Identification of a (+)-cubenene synthase from filamentous fungi Acremonium chrysogenum

Sesquiterpene synthases convert farnesyl diphosphate into various sesquiterpenes, which find wide applications in the food, cosmetics and pharmaceutical industries. Although numerous putative sesquiterpene synthases have been identified in fungal genomes, many lack biochemical characterization. In this study, we identified a putative terpene synthase AcTPS3 from Acremonium chrysogenum. Through sequence analysis and in vitro enzyme assay, AcTPS3 was identified as a sesquiterpene synthase. To obtain sufficient product for NMR testing, a metabolic engineered Saccharomyces cerevisiae was constructed to overproduce the product of AcTPS3. The major product of AcTPS3 was identified as (+)-cubenene (55.46%) by GC-MS and NMR. Thus, AcTPS3 was confirmed as (+)-cubenene synthase, which is the first report of (+)-cubenene synthase. The optimized S. cerevisiae strain achieved a biosynthesis titer of 597.3 mg/L, the highest reported for (+)-cubenene synthesis.

Influence of ultraviolet and chemical treatment on the biodegradation of low-density polyethylene and high-density polyethylene by Cephalosporium strain

In the present work, the potential of Cephalosporium strain in degrading the pre-treated (ultraviolet irradiation followed by nitric acid treatment) low-density polyethylene and high-density polyethylene films was investigated. Our observations revealed a significant weight reduction of 24.53 ± 0.73% and 18.22 ± 0.31% in pre-treated low-density polyethylene and high-density polyethylene films respectively, after 56 days of incubation with the Cephalosporium strain. Changes in the physicochemical properties of the mineral salt medium (MSM) were studied to assess the extent of biodegradation. The pH of the MSM decreased gradually during the incubation period, whereas its total dissolved solids and conductivity values increased steadily. Fourier transform infrared spectroscopy (FTIR) indicated the formation of hydroxyl and C = C groups in biodegraded low-density polyethylene films, while in the case of biodegraded high-density polyethylene films it indicated the [Formula: see text]CH₂ stretching. Furthermore, the thermogravimetric analysis (TGA) revealed an enhancement in the thermal stabilities of both the LDPE and HDPE films post the biodegradation. Modifications in the polymer surface morphologies after UV irradiation, chemical treatment, and biodegradation steps were visualized via scanning electron microscopy (SEM) analysis. All our observations confirm the ability of the Cephalosporium strain in biodegrading the pre-treated LDPE and HDPE films.

The arthrospore-related gene Acaxl2 is involved in cephalosporin C production in industrial Acremonium chrysogenum by the regulatory factors AcFKH1 and CPCR1

Cephalosporin C (CPC) production is often accompanied by a typical morphological differentiation of Acremonium chrysogenum, involving the fragmentation of its hyphae into arthrospores. The type I integral plasma membrane protein Axl2 is a central component of the bud site selection system (BSSS), which was identified as the regulatory factor involved in the hyphal septation process and arthrospore formation. Using CRISPR/Cas9 technology and homologous recombination (HR), we inserted an egfp donor DNA sequence into the Acaxl2 locus, causing the generation of the deletion strain Ac-ΔAcaxl2::eGFP from Acremonium chrysogenum FC³-5-23, the industrial producer of CPC. The mycelial morphology of the deletion strain Ac-ΔAcaxl2::eGFP was mainly composed of arthrospores with a characteristic diameter of 2-8 μm, which increased from 75% at 48h to 90% at 72h post culture and were maintained until the end of the fermentation process. However, the deletion strain showed accelerated production of CPC, and the final titer was 5573μg/ml, which was nearly three times higher than that of the control strain FC³-5-23. The up-regulation of genes related to the biosynthesis gene cluster in Ac-ΔAcaxl2::eGFP, especially the "late" genes, was one reason why its CPC production was higher than that of the original strain. Furthermore, compared with FC³-5-23, the more significant increase of genes involved in the BSSS (Acbud3 and Acbud4) in Ac-ΔAcaxl2::eGFP in the late stage of fermentation, may be responsible for this increase in arthrospore formation. Similarily, the transcription of the regulatory factors AcFKH1 and CPCR1 were also markedly increased at this time and may be the factors responsible for the regulation of CPC synthesis. These results indicated that Acaxl2 plays an important role in both arthrospore formation and CPC production, strongly implicating these regulatory factors as having pivotal links between mycelial morphology and secondary metabolite production in high-yielding A. chrysogenum. To the opposite, the axl2 gene knockout of wild strain CGMCC 3.3795 did not significantly influence the CPC production, which reflected the complexity of the secondary metabolic process and the differences in the function of axl2 gene in high- and low-yielding strains.

Acremopeptaibols A-F, 16-Residue Peptaibols from the Sponge-Derived Acremonium sp. IMB18-086 Cultivated with Heat-Killed Pseudomonas aeruginosa

Six new 16-residue peptaibols, acremopeptaibols A-F (1-6), along with five known compounds, were isolated from the cultures of the sponge-associated fungus Acremonium sp. IMB18-086 grown in the presence of the autoclaved bacterium Pseudomonas aeruginosa on solid rice medium. The peptaibol sequences were established based on comprehensive analysis of 1D and 2D NMR spectroscopic data in conjunction with HRESIMS/MS experiments. The configurations of the amino acid residues were determined by advanced Marfey's analysis. Compounds 1-6 feature the lack of the highly conserved Thr⁶ and Hyp¹⁰ residues in comparison with other members of the SF3 subfamily peptaibols. A plausible biosynthetic pathway of compounds 1-6 was proposed on the basis of genomic analysis. Compounds 1, 5, 7, and 10 exhibited significant antimicrobial activity against Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Candida albicans. Compounds 7-10 showed potent cytotoxicities against the A549 and/or HepG2 cancer cell lines.

The critical role of plasma membrane H+-ATPase activity in cephalosporin C biosynthesis of Acremonium chrysogenum

The filamentous fungus Acremonium chrysogenum is the main industrial producer of cephalosporin C (CPC), one of the major precursors for manufacturing of cephalosporin antibiotics. The plasma membrane H⁺-ATPase (PMA) plays a key role in numerous fungal physiological processes. Previously we observed a decrease of PMA activity in A. chrysogenum overproducing strain RNCM 408D (HY) as compared to the level the wild-type strain A. chrysogenum ATCC 11550. Here we report the relationship between PMA activity and CPC biosynthesis in A. chrysogenum strains. The elevation of PMA activity in HY strain through overexpression of PMA1 from Saccharomyces cerevisiae, under the control of the constitutive gpdA promoter from Aspergillus nidulans, results in a 1.2 to 10-fold decrease in CPC production, shift in beta-lactam intermediates content, and is accompanied by the decrease in cef genes expression in the fermentation process; the characteristic colony morphology on agar media is also changed. The level of PMA activity in A. chrysogenum HY OE::PMA1 strains has been increased by 50–100%, up to the level observed in WT strain, and was interrelated with ATP consumption; the more PMA activity is elevated, the more ATP level is depleted. The reduced PMA activity in A. chrysogenum HY strain may be one of the selected events during classical strain improvement, aimed at elevating the ATP content available for CPC production.

