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At least 19 recordsLinked to original sources

Rapid identification of Acremonium lolii and Acremonium coenophialum endophytes through arbitrarily primed PCR.

Using a random decamer 5'-CCGAGGTGAC-3' in an arbitrarily primed PCR, similar band patterns were observed between Acremonium lolii and A. coenophialum DNA, which were somewhat different from those formed by other fungal DNA. Despite sharing bands of around 0.7, 0.9 and 2.1 kb, A. lolii can be distinguished from A. coenophialum by the presence of an additional band at around 0.5 kb in the arbitrarily primed PCR.

Acremonium↗

[Correlation of cephalosporin C synthesis and proteolytic enzymes in a differentiating culture of Acremonium chrysogenum (Cephalosporum acremonium) mutants].

The effect of the growth conditions and composition of the nutrient medium on the synthesis of cephalosporin C, alkaline exoproteases and cell differentiation was studied in various strains of Acremonium chrysogenum. It was observed that the changes in the above processes occurred simultaneously and depended on the aeration rate, temperature, illumination level and concentrations of methionine and soybean meal. Close correlation between the synthesis of alkaline exoproteases, cephalosporin C and formation of secondary structures in the strains of A. chrysogenum was shown.

Acremonium↗

Efficient integrative transformation of Cephalosporium acremonium.

A hybrid gene, IPNSp/HPTorf, was constructed by placing an 850 bp sequence of Cephalosporium acremonium DNA next to the 5' end of a bacterial open reading frame, HPTorf. The sequence was obtained as an 850 bp NcoI restriction fragment from the 5' non-coding region of the C. acremonium isopenicillin N synthetase (IPNS) gene. The HPTorf was obtained from a bacterial gene that coded for a hygromycin B phosphotransferase (HPT). Plasmids that contained IPNSp/HPTorf transformed C. acremonium to a stably maintained hygromycin B resistant phenotype. Southern analysis of total DNA from transformants demonstrated multiple integrations of the transforming DNA in the high molecular weight DNA of most transformants, but single integrations were observed in a few transformants. The number of transformants per microgram of DNA was about 100 times greater than for plasmids that contained the HPTorf without any juxtaposed eucaryotic promoter sequence. Plasmids with the promoterless HPTorf and plasmids with a truncated S. cerevisiae phosphoglycerate kinase promoter juxtaposed to the HPTorf transformed C. acremonium at equivalent low frequencies. Transformation of C. acremonium with linearized plasmid DNA produced at least 2-3 fold more transformants than the corresponding circular molecule. Several observations were made concerning protoplast formation and handling which made the transformation procedure more efficient and allowed a greater proportion of protoplasts to regenerate to viable walled cells. Plasmids were constructed that contained both the IPNSp/HPTorf and additional elements: fragments of C. acremonium ribosomal DNA (rDNA), or a fragment of C. acremonium mitochondrial DNA possessing activity as an autonomous replication sequence (ARS) in S. cerevisiae, or putative transcriptional termination/polyadenylation signals from the IPNS gene. These plasmids transformed C. acremonium at frequencies experimentally equivalent to those containing IPNSp/HPTorf without any of these additional elements.

Acremonium↗

Expression of the penDE gene of Penicillium chrysogenum encoding isopenicillin N acyltransferase in Cephalosporium acremonium: production of benzylpenicillin by the transformants.

No DNA sequence homologous to the penDE gene of Penicillium chrysogenum was found in the genome of three different strains of Cephalosporium acremonium. The pcbC-penDE gene cluster of P. chrysogenum complemented the isopenicillin N synthase deficiency of C. acremonium mutant N2 and resulted in the production of penicillin, in addition to cephalosporin, in cultures supplemented with phenylacetic acid. The penicillin formed was identified as benzylpenicillin by HPLC and NMR studies. The penDE gene of P. chrysogenum is expressed in C. acremonium forming a transcript of 1.15 kb. The transcript is processed and translated in C. acremonium resulting in the formation of acyl CoA: isopenicillin N acyl transferase. When the penDE gene was introduced into a cephalosporin producing strain, the total titre of beta-lactam antibiotics comprised distinct proportions of penicillin and cephalosporin in different transformants. Analysis of the hybridization patterns of the DNA of C. acremonium transformed with the pcbC or penDE genes indicated that integration occurs by non-homologous recombination.

