Growth and mitogenic effects of arylphorin in vivo and in vitro.
In insects, developmental responses are organ- and tissue-specific. In previous studies of insect midgut cells in primary tissue cultures, growth-promoting and differentiation factors were identified from the growth media, hemolymph, and fat body. Recently, it was determined that the mitogenic effect of a Manduca sexta fat body extract on midgut stem cells of Heliothis virescens was due to the presence of monomeric alpha-arylphorin. Here we report that in primary midgut cell cultures, this same arylphorin stimulates stem cell proliferation in the lepidopterans M. sexta and Spodoptera littoralis, and in the beetle Leptinotarsa decemlineata. Studies using S. littoralis cells confirm that the mitogenic effect is due to free alpha-arylphorin subunits. In addition, feeding artificial diets containing arylphorin increased the growth rates of several insect species. When tested against continuous cell lines, including some with midgut and fat body origins, arylphorin had no effect; however, a cell line derived from Lymantria dispar fat body grew more rapidly in medium containing a chymotryptic digest of arylphorin.
Hakim
R S
RS
Department of Anatomy, Howard University, Washington, DC 20059, USA. rhakim@mac.com
Blackburn
M B
MB
Corti
P
P
Gelman
D B
DB
Goodman
C
C
Elsen
K
K
Loeb
M J
MJ
Lynn
D
D
Soin
T
T
Smagghe
G
G
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D001517:Coleoptera / Q000187:drug effects / Q000254:growth & development; D019476:Insect Proteins / Q000494:pharmacology*; D007313:Insecta / Q000187:drug effects / Q000254:growth & development*; D018402:Manduca / Q000187:drug effects / Q000254:growth & development; D008938:Mitosis / Q000187:drug effects; D018411:Spodoptera / Q000187:drug effects / Q000254:growth & development
D019476:Insect Proteins; C041137:storage proteins, Insecta; D001973:Bromodeoxyuridine