Intracellular localisation of some peptidases and α‐mannosidase in cotyledons of resting kidney bean, <i>Phaseolus vulgaris</i>

Mikkonen, Anu; Begbie, R.; Grant, G.; Pusztai, Á.

doi:10.1111/j.1399-3054.1986.tb06598.x

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…Protein storage vesicles were isolated from mature aleurone layers as in Mikkonen et al (1986). Briefly, de-embryonated barley seeds were surface-sterilized and incubated in moist quartz sand for 3 d. The aleurone layers were isolated with a scalpel, dried in a desiccator for 3 d, and grounded in a mortar with anhydrous glycerol.…”

Section: Methodsmentioning

confidence: 99%

A barley (Hordeum vulgare L.) LEA3 protein, HVA1, is abundant in protein storage vacuoles

Marttila

Tenhola

Mikkonen

1996

Planta

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Abstract. The HVAI protein belongs to the LEA3 group, which is expressed during the late stage of seed maturation. It is also induced by exogenous abscisic acid (ABA) and a variety of environmental stresses in germinating barley (Hordeum vulgare L.). In the present work, the potential role of HVA! was investigated by studying its tissue distribution and subcellular localization in mature and stressed seeds by immuno-microscopic methods. In the mature seed, HVA1 protein was detected in all tissues except the non-living starchy endosperm. During germination the amount of HVA 1 protein decreased but did not totally disappear. Incubation with 100/aM ABA, cold treatment or drought stress dramatically increased HVA1 expression in the germinated seed. In this work, the distribution of a LEA3 group protein was studied in a cereal seed for the first time by immuno-electron microscopy. In the scutellum and aleurone layer, HVA1 was localized both in the cytoplasm and protein storage vacuoles (PSVs). HVA1 protein was found to be threefold more abundant in PSVs than in the cytoplasm of an unstressed seed tissue. The ratio increased with ABA or stress treatments to at least ninefold. The role of HVA1 in PSVs remains unclear: a previously suggested possibility is ion sequestration to prevent precipitation during stress. On the other hand, HVA1 protein could also be degraded in PSVs. HVA1 protein does not have the signal peptide typical of proteins which are glycosylated and targeted into the vacuole via the Golgi complex. Because HVA1 is not glycosylated, it may use an alternative, ER-independent vacuolar pathway, also found in yeast cells.

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Section: Methodsmentioning

confidence: 99%

A barley (Hordeum vulgare L.) LEA3 protein, HVA1, is abundant in protein storage vacuoles

Marttila

Tenhola

Mikkonen

1996

Planta

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“…In the quiescent seed, proteases coexist with storage proteins in the protein bodies (St Angelo et al 1969, Mikkonen et al, 1986. Protein hydrolysis does not immediately follow seed imbibition (Tan- Wilson and Wilson 1982), which implies that proteases are inhibited by natural inhibitors, A remarkable property of quiescent seeds is that they are able to survive in the latent state.…”

Section: Introductionmentioning

confidence: 99%

Proteolysis in the quiescent seed

Duarte

Ricardo²,

Duque-Magalhães

1996

Physiologia Plantarum

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The importance of the proteolytic system of the quiescent seed in regard to mobilization of storage protein was assessed by identification of proteases already present at this stage. Extracts of quiescent cotyledons of white lupin (Lupinus albus) submitted to 45 h autolysis in vitro displayed a higher degree of protein degradation than that observed in vivo after two days of seed imbibition. Differences in the susceptibility to proteolysis were verified by densitometric analysis of the polypeptides after electrophoretic separation. The pH dependence of the proteolytic activities and the responses to specific protease inhibitors showed that the proteolytic systems vary from quiescent to 1 ‐ to 3‐day‐imbibed cotyledons. By labelling an endogenous globulin with 125I a sensitive radiometric assay allowed the identification of both an acidic and a neutral proteolytic system in the quiescent cotyledon. Within the quiescent seed there already exists a high potential for initiating proteolysis, so that the requirement for proteolysis by specific endopeptidases synthesized de novo upon imbibition only applies to part of the reserve proteins.

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The presence and inactivation of trypsin inhibitors, tannins, lectins and amylase inhibitors in legume seeds during germination. A review

Savelkoul¹,

Poel²,

Tamminga³

1992

Plant Food Hum Nutr

105

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During the germination of legume seeds, enzymes become active in order to degrade starch, storage-protein and proteinaceous antinutritional factors. The degradation of storage-protein is necessary to make peptides and amino acids available in order to stimulate seed growth and early plant growth. Proteinaceous antinutritional factors such as amylase inhibitors, lectins and trypsin inhibitors are present in legume seeds and protect them against predators. However, during germination, they degrade to a lower level by the action of several enzymes. The effect of germination on the content and activity of amylase inhibitors, lectins, tannins and trypsin inhibitors is discussed.

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Intracellular localisation of some peptidases and α‐mannosidase in cotyledons of resting kidney bean, Phaseolus vulgaris

Cited by 5 publications

References 12 publications

A barley (Hordeum vulgare L.) LEA3 protein, HVA1, is abundant in protein storage vacuoles

A barley (Hordeum vulgare L.) LEA3 protein, HVA1, is abundant in protein storage vacuoles

Proteolysis in the quiescent seed

The presence and inactivation of trypsin inhibitors, tannins, lectins and amylase inhibitors in legume seeds during germination. A review

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