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1993

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Articles 1 - 30 of 79

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

A Characterization Of Extractable, Hydroxylated Fatty Acid Bearing Components In Legionella Pneumophila, Jonathan R. Lane Dec 1993

A Characterization Of Extractable, Hydroxylated Fatty Acid Bearing Components In Legionella Pneumophila, Jonathan R. Lane

Electronic Theses and Dissertations

Extraction of the lipids of Legionella pneumophila yields phases unlike those produced from other Gram-negative bacteria. A viscous interface forms between the aqueous (wash) and organic phases. More than half of the hydroxylated fatty acids were found distributed between the aqueous phase and the interfacial material, fractions in which such constituents have not been reported in other Gram-negative species. It was further observed that after the material from the aqueous/interfacial phase was dissolved in methanol or chloroform/methanol (2:1 (V/V)), the addition of acetone would create a white, flocculent precipitate. Analyses showed that the supernatant contained fatty ...


Unusual Structure Of A Human Middle Repetitive Dna, Duminda D. Ratnasinghe Dec 1993

Unusual Structure Of A Human Middle Repetitive Dna, Duminda D. Ratnasinghe

Electronic Theses and Dissertations

The L2Hs sequences are a polymorphic, interspersed, middle repetitive DNA family unique to human genomes. Genomic fingerprinting indicates that these DNAs vary from one individual to another and between tissues of the same individual. Sequence analysis reveals that they are AT-rich (76%) and contain many unusual sequence arrangements (palindromes, inverted and direct repeats). These sequence properties confer on the L2Hs elements the potential to fold into non-B-form structures, a characteristic of recombination hot spots. To test this hypothesis carbodiimide, osmium tetroxide and S$\sb1$ nuclease were used as single-strand specific probes to study a recombinant plasmid, pN6.4.39, containing ...


Severe Bone Marrow Suppression In A Patient With Rheumatoid Arthritis On Methotrexate, M P. Iqbal, A A. Ali, A A. Alvi Dec 1993

Severe Bone Marrow Suppression In A Patient With Rheumatoid Arthritis On Methotrexate, M P. Iqbal, A A. Ali, A A. Alvi

Department of Biological & Biomedical Sciences

No abstract provided.


A Molecular Basis For Erythromycin Sensitivity And Resistance In Escherichia Coli, Harold S. Chittum Dec 1993

A Molecular Basis For Erythromycin Sensitivity And Resistance In Escherichia Coli, Harold S. Chittum

Electronic Theses and Dissertations

The effect of erythromycin on the 50S ribosomal subunit during cell growth has been extensively investigated. Sucrose density gradient analysis of ribosomes formed in the presence and absence of the drug revealed a 50S specific assembly defect is partially responsible for erythromycin's inhibitory effects on wild type cells. Examination of two erythromycin-resistant mutants of E. coli (N281 and N282) revealed that mutant N281 (L22 mutant) but not N282 (L4 mutant) was assembly defective in the presence of the drug, although only at much higher drug concentrations (300 ug/ml vs. 75 ug/ml for wild type cells). The altered ...


Gtp Hydrolysis By Complexes Of The Signal Recognition Particle And The Signal Recognition Particle Receptor, Timothy Connolly, Reid Gilmore Nov 1993

Gtp Hydrolysis By Complexes Of The Signal Recognition Particle And The Signal Recognition Particle Receptor, Timothy Connolly, Reid Gilmore

