Microbiology Commons^™

Regulation Of The Vapbc-1 Toxin-Antitoxin Locus In Nontypeable Haemophilus Influenzae, Susan D. Cline, Sehresh Saleem, Dayle A. Daines

Biological Sciences Faculty Publications

Nontypeable Haemophilus influenzae (NTHi) are human-adapted commensal bacteria that can cause a number of chronic mucosal infections, including otitis media and bronchitis. One way for these organisms to survive antibiotic therapy and cause recurrent disease is to stop replicating, as most antimicrobials target essential biosynthetic pathways. Toxin-antitoxin (TA) gene pairs have been shown to facilitate entry into a reversible bacteriostatic state. Characteristically, these operons encode a protein toxin and an antitoxin that associate following translation to form a nontoxic complex, which then binds to and regulates the cognate TA promoter. Under stressful conditions, the labile antitoxin is degraded and the …

Links From Mantle To Microbe At The Lau Integrated Study Site: Insights From A Back-Arc Spreading Center, Margaret K. Tivey, Erin Becker, Roxanne Beinart, Charles R. Fisher, Peter Girguis, Charles H. Langmuir, Peter J. Michael, Anna-Louise Reysenbach

Biology Faculty Publications and Presentations

The Lau Integrated Study Site (ISS) has provided unique opportunities for study of ridge processes because of its back-arc setting in the southwestern Pacific. Its location allows study of a biogeographical province distinct from those of eastern Pacific and mid-Atlantic ridges, and crustal compositions along the ridge lie outside the range of mid-ocean ridge crustal compositions. The Lau ISS is located above a subduction zone, at an oblique angle. The underlying mantle receives water and other elements derived from the downgoing lithospheric slab, with an increase in slab influence from north to south. Water lowers the mantle melting temperature and …

Antifungal Activity Of Lactobacillus Against Microsporum Canis, Microsporum Gypseum And Epidermophyton Floccosum, Jiahui Guo, Brid Brosnan, Ambrose Furey, Elke K. Arendt, Padraigin Murphy

Department of Biological Sciences Publications

A total of 220 lactic acid bacteria isolates were screened for antifungal activity using Aspergillus fumigatus and Aspergillus niger as the target strains. Four Lactobacillus strains exhibited strong inhibitory activity on agar surfaces. All four were also identified as having strong inhibitory activity against the human pathogenic fungi Microsporum canis, Microsporum gypseum and Epidermophyton floccosum. One of the four lactobacilli, namely Lb. reuteri ee1p exhibited the most inhibition against dermatophytes. Cell-free culture supernatants of Lb. reuteri ee1p and of the non-antifungal Lb. reuteri M13 were freeze-dried and used to access and compare antifungal activity in agar plate assays …

Bacteria And Fungi Cultured From Sand, Cloacal Fluids, And Unhatched Eggs Of Olive Ridley Sea Turtles And Standard Testing Of Antimicrobial Properties Of Cloacal Fluids, Erin Keene, Tanya Soule, Frank Paladino

Tanya Soule

No abstract provided.

Composition And Methods For Detecting, Treating, And Protecting Against Fusobacterium Infection. United States Patent Application Pct/Us2012/030576 Filed March 26, 2012, Amit Kumar, Dvm, Ms, Phd

Amit Kumar, DVM, MS, PhD

A protein that helps Fusobacterium necrophorum to attach to eukaryotic host cells has been identified. The protein has been shown to have potential to be a vaccine candidate in in vitro and in vivo experiments.

Genetic Reporter System For Positioning Of Proteins At The Bacterial Pole, Kathryn R. Fixen, Anuradha Janakiraman, Sean Garritty, Daniel J. Slade, Andrew N. Gray, Nilay Karahan, Ann Hochschild, Marcia C. Goldberg

Publications and Research

Spatial organization within bacteria is fundamental to many cellular processes, although the basic mechanisms underlying localization of proteins to specific sites within bacteria are poorly understood. The study of protein positioning has been limited by a paucity of methods that allow rapid large-scale screening for mutants in which protein positioning is altered. We developed a genetic reporter system for protein localization to the pole within the bacterial cytoplasm that allows saturation screening for mutants in Escherichia coli in which protein localization is altered. Utilizing this system, we identify proteins required for proper positioning of the Shigella autotransporter IcsA. Autotransporters, widely …

Partial Characterization Of The Antimicrobial Activity Of Ccl28, Bin Liu

Theses and Dissertations

This research focuses on the antimicrobial activity of the mouse chemokine CCL28. In addition to their well characterized chemotactic activity, many chemokines have been shown to be antimicrobial in vitro, including the mucosally expressed chemokine CCL28. I have investigated the primary sequence features required for antimicrobial activity, salt sensitive nature of killing/binding mechanism, and in vivo microbial interactions of CCL28. Through the use of protein mutation and expression techniques, I have shown that the holoprotein (108 amino acids) is necessary for full antimicrobial activity of CCL28. Furthermore, the C terminal region of CCL28 is essential for microbial killing as an …

