Linked Life Data

15890180

Source:http://linkedlifedata.com/resource/pubmed/id/15890180

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-5-13
pubmed:abstractText
Adult male crayfish Procambarus clarkii exist in two morphotypes. They continue to molt as adults, switching between Form Is and Form IIs. Form Is are primary reproductive types, with large chelae and spines on the ischiopodites of the third and fourth pair of walking legs. Form IIs are non-reproductive types with smaller chelae and no spines on the ischiopodites. We investigated the hormonal control of these transitions in two ways, by eyestalk ablation and by methyl farnesoate (MF) treatments. Eyestalk ablation accelerates molting and increases MF levels in the blood. MF is a hormone that regulates both reproduction and morphogenesis. MF concentrations were determined in two ways. The hemolymph samples were extracted first, then purified, using normal phase HPLC. The fractions containing MF were collected and analyzed for MF concentration, utilizing both internal and external standards by GC/MS. The other hemolymph samples were analyzed from individual animals by HPLC. The concentrations of ecdysteroids were determined by radioimmunoassay. In the control animals, 4 out of 4 untreated Form I males molted into Form II, while 6 out of 7 Form IIs molted into Form Is. Eight of 8 ablated Form Is molted into Form IIs as expected, while 5 of 5 ablated Form IIs molted into Form IIs, instead of Form Is. MF treatment of intact animals resulted in 6 of 7 Form Is becoming Form IIs and 5 of 6 Form IIs becoming Form IIs. These results were highly significant in comparison of Form I and IIs in each treatment (eyestalk intact, eyestalk ablated and eyestalk intact with MF) by a chi square analysis, P = 0.006, P < 0.0005, and P = 0.013, respectively. MF premolt blood levels suggested that Form IIs were produced in the presence of 1.3 ng/ml MF, while Form Is result from MF levels less than 0.5 ng/ml. Since both eyestalk ablation and MF treatment resulted in the failure of Form IIs becoming Form Is, it was concluded that the control of morphogenesis of primary reproductives (Form Is) depends on a low level of MF prior to the molt, while Form IIs are formed in the presence of increased levels of MF.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-1910
pubmed:author
pubmed:issnType
Print
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
379-84
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Methyl farnesoate controls adult male morphogenesis in the crayfish, Procambarus clarkii.
pubmed:affiliation
Department of Molecular and Cell Biology, University of Connecticut, Storrs, 06269-3125, USA. hans.laufer@uconn.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't