scholarly journals Proteome analysis of xylose metabolism inRhodotorula toruloidesduring lipid production

2019 ◽  
Author(s):  
Ievgeniia A. Tiukova ◽  
Jule Brandenburg ◽  
Johanna Blomqvist ◽  
Sabine Samples ◽  
Nils Mikkelsen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Growth Phase ◽  
Exponential Growth ◽  
Lipid Production ◽  
Proteome Analysis ◽  
Exponential Growth Phase ◽  
Sugar Uptake ◽  
Beta Oxidation

AbstractBackgroundRhodotorula toruloidesis a promising platform organism for production of lipids from lignocellulosic substrates. Little is known about the metabolic aspects of lipid production from the lignocellolosic sugar xylose by oleaginous yeasts in general andR. toruloidesin particular. This study presents the first proteome analysis of the metabolism ofR. toruloidesduring conversion of xylose to lipids.ResultsR. toruloidescultivated on either glucose or xylose was subjected to comparative analysis of its growth dynamics, lipid composition, fatty acid profiles and proteome. The maximum growth and sugar uptake rate of glucose-grownR. toruloidescells were almost twice that of xylose-grown cells. Cultivation on xylose medium resulted in a lower final biomass yield although final cellular lipid content was similar between glucose- and xylose-grown cells. Analysis of lipid classes revealed the presence of monoacylglycerol in the early exponential growth phase as well as a high proportion of free fatty acids. Carbon source-specific changes in lipid profiles were only observed at early exponential growth phase, where C18 fatty acids were more saturated in xylose-grown cells. Proteins involved in sugar transport, initial steps of xylose assimilation and NADPH regeneration were among the proteins whose levels increased the most in xylose-grown cells across all time points. The levels of enzymes involved in the mevalonate pathway, phospholipid biosynthesis and amino acids biosynthesis differed in response to carbon source. In addition, xylose-grown cells contained higher levels of enzymes involved in peroxisomal beta-oxidation and oxidative stress response compared to cells cultivated on glucose.ConclusionsThe results obtained in the present study suggest that sugar import is the limiting step during xylose conversion byR. toruloidesinto lipids. NADPH appeared to be regenerated primarily through pentose phosphate pathway although it may also involve malic enzyme as well as alcohol and aldehyde dehydrogenases. Increases in enzyme levels of both fatty acid biosynthesis and beta-oxidation in xylose-grown cells was predicted to result in a futile cycle. The results presented here are valuable for the development of lipid production processes employingR. toruloideson xylose-containing substrates.

scholarly journals Saccharomyces cerevisiae contains four fatty acid activation (FAA) genes: an assessment of their role in regulating protein N-myristoylation and cellular lipid metabolism.

1994 ◽  
Vol 127 (3) ◽  
pp. 751-762 ◽  
Author(s):  
D R Johnson ◽  
L J Knoll ◽  
D E Levin ◽  
J I Gordon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Vegetative Growth ◽  
Fatty Acid Synthetase ◽  
Acid Activation ◽  
Beta Oxidation ◽  
Fatty Acid Activation ◽  
Long Chain

Saccharomyces cerevisiae has been used as a model for studying the regulation of protein N-myristoylation. MyristoylCoA:protein N-myristoyl-transferase (Nmt1p), is essential for vegetative growth and uses myristoylCoA as its substrate. MyristoylCoA is produced by the fatty acid synthetase (Fas) complex and by cellular acylCoA synthetases. We have recently isolated three unlinked Fatty Acid Activation (FAA) genes encoding long chain acylCoA synthetases and have now recovered a fourth by genetic complementation. When Fas is active and NMT1 cells are grown on media containing a fermentable carbon source, none of the FAA genes is required for vegetative growth. When Fas is inactivated by a specific inhibitor (cerulenin), NMT1 cells are not viable unless the media is supplemented with long chain fatty acids. Supplementation of cellular myristoylCoA pools through activation of imported myristate (C14:0) is predominantly a function of Faa1p, although Faa4p contributes to this process. Cells with nmt181p need larger pools of myristoylCoA because of the mutant enzyme's reduced affinity for this substrate. Faa1p and Faa4p are required for maintaining the viability of nmt1-181 strains even when Fas is active. Overexpression of Faa2p can rescue nmt1-181 cells due to activation of an endogenous pool of C14:0. This pool appears to be derived in part from membrane phospholipids since overexpression of Plb1p, a nonessential lysophospholipase/phospholipase B, suppresses the temperature-sensitive growth arrest and C14:0 auxotrophy produced by nmt1-181. None of the four known FAAs is exclusively responsible for targeting imported fatty acids to peroxisomal beta-oxidation pathways. Introduction of a peroxisomal assembly mutation, pas1 delta, into isogenic NMT1 and nmt1-181 strains with wild type FAA alleles revealed that when Fas is inhibited, peroxisomes contribute to myristoylCoA pools used by Nmt1p. When Fas is active, a fraction of cellular myristoylCoA is targeted to peroxisomes. A NMT1 strain with deletions of all four FAAs is still viable at 30 degrees C on media containing myristate, palmitate, or oleate as the sole carbon source--indicating that S. cerevisiae contains at least one other FAA which directs fatty acids to beta-oxidation pathways.