Open Access Articles

Translocation of proteins across the endoplasmic reticulum membrane is a GTP-dependent process. The signal recognition particle (SRP) and the SRP receptor both contain subunits with GTP binding domains. One GTP-dependent reaction during protein translocation is the SRP receptor-mediated dissociation of SRP from the signal sequence of a nascent polypeptide. Here, we have assayed the SRP and the SRP receptor for GTP binding and hydrolysis activities. GTP hydrolysis by SRP was not detected, so the maximal GTP hydrolysis rate for SRP was estimated to be < 0.002 mol GTP hydrolyzed x mol of SRP-1 x min-1. The intrinsic GTP hydrolysis activity of the SRP receptor ranged between 0.02 and 0.04 mol GTP hydrolyzed x mol of SRP receptor-1 x min-1. A 40-fold enhancement of GTP hydrolysis activity relative to that observed for the SRP receptor alone was obtained when complexes were formed between SRP and the SRP receptor. GTP hydrolysis activity was inhibited by GDP, but not by ATP. Extended incubation of the SRP or the SRP receptor with GTP resulted in substoichiometric quantities of protein-bound ribonucleotide. SRP-SRP receptor complexes engaged in GTP hydrolysis were found to contain a minimum of one bound guanine ribonucleotide per SRP-SRP receptor complex. We conclude that the GTP hydrolysis activity described here is indicative of one of the GTPase cycles that occur during protein translocation across the endoplasmic reticulum.


Thermodynamics Of Single-Stranded Rna And Dna Interactions With Oligolysines Containing Tryptophan. Effects Of Base Composition., David Mascotti, Timothy Lohman Oct 1993

Thermodynamics Of Single-Stranded Rna And Dna Interactions With Oligolysines Containing Tryptophan. Effects Of Base Composition., David Mascotti, Timothy Lohman

David P. Mascotti

No abstract provided.


Redistribution Of Clathrin-Coated Vesicle Adaptor Complexes During Adipocytic Differentiation Of 3t3-L1 Cells, Ranjan Chakrabarti, Marguerite Joly, Silvia Corvera Oct 1993

Redistribution Of Clathrin-Coated Vesicle Adaptor Complexes During Adipocytic Differentiation Of 3t3-L1 Cells, Ranjan Chakrabarti, Marguerite Joly, Silvia Corvera

Open Access Articles

Mechanisms for intracellular retention of proteins are induced during adipocytic differentiation of 3T3-L1 cells. To investigate the potential role of clathrin lattices in these retention processes, we performed a morphological and biochemical analysis of coated vesicle components in 3T3-L1 cells. Optical sectioning and image restoration revealed a marked increase in the staining of clathrin and beta adaptins in the perinuclear region of cells with differentiation. In addition, predominance of beta (subunit of the AP-2, plasma membrane adaptor) over beta' (subunit of the AP-1, Golgi adaptor) adaptin was observed in immunoblots of clathrin-coated vesicles purified from nondifferentiated fibroblasts, and this ratio ...


The 2′-Phosphate Of Nadp Is Critical For Optimum Productive Binding To 6-Phosphogluconate Dehydrogenase From Candida Utilis, Anthony J. Berdis, Paul F. Cook Sep 1993

The 2′-Phosphate Of Nadp Is Critical For Optimum Productive Binding To 6-Phosphogluconate Dehydrogenase From Candida Utilis, Anthony J. Berdis, Paul F. Cook

Chemistry Faculty Publications

Initial velocity studies obtained with alternative dinucleotide substrates for the 6-phosphogluconate dehydrogenase reaction suggest that the 2′-phosphate is critical for the optimum productive binding of the dinucleotide substrate. Initial velocity patterns obtained by varying 6-phosphogluconate at different fixed levels of NAD are nearly parallel with apparent competitive substrate inhibition by 6-phosphogluconate at pH 7 and below but intersect to the left of the ordinate at pH 8 and above. Dead-end inhibition studies indicate that the mechanism is random at all pH values. Data are interpreted in terms of a random mechanism with marked antagonism in the binding of NAD ...


The Primary Structure Of A Fungal Chitin Deacetylase Reveals The Function For Two Bacterial Gene Products., Dimitris Kafetzopoulos, George Thireos, John N. Vournakis, Vassilis Bouriotis Sep 1993

The Primary Structure Of A Fungal Chitin Deacetylase Reveals The Function For Two Bacterial Gene Products., Dimitris Kafetzopoulos, George Thireos, John N. Vournakis, Vassilis Bouriotis

Open Dartmouth: Faculty Open Access Articles

Chitin deacetylase (EC 3.5.1.41) hydrolyzes the N-acetamido groups of N-acetyl-D-glucosamine residues in chitin. A cDNA to the Mucor rouxii mRNA encoding chitin deacetylase was isolated, characterized, and sequenced. Protein sequence comparisons revealed significant similarities of the fungal chitin deacetylase to rhizobial nodB proteins and to an uncharacterized protein encoded by a Bacillus stearothermophilus open reading frame. These data suggest the functional homology of these evolutionarily distant proteins. NodB is a chitooligosaccharide deacetylase essential for the biosynthesis of the bacterial nodulation signals, termed Nod factors. The observed similarity of chitin deacetylase to the B. stearothermophilus gene product suggests ...


