scholarly journals Role of de novo biosynthesis in ecosystem scale monoterpene emissions from a boreal Scots pine forest

2011 ◽  
Vol 8 (8) ◽  
pp. 2247-2255 ◽  
Author(s):  
R. Taipale ◽  
M. K. Kajos ◽  
J. Patokoski ◽  
P. Rantala ◽  
T. M. Ruuskanen ◽  
...  
Keyword(s):  
Scots Pine ◽  
De Novo ◽  
Proton Transfer Reaction ◽  
Eddy Covariance Method ◽  
De Novo Biosynthesis ◽  
Monoterpene Biosynthesis ◽  
Monthly Changes ◽  
Scots Pine Forest ◽  
Storage Pools

Abstract. Monoterpene emissions from Scots pine have traditionally been assumed to originate as evaporation from specialized storage pools. More recently, the significance of de novo emissions, originating directly from monoterpene biosynthesis, has been recognized. To study the role of biosynthesis at the ecosystem scale, we measured monoterpene emissions from a Scots pine dominated forest in southern Finland using the disjunct eddy covariance method combined with proton transfer reaction mass spectrometry. The interpretation of the measurements was based on a correlation analysis and a hybrid emission algorithm describing both de novo and pool emissions. During the measurement period May–August 2007, the monthly medians of daytime emissions were 200, 290, 180, and 200 μg m−2 h−1. The emissions were partly light dependent, probably due to de novo biosynthesis. The emission potential for both de novo and pool emissions exhibited a decreasing summertime trend. The ratio of the de novo emission potential to the total emission potential varied between 30 % and 46 %. Although the monthly changes were not significant, the ratio always differed statistically from zero, suggesting that the role of de novo biosynthesis was observable. Given the uncertainties in this study, we conclude that more accurate estimates of the contribution of de novo emissions are required for improving monoterpene emission algorithms for Scots pine dominated forests.

scholarly journals Role of de novo biosynthesis in ecosystem scale monoterpene emissions from a boreal Scots pine forest

2010 ◽  
Vol 7 (6) ◽  
pp. 8019-8040 ◽  
Author(s):  
R. Taipale ◽  
M. K. Kajos ◽  
J. Patokoski ◽  
P. Rantala ◽  
T. M. Ruuskanen ◽  
...  
Keyword(s):  
Scots Pine ◽  
De Novo ◽  
Hybrid Approach ◽  
Proton Transfer Reaction ◽  
Eddy Covariance Method ◽  
De Novo Biosynthesis ◽  
Monoterpene Biosynthesis ◽  
Emission Modelling ◽  
Scots Pine Forest

Abstract. Monoterpene emissions from Scots pine have traditionally been assumed to originate as evaporation from specialized storage pools. More recently, the significance of de novo emissions, originating directly from monoterpene biosynthesis, has been recognized. To study the role of biosynthesis in the ecosystem scale, we measured monoterpene emissions from a Scots pine dominated forest in southern Finland using the disjunct eddy covariance method combined with proton transfer reaction mass spectrometry. The interpretation of the measurements was based on a hybrid emission algorithm describing both de novo and pool emissions. During the measurement period May–August 2007, the monthly medians of daytime emissions were 170, 280, 180, and 180 μg m−2 h−1. The emission potential for both de novo and pool emissions exhibited a decreasing summertime trend. The ratio of the de novo emission potential to the total emission potential varied between 30% and 46%. Although the monthly changes were not significant, the ratio always differed statistically from zero, i.e., the role of de novo biosynthesis was evident. The hybrid approach showed promising potential for the improvement of the ecosystem scale emission modelling. Given this feature and the significant role of biosynthesis, we recommend incorporating both de novo and pool emissions into the monoterpene emission algorithms for Scots pine dominated forests.

Regulation Of The Fatty Acid Composition Of Platelet Phospholipids

1981 ◽  
Author(s):  
M L McKean ◽  
J B Smith ◽  
M J Silver
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
Membrane Phospholipids ◽  
De Novo Biosynthesis ◽  
Coa Transferase

