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Articles 4171 - 4200 of 4357

Full-Text Articles in Molecular Biology

Molecular Cloning Of Cdnas And Genes Coding For Beta-Methylcrotonyl-Coa Carboxylase Of Tomato, Xun Wang, Eve S. Wurtele, Greg Keller, Angela L. Mckean, Basil J. Nikolau Jan 1994

Molecular Cloning Of Cdnas And Genes Coding For Beta-Methylcrotonyl-Coa Carboxylase Of Tomato, Xun Wang, Eve S. Wurtele, Greg Keller, Angela L. Mckean, Basil J. Nikolau

Botany Publication and Papers

Tomato cDNA and genomic clones were isolated by using as a probe a cDNA clone that had originally been identified by its ability to direct the synthesis of a biotin-containing polypeptide in Escherichia coli. The nucleotide sequences of the newly isolated cDNAs indicate that they are clones of a single mRNA molecule. However, one of the cDNA clones contains an insertion of a sequence which we identified as an unspliced intron. The amino acid sequence deduced from the nucleotide sequence of the cDNAs showed similarity to regions of previously sequenced biotin enzymes, indicating that the isolated cDNAs code for a ...


Global Phylogeography Of Yellowfin Tuna, Thunnus Albacares, And Mackerels Of The Genus Scomber, Daniel R. Scoles Jan 1994

Global Phylogeography Of Yellowfin Tuna, Thunnus Albacares, And Mackerels Of The Genus Scomber, Daniel R. Scoles

Dissertations, Theses, and Masters Projects

Intraspecific genetic relationships within yellowfin tuna, Thunnus albacares, and three mackerels of the genus Scomber were studied by restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA). The comparison of these scombrids, with different larval distributions, adult distributions, and vagilities, served to investigate the hypothesis that population structure in marine fishes results from geographic and physical oceanographic processes that limit dispersal of early life history stages. Samples of 20 yellowfin tuna were examined from each of five Pacific locations and one Atlantic location. MtDNA analysis with 12 informative restriction endonucleases demonstrated considerable genetic variation, as evidenced by overall nucleon ...


Oat Phya Containing Transgenic Tobacco: An Examination Of Oat Phya Mrna Stability And The Role Of Oat Phya In Germination Of Tobacco Seed , Linda Joanne Barnes Jan 1994

Oat Phya Containing Transgenic Tobacco: An Examination Of Oat Phya Mrna Stability And The Role Of Oat Phya In Germination Of Tobacco Seed , Linda Joanne Barnes

Retrospective Theses and Dissertations

The regulation of oat phytochrome A (phyA) mRNA stability and the photoregulation of germination of tobacco seeds containing the oat phyA gene was examined using oat phyA containing transgenic tobacco. Oat phyA mRNA has been previously shown to be a relatively unstable mRNA. The intent of this research was to identify elements within the phyA mRNA responsible for rendering the message unstable. The approach taken was to use tobacco transformed with either the full-length or truncated versions of the oat phyA gene and examine the half-lives of the resulting oat phyA mRNAs in transgenic tobacco. RNA blot analysis of oat ...


Soybean Cultivar Development: A Genome Perspective , Lisa Lou Lorenzen Jan 1994

Soybean Cultivar Development: A Genome Perspective , Lisa Lou Lorenzen

Retrospective Theses and Dissertations

The purpose of this dissertation was to retrospectively analyze the process of soybean cultivar development from a molecular perspective, by following the inheritance of RFLP markers in a pedigree analysis. Five methods of analysis are included in this dissertation;Sixty-four plant introductions, cultivars, and breeding lines were analyzed to define a core set of 97 probes with a high likelihood of detecting a polymorphism in elite germplasm. The ability to trace regions of chromosomes from parent to offspring and the application of pedigree-based mapping was demonstrated, which is the cosegregation of phenotypic traits and RFLP markers based on pedigree information ...


Novel Suicide Elements For Gene Disruption In Escherichia Coli, Brian Christopher Nicholson Jan 1994

Novel Suicide Elements For Gene Disruption In Escherichia Coli, Brian Christopher Nicholson

Dissertations, Theses, and Masters Projects

No abstract provided.


