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Full-Text Articles in Organisms
Impacts Of A Duf2207 Family Protein On Streptococcus Mutans Stress Tolerance Responses And Biofilm Formation, Xiaochang Huang, Camile G. Laird, Paul P. Riley, Zezhang Tom Wen
Impacts Of A Duf2207 Family Protein On Streptococcus Mutans Stress Tolerance Responses And Biofilm Formation, Xiaochang Huang, Camile G. Laird, Paul P. Riley, Zezhang Tom Wen
School of Dentistry Faculty Publications
Locus SMU.243 in Streptococcus mutans was annotated as a member of the DUF2207 family proteins highly conserved in all bacteria but with unknown function. To investigate its role in S. mutans physiology, a SMU.243-deficient mutant was constructed using allelic exchange mutagenesis, and the impacts of SMU.243 deletion on bacterial growth, stress tolerance response, and biofilm formation were analyzed. Compared to the wild-type UA159, S. mutans lacking SMU.243 displayed a reduced growth rate and a reduced overnight culture density (p < 0.01) when grown at low pH and in the presence of methyl viologen. Relative to the parent strain, the deficient mutant also had a reduced survival rate following incubation in a buffer of pH 2.8 (p < 0.01) and in a buffer containing hydrogen peroxide at 58 mM after 60 min (p < 0.001) and had a reduced capacity in biofilm formation especially in the presence of sucrose (p < 0.01). To study any ensuing functional/phenotypical links between SMU.243 and uppP, which is located immediately downstream of SMU.243 and encodes an undecaprenyl pyrophosphate phosphatase involved in recycling of carrier lipid undecaprenyl phosphate, a uppP deficient mutant was generated using allelic exchange mutagenesis. Unlike the SMU.243 mutant, deletion of uppP affected cell envelope biogenesis and caused major increases in susceptibility to bacitracin. In addition, two variant morphological mutants, one forming rough colonies and the other forming mucoid, smooth colonies, also emerged following the deletion of uppP. The results suggest that the SMU.243-encoded protein of the DUF2207 family in S. mutans plays an important role in stress tolerance response and biofilm formation, but unlike the downstream uppP, does not seem to be involved in cell envelope biogenesis, although the exact roles in S. mutans’ physiology awaits further investigation.
Investigating The Antibacterial And Immunomodulatory Properties Of Lactobacillus Acidophilus Postbiotics, Rachael M. Wilson
Investigating The Antibacterial And Immunomodulatory Properties Of Lactobacillus Acidophilus Postbiotics, Rachael M. Wilson
Graduate School of Biomedical Sciences Theses and Dissertations
Probiotics are nonpathogenic microorganisms that have been extensively studied for their ability to prevent various infectious, gastrointestinal, and autoimmune diseases. The mechanisms underlying these probiotic effects have not been elucidated. However, we and other researchers have evidence suggesting that probiotic bacteria secrete metabolites that are antimicrobial and anti-inflammatory. As such, we developed a methodology to collect the secreted metabolites from a probiotic bacterium, Lactobacillus acidophilus, and tested this cell free filtrate (CFF) both in vitro and in vivo. Using this CFF, we have demonstrated that L. acidophilus secretes a molecule(s) that has specific bactericidal activity against the opportunistic pathogen, Pseudomonas …
Safety And Efficacy Of Silver-Coated Biomaterials In Vivo, Megan Klem, Darien L. Seidman, Rahyan Mahmoud, Manuella Adu, Lei Yu, Jeffrey Hettinger, Renee M Demarest
Safety And Efficacy Of Silver-Coated Biomaterials In Vivo, Megan Klem, Darien L. Seidman, Rahyan Mahmoud, Manuella Adu, Lei Yu, Jeffrey Hettinger, Renee M Demarest
Rowan-Virtua Research Day
Overtreatment and overuse of antibiotics in healthcare and agricultural settings have contributed to the selective pressure on bacterial strains to develop resistance. Resistance can develop as a result of mutations and subsequent resistance genes that allow bacteria to survive against antibiotics. Novel silver-oxide coatings were developed and were previously demonstrated to prevent adhesion of gram-negative bacteria (Escherichia Coli and Pseudomonas Aeruginosa) to the disc, but did not prevent gram-positive bacterial adherence (Streptococcus Aureus). In order to determine whether the silver-oxide coatings are bacterial static and may be preventing progression to biofilm formation, in vivo analysis of S. Aureus attached to …
Deciphering The Mechanisms Of Alcaligenes Faecalis’ Inhibition Of Staphylococcus Aureus And Synergism With Antibiotics, Cortlyn Holdren
