Microbiology Commons^™

Effect Of Two-Year Caloric Restriction On Bone Metabolism And Bone Mineral Density In Non-Obese Younger Adults: A Randomized Clinical Trial, Dt Villareal, L Fontana, Sk Das, Et Al.

Faculty, Staff and Students Publications

Although caloric restriction (CR) could delay biologic aging in humans, it is unclear if this would occur at the cost of significant bone loss. We evaluated the effect of prolonged CR on bone metabolism and bone mineral density (BMD) in healthy younger adults. Two-hundred eighteen non-obese (body mass index [BMI] 25.1?±?1.7?kg/m(2) ), younger (age 37.9?±?7.2 years) adults were randomly assigned to 25% CR (CR group, n?=?143) or ad libitum (AL group, n?=?75) for 2 years. Main outcomes were BMD and markers of bone turnover. Other outcomes included body composition, bone-active hormones, nutrient intake, and physical activity. Body weight (-7.5?±?0.4 versus …

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 …

Tillage And Fertilization Influences On Autotrophic Nitrifiers In Agricultural Soil, Shuang Liu

Theses and Dissertations--Plant and Soil Sciences

Nitrification is a biological oxidation of NH₃ to NO₂^- and then to NO₃^-. Understanding how the nitrifier community responds to agricultural management is essential because the community composition is complex and functional distinction of subgroups occurs. Better managing nitrifiers could benefit the environment by increasing nitrogen (N) fertilizer use efficiency, decreasing NO₃^- leaching, and reducing NO and N₂O emissions. This study examined how long-term N fertilization and tillage influenced nitrifier density, ratios, nitrification rates, and the community structure of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and nitrite-oxidizing bacteria (NOB). The …

Studies On Regulation Of Pqq-Dependent Phosphate Solubilization Among Rhizosphere Dwelling Bacteria, Ran An

Theses and Dissertations--Plant and Soil Sciences

Plant growth promotion can be enhanced by soil- and rhizosphere-dwelling bacteria by a several different methods. One method is by promoting nutrient acquisition from soil. Phosphorus is an essential nutrient that plants obtain from soil, but in many cases it is immobilized in forms that are not available for plant uptake. Bacteria can solubilize insoluble soil phosphates by secreting gluconic acid. This chemical is produced from glucose by the activity of the bacterial enzyme glucose dehydrogenase, which requires a coenzyme called PQQ. In this dissertation, I studied the regulation of the glucose dehydrogenase enzyme and the PQQ coenzyme in the …

The Loss Of Methanol Utilization In Methylobacteria, Justin T. Skariah

Theses and Dissertations

Methylobacteria primary uses Cl substrates as a carbon and energy source. This experiment was performed to see if Methylobacteria would lose the ability to use Cl compound methanol after prolonged exposure to multi-carbon substrates. To determine this, the bacteria was grown on MR2A3 (multi-carbon substrates) and MOM (single-carbon substrates) for multiple generations and tested for loss of function on a series of generations. These tests include streaking plates of MOM and R2A with bacteria from MR2A3 then getting a bacterial colony count and also toothpick transfers of the colonies to verify findings. After 20 generations there were no significant decrease …

Diversity Of The Beneficial Bacterium Oxalobacter Formigenes Isolated From The Human Gut, Karen Shaw

Masters Theses

Oxalobacter formigenes is an anaerobic, oxalate degrading organism that colonizes in the mammalian intestinal tract. Currently, O. formigenes is divided into two groups via PCR of the oxc gene. Pulsed field gel electrophoresis (PFGE) is a technique used to resolve large pieces of DNA. Typically, PFGE is used to identify differences between strains for pathogenic bacteria, but this study sought to use it to further understand the diversity of a probiotic organism. This study aimed to develop a methodology for utilizing PFGE to examine O. formigenes. The methodology involved lysing O. formigenes cells in plugs, first in proteinase K, …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …

Response Of Soil Microbial Communities To Saltwater Intrusion In Tidal Freshwater Wetlands, Chansotheary Dang

Theses and Dissertations

Saltwater intrusion due to global change is expected to have a detrimental effect on the biogeochemistry of tidal freshwater wetlands. Of particular concern is that fact that salinization can alter the role of these ecosystems in the global carbon cycling by causing shifts in microbial metabolism that alter greenhouse gas emissions and increase carbon mineralization rates. However, our understanding of how wetland microbial community dynamics will respond to saltwater intrusion is limited. To address this knowledge gap and increase our understanding of how microbial communities in tidal freshwater wetlands change over time (1, 3, 12, and 49 weeks) under elevated …

