins, ranging in size from 10 to 200 kda, as well as injectio ... | 1997 | 9391168 |
| molecular characterization of a phloem-specific gene encoding the filament protein, phloem protein 1 (pp1), from cucurbita maxima. | sieve elements in the phloem of most angiosperms contain proteinaceous filaments and aggregates called p-protein. in the genus cucurbita, these filaments are composed of two major proteins: pp1, the phloem filament protein, and pp2, the phloem lactin. the gene encoding the phloem filament protein in pumpkin (cucurbita maxima duch.) has been isolated and characterized. nucleotide sequence analysis of the reconstructed gene gpp1 revealed a continuous 2430 bp protein coding sequence, with no intron ... | 1997 | 9263452 |
| differential modulation of binding loop flexibility and stability by arg50 and arg52 in cucurbita maxima trypsin inhibitor-v deduced by trypsin-catalyzed hydrolysis and nmr spectroscopy. | the side chains of arg50 and arg52 iin cucurbita maxima trypsin inhibitor-v (cmti-v) anchor the binding loop to the scaffold region [cai, m., gong, y., kao, j.l-f., & krishnamoorthi, r. (1995) biochemistry 34, 5201-5211]. the consequences of these hydrogen-bonding and electrostatic interactions on the conformational flexibility and stability of the binding loop were evaluated by trypsin-catalyzed hydrolysis of cmti-v mutants, in which each of the arginines was individually replaced with ala, lys ... | 1996 | 8664268 |
| analysis of the complexity of protein kinases within the phloem sieve tube system. characterization of cucurbita maxima calmodulin-like domain protein kinase 1. | in angiosperms, functional, mature sieve elements lack nuclei, vacuoles, ribosomes, and most of the endomembrane network. in this study, the complexity, number, and nature of protein kinases within the phloem sap of cucurbita maxima were investigated to test the hypothesis that the enucleate sieve tube system utilizes a simplified signal transduction network. supporting evidence was obtained in that only five putative protein kinases (three calcium-independent and two calcium-dependent protein k ... | 2002 | 11847230 |
| [color loss evaluation of a dietary formulation in function of temperature, storage time and packaging]. | color loss of a dietetic formulae based on pumpkin (cucurbita maxima), rice, hen and vegetable oils was evaluated. the product was under an accelerated test at temperatures of 40, 50 and 70 degrees c for a month. the kinetic reaction of color loss (quality loss indicator) was obtained with n = 1 and ea = 11.5 kcal/mol. the product was also stored for sixth months at temperatures of 25, 30, 35 and 40 degrees c using glass containers, laminated and composite cans (non metallic). the color was meas ... | 1996 | 9161461 |
| solution structure and backbone dynamics of recombinant cucurbita maxima trypsin inhibitor-v determined by nmr spectroscopy. | the solution structure of recombinant cucurbita maxima trypsin inhibitor-v (rcmti-v), whose n-terminal is unacetylated and carries an extra glycine residue, was determined by means of two-dimensional (2d) homo and 3d hetero nmr experiments in combination with a distance geometry and simulated annealing algorithm. a total of 927 interproton distances and 123 torsion angle constraints were utilized to generate 18 structures. the root mean squared deviation (rmsd) of the mean structure is 0.53 a fo ... | 1996 | 8634282 |
| heterogeneity and organization of the ribosomal rna genes of cucurbita maxima. | thirty-six clones were recovered from cucurbita maxima genomic dna which had been enriched for rdna and cleaved at the unique repeat unit hind iii site. twenty-nine of these, which contain complete rdna units, were compared to a standard whose intergenic spacer (igs) nucleotide sequence has been determined. twenty-one are identical in length and restriction site pattern. eight which differ from the standard in length do so because of addition or deletion of varying numbers of igs subrepetitive u ... | 1990 | 2102876 |
| the development of phloem anastomoses between vascular bundles and their role in xylem regeneration after wounding in cucurbita and dahlia. | the differentiation of phloem anastomoses linking the longitudinal vascular bundles has been studied in stem internodes of cucurbita maxima duchesne, c. pepo l. and dahlia pinnata cav. these anastomoses comprise naturally occurring regenerative sieve tubes which redifferentiate from interfascicular parenchyma cells in the young internodes. in all three species, severing a vascular bundle in a young internode resulted in regeneration of xylem to form a curved by-pass immediately around the wound. ... | 1996 | 28321670 |
| improved purification and spectroscopic properties of squash glutamate decarboxylase. | squash glutamate decarboxylase was purified by deae-cellulose batchwise followed by blue-sepharose, cellulofine gcl-2000, and toyopearl hw-55f column chromatography. the purified glutamate decarboxylase had a high specific activity (95.0 u/mg). the absorption spectrum of glutamate decarboxylase had an absorption maximum at 420 nm in the range 300-500 nm. a ph change from 5.3 to 7.8 was accompanied by a decrease in absorbancy at 420 nm. one mole of glutamate decarboxylase contained 3.8 and 1.3 mo ... | 1996 | 27281150 |
