Showing papers on "Mimosine published in 1980"

Stability constants for metal complexation by isomers of mimosine and related compounds

Abstract: Stability constants for the Mg2+, Ca2+, Cu2+ and Zn2+ complexes of two isomers (2) and (3) of the defleecing agent mimosine (1) have been sought from potentiometric titrations in aqueous solution, 0.15 M KNO3, at 37°. For the interpretation of the results, complex formation of the simpler ligands 3-hydroxypyridin-4(1H)-one (4), its 2-oxo isomer (5) and DL-α-amino-β-(6-oxo-1,6-dihydropyridin-2-yl)propanoic acid (6) was studied. The results with ligand (2) are very similar to those with mimosine, for which a computer blood-plasma model indicates metal chelation under physiological conditions. Ligand (3) is a much weaker complexing agent.

Changes in the Matrix Proteins of Wool and Mouse Hair Following the Administration of Depilatory Compounds

Abstract: After sheep were defleeced with mimosine, cyclophosphamide or N-[5-(4-aminophenoxy)pentyl]-phthalimide, the first samples of the new growth of wool differed markedly in composition from the pretreatment samples, there being substantial reductions in the high-tyrosine proteins and increases in the high-sulfur proteins. Similar results were obtained with mice dehaired with mimosine and with sheep treated with low levels of mimosine which resulted in weakened wool rather than depilation. The composition of later samples of the regrowth wool showed progressive changes with time. The high-tyrosine proteins tended to approach the pretreatment levels, although this may take up to 12 weeks to occur, whereas the levels of high-sulfur proteins, after the initial increase, often fell below normal. In experiments involving defleecing with cyclophosphamide, the level of the latter proteins was still below normal after 3 months. The possibility that this altered protein composition of keratin fibres is characteristic of that portion of fibre first produced by a new or regenerating follicle was investigated in sheep and mice. It was found that wool follicles regenerating after plucking, and newly operating follicles in young sheep and mice, also produced wool and hair with a reduced content of high-tyrosine proteins. It is suggested, therefore, that the apparent long-term inhibition of the high-tyrosine proteins may not be the direct consequence of the administration of the chemical but rather be characteristic of normal wool and hair regrowth. Infusion of an amino acid mixture lacking methionine into the abomasum of sheep caused the growth of weak wool but did not suppress the synthesis of the high-tyrosine proteins. This is in contrast with previous findings that treatments which weaken wool also suppress high-tyrosine proteins.

Ipil-ipil (Leucaena leucocephala) leaves as a plant protein source in prawn diets

Abstract: Penaeus monodon juveniles were fed diets containing fish meal, shrimp head meal and ipil-ipil leaves soaked and unsoaked, local and peruvian varieties. Mean weight gain at the end of 8 wk was significantly highest among those given the diet containing commercial ipil-ipil leaves. Gain in length followed the same pattern as mean weight gains. Among the diets containing ipil-ipil leaves there was a direct relationship in the amount of mimosine in the diet and the survival rate, the lower the amount of mimosine (due to soaking) the higher the survival rate. The Results thus indicate the beneficial effect of the addition of commercial ipil-ipil leaves to the diets of prawns, providing the mimosine content is kept low by soaking. A reduce in costs is also obtained, since 1kg of shrimp head meal or fish costs more than 2 or 4 tons, respectively, than that of ipil-ipil foliage.