Year

2012

Season

Fall

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Dr. Gregory Ahearn

Second Advisor

Dr. Jim Gelsleichter

Third Advisor

Dr. John Hatle

Department Chair

Dr. Dan Moon

College Dean

Dr. Barbara Hetrick

Abstract

Purified brush border membrane vesicles (BBMV) were isolated to characterize primary cellular transport mechanisms for white shrimp. The ultimate goal is to determine the effective components of a shrimp’s diet, thereby enhancing growth, as well as nutrient content. Juvenile shrimp are dependent on plant material as a food source. Potassium is a key component of plants, thus it may play a role in nutrient transport. In addition, divalent metals have been shown to act as co-transporters in several other organisms, thus they may serve as a transport mechanism for shrimp.

Fresh, live, white or brown shrimp were obtained, and from them 15-30 hepatopancreases were dissected to prepare the BBMV. Methods for preparing BBMV were based on the Mg2+ precipitation technique developed by Kessler et al., (1978) and Biber et al. (1981) for mammalian eipithelia and applied to crustaceans.

The results suggest that there is a sodium/potassium-dependent glucose transport system that resembles the SGLT1 system of vertebrates, except the shrimp transporter can accept both sodium and potassium as cofactors, while the vertebrate system is restricted to sodium stimulation. Potassium showed strong stimulation of L-histidine uptake by shrimp BBMV, suggesting that a crustacean isoform of the insect potassium-dependent carrier protein (KAAT1) might be present in shrimp, and contribute to amino acid uptake.

Amino acids also appear to form bis-complexes with divalent metals, that are transported by an analog of the dipeptide transporter (PEPT1). The metals appear to be accommodated, with varying affinities. PEPT1 has been described as a very non-specific carrier process because it transports such a wide range of di- and tripeptide combinations.

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