Abstract: A method for producing a microbial oil includes the steps of: genetically modifying a labyrinthulid by disrupting and/or silencing a gene, or by transforming another gene in addition to the disruption and/or gene silencing of the gene; culturing the labyrinthulid, such that a fatty acid composition accumulated in the labyrinthulid comprises an increased EPA content; and collecting the microbial oil having the increased EPA content from the labyrinthulid. The increased EPA content is not less than 3.3% of a total fatty acid composition.

Abstract: A microbial oil is obtained from Labyrinthulomycetes in which a gene for fatty acid biosynthesis has been disrupted or an expression of the gene has been inhibited to highly accumulate the fatty acid. The microbial oil typically contains: (a) 1.5% or more of arachidonic acid (AA) based on a total amount of fatty acid; (b) 0.2% or more of dihomo-?-linolenic acid (DGLA) based on the total amount of fatty acid; (c) 0.04% or more of eicosatetraenoic acid (ETA) based on the total amount of fatty acid; (d) 3.8% or more of eicosapentaenoic acid (EPA) based on the total amount of fatty acid; (e) 13.7% or less of n-6 docosapentaenoic acid (n-6DPA) based on the total amount of fatty acid; and (f) 43.9% or less of docosahexaenoic acid (DHA) based on the total amount of fatty acid.

Abstract: A microbial oil is extracted from stramenopile transformed with a gene associated with synthesis of fatty acids, the gene encoding a fatty acid desaturase. The stramenopile belongs to the class Labyrinthulomycete. The microbial oil satisfies one or more of the following requirements: (a) an amount of arachidonic acid is 7% or less based on a total amount of the fatty acid composition; (b) an amount of DPA is 9% or less based on the total amount of the fatty acid composition; (c) an amount of ETA is 0.04% or more based on the total amount of the fatty acid composition; (d) an amount of EPA is 7% or more based on the total amount of the fatty acid composition; and (e) an amount of DHA is 45% or more based on the total amount of the fatty acid composition.

Abstract: A microbial oil is obtained from Labyrinthulomycetes in which a gene for fatty acid biosynthesis has been disrupted or an expression of the gene has been inhibited to highly accumulate the fatty acid. The microbial oil typically contains: (a) 1.5% or more of arachidonic acid (AA) based on a total amount of fatty acid; (b) 0.2% or more of dihomo-?-linolenic acid (DGLA) based on the total amount of fatty acid; (c) 0.04% or more of eicosatetraenoic acid (ETA) based on the total amount of fatty acid; (d) 3.8% or more of eicosapentaenoic acid (EPA) based on the total amount of fatty acid; (e) 13.7% or less of n-6 docosapentaenoic acid (n-6DPA) based on the total amount of fatty acid; and (f) 43.9% or less of docosahexaenoic acid (DHA) based on the total amount of fatty acid.

Abstract: A microbial oil is extracted from stramenopile transformed with a gene associated with synthesis of fatty acids, the gene encoding a fatty acid desaturase. The stramenopile belongs to the class Labyrinthulomycete. The microbial oil satisfies one or more of the following requirements: (a) an amount of arachidonic acid is 7% or less based on a total amount of the fatty acid composition; (b) an amount of DPA is 9% or less based on the total amount of the fatty acid composition; (c) an amount of ETA is 0.04% or more based on the total amount of the fatty acid composition; (d) an amount of EPA is 7% or more based on the total amount of the fatty acid composition; and (e) an amount of DHA is 45% or more based on the total amount of the fatty acid composition.

Abstract: To provide a transformation method for producing a stramenopile organism having an improved unsaturated fatty acid production capability by disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner. [Solution] A method for transforming a stramenopile organism, which comprises disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner, and which is characterized in that the stramenopile organism is selected from Thraustochytrium aureum, Parietichytrium sarkarianum, Thraustochytrium roseum and Parietichytrium sp. and the gene to be disrupted or of which the expression is to be inhibited is a gene associated with the biosynthesis of a fatty acid.

