Showing papers on "Mimosine published in 2007"

Influence of short-term Leucaena leucocephala feeding on milk yield and its composition, thyroid hormones, enzyme activity, and secretion of mimosine and its metabolites in milk of cattle

Abstract: Four Karan/Friesian crossbred (Holstein×Tharparkar) dairy cows in late lactation (>200 days) were fed a basic diet of green maize and concentrates with an increasing proportion of Leucaena leucocephala (leucaena) leaf meal (LLM). The proportion was gradually increased from 0·25 of the dry matter intake (DMI) in the first week to 0·50 in the second, 0·75 in the third and ad libitum in the fourth week. Mimosine, 3,4-dihydroxy pyridine (3,4-DHP) and 2,3-dihydroxy pyridone (2,3-DHP) levels were determined in milk, serum, urine and faecal samples. On average DMI of leucaena was 0·023–0·025, 0·025–0·027, 0·027–0·028 and 0·022–0·025 of live weight (LW) during the first, second, third and fourth week, respectively. Mimosine, 3,4-DHP and 2,3-DHP appeared in the blood serum during leucaena feeding and continued appearing up to sixth week of experimental feeding even after the withdrawal of leucaena from the 34th day onwards. Similarly, excretion of mimosine, 3,4-DHP and 2,3-DHP were observed even after withdrawal of leucaena from the diet. The feeding of LLM resulted in a reduced level of T3 (Triiodothyronine) and T4 (Thyroxine) within a week of LLM feeding. The level of T3 and T4 improved to normal after withdrawal of LLM from the diet. The serum aspartate transferase (AST) and serum alanine transferase (ALT) activities were within the normal range. Leucaena feeding improved milk yield and composition only up to 3 weeks of feeding. The concentration of mimosine, 3,4-DHP and 2,3-DHP in milk was 0·33, 0·05 and 0·02 that of blood, respectively. The secretion of mimosine, 3,4-DHP and 2,3-DHP in the milk might be a concern for health of the offspring of leucaena-fed animals as well as human beings consuming such milk.

Yield components and nutritive value of Robinia pseudoacacia and Albizia julibrissin in Arkansas, USA

Abstract: Ranchers need alternative livestock feeds when herbaceous forages become limiting in summer. Our objectives were to determine: (1) leaf and stem biomass components, (2) nutritive value [in vitro dry matter digestibility (IVDMD), total nonstructural carbohydrate (TNC), N, and N digestibility] of leaves for animal browse, (3) concentration of the secondary metabolites robinin and mimosine, and (4) in vitro leaf and bark toxicity for black locust (Robinia pseudoacacia L.) and mimosa (Albizia julibrissin Durz.), respectively, pollarded at 50 cm in Arkansas, USA. Black locust exceeded mimosa for every yield component (leaf mass tree−1, leaves shoot−1, shoots tree−1, shoot mass tree−1, stem basal area, and biomass tree−1) except mass leaf−1. Projected yields were 1,900 and 1,600 kg leaves ha−1 for black locust and mimosa, respectively, assuming a population of 12,300 trees ha−1. Mimosa leaves had greater IVDMD, TNC, and N digestibility than black locust. Mimosa leaves exceeded the nutritional N requirements of growing cattle (Bos taurus L.) and goats (Capra hircus L.), but protein supplementation would be needed for growing goats grazing black locust leaves. Tissue concentrations of secondary metabolites robinin and mimosine were below detectable limits in black locust and mimosa, respectively. The extract of black locust bark, but not leaves, was toxic to bioassayed African green monkey (Cercopithecus aethiops L.) cells. Either black locust or mimosa could provide moderate quantities of high quality, rotationally grazed forage for goats during summer months when herbaceous forage may in short supply.

Phytotoxicity of mimosine and albizziine on seed germination and seedling growth of crops and weeds

Abstract: Mimosine and albizziine are non-protein amino acids produced by certain legume species that possess allelopathic activity. Although these allelochemicals have exhibited phytotoxicity in some bioassays, all test plants were not affected. We tested these compounds at various concentrations (10-'to l0'' M) for allelopathic effects on seed germination, growth, and greening of weeds and crops: hemp sesbania (Sesbani"a exaltata) and sicklepod (Senna obtusifulia) and wheat (Triticum aestivum). We also examined in vitro effects of these chemicals on the enzymatic activity of cysteine synthase from sicklepod tissue. Mimosine at 10-'M reduced germination (by - 4OVo) in both wheat and sicklepod. The greatest growth inhibition occurred, when these compounds were supplied via seed imbibition, but some inhibition also was noted in root feeding and sprays of the chemicals on seedtngs. Mimosine and albizziine inhibited chlorophyll development in hemp sesbania and sicklepod cotyledons at all concentrations tested. Chlorophyll inhibition ranged from 25 to 40 Eo for albizziine and from 20 to97%o for mimosine. Both compounds caused a small inhibition (l0Vo) of sicklepod cysteine synthase activity. Generally mimosine was the more phytotoxic compound.

