Life Sciences Commons^™

Urinary Stone Proteins: An Update, J. P. Binette, M. B. Binette, M. A. Gawinowicz, N. Kendrick

Scanning Microscopy

The discovery of an organic component in kidney stones dates back to 1684. More than 150 years elapsed before the incrustation of this organic component, which is now called the matrix, was proposed as the mechanism of stone formation. The composition of the matrix remained largely unknown until the development of electron microscopy and the advances in biochemistry combined in the 1950's to usher in the modern era of renal stone matrix investigation. Composed mainly of selectively incorporated proteins generally characterized by high glutamic and aspartic acid content and the frequent occurrence of y-carboxyglutamic acid, the matrix dis-plays a variable …

Adsorption Of Fibrinogen On Thin Oriented Poly(Tetrafluoroethylene) (Ptfe) Fibres Studied By Scanning Force Microscopy, J. R. Rasmusson, R. Erlandsson, W. R. Salaneck, M. Schott, D. T. Clark, I. Lundström

Scanning Microscopy

We have investigated fibrinogen adsorption on ordered poly(tetrafluoroethylene), PTFE, fibres deposited on hydrophilic and hydrophobic silicon substrates. Fibrinogen molecules appear to adsorb with their long axis perpendicular to the fibre direction for PTFE fibres having widths of less than 100 nm. On these thin fibres, fibrinogen apparently forms close packed bands or clusters, consisting of small integer numbers of molecules arranged parallel to each other. On broader (> 100 nm) PTFE fibres, the fibrinogen forms two dimensional networks. The orientation of the molecules in these networks is random in the central flat part of the fibres but perpendicular to the …

Sequencing Of Proteins Extracted From Stones, J. P. Binette, M. B. Binette

Scanning Microscopy

Proteins from urinary tract and gallbladder stones were extracted and characterized to determine the composition of the matrix and possibly unravel the role of the organic phase in stone formation. Proteins from crushed stones were extracted by electrodialysis and concentrated in the Amicon centricon cartridge or by lyophilization after dialysis against distilled water. Aliquots were first analyzed by isoelectric focusing in gel and if suitable subjected to two-dimensional (2D) electrophoresis. The most promising spots were harvested and the N-terminal amino acids sequenced, thus providing maximum information with minimum expenditure of material. The 2D separations and amino acid sequences of several …

A Cationic Protein From A Urate-Calcium Oxalate Stone: Isolation And Purification Of A Shared Protein, J. P. Binette, M. B. Binette

Scanning Microscopy

A protein extracted from a urate - calcium oxalate stone by electrodialysis is also excreted in the urine which served as the source material for its purification by FPLC after separation on an ACA44 column. It has an amino acid composition appropriate for a cationic protein. One peptide obtained by cyanogen bromide cleavage has significant (approximately 60%) homology with CD59 protein (protectin). Both proteins have wide distribution, the unknown having been found in bile, cholesterol gallstones, and the wall of the aorta. However, the two proteins appear to be immunologically different.

The Stabilisation Of Air In Foods Containing Fat - A Review, B. E. Brooker

Food Structure

Foods containing aqueous solutions of proteins readily foam when air is introduced into them. When fat is also present, interaction between the two components at the air/water interface may produce a stable foam with characteristic bulk properties. In the case of dairy foams (such as whipped cream), bubbles produced in the whipping process are initially stabilised by the adsorption of protein at the air/water interfaces.

Commonly encountered defects in whipping cream arise when large triglyceride crystals, formed in masses of free fat, adsorb to the air/water interface during whipping at the expense of fat globules.

In other food systems , …

The Stabilisation Of Air In Cake Batters - The Role Of Fat, B. E. Brooker

Food Structure

The role of fat crystals in the stabilisation of air bubbles in cake batters was studied with aqueous phase aerations prepared by the "all in one" method using shortening containing emulsifier. During mixing, fat crystals become coated with an interfacial layer of ad sorbed protein (crystal -water interface). They adsorb to the surface of bubbles (that have been transiently stabilised by egg proteins) by a process which involves the fu sion of the crystal-water interface with the air-water interface.