| analysis of highly polar compounds of plant origin: combination of hydrophilic interaction chromatography and electrospray ion trap mass spectrometry. | the primary goal of metabolomic analysis is the unbiased relative quantification of every metabolite in a biological system. a number of different metabolite-profiling techniques must be combined to make this possible. here we report the separation and analysis of highly polar compounds in a proof of concept study. compounds were separated and analyzed using hydrophilic interaction liquid chromatography (hilic) coupled to electrospray ionization (esi) mass spectrometry. two types of hilic microb ... | 2002 | 11814300 |
| purification of a trypsin inhibitor (pfti) from pumpkin fruit phloem exudate and isolation of putative trypsin and chymotrypsin inhibitor cdna clones. | the major trypsin inhibitor from pumpkin (cucurbita maxima cv supermarket hybrid) fruit phloem exudate was purified by affinity and reverse phase chromatography. the protein has a molecular weight of approximately 8100 by sds-page and is blocked at the n-terminal serine. following sequencing of a cnbr fragment, 3'- and 5'-race were used to isolate full length cdnas corresponding to a trypsin inhibitor and to two chymotrypsin inhibitors. the three genes are similar, both in their translated and n ... | 1995 | 7662170 |
| three-dimensional solution structure of cucurbita maxima trypsin inhibitor-v determined by nmr spectroscopy. | the solution structure of cucurbita maxima trypsin inhibitor-v (cmti-v), which is also a specific inhibitor of the blood coagulation protein, factor xiia, was determined by 1h nmr spectroscopy in combination with a distance-geometry and simulated annealing algorithm. sequence-specific resonance assignments were made for all the main-chain and most of the side-chain hydrogens. stereospecific assignments were also made for some of the beta-, gamma-, delta-, and epsilon-hydrogens and valine methyl ... | 1995 | 7711040 |
| growth of cucurbita maxima l. plants in the presence of the cycloartenol synthase inhibitor u18666a. | squash, like other cucurbitaceae, have unique sterol profiles that offer an excellent opportunity to examine the relationship between sterol biosynthesis and plant growth. to determine the effect of sterol biosynthesis inhibition on squash growth, cucurbita maxima seedlings with and without cotyledons were subjected to increasing concentrations of the cycloarternol synthase (ec 5.4.99.8) inhibitor 3 beta-(2-diethylaminoethoxy)androstenone (u18666a). inhibition of shoot growth was concentration-d ... | 1995 | 7791534 |
| aluminum-induced rapid root inhibition and changes in cell-wall components of squash seedlings. | growth of squash (cucurbita maxima duch.) roots was significantly inhibited by 1 mm alcl3 as early as 1 h after the treatment. the growth inhibition was confined to the elongating zone (1-6 mm from the root tip). chemical analysis of cell-wall polysaccharides from roots revealed that aluminum increased pectin, hemi-cellulose, and cellulose contents after 3 h of treatment. the effect of aluminum on pectin content was found in the elongating zone including the root tip, whereas change in cellulose ... | 1994 | 12232377 |
| organization and characterization of cucurbita phloem lectin genes. | the phloem of pumpkin and squash contains a dimeric chitin-binding lectin called pp2 (phloem protein 2). we have isolated three genomic clones from pumpkin (cucurbita maxima duch.) that encoded pp2. one clone, lambda gpc13-1, contained two pp2 genes that were 99.8% identical over a region of 3055 nucleotides. this conserved region included 1922 bp of 5' non-coding sequence, 844 bp of protein coding sequence (including two introns), and 289 bp of 3' non-coding sequence. to examine the conservatio ... | 1994 | 8000002 |
| immunocytochemical localisation of phloem lectin from cucurbita maxima using peroxidase and colloidal-gold labels. | antibodies were raised against lectin purified from the sieve-tube exudate of cucurbita maxima. immunocytochemistry, using peroxidase-labelled antibodies and protein a-colloidal gold, was employed to determine the location of the lectin within the tissues and cells of c. maxima and other cucurbit species. the anti-lectin antibodies bound to p-protein aggregates in sieve elements and companion cells, predominantly in the extrafascicular phloem of c. maxima. this may reflect the low rate of transl ... | 1987 | 24233009 |
| transcription and translation of phloem protein (pp2) during phloem differentiation in cucurbita maxima. | the synthesis of a major phloem protein, pp2, was investigated by measurement of the mrna at various stages of phloem development in cucurbita. quantitative assays with immuno-electrophoresis showed that the amounts of pp2 in hypocotyls of cucurbita seedlings increased with the age of seedlings. an increase in mrna for pp2 during the early stages of seedling growth was also observed by immunoprecipitation of the invitro translation products of hypocotyl polyadenylated rna. there was close timing ... | 1987 | 24232970 |
| characterization and sequencing of cdna clone encoding the phloem protein pp2 of cucurbita pepo. | direct n-terminal amino acid sequencing of the phloem protein 2 (pp2) from 3-month old cucurbita pepo l. (pumpkin), purified by sds-page and blotted onto pvdf membrane, showed that the protein had a blocked n-terminus. however, after in situ cleavage of the polypeptide in a gel slice by cyanogen bromide, 75 residues of sequences on two cyanogen bromide fragments were determined. an oligonucleotide probe based on this amino acid sequence was used to screen a cdna library, constructed from mrna of ... | 1994 | 8111014 |
