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Articles 91 - 120 of 229

Full-Text Articles in Microbiology

The Otud5–Ubr5 Complex Regulates Fact-Mediated Transcription At Damaged Chromatin, Angelo De Vivo, University Of South Florida, Jose Yegres, Jeonghyeon Kim, Sylvia Emly, Younghoon Kee Jan 2019

The Otud5–Ubr5 Complex Regulates Fact-Mediated Transcription At Damaged Chromatin, Angelo De Vivo, University Of South Florida, Jose Yegres, Jeonghyeon Kim, Sylvia Emly, Younghoon Kee

Molecular Biosciences Faculty Publications

Timely stalling and resumption of RNA polymerases at damaged chromatin are actively regulated processes. Prior work showed an importance of FACT histone chaperone in such process. Here we provide a new role of OTUD5 deubiquitinase in the FACT-dependent process. Through a DUB RNAi screen, we found OTUD5 as a specific stabilizer of the UBR5 E3 ligase. OTUD5 localizes to DNA double strand breaks (DSBs), interacts with UBR5 and represses the RNA Pol II elongation and RNA synthesis. OTUD5 co-localizes and interacts with the FACT component SPT16 and antagonizes the histone H2A deposition at DSB lesions. OTUD5 interacts with UBR5 and …


Evaluating Human-Associated Escherichia Coli Marker Genes For Microbial Source Tracking Applications In Florida, Jacob K. Senkbeil Nov 2018

Evaluating Human-Associated Escherichia Coli Marker Genes For Microbial Source Tracking Applications In Florida, Jacob K. Senkbeil

USF Tampa Graduate Theses and Dissertations

Fecal pollution of surface water can lead to human health issues because waterborne transmission of pathogens is a common cause of gastroenteritis. Genetic markers developed for human-associated Escherichia coli (H8, H12, H14, and H24) are promising tools for microbial source tracking (MST) of sewage in environmental waterbodies but are untested in the US. H gene marker performance characteristics (specificity, sensitivity, and prevalence) were assessed, with the goal of developing a quantitative PCR assay for the markers with the best performance. Individual E. coli isolates from reference samples were tested to determine end-point PCR assay performance. Three hundred E. coli strains …


Uncoupling The Folding And Binding Of An Intrinsically Disordered Protein, Anusha Poosapati, Emily Gregory, Wade M. Borcherds, Lucia B. Chemes, Gary Daughdrill Aug 2018

Uncoupling The Folding And Binding Of An Intrinsically Disordered Protein, Anusha Poosapati, Emily Gregory, Wade M. Borcherds, Lucia B. Chemes, Gary Daughdrill

Molecular Biosciences Faculty Publications

The relationship between helical stability and binding affinity was examined for the intrinsically disordered transactivation domain of the myeloblastosis oncoprotein, c-Myb, and its ordered binding partner, KIX. A series of c-Myb mutants was designed to either increase or decrease helical stability without changing the binding interface with KIX. This included a complimentary series of A, G, P, and V mutants at three non-interacting sites. We were able to use the glycine mutants as a reference state and show a strong correlation between binding affinity and helical stability. The intrinsic helicity of c-Myb is 21%, and helicity values of the …


Anemarrhena Asphodeloides Bunge And Its Constituent Timosaponin‐Aiii Induce Cell Cycle Arrest And Apoptosis In Pancreatic Cancer Cells, Catherine B. Marelia, Arielle Sharp, Tiffany A. Shemwell, Y. C. Zhang, Brant R. Burkhardt Jul 2018

Anemarrhena Asphodeloides Bunge And Its Constituent Timosaponin‐Aiii Induce Cell Cycle Arrest And Apoptosis In Pancreatic Cancer Cells, Catherine B. Marelia, Arielle Sharp, Tiffany A. Shemwell, Y. C. Zhang, Brant R. Burkhardt

Molecular Biosciences Faculty Publications

Pancreatic cancer is one of the most recalcitrant and lethal of all cancers. We examined the effects of Anemarrhena asphodeloides (AA) and timosaponin‐AIII (TAIII), a steroidal saponin present in AA, on pancreatic cancer cell proliferation and aimed to elucidate their potential apoptotic mechanisms of action. Viability assays and cell cycle analysis revealed that both AA and TAIII significantly inhibited pancreatic cancer cell proliferation and cell cycle progression compared to treatment with gemcitabine, the standard chemotherapeutic agent for advanced pancreatic cancer. We identified a dose‐dependent increase in caspase‐dependent apoptosis and activation of pro‐apoptotic PI3K/Akt pathway proteins, with a subsequent downregulation of …


