Title page for ETD etd-0528103-140647

Document Type thesis

Author Name Levin, Tracy M

Email Address tmlevin at email.com

URN etd-0528103-140647

Title Evidence for the existence of juvenile hormone in the horseshoe crab

Degree MS

Department Biology & Biotechnology

Advisors
Daniel Gibson, Advisor
William Hobey, Committee Member
Alexander DiIorio, Committee Member

Keywords
juvenile hormone
Limulus
horseshoe crab

Date of Presentation/Defense 2003-05-28

Availability unrestricted

Abstract
Lipid-based hormones known as the juvenile hormones (JH) are ubiquitous among the arthropods, but their presence, functions, and sites of production in the horseshoe crab, Limulus polyphemus, remain unknown. Large size and lack of secondary sex characteristics in adult female horseshoe crabs may indicate continuous growth and molting throughout life, which is the outcome of high JH levels in insects and crustaceans. Here a study was undertaken to detect and localize lipid-based hormones in horseshoe crab hemolymph and tissue. Capillary electrophoresis and RP-HPLC analyses indicate the presence of a JH-like compound in subadult horseshoe crab hemolymph. The compound is present only in much lower amounts in the hemolymph of adult male and adult female horseshoe crabs. Identification of this compound was based on its similar retention time to standard JH, co-migration with added JH, and cross-reactivity with a polyclonal antibody to JH III. In addition, immunohistochemistry was used to localize the production site of this compound. Analysis of neural tissue, the assumed site of production, yielded no reactivity with labeled anti-JH III antiserum. In larval animals, however, reactivity was noted in yolk contained within the digestive tract. Since the larvae are lecithotrophic and feeding only on their yolk reserves, JH in the gut may be maternal, deposited in the egg before laying. Based on these results, we conclude that horseshoe crabs produce a lipid-based, JH-like hormone, with functional similarity to JH III in insects (i.e., maintenance of the juvenile form during growth and molting.) This paper is the first substantiation of such a hormone in horseshoe crabs. Our findings suggest that JH will be found in other chelicerates as well.

Files
levin.pdf

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Document Type	thesis
Author Name	Levin, Tracy M
Email Address	tmlevin at email.com
URN	etd-0528103-140647
Title	Evidence for the existence of juvenile hormone in the horseshoe crab
Degree	MS
Department	Biology & Biotechnology
Advisors	Daniel Gibson, Advisor William Hobey, Committee Member Alexander DiIorio, Committee Member
Keywords	juvenile hormone Limulus horseshoe crab
Date of Presentation/Defense	2003-05-28
Availability	unrestricted
Abstract Lipid-based hormones known as the juvenile hormones (JH) are ubiquitous among the arthropods, but their presence, functions, and sites of production in the horseshoe crab, Limulus polyphemus, remain unknown. Large size and lack of secondary sex characteristics in adult female horseshoe crabs may indicate continuous growth and molting throughout life, which is the outcome of high JH levels in insects and crustaceans. Here a study was undertaken to detect and localize lipid-based hormones in horseshoe crab hemolymph and tissue. Capillary electrophoresis and RP-HPLC analyses indicate the presence of a JH-like compound in subadult horseshoe crab hemolymph. The compound is present only in much lower amounts in the hemolymph of adult male and adult female horseshoe crabs. Identification of this compound was based on its similar retention time to standard JH, co-migration with added JH, and cross-reactivity with a polyclonal antibody to JH III. In addition, immunohistochemistry was used to localize the production site of this compound. Analysis of neural tissue, the assumed site of production, yielded no reactivity with labeled anti-JH III antiserum. In larval animals, however, reactivity was noted in yolk contained within the digestive tract. Since the larvae are lecithotrophic and feeding only on their yolk reserves, JH in the gut may be maternal, deposited in the egg before laying. Based on these results, we conclude that horseshoe crabs produce a lipid-based, JH-like hormone, with functional similarity to JH III in insects (i.e., maintenance of the juvenile form during growth and molting.) This paper is the first substantiation of such a hormone in horseshoe crabs. Our findings suggest that JH will be found in other chelicerates as well.
Files	levin.pdf