The 11α-hydroxylation of medroxyprogesterone acetate by Absidia griseolla var. igachii and Acremonium chrysogenum

Medroxyprogesterone acetate (MPA) (1) has been transformed by two filamentous fungi, including Absidia griseolla var. igachii and Acremonium chrysogenum, into 11α-hydroxy-medroxyprogesterone acetate (2) as the major metabolite. The structure of the product was identified by different spectroscopic methods (1D- and 2D-NMR, EI-MS, and elemental analysis). Moreover, a time course study determined by HPLC showed 63% and 48% yields for the metabolite by using the two mentioned fungi, respectively. Finally, the effect of the temperature and concentration of the substrate were investigated, which the optimal fermentation conditions were found to be 25 °C with a substrate concentration of 0.1% (w/v). This study reports for the first time the production of 11α-hydroxy-medroxyprogesterone acetate as a fungal biotransformation product.

Characterization of Two Polyketide Synthases Involved in Sorbicillinoid Biosynthesis by Acremonium chrysogenum Using the CRISPR/Cas9 System

Acremonium chrysogenum is an important fungal strain used for cephalosporin C production. Many efforts have been made to develop versatile genome-editing tools to better understand the mechanism of A. chrysogenum. Here, we developed a feasible and efficient CRISPR/Cas9 system. Two genes responsible for the synthesis of yellow pigments (sorbicillinoids) were chosen as targets, and plasmids expressing both the Cas9 protein and single-guide RNAs were constructed. After introducing the plasmids into the protoplasts of A. chrysogenum, 83 to 93% albino mutants harboring the expected genomic alteration, on average, were obtained. We have generated two mutant strains that respectively disrupt sorA and sorB by flexible CRISPR/Cas9 system. We further confirmed that the sorbicillinoid biosynthetic gene cluster is regulated by an autoinduction mechanism. This work will lay a solid foundation for gene function research and regulation in the sorbicillinoid biosynthetic pathway.

Ferulic acid esterase-producing lactic acid bacteria and cellulase pretreatments of corn stalk silage at two different temperatures: Ensiling characteristics, carbohydrates composition and enzymatic saccharification

The effects of Acremonium cellulase and L. plantarum A1 with ferulic acid esterase activity on corn stalk silage fermentation characteristics, carbohydrate composition and enzymatic saccharification were studied at 25 and 40 °C, respectively. Corn stalk was ensiled without additive (C), Acremonium cellulase (AC), L. plantarum A1 (Lp) and AC + Lp for 60 days. Pretreatment with Lp or AC + Lp promoted the better silage fermentation and the degradation of lignocellulose as indicated by high lactic acid and low pH and lignocellulose content compared to control silages at 25 °C. AC + Lp performed better in reducing lignocellulose and DM loss. In addition, Lp alone enhanced enzymatic saccharification of corn stalk silage. However, the influence of L. plantarum A1 on corn stalk silage was not obvious at 40 °C. Corn stalk ensiled with combined additive is a suitable pretreatment method for subsequent biofuel production at 25 °C, but addition of Acremonium cellulase alone at 40 °C may be a promising method.

A Myb transcription factor represses conidiation and cephalosporin C production in Acremonium chrysogenum

Acremonium chrysogenum is the industrial producer of cephalosporin C (CPC). We isolated a mutant (AC554) from a T-DNA inserted mutant library of A. chrysogenum. AC554 exhibited a reduced conidiation and lack of CPC production. In consistent with it, the transcription of cephalosporin biosynthetic genes pcbC and cefEF was significantly decreased in AC554. Thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) was performed and sequence analysis indicated that a T-DNA was inserted upstream of an open reading frame (ORF) which was designated AcmybA. On the basis of sequence analysis, AcmybA encodes a Myb domain containing transcriptional factor. Observation of red fluorescent protein (RFP) tagged AcMybA showed that AcMybA is naturally located in the nucleus of A. chrysogenum. Transcriptional analysis demonstrated that the AcmybA transcription was increased in AC554. In contrast, the AcmybA deleted mutant (ΔAcmybA) overproduced conidia and CPC. To screen the targets of AcmybA, we sequenced and compared the transcriptome of ΔAcmybA, AC554 and the wild-type strain at different developmental stages. Twelve differentially expressed regulatory genes were identified. Taken together, our results indicate that AcMybA negatively regulates conidiation and CPC production in A. chrysogenum.

Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease

Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum), CEF-714 (Leptosphaeria sp.), CEF-642 (Talaromyces flavus.) and CEF-193 (Acremonium sp.) isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease incidence and disease index, with the control efficacy ranging from 26% (CEF-642) to 67% (CEF-818) at 25 days (d) after inoculation. In the disease nursery, compared to controls (with disease incidence of 33.8% and disease index of 31), CEF-818, CEF-193, CEF-714 and CEF-642 provided a protection effect of 69.5%, 69.2%, 54.6% and 45.7%, respectively. Especially, CEF-818 and CEF-714 still provided well protection against Verticillium wilt with 46.9% and 56.6% or 14.3% and 33.7% at the first peak of the disease in heavily infected field, respectively (in early July). These results indicated that these endophytes not only delayed but also reduced wilt symptoms on cotton. In the harvest, the available cotton bolls of plant treated with CEF-818 and CEF-714 increased to 13.1, and 12.2, respectively. And the seed cotton yield significantly increased after seed bacterization with CEF-818 (3442.04 kg/ha) compared to untreated control (3207.51 kg/ha) by 7.3%. Furtherly, CEF-818 and CET-714 treatment increased transcript levels for PAL, PPO, POD, which leads to the increase of cotton defense reactions. Our results indicate that seed treatment of cotton plants with CEF-818 and CET-714 can help in the biocontrol of V. dahliae and improve seed cotton yield in cotton fields. This study provided a better understanding of cotton-endophyte interactions which will aid in developing effective biocontrol agents for Verticillium wilt of cotton in futhre.

Biodegradation of the Pyrethroid Pesticide Esfenvalerate by Marine-Derived Fungi

Esfenvalerate biodegradation by marine-derived fungi is reported here. Esfenvalerate (S,S-fenvalerate) and its main metabolites [3-phenoxybenzaldehyde (PBAld), 3-phenoxybenzoic acid (PBAc), 3-phenoxybenzyl alcohol (PBAlc), and 2-(4-chlorophenyl)-3-methylbutyric acid (CLAc)] were quantitatively analyzed by a validated method in triplicate experiments. All the strains (Penicillium raistrickii CBMAI 931, Aspergillus sydowii CBMAI 935, Cladosporium sp. CBMAI 1237, Microsphaeropsis sp. CBMAI 1675, Acremonium sp. CBMAI 1676, Westerdykella sp. CBMAI 1679, and Cladosporium sp. CBMAI 1678) were able to degrade esfenvalerate, however, with different efficiencies. Initially, 100 mg L(-1) esfenvalerate (Sumidan 150SC) was added to each culture in 3 % malt liquid medium. Residual esfenvalerate (64.8-95.2 mg L(-1)) and the concentrations of PBAc (0.5-7.4 mg L(-1)), ClAc (0.1-7.5 mg L(-1)), and PBAlc (0.2 mg L(-1)) were determined after 14 days. In experiments after 7, 14, 21, and 28 days of biodegradation with the three most efficient strains, increasing concentrations of the toxic compounds PBAc (2.7-16.6 mg L(-1), after 28 days) and CLAc (6.6-13.4 mg L(-1), after 28 days) were observed. A biodegradation pathway was proposed, based on HPLC-ToF results. The biodegradation pathway includes PBAld, PBAc, PBAlc, ClAc, 2-hydroxy-2-(3-phenoxyphenyl)acetonitrile, 3-(hydroxyphenoxy)benzoic acid, and methyl 3-phenoxy benzoate. Marine-derived fungi were able to biodegrade esfenvalerate in a commercial formulation and showed their potential for future bioremediation studies in contaminated soils and water bodies.