Bacterial Diversity Associated With Mineral Substrates And Hot Springs From Caves And Tunnels Of The Naica Underground System (Chihuahua, Mexico), Adriana Espino Del Castillo, Hugo Beraldi-Campesi, Patricia Amador-Lemus, Hiram Isaac Beltrán, Sylvie Le Borgne Jun 2018

Bacterial Diversity Associated With Mineral Substrates And Hot Springs From Caves And Tunnels Of The Naica Underground System (Chihuahua, Mexico), Adriana Espino Del Castillo, Hugo Beraldi-Campesi, Patricia Amador-Lemus, Hiram Isaac Beltrán, Sylvie Le Borgne

International Journal of Speleology

The Naica Underground System (NUS) in Northern Mexico comprises a lead, zinc, and silver producing mine and displays the largest gypsum crystals ever found in natural caves. The caves are now closed to the public and mining activities have been suspended for an undefined period since October 2015. Besides its geological, economical, and tourist importance, the bacterial diversity in the NUS has not been fully explored yet. This study surveyed for bacteria present on different mineral substrates (gypsum crystals, iron oxide crusts) and hot spring samples collected before the NUS was inaccessible, using culture-dependent and culture–independent (PCR-DGGE) methods. This study …


Antimicrobial Activities Of Culturable Microorganisms (Actinomycetes And Fungi) Isolated From Chaabe Cave, Algeria, Larbi Belyagoubi, Nabila Belyagoubi-Benhammou, Valme Jurado, Joëlle Dupont, Sandrine Lacoste, Fatima Djebbah, Fatima Z. Ounadjela, Souad Benaissa, Salim Habi, Djamel E. Abdelouahid, Cesareo Saiz-Jimenez Jun 2018

Antimicrobial Activities Of Culturable Microorganisms (Actinomycetes And Fungi) Isolated From Chaabe Cave, Algeria, Larbi Belyagoubi, Nabila Belyagoubi-Benhammou, Valme Jurado, Joëlle Dupont, Sandrine Lacoste, Fatima Djebbah, Fatima Z. Ounadjela, Souad Benaissa, Salim Habi, Djamel E. Abdelouahid, Cesareo Saiz-Jimenez

International Journal of Speleology

The discovery of new antibiotics and other bioactive microbial metabolites is a priority given the frequency of the emerging multi-drug resistant pathogenic microorganisms. Thus, scientists are searching for new antibiotics in microorganisms isolated from extreme habitats such as caves. In the present study, we aimed to perform the first analysis on culturable microorganisms in the Chaabe Cave (Algeria), and to test the antimicrobial activities of the isolates (Streptomyces spp. and Penicillium spp.). The potential for antimicrobial activity of 47 strains of actinomycetes and 23 strains of fungi were tested on Candida albicans, Staphylococcus aureus, Micrococcus luteus, Listeria monocytogenes, …


Microbial Associations Of Four Species Of Algal Symbiont-Bearing Foraminifera From The Florida Reef Tract, Usa, Makenna May Martin Jun 2018

Microbial Associations Of Four Species Of Algal Symbiont-Bearing Foraminifera From The Florida Reef Tract, Usa, Makenna May Martin

USF Tampa Graduate Theses and Dissertations

Marine microbiome research is a rapidly expanding field of study, as scientists investigate the functions of microbial associations in eukaryotic organisms. Foraminifera are among the most abundant shelled organisms in the oceans, yet little is known of their associated microbiomes. This study investigated microbes associated with four species of Foraminifera that host three kinds of algal endosymbionts. The Order Miliolida, Family Soritidae, was represented by three species: Archaias angulatus and Cyclorbiculina compressa, which both host chlorophyte symbionts, and Sorites orbiculus, which hosts dinoflagellate symbionts. The fourth species, Amphistegina gibbosa, belongs to the Order Rotaliida and hosts diatom endosymbionts. Bacterial DNA …


