851
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Xiang L, Li Y, Rolland F, Van den Ende W. Neutral invertase, hexokinase and mitochondrial ROS homeostasis: emerging links between sugar metabolism, sugar signaling and ascorbate synthesis. Plant Signal Behav 2011; 6:1567-73. [PMID: 21918379 PMCID: PMC3256386 DOI: 10.4161/psb.6.10.17036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [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: 06/23/2011] [Accepted: 06/23/2011] [Indexed: 05/18/2023]
Abstract
Alkaline/neutral invertases (A/N-Invs) are unique to plants and photosynthetic bacteria. Although considerable advances have been made in our understanding of sucrose metabolic enzymes in plants, the function of A/N-Invs remained puzzling. In a recent study, we have analyzed the subcellullar localization of a cytosolic (At-A/N-InvG, At1g35580) and a mitochondrial (At-A/N-InvA, At1g56560) Arabidopsis A/N-Inv. Unexpectedly, At-A/N-InvA knockout plants showed a more severe growth defect than At-A/N-InvG knockout plants and a link between the two A/N-Invs and oxidative stress defence was found. Overexpression of At-A/N-InvA and At-A/N-InvG in leaf mesophyll protoplasts reduced the activity of the ascorbate peroxidase 2 (APX2) promoter, that was stimulated by hydrogen peroxide and abscisic acid. It is discussed here how sugars and ascorbate might contribute to mitochondrial reactive oxygen species homeostasis. We hypothesize that both mitochondrial and cytosolic A/N-Invs and mitochondria-associated hexokinases are key mediators, integrating metabolic and sugar signalling processes.
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Affiliation(s)
- Li Xiang
- KULeuven; Lab of Molecular Plant Physiology Kasteelpark Arenberg; Leuven, Belgium
| | - Yi Li
- Functional Biology; Kasteelpark Arenberg; Leuven, Belgium
| | - Filip Rolland
- Functional Biology; Kasteelpark Arenberg; Leuven, Belgium
| | - Wim Van den Ende
- KULeuven; Lab of Molecular Plant Physiology Kasteelpark Arenberg; Leuven, Belgium
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852
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Roncal-Jimenez CA, Lanaspa MA, Rivard CJ, Nakagawa T, Sanchez-Lozada LG, Jalal D, Andres-Hernando A, Tanabe K, Madero M, Li N, Cicerchi C, Mc Fann K, Sautin YY, Johnson RJ. Sucrose induces fatty liver and pancreatic inflammation in male breeder rats independent of excess energy intake. Metabolism 2011; 60:1259-70. [PMID: 21489572 PMCID: PMC3137694 DOI: 10.1016/j.metabol.2011.01.008] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 02/07/2023]
Abstract
Fructose induces metabolic syndrome in rats; but studies have been criticized for using high concentrations of fructose that are not physiologic, for using only pure fructose, and for not controlling for energy intake. We tested the hypothesis that a 40% sucrose diet (containing 20% fructose) might induce features of metabolic syndrome in male breeder rats independent of excess energy intake. Male Sprague-Dawley breeder rats were pair fed 40% sucrose or isocaloric starch diet for 4 months and evaluated for metabolic syndrome and diabetes. In vitro studies were performed in rat insulinoma cells (RIN-m5F) exposed to uric acid, and markers of inflammation were assessed. Rats fed a 40% sucrose diet developed accelerated features of metabolic syndrome with up-regulation of fructose-dependent transporter Glut5 and fructokinase. Fatty liver and low-grade pancreatic inflammation also occurred. Uric acid was found to stimulate inflammatory mediators and oxidative stress in islet cells in vitro. Sucrose, at concentrations ingested by a subset of Americans, can accelerate metabolic syndrome, fatty liver, and type 2 diabetes mellitus in male breeder rats; and the effects are independent of excess energy intake.
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Affiliation(s)
- Carlos A Roncal-Jimenez
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO 80016, USA.
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853
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Abstract
Arabidopsis mutant hps1 that over-accumulates sucrose has enhanced sensitivity in almost all the aspects of plant responses to phosphate starvation. The detailed characterization of hps1 has led to the conclusion that sucrose is a global regulator of plant phosphate responses. Here, we show that hps1 is also hypersensitive to nitrogen and potassium deprivation, as well as to decreased levels of overall macronutrients. These results suggest that sucrose regulates plant deficiency responses to multiple nutrients and is part of a general response to nutrient deprivation.
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Affiliation(s)
- Mingguang Lei
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
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854
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Wood MJ, Mollison J, Harrild K, Ferguson E, McKay T, Srikantharajah A, Bell L, Bhattacharya S. A pragmatic RCT of conventional versus increased concentration sucrose in freezing and thawing solutions for human embryos. Hum Reprod 2011; 26:1987-96. [PMID: 21586432 PMCID: PMC3137387 DOI: 10.1093/humrep/der147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/28/2011] [Accepted: 04/11/2011] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Intact frozen-thawed embryos have a greater potential than damaged embryos to establish successful pregnancies. This study aimed to determine whether elevated concentrations of sucrose during freezing would increase the proportion of patients with ≥ 50% of embryos intact after thawing (primary outcome), and improve clinical outcome. METHODS In a two arm, parallel group, pragmatic trial, IVF/ICSI couples were randomized prospectively to have their supernumerary embryos frozen in a medium containing 0.1 M sucrose (control; n = 99) or 0.3 M sucrose (intervention; n = 102). RESULTS More control (74/99) than intervention (63/102) couples had at least one embryo thawed (P = 0.07). Significantly more (P = 0.005) intervention (53/63) than control (45/74) couples had ≥ 50% of embryos intact. Freezing in a medium containing 0.3 M sucrose increased by 3.4-fold [95% confidence interval (CI) (1.45, 7.82)] the likelihood of a couple having ≥ 50% of their embryos intact. In the fresh cycle, live birth rate per transfer was similar in the control (35/95) and intervention (36/93) groups (P = 0.91). More control (19/63) than intervention (9/59) couples had a live birth after frozen embryo transfer (P = 0.08). When fresh and frozen cycles were combined, fewer intervention (n = 102) than control (n = 99) couples had at least one live birth (42 versus 53%). The difference in cumulative live birth rate was not significant [hazard ratio = 0.75, 95% CI (0.49, 1.13); P = 0.17]. CONCLUSIONS Increasing the concentration of sucrose in the freezing medium improves embryo survival, but this is not reflected by increased cumulative birth rates. CLINICAL TRIALS REGISTRATION NUMBER ISRCTN93314892.
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Affiliation(s)
- M J Wood
- Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.
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855
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Abstract
In spite of a knowledge explosion in cariology science, dental caries still remains a misunderstood phenomenon by the clinicians. In order to effectively use the wide range of preventive and management strategies, it is imperative to look beyond those black and white spots that manifest on the tooth surfaces. This paper focuses on the revised versions of the etiopathogenesis and definition of dental caries disease in the present century.
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Affiliation(s)
- Carounanidy Usha
- Department of Dentistry, Pondicherry Institute of Medical Sciences, Pondicherry, India
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856
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Burton CL, Noble K, Fletcher PJ. Enhanced incentive motivation for sucrose-paired cues in adolescent rats: possible roles for dopamine and opioid systems. Neuropsychopharmacology 2011; 36:1631-43. [PMID: 21508935 DOI: 10.1038/npp.2011.44] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vulnerability to the effects of drugs of abuse during adolescence may be related to altered incentive motivation, a process believed to be important in addiction. Incentive motivation can be seen when a neutral stimulus acquires motivational properties through repeated association with a primary reinforcer. We compared adolescent (postnatal day (PND) 24-50) and adult (>PND 70) rats on a measure of incentive motivation: responding for a conditioned reinforcer (CR). Rats learned to associate the delivery of 0.1 ml of 10% sucrose with a conditioned stimulus (CS; light and tone); 30 pairings per day were given over 14 days. Then, we measured responding on a lever delivering the CS (now a CR) after injections of amphetamine (0, 0.25 or 0.5 mg/kg). We also examined responding for CR when the CS and sucrose were paired or unpaired during conditioning, and responding for the primary reinforcer (10% sucrose) in control experiments. Finally, we examined the effects of D(1) and D(2) dopamine receptor antagonists (SCH 39166 and eticlopride, respectively) and an opioid receptor antagonist (naltrexone) on responding for a CR in adolescent rats. Adolescents but not adults acquired responding for a CR, but adolescents responded less than adults for the primary reinforcer. Responding for a CR depended upon the pairing of the CS and sucrose during conditioning. Both dopamine and opioid receptor antagonists reduced responding for the CR. Therefore, incentive motivation may be enhanced in adolescents compared with adults, and incentive motivation may be mediated in part by both dopamine and opioid systems.
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857
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Saddoris MP, Stamatakis A, Carelli RM. Neural correlates of Pavlovian-to-instrumental transfer in the nucleus accumbens shell are selectively potentiated following cocaine self-administration. Eur J Neurosci 2011; 33:2274-87. [PMID: 21507084 PMCID: PMC3655808 DOI: 10.1111/j.1460-9568.2011.07683.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [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] [Indexed: 01/18/2023]
Abstract
During Pavlovian-to-instrumental transfer (PIT), learned Pavlovian cues significantly modulate ongoing instrumental actions. This phenomenon is suggested as a mechanism under which conditioned stimuli may lead to relapse in addicted populations. Following discriminative Pavlovian learning and instrumental conditioning with sucrose, one group of rats (naive) underwent electrophysiological recordings in the nucleus accumbens core and shell during a single PIT session. Other groups, following Pavlovian and instrumental conditioning, were subsequently trained to self-administer cocaine with nosepoke responses, or received yoked saline infusions and nosepoked for water rewards, and then performed PIT while electrophysiological recordings were taken in the nucleus accumbens. Behaviorally, although both naive and saline-treated groups showed increases in lever pressing during the conditioned stimulus cue, this effect was significantly enhanced in the cocaine-treated group. Neurons in the core and shell tracked these behavioral changes. In control animals, core neurons were significantly more likely to encode general information about cues, rewards and responses than those in the shell, and positively correlated with behavioral PIT performance, whereas PIT-specific encoding in the shell, but not core, tracked PIT performance. In contrast, following cocaine exposure, there was a significant increase in neural encoding of all task-relevant events that was selective to the shell. Given that cocaine exposure enhanced both behavior and shell-specific task encoding, these findings suggest that, whereas the core is important for acquiring the information about cues and response contingencies, the shell is important for using this information to guide and modulate behavior and is specifically affected following a history of cocaine self-administration.
