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Huang XL, Zhuang YQ, Xiong YY, Li DW, Ou LJ. Efficient modulation of cellular phosphorus components in response to phosphorus deficiency in the dinoflagellate Karenia mikimotoi. Appl Environ Microbiol 2023; 89:e0086723. [PMID: 37850723 PMCID: PMC10686090 DOI: 10.1128/aem.00867-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/29/2023] [Indexed: 10/19/2023] Open
Abstract
IMPORTANCE Dinoflagellates are the most common phytoplankton group and account for more than 75% of harmful algal blooms in coastal waters. In recent decades, dinoflagellates seem to prevail in phosphate-depleted waters. However, the underlying acclimation mechanisms and competitive strategies of dinoflagellates in response to phosphorus deficiency are poorly understood, especially in terms of intracellular phosphorus modulation and recycling. Here, we focused on the response of intracellular phosphorus metabolism to phosphorus deficiency in the model dinoflagellate Karenia mikimotoi. Our work reveals the strong capability of K. mikimotoi to efficiently regulate intracellular phosphorus resources, particularly through membrane phospholipid remodeling and miRNA regulation of energy metabolism. Our research improved the understanding of intracellular phosphorus metabolism in marine phytoplankton and underscored the advantageous strategies of dinoflagellates in the efficient modulation of internal phosphorus resources to maintain active physiological activity and growth under unsuitable phosphorus conditions, which help them outcompete other species in coastal phosphate-depleted environments.
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Affiliation(s)
- Xue-Ling Huang
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Yan-Qing Zhuang
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Yue-Yue Xiong
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Da-Wei Li
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Lin-Jian Ou
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
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Xia M, Ma X, Liu J, Wu M, Li Z, Liu M. Potential effect of key soil bacterial taxa on the increase of rice yield under milk vetch rotation. Front Microbiol 2023; 14:1150505. [PMID: 37283927 PMCID: PMC10241072 DOI: 10.3389/fmicb.2023.1150505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/28/2023] [Indexed: 06/08/2023] Open
Abstract
Legume crop rotation is often adopted in rice cultivation to improve soil productivity. However, little is known about the role of microbes under legume rotation in affecting soil productivity. To elucidate this, a long-term paddy cropping experiment was set up to study the relationship between crop yield, soil chemical properties, and key microbial taxa under a double-rice and milk vetch rotation. Milk vetch rotation significantly improved soil chemical properties compared to no fertilization treatment, and soil phosphorus was a major factor correlated with crop yield. Long-term legume rotation increased soil bacterial alpha diversity and changed soil bacterial community. After milk vetch rotation, the relative abundances of Bacteroidota, Desulfobacterota, Firmicutes, and Proteobacteria increased while those of Acidobacteriota, Chloroflexi, and Planctomycetota decreased. Moreover, milk vetch rotation increased the relative abundance of phosphorus-related gene K01083 (bpp), which was significantly correlated with soil phosphorus content and crop yield. Network analysis showed that taxa of Vicinamibacterales were positively correlated with total phosphorus and available phosphorus, which was a potential taxon contributing to the availability of soil phosphorus stock. Our results indicated that milk vetch rotation could enrich key taxa with latent phosphate-solubilizing ability, increase the content of soil available phosphorus, and finally enhance crop yield. This could provide scientific guidance for better crop production.
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Affiliation(s)
- Mingming Xia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xinling Ma
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jia Liu
- National Engineering and Technology Research Center for Red Soil Improvement, Soil and Fertilizer & Resources and Environment Institute, Jiangxi Academy of Agricultural Sciences, Nanchang, China
| | - Meng Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhongpei Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ming Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
- Ecological Experimental Station of Red Soil Academia Sinica, Nanjing, China
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Jiang C, Xu S, Wang R, Sun Q, Zuo J, Zhuang X. Transcriptomics Insights into Phosphorus Stress Response of Myriophyllum aquaticum. Int J Mol Sci 2023; 24. [PMID: 36902302 DOI: 10.3390/ijms24054874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/31/2023] [Accepted: 02/07/2023] [Indexed: 03/06/2023] Open
Abstract
Through excellent absorption and transformation, the macrophyte Myriophyllum (M.) aquaticum can considerably remove phosphorus from wastewater. The results of changes in growth rate, chlorophyll content, and roots number and length showed that M. aquaticum could cope better with high phosphorus stress compared with low phosphorus stress. Transcriptome and differentially expressed genes (DEGs) analyses revealed that, when exposed to phosphorus stresses at various concentrations, the roots were more active than the leaves, with more DEGs regulated. M. aquaticum also showed different gene expression and pathway regulatory patterns when exposed to low phosphorus and high phosphorus stresses. M. aquaticum's capacity to cope with phosphorus stress was maybe due to its improved ability to regulate metabolic pathways such as photosynthesis, oxidative stress reduction, phosphorus metabolism, signal transduction, secondary metabolites biosynthesis, and energy metabolism. In general, M. aquaticum has a complex and interconnected regulatory network that deals efficiently with phosphorus stress to varying degrees. This is the first time that the mechanisms of M. aquaticum in sustaining phosphorus stress have been fully examined at the transcriptome level using high-throughput sequencing analysis, which may indicate the direction of follow-up research and have some guiding value for its future applications.