Comparative expression profiling of genes involved in primary metabolism in high-yield and wild-type strains of Acremonium chrysogenum

Cephalosporin C (CPC) productivity of Acremonium chrysogenum has been improved significantly through classical strain improvement programs. Here, we used transcription and metabolite profiling to address mechanisms underlying CPC production in a high yield (HY) strain. Transcription and metabolite profiling indicated that enzymes involved in amino acid production are higher in abundance in the HY strain. Moreover, results indicate a higher flow of precursors from the glycolysis and gluconeogenesis pathways to serine synthesis at the late stage of fermentation in the HY strain. In addition, less pyruvate would enter the TCA cycle thus favoring valine synthesis. Amino acid production would also benefit from a more active pentose phosphate pathway and γ-amino butyric acid shunt both generating NADPH. Moreover the glyoxylate pathway seems to be more active in the HY strain. These results may provide new leads for CPC strain improvement in industry.

Gliotoxin-producing endophytic Acremonium sp. from Zingiber officinale found antagonistic to soft rot pathogen Pythium myriotylum

Soft rot caused by Pythium sp. is a major cause of economic loss in ginger cultivation. Endophytic fungi isolated from Zingiber officinale were screened for its activity against the soft rot pathogen Pythium myriotylum. Among the isolates screened, an endophytic fungus which was identified as Acremonium sp. showed promising activity against the phytopathogen in dual culture. The selected fungus was cultured in large scale on solid rice media and was extracted with ethyl acetate. The crude extract was subjected to column chromatography and preparative HPLC to obtain the fraction with the antifungal activity. LC-QTOF-MS/MS analysis of this fraction done using water-acetonitrile gradient identified a mass of m/z 327 (M + H) corresponding to gliotoxin with specific fragments m/z 263, 245, 227, and 111. The result was reconfirmed in negative mode ionization. Gliotoxin is the major antagonistic peptide produced by the commercially used biocontrol agent, Trichoderma sp., which shows high antagonism against Pythium sp. The gliotoxin production by the isolated endophytic Acremonium sp. of Z. officinale shows the possible natural biocontrol potential of this endophytic fungus.

Process design and evaluation of production of bioethanol and β-lactam antibiotic from lignocellulosic biomass

To design biorefinery processes producing bioethanol from lignocellulosic biomass with dilute acid pretreatment, biorefinery processes were simulated using the SuperPro Designer program. To improve the efficiency of biomass use and the economics of biorefinery, additional pretreatment processes were designed and evaluated, in which a combined process of dilute acid and aqueous ammonia pretreatments, and a process of waste media containing xylose were used, for the production of 7-aminocephalosporanic acid. Finally, the productivity and economics of the designed processes were compared.

De novo comparative transcriptome analysis of Acremonium chrysogenum: high-yield and wild-type strains of cephalosporin C producer

β-lactam antibiotics are widely used in clinic. Filamentous fungus Acremonium chrysogenum is an important industrial fungus for the production of CPC, one of the major precursors of β-lactam antibiotics. Although its fermentation yield has been bred significantly over the past decades, little is known regarding molecular changes between the industrial strain and the wild type strain. This limits the possibility to improve CPC production further by molecular breeding. Comparative transcriptome is a powerful tool to understand the molecular mechanisms of CPC industrial high yield producer compared to wild type. A total of 57 million clean sequencing reads with an average length of 100 bp were generated from Illumina sequencing platform. 22,878 sequences were assembled. Among the assembled unigenes, 9502 were annotated and 1989 annotated sequences were assigned to 121 pathways by searching against the Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) database. Furthermore, we compared the transcriptome differences between a high-yield and a wild-type strain during fermentation. A total of 4329 unigenes with significantly different transcription level were identified, among which 1737 were up-regulated and 2592 were down-regulated. 24 pathways were subsequently determined which involve glycerolipid metabolism, galactose metabolism, and pyrimidine metabolism. We also examined the transcription levels of 18 identified genes, including 11 up-regulated genes and 7 down-regulated genes using reverse transcription quantitative -PCR (RT-qPCR). The results of RT-qPCR were consistent with the Illumina sequencing. In this study, the Illumina sequencing provides the most comprehensive sequences for gene expression profile of Acremonium chrysogenum and allows de novo transcriptome assembly while lacking genome information. Comparative analysis of RNA-seq data reveals the complexity of the transcriptome in the fermentation of different yield strains. This is an important public information platform which could be used to accelerate the research to improve CPC production in Acremonium chrysogenum.

[Functional characteristic of the CefT transporter of the MFS family involved in the transportation of beta-lactam antibiotics in Acremonium chrysogenum and Saccharomyces cerevisiae]

Vectors for the expression of the CefT transporter of the MFS family in Acremonium chrysogenum--a producer of beta-lactam antibiotic cephalosporin C--and in Saccharomyces cerevisiae as a fusion with the cyan fluorescent protein (CFP) have been created. The subcellular localization of the CefT-CFP hybrid protein in yeast cells has been investigated. It was shown that the CefT-CFP hybrid protein is capable of complementation of the qdr3, tpo 1, and tpo3 genes encoding for orthologous MFS transporters of Saccharomycetes, making the corresponding strains resistant to spermidine, ethidium bromide, and hygromycin B. High-yield strain VKM F-4081D of A. chrysogenum, expressing the cefT-cfp fusion, was obtained by an agrobacteria conjugated transfer. It was also shown that the constitutive expression of cefT in A. chrysogenum VKM F-4081D led to a change in the biosynthetic profiles of cephalosporin C and its precursors. This resulted in a 25-35% decrease in the finite product accumulated in the cultural liquid with a simultaneous increase in the concentration of its intermediators.

