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1995

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Articles 31 - 60 of 324

Full-Text Articles in Biology

Zinc Deficiency Produces Time-Related Ultrastructural Changes In Rat Cheek Epithelium, Shahid H. Ashrafi, Nasser A. H. Said-Al-Naief Nov 1995

Zinc Deficiency Produces Time-Related Ultrastructural Changes In Rat Cheek Epithelium, Shahid H. Ashrafi, Nasser A. H. Said-Al-Naief

Scanning Microscopy

The subject of this study was whether the ultrastructural changes in cheek epithelium of zinc-deficient rats are time related. Weanling male Sprague Dawley rats were fed a zinc-deficient diet containing 0.4 ppm zinc (ZD) ad libitum and controls were pair-fed zinc adequate diet containing 40 ppm zinc. After 9, 18, and 27 days of zinc deficiency, specimens from cheek epithelium of both groups were processed for transmission electron microscopy. Partial conversion of the orthokeratinized cheek epithelium to parakeratinized was seen as early 9 days. An electron-lucent band surrounding the nucleus was observed in ZD cells. Mitochondria, tonofilaments, keratohyalin granules and …

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Immunogold Labeling For The Diagnosis Of Leukemia By Transmission And Scanning Electron Microscopy, Etienne De Harven, Davide Soligo, Hilary Christensen Nov 1995

Immunogold Labeling For The Diagnosis Of Leukemia By Transmission And Scanning Electron Microscopy, Etienne De Harven, Davide Soligo, Hilary Christensen

Scanning Microscopy

For the cell type diagnosis of leukemia in adult patients, particularly when the sampling of bone marrow is difficult, the study of peripheral blood leukocytes (PBLs) by immuno-electron microscopy provides significant information, as illustrated here in two cases of hairy cell leukemia and seven cases tentatively identified as megakaryoblastic leukemia (M7). Indirect immunogold labeling with the B-ly7 monoclonal antibody (CD103) proved valuable in confirming the diagnosis of hairy cell leukemia. Immunogold labeling for the GplIIa platelet glycoprotein (CD61) was used in cases where the light microscopy of blood films revealed possible megakaryoblastic leukemia. Under the electron microscope, however, the CD61 …

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Alterations In Intestinal Transport Of Oxalate In Disease States, Marguerite Hatch, Robert W. Freel Nov 1995

Alterations In Intestinal Transport Of Oxalate In Disease States, Marguerite Hatch, Robert W. Freel

Scanning Microscopy

Normally, absorption of oxalate from dietary sources can occur in all segments of the intestinal tract. However, alterations in both the magnitude and direction of oxalate fluxes across the intestine can occur in disease states. In enteric hyperoxaluria, enhanced absorption of oxalate by the large intestine is caused by increased permeability of a shunt conductance induced by malabsorbed bile salts and fatty acids. In this condition, the contribution of a paracellular passive flux of oxalate moving along its electrochemical gradient will predominate when intraluminal concentrations of free oxalate are high. In contrast, in chronic renal failure, secretion of oxalate can …

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Zeta Potential Measurement And Particle Size Analysis For A Better Understanding Of Urinary Inhibitors Of Calcium Oxalate Crystallization, L. C. Cao, G. Deng, E. R. Boeve, W. C. De Bruijn, R. De Water, C. F. Verkoelen, J. C. Romijn, F. H. Schroder Nov 1995

Zeta Potential Measurement And Particle Size Analysis For A Better Understanding Of Urinary Inhibitors Of Calcium Oxalate Crystallization, L. C. Cao, G. Deng, E. R. Boeve, W. C. De Bruijn, R. De Water, C. F. Verkoelen, J. C. Romijn, F. H. Schroder

Scanning Microscopy

To better understand urinary inhibitors of calcium oxalate crystallization, both zeta potential measurement and particle size analysis were chosen to illustrate: (1) the potential therapeutic efficacy of G872, a semi-synthetic sulfated polysaccharide, in stone prevention; and (2) the relative contribution of various urinary fractions {e.g., ultrafiltered urine (UFU), Tamm-Horsfall protein (THP), urinary polyanionsprecipitated with cetylpyridinium chloride (CPC), urinary macromolecular substances with different concentration ratios (UMSl0,50,90 and UMS'l0,50,90) and THP-free urine (THPFU)} to total urinary inhibitory activity. The results showed: (1) addition of G872 significantly enhances urinary inhibitory activity and negative zeta potential values; (2) re-addition of the CPC to UFU …

