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PubMed2001

Amaranthus palmeri resistance and differential tolerance of Amaranthus palmeri and Amaranthus hybridus to ALS-inhibitor herbicides.

Suspected imazaquin-resistant accessions of Amaranthus palmeri were studied to determine the magnitude of resistance and cross-resistance to acetolactate synthase (ALS)-inhibiting herbicides and compare differential tolerance of A palmeri and Amaranthus hybridus to ALS inhibitors. Five of seven A palmeri accessions were resistant to imazaquin. The most imazaquin-resistant accession, accession 7, also showed 74, 39 and 117 times higher resistance than the susceptible biotype to chlorimuron, diclosulam and pyrithiobac, respectively. Resistance to imazaquin and cross-resistance to other ALS inhibitors in A palmeri was due to a less-sensitive ALS enzyme. A palmeri was 70 times more tolerant to imazaquin than A hybridus. A palmeri was also seven times more tolerant to pyrithiobac than A hybridus. Differences in ALS enzyme sensitivity could not fully account for the high tolerance of A palmeri to imazaquin compared to A hybridus. Both species were equally affected by chlorimuron and diclosulam.

Acetolactate Synthase↗
PubMed1990

Concentrations of long-chain acyl-acyl carrier proteins during fatty acid synthesis by chloroplasts isolated from pea (Pisum sativum), safflower (Carthamus tinctoris), and amaranthus (Amaranthus lividus) leaves.

Fatty acid synthesis from [1-14C]acetate by chloroplasts isolated from peas and amaranthus was linear for at least 15 min, whereas incorporation of the tracer into long-chain acyl-acyl carrier protein (ACP) did not increase after 2-3 min. When reactions were transferred to the dark after 3-5 min, long-chain acyl-ACPs lost about 90% of their radioactivity and total fatty acids retained all of theirs. Half-lives of the long-chain acyl-ACPs were estimated to be 10-15 s. Concentrations of palmitoyl-, stearoyl-, and oleoyl-ACP as indicated by equilibrium labeling during steady-state fatty acid synthesis, ranged from 0.6-1.1, 0.2-0.7, and 0.4-1.6 microM, respectively, for peas and from 1.6-1.9, 1.3-2.6, and 0.6-1.4 microM, respectively, for amaranthus. These values are based on a chloroplast volume of 47 microliters/mg chlorophyll and varied according to the mode of the incubation. A slow increase in activity of the fatty acid synthetase in safflower chloroplasts resulted in long-chain acyl-ACPs continuing to incorporate labeled acetate for 10 min. Upon re-illumination following a dark break, however, both fatty acid synthetase activity and acyl-ACP concentrations increased very rapidly. Palmitoyl-ACP was present at concentrations up to 2.5 microM in safflower chloroplasts, whereas those of stearoyl- and oleoyl-ACPs were in the lower ranges measured for peas. Acyl-ACPs were routinely separated from extracts of chloroplasts that had been synthesising long-chain fatty acids from labeled acetate by a minor modification of the method of Mancha et al. (Anal. Biochem., 1975, 68, 600-608). The results compared favorably with those obtained using alternative analytical methods such as adsorption to filter paper and partition chromatography on silicic acid columns. The acyl-ACP which coprecipitated with ammonium sulfate was not affected by treatments with neutral hydroxylamine or borohydride, whereas that eluted from silicic acid was relatively easily derivatized. A single radioactive polypeptide of Mr 11,500 from pea and amaranthus chloroplasts was revealed by autoradiography of gels from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the silicic acid eluates.

Acetates↗
PubMed2003

Uptake of 134Cs in the shoots of Amaranthus tricolor and Amaranthus cruentus.

Amaranthus tricolor L. and Amaranthus cruentus L. were grown in pots containing 7.5 kg soils artificially contaminated with three levels of 134Cs activity: 5.55 x 10(5) Bq pot-1, 1.11 x 10(6) Bq pot(-)1, and 1.665 x 10(6) Bq pot(-1), respectively. Forty-nine days after sowing and growth, plants were harvested. The plants growing in soils with increasing 134Cs concentrations showed increasing concentration of this radionuclide in shoots. There were significant differences in uptake of 134Cs applied to soils between and within the plant species, depending on the initial 134Cs concentrations. The plant species showed different responses to the addition of (NH4)2SO4 to soils. Biomass production of both species was reduced in pots treated with (NH4)2SO4. (NH4)2SO4 application decreased the uptake of 134Cs by A. tricolor but increased the accumulation of 134Cs by A. cruentus, showing that chemicals with the highest efficiency to enhance the desorption of 134Cs might play an unexpected role in transferring the radionuclide to shoots.