Fungal mn oxides supporting Mn(II) oxidase activity as effective Mn(II) sequestering materials

We examined the Mn(II)-oxidizing ability of the biogenic Mn oxide (BMO) formed in cultures ofa Mn(II)-oxidizing fungus, Acremonium strictum strain KR21-2. The newly formed BMO effectively sequestered dissolved Mn(II) mainly by oxidizing Mn(II) to insoluble Mn under air-equilibrated conditions, and this ability lasted for at least 8 days. Deaerating the BMOs, poisoning them with NaN3, or heating them all readily weakened their Mn(II) oxidation ability, indicating the involvement of enzymatic Mn(II) oxidation. There was no Mn(II)-oxidizing ability observed for mycelia cultivated without Mn(II) or for residual mycelia after the BMO phase was dissolved, suggesting the need for the oxide phase. A sodium dodecyl sulphate-polyacrylamide gel electrophoresis assay demonstrated that the oxide phase embeds the Mn(II) oxidase and thereby maintains the enzymatic activity in BMOs. Freezing at -80 degrees C preserved the Mn(II)-oxidizing ability in BMOs for at least 4 weeks, while lyophilization caused a complete loss of this ability. Based on these results, we propose that fungal Mn oxides supporting Mn(II) oxidase activity are an effective Mn(II)-sequestering material capable of oxidizing Mn(II) continuously from solutions containing no additional nutrients to maintain biological activity.

[Microbial models in screening of inhibitors of sterol biosynthesis]

On the base of previously developed microbial models high effective scheme for screening of inhibitors of sterol biosynthesis (ISB) is proposed. It is based on cultivation of halophilic bacteria Halobacterium salinarum (former Halobacterium halobium), possessing mevalonate pathway of sterol biosynthesis, and cultivation of fungus Acremonium fusidioides (former Fusidium coccineum), that is producer of steroid antibiotic fusidin (fusidic acid), which biosynthesis has great similarity (with coincidence of its initial steps till squalene formation) to cholesterol biosynthesis in human organism. In H. salinarum model ISB are revealed as compounds that inhibit test-culture growth, whereas in A. fusidioides test-system they are revealed as compounds that strongly reduce fusidin production without any visible influence on producer's growth. Mevalonate that is one of the crucial intermediates of sterol biosynthesis remove inhibition induced by many microbial metabolites that is the evidence of their action at early stages of sterol biosynthetic pathway, including HMG-CoA reductase step. Both test-systems are developed as micromethod and could be easily mechanized due to miniaturization of microbiological procedures, cultivation in sterile 96-well plates and usage of automatic micropipettes and dispensers. Effectiveness of both test-systems, as well as their sensitiveness, laboriousness and ability to give false-positive or false-negative results in ISB screening work is compared. The proposed scheme of screening of ISB includes microbial models at early steps of screening procedures and Hep G2 test-system at the late step. The preliminary screening of microbial metabolites possessing antifungal activity at initial step is compulsory. Miniaturization and mechanization of microbial processes and purification of producers' culture broth with micro- and ultrafiltration are under consideration as well.

[Screening of endophytic fungi from Huperzia serrata for acetylcholinesterase inhibitory activity and its taxonomic identification]

OBJECTIVE

To screen out fungus strains with acetylcholinesterase inhibitory activity from Huperzia serrata.

METHOD

Endophytic fungi fermentation products from 59 H. serrata strains were stained with acetylcholinesterase hydrolyzed alpha-naphthaleneacetic ethyl ester and fast blue B salt, and screened for acetylcholinesterase inhibitory activity with thin-layer chromatography-bioautography. Target strains were classified and identified through the sequence analysis on 18s rDNA and 5.8s rDNA combined with morphological characteristics.

RESULT

Fungus strain LQ2F01 from H. serrata showed positive color reaction in the screening for acetylcholinesterase inhibitory activity. The sequence analysis on 18s rDNA and 5.8s rDNA combined with morphological characteristics showed the strain LQ2F01 belonged to Acremonium.

CONCLUSION

Endophytic Fungi LQ2F01 from H. serrata shows identical acetylcholinesterase inhibitory activity with the host plant, which is of great significance to the development of natural medicines and the studies on the relationship between the endophytic gungi and the host plant.

The incubation of 13α,17-dihydroxystemodane with Cephalosporium aphidicola

The biotransformation of 13α,17-dihydroxystemodane (3) with the fungus Cephalosporium aphidicola afforded 13α,17,18-trihydroxystemodane (4), 3β,13α,17-tri-hydroxystemodane (5), 13α,17-dihydroxy-stemodan-18-oic acid (6), 3β,11β,13α,17-tetra-hydroxystemodane (7), 11β,13α,17,18-tetrahydroxystemodane (8) and 3β,13α,17,18-tetra-hydroxystemodane (9). The hydroxylation at C-18 of the substrate points to a biosynthetically-directed transformation, because aphidicolin (2) is hydroxylated at this carbon. However, the C-3(β) and C-11(β) hydroxylations seem to indicate a xenobiotic biotransformation.

[Research progress on strain improvement of Acremonium chrysogenum by genetic engineering]

Acremonium chrysogenum, cephalosporin C (CPC) producing strain, is an important industrial microorganism. CPC is used to produce 7-ACA, a major intermediate for manufacturing of many first-line anti-infectious cephalosporin-antibiotics. The fermentation level of CPC determines the production, quality and cost of its downstream products. Therefore, it is necessary to develop the strains of A. chrysogenum. Along with the development of molecular biology, genetic manipulation technique is becoming more and more important in the field of molecular breeding. This paper reviews the latest research progresses on CPC biosynthesis and its regulation. Genetic manipulations of A. chrysogenum were summarized and concluded. We suggested that strain improvement of A. chrysogenum by means of induction and expression of biosynthetic and regulatory genes, as well as exogenous genes, and further optimization could be applied to different aspects including CPC production enhancement and metabolic pathway elongation, etc. Future direction of this field is also proposed. We believed that incorporation of comparative proteomics and genomic shuffling with molecular breeding could lead the achievements close to industry promptly.

Improvement of cellulase production in cultures of Acremonium cellulolyticus using pretreated waste milk pack with cellulase targeting for biorefinery

Cellulase production in cultures of Acremonium cellulolyticus was significantly improved by using waste milk pack (MP) that had been pretreated with cellulase. When MP cellulose pretreated with cellulase (3 FPU/g MP) for 12h was used as the sole carbon source for A. cellulolyticus culture in a 3-L fermentor, the cellulase activity was 16 FPU/ml. This was 25-fold higher (0.67 FPU/ml) compared with untreated MP cellulose and was comparable to that achieved with pure cellulose (Solka Floc). As the pretreatment progressed, roughness on the surface of untreated MP cellulose became to be smooth, but development of fissures on the surface of pretreated MP cellulose was observed. Cellulase pretreatment of MP increased both the accessibility of A. cellulolyticus to the surface and number of adsorption sites of cellulase on the surface of MP cellulose, leading to improved cellulase production in the A. cellulolyticus.

Synthesis of a natural gamma-butyrolactone from nerylacetone by Acremonium roseum and Fusarium oxysporum cultures

Natural gamma-butyrolactone - (4R, 5R)-5-(4'-methyl-3'pentenyl)-4-hydroxy-5-methyl-dihydrofuran-2-one (2) was isolated as the product of microbial transformation of nerylacetone (1) by fungal strains. This product was obtained as the enantiomer (+) in high yields 24% and 61% with ee=94% and 82% by the biotransformation in the cultures of Acremonium roseum AM336 and Fusarium oxysporum AM13 respectively.

