Academic literature on the topic 'Nitrite metabolism'
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Journal articles on the topic "Nitrite metabolism"
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Shi, Jiayang. "Nitrite Toxicity: Chemical Analysis, Metabolism, and Health Effects." Highlights in Science, Engineering and Technology 19 (November 17, 2022): 210–15. http://dx.doi.org/10.54097/hset.v19i.2852.
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Nitrites can be formed from and away by the nitrate-nitrite-nitric oxide pathway. The properties of nitrite oxidation and metHb formation are carefully studied in mechanism, forming either N-binding or O-binding structures. Apart from nitrate and nitric oxide, nitrites can also form carcinogenic nitrosamines in acidic environments. MetHb can cause hypoxia and vasodilation, while symptoms are revealed in different degrees under recalled or present hypoxic conditions. The study thoroughly studied nitrite’s metabolic properties, chemical pathways, and dosage effects on health. The cancer risks of consuming dietary nitrite need more statistical support, while its metabolite N-nitrosodimethylamine and NDMA concentration are well considered with increasing cancer risks. ED50 of human vasodilation is identified, and lethal doses on juvenile pike-perch can be further utilized to predict related doses for humans. More studies should be done to investigate relative nitrite doses to boost utilization and studies about this chemical.
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Curtis, Erin, Lewis L. Hsu, Yuen Yi Hon, Lisa Geary, Audrey C. Noguchi, and Sruti Shiva. "Nitrite Oxidase Activities of Cytochrome P450 and Mitochondria." Blood 118, no. 21 (November 18, 2011): 5310. http://dx.doi.org/10.1182/blood.v118.21.5310.5310.
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Abstract Abstract 5310 Once dismissed as an inert byproduct of nitric oxide (NO) auto-oxidation, nitrite (NO2−) is now accepted as an endocrine reserve of NO that elicits a number of fundamental biological responses in all major organ systems. While it is known that tissue nitrite is derived from both oxidation of NO and from dietary nitrite and nitrate, much less is known about how nitrite is metabolized by tissue or about the factors that influence this metabolism. Here we investigate the rates and mechanisms by which nitrite is metabolized by tissue over a range of oxygen tensions in rats and mice. We show that the rate of nitrite metabolism differs in heart, liver, lung and brain tissue. Further, oxygen regulates the rate and products of nitrite metabolism in each of these tissues. In hypoxic tissue, nitrite is predominantly reduced to NO, with significant formation of iron-nitrosyl heme proteins and S-nitrosothiols. Interestingly, this hypoxic nitrite metabolism is mediated by different sets of nitrite reductase enzymes in each tissue. In contrast, tissue consumption of nitrite is more rapid in normoxia and the major end product is nitrate. While cytochrome P450s and myoglobin contributed in the liver and heart respectively, mitochondrial cytochrome c oxidase played a significant role in this normoxic nitrite oxidation, which could be completely inhibited by cyanide in all tissues. We used cyanide-based nitrite preservation solution to measure the pharmacokinetics of oral and intraperitoneally administered nitrite in vivo. Using this methodology, we measured basal levels of nitrite in the major tissues and confirm that the heart contains the greatest concentration of nitrite, followed by the liver and finally the lung. We demonstrate that intraperitoneal administration of nitrite to mice increases nitrite levels most significantly in the liver and heart, where nitrite uptake is rapid (5–10 min) and steadily decreases thereafter, such that levels are back to baseline by 30 min. Little to no increase was observed in the lung. In these studies, changes in nitrate were difficult to detect due to the high levels of basal nitrate present in vivo and low concentration of nitrite administered. However, the rapid metabolism of nitrite in the tissue suggests that oxidation is at least partially responsible. In contrast to intraperitoneal nitrite, oral nitrite increased nitrite levels in all organs of mice, an effect which peaked in all organs except liver at 3 days. Collectively, these data provide insight into the fate of nitrite in tissue, the enzymes involved in hypoxic and normoxic nitrite metabolism and the role of oxygen in regulating these processes. Disclosures: No relevant conflicts of interest to declare.
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González-Soltero, Rocío, María Bailén, Beatriz de Lucas, Maria Isabel Ramírez-Goercke, Helios Pareja-Galeano, and Mar Larrosa. "Role of Oral and Gut Microbiota in Dietary Nitrate Metabolism and Its Impact on Sports Performance." Nutrients 12, no. 12 (November 24, 2020): 3611. http://dx.doi.org/10.3390/nu12123611.
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Nitrate supplementation is an effective, evidence-based dietary strategy for enhancing sports performance. The effects of dietary nitrate seem to be mediated by the ability of oral bacteria to reduce nitrate to nitrite, thus increasing the levels of nitrite in circulation that may be further reduced to nitric oxide in the body. The gut microbiota has been recently implicated in sports performance by improving muscle function through the supply of certain metabolites. In this line, skeletal muscle can also serve as a reservoir of nitrate. Here we review the bacteria of the oral cavity involved in the reduction of nitrate to nitrite and the possible changes induced by nitrite and their effect on gastrointestinal balance and gut microbiota homeostasis. The potential role of gut bacteria in the reduction of nitrate to nitrite and as a supplier of the signaling molecule nitric oxide to the blood circulation and muscles has not been explored in any great detail.
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Bueno, E., N. Gómez-Hernández, L. Girard, E. J. Bedmar, and M. J. Delgado. "Function of the Rhizobium etli CFN42 nirK gene in nitrite metabolism." Biochemical Society Transactions 33, no. 1 (February 1, 2005): 162–63. http://dx.doi.org/10.1042/bst0330162.
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Rhizobium etli CFN42 is not capable of growing anaerobically with nitrate but it grows with nitrite as a terminal electron acceptor. This bacterium contains the nirK gene encoding the copper-containing Nir (nitrite reductase), which is located on the cryptic plasmid pCFN42f. Mutational analysis has demonstrated that a nirK deficient mutant was not capable of growing under nitrite-respiring conditions. Moreover, microaerobic growth of this mutant was inhibited by the presence of nitrite. Nir activity and nitrite uptake were highly diminished in a nirK mutant, compared with the wild-type levels after incubation under anaerobic conditions. Our results suggest that the copper-containing Nir may have both a respiratory and a nitrite-detoxifying role in R. etli.
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Weiss, Bernard. "Evidence for Mutagenesis by Nitric Oxide during Nitrate Metabolism in Escherichia coli." Journal of Bacteriology 188, no. 3 (February 1, 2006): 829–33. http://dx.doi.org/10.1128/jb.188.3.829-833.2006.
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ABSTRACT In Escherichia coli, nitrosative mutagenesis may occur during nitrate or nitrite respiration. The endogenous nitrosating agent N2O3 (dinitrogen trioxide, nitrous anhydride) may be formed either by the condensation of nitrous acid or by the autooxidation of nitric oxide, both of which are metabolic by-products. The purpose of this study was to determine which of these two agents is more responsible for endogenous nitrosative mutagenesis. An nfi (endonuclease V) mutant was grown anaerobically with nitrate or nitrite, conditions under which it has a high frequency of A:T-to-G:C transition mutations because of a defect in the repair of hypoxanthine (nitrosatively deaminated adenine) in DNA. These mutations could be greatly reduced by two means: (i) introduction of an nirB mutation, which affects the inducible cytoplasmic nitrite reductase, the major source of nitric oxide during nitrate or nitrite metabolism, or (ii) flushing the anaerobic culture with argon (which should purge it of nitric oxide) before it was exposed to air. The results suggest that nitrosative mutagenesis occurs during a shift from nitrate/nitrite-dependent respiration under hypoxic conditions to aerobic respiration, when accumulated nitric oxide reacts with oxygen to form endogenous nitrosating agents such as N2O3. In contrast, mutagenesis of nongrowing cells by nitrous acid was unaffected by an nirB mutation, suggesting that this mutagenesis is mediated by N2O3 that is formed directly by the condensation of nitrous acid.
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Casella, Sergio, Anita Toffanin, Stefania Ciompi, Nora Rossi, and W. J. Payne. "Metabolism of nitrogen oxides and hydroxylamine in cells of true denitrifiers and Rhizobium "hedysari" HCNT1." Canadian Journal of Microbiology 40, no. 1 (January 1, 1994): 1–5. http://dx.doi.org/10.1139/m94-001.