Xenopus Laevis Ribosomal Protein S1: Evidence For Regulation At The Transcriptional Level, Cleve Ray-Dean Sinor Jan 1994

Xenopus Laevis Ribosomal Protein S1: Evidence For Regulation At The Transcriptional Level, Cleve Ray-Dean Sinor

Dissertations, Theses, and Masters Projects

No abstract provided.


Mitochondrial Dna Variation In Natural And Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck) And The Calico Scallop, Argopecten Gibbus (Dall), Sandra Grace Blake Jan 1994

Mitochondrial Dna Variation In Natural And Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck) And The Calico Scallop, Argopecten Gibbus (Dall), Sandra Grace Blake

Dissertations, Theses, and Masters Projects

No abstract provided.


Regulation Of Mitogen Regulated Protein/Proliferin Gene Expression In 3t3 Cells By Basic Fibroblast Growth Factor , Manzoor Ali P. K. Mohideen Jan 1994

Regulation Of Mitogen Regulated Protein/Proliferin Gene Expression In 3t3 Cells By Basic Fibroblast Growth Factor , Manzoor Ali P. K. Mohideen

Retrospective Theses and Dissertations

Mitogen regulated protein/proliferin (MRP/PLF) is a murine uterine growth factor belonging to the prolactin/growth hormone gene superfamily. Basic fibroblast growth factor (bFGF) regulates its expression in 3T3 cells and is speculated to be among its regulators in vivo. In order to gain insights into its regulation, experiments were performed to elucidate the mechanisms by which bFGF regulates mrp/plf gene expression in 3T3 cells. RT-PCR analyses demonstrated that of the three different forms of MRP/PLF proteins only one, PLF1, is expressed in these cells in response to bFGF. PLF1 could be the product of either plf42 ...


Molecular Characterization Of Porcine Respiratory Coronavirus Isolates With Varying Pathogenicity , Eric Martin Vaughn Jan 1994

Molecular Characterization Of Porcine Respiratory Coronavirus Isolates With Varying Pathogenicity , Eric Martin Vaughn

Retrospective Theses and Dissertations

Three new isolates of porcine respiratory coronavirus (PRCV) were isolated and characterized. Two of the PRCV isolates, AR310 and LEPP, were shown to produce moderate interstitial pneumonia, whereas the third PRCV isolate, IA1894, was only mildly pathogenic in five-week-old specific pathogen free pigs. The previously described PRCV isolate ISU-1, a mildly pathogenic PRCV isolate, was also included in this study. These PRCV isolates with varying pathogenicity provided an opportunity to determine if there are certain genes that correlate with virulence, as the genes 3 and 3-1 have been hypothesized to be virulence determinants for transmissible gastroenteritis virus (TGEV) isolates. Using ...


Expression Of Chlamydomonas Reinhardtii Periplasmic Carbonic Anhydrase In Escherichia Coli And Transgenic Tobacco Plants , Cyril Sebastian Roberts Jan 1994

Expression Of Chlamydomonas Reinhardtii Periplasmic Carbonic Anhydrase In Escherichia Coli And Transgenic Tobacco Plants , Cyril Sebastian Roberts

Retrospective Theses and Dissertations

Carbonic anhydrase (CA) catalyzes the reversible hydration of CO2. The periplasmic CA gene CAH1 of Chlamydomonas reinhardtii codes for a highly processed secreted glycoprotein. The primary translation product of the CAH1 gene is targeted to the algae's ER, where it is proteolytically processed to yield two different subunits, glycosylated, assembled into an active heterotetramer, and secreted. Expression of CAH1 in Escherichia coli and tobacco plants were effected in this study. For bacterial expression, two constructs, one with and another without, the algal target leader sequence were used. Similarly, after replacing the algal's target leader sequence with that from ...


Purification, Characterization And Cloning Of A Periplasmic Catalase From B Abortus And The Role It Plays In The Pathogenesis Of Brucella , Zheng Yu Sha Jan 1994

Purification, Characterization And Cloning Of A Periplasmic Catalase From B Abortus And The Role It Plays In The Pathogenesis Of Brucella , Zheng Yu Sha

Retrospective Theses and Dissertations

A periplasmic catalase has been identified and purified from Brucella abortus using a procedure which fractionates periplasmic B. abortus proteins from other cellular components while retaining biological activity. The biochemical characteristics of the purified enzyme were studied and the gene encoding the enzyme cloned and sequenced. SDS polyacrylamide gel electrophoresis of the purified enzyme revealed only a single subunit with a molecular weight of 59,000. Gel filtration indicates the native protein is a tetramer. The native protein has a visible absorption spectrum with maxima at 407, 501, and 628 nm which is typical of mammalian, but not some bacterial ...