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Hofmann C, Kienzle E, Dobenecker B. Faecal dry matter excretion per se affects faecal calcium and phosphorus losses in dogs. J Anim Physiol Anim Nutr (Berl) 2022; 106:1364-1367. [PMID: 35934936 DOI: 10.1111/jpn.13762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 06/28/2022] [Accepted: 07/26/2022] [Indexed: 11/26/2022]
Abstract
The study aimed to investigate the effect of faecal dry matter (DM) excretion on faecal losses of calcium (Ca) and phosphorus (P) without potentially confounding factors. Dogs were fed two levels of the same basal diet (cooked pork, rice, gelatine; 8.5 ± 0.7 and 12.6 ± 1.2 g DM/kg BW). Mineral supplements were added separately for identical Ca and P supply independent of DM intake (Ca 226 and P ~170 mg/kg BW). Digestion trials (10 days adaptation, 5 days quantitative faecal collection) were carried out. Digestibility of DM averaged 87% in both trials. Faecal DM and mineral excretion increased highly significant (DM 1.1 ± 0.3 to 1.7 ± 0.2 g/kg BW, p = 0.00005; Ca 185 ± 34 and 233 ± 22 mg/kg BW, p = 0.00119; P 99 ± 23 to 127 ± 12 mg/kg BW, p = 0.00212), revealing a highly significant correlation. Apparent digestibility of Ca was positive in the first trial and negative in the second leading to a slightly negative Ca retention in the latter one. The results suggest that in dogs (i) factors influencing Ca and P absorption can only be compared if faecal DM excretion is identical and (ii) Ca requirements may be affected by DM intake and digestibility.
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Affiliation(s)
- Celina Hofmann
- Department of Veterinary Science, Faculty of Veterinary Medicine, Chair of Animal Nutrition and Dietetics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Ellen Kienzle
- Department of Veterinary Science, Faculty of Veterinary Medicine, Chair of Animal Nutrition and Dietetics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Britta Dobenecker
- Department of Veterinary Science, Faculty of Veterinary Medicine, Chair of Animal Nutrition and Dietetics, Ludwig-Maximilians-Universität München, Munich, Germany
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Dittmer KE, Chernyavtseva A, Marshall JC, Cabrera D, Wolber FM, Kruger M. Expression of Renal Vitamin D and Phosphatonin-Related Genes in a Sheep Model of Osteoporosis. Animals (Basel) 2021; 12:ani12010067. [PMID: 35011173 PMCID: PMC8749731 DOI: 10.3390/ani12010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/23/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Osteoporosis is a significant public health issue around the world, with post-menopausal osteoporosis due to estrogen deficiency resulting in approximately ¾ of cases. Treatment with glucocorticoids is another common cause of osteoporosis in humans. Sheep are a well-established model for osteoporosis in humans. In this study, aged sheep had their ovaries removed (ovariectomy) to simulate estrogen deficiency, and some sheep were also treated with glucocorticoids. The results showed that expression of the gene klotho in the kidney had the most marked difference in ovariectomized sheep treated with glucocorticoids for 2 months followed by a recovery period of 3 months. Klotho is known as the “anti-aging” hormone and is an important regulator of calcium and phosphorus metabolism. It may therefore be involved in the recovery of bone mineral density seen in ovariectomized sheep treated with glucocorticoids for 2 months followed by euthanasia at 5 months. As such, it could be an important treatment target for osteoporosis in humans. Abstract Osteoporosis is a significant public health issue around the world, with post-menopausal osteoporosis due to estrogen deficiency resulting in approximately ¾ of cases. In this study, 18 aged Merino ewes were ovariectomized, and 10 were controls. Three of the ovariectomized ewes were treated weekly with 400 mg of methylprednisolone for 5 months and three were treated weekly for 2 months, followed by a 3-month recovery period. At 2 months, five control animals and six ovariectomized animals were euthanized. At 5 months, all the remaining ewes were euthanized. Kidney samples were collected postmortem for qPCR analysis of NPT1, PTH1R, NPT2a, NPT2c, Klotho, FGFR1IIIc, VDR, CYP24A1, CYP27B1, TRPV5, TRPV6, CalD9k, CalD28k, PMCA and NCX1. Ovariectomized sheep had significantly greater VDR expression compared with other groups. Ovariectomized sheep treated with glucocorticoids for 2 months followed by euthanasia at 5 months showed significant differences in TRPV5, CYP24A1 and klotho gene expression compared to other groups. Differences in klotho expression were most marked after adjustment for repeated measures (p = 0.1). Klotho is known as the “anti-aging” hormone and is involved in calcium and phosphorus metabolism. Klotho may be involved in the recovery of bone mineral density in ovariectomized sheep treated with glucocorticoids for 2 months followed by euthanasia at 5 months. Further research on the role of klotho is recommended.
