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Articles 1 - 27 of 27

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

Cell Envelope Constituents Of Pseudomonas Putida Contributing To Growth And Survival In Low-Water-Content Habitats , Martinus Franciscus Maria Van De Mortel Jan 2005

Cell Envelope Constituents Of Pseudomonas Putida Contributing To Growth And Survival In Low-Water-Content Habitats , Martinus Franciscus Maria Van De Mortel

Retrospective Theses and Dissertations

The ability of bacteria to respond to the ever changing environmental conditions they encounter requires the utilization of a broad range of colonization and survival strategies. One of the most important and probably least understood factors determining bacterial activity in terrestrial habitats is water availability. The goal of this dissertation research was to identify traits that contribute to maintaining a functional cell envelope when cells are dehydrated, which will help us to assess the scope of physiological changes necessary for growth in low-water-content habitats. The primary objective was to identify genes that are specifically regulated by dehydration (matric stress), and ...


Characterization Of The Ftsyex Operon Of Escherichia Coli , Becky Graham Jan 2002

Characterization Of The Ftsyex Operon Of Escherichia Coli , Becky Graham

Retrospective Theses and Dissertations

The ftsYEX operon of Escherichia coli historically has been described as a cluster of essential cell division genes. Filamentation temperature-sensitive (fts) designates a class of mutants that displays normal cell morphology at the permissive temperature of 30°C, but filaments and dies at the restrictive temperature of 42°C. The first gene, ftsY, is known to encode an essential component of a protein localization system first described in eukaryotes, the signal recognition particle (SRP) pathway. The function of the following genes, ftsE and ftsX, are much less understood. It has been shown that FtsE and FtsX comprise a two-component ATP-binding ...


Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan Jan 1999

Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan

Retrospective Theses and Dissertations

Members of the lentivirus subfamily of retroviruses are characterized as causing slow, chronic disease. Atypical of other lentiviruses, such as human immunodeficiency virus type 1, equine infectious anemia virus (EIAV) may produce a rapid, variable disease course in horses. Infected horses may undergo an, acute episode of disease involving viremia, fever, and thrombocytopenia. Following this acute period, horses may resolve to an inapparent infection or suffer a chronic period of additional cycles of viremia, fever, and thrombocytopenia. Horses which survive clinical episodes usually become inapparent carriers of the virus for life. Numerous virus and host factors contribute to the phenotypic ...


Analysis Of Viral Proteins Of Porcine Reproductive And Respiratory Syndrome Virus In Host Protection And Early Virus-Cell Interactions , Yanjin Zhang Jan 1998

Analysis Of Viral Proteins Of Porcine Reproductive And Respiratory Syndrome Virus In Host Protection And Early Virus-Cell Interactions , Yanjin Zhang

Retrospective Theses and Dissertations

The viral proteins of porcine reproductive and respiratory syndrome virus (PRRSV) were expressed in a baculovirus expression system. They were evaluated for protection of pigs against the respiratory disease and for function in virus-cell interactions. The open reading frames 2 to 6 products were confirmed to be membrane associated proteins as they were detected on the surface of viable insect cells by an immunofluorescence assay. Immunization of pigs with vaccines comprised of a combination of GP2, GP3 and GP4 or a combination of GP5, M and N proteins induced partial protection, but immunization with combination of GP5 and M proteins ...


Pou Domain Genes And The Immunoglobulin Octamer Motif In Chickens , Lynn Marie Heltemes Jan 1997

Pou Domain Genes And The Immunoglobulin Octamer Motif In Chickens , Lynn Marie Heltemes

Retrospective Theses and Dissertations

This research was undertaken to test the hypothesis that multiple POU genes exist and that POU proteins are involved in transcriptional regulation in the chicken. The POU protein Oct-2 has been hypothesized to partially regulate immunoglobulin gene expression through its interaction with the octamer motif found in the promoter of immunoglobulin genes. Transcriptional regulation of immunoglobulin genes provides a model for tissue-specific gene expression in the immune system. In searching for a chicken Oct-2 homologue, two partial chicken POU domain genes were identified. A cDNA clone encoding the POU domain of Brn-3a was isolated and showed near identity to the ...


