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PubMed1992

Isolation of deacetoxycephalosporin C from fermentation broths of Penicillium chrysogenum transformants: construction of a new fungal biosynthetic pathway.

Deacetoxycephalosporin C (DAOC), a precursor of cephalosporins excreted by Cephalosporium and Streptomyces species, has been produced in Penicillium chrysogenum transformed with DNA containing a hybrid penicillin N expandase gene (cefEh) and a hybrid isopenicillin N epimerase gene (cefDh). DAOC from a P. chrysogenum transformant was identified by ultraviolet light (UV), high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and mass spectrum analyses. P. chrysogenum transformed with DNA containing cefEh without cefDh did not produce DAOC. Untransformed P. chrysogenum produced penicillin V (phenoxymethylpenicillin) but not DAOC. Transformants also produced penicillin V but, in general, less than untransformed P. chrysogenum. The cefEh and cefDh genes were constructed by replacing the open reading frame (ORF) of cloned P. chrysogenum pcbC and penDE genes with the ORF of the Streptomyces clavuligerus expandase gene, cefE, and the ORF of the Streptomyces lipmanii epimerase gene, cefD, respectively. Analyses of representative transformants suggested that production of DAOC occurred via cefEh and cefDh genes stably integrated in the P. chrysogenum genome. DNA from untransformed P. chrysogenum did not hybridize to cefE or cefD gene probes.

Amino Acid Isomerases↗

PubMed2003

Fatal disseminated Acremonium strictum infection in a preterm newborn: a very rare cause of neonatal septicaemia.

Species of the genus Acremonium (Cephalosporium) are opportunistic micro-organisms that are environmentally widespread saprophytes in soil and can, very rarely, be pathogenic in humans. Disseminated infection has been described in patients with immunodeficiency, but has previously been reported in only one neonate. A preterm infant with Acremonium strictum fungaemia is reported here. The patient was born at 27 weeks gestation and weighed 870 g at birth. She needed intensive respiratory management and became septic on day 11 of life. Blood and cerebrospinal fluid (CSF) cultures were positive for A. strictum. The patient did not respond to therapy with amphotericin B plus fluconazole and died on day 25 of life. The autopsy showed foci due to A. strictum in the brain, liver and heart.

Acremonium↗

PubMed1981

Effect of treatment of soil with keratinaceous material on soil fungi.

In the early periods of soil storage, the total number of fungi almost regularly and significantly increased with the concentration of keratinaceous material (ground buffalo hooves) between 1% and 10%. A concentration of 20% was stimulative after 7 days and became toxic after 15 days and remained so through the end of the experiment. With increase in the storage period, the beneficial effect of all concentrations was lost and in the case of high concentrations (5-20%) toxic ammonia was produced. The occurrence of Scopulariopsis brevicaulis, Cephalosporium acremonium, Chrysosporium tropicum, C. indicum, and C. keratinophilum increased markedly, especially at the higher concentrations of the keratinaceous material and after long periods of incubation. With increase in the concentration of keratinaceous material, the rate of evolution of ammonia from the soil sharply increased during the second week after treatment and fell off sharply during the third and fourth weeks. In soil stored at 35 C, the rate of decline in total fungi after longer periods of incubation was sharper at 35 C than at 25 C. Also the amount of evolved ammonia during the first and the second weeks was almost always higher at 35 C than at 25 C. Fourteen species were tested for keratinolytic activity. Three of them were highly keratinolytic and five moderately so.

Animals↗

PubMed1988

The major aeroallergens in Guangxi, China.

Over a 2-year period we have identified pollen grains from 48 families of grasses, as well as mould spores and mite particles during air sampling in Guangxi Province. The major aeroallergens were Artemisia, Moraceae and Euophoribiacea, and the spores of Aspergillus, Penicillinum, Cephalosporium and Helminthosporium. Mites were probably also one of the major outdoor aeroallergens. Our investigations also included inspection of the vegetation of the geographical area involved, as well as skin testing on 774 subjects using extracts of 37 aeroallergens. We believe that this work has provided fundamental information on seasonal allergy in Southern China and South-east Asia.

Air Pollution↗

PubMed1989

Studies on mycotic keratitis.

