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At least 55 records · Page 3Linked to original sources
PubMed1990

Ethanol-phosphotungstic acid and bismuth staining of spermatid nucleoli in mouse spermiogenesis.

The nucleoli of developing mouse spermatids were examined with ethanol-phosphotungstic acid (E-PTA) staining, and also with bismuth staining following formaldehyde fixation (FA-Bi staining) and glutaraldehyde fixation (GA-Bi staining). Only the cortical zone of the nucleolar dense fibrillar component (DFC) in the round spermatids was stained with E-PTA, while the inner area remained either faintly (early Golgi-phase spermatids) or completely unstained (cap-phase spermatids). Incubation of the fixed testis with dithiothreitol before E-PTA staining resulted in homogeneously intense staining of the DFC. The facts suggest that numerous E-PTA-positive basic proteins were present in the DFC, but disulfide crosslinks formed in the DFC proteins prevent penetration of PTA into the DFC interior. The DFC was stained with bismuth after FA-Bi and GA-Bi staining until the disappearance of the nucleoli occurring in acrosome-phase spermatids. The fibrillar center, homogeneously stained using E-PTA, FA-Bi, and GA-Bi methods was present in the nucleoli of Golgi-phase and early cap-phase spermatids, but disappeared in the nucleoli of late cap-phase spermatids. These results are discussed based on the previous studies dealing with the ribosomal RNA synthesis in mouse spermiogenesis.

Animals↗
PubMedDate not supplied

[Effect of the contrast conditions using solutions of phosphotungstic acid on the electron microscopic image of the foot-and-mouth disease virus].

A method of negative staining of foot-and-mouth disease virus preparations permits to obtain separately positive (2% phosphotungstic acid solution, pH 3.0) and negative (2% PTA solution, pH 6.8 +/- 8.0) stainings. When a 3--4% PTA solution, pH 6.8 +/- 8.0 is used, simultaneous positive and negative staining of each virion is possible which characterizes the functional heterogeneity of the virion protein membrane in interaction with PTA anions.

Aphthovirus↗
PubMed1976

Cytochemical studies on RNP complexes produced by puff 2-48BC in Drosophila hydei: uranyl acetate and phosphotungstic acid staining.

Differential staining of the core and RNP particles of RNP complexes in puff 2--48 BC in salivary gland chromosomes of Drosophila hydei was achieved with aqueous uranyl acetate (UA) at low pH, with UA in acetone, with phosphotungstic acid (PTA) in organic solvents, and with aqueous PTA at pH 5 And 6. A comparison of the results of UA and PTA staining under various conditions indicate that the proteins in the core region and in the RNP particles connected to it differ with respect to their amino-acid composition (arginine and lysine residues).--The staining mechanism of PTA and UA is discussed.

Acetates↗
PubMed1975

Ultrastructure of symmetric interneuronal junctions after staining with ethanolic phosphotungstic acid.

1. The symmetric interneuronal junctions (attachment plaques) of large axon terminals in the dorsal lateral geniculate body of the rat were studied, applying besides the conventional staining the block staining method with ethanolic phosphotungstic acid (E-PTA). 2. After staining these contact zones with E-PTA 3 main components become visible: the interior presynaptic layer, the intermembranous material and the postsynaptic layer. 3. As opposed to the asymmetric synaptic junctions the interior presynaptic layer is not divided into dense projections. 4. The intermembranous material consists of 2 median situated intracleft lines, which are more or less fused with each other. 5. The staining intensity of the paramembranous material of the symmetric junctions stained with E-PTA corresponds to the intensity of the material of the asymmetric synaptic junctions.

Animals↗
PubMed1993

Ultrastructure of phosphotungstic acid (PTA) positive deposits in the hippocampus of senile demented patients.

To perform a quantitative investigation on synaptic ultrastructural features in the human hippocampus in normal old and senile demented patients we stained our tissue samples by means of the ethanol-phosphotungstic acid (E-PTA) preferential technique. In addition to the synaptic contact zones, we found that structures similar to neurofibrillary tangles (NFT) and senile plaques (SP) were remarkably positive to our staining procedure, while the background was faintly electron lucent. On the basis of the E-PTA staining properties and specificity, we support that the reactive sites of these positive structures are represented by basic amino acids. The recently demonstrated presence of 4 basic amino acids (1 arginine, 3 histidine) in the cleaved fragment of the amyloid precursor protein (APP) suggest us to hypothesise that this APP portion may represent the common constitutive element of the many morphologically different alterations found in the brains of senile demented patients.

Aged↗
PubMed1976

A consistent phosphotungstic acid hematoxylin stain for glial fibers.

After deceration, celloidinization and hydration, oxidize 10 micron paraffin sections for 15 min in a solution containing 0.3 g KMnO4 and 0.1 ml conc. H2SO4 per 100 ml distilled water. Wash in water and reduce in 5% oxalic acid until the sections are colorless. Wash thoroughly in water and place in 4% iron alum solution for two hours. Wash briefly in water and stain for two hours in phosphotungstic acid hematoxylin. Rinse briefly in 95% ethanol and dehydrate in n-butyl alcohol or absolute ethanol for 4 min with two changes, clear and mount. Glial fibers, myofibrils, red blood cells, etc. are stained blue while astrocyte cell bodies, collagen, etc. are stained red. This stain has proven highly consistent in a wide variety of astrocytic derangements. Despite the intensity of this PTAH modification, false positive staining was not observed.