Sds Non-Acrylamide Polymeric Gel-Filled Capillary Electrophoresis For Molecular Size Separation Of Protein, Devon Andres Aug 1993

Sds Non-Acrylamide Polymeric Gel-Filled Capillary Electrophoresis For Molecular Size Separation Of Protein, Devon Andres

Honors Theses

Sodium dodecyl sulfide (SDS) non-acrylamide gel-filled capillary columns are a new technology being used for analysis and separation of biotechnology-derived proteins. This research was to compare this new technology to the current methods of SDS polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance size-exclusion chromatography (HPSEC). The molecular mass of four different recombinant proteins were determined by two commercialized SDS non-acrylamide gel-filled capillary columns, SDS-PAGE, and HPSEC. The data obtained showed that the SDS non-acrylamide gel-filled capillary columns were compatible with the SDS-PAGE technique for molecular mass determination. HPSEC was shown to be unreliable for molecular weight determination. SDS non-acrylamide gel-filled capillary ...


Inheritance Of Freezing Resistance In Tuber-Bearing Solanum Species: Evidence For Independent Genetic Control Of Nonacclimated Freezing Tolerance And Cold Acclimation Capacity, Julie M. Stone, Jiwan P. Palta, John B. Bamberg, Laurie S. Weiss, James F. Harbage Aug 1993

Inheritance Of Freezing Resistance In Tuber-Bearing Solanum Species: Evidence For Independent Genetic Control Of Nonacclimated Freezing Tolerance And Cold Acclimation Capacity, Julie M. Stone, Jiwan P. Palta, John B. Bamberg, Laurie S. Weiss, James F. Harbage

Biochemistry -- Faculty Publications

Frost or winter survival is regarded as a complex trait with polygenic inheritance. Two maijor components of this survival in crop plants are freezing tolerance in the nonacclimated state and cold acclimation capacity. To date researchers have not distinguished the two components as separate heritable traits. The mode of inheritance of these two traits was investigated in F1 and backcross populations of two wild diploid potato species (Solanum commersonii and Solanum cardiophyllum) exhibiting extremes of freezing tolerance and acclimation capacity. Precise assessment of these two traits allowed distinction of small but significant differences among genotypes. The two traits were not ...


The Interplay Of Light And The Circadian Clock. Independent Dual Regulation Of Clock-Controlled Gene Ccg-2(Eas), Guiseppina Arpaia, Jennifer J. Loros, Jay C. Dunlap, Giorgio Morelli, Guiseppe Macino Aug 1993

The Interplay Of Light And The Circadian Clock. Independent Dual Regulation Of Clock-Controlled Gene Ccg-2(Eas), Guiseppina Arpaia, Jennifer J. Loros, Jay C. Dunlap, Giorgio Morelli, Guiseppe Macino

Open Dartmouth: Faculty Open Access Articles

Ambient light is the major agent mediating entrainment of circadian rhythms and is also a major factor influencing development and morphogenesis. We show that in Neurospora crassa the expression of clock-controlled gene 2 (ccg-2), a gene under the control of the circadian clock and allelic to the developmental gene easy wettable (eas), is regulated by light in wild-type strains. Light elicits a direct and important physiological effect on ccg-2(eas) expression as demonstrated using several mutant Neurospora strains. In white collar mutants (wc-1 and wc-2) that are “blind” to blue light, ccg-2(eas) mRNA shows no variation following illumination with ...


Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algea And Plants, David Bollivar Jul 1993

Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algea And Plants, David Bollivar

Scholarship

No abstract provided.


