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.

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.

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 Ceramide Suppresses Influenza A Virus Replication In Vitro

2019 ◽  
Vol 93 (7) ◽  
Author(s):  
Nadia Soudani ◽  
Rouba Hage-Sleiman ◽  
Walid Karam ◽  
Ghassan Dbaibo ◽  
Hassan Zaraket
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
De Novo ◽  
Dependent Manner ◽  
Biosynthesis Pathway ◽  
Influenza A H1n1 ◽  
Ceramide Accumulation ◽  
Antiviral Role

ABSTRACT Annual influenza outbreaks are associated with significant morbidity and mortality worldwide despite the availability of seasonal vaccines. Influenza pathogenesis depends on the manipulation of host cell signaling to promote virus replication. Ceramide is a sphingosine-derived lipid that regulates diverse cellular processes. Studies highlighted the differential role of ceramide de novo biosynthesis on the propagation of various viruses. Whether ceramide plays, a role in influenza virus replication is not known. In this study, we assessed the potential interplay between the influenza A (IAV) and ceramide biosynthesis pathways. The accumulation of ceramide in human lung epithelial cells infected with influenza A/H1N1 virus strains was evaluated using thin-layer chromatography and/or confocal microscopy. Virus replication was assessed upon the regulation of the de novo ceramide biosynthesis pathway. A significant increase in ceramide accumulation was observed in cells infected with IAV in a dose- and time-dependent manner. Inoculating the cells with UV-inactivated IAV did not result in ceramide accumulation in the cells, suggesting that the induction of ceramide required an active virus replication. Inhibiting de novo ceramide significantly decreased ceramide accumulation and enhanced virus replication. The addition of exogenous C6-ceramide prior to infection mediated an increase in cellular ceramide levels and significantly attenuated IAV replication and reduced viral titers (≈1 log10 PFU/ml unit). Therefore, our data demonstrate that ceramide accumulation through de novo biosynthesis pathway plays a protective and antiviral role against IAV infection. These findings propose new avenues for development of antiviral molecules and strategies. IMPORTANCE Understanding the effect of sphingolipid metabolism on viral pathogenesis provide important insights into the development of therapeutic strategies against microbial infections. In this study, we demonstrate a critical role of ceramide during influenza A virus infection. We demonstrate that ceramide produced through de novo biosynthesis possess an antiviral role. These observations unlock new opportunities for the development of novel antiviral therapies against influenza.

scholarly journals Phytophthora capsici sterol reductase PcDHCR7 has a role in mycelium development and pathogenicity

2021 ◽  
Author(s):  
Weizhen Wang ◽  
Fan Zhang ◽  
Sicong Zhang ◽  
Zhaolin Xue ◽  
Linfang Xie ◽  
...  
Keyword(s):  
De Novo ◽  
Reductase Activity ◽  
Phytophthora Capsici ◽  
Biosynthesis Pathway ◽  
Wild Type ◽  
Knock Out ◽  
Type Isolate ◽  
De Novo Biosynthesis ◽  
Phytophthora Spp ◽  
Genes Encoding

The de novo biosynthesis of sterols is critical for eukaryotes, however, some organisms lack this pathway including most oomycetes. Phytophthora spp. are sterol auxotroph but remarkably, have retained a few genes encoding enzymes in the sterol biosynthesis pathway. Here we investigated the function of PcDHCR7, a gene in Phytophthora capsici predicted to encode the Δ7-sterol reductase. When expressed in Saccharomyces cerevisiae, PcDHCR7 showed a Δ7-sterol reductase activity. Knocking out PcDHCR7 in P. capsici resulted in loss of the capacity to transform ergosterol into brassicasterol, which means PcDHCR7 has a Δ7-sterol reductase activity in P. capsici itself. This enables P. capsici to transform sterols recruited from the environment for better use. Biological characteristics were compared between wild-type isolate and PcDHCR7 knock-out transformants. The results indicated that PcDHCR7 plays a key role in mycelium development and pathogenicity of zoospores in P. capsici.

Patterning the dorsal longitudinal flight muscles (DLM) of Drosophila: insights from the ablation of larval scaffolds

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3755-3763 ◽  
Author(s):  
J.J. Fernandes ◽  
H. Keshishian
Keyword(s):  
Transcription Factor ◽  
De Novo ◽  
Muscle Fibers ◽  
Myoblast Fusion ◽  
The Other ◽  
Correct Number ◽  
Larval Muscle ◽  
Actin Isoform ◽  
Flight Muscles