Characterization And Immunogenicity Of The Heat Shock Protein, Hsp60 Of Brucella Abortus , Dennis Gor Jan 1994

Characterization And Immunogenicity Of The Heat Shock Protein, Hsp60 Of Brucella Abortus , Dennis Gor

Retrospective Theses and Dissertations

Brucella abortus is the causative agent of bovine brucellosis, a disease that causes spontaneous abortion in cows. The most effective form of protection against this pathogen is immunization; however, Brucella abortus strain 19 (the standard vaccine against Brucella abortus) is not completely protective. The vaccination of laboratory mice with the heat shock protein, hsp60 derived from Brucella abortus, using live attenuated recombinant Salmonella typhimurium expressing this protein (hsp60) as a delivery system, and the characterization of the immune response to Brucella abortus hsp60 over a 12 week time course following vaccination is described;Infection of BALB/c strain of laboratory ...


An Analysis Of Mitochondrial Dna In Rett Syndrome And Other Neurodegenerative Disorders, Catherine Erickson Burgess Jan 1994

An Analysis Of Mitochondrial Dna In Rett Syndrome And Other Neurodegenerative Disorders, Catherine Erickson Burgess

Theses and Dissertations in Biomedical Sciences

Mitochondrial dysfunction resulting from mutations on mitochondrial DNA (mtDNA) is being recognized in a growing spectrum of diseases. These diseases, resulting from single base mutations, large deletions, or insertions, have been largely neuromuscular in origin. However, as an understanding of the effects of mtDNA mutations progresses, attention is now focusing on neurodegenerative diseases. Rett Syndrome (RS), a progressive neurodegenerative disease with predominantly female cases, demonstrates morphologic mitochondrial changes, mitochondrial enzyme deficiencies and maternal inheritance (characteristic of mtDNA diseases). No investigation of mtDNA involvement has been previously conducted and, to date, no biological marker exists for this disorder.

Our preliminary studies ...


Structure And Function Of Unmodified E. Coli Valine-Trna , Dongxian Yue Jan 1994

Structure And Function Of Unmodified E. Coli Valine-Trna , Dongxian Yue

Retrospective Theses and Dissertations

The effects of nucleoside modifications on E. coli tRNA[superscript]Val structure have been probed by imino [superscript]1H NMR. The NMR data shows that the structure of in vitro transcribed (unmodified) and native (modified) tRNA[superscript] Val are very similar in 15 mM Mg[superscript]2+. Temperature dependence of the spectra reveals that nucleoside modifications stabilize tertiary interactions between T and D loops. On removal of Mg[superscript]2+, unmodified tRNA[superscript] Val undergoes remarkable structural changes which are not observed in native tRNA[superscript] Val. There is near total disruption of the D stem and of tertiary interactions ...


G-Wires: The Growth And Characterization Of A G4-Dna Nanostructure , Thomas Cosgrove Marsh Jan 1994

G-Wires: The Growth And Characterization Of A G4-Dna Nanostructure , Thomas Cosgrove Marsh

Retrospective Theses and Dissertations

Guanine-rich sequences are vital components in the genomes of many organisms. For example, G-rich sequences are found in telomeres, fragile X locus, promoters, IgG switch regions, recombinational hot spots and the HIV RNA dimerization domain. The functions of these G-rich sequences rely in part on guanine self-recognition. G-rich sequences can adopt a quadruple helical conformation in the presence of specific monovalent and divalent metal cations which are also required for maintaining the quadruplex stability. The structural basis of the quadruplex is a cyclic Hoogsteen hydrogen bonded guanine tetrad known as the G-quartet. Sequences capable of forming G-quartets are classified as ...