Gesture: An Online Hand-Drawing Tool For Gene Expression Pattern Search, Chunyan Wang, Yiqing Xu, Xuelin Wang, Li Zhang, Suyun Wei, Qiaolin Ye, Youxiang Zhu, Hengfu Yin, Manoj Nainwal, Luis Tanon-Reyes, Feng Cheng, Tongming Yin, Ning Ye Jun 2018

Gesture: An Online Hand-Drawing Tool For Gene Expression Pattern Search, Chunyan Wang, Yiqing Xu, Xuelin Wang, Li Zhang, Suyun Wei, Qiaolin Ye, Youxiang Zhu, Hengfu Yin, Manoj Nainwal, Luis Tanon-Reyes, Feng Cheng, Tongming Yin, Ning Ye

Molecular Biosciences Faculty Publications

Gene expression profiling data provide useful information for the investigation of biological function and process. However, identifying a specific expression pattern from extensive time series gene expression data is not an easy task. Clustering, a popular method, is often used to classify similar expression genes, however, genes with a ‘desirable’ or ‘user-defined’ pattern cannot be efficiently detected by clustering methods. To address these limitations, we developed an online tool called GEsture. Users can draw, or graph a curve using a mouse instead of inputting abstract parameters of clustering methods. GEsture explores genes showing similar, opposite and time-delay expression patterns with …


Identification Of A Novel Polyamine Scaffold With Potent Efflux Pump Inhibition Activity Toward Multi-Drug Resistant Bacterial Pathogens, Renee Fleeman, Ginamarie Debevec, Kirsten Antonen, Jessie Adams, Radleigh G. Santos, Gregory S. Welmaker, Richard A. Houghten, Marc A. Guilianotti, Lindsey N. Shaw Jun 2018

Identification Of A Novel Polyamine Scaffold With Potent Efflux Pump Inhibition Activity Toward Multi-Drug Resistant Bacterial Pathogens, Renee Fleeman, Ginamarie Debevec, Kirsten Antonen, Jessie Adams, Radleigh G. Santos, Gregory S. Welmaker, Richard A. Houghten, Marc A. Guilianotti, Lindsey N. Shaw

Molecular Biosciences Faculty Publications

We have previously reported the use of combinatorial chemistry to identify broad-spectrum antibacterial agents. Herein, we extend our analysis of this technology toward the discovery of anti-resistance molecules, focusing on efflux pump inhibitors. Using high-throughput screening against multi-drug resistant Pseudomonas aeruginosa, we identified a polyamine scaffold that demonstrated strong efflux pump inhibition without possessing antibacterial effects. We determined that these molecules were most effective with an amine functionality at R1 and benzene functionalities at R2 and R3. From a library of 188 compounds, we studied the properties of 5 lead agents in detail, observing a fivefold to eightfold decrease …


Sulfur Cave (Romania), An Extreme Environment With Microbial Mats In A Co2-H2S/O2 Gas Chemocline Dominated By Mycobacteria, Serban M. Sarbu, Joost W. Aerts, Jean-François Flot, Rob J.M. Van Spanning, Calin Baciu, Artur Ionescu, Boglárka M. Kis, Reka Incze, Sándor Sikó-Barabási, Zoltan Para, Botond Hegyeli, Nicu-Viorel Atudorei, Casey Barr, Kenneth Nealson, Ferenc L. Forray, Cristian Lascu, Emily J. Fleming, Wilbert Bitter, Radu Popa May 2018

Sulfur Cave (Romania), An Extreme Environment With Microbial Mats In A Co2-H2S/O2 Gas Chemocline Dominated By Mycobacteria, Serban M. Sarbu, Joost W. Aerts, Jean-François Flot, Rob J.M. Van Spanning, Calin Baciu, Artur Ionescu, Boglárka M. Kis, Reka Incze, Sándor Sikó-Barabási, Zoltan Para, Botond Hegyeli, Nicu-Viorel Atudorei, Casey Barr, Kenneth Nealson, Ferenc L. Forray, Cristian Lascu, Emily J. Fleming, Wilbert Bitter, Radu Popa

