Organisms Commons^™

Seasonal Phytoplankton Assemblages Of Five Ephemeral Ponds In York County, Virginia, Michelle R. Kokolis

Biological Sciences Theses & Dissertations

Five ephemeral ponds were identified in and around the Grafton Ponds Natural Area Preserve, approximately 56 km north of the City of Norfolk, Virginia. These ponds, which are filled seasonally by precipitation and groundwater discharge, range from 0.1 ha to 2 ha in size and from 4 cm to 3 meters in depth. Ponds for the study were chosen based on variations in their size, depth, basin cover material, canopy openness, and historical inundation period. The purpose of this study is to relate differences in the phytoplankton assemblages to the physical and chemical characteristics of the ponds. All five ponds …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …

Effect Of Magnesium On The Production Of Scna And Scnr By Streptococcus Pyogenes, Strain Ff22, Laura E. Quinn

Biological Sciences Theses & Dissertations

The lantibiotic SA-FF22, produced by Streptococcus pyogenes strain FF22, was the first described antimicrobial peptide produced by a Streptococcus species. S. pyogenes is a group A Streptococcus responsible for such human illness as strep-throat, rheumatic fever, necrotizing fasciitis, endocarditis, and meningitis. Previous studies of SA-FF22 have shown that antimicrobial activity is lost in the presence of lmM magnesium. We hypothesize that the lack of SA-FF22 activity in the presence of magnesium is due to an absence of transcription of scnA, the gene encoding SA-FF22. The lack of transcriptional activation of scnA may be due to an absence of ScnR, a …

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 …

Characterization Of A PorosTm-Fumonisin B1 Affinity Column For Isolating Ceramide Synthase From Rat Liver, S. Jernigan, W. B. Melchior Jr., G. R. Jenkins, K. L. Rowland, D. W. Roberts, P. C. Howard, H. Tolleson

Journal of the Arkansas Academy of Science

Fumonisin B1 is a mycotoxin produced by fungi of the genus Fusarium, common pathogens of corn and other grain plants. Toxic effects associated with fumonisin B1 include equine leukoencephalomacia, porcine pulmonary edema, rat renal carcinoma, and murine hepatocellular carcinoma. Increased risk for esophageal cancer in humans has been epidemiologically associated with consumption of corn contaminated with Fusarium, suggesting that fumonisin B1 may be involved. The biological effects of fumonisin B1 exposure result primarily from disruption of de novo sphingolipid biosynthesis via inhibition of ceramide synthase. Exposure of animals or cultured cells to fumonisin B1 results in the characteristic accumulation of …

Disinfection Of Dentin By Intracanal Laser Irradiation: An In Vitro Model, Silvia Cristina Mafra Cecchini

Loma Linda University Electronic Theses, Dissertations & Projects

A possible cause for root canal failure is the persistence of bacteria that have colonized dentinal tubules. To reduce this risk and, if possible, to also shorten the time consuming endodontic therapy, new equipment and materials are constantly being introduced. The aim of the present investigation was to study the effect of disinfection of dentinal tubules by intracanal laser irradiation using an in vitro model. The groups irradiated by various lasers were compared with calcium hydroxide, a material frequently used as intracanal medication between appointments. Freshly extracted, intact bovine incisors were used. The root cementum was removed and the teeth …

Cytoplasmic Filament-Deficient Mutant Of Treponema Denticola Has Pleiotropic Defects, Jacques Izard, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

In Treponema denticola, a ribbon-like structure of cytoplasmic filaments spans the cytoplasm at all stages of the cell division process. Insertional inactivation was used as a first step to determine the function of the cytoplasmic filaments. A suicide plasmid was constructed that contained part of cfpA and a nonpolar erythromycin resistance cassette (ermF and ermAM) inserted near the beginning of the gene. The plasmid was electroporated into T. denticola, and double-crossover recombinants which had the chromosomal copy of cfpA insertionally inactivated were selected. Immunoblotting and electron microscopy confirmed the lack of cytoplasmic filaments. The mutant was further …

Pulse And Canola Frost Identification:The Back Pocket Guide, Craig White

Bulletins 4000 -

This field guide will help you identify the common symptoms of frost damage in pulse and canola crops. It also contains pictures of other plant symptoms often confused with frost damage in these crops.

Frost damage reduces crop yield and grain quality. Early identification of symptoms allows timely crop salvage decisions to be made.

