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Dalmia A, Daga P, Datey A, Chakravortty D, Tumaney AW. Biochemical characterization of lipid metabolic genes of Aurantiochytrium limacinum. Int J Biol Macromol 2024; 259:129078. [PMID: 38176490 DOI: 10.1016/j.ijbiomac.2023.129078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/23/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024]
Abstract
Docosahexaenoic acid (DHA) is known to have numerous health benefits and immense dietary value. There is a pressing need to have a deeper understanding of DHA metabolism. Acyl CoA: Diacylglycerol Acyltransferase (DGAT) is an important enzyme of lipid anabolism and an essential piece of the puzzle. Aurantiochytrium limacinum, a primary producer of DHA, is a good model for studying DHA metabolism. Thus, we aimed to investigate important lipid metabolic genes from A. limacinum. We cloned four putative DGATs (DGAT2a, DGAT2b, DGAT2c, and DGAT2d) from A. limacinum and performed detailed in vivo and in vitro characterization. Functional characterization showed that not all the studied genes exhibited DGAT activity. DGAT2a and DGAT2d conferred DGAT activity whereas DGAT2b showed wax synthase (WS) activity and DGAT2c showed dual function of both WS and DGAT. Based on their identified function, DGAT2b and DGAT2c were renamed as AlWS and AlWS/DGAT respectively. DGAT2a was found to exhibit a preference for DHA as a substrate. DGAT2d was found to have robust activity and emerged as a promising candidate for genetic engineering aimed at increasing oil yield. The study enriches our knowledge of lipid biosynthetic enzymes in A. limacinum, which can be utilized to design suitable application strategies.
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Affiliation(s)
- Ayushi Dalmia
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Palak Daga
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Akshay Datey
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Ajay W Tumaney
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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Yoshimi T, Hashimoto S, Kubo Y, Takeuchi M, Morimoto D, Nakagawa S, Sawayama S. Improvement of Astaxanthin Production in Aurantiochytrium limacinum by Overexpression of the Beta-Carotene Hydroxylase Gene. Appl Biochem Biotechnol 2023; 195:1255-1267. [PMID: 36346562 DOI: 10.1007/s12010-022-04172-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
Aurantiochytrium limacinum is a heterotrophic eukaryotic microorganism that can accumulate high levels of commercial products such as astaxanthin and docosahexaenoic acid. Due to its rapid growth and relatively simple extraction method, A. limacinum is considered a promising astaxanthin resource to replace the conventional microalgal production. However, the astaxanthin biosynthetic process in A. limacinum remains incompletely understood, especially in those catalysed by β-carotene hydroxylase (CrtZ) and ketolase. In this study, we overexpressed a crtZ candidate gene to increase astaxanthin production and expand our understanding of the conversion from beta-carotene to astaxanthin. The resultant transformant AlcrtZ#10 cultivated for 5 days showed a significant increase in astaxanthin production per culture (2.8-fold) and per cell (4.5-fold) compared with that of the wild-type strain. Strikingly, longer light exposure increased astaxanthin production and decreased the beta-carotene content in the wild-type strain, suggesting that light exposure duration is important for astaxanthin production in A. limacinum. Among several predicted intermediates, furthermore, the cantaxanthin produced from β-carotene by ketolase activity were enhanced in the transformant AlcrtZ#10. Although the further investigation is needed, this result suggested that the main route of astaxanthin was via cantaxanthin. Thus, our findings will be valuable not only for its application, but also for understanding the astaxanthin biosynthetic process in A. limacinum.