Molecular Diagnostics: The Changing Culture Of Medical Microbiology, Susan Bullman, Brigid Lucey, Roy D. Sleator

Department of Biological Sciences Publications

Diagnostic molecular biology is arguably the fastest growing area in current laboratory-based medicine. Growth of the so called ‘omics’ technologies has, over the last decade, led to a gradual migration away from the ‘one test, one pathogen’ paradigm, toward multiplex approaches to infectious disease diagnosis, which have led to significant improvements in clinical diagnostics and ultimately improved patient care.

Humanized Mice As A Model To Study Human Viral Pathogenesis And Novel Antiviral Drugs, Freddy Mauricio Sanchez Tumbaco

Theses and Dissertations

Animal models have greatly contributed to the understanding of different aspects of human biology, as well as a variety of human-related pathogens and diseases. In order to study them, humanized mice susceptible to pathogens that replicate in human immune cells have been developed (e.g., humanized Rag2-/-γc-/- mice). These animals are engrafted with human hematopoietic stem cells (HSCs), resulting in the de novo development and maturation of the major functional components of the human adaptive immune system and the production of a variety of human cell types. Primary and secondary lymphoid organs in the mouse are populated with human cells, and …

Biological Conversion Assay Using Clostridium Phytofermentans To Estimate Plant Feedstock Quality, Scott J. Lee, Thomas A. Warnick, Sivakumar Pattathil, Jesus G. Alvelo-Maurosa, Michelle J. Serapiglia, Heather Mccormick, Virginia Brown, Naomi F. Young, Danny J. Schnell, Lawrence B. Smart, Michael G. Hahn, Jeffrey F. Pedersen, Susan Leschine, Samuel P. Hazen

Susan Leschine

Background There is currently considerable interest in developing renewable sources of energy. One strategy is the biological conversion of plant biomass to liquid transportation fuel. Several technical hurdles impinge upon the economic feasibility of this strategy, including the development of energy crops amenable to facile deconstruction. Reliable assays to characterize feedstock quality are needed to measure the effects of pre-treatment and processing and of the plant and microbial genetic diversity that influence bioconversion efficiency. Results We used the anaerobic bacterium Clostridium phytofermentans to develop a robust assay for biomass digestibility and conversion to biofuels. The assay utilizes the ability of …

Biological Conversion Assay Using Clostridium Phytofermentans To Estimate Plant Feedstock Quality, Scott Lee, Thomas Warnick, Sivakumar Pattathil, Jesus Alvelo-Maurosa, Michelle Serapiglia, Heathers Mccormick, Virginia Brown, Naomi Young, Danny Schnell, Lawrence Smart, Michael Hahn, Jeffrey Pedersen, Susan Leschine, Samuel Hazen

Thomas A Warnick

No abstract provided.

Comment On “On Electrical Conductivity Of Microbial Nanowires And Biofilms” By S. M. Strycharz-Glaven, R. M. Snider, A. Guiseppi-Elie And L. M. Tender, Energy Environ. Sci., 2011, 4, 4366, Nikhil S. Malvankar, Mark T. Tuominen, Derek Lovley

Derek Lovley

A paper published in Energy and Environmental Science by Strycharz-Glaven et al. suggests that electron transport along the pili and through the conductive biofilms of Geobacter sulfurreducens proceeds via electron superexchange rather than metallic-like conductivity. Multiple lines of evidence disprove the superexchange hypothesis, but are consistent with metallic-like conductivity.

Bioavailability Of Jarosite For Stimulating Acid Mine Drainage Attenuation, Klaus R. Nusslein

Klaus R. Nusslein

Biological reduction of iron-sulfate minerals, such as jarosite, has the potential to contribute to the natural attenuation of acid mine drainage (AMD) sites. Previous studies of AMD attenuation at Davis Mine, an abandoned pyrite mine in Rowe Massachusetts, provided evidence of iron and sulfate reduction by indigenous bacteria. Jarosite is a large component of the sediment at Davis Mine and may play a role in AMD attenuation. In this study, microcosms were constructed with groundwater and sediment from Davis Mine and amended with glycerol, nitrogen and phosphorus (GNP) and naturally formed natrojarosite. Over time, higher total iron, sulfate, pH and …

Pseudomonas Fluorescens Hk44: Lessons Learned From A Model Whole-Cell Bioreporter With A Broad Application History, Josef Trögl, Archana Chauhan, Steven Ripp, Alice C. Layton, Gabriela Kuncová, Gary S. Sayler

