Microbiology Commons^™

Characterization Of The Poxab Operon Encoding A Class D Carbapenemase In Pseudomonas Aeruginosa,, Diansy Zincke

FIU Electronic Theses and Dissertations

Pseudomonas aeruginosa is a dreaded opportunistic pathogen that causes severe and often intractable infections in immunocompromised and critically ill patients. This bacterium is also the primary cause of fatal lung infections in patients with cystic fibrosis and a leading nosocomial pathogen responsible for nearly 10% of all hospital-acquired infections. P. aeruginosa is intrinsically recalcitrant to most classes of antibiotics and has the ability to acquire additional resistance during treatment. In particular, resistance to the widely used β-lactam antibiotics is frequently mediated by the expression of AmpC, a chromosomally encoded β-lactamase that is ubiquitously found in P. aeruginosa strains. This dissertation …

Changes Of Soil Biogeochemistry Under Native And Exotic Plants Species, Yujie Hua

FIU Electronic Theses and Dissertations

Invasive plant species are major threats to the biodiversity and ecosystem stability. The purpose of this study is to understand the impacts of invasive plants on soil nutrient cycling and ecological functions. Soil samples were collected from rhizosphere and non-rhizosphere of both native and exotic plants from three genera, Lantana, Ficus and Schinus, at Tree Tops Park in South Florida, USA. Experimental results showed that the cultivable bacterial population in the soil under Brazilian pepper (invasive Schinus) was approximately ten times greater than all other plants. Also, Brazilian pepper lived under conditions of significantly lower available phosphorus …

Environmental Influences On Bacterio-Phytoplanktonic Coupling And Bacterial Growth Efficiency In A Sub-Tropical Estuary, Rachel Kotkowski

FIU Electronic Theses and Dissertations

Bacterio-phytoplanktonic coupling and bacterial growth efficiency (BGE) measurements were used to analyze microbial trophic dynamics and the influence of environmental factors in Florida Bay, Florida. Phytoplankton gross primary productivity (GPP) was measured using 24-hour in situ oxygen incubations; bacterial productivity (BP) was measured using ³H- thymidine incorporation. Weak bacterio-phytoplanktonic coupling was observed over the sampling period. BP was more influenced by local total nitrogen concentrations while GPP was more evenly distributed. BGE rates were low but consistent with marine and estuarine ecosystems worldwide. Results suggest that bacterioplankton growth in Florida Bay is relatively uncoupled from phytoplankton production, which may …

Characterization Of Rhizobial Diversity And Relationship Of Rhizobial Partner And Legume Performance In Four South Florida Pine Rockland Soils, Vanessa Sánchez

FIU Electronic Theses and Dissertations

Pine rocklands are endangered ecosystems unique to south Florida, the Bahamas and Cuba. As a result of their karstic calcium carbonate­rich soil, these systems are limited in phosphorus and nitrogen, making symbiotic associations critical to plant growth. Four leguminous species (Cajanus cajan, Chamaecrista fasciculata, Tephrosia angustissima, and Abrus precatorious) were used to determine the relationship between rhizobial partners and plant performance, and the symbiosis related gene nifH was amplified to characterize the diversity of rhizobial symbionts. Plants were grown in soils from four different south Florida pine rocklands, and a salinity treatment was added to determine …

The Roles Of Microcystin And Sulfide In Physiology And Tactic Responses Of Pathogenic And Non-Pathogenic Mat-Forming Cyanobacteria, Abigael C. Brownell

FIU Electronic Theses and Dissertations

Planktothricoides raciborskii and Roseofilum reptotaenium are physiologically similar, yet ecologically distinct organisms found in a hot spring outflow and coral black band disease (BBD), respectively. The aim of this study was to elucidate the relationship between R. reptotaenium and sulfide in BBD, to compare microcystin (MC) production in response to environmental factors, and to determine chemotactic responses to MC and sulfide by the two organisms. Results showed that the pathogenicity of R. reptotaenium in BBD is dependent on sulfate-reducing bacteria as secondary pathogens. Roseofilum reptotaenium produced significantly more MC than P. raciborskii, as measured using ELISA. Roseofilum reptotaenium …

