Paul J. Linser Laboratory

Paul J. Linser
Professor of Anatomy and Cell Biology, Entomology and Biology

Developmental and Molecular Biology of Disease Vector Arthropods

The Whitney Laboratory is situated on a narrow barrier island on the northeast coast of Florida, adjacent to Marineland. The island habitat is replete with many aquatic organisms in the adjacent oceanic and intracoastal/estuarine environments. Among the local “swimmers” are species of larval insects that use the salt marsh and its tributaries as breeding grounds. Mosquito larvae are prominent in the shallows of the estuary and its many creeks and fresh water feeders. Mosquitoes have been a concern for humanity for our entire existence, producing a tremendous nuisance and impediment to comfortable living. Beyond the nuisance and comfort perspective, which is quite important in coastal Florida environments, mosquitoes are the number one threat to human health worldwide according to the World Health Organization (WHO). Mosquitoes vector (i.e. transmit) numerous viral and parasitic diseases and are responsible for millions of deaths per year. Malaria alone kills one to two million people per year worldwide. This laboratory works on the fundamental cell and molecular biology of mosquitoes with an emphasis on the aquatic life phase, that is the larvae.

Mosquito larvae, as aquatic organisms, live in a varied and often hostile environment. The mechanism for acquiring nutrients for growth and metamorphosis involves many details. We work specifically on the digestive strategy of mosquito larvae. Larval insects are at the simplest level stomachs with an exoskeleton as their fundamental purpose is to eat enough to fuel the production of a reproductive adult. Mosquito larva have numerous specific digestive attributes that present interesting questions in sciences as well as potential targets for novel control strategies. Our laboratory focuses on the relatively novel quality of larval digestion that is based on an internal pH of the anterior half of the stomach that is extremely basic (pH around 10.5). This is one of the highest pH extremes found in biology. Understanding how the larval gut generates, maintains and functions with this high luminal pH is part of our research direction.

We utilize the tools of molecular biology, cell and tissue physiology and advanced imaging technology to identify and characterize major gene products in the larval mosquito gut function. From comprehensive transcriptomic analyses to cloning specific messenger RNAs to producing immunological probes for the proteins coded by those genes, we strive to build a holistic picture of how specific gene products and their tissue and cellular localization contribute to the functions of the gut and other interactive tissues and cells. Among the4 key players in the alkaline gut of mosquito larvae is a family of genes who produce enzymes of the carbonic anhydrase family. These enzymes are intimately involved in pH regulation as they interconvert carbon dioxide (the major end product of metabolism) and ions such as bicarbonate and carbonate. It is the carbonate anion aligned with a strong cation such as potassium that actually buffers the pH at levels as high as 10.5.

Current Projects

To date we have characterized 8 of the 12 carbonic anhydrases encoded in the mosquito (Anopheles gambiae) genome. Comprehensive gene expression profiling (i.e. DNA micro array analyses) has also been generated which provides the "big picture" of gene expression in relation to homeostasis in the various cell types of the larval gut. New emphases that have emerged from the big picture analyses included a focus on gut function in mediating innate immunity, the role of the salivary glands in gut function and homeostatic ion balance as a function of the activity of the hindgut (rectum) of larvae.

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Personnel

Paul J. Linser, Professor
Tatiana P. Moroz, Laboratory Technician
Leslie A. vanEkeris, Laboratory Technician

Selected Publications

Okech, B.A., Boudko, D.Y., Linser,P.J. and Harvey, W.R. Cationic (2008) Pathway of pH regulation in larvae of Anopheles gambiae. J. Exptl. Biol. 211: 957-968.

Neira, M., Corena, M.D.P., Linser, P.J. A microarray-based analysis of transcriptional compartmentalization in the alimentary canal of Anopheles gambiae (diptera: culicidae) larvae (2008) J. Insect. Mol. Biol. 17(1): 61-72.

Smith, K.E., vanEkeris, L.A., Okech, B.A., Harvey, W.R. and Linser, P.J. (2008) Larval anopheline mosquito recta exhibit a dramatic change in localization patterns of ion transport proteins in response to shifting salinity: a comparison between anopheline and culicine larvae. J. Exptl. Biol. 211: 3067-76.

Smith, K.E., VanEkeris, L.A., and Linser, P.J. (2007) Cloning and characterization of AgCA9, a novel α-carbonic anhydrase from Anopheles gambiae Giles sensu stricto larvae. J. Exptl. Biol. 210: 3919-30.

Linser, P.J., Boudko, D.Y., Corena, M.D.P., Harvey, W.R. and Seron, T.J. (2007) The molecular genetics of larval mosquito biology. J. Am. Mosq. Control Assoc 23(2 suppl.) 283-93.

Rheault, M.R., Okech, B.A., Keen, S.B.W., Miller, M.M., Meleshkevitch, E.A., Linser, P.J., Boudko, D.Y., and Harvey, W.R. (2007) Molecular cloning, phylogeny and localization of AgNHA1 the first Na+/H+ antiporter (NHA) from a metazoan, Anopheles gambiae. J. Exptl. Biol. 210: 3848-61.

Corena M.D.P., Vanden Hurk, P., Zhong, H., Brock, C., Mowery, R., Johnson, J.V. and Linser, P.J. (2006) Degradation and effects of the potential mosquito larvicides methazolamide and acetazolamide in sheepshead minnow (Cyprinodon variegatus) Ecotoxicology and Environmental Safety 64: 369-376.

Fisher, S.Z., Tariku, I., Case, N.M., Tu, C., Seron, T., Silverman, D.N., Linser, P.J., and McKenna, R. (2006) Expression, purification, kinetic, and structural characterization of an alpha-class carbonic anhydrase from Aedes aegypti (AaCA1). Biochem. Biophys. Acta 1764: 1413-9.

Corena, M.D.P., vanEkeris, L., Salazar, M.I., Bowers, D., Fiedler, M.M., Silverman, D., Tu, C., and Linser, P.J. (2005) Carbonic anhydrase in the adult mosquito midgut. J. Exptl. Biol. 208: 3263-3273.

Ochrietor, J.D., Clamp, M.F., Moroz, T.P., Grubb, J.H., Shah, G.N., Waheed, A., Sly,W.S. and Linser, P.J. (2005) Carbonic anhydrase-XIV identified as the membrane CA in mouse retina: Strong expression in Müller cells and RPE. Exp. Eye Res. 81: 492-500.46)

Seron, T.J., Hill, J. and Linser, P.J. (2004) A GPI-linked carbonic anhydrase expressed in the larval mosquito midgut. J. Exptl. Biol. 207: 4559-4572.