Gary S. Sayler

Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE) phenotype directly linked to a catabolic (naphthalene degradative) pathway. HK44 was the first genetically engineered microorganism to be released in the field to monitor bioremediation potential. Subsequent to that release, strain HK44 had been introduced into other solids (soils, sands), liquid (water, wastewater), and volatile environments. In these matrices, it has functioned as one of the best characterized chemically-responsive environmental bioreporters and as a model organism for understanding bacterial colonization and transport, cell immobilization strategies, and the kinetics of cellular bioluminescent …

Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Swarna Jaiswal, Brendan Duffy, Patrick Mchale

Articles

The colonisation of clinical and industrial surfaces with microorganisms, including antibiotic-resistant strains, has promoted increased research into the development of effective antibacterial and antifouling coatings. This study describes the preparation of metal nitrate (Ag, Cu, Zn) doped methyltriethoxysilane (MTEOS) coatings and the rapid assessment of their antibacterial activity using polyproylene microtitre plates. Microtitre plate wells were coated with different volumes of liquid sol–gel and cured under various conditions. Curing parameters were analysed by thermogravimetric analysis (TGA) and visual examination. The optimum curing conditions were determined to be 50–70 °C using a volume of 200 μl. The coated wells were challenged …

Emerging Viruses In The Felidae: Shifting Paradigms, Stephen J. O'Brien, Jennifer L. Troyer, Meredith Brown, Warren E. Johnson, Agostinho Antunes, Melody E. Roelke, Jill Pecon-Slattery

Biology Faculty Articles

The domestic cat is afflicted with multiple viruses that serve as powerful models for human disease including cancers, SARS and HIV/AIDS. Cat viruses that cause these diseases have been studied for decades revealing detailed insight concerning transmission, virulence, origins and pathogenesis. Here we review recent genetic advances that have questioned traditional wisdom regarding the origins of virulent Feline infectious peritonitis (FIP) diseases, the pathogenic potential of Feline Immunodeficiency Virus (FIV) in wild non-domestic Felidae species, and the restriction of Feline Leukemia Virus (FeLV) mediated immune impairment to domestic cats rather than other Felidae species. The most recent interpretations indicate important …

Leptospire Genomic Diversity Revealed By Microarray-Based Comparative Genomic Hybridization, Broderick Eribo, Sirima Mingmongkolchai, Tingfen Yan, Padunsri Dubbs, Karen Nelson

Department of Biology Faculty Publications

Comparative genomic hybridization was used to compare genetic diversity of five strains of Leptospira (Leptospira interrogans serovars Bratislava, Canicola, and Hebdomadis and Leptospira kirschneri serovars Cynopteri and Grippotyphosa). The array was designed based on two available sequenced Leptospira reference genomes, those of L. interrogans serovar Copenhageni and L. interrogans serovar Lai. A comparison of genetic contents showed that L. interrogans serovar Bratislava was closest to the reference genomes while L. kirschneri serovar Grippotyphosa had the least similarity to the reference genomes. Cluster analysis indicated that L. interrogans serovars Bratislava and Hebdomadis clustered together first, followed by L. interrogans serovar Canicola, …

Leptospire Genomic Diversity Revealed By Microarray-Based Comparative Genomic Hybridization, Broderick Eribo, Sirima Mingmongkolchai, Tingfen Yan, Padunsri Dubbs, Karen E. Nelson

Broderick Eribo

Desiccation Induces Viable But Non-Culturable Cells In Sinorhizobium Melilioti 1021, Klaus R. Nusslein, Frans J. De Bruijn, Jan Ac Vriezen

Klaus R. Nusslein

Sinorhizobium meliloti is a microorganism commercially used in the production of e.g. Medicago sativa seed inocula. Many inocula are powder-based and production includes a drying step. Although S. meliloti survives drying well, the quality of the inocula is reduced during this process. In this study we determined survival during desiccation of the commercial strains 102F84 and 102F85 as well as the model strain USDA1021. The survival of S. meliloti 1021 was estimated during nine weeks at 22% relative humidity. We found that after an initial rapid decline of colony forming units, the decline slowed to a steady 10-fold reduction in …

Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen

Pr. Mamoudou H. DICKO, PhD

The antimicrobial activity of 8 Bacillus spp. and 2 Lysinibacillus spp. representing the predominant aerobic sporeformers during traditional maari fermentations, a traditional fermented baobab seeds product fromBurkina Faso,was investigated. The antimicrobial activitywas assessed against a total of 31 indicator organisms representing various Gram-negative and positive pathogens. The screening showed that 3 Bacillus subtilis strains (B3, B122 and B222) in particular had antimicrobial activity against some Gram-positive organisms and were selected for further studies. Itwas found that the antimicrobial substances producedwere heat stable, in-sensitive to catalase, sensitive to protease and trypsin but resistant to the proteolytic action of papain and proteinase …