Generation of two new macrolactones through sequential biotransformation of dihydroresorcylide

Biotransformation is an effective method to generate new derivatives from natural products. Combination of various enzymes or whole-cell biocatalysts creates new opportunities for natural product biosynthesis. Dihydroresorcylide (1) is a phytotoxic macrolactone from Acremonium aeae. It was first chlorinated at C-11 by an engineered Escherichia coli BL21-CodonPlus (DE3)-RIL/pJZ54 strain that overexpresses a fungal flavin-dependent halogenase, and subsequently glycosylated at 12-OH by Beauveria bassiana ATCC 7159, giving rise to a novel derivative, 11-chloro-4'-O-methyl-12-O-beta-D-glucosyl-dihydroresorcylide (3). Although 1 can be converted into a new 4'-O-methyl-glucosylated derivative 4 by B. bassiana, this product cannot be further chlorinated by E. coli BL21-CodonPlus (DE3)-RIL/pJZ54 to afford 3. The sequence of these two biotransformation steps was thus restricted and not interchangeable. This sequential biotransformation approach can be applied to other structurally similar natural products to create novel derivatives.

[Structure peculiarities of cell walls of Acremonium chrysogenum--an autotroph of cephalosporin C]

Alterations of cell walls of Acremonium chrysogenum occurring at intensive synthesis of cephalosporin C has been studied. It is shown, using electron microscopy, that the cell wall of the cells ofATCC 11550 strain ("wild" type) became looser and thicker during growth. The cell wall of the cells of strain 26/8 (hyperautotroph of cephalosporin C) considerably degraded by the end of the stationary phase. Biochemical analysis has shown that these alterations entailed decrease of the proteins' content covalently or noncovalently linked with the polysaccharides of cell walls of both strains. An increase of sensitivity of cell walls of the strain-superproducer to an activity of lytic enzymes of chitinase, laminarinase, proteinase K, and lyticase preparation has been observed during the growth, but this increase has not been found in the case of "wild" type strain. The obtained results evidence to the structure failure of the cell wall of A. chrysogenum entailing the intensive creation of antibiotic.

Quantitative metabolic flux analysis revealed uneconomical utilization of ATP and NADPH in Acremonium chrysogenum fed with soybean oil

A metabolic network was constructed for the Acremonium chrysogenum cultivation fed with soybean oil. Metabolic flux analysis indicated that the shift from exponential growth to rapid cephalosporin C (CPC) formation was accompanied by 1.63- and 5-fold carbon flux enlargement in TCA cycle and glyoxylate by-pass, respectively. The flux via pentose phosphate pathway branch was little affected during the rapid CPC formation period; the contributory explanation was that 35.6% of NADPH was consumed in the dissimilation of fatty acids. Estimation of NADPH, ATP generation, and consumption demonstrated that, with soybean oil as carbon source in rapid CPC formation phase, the NADPH consumed in fatty acid catabolism was fourfold greater than that used in the CPC biosynthesis-relevant part; simultaneously, more than 90% energy spent was not directly related to the CPC formation. Therefore, the improvement of CPC production yield through optimization of the NADPH, ATP generation, and consumption was put forward.

Stimulation of cephalosporin C production in Acremonium chrysogenum M35 by glycerol

In this study, the effects of glycerol on cephalosporin C production by Acremonium chrysogenum M35 were evaluated. The addition of glycerol increased cephalosporin production by up to 12-fold. Glycerol caused the upregulation of the transcription of the isopenicillin synthase (pcbC) and transporter (cefT) genes in early exponential phase, and affected the cell morphology since hyphal fragments differentiated into arthrospores. These results indicate that glycerol effectively enhances cephalosporin C production via stimulation of cell differentiation.

Fungal PAH-metabolites resist mineralization by soil microorganisms

This study investigated the mineralization of water-soluble polycyclic aromatic hydrocarbon (PAH) metabolites produced by the soil fungus Cunninghamella elegans. Eleven soil fungi were screened for their ability to metabolize (14)C-phenanthrene, (14)C-fluoranthene, and (14)C-pyrene into water-soluble compounds. Eight fungi produced water-soluble metabolites from all or some of the PAHs. The composition of the water-soluble PAH-metabolites from the most effective solubilizer C. elegans was analyzed by an ultraperformance liquid chromatograph interfaced to a quadrupole time-of-flight mass spectrometer. Thirty-eight metabolites were detected. All of 34 identified metabolites were sulfate-conjugated. The mineralization of (14)C-metabolites, produced by C. elegans, was compared to mineralization of the parent (14)C-PAHs in soil slurries. It was hypothesized that the increased bioavailability and metabolic activation of the metabolites would increase mineralization in soil slurries compared to mineralization of the parent PAHs. Unexpectedly, the mineralization of the (14)C-metabolites was in all cases extremely slow compared to the mineralization of the parent (14)C-PAHs. Slow (14)C-metabolite mineralization was not caused by metabolite toxicity, neither was cometabolic mineralization of (14)C-metabolites stimulated by the presence of active PAH-degraders. High water solubility, low lipophilicity, and extremely slow mineralization of the metabolites indicate a potential problem of leaching of fungal PAH-metabolites to the groundwater.

[The concentration dynamics of inorganic polyphosphates during the cephalosporin C synthesis by Acremonium chrysogenum]

The contents of five fractions of energy-rich inorganic polyphosphates (polyPs), ATP, and H(+)-ATPase activity in the plasma membrane were determined in a low-activity cephalosporin C (cephC) producer Acremonium chrysogenum ATCC 11550 and selected highly efficient producer strain 26/8 grown on glucose or a synthetic medium providing for active synthesis of this antibiotic. It was shown that strain 26/8 on the synthetic medium produced 26-fold higher amount of cephC as compared with strain ATCC 11550. This was accompanied by a drastic decrease in the cell contents of ATP and the high-molecular-weight fractions polyP2, polyP3, and polyPS with a concurrent increase in the low-molecular-weight fraction polyP1. These data suggest that polyPs are involved in the cephC synthesis as a source of energy. H(+)-ATPase activity insignificantly changed at both low and high levels of cephC production. This confirms the assumption that A. chrysogenum has other alternative antibiotic transporters in addition to cefT. The obtained results can be used for optimizing commercial-scale cephC biosynthesis.

Atomic-scale structure of biogenic materials by total X-ray diffraction: a study of bacterial and fungal MnOx

Biogenic materials are produced by microorganisms and are typically found in a nanophase state. As such, they are difficult to characterize structurally. In this report, we demonstrate how high-energy X-ray diffraction and atomic pair distribution function analysis can be used to determine the atomic-scale structures of MnO(x) produced by bacteria and fungi. These structures are well-defined, periodic, and species-specific, built of Mn-O(6) octahedra forming birnessite-type layers and todorokite-type tunnels, respectively. The inherent structural diversity of biogenic material may offer opportunities for practical applications.