Amaranthus↗
PubMed1998

[Evaluation of the chemical characteristics and physical and rheological properties of the starch isolated from 2 amaranth species (Amaranthus cruentus and Amaranthus hypochondriacus)].

In this study the chemical composition, and the physical and rheological properties of starches isolated from seeds of three experimental varieties of Amaranthus cruentus and Amaranthus hypochondriacus, were evaluated. The starch content of amaranth grains was evaluated by two methods. The starch obtained showed a high purity with protein contents ranging from 0.90 to 0.93; the fat content was higher in A. cruentus starch than in the other two samples. The amylose content was different between the A. cruentus x A. cruentus sample (27.34%) and the other two starches (A. hypochondriacus; 12.47% and A. cruentus; 12.61%). The rheological properties (amylographic and viscosity curves) of starches isolated from A. cruentus y A. hypochondriacus were similar.

Chemical Phenomena↗
PubMed1994

[Chemical and nutritional characterization of amaranthus (Amaranthus cruentus)].

Two samples of Amaranthus cruentus harvested in 1987 (sample A) and 1990 (sample B) were studied. Whole and refined flours were obtained. The whole flours contained 14.6 and 12.6% protein and 6.6 and 7.3 ether extraction, respectively. Both samples contained significant levels of Ca, P, Mg and K. Amaranth oil contained 19% palmitic acid, 3.4% stearic acid, 3.4% stearic acid, 34% oleic acid and 33% linoleic acid. Docosaenoic acid (C22:1) was present at the level of 9%. The ratio of saturated to unsaturated fatty acids was approximately 1:3. The level of crude fiber was 3.7% in the whole flours and 2.4% in the refined ones. Biological protein quality of flours was measured in the rat by the net protein ratio (NPR) method. The NPR values of the four materials tested ranged from 3.04 to 3.20 (NS), as compared with 4.08 for casein. These values are equivalent to 75-78% of the standard protein. Blends of raw wheat flour and whole amaranth flour fed to rats produced a good complementary effect between proteins, as shown by PER test. Wheat flour gave a poor PER value of 0.54. However, this figure increased with every increment of amaranth flour reaching a value of 2.15 for the blend 25:75. The PER for the amaranth diet (0:100) was 1.94 (casein 2.77). As expected, the extrusion process applied to the wheat/amaranth and corn/amaranth mixtures improved the biological quality of the protein. The wheat flour diet (100:0) gave a PER value of 1.64. Mixture 90:10 produced a low non significant increase in the protein quality.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Amplified fragment length polymorphism-based genetic relationships among weedy Amaranthus species.

Weedy Amaranthus species frequently cause economically significant reductions in crop yields. Accurate identification of Amaranthus species is important for efficient weed control, but Amaranthus species can interbreed, which might cause difficulty when identifying hybrid-derived specimens. To determine which of several economically important weedy Amaranthus species are most genetically similar, and thus most likely to produce viable hybrids, we performed amplified fragment length polymorphism (AFLP)-based unweighted pair group method with arithmetic mean (UPGMA) analysis on 8 of these species, with 141 specimens representing 98 accessions. The analysis grouped the specimens into four principal clusters composed of Palmer amaranth (Amaranthus palmeri S. Wats.) and spiny amaranth (Amaranthus spinosus L.); Powell amaranth (Amaranthus powellii S. Wats.), redroot pigweed (Amaranthus retroflexus L.), and smooth pigweed (Amaranthus hybridus L.); waterhemp (Amaranthus tuberculatus (Moq.) Sauer) and sandhills amaranth (Amaranthus arenicola I.M. Johnst.); and tumble pigweed (Amaranthus albus L.). The cluster analysis provided evidence suggesting hybridization among Powell amaranth, redroot pigweed, and smooth pigweed. Further investigations using molecular analysis of the ribosomal internal transcribed spacer region from atypical plants supported this notion. Three species, Palmer amaranth, sandhills amaranth, and waterhemp, are dioecious; nevertheless, the Palmer amaranth and waterhemp-sandhills amaranth clusters were distinct from each other. The Palmer amaranth-spiny amaranth cluster included a cluster of Palmer amaranth and two clusters of spiny amaranth, a monoecious species. Thus the dioecious species Palmer amaranth and waterhemp may not necessarily hybridize with each other more readily than they would to one or more of the monoecious Amaranthus species.

Amaranthus↗
PubMed2002

Extraction and purification of squalene from amaranthus grain.