Abstract: A method for transforming a stramenopile includes transferring a foreign gene into the stramenopile which is a microorganism belonging to the class Labyrinthula, more specifically, to a genus Labyrinthula, Altornia, Aplanochytrium, Schizochytrium, Aurantiochytrium, Thraustochytrium, Ulkenia, etc. The foreign gene, which is a gene relating to tolerance against an antibiotic, a colorimetric protein and/or a fatty acid desaturase (?5 desaturase gene, ?12 desaturase gene and/or ?3 desaturase gene), is transferred by using the electroporation or gene-gun technique.

Abstract: Disclosed is a transformation method whereby an ability to produce a useful substance of a stramenopile can be improved. The method for transforming a stramenopile comprises transferring a foreign gene into the stramenopile which is a microorganism belonging to the class Labyrinthula, more specifically, to a genus Labyrinthula, Altornia, Aplanochytrium, Schizochytrium, Aurantiochytrium, Thraustochytrium, Ulkenia, etc. Said foreign gene, which is a gene relating to tolerance against an antibiotic, a colorimetric protein and/or a fatty acid desaturase (?5 desaturase gene, ?12 desaturase gene and/or ?3 desaturase gene), is transferred by using the electroporation or gene-gun technique.

Abstract: To provide a transformation method for producing a stramenopile organism having an improved unsaturated fatty acid production capability by disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner. [Solution] A method for transforming a stramenopile organism, which comprises disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner, and which is characterized in that the stramenopile organism is selected from Thraustochytrium aureum, Parietichytrium sarkarianum, Thraustochytrium roseum and Parietichytrium sp. and the gene to be disrupted or of which the expression is to be inhibited is a gene associated with the biosynthesis of a fatty acid.

Abstract: To provide a transformation method for producing a stramenopile organism having an improved unsaturated fatty acid production capability by disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner. [Solution] A method for transforming a stramenopile organism, which comprises disrupting a gene of the stramenopile organism or inhibiting the expression of the gene in a genetically engineering manner, and which is characterized in that the stramenopile organism is selected from Thraustochytrium aureum, Parietichytrium sarkarianum, Thraustochytrium roseum and Parietichytrium sp. and the gene to be disrupted or of which the expression is to be inhibited is a gene associated with the biosynthesis of a fatty acid.

Abstract: Disclosed is a transformation method whereby an ability to produce a useful substance of a stramenopile can be improved. The method for transforming a stramenopile comprises transferring a foreign gene into the stramenopile which is a microorganism belonging to the class Labyrinthula, more specifically, to a genus Labyrinthula, Altornia, Aplanochytrium, Schizochytrium, Aurantiochytrium, Thraustochytrium, Ulkenia, etc. Said foreign gene, which is a gene relating to tolerance against an antibiotic, a colorimetric protein and/or a fatty acid desaturase (?5 desaturase gene, ?12 desaturase gene and/or ?3 desaturase gene), is transferred by using the electroporation or gene-gun technique.

Abstract: Disclosed is a method for determining the fatty acid synthesis pathway of a microorganism. Specifically disclosed is a method for determining the fatty acid synthesis pathway of a microorganism, which is characterized by producing degenerate primers for a fatty acid synthesis-related enzyme gene and determining the presence or absence of the fatty acid synthesis-related gene in the genome gene extracted from the microorganism using the degenerate primers. The sequences for degenerate primers for C20-elongase gene, which is a fatty acid synthesis-related enzyme gene, are ATHGARTWYTKBRTITTYGTICA (SEQ ID NO:1) and TARTRISWRTACATIADIAMRTG (SEQ ID NO:2), and the sequences for degenerate primers for ?4-desaturase gene are GGNCAYCAYCMITAYACNAA (SEQ ID NO:3) and TCDATYTGRTGIBWIARNCC (SEQ ID NO:4). The microorganism is one belonging to the class Labyrinthulea. Also specifically disclosed is a PCR primer set for use in the determination method.