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Incorporating Depredation Permits Into Integrated Damage Management Plans For Aquaculture Facilities, Philip Mastrangelo, Charles Sloan, Kevin Bruce Nov 1995

Incorporating Depredation Permits Into Integrated Damage Management Plans For Aquaculture Facilities, Philip Mastrangelo, Charles Sloan, Kevin Bruce

Wildlife Damage Management Conference

Increasing bird depredation at aquaculture facilities in Alabama, Arkansas, Louisiana, and Mississippi creates economic hardships for many fish farmers. Solutions to bird depredation at these facilities require the development of integrated damage management plans that will reduce damage levels while insuring minimal impacts to bird populations. Damage management plans developed for fish farmers by the U.S. Department of Agriculture, Animal and Health Plant Inspection Service, Animal Damage Control (ADC) program always include non-lethal control recommendations. If nonlethal control is ineffective or only marginally effective in reducing damage, the management plans may also recommend the issuance of depredation permits by the …

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Comparison Of Predation Rates On Wild Turkey Hens Between Two Forest Ecosystems In Mississippi, Michael J. Chamberlain, Darren A. Miller, Bruce D. Leopold, George A. Hurst Nov 1995

Comparison Of Predation Rates On Wild Turkey Hens Between Two Forest Ecosystems In Mississippi, Michael J. Chamberlain, Darren A. Miller, Bruce D. Leopold, George A. Hurst

Wildlife Damage Management Conference

Because of increases in predator populations, concern has arisen about effects on wild turkey (Meleagris gallopavo) populations. We examined differences in predation of adult hens between 2 forested areas in Mississippi. Twin Oaks Wildlife Management Area (OAKS), located in the Mississippi Alluvial Valley, is a 2,302 ha tract of mature bottomland hardwood forest surrounded on 3 sides by soybean fields. Tallahala Wildlife Management Area (TWMA) is a 14,410 ha mixed forest in central Mississippi and is part of a large, forested ecosystem. Hens were captured, fitted with transmitters, and monitored by telemetry, 1990-1994 on TWMA (n = …

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Pseudomonas Aeruginosa Strain Ma01 Aerobically Metabolizes The Aminodinitrotoluenes Produced By 2,4,6-Trinitrotoluene Nitro Group Reduction, Mark A. Alvarez, Christopher Kitts, James L. Botsford, Pat J. Unkefer Nov 1995

Pseudomonas Aeruginosa Strain Ma01 Aerobically Metabolizes The Aminodinitrotoluenes Produced By 2,4,6-Trinitrotoluene Nitro Group Reduction, Mark A. Alvarez, Christopher Kitts, James L. Botsford, Pat J. Unkefer

Biological Sciences

Many microbes reduce the nitro substituents of 2,4,6-trinitrotoluene (TNT), producing aminodinitrotoluenes (ADNTs). These compounds are recalcitrant to further breakdown and are acutely toxic. In a search for organisms capable of metabolizing ADNTs, a bacterial strain was isolated for the ability to use 2-aminobenzoate (anthranilate) as sole C-source. This isolate, Pseudomonas aeruginosa MAO1, metabolized TNT by first reducing one nitro group to form either 2-amino-4,6-dinitrotoluene (2ADNT) or 4 -amino-2,6-dinitrotoluene(4ADNT). However, strain MA01 was distinct from other TNT-reducing organisms in that it transformed these compounds into highly polar metabolites through an 02-dependent process. Strain MAOl was able to cometabolize TNT, 2ADNT, and …

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Responses To Toxicants Of An Escherichia Coli Strain Carrying A Uspa'::Lux Genetic Fusion And An E. Coli Strain Carrying A Grpe'::Lux Fusion Are Similar, T. K. Van Dyk, D. R. Smulski, T. R. Reed, S. Belkin, Amy Cheng Vollmer, R. A. Larossa Nov 1995

Responses To Toxicants Of An Escherichia Coli Strain Carrying A Uspa'::Lux Genetic Fusion And An E. Coli Strain Carrying A Grpe'::Lux Fusion Are Similar, T. K. Van Dyk, D. R. Smulski, T. R. Reed, S. Belkin, Amy Cheng Vollmer, R. A. Larossa

Biology Faculty Works

A transcriptional fusion of the Escherichia coli uspA promoter to luxCDABE was characterized and compared with a heat shock-responsive grpE'::lux fusion. Similarities in range and rank order of inducing conditions were observed; however, the magnitude of induction was typically greater for the grpE'::lux fusion strain.

