Bacteriology Commons^™

Antibacterial, Antifungal, Antioxidant Activity And Polyphenol Content Of Aerial Parts And Bulbs Of Allium Schugnanicum., Saidbeg Satorov, F. Mirzoeva, Sh. Kurbonbekova, Sh. Satorov, M. Vakhidova, Vyacheslav Dushenkov

Publications and Research

Objective: То study of antibacterial, antifungal and antioxidant activity, and content of polyphenols in the bulb and aerial parts of an endemic species of onion A. schugnanicum. Methods: An ethanol-based extract was prepared from fresh plants. Total polyphenolic content (Folin) and ABTS antioxidant capacity assays were used to characterized extracts. Extracts obtained from bulbs, peduncle, and seeds demonstrated antibacterial activity against the reference Staphylococcus aureus (ATCC 4929), Pseudomonas aeruginosa (ATCC 4930) and Klebsiella pneumoniae (ATCC 4927) strains, as well as against the hospital strains of the same types of bacteria, i.e. strains isolated from inpatient surgical patients. Results: The study …

High-Throughput Two-Stage Dereplication Of Cave Bacteria To Discover Novel Antibiotic Compounds, Alexander Archey

Williams Honors College, Honors Research Projects

Since their discovery over a century ago, antibiotics have been a staple of combating infectious diseases. However, bacteria develop resistance to antibiotics through a variety of mechanisms. Efforts to identify new antibiotics often fail by discovering already-known antibiotics, or failing to synthesize new antibiotics that are safe for clinical use. The aim of this research was to dereplicate bacteria- to screen for antibiotic production in- normally isolated in cave ecosystems. Using two new technologies, the Antibiotic Resistance Platform (ARP) and a data acquisition and bioinformatics technique (IDBac), my dereplicating method allowed high throughput of bacterial screening for antibiotics. In this …

The Effects Of Staining Cyanobacteria With Sytoxgreen After Lysis By Freeze-Thaw And Lysis By Ethanol, Samantha Galambos

Williams Honors College, Honors Research Projects

The purpose of this project is to find the effects of staining toxic cyanobacteria with SYTOXGreen after lysis by freeze-thaw and lysis by ethanol. This project will focus on two strains of toxic cyanobacteria known as Aphanizomenon - A. flos-aquae and Planktothrix - P. agardhii. The live and dead cells are observed under blue and red fluorescent light to show the effectiveness of each lysis. It is important that this topic is researched because it is significantly affecting our waterways and sometimes drinking water. We often see that you cannot swim in Lake Erie due to algae, more specifically, these …

Mucosa-Associated Microbiota In Barrett’S Esophagus, Dysplasia, And Esophageal Adenocarcinoma Differ Similarly Compared With Healthy Controls, Shajan Peter, Amanda Pendergraft,, William Vanderpol, Mel Wilcox, Kondal R. Kyanam Kabir Baig, Casey Morrow, Jacques Izard, Peter J. Mannon

Department of Food Science and Technology: Faculty Publications

Introduction: Alterations in the composition of the human gut microbiome and its metabolites have been linked to gut epithelial neoplasia. We hypothesized that differences in mucosa-adherent Barrett’s microbiota could link to risk factors, providing risk of progression to neoplasia.

Methods: Paired biopsies from both diseased and nonaffected esophagus (as well as gastric cardia and gastric juice for comparison) from patients with intestinal metaplasia (n = 10), low grade dysplasia (n = 10), high grade dysplasia (n = 10), esophageal adenocarcinoma (n = 12), and controls (n = 10) were processed for mucosa-associated bacteria …

The Role Of Manganese In Streptococcus Sanguinis, Tanya M. Puccio

Theses and Dissertations

Streptococcus sanguinis is primarily associated with oral health as a commensal bacterium. As an opportunistic pathogen, S. sanguinis is capable of colonizing heart valve vegetations, leading to the disease infective endocarditis. Previous studies from our lab have identified the high-affinity manganese transporter SsaACB as important for endocarditis virulence. The impact that manganese depletion has on S. sanguinis had never been evaluated and a secondary manganese transporter has not been identified. Thus, we employed the use of a fermentor to control large-scale growth over time and depleted manganese in an ΔssaACB mutant using a metal chelator, EDTA. The changes in …

Genomic And Taxonomic Studies Of An Antarctic Psychrotolerant Quorum Quenching Bacterium, Planococcus Versutus L10.15t, See-Too Wah Seng

Student Works (2020-2029)

Quorum quenching (QQ) has been suggested as an alternative to antibiotic treatments for pathogenic infections as it does not affect the viability of the pathogen and imposes minimum selection pressure promoting drug resistance. During an ecological survey for quorum quenching (QQ) bacteria from soil collected in Lagoon Island (Ryder Bay, Adelaide Island, Antarctica), a bacterial strain was isolated and identified as Planococcus species, L10.15T, based on 16S rRNA gene analysis. The genomic, phylogenetic, chemotaxonomic and phenotypic data obtained showed that L10.15T represents a novel species for which the name Planococcus versutus sp. nov. is proposed. Previously, QQ activity of L10.15T …