The adsorption of fa t crystals helps to stabilise large numbers of small bubbles which must expand without rupturing during baking …

Effect Of Lactose And Protein On The Microstructure Of Dried Milk, V. V. Mistry, H. N. Hassan, D. J. Robison

Food Structure

Skim milk of approximately 3% total protein was ultrafiltered to 16.2% protein and 4.1 % lactose, and then diafiltered to reduce lactose to 2.1% and 0.9%. Total protein con ten t was maintained at approximately 17%. A ponion of the skim milk was condensed in a rising film evaporator to 14.7% protein and 15.7% lactose . All concentrates were spray dried at 120 to 125 °C inlet air temperature and 75 to 80 C outlet temperature using a rotary atomizer in a pilot plant spray dryer . Moisture content of the powders were 4.7 to 6.3% and lactose content ranged …

Comparison Of The Effects Of Three Different Grinding Procedures On The Microstructure Of "Old-Fashioned" Non-Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

Three different grinding procedures were utilized to prepare "old-fashioned" non-stabilized peanut butters. A leading commercial brand of stabilized peanut butter was used for comparison. The microstructure of each non-stabilized peanut butter was then evaluated with light microscopy and compared to the microstructure of the commercial brand of stabilized peanut butter. Major findings include: (1) dense spatial relationships of protein bodies, starch grains, and cell and tissue fragments that exist in "old-fashioned " non-stabilized peanut butter as compared to the well-dispersed spatial relationships which exist in commercially prepared stabilized peanut butter; and (2) degree of homogenization in the nonstabilized peanut butters …

Structure And Rheology Of Dairy Products: A Compilation Of References With Subject And Author Indexes, David N. Holcomb

Food Structure

No abstract provided.

A Method For The Examination Of The Microstructure Of Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

A method for light and scanning electron microscopy of damaged resting peanut seed tissue was adapted as a research tool for evaluating the microstructural features of commercially available stabilized peanut butter. This method was used in the present study to evaluate the degree of homogenization of stabilized peanut butter by examining the spatial relationship which exists among the microstructural features. Light and scanning electron microscopy of three commercially available stabilized peanut butters revealed varying degrees of homogenization of broken cell and tissue fragments, protein bodies, and starch grains within a matrix of stabilized oil.

Transmission And Scanning Electron Microscopy Of Peanut (Arachis Hypogaea L. Cv. Florigiant) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachis~ L. cv. Florigiant) cotyledon after roasting at a temperature of 160°C for 16 minutes were investigated with transmission and scanning electron microscopy. Thermal modifications were documented with photomicrographs of t he cytoplasmic network , protein bodies, starch grains and cell-to-cell junctions after oven roasting. These thermal modifications include disruption of the cytoplasmic network, distension of protein bodies, decreased stain affinity of starch grains , and disintegration of middle lamellae in some cell-t o-cell junctions.

Heat-Set Gels Based On Oil/Water Emulsions: An Application Of Whey Protein Functionality, R. Jost, F. Dannenberg, J. Rosset

Food Structure

The microstructure of portein/lipid gels produced by heat treatment of whey protein stabilized oil-in-water(O/W) emulsions was studied. Scanning electron microscopy as well as transmission electron microscopy was performed on glutaraldehyde/osmium tetroxide fixed, and critical point-dried samples. Microstructure analysis showed that in the case of homogenized O/W emulsions, extensive coating of the fat globule surface with coagulated protein led to a "cauliflower - like" structure. In such gels, uncoated fat globules having smooth surfaces were not present. This specific microstructure was not obtained with protein/lipid gels in which whey protein was added in the continuous phase and mixed with a O/W …

Changes In The Ultrastructure Of Emulsions As A Result Of Electron Microscopy Preparation Procedures, M. Liboff, H. D. Goff, Z. Haque, W. K. Jordan, J. E. Kinsella

Food Structure

Various methods of preparing emulsions for electron microscopy were examined with peanut oil/protein and ice cream mix emulsions. For transmission electron microscopy {TEM) , fresh peanut oil/bovine serum albumin emulsions were mixed with 2% agar , fixed in phosphate-buffered (pH 7 . 0) 4% glutaraldehyde solution and postfixed in phosphate-buffered (pH ? . 0) 1% osmium tetroxide alternatively , the glutaraldehyde- fixed samples were briefly rinsed in acetone prior to postfixation . Both preparations yielded satisfactory fat globule preservation. Similar emulsions were prepared on loops and suspended over vapors of 25% gJ nt.RrBl r'lehyr'le Rnc'l 1% oRmi urn tetroxide . …

Microstructural Studies Of Texturized Vegetable Protein Products: Effects Of Oil Addition And Transformation Of Raw Materials In Various Sections Of A Twin Screw Extruder, S. Gwiazda, A. Noguchi, K. Saio

Food Structure

In high-temperature short- time extrusion cooking with a twin screw extruder , effects of oil addition to defatted soybean flour and microstructural transformation of full - fat soybean flour during cooking , were investigated by use of a light microscope. At levels up to 15% , soybean oil was distributed in the protein and carbohydrate matrix as small, spherical drops under the experimental conditions used in this study. However , oil contents above 15% significantly prevented formation of well-aligned fibrous structures in the extrudates . During extrusion cooking , the starting materials began to break down by shearing and kneading …

Fluorescence Characterization Of The Mature Caryopsis Of Sorghum Bicolor (L.) Moench, C. F. Earp, L. W. Rooney