Acremonium↗

[Antifungal susceptibility of Acremonium species using E-test and Sensititre].

Filamentous fungi have become a common cause of severe infections, especially in immunocompromised patients. In recent years, the number and diversity of the infections caused by Acremonium species have increased and numerous species have been implicated. As is the case for most emerging pathogens, the optimal therapeutic approach to Acremonium species remains to be determined. We used two methods to determine the in vitro susceptibility to amphotericin B, itraconazole and fluconazole for 15 clinical isolates of eight different species of Acremonium. The MICs were determined according to protocol M38-A of the National Committee for Clinical Laboratory Standards (NCCLS) document, using the Sensititre and E-test microdilution methods. Amphotericin B was effective in vitro for few species using the Sensititre method. However, high MICs were obtained with E-test. Fluconazole and itraconazole were ineffective according to both methods. Acremonium species are generally resistant to the most commonly used antifungal agents. Consequently, Acremonium susceptibility testing is recommended to assist in choosing adequate treatment of infections caused by this filamentous fungus.

Acremonium↗

Relationships among non-Acremonium sp. fungal endophytes in five grass species.

Many cool-season grasses (subfamily Pooideae) possess maternally transmitted fungal symbionts which cause no known pathology and often enhance the ecological fitness and biochemical capabilities of the grass hosts. The most commonly described endophytes are the Acremonium section Albo-lanosa spp. (Acremonium endophytes), which are conidial anamorphs (strictly asexual forms) of Epichloë typhina. Other endophytes which have been noted are a Gliocladium-like fungus in perennial ryegrass (Lolium perenne L.) and a Phialophora-like fungus in tall fescue (Festuca arundinacea Schreb.). Here, we report the identification of additional non-Acremonium sp. endophytes (herein designated p-endophytes) in three more grass species: Festuca gigantea, Festuca arizonica, and Festuca pratensis. In each grass species, the p-endophyte was cosymbiotic with an Acremonium endophyte. Serological analysis and sequence determinations of variable portions of their rRNA genes indicated that the two previously identified non-Acremonium endophytes are closely related to each other and to the newly identified p-endophytes. Therefore, the p-endophytes represent a second group of widely distributed grass symbionts.

Base Sequence↗

Homologous transformation of Cephalosporium acremonium with the nitrate reductase-encoding gene (niaD).

We report the development of a homologous transformation system for Cephalosporium acremonium using the niaD gene of the nitrate assimilation (NA) pathway. Mutants in the NA pathway were selected on the basis of chlorate resistance by conventional means. Screening procedures were developed to differentiate between nitrate reductase apoprotein structural gene mutants (niaD) and molybdenum cofactor gene mutants (cnx) as wt C. acremonium, unlike most filamentous fungi, fails to grow on minimal medium with hypoxanthine as a sole source of nitrogen. Phage clones carrying the niaD gene were isolated from a C. acremonium library constructed in lambda EMBL3 using the A. nidulans niaD gene as a heterologous probe. An 8.6-kb EcoRI fragment was subcloned into pUC18, and designated pSTA700. pSTA700 was able to transform stable niaD mutants to NA at a frequency of up to 40 transformants per microgram DNA. Transformants were easily visible since the background growth was low and no abortives were observed. Gene replacements, single copy homologous integration and complex multiple integrations were observed. The niaD system was used to introduce unselected markers for hygromycin B resistance and benomyl resistance into C. acremonium by cotransformation.

Acremonium↗

Infection due to the fungus Acremonium (cephalosporium).

Human infections due to fungi belonging to the genus Acremonium occur uncommonly, but unlike infections due to other filamentous fungi, usually affect immunocompetent individuals. Mycetoma, which usually develops following trauma, is the most common infection caused by Acremonium spp. Other sites of infection include the eye (generally following abrogation of ocular defenses), colonizing disease of the lung and gastrointestinal tract, as well as locally invasive infections such as osteomyelitis, sinusitis, arthritis, and peritonitis. Pneumonia and disseminated infections including meningitis, endocarditis, and cerebritis rarely have been reported. Optimal treatment of acremonium infections is not well defined both because infections due to these organisms are rare, and because many reports antedate effective antifungal therapy. In addition, susceptibility testing of filamentous fungi is poorly standardized, and in vitro sensitivity may not correlate with clinical response. Based on anecdotal reports, treatment of most invasive acremonium infections requires a combination of surgical intervention, when possible, and a regimen of amphotericin B. Some azoles also display inhibitory activity. Until more details are available regarding susceptibility of these organisms to antifungal agents, amphotericin B is recommended as initial therapy with the addition of either ketoconazole or fluconazole in infections of a life-threatening nature.