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Affiliation(s)
- Michael P. Saddoris
- Department of Psychology, CB#3270 Davie Hall, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Alice Stamatakis
- Department of Psychology, CB#3270 Davie Hall, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Regina M. Carelli
- Department of Psychology, CB#3270 Davie Hall, University of North Carolina, Chapel Hill, NC 27599, USA
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
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858
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McCallum SE, Taraschenko OD, Hathaway ER, Vincent MY, Glick SD. Effects of 18-methoxycoronaridine on ghrelin-induced increases in sucrose intake and accumbal dopamine overflow in female rats. Psychopharmacology (Berl) 2011; 215:247-56. [PMID: 21210086 PMCID: PMC3790315 DOI: 10.1007/s00213-010-2132-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 12/01/2010] [Indexed: 11/28/2022]
Abstract
RATIONALE 18-methoxycoronaridine (18-MC), a selective antagonist of α3β4 nicotinic receptors, has been previously shown, in rats, to reduce the self-administration of several drugs of abuse, reduce operant responding for sucrose, and prevent the development of sucrose-induced obesity. It has become increasingly apparent that there is a significant overlap between the systems regulating drug reward and food intake, therefore, we investigated whether 18-MC might modulate the effects of ghrelin, one of several orexigenic peptides recently implicated in both feeding and drug reward. OBJECTIVES In female Sprague-Dawley rats, we determined whether acute 18-MC treatment would reduce both ghrelin-induced increases in sucrose intake and ghrelin-elicited increases in accumbal dopamine levels. RESULTS Pretreatment with 18-MC (20 mg/kg, i.p.), given prior to the administration of ghrelin (1 μg, lateral ventricle), blocked ghrelin-induced increases in sucrose (5%) intake in a two-bottle open access paradigm. Using in vivo microdialysis, 18-MC (both 20 and 40 mg/kg) prevented ghrelin (2 μg, intraventral tegmental area)-induced increases in extracellular dopamine in the nucleus accumbens. 18-MC had no effect on deposition of fat or on serum levels of glucose, triglycerides, and cholesterol in ghrelin-treated rats. CONCLUSIONS The present results suggest that one potential mechanism by which 18-MC exerts its effects on palatable food consumption is via modulation of ghrelin's effects.
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Affiliation(s)
- Sarah E McCallum
- Center for Neuropharmacology and Neuroscience MC-136, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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859
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Barclay AW, Brand-Miller J. The Australian paradox: a substantial decline in sugars intake over the same timeframe that overweight and obesity have increased. Nutrients 2011; 3:491-504. [PMID: 22254107 PMCID: PMC3257688 DOI: 10.3390/nu3040491] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [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: 03/04/2011] [Revised: 04/14/2011] [Accepted: 04/19/2011] [Indexed: 01/17/2023] Open
Abstract
Ecological research from the USA has demonstrated a positive relationship between sugars consumption and prevalence of obesity; however, the relationship in other nations is not well described. The aim of this study was to analyze the trends in obesity and sugar consumption in Australia over the past 30 years and to compare and contrast obesity trends and sugar consumption patterns in Australia with the UK and USA. Data on consumption of sugar in Australia, the UK and USA were obtained from the Food and Agriculture Organization for the years 1980-2003. The prevalence of obesity has increased 3 fold in Australians since 1980. In Australia, the UK and USA, per capita consumption of refined sucrose decreased by 23%, 10% and 20% respectively from 1980 to 2003. When all sources of nutritive sweeteners, including high fructose corn syrups, were considered, per capita consumption decreased in Australia (-16%) and the UK (-5%), but increased in the USA (+23%). In Australia, there was a reduction in sales of nutritively sweetened beverages by 64 million liters from 2002 to 2006 and a reduction in percentage of children consuming sugar-sweetened beverages between 1995 and 2007. The findings confirm an "Australian Paradox"--a substantial decline in refined sugars intake over the same timeframe that obesity has increased. The implication is that efforts to reduce sugar intake may reduce consumption but may not reduce the prevalence of obesity.
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Affiliation(s)
- Alan W. Barclay
- Australian Diabetes Council, 26 Arundel Street, Glebe, NSW 2037, Australia;
| | - Jennie Brand-Miller
- School of Molecular Bioscience and Boden Institute of Obesity, Nutrition and Exercise, University of Sydney, NSW 2006, Australia
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860
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Cottage A, Gray JC. Timing the switch to phototrophic growth: a possible role of GUN1. Plant Signal Behav 2011; 6:578-582. [PMID: 21673514 PMCID: PMC3142397 DOI: 10.4161/psb.6.4.14900] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [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: 01/20/2011] [Accepted: 01/20/2011] [Indexed: 05/29/2023]
Abstract
In young Arabidopsis seedlings, retrograde signalling from plastids regulates the expression of photosynthesis-associated nuclear genes in response to the developmental and functional state of the chloroplasts. The chloroplast-located PPR protein GUN1 is required for signalling following disruption of plastid protein synthesis early in seedling development before full photosynthetic competence has been achieved. Recently we showed that sucrose repression and the correct temporal expression of LHCB1, encoding a light-harvesting chlorophyll protein associated with photosystem II, are perturbed in gun1 mutant seedlings. ( 1) Additionally, we demonstrated that in gun1 seedlings anthocyanin accumulation and the expression of the "early" anthocyanin-biosynthesis genes is perturbed. Early seedling development, predominantly at the stage of hypocotyl elongation and cotyledon expansion, is also affected in gun1 seedlings in response to sucrose, ABA and disruption of plastid protein synthesis by lincomycin. These findings indicate a central role for GUN1 in plastid, sucrose and ABA signalling in early seedling development.
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Affiliation(s)
- Amanda Cottage
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
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861
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Campos-Soriano L, Segundo BS. New insights into the signaling pathways controlling defense gene expression in rice roots during the arbuscular mycorrhizal symbiosis. Plant Signal Behav 2011; 6:553-7. [PMID: 21422823 PMCID: PMC3142391 DOI: 10.4161/psb.6.4.14914] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [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: 01/24/2011] [Accepted: 01/24/2011] [Indexed: 05/05/2023]
Abstract
Mycorrhizal fungi form a mutualistic relationship with the roots of most plant species. This association provides the arbuscular mycorrhizal (AM) fungus with sugars while the fungus improves the uptake of water and mineral nutrients in the host plant. Moreover, the induction of defence gene expression in mycorrhizal roots has been described. While salicylic acid (SA)-regulated Pathogenesis-Related (PR) proteins accumulate in rice roots colonized by the AM fungus G. intraradices, the SA content is not significantly altered in the mycorrhizal roots. Sugars, in addition to being a source of carbon for the fungus, might act as signals for the control of defence gene expression. We hypothesize that increased demands for sugars by the fungus might be responsible for the activation of the host defence responses which will then contribute to the stabilization of root colonization by the AM fungus. An excessive root colonization might change a mutualistic association into a parasitic association.
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Affiliation(s)
- Lidia Campos-Soriano
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics, Barcelona, Spain
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862
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Abstract
Palatable food intake reduces stress responses, suggesting that individuals may consume such ?comfort? food as self-medication for stress relief. The mechanism by which palatable foods provide stress relief is not known, but likely lies at the intersection of forebrain reward and stress regulatory circuits. Forebrain opioidergic and gamma-aminobutyric acid ergic signaling is critical for both reward and stress regulation, suggesting that these systems are prime candidates for mediating stress relief by palatable foods. Thus, the present study (1) determines how palatable ?comfort? food alters stress-induced changes in the mRNA expression of inhibitory neurotransmitters in reward and stress neurocircuitry and (2) identifies candidate brain regions that may underlie comfort food-mediated stress reduction. We used a model of palatable ?snacking? in combination with a model of chronic variable stress followed by in situ hybridization to determine forebrain levels of pro-opioid and glutamic acid decarboxylase (GAD) mRNA. The data identify regions within the extended amygdala, striatum, and hypothalamus as potential regions for mediating hypothalamic-pituitary-adrenal axis buffering following palatable snacking. Specifically, palatable snacking alone decreased pro-enkephalin-A (ENK) mRNA expression in the anterior bed nucleus of the stria terminalis (BST) and the nucleus accumbens, and decreased GAD65 mRNA in the posterior BST. Chronic stress alone increased ENK mRNA in the hypothalamus, nucleus accumbens, amygdala, and hippocampus; increased dynorphin mRNA in the nucleus accumbens; increased GAD65 mRNA in the anterior hypothalamus and BST; and decreased GAD65 mRNA in the dorsal hypothalamus. Importantly, palatable food intake prevented stress-induced gene expression changes in subregions of the hypothalamus, BST, and nucleus accumbens. Overall, these data suggest that complex interactions exist between brain reward and stress pathways and that palatable snacking can mitigate many of the neurochemical alterations induced by chronic stress.
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Affiliation(s)
- A M Christiansen
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, 2170 E. Galbraith Road, Reading, OH 45237-0506, USA
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863
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Sahebihag MH, Hosseinzadeh M, Mohammadpourasl A, Kosha A. The study of Prevalence of Antigen HBs Positive and High-risk Behaviors in Pregnant Women Referring to Urban Health Centers of Isfahan Province in 2009. Iran J Nurs Midwifery Res 2011; 16:1-8. [PMID: 21772915 PMCID: PMC3127381] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 12/19/2009] [Indexed: 12/02/2022]
Abstract
BACKGROUND Around 5% of the world populations are the carriers of the hepatitis B virus. Prevalence of carriers in many different areas of the world is various. Iran, including the rate of 2 to 3%, is among countries, which has the average prevalence. The aim of this study was to determine the prevalence of antigen HBs positive and associated factors in pregnant women who had referred to urban health centers of Isfahan Province in 2009. METHODS A descriptive study conducted on 1078 pregnant women who had referred to the urban health centers of Isfahan, Barkhovar, Meymeh, Khomeini Shahr, Lenjan and Najaf Abad in 2009 in order to register their physical condition and conducting pregnancy care. Random sampling method by quota was systematic. First, a questionnaire completed including demographic characteristics and records of high-risk behaviors in mothers and wives. Then, 4 cc of their blood drawn and evaluated the antigen surface in serum. Finally, the data were analyzed using SPSS15 software, Chi-square, Fisher and Logistic Regression tests. RESULTS According to the findings, serum of 0.5% of pregnant women under the study was HBsAg-positive. The average age of subjects was 26.1 (4.9) years old and the average pregnancy number was 1.79 (1.0). Using Fisher's test as well as logistic regression test and based on the previous records of high-risk sexual behaviors and tattooing, a significant difference was observed in positive-HBsAg group in comparison with negative-HBsAg group (p ≤ 0.05). CONCLUSIONS Instructing target groups and giving awareness in large-scale, close monitoring in high-risk centers such as beauty shops, tattooing centers and etc, and also staff training in how to use disposable and sterilized equipments have to be accomplished at the right time.
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Affiliation(s)
- Mohammad Hasan Sahebihag
- MSc in Community Health Nursing, (PHD student) National Public Health Management Center (NPMC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mina Hosseinzadeh
- MSc in Community Health Nursing, Nursing & Midwifery Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.,
Correspondence to: Mina Hosseinzadeh,
| | - Asghar Mohammadpourasl
- MSc in Epidemiology, (PHD student), Health and Nutrition Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ahmad Kosha
- Assistant Professor, Health and Nutrition Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
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864
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Liu J, Vance CP. Crucial roles of sucrose and microRNA399 in systemic signaling of P deficiency: a tale of two team players? Plant Signal Behav 2010; 5:1556-60. [PMID: 21139425 PMCID: PMC3115102 DOI: 10.4161/psb.5.12.13293] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [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: 08/09/2010] [Accepted: 08/09/2010] [Indexed: 05/18/2023]
Abstract
MicroRNAs (miRNAs) have been recognized as important regulators in plant response to nutrient deficiencies. Of particular interest is the discovery that miR399 functions systemically in the maintenance of phosphate (Pi) homeostasis in response to external Pi fluctuation. Recent studies have further implicated both miR399 and sugars (mainly sucrose) as potential signal molecules in the shoot-to-root communication of phosphorus (P) status. Given that both miR399 and sucrose are transported via the phloem, their potential interaction (or cross-talk) along the signaling pathway is especially appealing for further exploration. In this mini-review, we highlight recent progress in unraveling crucial roles of both sucrose and miR399 in P-deficiency signaling. In particular, we further discuss recent findings that photosynthetic carbon (C) assimilation and subsequent partitioning, by overriding signaling of low external Pi, act as checkpoints upstream of miR399 for the onset of a systemic P-deficiency status.