Antimicrobial activity of pyrrocidines from Acremonium zeae against endophytes and pathogens of maize

Acremonium zeae produces pyrrocidines A and B, which are polyketide-amino acid-derived antibiotics, and is recognized as a seedborne protective endophyte of maize which augments host defenses against microbial pathogens causing seedling blights and stalk rots. Pyrrocidine A displayed significant in vitro activity against Aspergillus flavus and Fusarium verticillioides in assays performed using conidia as inoculum, with pyrrocidine A being more active than B. In equivalent assays performed with conidia or hyphal cells as inoculum, pyrrocidine A revealed potent activity against major stalk and ear rot pathogens of maize, including F. graminearum, Nigrospora oryzae, Stenocarpella (Diplodia) maydis, and Rhizoctonia zeae. Pyrrocidine A displayed significant activity against seed-rotting saprophytes A. flavus and Eupenicillium ochrosalmoneum, as well as seed-infecting colonists of the phylloplane Alternaria alternata, Cladosporium cladosporioides, and Curvularia lunata, which produces a damaging leaf spot disease. Protective endophytes, including mycoparasites which grow asymptomatically within healthy maize tissues, show little sensitivity to pyrrocidines. Pyrrocidine A also exhibited potent activity against Clavibacter michiganense subsp. nebraskense, causal agent of Goss's bacterial wilt of maize, and Bacillus mojaviense and Pseudomonas fluorescens, maize endophytes applied as biocontrol agents, but were ineffective against the wilt-producing bacterium Pantoea stewartii.

The specific inhibitory effect of demethoxydehydroaltenusin, a derivative of dehydroaltenusin, on mammalian DNA polymerase alpha

In the screening of selective inhibitors of eukaryotic DNA polymerases (pols), dehydroaltenusin from the fungus Acremonium sp. was found to be an inhibitor of pol alpha. The present study succeeded in chemically synthesizing dehydroaltenusin, and the compound strongly inhibited calf pol alpha activity and weakly suppressed rat pol beta activity, with IC50 values of 0.68 and 64 microM, respectively. We purified or synthesized various slightly modified derivatives of dehydroaltenusin, and using these, investigated the relationship between chemical structure and the inhibitory effects. These results suggest that the ketone group at the 5'-position in dehydroaltenusin is essential for pol inhibitory activity, and the group at the 5-position is important for the specificity of pol alpha inhibition. Demethoxydehydroaltenusin was found to be the most specific pol alpha inhibitor among the prepared derivatives, and the IC50 values for pols alpha and beta were 0.24 and 89 microM, respectively. This compound did not influence the activities of other replicative pols such as pols delta and epsilon, and also demonstrated no effect on pol alpha activity from another vertebrate, fish and a plant species. Demethoxydehydroaltenusin also had no influence on the other pols and DNA metabolic enzymes tested. Therefore, demethoxydehydroaltenusin is of interest as a mammalian pol alpha-selective inhibitor as a 'chemical knockout agent' in vitro and in vivo.

Characterisation of uranium(VI) sorption by two environmental fungal species using gamma spectrometry

Uranium(VI) sorption by two highly uranium-resistant air-borne fungi in a low-pH medium was measured by means of gamma spectrometry. Growth kinetics and stoichiometry of the two fungal species were also studied. Results show acceptable growth rates in synthetic medium with glucose and ammonia as carbon and nitrogen sources, respectively. Typical oxidative metabolism of carbohydrates was found. In vivo uptake of the radionuclide was negligible, but biosorption dry biomass presented a remarkable performance. The fungal strains showed potential for use in bioremediation.

Acremonium zeae, a protective endophyte of maize, produces dihydroresorcylide and 7-hydroxydihydroresorcylides

Acremonium zeae has been characterized as a protective endophyte of maize and displays antifungal activity against other fungi. Pyrrocidines A and B were discovered to be the metabolites accounting for this activity. During a population survey of A. zeae isolates from maize seeds produced in nine states to determine their ability to produce pyrrocidines, another metabolite of A. zeae, unrelated to the pyrrocidines, was found to have widespread occurrence (105 of 154 isolates) and to be produced in amounts comparable to the pyrrocidines. Further chemical studies of fermentation extracts of an A. zeae isolate (NRRL 45893) from maize led to the identification of a new compound, dihydroresorcylide, the saturated analogue of cis-resorcylide. Also identified were the two diastereomers of 7-hydroxydihydroresorcylide. Dihydroresorcylide and pyrrocidines A and B were detected by LC-APCI-MS in symptomatic maize kernels from ears that were wound-inoculated in the milk stage with A. zeae NRRL 34559.

The utilization of beet molasses as a novel carbon source for cephalosporin C production by Acremonium chrysogenum: Optimization of process parameters through statistical experimental designs

In this work, cephalosporin C (CPC) production on pilot scale fermenters of 600l capacity with 350l working volume by Acremonium chrysogenum EMCC 904 was performed. The effects of fermentation medium composition, inoculum concentration, initial pH and aeration rate on CPC production by A. chrysogenum strain was investigated by using response surface methodology (RSM). The Plackett-Burman design which involves two concentrations of each nutrient was effective in searching for the major medium components promoting CPC production. Under our experimental conditions; Soya oil, beet molasses and corn steep liquor were found to be the major factors contributing to the antibiotic production. Subsequently, a Box-Behnken design was used for outlining the concentration of the most effective medium constituents. Estimated optimum composition for the production of CPC was as follows: soya oil, 40g/l; beet molasses, 180g/l; and corn steep liquor, 330g/l. The central composite design was used for outlining the optimum values of the fermentation parameters. Estimated optimum values for the production of CPC are as follows: inoculum level, 10(5.5)spores/ml; initial pH, 4.3; and aeration rate, 9364ml/min.

Accumulation of copper by Acremonium pinkertoniae, a fungus isolated from industrial wastes

Acremonium pinkertoniae isolated from zinc wastes was studied to understand the mechanisms that allow living organisms to thrive in polluted environments and the possible role of the fungus in the redistribution and cycling of copper. The fungus was cultured on solid media supplemented with copper sulfate at increasing concentrations. At high doses it was observed that the mycelia acquired a characteristic blue color. This was accompanied by morphological changes and the formation of crystalloid structures within thickened cell walls. The material was further analysed with EDX, X-ray powder diffraction and IR spectroscopy. It was demonstrated that A. pinkertoniae is able to accumulate over 20% dry weight of copper by what probably is a chitin-glucan complex.

Efficient Cellulase Production by the Filamentous Fungus Acremonium cellulolyticus

Cellulase production was investigated in a culture of a strain of Acremonium cellulolyticus. The medium components were optimized for the improvement of cellulase production. The maximum production of cellulolytic enzymes was obtained in a medium containing (grams per liter) 50 Solka Floc, 5 (NH4)2SO4, 24 KH2PO4, 4.7 potassium tartrate hemihydrate, 1.2 MgSO4.7H2O, 1 Tween 80, 4 urea, 0.01 ZnSO4.7H2O, 0.01 MnSO4.6H2O, and 0.01 CuSO4.7H2O, with a pH of 4.0. In the flask culture, 15.5 filter paper units (FPU)/mL of maximum cellulase activity was obtained, 17.42 FPU/mL in a 7-L bioreactor, and 13.08 FPU/mL in a 50-L scale bioreactor for 4-8 d at 30 degrees C. Average production rates were 1.94 FPU/mL.d in flasks, 2.86 FPU/mL.d in the 7-L bioreactor, and 2.56 FPU/mL.d in the 50-L bioreactor. Cellulase production on a small scale was successfully reproduced in the 50-L pilot scale bioreactor. Saccharification activity from A. cellulolyticus was compared with cellulolytic enzymes produced by other strains. The A. cellulolyticus culture broth had a comparable saccharification yield in comparison with those of other Trichoderma enzymes (GC220 or Cellulosin T2) under the same total cellulase activity. Its saccharification yield (percent of released reducing sugar to used dried substrate) was 60%, and its glucose content was 83%.