Acremonium↗

Morphology and kinetics studies on cephalosporin C production by Cephalosporium acremonium M25 in a 30-l bioreactor using a mixture of inocula.

AIMS: In this study, the relationship between morphology and cephalosporin C (CPC) production in a 30-l bioreactor culture of Cephalosporium acremonium M25 using a 3:7 seed mixture was investigated. In addition, the kinetic model was established and applied. METHODS AND RESULTS: CPC production was performed in a 30-l bioreactor using a 3:7 seed mixture. It was recognized that a 3:7 seed mixture was able to reduce lag phase and enhance CPC production. The maximum CPC production and cell mass were 1.96 and 81.5 g l-1 respectively. Through a morphology study by observation using image analysis, it was concluded that changes of morphological features predicted the progressive production of CPC and that a morphology study could be useful in monitoring the CPC fermentation by C. acremonium M25. In the kinetics study, a kinetic model of CPC fermentation was developed and applied. The proposed model could adequately describe the fermentation of C. acremonium M25 in a 30-l bioreactor. CONCLUSIONS: CPC productivity was improved by using a 3:7 seed mixture in a 30-1 bioreactor. The changes in morphological features showed a very similar tendency with CPC production. A kinetic model of CPC fermentation was successfully established. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the present study suggest that the use of a 3:7 seed mixture inocula has considerable possibilities for improving CPC productivity if applied to industrial scale fermentations. Through morphology and kinetics study, the kinetic model to describe the morphological differentiation and CPC production by C. acremonium M25 was established.

Acremonium↗

The cefG gene of Cephalosporium acremonium is linked to the cefEF gene and encodes a deacetylcephalosporin C acetyltransferase closely related to homoserine O-acetyltransferase.

The gene (cefG) encoding the acetyl coenzyme A:deacetylcephalosporin C acetyltransferase of Cephalosporium acremonium (synonym Acremonium chrysogenum) C10 has been cloned. It contains two introns and encodes a protein of 444 amino acids with an M(r) of 49,269 that correlates well with the M(r) deduced by gel filtration. The cefG gene is linked to the cefEF gene (encoding the bifunctional deacetoxycephalosporin C synthase/hydroxylase), but it is expressed in an orientation opposite that of the cefEF gene. Two transcripts of 1.2 and 1.4 kb were found in C. acremonium that correspond to the cefEF and cefG genes, respectively; the degree of expression of the cefG gene was clearly lower than that of the cefEF gene in 48-h cultures. The cloned cefG complemented the deficiency of deacetylcephalosporin acetyltransferase in the nonproducer mutant C. acremonium ATCC 20371 and restored cephalosporin biosynthesis in this strain. Heterologous expression of the cefG genes took place in Penicillium chrysogenum. The deacetylcephalosporin acetyltransferase showed a much higher degree of homology with the O-acetylhomoserine acetyltransferases of Saccharomyces cerevisiae and Ascobolus immersus than with other O-acetyltransferases. The cefEF-cefG cluster of genes encodes the enzymes that carry out the three late steps of the cephalosporin biosynthetic pathway and is not linked to the pcbAB-pcbC gene cluster that encodes the first two steps of the pathway.

Acetyltransferases↗

Genetic diversity among clinical isolates of Acremonium strictum determined during an investigation of a fatal mycosis.

