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971.
The precursory role of avenic acid A (AVA) in the biosynthesis of the mugineic acid family (MAs) of phytosiderophores was studied by feeding 14C or 15N labeled compounds into iron-deficient oat roots (Avena sativa L. cv. Onward). Carbon-14 of methionine was incorporated into AVA and 2-deoxymugineic acid (DMA) in the oat roots, while 14C of homoserine was not incorporated into either AVA or DMA. The molar radioactivity of DMA was higher than that of AVA. Incorporation of 15N into MAs was examined by feeding 15N-ammonium sulfate into oat roots. The value of 15N atom-% excess of DMA was higher than that of AVA.These results indicate that methionine, rather than homoserine, is the direct precursor of MAs in oat, which is similar to that in barley, and that AVA is not the precursor of the other MAs. 相似文献
972.
Barbara Dinkelaker Christine Hengeler H. Marschner 《Plant biology (Stuttgart, Germany)》1995,108(3):183-200
Proteoid roots are bottlebrush-like clusters of rootlets which form along lateral roots. They are characteristic of most species of the Proteaceae, which are mainly distributed in Australia and South Africa. Homologous root clusters are present in species of the Casuarinaceae, Mimosaceae, Fabaceae, Myricaceae and Moraceae. Many similarities exist between these species in relation to morphology and function of root clusters. Many are non-mycorrhizal and are highly efficient in phosphorus (P) acquisition. In these species, proteoid roots and proteoid-like root clusters are abundant when grown on infertile soils. Their formation is predominantly affected by the P status of the plants, being induced at low P levels and repressed at high P levels. Proteoid roots and proteoid-like root clusters play an important role in acquisition of P and other mineral nutrients. Although increase in root surface area may be a contributing factor, in many species these roots excrete large amounts of organic acids and phenolics. The excretion of these compounds in a small soil volume gives rise to extensive nutrient mobilization by acidification, reduction and chelation of sparingly soluble forms of P and micronutrients such as Fe and Mn. 相似文献
973.
974.
Iron deficiency-induced changes in the photosynthetic pigment composition of field-grown pear (Pyrus communis L) leaves 总被引:2,自引:1,他引:1
In this work we characterize the changes induced by iron deficiency in the pigment composition of pear (Pyrus communis L.) leaves grown under high light intensities in field conditions in Spain. Iron deficiency induced decreases in neoxanthin and β-carotene concomitantly with decreases in chlorophyll a, whereas lutein and carotenoids within the xanthophyll cycle were less affected. Iron deficiency caused major increases in the lutein/chlorophyll a and xanthophyll cycle pigments/chlorophyll a molar ratios. The chlorophyll a/chlorophyll b ratio increased in response to iron deficiency. The carotenoids within the xanthophyll cycle in iron-deficient and in iron-sufficient (control) leaves underwent epoxidations and de-epoxidations in response to ambient light conditions. In control leaves dark-adapted for several hours, most of the xanthophyll cycle pigment pool was in the epoxidated form vio-laxanthin, whereas iron-deficient leaves had significant amounts of zeaxanthin. Iron-deficient leaves also exhibited an increased non-photochemical quenching, supporting the possibility of a role for pigments within the xanthophyll cycle in photoprotection. 相似文献
975.
A primary phosphorus‐deficient skeletal phenotype in juvenile Atlantic salmon Salmo salar: the uncoupling of bone formation and mineralization
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P. E. Witten M. A. G. Owen R. Fontanillas M. Soenens C. McGurk A. Obach 《Journal of fish biology》2016,88(2):690-708
To understand the effect of low dietary phosphorus (P) intake on the vertebral column of Atlantic salmon Salmo salar, a primary P deficiency was induced in post‐smolts. The dietary P provision was reduced by 50% for a period of 10 weeks under controlled conditions. The animal's skeleton was subsequently analysed by radiology, histological examination, histochemical detection of minerals in bones and scales and chemical mineral analysis. This is the first account of how a primary P deficiency affects the skeleton in S. salar at the cellular and at the micro‐anatomical level. Animals that received the P‐deficient diet displayed known signs of P deficiency including reduced growth and soft, pliable opercula. Bone and scale mineral content decreased by c. 50%. On radiographs, vertebral bodies appear small, undersized and with enlarged intervertebral spaces. Contrary to the X‐ray‐based diagnosis, the histological examination revealed that vertebral bodies had a regular size and regular internal bone structures; intervertebral spaces were not enlarged. Bone matrix formation was continuous and uninterrupted, albeit without traces of mineralization. Likewise, scale growth continues with regular annuli formation, but new scale matrix remains without minerals. The 10 week long experiment generated a homogeneous osteomalacia of vertebral bodies without apparent induction of skeletal malformations. The experiment shows that bone formation and bone mineralization are, to a large degree, independent processes in the fish examined. Therefore, a deficit in mineralization must not be the only cause of the alterations of the vertebral bone structure observed in farmed S. salar. It is discussed how the observed uncoupling of bone formation and mineralization helps to better diagnose, understand and prevent P deficiency‐related malformations in farmed S. salar. 相似文献
976.