Leukocyte Extravasation Into The Pancreatic Tissue In Transgenic Mice Expressing Interleukin 10 In The Islets Of Langerhans., Lise Wogensen, Xiaojian Huang, Nora Sarvetnick Jul 1993

Leukocyte Extravasation Into The Pancreatic Tissue In Transgenic Mice Expressing Interleukin 10 In The Islets Of Langerhans., Lise Wogensen, Xiaojian Huang, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Transgenic expression of interleukin 10 (IL-10) in the islets of Langerhans leads to a pronounced pancreatic inflammation, without inflammation of the islets of Langerhans and without diabetes. A scattered infiltration of macrophages (M pi) precedes localized accumulations of CD4+ and CD8+ T lymphocytes, B lymphocytes, and M pi. This recruitment of inflammatory cells to the pancreas is somewhat surprising, since the biological activities of IL-10 in vitro indicate that IL-10 is a powerful immunosuppressive cytokine. Since endothelial cells play a major role in leukocyte extravasation, we examined if vascular changes and extralymphoid induction of peripheral and mucosal type vascular addressins ...


Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet C. Mandon, Alex Hausler, Kelley W. Moremen, Carlos B. Hirschberg, Phillips W. Robbins Jul 1993

Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet C. Mandon, Alex Hausler, Kelley W. Moremen, Carlos B. Hirschberg, Phillips W. Robbins

Open Access Articles

Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn ...


Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algae And Plants, David Bollivar, Carl E. Bauer, Jon Y. Suzuki Jun 1993

Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algae And Plants, David Bollivar, Carl E. Bauer, Jon Y. Suzuki

David Bollivar

A wide variety of macrocyclic tetrapyrrole compounds are synthesized by cells for use in diverse cellular processes. As shown in Fig. 1, this pathway includes the synthesis of closed tetrapyrrole compounds that contain metals, such as cobalt-containing cobalamin (vitamin B12), nickel-containing methanogenesis coenzyme F430, copper-containing pigment turacin, iron-containing heme and siroheme, and magnesium-containing chlorophylls and bacteriochlorophylls. Also synthesized by this pathway are a variety of open macrocyclic compounds such as the family of bilins that are used as a source of light-harvesting pigments in cyanobacteria, red algae, and cryptophytes as well as the chromophore that is covalently attached to phytochrome ...


Human Lung Mast Cell Tryptase Isozymes: Separation And Examination Of Structural And Functional Differences, Susan S. Little May 1993

Human Lung Mast Cell Tryptase Isozymes: Separation And Examination Of Structural And Functional Differences, Susan S. Little

Electronic Theses and Dissertations

Tryptases are trypsin-like enzymes found in mast cell granules. Although in vivo substrates have not been positively identified, tryptases cleave a limited number of potential physiological substrates in vitro, including high molecular weight kininogen (HMWK) and vasoactive intestinal peptide (VIP). Purified human lung mast cell tryptase (HLT) apparently exists as a tetramer with an M$\sb{\rm r}$ of 135-144 kDa by gel filtration, whereas SDS-PAGE yielded two bands of M$\sb{\rm r}$ 29 Kda and 33 Kda. Tryptases are resistant to inhibition by most natural trypsin inhibitors and display some affinity for heparin. The existence of tryptase isozymes ...


Probing Protein-Protein Interactions Among Proteins Of A Nonaggregated Fatty Acid Synthetase From Euglena Gracilis Variety Bacillaris, Sande G. Williams May 1993

Probing Protein-Protein Interactions Among Proteins Of A Nonaggregated Fatty Acid Synthetase From Euglena Gracilis Variety Bacillaris, Sande G. Williams

Electronic Theses and Dissertations

Enoyl-acyl carrier protein (ACP) reductase from chloroplast nonaggregated fatty acid synthetase (FAS) of Euglena gracilis variety bacillaris was purified to a single band on a denaturing polyacrylamide gel. The enzyme was partially characterized with respect to substrate specificity, reduced nucleotide requirement, and the effect of ACP and Ca$\sp{++}$ on enzyme activity. Antibodies against the purified protein were raised in hens and isolated from eggs. ACP was purified from Euglena in yields of about 1mg/100g (wet weight) of cells. Antibodies were raised against the purified protein. ACP antibodies inhibited the Euglena chloroplast FAS using Euglena or E. coli ACP ...


