Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “tuber”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed2003

Structural diversity and organization of three gene families for Kunitz-type enzyme inhibitors from potato tubers (Solanum tuberosum L.).

In the potato, Kunitz-type enzyme inhibitors are abundant and highly polymorphic small proteins found in tubers. DNA sequence analysis of 1596 unselected ESTs (expressed sequence tags) from mature tubers of the cultivars Provita and Saturna resulted in the identification of 55 different DNA sequences with high sequence similarity to Kunitz-type enzyme inhibitors. The frequency of Kunitz-type inhibitor ESTs in Provita was four times higher than in Saturna tubers, and none of the Provita ESTs was identical to any of the Saturna ESTs. A phenogram constructed from the deduced amino acid sequences of the inhibitors revealed three major homology groups-A, B and C. Group A inhibitors were all derived from Provita ESTs. Inhibitor groups A and B were more similar to each other than to group C inhibitors, and for most members within-group similarity was at least 90%. Non-conservative amino acid substitutions and insertion/deletion polymorphisms suggest functional differentiation between members of the gene family. A minimum of 21 genes for Kunitz-type enzyme inhibitors (six for group A, nine for group B and six for group C) was estimated to exist in the potato genome. Genetic mapping and the identification of BAC (bacterial artificial chromosome) clones containing more than one member of the gene family indicated that most inhibitor genes of groups A, B and C are organized in a cluster that maps to a single region on potato chromosome III.

Amino Acid Sequence↗
PubMed2003

Characterization of a wound-inducible cytochrome P450 gene ( CYP72A29) that is down-regulated during crown gall tumorigenesis in potato tuber.

A cDNA for a putative cytochrome P450 (CYP72A29), which is down-regulated during Agrobacterium tumefaciens -mediated tumorigenesis, was isolated from potato ( Solanum tuberosumL. May Queen) tuber by differential display. Northern analysis indicated that the CYP72A29 gene was transiently up-regulated in tuber discs after a 24-h aging period, and expression gradually increased upon further incubation (up to 7 days). Inoculation of tuber discs with the non-pathogenic A. tumefaciens strain LBA4301 had a very similar effect, but inoculation with the wild-type strain A. tumefaciens A208 suppressed the accumulation of mRNA during further incubation. Furthermore, the accumulation of CYP72A29 mRNA was strongly suppressed by inoculation with mutant strains of A. tumefaciens that produce large amounts of indole-3-acetic acid. This down-regulation also occurred when the discs were treated with 2,4-dichlorophenoxyacetic acid or 1-naphthalenacetic acid. These results suggest that the expression of CYP72A29 is regulated by auxin. RT-PCR analysis revealed that the transcripts were most abundant in sprouts and eyes, less so in roots, and hardly detectable in leaves, flower buds and stems.

Agrobacterium tumefaciens↗
PubMed2006

Identification and kinetic characterization of HtDTC, the mitochondrial dicarboxylate-tricarboxylate carrier of Jerusalem artichoke tubers.

Jerusalem artichoke (Helianthus tuberosus L.) tubers were reported to be tolerant to cold and freezing. The aim of this study was to perform a kinetic characterization of the mitochondrial dicarboxylate-tricarboxylate carrier (HtDTC) and to assess a possible involvement of this carrier in the cold tolerance of tubers. The HtDTC was purified from isolated mitochondria by sequential chromatography on hydroxylapatite/celite and Matrex Gel Orange A. SDS gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 31.6 kDa. A polyclonal antibody raised against the tobacco DTC cross-reacted with the purified protein on Western blot analysis. In gel trypsin, digestion of the purified HtDTC yielded peptides that exhibited strong amino acid sequence similarity to previously identified plant DTCs. Furthermore, using degenerate primers, a portion of the Htdtc cDNA was amplified and sequenced; this cDNA encoded for a protein with high sequence similarity to known plant homolog DTCs. When reconstituted in liposomes loaded with dicarboxylate (2-oxoglutarate, malate, malonate, succinate, and maleate) or tricarboxylate anions (citrate, trans-aconitate, and isocitrate), the purified HtDTC transported all these anions in exchange with external [14C]2-oxoglutarate. A kinetic characterization of HtDTC was performed: (a) the half-saturation constant Km and the Vmax at 25 degrees C of the 2-oxoglutarate/2-oxoglutarate exchange by reconstituted HtDTC were found to be 360 microM and 10.9 micromol/(min mg protein), respectively; (b) the activation energy Ea of the succinate/2-oxoglutarate exchange by the reconstituted HtDTC was found to be 50.7 kJ/mol constant between -5 and 35 degrees C. Similarly, the activation energy Ea of succinate respiration of isolated Jerusalem artichoke mitochondria, measured between -2 and 35 degrees C, was shown to be constant (65.3 kJ/mol). The physiological relevance of kinetic properties and temperature dependence of transport activities of HtDTC is discussed with respect to the cold tolerance ability of Jerusalem artichoke tubers.

