Changes of Cyanide Content and Linamarase Activity in Wounded Cassava Roots

Kojima, Mineo; Iwatsuki, Norio; Data, Emma S.; Villegas, Cynthia Dolores V.; Uritani, Ikuzô

doi:10.1104/pp.72.1.186

Cited by 26 publications

(21 citation statements)

References 9 publications

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“…We established that the total cyanide content was high in the cortex and decreased sharply towards the center of the root in each variety. These results are complied with those achieved by [29,25] who showed that along the proximal to the distal end, the cyanide content decreases sharply. Our results suggest that it is safe to remove or exclude the cortex portion before eating the root.…”

Section: Total Cyanide Contents In Cassava Slices (1/4 1/2 3/4) Andsupporting

confidence: 80%

Assessment of Cyanide Content in Cassava (Manihot esculenta Crantz) Varieties and Derived Products from Senegal

Guédé¹

2013

IJNFS

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Abstract:We investigated cyanide levels in four cassava varieties and some derived products from Senegal. The study was conducted on fresh tubers by sampling in three longitudinal positions (1/4; 1/2; 3/4) and four radials (A, B, C and D). In addition, the sampling of derived products was carried out by product types (chip dried, graded, unpressed and pressed attieke, gari and flour). Cyanide contents were determined using differential pulse polarography. Results showed that whatever the variety considered, there was no significant difference between the total HCN content in cassava slices (1/4; 1/2; 3/4). Similarly, results from different layers (A, B, C and D) did not highlight the radial variability of the total HCN content. We showed a variable cyanide content (mg HCN/kg fresh material) in cassava varieties: 104.3 ± 3.9; 171.6 ± 5.4; 231.2 ± 10.2; 270.8 ± 12.0 for Kombo, Nigeria, Soya and Gniargui respectively. The detoxification processes (attieke, gari and flour) indicated a reduction rate in excess of 80% and may be effective to reduce the cyanide content in cassava root down to a tolerable level (< 50 mg/kg).

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Section: Total Cyanide Contents In Cassava Slices (1/4 1/2 3/4) Andsupporting

confidence: 80%

Assessment of Cyanide Content in Cassava (Manihot esculenta Crantz) Varieties and Derived Products from Senegal

Guédé¹

2013

IJNFS

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“…1 was further confirmed by immunoblotting after two-dimensional SDS-PAGE (Fig. 4) (13). In common with linamarases from Phaseolus lunatus and Trifolium repens (6,11), cassava linamarase resides in the cell wall (20).…”

Section: But Left Peptidementioning

confidence: 85%

“…Therefore, it is generally assumed that these cyanogens and their catabolic enzymes are localized in the intact plant in different compartments and come into contact with each other upon tissue disruption. Although only limited information is currently available, examples of compartmentation at both tissue and subcellular levels are known (13,14). To broaden our knowledge of how compartmentation normally prevents premature and suicidal cyanogenesis in undamaged plants, our laboratory is investigating the mature seeds of black cherry (Prunus serotina Ehrh.)…”

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confidence: 99%

Immunocytochemical Localization of Mandelonitrile Lyase in Mature Black Cherry (Prunus serotina Ehrh.) Seeds

Poulton²

1991

Plant Physiol.

