No description available.

The vermicomposting of coffee grounds shows great promise for urban areas and university campuses. Several studies have examined using coffee grounds as a substrate for vermicomposting, however, little is known about its effect on plant growth, yield and quality. Therefore, two studies were conducted to assess these effects on greenhouse spinach and field grown bell peppers. Coffee vermicompost (VC) was utilized in a greenhouse spinach study over two spring growing seasons (2011 and 2012). Coffee VC was added to a 1:1:1 (peat, soil, sand) medium by volume (0, 25, 50 and 75%) in 4.5 L clay pots and seeded with `Bloomsdale Longstanding' spinach (Spinacia oleracea). Growth parameters evaluated were fresh leaf weight (FLW), leaf area (LA), spinach plant height, number of leaves, fresh leaf ascorbic acid (AA) and dry leaf nitrate (DLN). In 2011, the highest FLW, LA, number of leaves, AA and nitrate content were seen at the 75% VC application rate. Many parameters were correlated: The FLW and the VC application rate (r=0.41, P<0.0001); the AA content in leaves and the VC application rate (r=0.60, P<0.0001); and the AA and nitrate content in leaves (r=0.45, P=0.011). In 2012, the greatest FLW, height and number of leaves were observed at the 50% VC application rate; the highest nitrate content at 75% VC application rate, with no difference in AA content. A field study was conducted over three seasons (2009–-2011) to compare four treatments (coffee VC, dairy compost, standard fertility (SFT) and no treatment) for their effects on growth, yield, and AA content of bell peppers. Coffee VC and dairy compost were applied to beds at the rate of 22 t/ha and SFT was applied as 212 kg/ha 12:12:12 (N:P:K). Parameters evaluated were total number and weight of marketable and cull (unmarketable) pepper fruits, plant height, leaf chlorophyll index, and fresh fruit AA content. There were no differences detected for pepper fruit yields or AA content, however, plant height and chlorophyll index were greater for the VC and SFT treatments than for the compost and control treatments. These results indicated that coffee VC can improve the yield of greenhouse spinach and that the AA content does not decrease with higher VC application rates, even as nitrate content increases. Results of the bell pepper field study indicated that the coffee VC treatment produces similar growth, yield and AA content as SFT.

The metabolism of plants grown in the cultivation medium is influenced by its composition and availability of CO2. In this project the effect of cultivation medium on the activity phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), NADP-malic enzyme (NADP-ME, EC 1.1.1.40), pyruvate, phosphate dikinase (PPDK, EC 2.7.9.1) and enzymes of nitrogen metabolism: nitrate reductase (NR, EC 1.7.1.1), glutamine synthetase (GS, EC 6.3.1.2), glutamate synthase (GOGAT, EC 1.4.1.13) and glutamate dehydrogenase (GDH, EC 1.4.1.2) was studied. The tobacco plant Nicotiana tabacum L., cv. Petit Havana SR1 were grown in vitro in containers fitted with a filter, which caused limited access of CO2. The cultivation medium was modified Murashige-Skoog agar with decreased amounts of phosphate, nitrate, ammonium, or with casein as source of nitrogen and with or without of 1.5% sucrose as additional carbon source Activity of PEPC was higher in plants grown in medium in the presence of sucrose. Reduced concentrations of phosphates, nitrates or NH4 + ions or when casein was the only source of N in medium caused decreased activity of PEPC. Under these conditions, also activity of NADP-ME and of enzymes of nitrogen metabolism: NR, GS decreased. Activity of all enzymes was also negatively affected by limited CO2. On the other...