One hundred and fifty cases of corneal ulcers from the Government Ophthalmic Hospital, Madras, were investigated during 1980-1982 for the mycoflora. 68 cases (45%) were positive for fungi, comprising species of Aspergillus (36 cases), Penicillium, Fusarium (8 cases each), Curvularia (4 cases), Candida albicans and Mucor (3 cases each), Drechslera (2 cases) and Cladosporium, Cephalosporium, Pullularia, and Allescheria boydii (1 case each). Incidence of these fungi in mycotic keratitis is correlated with factors such as age, sex and occupation of the patients and is discussed in detail.

Adult↗

PubMed1999

Glutamine-230 influences enzyme solubility but not catalysis in Streptomyces clavuligerus isopenicillin N synthase.

The conversion of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N is dependent upon the catalytic action of isopenicillin N synthase (IPNS), an important enzyme in the penicillin and cephalosporin biosynthetic pathway. Recent catalytic investigations on the conserved glutamine-230 in the bacterial Streptomyces jumonjinensis IPNS and the corresponding glutamine-234 in the fungal Cephalosporium acremonium IPNS showed contrasting results whereby the former was suggested to be essential for IPNS activity whereas the latter was found not to be so. In order to unravel these conflicting results, we report the site-directed mutagenesis investigation on the corresponding glutamine-230 in a third IPNS isozyme, which is the bacterial Streptomyces clavuligerus IPNS (scIPNS). IPNS enzymatic assays showed that catalytic activity of the mutant Q230L scIPNS was reduced but not eliminated. Moreover, the solubility of the mutant enzyme was also markedly reduced. Hence, we can conclude that glutamine-230 in scIPNS is not essential for catalysis and correspondingly in all IPNS.

Catalysis↗

PubMed1977

Microbial aggregate contamination of water lines in dental equipment and its control.

Water from some dental clinics has been examined and found to be discoloured, badly tasting and with a foul odour. Moreover, brown or black flakes were often present in tap water, as well as in the water lines of dental equipment. Examination by phase-contrast and electron microscope showed the flakes to consist of aggregated fungi and bacteria, and similar structures were found in a layer on the inner surfaces of the clinics water tubes and pipes. The ultrastructure of some aggregating microorganisms, including fungal hyphae and sheath-forming and stalked bacteria, was studied in detail, and several modes of aggregation were suggested. Cultivation of contaminated water samples revealed the presence of filamentous fungi, including Cladosporium and Cephalosporium, and of non-fluorescent Pseudomonas, Aeromonas, Acinetobacter, Alcaligenes, Flavobacterium, and Moraxella (?). Removal of microorganisms from the walls of the tubing was effectively accomplished by rinsing with the non-corrosive solution of 4 per cent Tween 80, coloured with Ponceau 4 R.

Bacteria↗

PubMed1994

Improved expression of a hybrid Streptomyces clavuligerus cefE gene in Penicillium chrysogenum.

A hybrid cefE gene, encoding penicillin N expandase, was constructed by fusing the promoter sequences, Pcp, and terminator sequences, Pct from the Penicillium chrysogenum pcbC gene to the open reading frame (orf), cefEorf, from the Streptomyces clavuligerus cefE gene. The resulting hybrid gene, Pcp/cefE'orf/Pct, differed from a previously reported hybrid cefE gene contained on plasmid pPS65. The latter gene, Pcp/cefE'orf/Sct, contained the Pcp sequences fused to the S. clavuligerus cefE orf still attached to the S. clavuligerus terminator sequences, Sct. The new hybrid gene was transformed into P. chrysogenum on plasmid vector pRH6. Transformants were selected by phleomycin resistance conferred by a hybrid ble gene present on plasmid pRH6. The hybrid ble gene was formed by attaching Pcp sequences to the ble orf. Among transformants obtained with pRH6, one exhibited a 70-fold higher level of activity of penicillin N expandase than the best transformant previously obtained from a 10-fold larger population of pPS65 transformants. The penicillin N expandase activity in pRH6 transformant, 9EN-5-1, was fourfold higher than the activity in the S. clavuligerus strain used as the source of the cefE orf and 75% of the activity observed in an industrial strain of Cephalosporium acremonium. Sequencing of the junctions of the heterologous DNA in Pcp/cefEorf/Pct uncovered a modification of the cefE open reading frame introduced during construction of the hybrid gene; the modified open reading frame is designated cefE'orf.

