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Heterologous expression of Gaeumannomyces graminis lipoxygenase in Aspergillus nidulans.

Heshof R, van Schayck JP, Tamayo-Ramos JA, de Graaff LH - AMB Express (2014)

Bottom Line: The presence of the recombinant LOX induced phenotypic changes in A. nidulans transformants.We observed that the presence of LOX induced the specific production of aminopeptidase Y that possibly degrades the G. graminis lipoxygenase intercellularly.Also the presence of the protein thioredoxin reductase suggests that the G. graminis lipoxygenase is actively repressed in A. nidulans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Systems and Synthetic Biology, Microbial Systems and Synthetic Biology, Dreijenplein 10, Wageningen 6703 HB, Netherlands.

ABSTRACT
Aspergillus sp. contain ppo genes coding for Ppo enzymes that produce oxylipins from polyunsaturated fatty acids. These oxylipins function as signal molecules in sporulation and influence the asexual to sexual ratio of Aspergillus sp. Fungi like Aspergillus nidulans and Aspergillus niger contain just ppo genes where the human pathogenic Aspergillus flavus and Aspergillus fumigatus contain ppo genes as well as lipoxygenases. Lipoxygenases catalyze the synthesis of oxylipins and are hypothesized to be involved in quorum-sensing abilities and invading plant tissue. In this study we used A. nidulans WG505 as an expression host to heterologously express Gaeumannomyces graminis lipoxygenase. The presence of the recombinant LOX induced phenotypic changes in A. nidulans transformants. Also, a proteomic analysis of an A. nidulans LOX producing strain indicated that the heterologous protein was degraded before its glycosylation in the secretory pathway. We observed that the presence of LOX induced the specific production of aminopeptidase Y that possibly degrades the G. graminis lipoxygenase intercellularly. Also the presence of the protein thioredoxin reductase suggests that the G. graminis lipoxygenase is actively repressed in A. nidulans.

No MeSH data available.


Related in: MedlinePlus

A. nidulanswild type and transformant on plates and liquid media after 48 h of growth. All cultures were induced with 50 mM D-xylose. Phenotypic changes are found, the transformant expressing G. graminis LOX becomes brown while the wild type does not.
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Figure 2: A. nidulanswild type and transformant on plates and liquid media after 48 h of growth. All cultures were induced with 50 mM D-xylose. Phenotypic changes are found, the transformant expressing G. graminis LOX becomes brown while the wild type does not.

Mentions: After 48 h of growth in liquid cultures and on agar plates A. nidulans GG-LOX showed a different phenotype from the one of the wild type. As shown in Figure 2, the mycelium of A. nidulans GG-LOX showed a browner colour when compared to A. nidulans WG505. Also, the pellet size of the transformant was smaller than the one of the wild type strain. The amount of spores formed was also increased in the LOX expressing strain compared to the wild type, both in liquid culture and in agar plates, which could be caused by the produced oxylipins of the G. graminis LOX (data not shown).


Heterologous expression of Gaeumannomyces graminis lipoxygenase in Aspergillus nidulans.

Heshof R, van Schayck JP, Tamayo-Ramos JA, de Graaff LH - AMB Express (2014)

A. nidulanswild type and transformant on plates and liquid media after 48 h of growth. All cultures were induced with 50 mM D-xylose. Phenotypic changes are found, the transformant expressing G. graminis LOX becomes brown while the wild type does not.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230170&req=5

Figure 2: A. nidulanswild type and transformant on plates and liquid media after 48 h of growth. All cultures were induced with 50 mM D-xylose. Phenotypic changes are found, the transformant expressing G. graminis LOX becomes brown while the wild type does not.
Mentions: After 48 h of growth in liquid cultures and on agar plates A. nidulans GG-LOX showed a different phenotype from the one of the wild type. As shown in Figure 2, the mycelium of A. nidulans GG-LOX showed a browner colour when compared to A. nidulans WG505. Also, the pellet size of the transformant was smaller than the one of the wild type strain. The amount of spores formed was also increased in the LOX expressing strain compared to the wild type, both in liquid culture and in agar plates, which could be caused by the produced oxylipins of the G. graminis LOX (data not shown).

Bottom Line: The presence of the recombinant LOX induced phenotypic changes in A. nidulans transformants.We observed that the presence of LOX induced the specific production of aminopeptidase Y that possibly degrades the G. graminis lipoxygenase intercellularly.Also the presence of the protein thioredoxin reductase suggests that the G. graminis lipoxygenase is actively repressed in A. nidulans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Systems and Synthetic Biology, Microbial Systems and Synthetic Biology, Dreijenplein 10, Wageningen 6703 HB, Netherlands.

ABSTRACT
Aspergillus sp. contain ppo genes coding for Ppo enzymes that produce oxylipins from polyunsaturated fatty acids. These oxylipins function as signal molecules in sporulation and influence the asexual to sexual ratio of Aspergillus sp. Fungi like Aspergillus nidulans and Aspergillus niger contain just ppo genes where the human pathogenic Aspergillus flavus and Aspergillus fumigatus contain ppo genes as well as lipoxygenases. Lipoxygenases catalyze the synthesis of oxylipins and are hypothesized to be involved in quorum-sensing abilities and invading plant tissue. In this study we used A. nidulans WG505 as an expression host to heterologously express Gaeumannomyces graminis lipoxygenase. The presence of the recombinant LOX induced phenotypic changes in A. nidulans transformants. Also, a proteomic analysis of an A. nidulans LOX producing strain indicated that the heterologous protein was degraded before its glycosylation in the secretory pathway. We observed that the presence of LOX induced the specific production of aminopeptidase Y that possibly degrades the G. graminis lipoxygenase intercellularly. Also the presence of the protein thioredoxin reductase suggests that the G. graminis lipoxygenase is actively repressed in A. nidulans.

No MeSH data available.


Related in: MedlinePlus