scholarly journals Lipid and Fatty Acids Accumulation Features of Entomoneis cf. paludosa during Exponential and Stationary Growth Phases in Laboratory Culture

Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 459
Author(s):  
Yekaterina Bedoshvili ◽  
Yulia Podunay ◽  
Alyona Nikonova ◽  
Artyom Marchenkov ◽  
Elvira Bairamova ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Stationary Phase ◽  
Growth Phase ◽  
Exponential Growth ◽  
Lipid Bodies ◽  
Growth Phases ◽  
Stationary Growth ◽  
Culture Growth

Diatoms are capable of accumulating substantial amounts of triacylglycerides in their cells, which differ in the composition of fatty acids depending on the conditions of cultivation, making them attractive subjects in biotechnology. In the present study, we characterized the structural features of lipid bodies in the diatom Entomoneis cf. paludosa (W. Smith) Reimer strain 8.0727-B and revealed the peculiarities of fatty acid composition in cultures during the stationary and exponential growth phases. Laser scanning confocal microscopy revealed an increased number of lipid bodies in the cytoplasm during the stationary phase of culture growth. Electron microscopy of ultrathin sections showed that an extreme increase in the number and size of plastoglobules in the cells occurs in the stationary phase of culture growth. The gas chromatography with mass spectrometric detection method revealed differences in the fatty acid composition depending on the growth phase. The studied strain can be recommended as a source of hexadecanoic and octadecanoic fatty acids from the culture during the stationary growth phase, as well as eicosapentaenoic fatty acid from the culture during the exponential growth phase.

A particulate chitin synthase from Aspergillus flavus Link: the properties, location, and levels of activity in mycelium and regenerating protoplast preparations

1976 ◽  
Vol 22 (7) ◽  
pp. 915-921 ◽  
Author(s):  
P. M. Moore ◽  
J. F. Peberdy
Keyword(s):  
Protein Synthesis ◽  
Carbon Source ◽  
Aspergillus Flavus ◽  
Growth Phase ◽  
Exponential Growth ◽  
Incubation Temperature ◽  
Specific Activity ◽  
Chitin Synthase ◽  
Exponential Growth Phase ◽  
Net Protein

Chitin synthase (EC 2.4.1.16) has been characterized in Aspergillus flavus. A Km value of 2.5 mM was obtained for the substrate UDPGlcNAc. The enzyme had a requirement for GlcNAc, and Mg2+ and activity was increased in the presence of soluble chitodextrins F1 and F2. The optimum activity was obtained using Tris–HCl buffer, pH 7.5, with a secondary peak at pH 6.2 and an incubation temperature of 29.5 °C.Distribution patterns of chitin synthase in protoplasts and mycelial material were very similar. The highest specific activity was found in a 200 000 × g fraction.Enzyme levels in growing mycelium increased during the exponential growth phase after which they declined. Activity also increased during the early stages of regeneration of both conidial and mycelial protoplasts, despite an initial lack in net protein synthesis. Chitin synthase levels were also dependent upon the carbon source available during regeneration.

scholarly journals Bicarbonate for microalgae cultivation: a case study in a chlorophyte, Tetradesmus wisconsinensis isolated from a Norwegian lake

2021 ◽  
Author(s):  
Ikumi Umetani ◽  
Eshetu Janka ◽  
Michal Sposób ◽  
Chris J. Hulatt ◽  
Synne Kleiven ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Production ◽  
Cetane Number ◽  
Fluorescence Analysis ◽  
Dry Weight ◽  
Maximum Growth ◽  
Biodiesel Fuel ◽  
Fatty Acid Production ◽  
Total Fatty Acids