Identification Of Genes In Tn916 Encoding Membrane-Targeted Proteins, Suganda Loe Jan 1997

Identification Of Genes In Tn916 Encoding Membrane-Targeted Proteins, Suganda Loe

Retrospective Theses and Dissertations

Tn916 is a 18 kb, broad-host range conjugative transposon originally isolated from Enterococcus faecalis. Transposon TnphoA was used to identify genes in Tn916 encoding for membrane-targeted proteins or for secretion. Sixty five independent PhoA+ gene fusions were isolated. These insertions clustered into two regions, open reading frames 13 and 15 (Flanagan et al., Plasmid 32:350-354). These TnphoA insertional mutations in resulted in a Tn+ (ability to transpose intracellularly) and Tra- (inability to transfer conjugatively) phenotype. The hydrophathy analysis of ORF13 and ORF15 revealed that these proteins lack the classical signal peptides necessary for protein export, suggesting that these two ...


Sequence And Functional Analysis Of The P97 Swine Cilium Adhesin Gene Of Mycoplasma Hyopneumoniae , Tsungda Hsu Jan 1997

Sequence And Functional Analysis Of The P97 Swine Cilium Adhesin Gene Of Mycoplasma Hyopneumoniae , Tsungda Hsu

Retrospective Theses and Dissertations

Mycoplasma hyopneumoniae causes swine enzootic pneumonia, an important disease in the swine industry. Adherence of M. hyopneumoniae to the cilia of the tracheal epithelial cells is required to establish infection. Previous studies have identified a 97-kDa protein (P97) as the putative ciliary adhesin. To further characterize the P97 protein, the gene has been cloned, its DNA sequence analyzed, and the function of the P97 protein expressed in Escherichia coli studied. These results demonstrated that recombinant P97 has swine ciliary adherence activity. Further analysis revealed that the P97 gene was translated as a 124.9-kilodalton (kDa) protein and subjected to proteolytic ...


Bacterial Physiology And Enzymology Of The Membrane-Associated Methane Monooxygenase And Ammonia Oxidation System From Methylococcus Capsulatus Bath, 1992-1996 , James Allan Zahn Jan 1996

Bacterial Physiology And Enzymology Of The Membrane-Associated Methane Monooxygenase And Ammonia Oxidation System From Methylococcus Capsulatus Bath, 1992-1996 , James Allan Zahn

Retrospective Theses and Dissertations

The enzymology and microbial physiology of methane and ammonia oxidation by the membrane-associated methane monooxygenase (pMMO) from the obligate methylotroph, Methylococcus capsulatus Bath were studied. Conditions leading to the stabilization of the pMMO were defined, and an active preparation of the pMMO from M. capsulatus Bath was isolated by ion exchange and hydrophobic interaction chromatography using dodecyl-[beta]-D-maltoside as the detergent. The active preparation consisted of three major polypeptides with molecular masses of 47,000 and 27,000, and 25,000 Da and contained 2.5 iron and 14.5 copper atoms per mole of enzyme. The 27,000 ...


Cloning Of Bovine Intercellular Adhesion Molecules And Characterization Of Expression Of Neutrophil Adhesion Molecules In Periparturient Cows And Calves , Eunkyung Lee Jan 1996

Cloning Of Bovine Intercellular Adhesion Molecules And Characterization Of Expression Of Neutrophil Adhesion Molecules In Periparturient Cows And Calves , Eunkyung Lee

Retrospective Theses and Dissertations

The interactions of circulating leukocytes with the endothelium represent a key point in the effector functions of the immune system by regulating the specificity and strength of cell-cell interactions. The recruitment of neutrophils to sites of inflammation is initiated by chemoattractants. The initial contact of neutrophils on vascular endothelial cells is a rolling interaction mediated by members of the selectin family. These include E-selectin and P-selectin on the surface of activated endothelial cells, and L-selectin on neutrophils. The subsequent activation of leukocyte [beta]2 integrins, which bind to the glycoprotein intercellular adhesion molecule-1 (ICAM-1) on endothelial cells, is essential for ...