Food Structure

Fluorescence microscopy was used to characterize the mature car yaps is of Sorghum bicolor (L.) Moench . Acid Fuchsin, a protein specific dye used in bright field microscopy, caused protein bodies and matrix in the sorghum endosperm to fluoresce. ANS (8-ani lino-1- naphthal e ne sulfonic acid) also caused the protein bodi es and matrix in the endosperm to fluoresce. Varietal differences in endosperm protein dist r ibution were evident when viewed after sta · ning with Acid Fuchsin . Nile Blue A caused fl uorescence in neutral lipids such as those in :he lipid bodies in the aleurone and …

Current Concepts Of Muscle Ultrastructure With Emphasis On Z-Line Architecture, M. Yamaguchi, H. Kamisoyama, S. Nada, S. Yamano, M. Izumimoto, Y. Hirai, R. G. Cassens, H. Nasu, M. Muguruma, T. Fukazawa

Food Structure

Invertebrate striated muscle, the Z-line, which defines the sarcomere length, presents diverse structural patterns both in cross section and in longitudinal section. Conflicting models have been proposed to explain the microscopic observations. The protein composition of the Z- line structure is unresolved. o: -Actin in is widely accepted as a Z-line component, and actin filaments extend into wide Z-lines. Based on recent findings from our laboratory and others, we developed a new model applicable to wide and narrow Z-lines. The model allowed the observed ultrastructural patterns of Z-lines to be simulated. Improved electron microscopic techniques should allow further progress to …

Does The Embedding Chemistry Interact With Tissue?, B. E. Causton

Scanning Electron Microscopy

Resins and resin compounds interact with tissue in two ways, physico-chemically and by chemical reaction. The physico-chemical influences affect both the structure and biological activity of the tissue causing proteins to change shape or phase equilibria to be disrupted by a change in solvent or by the growth of polymer networks within existing biological polymeric structures. Chemical reactivity between tissue and resin components also reduces biological activity by changing either the structure of polymeric matter already present, e.g., crosslinking proteins, grafting hydrophobic resins onto hydrophilic protein backbones, or by modifying the hydrophobicity of specific sites, e.g., acylation of amino groups …

The Morphology Of Thin Metal Coatings Formed By Rotary Shadowing Biological Species In High Vacuum, J. A. Panitz

Scanning Electron Microscopy

Rotary Shadowing has been used to increase the image contrast of biological species observed during edge-projection imaging in the transmission electron microscope. In this imaging mode, biological species are adsorbed from aqueous solutions onto a highly curved substrate and viewed, over its edge, in a direction parallel to its surface. Since the substrate is not placed between a biological adsorbate and the photographic emulsion that records its image, any material can be used as a support (including high-Z metals and semiconductors). Binding to these technologically interesting materials is observed with unusual clarity and contrast, even at 200kV. Individual adsorbates and …

Characterisation Of Milk Proteins In Confectionery Products, J. F. Heathcock

Food Structure

The proteins from milk play an important part in the structural properties of confectionery products. These properties will in turn influence texture and flavour. Electron microscopy techniques have been used to examine milk chocolate, caramel and fudge and to locate and characterise the milk proteins within their structures. Following scanning electron microscopy examination of the products at low temperature, thin sectioning and freeze-fracture were used to resolve the fine ultrastructure of casein and whey proteins.

A chocolate prepared from milk crumb could be distinguished from one made with a dry milk powder on the basis of a more even distribution …

An Alternive To Critical Point Drying For Preparing Meat Emulsions For Scanning Electron Microscopy, Edward J. Basgall, Peter J. Bechtel, Floyd K. Mckeith

Food Structure

A rapid sample drying technique is described which is useful for the simultaneous preparation of large numbers of samples as an alternative to critical point drying. The cryofractured face of meat emulsions was visualized after appl ying this technique . The fine structure of 1 ipids and proteins were found to be well preser ved in comparison to other reports which used critical point dried meat emulsions. Lipid was readily discerned from the protein matrix by selective fixation of the components in duplicate samples . Stereo imaging was useful in enhancing the texture of the cryofractured surface and as an …

Fluorescence Microscopy Of Cereals, R. G. Fulcher

Food Structure

The fluorescence microscope is one of the most sensitive instruments available for morphological and microchemical analysis of biological material, and especially of cereal grains. Recent innovations in illuminating systems, fluorescence chemistry, and specimen preparation have combined to provide significant improvements over conventional bright-field microscopy in both specificity and sensitivity. A variety of relatively specific fluorescent markers has been devised for routine and high resolution detection of all major cereal components. Several examples of useful fluorescent markers are described, including appropriate methods for specimen preparation, fluorescence analysis, and photography.