International Journal of Speleology

Sulfur Cave (Puturosu Mountain, Romania) is an extreme environment, unique for displaying life in a gas chemocline. The lower part of the cave is filled with CO2, CH4, and H2S of mofettic origin, while the upper part contains air that floats above the heavier volcanic gasses. S° and H2SO4 (from sulfur-oxidation) cover the cave wall at and below the CO2-H2S:O2 gas/gas interface. On the cave wall, near the interface the pH is < 1 and unusual microbial biofilms occur on the rock’s surface. We provide context information on the geology, mineralogy, chemistry and biology to better understand this unique environment. We have used X-ray diffraction, optical microscopy, scanning electron microscopy with EDAX capabilities, stable isotope analysis and 16S and 18S rDNA amplicon sequencing. The most common taxa in the microbial biofilms are Mycobacteria, Acidithiobacillus and Ferroplasmaceae. Liquid water in this system originates solely from condensation of water …


Circulating Pander Concentration Is Associated With Increased Hba1c And Fasting Blood Glucose In Type 2 Diabetic Subjects, Catherine B. Marelia, Melanie N. Kuehl, Tiffany A. Shemwell, Amy C. Alman, Brant R. Burkhardt Mar 2018

Circulating Pander Concentration Is Associated With Increased Hba1c And Fasting Blood Glucose In Type 2 Diabetic Subjects, Catherine B. Marelia, Melanie N. Kuehl, Tiffany A. Shemwell, Amy C. Alman, Brant R. Burkhardt

Molecular Biosciences Faculty Publications

Aim: PANcreatic-DERived factor (PANDER, FAM3B) is a novel hormone that regulates glucose levels via interaction with both the endocrine pancreas and liver. Prior studies examining PANDER were primarily conducted in murine models or in vitro but little is known regarding the circulating concentration of PANDER in humans, especially with regard to the association of type 2 diabetes (T2D) or overall glycemic regulation. To address this limitation, we performed a cross-sectional analysis of circulating serum PANDER concentration in association with other hormones that serve as either markers of insulin resistance (insulin and adiponectin) or to metabolic parameters of glycemic control such …


Expression And Function Of Nuclear Receptor Coactivator 4 Isoforms In Transformed Endometriotic And Malignant Ovarian Cells, Stephanie Rockfield, Idhaliz Flores, Meera Nanjundan Jan 2018

Expression And Function Of Nuclear Receptor Coactivator 4 Isoforms In Transformed Endometriotic And Malignant Ovarian Cells, Stephanie Rockfield, Idhaliz Flores, Meera Nanjundan

Molecular Biosciences Faculty Publications

Iron is proposed to contribute to the transition from endometriosis to specific subtypes of ovarian cancers (OVCAs). Regulation of intracellular iron occurs via a ferritinophagic process involving NCOA4 (Nuclear Receptor Coactivator 4), represented by two major isoforms (NCOA4α and NCOA4β), whose contribution to ovarian cancer biology remains uninvestigated. We thus generated transformed endometriotic cells (via HRASV12A, c-MYCT58A, and p53 inactivation) whose migratory potential was increased in response to conditioned media from senescent endometriotic cells. We identified elevated NCOA4 mRNA in transformed endometriotic cells (relative to non-transformed). Knockdown of NCOA4 increased ferritin heavy chain (FTH1) and p21 …


Mbd2-Cp2c Loop Drives Adult-Type Globin Gene Expression And Definitive Erythropoiesis, Min Young Kim, Ji Sook Kim, Seung Han Son, Chang Su Lim, Hea Young Eum, Dae Hyun Ha, Mi Ae Park, Eun Jung Baek, Buom-Yong Ryu, Ho Chul Kang, Vladimir N. Uversky, Chul Geun Kim Jan 2018

Mbd2-Cp2c Loop Drives Adult-Type Globin Gene Expression And Definitive Erythropoiesis, Min Young Kim, Ji Sook Kim, Seung Han Son, Chang Su Lim, Hea Young Eum, Dae Hyun Ha, Mi Ae Park, Eun Jung Baek, Buom-Yong Ryu, Ho Chul Kang, Vladimir N. Uversky, Chul Geun Kim