Genetic And Biochemical Analysis Of A Conserved, Multi-Gene System Regulation Spore-Associated Proteins In Streptomyces Coelicolor, Joseph Sallmen

Electronic Theses and Dissertations

Streptomyces coelicolor is a Gram positive, filamentous soil dwelling bacterium that exhibits a complex life cycle including the transition from a vegetative mycelium to a sporulating, aerial mycelium. Early genetic studies identified two classes of genes that resulted in developmental blocks, bald and white. The bald (bld) phenotype occurs when colonies cannot produce aerial hyphae. White (whi) colonies exhibit incomplete sporulation and/or loss of production of the concurrently produced grey pigment. While some of the original mutants have been explored, the developmental functions of many of the identified genes are not well understood. Of particular interest …

Genetic Analysis Of A Novel Ftsk Homolog, Hfka, In Streptomyces Coelicolor Development-Associated Chromosome Segregation, Sumedha Sethi

Electronic Theses and Dissertations

A quintessential phenomenon occurring during prokaryotic development is accurate segregation of the replicated genomes into the daughter cells. Key energy-dependent processes like chromosome condensation and subcellular partitioning of the genomes are driven by conserved proteins like SMC, ParB, FtsK. During its complex developmental cycle, Streptomyces coelicolor segregates its genomes into chains of unicellular spores when its multigenomic syncytial aerial hyphae undergo division.

A novel ftsK-like gene, hfkA (Homolog of FtsK protein A), was examined for function and localization during development-associated chromosome segregation. Individual deletions did not affect segregation, but a ΔhfkA ΔftsK mutant exhibited 8% anucleate …

Acid Resistance Mechanisms In Staphylococcus Aureus, Chunyi Zhou

Theses & Dissertations

Staphylococcus aureus is a leading cause of opportunistic infections in community and health care settings. To thrive in a great variety of environments, S. aureus has developed the capability of tolerating temporary pH changes, as well as resisting constant acid stress. To evaluate the impact of strong and weak acid stress on S. aureus, growth patterns of JE2 were monitored when cultured in chemically defined media (CDM) at various pH in the presence of hydrochloric acid (HCl), acetic acid, and lactic acid. Our results showed that S. aureus responds to strong and weak acids in different manners. S. aureus …

The Antimicrobial Activity And Cellular Targets Of Plant Derived Aldehydes And Degradable Pro-Antimicrobial Networks In Pseudomonas Aeruginosa, Yetunde Adewunmi

Dissertations

Essential oils (EOs) are plant-derived products that have been long exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to the broad-range antimicrobial activity, low toxicity to human commensal bacteria, and the capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the biological activity of EOs, many aspects of their mode of action remain inconclusive. The overarching aim of this work was to address these gaps by studying molecular interactions between antimicrobial plant aldehydes and the opportunistic human pathogen Pseudomonas aeruginosa. We initiated …

Growth Phase Proteomics Of The Heterotrophic Marine Bacterium Ruegeria Pomeroyi, Dasha Krayushkina, Emma Timmins-Schiffman, Jessica Faux, Damon H. May, Michael Riffle, H. Rodger Harvey, Brook L. Nunn

OES Faculty Publications

The heterotrophic marine bacterium, Ruegeria pomeroyi, was experimentally cultured under environmentally realistic carbon conditions and with a tracer-level addition of ¹³C-labeled leucine to track bacterial protein biosynthesis through growth phases. A combination of methods allowed observation of real-time bacterial protein production to understand metabolic priorities through the different growth phases. Over 2000 proteins were identified in each experimental culture from exponential and stationary growth phases. Within two hours of the ¹³C-labeled leucine addition, R. pomeroyi significantly assimilated the newly encountered substrate into new proteins. This dataset provides a fundamental baseline for understanding growth phase differences in molecular …

Species Richness And Ecological Diversity Of Myxomycetes And Myxomycete-Like Organisms In The Tropical Forests Of Brazil, Isadora Lima Coelho

Graduate Theses and Dissertations

Tropical rain forests cover less than two percent of Earth's surface, yet they sustain the greatest diversity of living organisms on the planet. Tropical rain forests cover nearly 73% of the Brazilian territory and besides harboring some of the most biodiverse ecosystems on the planet, this vast area also houses about 83% of the Brazilian population. Approximately 175 million people live in urban and rural areas with fragments of coverage of these biomes which contributes to the loss of biodiversity that rapidly increases over the years. Furthermore, the majority of the taxonomic and ecological efforts to describe and protect the …

The Role Of Multidrug Resistance Regulators Mara, Soxs, Rob And Rama In Regulating Virulence Traits In Salmonella Enterica, Srinivas Thota

Dissertations

Enteric pathogens sense numerous signals specific to the anatomical location in the intestine and integrate them with the complex regulatory networks to temporally and spatially regulate their virulence genes. MarA, SoxS, Rob and RamA are homologous transcription factors that belong to AraC family of proteins in Salmonella enterica that primarily were thought to be involved in rendering antibiotic resistance to bacteria by up regulating efflux pumps and down regulating outer membrane porins. The fact that these transcription factors respond to the same intestinal compounds that regulate virulence genes in Salmonella motivated us to look for other roles of these transcription …

