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Articles 61 - 90 of 92

Full-Text Articles in Organisms

The Family Rhabdoviridae: Mono- And Bipartite Negative-Sense Rna Viruses With Diverse Genome Organization And Common Evolutionary Origins, Ralf G. Dietzgen, Hideki Kondo, Michael M. Goodin, Gael Kurath, Nikos Vasilakis Jan 2017

The Family Rhabdoviridae: Mono- And Bipartite Negative-Sense Rna Viruses With Diverse Genome Organization And Common Evolutionary Origins, Ralf G. Dietzgen, Hideki Kondo, Michael M. Goodin, Gael Kurath, Nikos Vasilakis

Plant Pathology Faculty Publications

The family Rhabdoviridae consists of mostly enveloped, bullet-shaped or bacilliform viruses with a negative-sense, single-stranded RNA genome that infect vertebrates, invertebrates or plants. This ecological diversity is reflected by the diversity and complexity of their genomes. Five canonical structural protein genes are conserved in all rhabdoviruses, but may be overprinted, overlapped or interspersed with several novel and diverse accessory genes. This review gives an overview of the characteristics and diversity of rhabdoviruses, their taxonomic classification, replication mechanism, properties of classical rhabdoviruses such as rabies virus and rhabdoviruses with complex genomes, rhabdoviruses infecting aquatic species, and plant rhabdoviruses with both mono- …


Evaluation Of Flocculation, Sedimentation, And Filtration For Dewatering Of Scenedesmus Algae, Nicholas A. Rhea, Jack Groppo, Czarena Crofcheck Jan 2017

Evaluation Of Flocculation, Sedimentation, And Filtration For Dewatering Of Scenedesmus Algae, Nicholas A. Rhea, Jack Groppo, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algae can be used as a feedstock for agricultural fertilizers, livestock and poultry feeds, anaerobic digestion, and biofuel production. For each end product, the requirements for moisture content (or solids content) vary, such that a desirable water removal strategy needs to be adaptable to varying levels of water removal. Flocculation, sedimentation, and filtration were evaluated as possible strategies for thickening and dewatering of algae. The goal of this study was to validate that algae cells treated by such means could be processed by vacuum belt filters and to determine the conditions under which the solids content could be increased to …


Role Of Intracellular Growth During The Gastrointestinal Stage Of Listeria Monocytogenes Infection, Grant Steven Jones Jan 2017

Role Of Intracellular Growth During The Gastrointestinal Stage Of Listeria Monocytogenes Infection, Grant Steven Jones

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Listeria monocytogenes is a facultative intracellular bacterium that causes foodborne disease in humans. L. monocytogenes invade the gut mucosa and then disseminate, causing systemic infections associated with high mortality rates in immunocompromised individuals. It is unknown how L. monocytogenes traffic to the mesenteric lymph nodes, which represent an important bottleneck for systemic spread. In addition, little is known about the gastrointestinal stage of infection due to the general resistance of mice to oral infection with L. monocytogenes. Our laboratory developed a novel foodborne mouse model of listeriosis utilizing a murinized strain of L. monocytogenes to investigate the gastrointestinal stage …


The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson Jul 2016

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson

Biosystems and Agricultural Engineering Faculty Publications

Phanerochaete chrysosporium treatment is less effective as a biological pretreatment on feedstock with larger particle sizes. We hypothesized that the improved effectiveness of the pretreatment when smaller particle sizes are used may be due to the inherently higher bulk density with smaller particle sizes. The effects of substrate bulk density and particle size on the efficacy of P. chrysosporium pretreatment of switchgrass (Panicum virgatum) was tested experimentally. Phanerochaete chrysosporium was grown on senesced switchgrass (2 different particle sizes) with various bulk densities. In all treatments, the fungal-pretreated samples released more glucose during enzymatic saccharification than the control sample. …


A Pan-Dengue Virus Reverse Transcription-Insulated Isothermal Pcr Assay Intended For Point-Of-Need Diagnosis Of Dengue Virus Infection By Use Of The Pockit Nucleic Acid Analyzer, Yun Young Go, R. P. V. Jayanthe Rajapakse, Senanayake A. M. Kularatne, Pei-Yu Alison Lee, Keun Bon Ku, Sangwoo Nam, Pin-Hsing Chou, Yun-Long Tsai, Yu-Lun Liu, Hsiao-Fen Grace Chang, Hwa-Tang Thomas Wang, Udeni B. R. Balasuriya Jun 2016