Molecular Biosciences Faculty Publications

During hematopoiesis, red blood cells originate from the hematopoietic stem cell reservoir. Although the regulation of erythropoiesis and globin expression has been intensively investigated, the underlining mechanisms are not fully understood, including the interplay between transcription factors and epigenetic factors. Here, we uncover that the Mbd2-free NuRD chromatin remodeling complex potentiates erythroid differentiation of proerythroblasts via managing functions of the CP2c complexes. We found that both Mbd2 and Mbd3 expression is downregulated during differentiation of MEL cells in vitro and in normal erythropoiesis in mouse bone marrow, and Mbd2 downregulation is crucial for erythropoiesis. In uninduced MEL cells, the Mbd2-NuRD …


Yeast Lifespan Variation Correlates With Cell Growth And Sir2 Expression, Jessica T. Smith, Jill W. White, Huzefa Dungrawala, Hui Hua, Brandt L. Schneider Jan 2018

Yeast Lifespan Variation Correlates With Cell Growth And Sir2 Expression, Jessica T. Smith, Jill W. White, Huzefa Dungrawala, Hui Hua, Brandt L. Schneider

Molecular Biosciences Faculty Publications

Isogenic wild type yeast cells raised in controlled environments display a significant range of lifespan variation. Recent microfluidic studies suggest that differential growth or gene expression patterns may explain some of the heterogeneity of aging assays. Herein, we sought to complement this work by similarly examining a large set of replicative lifespan data from traditional plate assays. In so doing, we reproduced the finding that short-lived cells tend to arrest at senescence with a budded morphology. Further, we found that wild type cells born unusually small did not have an extended lifespan. However, large birth size and/or high inter-generational growth …


Radx Modulates Rad51 Activity To Control Replication Fork Protection, Kamakoti P. Bhat, Archana Krishnamoorthy, Huzefa Dungrawala, Edwige B. Garcin, Mauro Modesti, David Cortez Jan 2018

Radx Modulates Rad51 Activity To Control Replication Fork Protection, Kamakoti P. Bhat, Archana Krishnamoorthy, Huzefa Dungrawala, Edwige B. Garcin, Mauro Modesti, David Cortez

Molecular Biosciences Faculty Publications

RAD51 promotes homologous recombination repair (HR) of double-strand breaks and acts during DNA replication to facilitate fork reversal and protect nascent DNA strands from nuclease digestion. Several additional HR proteins regulate fork protection by promoting RAD51 filament formation. Here, we show that RADX modulates stalled fork protection by antagonizing RAD51. Consequently, silencing RADX restores fork protection in cells deficient for BRCA1, BRCA2, FANCA, FANCD2, or BOD1L. Inactivating RADX prevents both MRE11- and DNA2-dependent fork degradation. Furthermore, RADX overexpression causes fork degradation that is dependent on these nucleases and fork reversal. The amount of RAD51 determines the fate of stalled replication …


Septal Secretion Of Protein A In Staphylococcus Aureus Requires Seca And Lipoteichoic Acid Synthesis, Wenqi Yu, Dominique Missiakas, Olaf Schneewind Jan 2018

Septal Secretion Of Protein A In Staphylococcus Aureus Requires Seca And Lipoteichoic Acid Synthesis, Wenqi Yu, Dominique Missiakas, Olaf Schneewind

Molecular Biosciences Faculty Publications

Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and …


Evaluation Of A Microsphere-Based Immunoassay (Mia) In Measuring Diagnostic And Prognostic Markers Of Dengue Virus Infection, Jason H. Ambrose Nov 2017

Evaluation Of A Microsphere-Based Immunoassay (Mia) In Measuring Diagnostic And Prognostic Markers Of Dengue Virus Infection, Jason H. Ambrose

USF Tampa Graduate Theses and Dissertations

Infections with dengue viruses (DENV) constitute both a global problem as well as locally in Florida. DENV comprise four distinct serotypes of single-stranded RNA viruses and belong to the family Flaviviridae. DENV are among the most medically important arboviruses in the world and cases may currently exceed 400 million per annum. Additionally, dengue established its first recorded endemic transmission cycle in the state of Florida in over a half century, first within the Florida Keys during 2009-10 followed by an unrelated outbreak in Martin County in 2013. The clinical profile of DENV infections ranges from a mild febrile illness …


The Ecology Of Antibiotic Resistance: Sources And Persistence Of Vancomycin-Resistant Enterococci And Antibiotic Resistant Genes In Aquatic Environments, Suzanne M. Young Nov 2017

