Organisms Commons^™

Harnessing Antagonistic Pleiotropy: Tolc-Dependent Coliphages Can Drive Reduced Antibiotic Resistance In E. Coli, Cooper Mckenna

CMC Senior Theses

The rise of multidrug-resistant (MDR) bacterial pathogens has been a growing concern in healthcare around the world, and bacteriophage (phage) therapy is a promising method to combat MDR infections. One defense mechanism of E. coli against antibiotics is the TolC-AcrAB efflux pump. At the same time, some phages use TolC as a surface receptor to infect the cell. This puts TolC at a crossroads in which it is beneficial to the bacteria to protect against antibiotics but harmful by allowing phage infection, creating the potential for evolutionary trade-offs. Previous research has identified only three TolC-dependent phages and shown phage-resistant E. …

Gut Dysbiosis Correlates With Covid-19 Severity, Ednita Escobar

CMC Senior Theses

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) impacts not only respiratory but also gut and oral microbiomes, influencing the manifestations of COVID-19. Each person’s unique microbiome consists of microorganisms such as bacteria, fungi, and viruses, some of which are symbiotic and others potentially harmful. Alterations in the gut microbiome, specifically, can affect the severity and symptoms of COVID-19. A review of studies indicate a pattern of gut dysbiosis in COVID-19 patients characterized by a decrease in beneficial microbiota and/or an increase in opportunistic pathogens. This gut imbalance correlates with disease severity, suggesting that the gut microbiome plays a significant role …

Antifungal Defense Molecules From Bacterial Symbionts Of North American Trachymyrmex Ants, Georgia Scherer

CMC Senior Theses

Defensive symbioses, in which microbes provide molecular defenses for an animal host, hold great potential as untapped sources of therapeutically useful antibiotics. Fungus-growing ants use antifungal defenses from bacterial symbionts to suppress pathogenic fungi in their nests. Preliminary chemical investigations of symbiotic bacteria from this large family of ants have uncovered novel antifungal molecules with therapeutic potential, such as dentigerumycin and selvamicin.

In this study, the bacterial symbionts of North American Trachymyrmex fungus-growing ants are investigated for antifungal molecules. Plate-based bioassays using ecologically-relevant fungal pathogens confirmed that these bacteria have antifungal activity. In order to purify and identify the antifungal …

Aedes Aegypti And Dengue In The Philippines: Centering History And Critiquing Ecological And Public Health Approaches To Mosquito-Borne Disease In The Greater Asian Pacific, Maria R. Pettis

Pomona Senior Theses

The global incidence of dengue has increase 30-fold over the past 50 years in the western or Asian Pacific, this region is also a contemporary epicenter for resource extraction and ecological destabilization. Dengue is addition to yellow fever, chikungunya and most recently zika virus, are transmitted by the mosquito vector Aedes aegypti- a domesticated mosquito adept at breeding in artificial household containers and within homes. The history of the domestication and global distribution of Aedes aegypti is intrinsically linked to European expansion into and among tropical worlds. Contemporary population genetics research suggest the westward expansion of the mosquito vector …

Thermal Selection In Sceloporus Occidentalis During Exercise Recovery, Morgan A. Halley

Scripps Senior Theses

Ectotherms regulate body temperature (T_b) primarily through behavioral interactions with their environment. These animals also have limited aerobic scopes and must rely on anaerobic metabolism to support intense activity; lactate byproduct and glycogen depletion are two consequences of anaerobic metabolism that must be dealt with during exercise recovery. It has been suggested that, in many ectothermic species, T_b may affect the rate of lactate clearance and glycogen repletion during recovery from intense exercise. This study investigated thermoregulatory behavior in Western Fence Lizards (Sceloporus occidentalis) to determine preferred T_b during exercise recovery. I hypothesized that …