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-14T12:46:20Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_Danielli Batista Bezerra Cajueiro.pdf: 1520169 bytes, checksum: 01f947c81a685b7a391d5c6dbfcf83bd (MD5) / Made available in DSpace on 2017-02-14T12:46:20Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_Danielli Batista Bezerra Cajueiro.pdf: 1520169 bytes, checksum: 01f947c81a685b7a391d5c6dbfcf83bd (MD5) Previous issue date: 2015-06-12 / CAPES / As fontes de nitrogênio do meio são classificadas como preferenciais e nãopreferenciais, de maneira que as primeiras inibem a expressão dos genes responsáveis pela metabolização das segundas por um mecanismo chamado de Repressão Catabólica do Nitrogênio (Nitrogen Catabolic Repression - NCR). No presente estudo avaliamos o padrão de regulação dos genes do metabolismo central do nitrogênio na levedura Dekkera bruxellensis. Foram definidos quatro grupos de fontes de nitrogênio baseados no crescimento celular. Em seguida, o padrão de expressão dos genes do metabolismo central do nitrogênio mostrou que fenilalanina, embora do grupo quatro, é o maior indutor das permeases Gap1p e Put4p, resultando em sua elevada taxa de consumo. Já a histidina, indutora da permease Put4p, promove maior indução dos genes que codificam as enzimas de assimilação de amônia. Quando o mecanismo NCR é inibido pela presença de metionina sulfoximina no meio, ocorre a desrrepressão dos genes que codificam as permeases. E finalmente, os resultados mostram que nitrato, definido no grupo dois induz o mecanismo de sinalização intracelular de regulação gênica semelhante ao que se observa quando as células estão no estado de privação de nitrogênio no meio. Isto complementa os estudos anteriores nos quais mostramos que a assimilação de nitrato altera o estado fisiológico da célula para respiração mesmo na presença de alta concentração de glicose no meio. / The nitrogen sources in the medium are classified as preferential or non-preferrential, so that the first inhibit expression of genes responsible for metabolism of the latter by a mechanism called Nitrogen Catabolic Repression (NCR). In the present study we evaluated the pattern of gene regulation of the central nitrogen metabolism in yeast Dekkera bruxellensis. It was defined four groups of nitrogen sources based on cell growth. Then, the expression pattern of the central nitrogen metabolism genes showed that phenylalanine, though belonging to group four, is the biggest inducer of genes of permeases Gap1p Put4p, resulting in its high consumption rate. Moreover, histidine induces the gene encoding permease Put4p and promoted the highest induction of the genes encoding the enzymes of ammonia assimilation. When the NCR mechanism was inhibited by the presence of methionine sulfoximine in the medium there was derepression of the genes encoding for permeases. Finally, the results showed that nitrate, defined in the group two, induced the intracellular signaling pathway gene regulation similar to that seen when cells are in a state of nitrogen deprivation in the middle. This complements our previous studies that showed that the nitrate assimilation alter the physiological state of the cell to respiration even in presence of high glucose concentration in medium.

The initiation, persistence, and termination of harmful algal blooms (HABs) can all be influenced by nutrient availability. Recent studies have highlighted the role of both organic and inorganic nitrogen sources in HAB dynamics. The pelagophyte Aureoumbra lagunensis causes ecosystem disruptive algal blooms and is responsible for the longest recorded harmful algal bloom (1989-1997). Because of Aureoumbra's small size and its inability to use nitrate, it has been hypothesized that its ability to use ammonium and organic nitrogen, especially at low concentrations, contributed to the unusual persistence of this bloom. This project aimed to assess the response of Aureoumbra to inorganic and organic nitrogen sources by examining the expression of genes responsible for nitrogen assimilation, with an eventual intent of developing expression assays that are indicative of nitrogen source use and/or sufficiency in Aureoumbra. Large volume batch cultures of Aureoumbra were grown with either ammonium or urea as a nitrogen source. Physiological characteristics (C:N, chlorophyll [alpha] cell⁻¹, and Fv/Fm) were monitored throughout the growth period, and the expression of the AMT-1, AMT-2 and UREC genes was assayed at early-, mid- and late-exponential phases. The results show that Aureoumbra can use both ammonium and urea, and that it is well adapted to low-nutrient environments. Only one gene, AMT-1, appeared to be transcriptionally regulated in response to changing nitrogen concentration, and only to ammonium. The results of this study contribute to our understanding of how algae in general cope with low nutrient availability and should ultimately help to define the dynamics of these HAB events. / text

No description available.