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In Situ Of Interferon On Human Glioma Protein Kinase C-Α And -Β Ultrastructural Localization, Mildred Acevedo-Duncan, John Collins, Ruonana Zhang, Edward M. Haller, Charles E. Chalfant, Denise R. Cooper Nov 1995

In Situ Of Interferon On Human Glioma Protein Kinase C-Α And -Β Ultrastructural Localization, Mildred Acevedo-Duncan, John Collins, Ruonana Zhang, Edward M. Haller, Charles E. Chalfant, Denise R. Cooper

Integrative Biology Faculty and Staff Publications

Transmission electron microscopy was used to determine how immunogold labeling of PKC-alpha or -beta is modulated by the antitumor drug IFN (HuIFN alpha-2b) in the cytoplasm, membrane structures, and nucleus of rapidly dividing and confluent human glioma U-373 cells. Results showed that except for nuclear localization, there were no specific cytoplasmic organelles that PKC-alpha or -beta translocated to following HuIFN alpha-2b treatment. Electron micrographs of PKC-beta in proliferating cells depicted 1.34-fold more PKC-beta in the nucleus than in the cytoplasm and a 1-min HuIFN alpha-2b (500 units/ml) treatment transiently increased PKC-beta immunoreactivity in the cytoplasm (1.95-fold) and nucleus (1.97-fold). In …

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The Mayfly Newsletter, Peter M. Grant Nov 1995

The Mayfly Newsletter, Peter M. Grant

The Mayfly Newsletter

The Mayfly Newsletter is the official newsletter of the Permanent Committee of the International Conferences on Ephemeroptera.

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Use Of Elisa For Determination Of Plasma Prolactin Levels In The House Wren, Given Harper, Sharon Sintich, Michelle Keagle, Ian Welsford Nov 1995

Use Of Elisa For Determination Of Plasma Prolactin Levels In The House Wren, Given Harper, Sharon Sintich, Michelle Keagle, Ian Welsford

Scholarship

Prolactin concentrations in avian plasma have been traditionally quantified using a radioimmunoassay (RIA) procedure. RIA is useful for such studies due to its sensitivity and specificity (e.g., Follett et al. 1972, Wingfield and Farner 1975, McNeilly et al. 1978, Burke and Papkoff 1980, Schwabl 1993). For example, the heterologous RIA for detecting prolactin in turkeys, developed by McNeilly et al. (1978), recovered 98% of a prolactin standard added to a turkey plasma sample and exhibited less than 0.1% cross reactivity with other plasma hormones. In an homologous RIA developed by Burke and Papkoff (1980), detection limits of approximately 0.42 ± …

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Effect Of Hindlimb Unloading On Rat Soleus Fiber Force, Stiffness, And Calcium Sensitivity, Kerry S Mcdonald, Robert H. Fitts Nov 1995

Effect Of Hindlimb Unloading On Rat Soleus Fiber Force, Stiffness, And Calcium Sensitivity, Kerry S Mcdonald, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to examine the time course of change in soleus muscle fiber peak force (N), tension (Po, kN/m2), elastic modulus (Eo), and force-pCa and stiffness-pCa relationships. After 1, 2, or 3 wk of hindlimb unloading (HU), single fibers were isolated and placed between a motor arm and a transducer, and fiber diameter, peak absolute force, Po, Eo, and force-pCa and stiffness-pCa relationships were characterized. One week of HU resulted in a significant reduction in fiber diameter (68 +/- 2 vs 57 +/- 1 microns), force …

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Scanning Electron Microscopy Of Cyclosporine-Induced Gingival Overgrowth, Shahid H. Ashrafi, Krzysztof Slaski, Kyaw Thu, Eli S. Neiman, Michael P. Cunningham Oct 1995

Scanning Electron Microscopy Of Cyclosporine-Induced Gingival Overgrowth, Shahid H. Ashrafi, Krzysztof Slaski, Kyaw Thu, Eli S. Neiman, Michael P. Cunningham