| purification and partial amino-acid sequence of gibberellin 20-oxidase from cucurbita maxima l. endosperm. | gibberellin (ga) 20-oxidase was purified to apparent homogeneity from cucurbita maxima endosperm by fractionated ammonium-sulphate precipitation, gel-filtration chromatography and anion-exchange and hydrophobic-interaction high-performance liquid chromatography (hplc). average purification after the last step was 55-fold with 3.9% of the activity recovered. the purest single fraction was enriched 101-fold with 0.2% overall recovery. apparent relative molecular mass of the enzyme was 45 kda, as d ... | 1994 | 7765793 |
| allozyme segregation ratios in the interspecific cross cucurbita maximaxc. ecuadorensis suggest that hybrid breakdown is not caused by minor alterations in chromosome structure. | the parentals of the interspecific cross cucurbita maxima xc. ecuadorensis had different isozyme phenotypes for 12 enzyme systems. characterization of the systems demonstrated that the expression and intracellular distribution of the isozymes were similar to those in other plant taxa; however, a considerable number of duplicate loci were identified, indicative of a polyploid ancestry for cucurbita. genetic analysis provided evidence for 20 loci segregating in f(2) and backcross populations. five ... | 1986 | 17246350 |
| glycine-rich analogues of cucurbita maxima trypsin inhibitor (cmti-iii) substituted by valine in position 27 display relatively low antitrypsin activity. | five new analogues of the trypsin inhibitor cmti-iii were synthesized by the solid-phase method. all analogues containing a valine residue in position 27 and glycine residues in some or all of the positions 9, 11, 14, 17, 19, 29 as well as in two cases a norleucine residue in position 8 displayed association equilibrium constants by 6-7 orders of magnitude lower than the native cmti-iii inhibitor. | 1993 | 8267878 |
| gibberellin biosynthesis in cell-free extracts from developing cucurbita maxima embryos and the identification of new endogenous gibberellins. | gibberellin (ga) biosynthetic pathways from ga12-aldehyde, ga12 and ga53 were investigated in cell-free systems from developing embryos of cucurbita maxima l. gibberellin a12-aldehyde and ga12 were converted to ga25, putative 12α-hydroxyga25, ga13 and ga39 as main products. minor products were ga4, ga34 and, when ga12 was the substrate, putative 12α-hydroxyga12. the intermediates ga15 and ga24 accumulated at low protein concentrations. the influence of various factors on ga12 metabolism was exam ... | 1993 | 24178491 |
| quaternary structure and composition of squash nadh:nitrate reductase. | nadh:nitrate reductase (ec 1.6.6.1) was isolated from squash cotyledons (cucurbita maxima l.) by a combination of blue sepharose and zinc-chelate affinity chromatographies followed by gel filtration on bio-gel a-1.5m. these preparations gave a single protein staining band (mr = 115,000) on sodium dodecyl sulfate gel electrophoresis, indicating that the enzyme is homogeneous. the native mr of nitrate reductase was found to be 230,000, with a minor form of mr = 420,000 also occurring. these result ... | 1985 | 4038708 |
| biosynthesis of 12α-and 13-hydroxylated gibberellins in a cell-free system from cucurbita maxima endosperm and the identification of new endogenous gibberellins. | gibberellin (ga) biosynthesis in cell-free systems from cucurbita maxima l. endosperm was reinvestigated using incubation conditions different from those employed in previous work. the metabolism of ga12 yielded ga13, ga43 and 12α-hydroxyga43 as major products, ga4, ga37, ga39, ga46 and four unidentified compounds as minor products. the intermediates ga15, ga24 and ga25 accumulated at low protein concentrations. the structure of the previously uncharacterised 12α-hydroxyga43 was inferred from it ... | 1993 | 24178490 |
| homonuclear three-dimensional noe-noe nuclear magnetic resonance/spectra for structure determination of proteins in solution. | the solution structures of two proteins (cmti-i, a trypsin inhibitor from cucurbita maxima, and hisactophilin, an actin binding protein of 118 amino acids) have been determined based on the noe data derived solely from the homonuclear 3d noe-noe magnetic resonance spectroscopy. two different approaches for extraction of the structural information from the 3d noe-noe experiment were tested. one approach was based on the transformation of the 3d intensities into distance constraints. in the second ... | 1992 | 1447779 |
| biosynthesis of sterols and triterpenoids in tissue cultures of cucurbita maxima. | the biosynthesis of sterols and triterpenoids in cucurbita maxima was studied by analysis of unsaponifiable fraction of tissues from different development stages of the plant (seeds, seedlings, adult plant and tissue culture) and by feeding germinating seeds and tissue cultures with [2- (14)c]-acetate. synthesis of cucurbitacins does not occur in callus tissues of cucurbita maxima, whereas a wide variety of 4,4-dimethylsterols present in these tissues testifies of a high level of squaleneoxide c ... | 1983 | 17405044 |