The fatty acid composition of cell membrane phospholipids does not remain constant after de novo biosynthesis, but undergoes continual remodelling. One of the major routes for remodelling probably includes the deacylation-reacylation steps of the Lands Pathway. This has been shown to be important for the incorporation of long chain, polyunsaturated fatty acids into phospholipids by liver and brain. An understanding of the mechanisms involved in these processes in platelets is especially important in light of the large stores of arachidonic acid (AA) in platelet phospholipids and the role of AA in hemostasis and thrombosis. Previous results from this laboratory have shown that the turnover of radioactive AA, 8,11,14-eicosatrienoic and 5,8,11,14,17-eicosapentaenoic acids in the phospholipids of resting platelets is more rapid than the turnover of radioactive C16 and C18 saturated and unsaturated fatty acids. However, little is known about how fatty acids, especially AA and its homologues, are incorporated into platelet phospholipids during de novo biosynthesis or how they are exchanged during remodelling.At least three enzymes are involved in the deacylation- reacylation of phospholipids: phospholipase A2; acyl CoA synthetase; and acyl CoA transferase. We have studied acyl CoA transferase and have found considerable activity in human platelet membranes. Experiments are in progress to determine the substrate specificity and other properties of this enzyme.

scholarly journals <sup>13</sup>C labelling study of constitutive and stress-induced terpenoide missions from Norway spruce and Scots pine

2017 ◽  
Author(s):  
Cheng Wu ◽  
Iida Pullinen ◽  
Stefanie Andres ◽  
Astrid Kiendler-Scharr ◽  
Einhard Kleist ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Atmospheric Chemistry ◽  
De Novo ◽  
Carbon Sources ◽  
Turnover Time ◽  
Co2 Uptake ◽  
Terpenoid Biosynthesis ◽  
Mva Pathway ◽  
Storage Pools

Abstract. Due to their large source strengths, biogenic volatile organic compounds (BVOCs) are important for atmospheric chemistry. Terpenoids, mainly consisting of isoprene, monoterpenes and sesquiterpenes, are the dominant BVOC class. There are two general mechanisms for their emissions: emissions directly from de novo biosynthesis (de novo emissions) and emissions from organs wherein the terpenoids are stored (pool emissions). While isoprene emissions are pure de novo emissions, the mechanism for monoterpene and sesquiterpene emissions is not always distinct. In particular, conifers have large storage pools and both mechanisms may contribute to the emissions. To obtain more insight into the mechanisms of the terpenoid emissions from Eurasian conifers, we conducted 13CO2 and 13C-glucose labelling studies with Norway spruce (Picea abies L.) and Scots pine (Pinus sylvestris L.). The results from the labelling experiments were further compared to diurnal modulations measured for the emission fluxes of the respective terpenoids, as well as to their release from reservoirs in needles and bark tissue. The comparison allowed the following comprehensive statements for the investigated conifers. Consistent to other studies, we found that constitutive monoterpene emissions mainly originate from storage pools but with compound-specific fractions of de novo emissions. In contrast, stress-induced monoterpene and sesquiterpene emissions are entirely of de novo nature. We also found at least three different carbon sources for monoterpene and sesquiterpene biosynthesis. These sources differ with respect to the timescale after which the recently assimilated carbon reappears in the emitted terpenoids. Carbon directly obtained from assimilated has a short turnover time of few hours, while carbon from other alternative carbon sources has intermediate turnover times of few days and even longer. Terpenoid biosynthesis is not restricted to the presence of light and the carbon for terpenoid biosynthesis can be delivered from the alternative carbon sources. In particular for sesquiterpenes, there can be substantial de novo emissions in darkness reaching up to around 60 % of the daytime emissions. The use of the alternative carbon sources for sesquiterpene synthesis is probably linked to the mevalonic acid (MVA) pathway. The higher the contribution of the MVA pathway to terpenoid synthesis, the higher is the nocturnal de novo emission. In general, the emission mechanisms of monoterpene and sesquiterpene are more complex than assumed so far. Besides pools for terpenoids themselves, there are also pools for terpenoids precursors. Terpenoid synthesis from alternative carbon sources leads to nighttime emissions and hence the amplitude of diurnal modulations of terpenoid emissions may be determined by an overlap of three mechanisms involved: emissions from storage pools, emissions in parallel to CO2 uptake and emissions from alternative carbon sources.

scholarly journals Importance of Trehalose Biosynthesis for Sinorhizobium meliloti Osmotolerance and Nodulation of Alfalfa Roots

2009 ◽  
Vol 191 (24) ◽  
pp. 7490-7499 ◽  
Author(s):  
Ana Domínguez-Ferreras ◽  
María J. Soto ◽  
Rebeca Pérez-Arnedo ◽  
José Olivares ◽  
Juan Sanjuán
Keyword(s):  
Sinorhizobium Meliloti ◽  
De Novo ◽  
The Other ◽  
Biosynthesis Pathway ◽  
De Novo Biosynthesis ◽  
Common Response ◽  
Trehalose Biosynthesis ◽  
Trehalose Synthesis ◽  
Trehalose Accumulation

ABSTRACT The disaccharide trehalose is a well-known osmoprotectant, and trehalose accumulation through de novo biosynthesis is a common response of bacteria to abiotic stress. In this study, we have investigated the role of endogenous trehalose synthesis in the osmotolerance of Sinorhizobium meliloti. Genes coding for three possible trehalose synthesis pathways are present in the genome of S. meliloti 1021: OtsA, TreYZ, and TreS. Among these, OtsA has a major role in trehalose accumulation under all of the conditions tested and is the main system involved in osmoadaptation. Nevertheless, the other two systems are also important for growth in hyperosmotic medium. Genes for the three pathways are transcriptionally responsive to osmotic stress. The presence of at least one functional trehalose biosynthesis pathway is required for optimal competitiveness of S. meliloti to nodulate alfalfa roots.