Saud H. AlDubayan Marios Giannakis Nathanael D. Moore G. Celine Han Brendan Reardon Tsuyoshi Hamada Xinmeng Jasmine Mu Reiko Nishihara Zhirong Qian Li Liu Matthew B. Yurgelun Sapna Syngal Levi A. Garraway Shuji Ogino Charles S. Fuchs Eliezer M. Van Allen 《American journal of human genetics》2018,102(3):401-414
977.
M. Cecilia Poli Frédéric Ebstein Sarah K. Nicholas Marietta M. de Guzman Lisa R. Forbes Ivan K. Chinn Emily M. Mace Tiphanie P. Vogel Alexandre F. Carisey Felipe Benavides Zeynep H. Coban-Akdemir Richard A. Gibbs Shalini N. Jhangiani Donna M. Muzny Claudia M.B. Carvalho Deborah A. Schady Mahim Jain Jill A. Rosenfeld Jordan S. Orange 《American journal of human genetics》2018,102(6):1126-1142
978.
High vulnerability of the heart and liver to 3‐hydroxypalmitic acid–induced disruption of mitochondrial functions in intact cell systems
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Cristiane Cecatto Alessandro Wajner Carmen Regla Vargas Simone Magagnin Wajner Alexandre Umpierrez Amaral Moacir Wajner 《Journal of cellular biochemistry》2018,119(9):7678-7686
Patients affected by long‐chain 3‐hydroxyacyl‐CoA dehydrogenase (LCHAD) deficiency predominantly present severe liver and cardiac dysfunction, as well as neurological symptoms during metabolic crises, whose pathogenesis is still poorly known. In this study, we demonstrate for the first time that pathological concentrations of 3‐hydroxypalmitic acid (3HPA), the long‐chain hydroxyl fatty acid (LCHFA) that most accumulates in LCHAD deficiency, significantly decreased adenosine triphosphate‐linked and uncoupled mitochondrial respiration in intact cell systems consisting of heart fibers, cardiomyocytes, and hepatocytes, but less intense in diced forebrain. 3HPA also significantly reduced mitochondrial Ca2+ retention capacity and membrane potential in Ca2+‐loaded mitochondria more markedly in the heart and the liver, with mild or no effects in the brain, supporting a higher susceptibility of the heart and the liver to the toxic effects of this fatty acid. It is postulated that disruption of mitochondrial energy and Ca2+ homeostasis caused by the accumulation of LCHFA may contribute toward the severe cardiac and hepatic clinical manifestations observed in the affected patients. 相似文献
979.
Esmond Lee Jaichandran Sivalingam Zhong Ri Lim Gloryn Chia Low Gin Shi Mackenna Roberts Yuin-Han Loh Shaul Reuveny Steve Kah-Weng Oh 《Biotechnology advances》2018,36(8):2118-2128
In vitro generation of red blood cells (RBCs) has the potential to circumvent the shortfalls in global demand for blood for transfusion applications. The conventional approach for RBC generation has been from differentiation of hematopoietic stem cells (HSCs) derived from cord blood, adult bone marrow or peripheral blood. More recently, RBCs have been generated from human induced pluripotent stem cells (hiPSCs) as well as from immortalized adult erythroid progenitors. In this review, we highlight the recent advances to RBC generation from these different approaches and discuss the challenges and new strategies that can potentially make large-scale in vitro generation of RBCs a feasible approach. 相似文献
980.
Strigolactones in plant adaptation to abiotic stresses: An emerging avenue of plant research
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Weiqiang Li Kien Huu Nguyen Masayuki Fujita Lam‐Son Phan Tran 《Plant, cell & environment》2018,41(10):2227-2243
Phytohormones play central roles in boosting plant tolerance to environmental stresses, which negatively affect plant productivity and threaten future food security. Strigolactones (SLs), a class of carotenoid‐derived phytohormones, were initially discovered as an “ecological signal” for parasitic seed germination and establishment of symbiotic relationship between plants and beneficial microbes. Subsequent characterizations have described their functional roles in various developmental processes, including root development, shoot branching, reproductive development, and leaf senescence. SLs have recently drawn much attention due to their essential roles in the regulation of various physiological and molecular processes during the adaptation of plants to abiotic stresses. Reports suggest that the production of SLs in plants is strictly regulated and dependent on the type of stresses that plants confront at various stages of development. Recently, evidence for crosstalk between SLs and other phytohormones, such as abscisic acid, in responses to abiotic stresses suggests that SLs actively participate within regulatory networks of plant stress adaptation that are governed by phytohormones. Moreover, the prospective roles of SLs in the management of plant growth and development under adverse environmental conditions have been suggested. In this review, we provide a comprehensive discussion pertaining to SL‐mediated plant responses and adaptation to abiotic stresses. 相似文献