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Cells of several copper-protein denitrifiers that produce nitrite reductase reduced nitrate to gaseous products but were completely or strongly inhibited by the copper chelator diethyldithiocarbamate (DDC), which did not comparably inhibit cells of cytochrome ed1 nitrite reductase producers. Both types of true denitrifiers released NO while reducing nitrite anaerobically in the presence of the uncoupler 3-chlorophenylhydrazonepropanedinitrile (CCCP), as seen previously only in Paracoccus denitrificons. In contrast, the pseudodenitrifier Rhizobium "hedysari" HCNT1, which grows as neither adenitrifier nor a fermenter, failed to reduce nitrate or nitrite or to nitrify ammonia when grown aerobically but reduced nitrite to N2O after growth at low oxygen tension even without any nitrogen oxide in the culture medium. Such oxygen-limited cells also formed N2O when incubated anaerobically with NO and hydroxylamine, and with nitrite and hydroxylamine as well, but not when anaerobic nitrite reduction (i.e., apparent production of NO) was inhibited by DDC. Rhizobium "hedysari" HCNT1 cells released no NO while reducing nitrite even in the presence of CCCP. The use of CCCP may permit differentiation of respiratory from nitrite-detoxifying denitrifying bacteria. Under aeration, but not anoxia, NO and hydroxylamine reacted to form N2O even in the absence of cells, providing a possible indicator of NO production assayable by gas chromatography.Key words: nitrite, nitric oxide, diethyldithiocarbamate (DDC), hydroxylamine, 3-chlorophenylhydrazonepropanedinitrile (CCCP).
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Karwowska, Małgorzata, and Anna Kononiuk. "Nitrates/Nitrites in Food—Risk for Nitrosative Stress and Benefits." Antioxidants 9, no. 3 (March 16, 2020): 241. http://dx.doi.org/10.3390/antiox9030241.
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In the context of impact on human health, nitrite/nitrate and related nitrogen species such as nitric oxide (NO) are a matter of increasing scientific controversy. An increase in the content of reactive nitrogen species may result in nitrosative stress—a deleterious process, which can be an important mediator of damage to cell structures, including lipids, membranes, proteins and DNA. Nitrates and nitrites are widespread in the environment and occur naturally in foods of plant origin as a part of the nitrogen cycle. Additionally, these compounds are used as additives to improve food quality and protect against microbial contamination and chemical changes. Some vegetables such as raw spinach, beets, celery and lettuce are considered to contain high concentrations of nitrates. Due to the high consumption of vegetables, they have been identified as the primary source of nitrates in the human diet. Processed meats are another source of nitrites in our diet because the meat industry uses nitrates/nitrites as additives in the meat curing process. Although the vast majority of consumed nitrates and nitrites come from natural vegetables and fruits rather than food additives, there is currently a great deal of consumer pressure for the production of meat products free of or with reduced quantities of these compounds. This is because, for years, the cancer risks of nitrates/nitrites have been considered, since they potentially convert into the nitrosamines that have carcinogenic effects. This has resulted in the development and rapid expansion of meat products processed with plant-derived nitrates as nitrite alternatives in meat products. On the other hand, recently, these two ions have been discussed as essential nutrients which allow nitric oxide production and thus help cardiovascular health. Thus, this manuscript reviews the main sources of dietary exposure to nitrates and nitrites, metabolism of nitrites/nitrates, and health concerns related to dietary nitrites/nitrates, with particular emphasis on the effect on nitrosative stress, the role of nitrites/nitrates in meat products and alternatives to these additives used in meat products.
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Ilma, Qoriatul, Achmad Dinoto, Ninu Setianingrum, Mulyadi Mulyadi, Dwi Agustyani, Nani Radiastuti, and Heddy Julistiono. "ISOLATION AND IDENTIFICATION OF BACTERIA REMOVING NITRITE, NITRATE, AND AMMONIUM FROM BIOBALLS FILTER." Indonesian Aquaculture Journal 17, no. 1 (June 29, 2022): 13. http://dx.doi.org/10.15578/iaj.17.1.2022.13-22.
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The presence of effective bacteria removing nitrite, nitrate, and ammonia in a recirculating aquaculture system (RAS) is necessary to attenuate their toxicity to fish. The research was conducted to find bacteria that can be cultured and reduce nitrite, nitrate, and ammonium. Sixteen bacterial colonies were isolated from bioballs of RAS biofilter and tested for their ability to reduce nitrite or nitrate concentrations. Using a simple indicator paper for nitrite and nitrate, four isolates that reduced nitrite and nitrate concentrations, namely K1NA3, K2NA3, CNA1, and PRO4NA1 were selected. The four isolates were then evaluated for the metabolism of nitrate, nitrite, and ammonium compounds using the spectrophotometry method. Results showed that the isolates K1NA3, CNA1, and PRO4NA1 reduced nitrite concentration but produced ammonium, whereas K1NA3 isolate was able to reduce nitrate concentration but produced both nitrite and ammonium. Experiments in reducing ammonium levels in the synthetic waste media showed the ability of four isolates to reduce ammonium levels after six days despite producing nitrite. Based on the 16S rRNA gene analysis, these isolates have a close relationship to Pseudomonas otitidis (KINA3 and K2NA3), Acinetobacter cumulans (CNA1), and Vogesella perlucida (PRO 4NA1).
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Truong, Phuoc Thien Hoang, Huynh Dan Do, Tran Quoc Thang Vo, and Phu Hoa Nguyen. "Isolation and selection of nitrite metabolising bacteria from the bottom mud of lobster culture area in Xuan Dai bay, Phu Yen province." Ministry of Science and Technology, Vietnam 63, no. 9 (September 25, 2021): 59–64. http://dx.doi.org/10.31276/vjst.63(9).59-64.
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The study had isolated and selected groups of bacteria that metabolise nitrite from the bottom mud of lobster cages in Xuan Dai bay, Phu Yen province. Analysis results from 21 sludge samples taken from 11 cages of lobster farming area isolated 16 strains of bacteria capable of nitrite metabolism. After investigating biological characteristics and nitrite metabolism of bacteria strains, 10 strains of bacteria were collected with the ability to metabolise nitrite over 95% in 72 hours. In addition, 10 strains of bacteria with the highest NO2- treatment efficiency, identified by genetic analysis and looked up on BLAST, defined as Stenotrophomonas pavanii, Chryseobacterium gleum, Stenotrophomonas maltophilia, Delftia lacustris, Acinetobacter junii
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van Bezooijen, RL, I. Que, AG Ederveen, HJ Kloosterboer, SE Papapoulos, and CW Lowik. "Plasma nitrate+nitrite levels are regulated by ovarian steroids but do not correlate with trabecular bone mineral density in rats." Journal of Endocrinology 159, no. 1 (October 1, 1998): 27–34. http://dx.doi.org/10.1677/joe.0.1590027.
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Nitric oxide (NO) is a mediator of bone metabolism and its production is under the control of gender hormones in several cell types or tissues. Changes in endogenous NO production, measured as plasma nitrate+nitrite levels, may therefore contribute to ovariectomy (OVX)-induced bone loss. We studied plasma nitrate+nitrite levels and trabecular bone mineral density (TBMD) 4 weeks after sham-operation or OVX in rats receiving various hormonal treatments. OVX decreased plasma nitrate+nitrite levels significantly and this was accompanied by a significant decrease in TBMD. Treatment with oral ethinyl oestradiol (EE) and subcutaneous 17beta-oestradiol dose-dependently prevented the decrease in plasma nitrate+nitrite levels after OVX, but treatment with oral 17beta-oestradiol did not. Oestrogen treatment, 17beta-oestradiol (s. c. or orally) or EE (orally), prevented the OVX-induced decrease in TBMD. Treatment of sham-operated rats with the anti-oestrogen ICI164, 384 induced a significant decrease in TBMD that corresponded to 54% of the decrease observed after OVX, but did not affect plasma nitrate+nitrite levels. Treatment of ovariectomized rats with Org 2058, a pure progestagen, did not prevent bone loss, but prevented the decrease in plasma nitrate+nitrite levels dose-dependently. Treatment with tibolone, a synthetic steroid with combined weak oestrogenic, progestagenic, and androgenic properties, or with progestagen in combination with EE completely prevented bone loss after OVX. These treatments, however, only partly prevented the OVX-induced decrease in plasma nitrate+nitrite levels. In conclusion, OVX decreased both TBMD and plasma nitrate+nitrite levels. Although plasma nitrate+nitrite levels were under the control of both oestrogen and progesterone, TBMD was affected by oestrogen only. Decreased systemic production of NO is, therefore, not involved in OVX-induced bone loss in rats.