Amino Acid Sequence↗
PubMed2006

Expression of the cry9Aa2 B.t. gene in tobacco chloroplasts confers resistance to potato tuber moth.

We report here the control of potato tuber moth (Phthorimaea operculella) by incorporating a truncated Bacillus thuringiensis cry9Aa2 gene in the plastid genome. Plasmids pSKC84 and pSKC85 are derivatives of a new polycistronic plastid transformation vector, pPRV312L, that carries spectinomycin resistance (aadA) as a selective marker and targets insertions in the trnI-trnA intergenic region. The Cry9Aa2 N-terminal region (82.1 kDa; 734 amino acids) was expressed in a cassette, which consists of 49 nucleotides of the cry9Aa2 leader and the 3'-untranslated region of the plastid rbcL gene (TrbcL), and relies on readthrough transcription from the plastid rRNA operon. In a tobacco leaf bioassay, expression of Cry9Aa2 conferred resistance to potato tuber moth. In accordance, the Cry9Aa2 insecticidal protein accumulated to high levels, approximately 10% of the total soluble cellular protein and approximately 20% in the membrane fraction. However, high-level Cry9Aa2 expression significantly delayed plant development. Thus, a practical system to control potato tuber moth by Cry9Aa2 expression calls for down-regulation of its expression.

Animals↗
PubMed1988

Molecular characterization of four forms of phosphofructokinase purified from potato tuber.

Four forms of phosphofructokinase (PFK) have been purified to apparent homogeneity from tubers of potato (Solanum tuberosum cv. Record). Each had a final specific activity of about 200 mumol.min-1.mg-1 protein. Similar forms of PFK were found in partially purified extracts from tubers and leaves of other potato cultivars and related wild species. The relative molecular masses of three forms of PFK were about 200,000 whereas that of the fourth PFK was greater than 800,000. The four forms of PFK contained different proportions of four polypeptides which had apparent relative molecular masses of 46,300, 49,500, 50,000, and 53,000. These polypeptides gave different patterns of peptide fragments after chemical and proteolytic cleavage. Western blots and immunoprecipitation studies using antibodies raised against the individual polypeptides showed that all four are associated with PFK. Thus, potato tubers contain four distinct forms of PFK that differ in their subunit composition.

Antibody Formation↗
PubMed1976

Cytochrome c dependent, antimycin-A resistant respiration in mitochondria from potato tuber (Solanum tuberosum L.). Influence of wounding and storage time on outer membrane NADH-cytochrome-c-reductase.

Cytochrome c has two stimulatory effects on respiration of mitochondria especially those from wounded potato tuber. In the first place a stimulation of succinate- and NADH-consuming, antimycin-A-sensitive respiration, which reaches a maximal value at low cytochrome c concentrations, has been found. In the second place, at higher concentrations of cytochrome c a stimulation of NADH-consuming respiration occurs, which is antimycin-A-resistant, but KCN-sensitive. This antimycin-A-resistant, NADH-consuming respiration is absent, when no cytochrome c is added to the reaction medium. It is insensitive to metal chelators, to which the antimycin-A-and KCN-resistant plant mitochondrial alternative oxidase is sensitive. By measurements of NADH-cytochrome c reductase activities a corresponding antimycin-A-resistant NADH-cytochrome c reductase has been found, which is insensitive to osmotic shock treatment. A localization of this antimycin-A-resistant electron transport with NADH as the electron donor in the outer mitochondrial membrane is likely. In the mitochondrial preparations cytochrome c might stimulate by acting as an electron-carrier between the outer membrane reductase and the inner membrane cytochrome oxidase. A big increase of the outer membrane mediated electron transport in the mitochondria has been observed after wounding of potato tuber tissue. The ability of the tissue to produce this electron transport pathway after wounding disappeared after prolonged storage of the tubers. A possible function of this electron transport pathway in fatty acid desaturation during the wound-reaction is suggested.