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Affiliation(s)
- Toru Yoshimi
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Sakiko Hashimoto
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yuki Kubo
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Masato Takeuchi
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Daichi Morimoto
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Satoshi Nakagawa
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shigeki Sawayama
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
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Endo I, Watanabe T, Miyamoto T, Monjusho-Goda H, Ohara J, Hayashi M, Hama Y, Ishibashi Y, Okino N, Ito M. C4-monomethylsterol β-glucoside and its synthase in Aurantiochytrium limacinum mh0186. Glycobiology 2021; 31:1350-1363. [PMID: 34224567 DOI: 10.1093/glycob/cwab070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/14/2022] Open
Abstract
Thraustochytrids, unicellular marine protists, synthesize polyunsaturated fatty acids (PUFAs) and PUFA-containing phospholipids; however, little is known about their glycolipids and their associated metabolism. Here, we report two glycolipids (GL-A, B) and their synthases in Aurantiochytrium limacinum mh0186. Two glycolipids were purified from A. limacinum mh0186, and they were determined by gas chromatography, mass spectrometry and two-dimensional nuclear magnetic resonance to be 3-O-β-D-glucopyranosyl-stigmasta-5,7,22-triene (GL-A) and 3-O-β-D-glucopyranosyl-4α-methyl-stigmasta-7,22-diene (GL-B), both of which are sterol β-glucosides (β-SGs); the structure of GL-B has not been reported thus far. Seven candidate genes responsible for the synthesis of these β-SGs were extracted from the draft genome database of A. limacinum using the yeast sterol β-glucosyltransferase (SGT; EC 2.4.1.173) sequence as a query. Expression analysis using Saccharomyces cerevisiae revealed that two gene products (AlSGT-1 and 2) catalyze the transfer of glucose from UDP-glucose to sterols, generating sterylglucosides (SGs). Compared to AlSGT-1, AlSGT-2 exhibited wide specificity for sterols and used C4-monomethylsterol to synthesize GL-B. The disruption of alsgt-2 but not alsgt-1 in strain mh0186 resulted in a decrease in total SG and almost complete loss of GL-B, indicating that AlSGT-2 is responsible for the synthesis of β-SGs in A. limacinum mh0186, especially GL-B, which possesses a unique sterol structure.
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Affiliation(s)
- Ikumi Endo
- Department of Bioscience and Biotechnology
| | | | - Tomofumi Miyamoto
- Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka 812-8582, Japan
| | | | | | - Masahiro Hayashi
- Department of Marine Biology and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Yoichiro Hama
- Applied Biochemistry and Food Science Course, Faculty of Agriculture, Saga University, 1 Honjo, Saga 840-8502, Japan
| | | | | | - Makoto Ito
- Department of Bioscience and Biotechnology.,Innovative Bio-Architecture Center, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395
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Laddha H, Pawar PR, Prakash G. Bioconversion of waste acid oil to docosahexaenoic acid by integration of "ex novo'' and "de novo'' fermentation in Aurantiochytrium limacinum. Bioresour Technol 2021; 332:125062. [PMID: 33839510 DOI: 10.1016/j.biortech.2021.125062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Thraustochytrids have predominantly been grown on hydrophilic substrates i.e. by "de novo" fermentation. The fatty acid composition of thraustochytrids oil in "de novo" mode is enriched in saturated palmitic acid and polyunsaturated docosahexaenoic acid. The "ex novo" fermentation of a novel Aurantiochytrium limacinum ICTSG-17 with waste acid oil altered the fatty acid composition of produced oil. This led to increased total unsaturated fatty acids (TUFA) and concomitant decrease in the total saturated fatty acids (TSFA) resulting in higher TUFA/TSFA ratio. However, cell growth and DHA content in "ex novo" were lower than that of "de novo" fermentation. Integration of "de novo" and "ex novo" fermentation modes were devised to attain high biomass and lipids enriched in DHA. Sequential "de novo"-"ex novo" fermentation resulted in ~20 g/L biomass and ~40% DHA content and higher TUFA/TSFA ratio as compared to that of "de novo" mode.
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Affiliation(s)
- Hrishikesh Laddha
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Pratik R Pawar
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Gunjan Prakash
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India.
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Sirirak K, Powtongsook S, Suanjit S, Jaritkhuan S. Effectiveness of various bioreactors for thraustochytrid culture and production ( Aurantiochytruim limacinum BUCHAXM 122). PeerJ 2021; 9:e11405. [PMID: 34123585 PMCID: PMC8164841 DOI: 10.7717/peerj.11405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/14/2021] [Indexed: 11/20/2022] Open
Abstract
This study aimed to develop bioreactors for cultivation of thraustochytrid, Aurantiochytrium limacinum BUCHAXM 122, that are low in cost and simple to operate. Obtaining maximum biomass and fatty acid production was a prerequisite. Three bioreactor designs were used: stirred tank bioreactor (STB), bubble bioreactor (BB) and internal loop airlift bioreactor (ILAB). The bioreactors were evaluated for their influence on oxygen mass transfer coefficient (kLa), using various spargers, mixing speed, and aeration rates. Biomass and DHA production from STB, BB, ILAB were then compared with an incubator shaker, using batch culture experiments. Results showed that a bundle of eight super-fine pore air stones was the best type of aeration sparger for all three bioreactors. Optimal culture conditions in STB were 600 rpm agitation speed and 2 vvm aeration rate, while 2 vvm and 1.5 vvm aeration provided highest biomass productivity in BB and ILAB, respectively. Antifoam agent was needed for all reactor types in order to reduce excessive foaming. Results indicated that with optimized conditions, these bioreactors are capable of thraustochytrid cultivation with a similar efficiency as cultivation using a rotary shaker. STB had the highest kLa and provided the highest biomass of 43.05 ± 0.35 g/L at 48 h. BB was simple in design, had low operating costs and was easy to build, but yielded the lowest biomass (27.50 ± 1.56 g/L). ILAB, on the other hand, had lower kLa than STB, but provided highest fatty acid productivity, of 35.36 ± 2.51% TFA.