Dissertations / Theses on the topic "Nitrite metabolism"
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Pinder, Andrew George. "Nitrite uptake and metabolism in human erythrocytes : a source of vascular nitric oxide?" Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/55834/.
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The primary function of the cardiovascular and pulmonary systems is to produce a flow of oxygenated blood in sufficient supply to maintain aerobic metabolism in all organs and tissues. The system is required to be energy efficient but also receptive to changes in cellular metabolic demand. In order to function both at rest and during demand the system must also match oxygen allocation to metabolic requirements at a localised level. Once blood enters an area that requires substrates, oxygen should have the capacity to efficiently move from the blood, across the vessel wall and into the tissue. Global oxygen delivery (DO2, product of cardiac output and arterial oxygen content) under normal, resting conditions is more than adequate to meet metabolic demands/oxygen consumption (VO2) (Figure 1.1). At a tissue level, oxygen delivery is governed by two processes, convective and diffusive oxygen transport. Convective transport can be described as the bulk movement of oxygen in the blood, encompassing changes in cardiac output and the mechanisms that regulate flow in the microcirculation. Diffusive oxygen transport simply refers to the movement of oxygen from the blood into tissue, down the capillary-intracellular oxygen tension (PO 2) gradient and is governed by arterial oxygen tension (PaO2).
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Mackerness, Craig William. "The products of bacterial metabolism of nitrate and nitride and human cancer." Thesis, Open University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334761.
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Kotwica, Aleksandra Olga. "Dietary nitrate and the modulation of energy metabolism in metabolic syndrome." Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708924.
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Camargos, Liliane Santos de. "Análise das alterações no metabolismo de nitrogênio em Canavalia ensiformes (L.) em resposta a variações na concentração de nitrato fornecida." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-25022003-141208/.
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O nitrogênio é o nutriente mineral essencial mais limitante ao crescimento das plantas. Apenas alguns microorganismos procariotos desenvolveram um mecanismo bioquímico que permite reduzir N2, abundante na atmosfera, a amônia, que pode ser assimilada pelas plantas. Muitos destes microorganismos conseguem associar-se simbioticamente com outros organismos, sendo a associação de bactérias do grupo Rhizobium com plantas do grupo das leguminosas a mais importante a nível econômico. Por outro lado, quando existe disponibilidade de nitrato no meio ambiente, a leguminosa abandona a fixação biológica absorvendo nitrato, que é reduzido a amônia pelas enzimas nitrato redutase (NR) e nitrito redutase (NiR) e, ao final, assimilada pelo sistema GS/GOGAT. Apesar de as duas vias terem amônia como produto final, em leguminosas tropicais, principalmente as pertencentes à tribo Phaseolae, quando a amônia provém de associação simbiótica a planta exporta, via xilema, preferencialmente ureídeos, enquanto quando a amônia provém da redução de nitrato, a planta exporta amidas, principalmente asparagina e glutamina. O objetivo do presente trabalho foi identificar, em Canavalia ensiformes (L.), as alterações metabólicas que ocorriam em função da concentração de nitrato fornecida à planta, através da quantificação localizada dos principais compostos nitrogenados do metabolismo de nitrogênio e dos principais sítios de redução de nitrato; bem como estudar o metabolismo de asparagina na leguminosa em questão desde o estádio de germinação até a fase reprodutiva, identificando os sítios preferenciais de metabolismo desta amida. Observou-se que o metabolismo de aminoácidos foi profundamente alterado em função da concentração de nitrato fornecida. Os níveis de aminoácidos solúveis totais não se alteraram drasticamente, o mesmo ocorrendo com os níveis de proteína e ureídeos, considerando-se os diferentes tratamentos em um mesmo estádio de desenvolvimento. Com a alteração do estádio de desenvolvimento, especialmente com o início da fase reprodutiva, o metabolismo de nitrogênio foi profundamente alterado, observando-se inversão no sítio de redução de nitrato, alterações nas concentrações totais de ureídeos e aminoácidos e alterações profundas no metabolismo de aminoácidos, quando se relaciona com o estádio vegetativo. A atividade de nitrato redutase, em Canavalia ensiformes (L.) mostrou-se regulada pela concentração de glutamina presente nos tecidos, tendo se mostrado mais elevada nos tecidos onde os níveis de glutamina eram menores. A alteração no sítio de redução de nitrato em função da mudança no estádio de desenvolvimento foi acompanhada pelo aumento simultâneo na concentração de glutamina solúvel nos tecidos onde a atividade da enzima foi menor. Em função das mudanças no estádio de desenvolvimento, percebeu-se também uma redução no número de sítios de possível atividade da enzima asparaginase, o que foi inferido pela redução no número de tecidos onde a enzima esteve presente, sugerindo então um possível aumento no catabolismo desta amida por ação da enzima asparagina-aminotransferase. Para maior entendimento dos processos que levam às alterações no metabolismo de nitrato, asparagina e aminoácidos de uma forma geral, os mecanismos de síntese e utilização de aminoácidos devem ser analisados para melhor compreensão dos processos envolvidos, através da análise da atividade das principais enzimas envolvidas nestes processos, bem como de estudos da transcrição dos respectivos genes.Nitrogen is the most limiting essential nutrient for plant growth. Some prokaryotic microorganisms have developed a biochemical mechanism, which allows the reduction of N2, which is abundantly present in the atmosphere, to ammonium that can be assimilated by the plants. Many of these microorganisms form symbiotic associations with other organisms. This is especially true for leguminous plants that form symbiotic associations with bacteria belonging to the Bradyrhizbium, Rhizobium, and Sinorhizobium groups. Bacterial nitrogen fixation from these interactions are extremely important for the global nitrogen balance and plays a major economically role in agriculture. On the other hand, when nitrate is available in the environment, leguminous plants interrupt the symbiotic fixation process to directly use of the nitrate, which is reduced to ammonium by the enzymes nitrate reductase (NR) and nitrite reductase (NiR), and is finally assimilated by the GS/GOGAST system. Although both will result in ammonium as the end-product, in tropical leguminous plants species, mainly those of the Phaseoleae tribe, when ammonium is produced by the symbiotic association the plant translocates mainly ureides via xylem, whereas the plant translocate mainly amides such as asparagine and glutamine, when the ammonium is produced by nitrate reduction. The objective of this study was to identify in Canavalia ensiformes (L.), metabolic alterations dependent upon the concentration of nitrate supplied to the plant. Specific attention was given to the quantity of nitrogen compounds from nitrogen metabolism and asparagine metabolism from the early stage of germination to the reproductive stage, with the identification of the main locations of metabolism for this amide. Amino acids metabolism was significantly altered when nitrate was supplied at different concentrations. Total soluble amino acids, total protein and ureide contents were not dramatically altered when considering the different treatments at the same developmental stage. However, nitrogen metabolism was shown to be drastically altered when different development stages were compared, particularly at the beginning of the reproductive stage, at which time a switch in the location of nitrate reduction, alterations in the total concentration of ureides and amino acids were observed, when compared to the vegetative stage. Nitrate reductase activity of Canavalia ensiformes was shown to be regulated by the concentration of glutamine present in the tissues, exhibiting higher activity in tissues containing lower concentrations of glutamine, which coincided with the shift of the site of nitrate reduction with the changing developmental stage. The understanding of the processes leading to the alterations in the metabolism of nitrate, asparagine, amino acids, and the mechanism related to the synthesis and utilization of amino acids requires further studies.
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Agell, Blenda. "Effect of Antibacterial Mouthwash on Basal Metabolic Rate in Humans : A Randomized, Double-blinded, Cross-over Study." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-30774.