Characterization Of Membrane-Associated Nuclease Activity In Mycoplasma Pulmonis , Karalee Jean Jarvill-Taylor Jan 1996

Characterization Of Membrane-Associated Nuclease Activity In Mycoplasma Pulmonis , Karalee Jean Jarvill-Taylor

Retrospective Theses and Dissertations

Mycoplasmas are deficient in numerous biosynthetic pathways. Consequently, growth is dependent upon the acquisition of structural and macromolecular precursors from the environment. These precursors include phospholipids, fatty acids and nucleotide bases. DNases and RNases are postulated to be involved in the acquisition of nucleotides. The goals of this study were to determine if nuclease activities are universally associated with mycoplasmas, characterize the nucleases by subcellular distribution and apparent molecular weight, and to identify and analyze the nuclease gene(s) in Mycoplasma pulmonis;Nuclease activity was present in all mycoplasma species tested. The level of activity did not correlate with virulence ...


Genetic And Biochemical Characterization Of Brucella Abortus Strain Rb51 , Allen Elroy Jensen Jan 1995

Genetic And Biochemical Characterization Of Brucella Abortus Strain Rb51 , Allen Elroy Jensen

Retrospective Theses and Dissertations

Brucella abortus strain RB51, a naturally derived rough variant, has been proposed to replace strain 19 for use as a vaccine against brucellosis in cattle. Utilizing fingerprinting and standard biotyping techniques, it was possible to differentiate RB51 from other brucellae and to ascertain the stability of RB51. Standardization of a genomic fingerprinting procedure using restriction endonuclease profiles of total DNA from Brucella are described. Although the focus was principally on B. abortus isolates from cattle, the investigation included field isolates from bison and elk, reference strains, vaccinal strains, and genetically-engineered brucellae;Pulsed-field gel electrophoresis profiles of the reference type strains ...


Expression And Characterization Of Bovine Rotavirus Proteins In The Baculovirus System , Young Soo Lyoo Jan 1995

Expression And Characterization Of Bovine Rotavirus Proteins In The Baculovirus System , Young Soo Lyoo

Retrospective Theses and Dissertations

Recombinant proteins of bovine rotavirus VP2, VP4, VP6 and VP7 were expressed in insect cells using baculovirus expression vectors. Expressed recombinant proteins were similar to those of rotavirus. Recombinant viral antigens expressed in insect cells reacted with polyclonal antiserum to the VMRI strain of BRV by an indirect immunofluorescence test. Expressed recombinant proteins were characterized by radioimmunoprecipitation and their molecular mass was found to be similar to that of in wild type rotavirus. These four recombinant proteins were antigenic in guinea pigs and induced antibodies to the corresponding rotavirus proteins as detected by indirect immunofluorescence test. Recombinant viruses Bac.pVL ...


Compilation And Analysis Of Mycobacterium Paratuberculosis Promoters , John Patrick Bannantine Jan 1995

Compilation And Analysis Of Mycobacterium Paratuberculosis Promoters , John Patrick Bannantine

Retrospective Theses and Dissertations

Mycobacterium paratuberculosis transcriptional and translational signals were studied to gain insight into gene expression in this organism. To study M. paratuberculosis promoter structures, a more versatile promoter selection vector was constructed from the pKO1 parent vector. This new plasmid, pJJ2, was used to identify 11 promoter fragments from an M. paratuberculosis DNA library. In addition, a previously characterized M. paratuberculosis promoter, contained in a 493-bp EcoRI fragment, was cloned into the new vector to test the efficacy in cloning novel M. paratuberculosis promoters. In a related study, an expression probe shuttle plasmid (pYUB76) was employed to clone M. paratuberculosis expression ...


Biosynthetic Pathways In Oxalobacter Formigenes , Nancy A. Cornick Jan 1995

Biosynthetic Pathways In Oxalobacter Formigenes , Nancy A. Cornick

Retrospective Theses and Dissertations

Oxalate is the only substrate that supports the growth of the gram negative anaerobe, Oxalobacter formigenes. Oxalate is decarboxylated to formate plus CO[subscript]2. A small amount of acetate (0.5-1 mM) is required for biosynthetic reactions. Oxalate is reduced and assimilated into cell biomass by aerobic oxalate-degrading bacteria using either the glycerate pathway or the serine pathway. Oxalate is reduced to 3P-glycerate and assimilated as a C[subscript]3 unit. We detected the enzymatic activities of glycerate pathway but not those of the serine pathway in cell-free extracts of O. formigenes;Four potential sources of carbon for cell ...


