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Articles 8041 - 8070 of 8422

Full-Text Articles in Microbiology

Restriction Mapping And Expression Of Recombinant Plasmids Containing The Arsenic Resistance Genes Of The Plasmid R45, Terry M. Coons Jan 1986

Restriction Mapping And Expression Of Recombinant Plasmids Containing The Arsenic Resistance Genes Of The Plasmid R45, Terry M. Coons

Dissertations and Theses

The trivalent (arsenite) and pentavalent (arsenate) forms of arsenic are introduced into the environment through the use of arsenic in herbicides, pesticides, fertilizers, and the smelting of arsenic-bearing ores. Bacteria resistant to arsenic are readily isolated from surface waters, sewage, and clinical infections. Although some bacterial resistance is provided by inducible phosphate transport systems that discriminate against arsenate, marked resistance is carried on bacterial plasmids.

A 6.9 kilobase fragment previously derived from one such plasmid, R45, and containing the genes for inducible resistance to arsenite and arsenate was ligated into the cloning vectors puce and pUC9 in opposite orientations and …


Stability Of The Larvicidal Activity Of Bacillus Thuringiensis Subsp. Israelensis: Amino Acid Modification And Denaturants, Mary Ann Pfannenstiel, Graham A. Couche, Ganapathy Muthukumar, Kenneth Nickerson Nov 1985

Stability Of The Larvicidal Activity Of Bacillus Thuringiensis Subsp. Israelensis: Amino Acid Modification And Denaturants, Mary Ann Pfannenstiel, Graham A. Couche, Ganapathy Muthukumar, Kenneth Nickerson

Papers in Microbiology

The Bacillus thuringiensis subsp. israelensis mosquito larvicidal toxin is not a sulfhydryl-activated toxin. The protein disulfide bonds were cleaved and blocked without loss of toxicity. In contrast, modification of the lysine side chains eliminated toxicity. Additionally, the toxin was resistant to high concentrations of salt (8 M NaBr), organic solvents (40% methanol), denaturants (4 M urea), and neutral detergents (10% Triton X-100). However, it was inactivated by both positively and negatively charged detergents and by guanidine hydrochloride.


Footrot In Sheep And Goats, Department Of Agriculture, Western Australia Oct 1985

Footrot In Sheep And Goats, Department Of Agriculture, Western Australia

Animal production and livestock published reports

Reference to sheep in this pamphlet applies equally to goats.

Footrot is a contagious disease of sheep and goats caused by the bacterium Baueroides nodosus.

The bacterium can cause varying degrees of damage to the horn of the foot. The resulting infection can lead to lameness and serious loss of body condition.


Isolation And Characterization Of A Novel Motility Mutant In Salmonella Typhimurium, David Matthew Chacko Sep 1985

Isolation And Characterization Of A Novel Motility Mutant In Salmonella Typhimurium, David Matthew Chacko

Loma Linda University Electronic Theses, Dissertations & Projects

A new mutant, BT40, isolated from mutagenized cultures of S. typhimurium was deficient in chemotaxis (Che- phenotype) in tryptone semisoft agar, but had random motility with a tumbling frequency (37%) similar to that of the parental strain, ST23 (39%). In spatial assays accumulation of BT40 cells in capillary tubes containing attractants was decreased by 33%-59% compared to ST23, but BT40 had a normal response to attractants in temporal assays. The methylation level of the chemotactic proteins was decreased in BT40. At room temperature, the mean swimming speed was 11 μm/s for BT40 and 20 μm/s for ST23; more BT40 …


A Rapid Concentration And Identification Technique For Human Malaria Infections Using A Mouse Model, Donald D. Barton Sep 1985

A Rapid Concentration And Identification Technique For Human Malaria Infections Using A Mouse Model, Donald D. Barton