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The use of mouthwash is a common complement to oral care. However, the physiological implication of this use, besides of effects on oral hygiene, is poorly known. The research of the gut micro flora and its implications on the host is a very active area of research today. Many important connections between the gut micro flora and obesity and diabetes have been found. These billions of bacteria are part of the immune system, they produce essential vitamins and they make inaccessible polysaccharides more digestible to the host, just to mention a few of their symbiotic roles for the host. A less explored area is the micro flora in the oral cavity. On the back of the tongue, anaerobic bacteria can reduce dietary nitrate to nitrite which then further can be reduced to nitric oxide, NO. NO is important in several important biological functions, e.g. as a signal substance, vasoregulation, mucus production and antibacterial effects. Vegetables as beetroot and spinach are dietary sources with a high nitrate content. Also drinking water and processed meats can be of relevance. Nitrite is added to processed meat for the prevention of botulism but also adds taste and color. Experiments on humans indicate that mitochondrial efficiency increases after nitrate load, manifested as a decreased oxygen demand during physical exercise. This can also be relevant under conditions where the mitochondrial function is impaired, such as in diabetes and cardiovascular diseases. First a pilot study was made to evaluate the nitrate reducing effect from the antibacterial mouthwash. The mouthwash proved very effective. The concentrations of nitrate and nitrite in saliva was analyzed by HPLC and saliva from the antibacterial treatment showed greatly reduced concentrations of nitrite and high concentrations of nitrate. Saliva from placebo mouthwash showed high concentrations of nitrite and low concentrations of nitrate as expected. To study the importance of oral bacteria on metabolism, we performed a randomized, cross-over double-blinded study with 19 healthy males between 22-43 years. During two separate three-day periods they used an antibacterial and placebo mouthwash, respectively. On the fourth day their basal metabolic rate (BMR) was measured with an indirect calorimetric system. Moreover, samples from saliva, urine and blood were collected but these results are not included in this thesis. An earlier, unpublished study has demonstrated that nitrate administration reduces the basal metabolic rate. Accordingly, our aim was to study potential effects on the basal metabolic rate following reduction of the number of oral bacteria by aid of antibacterial mouthwash. Our hypothesis was that the reduced availability of nitrite would decrease the availability of NO in the body and manifest as an increased basal metabolic rate. The results from indirect calorimetry measurements showed no significant difference between placebo and antibacterial mouthwash, but there may be confounding factors. Further study is needed to assess the potential effects on host metabolism by these bacteria.
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Mpongwana, Ncumisa. "Metabolic network modelling of nitrification and denitrification under cyanogenic conditions." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/2982.
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Thesis (PhD (Chemical Engineering))--Cape Peninsula University of Technology, 2019Simultaneous nitrification and aerobic denitrification (SNaD) is a preferred method for single stage total nitrogen (TN) removal, which was recently proposed to improve wastewater treatment plant design. However, SNaD processes are prone to inhibition by toxicant loading with free cyanide (CN-) possessing the highest inhibitory effect on such processes, rendering these processes ineffective. Despite the best efforts of regulators to limit toxicant disposal into municipal wastewater sewage systems (MWSSs), free cyanide (CN-) still enters MWSSs through various pathways; hence, it has been suggested that CN- resistant or tolerant microorganisms be utilized for processes such as SNaD. To mitigate toxicant loading, organisms in SNaD have been observed to adopt a multiphase growth strategy to sequentially degrade CN- during primary growth and subsequently degrade TN during the secondary growth phase. However, CN- degrading microorganisms are not widely used for SNaD in MWSSs due to the inadequate application of suitable microorganisms (Chromobacterium violaceum, Pseudomonas aeruginosa, Thiobacillus denitrificans, Rhodospirillum palustris, Klebsiella pneumoniae, and Alcaligenes faecalis) commonly used in single-stage SNaD. The use of CN- degrading or resistant microorganisms for SNaD is a cost-effective method compared to the use of other methods of CN- removal prior to TN removal, as they involve multi-stage systems (as currently observed in MWSSs). The use of CN- degrading microorganisms, particularly when used as a consortium, presents a promising and sustainable resolution to mitigate inhibitory effects of CN- in SNaD. However, SNaD is known to be completely inhibited by CN- thus it is imperative to also study some thermodynamic parameters of SNaD under high CN- conditions to see the feasibility of the process. The Gibbs free energy is significant to understand the feasibility of SNaD, it is also vital to study Gibbs free energy to determine whether or not the biological reaction is plausible. The relationship between the rate of nitrification and Gibbs free energy was also investigated. The attained results showed that up to 37.55 mg CN-/L did not have an effect on SNaD. The consortia degraded CN- and achieved SNaD, with degradation efficiency of 92.9 and 97.7% while the degradation rate of 0.0234 and 0.139 mg/L/hr for ammonium-nitrogen (NH4-N) and CN- respectively. Moreover, all the free Gibbs energy was describing the individual processes were found to be negative, with the lowest Gibbs free energy being -756.4 and -1830.9 Kcal/mol for nitritation and nitratation in the first 48 h of the biological, reaction respectively. Additionally, a linear relationship between the rate of NH4-N and nitrite-nitrogen (NO2-N) degradation with their respective Gibbs free energy was observed. Linear model was also used to predict the relationship between NH4-N, NO2-N degradation and Gibbs free energy. These results obtained showed a good correlation between the models and the experimental data with correlation efficiency being 0.94 and 0.93 for nitritation, and nitratation, respectively. From the results found it can be deduced that SNaD is plausible under high cyanide conditions when cyanide degrading or tolerant microorganisms are employed. This can be a sustainable solution to SNaD inhibition by CN- compounds during wastewater treatment. Furthermore, a single strain was purified from the consortium and identified as Acinetobacter courvalinii. This bacterial strain was found to be able to perform sequential CN- degradation, and SNaD; an ability associated with multiphase growth strategy of the microorganism when provided with multiple nitrogenous sources, i.e. CN- and TN. The effect of CN- on nitrification and aerobic denitrification including enzyme expression, activity and protein functionality of Acinetobacter courvalinii was investigated. It was found that CN- concentration of up to 5.8 mg CN-/L did not affect the growth of Acinetobacter courvalinii. In cultures whereby the A. courvalinii isolate was used, degradation rates of CN- and NH4-N were found to be 2.2 mg CN-/L/h and 0.40 mg NH4-N/L/h, respectively. Moreover, the effect of CN- on NH4-N, nitrate-nitrogen (NO3-N) and NO2-N oxidizing enzymes was investigated, with findings indicating CN- did not affect the expression and activity of ammonia monooxygenase (AMO), but affected the activity of nitrate reductase (NaR) and nitrite reductase (NiR). Nevertheless, a slow decrease in NO2-N was observed after the addition of CN- thus confirming the activity of NaR and the activation of the denitrification pathway by the CN-. Moreover, five models’ (Monod, Moser, Rate law, Haldane, and Andrew’s model) ability to predict SNaD under CN- conditions, indicated that only Rate law, Haldane and Andrew’s models, were suited to predict both SNaD and CN- degradation. Due to low degradation rates of NH4-N and CN-, optimization of SNaD was essential. Therefore, response surface methodology was used to optimize the SNaD under CN- conditions. The physiological parameters that were considered for optimization were temperature and pH; with the result showing that the optimum for pH and temperature was 6.5 and 36.5oC respectively, with NH4-N and CN- degradation efficiency of 50 and 80.2%, respectively. Furthermore, the degradation kinetics of NH4-N and CN- were also studied under the optimum conditions in batch culture reactors, and the results showed that up to 70.6% and 97.3% of NH4-N and CN- were simultaneously degraded with degradation rates of 0.66 and 0.41 mg/L/h, respectively. The predictive ability of RSM was further compared with cybernetic models, and cybernetic models were found to better predict SNaD under CN- conditions. These results exhibited a promising solution in the management of inhibition effected of CN- towards SNaD at an industrial scale.
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Camargos, Liliane Santos de. "Alterações no metabolismo de compostos nitrogenados em Calopogonium mucunoides em resposta a diferentes fontes de nitrogênio : efeitos na nodulação e na fixação." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315648.