Identification And Characterization Of A Chicken Major Histocompatibility Complex Class Ii[Beta] Gene Promoter , Yunfei Chen Jan 1995

Identification And Characterization Of A Chicken Major Histocompatibility Complex Class Ii[Beta] Gene Promoter , Yunfei Chen

Retrospective Theses and Dissertations

The major histocompatibility complex (MHC) contains a variety of genes. Among them, the class II genes encode proteins involved in antigen presentation to helper T cells, a key step in initiating immune responses. The regulation of class II gene expression has been extensively studied in mammals. Such studies have been lacking in the avian species, despite the well-established association of the avian MHC with disease resistance and production traits. The objective of this study was to functionally analyze a putative chicken MHC class II gene promoter;Using the chloramphenicol acetyltransferase (CAT) reporter system, a functional chicken MHC class II[beta ...


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 ...


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 ...


Identification And Characterization Of Mycoplasma Promoters , Kevin Lee Knudtson Jan 1993

Identification And Characterization Of Mycoplasma Promoters , Kevin Lee Knudtson

Retrospective Theses and Dissertations

The development of a reporter gene system for mycoplasmas was sought to be able to examine gene regulation in mycoplasmas. Initial studies were designed to examine whether the Escherichia coli lacZ gene could be used as a reporter gene in mycoplasmas. The test system examined the ability of the Mycoplasma capricolum rrnA P2 or E. coli rrnB P1 promoters to initiate the transcription of trp[superscript]'-lacZYA in Acholeplasma ISM1499. The results showed that the M. capricolum, but not the E. coli promoter, could promote the expression of lacZ. Because the test system was based on a translational fusion that ...


Characterization Of The 31-Kda Antigen Gene Of Haemophilus Somnus And Its Product , Jonghwa Won Jan 1993

Characterization Of The 31-Kda Antigen Gene Of Haemophilus Somnus And Its Product , Jonghwa Won

Retrospective Theses and Dissertations

Consistent immunoreactivities of the 31-, 40- and 78-kDa proteins of Haemophilus somnus were observed in immunoblots with bovine antisera to H. somnus. A genomic library of H. somnus 8025 DNA was constructed in plasmid pUC19 and 45 recombinants expressed immunoreactive proteins in Western blots using bovine antiserum. Ten of the recombinants expressing a 31-kDa protein caused lysis of bovine erythrocytes. Restriction endonuclease mapping indicated that the hemolytic recombinants shared an approximately 1.7-kb BglII fragment. Southern blot analysis using the BglII fragment as a probe revealed homology among the recombinants and the presence of an identically sized BglII fragment in ...


Characterization Of The Periplasmic Flagella Proteins Of Leptospira Spp And Cloning Of A Related Gene , Gabriel Antonio Trueba Jan 1993

Characterization Of The Periplasmic Flagella Proteins Of Leptospira Spp And Cloning Of A Related Gene , Gabriel Antonio Trueba

Retrospective Theses and Dissertations

The structure and composition of periplasmic flagella (PF) of Leptospira interrogans were analyzed. Electron microscopic observations showed that leptospiral PFs are complex structures composed of an 11.3 nm diameter core and two sheaths. Image analysis revealed sheathed PFs with two different diameters; one of 21.5 nm diameter and the other 42 nm diameter. Two dimensional protein electrophoresis of purified PFs demonstrated the presence of at least seven proteins. The molecular masses of the PF proteins ranged from 31.5 kDa to 36 kDa. Monoclonal antibodies against PF proteins and polyclonal antibodies against gel-purified PF proteins were developed. Immunoelectron ...


Genetic And Physical Analysis Of The Staphylococcus Aureus Chromosome Using Two Tn917 Derivatives , Laura Lea Hruska Jan 1993

Genetic And Physical Analysis Of The Staphylococcus Aureus Chromosome Using Two Tn917 Derivatives , Laura Lea Hruska

Retrospective Theses and Dissertations

Tandem chromosomal duplications offer a means of genetic and physical mapping in microorganisms which lack defined conjugal systems. To determine if tandem chromosomal duplications occur in S. aureus, two libraries of transposon-induced auxotrophic mutations with different resistance phenotypes were needed;To complement the existing library of Tn551-induced auxotrophs, two Tn917lac derivatives were constructed: Tn917G, which contains the gentamicin-resistance gene of Tn4001, and Tn917T, which contains the tetracycline-resistance gene of pT181 and sequences of the Gram-negative cloning vector p34H. Transposon mutagenesis performed with Tn917G and Tn917T demonstrated that these two constructs are useful tools in the genetic analysis of the S ...


