scholarly journals LOCALIZATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN THE RAT SPERM TAIL AS REVEALED BY ELECTRON MICROSCOPY

1965 ◽  
Vol 25 (2) ◽  
pp. 101-112 ◽  
Author(s):  
Toshio Nagano
Keyword(s):  
Osmium Tetroxide ◽  
Surface Membrane ◽  
Nitrate Solution ◽  
Lead Nitrate ◽  
Reaction Products ◽  
Lead Phosphate ◽  
Sperm Tail ◽  
Middle Piece ◽  
The Matrix ◽  
Coarse Fibers

The epididymides of rat testis were fixed in glutaraldehyde and cut as frozen sections. The sections were incubated in lead nitrate solution containing as a substrate either ATP, AMP, creatinine phosphate, beta glycerophosphate, or phenyl phosphate. Then they were postfixed in osmium tetroxide, embedded, sectioned, and examined with the electron microscope. In the sperm tail, when ATP is used as a substrate the reaction product (lead phosphate) is observed both in the tail filament complex and on the surface membrane of the mitochondrial helix of the middle piece. In the tail filament complex, this product is seen near the nine paired peripheral and two central filaments, and in the matrix between the outer coarse fibers. But the product is not observed within these filaments and fibers. In longitudinal sections, no periodicity of the deposits in the complex is observed. When the other phosphate compounds are used as substrates the reaction products appear on the surface membrane of the mitochondrial helix, and are not found in the tail filament complex. No distinctly different localization of the reaction products is observed when substrates other than ATP are used. Possible relationships between the structure and the function of the sperm tail are discussed in the light of these findings.

scholarly journals CYTODIFFERENTIATION DURING SPERMIOGENESIS IN LUMBRICUS TERRESTRIS

1967 ◽  
Vol 32 (1) ◽  
pp. 11-26 ◽  
Author(s):  
W. A. Anderson ◽  
A. Weissman ◽  
R. A. Ellis
Keyword(s):  
Endoplasmic Reticulum ◽  
Outer Membrane ◽  
Osmium Tetroxide ◽  
Structural Changes ◽  
Lumbricus Terrestris ◽  
Posterior Pole ◽  
Seminal Vesicles ◽  
Sperm Tail ◽  
Middle Piece ◽  
Spermatid Nucleus

The structural changes during spermiogenesis were studied on developing spermatids in seminal vesicles and receptacles of Lumbricus terrestris fixed in glutaraldehyde-osmium tetroxide and embedded in Epon-Araldite. The centriole plays a prominent role in the morphogenesis and organization of the microtubules of the manchette and flagellum. Microtubules arising from the centriole extend anteriorly to encase the developing middle piece, the nucleus, and the acrosome. The manchette not only provides a supporting framework for the cell during elongation, but also may provide the motive force for the elimination of both nucleoplasm and cytoplasm. The manchette participates in segregation and elimination of the nuclear vesicle that contains the nonchromatin nucleoplasm. Compartmentalization and conservation may also be a function of the manchette since those elements which remain within the framework of microtubules are retained, while all the cytoplasm outside the manchette is discarded. At maturation, the endoplasmic reticulum plays a key role in dismantling the manchette and reducing the cytoplasm external to it. During the early stages of middle-piece formation, six ovoid mitochondria aggregate at the posterior pole of the spermatid nucleus. Concurrent with manchette formation, the mitochondria are compressed laterally into elongate wedge-shaped components, and their outer limiting membranes fuse to form an hexagonal framework that surrounds the dense intramitochondrial matrices. Dense glycogen granules are arranged linearly between the peripheral flagellar tubules and the outer membrane of the mature sperm tail.

The Distribution of the Protein-Polysaccharide Complex in the Nucleus Pulposus Matrix in Young Rabbits

1968 ◽  
Vol 3 (1) ◽  
pp. 33-40
Author(s):  
J. W. SMITH ◽  
A. SERAFINI-FRACASSINI
Keyword(s):  
Nucleus Pulposus ◽  
Osmium Tetroxide ◽  
Lead Nitrate ◽  
Vitreous Body ◽  
Collagen Fibrils ◽  
Bismuth Nitrate ◽  
Young Rabbit ◽  
Native Collagen ◽  
The Matrix ◽  
Concentrated Solution