Molecular And Ultrastructural Aspects Of The Adaptation Of Chlamydomonas Reinhardtii To Limiting Co2 , Anne Margaret Geraghty Jan 1994

Molecular And Ultrastructural Aspects Of The Adaptation Of Chlamydomonas Reinhardtii To Limiting Co2 , Anne Margaret Geraghty

Retrospective Theses and Dissertations

Change occurring in Chlamydomonas reinhardtii as cells adapt to limiting CO2 conditions were examined at both a molecular level and an ultrastructural level. It was demonstrated using antibodies that the time course of the de novo synthesis of LIP-21, a 21 kD limiting-CO2 induced polypeptide, correlates with the appearance of CO2 concentrating activity and that expression of the nuclear gene for LIP-21 is regulated at the level of translatable message. These results are consistent with LIP-21 being a component of an adaptive response to limiting CO2, such as the induction of the CO2 concentrating mechanism. Phase separation of membrane proteins ...


Identification Of Potential Oat Phytochrome A Mrna Degradation Mechanisms , David Charles Higgs Jan 1994

Identification Of Potential Oat Phytochrome A Mrna Degradation Mechanisms , David Charles Higgs

Retrospective Theses and Dissertations

The phytochrome plant photoreceptor is important for perceiving the light environment and initiating plant developmental and environmental responses. When dark-grown oat seedlings are treated with light the phytochrome A (PHYA) mRNA abundance rapidly declines due, in part, to the inherent instability of the PHYA mRNA. Messenger RNA stability is an important process in regulating eukaryotic gene expression. My primary goal was to investigate both the mechanism of oat PHYA mRNA degradation and cis-acting sequences involved in regulating oat PHYA mRNA degradation. An oat protoplast system was established to investigate its use as a quick and reliable system to study plant ...


Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, Qijing Zhang Jan 1994

Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, Qijing Zhang

Retrospective Theses and Dissertations

A microtiter plate adherence assay for Mycoplasma hyopneumoniae was established by using purified swine tracheal cilia which are the natural targets for the mycoplasma. M. hyopneumoniae bound specifically to solubilized cilia immobilized onto microtiter plates. Dextran sulfate, heparin, chondroitin sulfate, laminin, mucin, and fucoidan significantly inhibited binding of the mycoplasmas to cilia. Heparin, mucin, fucoidan, and chondroitin sulfate interacted with the adhesins on the surface of mycoplasmas, whereas laminin blocked the receptors in cilia. Treatment of cilia with neuraminidase appeared to promote adherence of the mycoplasmas; whereas, treatment of cilia with sodium metaperiodate decreased the binding. In the second study ...


Telomeric Nucleic Acids: C-Strand Structure And A Telomerase Rna Mutant , Shawn Cameron Ahmed Jan 1994

Telomeric Nucleic Acids: C-Strand Structure And A Telomerase Rna Mutant , Shawn Cameron Ahmed

Retrospective Theses and Dissertations

Telomeres, the ends of linear chromosomes, are composed of simple tandem repeats which are usually G·C rich. Telomeres are essential for chromosome stability, organizing the nuclear architecture and ensuring complete replication of the chromosomal terminus. To understand how telomeres carry out these fundamental cellular roles, one must understand the structural and dynamic properties of telomeric repeat sequences. Structural and genetic approaches were taken to learn more about telomeric nucleic acids;The structural portion of my research concerned an unusual DNA structure formed by the C-rich strand of telomeric DNA. Telomeric C-strand sequences form non-Watson-Crick structures in supercoiled plasmids at ...


Genetic Analysis Of Pseudohyphal Growth In The Budding Yeast Saccharomyces Cerevisiae , Melissa Jo Blacketer Jan 1994

Genetic Analysis Of Pseudohyphal Growth In The Budding Yeast Saccharomyces Cerevisiae , Melissa Jo Blacketer

Retrospective Theses and Dissertations

The budding yeast Saccharomyces cerevisiae is a dimorphic organism that can assume either a yeast-like or pseudohyphal form. Nitrogen limitation induces pseudohyphal growth, which is characterized by branched chains of elongated cells. Pseudohyphal cells can grow invasively in agar medium, whereas yeast-like cells do not. To identify factors involved in morphologic differentiation, S. cerevisiae mutants exhibiting a constitutive cell elongation morphology were isolated. Genetic analysis identified 28 recessive and 2 semi-dominant mutations that cause abnormal morphology, and placed these in 14 distinct gene loci, termed ELM, for ELongated Morphology. Many elm mutations cause multiple aspects of pseudohyphal growth, and thus ...


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 ...


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.


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 ...


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 ...


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 ...


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 ...