Antimycin A↗
PubMed1996

Purification of polyphenol oxidase free of the storage protein patatin from potato tuber.

Routine protein purification to homogeneity from potato tuber, as from other storage tissues and seeds, is often hindered due to the large amounts of storage protein present. In potato, patatin, the major storage protein of the tuber, often contaminates preparations. The present work describes the purification of polyphenol oxidase (PPO) from the potato tuber (Solanum tuberosum cv Cara) to homogeneity including the critical step of hydrophobic chromatography on Octyl-Sepharose which was sufficient to completely remove patatin. The purified PPO was found to be a doublet of M(r) 60,000 and 69,000 when analysed by SDS-PAGE with a Km 4.3 +/- 0.3 mM for L-dihydroxyphenylalanine. Both bands were found to have similar N-terminal corresponding to PPO isoforms when sequenced.

Amino Acid Sequence↗
PubMed2004

Liquid chromatography-mass spectrometry identification of anthocyanins of isla oca (Oxalis tuberosa, Mol.) tubers.

High-performance liquid chromatography (HPLC)-diode array detection (DAD)-mass spectrometry (MS) techniques have been successfully employed in the identification of the anthocyanins of the coloured tubers of isla oca (Oxalis tuberosa), the second most cultivated tuber in the Andean region. Tubers underwent a pre-treatment step in order to inhibit enzymatic reactions and to obtain a stable powder or "concentrate". This concentrate was dissolved, purified and then analysed. Eight different compounds were found. The major peaks were malvidin glucosides (malvidin 3-O-glucoside and 3,5-O-diglucoside). The rest of the peaks were 3,5-O-diglucosides of petunidin and peonidin, and 3-O-glucosides of delphinidin, petunidin and peonidin. Only malvidin 3-O-acetylglucoside-5-O-glucoside was found as an acylated anthocyanin.

Anthocyanins↗
PubMed2005

High-performance liquid chromatography-diode array detection assay for the detection and quantification of the Beauveria metabolite oosporein from potato tubers.

A high-performance liquid chromatography-diode array detection (HPLC-DAD) assay is described for the detection and quantification of the secreted Beauveria brongniartii metabolite oosporein from potato tubers. Analyte recovery was achieved with a Britton-Robinson buffer system at pH 5.5 diluted with methanol 3:7 (v/v) (BR5.5-MeOH). An internal standard protocol using 2-iodobenzoic acid was established to minimize analytical error. The resulting assay, using a binary solvent gradient with acidic modifiers and detecting the metabolite at 287 nm, showed a limit of detection (LOD) of 2.4 mg oosporein/kg potato tubers. The oosporein content of potato tuber samples obtained from a field trial using the biological pest control B. brongniartii formulation Melocont-Pilzgerste in up to five-fold higher doses (250 kg Melocont-Pilzgerste/ha) as recommended per year was found to be below the established LOD.

Ascomycota↗
PubMed2004

Rhamnogalacturonan I in Solanum tuberosum tubers contains complex arabinogalactan structures.

A rhamnogalacturonan I polysaccharide was isolated from potato (Solanum tuberosum cv. Posmo) tuber cell walls and characterised by enzymatic digestion with an endo-beta-1 --> 4-galactanase and an endo-alpha-1 --> 5-arabinanase, individually or in combination. The reaction products were separated using size-exclusion chromatography and further analysed for monosaccharide composition and presence of epitopes using the LM5 anti-beta-1 --> 4-galactan and LM6 anti-alpha-1 --> 5-arabinan monoclonal antibodies. The analyses point to distinct structural features of potato tuber rhamnogalacturonan I, such as the abundance of beta-1 --> 4-galactan side chains that are poorly substituted with short arabinose-containing side chains, the presence of alpha-1 --> 5-arabinan side chains substituted with beta-1 --> 4-galactan oligomers (degree of polymerisation > 4), and the presence of alpha-1 --> 5-arabinans that resist enzymatic degradation. A synergy between the enzymes was observed towards the degradation of arabinans but not towards the degradation of galactans. The effect of the enzymes on isolated RG I is discussed in relation to documented effects of enzymes heterologously expressed in potato tubers. In addition, a novel and rapid method for the determination of the monosaccharide and uronic acid composition of cell wall polysaccharides using high-performance anion exchange chromatography with pulsed amperometric detection is described.