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Affiliation(s)
- Keren E. Dittmer
- School of Veterinary Science, Massey University, Palmerston North 4442, New Zealand;
- Correspondence:
| | | | - Jonathan C. Marshall
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand;
| | - Diana Cabrera
- School of Food and Advanced Technology, Massey University, Palmerston North 4442, New Zealand; (D.C.); (F.M.W.)
| | - Frances M. Wolber
- School of Food and Advanced Technology, Massey University, Palmerston North 4442, New Zealand; (D.C.); (F.M.W.)
| | - Marlena Kruger
- School of Health Sciences, Massey University, Palmerston North 4442, New Zealand;
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Papadopoulou A, Bountouvi E, Karachaliou FE. The Molecular Basis of Calcium and Phosphorus Inherited Metabolic Disorders. Genes (Basel) 2021; 12:genes12050734. [PMID: 34068220 PMCID: PMC8153134 DOI: 10.3390/genes12050734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca) and Phosphorus (P) hold a leading part in many skeletal and extra-skeletal biological processes. Their tight normal range in serum mirrors their critical role in human well-being. The signalling “voyage” starts at Calcium Sensing Receptor (CaSR) localized on the surface of the parathyroid glands, which captures the “oscillations” of extracellular ionized Ca and transfers the signal downstream. Parathyroid hormone (PTH), Vitamin D, Fibroblast Growth Factor (FGF23) and other receptors or ion-transporters, work synergistically and establish a highly regulated signalling circuit between the bone, kidneys, and intestine to ensure the maintenance of Ca and P homeostasis. Any deviation from this well-orchestrated scheme may result in mild or severe pathologies expressed by biochemical and/or clinical features. Inherited disorders of Ca and P metabolism are rare. However, delayed diagnosis or misdiagnosis may cost patient’s quality of life or even life expectancy. Unravelling the thread of the molecular pathways involving Ca and P signaling, we can better understand the link between genetic alterations and biochemical and/or clinical phenotypes and help in diagnosis and early therapeutic intervention.
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Pramanik K, Das A, Banerjee J, Das A, Chatterjee S, Sharma R, Kumar S, Gupta S. Metagenomic Insights into Rhizospheric Microbiome Profiling in Lentil Cultivars Unveils Differential Microbial Nitrogen and Phosphorus Metabolism under Rice-Fallow Ecology. Int J Mol Sci 2020; 21:E8895. [PMID: 33255324 DOI: 10.3390/ijms21238895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/06/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023] Open
Abstract
The plant rhizosphere interfaces an array of microbiomes related to plant growth and development. Cultivar-specific soil microbial communities with respect to their taxonomic structure and specific function have not been investigated explicitly in improving the adaptation of lentil cultivars under rice-fallow ecology. The present study was carried out to decipher the rhizosphere microbiome assembly of two lentil cultivars under rice-fallow ecology for discerning the diversity of microbial communities and for predicting the function of microbiome genes related to nitrogen (N) and phosphorus (P) cycling processes deploying high-throughput whole (meta) genome sequencing. The metagenome profile of two cultivars detected variable microbiome composition with discrete metabolic activity. Cyanobacteria, Bacteroidetes, Proteobacteria, Gemmatimonadetes, and Thaumarchaeota were abundant phyla in the “Farmer-2” rhizosphere, whereas Actinobacteria, Acidobacteria, Firmicutes, Planctomycetes, Chloroflexi, and some incompletely described procaryotes of the “Candidatus” category were found to be robustly enriched the rhizosphere of “Moitree”. Functional prediction profiles of the microbial metagenomes between two cultivars revealed mostly house keeping genes with general metabolism. Additionally, the rhizosphere of “Moitree” had a high abundance of genes related to denitrification processes. Significant difference was observed regarding P cycling genes between the cultivars. “Moitree” with a profuse root system exhibited better N fixation and translocation ability due to a good “foraging strategy” for improving acquisition of native P under the nutrient depleted rice-fallow ecology. However, “Farmer-2” revealed a better “mining strategy” for enhancing P solubilization and further transportation to sinks. This study warrants comprehensive research for explaining the role of microbiome diversity and cultivar–microbe interactions towards stimulating microbiome-derived soil reactions regarding nutrient availability under rice-fallow ecology.
