The Presence of Protease‐digestible Material in Golgi Vesicles During Endosperm Development of Selected Cereals

Bechtel, Donald B.; Gaines, Ronald L.

doi:10.1002/j.1537-2197.1982.tb13331.x

Cited by 6 publications

(7 citation statements)

References 11 publications

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“…Previously, we have shown ' for wheat and other cereals that the Golgi vesicles contents are protease digestible (Bechtel and Gaines, 1982). In addition, we have shown that the protein granules are protease digestible (Bechtel et al, 1982). We have been able to demonstrate the presence of Golgi apparatus in wheat starchy endosperm until 28 DAF (in which 34 DAF is maturity, the harvest date).…”

Section: Discussionmentioning

confidence: 59%

“…The results of this study indicated that the Golgi apparatus began to secrete electron-opaque vesicles at the time of protein body initiation. Previously, we have shown ' for wheat and other cereals that the Golgi vesicles contents are protease digestible (Bechtel and Gaines, 1982). In addition, we have shown that the protein granules are protease digestible (Bechtel et al, 1982).…”

Section: Discussionmentioning

confidence: 90%

“…4(h)-(j)]. (4) The fourth mechanism of enlargement becoming prominent later in development involved fusion of the membrane of two or more protein bodies with subsequent fusion of their protein granules to form a large protein mass which eventually became the protein matrix (Bechtel et al, 1982).…”

Section: Protein Body Initiationmentioning

confidence: 99%

“…Recently, Parker (1981) has also reported the presence of Golgi apparatus up to at least 40 days past anthesis. Bechtel and Gaines (1982) have shown that the Golgi apparatus was present during protein body formation in a variety of cereals including wheat and that dense-cored Golgi vesicles were protease digestible. In addition, Bechtel Gaines and Pomeranz (1982) have identified protein bodies by enzymatic digestion with proteases.…”

Section: Introductionmentioning

confidence: 99%

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Early Stages in Wheat Endosperm Formation and Protein Body Initiation

1982

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The early stages of endosperm formation and protein body initiation are described for hard red winter wheat using light and transmission electron microscopy. Two days after flowering (DAF) the endosperm was a thin layer of coenocytic cytoplasm lining the embryo sac. By 4 DAF the endosperm had cellularized and completely filled the embryo sac. Enough differentiation had occurred by 6 DAF to distinguish cells destined to become the aleurone layer, sub-aleurone region and central endosperm. Protein bodies were initiated at about 6-7 DAF and were first found near the Golgi apparatus. Wheat was ready for combine harvest at 34 DAF. Enlargement of the small protein bodies near the Golgi apparatus occurred by several mechanisms: (1) fusion with one or more of the dense Golgi vesicles or fusion with other protein bodies, (2) fusion with small electron-lucent Golgi-deri ved vesicles, (3) pinocytosis of a portion of the adjacent cytoplasm into the developing protein body and (4) fusion of large protein bodies with one another at later stages of grain development. Of the four mechanisms described, the pinocytotic vesicles and fusion of protein bodies were the most frequent and consistent processes observed. Direct connections between rough endoplasmic reticulum (RER) and protein bodies were not observed. The results suggest a role for the Golgi apparatus in the initiation of protein bodies. Also, the lack of RER derived vesicles suggests a soluble mode of secretion of storage proteins involved in the enlargement of protein bodies.

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Section: Discussionmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 90%

Section: Protein Body Initiationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Early Stages in Wheat Endosperm Formation and Protein Body Initiation

1982

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“…DISCUSSION Protein digestion techniques have been employed for many years for determining the composition of cellular structures that have been prepared for electron microscopy. The validity of these techniques, however, has been questioned by many workers (Anderson & Andr6, 1968;Bechtel & Gaines, 1982;Behnke, 1975;Weintraub, Ragetli & Schroeder, 1971). Bechtel & Gaines (1982) listed several factors that may affect enzymic extraction of proteinaceous components, including: (1) exposing sections to the electron beam prior to extraction; (2) using osmium tetroxide as a fixative; and (3) using an embedding medium that penetrates the tissue so well that it prevents the enzyme from reaching the substrate.…”

Section: Nuclear Crystalloids In Sieve Elementsmentioning

confidence: 99%

Nuclear crystalloids in sieve elements of boraginaceae: A protein digestion study

Thorsch

Esau

1983

Journal of Cell Science

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Nuclear crystalloids have been found in sieve elements of several Boraginaceae. Nuclei of differentiating sieve elements of Echium and other genera except Amsinckia contain one or more crystalloids composed of thin rods densely packed in parallel arrangement. After the nuclei disintegrate in the maturing sieve element the crystalloids are released into the cell lumen where they persist intact. In Amsinckia the crystalloid consists of two components: a dense component, similar to the crystalloid in the other genera and a loosely arranged paracrystalline component. The proteinaceous nature of the nuclear crystalloids and their possible similarity to P-protein was investigated by enzyme digestion techniques. Three proteolytic enzymes were employed in this study: protease, pepsin and trypsin. Successful digestion of the dense crystalloid in both Echium and Amsinckia was obtained with each enzyme tested. P-protein plugging the sieve plate pores was also digested. The loose component in Amsinckia and the aggregated and dispersed P-protein were not affected by the enzyme digestion procedures. These results seemed to indicate that the density or compactness of the proteinaceous inclusions may play a role in the differential response.

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Development and Evaluation of a Freeze‐etch, Freeze‐fracture Technique Applied to Developing Wheat Endosperm

Bechtel¹,

Barnett²

1986

American J of Botany

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A technique was developed and evaluated whereby differentiating wheat endosperm tissue could be processed for the freeze‐etch, freeze‐fracture technique without the use of chemical fixatives. Field grown, developing hard red winter wheat (cv. Newton) caryopses were infiltrated with glycerol prior to freezing in liquid nitrogen‐cooled Freon‐22. Frozen samples were placed in cryogenic vials and stored in liquid nitrogen until needed. Freeze‐fracture was carried out under standard conditions. Evaluation of replicas from glycerol‐imbibed endosperm was made by comparing them to replicas obtained from freshly frozen untreated endosperm, and endosperm that had been prefixed in glutaraldehyde and paraformaldehyde. Other evaluations were made by comparing replicas of glycerol‐treated endosperm to thin sections obtained from wheat that had been imbibed with glycerol, fixed, dehydrated, and infiltrated and embedded in epoxy resin for routine electron microscopy. The results indicate that if the unfixed glycerol‐treated wheat endosperm is handled carefully, replicas can be obtained which show few artifacts due to glycerol and freezing. Typical artifacts such as vesiculation of RER, ice crystal damage, production of fusion intermediates, and membrane particle segregation can be nearly eliminated when this technique is applied to developing wheat endosperm.

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The Presence of Protease‐digestible Material in Golgi Vesicles During Endosperm Development of Selected Cereals

Cited by 6 publications

References 11 publications

Early Stages in Wheat Endosperm Formation and Protein Body Initiation

Early Stages in Wheat Endosperm Formation and Protein Body Initiation

Nuclear crystalloids in sieve elements of boraginaceae: A protein digestion study

Development and Evaluation of a Freeze‐etch, Freeze‐fracture Technique Applied to Developing Wheat Endosperm

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