Base Sequence↗

PubMed1990

Pathogenic fungi in soils of Jabalpur, India.

Results of a preliminary survey of pathogenic fungi in soils collected from forest, riverside and residential garbage soil in Jabalpur, India, are reported. A total of 45 soils samples were examined, of which 39 (87%) were positive for fungi, 66 species of fungi classified in 35 genera were isolated: Chrysosporium (78%), Fusarium (69%), Aspergillus (47%), Microsporum (38%), Gliocladium (16%), Acremonium (11%), Penicillium (11%), Humicola (9%), Scopulariopsis (7%), Paecilomyces (7%), Cladosporium (7%); Chaetomium, Colletotrichum, Cunninghamella, Microascus and Rhizopus (4% each); Absidia, Aphanocladium, Arthrobotrys, Botryotrichum, Candida, Cephaliophora, Cephalosporium, Curvularia, Histoplasma, Mucor, Shanorella, Syncephalastrum, Thermomyces, Trichophyton, Trichothecium and Verticillium (2% each); mycelia sterilia (6%). Acremonium persicinum, Cladosporium trichoides and Shanorella spirotricha are new to India. A new species of Humicola has also been isolated.

Fungi↗

PubMed1984

Enzymatic approach to syntheses of unnatural beta-lactams.

Four enzymes associated with the transformation of the peptide delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV) into the beta-lactam antibiotic desacetylcephalosporin C have been isolated from the prokaryotic organism Streptomyces clavuligerus and immobilized. Appropriate choice of the cofactors allows continuous and quantitative conversion of the peptide into either penicillins or cephalosporins at room temperature. The overall process includes four oxidations, two ring closures, and one epimerization. In contrast, cell-free transformations with the eukaryotic organism Cephalosporium acremonium do not proceed beyond the oxidation level of penicillin. The amino acids of the natural peptide ACV can be altered by chemical means; several of the resulting peptides are converted into novel antibiotics by the enzymes of Streptomyces clavuligerus.

Anti-Bacterial Agents↗

PubMed1984

A pure enzyme catalyzing penicillin biosynthesis.

Isopenicillin N synthetase (cyclase) has been purified to homogeneity from Cephalosporium acremonium strain C-10. The enzyme has a molecular weight of 40,000 to 42,000 and yields a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was purified in 10 percent yield by a combination of protamine sulfate and ammonium sulfate precipitations, gel filtration, and ion-exchange high-performance liquid chromatography. The purified enzyme can be stabilized with sucrose and stored at -20 degrees C for several weeks without any loss in activity.

Acremonium↗

PubMed1972

Detection of a cephalosporin C acetyl esterase in the carbamate cephalosporin antibiotic-producing culture, Streptomyces clavuligerus.

The possible role of a cephalosporin C acetyl esterase in the formation of the beta-lactam antibiotic A16886A, 7-(5-amino-5-carboxyvaleramido)-3-carbamoyloxy-methyl-3-cephem-4-carboxylic acid, by Streptomyces clavuligerus was studied. Addition of dl-valine-(14)C-1 to a fermentation of Cephalosporium acremonium gave cephalosporin C-(14)C-9 (I). The formation of deacetylcephalosporin C-(14)C-9 from I occurred at a greater rate in broths of S. clavuligerus than in the broths of C. acremonium, or in the autoclaved broths of S. clavuligerus. Diisopropylfluorophosphate partially inhibited the deacetylation of I in S. clavuligerus broth. An intracellular cephalosporin C esterase in S. clavuligerus could not be demonstrated. Although A16886A has been chemically synthesized from deacetylcephalosporin C, this reaction could not be demonstrated with S. clavuligerus.

Acetylesterase↗

PubMed1972

Incorporation of labeled precursors into A16886B, a novel -lactam antibiotic produced by Streptomyces clavuligerus.