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Iida A, Matsushita M, Ohta T, Yamada T. Conventional and novel impacts of ferric citrate on iron deficiency anemia and phosphorus metabolism in rats. J Vet Med Sci 2020; 82:379-386. [PMID: 31996496 PMCID: PMC7118491 DOI: 10.1292/jvms.19-0641] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ferric citrate is an oral iron-based phosphate binder, being known to affect iron status and improve iron deficiency anemia (IDA) in chronic kidney disease (CKD) patients. We examined
whether oral administration of ferric citrate could change iron status and improve anemia without affecting phosphorus metabolism in iron deficiency anemia rats. In Normal rat study, normal
rats were fed a diet containing 0.3 or 3% ferric citrate for 11 days for setting the dose and administration period of ferric citrate. The effects of ferric citrate on iron status- and
phosphorus metabolism-related parameters were evaluated using blood and urine samples. Next, an iron deficiency anemia was induced by feeding iron-depleted diet in rats. After 7 days of
starting the iron-depleted diet, 0.3% ferric citrate was administered for 7 days by dietary admixture. Iron status- and phosphorus metabolism-related parameters were evaluated with blood and
urine samples. In Normal rat study, 3% ferric citrate treatment increased serum iron level and transferrin saturation (TSAT), and decreased serum phosphorus level, intact fibroblast growth
factor 23 (iFGF23) level, and urinary phosphorus excretion, but 0.3% ferric citrate treatment showed no effects. On the other hand, in Iron deficiency anemia rat study, 0.3% ferric citrate
treatment increased iron status-related parameters and improved anemia, but did not show any apparent changes in phosphorus metabolism-related parameters. In conclusion, ferric citrate could
have hematopoietic effects without affecting phosphorus metabolism, and could be a potential option for the treatment of IDA in patients without CKD.
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Affiliation(s)
- Akio Iida
- Biological/Pharmacological Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.,Department of Agrobiology, Faculty of Agriculture, Niigata University, 2-8050 Igarashi, Nishiku, Niigata 950-2181, Japan
| | - Mutsuyoshi Matsushita
- Biological/Pharmacological Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Takeshi Ohta
- Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takahisa Yamada
- Department of Agrobiology, Faculty of Agriculture, Niigata University, 2-8050 Igarashi, Nishiku, Niigata 950-2181, Japan
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Notsumata K, Nomura Y, Tanaka A, Ueda T, Sanada T, Watanabe H, Toya D. Early changes in tubular dysfunction markers and phosphorus metabolism regulators as a result of switching from entecavir to tenofovir alafenamide fumarate nucleoside analog therapy for chronic hepatitis B patients. Hepatol Res 2020; 50:402-404. [PMID: 31692220 DOI: 10.1111/hepr.13451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 10/20/2019] [Accepted: 10/24/2019] [Indexed: 02/08/2023]
Affiliation(s)
- Kazuo Notsumata
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Yoshimoto Nomura
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Akihiro Tanaka
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Teruyuki Ueda
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Taku Sanada
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Hiroyuki Watanabe
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
| | - Daishu Toya
- Department of General Internal Medicine, Fukui-ken Saiseikai Hospital, 7-1 WadanakachoFunahashi, Fukui-shi, Fukui-ken, Japan
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Zhou L, Declerck SAJ. Herbivore consumers face different challenges along opposite sides of the stoichiometric knife-edge. Ecol Lett 2019; 22:2018-2027. [PMID: 31512359 PMCID: PMC6900088 DOI: 10.1111/ele.13386] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/01/2019] [Accepted: 08/14/2019] [Indexed: 02/06/2023]
Abstract
Anthropogenic activities have reshaped the relative supply rates of essential elements to organisms. Recent studies suggested that consumer performance is strongly reduced by food that is either very high or very low in relative phosphorus content. However, the generality of such 'stoichiometric knife-edge' and its underlying mechanisms are poorly understood. We studied the response of a planktonic rotifer to a 10-fold food carbon : phosphorus (C : P) gradient and confirmed the existence of the stoichiometric knife-edge. Interestingly, we observed a complete homeostatic breakdown associated with strong growth reductions at high food C : P. In contrast, at low food C : P, animals maintained homeostasis despite pronounced performance reductions. Our results suggest that the mechanisms underlying adverse effects of stoichiometric imbalance are determined by both the identity of elements that are limiting and those that are present in excess. Negative effects of excess P reveal an additional way of how eutrophication may affect consumers.
