Showing papers on "Mimosine published in 1991"

Mimosine reversibly arrests cell cycle progression at the G1-S phase border.

Abstract: It has previously been demonstrated that the compound mimosine inhibits cell cycle traverse in late G1 phase prior to the onset of DNA synthesis (Hoffman BD, Hanauske-Abel HM, Flint A, Lalande M: Cytometry 12:26-32, 1991; Lalande M: Exp Cell Res 186:332-339, 1990). These results were obtained by using flow cytometric analysis of DNA content to compare the effects of mimosine on cell cycle traverse with those of aphidicolin, an inhibitor of DNA polymerase alpha activity. We have now measured the incorporation of bromodeoxyuridine into lymphoblastoid cells by flow cytometry to determine precisely where the two inhibitors act relative to the initiation of DNA synthesis. It is demonstrated here that mimosine arrests cell cycle progression at the G1-S phase border. The onset of DNA replication occurs within 15 min of releasing the cells from the mimosine block. In contrast, treatment with aphidicolin results in the accumulation of cells in early S phase. These results indicate that mimosine is a suitable compound for affecting the synchronous release of cells from G1 into S phase and for analyzing the biochemical events associated with this cell cycle phase transition.

Mimosine content in the sap of leucaena species resistant and susceptible to Heteropsylla cubana Crawford

Abstract: Resistance of leucaena species and hybrids has been observed during an epidemic of leucaena psyllids (Heteropsylla cubana Crawford). Since leucaena contains mimosine which may confer resistance against the onset of these sap‐feeding insects, mimosine content in the sap of some leucaena accessions was compared. Mimosine concentration found in 7 resistant leucaena accessions with 5 replicates ranged between 3.64 to 12.16% (fresh weight) whilst 6 accessions in the susceptible group ranged between 5.38 to 12.53%. Mean value from the resistant accessions (6.82 + 2.05%) was lower than the susceptible leucaenas (8.60 ± 1.55%), but this difference was not significant (P = 0.01). Since higher mimosine level was not found among the resistant leucaenas, the basis of resistance is not due to the presence of this toxic compound.

The virulence of L. leucocephala for goats in northeastern Mexico

Abstract: When fed 100% Leucaena during a period of 45 days goats with experience in L.-fodder took significantly (P less than 0.05) more dry matter (50.01 g/kg0.75) than those without or only possible experience (44.40 g/kg0.75 and 45.63 g/kg0.75). The uptake of Mimosine from animals with Mimosine experience (1.14 g/kg0.75) has also been significantly higher (P less than 0.05) than from two other groups with non or only possible experience (0.93 g/kg0.75 and 0.92 g/kg0.75). The Serum-Thyroxin level (T4) of the control group (5.12 micrograms/100 ml) and of the group with Leucaena experience (4.65 micrograms/100 ml) has been significantly higher (P less than 0.05) during the entire trial period than that of the two other trial groups (3.9 micrograms/100 ml). Hair-loss, reduced fodder uptake, increased salivation, excitation, ataxia of hind legs, vomit of fodder and uncoordinated chewing of fodder have been observed in animals without or only possible Leucaena experience. Three animals of those died through direct or indirect influence of the poisoning. Swollen buccal papillae, ulceration and necrosis of the oesophagus and haemorrhagic lesions in the reticulum and rumen have been observed in two of the dead animals.