Reversed-Phase High-Performance Thin-Layer Chromatographic Quantification of Mimosine from Whole Plant of Mimosa pudica Linn.

Abstract: A sensitive, simple, and reliable reversed-phase HPTLC method has been established for quantification of mimosine in Mimosa pudica Linn. whole plant powder. The plant powder was first extracted with methanol. The residue was then extracted with water and the aqueous extract was used for quantification. Chromatography was performed on silica gel RP-18 F254s plates with ethyl acetate-glacial acetic acid-water, 6 + 1 + 1.7 ( v/v ), as mobile phase. Quantification was achieved by densitometric scanning at λ max = 282 nm in reflectance-absorbance mode. The response to mimosine was a linear function of concentration over the range 30 to 100 μg mL −1 in the extract. The amount of mimosine in M. pudica was found to be 20 mg g −1 whole plant powder. The method was validated for linearity, precision, accuracy, and robustness.

Substitution of plant protein for fish meal in the diet of laying ducks

Abstract: Fish meal is a good source of protein feed that can be used to get a high production yield even though it has a comparatively higher price. Plant protein has been found to substitute for fish meal without any adverse effect on production as well as helping to reduce feed cost. Moreover, it is not necessary for a level more than 5% fish meal in the diet of laying ducks. One type of plant protein is soybean meal, considered one of the most valuable sources of vegetable protein and whose amino acid composition is comparable to that of milk protein. In a soybean meal, the first limiting amino acid is methionine. Soybean meal can substitute for fish meal in laying ducks’ diet but supplementation of methionine and lysine is recommended. Since sesame meal is rich in methionine and agrinine, 50% of soybean meal can be replaced by sesame meal without adverse effects. Leucaena leaf meal is also a valuable source of protein (26%) and carotenoids but it also has a toxic amino acid (mimosine). However, soaking leucaena leaf meal in water can remove the toxic amino acid and can be used, together with added methionine and lysine, as 10% of the diet for laying ducks.

Beta-carotene, mimosine and quality of leucaena silage kept at different duration

Abstract: Leucaena leucocephala leaves (LL) were ensiled by mixing with 20% rice bran and 20% water (fresh LL basis). The material was kept for 21, 51, 81 and 111 days in vacuumed double layer plastic bags, each containing 26 kg. Five bags were randomly taken at each interval for quality evaluation by organoleptic test as well as by organic acid and chemical analysis. It was found that the ensiling period did not have much influence on most of the chemical compositions. All samples of leucaena leaf silage (LLS) had pH of 4.4-4.5 and 35.22-35.65% DM (dry matter). The compositions on DM basis were 21.49-22.29% CP (crude protein), 7.76-8.22% EE (ether extract), 31.18-33.68% NDF (neutral detergent fiber), 2.0-2.9% acetate and 6.9-9.7% lactate (DM basis). DM loss was 10.35-12.32% which was in the normal range for good quality silage. The most interesting points were the increment of βcarotene after ensiling from 88.50 to 99.92-120.25 mg/kg DM while mimosine content decreased over 90% (from 1.79 to 0.12-0.16% of DM) which were superior to a drying method. It indicated that LLS is a good alternative for preserving LL and for reduction of mimosine.

The pydA–pydB fusion gene produces an active dioxygenase–hydrolase that degrades 3-hydroxy-4-pyridone, an intermediate of mimosine metabolism

Abstract: The objective of this research was to construct a pydA–pydB hybrid gene that encodes a functional dioxygenase–hydrolase (PydA–PydB) fusion protein for degradation of 3-hydroxy-4-pyridone (HP). HP is an intermediate in both synthesis and degradation of mimosine, a toxic amino acid produced by the tree legume Leucaena leucocephala. Computer-generated models of the fusion proteins suggested that joining of PydA and PydB with 0, 3, or 7 glycine residues as a linker should produce a functional PydA–PydB fusion protein. Accordingly, three hybrid genes, G0, G3, and G7, were constructed in which pydA and pydB were connected with 0, 9, and 21 nucleotides, respectively, encoding the glycine residues of the linker region. When these hybrid genes were expressed in Rhizobium and Escherichia coli, only one of them, G3, produced a functional PydA–PydB fusion protein, having both the dioxygenase and hydrolase activities. The G3 hybrid gene could complement both pydA and pydB mutants of Rhizobium, and E. coli lysate containing the overexpressed G3 protein was able to degrade HP. This hybrid gene may be useful for developing mimosine-free L. leucocephala plants in the future.