Gal4 Disrupts A Repressing Nucleosome During Activation Of Gal1 Transcription In Vivo, Jeffrey D. Axelrod, Michael S. Reagan, John Majors May 1993

Gal4 Disrupts A Repressing Nucleosome During Activation Of Gal1 Transcription In Vivo, Jeffrey D. Axelrod, Michael S. Reagan, John Majors

Biology Faculty Publications

Photofootprinting in vivo of GALl reveals an activation- dependent pattern between the UASG and the TATA box, in a sequence not required for transcriptional activation by GAL4. The pattern results from a nucleosome whose position depends on sequences within the UASG. In the wild-type gene, activation by GAL4 and derivatives disrupts this nucleosome. This activity is independent of interactions with DNA-bound core transcription factors and is proportional to the strength of the activator. Presence of the nucleosome correlates with low basal transcription levels under various conditions, suggesting a role in limiting basal expression. We propose a role for the GAL4 ...


Thrombin-Binding Dna Aptamer Forms A Unimolecular Quadruplex Structure In Solution, James A. Roe, Roman F. Macaya, Peter Schultze, Flint W. Smith, Juli Feigon Apr 1993

Thrombin-Binding Dna Aptamer Forms A Unimolecular Quadruplex Structure In Solution, James A. Roe, Roman F. Macaya, Peter Schultze, Flint W. Smith, Juli Feigon

Chemistry and Biochemistry Faculty Works

We have used two-dimensional 1H NMR spectroscopy to study the conformation of the thrombin-binding aptamer d(GGTTGGTGTGGTTGG) in solution. This is one of a series of thrombin-binding DNA aptamers with a consensus 15-base sequence that was recently isolated and shown to inhibit thrombin-catalyzed fibrin clot formation in vitro [Bock, L. C., Griffin, L. C., Latham, J. A., Vermaas, E. H. & Toole, J. J. (1992) Nature (London) 355, 564-566]. The oligonucleotide forms a unimolecular DNA quadruplex consisting of two G-quartets connected by two TT loops and one TGT loop. A potential T.T bp is formed between the two TT loops ...


Immunomagnetic Selection Of Acrosome-Reacted Bovine Spermatozoa, Thomas Mccormick Apr 1993

Immunomagnetic Selection Of Acrosome-Reacted Bovine Spermatozoa, Thomas Mccormick

Life and Environmental Sciences Undergraduate Theses

The anterior end of the mammalian sperm nucleus is covered by a thin, double-layered membranous sac that contains hydrolytic enzymes including acrosin, hyaluronidase, esterases and acid hydrolases. These enzymes, which are involved in the initial phase of fertilization, are activated and released during the acrosome reaction. This exposure of the acrosomal contents occurs not only during fertilization, but also during sperm death.

Acrosome-reacted sperm cells were selected from thawed, cryopreserved samples of bovine spermatozoa using rabbit antibodies to bovine acrosine and goat anti-rabbit immunoglobulin-coated magnetic beads. The selection process was monitored by staining with fluorescence isothiocynate- beads coupled to anti-rabbit ...


Molecular Cloning Of Pl30 Cdna, Katharine Jurist Apr 1993

Molecular Cloning Of Pl30 Cdna, Katharine Jurist

Life and Environmental Sciences Undergraduate Theses

Acquired pure red cell aplasia (PRCA) is an autoimmune disease characterized by poor red blood cell formation. In no instance has the molecular target of the autoimmunity been identified. In one case, a unique antibody, binding to a membrane protein of 130 kDa (P130) has been shown on immunoblots of mouse erythroleukemia (MEL) cells and other erythroid progenitor cells. Because P130 may be important in red cell development, the cloning and sequencing of its cDNA is of interest.