| natural abundance 15n nmr assignments delineate structural differences between intact and reactive-site hydrolyzed cucurbita maxima trypsin inhibitor iii. | 15n nmr assignments were made to the backbone amide nitrogen atoms at natural isotopic abundance of intact and reactive-site (arg5-ile6) hydrolyzed cucurbita maxima trypsin inhibitor iii (cmti-iii and cmti-iii*, respectively) by means of 2d proton-detected heteronuclear single bond chemical shift correlation (hsbc) spectroscopy, utilizing the previously made sequence-specific 1h nmr assignments (krishnamoorthi et al. (1992) biochemistry 31, 898-904). comparison of the 15n chemical shifts of the ... | 1992 | 1618315 |
| structural consequences of the natural substitution, e9k, on reactive-site-hydrolyzed squash (cucurbita maxima) trypsin inhibitor (cmti), as studied by two-dimensional nmr. | sequence-specific hydrogen-1 nmr assignments were made to all of the 29 amino acid residues of reactive-site-hydrolyzed cucurbita maxima trypsin inhibitor i (cmti-i*) by the application of two-dimensional nmr (2d nmr) techniques, and its secondary structural elements (two tight turns, a 3(10)-helix, and a triple-stranded beta-sheet) were identified on the basis of short-range noesy cross peaks and deuterium-exchange kinetics. these secondary structural elements are present in the intact inhibito ... | 1992 | 1599921 |
| preparation and characteristics of trypsin inhibitors from the seeds of squash (cucurbita maxima) and zucchini (cucurbita pepo var. giromontia). | one trypsin inhibitor (i) from zucchini seeds and two (i and iii) from squash seeds were isolated by ammonium sulphate salting out and chromatography on sp-sephadex c-25 and immobilized trypsin. the inhibitors have the same molecular mass, about 3300, contain 29 amino acids, have three disulphide bridges, and lack thr, phe and trp. the isoelectric point of the zucchini inhibitor i and squash inhibitor i is of 5.6, whereas that of the squash inhibitor iii--of 8.3. arg is the n-terminal amino acid ... | 1983 | 6868907 |
| proton nmr studies of cucurbita maxima trypsin inhibitors: evidence for ph-dependent conformational change and his25-tyr27 interaction. | a ph-dependent his25-tyr27 interaction was demonstrated in the case of cucurbita maxima trypsin inhibitors (cmti-i and cmti-iii) by means of nuclear magnetic resonance (nmr) spectroscopy. ph titration, line widths, peak shapes, deuterium exchange kinetics, and two-dimensional nuclear overhauser effect spectroscopy (noesy) were employed to characterize a conformational change involving tyr27, which was shown to be triggered by deprotonation of his25 around ph 6. a hydrogen bond is proposed to be ... | 1992 | 1731947 |
| two-dimensional nmr studies of squash family inhibitors. sequence-specific proton assignments and secondary structure of reactive-site hydrolyzed cucurbita maxima trypsin inhibitor iii. | the solution structure of reactive-site hydrolyzed cucurbita maxima trypsin inhibitor iii (cmti-iii*) was investigated by two-dimensional proton nuclear magnetic resonance (2d nmr) spectroscopy. cmti-iii*, prepared by reacting cmti-iii with trypsin which cleaved the arg5-ile6 peptide bond, had the two fragments held together by a disulfide linkage. sequence-specific 1h nmr resonance assignments were made for all the 29 amino acid residues of the protein. the secondary structure of cmti-iii*, as ... | 1992 | 1731946 |
| trypsin inhibitor iii from squash seeds (cucurbita maxima), its reactive site and proposed amino acid sequence. | the amino acid sequence of trypsin inhibitor iii isolated from squash seeds (cucurbita maxima) was established by edman degradation and standard enzymatic and chemical techniques. the inhibitor consists of 28 amino acids crosslinked by two disulfide bridges. arginine in position 5 was shown to be present at the reactive site of the inhibitor. | 1981 | 7275008 |
| calcium-binding protein in sieve tube exudate. | a calcium-binding macromolecule, with an estimated molecular weight greater than 100,000, was detected in phloem exudate from cucurbita maxima and related species. the macromolecule was a component of sieve tube sap, rather than a contaminant leached from cell walls or cut parenchyma cells during exudate collection. the protein nature of this macromolecule was deduced from its size, lability, susceptibility to proteolytic digestion, and by the dependence of calcium-binding activity on thiol-prot ... | 1981 | 24302204 |
| auxin-stimulated atpase in membrane fractions from pumpkin hypocotyls (cucurbita maxima l.). | membrane fractions from cucurbita maxima hypocotyls were isolated in a medium which inhibits the action of endogenous phospholipases. after removal of soluble phosphatases by sepharose 2b-cl column chromatography, an auxin-stimulated atpase activity was found in membrane fractions from linear sucrose gradients. in the presence of 10(-4) m phenylacetic acid (paa), the stimulation by indol-3-acetic acid (iaa) exhibited a bimodal concentration dependence with maximal stimulation of about 50% at 10( ... | 1981 | 24302108 |
| isolation and partial amino acid sequence of the trypsin inhibitor from the seeds of cucurbita maxima. | trypsin inhibitor from squash (cucurbita maxima) seed was extracted with 0.1 m-acetate buffer, ph 4.5, purified on immobilized trypsin, and separated by se-sephadex c-50 chromatography into three active fractions. all of them inhibited trypsin to the same extent, showed no antichymotrypsin or antikallikrein activity, had a similar molecular weight (about 3300), and contained no tryptophan, phenylalanine or threonine. the partial amino acid sequence of tryptic and peptic peptides of fraction iii ... | 1980 | 6791422 |