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Affiliation(s)
- Libin Zhou
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
| | - Steven A J Declerck
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
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Cai D, Zhu J, Zhu S, Lu Y, Zhang B, Lu K, Li J, Ma X, Chen S. Metabolic Engineering of Main Transcription Factors in Carbon, Nitrogen, and Phosphorus Metabolisms for Enhanced Production of Bacitracin in Bacillus licheniformis. ACS Synth Biol 2019; 8:866-875. [PMID: 30865822 DOI: 10.1021/acssynbio.9b00005] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Primary metabolism plays a key role in the synthesis of secondary metabolite. In this study, the main transcription factors in carbon, nitrogen, and phosphorus metabolisms (CcpA, CcpC, CcpN, CodY, TnrA, GlnR, and PhoP) were engineered to improve bacitracin yield in Bacillus licheniformis DW2, an industrial strain for bacitracin production. First, our results demonstrated that deletions of ccpC and ccpN improved ATP and NADPH supplies, and the bacitracin yields were respectively increased by 14.02% and 16.06% compared with that of DW2, while it was decreased significantly in ccpA deficient strain DW2ΔccpA. Second, excessive branched chain amino acids (BCAAs) were accumulated in codY, tnrA, and glnR deletion strains DW2ΔcodY, DW2ΔtnrA, and DW2ΔglnR, which resulted in the nitrogen catabolite repressions and reductions of bacitracin yields. Moreover, overexpression of these regulators improved intracellular BCAA supplies, and further enhanced bacitracin yields by 14.17%, 12.98%, and 16.20%, respectively. Furthermore, our results confirmed that phosphate addition reduced bacitracin synthesis capability, and bacitracin yield was improved by 15.71% in gene phop deletion strain. On the contrary, overexpression of PhoP led to a 19.40% decrease of bacitracin yield. Finally, a combinatorial engineering of these above metabolic manipulations was applied, and bacitracin yield produced by the final strain DW2-CNCTGP (Simultaneously deleting ccpC, ccpN, phop and overexpressing glnR, codY, and tnrA in DW2) reached 1014.38 U/mL, increased by 35.72% compared to DW2, and this yield was the highest bacitracin yield currently reported. Taken together, this study implied that metabolic engineering of carbon, nitrogen, and phosphorus metabolism regulators is an efficient strategy to enhance bacitracin production, and provided a promising B. licheniformis strain for industrial production of bacitracin.
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Affiliation(s)
- Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jiang Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Shan Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yu Lu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Bowen Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Kai Lu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Junhui Li
- Lifecome Biochemistry Co., Ltd., Nanping 353400, PR China
| | - Xin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
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Frischkorn KR, Haley ST, Dyhrman ST. Transcriptional and Proteomic Choreography Under Phosphorus Deficiency and Re-supply in the N 2 Fixing Cyanobacterium Trichodesmium erythraeum. Front Microbiol 2019; 10:330. [PMID: 30891009 PMCID: PMC6411698 DOI: 10.3389/fmicb.2019.00330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/08/2019] [Indexed: 01/27/2023] Open
Abstract
The N2 fixing cyanobacterium Trichodesmium is a critically important organism in oligotrophic marine ecosystems, supplying “new” nitrogen (N) to the otherwise N-poor tropical and subtropical regions where it occurs. Low concentrations of phosphorus (P) in these regions can constrain Trichodesmium distribution and N2 fixation rates. Physiological characterization of a single species in a mixed community can be challenging, and ‘omic approaches are increasingly important tools for tracking nutritional physiology in a taxon-specific manner. As such, studies examining the dynamics of gene and protein markers of physiology (e.g., nutrient stress) are critical for the application and interpretation of such ‘omic data in situ. Here we leveraged combined transcriptomics, proteomics, and enzyme activity assays to track the physiological response of Trichodesmium erythraeum IMS101 to P deficiency and subsequent P re-supply over 72 h of sampling. P deficiency resulted in differential gene expression, protein abundance, and enzyme activity that highlighted a synchronous shift in P physiology with increases in the transcripts and corresponding proteins for hydrolyzing organic phosphorus, taking up phosphate with higher affinity, and modulating intracellular P demand. After P deficiency was alleviated, gene expression of these biomarkers was reduced to replete levels within 4 h of P amendment. A number of these gene biomarkers were adjacent to putative pho boxes and their expression patterns were similar to a sphR response regulator. Protein products of the P deficiency biomarkers were slow to decline, with 84% of the original P deficient protein set still significantly differentially expressed after 72 h. Alkaline phosphatase activity tracked with proteins for this enzyme. With the rapid turnover time of transcripts, they appear to be good biomarkers of a P stress phenotype, whereas proteins, with a slower turnover time, may better reflect cellular activities. These results highlight the importance of validating and pairing transcriptome and proteome data that can be applied to physiological studies of key species in situ.
