Microbiology Student Presentations: Wellesley College

Student Research

Students get many chances to do independent research in Microbiology. These are some presentations in PowerPoint, done by the students of the Spring of '04 class, after they carried out library research on a particular infectious disease. Your computer should open them in a new window in your browser, so you need not have PowerPoint on your computer to view these presentations. When you are done viewing the presentation, simply close that window.

Laboratory experiments and research are also carried out in Bisc 209. Below are two transmission electron micrograph images of bacteria isolated from students' skin:

A number of students choose to spend summer and or wintersession doing laboratory research. Experiments are now underway to determine the relationship of heavy metal resistance to antibiotic resistance and to identify some 41 bacterial isolates using sequence analysis of their 16S ribosomal RNA genes. Below are bacteria isolated from the contaminated soils of the PaintShop Pond cleanup on Wellesley's campus:


Gram negative cocci in filament	Gram positive rods	Gram positive rods with spores


Electron Micrographs -- two types of bacteria isolated from the Paintshop Pond area before remediation.

Other areas of continuing research at Professor Allen's Microbiology Lab: - - - - - - - - - - - - - - - - - - - - -

We study the effects of stressful environments on cyanobacterial cells. In particular, we are currently studying the effect of nitrogen depletion and repletion on two nitrogen storage molecules, cyanophycin and phycocyanin using NMR spectroscopy. The effect of these conditions on the enzyme nitrate reductase is also being determined. Acid stress is being studied using proteomics, growth and pH analysis, and experiments to determine how cells increase the pH of their medium and whether an antiporter is involved.

An electron micrograph of a uni-
cellular cyanobacterium showing
cyanophycin, a nitrogen storage
compound.

Using fluorescence microscopy to identify live (red) and dead (green) cells
of cyanobacteria as pigments in the cells naturally fluoresce red.


Broken cell extracts showing differences in cyanobacterial pigmentation during nitrogen starvation and repletion. The left, yellow, extract is from nitrogen starved cells and only chlorophyll a is seen; no blue phycocyanin is visible in the extract. Tubes 2 and 3 show more phycocyanin that forms as the cells are repleted with nitrogen.	Whole cells photographed during nitrogen starvation (left), exponential phase (center) and stationary phase (right).

Microbiology Lab group, summer 2004.

Devyani Parameshwar '06
Maintained by: Mary Allen
Date Created: July 6, 2004
Last Modified: July 31, 2004
Expires: Fall 2005