Fungus Acremonium Research Articles

Cellulose-inducible xylanase Xyl10A from Acremonium cellulolyticus: Purification, cloning and homologous expression

Cellulose-inducible endo-β-1,4-xylanase (Xyl10A) from the mesophilic fungus Acremonium cellulolyticus was purified, characterized, and expressed by a homologous expression system. A. cellulolyticus CF-2612 produces a high level of xylanase upon induction by Solka-Floc cellulose. To identify this xylanase, the major fraction showing xylanase activity was purified from the CF-2612 culture supernatant, and its gene was identified from the genome sequence. Amino acid sequence homology of Xyl10A revealed that the purified xylanase, designated Xyl10A, exhibited significant homology to family 10 of the glycoside hydrolases (GH10), possessing a cellulose-binding module 1 in the C-terminal region. The xyl10A gene was cloned and expressed in A. cellulolyticus under the control of a glucoamylase promoter. Two recombinant Xyl10As (rXyl10A-I, 53kDa, and rXyl10A-II, 51kDa) were purified that have slightly different molecular weights based on SDS–PAGE. The rXyl10As had the same physicochemical and enzymatic properties as wtXyl10A: high thermostability (Tm 80.5°C), optimum pH 5.0 and specific activity 232–251U/mg for birchwood xylan. The molecular weights of N-deglycosylated rXyl10As were consistent with that of wild-type Xyl10A (wtXyl10A, 51kDa).

Direct ethanol production from glucose, xylose and sugarcane bagasse by the corn endophytic fungi Fusarium verticillioides and Acremonium zeae

Production of ethanol with two corn endophytic fungi, Fusarium verticillioides and Acremonium zeae, was studied. The yield of ethanol from glucose, xylose and a mixture of both sugars were 0.47, 0.46 and 0.50g/g ethanol/sugar for F. verticillioides and 0.37, 0.39 and 0.48g/g ethanol/sugar for A. zeae. Both fungi were able to co-ferment glucose and xylose. Ethanol production from 40g/L of pre-treated sugarcane bagasse was 4.6 and 3.9g/L for F. verticillioides and A. zeae, respectively, yielding 0.31g/g of ethanol per consumed sugar. Both fungi studied were capable of co-fermenting glucose and xylose at high yields. Moreover, they were able to produce ethanol directly from lignocellulosic biomass, demonstrating to be suitable microorganisms for consolidated bioprocessing.

Polyphosphates and exopolyphosphatase activities in the yeast Saccharomyces cerevisiae under overexpression of homologous and heterologous PPN1 genes

The role of exopolyphosphatase PPN1 in polyphosphate metabolism in fungi has been studied in strains of Saccharomyces cerevisiae transformed by the yeast PPN1 gene and its ortholog of the fungus Acremonium chrysogenum producing cephalosporin C. The PPN1 genes were expressed under a strong constitutive promoter of the gene of glycerol aldehyde-triphosphate dehydrogenase of S. cerevisiae in the vector pMB1. The yeast strain with inactivated PPN1 gene was transformed by the above vectors containing the PPN1 genes of S. cerevisiae and A. chrysogenum. Exopolyphosphatase activity in the transformant with the yeast PPN1 increased 28- and 11-fold compared to the mutant and parent PPN1 strains. The amount of polyphosphate in this transformant decreased threefold. Neither the increase in exopolyphosphatase activity nor the decrease in polyphosphate content was observed in the transformant with the orthologous PPN1 gene of A. chrysogenum, suggesting the absence of the active form of PPN1 in this transformant.

Secondary Metabolites of the Sponge-Derived Fungus Acremonium persicinum

This study reports the isolation and characterization of six new acremine metabolites, 5-chloroacremine A (4), 5-chloroacremine H (5), and acremines O (6), P (7), Q (8), and R (9), together with the known acremines A (1), F (2), and N (3) from the fungus Acremonium persicinum cultured from the marine sponge Anomoianthella rubra. The relative configuration of acremine F (2) was determined by analyses of proton coupling constant values and NOESY data, and the absolute configuration confirmed as (1S, 4S, 6R) by X-ray crystallographic analysis of the borate ester derivative 15. Acremines O, P, and R were each shown to be of 8R configuration by ¹H NMR analyses of MPA esters. The relative configurations suggested for acremines P and Q were each deduced by molecular modeling together with NOESY and coupling constant data. The ³J(H-C) values in acremine P were measured using the pulse sequence EXSIDE, and the observed ³J(H8-C4) of 5.4 Hz and small ³J(H-C) values (<1.5 Hz) from H-8 to C-10 and C-11 were fully consistent with stereoisomer 7a. For acremine Q, NOESY data combined with molecular modeling established the preferred diastereomer 8a.