Scanning Microscopy

Overgrown human gingival specimens were examined histologically and by scanning electron microscopy (SEM) to study structural changes caused by cyclosporine. The biopsy specimens were from organ transplant recipients receiving cyclosporine to suppress the rejection of the transplanted organ. The epithelium of the overgrown gingiva was thickened, acanthotic and parakeratotic. Retepegs were anastomosing and extending into connective tissue. The SEM examination of the outer surface of the attached gingival showed loss of cellular attachments and cells were exfoliating. The normal honeycomb structure formed by interconnecting microvilli surrounding the pits was distorted. Outer gingival cell surface showed numerous round, ovoid and dome-like …

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Examination Of Injected Specimens By Confocal Laser Scanning Microscopy And Scanning Electron Microscopy, A. Castenholz Oct 1995

Examination Of Injected Specimens By Confocal Laser Scanning Microscopy And Scanning Electron Microscopy, A. Castenholz

Scanning Microscopy

Although corrosion casts commonly examined by scanning electron microscopy (SEM) offer good insights into the general arrangement of the microvasculature of certain organs, no information can be obtained from such specimens on special morphological data or dynamic events. Thus, most investigators are obliged to make their interpretations of cast structures only on the basis of indirect criteria. A synopsis, which considers the most important data in that respect, is given for the blood and lymphatic microvessels. Moreover, a methodological approach is introduced, based on the application of fluorescent resin, which allows the examination of cast structures in uncorroded specimens together …

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Dietary Oxalate And Its Intestinal Absorption, Ross P. Holmes, Harold O. Goodman, Dean G. Assimos Oct 1995

Dietary Oxalate And Its Intestinal Absorption, Ross P. Holmes, Harold O. Goodman, Dean G. Assimos

Scanning Microscopy

Dietary oxalate is currently believed to make only a minor contribution (< 20%) to urinary oxalate excretion. A recent prospective study of stone disease suggested that dietary oxalate may be a significant risk factor. This observation led us to re-evaluate the contribution of dietary oxalate to urinary oxalate excretion. Previous studies have been hampered by inaccurate food composition tables for oxalate and inadequate methods for studying intestinal oxalate absorption. This evidence as well as factors that modify oxalate absorption are reviewed. New approaches to measure food oxalate and intestinal oxalate absorption have been examined. Capillary electrophoresis appears to be well suited for the analysis of the oxalate content of food. Two individuals consumed an oxalate-free formula diet for 7 days. This diet decreased urinary oxalate excretion by an average of 67% (18.6 mg per 24 hours) compared to oxalate excretion on self-selected diets. The absence of detectable oxalate in feces by day 6 of the diet suggested that the intestinal absorption was minimal. However, an effect of the formula diet on endogenous oxalate synthesis cannot be excluded. Restoring oxalate to the formula diet increased urinary oxalate excretion and illustrates that this experimental protocol may be well-suited for studying oxalate absorption and factors that modify it. Our results suggest that the intestinal absorption of dietary oxalate makes a substantial contribution to urinary oxalate excretion and that this absorption can be modified by decreasing oxalate intake or increasing the intakes of calcium, magnesium, and fiber.

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Elliptical-P Cells In The Avian Perilymphatic Interface Of The Tegmentum Vasculosum, C. D. Fermin, D. H. Lee, D. S. Martin Oct 1995

Elliptical-P Cells In The Avian Perilymphatic Interface Of The Tegmentum Vasculosum, C. D. Fermin, D. H. Lee, D. S. Martin

Scanning Microscopy

Elliptical cells (E-P) are present at the perilymphatic interface lumen (PIL) of the lagena. The E-P cells often separate from the tegmentum vasculosum (TV) and have touching processes that form a monolayer between the K+ rich perilymph and the Na+ rich endolymph, similar to the mammalian Reissner's membrane. We examined the TV of chicks (Gallus domesticus) and quantitated the expression of anti-S100ααββ and S100β. There was a 30% increase of S100β saturation in the light cells facing the PIL when compared to other TV light cells. We show that: (1) the dimer anti-S100ααββ and …

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Scanning Probe Microscope Gigahertz Measurements On 200 Nanometer Wave Guides, C. Böhm, J. Sprengepiel, E. Kubalek Oct 1995