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Affiliation(s)
- Junqi Liu
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, USA
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865
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Tonini PP, Purgatto E, Buckeridge MS. Effects of abscisic acid, ethylene and sugars on the mobilization of storage proteins and carbohydrates in seeds of the tropical tree Sesbania virgata (Leguminosae). Ann Bot 2010; 106:607-16. [PMID: 20705626 PMCID: PMC2944982 DOI: 10.1093/aob/mcq159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [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: 02/22/2010] [Revised: 06/08/2010] [Accepted: 07/01/2010] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Endospermic legumes are abundant in tropical forests and their establishment is closely related to the mobilization of cell-wall storage polysaccharides. Endosperm cells also store large numbers of protein bodies that play an important role as a nitrogen reserve in this seed. In this work, a systems approach was adopted to evaluate some of the changes in carbohydrates and hormones during the development of seedlings of the rain forest tree Sesbania virgata during the period of establishment. METHODS Seeds imbibed abscisic acid (ABA), glucose and sucrose in an atmosphere of ethylene, and the effects of these compounds on the protein contents, α-galactosidase activity and endogenous production of ABA and ethylene by the seeds were observed. KEY RESULTS The presence of exogenous ABA retarded the degradation of storage protein in the endosperm and decreased α-galactosidase activity in the same tissue during galactomannan degradation, suggesting that ABA represses enzyme action. On the other hand, exogenous ethylene increased α-galactosidase activity in both the endosperm and testa during galactomannan degradation, suggesting an inducing effect of this hormone on the hydrolytic enzymes. Furthermore, the detection of endogenous ABA and ethylene production during the period of storage mobilization and the changes observed in the production of these endogenous hormones in the presence of glucose and sucrose, suggested a correlation between the signalling pathway of these hormones and the sugars. CONCLUSIONS These findings suggest that ABA, ethylene and sugars play a role in the control of the hydrolytic enzyme activities in seeds of S. virgata, controlling the process of storage degradation. This is thought to ensure a balanced flow of the carbon and nitrogen for seedling development.
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Affiliation(s)
- Patricia Pinho Tonini
- University of São Paulo, Institute of Bioscience, Department of Botany, Postal Code 11461, São Paulo – SP, Brazil
| | - Eduardo Purgatto
- University of São Paulo, Faculty of Pharmaceutical Science, Department of Food and Experimental Nutrition, Postal Code 66083, São Paulo – SP, Brazil
| | - Marcos Silveira Buckeridge
- University of São Paulo, Institute of Bioscience, Department of Botany, Postal Code 11461, São Paulo – SP, Brazil
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866
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Anker JJ, Zlebnik NE, Carroll ME. Differential effects of allopregnanolone on the escalation of cocaine self-administration and sucrose intake in female rats. Psychopharmacology (Berl) 2010; 212:419-29. [PMID: 20689941 PMCID: PMC3773514 DOI: 10.1007/s00213-010-1968-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 07/17/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Evidence suggests that the progesterone metabolite allopregnanolone (ALLO) decreases cocaine seeking in animal models of relapse. OBJECTIVE The purpose of this study was to examine the effects of ALLO on an animal model of cocaine and sucrose bingeing (escalation). Allopregnanolone's effects on yohimbine-induced sucrose intake were also examined. In a separate group of animals, dose interactions between ALLO and cocaine were examined with an abbreviated procedure, a short access progressive ratio (PR) schedule for cocaine reinforcement. METHODS Female rats were treated with ALLO (15 mg/kg, s.c.) or vehicle (VEH) and trained to lever press for cocaine infusions (0.4 mg/kg) under an extended-access procedure. In a separate condition, other ALLO- and VEH-treated female rats self-administered orally delivered liquid sucrose. Allopregnanolone and VEH treatment was then discountinued and the sucrose-maintained rats were administered priming injections of saline, yohimbine, or yohimbine + ALLO. For the PR condition, rats were first treated with VEH until reaching stability at four doses of cocaine (0.2, 0.4, 0.8, and 1.6 mg/kg in mixed order). Subsequently, rats re-established their baseline cocaine intake at the four cocaine doses following treatment with each of two counterbalanced doses of ALLO (15 and 30 mg/kg). RESULTS ALLO significantly blocked the escalation of cocaine self-administration but did not reliably affect intake of sucrose under a similar condition or affect cocaine intake at several doses under a PR schedule. Yohimbine significantly increased sucrose intake while ALLO failed to attenuate this increase. CONCLUSION These findings indicate that ALLO protects against binge-like patterns of cocaine intake but does not reduce sugar intake that is acutely increased by yohimbine in females.
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Affiliation(s)
- Justin J. Anker
- Department of Psychiatry, University of Minnesota, MMC 392, Minneapolis, MN 55455, USA
| | - Natalie E. Zlebnik
- Department of Psychiatry, University of Minnesota, MMC 392, Minneapolis, MN 55455, USA
| | - Marilyn E. Carroll
- Department of Psychiatry, University of Minnesota, MMC 392, Minneapolis, MN 55455, USA
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867
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Hiyane R, Hiyane S, Tang AC, Boyer JS. Sucrose feeding reverses shade-induced kernel losses in maize. Ann Bot 2010; 106:395-403. [PMID: 20616114 PMCID: PMC2924829 DOI: 10.1093/aob/mcq132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [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: 03/19/2010] [Revised: 05/04/2010] [Accepted: 05/21/2010] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Water limitations can inhibit photosynthesis and change gene expression in ways that diminish or prevent reproductive development in plants. Sucrose fed to the plants can reverse the effects. To test whether the reversal acts generally by replacing the losses from photosynthesis, sucrose was fed to the stems of shaded maize plants (Zea mays) during reproductive development. METHODS Shading was adjusted to mimic the inhibition of photosynthesis around the time of pollination in water-limited plants. Glucose and starch were imaged and quantified in the female florets. Sucrose was infused into the stems to vary the sugar flux to the ovaries. KEY RESULTS Ovaries normally grew rapidly and contained large amounts of glucose and starch, with a glucose gradient favouring glucose movement into the developing ovary. Shade inhibited photosynthesis and diminished ovary and kernel size, weight, and glucose and starch contents compared with controls. The glucose gradient became small. Sucrose fed to the stem reversed these losses, and kernels were as large as the controls. CONCLUSIONS Despite similar inhibition of photosynthesis, the depletion of ovary glucose and starch was not as severe in shade as during a comparable water deficit. Ovary abortion prevalent during water deficits did not occur in the shade. It is suggested that this difference may have been caused by more translocation in shade than during the water deficit, which prevented low sugar contents necessary to trigger an up-regulation of senescence genes known to be involved in abortion. Nevertheless, sucrose feeding reversed kernel size losses and it is concluded that feeding acted generally to replace diminished photosynthetic activity.
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868
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Cottage A, Mott EK, Kempster JA, Gray JC. The Arabidopsis plastid-signalling mutant gun1 (genomes uncoupled1) shows altered sensitivity to sucrose and abscisic acid and alterations in early seedling development. J Exp Bot 2010; 61:3773-86. [PMID: 20605896 PMCID: PMC2921207 DOI: 10.1093/jxb/erq186] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 06/02/2010] [Accepted: 06/04/2010] [Indexed: 05/18/2023]
Abstract
Developing seedlings of the Arabidopsis gun1 (genomes uncoupled1) mutant, which is defective in retrograde plastid-to-nucleus signalling, show several previously unrecognized mutant phenotypes. gun1 seedlings accumulated less anthocyanin than wild-type seedlings when grown in the presence of 2% (w/v) sucrose, due to lower amounts of transcripts of early anthocyanin biosynthesis genes in gun1. Norflurazon and lincomycin, which induce retrograde signalling, further decreased the anthocyanin content of sucrose-treated seedlings, and altered the temporal pattern of anthocyanin accumulation. Lincomycin treatment altered the spatial pattern of sucrose-induced anthocyanin accumulation, suggesting that plastids provide information for the regulation of anthocyanin biosynthesis in Arabidopsis seedlings. The temporal pattern of accumulation of LHCB1 transcripts differed between wild-type and gun1 seedlings, and gun1 seedlings were more sensitive to sucrose suppression of LHCB1 transcript accumulation than wild-type seedlings. Growth and development of gun1 seedlings was more sensitive to exogenous 2% sucrose than wild-type seedlings and, in the presence of lincomycin, cotyledon expansion was enhanced in gun1 seedlings compared to the wild type. gun1 seedlings were more sensitive than wild-type seedlings to the inhibition of seedling growth and development by abscisic acid. These observations clearly implicate GUN1 and plastid signalling in the regulation of seedling development and anthocyanin biosynthesis, and indicate a complex interplay between sucrose and plastid signalling pathways.
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Affiliation(s)
| | | | | | - John C. Gray
- To whom correspondence should be addressed: E-mail:
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869
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Abstract
The epidemic of obesity and related metabolic diseases continues to extract an enormous health toll. Multiple potential causes for obesity have been suggested, including increased fat consumption, increased carbohydrate consumption, decreased physical activity, and, most recently, increased fructose consumption. Most literature cited in support of arguments suggesting a link between obesity and fructose consumption is epidemiologic and does not establish cause and effect. The causes of obesity are well-known and involve the overconsumption of calories from all sources. Research employing a pure fructose model distorts the real-world situation of fructose consumption, which predominantly comes from sweeteners containing roughly equal proportions of glucose and fructose. The fructose hypothesis has the potential to distract us from further exploration and amelioration of known causes of obesity. Randomized prospective trials of metabolic consequences of fructose consumption at normal population levels and from sources typically found in the human diet such as sucrose and high-fructose corn syrup are urgently needed.
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Affiliation(s)
- James M Rippe
- Rippe Lifestyle Institute, Shrewsbury, Massachusetts 01545, USA.
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870
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Mitra A, Gosnell BA, Schiöth HB, Grace MK, Klockars A, Olszewski PK, Levine AS. Chronic sugar intake dampens feeding-related activity of neurons synthesizing a satiety mediator, oxytocin. Peptides 2010; 31:1346-52. [PMID: 20399242 PMCID: PMC3175817 DOI: 10.1016/j.peptides.2010.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 04/06/2010] [Accepted: 04/07/2010] [Indexed: 01/08/2023]
Abstract
Increased tone of orexigens mediating reward occurs upon repeated consumption of sweet foods. Interestingly, some of these reward orexigens, such as opioids, diminish activity of neurons synthesizing oxytocin, a nonapeptide that promotes satiety and feeding termination. It is not known, however, whether consumption-related activity of the central oxytocin system is modified under chronic sugar feeding reward itself. Therefore, we examined how chronic consumption of a rewarding high-sucrose (HS) vs. bland cornstarch (CS) diet affected the activity of oxytocin cells in the hypothalamus at the time of meal termination. Schedule-fed (2h/day) rats received either a HS or CS powdered diet for 20 days. On the 21st day, they were given the same or the opposite diet, and food was removed after the main consummatory activity was completed. Animals were perfused 60 min after feeding termination and brains were immunostained for oxytocin and the marker of neuronal activity, c-Fos. The percentage of c-Fos-positive oxytocin cells in the hypothalamic paraventricular nucleus was significantly lower in rats chronically exposed to the HS than to the CS diet, regardless of which diet they received on the final day. A similar pattern was observed in the supraoptic nucleus. We conclude that the chronic rather than acute sucrose intake reduces activity of the anorexigenic oxytocin system. These findings indicate that chronic consumption of sugar blunts activity of pathways that mediate satiety. We speculate that a reduction in central satiety signaling precipitated by regular intake of foods high in sugar may lead to generalized overeating.