A Pan-Dengue Virus Reverse Transcription-Insulated Isothermal Pcr Assay Intended For Point-Of-Need Diagnosis Of Dengue Virus Infection By Use Of The Pockit Nucleic Acid Analyzer, Yun Young Go, R. P. V. Jayanthe Rajapakse, Senanayake A. M. Kularatne, Pei-Yu Alison Lee, Keun Bon Ku, Sangwoo Nam, Pin-Hsing Chou, Yun-Long Tsai, Yu-Lun Liu, Hsiao-Fen Grace Chang, Hwa-Tang Thomas Wang, Udeni B. R. Balasuriya

Maxwell H. Gluck Equine Research Center Faculty Publications

Dengue virus (DENV) infection is considered a major public health problem in developing tropical countries where the virus is endemic and continues to cause major disease outbreaks every year. Here, we describe the development of a novel, inexpensive, and user-friendly diagnostic assay based on a reverse transcription-insulated isothermal PCR (RT-iiPCR) method for the detection of all four serotypes of DENV in clinical samples. The diagnostic performance of the newly established pan-DENV RT-iiPCR assay targeting a conserved 3′ untranslated region of the viral genome was evaluated. The limit of detection with a 95% confidence was estimated to be 10 copies of …


Peptidomimetic Small Molecules Disrupt Type Iv Secretion System Activity In Diverse Bacterial Pathogens, Carrie L. Shaffer, James A.D. Good, Santosh Kumar, K. Syam Krishnan, Jennifer A. Gaddy, John T. Loh, Joseph Chappell, Fredrik Almqvist, Timothy L. Cover, Maria Hadjifrangiskou Apr 2016

Peptidomimetic Small Molecules Disrupt Type Iv Secretion System Activity In Diverse Bacterial Pathogens, Carrie L. Shaffer, James A.D. Good, Santosh Kumar, K. Syam Krishnan, Jennifer A. Gaddy, John T. Loh, Joseph Chappell, Fredrik Almqvist, Timothy L. Cover, Maria Hadjifrangiskou

Pharmaceutical Sciences Faculty Publications

Bacteria utilize complex type IV secretion systems (T4SSs) to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85) that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA) and peptidoglycan into gastric epithelial cells. In …


Cell-Free And Cell-Based Approaches To Explore The Roles Of Host Membranes And Lipids In The Formation Of Viral Replication Compartment Induced By Tombusviruses, Peter D. Nagy, Judit Pogany, Kai Xu Mar 2016

Cell-Free And Cell-Based Approaches To Explore The Roles Of Host Membranes And Lipids In The Formation Of Viral Replication Compartment Induced By Tombusviruses, Peter D. Nagy, Judit Pogany, Kai Xu

Plant Pathology Faculty Publications

Plant positive strand RNA viruses are intracellular infectious agents that take advantage of cellular lipids and membranes to support replication and protect viral RNA from degradation by host antiviral responses. In this review, we discuss how Tomato bushy stunt virus (TBSV) co-opts lipid transfer proteins and modulates lipid metabolism and transport to facilitate the assembly of the membrane-bound viral replicase complexes within intricate replication compartments. Identification and characterization of the proviral roles of specific lipids and proteins involved in lipid metabolism based on results from yeast (Saccharomyces cerevisiae) model host and cell-free approaches are discussed. The review also …


Graphene Oxide Quantum Dots Covalently Functionalized Pvdf Membrane With Significantly-Enhanced Bactericidal And Antibiofouling Performances, Zhiping Zeng, Dingshan Yu, Ziming He, Jing Liu, Fang-Xing Xiao, Yan Zhang, Rong Wang, Dibakar Bhattacharyya, Timothy Thatt Yang Tan Feb 2016

Graphene Oxide Quantum Dots Covalently Functionalized Pvdf Membrane With Significantly-Enhanced Bactericidal And Antibiofouling Performances, Zhiping Zeng, Dingshan Yu, Ziming He, Jing Liu, Fang-Xing Xiao, Yan Zhang, Rong Wang, Dibakar Bhattacharyya, Timothy Thatt Yang Tan