Loma Linda University Electronic Theses, Dissertations & Projects

Red blood cells infected with malaria parasites experience a change in density making them lighter (less dense). This paper reports a new, rapid diagnostic technique using this change in density in the infected red blood cell. It is not only easy to use, but it is also compatible with the technological conditions found where the malaria problem is most acute - in many developing countries of the world. A small sample of blood drawn from a simple finger stick can be concentrated and examined microscopically for malaria parasites within 10 minutes. The thick film slide preparation, presently used, takes a …


Assay For Rifampicin Resistant M13 Rf Synthesis, Carol Bauer Wheeler Sep 1985

Assay For Rifampicin Resistant M13 Rf Synthesis, Carol Bauer Wheeler

Loma Linda University Electronic Theses, Dissertations & Projects

We have developed a rapid assay which can detect the function of the origin of 0X174 complementary strand DNA in Ml3 by virtue of its ability to initiate the synthesis of M13 complementary strands in the presence of the antibiotic rifampicin. A segment of DNA carrying the sequence recognized by the replication protein n' has been isolated from bacteriophage ØX174 and cloned into an Ml3 bacteriophage vector. Protein n' is a component of the bacterial primosome, a multi-protein assembly which initiates the synthesis of primers during DNA replication in the bacterium Escherichia coli. The recognition site for n' on the …


A Preliminary Investigation Of The Effect Of Storm Events On The Concentration Of Volatile Organic Compounds In The Lost River Cave System, Warren County, Kentucky, Francis Michael Cretella Aug 1985

A Preliminary Investigation Of The Effect Of Storm Events On The Concentration Of Volatile Organic Compounds In The Lost River Cave System, Warren County, Kentucky, Francis Michael Cretella

Masters Theses & Specialist Projects

Samples of cave water were analyzed for volatile organic compounds during four separate storm events. The major compounds detected were toluene, 1,1,1-trichloroethane, trans-1,2-dichloroethylene, methylene chloride, and 1,1-dicloroethane. Minor compounds detected were trichloroethylene, tetrachloroethylene, 1,1-dichloroethylene, and ethylbenzene. These compounds were detected in varying amounts at each of the three study sites. During a storm event, the levels of each contaminant changed significantly at all three sites studied. Two effects were observed when a storm event occurred. The first effect was the dilution of the volatile organic compounds during the storm event. These effects were related to the amount of rainfall and …


Characterization Of A New Freshwater Methanogen, Methanogenium Wolfei Sp. Nov., Theodore B. Moore Jul 1985

Characterization Of A New Freshwater Methanogen, Methanogenium Wolfei Sp. Nov., Theodore B. Moore

Dissertations and Theses

A recently isolated freshwater methanogenium species, Methanogenium wolfei, is characterized. Cells were irregular cocci, measuring 1.5 to 2.0 micrometers in diameter. No motility was observed, but 1 to 2 flagella per cell were observed after staining with Gray's Flagella Stain. Colonies formed by this species were small, shiny, and green-brown in color. Formate or hydrogen plus carbon dioxide served as substrates for growth. The optimal temperature for growth was found to be 45 degrees centigrade with minimal growth below 30 degrees centigrade and above 55 degrees centigrade. The optimal pH for growth was determined to be 6.8. Optimal growth was …


Cryptosporidiosis In The Immunosuppressed Mouse And In Cell Culture, Mercy Prabhu Das Jun 1985

Cryptosporidiosis In The Immunosuppressed Mouse And In Cell Culture, Mercy Prabhu Das

Loma Linda University Electronic Theses, Dissertations & Projects

Cryptosporidiosis is a parasitic infection primarily of animals that has been recently recognized as an important disease in immunocompromised humans. Most cases to date have occurred in patients with acquired immunodeficiency syndrome (AIDS). Persons with abnormal humoral or cellular immune function, and even normal subjects, have also been affected.

