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Biomedical subjects

E L Vigil

Publications and source records attributed to E L Vigil.

15 recordsLinked to original sources
PubMed1985

Development and enzyme activity of protein bodies in proteinoplasts of tobacco root cells.

The development of protein bodies in proteinoplasts of tobacco (Nicotiana tabacum L. var. Wis. 38) roots was investigated with TEM, HVEM, and enzyme cytochemistry. These plastids contain a three-dimensional network of fenestrated tubules which originate from invaginations of the inner membrane of the plastid envelope. Elaboration of the network occurs in parallel with cell differentiation: slender tubules common to plastids in meristematic cells undergo dilation as protein accumulates during cell differentiation; proteinoplasts of vacuolate and root cap cells usually contain a large protein body. The contents of the peripheral tubules, originating from the inner membrane, are less electron dense than the tubules making up the central network. Localized dilations within the tubular network result in the formation of dense spheroidal structures, protein bodies, apparently as a result of continued protein accumulation via tubules connecting to the central network. Protein might be imported from segments of rough ER attached to or apposed to the outer membrane of the proteinoplast envelope. The presence of catalase (E.C. 1.11.1.6), peroxidase (E.C. 1.11.1.7), and cytochrome oxidase (E.C. 1.9.3.1) was demonstrated by cytochemistry with diaminobenzidine (DAB) as substrate. Oxidized DAB was found in protein bodies after incubation in each of the specific reaction media. While aminotriazole and sodium azide inhibited oxidation of DAB by catalase and peroxidase, respectively, only potassium cyanide completely inhibited oxidation of DAB in protein bodies. We conclude that protein bodies of proteinoplasts in tobacco roots are not sites for storage of protein, rather protein bodies contain heme protein(s) with strong oxidase activity that may convey a specific function to proteinoplasts.

Enzymes↗
PubMed1979

Myoglobin as an ultrastructural probe for studying permeability of the nephron.

Hemeproteins, like cytochrome c (12,500 M.W.; Karnovsky and Rice, 1969) and myoglobin (17,816 M.W.; Anderson, 1972; Simionescu et al., 1973) are advantageous over the true peroxidases with larger molecular weights (e.g. horseradish peroxidase, ca. 40,000 M.W) as ultrastructural probes in that they do not elicit vascular leakage in the inflammatory response (Cotran and Karnovsky, 1967) and are relatively nontoxic immunologically inert substances. The main disadvantage in using cytochrome c and myoglobin is that they have weak peroxidatic activity compared to the true peroxidases (Nakamura et al., 1960; Keilin, 1961; Kurozimi et al., 1961). These hemeproteins, however, offer the following advantages: 1) they retain sufficient peroxidatic activity after aldehyde-fixation to oxidize 3,3'-diaminobenzidine (DAB), 2) they may be localized by virtue of an insoluble reaction product (osmium black) deposited at the site of hemeprotein immobilization by fixation, and 3) they represent low molecular weight probes. This brief report emphasizes the advantages of myoglobin in the study of glomerular permeability, transport by endocytosis in proximal tubules and translocation of protein in the lower segments of the nephron.

Animals↗
PubMed1978

Cytochemical demonstration of glutaraldehyde-resistant NADH-ferricyanide oxido-reductase activities in rat-liver plasma membranes and Golgi apparatus.

NADH-ferricyanide reductase activity was demonstrated in rat liver endomembranes by cytochemical procedures. The activity observed in plasma membrane and mature portions of the Golgi apparatus resisted fixation in 0.1% glutaraldehyde, a characteristic which permitted differentiation of the NADH-ferricyanide reductase of plasma membranes and mature Golgi apparatus elements from those of mitochondria, microbodies, endoplasmic reticulum and nuclear envelope. With the latter membranes, activity could be demonstrated only with unfixed material or following brief glutaraldehyde fixation and was greatest with broken cells or isolated fractions due to problems of penetration of reagents. Biochemical studies paralleled cytochemical findings with respect to glutaraldehyde fixation and sensitivity to other metabolic inhibitors. The findings provide evidence that a NADH-ferricyanide reductase may be among the membrane constituents conserved and/or modified during flow differentiation of membranes. The basis for a method to evaluate plasma membrane contamination of endoplasmic reticulum fractions and to differentiate among mature and immature secretory vesicles of the Golgi apparatus is also indicated.