Chemical and Materials Engineering Faculty Publications

Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and …


Chronic Pancreatitis, Pain, And Anxiety In An Alcohol And High Fat Mouse Model, Tiffanie Clinkinbeard Jan 2016

Chronic Pancreatitis, Pain, And Anxiety In An Alcohol And High Fat Mouse Model, Tiffanie Clinkinbeard

Theses and Dissertations--Gerontology

Homeodynamic space (HDS) shrinks as vulnerability increases with aging and repeated damage to the cells. HDS is lost in alcoholic pancreatitis patients due to overconsumption of alcohol, smoking, and high fat diets. Etiologically relevant animal models for study of chronic pancreatitis (CP) are needed. In order to begin filling this gap a central purpose of this dissertation research was to examine relationships between the alcohol and high fat diet (AHF) and pancreatitis with attention to hypersensitivity and anxiety-like behaviors. The AHF diet induced pancreatitis described here etiologically mimics human risk factors of AHF consumption for advancement to alcoholic CP.

In …


In Vitro Activity Of Polymyxin B And Meropenem Alone And In Combination Against Carbapenem-Resistant Enterobacteriaceae, Brandon T. Kulengowski Jan 2016

In Vitro Activity Of Polymyxin B And Meropenem Alone And In Combination Against Carbapenem-Resistant Enterobacteriaceae, Brandon T. Kulengowski

Theses and Dissertations--Pharmacy

Background: Infections caused by carbapenem-resistant Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae are among the most urgent threats of the infectious disease realm. The incidence of these infections has only been increasing over the years and due to very limited treatment options, mortality is estimated at about 50%.

Methods: To evaluate the in vitro activity of meropenem and polymyxin B against carbapenem-resistant Enterobacteriaceae, antimicrobial susceptibility testing and time-kill studies were performed on K. pneumoniae clinical isolates representing a wide range of meropenem resistance (MICs 4 – 128 mg/L).

Results: Regrowth was observed at clinically relevant concentrations of meropenem alone …


Impact Of Starch Source On Equine Hindgut Microbial Ecology, Brittany Elizabeth Davis Harlow Jan 2015

Impact Of Starch Source On Equine Hindgut Microbial Ecology, Brittany Elizabeth Davis Harlow

Theses and Dissertations--Animal and Food Sciences

Grain inclusion in equine diets can allow starch to reach the hindgut where bacteria compete for the substrate. The hypothesis was that starch introduction would cause a source-dependent press disturbance in equine fecal microflora. Fecal cell suspensions were prepared by differential centrifugation and re-suspension in media with ground corn, oats or wheat. At 24 h, corn had more amylolytics and Group D Gram-positive cocci (GPC), and fewer lactate-utilizing (LU) bacteria and lactobacilli than oats, with wheat being intermediate. Predominant amylolytics were identified by their 16S RNA gene sequence as Enterococcus faecalis (corn, wheat) and Streptococcus bovis (oats). In an in …


First Proof Of Concept Of Sustainable Metabolite Production From High Solids Fermentation Of Lignocellulosic Biomass Using A Bacterial Co-Culture And Cycling Flush System, Wanying Yao, Sue E. Nokes Dec 2014

First Proof Of Concept Of Sustainable Metabolite Production From High Solids Fermentation Of Lignocellulosic Biomass Using A Bacterial Co-Culture And Cycling Flush System, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

To improve the lignocellulose conversion for ABE in high solids fermentation, this study explored the feasibility of cycling the process through the cellulolytic or/and solventogenic phases via intermittent flushing of the fermentation media. Five different flushing strategies (varying medium ingredients, inoculum supplement and cycling through phases) were investigated. Flushing regularly throughout the cellulolytic phase is necessary because re-incubation at 65 °C significantly improved glucose availability by at least 6-fold. The solvents accumulation was increased by 4-fold using corn stover (3-fold using miscanthus) over that produced by flushing only through the solventogenic phase. In addition, cycling process was simplified by re-incubating …


Lipid Extraction From Scenedesmus Sp. Microalgae For Biodiesel Production Using Hot Compressed Hexane, Hee-Yong Shin, Jae-Hun Ryu, Seong-Youl Bae, Czarena L. Crofcheck, Mark Crocker Aug 2014