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Affiliation(s)
- Khanoksinee Sirirak
- Graduate Program in Environmental Science, Faculty of Science, Burapha University, Chon Buri, Thailand
| | - Sorawit Powtongsook
- Center of Excellence for Marine Biotechnology, Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Sudarat Suanjit
- Department of Microbiology, Faculty of Science, Burapha University, Chon Buri, Thailand
| | - Somtawin Jaritkhuan
- Department of Aquatic Science, Faculty of Science, Burapha University, Chon Buri, Thailand
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Pawar PR, Lali AM, Prakash G. Integration of continuous-high cell density-fed-batch fermentation for Aurantiochytrium limacinum for simultaneous high biomass, lipids and docosahexaenoic acid production. Bioresour Technol 2021; 325:124636. [PMID: 33513448 DOI: 10.1016/j.biortech.2020.124636] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/25/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Docosahexaenoic acid (DHA) rich oil or biomass is currently being produced by fermentation of thraustochytrids by repeated fed-batch. Continuous cultivation has not been successful for DHA production because of excess carbon and limited nitrogen conditions requirement. The present study describes an alternative integrative fermentation strategy to simultaneously produce high cell density, lipids and DHA in continuous mode for Aurantiochytrium limacinum. The high cell density system (≥120 g/L DCW basis) on carbon feeding led to DHA productivity of 0.508 g/L.h on poultry waste based medium with a process time of 48-54 h. The strategy integrates the advantages of repeated fed-batch for high cell densities and DHA content in continuous cultivation.
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Affiliation(s)
- Pratik R Pawar
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, India
| | - Arvind M Lali
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai, Maharashtra, India
| | - Gunjan Prakash
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, India.
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Pawar PR, Velani S, Kumari S, Lali AM, Prakash G. Isolation and optimization of a novel thraustochytrid strain for DHA rich and astaxanthin comprising biomass as aquafeed supplement. 3 Biotech 2021; 11:71. [PMID: 33489688 DOI: 10.1007/s13205-020-02616-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 12/26/2020] [Indexed: 01/30/2023] Open
Abstract
A marine organism, belonging to the Thraustochytrids family was isolated from mangroves of Mumbai, India. The isolated strain was identified as Aurantiochytrium limacinum by internal transcribed spacer sequence analysis. Optimization of process parameters yielded 14.47 g/L dry cell weight containing 55-58% oil in 3.5 days' cultivation on glucose, yeast extract, and peptone in the bioreactor. Docosahexaenoic acid (DHA) was found to be the dominant long-chain polyunsaturated fatty acid, accounting for 32-35% of total fatty acid content. The process parameter was tweaked to simultaneously synthesize astaxanthin along with DHA. The concurrent synthesis of DHA and astaxanthin-containing biomass establishes the isolated strain as a perfect choice for aquafeed. Accession number: NCBI accession number MN046792.
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Affiliation(s)
- Pratik R Pawar
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Sneha Velani
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Sujata Kumari
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Arvind M Lali
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai, India
| | - Gunjan Prakash
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
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Kubo Y, Shiroi M, Higashine T, Mori Y, Morimoto D, Nakagawa S, Sawayama S. Enhanced Production of Astaxanthin without Decrease of DHA Content in Aurantiochytrium limacinum by Overexpressing Multifunctional Carotenoid Synthase Gene. Appl Biochem Biotechnol 2020; 193:52-64. [PMID: 32808245 DOI: 10.1007/s12010-020-03403-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/12/2020] [Indexed: 01/01/2023]
Abstract
Aurantiochytrium limacinum produces both docosahexaenoic acid (DHA) and astaxanthin, respectively. Organisms that produce these industrially important materials more efficiently than microalgae are currently needed. In this study, we overexpressed a putative homolog of CarS, which is involved in synthesizing the astaxanthin precursor, β-carotene, in A. limacinum to increase carotenoid synthesis with the goal of obtaining strains that produce large amounts of both DHA and carotenoids. AlCarS transformants #1 and #18 produced significantly increased amounts of astaxanthin as assessed according to culture (up to 5.8-fold) and optical density (up to 9.3-fold). The improved astaxanthin production of these strains did not affect their DHA productivity. Additionally, their CarS expression levels were higher than those of the wild-type strain, suggesting that CarS overexpression enhanced β-carotene production, which in turn improved astaxanthin productivity. Although cell yields were slightly decreased, these features will be valuable in health food, medical care, and animal feed fields.