Astrocytes↗
PubMed1994

Sequential treatment by phosphotungstic acid and uranyl acetate enhances the adherence of lipid membranes and membrane proteins to hydrophobic EM grids.

A simple procedure for screening by electron microscopic observations of conditions for the reconstitution of membrane proteins into lipid bilayers is described. This procedure consists of a 5-10 s treatment of electron microscopic grids, to which the sample has already been applied, with 1% phosphotungstic acid before proceeding with final staining in uranyl acetate. The method substantially enhances the adherence of lipid membranes and membrane protein particles to hydrophobic collodion/carbon grids.

Adhesiveness↗
PubMed1981

Selective staining of dictyosome-like structures (DLS) from spermatocytes of the guinea pig using phosphotungstic acid at low pH.

Dictyosome-like structures (DLS) occur abundantly in primary spermatocytes of the guinea pig. DLS superficially resemble dictyosomes of Golgi apparatus in that they consist of stacked cisternae and react similarly to some cytochemical markers. DLS saccules are also present in residual bodies and in the cytoplasmic droplet of the sperm, but the stacked configuration (or dictyosome form) is seldom present at these stages of development. A mixture of 1% phosphotungstic acid in 10% chromic acid selectively stains the DLS and DLS saccules of guinea pig germ cells. The thick cisternae of spermatid Golgi apparatus and the sperm plasma membrane also stain, but endoplasmic reticulum and the parts of the Golgi apparatus other than the thick cisternae do not stain. The specificity of the stain is retained in crude homogenates as well as in purified cell fractions and may be helpful in identification of DLS in cell fractionation studies. Additionally, the information obtained provides clues to the origin and fate of DLS in the developing mammalian germ cells.

Animals↗
PubMed1984

Observations on the kinetics of uranyl acetate and phosphotungstic acid staining of chromatin in thin sections for electron microscopy.

When thin sections of spermatogenic chromatin are fixed with either glutaraldehyde alone or postfixed with osmium tetroxide (OsO4) and stained with uranyl acetate (UAc) for increasing times, even after as little as 1 min, stain uptake is proportional to section thickness. Greater UAc uptake is observed in chromatin fixed with glutaraldehyde only, but seen with postfixed chromatin. Lead citrate poststaining of chromatin fixed with either glutaraldehyde or postfixed with OsO4 increases UAc uptake by a factor of about 3. The staining of thin sections of spermatogenic chromatin with ethanolic phosphotungstic acid (PTA) shows a region where stain uptake is proportional to section thickness followed by a plateau. This staining pattern is seen in chromatin fixed with glutaraldehyde alone or postfixed with OsO4; similar levels for final PTA uptake are also observed. An increase in the resin content of embedded chromatin postfixed with OsO4 is proposed to explain the decrease and increase in the rate of migration of UAc and ethanolic PTA staining solutions, respectively.

Animals↗
PubMed2005

Anhydrous and water-assisted proton mobility in phosphotungstic acid.

Nonlocal gradient-corrected density functional theoretical calculations were used to determine the energetics associated with proton migration in phosphotungstic acid. The activation energy for anhydrous proton hopping between two oxygen atoms on the exterior of the molecular Keggin unit was calculated to be 103.3 kJ mol(-1). The quantum-tunneling effect on the rate of proton movement was determined using semiclassical transition-state theory and was found to be a major contributor to the overall rate of proton movement at temperatures below approximately 350 K. The adsorption of water on an acidic proton decreases the activation barrier for hopping to 11.2 kJ mol(-1) by facilitating proton transfer along hydrogen bonds. The overall rate constant for proton hopping was determined as a function of temperature and water partial pressure. Small amounts of water greatly enhance the overall rate of proton movement.

Journal Article↗
PubMed2005

Addition of phosphotungstic acid to ethanol for dehydration improves both the ultrastructure and antigenicity of pituitary tissue embedded in LR White acrylic resin.

Although hydrophilic acrylic resins including LR White have been widely utilized as embedding media for immunocytochemical use, the constituents of tissues are often extracted by the resin monomer during the infiltration process of the embedment, resulting in a discernible impairment of the ultrastructure when the tissue is weakly fixed only with aldehydes. To minimize the extraction by the resin monomer, the embedding procedure with LR White resin was reexamined in the present study. Among the treatments tested, a partial dehydration with 70% ethanol containing 2% phosphotungstic acid (PTA) well preserved the ultrastructure of the pituitary tissue without spoiling the antigenicity of LHbeta and other representative markers for the Golgi apparatus. In addition, treatment with 1% tannic acid (TA) prior to the dehydration described above synergistically improved both the ultrastructure and antigenicity of the tissue so that the orientation of the Golgi apparatus could be determined by double immunogold labeling with commercially available anti-GM130 and anti-TGN38 antibodies. The ultrathin sections from the LR White-embedded tissue treated with TA and dehydrated in 70% ethanol containing 2% PTA also enhanced contrast without conventional heavy-metal staining with uranyl acetate and lead citrate. Our findings further suggest that the precipitation of TA and PTA protected the tissue from being extracted during the embedment, probably because an insoluble complex was transiently formed with the constituents of the tissue. This simple modification of the LR White embedment can extend the application of post-embedding immunocytochemistry as an alternative to pre-embedding immunolabeling with frozen ultrathin sections.

Acrylic Resins↗