Lipid Extraction From Scenedesmus Sp. Microalgae For Biodiesel Production Using Hot Compressed Hexane, Hee-Yong Shin, Jae-Hun Ryu, Seong-Youl Bae, Czarena L. Crofcheck, Mark Crocker

Center for Applied Energy Research Faculty and Staff Publications

Lipid extraction from Scenedesmus sp. microalgae using hot compressed hexane (HCH) was investigated. Extraction performance was evaluated near the critical point of hexane and was compared with that of hexane extraction performed at room temperature and pressure, and the Bligh and Dyer extraction method. Experimental data showed that HCH significantly improves the lipid yield and rate of lipid extraction compared to the use of hexane at ambient conditions. High yields of biodiesel-convertible lipid fractions were rapidly achieved at the critical point of hexane, at a level comparable to that of the Bligh and Dyer method.


Co2 Recycling Using Microalgae For The Production Of Fuels, Michael H. Wilson, John Groppo, Andrew Placido, S. Graham, S. A. Morton Iii, Eduardo Santillan-Jimenez, Aubrey Shea, Mark Crocker, Czarena Crofcheck, Rodney Andrews Mar 2014

Co2 Recycling Using Microalgae For The Production Of Fuels, Michael H. Wilson, John Groppo, Andrew Placido, S. Graham, S. A. Morton Iii, Eduardo Santillan-Jimenez, Aubrey Shea, Mark Crocker, Czarena Crofcheck, Rodney Andrews

Center for Applied Energy Research Faculty and Staff Publications

CO2 capture and recycle using microalgae was demonstrated at a coal-fired power plant (Duke Energy’s East Bend Station, Kentucky). Using an in-house designed closed loop, vertical tube photobioreactor, Scenedesmus acutus was cultured using flue gas as the CO2 source. Algae productivity of 39 g/(m2 day) in June–July was achieved at significant scale (18,000 L), while average daily productivity slightly in excess of 10 g/(m2 day) was demonstrated in the month of December. A protocol for low-cost algae harvesting and dewatering was developed, and the conversion of algal lipids—extracted from the harvested biomass—to diesel-range hydrocarbons via catalytic …


Phanerochaete Chrysosporium Pretreatment Of Biomass To Enhance Solvent Production In Subsequent Bacterial Solid-Substrate Cultivation, Wanying Yao, Sue E. Nokes Mar 2014

Phanerochaete Chrysosporium Pretreatment Of Biomass To Enhance Solvent Production In Subsequent Bacterial Solid-Substrate Cultivation, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

This study investigated pretreatment of corn stover using solid substrate cultivation (SSC) of Phanerochaete chrysosporium (P. chrysosporium) to improve subsequent accessibility to cellulose. Thereafter, Clostridium thermocellum (C. thermocellum) was directly inoculated onto the pretreated biomass to accomplish hydrolysis, followed by solventogenesis by introducing Clostridium beijerinckii (C. beijerinckii).

An enzyme suite containing laccase, lignin peroxidase and manganese peroxidase activity was detected during the cultivation of P. chrysosporium on corn stover within 288 h at an initial moisture content 𝓌H2O = 80% (mass of water/total mass). Incubation factors, such as substrate moisture content and cultivation …


Pretreatment Of Scenedesmus Sp. Biomass As A Potential Anaerobic Digestion Substrate, Xinyi E, Czarena Crofcheck Jan 2014

Pretreatment Of Scenedesmus Sp. Biomass As A Potential Anaerobic Digestion Substrate, Xinyi E, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algal biomass can be a potential substrate for anaerobic digestion. However, raw algae cells show a resistance to biological degradation, resulting in a slower methane production rate. Varying thermal and chemical pretreatments of algal biomass were investigated in an attempt to increase soluble organic matter (SOM) yield, which would result in enhanced methane production during subsequent anaerobic digestion. Scenedesmus sp. was harvested using three different procedures: with flocculation, with flocculation and drying, and without flocculation or drying. For all pretreatments and algae types, fluorescence micrographs were obtained to visually confirm the degradation of the algal cell walls. A complete 2 …


Listeria Monocytogenes Can Utilize Both M Cell Transcytosis And Inla-Mediated Uptake To Cross The Epithelial Barrier Of The Intestine During An Oral Infection Model Of Listeriosis, Hilary Denney Jan 2014