To determine whether or not mice, when experimentally immunosuppressed, would develop cryptosporidiosis, a test was designed using the AKR/J strain. This strain was selected because, it was previously reported that it was the strain shown to respond most readily to the production of disease caused by the opportunistic protozoan, Pneumocystis carinii …


A Study Of Transferable Antibiotic Resistance In Enteric Bacteria, Charles H. Regeski Jun 1985

A Study Of Transferable Antibiotic Resistance In Enteric Bacteria, Charles H. Regeski

Loma Linda University Electronic Theses, Dissertations & Projects

A group of 48 enteric bacteria was selected from a total of 170 at Loma Linda University Medical Center because of resistance to three or more antibiotics. They were examined to see if any of the antibiotic resistances were transferred by conjugation to either of two recipient bacteria. These were a restrictionless, antibiotic sensitive, azide resistant mutant of Escherichia coli K 12 designated E. coli 1228 and a similar phenotypic strain of Salmonella typhimurium LT2 designated LB 5000. Forty-three transferred one or more antibiotic resistances to either or both recipients, a frequency of 25.3% of the total bacteria and 89.6% …


Cellular Immunity In Children With Down Syndrome (Trisomy-21), Roger Lee Noble May 1985

Cellular Immunity In Children With Down Syndrome (Trisomy-21), Roger Lee Noble

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Individuals with Down syndrome (US) suffer from increased incidence of respiratory infections and lymphoblastic leukemia, and a death rate that is particularly high in the first 5 years of life. Relatively few studies have probed immune parameters in young US children. Primary immune defects in DS may be masked by a degree of immune maturity in adults, and hygienic factors may have an effect on immune capability throughout the years. A study of young children can give clearer evidence of the actual primary immune defects in DS.

Blood samples were drawn from 20 DS children under 6 years old and …


Calmodulin Levels In The Yeast And Mycelial Phases Of Ceratocystis Ulmi, Ganapathy Muthukumar, Rajiv K. Kulkarni, Kenneth W. Nickerson Apr 1985

Calmodulin Levels In The Yeast And Mycelial Phases Of Ceratocystis Ulmi, Ganapathy Muthukumar, Rajiv K. Kulkarni, Kenneth W. Nickerson

Papers in Microbiology

The calmodulin content of the yeast and mycelial phases of Ceratocystis ulmi was determined by radioimmunoassay. Calmodulin levels increased at the G1-S boundary of the cell cycle, coinciding with the first visible appearance of buds or germ tubes. However, in both phases the cellular calmodulin levels were equivalent. No differential synthesis was observed.


Lectins, El-Nasir Lalani, M Wells Mar 1985

Lectins, El-Nasir Lalani, M Wells

Department of Pathology and Laboratory Medicine

No abstract provided.


Two Separable Functional Domains Of Simian Virus 40 Large T Antigen: Carboxyl-Terminal Region Of Simian Virus 40 Large T Antigen Is Required For Efficient Capsid Protein Synthesis., Joanne Tornow, Maryellen Polvino-Bodnar, George Santangelo, Charles N. Cole Feb 1985

Two Separable Functional Domains Of Simian Virus 40 Large T Antigen: Carboxyl-Terminal Region Of Simian Virus 40 Large T Antigen Is Required For Efficient Capsid Protein Synthesis., Joanne Tornow, Maryellen Polvino-Bodnar, George Santangelo, Charles N. Cole

Dartmouth Scholarship

The carboxyl-terminal portion of simian virus 40 large T antigen is essential for productive infection of CV-1 and CV-1p green monkey kidney cells. Mutant dlA2459, lacking 14 base pairs at 0.193 map units, was positive for viral DNA replication, but unable to form plaques in CV-1p cells (J. Tornow and C.N. Cole, J. Virol. 47:487-494, 1983). In this report, the defect of dlA2459 is further defined. Simian virus 40 late mRNAs were transcribed, polyadenylated, spliced, and transported in dlA2459-infected cells, but the level of capsid proteins produced in infected CV-1 green monkey kidney cells was extremely low. dlA2459 large T …


Cyanonews (Vol. 1, No. 2, December 1985), Jeff Elhai Jan 1985

Cyanonews (Vol. 1, No. 2, December 1985), Jeff Elhai

CyanoNews

CyanoNews was a newsletter that served the cyanobacteriological community from 1985 to 2003, with content provided by readers (sort of a blog before there were blogs). The newsletter reported new findings from the lab, summaries of recent meetings (often provided by graduate students and post-docs entering the field), positions sought or available, life transitions, a compendium of recent cyanobacteria-related articles, and other items of interest to those who study cyanobacteria.


