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1999

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Articles 1 - 30 of 102

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor Ambros Dec 1999

Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor Ambros

Open Dartmouth: Faculty Open Access Articles

During postembryonic development of Caenorhabditis elegans, the heterochronic gene lin-14 controls the timing of developmental events in diverse cell types. Three alternativelin-14 transcripts are predicted to encode isoforms of a novel nuclear protein that differ in their amino-terminal domains. In this paper, we report that the alternative amino-terminal domains of LIN-14 are dispensable and that a carboxy-terminal region within exons 9 to 13 is necessary and sufficient for in vivo LIN-14 function. A transgene capable of expressing only one of the three alternativelin-14 gene products rescues a lin-14 null mutation and is developmentally regulated by lin-4. This shows ...


Emissions Of Formaldehyde, Acetic Acid, Methanol, And Other Trace Gases From Biomass Fires In North Carolina Measured By Airborne Fourier Transform Infrared Spectroscopy, Robert J. Yokelson, Jon G. Goode, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, D. D. Wade, Issac T. Bertschi, David W. T. Griffith, Wei Min Hao Dec 1999

Emissions Of Formaldehyde, Acetic Acid, Methanol, And Other Trace Gases From Biomass Fires In North Carolina Measured By Airborne Fourier Transform Infrared Spectroscopy, Robert J. Yokelson, Jon G. Goode, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, D. D. Wade, Issac T. Bertschi, David W. T. Griffith, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a “flow-through” multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFTIR spectra acquired within ...


Biochemical And Biophysical Analysis Of The Intracellular Lipid Binding Proteins Of Adipocytes, Melanie A. Simpson, Vince J. Licata, Natalie Ribarik Coe, David A. Bernlohr Dec 1999

Biochemical And Biophysical Analysis Of The Intracellular Lipid Binding Proteins Of Adipocytes, Melanie A. Simpson, Vince J. Licata, Natalie Ribarik Coe, David A. Bernlohr

Biochemistry -- Faculty Publications

Adipocytes express two lipid-binding proteins; the major one termed the adipocyte lipid-binding protein or aP2 (ALBP/aP2) and a minor one referred to as the keratinocyte lipid-binding protein (KLBP). In order to evaluate the potential physiological roles for these proteins, their biochemical and biophysical properties have been analyzed and compared. ALBP/aP2 and KLBP exhibit similar binding affinities for most long-chain fatty acids; however, ALBP/aP2 exhibits a two to three-fold increased affi nity for myristic, palmitic, oleic and linoleic acids, the predominant fatty acids of adipocytes. As measured by guanidinium hydrochloride denaturation, the stability of ALBP/aP2 is nearly ...


Three-Dimensional Structure Of The Gly121tyr Dimeric Form Of Ornithine Decarboxylase From Lactobacillus 30a, Jacqueline Vitali, Donald Carroll, Rochika G. Chaudhrya, Marvin L. Hackert Dec 1999

Three-Dimensional Structure Of The Gly121tyr Dimeric Form Of Ornithine Decarboxylase From Lactobacillus 30a, Jacqueline Vitali, Donald Carroll, Rochika G. Chaudhrya, Marvin L. Hackert

Physics Faculty Publications

Ornithine decarboxylases catalyze the conversion of ornithine to putrescine at the beginning of the polyamine pathway. Ornithine decarboxylase (ODC) from Lactobacillus 30a is a 990612 Da dodecamer composed of six homodimers. A single point mutation (Gly121Tyr) was found to prevent association of dimers into dodecamers. The dimeric protein has been crystallized at pH 7.0 in the presence of guanosine triphosphate (GTP). Crystals belong to space group P3221, with unit-cell parameters a = 111.8, c = 135.9 Å and one monomer in the asymmetric unit. The structure was determined by molecular replacement and refined using simulated annealing ...