Παρά τη σημαντική της συνεισφορά στο συνολικό κέρδος σε άνθρακα των φυτών και τις λειτουργικές της ιδιαιτερότητες, η φωτοσύνθεση βλαστού δεν έχει μελετηθεί στην έκταση που της αναλογεί. Για το λόγο αυτό εφαρμόσαμε ένα συνδυασμό ανατομικών και φυσιολογικών μεθόδων για το χαρακτηρισμό του φωτοσυνθετικού μηχανισμού των πράσινων μίσχων και των στελεχών του άνθους του μονοκοτυλήδονου γεώφυτου Zantedeschia aethiopica και των πράσινων βλαστών του δικοτυλήδονου ημιξυλώδους Dianthus caryophyllus, σε σύγκριση με τα αντίστοιχα φύλλα. Οι μίσχοι και τα στελέχη του άνθους του Z. aethiopica και οι βλαστοί του D. caryophyllus διαθέτουν όλα τα ανατομικά χαρακτηριστικά ενός φωτοσυνθετικά αποδοτικού οργάνου, όπως σημαντικό αριθμό στομάτων με τυπικούς υποστομάτιους θαλάμους, χλωρεγχυματικά κύτταρα παρόμοιας μορφολογίας με τα δρυφακτοειδή κύτταρα των φύλλων, επαρκείς μεσοκυττάριους χώρους και σημαντικό ποσοστό ελεύθερων κυτταρικών τοιχωμάτων. Ωστόσο, η διάταξη των δρυφακτοειδών κυττάρων των μίσχων/στελεχών του Z. aethiopica είναι ασυνήθιστη, καθώς διευθετούνται παράλληλα με τον κατά μήκος άξονα των οργάνων. Επιπλέον, οι μίσχοι/στελέχη επέδειξαν φωτοσυνθετικά χαρακτηριστικά που προσομοιάζουν με εκείνα φύλλων σε συνθήκες καταπόνησης, όπως μειωμένο περιεχόμενο/ενεργότητα της Rubisco, αυξημένο ρυθμό του κύκλου C2 και αυξημένη κυκλική ροή ηλεκτρονίων γύρω από το PSI. Τα χαρακτηριστικά αυτά φαίνεται πως είναι εγγενή στα συγκεκριμένα φωτοσυνθετικά όργανα, εξυπηρετώντας την αυξημένη αζωτοδεσμευτική ικανότητα του είδους, την ποιοτική ρύθμιση του περιεχομένου τους σε αμινοξέα, την αποκαρβοξυλίωση C4-οργανικών οξέων του διαπνευστικού ρεύματος και την ταχεία επαγωγή της μη-φωτοχημικής απόσβεσης. Σε αντίθεση με το Z. aethiopica, η φωτοσυνθετική απόδοση των βλαστών του D. caryophyllus βρέθηκε ανώτερη αυτής των φύλλων, ως αποτέλεσμα των υψηλότερων ρυθμών του κύκλου C3 και μιας πιθανής οργανο-ειδικής ποικιλότητας του παράγοντα εξειδίκευσης της Rubisco. Η μειωμένη ένταση του προσπίπτοντος φωτός in vivo, λόγω του κάθετου προσανατολισμού των βλαστών, ενδεχομένως να οδηγεί σε χαμηλότερα επίπεδα φωτοπροστασίας σε σύγκριση με τα φύλλα και στην υιοθέτηση μιας στρατηγικής βελτιστοποίησης του ρυθμού καθήλωσης C, η οποία πιθανώς περιλαμβάνει και την καθήλωση CO2, που προέρχεται από την αποκαρβοξυλίωση C4-οργανικών οξέων του διαπνευστικού ρεύματος. / Despite its significant contribution to the net carbon gain of plants and its distinct functional properties, stem photosynthesis has not yet received adequate scientific attention. For this reason, a combination of anatomical and physiological methods was used to characterize the photosynthetic machinery of the green petioles and pedicels of the monocotyledonous geophyte Zantedeschia aethiopica and the green stems of the dicotyledonous semi-woody species Dianthus caryophyllus, in comparison to the corresponding leaves. Both the green petioles/pedicels of Z. aethiopica and the green stems of D. caryophyllus possess all the anatomical prerequisites of an actively photosynthesizing organ i.e. considerable number of stomata with typical underlying substomatal chambers, chlorenchyma cells which are similar to the leaf palisade chlorenchyma cells and considerable amount of both intercellular spaces and palisade free cell walls. Yet, the palisade cells of Z. aethiopica petioles/pedicels show a peculiar arrangement with their long axis parallel to the longitudinal organ axis. Furthermore, petiole/pedicel photosynthetic characteristics resemble those of leaves under adversity i.e. reduced Rubisco activity/content, high photorespiration rates and significant cyclic electron flow around PSI. It is concluded that these are innate attributes of petiole/pedicel photosynthesis serving particular functions like the increased nitrogen fixing activity of the species, the qualitative adjustment of the petiole/pedicel amino acid content, the active decarboxylation of C4-organic acids and the rapid induction of non-photochemical quenching. Stem photosynthesis in D. caryophyllus was more efficient than leaf photosynthesis, as a result of the greater rates of stem C3 cycle and a possible organ-specific variation of the specificity factor of Rubisco. In general, D. caryophyllus stems display a photosynthetic pattern of optimal carbon assimilation in the expense of photoprotection. It could be hypothesized that this kind of adaptation could be due to the vertical orientation of stems, which results in lower incident light intensities in vivo and may include the use of C4-organic acids coming up with the transpiration stream as an additional carbon source.