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Affiliation(s)
- Kyle R Frischkorn
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sheean T Haley
- Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sonya T Dyhrman
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
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Abstract
BACKGROUND Recent evidence has shown that nicotinamide treatment may have an impact on phosphorus metabolism in hemodialysis patients. Nevertheless, the treatment remains controversial. This study aimed to precisely estimate the efficacy and safety of nicotinamide on phosphorus, calcium and iPTH in hemodialysis patients. METHODS We searched numerous information sources regarding randomized controlled trials (RCTs) of nicotinamide treatment in hemodialysis patients, including PubMed, EMBASE, and the Cochrane Library. RESULTS Nine relevant studies (n = 428) were included in the meta-analysis. Meta-analysis showed that levels of serum phosphorus (SMD -1.06; 95% CI, -1.27 to -0.85, P < .001), parathyroid hormone (SMD -1.09; 95% CI, -1.49 to -0.70, P < .001), and calcium-phosphorus (SMD -0.65; 95% CI, -0.97 to -0.34, P < .001) in the nicotinamide group were significantly lower than those of the control group. There was no significant difference in the levels of serum calcium (SMD 0.08; 95% CI, -0.15 to 0.30, P = .51) between the groups. The meta-analysis showed that the nicotinamide group had a significantly higher risk of adverse events (OR 3.99; 95% CI, 1.94-8.23, P < .001) than did the control group, especially for thrombocytopenia (OR 49.00; 95% CI, 2.68-897.36, P = .009). However, no serious adverse reactions were observed. There was no significant difference in the incidence of withdrawal (OR 3.51; 95% CI, 0.49-25.00, P = .21) between the groups. CONCLUSION Evidence to date clearly indicates that nicotinamide is safe and effective for improving phosphorus metabolism in hemodialysis patients. However, nicotinamide probably causes thrombocytopenia. Further large-sample size, high-quality RCTs are needed.
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Motomura K, Sano K, Watanabe S, Kanbara A, Gamal Nasser AH, Ikeda T, Ishida T, Funabashi H, Kuroda A, Hirota R. Synthetic Phosphorus Metabolic Pathway for Biosafety and Contamination Management of Cyanobacterial Cultivation. ACS Synth Biol 2018; 7:2189-2198. [PMID: 30203964 DOI: 10.1021/acssynbio.8b00199] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent progress in genetic engineering and synthetic biology have greatly expanded the production capabilities of cyanobacteria, but concerns regarding biosafety issues and the risk of contamination of cultures in outdoor culture conditions remain to be resolved. With this dual goal in mind, we applied the recently established biological containment strategy based on phosphite (H3PO3, Pt) dependency to the model cyanobacterium Synechococcus elongatus PCC 7942 ( Syn 7942). Pt assimilation capability was conferred on Syn 7942 by the introduction of Pt dehydrogenase (PtxD) and hypophosphite transporter (HtxBCDE) genes that allow the uptake of Pt, but not phosphate (H3PO4, Pi). We then identified and disrupted the two indigenous Pi transporters, pst (Synpcc7942_2441 to 2445) and pit (Synpcc7942_0184). The resultant strain failed to grow on any media containing various types of P compounds other than Pt. The strain did not yield any escape mutants for at least 28 days with a detection limit of 3.6 × 10-11 per colony forming unit, and rapidly lost viability in the absence of Pt. Moreover, growth competition of the Pt-dependent strain with wild-type cyanobacteria revealed that the Pt-dependent strain could dominate in cultures containing Pt as the sole P source. Because Pt is rarely available in aquatic environments this strategy can contribute to both biosafety and contamination management of genetically engineered cyanobacteria.
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Affiliation(s)
- Kei Motomura
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Kosuke Sano
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Satoru Watanabe
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Akihiro Kanbara
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Abdel-Hady Gamal Nasser
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takeshi Ikeda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takenori Ishida
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Hisakage Funabashi
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Akio Kuroda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Ryuichi Hirota
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
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Casey JR, Mardinoglu A, Nielsen J, Karl DM. Adaptive Evolution of Phosphorus Metabolism in Prochlorococcus. mSystems 2016; 1:e00065-16. [PMID: 27868089 DOI: 10.1128/mSystems.00065-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 10/17/2016] [Indexed: 01/05/2023] Open
Abstract
Microbes are known to employ three basic strategies to compete for limiting elemental resources: (i) cell quotas may be adjusted by alterations to cell physiology or by substitution of a more plentiful resource, (ii) stressed cells may synthesize high-affinity transporters, and (iii) cells may access more costly sources from internal stores, by degradation, or by petitioning other microbes. In the case of phosphorus, a limiting resource in vast oceanic regions, the cosmopolitan cyanobacterium Prochlorococcus marinus thrives by adopting all three strategies and a fourth, previously unknown strategy. By generating a detailed model of its metabolism, we found that strain MED4 has evolved a way to reduce its dependence on phosphate by minimizing the number of enzymes involved in phosphate transformations, despite the stringency of nearly half of its metabolic genes being essential for survival. Relieving phosphorus limitation, both physiologically and throughout intermediate metabolism, substantially improves phosphorus-specific growth rates. Inorganic phosphorus is scarce in the eastern Mediterranean Sea, where the high-light-adapted ecotype HLI of the marine picocyanobacterium Prochlorococcus marinus thrives. Physiological and regulatory control of phosphorus acquisition and partitioning has been observed in HLI both in culture and in the field; however, the optimization of phosphorus metabolism and associated gains for its phosphorus-limited-growth (PLG) phenotype have not been studied. Here, we reconstructed a genome-scale metabolic network of the HLI axenic strain MED4 (iJC568), consisting