Grain amaranth has been suggested as an alternative to marine animals as a natural source of squalene. Oil contents, squalene contents, and fatty acid profiles were determined in 11 genotypes of four grain amaranth species. Although the oil contents of grain amaranth were low (from 5.1% in Amaranthus tricolor to 7.7% in Amaranthus cruentus) as compared to other oil-containing grains, high concentrations of squalene were found in total lipids, ranging from 3.6% in Amaranthus hypochondriacus to 6.1% in A. tricolor. The major fatty acids in Amaranthus oil consisted of palmitic acid (19.1-23.4%), oleic acid (18.7-38.9%), and linoleic acid (36.7-55.9%). A high degree of unsaturation was observed in Amaranthus oils, with S/U ratios of 0.26-0.32. A method to isolate and purify the squalene from Amaranthus oil was developed. After the saponification of K112, the squalene content increased from 4.2% in the crude oil to 43.3% in the unsaponifiables by the removal of the saponifiables. The unsaponifiables were fractionated by silica gel column chromatography to get highly purified squalene. The squalene purity in certain fractions was as high as 98%. Combining the fractions rich in squalene gave a 94% squalene concentrate, with a yield of 90%. The structure of squalene in the purified sample was confirmed by comparison of its ultraviolet spectrum with a standard and from its nuclear magnetic resonance spectra.

Amaranthus↗
PubMed2003

Potential of Amaranthus seeds in supplementary feed and its impact on growth in some carps.

Amaranthus seeds were used at three different levels (20%, 35%, 50%) in fish diets under a semi-intensive fish culture system and their impact on the growth of common carp, Cyprinus carpio, and rohu, Labeo rohita, was studied. Growth in terms of body weight gain was maximum in fish fed on diets containing 20% Amaranthus seeds, that replaced rice bran and groundnut oil cake in the feed. Overall, the fish fed on diets containing Amaranthus seeds at different levels showed better growth than the control, because of the good-quality proteins available in Amaranthus seeds. In the two species used, L. rohita showed better growth performance than C. carpio.

Amaranthus↗
PubMed2003

Oil and squalene in amaranthus grain and leaf.

Amaranthus grain of 104 genotypes from 30 species was investigated for oil and squalene contents and fatty acid profiles. The overall average oil content in Amaranthus grain was 5.0%, ranging from 1.9 to 8.7%. Squalene concentration in extracted oils ranged from trace to 7.3%, with an average concentration of 4.2%. The average contents of three major fatty acids in Amaranthus grain were 22.2, 29.1, and 44.6% for palmitic, oleic, and linoleic, respectively. The average fat content in dried mature leaves of 45 Amaranthus genotypes was 1.63%, ranging from 1.08 to 2.18%. The squalene concentration in leaf lipid extracts averaged 0.26%, ranging from trace to 0.77%, which is much lower than that from seeds. The major fatty acids of leaf extracts were linolenic, linoleic, and palmitic. Linolenic ranged from 56.5 to 62.0% of total fatty acids; linoleic, from 15.5 to 24.7%; and palmitic acid, from 13.5 to 15.5%. As for the fatty acid compositions at different growth stages, fatty acid content in leaf lipid was lower in mature leaves than in young leaves. The saturated/unsaturated ratio decreased when the leaf grew to maturity. Principal component analysis (PCA) was carried out on compositional characteristics of grain. The first two components accounted for 70% of the total variance (38.3 and 21.7%, respectively). There was a positive correlation between oil content and squalene yield, and a negative correlations were found between linoleic and either of the other two major fatty acids, palmitic and oleic. The taxonomic relationship among the species was also elucidated by PCA.

Amaranthus↗
PubMed1987

Fatty Acid Specificity and Selectivity of the Chloroplast sn-Glycerol 3-Phosphate Acyltransferase of the Chilling Sensitive Plant, Amaranthus lividus.

Chilling sensitivity of plants is strongly correlated with the presence of high levels of a species of chloroplast phosphatidylglycerol that contains two saturated fatty acids. The most straightforward synthetic pathway for this lipid would require the primary acylation of sn-glycerol 3-phosphate (G3P) with a saturated fatty acid (palmitic acid) rather than with oleic acid, an unsaturated acid. This selective incorporation would differ markedly from the reported properties of the chloroplast G3P acyltransferases of pea and spinach, two chilling resistant plants and thus we have studied the chloroplast G3P acyltransferase of Amaranthus lividus, a chilling sensitive plant. In contrast to our results and those of others (M. Frentzen et al. 1983 Eur J Biochem 129: 629-636 and previous work) with the pea and spinach enzymes, the amaranthus chloroplast G3P acyltranferase did not select oleic acid donors from a mixture of oleic and palmitic acid donors (either coenzyme A or acyl carrier protein thioesters). Instead the fatty acid composition of the synthesized 1-acyl G3P faithfully reflected the composition of the acyl donor mixture. However, the amaranthus enzyme did strongly select against incorporation of stearic acid. The properties of the amaranthus G3P acyltransferase are consistent with this enzyme having the major role in synthesis of the disaturated phosphatidylglycerol species.