| ascorbic acid biosensor using ascorbate oxidase immobilized on alkylamine glass beads. | a biosensor for ascorbic acid based on enzyme kinetics of ascorbate oxidase (e.c.1.10.3.3) was developed. the enzyme was extracted from cucurbita maxima, or jerimun and immobilized by covalent bounding, using glutaradehyde as a bifunctional agent, on alkylamine glass beads, with and without enzyme active site protection. a low-cost, home-made oxygen electrode was applied as a transducer. the system has sensitivity from 62.5 up to 500 microm of ascorbic acid with satisfactory operation for more t ... | 2013 | 1416950 |
| cloning of a cdna encoding 1-aminocyclopropane-1-carboxylate synthase and expression of its mrna in ripening apple fruit. | 1-aminocyclopropane-1-carboxylate (acc) synthase (ec 4.4.1.14) purified from apple (malus sylvestris mill.) fruit was subjected to trypsin digestion. following separation by reversed-phase high-pressure liquid chromatography, ten tryptic peptides were sequenced. based on the sequences of three tryptic peptides, three sets of mixed oligonucleotide probes were synthesized and used to screen a plasmid cdna library prepared from poly(a)(+) rna of ripe apple fruit. a 1.5-kb (kilobase) cdna clone whic ... | 1991 | 24186277 |
| differential effect of auxin on molecular weight distributions of xyloglucans in cell walls of outer and inner tissues from segments of dark grown squash (cucurbita maxima duch.) hypocotyls. | effects of indole-3-acetic acid (iaa) on the mechanical properties of cell walls and structures of cell wall polysaccharides in outer and inner tissues of segments of dark grown squash (cucurbita maxima duch.) hypocotyls were investigated. iaa induced the elongation of unpeeled, intact segments, but had no effect on the elongation of peeled segments. iaa induced the cell wall loosening in outer tissues as studied by the stress-relaxation analysis but not in inner tissues. iaa-induced changes in ... | 1991 | 16668092 |
| the isolation and some properties of a lectin (haemagglutinin) from cucurbita phloem exudate. | the occurrence of high haemagglutinating (lectin) activity in phloem exudate from three cucurbit species is reported. the protein responsible for this lectin activity in cucurbita maxima duch. has been isolated by cation exchange chromatography on sepharose and identified by gel electrophoresis. the lectin showed agglutinating activity at concentrations as low as 0.1 μg/ml. no sugar, including those transported in the phloem of these species, interacted with agglutination. the lectin could not b ... | 1978 | 24408004 |
| a new protein inhibitor of trypsin and activated hageman factor from pumpkin (cucurbita maxima) seeds. | a protein inhibitor (cmti-v; mr 7106) of trypsin and activated hageman factor (factor xiia), a serine protease involved in blood coagulation, has been isolated for the first time from pumpkin (cucurbita maxima) seeds by means of trypsin-affinity chromatography and reverse phase high performance liquid chromatography (hplc). the dissociation constants of the inhibitor complexes with trypsin and factor xiia have been determined to be 1.6 x 10(-8) and 4.1 x 10(-8) m, respectively. the primary struc ... | 1990 | 2226848 |
| sugar composition and molecular weight distribution of cell wall polysaccharides in outer and inner tissues from segments of dark grown squash (cucurbita maxima duch.) hypocotyls. | the elongation growth of stem segments is determined by the outer cell layers (epidermis and collenchyma). we measured the sugar composition and molecular weight distribution of pectin and hemicellulose fractions obtained from inner and outer tissues of squash (cucurbita maxima duch.) hypocotyls. in addition, we studied the changes in these parameters after a 9 hour period of incubation of the segments. the results show that outer tissues have higher molecular weight pectin and hemicellulose com ... | 1990 | 16667612 |
| synthesis of p-protein in mature phloem of cucurbita maxima. | cotyledons of cucurbita maxima duch. seedlings were provided with (14)c-labeled amino acids for 12 h. besides the bulk of labeled amino acids the sieve-tube exudate also carried labeled proteins. 80% of the incorporated radioactivity was found in the p-protein, 20% in a neutral protein, and traces were found in acidic proteins after fractionation on diethyl-aminoethyl cellulose columns. the radioactive elutes were characterized by autoradiographs of both disc- and sodium dodecyl sulfate-gelelect ... | 1976 | 24424987 |
| monitoring protein cleavage and concurrent disulfide bond assignment using thermospray lc/ms. | the arrangement of the disulfide bridges of cucurbita maxima trypsin inhibitor, cmti i, has been confirmed by enzymatic and chemical cleavages of the native protein and analysis of the resulting disulfide-bridged fragments using thermospray liquid chromatography/mass spectrometry. although the disulfide bridges of cmti i have recently been assigned from the x-ray crystallographic structure, direct chemical analysis of the s-s bonds using classical techniques proved difficult. the cmti i molecule ... | 2007 | 2134058 |