Adenovirus Evasion Of Cell-Intrinsic Immunity, Andrew Michael Burrage

Dissertations

Virus cell entry represents one of the earliest opportunities for a host to respond to infection. Understanding the processes of pathogen detection and restriction employed by the host, as well as strategies utilized by the virus itself to evade such processes, is critical in developing therapeutics to counter pathogenesis. Adenovirus (Ad) infections are self-limiting in healthy populations, but can be devastating to individuals with compromised immune systems. Currently, no specific antiviral treatments exist to combat Ad infections in susceptible populations. However, because Ad infections are not severe in healthy individuals, employing replication-defective Ads as vaccine vectors is generally regarded as …

Draft Genome For A Urinary Isolate Of Lactobacillus Crispatus, Travis Kyle Price, Majed Shaheen, Laurynas Kalesinskas, Kema Malki, Evann Elizabeth Hilt, Catherine Putonti, Alan J. Wolfe

Bioinformatics Faculty Publications

While Lactobacillus crispatus contributes to the stability of normal vaginal microbiota, its role in urinary health remains unclear. As part of an on-going attempt to characterize the female urinary microbiota, we report the genome sequence of an L. crispatus strain isolated from a woman displaying no lower urinary tract symptoms.

Land-Use And Algal Species Influence Bacterial Community Composition And Activity In Streams, Miguel Rojas

Master's Theses

Microbial biofilms can be found on virtually all submerged surfaces in aquatic habitats, including rivers and streams. Biofilms are complex, taxonomically diverse communities of microorganisms (including algae and bacteria) that colonize solid surfaces and support a wide range of metabolic activities. Biofilms are critical components of river and stream ecosystems because they are key drivers of nutrient cycling processes (including nitrogen cycling) and because they serve as an important food source for higher trophic levels. Biofilms in urban streams are subject to a number of anthropogenic stressors, but research on the ecology of urban biofilms and their response to stressors …

Controlling Microbial Safety Challenges Of Meat Using High Voltage Atmospheric Cold Plasma, Lu Han, Dana Ziuzina, Caitlin Marie Heslin, Daniela Boehm, Apurva Patange, David Millan-Sango, Vasilis Valdramidis, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a non-thermal technology, effective against a wide range of pathogenic microorganisms. Inactivation efficacy results from plasma generated reactive species. These may interact with any organic components in a test matrix including the target microorganism, thus food components may exert a protective effect against the antimicrobial mode of action. The effect of an in-package high voltage ACP process applied in conjunction with common meat processing MAP gas compositions as well as bacteria type and meat model media composition have been investigated to determine the applicability of this technology for decontamination of safety challenges associated with meat …

Lactobacillus Crispatus Produces A Bacteridical Molecule That Kills Uropathogenic E. Coli, Katherine Diebel

Master's Theses

As many as 1 in 2 women will have at least one urinary tract infection (UTI) in their lifetime. UTIs can cause complications in pregnancy and decrease quality of life, and their treatment and prevention are expensive. Uropathogenic E. coli (UPEC) is the primary cause of UTI. The probiotic and bactericidal capacities of gut and vaginal Lactobacillus isolates have been studied, but the same attention has not been paid to urinary strains. These urinary isolates of L. crispatus appear to have a greater killing capacity against UPEC and this bactericidal activity does not depend on the cells themselves, consistent with …

Investigating The Regulatory Mechanisms By Which Arabinose And Sypa Control Biofilm Formation In Vibrio Fischeri, Sheila Paris

Master's Theses

Biofilms are surface-associated microbial communities surrounded by an extracellular matrix. Through biofilm formation, many pathogens and symbionts are able to colonize, survive, and persist in their host. A model system used to study biofilm formation is the symbiotic bacterium Vibrio fischeri, which colonizes its host, the squid Euprymna scolopes. Complex signaling between the squid and the bacteria is essential for the proper regulation of biofilm formation as well as for persistent colonization.

