Research Description

Overview

At the broadest level, research conducted by my group is directed towards understanding how parasites survive within their hosts. Our long-term goals are focused on finding new ways to interrupt transmission of parasites to and from insect vectors. We are particularly interested in the interactions between the mosquito immune system and malaria parasites.

We also carry out research on problems of special importance to Wisconsin. That research has focused on examination of alternative ways to repel mosquitoes, the use of vitamin B as a systemic repellent, and the ecology and biology of Lyme Disease and anaplasmosis in Wisconsin. Currently, this part of the research program is directed towards investigating West Nile virus.

Our research has been funded by multiple sources, principally NIH, WHO, and the University of Wisconsin (USDA-Hatch).

Current focal areas include:

1) The role of antimicrobial peptides/proteins in mosquito immunity and Plasmodium development.

This new area of research is directed toward investigation of the role of lysozyme in mosquito biology. There are 8 lysozyme genes in Anopheles gambiae, all of which are expressed at various stages and tissues. Several demonstrate structural features that suggest they have novel functions.

We are examining the role of these proteins in relation to bacterial proliferation in the midgut after blood-feeding, larval feeding biology, and parasite/bacterial infections.

Sample publications include:

Paskewitz S.M., Li B.,, and Kajla M. Cloning and molecular characterization of two invertebrate type lysozymes from Anopheles gambiae. Insect Molecular Biology. 17:217-225. 2008.

Waterhouse R.M., Xi Z., Kriventseva E., Meister S., Alvarez K.S., Bartholomay L.C., Barillas-Mury C., Bian G., Blandin S., Christensen B.M., Dong Y., Jiang H., Kanost M., Koutsos A.C., Levashina E.A., Li J., Ligoxygakis P., MacCallum R., Mayhew G.F., Mendes A., Michel K., Osta M., Paskewitz S., Shin S.W., Vlachou D., Wang L., Wei W., Zheng L., Zou Z., Severson D.W., Raikhel A.S., Kafatos F.C., Dimopoulos G., Zdobnov E., and Christophides G.K. Evolutionary dynamics of immune-related genes and pathways in disease vector mosquitoes. Science 316: 1738-1743. 2007.

Li Bin, Calvo E., Marinotti O., James A.A. and Paskewitz S.M. Characterization of the c-type lysozyme gene family in Anopheles gambiae. Gene 360:131-139. 2005.

Lowenberger C.A. , Kamal S., Chiles J., Paskewitz S., Bulet P., Hoffmann J.A., and Christensen B.M. Mosquito-Plasmodium interactions in response to immune activation of the vector. Experimental Parasitology 91:59-69. 1999.

3) Factors controlling melanotic encapsulation of parasites.

Melanotic encapsulation is a process where the pigment melanin is deposited around malaria parasites, filarial parasites, bacteria or Sephadex beads. Melanin formation is also important in egg development and cuticle formation. We are investigating the proteins that are involved in production of this compound. In particular, we focus on a group of enzymes called serine proteases. We have identified a number of serine proteases in Anopheles gambiae and are currently characterizing their activity in relation to melanization. Inhibitors of phenoloxidase are also under investigation. Sample publications include:

Paskewitz S.M., and Andreev O. Silencing the genes for dopa decarboxylase or dopachrome conversion enzyme reduces melanization of foreign targets in Anopheles gambiae. Comparative Biochemistry and Physiology Part B. Biochemistry and Molecular Biology. 150:403-408. 2008.

Patchara Sriwichai, Yupha Rongsriyam, Narissara Jariyapan, Chamnarn Apiwathnasorn, Jetsumon Sattabongkot, and Susan Paskewitz. Cloning of three serine protease genes from the South East Asian malaria vector, Anopheles dirus, and their expression in relation to blood feeding and parasite infection. Developmental and Comparative Immunology. 32:1011-1014. 2008.

BIN LI and SUSAN PASKEWITZ. A role for lysozyme in melanization of Sephadex beads in Anopheles gambiae. Journal of Insect Physiology. 52:936-942. 2006.

SUSAN PASKEWITZ, OLGA ANDREEV and LEI SHI. Gene silencing of serine proteases affects melanization of Sephadex beads in Anopheles gambiae. Insect Biochemistry and Molecular Biology. 36: 701-711. 2006.

SHI, L., LI B., and PASKEWIZ S.M. Cloning and characterization of a putative phenoloxidase inhibitor (POI) from Anopheles gambiae. Insect Molecular Biology. 15:313-320. 2006.

LI B., HUANG Y., and PASKEWITZ S.M. Hen egg white lysozyme as an inhibitor of mushroom tyrosinase. FEBS Letters 250:1877-1882. 2006.

 

3) West Nile virus and integrated mosquito management in southern Wisconsin

 
Mosquito on face

 
Patrick HLC

Gravid trap Patrick

 

1. Compare human landing, CO2-baited light trap, and gravid trap collections of mosquitoes at six sites to determine validity of traps in quantifying relative abundance of human-feeding mosquitoes and to produce temporal profiles of mosquito species composition. Assess these mosquito samples for the presence of WNV.
2. Collect fed mosquitoes and determine the blood meal source by serological and polymerase chain reaction-based methods.
3. Compare circadian feeding rhythms for suspected bridge vectors by collecting humanlanding mosquitoes at different periods of the day.
4. Biological control of Culex in difficult sites using fathead minnows

In addition, undergraduate and graduate students test mosquito control methods and home remedies that are marketed to the general public. These include topical repellents, sonic devices, area repellents (plants and candles), CO2-emitting traps, as well as common lore pertaining to mosquito attraction and control (vitamin B, garlic, bananas). The results of these tests and a summary of other scientific analyses are summarized here: http://www.entomology.wisc.edu/mosquitosite

References

Hughes T.H., Irwin P.M., Kaufman A., Sage H., and Paskewitz S.M. First records of Aedes japonicus japonicus in Wisconsin. Journal of the American Mosquito Control Association. In press.

Irwin P., Arcari C., Hausbeck J., and Paskewitz S.M. The urban wet landscape as mosquito habitat in the upper Midwest. Ecohealth. 5:49-57. 2008.