New Culture Approaches for Yessotoxin Production from the Dinoflagellate Protoceratium reticulatum

Fed-batch and perfusion cultures were carried out in a traditional glass 2-L bioreactor with the toxic dinoflagellate Protoceratium reticulatum. The maximum cell concentration obtained was 2.3 x 105 cell.mL-1, which is almost 1 order of magnitude higher than the maximum previously referenced for this species. L1 medium was shown to be clearly deficient in nitrate and phosphate for this strain, and addition of highly concentrated aliquots of these nutrients allowed higher cell concentrations to be obtained. This species consumed high amounts of nitrate and phosphate, 2.1 x 10-3 and 2.3 x 10-4 micromol.h-1.cell-1, respectively. However, this consumption produced a very low number of cells compared to other classes of microalgae, indicating that this species is, like other dinoflagellates, a poor competitor in terms of utilization of inorganic nutrients. Higher production of toxins and pigments was strongly associated with cell number in the culture, with maximum values of 700 ng.mL-1 and 1321 microg.mL-1, respectively. Most yessotoxins remained within the cells and not in the cell-free culture medium, and their production was not related to either the age of the culture or the cell growth phase.

Metabolites from the fungusCephalosporium sp. AL031

A new pyrone derivative, 7, 9-dihydroxy-10-methyl-2H, 4aH, 6H, 10bH-pyrano[5,6-c][2]ben-zopyran-2,6-dione (1), was isolated from a culture broth of a strain of the fungus Cephalosporium sp. AL031, together with three known compounds, 3-acetyl-7-hydroxy-5-methoxyl-3H-isobenzofuran-1-one (2), vermopyrone (3), and 5-methylmellein (4). Their structures were elucidated by spectroscopic analysis including MS and 2D-NMR. Compounds 2, 3, and 4 are reported for the first time from fermentation broth of this fungus through the present study.

Characterisation of 3-methylorcinaldehyde synthase (MOS) in Acremonium strictum: first observation of a reductive release mechanism during polyketide biosynthesis

Isolation and sequencing of a PKS gene isolated from xenovulene-producing cultures of Acremonium strictum indicated the presence of NT-, KS-, AT-, PT-, C-MeT- and R-domains; heterologous expression in Aspergillus oryzae resulted in the production of 3-methylorcinaldehyde, demonstrating the role of the terminal reductase domain in product release.

An efficient fungal RNA-silencing system using the DsRed reporter gene

In filamentous fungi, RNA silencing is an attractive alternative to disruption experiments for the functional analysis of genes. We adapted the gene encoding the autofluorescent DsRed protein as a reporter to monitor the silencing process in fungal transformants. Using the cephalosporin C producer Acremonium chrysogenum, strains showing a high level of expression of the DsRed gene were constructed, resulting in red fungal colonies. Transfer of a hairpin-expressing vector carrying fragments of the DsRed gene allowed efficient silencing of DsRed expression. Monitoring of this process by Northern hybridization, real-time PCR quantification, and spectrofluorometric measurement of the DsRed protein confirmed that downregulation of gene expression can be observed at different expression levels. The usefulness of the DsRed silencing system was demonstrated by investigating cosilencing of DsRed together with pcbC, encoding the isopenicillin N synthase, an enzyme involved in cephalosporin C biosynthesis. Downregulation of pcbC can be detected easily by a bioassay measuring the antibiotic activity of individual strains. In addition, the presence of the isopenicillin N synthase was investigated by Western blot hybridization. All transformants having a colorless phenotype showed simultaneous downregulation of the pcbC gene, albeit at different levels. The RNA-silencing system presented here should be a powerful genetic tool for strain improvement and genome-wide analysis of this biotechnologically important filamentous fungus.

Antimicrobial metabolites produced by an intertidal Acremonium furcatum

In a screening for antimicrobial metabolites, amides of D-allo- and L-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities.

Manganese(IV) oxide production by Acremonium sp. strain KR21-2 and extracellular Mn(II) oxidase activity

Ascomycetes that can deposit Mn(III, IV) oxides are widespread in aquatic and soil environments, yet the mechanism(s) involved in Mn oxide deposition remains unclear. A Mn(II)-oxidizing ascomycete, Acremonium sp. strain KR21-2, produced a Mn oxide phase with filamentous nanostructures. X-ray absorption near-edge structure (XANES) spectroscopy showed that the Mn phase was primarily Mn(IV). We purified to homogeneity a laccase-like enzyme with Mn(II) oxidase activity from cultures of strain KR21-2. The purified enzyme oxidized Mn(II) to yield suspended Mn particles; XANES spectra indicated that Mn(II) had been converted to Mn(IV). The pH optimum for Mn(II) oxidation was 7.0, and the apparent half-saturation constant was 0.20 mM. The enzyme oxidized ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] (pH optimum, 5.5; Km, 1.2 mM) and contained two copper atoms per molecule. Moreover, the N-terminal amino acid sequence (residues 3 to 25) was 61% identical with the corresponding sequence of an Acremonium polyphenol oxidase and 57% identical with that of a Myrothecium bilirubin oxidase. These results provide the first evidence that a fungal multicopper oxidase can convert Mn(II) to Mn(IV) oxide. The present study reinforces the notion of the contribution of multicopper oxidase to microbially mediated precipitation of Mn oxides and suggests that Acremonium sp. strain KR21-2 is a good model for understanding the oxidation of Mn in diverse ascomycetes.

Microbial Transformation of Nandrolone Decanoate by Acremonium Strictum

Estr-4-en-3,17-dione II, 17beta-hydroxyestr-4-en-3-one III, 15alpha-hydroxyestr-4-en-3,17-dione IV, and 15alpha,17beta-dihydroxyestr-4-en-3-one V were produced by microbial transformation of nandrolone decanoate I in the culture of Acremonium strictum PTCC 5282. Bioconversion characteristics observed were ester hydrolysis, oxidation, and hydroxylation. Each microbial product was purified chromatographically and characterized on the basis of spectral data obtained from (1)H-NMR,( 13)C-NMR, FT-IR, MS, and physical constants such as melting point and optical rotation.

