February 13, 2015

Exercise a Pain in the Gut? Effects of L-Citrulline on Splanchnic Perfusion and Gut Injury

Will Warmka '15

During bouts of intense exercise, the human body undergoes many physiological changes. A major physiological response is the directing blood flow away from visceral organs. This is important in that it ensures major muscles groups receive enough oxygen to meet the energy demands of intense exercise. The resulting loss of blood flow from the splanchnic region can cause discomfort, pain, injury, as well as other gastrointestinal symptoms. In light of this, a study was performed by Van Wijck to determine the effects of L-citrulline had on splanchnic perfusion. There were ten male participants that cycled at 70% of maximum workload and had pre-workout supplementation of L-alanine (placebo) or L-citrulline. The study was conducted in a randomized, double-blind manner. They assessed perfusion with gastric air tonometry and microcirculation was assessed using sidestream dark field imaging. Their results show pre-exercise L-citrulline intake prevents splanchnic hypoperfusion and protects against intestinal injury compared to the placebo. Based on these findings the next step should be to determine other advantages L-citrulline supplementation may possess such as improved nutrient uptake and improved early recovery.

Understanding the Molecular Mechanisms of Maize Response to Repeated Chilling Stress: A 'Priming' Study

Natalia Wiatros '15

As global warming becomes more prominent, there is increased threat to the sustainability of corn production due to the crop’s inability to withstand changes in abiotic factors of drought, salinity, ultraviolet radiation damage, and temperature fluctuation (Mittler, 2006). Of late, there have been findings that maize may have the ability to respond to stress factors faster if previously exposed to the factor. In a recent study of recurring dehydration stresses, Arabidopsis demonstrated “trainable genes”, where increased rates of transcription of stress-response genes were triggered (Ding, 2012). This indicates the plausibility that previous exposure can result in decreased susceptibility to damage from abiotic stress. This experiment included subjecting Maize lines B73, Mo17, Oh43, and MoG to discern whether early exposure to cold-stress would result in decreased susceptibility to damage in Maize plants, and to identify possible Maize effector genes assisting in the decrease of damage to ‘primed’ plants. In order to do this, a ‘priming’ protocol was developed, wherein Mo17 and MoG plants were exposed to cold at both days 8 and 9 of development. These ‘primed’ plants and plants that were not ‘primed’ were subjected to cold-stress on day 14 of development. After cold-stress, plant appearance was observed and leaf tissue collected. RNA was extracted from leaf tissue and converted to cDNA. Finally, qPCR was performed to analyze the transcription rates of (GRMZM2G124011 and AC210204.3_FG002) genes in response to cold-stress. Although significant differences in appearance were not visible, variation of transcription rates of selected genes between ‘primed’ and control plants suggest success of ‘priming’ concept. Further investigation regarding ‘priming’ and cold-stress will be conducted, including RNA-sequencing of ‘primed’ and cold-stressed plants.

Inhibition of Ebola Virus Using Selective Estrogen Receptor Modulators

Rachael Mills '15

Ebola viruses are members of the Filoviridae family that were first discovered in 1976 when an outbreak occurred in Zaire. In areas where Ebola infections happen, there are often high mortality rates due to hemorrhagic fever. At this time, there are no known treatments or vaccines for any strain of Ebola virus. In their work “FDA-Approved Selective Estrogen Receptor Modulators Inhibit Ebola Virus Infection,” Johansen et al. performed an in vitro, high throughput screen of already approved FDA drugs to test for antiviral activity against Zaire ebolavirus. A number of Selective Estrogen Receptor Modulators (SERMs), including clomiphene and toremifene, demonstrated the ability to inhibit viral activity. Johansen et al. then conducted an in vivo procedure using a mouse model to further verify the results of the high throughput screen. Clomiphene and toremifene both demonstrated statistically significant antiviral activity in vivo against a mouse-adapted strain of Ebola virus. Interestingly, Johansen et al. did not find any significant different in results based on the presence or absence of estrogen receptors in either their in vitro or in vivo trials. This suggests that clomiphene and toremifene are inhibiting the virus through a mechanism that is different than their known FDA-approved function. Further research is necessary in order to determine the exact method of SERMs that results in antiviral activity against Ebola viruses. The results of Johansen et al.’s high throughput screen of FDA-approved drugs and the further verification of antiviral activity characteristics of clomiphene and toremifene can be used as a platform for further research in an effort to develop a successful human treatment for Ebola virus infections.