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Affiliation(s)
- Anaya Mitra
- Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA.
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871
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Merchant A, Peuke AD, Keitel C, Macfarlane C, Warren CR, Adams MA. Phloem sap and leaf delta13C, carbohydrates, and amino acid concentrations in Eucalyptus globulus change systematically according to flooding and water deficit treatment. J Exp Bot 2010; 61:1785-93. [PMID: 20211969 PMCID: PMC2852667 DOI: 10.1093/jxb/erq045] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [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: 11/06/2009] [Revised: 01/28/2010] [Accepted: 02/12/2010] [Indexed: 05/18/2023]
Abstract
Phloem is a central conduit for the distribution of photoassimilate, nutrients, and signals among plant organs. A revised technique was used to collect phloem sap from small woody plants in order to assess changes in composition induced by water deficit and flooding. Bled phloem sap delta(13)C and sugar concentrations were compared to delta(13)C of bulk material, soluble carbon extracts, and the neutral sugar fraction from leaves. Amino acid composition and inorganic ions of the phloem sap was also analysed. Quantitative, systematic changes were detected in phloem sap composition and delta(13)C in response to altered water availability. Phloem sap delta(13)C was more sensitive to changes of water availability than the delta(13)C of bulk leaf, the soluble carbon fraction, and the neutral soluble fraction of leaves. Changes in water availability also resulted in significant changes in phloem sugar (sucrose and raffinose), inorganic nutrient (potassium), and amino acid (phenylalanine) concentrations with important implications for the maintenance of phloem function and biomass partitioning. The differences in carbohydrate and amino acid composition as well as the delta(13)C in the phloem, along with a new model system for phloem research, offer an improved understanding of the phloem-mediated signal, nutrient, and photoassimilate transduction in relation to water availability.
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Affiliation(s)
- Andrew Merchant
- School of Biological, Earth and Environmental Science University of New South Wales, Sydney NSW, Australia 2052.
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872
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Poiré R, Wiese-Klinkenberg A, Parent B, Mielewczik M, Schurr U, Tardieu F, Walter A. Diel time-courses of leaf growth in monocot and dicot species: endogenous rhythms and temperature effects. J Exp Bot 2010; 61:1751-9. [PMID: 20299442 PMCID: PMC2852670 DOI: 10.1093/jxb/erq049] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [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: 10/01/2009] [Revised: 02/07/2010] [Accepted: 02/08/2010] [Indexed: 05/18/2023]
Abstract
Diel (24 h) leaf growth patterns were differently affected by temperature variations and the circadian clock in several plant species. In the monocotyledon Zea mays, leaf elongation rate closely followed changes in temperature. In the dicotyledons Nicotiana tabacum, Ricinus communis, and Flaveria bidentis, the effect of temperature regimes was less obvious and leaf growth exhibited a clear circadian oscillation. These differences were related neither to primary metabolism nor to altered carbohydrate availability for growth. The effect of endogenous rhythms on leaf growth was analysed under continuous light in Arabidopsis thaliana, Ricinus communis, Zea mays, and Oryza sativa. No rhythmic growth was observed under continuous light in the two monocotyledons, while growth rhythmicity persisted in the two dicotyledons. Based on model simulations it is concluded that diel leaf growth patterns in mono- and dicotyledons result from the additive effects of both circadian-clock-controlled processes and responses to environmental changes such as temperature and evaporative demand. Apparently very distinct diel leaf growth behaviour of monocotyledons and dicotyledons can thus be explained by the different degrees to which diel temperature variations affect leaf growth in the two groups of species which, in turn, depends on the extent of the leaf growth control by internal clocks.
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Affiliation(s)
- Richard Poiré
- ICG-3 (Phytosphere), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | | | - Boris Parent
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, F-34060 Montpellier, France
| | - Michael Mielewczik
- ICG-3 (Phytosphere), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Ulrich Schurr
- ICG-3 (Phytosphere), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - François Tardieu
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, F-34060 Montpellier, France
| | - Achim Walter
- ICG-3 (Phytosphere), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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873
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Ebner SR, Roitman MF, Potter DN, Rachlin AB, Chartoff EH. Depressive-like effects of the kappa opioid receptor agonist salvinorin A are associated with decreased phasic dopamine release in the nucleus accumbens. Psychopharmacology (Berl) 2010; 210:241-52. [PMID: 20372879 PMCID: PMC2894632 DOI: 10.1007/s00213-010-1836-5] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 03/11/2010] [Indexed: 11/25/2022]
Abstract
RATIONALE Kappa opioid receptors (KORs) have been implicated in depressive-like states associated with chronic administration of drugs of abuse and stress. Although KOR agonists decrease dopamine in the nucleus accumbens (NAc), KOR modulation of phasic dopamine release in the core and shell subregions of the NAc-which have distinct roles in reward processing-remains poorly understood. OBJECTIVES Studies were designed to examine whether the time course of effects of KOR activation on phasic dopamine release in the NAc core or shell are similar to effects on motivated behavior. METHODS The effect of systemic administration of the KOR agonist salvinorin A (salvA)-at a dose (2.0 mg/kg) previously determined to have depressive-like effects-was measured on electrically evoked phasic dopamine release in the NAc core or shell of awake and behaving rats using fast scan cyclic voltammetry. In parallel, the effects of salvA on intracranial self-stimulation (ICSS) and sucrose-reinforced responding were assessed. For comparison, a threshold dose of salvA (0.25 mg/kg) was also tested. RESULTS The active, but not threshold, dose of salvA significantly decreased phasic dopamine release without affecting dopamine reuptake in the NAc core and shell. SalvA increased ICSS thresholds and significantly lowered breakpoint on the progressive ratio schedule, indicating a decrease in motivation. The time course of the KOR-mediated decrease in dopamine in the core was qualitatively similar to the effects on motivated behavior. CONCLUSIONS These data suggest that the effects of KOR activation on motivation are due, in part, to inhibition of phasic dopamine signaling in the NAc core.
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Affiliation(s)
- Stephanie R Ebner
- Department of Psychology, University of Illinois at Chicago, Chicago, IL 60607, USA
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874
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Abstract
Preterm and critically ill newborns admitted to a NICU undergo repeated skin-breaking procedures that are necessary for their survival. Sucrose is rapidly becoming the accepted clinical standard nonpharmacologic intervention for managing acute procedural pain for these infants. Although shown to be safe in single doses, only 4 studies have evaluated the effects of repeated doses of sucrose over relatively short periods of time. None has examined the use of sucrose throughout the NICU stay, and only 1 study evaluated the neurodevelopmental outcomes after repeated doses of sucrose. In that study, infants born at <31 weeks' gestational age and exposed to >10 doses per day in the first week of life were more likely to show poorer attention and motor development in the early months after discharge from the NICU. Results of studies in animal models have suggested that the mechanism of action of sucrose is through opioid pathways; however, in human infants, little has been done to examine the physiologic mechanisms involved, and the findings reported thus far have been ambiguous. Drawing from the growing animal literature of research that has examined the effects of chronic sugar exposure, we describe alternative amine and hormone pathways that are common to the processing of sucrose, attention, and motor development. In addition, a review of the latest research to examine the effects of repeated sucrose on pain processing is presented. These 2 literatures each can inform the other and can provide an impetus to initiate research to examine not only the mechanisms involved in the calming mechanisms of sucrose but also in the long-term neurodevelopmental effects of repeated sucrose in those infants born extremely preterm or critically ill.
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Affiliation(s)
- Liisa Holsti
- Developmental Neurosciences and Child Health, Child and Family Research Institute, Vancouver, British Columbia, Canada.
| | - Ruth E. Grunau
- Developmental Neurosciences and Child Health, Child and Family Research Institute, Vancouver, British Columbia, Canada, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
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875
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Wild B, Wanek W, Postl W, Richter A. Contribution of carbon fixed by Rubisco and PEPC to phloem export in the Crassulacean acid metabolism plant Kalanchoe daigremontiana. J Exp Bot 2010; 61:1375-83. [PMID: 20159885 PMCID: PMC2837257 DOI: 10.1093/jxb/erq006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [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: 10/23/2009] [Revised: 12/23/2009] [Accepted: 01/04/2010] [Indexed: 05/21/2023]
Abstract
Crassulacean acid metabolism (CAM) plants exhibit a complex interplay between CO(2) fixation by phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), and carbon demand for CAM maintenance and growth. This study investigated the flux of carbon from PEPC and direct Rubisco fixation to different leaf carbon pools and to phloem sap over the diurnal cycle. Concentrations and carbon isotope compositions of starch, soluble sugars, and organic acids were determined in leaves and phloem exudates of Kalanchoë daigremontiana Hamet et Perr., and related to CO(2) fixation by PEPC and Rubisco. Three types of leaf carbon pools could be distinguished. (i) Starch and malate pools were dominant and showed a pattern of reciprocal mobilization and accumulation (85/54 and 13/48 mg C g(-1) DW, respective, at the beginning/end of phase I). The carbon isotope composition of these pools was compatible with predominant PEPC fixation (delta(13)C values of -13 and -11 per thousand for starch and malate compared to -11 per thousand of PEPC fixed carbon). (ii) Isotopic composition (-17 per thousand and -14 per thousand) and concentration of glucose and fructose (2 and 3 mg C g(-1) DW, respectively) were not affected by diurnal metabolism, suggesting a low turnover. (iii) Sucrose (1-3 mg C g(-1) DW), in contrast, exhibited large diurnal changes in delta(13)C values (from -17 per thousand in the evening to -12 per thousand in the morning), which were not matched by net changes in sucrose concentration. This suggests a high sucrose turnover, fed by nocturnal starch degradation and direct Rubisco fixation during the day. A detailed dissection of the carbon fixation and mobilization pattern in K. daigremontiana revealed that direct fixation of Rubisco during the light accounted for 30% of phloem sucrose, but only 15% of fixed carbon, indicating that carbon from direct Rubisco fixation was preferentially used for leaf export.
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Affiliation(s)
- Birgit Wild
- Department of Chemical Ecology and Ecosystem Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
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876
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McOmber ME, Ou CN, Shulman RJ. Effects of timing, sex, and age on site-specific gastrointestinal permeability testing in children and adults. J Pediatr Gastroenterol Nutr 2010; 50:269-75. [PMID: 20081547 DOI: 10.1097/MPG.0b013e3181aa3aa9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Measurement of gastrointestinal (GI) permeability is commonly used in research and often used clinically. Despite its utility, little is known about sugar excretion timeframes or the potential effects of age and sex on GI permeability testing. We seek to determine the timeframes of sugar excretion and the potential effects of age and sex on urinary recovery of the sugars. SUBJECTS AND METHODS Healthy adults (n = 17) and children (n = 15) fasted 4 hours after the evening meal and then ingested a solution of sucrose, lactulose, mannitol, and sucralose. Urine was collected at 30, 60, and 90 minutes after ingestion and then each time the subjects voided during the next 24 hours. Each urine void was collected separately. RESULTS Median age for the adults was 47.5 years (range 21-57 years) and for children 10 years (range 5-17 years). There were no differences between children and adults in mean percent dose of sugar recovered. The time of peak urinary recovery of the sugars was generally similar between children and adults. Sucrose urinary recovery declined with age (P = 0.008; r2 = 0.19) unrelated to sex. Lactulose and sucralose urinary recovery declined with age in females (P = 0.05, r2 = 0.24 and P = 0.011, r2 = 0.41; respectively) but not in males. CONCLUSIONS Overall, sugar urinary recovery is comparable in children and adults. Specific sugar urinary recovery may change as a function of age and/or sex. These results need to be taken into account when planning and interpreting gastrointestinal permeability studies.
