Intensive agricultural practices around the world have led to both a depletion of soil organic carbon (SOC) in cropped soils and runoff of nitrogen fertilizer into the environment, which can lead to limited crop growth and environmental degradation. Because of the increasing demand for food and the decreasing vitality of soils, there is a great need for less intensive alternatives to traditional synthetic fertilizers and agricultural practices. In recent years, microalgae have been increasingly seen as a potential alternative to traditional fertilizers, with prokaryotic cyanobacteria being able to fix nitrogen for plant growth. While there is potential for eukaryotic microalgae to offer similar benefits to agricultural plants, their overall impacts are not widely known. To study the impacts that eukaryotic microalgae have on the plant rhizosphere, sixteen heads of Arianna lettuce were grown, with eight treated with Chlorella sp. algae amended to the irrigation water. The rhizosphere of the plant was sampled and the microbial community was analyzed using quantitative PCR (qPCR) in order to determine changes in rhizosphere bacterial composition, nitrogen-fixing population abundances, and Chlorella sp. abundances. It was found that the treated plants had a greater mass and a significantly greater presence of nitrogen-fixing bacteria. On the contrary, plant rhizospheres that were untreated were found to have a significantly greater overall abundance of the bacterial community. Lastly, the rhizosphere of amended plants harbored significantly more Chlorella than the untreated plants, indicating that the Chlorella was retained and possibly recruited to the plant rhizosphere throughout the treatment.

As the world’s population exponentially grows, more food production is required. This increasing food production currently has led to the un-sustainable production of chemical fertilizers and resultant overuse. A more sustainable option to enhance food production could be the use of fertilizer derived from food waste. To address this, we investigated the possibility of utilizing a fertilizer derived from food waste to grow hydroponic vegetables. Arugula (Eruca sativa) ‘Slow Bolt’ and lettuce (Lactuca sativa) ‘Cherokee’ and ‘Rex’ were cultivated using indoor deep-flow hydroponic systems at 23 ºC under a photosynthetic photon flux density of 170 µmol∙m−2∙s−1 with an 18-hour photoperiod. Plant nutrient solutions were provided by food waste fertilizer or commercial 15:5:20 NPK fertilizer at the identical electrical conductivity (EC) of 2.3 mS·cm–1. At the EC of 2.3 mS·cm–1, chemical fertilizer contained 150 ppm N, 50 ppm P, and 200 ppm K, while food waste fertilizer had 60 ppm N, 26 ppm P, and 119 ppm K. Four weeks after the nutrient treatments were implemented, compared to plants grown with chemical fertilizer, lettuce ‘Rex’ grown with food waste fertilizer had four less leaves, 27.1% shorter leaves, 68.2% and 23.1% less shoot and root fresh weight, respectively. Lettuce ‘Cherokee’ and arugula grown with food waste fertilizer followed a similar trend with fresh shoot weights that were 80.1% and 95.6% less compared to the chemical fertilizer, respectively. In general, the magnitude of reduction in the plant growth was greatest in arugula. These results suggest that both fertilizers were able to successfully grow lettuce and arugula, although the reduced plant growth with the food waste fertilizer in our study is likely from a lower concentration of nutrients when we considered EC as an indicator of nutrient concentration equivalency of the two fertilizer types.

Dental caries are considered the most common infectious diseases that impacts human populations worldwide. The human oral cavity is colonized by a wide range of microorganisms including viruses, protozoa, fungi, archaea and bacteria. Oral diseases begin with the development of dental plaque, a biofilm formed by the accumulation of bacteria. Of these bacteria, Streptococcus mutans has been identified as the leading cause of dental caries. Probiotics are described as live microorganisms which provide beneficial impacts to their host by improving the intestinal microbial balance. Studies have demonstrated that probiotic therapies may be suitable for decreasing the cariogenic potential of S. mutans as well as other cariogenic bacteria. In this study, it was hypothesized that probiotics would exhibit a significant effect on the population density of S. mutans within the oral cavity. Nine people selected in this study consumed Activia probiotic yogurt for a seven-day trial period. DNA was extracted from these swabs and analyzed by qPCR. The results showed the amount of S. mutans increased insignificantly (P>0.05), whereas the proportion of S. mutans in the entire community was insignificant (P>0.05). Individual subjects responded differently to treatment, indicating the influence of their preferential diet on S. mutans abundance. Studies conducted on the probiotic strains within the Activia yogurt were previously shown to be insufficient in antagonizing cariogenic bacteria, which attributes to these results.

Phytohemagglutinin (PHA) is a plant lectin commonly used to stimulate and test responses of the immune system and is known to induce T cell proliferation, agglutinate human leukocytes, and yield adjustments in lymphocyte populations. What is not well know is how responses to PHA correlate with a host's ability to resist or recover from pathogen invasion. This study uses information from previously published studies to determine whether or not PHA can be a good indicator of disease severity or disease resistance in a host. With PHA having the abilities that it does, immune responses to PHA may correlate with responses important for pathogen resistance and clearance. Such a relationship could only be uncovered if in vivo or in vitro responses to PHA are measured and, independent from the PHA challenge, symptoms and/or mortality rates of hosts are documented after pathogen exposure. An in vitro response can be detected by measuring cellular proliferation in response to PHA followed by separate cell cultures exposed to a pathogen. While an in vivo response can be detected by measuring variation in swelling in response to an injection of PHA. In reviewing a broad range of articles that meet my criteria, the majority of articles failed to show a strong relationship between PHA and disease severity or disease resistance. Therefore, immunologists must consider the usefulness of the PHA tests as a measure of immunocompetence, which is a host's ability to predict response to a pathogen. According to the literature, using PHA does not predict responses to pathogen invasion. However, it is possible that with carefully designed experiments, it could be determined that PHA does provide an indication of pathogen resistance in certain host species exposed to specific pathogen.