Inspect pulse and canola crops between bud formation and during pod growth if right air temperature (recorded 1.2 m above ground) falls below 2 degrees celsius and there was a frost.

Check low lying, light coloured soil types and known frost prone areas first. Then check …

Molecular Evolution Of Insecticidal Spore-Forming Bacteria, John Pool

Honors Theses

Molecular methods are increasingly being used to determine the phylogeny of microorganisms. This research was intended to determine phylogenetic relationships for bacteria of the species Bacillus thuringiensis and other members of the Bacillus cereus group. Each strain was analyzed by its sasp-B gene sequence to determine its species classification and relation to other strains studied. Results of this study indicated that according to the sasp-B gene tree, the species Bacillus thuringiensis is a paraphyletic with respect to both Bacillus cereus and Bacillus anthracis. Some unexpected results and implications for species designations are also discussed.

Bulletin 4406a - Fungal Diseases Of Canola In Western Australia, Martin Barbetti, Ravjit Khangura

Bulletins 4000 -

GRDC - Grains Research & Development Corporation.

There has been dramatic growth in the canola industry in Western Australia, from 35,000 hectares in 1993 to 920,000 hectares in 1999. Along with this expansion in the area sown the incidence and severity of various fungal diseases have also increased, especially blackleg. This Bulletin describes the most important and most prevalent fungal diseases of canola in Western Australia.

Role Of KAtp Channels In Reduced Antinociceptive Effect Of Morphine In Streptozotocin-Induced Diabetic Mice, Vivek Sood, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The nociceptive effect was measured using withdrawal latency in tail flick test in mice rendered diabetic by administering streptozotocin (200 mg/kg, i.p.). The antinociceptive effect of morphine (4 and 8 mg/kg, s.c.) and cromakalim, a KATP channel opener, (0.3, 1 and 2 micrograms, i.c.v.) was significantly reduced in diabetic mice. Moreover, co-administration of cromakalim(0.3 microgram) did not alter the reduced antinociceptive effect of morphine(4 mg/kg) in diabetic mice. Spleenectomy in diabetic mice restored the decrease in antinociceptive effect of morphine and cromakalim. Multiple dose treatment with insulin to maintain euglycaemia for 3 days in diabetic mice prevented the decrease in …

Whole Genome Sequencing Of L.Monocytogenes And L.Innocua : A Basis For Comparative Genomics Of The Genus Listeria, Rachel Purcell

Theses

Listeria monocytogenes is a gram-positive, food-borne human and animal pathogen. L.innocua is a non-pathogenic species the most closely related to L. monocytogenes. Comparative genomics between a pathogenic and a closely related non-pathogenic species is a powerful approach for identifying genes or regions on the chromosome, which might be involved in virulence. Therefore whole genome sequencing of these two organisms was undertaken. The strategy used was based on a random approach combined with end-sequencing of a medium insert library for the finishing phase. Based on the available sequence data for these two species an in silico analysis for the presence of …

Effect Of Actinomycin D And Cycloheximide On Ischemic Preconditioning-Induced Delayed Cardioprotective Effect In Rats, Devinder Singh, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The present study was designed to investigate the effect of actinomycin D, a transcription inhibitor, and cycloheximide, a translation inhibitor, on the delayed cardioprotective effect of ischemic preconditioning. Left thoracotomy was performed in anaesthetized rats at 4th/5th intercostal space and polypropylene suture (5-0) was employed to occlude left common coronary artery. Ischemic preconditioning was produced by four episodes of 5 min of coronary artery occlusion followed by 5 min of reperfusion and thoracic cavity was sutured. Left thoracotomy was performed again after 24 hr of ischemic preconditioning and left coronary artery was occluded for 30 min followed by reperfusion for …

An Extracellular Protein Produced By Staphylococcus Hominis Strain Αm With Antimicrobial Activity Against Mycobacterium Spp, Sandra May Jacobsen

Biological Sciences Theses & Dissertations

The inhibitory activity exhibited by Staphylococcus hominis strain αM toward Mycobacterium species was examined. These studies included determining the conditions that maximized inhibitory agent production, analyzing characteristics of the agent, determining the time of agent production, ascertaining plasmid possession and the role of plasmids in the production of this inhibitory agent, and ascertaining the antimicrobial activity of other strains of S. hominis. On solid and in liquid media, S. hominis strain αM exhibits a unique inhibitory activity toward Mycobacterium species that is not demonstrated by Staphylococcus epidermidis or other S. hominis strains. Maximum agent production and recovery was …