Melanoma Chondroitin Sulphate Proteoglycan Regulates Cell Spreading Through Cdc42, Ack-1 And P130Cas, Kathryn M. Eisenmann, James B. Mccarthy, Melanie A. Simpson, Patricia J. Keely, Jun-Lin Guan, Kouichi Tachibana, Louis Lim, Ed Manser, Leo T. Furcht, Joji Iida Dec 1999

Melanoma Chondroitin Sulphate Proteoglycan Regulates Cell Spreading Through Cdc42, Ack-1 And P130Cas, Kathryn M. Eisenmann, James B. Mccarthy, Melanie A. Simpson, Patricia J. Keely, Jun-Lin Guan, Kouichi Tachibana, Louis Lim, Ed Manser, Leo T. Furcht, Joji Iida

Biochemistry -- Faculty Publications

Melanoma chondroitin sulphate proteoglycan (MCSP) is a cell-surface antigen that has been implicated in the growth and invasion of melanoma tumors. Although this antigen is expressed early in melanoma progression, its biological function is unknown. MCSP can stimulate the integrin-α4β1-mediated adhesion and spreading of melanoma cells. Here we show that stimulated MCSP recruits tyrosine- phosphorylated p130cas, an adaptor protein important in tumor cell motility and invasion. MCSP stimulation also results in a pronounced activation and recruitment of the Rho-family GTPase Cdc42. MCSP-induced spreading of melanoma cells is dependent upon active Cdc42, a Cdc42-associated tyrosine kinase (Ack-1) and tyrosine phosphorylation of ...


New Mammalian Selenocysteine-Containing Proteins Identified With An Algorithm That Searches For Selenocysteine Insertion Sequence Elements, Gregory V. Kryukov, Valentin M. Kryukov, Vadim N. Gladyshev Nov 1999

New Mammalian Selenocysteine-Containing Proteins Identified With An Algorithm That Searches For Selenocysteine Insertion Sequence Elements, Gregory V. Kryukov, Valentin M. Kryukov, Vadim N. Gladyshev

Vadim Gladyshev Publications

Mammalian selenium-containing proteins identified thus far contain selenium in the form of a selenocysteine residue encoded by UGA. These proteins lack common amino acid sequence motifs, but 3’-untranslated regions of selenoprotein genes contain a common stem-loop structure, selenocysteine insertion sequence (SECIS) element, that is necessary for decoding UGA as selenocysteine rather than a stop signal. We describe here a computer program, SECISearch, that identifies mammalian selenoprotein genes by recognizing SECIS elements on the basis of their primary and secondary structures and free energy requirements. When SECISearch was applied to search human dbEST, two new mammalian selenoproteins, designated SelT and ...


Sec34p, A Protein Required For Vesicle Tethering To The Yeast Golgi Apparatus, Is In A Complex With Sec35p, Susan M. Vanrheenen, Xiaochun Cao, Stephanie K. Sapperstein, Elbert C. Chiang, Vladimir V. Lupashin, Charles Barlowe, M. Gerard Waters Nov 1999

Sec34p, A Protein Required For Vesicle Tethering To The Yeast Golgi Apparatus, Is In A Complex With Sec35p, Susan M. Vanrheenen, Xiaochun Cao, Stephanie K. Sapperstein, Elbert C. Chiang, Vladimir V. Lupashin, Charles Barlowe, M. Gerard Waters

Open Dartmouth: Faculty Open Access Articles

A screen for mutants of Saccharomyces cerevisiae secretory pathway components previously yielded sec34, a mutant that accumulates numerous vesicles and fails to transport proteins from the ER to the Golgi complex at the restrictive temperature (Wuestehube, L.J., R. Duden, A. Eun, S. Hamamoto, P. Korn, R. Ram, and R. Schekman. 1996. Genetics. 142:393–406). We find that SEC34 encodes a novel protein of 93-kD, peripherally associated with membranes. The temperature-sensitive phenotype of sec34-2 is suppressed by the rab GTPase Ypt1p that functions early in the secretory pathway, or by the dominant form of the ER to Golgi complex ...


Method And Apparatus For Controlling Acoustic Signal Bandwidth In An Ultrasonic Diagnostic Imaging System, Jeffrey R. Resnick, Gregory R. Bashford Nov 1999

Method And Apparatus For Controlling Acoustic Signal Bandwidth In An Ultrasonic Diagnostic Imaging System, Jeffrey R. Resnick, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

An ultrasonic imaging system includes a receive beam former that generates analog receive signals and a scan converter. A receive signal processing path interconnects the receive beamformer and the scan converter, and this processing path includes both an A/D converter characterized by a selectable sampling rate and at least one filter characterized by at least one filter parameter. The filter parameter is selected as a function of the sampling rate to provide enhanced image quality.