Scanning Probe Microscope Gigahertz Measurements On 200 Nanometer Wave Guides, C. Böhm, J. Sprengepiel, E. Kubalek

Scanning Microscopy

Scanning probe microscopy is opening new applications in microelectronic engineering due to easy and reliable instrumentation in combination with superior resolution limits without any sample preparation under ambient conditions. Beside the standard topography imaging possible application are static and dynamic surface potential measurements, doping profiling, and scanning thermal applications. In this paper, we report dynamic voltage contrast measurements of analog and digital gigahertz signals on 200 nm wave guides within integrated microelectronic devices and components. The results are obtained by using a time resolved device internal test technique based on a scanning force microscope using the electrostatic force interaction. This …

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Penetration Of Positrons In Solid Targets, Maurizio Dapor Oct 1995

Penetration Of Positrons In Solid Targets, Maurizio Dapor

Scanning Microscopy

The study of the interaction of positron beams with solid targets has been approached by several investigators, also due to its importance for positron annihilation spectroscopy. This technique allows non-destructive investigations of the structural defects of surfaces and interfaces: in particular information is provided about the nature and distribution of point defects in solid materials. The solution of the diffusion equation, necessary to obtain the fractions of incident positrons annihilated at different depths inside the target, requires the knowledge of the positron stopping profile, i.e., the initial depth distribution of the thermalized positrons. Also transmission of positrons is of great …

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Atomic Force Microscopy Study Of Fine Structures Of The Entire Surface Of Red Blood Cells, P. -C. Zhang, C. Bai, Y. -M. Huang, H. Zhao, Y. Fang, N. -X. Wang, Q. Li Oct 1995

Atomic Force Microscopy Study Of Fine Structures Of The Entire Surface Of Red Blood Cells, P. -C. Zhang, C. Bai, Y. -M. Huang, H. Zhao, Y. Fang, N. -X. Wang, Q. Li

Scanning Microscopy

Glutaraldehyde-fixed red blood cells were imaged by tapping mode atomic force microscopy (TMAFM) in air at room temperature. The results show that TMAFM can visualize the morphology of the red blood cell at both cellular and nanometer scales. The scan size covers the range from several hundred nanometers to more than one hundred micrometers. TMAFM not only has a higher resolution than the optical microscope, but also can observe biological samples without precoating as required for scanning electron microscopy (SEM). The AFM images of the entire surface of an uncoated red blood cell with nanometer resolution are successfully reconstructed by …

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Vascular Architecture Of The Lactating And Non-Lactating Teat Of The Bitch: A Scanning Electron- And Light Microscope Study, F. J. Pérez-Aparicio, V. Dantzer, M. Navarro, A. Carretero, J. Ruberte Oct 1995

Vascular Architecture Of The Lactating And Non-Lactating Teat Of The Bitch: A Scanning Electron- And Light Microscope Study, F. J. Pérez-Aparicio, V. Dantzer, M. Navarro, A. Carretero, J. Ruberte

Scanning Microscopy

Tissues from fourteen mammary glands of eight bitches were prepared for scanning electron microscopy of vascular corrosion casts and for histology to study the vasculature of the lactating and non-lactating teats. The densely-meshed mammary dermal capillary network formed ridges and troughs. The teat ducts were vascularized by a relatively densely-meshed capillary network which drained into veins longitudinally oriented to the ducts. Between eight and fifteen teat duct openings were seen on the tip of the teat, that were sometimes divided by a septum. The inner vascularization of the teat showed that the main papillary arteries divided into undulating secondary papillary …

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Photoemission And Free Electron Laser Spectromicroscopy: Photoemission At High Lateral Resolution, G. Margaritondo Oct 1995

Photoemission And Free Electron Laser Spectromicroscopy: Photoemission At High Lateral Resolution, G. Margaritondo

Scanning Microscopy

The move of photoemission analysis from the macroscopic to the microscopic domain has been accelerated by the advent of new ultrabright synchrotron sources of soft-X-rays. This makes an overview of photoemission spectromicroscopy, photoemission at high lateral resolution, quite timely. The overview begins with the basic concepts and problems, both technical and of data-taking strategy. Then, it presents a small number of examples of results in physics and biology, such as local chemical fluctuations in superconductors, semiconductor interfaces and the microchemistry of biological systems. The presentation includes the first experimental results from two new ultrabright synchrotron facilities: ELETTRA (in Italy) and …