The distribution and relationship of the collagen and the proteinpolysaccharide complex in the extracellular matrix of the nucleus pulposus of the young rabbit were studied by electron microscopy. The polysaccharide was demonstrated by treatment of the tissue with either 0.5% bismuth nitrate at pH 2 or a mixture of equal volumes of 1% lead nitrate and 2% osmium tetroxide at pH 5. The protein part of the complex was observed in tissue fixed in osmium tetroxide at pH 7.2 and stained with 1% phosphotungstic acid. The collagen of the tissue was apparent in all preparations. The water-extracted proteinpolysaccharide was studied after coagulation of a concentrated solution in 0.5% bismuth nitrate, whereas the isolated fibrous fraction was examined by negative staining of sprayed material. Collagen is present in the intact tissues as native collagen fibrils of about 300 Å diameter, and as sheets, 4OO-Å thick, of parallel, separate, filaments of 50-60 Å diameter. Usually several such sheets lie close, and approximately parallel, to one another. After extraction of the proteinpolysaccharide from the tissue with water, all the collagenous components tend to aggregate into large native collagen fibrils. Some of the proteinpolysaccharide complex of the intact tissue is free in the matrix. The polysaccharide moiety is visualized as 270 Å particles, serially attached to a protein core in the form of beaded filaments about 40Å in diameter. The rest of the complex is attached to the sheets of collagen filaments in regular periodic zones which are 270 Å wide and centred 670 Å apart. None of the complex appears to be associated with the larger collagen fibrils. The staining reactions of the polysaccharides in several connective tissues are discussed and the relationships of the proteinpolysaccharide complexes to collagen in cartilage, the vitreous body and the nucleus pulposus are compared.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Mitochondria: the birth place, battle ground and the site of melatonin metabolism in cells

2019 ◽  
Vol 2 (1) ◽  
pp. 44-66 ◽  
Author(s):  
Dun-Xian Tan ◽  
Russel. J. Reiter
Keyword(s):  
Ischemia Reperfusion ◽  
Surface Membrane ◽  
Strong Association ◽  
Membrane Receptors ◽  
Melatonin Receptors ◽  
Metabolic Enzyme ◽  
Intermembrane Space ◽  
Antitumor Effects ◽  
The Matrix ◽  
Surprising Discovery

     It was a surprising discovery when mitochondria, as the power houses of cells, were also found to synthesize the potent mitochondrial targeted antioxidant, melatonin. The melatonin synthetic enzyme serotonin N-acetyltransferase (SNAT) was found in matrix and also in the intermembrane space of mitochondria. We hypothesize that the melatonin synthesis occurs in the matrix due to substrate (N-acetyl co-enzyme A) availability while the intermembrane space may serve as the recycling pool of SNAT to regulate the melatonin circadian rhythm. Another surprise was that the melatonin membrane receptors, including MT1 and MT2, were also present in mitochondria. The protective effects of melatonin against neuronal injury induced by brain ischemia/reperfusion were proven to be mainly mediated by mitochondrial melatonin receptors rather than the cell surface membrane receptors which is contrary to the classical principle. In addition, melatonin metabolic enzyme has also been identified in the mitochondria. This enzyme can convert melatonin to N-acetylserotonin to strengthen the antitumor effects of melatonin. Thus, mitochondria are the generator, battle ground and metabolic sites of melatonin. The biological significance of the strong association between mitochondria and melatonin should be intensively investigated. 

Mitochondria: the birth place, battle ground and the site of melatonin metabolism in cells

2019 ◽  
Vol 2 (1) ◽  
pp. 44-66 ◽  
Author(s):  
Dun-Xian Tan ◽  
Russel. J. Reiter
Keyword(s):  
Ischemia Reperfusion ◽  
Surface Membrane ◽  
Strong Association ◽  
Membrane Receptors ◽  
Melatonin Receptors ◽  
Metabolic Enzyme ◽  
Intermembrane Space ◽  
Antitumor Effects ◽  
The Matrix ◽  
Surprising Discovery

     It was a surprising discovery when mitochondria, as the power houses of cells, were also found to synthesize the potent mitochondrial targeted antioxidant, melatonin. The melatonin synthetic enzyme serotonin N-acetyltransferase (SNAT) was found in matrix and also in the intermembrane space of mitochondria. We hypothesize that the melatonin synthesis occurs in the matrix due to substrate (N-acetyl co-enzyme A) availability while the intermembrane space may serve as the recycling pool of SNAT to regulate the melatonin circadian rhythm. Another surprise was that the melatonin membrane receptors, including MT1 and MT2, were also present in mitochondria. The protective effects of melatonin against neuronal injury induced by brain ischemia/reperfusion were proven to be mainly mediated by mitochondrial melatonin receptors rather than the cell surface membrane receptors which is contrary to the classical principle. In addition, melatonin metabolic enzyme has also been identified in the mitochondria. This enzyme can convert melatonin to N-acetylserotonin to strengthen the antitumor effects of melatonin. Thus, mitochondria are the generator, battle ground and metabolic sites of melatonin. The biological significance of the strong association between mitochondria and melatonin should be intensively investigated. 