| intact plastids are required for nitrate- and light-induced accumulation of nitrate reductase activity and mrna in squash cotyledons. | induction of nitrate reductase activity and mrna by nitrate and light is prevented if chloroplasts are destroyed by photooxidation in norflurazon-treated squash (cucurbita maxima l.) cotyledons. the enzyme activity and mrna can be induced if norflurazon-treated squash seedlings are kept in low-intensity red light, which minimizes photodamage to the plastids. it is concluded that induction of nitrate reductase activity and nitrate reductase mrna requires intact plastids. if squash seedlings grown ... | 1990 | 16667294 |
| nuclear magnetic resonance solution and x-ray structures of squash trypsin inhibitor exhibit the same conformation of the proteinase binding loop. | a comparison of the solution nuclear magnetic resonance (n.m.r.) structures of squash trypsin inhibitor from seeds of the squash cucurbita maxima with the x-ray structure of a trypsin complex of the inhibitor shows that the n.m.r. and x-ray structures are similar in terms of the global folding and secondary structure. the average atomic root-mean-square difference between the 36 n.m.r. structures on the one hand and the x-ray structure is 0.96 a for the backbone atoms and 1.95 a for all heavy at ... | 1989 | 2614838 |
| purification and properties of ent-kaurene synthase b from immature seeds of pumpkin. | ent-kaurene synthase b (ksb) was purified 291-fold from a crude enzyme preparation from endosperm of pumpkin (cucurbita maxima l.). separation of ent-kaurene synthase a and ksb was achieved by hydrophobic interaction chromatography. the fractions containing ksb activity were further purified by diethylaminoethyl, phenyl, and hydroxyapatite column chromatography. using sodium dodecyl phosphate-polyacrylamide gel electrophoresis, the purest enzyme preparation showed a major band at an apparent mol ... | 1995 | 12228665 |
| sieve-tube proteins from cucurbita maxima. | the two main proteins from the phloem exudate of cucurbita maxima duchesne have been isolated by ammonium-sulfate precipitation, deae-cellulose chromatography, and gel filtration, and have been characterized. they comprise about 40% each of the total protein. the amino-acid composition of these two proteins has been determined. both are highly basic with an iep above 9.5. the smaller protein has a molecular weight of ca. 30000 as determined by analytical ultracentrifugation, gel filtration, and ... | 1974 | 24442451 |
| the biosynthesis of a c19-gibberellin from mevalonic acid in a cell-free system from a higher plant. | incubation of a cell-free system from immature seeds of cucurbita maxima duch. with [(14)c]ga12-aldehyde derived from [(14)c]mevalonic acid in the same system yielded the c19-gibberellin, [(14)c]ga4, in addition to the c20-gibberellins, [(14)c]ga37, [(14)c]ga13 and [(14)c]ga43. (ga-gibberellin). | 1974 | 24442706 |
| the cucurbita maxima ribosomal dna intergenic spacer has a complex structure. | the nucleotide (nt) sequence of the 5508-nt intergenic spacer (igs), between the 25s- and the 18s-coding regions of cucurbita maxima rdna, was determined. the fragment sequenced is 6142 nt long and includes 472 nt of 25s- and 162 nt of 18s-coding regions. the igs has a complex primary structure, composed of five repetitive families (a-e) and three unique domains. it is dominated by the presence of nine, tandemly-repeating units of approximately 250 nt (repeat d), each unit containing four copies ... | 1989 | 2583512 |
| iron assimilation in plants: reduction of a ferriphytosiderophore by nadh:nitrate reductase from squash. | nadh:nitrate reductase (ec 1.6.6.1) from squash (cucurbita maxima duch., cv. buttercup) can catalyze the reduction of a ferriphytosiderophore from barley (hordeum vulgare l. cv. europa). maximal activity occurs at ph 6, with an apparentk m andv max of 76 μm and 21 nmol·min(-1)·(mg protein)(-1), respectively. the ferriphytosiderophore strongly inhibits nitrate reduction catalyzed by nitrate reductase at the optimal ph for nitrate reduction, i.e. 7.5. on the contrary, nitrate is a poor inhibitor o ... | 1988 | 24226694 |
| synthesis and biological activity of an azido derivative of paclobutrazol, an inhibitor of gibberellin biosynthesis. | a photolabile azido derivative of the kaurene oxidase inhibitor 1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-l-yl) pentan-3-ol (paclobutrazol) has been synthesized for use as a photoaffinity labeling agent. the compound was tested as an inhibitor of the oxidation of ent-kaurene catalyzed by cell-free preparations from endosperm of cucurbita maxima. the i(50) of the azido derivative was 9.5 nanomolar, which compares well with that of paclobutrazol (6.3 nanomolar in our measurements). the azid ... | 1988 | 16666477 |
| proteins of the sieve-tube exudate of cucurbita maxima. | sieve-tube exudate which appears on cut surfaces of stems of cucurbita maxima as distinct droplets has been depicted in electron micrographs of longitudinal sections of the phloem. the exudate, which was produced from mature sieve tubes only, contained filaments of p-protein, but no mitochondria or vesicles of endoplasmic reticulum. the water-soluble part of the exudate contained at least 12 proteins, as shown by disc-electrophoresis. enzymic activity was found for peroxidases, acid phosphatases ... | 1971 | 24488194 |