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Different Approaches To The Study Of Apoptosis, E. Falcieri, L. Stuppia, A. Di Baldassarre, A. R. Mariani, C. Cinti, M. Columbaro, L. Zamai, M. Vitale Oct 1995

Different Approaches To The Study Of Apoptosis, E. Falcieri, L. Stuppia, A. Di Baldassarre, A. R. Mariani, C. Cinti, M. Columbaro, L. Zamai, M. Vitale

Scanning Microscopy

The morphological features of cell undergoing programmed cell death is well known and has been widely described in a number of experimental models with a variety of apoptotic triggering agents. Despite the similar cell behaviour, underlying molecular events seem variable and only partially understood. A multiple approach appears crucial to better clarify the phenomenon. The first technique, DNA gel electrophoresis, allows the identification of fragmented DNA and has been long considered the hallmark of apoptosis. Different patterns of DNA cleavage, which can be identified by conventional or "pulsed-field gel" electrophoresis, are presented and discussed. "In situ" labelling methods are also …

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Oxalate-Induced Damage To Renal Tubular Cells, C. R. Scheid, H. K. Koul, L. Kennington, W. A. Hill, J. Luber-Narod, J. Jonassen, T. Honeyman, M. Menon Oct 1995

Oxalate-Induced Damage To Renal Tubular Cells, C. R. Scheid, H. K. Koul, L. Kennington, W. A. Hill, J. Luber-Narod, J. Jonassen, T. Honeyman, M. Menon

Scanning Microscopy

Our own studies and those of others have shown that the incidence of calcium oxalate stones and plaques is markedly increased by nephrotoxins. The possible role of oxalate as a nephrotoxin has not been fully appreciated. However, recent studies in experimental animals and in cultured cells support this possibility. The results of these studies led us to hypothesize that hyperoxaluria promotes stone formation in several ways: by providing a substrate for the formation of the most common form of renal stones, calcium oxalate stones, and by inducing damage to renal epithelial cells. Damaged cells in turn would produce an environment …

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Synergistic Induction Of The Heat Shock Response In Escherichia Coli By Simultaneous Treatment With Chemical Inducers, T. K. Van Dyk, T. R. Reed, Amy Cheng Vollmer, R. A. Larossa Oct 1995

Synergistic Induction Of The Heat Shock Response In Escherichia Coli By Simultaneous Treatment With Chemical Inducers, T. K. Van Dyk, T. R. Reed, Amy Cheng Vollmer, R. A. Larossa

Biology Faculty Works

No abstract provided.

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Transport And Metabolism Of Alanine And Palmitic Acid By Field-Collected Larvae Of Tedania Ignis (Porifera, Demospongiae): Estimated Consequences Of Limited Label Translocation, William B. Jaeckle Oct 1995

Transport And Metabolism Of Alanine And Palmitic Acid By Field-Collected Larvae Of Tedania Ignis (Porifera, Demospongiae): Estimated Consequences Of Limited Label Translocation, William B. Jaeckle

Scholarship

The epidermis of larvae of Tedania ignis(Porifera, Demospongiae) is uniformly ciliated except for the posterior pole. The epidermal cells are long, columnar, and monociliate; each cilium arises from an epidermal crypt; symbiotic bacteria were not observed in larval cells. These lecithotrophic ("nonfeeding") larvae can feed by assimilating dissolved organic materials (DOM) from seawater. Larvae transported both the amino acid alanine (mean = 2.73 pmol larva-1 h-1; [S] = 1 µM) and the fatty acid palmitic acid (mean = 16.27 pmol larva-1 h-1; [S] = 1 µM) from seawater. Following assimilation, the …

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In Situ Hybridization And Monoclonal Antibody Analysis Of Plasma Membrane Ca-Pump Mrna And Protein In Submandibular Glands Of Rabbit, Rat And Man, J. L. Borke, A. E. Zaki, D. R. Eisenmann, S. H. Ashrafi, M. M. Sharawy, S. S. Rahman Sep 1995

In Situ Hybridization And Monoclonal Antibody Analysis Of Plasma Membrane Ca-Pump Mrna And Protein In Submandibular Glands Of Rabbit, Rat And Man, J. L. Borke, A. E. Zaki, D. R. Eisenmann, S. H. Ashrafi, M. M. Sharawy, S. S. Rahman