Primarily saprophytic in nature, fungi of the genus Acremonium are a well-documented cause of mycetoma and other focal diseases. More recently, a number of Acremonium spp. have been implicated in invasive infections in the setting of severe immunosuppression. During the course of routine microbiological studies involving a case of fatal mycosis in a nonmyeloablative hematopoietic stem cell transplant patient, we identified a greater-than-expected variation among strains previously identified as Acremonium strictum by clinical microbiologists. Using DNA sequence analysis of the ribosomal DNA intergenic transcribed spacer (ITS) regions and the D1-D2 variable domain of the 28S ribosomal DNA gene (28S), the case isolate and four other clinical isolates phenotypically identified as A. strictum were found to have <99% homology to the A. strictum type strain, CBS 346.70, at the ITS and 28S loci, while a sixth isolate phenotypically identified only as Acremonium sp. had >99% homology to the type strain at both loci. These results suggest that five out of the six clinical isolates belong to species other than A. strictum or that the A. strictum taxon is genetically diverse. Based upon these sequence data, the clinical isolates were placed into three genogroups.

Acremonium↗

A protective endophyte of maize: Acremonium zeae antibiotics inhibitory to Aspergillus flavus and Fusarium verticillioides.

The maize endophyte Acremonium zeae is antagonistic to kernel rotting and mycotoxin producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for antagonism, and interferes with A. flavus infection and aflatoxin contamination of preharvest maize kernels. Chemical studies of an organic extract from maize kernel fermentations of Acremonium zeae (NRRL 13540), which displayed significant antifungal activity against Aspergillus flavus and F. verticillioides, revealed that the metabolites accounting for this activity were two newly reported antibiotics pyrrocidines A and B. Pyrrocidines were detected in fermentation extracts for 12 NRRL cultures of Acremonium zeae isolated from maize kernels harvested in Illinois (4/4 cultures), North Carolina (5/5), Georgia (1/2) and unrecorded locations within the USA (2/2). Pyrrocidine B was detected by LCMSMS in whole symptomatic maize kernels removed at harvest from ears of a commercial hybrid that were wound-inoculated in the milk stage with A. zeae (NRRL 13540) or (NRRL 13541). The pyrrocidines were first reported from the fermentation broth of an unidentified filamentous fungus LL-Cyan426, isolated from a mixed Douglas Fir hardwood forest on Crane Island Preserve, Washington, in 1993. Pyrrocidine A exhibited potent activity against most Gram-positive bacteria, including drug-resistant strains, and was also active against the yeast Candida albicans. In an evaluation of cultural antagonism between 13 isolates of A. zeae in pairings with A. flavus (NRRL 6541) and F. verticillioides (NRRL 25457), A. zeae (NRRL 6415) and (NRRL 34556) produced the strongest reaction, inhibiting both organisms at a distance while continuing to grow through the resulting clear zone at an unchanged rate. Maximum colony diameters for A. zeae (NRRL 6415) and (NRRL 13540), on potato dextrose agar after 14 d, were attained within the range of 25-30 degrees C, with less growth recorded at 15 degrees and 37.5 degrees and no growth at 5 degrees. Potential interactions between A. zeae and other maize endophytes are considered and the significance of these interactions relative to the aflatoxin and fumonisin contamination of preharvest maize is presented. This is the first report of natural products from Acremonium zeae.

Acremonium↗

Acremonium pyomyositis in a pediatric patient with acute leukemia.

Invasive Acremonium infection in humans is rare. We report a patient with leukemia who developed pyomyositis due to Acremonium species. Painful cutaneous nodules and severe myalgia were the first clinical manifestations during the neutropenic stage after chemotherapy. Magnetic resonance image (MRI) revealed multiple nodular lesions scattered along the intramuscular regions of the lower legs. Culture of an aspiration grew Acremonium species. Surgical drainage was performed. Although all antifungal agents tested showed no in vitro inhibitory activity, we successfully treated this patient with amphotericin B, granulocyte colony-stimulating factor (G-CSF), and surgical drainage.

Acremonium↗

Lethal double infection with Acremonium strictum and Aspergillus fumigatus during induction chemotherapy in a child with ALL.

Fungal infections are a major cause of morbidity and mortality in patients during chemotherapeutic treatments and malignant hematologic disease. We present a case of a double fungal infection with disseminated Acremonium strictum (A. strictum) and pulmonary Aspergillus fumigatus (A. fumigatus) and its rapid clinical course. A 17-year-old boy with prolonged neutropenia developed a disseminated fungal infection during induction chemotherapy of his acute lymphoblastic leukemia. The infection was rapidly lethal despite neutrophil recovery and early antifungal combination therapy with amphotericin B and caspofungin. Since there are only a few reports about invasive Acremonium infections, we present this case with regard to differences in the clinic pathologic features of Aspergillosis and other opportunistic fungal infections due to Fusarium or Acremonium species.