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Mandelonitrile lyase (MDL, EC 4.1.2.10), which catalyzes the reversible dissociation of (R)-(+)-mandelonitrile to benzaldehyde and hydrogen cyanide, was purified to apparent homogeneity from mature black cherry (Prunus serotina Ehrh.) seeds by conventional protein purification techniques. This flavoprotein is monomeric with a subunit molecular mass of 57 kilodaltons. Glycoprotein character was shown by its binding to the affinity matrix concanavalin A-Sepharose 4B with subsequent elution by a-methyl-D-glucoside. Upon chemical deglycosylation by trifluoromethanesulfonic acid, the molecular mass was reduced to 50.9 kilodaltons. Two-dimensional gel analysis of deglycosylated MDL revealed the presence of several subunit isoforms of similar molecular mass but differing slightly in isoelectric point. Polyclonal antibodies were raised in New Zealand white rabbits against deglycosylated and untreated MDL. Antibody titers were determined by enzyme linked immunosorbent and dot immunobinding assays, while their specificities were assessed by Western immunoblot analysis. Antibodies raised against untreated Iyase recognized several proteins in addition to MDL. In contrast, antisera raised against deglycosylated MDL were monospecific and were utilized for developmental and immunocytochemical localization studies. SDS-PAGE and immunoblotting analysis of seed proteins during fruit maturation showed that MDL first appeared in seeds shortly after cotyledons began development. In cotyledon cells of mature seeds, MDL was localized primarily in the cell wall with lesser amounts in the protein bodies, whereas in endosperm cells, this labeling pattern was reversed. N-terminal sequence data was gathered for future molecular approaches to the question of MDL microheterogeneity.Cyanogenesis, the production of the respiratory poison HCN3 by biological organisms, was first described in plants almost two Enzyme Assay MDL activity was measured spectrophotometrically by monitoring the conversion of (R,S)-mandelonitrile to benzaldehyde and HCN by the increase in absorbance at 249.6 nm (3 1). Protein EstimationProtein content was estimated by the Bradford procedure (2) with BSA serving as standard. Deglycosylation of MDLChemical deglycosylation of MDL was performed using TFMS as described by Edge et al. (5). The deglycosylated protein was recovered by extraction into aqueous phase followed by overnight dialysis against 4 L of 2 mm pyridine acetate buffer, pH 5.5. The dialyzed preparation was concentrated by ultrafiltration (Amicon Minicon) to approximately 1 mL and stored at -20°C. Generation of Polyclonal Antibodies against MDLBefore immunization ofanimals, homogeneous MDL, with or without prior deglycosylation, was subjected to two-dimensional PAGE (IEF range pH 4-6.5, followed by 10% SDS-PAGE). Areas containing MDL were excised and electroeluted into 10 mm Tris-acetate buffer (pH 6.8 LOCALIZATION OF PRUNUS SEROTINA MANDELONITRILE LYASE alkaline phosphatase-conjugated goat anti-rabbit IgG (diluted 1:1000 with blocking solution) for ...

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“…By 6) were subjected to SDS-PAGE. Proteins were either stained by Brilliant Blue G-Colloidal (lanes 1-3) or electroblotted onto nitrocellulose and immunodecorated with affinity purified anti-AH antiserum (lanes [4][5][6]. B, Aliquots (7.5 contrast, PH was absent from the more internal procambial cells, including those housing AH, and from the bundle sheath and cotyledonary storage parenchyma.…”

Section: Immunolocalization Of Ah and Ph By Light Microscopymentioning

confidence: 99%

“…It is therefore assumed that amygdalin and its catabolic enzymes are kept separate in undamaged cherry seeds by some means of compartmentation (15). In sorghum leaves, premature cyanogenesis is prevented by compartmentation at the tissue level (7), whereas subcellular compartmentation seems more likely in other vegetative systems (2,6,13). How cyanogenic seed tissues, such as those found in Prunus species, prevent untimely HCN release remains largely unknown (19).…”

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confidence: 99%

Tissue and Subcellular Localization of Enzymes Catabolizing (R)-Amygdalin in Mature Prunus serotina Seeds

Swain¹,

Li²,

Poulton³

1992

Plant Physiol.

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In black cherry (Prunus serotina Ehrh.) homogenates, (R)-amygdalin is catabolized to HCN, benzaldehyde, and D-glucose by the sequential action of amygdalin hydrolase, prunasin hydrolase, and mandelonitrile lyase. The tissue and subcellular localizations of these enzymes were determined within intact black cherry seeds by direct enzyme analysis, immunoblotting, and colloidal gold immunocytochemical techniques. Taken together, these procedures showed that the two d-glucosidases are restricted to protein bodies of the procambium, which ramifies throughout the cotyledons. Although amygdalin hydrolase occurred within the majority of procambial cells, prunasin hydrolase was confined to the peripheral layers of this meristematic tissue. Highest levels of mandelonitrile lyase were observed in the protein bodies of the cotyledonary parenchyma cells, with lesser amounts in the procambial cell protein bodies. The residual endosperm tissue had insignificant levels of amygdalin hydrolase, prunasin hydrolase, and mandelonitrile lyase.

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Changes of Cyanide Content and Linamarase Activity in Wounded Cassava Roots

Cited by 26 publications

References 9 publications

Assessment of Cyanide Content in Cassava (Manihot esculenta Crantz) Varieties and Derived Products from Senegal

Assessment of Cyanide Content in Cassava (Manihot esculenta Crantz) Varieties and Derived Products from Senegal

Immunocytochemical Localization of Mandelonitrile Lyase in Mature Black Cherry (Prunus serotina Ehrh.) Seeds

Tissue and Subcellular Localization of Enzymes Catabolizing (R)-Amygdalin in Mature Prunus serotina Seeds

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