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Orientador: Ladaslav SodekTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Calopogonium mucunoides é uma leguminosa tropical típica de cerrado, sendo muito utilizada em adubação verde e como forrageira. Possui alta capacidade de fixação de nitrogênio, sendo cultivada em solos de baixo pH e pouca fertilidade; e boa resistência à seca, mas não tolera baixas temperaturas. Poucos são os estudos acerca do metabolismo de nitrogênio nesta espécie, mas demonstram que a leguminosa apresenta alta abundância relativa de ureídeos quando fixando nitrogênio. Estudos preliminares nossos demonstraram certa tolerância do mecanismo de fixação à exposição ao nitrato. Este trabalho objetivou estudar o metabolismo de nitrogênio, em Calopogonium mucunoides, identificando as principais alterações no metabolismo de nitrogênio sob diferentes condições de obtenção deste nutriente: plantas cultivadas recebendo solução nutritiva com diferentes fontes de nitrogênio antes da nodulação; e plantas plenamente noduladas, então expostas a receber solução nutritiva com diferentes fontes de nitrogênio, em diferentes concentrações e por diferentes tempos de exposição. Observou-se que a espécie não apresentou nodulação sensível à presença de nitrogênio no meio e, quando plantas plenamente noduladas foram expostas ao nitrogênio, a fixação foi mantida e a atividade da enzima nitrogenase só foi afetada, embora não totalmente, quando as plantas foram expostas a concentrações de 30 mM de nitrato. Por outro lado, a espécie parece responder à fonte de nitrogênio translocando e/ou acumulando diferentes formas de ureídeo (alantoína e ácido alantóico), mas o metabolismo de aminoácidos não apresentou resposta padrão à exposição ao nitrogênio. Estes estudos indicaram tolerância da nodulação e da fixação de nitrogênio desta espécie ao cultivo na presença de nitrogênio, podendo então servir de embasamento a futuros estudos acerca da sensibilidade/tolerância desses processos à presença de nitrogênio no meio em leguminosas em geral
Abstract: Calopogonium mucunoides is a tropical legume found in the ¿cerrado¿ (savanna) regions, and widely used as green manure and forage. It has a high capacity for fixing nitrogen, being cultivated in soils with low pH and poor fertility; and good resistance to drought, but does not tolerate low temperatures. Studies on the nitrogen metabolism of this species are quite scarce but it is known that the legume has a high relative abundance of ureides when fixing nitrogen. Our own preliminary studies suggested certain tolerance of fixation to the presence of nitrate. The objective of the present study was to study nitrogen metabolism in Calopogonium mucunoides, identifying the influence of the nitrogen source on nitrogen metabolism using: different nitrogen sources starting before nodulation; and exposing plants to the same sources only after complete nodulation, at different concentrations and times of exposure. It was found that the nodulation process of this species was not sensitive to the presence of a nitrogen source in the medium and, when fully nodulated plants were exposed to the nitrogen sources, fixation was maintained and the activity of nitrogenase was only affected, albeit partially, when exposed to the highest (30 mM) dose of nitrate. On the other hand, the species appears to respond to the exogenous source of nitrogen by translocating and/or accumulating different forms of ureides (allantoin and allantoic acid), but the metabolism of amino acids did not respond clearly to the nitrogen source. The data indicate that the process of nodulation and nitrogen fixation in this species is tolerant to the presence of a nitrogen source in the medium and should prove useful for future studies on the sensitivity/tolerance of nitrogen fixation to na external nitrogen source in legumes
Doutorado
Doutor em Biologia Vegetal
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Poucet, Théo. "The energy cost of primary metabolism and vacuole expansion : Central to shape tomato leaf development under ammonium nutrition." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0079.
Full textAbstract:
L'ammonium (NH4+) est une source d'azote d'un grand intérêt dans le cadre d'une agriculture durable. Son application en champs avec des inhibiteurs de nitrification s’est montré efficace pour limiter les pertes de N par rapport à l'utilisation de nitrate (NO3-). NH4+ est un intermédiaire commun impliqué dans de nombreuses voies métaboliques. Cependant, des concentrations élevées peuvent conduire à une situation de stress chez la plante provoquant un « syndrome ammoniacal », caractérisé par une croissance réduite. Ces symptômes sont causés par la combinaison, entre autres, d'une reprogrammation métabolique, d'une perturbation de la photosynthèse, d'une dérégulation du pH et d'un déséquilibre ionique. De nombreuses études ont décrit la façon dont la plante s’adapte à la nutrition ammoniacale. Cependant, le stade de développement des organes a été souvent négligé.Pour combler cette lacune, dans le premier chapitre nous étudions comment le métabolisme s’adapte en fonction de la position des feuilles sur l'axe vertical de plants de tomates (Solanum lycopersicum) cultivées en présence de NH4+, NO3- ou NO3NH4. Nous avons disséqué la composition de la biomasse foliaire et le métabolisme grâce à une analyse complète des métabolites, ions et activités enzymatiques. Nos résultats montrent que l'ajustement métabolique du C et du N en fonction de la source d'azote était plus intense chez les feuilles âgées par rapport au plus jeunes. Surtout, nous révélons un compromis entre l'accumulation de NH4+ et l'assimilation afin de préserver les jeunes feuilles du stress ammoniacal. Par ailleurs, les plantes alimentées en NH4+ présentaient un réarrangement des squelettes carbonés impliquant un coût énergétique élevé. Nous expliquons une telle réallocation par l'action du pH-stat biochimique, pour compenser la production différentielle de protons dépendante de la forme azotée fournie.La nutrition ammoniacale peut limiter l'expansion cellulaire. Entre autres, la croissance cellulaire dépend largement de la pression interne exercée par la vacuole sur la paroi cellulaire. Cependant, l’impact du stress ammoniacal sur la vacuole a été rarement abordé. Dans le second chapitre, nous évaluons l'effet de la nutrition ammoniacale sur le développement des feuilles en se focalisant sur l'expansion et le métabolisme vacuolaire. Pour cela, nous avons suivi le développement d’une feuille depuis son apparition jusqu'à son expansion complète avec du NH4+ ou NO3- comme seule source d'azote. Nous avons d’abord mis en évidence que la réduction de l’expansion cellulaire en nutrition ammoniacal était associée à des vacuole plus petite et aussi plus acide que celles recevant du NO3-. De plus, un modèle a été construit pour prédire l'équilibre thermodynamique de différentes espèces solubles de part et d’autre du tonoplaste. Le modèle intègre les volumes subcellulaires, les gradients électrochimiques et la formation de complexe ionique dans la vacuole afin de prédire les concentrations subcellulaires des ions, acides organiques et sucres mesurée dans la feuille. De plus, ces prédictions ont été validées avec des données obtenus par fractionnement non aqueux. Finalement, l’estimation des flux de soluté dans la vacuole nous a permis de démontrer que la déficience en malate dans les cellules des feuilles nourries avec NH4+ est central dans la limitation de l'expansion vacuolaire. De plus, nous concluons que le coût énergétique du transport de soluté dans la vacuole est plus élevé sous nutrition ammoniacale en raison du gradient électrochimique plus élevé généré de part et d’autre du tonoplaste. Ce travail souligne l'importance de considérer l'état phénologique des feuilles lors de l'étude du métabolisme de l'azote. De plus, notre approche place le contrôle du pH cytosolique et l'expansion des vacuoles au centre de l'adaptation des feuilles de tomate à ce stress et ouvre la voie à de futures études dans le domaine de la nutrition ammoniacalAmmonium (NH4+) is a nitrogen source of great interest in the context of sustainable agriculture. Its application in the field together with nitrification inhibitors has been extensively proven efficient to limit detrimental N losses compared to the use of nitrate (NO3-). NH4+ is a common intermediate involved in numerous metabolic routes. However, high NH4+ concentrations may lead to a stress situation provoking a set of symptoms collectively known as “ammonium syndrome” mainly characterized by growth retardation. Those symptoms are caused by a combination of, among others, a profound metabolic reprogramming, disruption of photosynthesis, pH deregulation and ion imbalance. Numerous studies have described the way plant copes to ammonium nutrition. However, the organ developmental stage has been generally neglected.To fill in this gap, in the first chapter we first aimed studying how the metabolism is adapted in function of the leaf position in the vertical axis of the tomato plants (Solanum lycopersicum) grown with NH4+, NO3- or NO3NH4 supply. To do so, we dissected leaf biomass composition and metabolism through a complete analysis of metabolites, ions and enzyme activities. The results showed that C and N metabolic adjustment in function of the nitrogen source was more intense in older leaves compared to younger ones. Importantly, we propose a trade-off between NH4+ accumulation and assimilation to preserve young leaves from ammonium stress. Besides, NH4+-fed plants exhibited a rearrangement of carbon skeletons with a higher energy cost respect to plants supplied with NO3-. We explain such reallocation by the action of the biochemical pH-stat, to compensate the differential proton production that depends on the nitrogen form provided.Ammonium nutrition may limit cell expansion, suggesting that the cellular processes involved would be altered. Among others, cell growth is largely dependent of the internal pressure exerted on the cell wall by the vacuole. However, the role of the vacuole in ammonium stress has been rarely addressed. In the second chapter, we evaluated the effect of ammonium stress on leaf development with a special focus on vacuole expansion and metabolism. To carry out this aim, we monitored the leaf development from its appearance until its complete expansion in plants grown under NH4+ or NO3- as unique nitrogen source. Cytological analysis evidenced that the reduced cell expansion under ammonium nutrition was associated with smaller vacuole size. Besides, we reported an acidification of the vacuole of NH4+-fed plants compared to nitrate nutrition. Moreover, a model was built to predict the thermodynamic equilibrium of different soluble species across the tonoplast. The model was set up through an extensive reviewing of vacuolar transporters and integrated subcellular volumes, vacuolar electrochemical gradients and the formation of ionic complex in the vacuole to fit the subcellular concentration of ions, organic acids and sugars measured in the leaf. Further, predictions obtained with the model were cross validated with data from non-aqueous fractionation. Firstly, the entrance of solutes was higher in vacuoles of NO3--fed leaves but was not associated with higher vacuolar osmolarity likely because of the adjustment of the vacuolar volume. In this sense, we proposed that the lack of malate in cells of ammonium-fed leaves was central in the limitation of vacuolar expansion. Secondly, we conclude that the energy cost of solute transport into the vacuole is higher under NH4+ nutrition because of the higher electrochemical gradient generated by the proton pumps across tonoplast.This work highlights the importance of considering leaf phenological state when studying nitrogen metabolism. In addition, our integrated approach place cytosolic pH control and vacuole expansion in the center of tomato leaf adaptation to ammonium stress and pave the way for future studies in the field of ammonium nutrition
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Pereira, Paula Natália. "Divisão espacial da atividade das enzimas PEPC e da NR e sua regulação por citocininas em folhas de Guzmania monostachia induzidas ao CAM." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-19122012-215637/.