Acremonium↗

Cloning of the pyr4 gene encoding orotidine-5'-phosphate decarboxylase in Cephalosporium acremonium.

We have cloned the Cephalosporium acremonium pyr4 gene by cross-hybridization with the equivalent gene from Neurospora crassa, the closest relative from which this gene is available. The C. acremonium pyr4 gene complements an E. coli pyrF mutant lacking orotidine-5'-phosphate decarboxylase (OMPdecase), and most probably does not contain introns. Maxicell analysis in E. coli shows that it encodes a 46 kDa polypeptide. The C. acremonium OMPdecase contains a highly conserved pentadecapeptide characteristic for this category of enzyme. Extensive sequence comparison suggests an important role of this region in enzymatic activity.

Acremonium↗

Acremonium strictum fungaemia in a paediatric patient with acute leukaemia.

A 7-y-old boy with relapsed acute lymphatic leukaemia developed fungaemia due to Acremonium strictum, a fungus belonging to the group of the hyaline hyphomycetes. Initially, the fungus was misdiagnosed as Candida sp. due to the presence of abundant adventitious forms. At the time of diagnosis the patient was neutropenic and had a central venous catheter (CVC) in situ. The formation of an occlusive thrombotic mass in the v. subclavia dextra complicated the infection. Treatment consisted of amphotericin B, fluconazole, granulocyte colony-stimulating factor (G-CSF) and removal of the CVC. However the patient responded clinically only after the intravascular thrombus had been removed surgically. Amphotericin B, voriconazole and terbinafine showed high activity in vitro against the Acremonium isolate. A literature review revealed 5 other immunocompromised paediatric patients with a systemic or localized infection due to Acremonium spp.

Acremonium↗

Acremonium species: new emerging fungal opportunists--in vitro antifungal susceptibilities and review.

We provide an overview of opportunistic fungal infections caused by Acremonium (Cephalosporium) species and discuss the classification of these species as well as the diagnosis and treatment of acremonium infections. We used a microdilution broth method to compare in vitro susceptibilities and minimum inhibitory concentrations and minimum fungicidal concentrations of amphotericin B, miconazole, itraconazole, 5-fluorocytosine, fluconazole, and ketoconazole for 33 clinical and environmental isolates of Acremonium. In general, the isolates tested displayed little susceptibility to the antifungals tested. Fluconazole and 5-fluorocytosine were ineffective in all cases. The efficacy of the remaining drugs was dependent on the strain. Amphotericin B showed the best results.

Acremonium↗

Morphologic criteria for the preliminary identification of Fusarium, Paecilomyces, and Acremonium species by histopathology.

Nontraditional human pathogenic fungi, including Fusarium, Paecilomyces, and Acremonium species, have been increasingly documented as agents of infection in immunocompromised patients and, occasionally, in normal hosts. Although definitive identification of these fungi requires culture, they often can be identified provisionally in tissue sections by a combination of histologic features, including hyaline septate hyphae and characteristic reproductive structures known as phialides and phialoconidia. These morphologic characteristics, although familiar to mycologists, are easily overlooked by histopathologists; as a result, Fusarium species and Paecilomyces lilacinus are frequently misidentified in tissue sections as Aspergillus or Candida species. We identified 19 culture-proved cases of infection with species of Fusarium, Paecilomyces, or Acremonium; retrospectively reviewed histologic specimens stained by routine hematoxylin and eosin, Gomori methenamine silver, and/or periodic acid-Schiff stains; and delineated morphologic criteria that will help pathologists make a preliminary identification of these fungi by histopathology. Adventitious sporulation was found in 9 of 9 infections caused by Paecilomyces species, 7 of 10 infections caused by Fusarium species, and in the single case of infection caused by Acremonium strictum. Histologic recognition of these morphologies may help clinicians select appropriate initial antifungal treatment and manage the infection.

Acremonium↗