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Environmental Microbiology and Microbial Ecology

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Articles 1 - 23 of 23

Full-Text Articles in Organismal Biological Physiology

Novel Microbial Guilds Implicated In N2o Reduction, Guang He Dec 2023

Novel Microbial Guilds Implicated In N2o Reduction, Guang He

Doctoral Dissertations

N2O is a long-recognized greenhouse gas (GHG) with potential in global warming and ozone depletion. Terrestrial ecosystems are a major source of N2O due to imbalanced N2O production and consumption. Soil pH is a chief modulating factor controlling net N2O emissions, and N2O consumption has been considered negligible under acidic conditions (pH <6). In this dissertation, we obtained solids-free cultures reducing N2O at pH 4.5. Furthermore, a co-culture (designated culture EV) comprising two interacting bacterial population was acquired via consecutive transfer in mineral salt medium. Integrated phenotypic, metagenomic and metabolomic analysis dictated that the Serratia population excreted certain …

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Discovering Novel Polyextremotolerant Fungi, And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin Carr Jul 2022

Discovering Novel Polyextremotolerant Fungi, And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin Carr

School of Biological Sciences: Dissertations, Theses, and Student Research

The ecological niche of polyextremotolerant fungi within oligotrophic ecosystems such as biological soil crusts has not yet been determined. These fungi persist in locations where nutrients are depleted while simultaneously surrounded by autotrophic microbes such as algae and cyanobacteria. Yet it has not been shown that they are engaging in any exchange of nutrients the way lichens do. However, there is seemingly no other way for these fungi to obtain vital nutrients, such as carbon or nitrogen, other than from these microbes. Here we have isolated polyextremotolerant fungi from cold desert biological soil crusts which are a microbial biofilm that …

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Parameter Estimation Using Nudging On The Logistic Growth Equation, Susan Rogowski May 2022

Parameter Estimation Using Nudging On The Logistic Growth Equation, Susan Rogowski

Biology and Medicine Through Mathematics Conference

No abstract provided.

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Taxonomic Microbiome Profiling And Abundance Patterns In The Cacao (Theobroma Cacao L.) Rhizosphere Treated With Arbuscular Mycorrhizal Fungi And Bamboo Biochar, Angelbert D. Cortes, Nelly S. Aggangan, Rina B. Opulencia Mar 2021

Taxonomic Microbiome Profiling And Abundance Patterns In The Cacao (Theobroma Cacao L.) Rhizosphere Treated With Arbuscular Mycorrhizal Fungi And Bamboo Biochar, Angelbert D. Cortes, Nelly S. Aggangan, Rina B. Opulencia

The Philippine Agricultural Scientist

Biochar and arbuscular mycorrhizal fungi (AMF) are agricultural interventions adopted by farmers to improve the growth of crops in nutrient-deficient acidic soil, which relatively influence the biological properties in the rhizosphere. This greenhouse study investigated the changes in prokaryotic diversity in the rhizosphere of cacao plants grown in acidic soil with AMF and bamboo biochar (BB) for 15 months under nursery conditions. Metagenomic analysis of the V3-V4 region of the 16S rRNA gene of the rhizosphere with AMF, 15% BB, and AMF + 15% BB revealed that the addition of AMF and BB reduced the sample's diversity, but the treatments …

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Growth Of Diatom Fistulifera Alcalina In Bacterial Co-Culture And Comparative Mitogenomics Of Fistulifera Species, Erwin David Berthold Mar 2021

Growth Of Diatom Fistulifera Alcalina In Bacterial Co-Culture And Comparative Mitogenomics Of Fistulifera Species, Erwin David Berthold

FIU Electronic Theses and Dissertations

Diatoms are excellent biological models of growth and intracellular oil generation. The productivity and compounds of diatoms, especially oils, support aquatic food chains and human medical and industrial needs. The qualities that made diatoms prolific producers, specifically diatom physiological features such as growth rates with intracellular lipid storage in alkaline environments, are however poorly understood. Another physiological aspect that remains unexplored is the effects of bacteria on the growth and lipid production of alkaliphilic diatoms. More studies, especially co-cultures, are needed for advances in diatom biology and strain performance for the algal biotechnological field. Besides physiology, diatom genetics using next-generation …