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Affiliation(s)
- Yuki Kubo
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Mai Shiroi
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Tokuhiro Higashine
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yuki Mori
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Daichi Morimoto
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Satoshi Nakagawa
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shigeki Sawayama
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
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Koutsoumanis K, Allende A, Alvarez‐Ordóñez A, Bolton D, Bover‐Cid S, Chemaly M, Davies R, De Cesare A, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Cocconcelli PS, Fernández Escámez PS, Maradona MP, Querol A, Suarez JE, Sundh I, Vlak J, Barizzone F, Correia S, Herman L. Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 11: suitability of taxonomic units notified to EFSA until September 2019. EFSA J 2020; 18:e05965. [PMID: 32874211 PMCID: PMC7448003 DOI: 10.2903/j.efsa.2020.5965] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Qualified presumption of safety (QPS) was developed to provide a generic safety evaluation for biological agents to support EFSA's Scientific Panels. The taxonomic identity, body of knowledge, safety concerns and antimicrobial resistance are assessed. Safety concerns identified for a taxonomic unit (TU) are where possible to be confirmed at strain or product level, reflected by 'qualifications'. No new information was found that would change the previously recommended QPS TUs and their qualifications. The list of microorganisms notified to EFSA was updated with 54 biological agents, received between April and September 2019; 23 already had QPS status, 14 were excluded from the QPS exercise (7 filamentous fungi, 6 Escherichia coli, Sphingomonas paucimobilis which was already evaluated). Seventeen, corresponding to 16 TUs, were evaluated for possible QPS status, fourteen of these for the first time, and Protaminobacter rubrum, evaluated previously, was excluded because it is not a valid species. Eight TUs are recommended for QPS status. Lactobacillus parafarraginis and Zygosaccharomyces rouxii are recommended to be included in the QPS list. Parageobacillus thermoglucosidasius and Paenibacillus illinoisensis can be recommended for the QPS list with the qualification 'for production purposes only' and absence of toxigenic potential. Bacillus velezensis can be recommended for the QPS list with the qualification 'absence of toxigenic potential and the absence of aminoglycoside production ability'. Cupriavidus necator, Aurantiochytrium limacinum and Tetraselmis chuii can be recommended for the QPS list with the qualification 'production purposes only'. Pantoea ananatis is not recommended for the QPS list due to lack of body of knowledge in relation to its pathogenicity potential for plants. Corynebacterium stationis, Hamamotoa singularis, Rhodococcus aetherivorans and Rhodococcus ruber cannot be recommended for the QPS list due to lack of body of knowledge. Kodamaea ohmeri cannot be recommended for the QPS list due to safety concerns.
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Keegan JD, Currie D, Knox A, Moran CA. Heterotrophic Aurantiochytrium sp. supplementation to layer diets sustainably increases the omega-3 concentration of eggs. Br Poult Sci 2019; 60:570-578. [PMID: 31124696 DOI: 10.1080/00071668.2019.1622079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
1. The consumption of adequate amounts of the long-chain polyunsaturated omega-3 fatty acids (n-3 LC-PUFA) has been associated with beneficial effects on human health. Eggs are commonly consumed worldwide, and their omega-3 content can be easily altered by changing the diets of laying hens and so represent an important target for enrichment. 2. In this study, the effect of supplementing laying hens with DHA-rich, Aurantiochytrium limacinum at three different inclusion levels was investigated over a 24-week period. 3. Significant increases in egg DHA concentrations were observed after four weeks and were maintained for the duration of the 24-week study. The supplemented eggs in the current study had a DHA content of 82, 101, and 129 mg/yolk when supplemented with 0.25%, 0.5% and 1% treatments, respectively, which meets the EU criteria to be considered 'high in omega-3'. 4. Using the sustainably grown protist Aurantiochytrium limacinum to supplement layer diets increased the egg DHA concentration and decreased the n-6/n-3 ratio, improving the nutritional value of the eggs for human consumers.