Full textAbstract:
Estudos anteriores realizados no Laboratório de Fisiologia Vegetal do IBUSP com Guzmania monostachia demonstraram que quando essas plantas são submetidas ao déficit hídrico ocorre a indução do CAM, com maior expressão desse metabolismo na porção foliar apical. Para outra espécie (Vriesea gigantea), foi verificada a maior atividade da enzima nitrato redutase (NR) na porção basal durante o período diurno. Em uma bromélia terrestre (Ananas comosus) foi observada a sinalização por citocininas tanto na indução da expressão gênica, quanto na ativação da NR. Outros laboratórios evidenciaram que plantas de Mesembryanthemum crystallinum induzidas ao CAM apresentaram uma provável regulação negativa da fosfoenolpiruvato carboxilase (PEPC) por citocininas. Em decorrência desses conhecimentos acumulados, surgiram novos questionamentos: haveria variações diuturnas da atividade das enzimas PEPC e NR nas diferentes porções das folhas de G. monostachia induzidas ao CAM? A maior disponibilidade de esqueletos carbônicos à noite (acúmulo de acidez) influenciaria positivamente a atividade da NR, deslocando seu pico de atividade para o período noturno? As variações dos teores endógenos de citocininas acompanhariam as possíveis mudanças da atividade da PEPC e da NR, indicando, assim, a participação dessa classe hormonal na regulação dessas enzimas? O presente trabalho teve por objetivo principal investigar uma possível regulação da atividade das enzimas PEPC e NR por citocininas em folhas destacadas da bromélia epífita com tanque, Guzmania monostachia (Bromeliaceae) induzidas ao CAM. Foi esperado com esta pesquisa aprofundar os estudos sobre a inter-relação entre o comportamento fotossintético, a capacidade de assimilação de nitrogênio e a possível regulação das atividades da PEPC e da NR por citocininas endógenas. Análises de acidez titulável, ácidos orgânicos, amido endógeno e da atividade da enzima malato desidrogenase (MDH) foram realizadas, confirmando a indução do CAM nas folhas isoladas de G. monostachia mantidas em polietilenoglicol (PEG) a uma concentração de 30%. O uso desse composto foi eficiente na redução do conteúdo relativo de água e na imposição da deficiência hídrica foliar. Além disso, pôde-se verificar a maior expressão do CAM na porção apical das folhas mantidas em PEG 30%, quando comparada à porção basal. Análises da atividade da PEPC e da NR permitiram verificar a separação espacial dessas enzimas. A primeira apresentou maior atividade no ápice foliar, enquanto a segunda mostrou a maior atividade na porção basal. Apesar disso, não foi observada a separação temporal dessas enzimas, uma vez que ambas apresentaram picos de atividade noturna. A maior atividade da NR durante o período escuro (01 hora) foi verificada nas folhas-controle ou sob deficiência hídrica. Esse resultado sugere que outros fatores, diferentes do metabolismo CAM, influenciaram para a ocorrência da maior atividade dessa enzima durante o período noturno. Os resultados obtidos ainda sugerem que as citocininas possivelmente atuaram como um regulador negativo para a atividade da PEPC durante o dia, uma vez que os maiores níveis endógenos desse hormônio foram observados durante esse período, enquanto a maior atividade dessa enzima foi verificada durante a noite, quando os teores de Z+iP decaíram significativamente. A aplicação de Z ou iP resultou também num decréscimo da atividade dessa enzima. Por outro lado, as citocininas atuaram como um provável regulador positivo para a atividade da NR, uma vez que a maior atividade noturna dessa enzima foi antecedida em 3 ou 6 horas pelos maiores níveis endógenos de citocininas na porção basal das folhas mantidas em água ou PEG 30%, respectivamente. A aplicação de citocininas-livres aumentou significativamente a atividade da NR na base das folhas destacadas mantidas em água ou PEG 30%Prior studies undertaken in the Laboratory of Plant Physiology on IBUSP with Guzmania monostachia have shown that during water shortage, CAM induction occurs with greater expression in the apical portion of the leaf. In the case of another species (Vriesea gigantean), more intense nitrate reductase (NR) enzyme activity was observed in the basal portion during the daytime. In a certain terrestrial bromeliad (Ananas comosus), signaling by cytokinins, both in the induction of gene expression as well as NR activation, was observed. According to other laboratories, the cytokinins seem to play a negative regulation of phosphoenolpyruvate carboxylase (PEPC) in CAM induced Mesembryanthemum crystallinum plants. As a result of accumulated knowledge, new questions have arisen, such as: Are there daily variations in PEPC and NR enzymes activity in the different portions of CAM induced leaves of G. monostachia? Would the more pronounced nocturnal availability of carbon skeletons (accumulation of acidity) positively influence NR activity, with consequential displacement of its peak of activity to this period? Would variations in endogenous cytokinins concentration accompany possible changes in PEPC and NR activity, thereby indicating the participation of this hormonal class in their regulation? The main aim in the present study was to investigate the possible regulation of PEPC and NR activity by cytokinins in detached CAM-induced leaves of the epiphyte tank bromeliad Guzmania monostachia (Bromeliaceae). The expectations with this research were to study more deeply the inter-relationship between photosynthetic behavior, the capacity for nitrogen assimilation and the possible regulation of PEPC and NR activity by endogenous cytokinins. Analyses of titratable acidity, organic acids, endogenous starch and malate dehydrogenase (MDH) enzyme activity confirmed CAM induction in isolated leaves of G. monostachia kept in polyethylene glycol (PEG) at a concentration of 30%. The use of this compound was efficient in reducing relative water content and imposing leaf water deficiency. Furthermore, compared to the basal portion, greater CAM expression could be observed in the apical portion of leaves kept in PEG 30%. Analyses of PEPC and NR activity allowed detecting their mutual spatial separation, seeing that, in the first greater activity was concentrated in the leaf apex, while in the second this was more pronounced in the basal portion. Even so, no temporal separation could be observed, since peak of activity for both occurred at night. The peak of nocturnal NR activity (1 hour) was observed in control leaves or those undergoing water deficiency, thereby implying that factors, other than CAM metabolism, exerted an influence on the occurrence of more intense activity of this enzyme at this time. Furthermore, there were indications that cytokinins possibly act as a negative regulator of PEPC activity during the daytime, when the highest endogenous levels of this hormone were observed, whereas it was apparent that the most intense activity of this enzyme actually occurred at night, when Z+iP rates decreased significantly. Z or iP application also induced a decrease in the activity of this enzyme. On the other hand, the cytokinins acted as a positive regulator of NR activity, since the nocturnal peak of activity of this enzyme was preceded by 3 or 6 hours by higher endogenous levels of cytokinins in the basal portion of leaves maintained in water or PEG 30%, respectively. The application of free cytokinins induced a significant increase in NR activity in the base of detached leaves kept in water or PEG 30%
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Neto, Ana Paula. "Metabolismo do nitrogênio e concentração de nutrientes no cafeeiro irrigado em razão da dose de N." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-18022010-140953/.