Productivity and quality of seeds of Fagopyrum esculentum Moench under treatment with virescenosides a and a sum of glycosides of marine fungus Acremonium striatisporum at super low concentrations

The paper presents results of the experimental studies of the effect of new growth regulators that are capable of stimulating the development, growth, and physiological processes of plants Fagopyrum esculentum Moench. It is shown that, under treatment of seeds and plants of the buckwheat varieties Izumrud and Pri 10 with diterpene glycosides virescenoside A and a sum of diterpene glycosides isolated from the marine fungus Acremonium striatisporum KMM 4401, their stimulating effect on the growth of sprout roots, yield, and seed quality is observed.

Transport of substrates into peroxisomes: the paradigm of β-lactam biosynthetic intermediates

Peroxisomes are ubiquitous organelles that enclose catalases, fatty acid-oxidizing enzymes, and a variety of proteins involved in different cellular processes. Interestingly, the late enzymes involved in penicillin biosynthesis, and the isopenicillin N epimerization enzymes involved in cephalosporin biosynthesis are located inside peroxisomes in the producer fungi Penicillium chrysogenum and Acremonium chrysogenum. Peroxisome proteins are targeted to those organelles by peroxisomal targeting signals located at the C-terminus (PTS1) or near the N-terminal end (PTS2) of those proteins. Peroxisomal membrane proteins (PMPs) are largely recruited by the interaction with specific sequences in the Pex19 protein. The compartmentalization into peroxisomes of several steps of the biosynthesis of penicillin, cephalosporin, and other secondary metabolites raises the question of how the precursors and/or intermediates of the biosynthesis of β-lactam antibiotics are transported into peroxisomes and the mechanisms of secretion of the final products (penicillin or cephalosporin) from peroxisomes to the extracellular medium. Recent advances in peroxisome proteomics, immunoelectron microscopy, and fluorescence labeling have shown that the transport of these intermediates is mediated by membrane proteins of the major facilitator superfamily class (drug/H+ antiporters) containing 12 transmembrane-spanning domains (TMS). In some cases, the transport of the substrates (e.g., fatty acids) or intermediates may be mediated by ATP-binding cassette (ABC) transporters. Knowledge on the transport and secretion mechanisms is of paramount importance to understand the complex mechanisms of cell differentiation and their crosstalk with the biosynthesis of different secondary metabolites that act as biochemical signals between the producer cells and also as communication signals with competing microorganisms (e.g., antimicrobial agents or plant elicitors).

High-coverage gene expression profiling analysis of the cellulase-producing fungus Acremonium cellulolyticus cultured using different carbon sources

The gene expression of a cellulase-producing fungus, Acremonium cellulolyticus, was investigated after culturing with three different carbon sources: glycerol, lactose, and Solka-Floc powdered cellulose (SF). High-coverage gene expression profiling (HiCEP) analysis, a method requiring no prior sequence knowledge, was used to screen genes upregulated at the early stage of cellulase production. SF was used as a strong inducer of cellulase production, lactose was used as an inducer of the expression of cellulase genes at the early stage of the culture, and glycerol was used as a negative control. Approximately 15,000 transcript-derived fragments (TDFs) were detected in each sample prepared from the culture grown for 16h. Based on the expression profiles of the cultured cells, 36 fragments upregulated in both the SF and lactose cultures were selected and sequenced. The deduced gene products of 31 TDFs were likely related to biomass degradation, sugar metabolism, transcriptional regulation, protein modification and metabolism, cell wall recycling, fatty acid and polyketide biosynthesis, and other functions. Quantitative real-time reverse-transcriptase polymerase chain reaction analysis verified that almost all of the transcripts obtained by HiCEP analysis were upregulated in the SF and lactose cultures grown for 18h. Some of the TDFs in the SF culture were further upregulated over the course of 72h. The gene products from these TDFs would provide insight into improving the cellulase productivity of A. cellulolyticus.