of 568 metabolic genes in relation to 794 reactions involving 680 metabolites distributed in 6 subcellular locations. iJC568 was used to quantify metabolic fluxes under PLG conditions, and we observed a close correspondence between experimental and computed fluxes. We found that MED4 has minimized its dependence on intracellular phosphate, not only through drastic depletion of phosphorus-containing biomass components but also through network-wide reductions in phosphate-reaction participation and the loss of a key enzyme, succinate dehydrogenase. These alterations occur despite the stringency of having relatively few pathway redundancies and an extremely high proportion of essential metabolic genes (47%; defined as the percentage of lethal in silico gene knockouts). These strategies are examples of nutrient-controlled adaptive evolution and confer a dramatic growth rate advantage to MED4 in phosphorus-limited regions. IMPORTANCE Microbes are known to employ three basic strategies to compete for limiting elemental resources: (i) cell quotas may be adjusted by alterations to cell physiology or by substitution of a more plentiful resource, (ii) stressed cells may synthesize high-affinity transporters, and (iii) cells may access more costly sources from internal stores, by degradation, or by petitioning other microbes. In the case of phosphorus, a limiting resource in vast oceanic regions, the cosmopolitan cyanobacterium Prochlorococcus marinus thrives by adopting all three strategies and a fourth, previously unknown strategy. By generating a detailed model of its metabolism, we found that strain MED4 has evolved a way to reduce its dependence on phosphate by minimizing the number of enzymes involved in phosphate transformations, despite the stringency of nearly half of its metabolic genes being essential for survival. Relieving phosphorus limitation, both physiologically and throughout intermediate metabolism, substantially improves phosphorus-specific growth rates.
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16
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Hui Q, Yang R, Shen C, Zhou Y, Gu Z. Mechanism of Calcium Lactate Facilitating Phytic Acid Degradation in Soybean during Germination. J Agric Food Chem 2016; 64:5564-73. [PMID: 27324823 DOI: 10.1021/acs.jafc.6b01598] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Calcium lactate facilitates the growth and phytic acid degradation of soybean sprouts, but the mechanism is unclear. In this study, calcium lactate (Ca) and calcium lactate with lanthanum chloride (Ca+La) were used to treat soybean sprouts to reveal the relevant mechanism. Results showed that the phytic acid content decreased and the availability of phosphorus increased under Ca treatment. This must be due to the enhancement of enzyme activity related to phytic acid degradation. In addition, the energy metabolism was accelerated by Ca treatment. The energy status and energy metabolism-associated enzyme activity also increased. However, the transmembrane transport of calcium was inhibited by La(3+) and concentrated in intercellular space or between the cell wall and cell membrane; thus, Ca+La treatment showed reverse results compared with those of Ca treatment. Interestingly, gene expression did not vary in accordance with their enzyme activity. These results demonstrated that calcium lactate increased the rate of phytic acid degradation by enhancing growth, phosphorus metabolism, and energy metabolism.
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Affiliation(s)
- Qianru Hui
- College of Food Science and Technology, Nanjing Agricultural University , Nanjing, Jiangsu 210095, People's Republic of China
| | - Runqiang Yang
- College of Food Science and Technology, Nanjing Agricultural University , Nanjing, Jiangsu 210095, People's Republic of China
| | - Chang Shen
- College of Food Science and Technology, Nanjing Agricultural University , Nanjing, Jiangsu 210095, People's Republic of China
| | - Yulin Zhou
- College of Food Science and Technology, Nanjing Agricultural University , Nanjing, Jiangsu 210095, People's Republic of China
| | - Zhenxin Gu
- College of Food Science and Technology, Nanjing Agricultural University , Nanjing, Jiangsu 210095, People's Republic of China
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Gan H, Jiao Y, Jia J, Wang X, Li H, Shi W, Peng C, Polle A, Luo ZB. Phosphorus and nitrogen physiology of two contrasting poplar genotypes when exposed to phosphorus and/or nitrogen starvation. Tree Physiol 2016; 36:22-38. [PMID: 26420793 DOI: 10.1093/treephys/tpv093] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 08/17/2015] [Indexed: 05/11/2023]
Abstract
Phosphorus (P) and nitrogen (N) are the two essential macronutrients for tree growth and development. To elucidate the P and N physiology of woody plants during acclimation to P and/or N starvation, we exposed saplings of the slow-growing Populus simonii Carr (Ps) and the fast-growing Populus × euramericana Dode (Pe) to complete nutrients or starvation of P, N or both elements (NP). P. × euramericana had lower P and N concentrations and greater P and N amounts due to higher biomass production, thereby resulting in greater phosphorus use efficiency/N use efficiency (PUE/NUE) compared with Ps. Compared with the roots of Ps, the roots of Pe exhibited higher enzymatic activities in terms of acid phosphatases (APs) and malate dehydrogenase (MDH), which are involved in P mobilization, and nitrate reductase (NR), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH), which participate in N assimilation. The responsiveness of the transcriptional regulation of key genes encoding transporters for phosphate, ammonium and nitrate was stronger in Pe than in Ps. These results suggest that Pe possesses a higher capacity for P/N uptake and assimilation, which promote faster growth compared with Ps. In both poplars, P or NP starvation caused significant decreases in the P concentrations and increases in PUE. Phosphorus deprivation induced the activity levels of APs, phosphoenolpyruvate carboxylase and MDH in both genotypes. Nitrogen or NP deficiency resulted in lower N concentrations, amino acid levels, NR and GOGAT activities, and higher NUE in both poplars. Thus, in Ps and Pe, the mRNA levels of PHT1;5, PHT1;9, PHT2;1, AMT2;1 and NR increased in the roots, while PHT1;9, PHO1;H1, PHO2, AMT1;1 and NRT2;1 increased in the leaves during acclimation to P, N or NP deprivation. These results suggest that both poplars suppress P/N uptake, mobilization and assimilation during acclimation to P, N or NP starvation.