The Ecology Of Antibiotic Resistance: Sources And Persistence Of Vancomycin-Resistant Enterococci And Antibiotic Resistant Genes In Aquatic Environments, Suzanne M. Young

USF Tampa Graduate Theses and Dissertations

The growing crisis of antibiotic resistance is a major threat to ecosystems and human health. Infections caused by known and emerging antibiotic resistant pathogens are on the rise globally, with approximately 700,000 deaths per year caused by antibiotic resistant bacteria (1). In the United States, infections from antibiotic resistant bacteria cause more than 2 million illnesses and 23,000 deaths (2). Antibiotic resistant bacteria and antibiotic resistance genes are released into aquatic ecosystems through hospital waste, residential sewer lines and animal agricultural waste streams. Animal agriculture accounts for approximately 70% of antibiotic use in the United States (3). In agricultural ecosystems, …


Mechanism Elucidation And Inhibitor Discovery Against Serine And Metallo-Beta-Lactamases Involved In Bacterial Antibiotic Resistance, Orville A. Pemberton Nov 2017

Mechanism Elucidation And Inhibitor Discovery Against Serine And Metallo-Beta-Lactamases Involved In Bacterial Antibiotic Resistance, Orville A. Pemberton

USF Tampa Graduate Theses and Dissertations

The emergence and proliferation of Gram-negative bacteria expressing β-lactamases is a significant threat to human health. β-Lactamases are enzymes that degrade the β-lactam antibiotics (e.g., penicillins, cephalosporins, monobactams, and carbapenems) that we use to treat a diverse range of bacterial infections. Specifically, β-lactamases catalyze a hydrolysis reaction where the β-lactam ring common to all β-lactam antibiotics and responsible for their antibacterial activity, is opened, leaving an inactive drug. There are two groups of β-lactamases: serine enzymes that use an active site serine residue for β-lactam hydrolysis and metalloenzymes that use either one or two zinc ions for catalysis. Serine enzymes …


Packaging Of Genetic Material By Gene Transfer Agents (Gtas) Produced By Marine Roseobacter Species And Their Effect On Stimulating Bacterial Growth, Shahd Bader Aljandal Nov 2017

Packaging Of Genetic Material By Gene Transfer Agents (Gtas) Produced By Marine Roseobacter Species And Their Effect On Stimulating Bacterial Growth, Shahd Bader Aljandal

USF Tampa Graduate Theses and Dissertations

Horizontal gene transfer is one of the most important mechanisms for prokaryotic genome innovation and evolution. Gene Transfer Agents (GTAs) are phage-like particles that package small fragments of the genome of a GTA-producing bacterial cell. GTA chromosomal gene clusters usually contain 15-conserved open reading frames (ORFs) and are present in most of the sequenced marine alpha-proteobacteria genomes. Some marine strains have been shown to produce GTA particles that were biologically active in marine environment.

GTA particles range in size, morphology and the amount of host DNA they package. To date, the characteristics of GTAs are largely based on observations of …


Cell Division Regulation In Staphylococcus Aureus, Catherine M. Spanoudis Oct 2017

Cell Division Regulation In Staphylococcus Aureus, Catherine M. Spanoudis

USF Tampa Graduate Theses and Dissertations

Cell division is a fundamental biological process that occurs in all kingdoms of life. Our understanding of cell division in bacteria stems from studies in the rod-shaped model organisms: Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. The molecular underpinnings of cell division regulation in non-rod-shaped bacteria remain to be studied in detail. Rod-shaped bacteria possess many positive and negative regulatory proteins that are essential to the proper placement of the division septa and ultimately the production of two identical daughter cells, many of which are absent in cocci. Given that essential cell division proteins are attractive antibacterial drug targets, it …


Role Of Viruses Within Metaorganisms: Ciona Intestinalis As A Model System, Brittany A. Leigh Sep 2017

Role Of Viruses Within Metaorganisms: Ciona Intestinalis As A Model System, Brittany A. Leigh

USF Tampa Graduate Theses and Dissertations

Marine animals live and thrive in a literal sea of microorganisms, yet are often able to maintain specific associations that are largely dictated by the environment, host immunity and microbial interactions. Animal-associated microbiomes include bacteria and viruses that vastly outnumber host cells, especially in the gut environment, and are considered to be integral parts of healthy, functioning animals that act as a metaorganism. However, the processes underlying the initial establishment of these microbial communities are not very well understood. This dissertation focuses on the establishment of a well-known developmental animal model, Ciona intestinalis (sea squirt), to study the establishment and …