Listeria Monocytogenes Can Utilize Both M Cell Transcytosis And Inla-Mediated Uptake To Cross The Epithelial Barrier Of The Intestine During An Oral Infection Model Of Listeriosis, Hilary Denney

Theses and Dissertations--Medical Sciences

The invasive pathways, InlA- and InB-mediated uptake and M cell transcytosis, that Listeria monocytogenes uses to invade the intestine have mainly been studied using infection models that do not truly replicate what occurs during a natural infection. Recently, our lab has developed an oral infection model that is more physiolocally relevant to what occurs during food borne listeriosis. We have sought to evaluate the relative roles of the previously defined invasive pathways, in our oral model of infection. We have done this by utilizing an InlAmCG Lm strain that is able to bind murine E-cadherin, knockout Lm strains, ΔinlA Lm …


Influence Of Media Composition On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus Utilized For Co2 Mitigation, Czarena L. Crofcheck, Xinyi E, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews Jun 2013

Influence Of Media Composition On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus Utilized For Co2 Mitigation, Czarena L. Crofcheck, Xinyi E, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews

Biosystems and Agricultural Engineering Faculty Publications

Atmospheric carbon dioxide levels have increased since the industrial revolution due to increasing combustion of fossil fuels. One possible CO2 mitigation strategy is the use of microalgae for mitigation of CO2. This paper focuses on the influence of media composition on the growth rate of two microalgae strains, Chlorella vulgaris and Scenedesmus actus. A KNO3 based medium was found to work better for Chlorella, while a urea based equivalent worked better for Scenedesmus. The urea based media investigated here resulted in growth similar to that found with previously reported KNO3 based media. …


Influence Of Flue Gas Components On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus, Czarena Crofcheck, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews Jan 2013

Influence Of Flue Gas Components On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus, Czarena Crofcheck, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews

Biosystems and Agricultural Engineering Faculty Publications

Atmospheric carbon dioxide levels have increased since the industrial revolution due to the increase in combustion of fossil fuels. One possible alternative strategy is the use of microalgae for CO2 capture and recycling. Major components in coal-derived flue gas that may accumulate and effect algae growth include both sulfur oxides and fly ash. However, in practical application, sulfur oxides will be converted quickly to the acid product (H2SO4) in the aerobic aqueous conditions of algae cultivation. In this article, the influence of elevated H2SO4 levels and the presence of coal-derived fly ash …


Effects Of Intranasally Administered Dnsp-11 On The Central Dopamine System Of Normal And Parkinsonian Fischer 344 Rats, James H. Sonne Jan 2013

Effects Of Intranasally Administered Dnsp-11 On The Central Dopamine System Of Normal And Parkinsonian Fischer 344 Rats, James H. Sonne

Theses and Dissertations--Neuroscience

Due to the blood-brain barrier, delivery of many drugs to the brain has required intracranial surgery which is prone to complication. Here we show that Dopamine Neuron Stimulating Peptide 11 (DNSP-11), following non-invasive intranasal administration, protects dopaminergic neurons from a lesion model of Parkinson’s disease in the rat. A significant and dose-dependent increase in an index of dopamine turnover (the ratio of DOPAC to dopamine) was observed in the striatum of normal young adult Fischer 344 rats by whole-tissue neurochemistry compared to vehicle administered controls.

Among animals challenged with a moderate, unilateral 6-hydroxy-dopamine (6-OHDA) lesion of the substantia nigra, those …


Submerged And Solid-State Phytase Fermentation By Aspergillus Niger: Effects Of Agitation And Medium Viscosity On Phytase Production, Fungal Morphology And Inoculum Performance, Maria Papagianni, Sue E. Nokes, Keith Filer Jan 2001

Submerged And Solid-State Phytase Fermentation By Aspergillus Niger: Effects Of Agitation And Medium Viscosity On Phytase Production, Fungal Morphology And Inoculum Performance, Maria Papagianni, Sue E. Nokes, Keith Filer

Biosystems and Agricultural Engineering Faculty Publications

Qualitative relationships between agitation levels and medium viscosity, Aspergillus niger morphology and phytase production were investigated in submerged and solid-state fermentations. Overall phytase production increased with increasing shaker speeds from 150 to 300 rpm, although specific growth rates and phytase production rates were higher at 150 rpm for 72 h from inoculation. Fungal morphology was greatly influenced by agitation with the morphological forms of small pellets and entangled mycelia predominating at 150 rpm, while the free filamentous form was obtained at 300 rpm. Upon inoculation of SSF, increased productivities were obtained from inocula grown at 150 rpm. A shift towards …