Involvement of lignocellulolytic enzymes in the decomposition of leaf litter in a subtropical forest

The involvement of ligninolytic and cellulolytic enzymes, such as laccase, lignin peroxidase, manganese peroxidase, carboxymethylcellulase (CMCase), and filter paper activity (FPA), in the decomposition process of leaf litter driven by 6 soil-inhabiting fungi imperfecti was studied under solid-state fermentations. All the tested fungi exhibited varied production profiles of lignocellulolytic enzymes and each caused different losses in total organic matter (TOM) during decomposition. Based on the results, the 6 fungi could be divided into 2 functional groups: Group 1 includes Alternaria sp., Penicillium sp., Acremonium sp., and Trichoderma sp., and Group 2 includes Pestalotiopsis sp. and Aspergillus fumigatus. Group 1, with higher CMCase and FPA activities, showed a higher decomposition rate than the fungi of Group 2 over the first 16 d, and thereafter the cellulolytic activities and decomposition rate slowed down. Group 2 showed the maximum and significantly higher CMCase and FPA activities than those of the Group 1 fungi during the later days. This, combined with the much higher laccase activity, produced a synergistic reaction that led to a much faster average mass loss rate. These results suggest that the fungi of Group 1 are efficient decomposers of cellulose and that the fungi of Group 2 are efficient decomposers of lignocellulose. During cultivation, Pestalotiopsis sp. produced an appreciable amount of laccase activity (0.56+/-0.09 U/ml) without the addition of inducers and caused a loss in TOM of 38.2%+/-3.0%, suggesting that it has high potential to be a new efficient laccase-producing fungus.

New Dihydrobenzofuran Derivative, Awajanoran, from Marine-derived Acremonium sp. AWA16-1

Awajanoran (1), a new dihydrobenzofuran derivative, was isolated from an agar-culture of Acremonium sp. AWA16-1, which had been isolated from sea mud collected at Awajishima Island in Japan. The structure of 1 was elucidated on the basis of a spectroscopic analysis. This compound inhibited the growth of A549 cells, the human lung adenocarcinoma cell line, with an IC50 value of 17 microg/ml, and also showed antimicrobial activity.

Studies on the microbial transformation of androst-1,4-dien-3,17-dione with Acremonium strictum

The strain of Acremonium strictum PTCC 5282 was applied to investigate the biotransformation of androst-1,4-dien-3,17-dione (I; ADD). Microbial products obtained were purified by preparative TLC and the pure metabolites were characterized on the basis of their spectroscopic features (13C NMR, 1H NMR, FTIR, MS) and physical constants (melting points and optical rotations). The 15 alpha-Hydroxyandrost-1,4-dien-3,17-dione (II), 17 beta-hydroxyandrost-1,4-dien-3-one (III), androst-4-en-3,17-dione (IV; AD), 15 alpha-hydroxyandrost-4-en-3,17-dione (V), 15 alpha,17 beta-dihydroxyandrost-1,4-dien-3-one (VI) and testosterone (VII) were produced during this fermentation. Formation of the 15 alpha,17 beta-dihydroxy derivative of ADD is reported for the first time during steroid biotransformation. The bioconversion reactions observed were 1,2-hydrogenation, 15 alpha-hydroxylation and 17-ketone reduction. From the time course profile of this biotransformation, ketone reduction and 1,2-hydrogenation were observed from the first day of fermentation while 15 alpha-hydroxylation occurred from the third day. Optimum concentration of the substrate, which gave the maximum bioconversion efficiency, was 0.5 mg ml(-1) in one batch. The highest yield of the microbial products recorded in this work was achieved within the pH range 6.5-7.3 and at the temperature of 27 degrees C.

Production of fungal antibiotics using polymeric solid supports in solid-state and liquid fermentation

The use of inert absorbent polymeric supports for cellular attachment in solid-state fungal fermentation influenced growth, morphology, and production of bioactive secondary metabolites. Two filamentous fungi exemplified the utility of this approach to facilitate the discovery of new antimicrobial compounds. Cylindrocarpon sp. LL-Cyan426 produced pyrrocidines A and B and Acremonium sp. LL-Cyan416 produced acremonidins A-E when grown on agar bearing moist polyester-cellulose paper and generated distinctly different metabolite profiles than the conventional shaken or stationary liquid fermentations. Differences were also apparent when tenfold concentrated methanol extracts from these fermentations were tested against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria, and zones of inhibition were compared. Shaken broth cultures of Acremonium sp. or Cylindrocarpon sp. showed complex HPLC patterns, lower levels of target compounds, and high levels of unwanted compounds and medium components, while agar/solid support cultures showed significantly increased yields of pyrrocidines A and B and acremonidins A-E, respectively. This method, mixed-phase fermentation (fermentation with an inert solid support bearing liquid medium), exploited the increase in surface area available for fungal growth on the supports and the tendency of some microorganisms to adhere to solid surfaces, possibly mimicking their natural growth habits. The production of dimeric anthraquinones by Penicillium sp. LL-WF159 was investigated in liquid fermentation using various inert polymeric immobilization supports composed of polypropylene, polypropylene cellulose, polyester-cellulose, or polyurethane. This culture produced rugulosin, skyrin, flavomannin, and a new bisanthracene, WF159-A, after fermentation in the presence and absence of polymeric supports for mycelial attachment. The physical nature of the different support systems influenced culture morphology and relative metabolite yields, as determined by HPLC analysis and measurement of antimicrobial activity. The application of such immobilized-cell fermentation methods under solid and liquid conditions facilitated the discovery of new antibiotic compounds, and offers new approaches to fungal fermentation for natural product discovery.

Morphology and productivity of filamentous fungi

Cultivation processes involving filamentous fungi have been optimised for decades to obtain high product yields. Several bulk chemicals like citric acid and penicillin are produced this way. A simple adaptation of cultivation parameters for new production processes is not possible though. Models explaining the correlation between process-dependent growth behaviour and productivity are therefore necessary to prevent long-lasting empiric test series. Yet, filamentous growth consists of a complex microscopic differentiation process from conidia to hyphae resulting in various macroscopically visible appearances. Early approaches to model this morphologic development are recapitulated in this review to explain current trends in this area of research. Tailoring morphology by adjusting process parameters is one side of the coin, but an ideal morphology has not even been found. This article reviews several reasons for this fact starting with nutrient supply in a fungal culture and presents recent advances in the investigation of fungal metabolism. It illustrates the challenge to unfold the relationship between morphology and productivity.

Fumigaclavine C, an fungal metabolite, improves experimental colitis in mice via downregulating Th1 cytokine production and matrix metalloproteinase activity

In the present paper, the effect of Fumigaclavine C, a fungal metabolite, on experimental colitis was examined. Fumigaclavine C, when administered intraperitoneally once a day, significantly reduced the weight loss and mortality rate of mice with experimental colitis induced by intrarectally injection of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). This compound also markedly alleviated the macroscopic and microscopic appearances of colitis. Furthermore, Fumigaclavine C, given both in vivo and in vitro, showed a marked inhibition on the expression of several inflammatory cytokines, including IL-1beta, IL-2, IL-12alpha, IFN-gamma, TNF-alpha as well as MMP-9 in sacral lymph node cells, colonic patch lymphocytes and colitis tissues from the TNBS colitis mice. Meanwhile, the compound caused a dose-dependent reduction in IL-2 and IFN-gamma from the lymphocytes at the protein level and MMP-9 activity. These results suggest that Fumigaclavine C may alleviate experimental colitis mainly via down-regulating the production of Th1 cytokines and the activity of matrix metalloproteinase.