Deciphering The Mechanisms Of Alcaligenes Faecalis’ Inhibition Of Staphylococcus Aureus And Synergism With Antibiotics, Cortlyn Holdren
Undergraduate Honors Theses
Staphylococcus aureus has developed resistance to several antibiotics including vancomycin, which is often used as a “last resort” treatment. There is an ever-increasing need to develop novel antimicrobial treatments to combat S. aureus and other drug resistant bacteria. Microorganisms are most often found in polymicrobial communities where they either exhibit synergistic or antagonistic relationships. Competition between microorganisms can lead to the discovery of new antimicrobial targets as the specific mechanisms of resistance are elucidated. In addition, synergistic treatments are being evaluated for their combined effect and potential to decrease the concentration of drugs needed, and thus the side effects also. …
The Effect Of Alcaligenes Faecalis On Inhibition Of Candida Albicans Biofilm And Planktonic Growth, Nausheen A. Siddiqui
The Effect Of Alcaligenes Faecalis On Inhibition Of Candida Albicans Biofilm And Planktonic Growth, Nausheen A. Siddiqui
Undergraduate Honors Theses
Candida albicans is a fungal microorganism found on the human body and in the environment. An opportunistic pathogen causing local and systemic infection, this fungus is one of the leading causes of nosocomial infections. More alarming is its growing resistance against the limited number of antifungals we have for treatment Candida infections. An area of current research, termed polymicrobial interactions, focuses on how different microorganisms interact with each other for limited space, nutrients, and survival. The current study focuses on attempting to inhibit planktonic and biofilm growth stages by using the benign bacterium Alcaligenes faecalis, previously shown in our …
Fatty Acid Mediated Alterations In Biofilm Formation With Vibrio Cholerae, Isabel Gray
Fatty Acid Mediated Alterations In Biofilm Formation With Vibrio Cholerae, Isabel Gray
Honors Theses
Vibrio cholerae is a Gram-negative bacterium known as a waterborne pathogen. It is often found in marine conditions and can infect humans through ingestion. V. cholerae is responsible for cholera, a disease characterized by profuse diarrhea, vomiting, and other dehydration symptoms. Ultimately, severe cases can cause extreme electrolyte imbalances, shock, and acute renal failure which lead to death in a short period of time. Annually, V. cholerae causes approximately 3 million cases of cholera and 100,000 deaths worldwide. V. cholerae can persist in motile and biofilm lifestyles under aquatic and host conditions, a unique biphasic lifestyle that contributes to Vibrio’s …
Investigation Of The In Vitro Interactions Between Two Common Cystic Fibrosis Pathogens, Staphylococcus Aureus And Stenotrophomonas Maltophilia., Matthew Hill
College of Arts & Sciences Senior Honors Theses
Cystic Fibrosis (CF) is one of the most common autosomal disorders in Caucasian populations. This disorder creates a very opportune environment for many pathogens within the patient’s lung. Two common pathogens that infect CF patient’s lungs are Staphylococcus aureusand Stenotrophomonas maltophilia. These two species of bacteria can colonize host environments and establish mats of cells known as biofilms that become very difficult to eradicate with antibiotics. Once inside a CF lung, these pathogens must not only evade the host immune response but they also interact and compete with each other; however, how bacterial pathogens interact inside the host lung …
Are Cdi Systems Multicolored, Facultative, Helping Greenbeards?, Elizabeth S. Danka, Erin C. Garcia, Peggy A. Cotter
Are Cdi Systems Multicolored, Facultative, Helping Greenbeards?, Elizabeth S. Danka, Erin C. Garcia, Peggy A. Cotter
Microbiology, Immunology, and Molecular Genetics Faculty Publications
Competitive and cooperative interactions between organisms, including bacteria, can significantly impact the composition of a community and the fitness of its members, as well as the fitness of their hosts when communities are living on or within other organisms. Understanding the underlying mechanisms is critical to the development of strategies to control microbiological communities that impact animal and plant health and also for understanding the evolution of social behaviors, which has been challenging for evolutionary biologists. Contact-dependent growth inhibition (CDI) is a phenomenon defined by the delivery of a protein toxin to the cytoplasm of neighboring bacteria upon cell–cell contact, …