), arginine, and the arginine precursor, citrulline ( Hong et al., 2015 ; Kaore and Kaore, 2014 ; Wang et al., 2014 ). Lycopene is a red-pigmented carotenoid with powerful antioxidant properties that serves as an intermediate for the biosynthesis of other
Todd C. Wehner, Rachel P. Naegele, and Penelope Perkins-Veazie
Jordan L. Hartman, Penelope Perkins-Veazie, and Todd C. Wehner
several pharmacokinetic advantages over arginine, including a more targeted role in human metabolism, increased bioavailability and absorption into the blood, and decreased side effects when administered orally ( Bahri et al., 2013 ; Collins et al., 2007
Tomohiro Okada and Yoh-ichi Matsubara
the changes in amino acid constituents related to disease tolerance in mycorrhizal plants, Baltruschat and Schonbeck (1975) demonstrated that the propagation of Thielaviopsis basicola was inhibited by the increase of arginine and citrulline in
Ignacio Lazcano-Ferrat and Carol J. Lovatt
Two lines of tepary bean, PI 321-638 and PI 319-443, were salinized at age 7 days with Shive's nutrient solution plus 60 mM NaCl-CaCl2 in a 2:1 molar ratio. Salt was added at the rate of 1/3 the final concentration every other day. The osmotic potential of the salinizing solution was -0.33 MPa. Fifteen days of salt treatment reduced plant growth 45% and inhibited the incorporation of NaH14CO3 into the combined pool of arginine plus urea 60 and 85% for the two lines, respectively. The salt sensitive step in the arginine biosynthetic pathway was identified as carbamylphosphate synthetase in both lines, Incorporation of [14C]citrulline and [14C]carbamylphosphate plus ornithine were not inhibited by the salt treatment, but the incorporation of NaH14CO3 remained inhibited even in the presence of added ornithine (10 mM). Inhibition at carbamylphosphate synthetase was confirmed by demonstration that the incorporation of NaH14CO3 into UMP was also inhibited by salt stress. Evidence is provided suggesting that reduced availability of ornithine additionally compromised both arginine and pyrimidine biosynthesis during salt stress.
Supported by the Citrus Research Center and Agricultural Experiment Station of the University of California, Riverside.
Oded Sagee and Carol J. Lovatt
Maximum leaf NH3-NH4 + content and activity of the de novo arginine biosynthetic pathway occurred during the 1st week after transfer of 5-year-old rooted cuttings of the `Washington' navel orange (Citrus sinensis L. Osbeck) from 8 weeks of low-temperature stress [8-hour days (500 μmol·s-1·m-2) at 15 to 18C/16-hour nights at 10 to 13C]. Both aspects declined in parallel during the subsequent 4 weeks of 12-hour days (500 μmol·s-1·m-2) at 24 C/12-hour nights at 19C, which culminated in maximum bloom. Apical flowers of inflorescences initiated in response to 8 weeks of low-temperature stress exhibited maximum tissue concentrations of NH3-NH4 + and putrescine, and maximum activity of the de novo arginine biosynthetic pathway 1 week after transfer of the trees from the low-temperature induction to the higher temperature (flower buds were 7 × 5 mm, length/width). All three criteria decreased in parallel as flowers developed through Stage V (petal fall). In contrast, spermine concentration increased 7-fold during Stage IV of flower development (flower opening). By Stage V, ovaries contained about equal concentrations of putrescine, spermidine, and spermine. The activity of the de novo tyrosine biosynthetic pathway exhibited a pattern of change independent of flower NH3-NH4 + concentration. Observed changes were not due to increased organ weight or size and persisted when the data were expressed per milligram protein. The results of this study demonstrate that leaves and floral buds undergo parallel changes in N metabolism in response to low-temperature, stress-induced flowering and provide evidence that flower NH3-NH4 + content and putrescine synthesis via argine are metabolically correlated during flower development in C. sinensis.
Yusheng Zheng and Carol J. Lovatt
Rough lemon seedlings [Citrus limon (L)] were hydroponically-cultured in complete Shive's nutrient solution (+K) or in Shive's nutrient solution with potassium omitted (-K) for a period of eight months. Fresh and dry weight of whole -K plants were reduced 4-fold (P<0.01). Nitrogen metabolism was monitored during this period in young, fully expanded leaves. Results showed that leaves of -K plants accumulated 2.5-fold more NH3-NH4 + than +K plants (P<0.01) and exhibited a concomitant increase in both activity of the de novo arginine biosynthetic pathway (2.5-fold) and free-arginine concentration (3.5-fold; P<0.001). Leaf proline content of -K plants increased 1.6-fold (P<0.05), while putrescine content increased 10-fold. Arginine decarboxylase activity was accelerated in -K plants.
Shahzad M.A. Basra and Carol J. Lovatt
sugars by the anthrone method ( Yemm and Willis, 1954 ), soluble protein ( Bradford, 1976 ), the free amino acids proline ( Chinard, 1952 ) and arginine by the method of Sakaguchi as described in van Pilsum et al. (1956) , total antioxidants using the
Sung-Do Oh and G. Bunemann
Asparagine and arginine contents in spur buds, leaf buds and terminal buds of shoot were compared in Fuji and Jonagold apple trees during dormant and growing season. Amino acid contents in dormant spur buds were significantly higher in Jonagold than in Fuji, whereas the amino acid contents in shoot bark were not different in two cultivars. Asparagine and arginine contents were considerably higher in leaf and terminal buds of shoot. This phenomenon was quite obvious in Fuji than Jonagold but there was no significant difference in asparagine and arginine contents in spur buds. Flower buds differentiated on summer pruned shoots had higher contents of asparagine and arginine as compared with weak spur buds in Fuji but this was not quite obvious in Jonagold. It suggested that the irregular spur size and poor development of spur buds in Fuji cultivar might be caused by the poor translocation of amino acids as well as nitrogen compounds from shoots and other vegetative organs.
Xinhua Zhang, Fujun Li, Nana Ji, Shujun Shao, Dongyang Wang, Ling Li, and Fansheng Cheng
Arginine is one of the most versatile amino acids in living cells. In addition to serving as a building block of proteins, arginine can positively modulate several subsequent ornithine-dependent pathways through its catabolism ( Gao et al., 2009
Zhijun Zhang, Huaifeng Liu, Junli Sun, Songlin Yu, Wang He, Tianyuan Li, and Zhao Baolong
. The concentrations of malvidin 3-(6-p-coumarylglucoside), N-acetyl-L-glutamate, L-arginine, pyridoxine, and adenosine were higher in the CS/140R rootstock combination than in other combinations, and the concentrations of L-glutamic acid