Full textAbstract:
A adubação nitrogenada e sua implicação no metabolismo do cafeeiro ainda não são bem conhecidas nas condições de campo, em cafeicultura altamente tecnificada, com temperatura média de outono-inverno superior a 22 ºC e maior quantidade de horas-luz. O objetivo da presente pesquisa foi avaliar a atividade das enzimas redutase do nitrato (RN), glutamina sintetase (GS) e urease em função da dose de nitrogênio (sem N, 200, 400, 600 e 800 kg ha-1). Avaliou-se também a influência das doses de N (uréia) nas concentrações de N-total, nitrato, amônio, clorofila e carotenóides presentes nas folhas; as flutuações de macro e micronutrientes; bem como a correlação entre a produtividade e doses de N. Objetivou-se também identificar a época do pico da atividade da RN. Os experimentos foram realizados no Oeste baiano e em Piracicaba, SP. As avaliações foram realizadas nas fases fenológicas: vegetação, antese, fruto chumbinho, granação e maturação. A maior atividade da RN ocorreu com o fornecimento de 800 kg ha-1 de N, sem variação nas demais doses, bem como não influenciou a atividade da GS e urease. As concentrações de nitrato e amônio não aumentaram com as doses de N, mas a concentração de aminoácidos foi crescente com a dose do nutriente. A maior atividade da RN verificou-se na fase de vegetação e granação dos frutos, a qual foi superior às 12:00 h, enquanto as atividades da GS e urease foram superiores na fase de granação dos frutos. A maior concentração de nitrato se deu entre a fase de fruto chumbinho e início da granação e do amônio no final da granação. O pico da atividade da RN aconteceu aos 25 dias após a adubação nitrogenada. O uso de altas doses de N não prejudicou a concentração de macro e micronutrientes foliar. Finalmente, a máxima produtividade do cafeeiro foi obtida com a aplicação de 400 kg ha-1 de N.The nitrogen fertilization and its implication in the nitrogen metabolism of coffee plants are not well known in high technology production under field conditions with autumn-winter average temperatures above 22 º C and a larger photoperiod. The objective of this work was to evaluate the nitrate reductase, glutamine synthetase and urease activity due to nitrogen fertilization rates (without N, 200, 400, 600 e 800 kg ha-1). In the present work was evaluated also the influence of nitrogen rates on total nitrogen, nitrate, ammonium, chlorophylls and carotenoids concentration in the leaves, the variation of macro and micronutrients as well as the correlationship between coffee yield and nitrogen fertilization rates. Moreover, the goal of this study was to identify the period of peak activity of nitrate reductase. The experiment was carried out at western of Bahia State and Piracicaba, State of Sao Paulo, Brazil. The periods of evaluations were plant growth, anthesis, pin head fruits, filling and maturation fruits stage development. The highest nitrate reductase activity occurred with 800 kg ha-1 N supply and no changes on this enzyme were observed regarding other rates. Therefore, the nitrogen rates did not affect the glutamine synthetase and urease activity. The nitrate and ammonium concentration did not increase with nitrogen rates; however, the aminoacids concentration increased due to nitrogen fertilization rates. The highest activity of nitrate reductase was observed at 12:00h during plant growth and filling fruits stage development. On the other hand, the higher activity of glutamine synthetase and urease were during filling fruits stage. The highest nitrate concentration was detected during between pin head and beginning of filling fruits stage, and the highest ammonium concentration was during end of filling fruits stage development. The peak activity of nitrate reductase was 25 days after nitrogen fertilization. The high nitrogen rates did not affect the macro and micronutrients concentration in the leaves. The greater coffee yield was provided with 400kg ha-1 of nitrogen supply.
Books on the topic "Nitrite metabolism"
1
Khan, M. Nasir, Mohammad Mobin, Firoz Mohammad, and Francisco J. Corpas, eds. Nitric Oxide in Plants: Metabolism and Role in Stress Physiology. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06710-0.
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2
Talbot, R. J. Biokinetics of 237Pu-citrate and nitrate in rats after the intravenous injection of only 2 pg plutonium. Oxfordshire, OX: Environmental and Medical Sciences Divison, Harwell Laboratory, 1989.
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3
Giménez, Maria Sofia. Advances in chemistry and biology of nitric oxide. Kerala, India: Research Signpost, 2007.
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4
C, Fang Ferric, ed. Nitric oxide and infection. New York: Kluwer Academic/Plenum Publishers, 1999.
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Nitrile oxides, nitrones, and nitronates in organic synthesis: Novel strategies in synthesis. New York, N.Y: VCH Publishers, 1988.
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Stanislaw, Lukiewicz, and Zweier Jay L, eds. Nitric oxide in transplant rejection and anti-tumor defense. Boston: Kluwer Academic Publishers, 1998.
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Bonavida, Benjamin. Nitric Oxide (NO) and Cancer: Prognosis, Prevention, and Therapy. New York, NY: Springer Science + Business Media, LLC, 2010.
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Kenneth, Weir E., Archer Stephen L, and Reeves John T, eds. Nitric oxide and radicals in the pulmonary vasculature. Armonk, NY: Futura Pub. Co. Inc., 1996.
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Koutsoukos, Georgios. The regulation of metabolic coronary dilation and reactive hyperemia by nitric oxide in the isolated rat heart. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.
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Rauschmaier, Rüdiger. Nutzung von Nukleotiden und Nukleobasen als Wasserstoff und Kohlestoffquelle für die Denitrifikation. München: R. Oldenbourg, 1987.
Find full textBook chapters on the topic "Nitrite metabolism"
1
Kamin, H., and L. Stein Privalle. "Nitrite Reductase." In Inorganic Nitrogen Metabolism, 112–17. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_17.
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Wany, Aakanksha, Pradeep Kumar Pathak, and Kapuganti Jagadis Gupta. "Methods for Measuring Nitrate Reductase, Nitrite Levels, and Nitric Oxide from Plant Tissues." In Nitrogen Metabolism in Plants, 15–26. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9790-9_2.
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3
Hucklesby, D. P. "Nitrite Reduction in Leaf and Root." In Inorganic Nitrogen Metabolism, 123–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_19.
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Martinez, A., A. Alaña, M. J. Llama, and J. L. Serra. "Sustained Photoproduction of Ammonia from Nitrate or Nitrite by Free and Immobilized Cells of Phormidium laminosum." In Inorganic Nitrogen Metabolism, 220–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_45.
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Rajasekhar, V. K., and H. Mohr. "Appearance of Nitrite Reductase (NIR) and Nitrate Reductase (NR) in Cotyledons of the Mustard (Sinapis alba L.) Seedling as Affected by Nitrate, Ammonium, Phytochrome, and Photooxidative Damage of Plastids." In Inorganic Nitrogen Metabolism, 253–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_52.
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Meyer, Christian, and Christine Stöhr. "Soluble and Plasma Membrane-bound Enzymes Involved in Nitrate and Nitrite Metabolism." In Advances in Photosynthesis and Respiration, 49–62. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/0-306-48138-3_4.
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Cammack, R., I. V. Fry, and M. J. Payne. "The Significance of Iron-Nitrosyl Complexes in Biology and in the Reaction of Assimilatory Nitrite Reductase." In Inorganic Nitrogen Metabolism, 192–94. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_37.
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Siegel, L. M., J. O. Wilkerson, and P. A. Janick. "Structural Studies on the Siroheme [4Fe-4S] Cluster Active Centers of Spinach Ferredoxin-Nitrite Reductase and Escherichia coli Sulfite Reductase." In Inorganic Nitrogen Metabolism, 118–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71890-8_18.
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Takahashi, Misa, Michel Caboche, and Hiromichi Morikawa. "Is Nitrite Reductase Essential in the Metabolism of Nitrogen in Plants?" In Photosynthesis: Mechanisms and Effects, 3617–20. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_844.
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Schumacher, Wolfram, Frank Neese, Ursula Hole, and Peter M. H. Kroneck. "Cytochrome C Nitrite Reductase and Nitrous Oxide Reductase: Two Metallo Enzymes of the Nitrogen Cycle with Novel Metal Sites." In Transition Metals in Microbial Metabolism, 329–56. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003211129-12.
Full textConference papers on the topic "Nitrite metabolism"
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Seablom, Craig M., Lauren M. Frasier, Kathleen L. Falkner, and Anthony P. Pietropaoli. "Oxidative Stress Impairs Blood Nitrite Metabolism In Vitro." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a4958.
