| Proteus vulgaris: Microbe Unknown
Microbiology November 29, 2004  |
The purpose of the experimental determination of an unknown was to demonstrate the utility of many tests that indicate the metabolic behavior of the unknown microbe. In this experiment, the unknown was determined to be Proteus vulgaris. The bacterium is a gram-negative rod with flagella. It has been shown that its optimal growth temperature was at 37 C (10). P. vulgaris is a chemoheterotroph, which means it uses carbon sources like glucose for energy and carbon (1); as a chemoheterotroph, it ferments glucose but not lactose or mannitol (2). However, because it is a facultative anaerobe, the glucose fermentation only occurs in anaerobic conditions; if placed in non-ideal, aerobic conditions, the microbe will use a variety of organic molecules to survive (8). In order to determine the unknown, several microbial metabolic tests were used. The Gram stain as well as the oxidase, carbohydrate utilization, citrate, indole, and hydrogen sulfide tests were the metabolic tests used. Paper: Proteus vulgaris: Microbe Unknown Flowchart |
| Dictyostelium Differentiation
Freshmen Biology December 5, 2003 Kim Jacques, Laura Keslar, and Eytan Sebag  |
The Dictyostelium begins its life as a single-celled amoeba and eventually develops into a mature fruiting body. It is also known that charcoal's absorption of ammonia attract the Dictyostelium as it develops due to the ammonia gradient that becomes established. The hypothesis is that in a closed container with charcoal, more Dictyostelium will appear closer to the charcoal as time progresses. In fact, this appeared to be true; because at the end of a 7 day period, the Dictyostelium near the charcoal increased from approximately 103 to 275, over 167%, than at the beginning of the experiment. The final average amount of Dictyostelium on the trial plates was 275, approximately 50% higher than the final average amount of dicty on the control plates without charcoal at 184 dicty per control plate. Many trials and a control variable were essential for performing the experiment and arriving at this conclusion.
Dictyostelium Differentiation |
| Superparasitism
Freshmen Biology April 27, 2004 Mia Gatti, Emma Huang, Laura Keslar, Leslie Segura |
The relationship between superparasitism and the rate of successful parasitism has been described as maladaptive. Aphidius ervi are known to singly parasitize Acrythosiphon pisum (the pea aphid), laying only one egg inside the host's body. Although the relationship between symbionts in the aphid and the success of parasitism have been established in previous literature, it is the goal of this study to determine whether or not superparastism was beneficial in the survival of wasp larva in an extremely resistant host. It was expected that superparasitism would help overcome the aphid's natural defenses by injection of more venom and other necessary biological compounds that would help protect the developing egg. In the study, the uninfected 5A lineage of aphids were used as the control whereas the infected T5A lineage was used as the study sample. It was found that no significant differences arose from superparastism and single parasitism of the uninfected aphids; however, there was a significant trend in the T5A lineage indicating that superparasitizing an aphid increased the likelihood that the wasp larvae would develop to adulthood. This indicated that natural and introduced symbionts can only protect the aphids to a certain point.
Superparasitism as a strategy to overcome host defenses |