Made available in DSpace on 2016-04-26T19:39:29Z (GMT). No. of bitstreams: 1 2007-Andre Marques dos Santos.pdf: 1289315 bytes, checksum: 28a3126a64acf0f1d9ab8338c8a0ac19 (MD5) Previous issue date: 2007-02-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Rice is one of the most important cereals for the humanity, because it is primary source of nutrition for more than half of the world s population. Nitrogen is the most important element for plants and is predominantly present in aerated soils in the nitrate form. As a result of the poor quality of the cultivated areas, the usage of nitrogen fertilizers intensified, contributing to the increase of pollution, since this nutrient has high mobility in the soil. With the objective of evaluating physiologic, biochemical and molecular mechanisms responsible for the efficiency of the application of nitrogen in rice, experiments were conducted at the Soils Department of Federal Rural University of Rio de Janeiro. Two rice varieties were used, Piaui (traditional rice) and IAC-47 (improved rice). In the beginning, both varieties were cultivated in nutrition solutions and submitted to treatments simulating the seasonal fluctuation of nitrate, characteristic of the tropical region. Under this condition an evaluation was done in order to define the soluble sugar levels, nitrogen fractions, and the Nitrate Reductase Activity (NRA) as well as Glutamine Synthetase Activity. Piaui rice was more efficient in the acquisition and usage of nitrogen compared to IAC-47, accumulating nitrate in its tissue during the initial phase of growth for future consumption. Later, these same rice varieties were cultivated in a growth chamber with the objective of studying the effect of increased nitrate concentrations over nitrogen fraction levels, NRA, relative expression of genes for nitrate transporters (NRT1 and NRT2) as well as a nitrate reductase (Nia2). From the results obtained it was observed that the traditional rice variety contained less NRA, higher levels of nitrogen and free amino-N. Further, traditional variety presented higher relative expression of the genes which codify nitrate transporters of low affinity (NRT1) and those of high affinity (NRT2). These plants seemed to adopt a differentiated control of NRA, because even having a higher relative expression of the genes, the NRA maintained practically without influence from the different concentrations of nitrate in the solution. In the last experiment, genes in the tips of rice roots were identified, induced by different concentrations of nitrate (0.1 and 10 mM). Several genes were sequenced, were the most important data was the subunit E1 of the dehydrogenase pyruvate complex, and phosphofructokinase, suggesting the need for a better understanding of the complexity of the interaction between carbon and nitrogen metabolism. There were also found sequences homologous to the alpha actin, myosin, tropomyosin 1, creatin kinase, and glyoxalase I genes. / O arroz ? um dos mais importantes cereais para o homem, porque ? fonte prim?ria na alimenta??o de mais da metade da popula??o do mundo. As plantas necessitam de nitrog?nio para seu desenvolvimento, sendo este presente em solos aerados, na forma de nitrato. Em fun??o do desgaste das ?reas cultivadas, tem sido intensificada a utiliza??o de fertilizantes nitrogenados, o que contribui para o aumento da polui??o, visto que, esse composto possui grande mobilidade no solo. Objetivando-se avaliar os mecanismos fisiol?gicos, bioqu?micos e moleculares respons?veis pela efici?ncia no uso de nitrog?nio em arroz foram conduzidos tr?s experimentos no Departamento de Solos da Universidade Federal Rural do Rio de Janeiro, com duas variedades de arroz, uma tradicional (Piau?) e outra melhorada (IAC-47). Primeiramente, ambas as variedades foram cultivadas em solu??o nutritiva e submetidas a tratamentos simulando o fluxo sazonal de nitrato, caracter?stico das regi?es tropicais. Nessa condi??o, foram avaliados os teores de a??cares sol?veis, fra??es nitrogenadas e a atividade das enzimas Nitrato Redutase (ANR) e Glutamina Sintetase. A variedade Piau? foi mais eficiente na aquisi??o e uso do N quando comparada a IAC-47, acumulando nitrato em seus tecidos durante as fases iniciais de crescimento. Depois, essas mesmas variedades foram cultivadas em c?mara de crescimento para estudar o efeito de concentra??es crescentes de nitrato sobre os teores das fra??es nitrogenadas, ANR e sobre o perfil de express?o relativa dos genes dos transportadores de nitrato (NRT1 e NRT2) e da Nitrato Redutase (Nia2). Dos resultados obtidos, foi observado que a variedade tradicional possui menor ANR, maiores teores de nitrato e N-amino livre. Al?m disso, esta apresentou maior express?o relativa dos genes que codificam os transportadores de nitrato de baixa (NRT1) e os de alta (NRT2) afinidade, sendo esse na parte a?rea. Estas plantas pareceram adotar um controle diferenciado da ANR, pois mesmo tendo maior express?o relativa desse gene, a atividade desta enzima se mant?m praticamente sem sofrer influ?ncia das concentra??es de nitrato na solu??o. No ?ltimo experimento, foram identificados os genes induzidos por duas concentra??es de nitrato (0,1 e 10 mM) em ?pices radiculares de arroz. Diversos genes foram seq?enciados, dentre eles, destacou-se a subunidade E1 do complexo piruvato desidrogenase e fosfofrutoquinase, indicando a necessidade de se melhor entender a complexidade da intera??o entre o metabolismo de carbono e nitrog?nio. Foram encontradas tamb?m seq??ncias hom?logas aos genes da alfa actina, miosina, tropomiosina 1, creatina cinase e glioxalase I.