Cyanonews (Vol. 1, No. 1, July 1985), Jeff Elhai Jan 1985

Cyanonews (Vol. 1, No. 1, July 1985), Jeff Elhai

CyanoNews

CyanoNews was a newsletter that served the cyanobacteriological community from 1985 to 2003, with content provided by readers (sort of a blog before there were blogs). The newsletter reported new findings from the lab, summaries of recent meetings (often provided by graduate students and post-docs entering the field), positions sought or available, life transitions, a compendium of recent cyanobacteria-related articles, and other items of interest to those who study cyanobacteria.


Response Of A Nitrifying Biofilm To Copper, Denise Moldroski Mott Jan 1985

Response Of A Nitrifying Biofilm To Copper, Denise Moldroski Mott

Masters Theses

In pure cultures of Nitrosomonas, copper is known to cause a stimulation of nitrification at low levels (≤ 0.03 mg Cu+2/1) and an inhibition affect at higher levels (≥ 0.05 mg Cu+2/1). Nitrifying activated sludges are much more tolerant of copper showing only 75% inhibition at 150mg Cu+2/1. The purpose of this paper was to determine the copper sensitivity of a nitrifying biofilm grown in a continuous flow trickling filter system.

A continuous flow trickling filter system was built using limestone chips for the biofilm substrate. The biofilm was established from secondary effluent. …


Fecal Coliform Membrane Filtration Recovery Techniques, Pamela Rose Rinebold Jan 1985

Fecal Coliform Membrane Filtration Recovery Techniques, Pamela Rose Rinebold

Masters Theses

Researchers over the years have been trying to improve recovery techniques for fecal coliform bacteria. Improved techniques would provide better estimates of the number of fecal coliform bacteria as well as better estimates of fecal contamination with potential pathogenicity of food and water.

Stressed, but viable, fecal coliform bacteria if placed under the appropiate conditions, can recover, thus presenting the possibility of inadequate disinfection. Chlorine sanitization, as done in potable and wastewater treatment, is one such method of stressing bacteria.

Techniques of recovery were studied using presumably unstressed and chlorine stressed samples. Phase one of this study was the comparison …


A Comparison Of The Acidic Extracellular Polysaccharides From Rhizobium Trifolii Mutants Affected In Trifolium Repens Root Hair Curling, Brian Andrew Hanley Jan 1985

A Comparison Of The Acidic Extracellular Polysaccharides From Rhizobium Trifolii Mutants Affected In Trifolium Repens Root Hair Curling, Brian Andrew Hanley

Masters Theses

The compositions and sugar linkages of the acidic extracellular polysaccharide (EPS) from several Rhizobium trifolii mutants were compared. These mutants were derived from a wild type Rhizobium trifolii, ANU843, and are unable to cause normal root hair curling, Hac-, or nodulate clover, Nod-. Three of the mutants contain a Tn5 insertion in a 5.3 kb BglII fragment of the symbiotic plasmid (pSym). A fourth mutant is missing the pSym, which includes much of the 5.3 kb BglII fragment, both of these deletions result in Hac-Nod- phenotypes. When the 5.3 kb BglII fragment is cloned (pRT150) and reinserted into the …


Seasonal Responses Of Filtration Rates To Temperature, Oxygen Availability, And Particle Concentration Of The Freshwater Clam, Musculium Partumeium (Say), Albert J. Burky, Richard B. Benjamin, Denis G. Conover, Jennifer Detrick Jan 1985

