May 8, 2015

NicVAX Vaccine as an Effective Smoking Cessation Aid

Tavia Buysse '15

NicVAX is a vaccine developed to help individuals quit smoking. The vaccine is designed to cause a person’s immune system to develop antibodies to nicotine. When a person smokes and nicotine is introduced to their bloodstream, antibodies will bind to it and prevent the chemical from crossing the blood-brain barrier. Thus, the individual will obtain no stimulatory effect from smoking cigarettes. A randomized, double-blind, placebo-controlled phase II clinical trial was conducted to determine if a higher response to the vaccine was associated with higher smoking abstinence rates. The study also tested different doses and administration frequencies of the vaccine to determine the best way to elicit a higher immune response. Vaccine recipients with the highest anti-nicotine antibody response to the vaccine were found to be significantly more likely to remain abstinent from smoking for a period of 8 weeks than placebo recipients. A treatment schedule of 5 injections at a dose of 400 µg was found to elicit the greatest immune response. The study established that NicVAX vaccine leads to the production of anti-nicotine antibodies and is associated with increased smoking abstinence in recipients. Therefore, further research on the vaccine as a smoking cessation aid is justified.

Potential Horizontal Gene Transfer of Antibiotic Resistant Staphylococcus Within Ready-to-Eat Food

Emmett Hwee '15

Any bacterium is capable of increasing the spread of antibiotic resistant genes, thanks to horizontal gene transfer. Even a “good” nonpathogenic strain of bacteria could hypothetically assist in the transfer of antibiotic resistance; possibly giving the most threatening and virulent strain of bacteria the ability to fend off one of modern man’s main method of defense. Ready to eat (RTE) food which does not need thermal processing before consumption could be a possible vehicle for the spread of antibiotic resistant microorganisms, specifically in the Genus Staphylococcus. The presence of Staphylococcus bacteria is routinely detected in RTE food (as a safe level in microbiology safety-checks) however its degree of antibiotic resistant within RTE foodstuffs is rarely investigated. The study by Wioleta Chajęcka-Wierzchowska and company had evaluated the phenotypic antibiotic resistance of Staphylococcus spp. taken from various retail products in Olsztyn, Poland. From the local markets 853 different RTE foods were sampled; out of all food samples, 113 tested positive for Staphylococcus, and out of those Staph. isolates, 54.9% tested a positive resistance for at least one type of antibiotic. Out of the antibiotics tested, most of the isolates were resistant to cefoxitin, followed by clindamycin, tigecycline, quinupristin-dalfopristin, rifampin, tetracycline, and erythromycin. Out of all 62 strains that were resistant to at least one antibiotic, three genetic tetracycline resistance determinants were tracked; 38 harbored the tet(M) gene, 24 harbored tet(L) gene and 9 had the tet(K) gene. Of the 38 strains containing tet(M), 13 of them tested positive for the Tn916-Tn1545-like integrase family gene, a transposon element (assisting in horizontal gene transfer). These results suggest that retail ready to eat food could be considered an important route in the transmission of multiple antibiotic resistant genes however further study is needed for a conclusion.

Xenopus Laevis scare response to tank size

Neil Hanson '15

Many animals respond to predator attacks, cues or even some signals from conspecific kin with behaviors directed towards survival. Some animals exclusively fight, flee, or signal to their enemies, but what about animals that have more than one means of anti-predator behaviors in their arsenal? This raises the question of what conditions does an animal display a certain behavior over the other? The african clawed frog Xenopus Laevis, is one of these animals that displays multiple anti-predator behaviors and lives in a variety of aquatic environments. The aim of this study is to determine if anti-predator behavior is determined by habitat size. We observed the scare reactions of 10 individual Xenopus laevis in different sized tanks. Frogs displayed “darting” behavior marginally significantly more in large tank than in the small tank. Difference in tank size was found to have no significant difference in “tucking” behavior. Vegetation density in environment could have a factor in behavior choice, though further studies are needed to explore this.