| molecular weights of cucurbita sieve tube proteins. | by means of sds-polyacrylamide-gel electrophoresis, molecular weights of 15000, 28000, 59000, 116000 and 220000 were determined for the main sieve tube proteins from cucurbita maxima. | 1971 | 24487555 |
| artificial tetraploids of squash (cucurbita maxima duch.). | | 1971 | 5163382 |
| phytochrome-mediated light regulation of nitrate reductase expression in squash cotyledons. | in etiolated squash (cucurbita maxima l.) cotyledons, nitrate-inducible nadh:nitrate reductase activity and protein were increased in darkness by red light pulses with red/far-red photoreversibility. continuous far-red light also led to increased levels of nitrate reductase activity and protein. poly(a)+rna, which hybridizes to squash nitrate reductase cdna, was also increased by light treatments. thus, we found that after nitrate triggering, nitrate reductase expression appears to be regulated ... | 1988 | 16666287 |
| the loss of carbon-20 in c19-gibberellin biosynthesis in a cell-free system from pisum sativum l. | the fate of the carbon-20 atom in gibberellin (ga) biosynthesis was studied in a cell-free system from pisum sativum. this carbon atom is lost at the aldehyde stage of oxidation when c20-gas are converted to c19-gas. gibberellin a12 labeled with (14)c at c-20 was prepared from [3'-(14)c]mevalonic acid with a cell-free system from cucurbita maxima and incubated with the pea system. analysis of the gas and aqueous phases showed that (14)co2 was formed at the same rate and in nearly equivalent amou ... | 1986 | 24232760 |
| different at-rich satellite dnas in cucurbita pepo and cucurbita maxima. | the at-rich highly repeated satellite dna of cucurbita pepo (zucchini) and cucurbita maxima (pumpkin) were cloned and their dna structure was investigated. dna sequencing revealed that the repeat length of satellite dna in cucurbita pepo is 349-352 base pairs. the percentage of at-base pairs is about 61%. this satellite is highly conserved in restriction enzyme pattern and dna sequence; sequence heterogeneity is about 10%. in contrast, the satellite dna of cucurbita maxima has a repeat length of ... | 1986 | 24240758 |
| an improved enzymatic synthesis of labeled gibberellin a12-aldehyde and gibberellin a12. | the biochemical synthesis of labeled gibberellin a12-7-aldehyde (ga12ald) and and gibberellin a12 (ga12) from labeled r,s-mevalonic acid (mva) using cell-free extracts from pumpkin (cucurbita maxima) endosperm has been improved over the previously reported procedure. three major improvements were developing a one-step hplc procedure to isolate ga12ald and ga12 in radiochemically pure form; adjusting the ph of the reaction mix to ph 6.9 which increased the ga12ald/ga12 ratio over that at ph 7.8 b ... | 1986 | 3754395 |
| cucurbitacin delta 23-reductase from the fruit of cucurbita maxima var. green hubbard. physicochemical and fluorescence properties and enzyme-ligand interactions. | cucurbitacin delta 23-reductase from cucurbita maxima var. green hubbard fruit displays an apparent mr of 32,000, a stokes radius of 263 nm and a diffusion coefficient of 8.93 x 10(-7) cm2 x s-1. the enzyme appears to possess a homogeneous dimeric quaternary structure with a subunit mr of 15,000. two tryptophan and fourteen tyrosine residues per dimer were found. emission spectral properties of the enzyme and fluorescence quenching by iodide indicate the tryptophan residues to be buried within t ... | 1986 | 3707515 |
| conversion of gibberellin a20 to gibberellins a 1 and a 5 in a cell-free system from phaseolus vulgaris. | the soluble fraction of a cell-free system from immature seeds of phaseolus vulgaris l. converts gibberellin a20 (ga20) to ga1 and ga5. it does however not metabolize ga1 and ga29 to ga5, showing that in this system ga20 is converted directly to ga5. the steps from ga20 to ga1 (3-hydroxylation) and from ga20 to ga5 (δ(2) double-bond formation) require oxygen, fe(2+) and α-ketoglutarate, and are stimulated by ascorbate. the enzymes catalyzing these conversions bate. the enzymes catalyzing these c ... | 1984 | 24254050 |
| subcellular localization of h(+)-atpase from pumpkin hypocotyls (cucurbita maxima l.) by membrane fractionation. | a new method of preparing sealed vesicles from membrane fractions of pumpkin hypocotyls in ethanolamine-containing buffers was used to investigate the subcellular localization of h(+)-atpase measured as nigericin-stimulated atpase. in a fluorescence-quench assay, the h(+) pump was directly demonstrated. the h(+) pump was substrate-specific for mg·atp and 0.1 mm diethylstilbestrol completely prevented the development of a δ ph. the presence of unsupecific phosphatase hampered the detection of nig ... | 1984 | 24258584 |
| subunit structure and interactions of the phloem proteins of cucurbita maxima (pumpkin). | the two major proteins from the phloem exudate of cucurbita maxima (pumpkin), pp1 and pp2, were stable in the absence of reducing agents after modification of their accessible cysteine residues with iodoacetamide. this permitted their purification without precautions to prevent oxidation. pp2, a lectin specific for oligomers of n-acetyl-d-glucosamine, was shown by sedimentation-equilibrium ultracentrifugation to be a dimer of mr of 48000. neither dithiothreitol nor tri-(n-acetyl-d-glucosamine) a ... | 1983 | 6884347 |
| cucurbitacin b delta 23-reductase from cucurbita maxima. i. assay methods, isolation and purification. | | 1968 | 5640163 |