Indicator Bacteria Concentrations Of Two Northwest Arkansas Streams In Relation To Flow And Season, Dwayne R. Edwards, Mark S. Coyne, Tommy C. Daniel, P. F. Vendrell, J. F. Murdoch, P. A. Moore Jr. Jan 1997

Indicator Bacteria Concentrations Of Two Northwest Arkansas Streams In Relation To Flow And Season, Dwayne R. Edwards, Mark S. Coyne, Tommy C. Daniel, P. F. Vendrell, J. F. Murdoch, P. A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Concentrations of indicator bacteria such as fecal coliform (FC) and fecal streptococcus (FS) are often used to assess the suitability of waters for their intended use(s) and to allocate resources for water quality improvement measures. There is evidence, however, that concentrations of FC and FS can be influenced by variables such as season and flow rate during sampling, which could lead to biased results. The objective of this study was to assess the impacts of season and flow rate on concentrations of FC and FS. Fecal indicator bacteria concentrations were measured for approximately three years at five sites on two …


Metal-Resistance Genetically Engineered Bacteria, Sylvia Daunert, Donna Scott, Sridhar Ramanathan Jun 1996

Metal-Resistance Genetically Engineered Bacteria, Sylvia Daunert, Donna Scott, Sridhar Ramanathan

KWRRI Research Reports

Bacterial-based electrochemical and optical sensing systems that respond in a highly selective and sensitive manner to antimonite and arsenite have been developed. This was accomplished by using genetically engineered bacteria bearing one of two plasmids constructed for our studies. The first plasmid, pBGD23, contains the operator/promoter region (O/P) and the gene of the ArsR protein from the ars operon upstream from the β-galactosidase gene. In the absence of antimonite/arsenite, ArsR binds to the 0/P site and prevents the transcription of the genes for ArsR and β-galactosidase, thus blocking expression of these proteins. When antimonite or arsenite is present in the …


Movement Of Bacteria Through Macropores To Ground Water, M. Scott Smith, Grant W. Thomas, Robert E. White Jun 1983

Movement Of Bacteria Through Macropores To Ground Water, M. Scott Smith, Grant W. Thomas, Robert E. White

KWRRI Research Reports

Effects of soil type, flow rate, antecedent soil moisture and other factors on transport of E. coli through soils was measured on disturbed and intact columns 20 cm in diameter by 25 to 30 cm in depth. Added E. coli were distinguished from indigenous microbes using an antibiotic resistance marker. Transport of Cl- and 3H2O was also measured. Up to 96 percent of the bacteria irrigated onto the surface of intact columns were recovered in the effluent. Soil structure appeared to be related to the extent of transport. Columns prepared from mixed, repacked soil were much …


A Study Of Naturally Occurring Algicides Produced By Freshwater Algae, Denny O. Harris, Harry D. Caldwell Dec 1974

A Study Of Naturally Occurring Algicides Produced By Freshwater Algae, Denny O. Harris, Harry D. Caldwell

KWRRI Research Reports

The mode of action of the algicide produced by Pandorina morum was examined by exposing Volvox globator and isolates spinach chloroplasts to a partially purified algicide preparation. Oxygen evolution of Volvox, whole chloroplasts and broken chloroplasts (minus the Calvin cycle),was reduced indicating that the algicide inhibits the light reactions of photosynthesis. Oxygen evolution studies of other Volvocaceae confirmed the observation that Pandorina morum is not significantly influenced by its own inhibitor. Molecular weight approximation by gel filtration established that the inhibitor has a low molecular weight (probably below 100 mw). Field studies indicate that this algicide has tremendous potential as …


Metabolic Capabilities Of Sulfur Oxidizing Bacteria And Their Role In Water Pollution, M. I. H. Aleem Sep 1974

Metabolic Capabilities Of Sulfur Oxidizing Bacteria And Their Role In Water Pollution, M. I. H. Aleem

KWRRI Research Reports

This report describes investigations into the physiology of microorganisms that are commonly involved in the oxidation of inorganic sulfur compounds. The metabolic activities of these bacteria play a potent role in several fields of economic importance such as strip mining operations, water pollution, corrosion, metallurgy, petroleum technology and soil fertility processes.