Journal Article↗
PubMed2005

In vivo antimalarial activities of extracts from Amaranthus spinosus L. and Boerhaavia erecta L. in mice.

Extracts obtained from two Burkinabe folk medicine plants, spiny amaranth (Amaranthus spinosus L., Amaranthaceae) and erect spiderling (Boerhaavia erecta L., Nyctagynaceae) were screened for antimalarial properties with the aim of testing the validity of their traditional uses. The plant extracts showed significant antimalarial activities in the 4-day suppressive antimalarial assay in mice inoculated with red blood cells parasitized with Plasmodium berghei berghei. We obtained values for ED(50) of 789 and 564 mg/kg for Amaranthus spinosus and Boerhaavia erecta extracts, respectively. Moreover the tested vegetal material showed only low toxicity (1,450 and 2,150 mg/kg as LD(50) for Amaranthus spinosus and Boerhaavia erecta, respectively).

Amaranthus↗
PubMed2002

[Copia-like retrotransposon in Amaranthus].

This study analyzed the characteristics of reverse transcriptase sequences of copia-like retrotransposons in Amaranthus via PCR amplification and sequence approaches. The results are as follows: (1) The reverse transcriptase sequences of copia-like retrotransposons were detected in all 30 Amaranthus accessions studied, indicating that this class of retrotransposons is ubiquitous in Amaranthus; (2) Twenty-eight reverse transcriptases in A. quitensis were cloned and sequenced, showing extensive heterogeneity in base deletion mutation and stop codon mutation; (3) Cluster and alignment analyses of the 28 sequences and other published sequences of the reverse transcriptase from other species (such as rice, tomato and Drosophila) showed that the copia-like retrotransposons in A. quitensis have a close relationship with those in dicot and monocot plants. The evolution of copia-like retrotransposons in A. tricolor, which might be of the same origin as the copia and 1731 in Drosophila, was discussed.

Amaranthus↗
PubMed1994

[Minerals and amino acids in the grains of the recently cultivated "pseudo-cereal" species Amaranthus hypochondriacus].

The mineral elements and the amino acids in seeds of cultivated Amaranthus hypochondriacus were studied. The following conclusions can be made: 1. The contents of minerals in Amaranthus seed are similar to those of wheat and (except of a few elements: P, K) of pea. The habitats of plants, especially the soil conditions effect importantly on minerals. -2. The total amino acid content and mainly the rate of essential amino acids (lysine, arginine etc) are higher than those in seeds of wheat and maize and this fact create the importance of cultivation and utilisation of this plant. The cultivated Amaranthus species have favourable ecological properties (drought resistance, undemanding) too.

Amino Acids↗
PubMed2003

Amino acid sequence, biochemical characterization, and comparative modeling of a nonspecific lipid transfer protein from Amaranthus hypochondriacus.

Plant nonspecific lipid transfer proteins (nsLTPs) are characterized by their ability to bind a broad range of hydrophobic ligands in vitro. Their biological function has not yet been elucidated, but they could play a major role in plant defense to physical and biological stress. An nsLTP was isolated from Amaranthus hypochondriacus seeds and purified by gel filtration and reversed-phase high-performance liquid chromatography techniques. The molecular mass of the protein as determined by mass spectrometry is 9747.29 Da. Data from amino acid sequence, circular dichroism and binding/displacement of a fluorescent lipid revealed that it belongs to the nsLTP1 family. The protein shows the alpha-helical secondary structure typical for plant nsLTPs 1 and shares 40 to 57% sequence identity with nsLTPs 1 from other plant species and 100% identity with an nsLTP1 from Amaranthus caudatus. A model structure of the protein in complex with stearate based on known structures of maize and rice nsLTPs 1 suggests a protein fold complexed with lipids closely related to that of maize nsLTP1.

Amaranthus↗
PubMed2003

Amaranthus paniculatus (Linn.) improves learning after radiation stress.