The Reactivity of CaTi4(PO4)6 with Alumina and Y-TZP Ceramics

2007 ◽  
Vol 361-363 ◽  
pp. 787-790
Author(s):  
Sabina Beranič Klopčič ◽  
Irena Pribošič ◽  
Tomaž Kosmač ◽  
Ute Ploska ◽  
Georg Berger
Keyword(s):  
Room Temperature ◽  
Xrd Analysis ◽  
Second Phase ◽  
Reaction Products ◽  
Stabilized Zirconia ◽  
Monoclinic Zro2 ◽  
Commercial Alumina ◽  
The Matrix ◽  
Different Temperatures ◽  
Edx Analyses

The reactivity of CaTi4(PO4)6 (CTP) with alumina and yttria-stabilized zirconia (Y-TZP) ceramics was studied. CTP powder was synthesized and composites with commercial alumina or zirconia matrices containing 10 wt% of CTP were prepared. They were sintered at different temperatures and characterized using XRD, SEM, and EDX analyses. The results showed that the alumina/CTP and Y-TZP/CTP composites start to react below 1000 °C. In the alumina/CTP composite the first reaction product, detected at 970 °C, was AlPO4. At temperatures above 1280 °C TiO2 and CaTiO3 were also formed and no CTP peaks could be detected using XRD analysis. The composite sintered at 1500 °C consisted of Al2O3 matrix, AlPO4, TiO2, CaTiO3 and Al2TiO5. The reaction products formed in the Y-TZP/CTP composite at 970 °C were TiO2 and Ca2Zr7O16. At higher sintering temperatures, 1280 °C and above, CTP was no longer present, Ca2Zr7O16 decomposed, forming CaO2 and ZrO2, and Y2O3 was consumed to form YPO4. Consequently, upon cooling to room temperature the matrix phase transformed to monoclinic ZrO2. Based on these results it can be concluded that CTP is not a suitable bioactive second phase for the fabrication of CTP composites with alumina or zirconia matrices.

scholarly journals A detection method for lactic dehydrogenase activity in the inner ear.

1978 ◽  
Vol 26 (4) ◽  
pp. 313-317 ◽  
Author(s):  
T Omata ◽  
I Ohtani ◽  
K Ohtsuki ◽  
J Ouchi
Keyword(s):  
Hair Cells ◽  
Osmium Tetroxide ◽  
Light And Electron Microscopy ◽  
Organ Of Corti ◽  
Lactic Dehydrogenase ◽  
Outer Hair Cells ◽  
Water Soluble ◽  
Reaction Products ◽  
Frozen Sections ◽  
Membranous Labyrinth

A method for the detection of lactic dehydrogenase enzymatic activity in outer hair cells of the rabbit is described. The membranous labyrinth with temporal bone was prefixed in glutaraldehyde. After being placed into the incubation medium, it was postfixed in osmium tetroxide. Specimens of the organ of Corti were removed. Then the specimens were embedded in water-soluble glycol and cut with a cryostat for light microscopy, and also they were embedded in Epon and cut for light and electron microscopy. Sectioning of the membranous labyrinth was very easily made when the specimens were embedded in both the water-soluble glycol and the Epon. The structures of the frozen sections as well as the Epon-embedded ones were well preserved. In the frozen sections the preservation and localization of reaction products were thoroughly kept, but monoformazan of the Epon-embedded sections was soluble.

Influence of Manganese Ions on the Electrodeposition Process of Lead Dioxide in Lead Nitrate Solution

2019 ◽  
Vol 55 (5) ◽  
pp. 364-369
Author(s):  
Yingwu Yao ◽  
Chunjiao Huang ◽  
Haishu Dong ◽  
Feng Wei ◽  
Xin Chen
Keyword(s):  
Lead Dioxide ◽  
Nitrate Solution ◽  
Lead Nitrate ◽  
Manganese Ions ◽  
Electrodeposition Process

scholarly journals STUDIES ON CARTILAGE

1960 ◽  
Vol 8 (1) ◽  
pp. 151-163 ◽  
Author(s):  
Huntington Sheldon ◽  
Robert A. Robinson
Keyword(s):  
Amorphous Material ◽  
Surface Membrane ◽  
Electrophoretic Pattern ◽  
Elastic Component ◽  
Elastic Tissue ◽  
Cell Cytoplasm ◽  
Elastic Cartilage ◽  
Rabbit Ear ◽  
The Matrix ◽  
Ear Cartilage

Electron microscope observations on rabbit ear cartilage following the administration of papain show that both the elastic component of the matrix and the amorphous material disappear leaving a matrix which consists of delicate fibrils which are presumed to be collagen. This unmasking of fibrils coincides with the appearance of an abnormal component in the electrophoretic pattern of the rabbit's serum. The chondrocytes show vacuoles in their cytoplasm which appear at the same time that the cells appear crenated in the light microscope. A ruffly appearance of the cell surface membrane coincides with this vacuolization, and vacuoles often appear open and in continuity with the extracellular space. The resurgence of the rabbit ear is accompanied by a reconstitution of both the amorphous material and the elastic component of the matrix. During this period numerous dilated cisternae of the endoplasmic reticulum which contain a moderately dense material are present in the chondrocyte cytoplasm. We have been unable to demonstrate a direct relationship between the elastic component of the matrix and a particular component of the chondrocyte cytoplasm, but it is clear that changes occur in the cartilage cell cytoplasm during both the depletion and reconstitution of the matrix. Previous studies on the effect of papain on elastic tissue are noted and the possible relationships between changes in the cells and matrix of this elastic cartilage are discussed.

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