The oxidation of inorganic sulfur compounds was studied in the chemolithotrophs Thiobacillus denitrificans, Thiobacillus A2, Thiobacillus neapolitanus, and a photolithotroph Rhodopseudomonas palustris. Cell suspensions from all of the thiobacilli catalyzed completely the oxidation of sulfide, thiosulfate, and sulfite to sulfate. The oxidation of thiosulfate in R. palustris …


A Study Of Water-Soluble Inhibitory Compounds (Algicides) Produced By Fresh-Water Algae, Denny O. Harris, Manhar C. Parekh Nov 1973

A Study Of Water-Soluble Inhibitory Compounds (Algicides) Produced By Fresh-Water Algae, Denny O. Harris, Manhar C. Parekh

KWRRI Research Reports

A complex system of growth inhibitors was observed in the green algae (Volvocaceae). Inhibitors were found in the culture filtrates of some genera which limit their own growth (autoinhibitors) while others in the family produce substances which check the growth of other genera (heteroinhibitors). These inhibitors were destroyed by autoclaving. It was decided that Pandorina morum, which produced the strongest inhibitor and Volvox tertius, the most sensitive to the inhibitor would make an excellent model system for a study of the chemical and physical properties of these naturally occurring algicides. The algicide could be removed from actively growing cultures about …


Carbon And Nitrogen As Regulators Of Algal Growth In Treated Sewage, Edward G. Foree, Charles Reece Scroggin Mar 1972

Carbon And Nitrogen As Regulators Of Algal Growth In Treated Sewage, Edward G. Foree, Charles Reece Scroggin

KWRRI Research Reports

Continuous flow algal cultures were grown under three different growth conditions using secondary sewage treatment plant effluent as the growth medium. The only variable within each run was the hydraulic residence time. The concentrations of growth regulating nutrients were varied between the runs so comparisons of the algal mass, composition, nutrient uptake, and genera could be made. The importance of CO2 availability for algal growth was also studied. A kinetic theory which based algal growth on cellular nutrient concentration was verified. The second phase of the study was a batch culture study in which the same growth medium was …


Factors Regulating The Growth Of Algae In Continuous Culture In Diluted Secondary Sewage Treatment Plant Effluent And Subsequent Biodegradability, Edward G. Foree, Caroline P. Wade Jan 1972

Factors Regulating The Growth Of Algae In Continuous Culture In Diluted Secondary Sewage Treatment Plant Effluent And Subsequent Biodegradability, Edward G. Foree, Caroline P. Wade

KWRRI Research Reports

Heterogeneous algal cultures were grown in laboratory continuous culture in continuous flow, completely mixed chemostats in secondary sewage treatment plant effluent diluted to give an ammonia nitrogen concentration of 10 mg/1. Variables were lighting, pH, carbon dioxide availability, and hydraulic residence time.

Optimum growth occurred under pH 7.0, excess CO2, and continuous lighting conditions. The availability of artificially supplied excess CO2 greatly increased the mass (standing crop) at steady-state over that produced under otherwise identical conditions for all residence times studied. For the case of excess CO2 availability, the nitrogen concentration in the algal cells regulated …


Metabolic Role Of Sulfates And Sulfides Producing Bacteria In Pollution Of Waters, M. I. H. Aleem Dec 1971

Metabolic Role Of Sulfates And Sulfides Producing Bacteria In Pollution Of Waters, M. I. H. Aleem

KWRRI Research Reports

Cytochrome transport particles from Nitrobacter catalyzed nitrite, ascorbate as well as NADH oxidation with concomitant phosphate esterification yielding P/0 ratios of 1.0, 0.6 and 2.0 respectively. Phosphorylation coupled to nitrite oxidation was not effected by rotenone, amytal or antimycin while 50 and 70% inhibition of the NADH-linked phosphorylation was observed in the presence of HOQNO and rotenone respectively. Cell-free extracts from Nitrobacter also catalyzed an energy-dependent reduction of NAD+ by nitrite. The reduction of cytochrome c by NŌ2 was energy-dependent which involved the reversal of electrons from cytochrome a1. The subsequent energy-linked reduction of the flavoproteins …