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Affiliation(s)
- J D Keegan
- Regulatory Affairs Department, Alltech European Bioscience Centre , Dunboyne , Ireland
| | - D Currie
- Roslin Nutrition Ltd ., Aberlady , Scotland
| | - A Knox
- Roslin Nutrition Ltd ., Aberlady , Scotland
| | - C A Moran
- Regulatory Affairs Department, Alltech SARL , Vire , France
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Okino N, Wakisaka H, Ishibashi Y, Ito M. Visualization of Endoplasmic Reticulum and Mitochondria in Aurantiochytrium limacinum by the Expression of EGFP with Cell Organelle-Specific Targeting/Retaining Signals. Mar Biotechnol (NY) 2018; 20:182-192. [PMID: 29380081 DOI: 10.1007/s10126-018-9795-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 01/11/2018] [Indexed: 06/07/2023]
Abstract
Thraustochytrids are single cell marine eukaryotes that produce large amounts of polyunsaturated fatty acids such as docosahexaenoic acid. In the present study, we report the visualization of endoplasmic reticulum (ER) and mitochondria in a type strain of the thraustochytrid, Aurantiochytrium limacinum ATCC MYA-1381, using the enhanced green fluorescent protein (EGFP) with specific targeting/retaining signals. We expressed the egfp gene with ER targeting/retaining signals from A. limacinum calreticulin or BiP/GRP78 in the thraustochytrid, resulting in the distribution of EGFP signals at the perinuclear region and near lipid droplets. ER-Tracker™ Red, an authentic fluorescent probe for the visualization of ER in mammalian cells, also stained the same region. We observed small lipid droplets generated from the visualized ER in the early growth phase of cell culture. Expression of the egfp gene with the mitochondria targeting signal from A. limacinum cytochrome c oxidase resulted in the localization of EGFP near the plasma membrane. The distribution of EGFP signals coincided with that of MitoTracker® Red CMXRos, which is used to visualize mitochondria in eukaryotes. The ER and mitochondria of A. limacinum were visualized for the first time by EGFP with thraustochytrid cell organelle-specific targeting/retaining signals. These results will contribute to classification of the intracellular localization of proteins expressed in ER and mitochondria as well as analyses of these cell organelles in thraustochytrids.
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Affiliation(s)
- Nozomu Okino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
| | - Hiroyoshi Wakisaka
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
| | - Yohei Ishibashi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
| | - Makoto Ito
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
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12
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Sun H, Chen H, Zang X, Hou P, Zhou B, Liu Y, Wu F, Cao X, Zhang X. Application of the Cre/loxP Site-Specific Recombination System for Gene Transformation in Aurantiochytrium limacinum. Molecules 2015; 20:10110-21. [PMID: 26039334 PMCID: PMC6272215 DOI: 10.3390/molecules200610110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/08/2015] [Accepted: 05/21/2015] [Indexed: 12/14/2022] Open
Abstract
The Cre/loxP site-specific recombination system was applied to Aurantiochytrium limacinum to obtain a transformant without the antibiotic resistance marker gene. First, the enhanced green fluorescent protein gene (egfp) and chloramphenicol resistance gene (Cmr), along with the two loxP loci, were integrated into the genome of A. limacinum OUC88 using 18S rDNA sequences as the homologous recombination sites. Then plasmid pSH65, containing a zeocin resistance gene (Bler) was transferred into A. limacinum OUC_CG. After induction with galactose, repeated passage in culture and PCR-based assessment, the pSH65 plasmid was lost and A. limacinum OUC_EG host was shown to no longer have resistance to 100 mg chloramphenicol/L or 5 mg zeocin/L. Through southern blotting and fluorescence detection, egfp was found to be integrated into the genome of A. limacinum OUC_EG, and EGFP was successfully expressed in the cells. The successful application of the Cre/loxP system demonstrates an experimental basis for genetic modification of A. limacinum so as to obtain transformed strains with no antibiotic resistance marker genes.
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Affiliation(s)
- Hengyi Sun
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Hao Chen
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Xiaonan Zang
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Pan Hou
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Bingbing Zhou
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Yuantao Liu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Fei Wu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Xiaofei Cao
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
| | - Xuecheng Zhang
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China.
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