Date of Award

Spring 2001

Document Type


Degree Name

Master of Science (MS)


Biological Sciences



Committee Director

Daniel E. Sonenshine

Committee Member

Wayne Hynes

Committee Member

Robert E. Ratzlaff

Call Number for Print

Special Collections LD4331.B46 C392 2001


In addition to the soluble response, many invertebrates control bacterial infections by means of phagocytosis or melanotic encapsulation. In some insects, Escherichia coli growth is reported to be inhibited by aggregation/encapsulation. Soluble and phagocytic responses to bacterial challenge have been reported in ticks, but evidence of an aggregation/encapsulation response was reported only for inanimate (araldite) implants. This study was done to determine how ticks control infection by E. coli. Ticks were challenged by direct inoculation of bacteria into the hemocoel cavity. Using plate counts, no viable E. coli were detected I hour post-inoculation. A direct fluorescence assay (DF A) revealed aggregated bacteria at the I-hour time period. Furthermore, DF A showed aggregated bacteria at 6, 24 and 48-hour time periods with associated masses of tissue, presumably of cellular origin, suggesting the events similar to those described as nodulation. These findings suggest that encapsulation/nodulation may be an important component of the resistance in ticks.


In Copyright. URI: This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).