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Koch, C., V. Heinrich, R. Nettles, S. Qin, C. Sparacino-Watkins, K. Li, B. Methe, A. Fitch, and A. Morris. "Oral Microbiome Community Composition and Metabolism of Nitrate to Nitrite Are Driven by Individual Variation That Is Independent of Time." In American Thoracic Society 2019 International Conference, May 17-22, 2019 - Dallas, TX. American Thoracic Society, 2019. http://dx.doi.org/10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a3677.
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Rohma, Mila Riskiatul, Irfan Zubairi, Aldian Dwi Aryono, Lanang Nasrullah, and Desy Cahya Widianingrum. "Nitrat: karakteristik antinutrisi, dampak negatif, potensi aditif, dan efektivitas agen defaunasi." In The 2nd National Conference of Applied Animal Science (CAAS) 2021. Politeknik Negeri Jember, 2021. http://dx.doi.org/10.25047/animpro.2021.3.
Full textAbstract:
Kajian pustaka ini memberikan informasi karakteristik, dampak negatif, dan potensi aditif, dan efek positif dari penggunaan antinutrisi nitrat. Antinutrisi merupakan komponen senyawa metabolit sekunder yang terkandung di dalam tanaman dan dapat membahayakan ternak. Dampak negatif dari nitrat diantaranya keracunan pada ternak akibat reduksi nitrat dalam darah membentuk methamoglobin (MetHb) dan berpotensi menyebabkan keguguran pada ternak bunting akibat hypoxia. Meskipun demikian, nitrat dalam konsentrasi rendah dapat digunakan sebagai aditif pakan dan berdampak positif bagi produktifitas ternak. Pemanfaatan nitrat dalam bahan pakan hijauan bermanfaat sebagai agen defaunasi pada rumen ternak ruminansia. Penurunan populasi protozoa dalam rumen dapat meningkatkan kecernaan serat kasar sehingga bersifat menguntungkan karena terjadinya efisiensi produksi dan meningkatnya pertumbuhan ternak. Efek positif bagi lingkungan dengan adanya defaunasi adalah menurunkan emisi gas metan sebagai hasil dari proses metabolisme ternak ruminansia. Kesimpulan dari tulisan ini adalah senyawa antinutrisi pada pakan disamping memiliki dampak negatif, juga besar kemungkinan memiliki potensi yang dapat dimanfaatkan baik bagi ternak maupun lingkungan.
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Zaprudnova, Elena, Svetlana Soodaeva, Igor Klimanov, Timur Li, Nataliya Popova, Mary Glukhova, and Lidiya Nikitina. "Influence of exercise on the nitric oxide metabolism in young smokers." In Annual Congress 2015. European Respiratory Society, 2015. http://dx.doi.org/10.1183/13993003.congress-2015.pa3912.
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Batasheva, S. N. "Nitric oxide at the crossroads of metabolic pathways." In IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-58.
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Belova, Y. I., and O. V. Yakovleva. "Analysis of the content of nitric oxide (II) metabolites rats of different ages." In VIII Vserossijskaja konferencija s mezhdunarodnym uchastiem «Mediko-fiziologicheskie problemy jekologii cheloveka». Publishing center of Ulyanovsk State University, 2021. http://dx.doi.org/10.34014/mpphe.2021-27-29.
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Nitrogen monoxide is a gas transmitter that is an important intermediary in many organ systems, especially in the central nervous system. Nitrogen monoxide is involved in the relaxation of smooth vascular muscles, activation of neurons and responsible for the cytotoxicity of macrophages. The study of change nitrogen oxide metabolite concentration helps to determine its effects on human and animal organs. The study was carried out on laboratory animals of different ages. We used a spectrophotometric method to determine the level of metabolites based on the reaction of nitrites to the Griss reagent. We noted that the maximum level of metabolites NO was observed in newborn animals at the age of 4 days. In addition, metabolite concentrations decreased gradually by 14-15 days of life, reaching a minimum of 30 days
Key words: nitrogen monoxide, rats, age, metabolites of nitrogen monoxide, spectrophotometry.
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Caneba, Christine A., Juan Marini, and Deepak Nagrath. "Abstract 2920: Effect of nitric oxide on invasiveness and metabolism of cancer cells." In Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC. American Association for Cancer Research, 2013. http://dx.doi.org/10.1158/1538-7445.am2013-2920.
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Farkhutdinov, Usman, Elmira Amirova, and Rafagat Farkhutdinov. "Community acquired pneumonia in COPD patients: ?linical features and peculiarities of nitric oxide metabolism." In ERS International Congress 2021 abstracts. European Respiratory Society, 2021. http://dx.doi.org/10.1183/13993003.congress-2021.pa718.
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Oldham, William M., Gregory D. Lewis, Allison J. Janocha, Robert Naples, Paul Pappagianopoulos, Aaron Waxman, Serpil C. Erzurum, and David Systrom. "Nitric Oxide Pathway Metabolite Flux In Exercise-Induced Pulmonary Arterial Hypertension." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a6736.
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"Diversity and possible metabolic activity of the microbial community in nitrate- and radionuclide-contaminated groundwater." In Bioinformatics of Genome Regulation and Structure/Systems Biology (BGRS/SB-2022) :. Institute of Cytology and Genetics, the Siberian Branch of the Russian Academy of Sciences, 2022. http://dx.doi.org/10.18699/sbb-2022-287.
Full textReports on the topic "Nitrite metabolism"
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Fridman, Eyal, Jianming Yu, and Rivka Elbaum. Combining diversity within Sorghum bicolor for genomic and fine mapping of intra-allelic interactions underlying heterosis. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597925.bard.
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Heterosis, the enigmatic phenomenon in which whole genome heterozygous hybrids demonstrate superior fitness compared to their homozygous parents, is the main cornerstone of modern crop plant breeding. One explanation for this non-additive inheritance of hybrids is interaction of alleles within the same locus. This proposal aims at screening, identifying and investigating heterosis trait loci (HTL) for different yield traits by implementing a novel integrated mapping approach in Sorghum bicolor as a model for other crop plants. Originally, the general goal of this research was to perform a genetic dissection of heterosis in a diallel built from a set of Sorghum bicolor inbred lines. This was conducted by implementing a novel computational algorithm which aims at associating between specific heterozygosity found among hybrids with heterotic variation for different agronomic traits. The initial goals of the research are: (i) Perform genotype by sequencing (GBS) of the founder lines (ii) To evaluate the heterotic variation found in the diallel by performing field trails and measurements in the field (iii) To perform QTL analysis for identifying heterotic trait loci (HTL) (iv) to validate candidate HTL by testing the quantitative mode of inheritance in F2 populations, and (v) To identify candidate HTL in NAM founder lines and fine map these loci by test-cross selected RIL derived from these founders. The genetic mapping was initially achieved with app. 100 SSR markers, and later the founder lines were genotyped by sequencing. In addition to the original proposed research we have added two additional populations that were utilized to further develop the HTL mapping approach; (1) A diallel of budding yeast (Saccharomyces cerevisiae) that was tested for heterosis of doubling time, and (2) a recombinant inbred line population of Sorghum bicolor that allowed testing in the field and in more depth the contribution of heterosis to plant height, as well as to achieve novel simulation for predicting dominant and additive effects in tightly linked loci on pseudooverdominance. There are several conclusions relevant to crop plants in general and to sorghum breeding and biology in particular: (i) heterosis for reproductive (1), vegetative (2) and metabolic phenotypes is predominantly achieved via dominance complementation. (ii) most loci that seems to be inherited as overdominant are in fact achieving superior phenotype of the heterozygous due to linkage in repulsion, namely by pseudooverdominant mechanism. Our computer simulations show that such repulsion linkage could influence QTL detection and estimation of effect in segregating populations. (iii) A new height QTL (qHT7.1) was identified near the genomic region harboring the known auxin transporter Dw3 in sorghum, and its genetic dissection in RIL population demonstrated that it affects both the upper and lower parts of the plant, whereas Dw3 affects only the part below the flag leaf. (iv) HTL mapping for grain nitrogen content in sorghum grains has identified several candidate genes that regulate this trait, including several putative nitrate transporters and a transcription factor belonging to the no-apical meristem (NAC)-like large gene family. This activity was combined with another BARD-funded project in which several de-novo mutants in this gene were identified for functional analysis.