An Insulator Element And Condensed Chromatin Region Separate The Chicken Β-Globin Locus From An Independently Regulated Erythroid-Specific Folate Receptor Gene, Marie-Noelle Prioleau, Pascale Nony, Melanie A. Simpson, Gary Felsenfeld Oct 1999

An Insulator Element And Condensed Chromatin Region Separate The Chicken Β-Globin Locus From An Independently Regulated Erythroid-Specific Folate Receptor Gene, Marie-Noelle Prioleau, Pascale Nony, Melanie A. Simpson, Gary Felsenfeld

Biochemistry -- Faculty Publications

We have identified a folate receptor gene upstream of the chicken β-globin locus and separated from it by a 16 kbp region of silent chromatin. We find that this receptor is expressed only at a stage of erythroid differentiation (CFU-E) preceding the activation of β-globin genes, consistent with the role of folate receptors in proliferation. This discovery raises the question of how these two loci are regulated during erythropoiesis. Our data suggest that the folate receptor gene and the β-globin locus are regulated independently. We show that a 3.3 kbp DNA region upstream of the folate receptor gene is ...


A Defect In Interleukin 12-Induced Activation And Interferon Gamma Secretion Of Peripheral Natural Killer T Cells In Nonobese Diabetic Mice Suggests New Pathogenic Mechanisms For Insulin-Dependent Diabetes Mellitus., Marika Falcone, Brian Yeung, Lee Tucker, Enrique Rodriguez, Nora Sarvetnick Oct 1999

A Defect In Interleukin 12-Induced Activation And Interferon Gamma Secretion Of Peripheral Natural Killer T Cells In Nonobese Diabetic Mice Suggests New Pathogenic Mechanisms For Insulin-Dependent Diabetes Mellitus., Marika Falcone, Brian Yeung, Lee Tucker, Enrique Rodriguez, Nora Sarvetnick

Journal Articles: Regenerative Medicine

The function of natural killer T (NKT) cells in the immune system has yet to be determined. There is some evidence that their defect is associated with autoimmunity, but it is still unclear how they play a role in regulating the pathogenesis of T cell-mediated autoimmune diseases. It was originally proposed that NKT cells could control autoimmunity by shifting the cytokine profile of autoimmune T cells toward a protective T helper 2 cell (Th2) type. However, it is now clear that the major function of NKT cells in the immune system is not related to their interleukin (IL)-4 secretion ...


Trace Gas Emissions From Laboratory Biomass Fires Measured By Open-Path Fourier Transform Infrared Spectroscopy: Fires In Grass And Surface Fuels, Jon G. Goode, Robert J. Yokelson, Ronald A. Susott, Darold E. Ward Sep 1999

Trace Gas Emissions From Laboratory Biomass Fires Measured By Open-Path Fourier Transform Infrared Spectroscopy: Fires In Grass And Surface Fuels, Jon G. Goode, Robert J. Yokelson, Ronald A. Susott, Darold E. Ward

Chemistry and Biochemistry Faculty Publications

The trace gas emissions from six biomass fires, including three grass fires, were measured using a Fourier transform infrared (FTIR) spectrometer coupled to an open-path, multipass cell (OP-FTIR). The quantified emissions consisted of carbon dioxide, nitric oxide, water vapor, carbon monoxide, methane, ammonia, ethylene, acetylene, isobutene, methanol, acetic acid, formic acid, formaldehyde, and hydroxyacetaldehyde. By including grass fires in this study we have now measured smoke composition from fires in each major vegetation class. The emission ratios of the oxygenated compounds, formaldehyde, methanol, and acetic acid, were 1–2% of CO in the grass fires, similar to our other laboratory ...