Screening Of Antifungal Susceptibility In Cave-Dwelling Aspergilli And Report Of An Amphotericin B-Resistant Aspergillus Flavus, Erika L.S. Taylor, Gabriella F. Ferreira, Gustavo J.C. Freitas, Rodrigo L. Ferreira, Daniel De Assis Santos, Maria A. De Resende-Stoianoff Aug 2017

Screening Of Antifungal Susceptibility In Cave-Dwelling Aspergilli And Report Of An Amphotericin B-Resistant Aspergillus Flavus, Erika L.S. Taylor, Gabriella F. Ferreira, Gustavo J.C. Freitas, Rodrigo L. Ferreira, Daniel De Assis Santos, Maria A. De Resende-Stoianoff

International Journal of Speleology

Caves are stable environments that favour the development of several microorganisms. The aspergilli represent a large number of species isolated from caves including strains capable of causing serious invasive opportunistic infections in humans. Considering that caves may harbour resistant strains to many antibiotics, investigation on the response of opportunistic aspergilli, isolated from pristine and tourist caves to antifungal agents and the mechanisms involved in resistance might be clinically relevant. A total of 32 strains of the species Aspergillus candidus, A. flavus, A. fumigatus, A. niger, A. tamarii, and A. terreus were isolated from caves in …


Discovering Antibacterial And Anti-Resistance Agents Targeting Multi-Drug Resistant Eskape Pathogens, Renee Fleeman Jul 2017

Discovering Antibacterial And Anti-Resistance Agents Targeting Multi-Drug Resistant Eskape Pathogens, Renee Fleeman

USF Tampa Graduate Theses and Dissertations

Antibiotic resistance has been a developing problem for mankind in recent decades and multi-drug resistant bacteria are now encountered that are resistant to all treatment options available. In 2014, the World Health Organization announced that this problem is driving us towards a “post-antibiotic era” that will change the face of modern medicine as we know it. If lack of novel antibiotic development and FDA approval continues, by the year 2050, 10 million people will die each year to an antimicrobial resistant bacterial infection. With lack of pharmaceutical industry involvement in developing novel antibiotics, the responsibility now lies within the academic …


Non-Classical Regulators In Staphylococcus Aureus, Andy Weiss Apr 2017

Non-Classical Regulators In Staphylococcus Aureus, Andy Weiss

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a highly problematic human pathogen due to its ability to cause devastating infections, paired with a capacity to withstand the action of a large fraction of available antibiotics. Both pathogenicity and antibiotic resistance are encoded by numerous genomic elements, though the expression of these factors is energetically costly and not always beneficial for cellular survival. Therefore, S. aureus has developed sophisticated regulatory networks to integrate a multitude of signals, enabling it to navigate the delicate balance between its pathogenic lifestyle and baseline needs for cellular energy homeostasis. It is thus imperative to study S. aureus behavior and …


A Novel Approach To The Discovery Of Natural Products From Actinobacteria, Rahmy Tawfik Mar 2017

A Novel Approach To The Discovery Of Natural Products From Actinobacteria, Rahmy Tawfik

USF Tampa Graduate Theses and Dissertations

Actinobacteria, primarily the genus Streptomyces, have led to the development of a number of antibiotics, which result from their secondary metabolites or modified derivatives. Secondary metabolite production can result from competition with neighboring microbes in an effort to disrupt growth, aiding in the competition for vital nutrients in impoverished conditions. Such secondary metabolites have the potential to affect a plethora of cellular functions in target cells, including, cell wall development, protein synthesis, protein function and fatty acid synthesis/metabolism. Due to the pandemic spread of antibiotic resistant bacteria, it is imperative to continue the search for new therapeutic agents …


A Novel Abi-Domain Protein Controls Virulence Determinant Production In Staphylococcus Aureus, Stephanie Michelle Marroquin Mar 2017

A Novel Abi-Domain Protein Controls Virulence Determinant Production In Staphylococcus Aureus, Stephanie Michelle Marroquin

