Biol. Bull. Sign up for etocs!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lovett, D. L.
Right arrow Articles by Felder, D. L.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Lovett, D. L.
Right arrow Articles by Felder, D. L.

The Biological Bulletin, Vol 178, Issue 2 160-174, Copyright © 1990 by Marine Biological Laboratory

PHYSIOLOGY

Ontogenetic Changes in Enzyme Distribution and Midgut Function in Developmental Stages of Penaeus setiferus (Crustacea, Decapoda, Penaeidae)

D. L. Lovett and D. L. Felder
Department of Biology and Center for Crustacean Research, University of Southwestern Louisiana, Lafayette, Louisiana 70504

Ultrastructure and histochemical distribution of enzymes were examined in the midgut of larval and postlarval stages of Penaeus setiferus. Acid phosphatase and esterase activities were present in all gut tissues at all stages. Protease activity was present in the anterior and lateral midgut caeca, as well as in the anterior portion of the midgut trunk (MGT) of larvae and early postlarvae (PL1-PL4). Amylase activity could not be detected histochemically in larvae or early postlarvae, even though it was detected in assays of whole-animal homogenates. In later postlarvae, both protease and amylase activities were present in the hepatopancreas and anterior MGT, but were absent from the anterior midgut diverticulum. In larvae, alkaline phosphatase activity is present throughout the midgut, suggesting that absorption is widespread. In juveniles, activity is restricted to the hepatopancreas and regions of the MGT within the cephalothorax. The abdominal MGT (or "intestine") is no longer absorptive by the time the hepatopancreas has attained its adult form. Although epithelial cells of the MGT synthesize protein and produce electron-dense secretory vesicles, they are substantially different in ultrastructure from those cells in the hepatopancreas responsible for digestive enzyme synthesis and secretion. Epithelial cells of the larval anterior and lateral midgut caeca are structurally and functionally similar to cells of the postlarval hepatopancreas. However, the lateral midgut caeca retain these features as they transform into the hepatopancreas, while the anterior midgut caeca lose these functions as they degenerate into the anterior diverticulum and change in ultrastructure during early postlarval development. The anterior and posterior midgut diverticula of postlarvae are similar ultrastructurally even though they differ in ontogenetic history.


This article has been cited by other articles:


Home page
 Biol. Bull.Home page
G. G. Martin, R. Simcox, A. Nguyen, and A. Chilingaryan
Peritrophic Membrane of the Penaeid Shrimp Sicyonia ingentis: Structure, Formation, and Permeability
Biol. Bull., December 1, 2006; 211(3): 275 - 285.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Bull.Home page
A. Walker, S. Ando, and R. F. Lee
Synthesis of a High-Density Lipoprotein in the Developing Blue Crab (Callinectes sapidus)
Biol. Bull., February 1, 2003; 204(1): 50 - 56.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1990 by the Marine Biological Laboratory.