Insertional Inactivation Of Treponema Denticola Tap1 Results In A Nonmotile Mutant With Elongated Flagellar Hooks, Ronald J. Limberger, Linda L. Slivienski, Jacques Izard, William A. Samsonoff

Department of Food Science and Technology: Faculty Publications

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription …

An Endophytic Fungus As A Source Of New Antifungal Compounds, Lisa Marie Jungbauer

Honors Theses, 1963-2015

Medical advances in society such as organ transplants, prolonged chemotherapy, and those that lengthen the lives of AIDS patients and the elderly increase the number of immunocompromised individuals(1). When the immune system is compromised, opportunistic fungi can flourish and become fatal. Current antifungal treatments are limited and often toxic(2,3). In addition, strains of fungi resistant to available antifungals are emerging(4,5). Fungi were selected as the source of potential new antifungal agents because fungal antagonism has been reported in most fungal ecosystems(6). Endophytic fungi, which inhabit the spaces between plant cells, are known producers of natural products and that assist plants …

Can Large Dsdna-Containing Viruses Provide Information About The Minimal Genome Size Required To Support Life?, James L. Van Etten

James Van Etten Publications

The genomes of a few viruses, such as Bacillus megaterium phage G (670 kb) and the chlorella viruses (330 to 380 kb), are larger than the predicted minimal genome size required to support life (ca. 320 kb). A comparison of the 256 proteins predicted to be required for life with the putative 376 proteins encoded by chlorella virus PBCV-1, as well as those encoded by other large viruses, indicates that viruses lack many of these “essential” genes. Consequently, it is unlikely that viruses will aid in determining the minimal number and types of genes required for life. However, viruses may …

Stachybotrys: Is Nevada At Risk?, Terrylynn C. Foley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Stachybotrys chartarum (atra) is a toxigenic fungus that is known to adversely impact the health of animals. Until recently, there have only been a few documented clinical reports linking Stachybotrys chartarum to human health effects. Scientists are increasingly convinced that Stachybotrys and its metabolites are responsible for several adverse health effects experienced by people all over the world, although conclusive proof has yet to be established. All the physical requirements needed for indoor Stachybotrys sporulation and growth is provided through water leaks (plumbing, roof or ceiling), flood events, nutrient sources (cellulose and nitrogen), pH, and temperature(23° - 28°C). Stachybotrys has …

Characterization Of Metal-Regulated Genes In Pseudomonas Fluorescens, Melanie Pearson

Honors Theses

One side effect of today's industrialized world is increased levels of heavy metals in the environment. Many of these metals are necessary for biological function as trace elements, but at higher concentrations are toxic. Other metals, such as cadmium, are not beneficial at any level, and have only deleterious effects on living organisms. Cadmium is primarily thought to interfere with normal biological function of proteins. Human exposure to cadmium appears to primarily damage the kidneys, but may also affect the liver, lungs, immune system, and central nervous system. Bacteria, however, have developed several methods for handling toxic heavy metals: cation …

A Pilot Study Testing A Proprietary Sealant For Plaque Reduction, Jennifer Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Enamel demineralization due to increased plaque accumulation is a well-recognized problem associated with fixed orthodontic appliances. The purpose of this study was to evaluate the efficacy of a proprietary product to be marketed by 3M Unitek for the reduction of plaque accumulation and thereby reduce enamel demineralization.

Sixty four bovine teeth were divided equally into an untreated control group and a group treated with the proprietary sealant product. Both groups were subsequently immersed in a Streptococcus mutans culture. Plaque deposits from each group were removed, suspended in trypticase soy broth, serially diluted, and plated on trypticase soy agar at 1, …

Development Of A Blocking Enzyme-Linked Immunosorbent Assay For Detection Of Serum Antibodies To O157 Antigen Of Escherichia Coli., W Laegreid, M Hoffman, J Keen, R Elder, J Kwang

Manuscripts, Articles, Book Chapters and Other Papers

The O157 antigen of Escherichia coli shares structural elements with lipopolysaccharide (LPS) antigens of other bacterial species, notably Brucella abortus and Yersinia enterocolitica 09, a fact that confounds the interpretation of assays for anti-O157 antibodies. To address this problem, a blocking enzyme-linked immunosorbent assay (bELISA) was designed with E. coli O157:H7 LPS as the antigen and a monoclonal antibody specific for E. coli O157, designated 13B3, as the competing antibody. The bELISA had equivalent sensitivity to, and significantly higher specificity than, the indirect ELISA (iELISA), detecting anti-O157 antibodies in sera from cattle experimentally inoculated with O157:H7. Only 13% of sera …