Real-Time Qpcr Assay Development For Detection Of Bacillus Thuringiensis And Serratia Marcescens Dna And The Influence Of Complex Microbial Community Dna On Assay Sensitivity, Jonathan Segal

FIU Electronic Theses and Dissertations

Real-time quantitative polymerase chain reaction (real-time qPCR) assays are an effective technique to detect biological warfare agents and surrogate organisms. In my study, primers were designed to detect chromosomal DNA of biological warfare agent surrogates B. thuringiensis and S. marcescens (representing B. anthracis and Y. pestis, respectively) via real-time qPCR. Species-level specificity of the primers was demonstrated through comparisons with a bacterial strain panel and corroborated by qPCR data. Additionally, the primer efficacy was tested when template DNA was spiked into metagenomic DNA extracted from clinical lung microbiome samples. The results showed that while detection of B. thuringiensis or …

Regulation Of Rab5 Gtpase Activity During Pseudomonas Aeruginosa-Macrophage Interaction, Sushmita Mustafi

FIU Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen. Several antibiotic resistant strains of P. aeruginosa are commonly found as secondary infection in immune-compromised patients leaving significant mortality and healthcare cost. Pseudomonas aeruginosa successfully avoids the process of phagocytosis, the first line of host defense, by secreting several toxic effectors. Effectors produced from P. aeruginosa Type III secretion system are critical molecules required to disrupt mammalian cell signaling and holds particular interest to the scientists studying host-pathogen interaction. Exoenzyme S (ExoS) is a bi-functional Type III effector that ADP-ribosylates several intracellular Ras (Rat sarcoma) and Rab (Response to abscisic acid) small GTPases …

Acclimatization Of The Tropical Reef Coral Acropora Millepora To Hyperthermal Stress, Anthony John Bellantuono

FIU Electronic Theses and Dissertations

The demise of reef-building corals potentially lies on the horizon, given ongoing climate change amid other anthropogenic environmental stressors. If corals cannot acclimatize or adapt to changing conditions, dramatic declines in the extent and health of the living reefs are expected within the next half century. The primary and proximal global threat to corals is climate change. Reef-building corals are dependent upon a nutritional symbiosis with photosynthetic dinoflagellates belonging to the group Symbiodinium. The symbiosis between the cnidarian host and algal partner is a stress-sensitive relationship; temperatures just 1°C above normal thermal maxima can result in the breakdown of …

Pseudomonas Aeruginosa Ampr Transcriptional Regulatory Network, Deepak Balasubramanian

FIU Electronic Theses and Dissertations

In Enterobacteriaceae, the transcriptional regulator AmpR, a member of the LysR family, regulates the expression of a chromosomal β-lactamase AmpC. The regulatory repertoire of AmpR is broader in Pseudomonas aeruginosa, an opportunistic pathogen responsible for numerous acute and chronic infections including cystic fibrosis. Previous studies showed that in addition to regulating ampC, P. aeruginosa AmpR regulates the sigma factor AlgT/U and production of some quorum sensing (QS)-regulated virulence factors. In order to better understand the ampR regulon, the transcriptional profiles generated using DNA microarrays and RNA-Seq of the prototypic P. aeruginosa PAO1 strain with its isogenic ampR deletion …

Identification Of Conserved Splicing Motifs In Mutually Exclusive Exons Of 15 Insect Species, Patricia Buendia, John Tyree, Robert Laredo, Shu-Ning Hsu

School of Computing and Information Sciences

Background: During alternative splicing, the inclusion of an exon in the final mRNA molecule is determined by nuclear proteins that bind cis-regulatory sequences in a target pre-mRNA molecule. A recent study suggested that the regulatory codes of individual RNA-binding proteins may be nearly immutable between very diverse species such as mammals and insects. The model system Drosophila melanogaster therefore presents an excellent opportunity for the study of alternative splicing due to the availability of quality EST annotations in FlyBase.

Methods: In this paper, we describe an in silico analysis pipeline to extract putative exonic splicing regulatory sequences from a multiple …