Mechanism Of Neutrophil Homeostasis And Immunity In Pneumonia And Sepsis, Sagar Paudel

LSU Doctoral Dissertations

Severe bacterial pneumonia and septicemia are pressing health problems. A better understanding of cellular and molecular players of neutrophil immunity and homeostasis in bacterial pneumonia and sepsis is critical for inspiring novel therapeutics. Chemokine CXCL1 is a widely secreted neutrophil attractant and Nod-like receptor (NLRC4) is commonly expressed cytoplasmic pathogen sensor in hematopoietic compartments. How these innate mediators convert pathogen signals into molecular cues of immune response in context of Gram-positive bacterial pneumonia and septicemia largely remain unknown. Utilizing Cxcl1 gene deficient mice, we demonstrate CXCL1 regulates neutrophil influx, bacterial clearance, and host survival in pneumococcal pneumonia-derived sepsis. Furthermore, Cxcl1 …

Simulating Bacterial Growth, Competition, And Resistance With Agent-Based Models And Laboratory Experiments, Anne E. Yust, Davida S. Smyth

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Characterization Of Early Biofilm Formation And Physiology In Neisseria Gonorrhoeae, Kelly Eckenrode

Dissertations, Theses, and Capstone Projects

Many bacteria rely on the dynamics of their extracellular appendages to perform important tasks, like motility and biofilm formation. Interestingly, these dynamics have been linked to physiological responses in some pathogenic bacteria; therefore, it is important to understand more about the role of physical forces in bacteria. I used the causative agent of the human disease gonorrhea, Neisseria gonorrhoeae, as a model system to study the role of physical force on early biofilm formation. The advantage of this system is that cell-cell interactions are controlled by extracellular filaments called type IV pili (tfp). Tfp is composed of monomers that give …

Transposon Mutagenesis Facilitates Discovery Of Genotype-Phenotype Associations And Functional Interrogation Of The Mycobacterium Kansasii Genome, William C. Budell

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is a nontuberculous mycobacterium (NTM) and medically relevant opportunistic human pathogen. Mk causes dangerous disease pathologies ranging from tuberculosis-like chronic pulmonary disease (CPD) to non-pulmonary focal or disseminated infections that are exacerbated by comorbidities such as chronic obstructive pulmonary disease (COPD), co-infection with HIV, or cancer. Among the most frequently identified cause of NTM-linked CPD, Mk infections contribute to a globally increasing NTM disease burden and are difficult to treat, requiring a long-term, multi-drug regimen. Although a less virulent pathogen than Mycobacterium tuberculosis (Mtb), Mk elicits similar disease features and shares in vitro …

Characterization Of The Role Of Transcriptional Regulator Of Arac/Xyls Family In Tularemia Pathogenesis, Dina Marghani

NYMC Student Theses and Dissertations

The Tier 1 Select Agent, Francisella tularensis causes an acute and fatal disease known as tularemia. Many studies have devoted enormous efforts to understand how F. tularensis avoids host defense mechanisms, replicates within an extremely secure immune system, and eventually causes the deadly disease tularemia. The extremely high virulence of Francisella depends on its ability to manipulate gene expression according to the surrounding environment. This process requires the involvement of unique transcriptional regulators. Francisella possesses very few transcriptional regulators, and a majority of them characterized to-date have been shown to regulate genes involved in virulence and cellular functions. The role …

The Evolutionary Diversity And Biological Function Of Phenazine Metabolite Biosynthesis In Burkholderia Spp, Samuel Hendry

Master's Theses

Burkholderia encompass a group of ubiquitous Gram-negative bacteria that include numerous saprophytes, as well as several species that cause infections in animals, immunocompromised patients, and plants. Some species of Burkholderia produce colored redox-active secondary metabolites called phenazines (Phz). In the model opportunistic pathogen Pseudomonas aeruginosa, phenazines strongly contribute to the competitiveness, formation of biofilms, and virulence in multiple models of infection. Similar depth of knowledge on the diversity, biosynthesis, and biological functions of phenazines in Burkholderiais missing. This project aimed to bridge this gap in knowledge by focusing on phenazine pathways of B. lata and closely related …

The Influence Of The Pep-Pts And Other Metabolic Systems On The Master Virulence Regulator Atxa And To Xin Gene Expression In Bacillus Anthracis, Naomi Bier-Reizes

Dissertations and Theses (Open Access)

AtxA, the master virulence gene regulator in Bacillus anthracis, is a PRD-containing virulence regulator (PCVR) as indicated by the crystal structure, post-translational modifications, and activity of the protein. PCVRs are transcriptional regulators, named for the regulatory domains subject to phosphorylation by the phosphoenolpyruvate phosphotransferase system (PEP-PTS), termed PTS Regulatory Domains (PRD), and for their impact on virulence gene expression. Generally, the phosphorylation of a PCVR regulates protein activity and multimerization. AtxA is phosphorylated at two histidine residues - one in each of its two PRDs. Phosphorylation at position 199 allows for AtxA to positively affect expression of virulence genes, whereas …