9 A NOVEL ROLE OF SPHINGOSINE KINASE 1 IN THE DE NOVO BIOSYNTHESIS OF DIHYDROSPHINGOSINE-1-PHOSPHATE IN MAMMALIAN CELLS.

2006 ◽  
Vol 54 (2) ◽  
pp. S345.3-S345
Author(s):  
E. Berdyshev ◽  
I. Gorshkova ◽  
P. Usatyuk ◽  
Y. Zhao ◽  
B. Saatian ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 1 ◽  
De Novo Biosynthesis

The role of acyl carrier protein isoforms from Cuphea lanceolata seeds in the de-novo biosynthesis of medium-chain fatty acids

Planta ◽  
1998 ◽  
Vol 205 (2) ◽  
pp. 263-268 ◽  
Author(s):  
Burkhardt Siegfried Schütt ◽  
Monika Brummel ◽  
Ricardo Schuch ◽  
Friedrich Spener
Keyword(s):  
Fatty Acids ◽  
De Novo ◽  
Acyl Carrier Protein ◽  
Protein Isoforms ◽  
Carrier Protein ◽  
Medium Chain ◽  
Medium Chain Fatty Acids ◽  
De Novo Biosynthesis ◽  
Cuphea Lanceolata

scholarly journals A Novel Role of Sphingosine Kinase 1 in the de novo Biosynthesis of Dihydrosphingosine‐1‐Phosphate in Mammalian Cells.

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
E. Berdyshev ◽  
I. Gorshkova ◽  
P. Usatyuk ◽  
Y. Zhao ◽  
B. Saatian ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 1 ◽  
De Novo Biosynthesis

Posttransplant CMV infection and the role of immunosuppression (Sponsor: Novartis Pharma GmbH, Nürnberg)

2016 ◽  
Vol 04 (01) ◽  
pp. 4-10
Keyword(s):  
Lower Incidence ◽  
Paradigm Shift ◽  
Mtor Inhibitor ◽  
De Novo ◽  
Expert Panel ◽  
Risk Of Infection ◽  
Cmv Infection ◽  
Expert Meeting ◽  
Selection Of

AbstractImmunosuppression permits graft survival after transplantation and consequently a longer and better life. On the other hand, it increases the risk of infection, for instance with cytomegalovirus (CMV). However, the various available immunosuppressive therapies differ in this regard. One of the first clinical trials using de novo everolimus after kidney transplantation [1] already revealed a considerably lower incidence of CMV infection in the everolimus arms than in the mycophenolate mofetil (MMF) arm. This result was repeatedly confirmed in later studies [2–4]. Everolimus is now considered a substance with antiviral properties. This article is based on the expert meeting “Posttransplant CMV infection and the role of immunosuppression”. The expert panel called for a paradigm shift: In a CMV prevention strategy the targeted selection of the immunosuppressive therapy is also a key element. For patients with elevated risk of CMV, mTOR inhibitor-based immunosuppression is advantageous as it is associated with a significantly lower incidence of CMV events.

Typology of the natural regeneration in a middle-aged Scots pine forest

1988 ◽  
Vol 53 ◽  
Author(s):  
C. De Schepper
Keyword(s):  
Scots Pine ◽  
Natural Regeneration ◽  
Free Field ◽  
Sandy Soils ◽  
Structural Basis ◽  
Pedunculate Oak ◽  
Pine Stands ◽  
Scots Pine Forest ◽  
Forest Practice ◽  
Scots Pine Stands

The  study describes the natural regeneration state of a forest on coarse sandy  soils. The natural regeneration was studied in three different ecological  conditions: in 30 to 60 year old Scots pine stands, in a 62 year old mixed  stand of pedunculate oak and red oak, and on the free field.     The analysis of the regeneration groups revealed that the first settler  maintained a dominant social position during the following years after the  settlement. The structural basis is consequently laid out early. This means  that the forest practice has to consider the very first phase of the  regeneration as determining for the following evolution of the regeneration  groups.

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