Scanning Microscopy

The degree of supersaturation of saliva with calcium (Ca) is related to the mineral phase of enamel in erupted teeth, the incidence of caries, and the formation of calculus. The mechanisms for regulating salivary Ca concentration are therefore of relevance to dentistry. Sections of rabbit, rat and human submandibular gland (SMG) were processed for immuno-histochemistry with a specific anti-plasma membrane Ca-pump antibody, 5F10. Western blots confirm that the molecular weight of the proteins identified by our antibody (135 kDa) is consistent with an appropriate molecular weight for PMCA antigen (135-150 kDa). Tissue sections were also processed for in situ hybridization …

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Contribution Of Conventional And High Resolution Scanning Electron Microscopy And Cryofracture Technique To The Study Of Cerebellar Synaptic Junctions, Orlando J. Castejón Sep 1995

Contribution Of Conventional And High Resolution Scanning Electron Microscopy And Cryofracture Technique To The Study Of Cerebellar Synaptic Junctions, Orlando J. Castejón

Scanning Microscopy

The cerebelli of teleost fishes, primates and humans were processed for conventional and high resolution scanning electron microscopy (SEM) to study the outer and inner surfaces of axo-dendritic, glomerular and axo-somatic synapses. The cryofracture technique, either by slow or fast freezing, exposed the hidden neuronal surfaces of synaptic connections, selectively removing the glial ensheathment. Axo-dendritic junctions of climbing fibers and Golgi axonal ramifications were studied in gold-palladium and chromium coated samples. Chromium coating showed different mass density and topographic contrast between axonal and dendritic profiles. Conventional SEM of cryofractured glomerular synapses exhibited the outer surface view of en passant mossy …

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X-Irradiation-Induced Disorganization Of Cytoskeletal Filaments And Cell Contacts In Ht29 Cells, Z. Somosy, M. Sass, G. Bognar, J. Kovacs, G. J. Koteles Sep 1995

X-Irradiation-Induced Disorganization Of Cytoskeletal Filaments And Cell Contacts In Ht29 Cells, Z. Somosy, M. Sass, G. Bognar, J. Kovacs, G. J. Koteles

Scanning Microscopy

Organization of cytoskeleton and cell contacts were studied by immunochemistry and electron microscopy in confluent HT29 cultured cells following exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were resistant to irradiation, whereas, the actin and intermediate filaments disrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as demonstrated by immunochemistry. Loss of cell contacts and decrease in the number of desmosomes was also characteristic of irradiated cells. Electron microscopy revealed intact desmosomes in control cells and abnormal desmosomes in the irradiated samples characterized by the absence of tonofilaments. …

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A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E Lyons, J Erker, A Ernst Sep 1995

A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E Lyons, J Erker, A Ernst

Biology Department Faculty Works

In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-galactoside substrate for in situ localization of gene expression, we have shown that the two clusters of nif genes are expressed independently. One nitrogenase functions only in heterocysts under either aerobic or anaerobic growth conditions, whereas the second nitrogenase functions only under anaerobic conditions in vegetative cells and heterocysts. …

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Dental Abnormalities And Early Diagnosis Of Hyperphosphatasemia, M. J. Bottero-Cornillac, A. Gaucher, C. Wang, M. Chaussidon, J. Yvon Sep 1995

Dental Abnormalities And Early Diagnosis Of Hyperphosphatasemia, M. J. Bottero-Cornillac, A. Gaucher, C. Wang, M. Chaussidon, J. Yvon

Scanning Microscopy

Dental hard tissue abnormalities have never been described as part of the symptoms associated with hyperphosphatasemia. Fourteen teeth obtained from a young man, who had a mild form of hyperphosphatasemia, were analyzed using scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD), and infrared (IR) spectroscopy. SEM revealed a thin enamel, presenting a prismatic structure with many pits, and atypical cementum and dentin showing numerous resorption areas. The X-ray diffractograms revealed poorly crystallinehydroxyapatite associated with α-tricalcium phosphate and magnesium hydroxide phases. SIMS data showed high Ca concentrations: 40.5 weight % {wt%; standard deviation (SD) = 0.13) …

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