Tissue fixation and staining with osmium tetroxide: the role of phenolic compounds.

1978 ◽  
Vol 26 (2) ◽  
pp. 138-140 ◽  
Author(s):  
A J Nielson ◽  
W P Griffith
Keyword(s):  
Phenolic Compounds ◽  
Electron Density ◽  
Normal Tissue ◽  
Osmium Tetroxide ◽  
Direct Interaction ◽  
Plant Tissues ◽  
Tissue Fixation ◽  
Chelate Complexes ◽  
Animal Tissues

It has been postulated that phenol-containing areas of plant and animal tissues were osmiophilic, but proof of direct interaction between osmium tetroxide and phenolic materials, or the nature of such reactions, has been lacking. We find that, under conditions similar to those of normal tissue fixation, osmium tetroxide reacts rapidly with those phenols containing o-dihydroxy groups (including such species found in plant tissues) to give very stable chelate complexes. We conclude that these complexes are responsible for the observed electron-density in phenol-containing areas of tissue treated with osmium tetroxide, so that such phenols are indeed osmiophilic.

scholarly journals Tissue fixation by osmium tetroxide. A possible role for proteins.

1979 ◽  
Vol 27 (5) ◽  
pp. 997-999 ◽  
Author(s):  
A J Nielson ◽  
W P Griffith
Keyword(s):  
Normal Tissue ◽  
Osmium Tetroxide ◽  
Chemical Nature ◽  
Side Chain ◽  
Cross Linking ◽  
Tissue Fixation ◽  
Reaction Products ◽  
Cholesteryl Acetate ◽  
Unsaturated Lipids

The osmiophilia, under the conditions of normal tissue fixation, of the histidine, lysine, tryptophan, cysteine and methionine side chain of proteins is suggested by in vitro studies on blocked amino acids representative of such protein side chains, and the chemical nature of the reaction products elucidated. The chemical feasibility of inter- or intramolecular cross-linking of protein by OsO4 at these and other sites is demonstrated, as in the cross-linking of protein with unsaturated lipids such as methyl oleate, methyl linoleate and linolenate, and cholesteryl acetate. The relevance of these results to the process of tissue fixation by OsO4 is discussed.

scholarly journals Tissue fixation and staining by osmium tetraoxide: a possible role for alkaloids.

1981 ◽  
Vol 29 (11) ◽  
pp. 1347-1348 ◽  
Author(s):  
M J Wright ◽  
M Schröder ◽  
A J Nielson
Keyword(s):  
Normal Tissue ◽  
In Vitro Studies ◽  
Plant Tissues ◽  
Tissue Fixation ◽  
Osmium Tetraoxide

In vitro studies on the reactions of osmium tetraoxide, OsO4, with isoquinoline, pyridine, quinuclidine, and a series of structurally related alkaloids suggest that these species, under the conditions of normal tissue staining and fixation, are potentially osmiophilic. The structure of the products and their reactions with unsaturated substrates are described. The relevance of these results to the process of tissue staining and fixation of plant tissues containing alkaloids by OsO4 is discussed.

Dolichol: a curriculum cognitionis

1992 ◽  
Vol 70 (6) ◽  
pp. 377-381 ◽  
Author(s):  
Frank W. Hemming
Keyword(s):  
Biosynthetic Pathway ◽  
Side Chain ◽  
Plant Tissues ◽  
Animal Tissues ◽  
Dolichyl Phosphate ◽  
Putative Precursor ◽  
Eukaryotic Organisms ◽  
Derivatives Of ◽  
Long Chain

Dolichols were first described about 30 years ago when animal tissues were being examined for the presence of a putative precursor to the polyisoprenoid side chain of ubiquinone. These long-chain 2,3-dihydro-polycis-isoprenoid alcohols are found in all eukaryotic organisms. In many plant tissues they are accompanied by families of other polyisoprenoid alcohols that are usually similar molecules and possess an unsaturated α-isoprene residue. Analogy with the role of bactoprenyl phosphates in the synthesis of bacterial wall glycans led to the discovery that the mono- and di-phosphates of dolichols function as cofactors in protein N-glycosylation, involving the formation of glycosylated derivatives of dolichol as intermediates. Variation of the concentration of dolichyl phosphate was shown to be one way of controlling protein N-glycosylation. This can be achieved by modification of the relative activities of dolichol kinase and dolichol phosphate phosphatase. Modulation of the biosynthetic pathway, still not fully understood, of dolichyl phosphate may also be an important factor. Several disease conditions involve aberrations in these pathways.Key words: dolichols, polyisoprenoid alcohols, N-glycosylation, O-mannosylation.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

Application of ruthenium red/osmium tetroxide to bacteria, plant and animal tissue

1986 ◽  
Vol 44 ◽  
pp. 54-55
Author(s):  
R. L. Grayson ◽  
N. A. Rechcigl
Keyword(s):  
Electron Microscopy ◽  
Electron Density ◽  
Osmium Tetroxide ◽  
Biological Materials ◽  
Ruthenium Red ◽  
Animal Tissue

Ruthenium red (RR), an inorganic dye was found to be useful in electron microscopy where it can combine with osmium tetroxide (OsO4) to form a complex with attraction toward anionic substances. Although Martinez-Palomo et al. (1969) were one of the first investigators to use RR together with OsO4, our computor search has shown few applications of this combination in the intervening years. The purpose of this paper is to report the results of our investigations utilizing the RR/OsO4 combination to add electron density to various biological materials. The possible mechanisms by which this may come about has been well reviewed by previous investigators (1,3a,3b,4).

scholarly journals Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Vanessa Loaiza-Cano ◽  
Laura Milena Monsalve-Escudero ◽  
Carlos da Silva Maia Bezerra Filho ◽  
Marlen Martinez-Gutierrez ◽  
Damião Pergentino de Sousa
Keyword(s):  
Phenolic Compounds ◽  
Dengue Virus ◽  
Biological Activities ◽  
Antiviral Effect ◽  
Health Concern ◽  
Host Proteins ◽  
Viral Particles ◽  
Antiviral Role ◽  
Productive Replication

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

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