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Title: THE ROLE OF STEM CELLS IN MIDGUT GROWTH AND REGENERATION

Author
item HAKIM, RAZIEL - HOWARD UNIVERSITY
item BALDWIN, KATE - HOWARD UNIVERISTY
item LOEB, MARCIA

Submitted to: In Vitro Cellular And Developmental Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Heliothis virescens, the tobacco budworm, is a serious agricultural pest, destroying cotton and a number of vegetable crops every year. It is becoming increasingly resistant to chemical and biological insecticides, making it imperative to discover other ways to control it. All of the food and toxins that are eaten pass through its midgut and are transmitted to the rest of the organism. Therefore, it is important to understand the physiology of the midgut in order to find some way of disrupting this organ to prevent feeding and to destroy the pest. The stem cells of the midgut are precursors to all of the other cells of the midgut. They multiply when the animal is changing into larger stages to allow the midgut to grow to fit the newly molted caterpillar, and when the gut is injured in order to repair it. This article consolidates our present knowledge of the midgut cells of caterpillars, particularly of H. virescens. It will be useful to scientists who study midgut physiology, and will allow them to focus on the means by which midgut cells divide and change into the more mature cells of the gut.

Technical Abstract: Manduca sexta and Heliothis virescens midguts consist of a pseudostratified epithelium surrounded by striated muscle and tracheae. This epithelium contains goblet, columnar and basal stem cells. The stem cells are critically important in that they are capable of massive proliferation and differentiation. This growth results in a 4x enlargement of the midgut at teach larval molt. The stem cells are also responsible for limited cell replacement during repair. While the characteristics of the stem cell population vary over the course of an instar, stem cells collected early in an instar and those collected late can start in vitro cultures. Cultures of larval, stem, goblet and columnar cells survive in vitro for several months through proliferation and differentiation of the stem cells. One of the 2 polypeptide differentiation factors which have been identified and characterized from the culture medium has now been shown to be present in midgut in vivo. Thus, the ability to examine lepidopteran midgut stem cell growth in vitro and in vivo is proving effective in determining the basic features of stem cell action and regulation.