The six Dorsal Longitudinal flight Muscles (DLMs) of Drosophila develop from three larval muscles that persist into metamorphosis and serve as scaffolds for the formation of the adult fibers. We have examined the effect of muscle scaffold ablation on the development of DLMs during metamorphosis. Using markers that are specific to muscle and myoblasts we show that in response to the ablation, myoblasts which would normally fuse with the larval muscle, fuse with each other instead, to generate the adult fibers in the appropriate regions of the thorax. The development of these de novo DLMs is delayed and is reflected in the delayed expression of erect wing, a transcription factor thought to control differentiation events associated with myoblast fusion. The newly arising muscles express the appropriate adult-specific Actin isoform (88F), indicating that they have the correct muscle identity. However, there are frequent errors in the number of muscle fibers generated. Ablation of the larval scaffolds for the DLMs has revealed an underlying potential of the DLM myoblasts to initiate de novo myogenesis in a manner that resembles the mode of formation of the Dorso-Ventral Muscles, DVMs, which are the other group of indirect flight muscles. Therefore, it appears that the use of larval scaffolds is a superimposition on a commonly used mechanism of myogenesis in Drosophila. Our results show that the role of the persistent larval muscles in muscle patterning involves the partitioning of DLM myoblasts, and in doing so, they regulate formation of the correct number of DLM fibers.

A novel SLC2A1 mutation linking hemiplegic migraine with alternating hemiplegia of childhood

Cephalalgia ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Claudia M Weller ◽  
Wilhelmina G Leen ◽  
Brian GR Neville ◽  
John S Duncan ◽  
Boukje de Vries ◽  
...  
Keyword(s):  
De Novo ◽  
The Other ◽  
Brain Disorders ◽  
Complex Phenotype ◽  
Hemiplegic Migraine ◽  
Alternating Hemiplegia Of Childhood ◽  
Genetic Overlap ◽  
Slc2a1 Gene ◽  
Small Set

Background Hemiplegic migraine (HM) and alternating hemiplegia of childhood (AHC) are rare episodic neurological brain disorders with partial clinical and genetic overlap. Recently, ATP1A3 mutations were shown to account for the majority of AHC patients. In addition, a mutation in the SLC2A1 gene was reported in a patient with atypical AHC. We therefore investigated whether mutations in these genes may also be involved in HM. Furthermore, we studied the role of SLC2A1 mutations in a small set of AHC patients without ATP1A3 mutations. Methods We screened 42 HM patients (21 familial and 21 sporadic patients) for ATP1A3 and SLC2A1 mutations. In addition, four typical AHC patients and one atypical patient with overlapping symptoms of both disorders were screened for SLC2A1 mutations. Results A pathogenic de novo SLC2A1 mutation (p.Gly18Arg) was found in the atypical patient with overlapping symptoms of AHC and hemiplegic migraine. No mutations were found in the HM and the other AHC patients. Conclusion Screening for a mutation in the SLC2A1 gene should be considered in patients with a complex phenotype with overlapping symptoms of hemiplegic migraine and AHC.

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.

scholarly journals Construction of an Alternative NAD + De Novo Biosynthesis Pathway

2021 ◽  
pp. 2004632
Author(s):  
Yong Ding ◽  
Xinli Li ◽  
Geoff P. Horsman ◽  
Pengwei Li ◽  
Min Wang ◽  
...  
Keyword(s):  
De Novo ◽  
Biosynthesis Pathway ◽  
De Novo Biosynthesis

scholarly journals Strategies for acquiring the phospholipid metabolite inositol in pathogenic bacteria, fungi and protozoa: making it and taking it

Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1386-1396 ◽  
Author(s):  
Todd B. Reynolds
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Candida Albicans ◽  
Trypanosoma Brucei ◽  
Pathogenic Bacteria ◽  
De Novo ◽  
The Other ◽  
Inositol Monophosphatase ◽  
Essential Nutrient ◽  
Phosphate Synthase

myo-Inositol (inositol) is an essential nutrient that is used for building phosphatidylinositol and its derivatives in eukaryotes and even in some eubacteria such as the mycobacteria. As a consequence, fungal, protozoan and mycobacterial pathogens must be able to acquire inositol in order to proliferate and cause infection in their hosts. There are two primary mechanisms for acquiring inositol. One is to synthesize inositol from glucose 6-phosphate using two sequentially acting enzymes: inositol-3-phosphate synthase (Ino1p) converts glucose 6-phosphate to inositol 3-phosphate, and then inositol monophosphatase (IMPase) dephosphorylates inositol 3-phosphate to generate inositol. The other mechanism is to import inositol from the environment via inositol transporters. Inositol is readily abundant in the bloodstream of mammalian hosts, providing a source from which many pathogens could potentially import inositol. However, despite this abundance of inositol in the host, some pathogens such as the bacterium Mycobacterium tuberculosis and the protist parasite Trypanosoma brucei must be able to make inositol de novo in order to cause disease (M. tuberculosis) or even grow (T. brucei). Other pathogens such as the fungus Candida albicans are equally adept at causing disease by importing inositol or by making it de novo. The role of inositol acquisition in the biology and pathogenesis of the parasite Leishmania and the fungus Cryptococcus are being explored as well. The specific strategies used by these pathogens to acquire inositol while in the host are discussed in relation to each pathogen's unique metabolic requirements.

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