Cell Wall↗
PubMed1996

The tuberous breast deformity: classification and treatment.

To date there are many descriptive terms for the tuberous breast deformity but there is no widely accepted nomenclature. A retrospective study was undertaken of 68 tuberous breasts and the operative corrections performed. The deformities were classified into four types. Type I (hypoplasia of the lower medial quadrant), type II (hypoplasia of the lower medial and lateral quadrants, sufficient skin in the subareolar region), type III (hypoplasia of the lower medial and lateral quadrants, deficiency of skin in the subareolar region) and type IV (severe breast constriction, minimal breast base). Areolar prolapse, usually regarded as a major symptom, was only found in 30 (44%) deformed breasts. Postoperative review of 51 breasts in 31 patients showed that type I cases treated by reduction mammaplasty of adequately sized breasts or augmentation of hypoplastic breasts had excellent results. These procedures with additional spreading of the breast tissue in type II deformities give good results. Severe cases (types III and IV) treated by augmentation and tissue spreading procedures have an unsatisfactory shape and have a 'second crease' deformity. For types III and IV, additional skin in the subareolar region by tissue expansion or flap procedures is necessary. There is no one method to correct 'the' tuberous breast but there are many procedures which should be used according to the type of deformity. The classification developed could end the confusion in nomenclature.

Breast↗
PubMed1997

Direct detection of potato leafroll virus in potato tubers by immunocapture and the isothermal nucleic acid amplification method NASBA.

NASBA, an isothermal amplification method for nucleic acids, was applied to the detection of RNA of potato leafroll virus (PLRV) in a single enzymatic reaction at 41 degrees C. A set of primers was selected from the coat protein open reading frame sequence of PLRV to allow amplification of viral RNA. The NASBA reaction products were visualized after electrophoresis by ethidium bromide or acridine orange staining. The specificity of the amplification products was validated by Northern blot analysis with a PLRV-specific 32P-labelled oligonucleotide probe. The procedure was coupled to immunocapture of PLRV virions from tuber extracts by immobilized antibodies in microtubes. It was possible to discriminate readily by this method between uninfected and primarily PLRV-infected potato tubers. NASBA is suitable for the direct detection of PLRV in potato tubers from primarily infected plants, offering the potential to considerably simplify the inspection of seed-potatoes for virus infection.

Animals↗
PubMed1998

A mixture of synthetic oligonucleotide probes labeled with biotin for the sensitive detection of potato spindle tuber viroid.

Five kinds of synthetic oligonucleotide probes labeled with biotin (BIO) were designed for the detection of potato spindle tuber viroid (PSTVd), and their sensitivities were compared with that of a digoxigenin (DIG)- or BIO-labeled cDNA probe. Although each oligonucleotide probe alone was less sensitive than the DIG-cDNA probe, sensitivity was increased by using a mixture of two or all of the five oligonucleotide probes. The sensitivity of a PSmix1-5 probe, which was a mixture of five oligonucleotides, was the same as that of a DIG-labeled cDNA probe, which can detect 7.8 pg of purified PSTVd and PSTVd in nucleic acids, equivalent to extracts from 20 microg of infected potato leaf and 310 microg of infected potato tuber. Using the PSmix1-5 probe, PSTVd in all leaves and tubers of seven potato cultivars could be detected without any background. Moreover, with the PSmix1-5 probe, the hybridization time could be shortened to 2 h without any decrease in sensitivity, whereas the sensitivity of the cDNA probes clearly decreased when the hybridization time was shortened. Hybridization using a mixture of several oligonucleotide probes may be applicable to the gene diagnosis of other viroids and viruses.

Base Sequence↗
PubMed2002

Potato tubers as bioreactors for palatinose production.