Micromagnetics Simulation Of Nanoshaped Iron Elements: Comparison With Experiment, Ngocnga Dao, S. R. Homer, Scott L. Whittenburg Sep 1999

Micromagnetics Simulation Of Nanoshaped Iron Elements: Comparison With Experiment, Ngocnga Dao, S. R. Homer, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

A micromagnetics simulation has been conducted on nanostructured magnetic elements of iron in order to investigate the effect of the shape of the element on magnetic properties, such as domain formation and hysteresis loops. These results are compared with recent experimental studies. The results display an impressive agreement with both the experimentally observed magnetic domains in individual particles as well as the shape of the hysteresis loops. The simulation results then explain features in the hysteresis loops in terms of vortice formation and motion.


Fish Skeletal Muscle:Adenoisine Triphosphate And Adenine Nucleotide Metabolites In Relation To The Texture And Quality Of Fish, Carmel Wills Sep 1999

Fish Skeletal Muscle:Adenoisine Triphosphate And Adenine Nucleotide Metabolites In Relation To The Texture And Quality Of Fish, Carmel Wills

Doctoral

The changes which occurred in the concentrations of ATP, ADP, AMP, inosine monophosphate, inosine and hypoxanthine in skeletal muscle of rainbow trout, salmon and goldfish during the onset and resolution of rigor mortis were investigated. The effects of ante mortem handling and methods of slaughter on the concentrations of these nucleotides in muscle immediately after death and during storage of fish at 3° and at -30° were examined. Very careful handling of fish and killing by a method which did not cause contraction of muscle were essential if concentrations of ATP were to be at levels indicative of resting muscle ...


Redox Regulation Of Cell Signaling By Selenocysteine In Mammalian Thioredoxin Reductases, Qi-An Sun, Yalin Wu, Francesca Zappacosta, Kuan-Teh Jeang, Byeong Jae Lee, Dolph L. Hatfield, Vadim N. Gladyshev Aug 1999

Redox Regulation Of Cell Signaling By Selenocysteine In Mammalian Thioredoxin Reductases, Qi-An Sun, Yalin Wu, Francesca Zappacosta, Kuan-Teh Jeang, Byeong Jae Lee, Dolph L. Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

The intracellular generation of reactive oxygen species, together with the thioredoxin and glutathione systems, is thought to participate in redox signaling in mammalian cells. The activity of thioredoxin is dependent on the redox status of thioredoxin reductase (TR), the activity of which in turn is dependent on a selenocysteine residue. Two mammalian TR isozymes (TR2 and TR3), in addition to that previously characterized (TR1), have now been identified in humans and mice. All three TR isozymes contain a selenocysteine residue that is located in the penultimate position at the carboxyl terminus and which is encoded by a UGA codon. The ...


Exploring Ground-State Heterogeneity Of Hypericin And Hypocrellin A And B:  Dynamic And 2d Roesy Nmr Study, Alexandre V. Smirnov, D. Bruce Fulton, Amy H. Andreotti, Jacob W. Petrich Aug 1999

Exploring Ground-State Heterogeneity Of Hypericin And Hypocrellin A And B:  Dynamic And 2d Roesy Nmr Study, Alexandre V. Smirnov, D. Bruce Fulton, Amy H. Andreotti, Jacob W. Petrich

Chemistry Publications

A NMR study was conducted on the antiviral and antitumor agents hypericin and hypocrellin A and B, whose activity is light induced. Elucidation of the conformational/tautomeric properties of these polycyclic quinones is important for interpreting their photophysical behavior in the excited state. Evidence for interconversion between ground-state tautomers or other conformational isomers was sought in temperature-dependent 1H NMR and 2D-ROESY studies. For hypericin and hypocrellin B, only one ground-state species is observed. For hypocrellin A, however, three species are significantly populated in the ground state due to the high flexibility of its 7-membered ring. In the latter case dynamic ...


Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond Aug 1999

Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

Vibrational sum frequency spectroscopy has been used in conjunction with dynamic surface tension measurements to study formation of a 1,2-dilauroyl-sn-phosphatidylcholine (DLPC) monolayer at a water–carbon tetrachloride interface. Surface tension measurements show that an aqueous solution of liquid crystalline phosphocholine vesicles (4.5 μM DLPC) requires several hours to form a tightly packed, fully equilibrated monolayer of DLPC monomers. Vibrational spectra of the interfacial region at different stages in the monolayer formation process indicate that the solvent structure undergoes dramatic re-organization as the monolayer forms. Initial adsorption of DLPC monomers severely disrupts the interfacial hydrogen bonding. Intensity ...


Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey Aug 1999

Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OEAS Faculty Publications

The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye-stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected ...


Posttranscriptional Regulation Of Mammalian Methionine Synthase By B12, Sumedha Gulati, Lawrence C. Brody, Ruma V. Banerjee Jul 1999

Posttranscriptional Regulation Of Mammalian Methionine Synthase By B12, Sumedha Gulati, Lawrence C. Brody, Ruma V. Banerjee

Biochemistry -- Faculty Publications

Methionine synthase is one of two key enzymes involved in the removal of the metabolite, homocysteine. Elevated homocysteine levels constitute a risk factor for cardiovascular diseases and for neural tube defects. In cell culture, the activity of methionine synthase is enhanced several-fold by supplementation with its cofactor, B12. The mechanism of this regulation is unknown, although it has been ascribed to a shift from apoenzyme to holoenzyme. Using sensitive assay techniques as well as a combination of Northern and Western analyses, we demonstrate that the effect of B,, on induction of methionine synthase activity is paralleled by an increase ...


Optimal Replication Activity Of Vesicular Stomatitis Virus Rna Polymerase Requires Phosphorylation Of A Residue(S) At Carboxy-Terminal Domain Ii Of Its Accessory Subunit, Phosphoprotein P, Leroy N. Hwang, Nathan Englund, Tapas Das, Amiya K. Florida, Asit K. Pattnaik Jul 1999

Optimal Replication Activity Of Vesicular Stomatitis Virus Rna Polymerase Requires Phosphorylation Of A Residue(S) At Carboxy-Terminal Domain Ii Of Its Accessory Subunit, Phosphoprotein P, Leroy N. Hwang, Nathan Englund, Tapas Das, Amiya K. Florida, Asit K. Pattnaik

Papers in Veterinary and Biomedical Science

The phosphoprotein, P, of vesicular stomatitis virus (VSV) is a key subunit of the viral RNA-dependent RNA polymerase complex. The protein is phosphorylated at multiple sites in two different domains. We recently showed that specific serine and threonine residues within the amino-terminal acidic domain I of P protein must be phosphorylated for in vivo transcription activity, but not for replication activity, of the polymerase complex. To examine the role of phosphorylation of the carboxy-terminal domain II residues of the P protein in transcription and replication, we have used a panel of mutant P proteins in which the phosphate acceptor sites ...


Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung Jul 1999

Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung

OEAS Theses and Dissertations

The present method for the determination of new production (NP) by measuring the uptake of added 15NO3 suffers from a number of limitations. In an attempt to improve this situation, this research examined the possibility of estimating 15NO3– uptake by measuring the activity of nitrate reductase (NRA). In addition, because it has long been suspected that the biological reduction of IO3 to I may be mediated by nitrate reductase (NR), this research investigated the ability of NR to catalyze the reduction of iodate to iodide.

An improved method for the determination of NRA was developed ...


Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen Jul 1999

Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen

Theses and Dissertations in Biomedical Sciences

Using JEG-3 cells as an in vitro model, I investigated the mechanisms behind the tissue-specific expression and steroid hormone regulation of the hGnRH gene in the human placenta. The hGnRH upstream promoter was found to be functionally active in JEG-3 cells. The DNA sequence responsible for functioning of the upstream promoter in JEG-3 cells is narrowed to a region between –1048 bp and –730 bp. This DNA fragment contains four elements, which can bind with nuclear extract from JEG-3 cells (but not from GT1-7 cells).

Estradiol (E2) represses the hGnRH upstream promoter activity in JEG-3 cells. This inhibition is receptor-mediated ...


Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof. Jun 1999

Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The objective of this study was the research of novel and inexpensive sources of polysaccharides degrading enzymes such as amylases and glucanases from local plants in order to justify their biotechnological applications. The isolation of two l3-amylases and an endo-1,3-ß-D-glucanase was reached using common protein purification methods such as buffer extraction, ammonium sulfate fractionation, ionexchange and gel filtration chromatographies. The methods used were simple and easily reproducible, suggesting the possibilfty of large-scale production. ln the crude extract of Curculigo pilosa tuber, only ß-amylase was detected as starch degrading enzyme and its activity was approximately 282 Uig of fresh material ...