Animals↗
PubMed1975

Peroxisome development in the metanephric kidney of mouse.

The relationship of enzymatic activity to organelle development and organelle number during differentiation of the metanephric kidney in the mouse was approached from several experimental directions. Biochemical analyses of marker enzymes for peroxisomes (catalase and D-amino acid oxidase), mitochondria (cytochrome oxidase) and lysosomes (acid phosphatase) were performed on kidneys at ages from 17 days prenatal to adult. These data were correlated with a morphometric analysis of populations of peroxisomes and mitochondria in differentiating cells of the proximal tubule. Postnatal development of the metanephric kidney was found to be accompanied by a rapid increase in both the specific activity of catalase and the number of peroxisomes per 100 mu2 in the proximal tubule during the first 4 weeks of postnatal growth. Elaboration of the endoplasmic reticulum (ER) was seen to parallel the increase in number of peroxisomes to which segments of ER were often in close apposition. Extensive interactions between segments of ER and peroxisomes were readily visible in 0.5-mu sections viewed in the high voltage electron microscope. In contrast to peroxisomes, neither mitochondria nor lysosomes followed a similar pattern of net organelle increase, suggesting that a defined population density of mitochondria and lysosomes may exist in the proximal tubule at birth, prior to complete development of the kidney.

Acid Phosphatase↗
PubMed1973

Effect of gibberellic Acid and actinomycin d on the formation and distribution of rough endoplasmic reticulum in barley aleurone cells.

Analysis of structural changes in barley aleurone cells during germination or following incubation of isolated layers in gibberellic acid with or without actinomycin D revealed extensive development of rough endoplasmic reticulum. Following the assembly of stacked rough endoplasmic reticulum, vesiculation occurred mainly in basal regions of the cell, resulting in a polar distribution of rough endoplasmic reticulum vesicles. It is postulated that these vesicles are involved in protein secretion, because smooth vesicles, derived from the rough endoplasmic reticulum, apparently become appressed to the plasma membrane. The increased alpha-amylase in the ambient medium and in cell homogenates correlated directly with formation and subsequent vesiculation of the rough endoplasmic reticulum. Furthermore, when cells were treated with actinomycin D and gibberellic acid, alpha-amylase synthesis was inhibited by 45% and secretion by 63%. These cells were characterized cytologically by large areas of disarrayed segments of fragmented rough endoplasmic reticulum, corresponding to a high intracellular level of alpha-amylase. In addition, small lipid bodies common to the segmented regions of rough endoplasmic reticulum were surrounded by fine fibrous material, short segments of rough endoplasmic reticulum, and free ribosomes, suggesting that actinomycin D had interfered with development and organization of rough endoplasmic reticulum.

Journal Article↗
PubMed1970

Cytochemical and developmental changes in microbodies (glyoxysomes) and related organelles of castor bean endosperm.

Structural changes in endosperm cells of germinating castor beans were examined and complemented with a cytochemical analysis of staining with diaminobenzidine (DAB). Deposition of oxidized DAB occurred only in microbodies due to the presence of catalase, and in cell walls associated with peroxidase activity. Seedling development paralleled the disappearance of spherosomes (lipid bodies) and matrix of aleurone grains in endosperm cells. 6 to 7 days after germination, a cross-section through the endosperm contained cells in all stages of development and senescence beginning at the seed coat and progressing inward to the cotyledons. Part of this aging process involved vacuole formation by fusion of aleurone grain membranes. This coincided with an increase in microbodies (glyoxsomes), mitochondria, plastids with an elaborate tubular network, and the formation of a new protein body referred to as a dilated cisterna, which is structurally and biochemically distinct from microbodies although both apparently develop from rough endoplasmic reticulum (ER). In vacuolate cells microbodies are the most numerous organelle and are intimately associated with spherosomes and dilated cisternae. This phenomenon is discussed in relation to the biochemical activities of these organelles. Turnover of microbodies involves sequestration into autophagic vacuoles as intact organelles which still retain catalase activity. Crystalloids present in microbodies develop by condensation of matrix protein and are the principal site of catalase formerly in the matrix.

Catalase↗