USF Tampa Graduate Theses and Dissertations

A major factor in the success of Staphylococcus aureus as a pathogen is its vast arsenal of virulence determinants and, more importantly, the tight and precisely- timed regulation of these factors. Here we investigate the product of the S. aureus gene, SAUSA300_1984, encoding a putative transmembrane protein. This as yet uncharacterized protein belongs to the Abi (abortive infection) family, which are commonly annotated as CAAX-proteases, and are significantly understudied in prokaryotes. In S. aureus the disruption of SAUSA300_1984 results in a drastic reduction of proteolytic and hemolytic activity, as well as diminished pigmentation. This phenotype appears to be mediated through …


Diversity And Biocide Susceptibility Of Fungal Assemblages Dwelling In The Art Gallery Of Magura Cave, Bulgaria, Milena M. Mitova, Mihail Iliev, Alena Nováková, Anna A. Gorbushina, Veneta I. Groudeva, Pedro M. Martin-Sanchez Feb 2017

Diversity And Biocide Susceptibility Of Fungal Assemblages Dwelling In The Art Gallery Of Magura Cave, Bulgaria, Milena M. Mitova, Mihail Iliev, Alena Nováková, Anna A. Gorbushina, Veneta I. Groudeva, Pedro M. Martin-Sanchez

International Journal of Speleology

Magura Cave, north-western Bulgaria, possesses valuable rock-art paintings made with bat guano and dated from the period between the Eneolithic and Bronze Ages. Since 2008, the Art Gallery is closed to the general public in order to protect the paintings from vandalism, microclimatic changes caused by visitors and artificial illumination, and the consequent growth of fungi and phototrophs. Nevertheless, some tourist visits are allowed under the supervision of cave managers. This study provides the first scientific report on cultivable fungal assemblages dwelling different substrata in the Art Gallery. A total of 78 strains, belonging to 37 OTUs (Ascomycota 81%, Zygomycota …


A Family Of Genus-Specific Rnas In Tandem With Dna-Binding Proteins Control Expression Of The Bada Major Virulence Factor Gene In Bartonella Henselae, Nhan Tu, Ronan K. Carroll, Andy Weiss, Lindsey N. Shaw, Gael Nicolas, Sarah Thomas, Amorce Lima, Udoka Okaro, Burt Anderson Jan 2017

A Family Of Genus-Specific Rnas In Tandem With Dna-Binding Proteins Control Expression Of The Bada Major Virulence Factor Gene In Bartonella Henselae, Nhan Tu, Ronan K. Carroll, Andy Weiss, Lindsey N. Shaw, Gael Nicolas, Sarah Thomas, Amorce Lima, Udoka Okaro, Burt Anderson

Molecular Biosciences Faculty Publications

Bartonella henselae is a gram-negative zoonotic bacterium that causes infections in humans including endocarditis and bacillary angiomatosis. B. henselae has been shown to grow as large aggregates and form biofilms in vitro. The aggregative growth and the angiogenic host response requires the trimeric autotransporter adhesin BadA. We examined the transcriptome of the Houston-1 strain of B. henselae using RNA-seq revealing nine novel, highly-expressed intergenic transcripts (Bartonella regulatory transcript, Brt1-9). The Brt family of RNAs is unique to the genus Bartonella and ranges from 194 to 203 nucleotides with high homology and stable predicted secondary structures. Immediately downstream of each …


Towards The Complete Proteinaceous Regulome Of Acinetobacter Baumannii, Leila G. Casella, Andy Weiss, Ernesto Pérez-Rueda, J Antonio Ibarra, Lindsey N. Shaw Jan 2017

Towards The Complete Proteinaceous Regulome Of Acinetobacter Baumannii, Leila G. Casella, Andy Weiss, Ernesto Pérez-Rueda, J Antonio Ibarra, Lindsey N. Shaw

Molecular Biosciences Faculty Publications

The emergence of Acinetobacter baumannii strains, with broad multidrug-resistance phenotypes and novel virulence factors unique to hypervirulent strains, presents a major threat to human health worldwide. Although a number of studies have described virulence-affecting entities for this organism, very few have identified regulatory elements controlling their expression. Previously, our group has documented the global identification and curation of regulatory RNAs in A. baumannii. As such, in the present study, we detail an extension of this work, the performance of an extensive bioinformatic analysis to identify regulatory proteins in the recently annotated genome of the highly virulent AB5075 strain. In so …