A Two-Stage Adaptive Laboratory Evolution Strategy to Enhance Docosahexaenoic Acid Synthesis in Oleaginous Thraustochytrid

Thraustochytrid is a promising algal oil resource with the potential to meet the demand for docosahexaenoic acid (DHA). However, oils with high DHA content produced by genetic modified thraustochytrids are not accepted by the food and pharmaceutical industries in many countries. Therefore, in order to obtain non-transgenic strains with high DHA content, a two-stage adaptive laboratory evolution (ALE) strategy was applied to the thraustochytrid Aurantiochytrium sp. Heavy-ion irradiation technique was first used before the ALE to increase the genetic diversity of strains, and then two-step ALE: low temperature based ALE and ACCase inhibitor quizalofop-p-ethyl based ALE were employed in enhancing the DHA production. Using this strategy, the end-point strain E-81 with a DHA content 51% higher than that of the parental strain was obtained. The performance of E-81 strain was further analyzed by component analysis and quantitative real-time PCR. The results showed that the enhanced in lipid content was due to the up-regulated expression of key enzymes in lipid accumulation, while the increase in DHA content was due to the increased transcriptional levels of polyunsaturated fatty acid synthase. This study demonstrated a non-genetic approach to enhance lipid and DHA content in non-model industrial oleaginous strains.

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The effect of dietary docosahexaenoic acid on the expression of lipogenic genes in broilers

Australian Journal of Agricultural Research ◽

10.1071/ar05399 ◽

2007 ◽

Vol 58 (2) ◽

pp. 153 ◽

Cited By ~ 1

Author(s):

H. J. Chin ◽

Y. H. Ko ◽

T. F. Shen ◽

S. T. Ding

Keyword(s):

Fatty Acid ◽

Docosahexaenoic Acid ◽

Fatty Acid Synthase ◽

De Novo ◽

Regulatory Element ◽

Acid Synthesis ◽

Daily Weight Gain ◽

Feed Conversion ◽

Lipogenic Genes ◽

Triacylglycerol Synthesis

The objectives of this work were to determine the effects of dietary fungal docosahexaenoic acid (DHA) on tissue DHA concentration and lipogenic gene expression in broilers. A fungal (SR-21) meal product containing 31.5% total fat and 32.7% DHA (% of total fatty acids) was fed to chicken broilers at 0, 1, or 3% for 3 weeks. A diet with 1% DHA oil (containing 40% DHA) was also fed to chicken broilers as a positive control. Dietary fungal meal supplementation (3%) improved daily weight gain, food intake, and feed conversion ratio. The fungal meal supplementation increased dietary DHA content and consequently increased the DHA content in plasma, breast muscle (Pectoralis major), and livers in the broilers. The plasma triacylglycerol concentration was decreased by the supplementation of dietary DHA. The data indicate that the dietary DHA treatment modified certain aspects of the lipid metabolism, especially pathways related to triacylglycerol synthesis. Indeed, both the 1% DHA oil and 3% fungal meal treatments decreased the hepatic lipogenic transcription factor sterol regulatory element binding protein 1 (SREBP1) mRNA relative abundance, suggesting that dietary DHA supplementation decreases SREBP1 gene functions. The relative mRNA abundance of the de novo fatty acid synthesis genes, fatty acid synthase and acetyl coenzyme A carboxylase, was reduced by 1% DHA oil and 3% fungal meal treatments, suggesting that dietary DHA supplementation decreases lipogenesis in the livers of the broilers. Taken together, the fungal meal is a suitable dietary supplement to increase tissue DHA content and reduce the expression of hepatic lipogenic genes in broilers.

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An auto-inducible Escherichia coli strain obtained by adaptive laboratory evolution for fatty acid synthesis from ionic liquid-treated bamboo hydrolysate

Bioresource Technology ◽

10.1016/j.biortech.2016.09.024 ◽

2016 ◽

Vol 221 ◽

pp. 375-384 ◽

Cited By ~ 10

Author(s):

Dandan Qin ◽

Yuanliang Hu ◽

Jie Cheng ◽

Nan Wang ◽

Sha Li ◽

...

Keyword(s):

Escherichia Coli ◽

Ionic Liquid ◽

Fatty Acid ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

Coli Strain ◽

Adaptive Laboratory Evolution ◽

Laboratory Evolution

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Exergy analysis for docosahexaenoic acid production by fermentation and strain improvement by adaptive laboratory evolution for Schizochytrium sp.

Bioresource Technology ◽

10.1016/j.biortech.2019.122562 ◽

2020 ◽

Vol 298 ◽

pp. 122562 ◽

Cited By ~ 1

Author(s):

Lujing Ren ◽

Xiaoman Sun ◽

Lihui Zhang ◽

He Huang ◽

Quanyu Zhao

Keyword(s):

Docosahexaenoic Acid ◽

Acid Production ◽

Exergy Analysis ◽

Strain Improvement ◽

Adaptive Laboratory Evolution ◽

Laboratory Evolution

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Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155232 ◽

1989 ◽

Vol 47 ◽

pp. 652-653

Author(s):

Charles W. Allen ◽

Robert C. Birtcher

Keyword(s):

Elevated Temperatures ◽

Ion Irradiation ◽

Ion Beam ◽

National Laboratory ◽

Argonne National Laboratory ◽

Heavy Ion ◽

High Energy ◽

Mechanical Twinning ◽

In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

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