Molecular Mechanisms Controlling Bovine Lymphocyte Homing , Brad Thomas Bosworth Jan 1991

Molecular Mechanisms Controlling Bovine Lymphocyte Homing , Brad Thomas Bosworth

Retrospective Theses and Dissertations

The cDNA clones encoding for the bovine glycoproteins CD44 and LECAM-1 (lectin cell adhesion molecule-1) were isolated and sequenced. The predicted amino acid sequences of bovine CD44 and LECAM-1 had high identities with those of human and murine CD44 and LECAM-1. The high identities of the predicted amino acid sequences of these glycoproteins in the bovine, human and mouse suggest they may have similar functions in all three species. While the overall amino acid identities were high, bovine CD44 had an area of low identity with human and murine CD44 in the extracellular domain and the cytoplasmic tail of bovine ...


Isolation Of Upstream Control Regions Of Genes Expressed At Different Times During Growth And Sporulation In Bacillus Thuringiensis , John Michael Hurley Jan 1989

Isolation Of Upstream Control Regions Of Genes Expressed At Different Times During Growth And Sporulation In Bacillus Thuringiensis , John Michael Hurley

Retrospective Theses and Dissertations

To investigate the mechanisms of gene expression in Bacillus thuringiensis subsp. kurstaki HD251, HindIII-digested total DNA was ligated into plasmid pKO1, which contains a promoterless galK gene. E. coli HB101 (GalK[superscript]-) transformant colonies resistant to ampicillin and red in color on MacConkey-galactose agar (indicating transformation to the GalK[superscript]+ phenotype) presumably contain B. thuringiensis DNA inserts in pKO1 that function as promoters in E. coli. To determine if such sequences control gene expression in B. thuringiensis, total RNA probes were prepared from cultures at specified times throughout growth and sporulation and used to screen plasmid DNA "dot-blots." Several plasmids ...


The Construction And Properties Of An Integrable Plasmid For Genomic Analysis In Staphylococcus Aureus , John Bernard Luchansky Jan 1987

The Construction And Properties Of An Integrable Plasmid For Genomic Analysis In Staphylococcus Aureus , John Bernard Luchansky

Retrospective Theses and Dissertations

An improved system for transforming protoplasts of Staphylococcus aureus with plasmid DNA was developed to facilitate the construction of an integrable plasmid. Protoplast transformants were recovered at higher frequencies when the protoplasts were warmed to 56 C immediately prior to the addition of cesium chloride-purified plasmid DNAs. More transformants were recovered when the protoplast-DNA mixture was plated on R agar than on DM3 medium, and when the selective agent was incorporated directly in the medium rather than supplied in an agar overlay. More transformants were recovered when the protoplast-DNA mixture was incubated at 30 C for 3.5 h before ...


Production And Use Of Monoclonal Antibodies For Molecular Characterization, Affinity Purification, And Serological Detection Of Economically Significant Plant Viruses , Robert Diaco Jan 1985

Production And Use Of Monoclonal Antibodies For Molecular Characterization, Affinity Purification, And Serological Detection Of Economically Significant Plant Viruses , Robert Diaco

Retrospective Theses and Dissertations

Hybridomas secreting monoclonal antibodies (M-Abs) against three isolates of barley yellow dwarf virus (BYDV) were established. Two M-Abs were generated against the MAV isolate, one against RPV, and six against P-PAV. None of the M-Abs reacted with healthy host components. Reactions of M-Abs, or unlabelled polyclonal antisera, in an indirect enzyme-linked immunosorbent assay (ELISA) indicate the presence of a common epitope on all three virus isolates. BYDV dissociated when incubated in carbonate-bicarbonate coating buffer at pH 9.6; stabilization was achieved by predialysis with either 2% formaldehyde or 2% glutaraldehyde. In indirect ELISA, unlabelled polyclonal antisera bound to both stabilized ...


The Bacterial Degradation Of Leucine , Roland Walter Kinney Jan 1960

The Bacterial Degradation Of Leucine , Roland Walter Kinney

Retrospective Theses and Dissertations

No abstract provided.


Temperature And The Growth Of Yeast , Frank F. Sherwood Jan 1924

Temperature And The Growth Of Yeast , Frank F. Sherwood

Retrospective Theses and Dissertations

No abstract provided.