Palatinose (isomaltulose, 6-O-alpha-D-glucopyranosyl-D-fructose) is a structural isomer of sucrose with very similar physico-chemical properties. Due to its non-cariogenicity and low calorific value it is an ideal sugar substitute for use in food production. Palatinose is produced on an industrial scale from sucrose by an enzymatic rearrangement using immobilized bacterial cells. To explore the potential of transgenic plants as alternative production facilities for palatinose, a chimeric sucrose isomerase gene from Erwinia rhapontici under control of a tuber-specific promoter was introduced into potato plants. The enzyme catalyses the conversion of sucrose into palatinose. Expression of the palI gene within the apoplast of transgenic tubers led to a nearly quantitative conversion of sucrose into palatinose. Despite the soluble carbohydrates having been altered within the tubers, growth of palI expressing transgenic potato plants was indistinguishable from wild type plants. Therefore, expression of a bacterial sucrose isomerase provides a valid tool for high level palatinose production in storage tissues of transgenic crop plants.

Bioreactors↗
PubMed2000

Involvement of sucrose synthase in sucrose synthesis during mobilization of fructans in dormant Jerusalem artichoke tubers.

The relative contribution of sucrose synthase and sucrose-phosphate synthase to sucrose synthesis in dormant tubers of Jerusalem artichokes was determined. Feeding dormant tubers alternatively with mixtures of [14C]glucose and unlabeled fructose, and [14C]glucose and [14C]fructose has shown that sucrose synthase contributes ca. 95-97% to sucrose synthesis. This is the first report of sucrose synthesis in Jerusalem artichokes dormant tubers.

Journal Article↗
PubMed2005

[Tuberous angioma in an infant: a case study].

Tuberous angioma of the orbit is the most frequent benign tumor of the orbit in children. Angiomatous tumors in general, and more particularly tuberous angioma tumors, are classed among the primary tumors of the orbit. They are by far the most frequent. The author reports the clinical observation of a giant tuberous angioma the entire left lower eyelid radiating throughout the left cheek of a 2-month-old infant. This case underscores the benefit of clinical symptomatology in the diagnostic procedure and the problems encountered in therapeutic management of these tumors located in the so-called noble zones, which sometimes affect infants in the first months of life.

Eyelid Neoplasms↗
PubMed2003

Cassava (Manihot esculenta) leaf and tuber concentrate in diets for broiler chickens.

Experiment 1 was conducted to determine the nutritive quality of cassava tuber leaf concentrate prepared either by mixing cassava tubers and leaves together before grinding or grinding them separately before mixing. Three mixing proportions of 50:50, 60:40 and 80:20 were used. Samples were subjected to either sundrying or oven drying. Physical examination of samples, proximate analysis and cyanide content of each of the samples were determined. In experiment 2 the sample of highest nutritive value was selected for inclusion in four diets at levels of 0%, 10%, 20% and 30% respectively. A total of 120 day-old broilers were divided into four groups and each group further into three subgroups. The four experimental diets were fed to each of the groups for a period of 9 weeks. Growth parameters, carcass characteristics and haematological parameters were also determined. Results showed that in experiment 1 the grinding together of cassava tubers and leaves in the proportion of 50:50 before sun-drying gave the best texture, highest CP content with low HCN content. Inclusion of 10% cassava concentrate gave good performance in terms of growth and feed conversion, with no detrimental effects on haematological parameters and carcass characteristics.

Animal Feed↗
PubMed2002

A high-affinity ammonium transporter from the mycorrhizal ascomycete Tuber borchii.

An ammonium transporter cDNA, named TbAMT1, was isolated from the ectomycorrhizal ascomycetous truffle Tuber borchii. The polypeptide encoded by TbAMT1 (52 kDa) functionally complements ammonium uptake-defective yeast mutants and shares sequence similarity with previously characterized ammonium transporters from Saccharomyces (Mep) and Arabidopsis (AtAMT1). Structural characteristics common to the Mep/Amt family and peculiar features of the Tuber transporter have been evidenced by a detailed topological model of the TbAMT1 protein, which predicts 11 transmembrane helices with an N terminus(OUT)/C terminus(IN) orientation. As revealed by uptake/competition experiments conducted in yeast, TbAMT1 is a high-affinity transporter with an apparent K(m) for ammonium of 2 microM. The TbAMT1 mRNA was very slowly, yet specifically upregulated in nitrogen-deprived T. borchii mycelia. Instead, a much faster return to basal expression levels was observed upon resupplementation of either ammonium or nitrate, which thus appear to be utilized as equally effective nitrogen sources by Tuber mycelia.

Amino Acid Sequence↗