| cucurbitacin b delta 23-reductase from cucurbita maxima. ii. cofactor requirements, enzyme kinetics, substrate specificity and other characteristics. | | 1968 | 4384331 |
| [on the soluble proteins in the water from seeds of cucurbita maxima duch]. | | 1966 | 4225958 |
| purification of squash nadh:nitrate reductase by zinc chelate affinity chromatography. | nadh:nitrate reductase (ec 1.6.6.1) was isolated and purified from the green cotyledons of 5-day-old squash seedlings (cucurbita maxima l.). the 10-hour purification procedure consisted of two steps: direct application of crude enzyme to blue sepharose and specific elution with nadh followed by direct application of this effluent to a zn(2+) column with elution by decreasing the ph of the phosphate buffer from 7.0 to 6.2. the high specific activity (100 micromoles per minute per milligram protei ... | 1983 | 16662789 |
| amino-acid sequence of two trypsin isoinhibitors, itd i and itd iii from squash seeds (cucurbita maxima). | the amino-acid sequences of two trypsin isoinhibitors, itd i and itd iii, from squash seeds (cucurbita maxima) were determined. both isoinhibitors contain 29 amino-acid residues, including 6 half cystine residues. they differ only by one amino acid. lysine in position 9 of itd iii is substituted by glutamic acid in itd i. arginine in position 5 is present at the reactive site of both isoinhibitors. the previously published sequence of itd iii has been shown to be incorrect. | 1983 | 6840699 |
| effect of pumpkin mosaic virus infection on the hill reaction and primary productivity of pumpkin (cucurbita maxima duch.) leaves. | | 1982 | 6184958 |
| calcium distribution in globoid crystals of cucurbita cotyledon protein bodies. | energy-dispersive x-ray analysis was used to investigate the location of globoid crystals with relatively high ca levels within cotyledons of cucurbita maxima, cucurbita mixta, and cucurbita andreana. the small globoid crystals in both upper and lower epidermal cells commonly contained ca. ca was present in globoid crystals of all provascular regions with the exception of the very small provascular regions of c. maxima. in c. maxima and c. mixta cotyledons, some cases were observed where ca was ... | 1979 | 16660825 |
| energy-dispersive x-ray analysis of phosphorus, potassium, magnesium, and calcium in globoid crystals in protein bodies from different regions of cucurbita maxima embryos. | the seeds of cucurbita maxima contain protein bodies with electrondense globoid crystals. because of their density globoid crystals are ideal material for energy-dispersive x-ray (edx) analysis studies of elemental composition. fixation trials were carried out to test globoid crystal extraction during glutaraldehyde fixation, water washing, and ethanol dehydration. glutaraldehyde fixation without subsequent washing or dehydration alone produced no significant changes in elemental composition of ... | 1978 | 16660439 |
| peroxidases do not move in phloem. | phloem exudates from grafts between queensland blue pumpkin (cucurbita maxima duch.) and candy red hawkesbury watermelon (citrullus vulgaris schrad.) were analysed by iso-electric focusing to detect iso-enzymes of peroxidase. these enzymes did not move in intact phloem but, when stems were cut, they surged rapidly through graft unions. | 1978 | 24413951 |
| correlation between oxygen availability, energy charge, and protein synthesis in squash cotyledons isolated from germinating seeds. | the influence of o(2) availability on the rate of protein synthesis, the levels of rna and of adenylates, and the value of the energy charge in squash (cucurbita maxima) cotyledons isolated from seeds germinated for 15 or 28 hours at different o(2) concentration (3% or 20% o(2)) has been investigated.the rate of protein synthesis is five times lower in cotyledons maintained in 3% o(2) than in those maintained in 20% o(2). also net rna synthesis is almost blocked in 3% o(2), while in 20% o(2) it ... | 1978 | 16660244 |
| a re-examination of the reputed control of cotyledonary metabolism by the axis. | a re-examination has been made of the supposed regulation by the axis of cotyledonary isocitrate lyase (ec 4.1.3.1) activity in cucumis sativas l. and cucurbita maxima duch. and greening in cucumis. when precautions are taken to ensure that isolated cotyledons and cotyledons attached to the axis have equal access to oxygen and/or water no axis effects can be observed. the results underline the importance of maintaining excised plant parts in comparable physical conditions if meaningful physiolog ... | 1976 | 24425000 |
| changes in the cotyledons of cucurbita maxima during germination. v. the nuclear envelope. | | 1975 | 1152111 |
| uptake, translocation and biotransformation of n-ethyl perfluorooctanesulfonamide (n-etfosa) by hydroponically grown plants. | n-ethyl perfluorooctane sulfonamide (n-etfosa) is an important perfluorooctanesulfonate (pfos) precursor (prefos) which is used in sulfluramid. the present work studied the uptake, translocation and metabolism of n-etfosa in wheat (triticum aestivum l.), soybean (glycine max l. merrill) and pumpkin (cucurbita maxima l.) by hydroponic exposure. except for parent n-etfosa, its metabolites of perfluorooctane sulfonamide acetate (fosaa), perfluorooctane sulfonamide (pfosa), pfos, perfluorohexane sul ... | 2018 | 29306808 |