Initially, I reproduced the detection of this protein with patient antisera using an indirect immunoblotting technique and enhanced chemiluminescence (ECL) detection. Experimenting ...


Regulation Of Δ-Aminolevulinic Acid Synthase And Heme Oxygenase In Cultured Chick Embryo Liver Cells: Synergistic Induction Of Both Enzymes By Glutathimide And Iron And Repression Of Δ-Aminolevulinic Acid Synthase By Metalloporphyrins And Heme: A Dissertation, Edward Earl Cable Apr 1993

Regulation Of Δ-Aminolevulinic Acid Synthase And Heme Oxygenase In Cultured Chick Embryo Liver Cells: Synergistic Induction Of Both Enzymes By Glutathimide And Iron And Repression Of Δ-Aminolevulinic Acid Synthase By Metalloporphyrins And Heme: A Dissertation, Edward Earl Cable

GSBS Dissertations and Theses

Primary chick embryo liver cells were used to explore the regulation of δ-aminolevulinic acid synthase and heme oxygenase, the enzymes that catalyze the rate-limiting reactions of heme anabolism and catabolism, respectively. The general focus of the work was the exploration of the novel observation in which glutethimide and iron synergistically induced both δ-aminolevulinic acid synthase and heme oxygenase, a phenomenon that would not be predicted a priori. The course of events appeared to be: first, that heme synthesis was increased after addition of the glutethimide and that iron potentiated heme synthesis; second, the heme induced heme oxygenase five to ten ...


Apparatus And Method For Transient Thermal Infrared Spectrometry Of Flowable Enclosed Materials, John F. Mcclelland, Roger W. Jones Mar 1993

Apparatus And Method For Transient Thermal Infrared Spectrometry Of Flowable Enclosed Materials, John F. Mcclelland, Roger W. Jones

Iowa State University Patents

A method and apparatus for enabling analysis of a flowable material enclosed in a transport system having an infrared transparent wall portion. A temperature differential is transiently generated between a thin surface layer portion of the material and a lower or deeper portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material, and the altered thermal infrared emission spectrum is detected through the infrared transparent portion of the transport system while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material ...


Hepatic Lipase Treatment Of Chylomicron Remnants Increases Exposure Of Apolipoprotein E, Dawn L. Brasaemle, Kathleen Cornely-Moss, André Bensadoun Mar 1993

Hepatic Lipase Treatment Of Chylomicron Remnants Increases Exposure Of Apolipoprotein E, Dawn L. Brasaemle, Kathleen Cornely-Moss, André Bensadoun

Chemistry Department Faculty Publications

The consequences of hepatic lipase treatment of chylomicron remnants were studied. Rats were fed corn oil to induce production and secretion of chylomicrons and were then injected with polyclonal antiserum raised against hepatic lipase to specifically and quantitatively inhibit hepatic lipase activity in vivo. A fraction enriched in chylomicron remnants was isolated from rat plasma by a brief centrifugation step that preferentially isolates triglyceride-rich apolipoprotein (apo) B-48-containing lipoproteins. The chylomicron remnants were then treated with hepatic lipase in vitro, or incubated under identical conditions in the absence of enzyme (control incubations). Hepatic lipase-treated and control chylomicron remnants were isolated by ...


Investigation Of The Structural Heterogeneity Of Lipooligosaccharides From Pathogenic Haemophilus And Neisseria Species And Of R-Type Lipopolysaccharides From Salmonella Typhimurium By Electrospray Mass Spectrometry, B W. Gibson, William Melaugh, Nancy J. Phillips, M A. Apicella, A A. Campagnari, J M. Griffiss Jan 1993

Investigation Of The Structural Heterogeneity Of Lipooligosaccharides From Pathogenic Haemophilus And Neisseria Species And Of R-Type Lipopolysaccharides From Salmonella Typhimurium By Electrospray Mass Spectrometry, B W. Gibson, William Melaugh, Nancy J. Phillips, M A. Apicella, A A. Campagnari, J M. Griffiss

Chemistry Faculty Publications

Heterogeneity in the lipooligosaccharides (LOS) of pathogenic Haemophilus and Neisseria species is evident from the multiplicity of components observed with electrophoretic analyses. Knowledge of the precise structures that make up these diverse LOS molecules is clearly the key to reaching an understanding of pathogenic processes such as phase variation and molecular mimicry. Except for a few cases, little is known about the specific structural features of LOS that underlie phase variation and molecular mimicry, partly because of the inherent difficulties in the structural elucidation of these complex glycolipids. In the lipopolysaccharides (LPS) from Salmonella typhimurium and Escherichia coli, rough, or ...


