Toxicological studies on a novel phytase expressed from synthetic genes in Aspergillus oryzae

Phytases are widely used as feed additives for monogastric animals, which cannot easily utilise the phosphorus bound in phytate (myo-inositol hexakisphosphate). The current study presents a safety evaluation of a 6-phytase produced by an Aspergillus oryzae strain expressing two synthetic genes, both mimicking a phytase gene from a Citrobacter braakii strain. Oral administration of the phytase preparation to rats at a dose level of 0.86 g total organic solids/kg body weight/day for 13 weeks did not cause any adverse effect. The phytase preparation did not exhibit irritative potential when applied locally to the eyes of rabbits or when applied to the skin using the in vitro three-dimensional epidermis model of adult human-derived epidermal keratinocytes. Furthermore, the phytase preparation was found not to represent mutagenic or clastogenic potential in the bacterial reverse mutation assay and in the in vitro micronucleus assays. Based on the toxicological data, the large safety factors calculated under common recommended dose assumptions for broiler chickens and weaned piglets, and the fact that Aspergillus oryzae is considered a safe strain lineage, it is concluded that there are no reasons for safety concerns when using this phytase as a feed additive.     

Aspergillin PZ,a novel isoindole-alkaloid from Aspergillus awamori

Aspergillin PZ was obtained from the fermentation of Aspergillus awamori (Nakazawa) by activity-guided fractionation and purification. Its structure was elucidated on the basis of spectral data, especially by 2D NMR, and finally confirmed by an X-ray analysis. It could induce conidia of P. oryzae to deform moderately.     

Arthrinic acid, a novel antifungal polyhydroxyacid from Arthrinium phaeospermum

Arthrinic acid was isolated from solid state fermentations of the fungus Arthrinium phaeospermum. The structure of arthrinic acid was determined to be (6E,10E,14E,18E,20E)-2,3,5,9,13,17-hexahydroxy-20-(hydroxymethyl)-14,16,18,22,24-pentamethylhexacosa-6,10,14,18,20-pentaenoic acid from NMR spectroscopic studies.     

Haliangicin, a novel antifungal metabolite produced by a marine myxobacterium. 1. Fermentation and biological characteristics

Haliangicin, a novel beta-methoxyacrylate antibiotic with a conjugated tetraene moiety, was isolated from the culture broth of a marine myxobacterium. A bacterium tentatively named as Haliangium luteum required 2-3% NaCl for the growth and production of haliangicin. Haliangicin inhibits the growth of a wide spectrum of fungi but was inactive against bacteria. In mitochondrial respiratory chains, haliangicin interfered the electron flow within the cytochrome b-c1 segment.     

烟曲霉菌中抗真菌活性肽类物质的分离与纯化

目的从烟曲霉菌培养上清液中分离纯化具有抗真菌活性的肽类物质 (FIP)。方法用离子交换柱层析法分离 ,用反相高效液相色谱法进一步纯化 ,经聚丙烯酰胺凝胶电泳分析确定相对分子质量。结果从烟曲霉菌培养上清液中分离出一种具有抗真菌活性的FIP。纯化后得到高活性的精制FIP ,其相对分子质量约为 8kD ,MTT法测定结果表明 ,FIP对 5种真菌均具有明显的抗真菌效应。结论烟曲霉菌培养上清液中含有抗真菌活性的肽类物质。     

Haliangicin, a novel antifungal metabolite produced by a marine myxobacterium. 2. Isolation and structural elucidation

A novel antifungal antibiotic, haliangicin, was isolated from a culture broth of marine myxobacterium, Haliangium luteum. The planar structure of haliangicin was elucidated by spectroscopic analyses and was shown to be a new polyunsaturated compound containing beta-methoxyacrylate moiety.     

Safety evaluation of AMP deaminase from Aspergillus oryzae

Adenosine-5′-monophosphate (AMP) deaminase is an enzyme used to increase concentrations of 5’-inosine monophosphate in certain foods and beverages for flavoring purposes. One commercial source of this enzyme is Aspergillus oryzae, a filamentous fungus with a history of safe use in Asia as a fermentation organism used in the production of miso sauce and sake liquors. Noting the use of the enzyme in food intended for human consumption and potential presence at trace levels in finished goods, a series of safety studies including an in vitro Ames test and chromosome aberration assay with Chinese hamster lung fibroblasts were conducted along with a 90-day oral toxicity study in rats. AMP deaminase showed no evidence of genotoxicity in the in vitro tests. Following gavage administration of Sprague–Dawley rats at dosages of 19.8, 198.4, or 1984 mg total organic solids (TOS)/kg body weight (bw)/day for 90 days, no adverse effects on body weight gain, food consumption, hematology, clinical chemistry, urinalysis, ophthalmological and histopathological examinations were observed. The no-observed-adverse-effect level was considered to be 1984 mg TOS/kg bw/day, the highest dose tested. Results of the genotoxicity studies and subchronic rat study support the safe use of AMP deaminase produced from A. oryzae in food production.     

Restricticin, a novel glycine-containing antifungal agent

Restricticin (1) is a naturally-occurring antifungal agent which contains triene, pyran and glycine ester functionalities and is unrelated to any previously known family of natural products. This unstable compound, as well as its corresponding N,N-dimethyl derivative (2), have been produced and isolated from both solid and liquid fermentations of Penicillium restrictum. The desglycyl hydrolysis product, restrictinol (3), was produced via the hydrolysis of pure restricticin and as an artifact of the isolation of restricticin.     

Cyclopiazonic acid biosynthesis of Aspergillus flavus and Aspergillus oryzae

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations.     

YM-215343, a novel antifungal compound from Phoma sp. QN04621

Through our screening for novel antifungal compounds, YM-215343 was found in the culture extract of Phoma sp. QN04621. The structure of YM-215343 was determined by several spectroscopic experiments as a novel compound closely related to apiosporamide and fischerin. YM-215343 exhibited antifungal activity against the pathogenic fungi, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus with MIC values of 2 to approximately 16 microg/ml. It also showed cytotoxicity against HeLa S3 cells with an IC50 of 3.4 microg/ml.