Seasonal Responses Of Filtration Rates To Temperature, Oxygen Availability, And Particle Concentration Of The Freshwater Clam, Musculium Partumeium (Say), Albert J. Burky, Richard B. Benjamin, Denis G. Conover, Jennifer Detrick

Biology Faculty Publications

Seasonal filtration rates of a pond population of the freshwater pisidiid clam, Musculium par­tumeium (Say), were assessed by measuring the clearance of 2.02 µ.m latex beads from suspension and expressed in terms of FR = a(AFDW}b where FR = filtration rate (ml H20 · hr- 1 ) , AFDW = mg ash-free dry weight of a whole clam and "a" and "b" are constants. The a-values ( = FR of a 1-mg AFDW clam} vary seasonally with the highest rates corresponding to periods of maximum growth and reproduction in the spring and fall. Changes in "b" reflect the influence of …


Isolation And Characterization Of The Crossreactive Antigenic And Allergenic Components In Callistemon Citrinis And Melaleuca Quinquenervia Pollen By Immunochemical Methods, Brett E. Stanaland Jan 1985

Isolation And Characterization Of The Crossreactive Antigenic And Allergenic Components In Callistemon Citrinis And Melaleuca Quinquenervia Pollen By Immunochemical Methods, Brett E. Stanaland

Retrospective Theses and Dissertations

No abstract provided.


Partial Characterization Of The Extracellular Polysaccharides Produced By Mutants Of Rhizobium Leguminosarum And Rhizobium Trifolii, Lendell L. Cummins Jan 1985

Partial Characterization Of The Extracellular Polysaccharides Produced By Mutants Of Rhizobium Leguminosarum And Rhizobium Trifolii, Lendell L. Cummins

Masters Theses

Extracellular polysaccharides (EPS) are suspected to be involved in some aspect of the Rhizobium-legume symbiotic process. Extracellular polysaccharides produced by R. leguminosarum and R. trifolii mutants were isolated and partially characterized by gas chromatography, column chromatography, double diffusion, polyacrylamide gel electrophoresis, and immunoelectrophoresis.

The R. leguminosarum mutants, derived from strain 128C53, all are deficient in EPS production (exo-). Strain ANU54 is missing the symbiotic plasmid, while plasmid-containing strains ANU54 pJB5JI and ANU54 pBR1AN nodulate (nod+) peas and clover respectively, but do not fix nitrogen (fix-).

R. leguminosarum mutants produce an EPS that is similar to parental LPS in composition. …


Factors Affecting Germ Tube Formation In Candida Albicans, Walter A. Tatarowicz Jan 1985

Factors Affecting Germ Tube Formation In Candida Albicans, Walter A. Tatarowicz

Master's Theses

No abstract provided.


Observations On The Adherence Of Bacteroides Bivius To Female Genital Tract And Oral Epithelial Cells, Susan V. Meade Jan 1985

Observations On The Adherence Of Bacteroides Bivius To Female Genital Tract And Oral Epithelial Cells, Susan V. Meade

Master's Theses

No abstract provided.


Dissection Of Microphage Activation Using T Cell Hybridoma Derived Lymphokines, William S. Futch Jr. Jan 1985

Dissection Of Microphage Activation Using T Cell Hybridoma Derived Lymphokines, William S. Futch Jr.

Theses and Dissertations

Macrophage phenotype/function can be modulated by various T-cell lymphokines (LK). The alteration of macrophage phenotype is a result of LK concentration, duration of exposure, and the level of macrophage activation when obtained from in vivo sources through elicitation by either sterile irritants or immune cellular mechanisms. In order to dissect macrophage activation into discrete signals T cell hybridomas were constructed by fusing HAT sensitive BW5147 cells with nylon-wool purified, con A stimulated T cells. The resulting T cell hybrids were screened for their ability to: (a) protect macrophages from the cytopathic effect of Naegleria; (b) induce class II MHC gene …


Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson Dec 1984

Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson

Publications (WR)

The response to periodic desiccation of periphyton communities developed in eddy environments or in areas exposed to variable, direct current was examined. Algal communities were incubated on clay tiles for between 2 and 12 weeks in the Colorado River, directly below Hoover Dam from October, 1983 - January, 1984. Mean daily discharge from the dam decreased over this period. To assess the influence of these discharge changes on community dynamics, samples collected over the first 12 weeks of the investigation were compared to samples of the same age collected over the final 8 weeks.