AbstractBicarbonate was evaluated as an alternative carbon source for a green microalga, Tetradesmus wisconsinensis, isolated from Lake Norsjø in Norway. Photosynthesis, growth, and lipid production were studied using four inorganic carbon regimes: (1) aeration only, (2) 20 mM NaHCO3, (3) 5% (v/v) CO2 gas, and (4) combination of 20 mM NaHCO3 and 5% CO2. Variable chlorophyll a fluorescence analysis revealed that the bicarbonate treatment supported effective photosynthesis, while the CO2 treatment led to inefficient photosynthetic activity with a PSII maximum quantum yield as low as 0.31. Conversely, bicarbonate and CO2 treatments gave similar biomass and fatty acid production. The maximum growth rate, the final cell dry weight, and total fatty acids under the bicarbonate-only treatment were 0.33 (± 0.06) day−1, 673 (± 124) mg L−1 and 75 (± 5) mg g−1 dry biomass, respectively. The most abundant fatty acid components were α-linolenic acid and polyunsaturated fatty acids constituting 69% of the total fatty acids. The fatty acid profile eventuated in unsuitable biodiesel fuel properties such as high degree of unsaturation and low cetane number; however, it would be relevant for food and feed applications. We concluded that bicarbonate could give healthy growth and comparative product yields as CO2.

The ability of ectomycorrhizal fungi to utilize fatty acids and a lipid as a carbon source for mycelial growth

2003 ◽  
Vol 81 (12) ◽  
pp. 1285-1292 ◽  
Author(s):  
Takefumi Hattori ◽  
Akira Ohta ◽  
Masayuki Itaya ◽  
Mikio Shimada
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Ectomycorrhizal Fungi ◽  
Mycelial Growth ◽  
The Other ◽  
Other Hand ◽  
The Family ◽  
Ecm Fungi ◽  
Relative Utilization

We have investigated growth of ectomycorrhizal (ECM) fungi (i.e., 55 strains of 32 species in 15 genera) on saturated (palmitate), monounsaturated (oleate), diunsaturated (linoleate), triunsaturated (linolenate) fatty acids, and the triacylglyceride of oleate (triolein) lipid to elucidate an ability to utilize the fatty acids and lipid as a carbon source for growth. Relative utilization ratios (URs, %) based on mycelial growth on glucose suggest that ECM fungi belonging to the family Thelephoraceae have an ability to utilize palmitate. On the other hand, ECM fungi in the genus Laccaria can utilize at least either palmitate or oleate. Furthermore, Hygropharus russula grows on palmitate, oleate, and slightly on triolein. Lactarius chrysorrheus grows only on palmitate. These fatty-acid- and lipid-utilizing fungi may be promising as model fungi for further elucidation of the metabolic ability to utilize the fatty acids and lipid as a carbon source. On the contrary, the fungi in the genus Suillus were shown to scarcely utilize the fatty acids and lipid. Furthermore, most ECM fungi did not grow on either linoleate or linolenate.Key words: carbon source, ectomycorrhizal fungi, fatty acid, lipid, mycelial growth.

Activation of the expression of the microcin C51 operon upon glucose starvation of cells at the exponential growth phase

2005 ◽  
Vol 41 (1) ◽  
pp. 40-43
Author(s):  
A. M. Veselovskii ◽  
A. Z. Metlitskaya ◽  
V. A. Lipasova ◽  
I. A. Bass ◽  
I. A. Khmel
Keyword(s):  
Growth Phase ◽  
Exponential Growth ◽  
Exponential Growth Phase ◽  
Glucose Starvation

scholarly journals Differences in power-law growth over time and indicators of COVID-19 pandemic progression worldwide

2020 ◽  
Author(s):  
Jack Merrin
Keyword(s):  
Error Analysis ◽  
Real Time ◽  
Power Law ◽  
Growth Phase ◽  
Exponential Growth ◽  
Spreading Rate ◽  
Exponential Growth Phase ◽  
Power Law Exponent ◽  
Disease Spreading ◽  
Over Time

1AbstractAn automated statistical and error analysis of 45 countries or regions with more than 1000 cases of COVID-19 as of March 28, 2020, has been performed. This study reveals differences in the rate of disease spreading rate over time in different countries. This survey observes that most countries undergo a beginning exponential growth phase, which transitions into a power-law phase, as recently suggested by Ziff and Ziff. Tracking indicators of growth, such as the power-law exponent, are a good indication of the relative danger different countries are in and show when social measures are effective towards slowing the spread. The data compiled here are usefully synthesizing a global picture, identifying country to country variation in spreading, and identifying countries most at risk. This analysis may factor into how best to track the effectiveness of social distancing policies and quarantines in real-time as data is updated each day.

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