Ce projet a pour but d’évaluer la capacité de la voie des pentoses phosphates (VPP) dans les racines transgéniques de pomme de terre (Solanum tuberosum) modifiées pour exprimer différents niveaux de l'hexokinase (HK) et de la triosephosphate isomérase cytosolique (cTPI). Dans les racines, la VPP alimente la voie de l’assimilation de l’azote en equivalents réducteurs et permet donc la biosynthèse des acides aminés. Le glucose-6-phosphate produit par l’HK est consommé par la partie oxydative de la VPP catalysée par la glucose-6-phosphate déshydrogénase (G6PDH) et la 6-phosphogluconate déshydrogénase (6PGDH). Les changements dans l'expression de HK et cTPI peuvent affecter le fonctionnement de la VPP et les mécanismes qui sont liés à l’utilisation des équivalents réducteurs produits par la VPP, comme l'assimilation de l’azote et la synthèse des acides aminés. Afin d’évaluer l’effet des manipulations génétiques de l’HK et de la cTPI sur l’assimilation de l’azote, nous avons cultivé les racines transgéniques sur des milieux contenant des concentrations élevées (7 mM) ou basses (0,7 mM) de nitrate d’ammonium comme source d’azote. Les résultats montrent que la culture sur un milieu riche en azote induit les activités G6PDH et 6PGDH. Les données montrent que la capacité de la VPP est plus grande avec des niveaux élevés en HK ou en cTPI. Nous avons aussi pu démontrer une plus grande activité spécifique de l’HK dans les conditions pauvres en azote. Ces données ont été complémentées par des mesures des pools d’acides aminés dans les racines transgéniques cultivées sur différents niveaux d’azote. Aucune tendance notable des pools d’acides aminés n’a été remarquée dans les racines modifiées pour leur contenu en HK suggèrant que la manipulation de HK n’affecte pas l'assimilation de l’azote. Dans les racines transgéniques modifiées pour la cTPI, les ratios Gln/Glu et Asn/Asp sont plus élevés chez les clones antisens, indiquant une assimilation de l’azote plus élevée. Ces résultats ont démontré l'activation de l'assimilation de l’azote chez les clones antisens cTPI dans les conditions élevées et basses d’azote alors que la manipulation de l’HK n’affecte pas l’assimilation de l’azote. / This study investigates the capacity of the oxidative pentose phosphate pathway (oxPPP) and nitrogen metabolism in transgenic potato (Solanum tuberosum) roots modified to express different levels of hexokinase (HK) or cytosolic triosephosphate isomerase (cTPI) growing under different nitrogen regimes. The flux of carbon through the oxPPP in cTPI antisense roots is higher than control roots growing under high supply of N. On the other hand, the conversion of Glucose (Glc) to Glucose-6-phosphate (G6P) is higher in roots overexpressing HK than in antisense HK roots growing at a high level of N. Therefore, overexpression of HK or down regulation of cTPI activities in transgenic roots might be compensated by increased C catabolism through the oxPPP. In order to see the affect of HK and cTPI manipulation on N assimilation, the transgenic roots were grown on media with low or high concentration of ammonium nitrate as the N source. The specific activity of the oxPPP enzymes glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were both increased by an increased N supply in HK and cTPI transgenic roots. This is consistent with the provision of reducing equivalents for N assimilation. The data also show that the capacity of the oxPPP is higher in roots with high HK or cTPI activity. We were able to detect higher HK specific activity in N deficient conditions. These data were complemented with measurements of amino acid pools in transgenic roots. No trend in amino acid pools was found in roots modified for HK activity. However, down regulation of cTPI led to higher Gln, Gln/Glu and Asn/Asp ratios, indicating higher assimilation of N. These results demonstrated the activation of N assimilation in cTPI antisense clones while the manipulation of HK is unlikely to affect the N assimilation.

No description available.