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Affiliation(s)
- Honghao Gan
- College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Yu Jiao
- Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Jingbo Jia
- College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Xinli Wang
- Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Hong Li
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Wenguang Shi
- College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Changhui Peng
- Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Andrea Polle
- Büsgen-Institute, Department of Forest Botany and Tree Physiology, Georg-August University, Büsgenweg 2, 37077 Göttingen, Germany
| | - Zhi-Bin Luo
- College of Life Sciences and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, PR China Key Laboratory of Environment and Ecology in Western China of Ministry of Education, College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, PR China
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Stigter KA, Plaxton WC. Molecular Mechanisms of Phosphorus Metabolism and Transport during Leaf Senescence. Plants (Basel) 2015; 4:773-98. [PMID: 27135351 PMCID: PMC4844268 DOI: 10.3390/plants4040773] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/30/2015] [Accepted: 12/08/2015] [Indexed: 11/16/2022]
Abstract
Leaf senescence, being the final developmental stage of the leaf, signifies the transition from a mature, photosynthetically active organ to the attenuation of said function and eventual death of the leaf. During senescence, essential nutrients sequestered in the leaf, such as phosphorus (P), are mobilized and transported to sink tissues, particularly expanding leaves and developing seeds. Phosphorus recycling is crucial, as it helps to ensure that previously acquired P is not lost to the environment, particularly under the naturally occurring condition where most unfertilized soils contain low levels of soluble orthophosphate (Pi), the only form of P that roots can directly assimilate from the soil. Piecing together the molecular mechanisms that underpin the highly variable efficiencies of P remobilization from senescing leaves by different plant species may be critical for devising effective strategies for improving overall crop P-use efficiency. Maximizing Pi remobilization from senescing leaves using selective breeding and/or biotechnological strategies will help to generate P-efficient crops that would minimize the use of unsustainable and polluting Pi-containing fertilizers in agriculture. This review focuses on the molecular mechanisms whereby P is remobilized from senescing leaves and transported to sink tissues, which encompasses the action of hormones, transcription factors, Pi-scavenging enzymes, and Pi transporters.
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Affiliation(s)
- Kyla A Stigter
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
| | - William C Plaxton
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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Abstract
PURPOSE We compared the 31P metabolites in different brain regions of patients with temporal lobe epilepsy (TLE) with those from controls. METHODS Ten control subjects and 11 patients with TLE were investigated with magnetic resonance imaging (MRI) and [31P]MR spectroscopic imaging (MRSI). [31P]MR spectra were selected from a variety of brain regions inside and outside the temporal lobe. RESULTS There were no asymmetries of inorganic phosphate (Pi), pH, or phosphomonoesters (PME) between regions in the left and right hemispheres of controls. In patients with TLE, Pi and pH were higher and PME was lower throughout the entire ipsilateral temporal lobe as compared with the contralateral side and there were no significant asymmetries outside the temporal lobe. The degree of ipsilateral/contralateral asymmetry for all three metabolites was substantially greater for the temporal lobe than for the frontal, occipital, and parietal lobes, and these asymmetries provided additional data for seizure localization. As compared with levels in controls, Pi and pH were increased and PME were decreased on the ipsilateral side in patients with TLE. There were changes in Pi, pH, and PME on the contralateral side in persons with epilepsy as compared with controls, contrary to changes on the ipsilateral side. CONCLUSIONS Our findings provide some insight into the metabolic changes that occur in TLE and may prove useful adjuncts for seizure focus lateralization or localization.
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Affiliation(s)
- J van der Grond
- Department of Radiology, University Hospital Utrecht, The Netherlands
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