The duration of phases of the cell cycle are measured in five species and one hybrid of the genus Crepis (Compositae), after pulse labeling with tritiated thymidine. The results indicate significant variations in the duration of post-synthetic interphase (G(2)), which affords a possible explanation for the abnormal chromosome morphology first described in Crepis hybrids as neutral amphiplasty.

BACKGROUND Crepis lacera is a plant from the Asteraceae family that is common in the Mediterranean region. Farmers believe that this plant may be deadly to small ruminants in areas of southern Italy. However, scientific evidence is lacking, and no proof exists that C. lacera is toxic to ruminants. Necropsies conducted on four sheep revealed lesions in their livers and kidneys. RESULTS In the ...

From the roots of Crepis conyzifolia, two new and two known guaianolides were isolated together with three known phenylpropanoids. Structures of the new compounds were established as 8beta-hydroxy-4beta, 15-dihydrozaluzanin C and 4beta, 15, 11beta, 13-tetrahydrozaluzanin C-3-O-beta-glucopyranoside by spectral methods. The identity of 8-epiisolippidiol and dentalactone was also discussed.

In contrast to the huge variety of sesquiterpene lactones reported, only a limited number of flavonoids and phenolic acids are known from the genus Crepis. Compounds detected in the course of this investigation encompass flavonoids luteolin, luteolin 7-O-glucoside, luteolin 7-O-gentiobioside, luteolin 7-Oglucuronide, and luteolin 4’-O-glucoside and caffeic acid derivatives chlorogenic acid, 3,5...

The seed oil of Crepis eonyzaefolia (Gouan) Daile Torre contains previously unidentified (± )-eis-12,13epoxyoctadeca-trans-6-cis-9-dienoic (14 and eis-12,13-epoxyoctadeca-cis-6-cis-9-dienoic (2 ~{) acids and the more common vernolic [( ±)-12,13-epoxyoctadec-cis-9-enoic] (32 %) acid.

Dispensable, supernumerary (B) chromosomes are found in diverse eukaryotic species. The origin and genetic consequences of B chromosomes have been the subjects of speculation for more than a century. Until now, there has been no molecular evidence that B chromosome DNA is transcribed and there is no unequivocal evidence as to their origin. B chromosomes are considered to be genetically inert al...

We have characterized three CoA-independent types of enzyme, phospholipases, phospholipid:diacylglycerol acyltransferases (PDATs) and cholinephosphotransferases, responsible for the removal of unusual fatty acids from phosphatidylcholine (PC) in microsomal preparations from developing oil seeds. The metabolism of sn-2-[(14)C]acyl-PC was monitored in microsomal preparations from various oilseeds...

Analyses of DNA from tumorous and non tumorous cultures of Crepis capillaris by analytical equilibrium centrifugation in a neutral CsCl gradient revealed significant differences in regard to the content of a heavy component satellite, which was more highly represented in tumorous cultures. DNA of plant leaves showed a unimodal distribution of molecules. The choice of suitable controls served to...

A population of Crepis pannonica, growing in the Hosrov reserve in Armenia, at the southem limit ofthe species ' area, has been investigated over a period ofmore than 20 years. An extraordinary chromosomal polymorphism has been detected by the study of root tip mitoses ofseedlings. 40 different chromosome complement variants were found, including a full range of aneuploids, B-chromosomes, struc...