Brain is highly susceptible to oxidative damage due to its high utilization of oxygen and rather poorly developed antioxidative defense mechanism. Free radicals formation is greatly augmented during ionizing radiation exposure, which causes damage in cerebellum responsible for locomotor activity. Amaranthus paniculatus (Linn.) having high content of beta-carotene (about 15 mg/100g), ascorbic acid, Vitamin C and folate, may prove efficient antioxidants. To evaluate its antioxidative efficacy, healthy Swiss albino mice from an inbred colony were selected and divided into three groups having equal number of male and female in each group. All of these animals were initially trained in Hebb William's Maze, model D(1). After initial training of 10 days, two groups were supplemented with methanolic extract of A. paniculatus (Linn.) at a dose of 600 and 800 mg/kg bw per day, respectively for 15 days. One group without any treatment served as normal. It has been observed that mice, supplemented with extract took lesser time to reach goal than normal (without any treatment). Furthermore after supplementation of Amaranthus, followed by exposure to 9 Gy of gamma radiation by 60Co beam therapy unit, the survived mice took lesser time to reach to their goals than those without plant extract. Control mice (not supplemented with AE extract) showed continuous decline in their learning performance. Mice of Control group died within 12 days after exposure. Irradiated males try to recover from 10th day onwards but they died up to day 12. But in Experimental mice (AE treated), after initial decline in learning ability after exposure, recovery was noticed and not only this 70% of them survived beyond the observation period. Besides male mice showed faster learning ability as compared to females in all groups. After irradiation too, males took lesser time to reach to goals. Learning in all the groups before exposure has been much faster in between 9 and 15 days. After radiation, however it was followed by a sudden spurt and delayed learning response up to 12 days. Recovery was greater in males than females in treated groups. Recovery was greater in males of 600 mg/kg bw per day than other groups. Learning has been almost at the same level from 14th day onward, which indicates that both the dose levels have been found equally effective.

Amaranthus↗
PubMed2005

Amaranthus hybridus can be pollinated frequently by A. tuberculatus under field conditions.

Recent studies have confirmed that weedy Amaranthus species are capable of interspecific hybridization, and such hybridization may foster the evolution of herbicide resistance. However, the extent to which hybridization among these species occurs in nature is unknown. The purpose of this study was to determine the frequency under field conditions at which A. hybridus, a monoecious and predominantly self-pollinated species, would be pollinated by A. tuberculatus, a dioecious species. To do this, parents carrying different alleles at the ALS locus, which encodes a herbicide target site, were used. Male A. tuberculatus parents were homozygous for a dominant herbicide-insensitive allele, while A. hybridus parents were homozygous for a sensitive form. Hybrid progeny therefore could be detected via herbicide selection. Mean hybridization frequencies between 0.4 and 2.3% were obtained, depending on the proximity between parents (P=0.02). The robustness of the hybrid selection assay was verified using a molecular marker and DNA content analyses. Using these techniques, more than 99% of the progeny that survived the herbicide were confirmed to be hybrids. Frequencies obtained in this study were many times higher than the generally expected rate of mutation. Therefore, even minimal fertility in hybrid progeny would support the view that hybridization could play a role in adaptive evolution of weedy Amaranthus species.

Adaptation, Physiological↗
PubMed2006

Effect of coal mine soil contamination on the elemental uptake and distribution in two edible Amaranthus species, A. dubius and A. hybridus.

The impact of coal mine dump contaminated soil on the elemental uptake by two edible plants, namely, Amaranthus dubius (red herbs) and Amaranthus hybridus (green herbs), was studied by investigating their response and ability to tolerate and accumulate varying levels of elements in their roots and shoots. The vegetation was grown on varying amounts of contaminated soil, viz. 0%, 5%, 15%, 25% w/w using coal mine dump soil. The soil was analyzed for soil pH, cation exchange capacity (CEC), soil organic matter (SOM), moisture content, and selected heavy metals. The distribution of six metals, namely, Pb, Cd, Hg, Ni, Mn, and Fe, in roots, stem, and leaves of the plants was determined in two stages of growth after 5 weeks and 10 weeks. All soil and plant samples were microwave digested and subjected to heavy metal analysis using the ICP-OES, GFAAS, and CVAAS. The pH of the coal mine dump contaminated soil decreased with an increase in contamination. Both the SOM and CEC values decreased, which increases the availability of elements, by providing more binding sites in the soil. Relatively, the red herbs had higher elemental concentrations than the green herbs. Both plants recorded high manganese accumulation. No mercury was detected in the soils or plants.

Amaranthus↗
PubMed2005

Heavy metal uptake by two edible Amaranthus herbs grown on soils contaminated with lead, mercury, cadmium, and nickel.

The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively.

Amaranthus↗