Metabolites of marine isolate of the fungus Acremonium roseum

Metabolites of marine isolate of the fungus Acremonium roseum

Production of Hesperetin Using a Covalently Multipoint Immobilized Diglycosidase from Acremonium sp. DSM24697

The diglycosidase α-rhamnosyl-β-glucosidase (EC 3.2.1.168) from the fungus Acremonium sp. DSM24697 was immobilized on several agarose-based supports. Covalent multipoint immobilization onto glyoxyl-activated agarose was selected as the more stable preparation at high concentration of dimethyl sulfoxide (DMSO) and high temperature. The optimal conditions for the immobilization process involved an incubation of the enzyme with agarose beads containing 220 μmol of glyoxyl groups per gram at pH 10 and 25°C for 24 h. The hydrolysis of hesperidin carried out in 10% v/v DMSO at 60°C for 2 h reached 64.6% substrate conversion and a specific productivity of 2.40 mmol h^-1 g^-1. Under these conditions, the process was performed reutilizing the catalyst for up to 18 cycles, maintaining >80% of the initial activity and a constant productivity 2.96 ± 0.42 µmol^-1 h^-1 g^-1. To the best of our knowledge, such productivity is the highest achieved for hesperetin production through an enzymatic approach.

The first total synthesis of acremomannolipin A, the potential Ca2+ signal modulator with a characteristic glycolipid structure, isolated from the filamentous fungus Acremonium strictum

The first total synthesis of acremomannolipin A, the potential Ca2+ signal modulator isolated from Acremonium strictum, was achieved by employing the characteristic stereoselective β-mannosylation of 4,6-O-benzylidene-protected mannosyl sulfoxide with a d-mannitol derivative in the presence of trifluoromethanesulfonic anhydride as the key reaction.

The first promoter for conditional gene expression in Acremonium chrysogenum: Iron starvation-inducible mir1P

The filamentous fungus Acremonium chrysogenum is of enormous biotechnological importance as it represents the natural producer of the beta-lactam antibiotic cephalosporin C. However, a limitation in genetic tools, e.g. promoters for conditional gene expression, impedes genetic engineering of this fungus. Here we demonstrate that in A. chrysogenum iron starvation induces the production of the extracellular siderophores dimerumic acid, coprogen B, 2-N-methylcoprogen B and dimethylcoprogen as well as expression of the putative siderophore transporter gene, mir1. Moreover, we show that the promoter of mir1, mir1P, is suitable for conditional expression of target genes in A. chrysogenum as shown by mir1P-driven and iron starvation-induced expression of genes encoding green fluorescence protein and phleomycin resistance. The obtained iron-starvation dependent phleomycin resistance indicates the potential use of this promoter for selection marker recycling. Together with easy scorable siderophore production, the co-regulation of mir1 expression and siderophore production facilitates the optimization of the inducing conditions of this expression system.

Acremomannolipin A, the potential calcium signal modulator with a characteristic glycolipid structure from the filamentous fungus Acremonium strictum

By the newly developed assay method, the glycolipid Acremomannolipin A (1) was isolated from a filamentous fungus Acremonium strictum as a potential calcium signal modulator. The structure of 1 elucidated on the basis of intensive spectroscopic analyses as well as its degradation studies is quite unique: the d-mannopyranose is connected to d-mannitol through a β-glycoside linkage; all the hydroxyls in the mannose are highly masked as peresters with aliphatic acids, and this moiety is made hydrophobic, whereas the mannitol part exhibits a highly hydrophilic property. The compound (1) showed the characteristic bioactivity property, enabling calcineurin deletion cells to grow in the presence of Cl−, which would be caused by calcium signal modulating. The activity was so potent as to exert the effect at a concentration of 200nM.

Screening and identification of cellulase producing yeast-like microorganisms from Brazilian biomes

The main goals of the present study included the screening and identification of cellulase producing wild yeasts, isolated from samples collected from different Brazilian biomes. They were selected according to their capabilities of degrading carboxymethyl cellulose (CMC) and micro-crystalline cellulose (SERVACEL ® ), as single carbon sources in solid medium. After the step of solid medium selection, yeast cells were grown in liquid medium containing cellulose (SERVACEL ® ); in shake flasks at temperature of 30°C and 150 rpm agitation for 288 h. Three specific activities were evaluated: endoglucanase (CMCase), total activity (filter paper activity), and cellobiase. From a total of 390 strains of wild yeasts previously isolated, 16 strains performed cellulose hydrolysis, verified by the colorless halo in the solid medium. Among these 16 strains, 5 stood out as presenting higher levels of enzyme activity. The following step, screening in liquid medium, indicated only one strain as a potential producer of cellulases, named as AAJ6, for which the highest hydrolytic activity on carboxymethyl cellulose (0.33 U/ml) and filter paper (0.039 U/ml) was recorded. Afterwards, this wild yeast strain (AAJ6) was molecularly identified by sequencing the ITS1-5.8S-ITS2 and D1/D2 domains of the subunit (26 S) ribosomal DNA. Sequencing resulted in the identification of this strain as yeast-like fungus Acremonium strictum . Keywords: Acremonium strictum , screening, identification, yeast-like, cellulases