Methicillin Resistant Staphylococcus Aureus (Mrsa): Molecular Detection And Dna Fingerprinting, Leslie Cotter

Theses

Throughout the 1990s, the incidence of methicillin-resistant Staphylococcus aureus has increased in many health care areas including acute and chronic care facilities, outpatient clinics and in the community. Once introduced into a health care environment, this nosocomial pathogen can spread rapidly and as MRSA are resistant to multiple antibiotics, treatment is often difficult. Therefore effective infection control measures are required to prevent cross-infection and further spread of endemic strains.

In this study, a sensitive and specific triplex-PCR assay was designed for MRSA detection, wherein three genes, the methicillin resistance gene (mecA). femA and the extracellular thermonuclease gene (rmc) were simultaneously …

Let The Animals Live V. Hamat Gader, Mishael Cheshin, Theodor Or, Jacob Turkel

Translated Opinions

Facts: The petitioner, an organization for the protection of animal rights, petitioned the magistrate court to issue an injunction against the respondents, which would prohibit the show they presented, which included a battle between a man and an alligator. The magistrate court, holding that the battle in question constituted cruelty to animals, which was prohibited under section 2 of the Cruelty to Animals Law (Protection of Animals)-1994. The respondents appealed this order to the district court, which cancelled the injunction. The petitioners requested leave to appeal this decision to this Court.

Held: The Court held that the show in question …

Cellular Responses In Escherichia Coli To Lethal And Sublethal Doses Of Ozone, Indira Ruth Komanapalli

Loma Linda University Electronic Theses, Dissertations & Projects

Ozone is a major component of photochemical smog. High levels of this pollutant, sufficient to affect human health are found in many urban areas worldwide. Though limited studies in humans are supported by extensive findings from animal experiments, a difficulty in interpreting the results of these experiments has lead to an ambiguity on the biochemical mechanism of ozone toxicity. To elucidate the mechanism by which ozone causes cell damage and eventual cell death we conducted a comprehensive study using Escherichia coli K-12 as a model.

Studies on the comparative inactivation of bacteriophage lambda (λ), Escherichia coli, and Candida albicans …

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 …

Influence Of A Mycorrhizal Fungus And/Or Rhizobium On Growth And Biomass Partitioning Of Subterranean Clover Exposed To Ozone, Joseph E. Miller, Steven R. Shafer, Michele M. Schoeneberger, Walter A. Pursley, Stephanie J. Horton, Charles B. Davy

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

The influence of soilborne symbionts such as rhizobia or mycorrhizal fungi on plant response to ozone (O₃) has not been well defined. Leguminous plants in the field are infected by both types of organisms, which influence plant nutrition and growth. We studied the effects of infection with Rhizobium leguminosarum biovar trifolii and/or Gigaspora margarita on response of subterranean clover (Trifolium subterraneum L. cv Mt. Barker) to O₃. Exposures were conducted in greenhouse CSTR chambers using four O₃ concentrations [charcoal-filtered (CF), 50, 100, or 150 ppb; 6 h day^-1, 5 day wk^{-1 …}

An Analysis Of Two Tests For Diesel Contamination In The Environment When Considering The Impact On Hydrocarbon Degrading Bacteria, Chris Wedding

Mahurin Honors College Capstone Experience/Thesis Projects

No abstract provided.

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 …

In Vitro Plaque Formation On Orthodontic Resin Sealants, Leland W. Pack

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to examine in vitro plaque formation on sealant coated enamel. The plaque growth on different types of sealants placed on enamel was compared to each other and to an unsealed enamel control. The antimicrobial properties of sealants were also studied.

Sealant coated bovine enamel disks were immersed in a S. mutans culture medium for four days. The amount of bacterial plaque formation was quantified by removing the deposit, suspending it in solution with subsequent serial dilution. Aliquots of the dilutions were then spread on blood agar plates and incubated for 48 hours. The number …

Desmids (Conjugatophyceae) From Arkansas, Jennifer A. Akin, Richard L. Meyer

Journal of the Arkansas Academy of Science

No abstract provided.