Biosynthesis and regulation of microbial polyunsaturated fatty acid production.

All organisms have evolved several defence systems in order to protect themselves against bacteria, fungi and viruses Higher organisms have developed a complex network of humoral and cellular responses, called adaptive immunity A second defence system, innate immunity, was discovered in the early 1980s, consisting of small cationic peptides with a broad antimicrobial spectrum These proteins act immediately at sites of infection or inflammation The production of proteins with antimicrobial activity was not limited to higher organisms but was also found in insects, plants and microorganisms During the last 2 decades a broad range of proteins with very different structural features have been isolated and characterised from differing organisms ranging from bacteria to human beings Over 500 cationic membrane-acting proteins with antimicrobial and antifungal activities have been identified to date Apart from these proteins, a very large number of antifungal proteins active on the fungal cell wall, on enzymes of the cell wall synthesis machinery, the plasma membrane and on intracellular targets have been characterised

Antifungal proteins: targets, mechanisms and prospective applications.

The release of the genome sequences of two strains of Aspergillus niger has allowed systems-level investigations of this important microbial cell factory. To this end, tools for doing data integration of multi-ome data are necessary, and especially interesting in the context of metabolism. On the basis of an A. niger bibliome survey, we present the largest model reconstruction of a metabolic network reported for a fungal species. The reconstructed gapless metabolic network is based on the reportings of 371 articles and comprises 1190 biochemically unique reactions and 871 ORFs. Inclusion of isoenzymes increases the total number of reactions to 2240. A graphical map of the metabolic network is presented. All levels of the reconstruction process were based on manual curation. From the reconstructed metabolic network, a mathematical model was constructed and validated with data on yields, fluxes and transcription. The presented metabolic network and map are useful tools for examining systemwide data in a metabolic context. Results from the validated model show a great potential for expanding the use of A. niger as a high-yield production platform.

https://www.embopress.org/doi/pdf/10.1038/msb.2008.12

Metabolic model integration of the bibliome, genome, metabolome and reactome of Aspergillus niger.

, model integration of the bibliome, genome, metabolome and reactome of Aspergillus niger

This article presents discussion of the assessment of the exposure of children to fungi, substances derived from fungi, and the environmental conditions that may lead to exposure. The principles dr...

/pdf/review-of-methods-applicable-to-the-assessment-of-mold-4rg1ks4zod.pdf

Review of methods applicable to the assessment of mold exposure to children.

A comparative study of the mycelial lipid composition of a wild strain (V35) and one unsaturated fatty acid auxotroph (UFA2) of Aspergillus niger has been performed. The lipid composition of both strains are qualitatively the same but quantitatively different. All the strains contain the following phospholipids: cardiolipin, phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylcholine, and phosphatidylserine; and triglycerides, diglycerides, mono-glycerides, ergosterol, and sterol esters as the neutral lipids; mono- and di-galactosyl diglyceride as the major glycolipids along with small amounts of the corresponding mannose analogs. Phosphatidylethanolamine and phosphatidylcholine constitute the bulk of the phospholipids. The mutant (UFA2) contains a higher level of glycerides and lower levels of sterol (both free and esterified form), phospholipids, and glycolipids than the wild type. Aspergillus niger contains C16 to C18 saturated and unsaturated fatty acids. Small...

Lipid profiles of Aspergillus niger and its unsaturated fatty acid auxotroph, UFA2.

Conidial lipids of the wild-type (V35) Aspergillus niger and its unsaturated fatty acid auxotroph (UFA2) were compared. The wild type contained lower levels (7.6%) of phospholipids and higher level...

Lipid profiles of conidia of Aspergillus niger and a fatty acid auxotroph.

The wild-type Aspergillus niger (V35) does not require fatty acids for growth. Four unsaturated fatty acid auxotrophs designated as UFA1, UFA2, UFA3, and UFA4 have been produced from this organism by treating the conidia of the wild-type strain with a mutagen, N-methyl-N'-nitro-N-nitrosoguanidine, followed by isolation on media containing monounsaturated fatty acids and the nonionic detergent, Brij 58. Optimal growth of the mutants comparable with that of the wild type was achieved with medium supplemented with C16 or C18 unsaturated fatty acids containing at least one cis double bond at the delta 9 position. Some other fatty acids (18:1 delta 11 cis and 16:1 delta 9 trans) support growth to some extent. The mutants do not grow at all in the presence of saturated fatty acids. Fatty acid analyses of the mutant, UFA2, grown in the presence of different fatty acid supplements reveal that it may be defective in a desaturase system. Experiments with unlabeled and [1-14C]palmitoyl-CoA have shown that the microsomes of the mutant (UFA2) contain a partially defective delta 9-desaturase system.

Panchanon Chattopadhyay

Papers

Lipid profiles of Aspergillus niger and its unsaturated fatty acid auxotroph, UFA2.

Lipid profiles of conidia of Aspergillus niger and a fatty acid auxotroph.

An unsaturated fatty acid mutant of Aspergillus niger with partially defective Δ9-desaturase