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Inhibition Of Biofilm Formation By The Synergistic Action Of Egcg-S And Antibiotics, Shrameeta Shinde, Lee Lee, Tinchun Chu Jan 2021

Inhibition Of Biofilm Formation By The Synergistic Action Of Egcg-S And Antibiotics, Shrameeta Shinde, Lee Lee, Tinchun Chu

Department of Biology Faculty Scholarship and Creative Works

Biofilm, a stress-induced physiological state, is an established means of antimicrobial tolerance. A perpetual increase in multidrug resistant (MDR) infections associated with high mortality and morbidity have been observed in healthcare settings. Multiple studies have indicated that the use of natural products can prevent bacterial growth. Recent studies in the field have identified that epigallocatechin gallate (EGCG), a green tea polyphenol, could disrupt bacterial biofilms. A modified lipid-soluble EGCG, epigallocatechin-3-gallate-stearate (EGCG-S), has enhanced the beneficial properties of green tea. This study focuses on utilizing EGCG-S as a novel synergistic agent with antibiotics to prevent or control biofilm. Different formulations of …

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Screening The Cultivable Cave Microbial Mats For The Production Of Antimicrobial Compounds And Antibiotic Resistance, Jerneja Ambrožič Avguštin, Patricia Petrič, Lejla Pašić Dec 2019

Screening The Cultivable Cave Microbial Mats For The Production Of Antimicrobial Compounds And Antibiotic Resistance, Jerneja Ambrožič Avguštin, Patricia Petrič, Lejla Pašić

International Journal of Speleology

The current work extends the phenotypic characterization of a bacterial culture collection obtained from white, yellow, grey or pink microbial cave wall colonies that are common in the caves of Slovenian Karst. We have determined antibiotic resistance to 22 natural and synthetic antibiotics in 69 isolates from the microbial mats. Thirty-eight isolates (52%) were resistant to 1-5 antibiotics; another 27 isolates (37%) were resistant to 6-10 antibiotics; and 7 isolates (0.1%) were resistant to 11-17 antibiotics. We screened for production of antimicrobial compounds by growing cave isolates on five different media and overlaying individual cultures with ten Gram-positive and Gram …

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Ultramicrobacteria Genome Database Project, Abdullah A. Salim, Tien Tran, Andrew Putt, Terry C. Hazen Apr 2019

Ultramicrobacteria Genome Database Project, Abdullah A. Salim, Tien Tran, Andrew Putt, Terry C. Hazen

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Ultramicrobacteria (UMB) are a largely uncultured, globally abundant, and metabolically active group of bacteria. UMB have cell diameters ≤0.3μm, cell volumes ≤0.1 μm3, and small streamlined genomes. Recent findings indicate that UMB aid in bioremediation and nutrient cycling, but future investigations and comprehension of current findings are skewed by highly variable nomenclature and a lack of databases for functional, genomic, geochemical, or spatial data specific to candidate UMB. We aim to develop a user-friendly open-access database of various UMB candidates linked to an open-access online map where researchers can gather genomic, spatial, and geochemical data. Our comprehensive review of literature …

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Evidence For The Priming Effect In Single Strain And Simplified Communities Of Estuarine Bacteria, Abigail Amina Edwards Dec 2017

Evidence For The Priming Effect In Single Strain And Simplified Communities Of Estuarine Bacteria, Abigail Amina Edwards

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Through their transformation of naturally occurring organic matter, coastal marine bacteria play an essential role in carbon cycling. A phenomenon termed the priming effect (PE) occurs when microbial communities remineralize recalcitrant organic matter faster in the presence of labile organic matter and may be prevalent in coastal systems. To understand how microbial community members interact to induce PE, it is essential to first understand the mechanisms underlying PE in single strains and simplified bacterial communities. The effect to which different concentrations and sources of labile carbon stimulated the production of bacterial biomass from riverine organic matter by two marine bacteria …

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Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis Jan 2016

Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis

Theses and Dissertations--Plant and Soil Sciences

Engineered nanomaterials (ENMs) have become ubiquitous in consumer products and industrial applications, and consequently the environment. Much of the environmentally released ENMs are expected to enter terrestrial ecosystems via land application of nano-enriched biosolids to agricultural fields. Among the organisms most likely to encounter nano-enriched biosolids are the key soil bacteria known as plant growth promoting rhizobacteria (PGPR). I reviewed what is known concerning the toxicological effects of ENMs to PGPR and observed the need for high-throughput methods to evaluate lethal and sublethal toxic responses of aerobic microbes. I addressed this issue by developing high-throughput microplate assays which allowed me …

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Isolation And Identification Of Bacterial Endosymbionts In The Brooding Brittle Star Amphipholis Squamata, Abbey Rose Tedford Jan 2016

Isolation And Identification Of Bacterial Endosymbionts In The Brooding Brittle Star Amphipholis Squamata, Abbey Rose Tedford

Honors Theses and Capstones

Symbiotic associations with subcuticular bacteria (SCB) have been identified and studied in numerous echinoderms, including the SCB of the brooding brittle star, Amphipholis squamata. These SCB, however, have not been studied using current next generation sequencing technologies. Previous studies on the SCB of A. squamata placed these bacteria in the genus Vibrio (γ-Proteobacteria), but subsequent studies suggested that the SCB are primarily composed of α-Proteobacteria. The present study examines the taxonomic composition of SCB associated with A. squamata from the Northwest Atlantic. DNA was extracted using a CTAB protocol and 16S rRNA sequences were amplified …

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A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe Oct 2015

A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe

Department of Biological Sciences Publications

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these …

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Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello Apr 2015

Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello

Master's Theses

The primary contributor to Vibrio fischeri aminopeptidase activity is aminopeptidase N, PepN. Colonization assays revealed the pepN mutant strain to be deficient at forming dense aggregates and populating the host’s light organ compared to wildtype within the first 12 hours of colonization; however the mutant competed normally at 24 hours. To address the role of PepN in colonization initiation and establish additional phenotypes for the pepN mutant strain, stress response and other physiological assays were employed. Marked differences were found between pepN mutant and wildtype strain in response to salinity, acidity, and antibiotic tolerance. This study has provided a foundation …

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Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood Dec 2014

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous …

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Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan Feb 2014

Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan

Department of Biological Sciences Publications

Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing …

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Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe Jan 2014

Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe

Department of Biological Sciences Publications

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron …

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Characterization Of Phycoerythrin Physiology In Low-Light Adapted Prochlorococcus Ecotypes, Kathryn H. Roache-Johnson Aug 2013

Characterization Of Phycoerythrin Physiology In Low-Light Adapted Prochlorococcus Ecotypes, Kathryn H. Roache-Johnson

Electronic Theses and Dissertations

The marine cyanobacteria Prochlorococcus and Synechococcus are the most abundant phototrophs in the oceans. They cohabit the oligotrophic ocean and thus have coevolved together, yet they have distinctly different methods for harvesting light. Synechococcus, like other cyanobacteria, possess phycobilisomes with various combinations of phycobiliproteins to capture wavelengths of light not otherwise available to chlorophyll. Prochlorococcus lack phycobilisomes and use divinyl chlorophyll b (Chl b2) as their primary accessory pigment to divinyl chlorophyll a (Chl a2) to capture light energy. In addition to the divinyl chlorophylls, Prochlorococcus has genes associated with the phycobiliprotein phycoerythrin (PE), the role of which is still …

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Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim Jan 2012

Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim

Papers in Microbiology

Farnesol has been best studied for its role in regulating fungal dimorphism. However, farnesol is also a lipid and in this review we analyze data relevant to farnesol’s function and synthesis from the perspective of farnesol and bacterial endotoxins acting as membrane active compounds. This analysis implicates the possible roles of: (1) endotoxins in the regulation of farnesol production by C. albicans; (2) farnesol in the interactions between C. albicans and the host during disseminated infections; and (3) ubiquinones in the mechanisms for unusually high resistance to farnesol by some C. albicans cell types. Finally we discuss the implications …

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Potential For Nitrogen Fixation And Nitrification In The Granite-Hosted Subsurface At Henderson Mine, Co, Elizabeth D. Swanner, Alexis S. Templeton Dec 2011

Potential For Nitrogen Fixation And Nitrification In The Granite-Hosted Subsurface At Henderson Mine, Co, Elizabeth D. Swanner, Alexis S. Templeton