Activated Mono-, Di-, And Polysaccharides Reaction Products Thereof, Their Preparation And Uses, John F. Robyt, Rupendra Mukerjea May 1999

Activated Mono-, Di-, And Polysaccharides Reaction Products Thereof, Their Preparation And Uses, John F. Robyt, Rupendra Mukerjea

Iowa State University Patents

Reaction at the interface of an organic solution containing an acidic reactant and an aqueous alkaline solution containing nonreducing carbohydrates such as sucrose, sugar alcohols, cyclodextrins, and polysaccharides imparts a specificity to the reaction for one or more of the primary alcohol groups of the carbohydrate reactant. The resulting activated, nonreducing carbohydrate intermediate can then be converted to a series of substantially pure, low molecular weight reaction products, including a sucrose trimer and dianhydrosucrose, and to a series of substantially pure, higher molecular weight reaction products, including 6-O-sucro cyclodextrins and poly-6-O-sucro amylose.


Cbfa2 Is Required For The Formation Of Intra-Aortic Hematopoietic Clusters, Trista North, Ting-Lei Gu, Stacy Terryl, Qing Wang, Louisa Howard, Michael Binder, Miguel Marín-Padilla, Nancy A. Speck May 1999

Cbfa2 Is Required For The Formation Of Intra-Aortic Hematopoietic Clusters, Trista North, Ting-Lei Gu, Stacy Terryl, Qing Wang, Louisa Howard, Michael Binder, Miguel Marín-Padilla, Nancy A. Speck

Open Dartmouth: Faculty Open Access Articles

Cbfa2 (AML1) encodes the DNA-binding subunit of a transcription factor in the small family of core-binding factors (CBFs). Cbfa2 is required for the differentiation of all definitive hematopoietic cells, but not for primitive erythropoiesis. Here we show that Cbfa2 is expressed in definitive hematopoietic progenitor cells, and in endothelial cells in sites from which these hematopoietic cells are thought to emerge. Endothelial cells expressing Cbfa2 are in the yolk sac, the vitelline and umbilical arteries, and in the ventral aspect of the dorsal aorta in the aorta/genital ridge/mesonephros (AGM) region. Endothelial cells lining the dorsal aspect of the ...


The Mean Spherical Approximation For A Dipolar Yukawa Fluid, Douglas Henderson, Dezso Boda, Istvan Szalai, Kwong-Yu Chan May 1999

The Mean Spherical Approximation For A Dipolar Yukawa Fluid, Douglas Henderson, Dezso Boda, Istvan Szalai, Kwong-Yu Chan

All Faculty Publications

The dipolar hard sphere fluid (DHSF) is a useful model of a polar fluid. However, the DHSF lacks a vapor–liquid transition due to the formation of chain-like structures. Such chains are not characteristic of real polar fluids. A more realistic model of a polar fluid is obtained by adding a Lennard–Jones potential to the intermolecular potential. Very similar results are obtained by adding a Yukawa potential, instead of the Lennard–Jones potential. We call this fluid the dipolar Yukawa fluid (DYF). We show that an analytical solution of the mean spherical approximation (MSA) can be obtained for the ...


Reductive Dehydroxy Coupling Of 2-(Hydroxymethyl)Indenes To Prepare Ethano-Bridged Bis(2-Indenyl) Ansa-Titanocenes, Hasan Palandoken, Justin K. Wyatt, Shawn R. Hitchcock, Marilyn M. Olmstead, Michael H. Nantz May 1999

Reductive Dehydroxy Coupling Of 2-(Hydroxymethyl)Indenes To Prepare Ethano-Bridged Bis(2-Indenyl) Ansa-Titanocenes, Hasan Palandoken, Justin K. Wyatt, Shawn R. Hitchcock, Marilyn M. Olmstead, Michael H. Nantz

Chemistry and Biochemistry

New examples of ansa-titanocenes derived from 1,2-bis(2-indenyl)ethane have been prepared. The titanium-mediated reductive coupling of 2-(hydroxymethyl)indenes provided a convenient method for substrate dimerization. Alkyl substitution of the indene ring at C(3) improved the regioselectivity of the reductive coupling to provide the ethylene bis(2-indenyl)ansa-ligands in 29–62% yield.