The signal(s) that promote host-relevant biofilm formation are as-yet unknown, but recently it was discovered that the sugar, L-arabinose, serves as a unique signal to promote biofilm formation …

Local Corticotropin Releasing Hormone (Crh) Signals To Its Receptor Crhr1 During Postnatal Development Of The Mouse Olfactory Bulb, Isabella Garcia, Paramjit K Bhullar, Burak Tepe, Joshua Ortiz-Guzman, Longwen Huang, Alexander M Herman, Lesley Chaboub, Benjamin Deneen, Nicholas J Justice, Benjamin R Arenkiel

Faculty, Staff and Students Publications

Neuropeptides play important physiological functions during distinct behaviors such as arousal, learning, memory, and reproduction. However, the role of local, extrahypothalamic neuropeptide signaling in shaping synapse formation and neuronal plasticity in the brain is not well understood. Here, we characterize the spatiotemporal expression profile of the neuropeptide corticotropin-releasing hormone (CRH) and its receptor CRHR1 in the mouse OB throughout development. We found that CRH-expressing interneurons are present in the external plexiform layer, that its cognate receptor is expressed by granule cells, and show that both CRH and CRHR1 expression enriches in the postnatal period when olfaction becomes important towards olfactory-related …

Clinical Coagulase-Negative Staphylococci; Identification, Characterisation And Treatment, Emma Gabriel

Theses

The work presented in this thesis focuses on clinically significant staphylococci (with an emphasis on coagulase-negative staphylococci) in terms of their isolation, identification, characterisation, and biocontrol.

CoNS are increasingly being recognised as true nosocomial pathogens yet remain under-characterised, particularly from an Irish clinical perspective. We examined a large cohort of clinically-derived CoNS, isolated from blood (n=l35), identifying them to species level. Extensive antibiotic resistance against nine clinically-relevant antibiotics was recorded. Additionally, widespread biofilm forming capabilities associated with increased virulence was detected both phenotypically and genotypically. We identified multiple species of CoNS in circulation in an Irish healthcare setting, and determined …

Determination Of Cyclic-Di-Gmp- Controlled Gene Expression In A Pharmacologically Important Bacterium, Morgan A. Stark

Undergraduate Honors Thesis Projects

The second messenger molecule cyclic dimeric GMP (c-di-GMP) regulates a myriad of processes in gram-negative bacteria. However, less is known about the roles it plays in gram-positive bacteria. Differential gene expression in three strains of the gram-positive bacterium, Streptomyces coelicolor, is being studied using RNA sequencing and Real Time PCR to gain insight into c-di-GMP signaling. The rmdA rmdB (regulator of morphology and development) double mutant was compared to the wild type strain known as MT1110. The rmdA and rmdB genes are needed for the formation of aerial mycelium, an important step in the life cycle of Streptomyces coelicolor (Hull …

Interactomics-Based Functional Analysis: Using Interaction Conservation To Probe Bacterial Protein Functions, J. Harry Caufield

Theses and Dissertations

The emergence of genomics as a discrete field of biology has changed humanity’s understanding of our relationship with bacteria. Sequencing the genome of each newly-discovered bacterial species can reveal novel gene sequences, though the genome may contain genes coding for hundreds or thousands of proteins of unknown function (PUFs). In some cases, these coding sequences appear to be conserved across nearly all bacteria. Exploring the functional roles of these cases ideally requires an integrative, cross-species approach involving not only gene sequences but knowledge of interactions among their products. Protein interactions, studied at genome scale, extend genomics into the field of …

Sulfate-Reducing Bacteria Community Analysis: Isco/Isb Coupled Remediation, Christopher K. Bartlett

Theses and Dissertations (Comprehensive)

Improved techniques for remediating groundwater systems are required for the more than 500,000 contaminated sites in North America. Many of these sites are the legacy of historical industrial operations, inappropriate disposal practices and accidental releases. The most widely observed contaminant at many of these sites is petroleum hydrocarbons (PHCs). Recently, remediation efforts that involve the sequential application of treatment technologies have gained widespread interest. One specific sequential technology application or treatment train employs the aggressive nature of a chemical oxidation followed by bioremediation for polishing. When persulfate is used as the chemical oxidant its natural degradation by-product is sulfate, an …

Atmospheric Cold Plasma Interactions With Modified Atmosphere Packaging Inducer Gases For Safe Food Preservation., Lu Han, Daniela Boehm, Vladimir Milosavljević, Ester Amias, Patrick J. Cullen, Paula Bourke

Articles

Diverse microbiological challenges and pervasive microbial resistance drive technological development in food processing, where increasing process complexity and consumer demand for less processed goods leads to strong demand for effective decontamination. Atmospheric cold plasma (ACP) has wide potential for decontamination application in the food sector. We investigated the effect of Modified Atmosphere Packaging (MAP) gas mixtures on reactive species generated, their efficacy and mechanism of inactivation against Escherichia coli, Listeria monocytogenes and Staphylococcus aureus. Oxygen levels in the applied working gas had positive interactive effects on ROS generation, in-package inactivation efficacy in conjunction with post-treatment storage time. …