Mimosine Mitigates Oxidative Stress in Selenium Deficient Seedlings of Vigna radiata-Part I: Restoration of Mitochondrial Function

Abstract: Mimosine, a non-protein plant amino acid found in Mimosa pudica and certain species of Leucaena, was beneficial for the growth of seedlings of Vigna radiata germinated under selenium-deficient stressed condition (−Se stressed) despite the recognized toxicity of the allelochemical. Exposure of mimosine at 0.1 mM (Mim-0.1) promoted the growth of the seedlings and significantly enhanced mitochondrial functional efficiency. Growth-related parameters including root and shoot lengths and dry weight were increased by 44–58% in the Mim-0.1 group compared to that of the −Se-stressed group. Oxygen uptake by mitochondria of Mim-0.1 group, studied with different substrates, revealed enhanced State 3 respiratory rates with regulated State 4 rates, resulting in high respiratory control ratio (RCR) of 3.4 to 3.9 indicative of a high degree of oxidative coupling. Specific activities of mitochondrial electron transport enzymes, nicotinamide adenine dinucleotide (reduced form) (NADH)–cytochrome (cyt) c oxidoreductase, succinate dehydrogenase, and cyt c oxidase in the Mim-0.1 group were enhanced by 53% to threefold over those of the Se-stressed group. Marked decreases in the extent of mitochondrial lipid peroxidation ensued upon mimosine exposure, indicative of its antioxidant function. Mitochondrial 45Ca2+ uptake was notably augmented twofold in the Mim-0.1 group, compared to the Se-stressed group. Detailed kinetic analyses of Ca2+ uptake revealed positive cooperative interactions in both −Se-stressed group and Mim-0.1 groups with Hill coefficient (nH) values of 1.7 and 2, respectively. The present study establishes the beneficial effects of mimosine exposure at 0.1 mM on the growth and mitochondrial function of the seedlings grown under selenium-deficient stressed condition and a significant physiological role can be ascribed to mimosine.

Effect ofensiling Mimosa invisa Mart. on the expression of mimosine toxicity symptoms in animals

Abstract: The study was conducted to observe the toxic effects ofmimosine on the weight ofrabbits and their internal organs. Also the safe level of admixture ofM invisa with fodder grass in. the preparation of silage was assessed. M invisa and Hybrid Napier mixed in different proportions ranging from 25 to 90% were ensiled for 60 days and feeding trial (25 days) was conducted on rabbits, substituting the ensiled material for green grass in the routine diet. Rapid weight reduction, alopecia and sluggishness were the effects of mimosine toxicity. Histopathological studies revealed that mimosine is mainly hepatotoxic and nephrotoxic. The studies proved that admixture of pastures with M invisa up to 50% was safe for feeding after cutting and ensiling for 60 days.

Mimosine mitigates oxidative stress in selenium deficient seedlings of Vigna radiata. Part II: mitochondrial uptake of 75selenium and mimosine.

Abstract: During the growth of selenium (Se)-deficient seedlings of Vigna radiata, exposure to mimosine [2-amino-3-(3-hydroxy-4-oxo-1H-pyridin-1-yl)-propanoic acid], a nonprotein plant amino acid, effectively mitigated stress at 0.1 mM, as reflected in enhancement of growth and efficiency of mitochondrial functions. Since the changes in the seedlings elicited by exposure to mimosine were similar to those effected by Se at an optimal exposure level of 0.75 ppm (Sreekala et al., Biol Trace Elem Res 70:193-207, 1999), the uptake of Se and that of mimosine itself was individually studied in the respiring mitochondria of Se-deficient seedlings (-Se-stressed group) in comparison with those exposed to mimosine during growth at 0.1 mM (Mim 0.1 group). In both groups, the mitochondrial uptake of (75)Se at 10 microM added Na(2)(75)SeO(3), increased linearly up to 2 min, attaining steady-state levels thereafter. Uptake levels were 2.3-fold higher in the Mim 0.1 group than in the -Se-stressed group. Double-reciprocal plots of mitochondrial (75)Se uptake against 2-20 microM Na(2)(75)SeO(3) in the medium were nonlinear and negative cooperative effects during the uptake were confirmed by Scatchard plots, whereas Hill coefficients were 0.8 and 0.85 for the two groups. Mitochondrial uptake of mimosine, at added levels of 25 or 50 microM, increased linearly up to 1 min and decelerated thereafter. Initial uptake levels of mimosine at 1 min were higher by 6.5-fold at 25 microM and 4-fold at 50 microM in the Mim 0.1 group than those in the -Se-stressed group. Initial uptake levels with added mimosine up to 50 or 100 microM yielded nonlinear double-reciprocal plots; and kinetic analyses at 5 to 50 microM revealed the prevalence of positive cooperativity in the -Se-stressed group and negative cooperativity in the Mim 0.1 group. Involvement of active thiol groups in the uptake of both Se and mimosine were indicated by inhibition studies. Evidence presented for mimosine mediated increase in mitochondrial Se uptake and cooperative interactions thereof underscores the metabolic significance of mimosine.