A Role For The Light-Dependent Phosphorylation Of Visual Arrestin, Paul G. Alloway, Patrick J. Dolph May 1999

A Role For The Light-Dependent Phosphorylation Of Visual Arrestin, Paul G. Alloway, Patrick J. Dolph

Open Dartmouth: Faculty Open Access Articles

Arrestins are regulatory proteins that participate in the termination of G protein-mediated signal transduction. The major arrestin in the Drosophila visual system, Arrestin 2 (Arr2), is phosphorylated in a light-dependent manner by a Ca2+/calmodulin-dependent protein kinase and has been shown to be essential for the termination of the visual signaling cascade in vivo. Here, we report the isolation of nine alleles of the Drosophila photoreceptor cell-specific arr2 gene. Flies carrying each of these alleles underwent light-dependent retinal degeneration and displayed electrophysiological defects typical of previously identified arrestin mutants, including an allele encoding a protein that lacks the major Ca2 ...


Design Of A Low Power Two-Channel Biotelemetry Transmitter And Demodulator For Use In Studies Of Sleep Behavior In Birds, Charles Amlaner, Brent Carr, Denis Curtis, Samuel Mcgarrah, Derek Sunderman Apr 1999

Design Of A Low Power Two-Channel Biotelemetry Transmitter And Demodulator For Use In Studies Of Sleep Behavior In Birds, Charles Amlaner, Brent Carr, Denis Curtis, Samuel Mcgarrah, Derek Sunderman

Charles J. Amlaner

Current technology in biomedical engineering has made it possible to remotely transmit, demodulate, store and accurately display a large suite of physiological electrical signals. By carefully selecting modern CMOS circuitry, the designer can fabricate micro-miniature, low power systems that ultimately can be hermetically sealed and implanted in a live, free-ranging animal. It was the lack of miniature, low power transmitter circuitry that has hampered some of the basic research questions on sleep patterns in free ranging animals, particularly birds and other small animals. We formulated a team of engineers in our Animal Sleep Research Laboratory to identify the critical technical ...


Secondary Metabolites From Montana Isolates Of Penicillium, Jennifer Hill Apr 1999

Secondary Metabolites From Montana Isolates Of Penicillium, Jennifer Hill

Chemistry and Physics Undergraduate Theses

Extracellular and intracellular secondary metabolites were extracted from w different cultures of Penicillium, isolated mostly from rust galls on lodgepole and ponderosa pine in Montana. Extracts containing the fungal metabolites were applied to silica-gel thin layer chromatography strips by blotting agar plugs from mycelial cultures. Chromatograms were developed with appropriate solvents in chromatography chambers. The chromatograms were then viewed under normal light and ultraviolet light at wavelengths of 254 nm and 366 nm. Standard literature was used to identify the metabolites. Results show that new metabolites as well as some previously reported metabolites are produced by these Montana Penicillium isolates.


Western Blotting And Amido Black Characterization Of The Glycoprotein Nature Of A Melanoplus Differentialis Lectin: Gha, Kirsten Rindal Apr 1999

Western Blotting And Amido Black Characterization Of The Glycoprotein Nature Of A Melanoplus Differentialis Lectin: Gha, Kirsten Rindal

Life and Environmental Sciences Undergraduate Theses

The carbohydrate nature ofthe lectin GHA was studied using Western Blotting (Concanavalin A as a carbohydrate indicator) coupled with Amido Black staining (as a protein indicator). GHA is composed of two molecules: GHA la and GHA lb used in Western Blotting and Amido Black staining. In the presence of Concanavalin A, non-deglycosylated GHA la and lb produce bands. Upon cleavage by PNGase F, GHA la and lb show an Amido Black band and the absence of a Concanavalin A-sensitive band. These results show GHA to be an N-linked glycoprotein whose carbohydrate has a mass of ~ 2500 Da (~10 hexose units ...