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877
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Chau DT, Gulick D, Xie H, Dawson R, Green AI. Clozapine chronically suppresses alcohol drinking in Syrian golden hamsters. Neuropharmacology 2010; 58:351-6. [PMID: 19895824 PMCID: PMC4427519 DOI: 10.1016/j.neuropharm.2009.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [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: 08/14/2009] [Revised: 10/21/2009] [Accepted: 10/23/2009] [Indexed: 11/30/2022]
Abstract
Alcohol use disorder is common in patients with schizophrenia and is associated with poor clinical outcomes. Preliminary reports from our group and others suggest that the atypical antipsychotic clozapine may decrease alcohol use in these patients. We have previously shown that clozapine suppresses alcohol consumption for 9 days in Syrian golden hamsters. Here, we assessed the effects of clozapine on alcohol consumption in hamsters over a 27-day period, using a continuous access, 2-bottle (15% alcohol vs. water) protocol. Clozapine (4, 8, or 12 mg/kg/day, injected subcutaneously [s.c.]) dose-dependently suppressed alcohol drinking, while increasing food and water intake. There was no tolerance within individual groups to the effect of clozapine on alcohol drinking over time. In a separate experiment, the effects of clozapine on sucrose and water drinking and food intake over a 9-day period were assessed. Clozapine (4, 8, or 12 mg/kg/day s.c.) failed to suppress sucrose (0.09 M), food, or water consumption at any time-point tested. In a related study, assessment of blood alcohol levels in hamsters indicated that blood alcohol levels were maintained within a narrow and moderate range (7-13 mg/dL), levels noted by others to produce physiologic effects in rodents. The ability of clozapine to suppress alcohol drinking in the hamster over an extended period of time without suppressing sucrose, water, or food consumption is consistent with preliminary reports indicating that clozapine limits frequent alcohol use, even producing abstinence in many patients with schizophrenia.
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Affiliation(s)
- David T. Chau
- Department of Psychiatry, Dartmouth Medical School, One Medical Center Drive, Lebanon, NH 03756, USA
| | - Danielle Gulick
- Department of Psychiatry, Dartmouth Medical School, One Medical Center Drive, Lebanon, NH 03756, USA
| | - Haiyi Xie
- Department of Psychiatry, Dartmouth Medical School, One Medical Center Drive, Lebanon, NH 03756, USA
- Department of Community and Family Medicine, USA
| | - Ree Dawson
- Frontier Science and Technology Research Foundation, USA
| | - Alan I. Green
- Department of Psychiatry, Dartmouth Medical School, One Medical Center Drive, Lebanon, NH 03756, USA
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878
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Sánchez-Lozada LG, Mu W, Roncal C, Sautin YY, Abdelmalek M, Reungjui S, Le M, Nakagawa T, Lan HY, Yu X, Johnson RJ. Comparison of free fructose and glucose to sucrose in the ability to cause fatty liver. Eur J Nutr 2010; 49:1-9. [PMID: 19626358 PMCID: PMC2805058 DOI: 10.1007/s00394-009-0042-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [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: 02/10/2009] [Accepted: 07/05/2009] [Indexed: 12/14/2022]
Abstract
BACKGROUND There is evidence that disaccharide sucrose produce a greater increase in serum fructose and triglycerides (TGs) than the effect produced by their equivalent monosaccharides, suggesting that long-term exposure to sucrose or fructose + glucose could potentially result in different effects. AIM OF THE STUDY We studied the chronic effects of a combination of free fructose and glucose relative to sucrose on rat liver. METHODS Rats were fed either a combination of 30% fructose and 30% glucose (FG) or 60% sucrose (S). Control rats were fed normal rat chow (C). All rats were pair fed and were followed for 4 months. After killing, blood chemistries and liver tissue were examined. RESULTS Both FG-fed- and S-fed rats developed early features of metabolic syndrome when compared with C. In addition, both diets induced hepatic alterations, including variable increases in hepatic TG accumulation and fatty liver, an increase in uric acid content in the liver, as well as an increase in hepatic levels of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) measured in liver homogenates. CONCLUSIONS Diets containing 30% of fructose either as free fructose and glucose, or as sucrose, induce metabolic syndrome, intrahepatic accumulation of uric acid and TGs, increased MCP-1 and TNF-alpha as well as fatty liver in rats. It will be relevant to determine clinically whether pharmacological reduction in uric acid levels might have a therapeutic advantage in the treatment of non-alcoholic fatty liver disease.
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Affiliation(s)
- Laura G Sánchez-Lozada
- Division of Nephrology, Hypertension and Transplantation, University of Florida, Gainesville, FL, USA.
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879
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van der Merwe MJ, Groenewald JH, Stitt M, Kossmann J, Botha FC. Downregulation of pyrophosphate: D-fructose-6-phosphate 1-phosphotransferase activity in sugarcane culms enhances sucrose accumulation due to elevated hexose-phosphate levels. Planta 2010; 231:595-608. [PMID: 19957089 PMCID: PMC2806535 DOI: 10.1007/s00425-009-1069-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [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: 09/01/2009] [Accepted: 11/09/2009] [Indexed: 05/19/2023]
Abstract
Analyses of transgenic sugarcane clones with 45-95% reduced cytosolic pyrophosphate: D-fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) activity displayed no visual phenotypical change, but significant changes were evident in in vivo metabolite levels and fluxes during internode development. In three independent transgenic lines, sucrose concentrations increased between three- and sixfold in immature internodes, compared to the levels in the wildtype control. There was an eightfold increase in the hexose-phosphate:triose-phosphate ratio in immature internodes, a significant restriction in the triose phosphate to hexose phosphate cycle and significant increase in sucrose cycling as monitored by (13)C nuclear magnetic resonance. This suggests that an increase in the hexose-phosphate concentrations resulting from a restriction in the conversion of hexose phosphates to triose phosphates drive sucrose synthesis in the young internodes. These effects became less pronounced as the tissue matured. Decreased expression of PFP also resulted in an increase of the ATP/ADP and UTP/UDP ratios, and an increase of the total uridine nucleotide and, at a later stage, the total adenine nucleotide pool, revealing strong interactions between PPi metabolism and general energy metabolism. Finally, decreased PFP leads to a reduction of PPi levels in older internodes indicating that in these developmental stages PFP acts in the gluconeogenic direction. The lowered PPi levels might also contribute to the absence of increases in sucrose contents in the more mature tissues of transgenic sugarcane with reduced PFP activity.
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Affiliation(s)
- Margaretha J van der Merwe
- Institute of Plant Biotechnology, University of Stellenbosch, Merriman Avenue, Stellenbosch 7602, South Africa.
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880
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Ritsema T, Peppelenbosch MP. Kinome profiling of sugar signaling in plants using multiple platforms. Plant Signal Behav 2009; 4:1169-73. [PMID: 20514238 PMCID: PMC2819448 DOI: 10.4161/psb.4.12.10022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 04/09/2009] [Indexed: 05/08/2023]
Abstract
Although the primary sequence of kinases shows substantial divergence between unrelated eukaryotes, variation in the motifs that are actually phosphorylated by eukaryotic kinases is much smaller. Hence arrays developed for kinome profiling of mammalian cells are useful for kinome profiling of plant tissues as well, facilitating the study of plant signal transduction. We recently employed the Pepscan kinomics chip to reveal the small GTPases in plant sucrose signaling. Here we show that employing a different peptide library (the Pepscan kinase chip) largely similar results are obtained, confirming these earlier data, but such a different library also contributes new insights into the molecular details mediating plant cell responses to a sugar stimulus. Thus when studying plant signal transduction employing peptide arrays, using multiple platforms both increases the confidence of results and provides additional information.
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Affiliation(s)
- Tita Ritsema
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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881
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Ramel F, Sulmon C, Gouesbet G, Couée I. Natural variation reveals relationships between pre-stress carbohydrate nutritional status and subsequent responses to xenobiotic and oxidative stress in Arabidopsis thaliana. Ann Bot 2009; 104:1323-37. [PMID: 19789177 PMCID: PMC2778391 DOI: 10.1093/aob/mcp243] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [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: 06/26/2009] [Revised: 07/23/2009] [Accepted: 08/21/2009] [Indexed: 05/20/2023]
Abstract
BACKGROUND Soluble sugars are involved in responses to stress, and act as signalling molecules that activate specific or hormone cross-talk transduction pathways. Thus, exogenous sucrose treatment efficiently induces tolerance to the herbicide atrazine in Arabidopsis thaliana plantlets, at least partially through large-scale modifications of expression of stress-related genes. METHODS Availability of sugars in planta for stress responses is likely to depend on complex dynamics of soluble sugar accumulation, sucrose-starch partition and organ allocation. The question of potential relationships between endogenous sugar levels and stress responses to atrazine treatment was investigated through analysis of natural genetic accessions of A. thaliana. Parallel quantitative and statistical analysis of biochemical parameters and of stress-sensitive physiological traits was carried out on a set of 11 accessions. KEY RESULTS Important natural variation was found between accessions of A. thaliana in pre-stress shoot endogenous sugar levels and responses of plantlets to subsequent atrazine stress. Moreover, consistent trends and statistically significant correlations were detected between specific endogenous sugar parameters, such as the pre-stress end of day sucrose level in shoots, and physiological markers of atrazine tolerance. CONCLUSIONS These significant relationships between endogenous carbohydrate metabolism and stress response therefore point to an important integration of carbon nutritional status and induction of stress tolerance in plants. The specific correlation between pre-stress sucrose level and greater atrazine tolerance may reflect adaptive mechanisms that link sucrose accumulation, photosynthesis-related stress and sucrose induction of stress defences.
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882
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Abstract
Rubber tree (Hevea brasiliensis) is an important industrial crop for natural rubber production. Ethylene, as a stimulant of latex production in H. brasiliensis, has been widely used in commercial latex production. However, the mechanism of ethylene action are not completely elucidated, especially in molecular aspect. Here, we focus on the molecular biological progression of ethylene stimulation of latex production. Our data and all previous information showed ethylene had little direct effect on accelerating rubber biosynthesis. The prolonged latex flow and acceleration of sucrose metabolism by ethylene may be the main reasons for the stimulation of latex yield by ethylene.