Elizabeth D. Swanner

The existence of life in the deep terrestrial subsurface is established, yet few studies have investigated the origin of nitrogen that supports deep life. Previously, 16S rRNA gene surveys cataloged a diverse microbial community in subsurface fluids draining from boreholes 3000 feet deep at Henderson Mine, CO, USA (Sahl et al., 2008). The prior characterization of the fluid chemistry and microbial community forms the basis for the further investigation here of the source of NH4+. The reported fluid chemistry included N2, NH4+ (5–112 μM), NO2− (27–48 μM), and NO3− (17–72 μM). In this study, the correlation between low NH4+ concentrations …

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Structured Multiple Endosymbiosis Of Bacteria And Archaea In A Ciliate From Marine Sulfidic Sediments: A Survival Mechanism In Low Oxygen, Sulfidic Sediments?, Virginia P. Edgcomb, Edward R. Leadbetter, William A. Bourland, David Beaudoin, Joan M. Bernhard Mar 2011

Structured Multiple Endosymbiosis Of Bacteria And Archaea In A Ciliate From Marine Sulfidic Sediments: A Survival Mechanism In Low Oxygen, Sulfidic Sediments?, Virginia P. Edgcomb, Edward R. Leadbetter, William A. Bourland, David Beaudoin, Joan M. Bernhard

William Bourland

Marine micro-oxic to sulfidic environments are sites of intensive biogeochemical cycling and elemental sequestration, where prokaryotes are major driving forces mediating carbon, nitrogen, sulfur, phosphorus, and metal cycles, important from both biogeochemical and evolutionary perspectives. Associations between single-celled eukaryotes and bacteria and/or archaea are common in such habitats. Here we describe a ciliate common in the micro-oxic to anoxic, typically sulfidic, sediments of Santa Barbara Basin (CA, USA). The ciliate is 95% similar to Parduzcia orbis (18S rRNA). Transmission electron micrographs reveal clusters of at least three different endobiont types organized within membrane-bound sub-cellular regions. Catalyzed reporter deposition–fluorescent in situ …

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Letter From The Dean, Lalit Verma Jan 2009

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

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A Common Pattern Of Somite Cell Rotation In Three Species Of Pipidae, Shou-Yuan Fan, Rafael O. De Sá, Gary P. Radice Mar 2001

A Common Pattern Of Somite Cell Rotation In Three Species Of Pipidae, Shou-Yuan Fan, Rafael O. De Sá, Gary P. Radice

Biology Faculty Publications

During amphibian somitogenesis, presumptive myotome cells change shape from round or polygonal to elongated and aligned parallel to the notochord (for reviews see Radice, et al., 1989; Keller, 2000). Although the final orientation of myotomal cells is always axial, the movements that achieve this final arrangement can differ greatly between species. The simplest movement is that seen in Bombina variegata, Pelobates fuscus, and Bufo bufo (Brustis et al., 1976; Brustis, 1979; Kielbowna, 1981 ). In these anurans, after segmentation myotomal cells simply elongate along the embryo’s anteroposterior axis. The urodeles Ambystoma mexicanum and Pleurodeles waltl have a very different pattern; …

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A Comparative Study Of The Benthic Population In Weir Ponds Draining Watersheds Of The Fernow Experimental Forest, Parsons, West Virginia, Kevin Dwayne Brittingham Jan 1997

A Comparative Study Of The Benthic Population In Weir Ponds Draining Watersheds Of The Fernow Experimental Forest, Parsons, West Virginia, Kevin Dwayne Brittingham

Theses, Dissertations and Capstones

A study of the benthos of weir ponds draining watersheds of the Fernow Experimental Forest (FEF) was conducted in 1994-1995. The objectives of this study were: (1) to relate differences in weir pond faunas to watershed treatments on the FEF, and (2) to compare current weir pond faunas to those described in 1973 by Steve Harris. In 1971-1972, there were fewer invertebrates but greater taxa richness than in 1994-1995. Total density varied among weir pond and between studies with numbers in the 1971- 1972 study ranging from 26,168 to 79,259 individuals collected, while numbers in the 1994-1995 study raged from …

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