Cyclohexadepsipeptides from the Filamentous Fungus Acremonium sp. BCC 2629

AbstractSeven new cyclohexadepsipeptides, beauvenniatins F, G1, G2, G3, H1, H2, and H3 (1–7, resp.), were isolated from cultures of the fungus Acremonium sp. BCC 2629. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations were addressed by HPLC analyses of their acid hydrolysates. Their biological activities were evaluated against Mycobacterium tuberculosis H37Ra and Plasmodium falciparum K1; the respective MIC and IC50 values were in the micromolar range.

Cyclic Heptapeptides, Cordyheptapeptides C–E, from the Marine-Derived Fungus Acremonium persicinum SCSIO 115 and Their Cytotoxic Activities

Three new cycloheptapeptides, cordyheptapeptides C-E (1-3), were isolated from the fermentation extract of the marine-derived fungus Acremonium persicinum SCSIO 115. Their planar structures were elucidated on the basis of extensive MS, as well as 1D and 2D (COSY, HMQC, and HMBC) NMR spectroscopic data analyses. The absolute configurations of the amino acid residues were determined by single-crystal X-ray diffraction, Marfey's method, and chiral-phase HPLC analysis. Compounds 1 and 3 displayed cytotoxicity against SF-268, MCF-7, and NCI-H460 tumor cell lines with IC(50) values ranging from 2.5 to 12.1 μM.

Phthalide and Isocoumarin Derivatives Produced by an Acremonium sp. Isolated from a Mangrove Rhizophora apiculata

Nine new fungal metabolites, one phthalide derivative, acremonide (1), and eight isocoumarin derivatives, acremonones A-H (2-9), were isolated from the mangrove-derived fungus Acremonium sp. PSU-MA70 together with 10 known compounds. Their structures were determined by NMR analysis. The known 8-deoxytrichothecin and trichodermol exhibited moderate antifungal activity against Candida albicans and Cryptococcus neoformanns, respectively.

Acremolin, a new 1H-azirine metabolite from the marine-derived fungus Acremonium strictum

Acremolin (1), a novel modified base, was isolated from the culture broth of the marine fungus Acremonium strictum. Based on combined spectroscopic analyses, the structure of this compound was that of a methyl guanine base containing an isoprene unit. In addition, the presence of a 1H-azirine moiety is unprecedented among natural products. This compound exhibited weak cytotoxicity against an A549 cell line.

Microscopic Fungi on Fresh Meat Derived from Roe Deer (Capreolus Capreolus) and Red Deer (Cervus Elaphus)

Biežāk sastopamās mikroskopiskās sēnes stirnu(Capreolus capreolus)un staltbriežu(Cervus elaphus)gaļā

Cyclohexadepsipeptides from Acremonium sp. BCC 28424

Six new cyclohexadepsipeptides, beauvenniatins A–E ( 1– 5), and beauvericin J ( 6), together with the known beauvericin ( 7) and enniatin B ( 8), were isolated from the fungus Acremonium sp. BCC 28424. The productions of minor derivatives 3– 6, possessing an N-methyl- l-tyrosine, were enhanced by feeding l-tyrosine in the liquid fermentation medium. Antimalarial, antitubercular, and cytotoxic activities of these cyclodepsipeptides were evaluated.

Persistierende kontaktlinsenassoziierte Keratitis

A 43-year-old woman presented with a 2-month history of contact lens-associated keratitis and corneal ulceration on the left eye. Without having isolated the pathogenic agent, a calculated anti-infective and anti-inflammatory therapy had already been administered with no signs of improvement. Filamentous fungi (Acremonium sp) were found in the scraping material and the contact lens solution. A keratoplasty à chaud was necessary despite immediate initiation of pathogen-specific therapy. Early identification of the pathogen via corneal debridement and culturing are standard procedures in order to initiate a specific therapy and prevent ulceration which can threaten the visual outcome.