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Affiliation(s)
- Jiahong Zhu
- Key Laboratory of Tropical Crop Biotechnology; Ministry of Agriculture; Institute of Tropical Biosciences and Biotechnology; Chinese Academy of Tropical Agricultural Sciences; Haikou, China
| | - Zhili Zhang
- Key Laboratory of Tropical Crop Biotechnology; Ministry of Agriculture; Institute of Tropical Biosciences and Biotechnology; Chinese Academy of Tropical Agricultural Sciences; Haikou, China
- Hainan Academy of Agricultural Sciences; Haikou, China
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883
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Srivastava AC, Dasgupta K, Ajieren E, Costilla G, McGarry RC, Ayre BG. Arabidopsis plants harbouring a mutation in AtSUC2, encoding the predominant sucrose/proton symporter necessary for efficient phloem transport, are able to complete their life cycle and produce viable seed. Ann Bot 2009; 104:1121-8. [PMID: 19789176 PMCID: PMC2766205 DOI: 10.1093/aob/mcp215] [Citation(s) in RCA: 19] [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] [Received: 06/18/2009] [Revised: 07/21/2009] [Accepted: 07/23/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS AtSUC2 encodes a sucrose/proton symporter that localizes throughout the collection and transport phloem and is necessary for efficient transport of sucrose from source to sink tissues in Arabidopsis thaliana. Plants harbouring homozygous AtSUC2 null alleles accumulate sugar, starch, and anthocyanin in mature leaves, have severely delayed development and stunted growth and, in previous studies, failed to complete their life cycle by producing viable seed. METHODS An AtSUC2 allele with a T-DNA insertion in the second intron was analysed. Full-length transcript from this allele is not produced, and a truncated protein translated from sequences upstream of the insertion site did not catalyse sucrose uptake into yeast, supporting the contention that this is a null allele. Mutant plants were grown in a growth chamber with a diurnal light/dark cycle, and growth patterns recorded. KEY RESULTS This allele (SALK_038124, designated AtSUC2-4) has the hallmarks of previously described null alleles but, despite compromised carbon partitioning and growth, produces viable seeds. The onset of flowering was chronologically delayed but occurred at the same point in the plastochron index as wild type. CONCLUSIONS AtSUC2 is important for phloem loading and is therefore fundamental to phloem transport and plant productivity, but plants can complete their life cycle and produce viable seed in its absence. Arabidopsis appears to have mechanisms for mobilizing reduced carbon from the phloem into developing seeds independent of AtSUC2.
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Affiliation(s)
| | | | | | | | | | - Brian G. Ayre
- University of North Texas, Department of Biological Sciences, 1155 Union Circle #305220, Denton TX 76203-5017, USA
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884
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Abstract
D-Psicose is a rare sugar present in small quantities in natural products. In a previous study, we showed that D-psicose suppresses plasma glucose increases and reduces body fat accumulation in rats. Based on acute toxicity testing in rats, D-psicose is classified as an ordinary substance (LD(50) = 16 g/kg). Elucidating the effects of long term feeding of D-psicose in rats will be essential prior to its utilization as a physiologically functional food. In this study, male Wistar rats (3 weeks old) were fed diets containing 3% D-psicose or sucrose for 12-18 months. The rats actually ingested 1.28 g/kg body weight per day D-psicose or 1.22 g/kg body weight per day of sucrose. Body weight gain and intra-abdominal adipose tissue weight in rats fed the D-psicose diet for 18 months were significantly lower than those in rats fed the sucrose diet. Relative weights of liver and kidney were significantly higher in the D-psicose group than in the sucrose group. However, no gross pathological findings were evident at dietary doses of 3% D-psicose or correlated with hypertrophy of liver and kidney. No clinical chemical test value was suggestive of overt D-psicose treatment-related toxicity. Therefore, the present study found no adverse effects at 3% D-psicose in the diet.
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Affiliation(s)
- Kanako Yagi
- Faculty of Agriculture, Kagawa University, Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan
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885
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Fudge MA, Kavaliers M, Baird JP, Ossenkopp KP. Tamoxifen produces conditioned taste avoidance in male rats: an analysis of microstructural licking patterns and taste reactivity. Horm Behav 2009; 56:322-31. [PMID: 19576896 PMCID: PMC2747617 DOI: 10.1016/j.yhbeh.2009.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 06/05/2009] [Accepted: 06/23/2009] [Indexed: 11/16/2022]
Abstract
Estrogen receptor activation has been shown to reduce body weight and produce a conditioned reduction in food intake in male rats that is putatively mediated by estradiol's suggested aversive effects. Evidence has shown that the selective estrogen receptor modulator tamoxifen used in the prevention and treatment of breast cancer may also produce changes in food intake and body weight, which are known to impact cancer development and survival. The purpose of the present study was to examine whether tamoxifen produces a conditioned reduction in intake similar to estradiol by producing a conditioned aversion. A one bottle lickometer test was used to examine conditioned changes in sucrose drinking, while the taste reactivity test was used to measure rejection reactions, which serve to index aversion in rats. A backward conditioning procedure that consisted of 3 conditioning days and one vehicle test day was used to examine conditioned changes in 0.3 M sucrose intake and taste reactivity. Our results show that tamoxifen produced a conditioned reduction in sucrose drinking in a one bottle fluid intake test that was similar to the effects produced by estradiol (positive control); however, no active rejection reactions were produced by either tamoxifen (1 and 10 mg/kg) or estradiol. The present results suggest that tamoxifen, at the doses used in the present study, acts as an estrogen receptor agonist to regulate food intake and that the conditioned reduction in intake produced by tamoxifen and estradiol reflects conditioned taste avoidance rather than conditioned taste aversion.
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Affiliation(s)
- Melissa A Fudge
- Department of Psychology, The University of Western Ontario, London, Ontario, Canada.
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886
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Rosa M, Prado C, Podazza G, Interdonato R, González JA, Hilal M, Prado FE. Soluble sugars--metabolism, sensing and abiotic stress: a complex network in the life of plants. Plant Signal Behav 2009; 4:388-93. [PMID: 19816104 PMCID: PMC2676748 DOI: 10.4161/psb.4.5.8294] [Citation(s) in RCA: 402] [Impact Index Per Article: 26.8] [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: 02/19/2009] [Accepted: 02/26/2009] [Indexed: 05/18/2023]
Abstract
Plants are autotrophic and photosynthetic organisms that both produce and consume sugars. Soluble sugars are highly sensitive to environmental stresses, which act on the supply of carbohydrates from source organs to sink ones. Sucrose and hexoses both play dual functions in gene regulation as exemplified by the upregulation of growth-related genes and downregulation of stress-related genes. Although coordinately regulated by sugars, these growth- and stress-related genes are upregulated or downregulated through HXK-dependent and/or HXK-independent pathways. Sucrose-non-fermenting-1- (SNF1-) related protein pathway, analogue to the protein kinase (SNF-) yeast-signalling pathway, seems also involved in sugar sensing and transduction in plants. However, even if plants share with yeast some elements involved in sugar sensing, several aspects of sugar perception are likely to be peculiar to higher plants. In this paper, we have reviewed recent evidences how plants sense and respond to environmental factors through sugar-sensing mechanisms. However, we think that forward and reverse genetic analysis in combination with expression profiling must be continued to uncover many signalling components, and a full biochemical characterization of the signalling complexes will be required to determine specificity and cross-talk in abiotic stress signalling pathways.
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Affiliation(s)
- Mariana Rosa
- Facultad de Ciencias Naturales e IML, Tucumán, Argentina
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887
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Abbes Z, Kharrat M, Delavault P, Chaïbi W, Simier P. Osmoregulation and nutritional relationships between Orobanche foetida and faba bean. Plant Signal Behav 2009; 4:336-338. [PMID: 19794856 PMCID: PMC2664500 DOI: 10.4161/psb.4.4.8192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 02/16/2009] [Indexed: 05/28/2023]
Abstract
The present study aims at comparing the phloem composition of the tolerant XBJ90.03-16-1-1-1 and the susceptible Bachaar genotypes and the impact of the faba bean genotype on the levels of the major solutes and invertase activities in the parasite Orobanche foetida. In comparison to Bachaar, the XBJ90.03-161-1-1 genotype limited the growth of orobanche tubercles under in vitro conditions. The limited growth was due to low soluble invertase activity, low osmotic potential of the infected roots and the organic nitrogen deficiency of the host phloem sap. The faba bean genotype did not affect the osmoregulation process of O. foetida. Among the organic solutes, stachyose, hexoses, starch and free amino acids, mainly asparagine and aspartate were highly accumulated in orobanche. However, asparagine/aspartate, glutamine/glutamate, alanine, serine, gamma amino butyric acid, stachyose, sucrose were identified as the main organic components in the host phloem exudates. The key role of the enzymes α-galactosidase, asparagine synthetase and aspartate oxaloglutarate aminotransferase in the utilization of the host solutes is proposed in O. foetida parasitizing faba bean.
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Affiliation(s)
- Zouhaier Abbes
- INRAT, Laboratoire des Grandes Cultures, Ariana, Tunisia.
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888
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Ceusters J, Borland AM, De Proft MP. Drought adaptation in plants with crassulacean acid metabolism involves the flexible use of different storage carbohydrate pools. Plant Signal Behav 2009; 4:212-4. [PMID: 19721752 PMCID: PMC2652531 DOI: 10.4161/psb.4.3.7813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 05/09/2023]
Abstract
Nocturnal CO2 uptake in CAM plants is sustained by the degradation of storage carbohydrate which provides the acceptor (PEP) for the nocturnal carboxylase (PEPC). The investment of resources into a transient storage carbohydrate pool unavoidably places restriction on other metabolic activities including dark respiration, growth and acclimation to abiotic stress. In our recent report the flexible use of different storage carbohydrate pools is shown to be involved in the acclimation process to drought and recovery from dehydration. While starch breakdown stoichiometrically accounts for nocturnal CO2 uptake under well-watered conditions, the sucrose pool is maintained in preference to starch during progressing drought and sucrose becomes the major source of carbon fuelling the dark reactions after 45 days of water deprivation. Re-watering plants results in a recovery to the original situation, with starch constituting the main carbohydrate reserve for nocturnal provision of PEP. However, substantial amounts of starch are also retained in the leaves of re-watered plants by restricting export/respiration and thus provides a potential buffer capacity against a return to water deprivation. This significant conservation of starch suggests the ability to perceive, remember and anticipate the formerly encountered drought stress in some way, with the adaptation of the equilibrium of carbohydrate balance as a central factor underpinning the physiological homeostasis of CAM plants.
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Affiliation(s)
- Johan Ceusters
- Faculty of Bioscience Engineering, Department of Biosystems, Division of Crop Biotechnics, Katholieke Universiteit Leuven, Heverlee, Belgium.
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889
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Lawlor DW, Tezara W. Causes of decreased photosynthetic rate and metabolic capacity in water-deficient leaf cells: a critical evaluation of mechanisms and integration of processes. Ann Bot 2009; 103:561-79. [PMID: 19155221 PMCID: PMC2707350 DOI: 10.1093/aob/mcn244] [Citation(s) in RCA: 278] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 08/27/2008] [Accepted: 11/10/2008] [Indexed: 05/18/2023]
Abstract
BACKGROUND Water deficit (WD) decreases photosynthetic rate (A) via decreased stomatal conductance to CO(2) (g(s)) and photosynthetic metabolic potential (A(pot)). The relative importance of g(s) and A(pot), and how they are affected by WD, are reviewed with respect to light intensity and to experimental approaches. SCOPE AND CONCLUSIONS With progressive WD, A decreases as g(s) falls. Under low light during growth and WD, A is stimulated by elevated CO(2), showing that metabolism (A(pot)) is not impaired, but at high light A is not stimulated, showing inhibition. At a given intercellular CO(2) concentration (C(i)) A decreases, showing impaired metabolism (A(pot)). The C(i) and probably chloroplast CO(2) concentration (C(c)), decreases and then increases, together with the equilibrium CO(2) concentration, with greater WD. Estimation of C(c) and internal (mesophyll) conductance (g(i)) is considered uncertain. Photosystem activity is unaffected until very severe WD, maintaining electron (e(-)) transport (ET) and reductant content. Low A, together with photorespiration (PR), which is maintained or decreased, provides a smaller sink for e(-)(,) causing over-energization of energy transduction. Despite increased non-photochemical quenching (NPQ), excess energy and e(-) result in generation of reactive oxygen species (ROS). Evidence is considered that ROS damages ATP synthase so that ATP content decreases progressively with WD. Decreased ATP limits RuBP production by the Calvin cycle and thus A(pot). Rubisco activity is unlikely to determine A(pot). Sucrose synthesis is limited by lack of substrate and impaired enzyme regulation. With WD, PR decreases relative to light respiration (R(L)), and mitochondria consume reductant and synthesise ATP. With progressing WD at low A, R(L) increases C(i) and C(c). This review emphasises the effects of light intensity, considers techniques, and develops a qualitative model of photosynthetic metabolism under WD that explains many observations: testable hypotheses are suggested.