Site-Directed Mutagenesis By Double Polymerase Chain Reaction: Megaprimer Method, Sailen Barik Jan 1993

Site-Directed Mutagenesis By Double Polymerase Chain Reaction: Megaprimer Method, Sailen Barik

Biological, Geological, and Environmental Faculty Publications

The "megaprimer" method (1) based on polymerase chain reaction (PCR) is one of the simplest and most versatile procedures of site-specific in vitro mutagenesis available to date. The method utilizes three oligonucleotide primers and two rounds of PCR performed on a DNA template containing the cloned gene that is to be mutated. The rationale of the method is shown schematically in Fig. 1 where A and B represent the "flanking" primers that can map either within the cloned gene or outside the gene (i.e., within the vector sequence) and M represents the internal "mutant" primer containing the desired base ...


Functional Explanation And Metaphysical Individualism, Justin Schwartz Jan 1993

Functional Explanation And Metaphysical Individualism, Justin Schwartz

Justin Schwartz

A number of (present or former) analytical Marxists, such as Jon Elster, have argued that functional explanation has almost no place in the social sciences. (Although the discussion is framed in terms of a debate among analytical Marxists, the point is quite general, and Marxism is used for illustrative purposes.) Functional explanation accounts for what is to be explained by reference to its function; thus, sighted organism have eyes because eyes enable them to see. Elster and other critics of functional explanation argue that this pattern of explanation is inconsistent with "methodological individualism," the idea, as they understand it, that ...


Acute Toxicity Of The Bird Repellent, Methyl Anthranilate, To Fry Of Salmo Salar, Oncorhynus Mykiss, Ictalurus Punctatus And Lepomis Macrochirus, Larry Clark, John Cummings, Steven Bird, Eugeny Aronov Jan 1993

Acute Toxicity Of The Bird Repellent, Methyl Anthranilate, To Fry Of Salmo Salar, Oncorhynus Mykiss, Ictalurus Punctatus And Lepomis Macrochirus, Larry Clark, John Cummings, Steven Bird, Eugeny Aronov

Larry Clark

Several laboratory and field studies have shown methyl anthranilate to be an effective, non-toxic and non-lethal bird repellent, with application potential for protecting crops, seeds, turf and fish stocks from bird damage. Furthermore, methyl anthranilate can be added to liquids for the purposes of protecting nigratory birds, e.g. addition to waste water associated with mining and to standing water pools at airports. Mammalian toxicity data are favorable. Methyl anthranilate is used as a fragrance and food flavoring and is GRAS listed by the US Food and Drug Administration. Despite the favorable outlook for methyl anthranilate's use as a ...


Tailoring The Ph Dependence Of Glucoamylase From Aspergillus Awamori By Mutagenesis , Ufuk Bakir Jan 1993

Tailoring The Ph Dependence Of Glucoamylase From Aspergillus Awamori By Mutagenesis , Ufuk Bakir

Retrospective Theses and Dissertations

A program of cassette mutagenesis was undertaken in the active site of Aspergillus awamori glucoamylase, mainly to alter the effect of pH dependence of the enzyme but also to determine possible functions of the mutated residues. For this purpose, nine single amino acid mutants were prepared and expressed in Saccharomyces cerevisiae, and their effects were determined by using steady-state enzyme kinetics;Three different groups of mutations were designed. In the first group, Glu179 → Asp, Asp176 → Glu, and Glu180 → Asp mutations were prepared. The Glu179 → Asp mutation led to a very large decrease in k[subscript] cat but no change in ...