The small diatom taxon Achnahthes spp …


A Restriction Analysis Of Klebsiella Pneumoniae Phage Sbs, Heidi A. Walters-Khan Aug 1984

A Restriction Analysis Of Klebsiella Pneumoniae Phage Sbs, Heidi A. Walters-Khan

Loma Linda University Electronic Theses, Dissertations & Projects

A Klebsiella phage was isolated from the San Bernardino sewage and its physiochemical properties analyzed. The present study found the density of the phage to be 1.44 g/ml, the burst size to be 10, and the phage had a latent period of 20-25 minutes. The DNA was found to be double stranded and linear. Its molecular weight was 41.66 + 0.72 kilobase pairs. The DNA was digested with a battery of endoncleases and partial restriction maps determined. The potential of the phage as a vector for Klebsiella is discussed in the text.


A Study Of The Mannitol Binding Protein Active Transport System And A Catabolite Repression Resistant Mutant In Pseudomonas Aeruginosa, Joseph Arthur Wolff Aug 1984

A Study Of The Mannitol Binding Protein Active Transport System And A Catabolite Repression Resistant Mutant In Pseudomonas Aeruginosa, Joseph Arthur Wolff

Masters Theses

Cold-shock extraction procedures were used for the efficient release of mannitol binding protein. Magnesium chloride and cold-shock released 92% of the total whole cell mannitol binding protein activity without release of detectable cytoplasmic marker protein glucose-6- phosphate dehydrogenase. Arsenate inhibited mannitol uptake to the same extent as azide. The simultaneous loss and gain of mannitol binding protein activity with mannitol uptake activity in mutants and reventants respectively, was consistant with periplasmic mannitol binding protein as a required component of mannitol uptake. A catabolite repression resistant mutant for mannitol uptake was isolated and described. This mutant, designated WEP-1, escaped catabolite repression …


Ca(Ii)-Calmodulin Regulation Of Fungal Dimorphism In Ceratocystis Ulmi, Ganapathy Muthukumar, Kenneth W. Nickerson Jul 1984

Ca(Ii)-Calmodulin Regulation Of Fungal Dimorphism In Ceratocystis Ulmi, Ganapathy Muthukumar, Kenneth W. Nickerson

Papers in Microbiology

We have shown that Ca(II) ions, ethylene glycol-bis(β-aminoethyl ether)- N,N-tetraacetic acid, LaCl3, and six known calmodulin inhibitors shift the yeast-mycelium dimorphic potential of Ceratocystis ulmi. Our data are consistent with the conclusions that Ca(II)-calmodulin interaction is necessary for mycelial growth in C. ulmi and that the absence of this interaction leads to the yeast phase.


The Effects Of Biological Response Modification And Diet On The Immune Respose Of Tumor-Bearing Mice, David Grant Lovell Jun 1984

The Effects Of Biological Response Modification And Diet On The Immune Respose Of Tumor-Bearing Mice, David Grant Lovell

Loma Linda University Electronic Theses, Dissertations & Projects

The effect that diet and other modifiers may have upon the immune system of BALB/c mice bearing tumor were studied, mice were injected s.c. with 106 herpes simplex virus Type 2- Adult male BALB/c transformed (H238) cells in the thigh causing a visible fibrosarcoma within 1-2 weeks. Mice were fed either a diet low in protein (milk) and low in fat (Diet 1), or another diet low in protein (wheat) and high in fat (Diet 8). Spleen cells were collected for assays of cytotoxic T-lynphocyte (CTL) and natural killer (NK) cell activity. At 3 weeks post-injection, a decrease in …