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Affiliation(s)
- David W Lawlor
- Plant Sciences, Centre for Crop Improvement, Rothamsted Research, Harpenden, Herts, UK.
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890
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Altenbach D, Rudiño-Pinera E, Olvera C, Boller T, Wiemken A, Ritsema T. An acceptor-substrate binding site determining glycosyl transfer emerges from mutant analysis of a plant vacuolar invertase and a fructosyltransferase. Plant Mol Biol 2009; 69:47-56. [PMID: 18821058 PMCID: PMC2709226 DOI: 10.1007/s11103-008-9404-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [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: 06/16/2008] [Accepted: 09/11/2008] [Indexed: 05/04/2023]
Abstract
Glycoside hydrolase family 32 (GH32) harbors hydrolyzing and transglycosylating enzymes that are highly homologous in their primary structure. Eight amino acids dispersed along the sequence correlated with either hydrolase or glycosyltransferase activity. These were mutated in onion vacuolar invertase (acINV) according to the residue in festuca sucrose:sucrose 1-fructosyltransferase (saSST) and vice versa. acINV(W440Y) doubles transferase capacity. Reciprocally, saSST(C223N) and saSST(F362Y) double hydrolysis. SaSST(N425S) shows a hydrolyzing activity three to four times its transferase activity. Interestingly, modeling acINV and saSST according to the 3D structure of crystallized GH32 enzymes indicates that mutations saSST(N425S), acINV(W440Y), and the previously reported acINV(W161Y) reside very close together at the surface in the entrance of the active-site pocket. Residues in- and outside the sucrose-binding box determine hydrolase and transferase capabilities of GH32 enzymes. Modeling suggests that residues dispersed along the sequence identify a location for acceptor-substrate binding in the 3D structure of fructosyltransferases.
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Affiliation(s)
- Denise Altenbach
- Zürich-Basel Plant Science Center, Botanisches Institut der Universität Basel, Hebelstrasse 1, 4056 Basel, Switzerland
- Bioreba AG, Chr. Merian-Ring 7, 4153 Reinach, Switzerland
| | - Enrique Rudiño-Pinera
- Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, MO 62250 Mexico
| | - Clarita Olvera
- Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, MO 62250 Mexico
| | - Thomas Boller
- Zürich-Basel Plant Science Center, Botanisches Institut der Universität Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | - Andres Wiemken
- Zürich-Basel Plant Science Center, Botanisches Institut der Universität Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | - Tita Ritsema
- Zürich-Basel Plant Science Center, Botanisches Institut der Universität Basel, Hebelstrasse 1, 4056 Basel, Switzerland
- Plant–Microbe Interactions, Institute of Environmental Biology, University Utrecht, Kruijtgebouw, Padualaan 8, 3584 CH Utrecht, The Netherlands
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891
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Shabala L. Organic vs inorganic: What makes the major contribution to osmotic adjustment in bacteria? Commun Integr Biol 2009; 2:74-5. [PMID: 19704892 PMCID: PMC2686347 DOI: 10.4161/cib.7473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 11/20/2008] [Accepted: 11/21/2008] [Indexed: 11/19/2022] Open
Abstract
In order to survive hyperosmotic stress bacteria should adjust their cell turgor to altered conditions by increasing the intracellular osmolality. The classical view is that bacterial osmotic adjustment is achieved via accumulation of so-called "compatible solutes"-some organic osmolytes that can be accumulated in the cytosol at high concentrations without interfering with cell metabolism. In our recently published paper,11 we have shown that in the absence of osmolytes in the environment uptake of inorganic ions (and, specifically, K(+)) is central to osmotic adjustment in E. coli under hyperosmotic stress conditions. Here we show that optimal E. coli growth, observed at 2% NaCl, corresponds to an osmotic balance between external and internal osmolality within bacterial cells. This is achieved by the regulation of net K(+) fluxes across the bacterial membrane. We suggest that the role of compatible solutes in osmotic adjustment in bacteria is indirect and confined to the fine tuning of a number of ion channels and transporters in order to achieve osmotic balance.
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Affiliation(s)
- Lana Shabala
- Menzies Research Institute; University of Tasmania; Tasmania, Australia
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892
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Borek S, Pukacka S, Michalski K, Ratajczak L. Lipid and protein accumulation in developing seeds of three lupine species: Lupinus luteus L., Lupinus albus L., and Lupinus mutabilis Sweet. J Exp Bot 2009; 60:3453-66. [PMID: 19635747 PMCID: PMC2724698 DOI: 10.1093/jxb/erp186] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [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: 05/14/2023]
Abstract
A comparative study was carried out on the dynamics of lipid accumulation in developing seeds of three lupine species. Lupine seeds differ in lipid content; yellow lupine (Lupinus luteus L.) seeds contain about 6%, white lupine (Lupinus albus L.) 7-14%, and Andean lupine (Lupinus mutabilis Sweet) about 20% of lipids by dry mass. Cotyledons from developing seeds were isolated and cultured in vitro for 96 h on Heller medium with 60 mM sucrose (+S) or without sucrose (-S). Each medium was additionally enriched with 35 mM asparagine or 35 mM NaNO3. Asparagine caused an increase in protein accumulation and simultaneously decreased the lipid content, but nitrate increased accumulation of both protein and lipid. Experiments with [1-14C]acetate and [2-14C]acetate showed that the decrease in lipid accumulation in developing lupine seeds resulted from exhaustion of lipid precursors rather than from degradation or modification of the enzymatic apparatus. The carbon atom from the C-1 position of acetate was liberated mainly as CO2, whereas the carbon atom from the C-2 position was preferentially used in anabolic pathways. The dominant phospholipid in the investigated lupine seed storage organs was phosphatidylcholine. The main fatty acid in yellow lupine cotyledons was linoleic acid, in white lupine it was oleic acid, and in Andean lupine it was both linoleic and oleic acids. The relationship between stimulation of lipid and protein accumulation by nitrate in developing lupine cotyledons and enhanced carbon flux through glycolysis caused by the inorganic nitrogen form is discussed.
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Affiliation(s)
- Slawomir Borek
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
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893
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Kwon S, Kim YJ, Kim MK. Effect of fructose or sucrose feeding with different levels on oral glucose tolerance test in normal and type 2 diabetic rats. Nutr Res Pract 2008; 2:252-8. [PMID: 20016727 PMCID: PMC2788191 DOI: 10.4162/nrp.2008.2.4.252] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [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: 07/16/2008] [Revised: 11/24/2008] [Accepted: 12/08/2008] [Indexed: 01/09/2023] Open
Abstract
This study was designed to determine whether acute fructose or sucrose administration at different levels (0.05 g/kg, 0.1 g/kg or 0.4 g/kg body weight) might affect oral glucose tolerance test (OGTT) in normal and type 2 diabetic rats. In OGTT, there were no significant differences in glucose responses between acute fructose- and sucrose-administered groups. However, in normal rats, the AUCs of the blood glucose response for the fructose-administered groups tended to be lower than those of the control and sucrose-administered groups. The AUCs of the lower levels fructoseor sucrose-administered groups tended to be smaller than those of higher levels fructose- or sucrose-administered groups. In type 2 diabetic rats, only the AUC of the lowest level of fructose-administered (0.05 g/kg body weight) group was slightly smaller than that of the control group. The AUCs of fructose-administered groups tended to be smaller than those of the sucrose-administered groups, and the AUCs of lower levels fructose-administered groups tended to be smaller than those fed higher levels of fructose. We concluded from this experiment that fructose has tendency to be more effective in blood glucose regulation than sucrose, and moreover, that smaller amount of fructose is preferred to larger amount. Specifically, our experiments indicated that the fructose level of 0.05 g/kg body weight as dietary supplement was the most effective amount for blood glucose regulation from the pool of 0.05 g/kg, 0.1 g/kg and 0.4 g/kg body weights. Therefore, our results suggest the use of fructose as the substitute sweetener for sucrose, which may be beneficial for blood glucose regulation.
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Affiliation(s)
- Sanghee Kwon
- Department of Food and Nutritional Sciences, Ewha Womans University, 11-1 Daehyung-dong, Seodaemun-gu, Seoul 120-750, Korea
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894
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Abstract
Rats avoid intake of a gustatory cue following pairings with a drug of abuse, such as morphine or cocaine. Despite the well-established rewarding properties of these drugs, the reduction in intake of the taste cue has been interpreted as a conditioned taste aversion for decades. In 1997, I proposed the reward comparison hypothesis suggesting that rats avoided intake of the drug-associated taste cue because the value of the taste cue pales in comparison to the highly rewarding drug of abuse expected in the near future. In this issue of Behavioral Neuroscience, A. C. W. Huang and S. Hsiao challenge the reward comparison hypothesis by showing parallels between amphetamine and LiCl-induced suppression of CS intake. This commentary addresses the current state of the reward comparison hypothesis in the context of the experiments completed by Huang and Hsiao and their new task-dependent drug effects hypothesis.
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Affiliation(s)
- Patricia Sue Grigson
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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895
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Rekarte-Cowie I, Ebshish OS, Mohamed KS, Pearce RS. Sucrose helps regulate cold acclimation of Arabidopsis thaliana. J Exp Bot 2008; 59:4205-17. [PMID: 18980951 PMCID: PMC2639016 DOI: 10.1093/jxb/ern262] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [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: 04/01/2008] [Revised: 09/23/2008] [Accepted: 10/06/2008] [Indexed: 05/19/2023]
Abstract
A test was carried out to see if sucrose could regulate cold-acclimation-associated gene expression in Arabidopsis. In plants and excised leaves, sucrose caused an increase in GUS activity, as a reporter for the activity of the cold-responsive COR78 promoter. This increase was transient at 21 degrees C but lasted for at least 4 d at 4 degrees C in continuous darkness. However, at 4 degrees C with a 16 h photoperiod, GUS activity was similarly high with solutions lacking sucrose or with different concentrations of sucrose. In peeled lower epidermis in the cold dark environment, 40 mM sucrose increased COR78 transcript abundance to substantially above that in the controls, but sorbitol had no effect. Similarly to the cold and dark conditions, sucrose increased COR78 transcript abundance in the epidermis in the warm light and warm dark environments, but not in a cold light environment. Sucrose had much less effect on COR78 transcript abundance in leaves without the lower epidermis. Thus sucrose regulates expression of COR78, possibly mainly in the epidermis, at the level of transcription. Furthermore, 40 mM sucrose at 4 degrees C for 24 h in constant darkness was sufficient to give the same GUS activity as in fully acclimated plants of the same age in a 16 h photoperiod, although by 48 h, GUS activity had become intermediate between control and fully cold-acclimated plants. Thus sucrose has a regulatory role in the acclimation of whole plants to cold and this may be important during diurnal dark periods.
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Affiliation(s)
| | | | | | - Roger S. Pearce
- School of Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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896
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Zhou Y, Chan K, Wang TL, Hedley CL, Offler CE, Patrick JW. Intracellular sucrose communicates metabolic demand to sucrose transporters in developing pea cotyledons. J Exp Bot 2008; 60:71-85. [PMID: 18931350 PMCID: PMC3071760 DOI: 10.1093/jxb/ern254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 09/05/2008] [Accepted: 09/09/2008] [Indexed: 05/18/2023]
Abstract
Mechanistic inter-relationships in sinks between sucrose compartmentation/metabolism and phloem unloading/translocation are poorly understood. Developing grain legume seeds provide tractable experimental systems to explore this question. Metabolic demand by cotyledons is communicated to phloem unloading and ultimately import by sucrose withdrawal from the seed apoplasmic space via a turgor-homeostat mechanism. What is unknown is how metabolic demand is communicated to cotyledon sucrose transporters responsible for withdrawing sucrose from the apoplasmic space. This question was explored here using a pea rugosus mutant (rrRbRb) compromised in starch biosynthesis compared with its wild-type counterpart (RRRbRb). Sucrose influx into cotyledons was found to account for 90% of developmental variations in their absolute growth and hence starch biosynthetic rates. Furthermore, rr and RR cotyledons shared identical response surfaces, indicating that control of transporter activity was likely to be similar for both lines. In this context, sucrose influx was correlated positively with expression of a sucrose/H(+) symporter (PsSUT1) and negatively with two sucrose facilitators (PsSUF1 and PsSUF4). Sucrose influx exhibited a negative curvilinear relationship with cotyledon concentrations of sucrose and hexoses. In contrast, the impact of intracellular sugars on transporter expression was transporter dependent, with expression of PsSUT1 inhibited, PsSUF1 unaffected, and PsSUF4 enhanced by sugars. Sugar supply to, and sugar concentrations of, RR cotyledons were manipulated using in vitro pod and cotyledon culture. Collectively the results obtained showed that intracellular sucrose was the physiologically active sugar signal that communicated metabolic demand to sucrose influx and this transport function was primarily determined by PsSUT1 regulated at the transcriptional level.
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Affiliation(s)
- Yuchan Zhou
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Katie Chan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Trevor L. Wang
- Metabolic Biology, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
| | - Cliff L. Hedley
- Metabolic Biology, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
| | - Christina E. Offler
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - John W. Patrick
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
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897
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King RW, Hisamatsu T, Goldschmidt EE, Blundell C. The nature of floral signals in Arabidopsis. I. Photosynthesis and a far-red photoresponse independently regulate flowering by increasing expression of FLOWERING LOCUS T (FT). J Exp Bot 2008; 59:3811-20. [PMID: 18836142 PMCID: PMC2576645 DOI: 10.1093/jxb/ern231] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [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: 06/09/2008] [Revised: 07/25/2008] [Accepted: 08/05/2008] [Indexed: 05/18/2023]
Abstract
Arabidopsis flowers in long day (LD) in response to signals transported from the photoinduced leaf to the shoot apex. These LD signals may include protein of the gene FLOWERING LOCUS T (FT) while in short day (SD) with its slower flowering, signalling may involve sucrose and gibberellin. Here, it is shown that after 5 weeks growth in SD, a single LD up-regulated leaf blade expression of FT and CONSTANS (CO) within 4-8 h, and flowers were visible within 2-3 weeks. Plants kept in SDs were still vegetative 7 weeks later. This LD response was blocked in ft-1 and a co mutant. Exposure to different LD light intensities and spectral qualities showed that two LD photoresponses are important for up-regulation of FT and for flowering. Phytochrome is effective at a low intensity from far-red (FR)-rich incandescent lamps. Independently, photosynthesis is active in an LD at a high intensity from red (R)-rich fluorescent lamps. The photosynthetic role of a single high light LD is demonstrated here by the blocking of the flowering and FT increase on removal of atmospheric CO(2) or by decreasing the LD light intensity by 10-fold. These conditions also reduced leaf blade sucrose content and photosynthetic gene expression. An SD light integral matching that in a single LD was not effective for flowering, although there was reasonable FT-independent flowering after 12 SD at high light. While a single photosynthetic LD strongly amplified FT expression, the ability to respond to the LD required an additional but unidentified photoresponse. The implications of these findings for studies with mutants and for flowering in natural conditions are discussed.
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Affiliation(s)
- Rod W King
- CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
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898
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Zhou K, Yamagishi M, Osaki M, Masuda K. Sugar signalling mediates cluster root formation and phosphorus starvation-induced gene expression in white lupin. J Exp Bot 2008; 59:2749-56. [PMID: 18487637 PMCID: PMC2486467 DOI: 10.1093/jxb/ern130] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [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: 02/19/2008] [Revised: 04/07/2008] [Accepted: 04/10/2008] [Indexed: 05/20/2023]
Abstract
Cluster root (CR) formation contributes much to the adaptation to phosphorus (P) deficiency. CR formation by white lupin (Lupinus albus L.) is affected by the P-limiting level in shoots, but not in roots. Thus, shoot-derived signals have been expected to transmit the message of P-deficiency to stimulate CR formation. In this study, it is shown that sugars are required for a response to P starvation including CR formation and the expression of P starvation-induced genes. White lupin plants were grown in vitro on P-sufficient or P-deficient media supplemented with sucrose for 4 weeks. Sucrose supply stimulated CR formation in plants on both P-sufficient and P-deficient media, but no CR appeared on the P-sufficient medium without sucrose. Glucose and fructose also stimulated CR formation on the P-sufficient medium. On the medium with sucrose, a high concentration of inorganic phosphate in leaves did not suppress CR formation. Because sorbitol or organic acid in the media did not stimulate CR formation, the sucrose effect was not due to increased osmotic pressure or enriched energy source, that is, sucrose acted as a signal. Gene transcription induced by P starvation, LaPT1 and LaPEPC3, was magnified by the combination of P limitation and sucrose feeding, and that of LaSAP was stimulated by sucrose supply independently of P supply. These results suggest that at least two sugar-signalling mediating systems control P starvation responses in white lupin roots. One system regulates CR formation and LaSAP expression, which acts even when P is sufficient if roots receive sugar as a signal. The other system controls LaPT1 and LaPEPC3 expression, which acts when P is insufficient.
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Affiliation(s)
- Keqin Zhou
- Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan
| | - Masumi Yamagishi
- Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan
| | - Mitsuru Osaki
- Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan
| | - Kiyoshi Masuda
- Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan
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899
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Stanhope KL, Griffen SC, Bair BR, Swarbrick MM, Keim NL, Havel PJ. Twenty-four-hour endocrine and metabolic profiles following consumption of high-fructose corn syrup-, sucrose-, fructose-, and glucose-sweetened beverages with meals. Am J Clin Nutr 2008; 87:1194-203. [PMID: 18469239 PMCID: PMC3037416 DOI: 10.1093/ajcn/87.5.1194] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [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] Open
Abstract
BACKGROUND We have reported that, compared with glucose-sweetened beverages, consuming fructose-sweetened beverages with meals results in lower 24-h circulating glucose, insulin, and leptin concentrations and elevated triacylglycerol (TG). However, pure fructose and glucose are not commonly used as sweeteners. High-fructose corn syrup (HFCS) has replaced sucrose as the predominant sweetener in beverages in the United States. OBJECTIVE We compared the metabolic/endocrine effects of HFCS with sucrose and, in a subset of subjects, with pure fructose and glucose. DESIGN Thirty-four men and women consumed 3 isocaloric meals with either sucrose- or HFCS-sweetened beverages, and blood samples were collected over 24 h. Eight of the male subjects were also studied when fructose- or glucose-sweetened beverages were consumed. RESULTS In 34 subjects, 24-h glucose, insulin, leptin, ghrelin, and TG profiles were similar between days that sucrose or HFCS was consumed. Postprandial TG excursions after HFCS or sucrose were larger in men than in women. In the men in whom the effects of 4 sweeteners were compared, the 24-h glucose and insulin responses induced by HFCS and sucrose were intermediate between the lower responses during consumption of fructose and the higher responses during glucose. Unexpectedly, postprandial TG profiles after HFCS or sucrose were not intermediate but comparably high as after pure fructose. CONCLUSIONS Sucrose and HFCS do not have substantially different short-term endocrine/metabolic effects. In male subjects, short-term consumption of sucrose and HFCS resulted in postprandial TG responses comparable to those induced by fructose.
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Affiliation(s)
- Kimber L Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616-8669, USA
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900
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Kwon B, Goltz M, Houpt TA. Expression of AP-1 family transcription factors in the amygdala during conditioned taste aversion learning: role for Fra-2. Brain Res 2008; 1207:128-41. [PMID: 18374904 PMCID: PMC2756721 DOI: 10.1016/j.brainres.2008.01.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [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: 05/04/2007] [Revised: 01/22/2008] [Accepted: 01/28/2008] [Indexed: 01/08/2023]
Abstract
Conditioned taste aversion (CTA) learning occurs after the pairing of a novel taste with a toxin (e.g. sucrose with LiCl). The immediate early gene c-Fos is necessary for CTA learning, but c-Fos alone cannot be sufficient for consolidation. The expression of other AP-1 proteins from the Fos- and Jun-families may also be required shortly after conditioning for CTA consolidation. To screen for the expression of AP-1 transcription factors within small subregions, RT-PCR analysis was used after laser capture microdissection of the amygdala. Rats were infused intraorally with 5% sucrose (6 ml/6 min) or injected with LiCl (12 ml/kg, 0.15 M, i.p.) or given sucrose paired with LiCl (sucrose/LiCl), or not treated; 1 h later their brains were dissected. The lateral (LA), basolateral (BLA), and central (CeA) subnuclei of the amgydala of single 5 microm sections from individual rats were dissected using the Arcturus PixCell II system. Semi-quantitative RT-PCR showed the consistent presence of c-Fos, Fra-2, c-Jun, and JunD in the amygdala. In situ hybridization confirmed that c-Fos and Fra-2 mRNA expression was increased in the CeA after LiCl and sucrose/LiCl treatment. Immunohistochemistry for Fra-2 revealed high baseline levels of Fra-2 protein in the BLA and CeA, but also an increase in Fra-2 in the BLA and CeA after LiCl and sucrose/LiCl treatment. The similarity of response in LiCl and sucrose/LiCl treated groups might reflect activation by LiCl in both groups. To control for the effects of LiCl, rats were tested in a learned safety experiment. Fra-2 and c-Fos were examined in response to sucrose/LiCl in rats with prior familiarity with sucrose compared to rats without prior exposure to sucrose. The familiar (pre-exposure) group showed a significantly decreased number of Fra-2-positive cells compared with the novel group in the BLA, but not in the CeA. Because pre-exposure to sucrose attenuates CTA learning, a decreased cellular response in pre-exposed rats suggests a specific correlation with CTA learning. Changes in Fra-2 and c-Fos expression in the BLA and CeA at the time of conditioning, together with constitutive expression of c-Jun and JunD, may contribute to CTA learning.
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Affiliation(s)
- Bumsup Kwon
- Department of Biological Science and Program in Neuroscience, The Florida State University, Tallahassee, FL 32306, USA
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