The incorporation of C-14 from amino acids into A16886B, 7-(5-amino-5-carboxyvaleramido)-7-methoxy-3-carbamoyloxymethyl-3-cephem-4- carboxylic acid, by Streptomyces clavuligerus is reported. As with cephalosporin C biosynthesis by the mold Cephalosporium acremonium, labels from cysteine, valine, and alpha-amino-adipic acid were incorporated. Unlike cephalosporin C, in A16886B label from lysine was incorporated into the alpha-aminoadipic acid side chain. Label from methionine-(14)C-methyl was incorporated into the methoxyl group. The relative percentage of incorporation of (3)H and (14)C from doubly labeled cystine suggests the improbability of the C-7 methoxyl group arising from an intermediate containing a double bond between C-6 and C-7.

Amides↗

PubMed1978

Development of the agar disk method for the rapid selection of cephalosporin producers with improved yields.

To screen the abilities of mutant strains of Cephalosporium to produce cephalosporin C, colonies of the organism were grown on the surface of small (4-mm diameter) disks of agar medium. After incubation of the disks for periods of up to 5 days, the antibiotic contents of the disks were assayed by placing them on agar plates of the assay organism and determining the diameters of the inhibition zones. The amount of nitrogen source in the agar disk medium was used to control the amount of antibiotic produced in the disk and, thus, the sensitivity of screening. The relation of agar disk inhibition zone diameters to log shake-flask titers was linear with short incubation times (2 to 3 days) of the disks, but shifted towards a higher order with prolonged incubation (4 to 5 days). The optimum incubation time for the disks was 4 to 5 days, and then a 15% difference in zone diameters was significant with 10 disks per sample. The minimum difference between the shake-flask titers, which could be detected by the agar disk method with 10 disks per sample, was about 30% with 5 days of incubation for the disks. The results suggest that the shake-flask culture underestimated the degree of improvement in strain productivity.

Acremonium↗

PubMed1979

Isolation and nature of intracellular alpha-aminoadipic acid-containing peptides from Paecilomyces persicinus P-10.

Small intracellular peptides containing alpha-aminoadipic acid, cysteine, and a valine moiety were obtained from mycelia of Paecilomyces persicinus P-10 by ethanol or trichloroacetic acid extraction. After performic acid oxidation and ion-exchange chromatography, analysis of the peptide fractions by two-dimensional thin-layer electrophoresis and chromatography revealed the presence of three related peptides, as sulfonic acid derivatives, each containing alpha-aminoadipic acid. Each peptide was isolated in chromatographically pure form by semipreparative thin-layer electrophoresis and chromatography. The purified peptides were subjected to differential hydrolysis, dansylation, and combined dansylation-phenylisothiocyanate sequence analysis. Based on these studies, the structures of the isolated peptides were determined to be (i) glycl-delta-(alpha-aminoadipyl)-cysteinyl-beta-hydroxyvaline, (ii) glycyl-delta-(alpha-aminoadipyl)-cysteinylvaline, and (iii) delta-(alpha-aminoadipyl)-cysteinylvaline. The peptides isolated from Paecilomyces are similar to the alpha-aminoadipic acid-cysteine-valine moiety complex peptides isolated from Cephalosporium.

2-Aminoadipic Acid↗

PubMed1980

Cell-free cyclization of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N.

Cell-free cyclization of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to isopenicillin N by lytic enzyme extracts of Cephalosporium acremonium M-0198 was stimulated by ferrous ions. The optimum concentration of FeSO4 was 80 microM. No additional stimulation was observed with ascorbate, adenosine 5'-triphosphate, or alpha-ketoglutarate, but Triton X-100 and sonication of the extracts increased activity. ZnSO4 was very inhibitory to enzyme activity; CuSO4 was somewhat less inhibitory, and the least effective of the three was MnCl2. The dimer of the tripeptide was converted to a penicillin that has the biological spectrum of isopenicillin N, and this reaction was also stimulated by FeSO4. We found that sonication can be used directly to prepare extracts with cyclization activity from mycelia, without preparing protoplast lysates. The kinetics of cyclase appearance and disappearance during fermentation were similar to those of ring-expansion activity, i.e., enzyme appeared and peaked 13 h after growth ceased and then disappeared.

Acremonium↗

PubMed1962

Biosynthesis of Cephalosporin C: I. Factors Affecting the Fermentation.

A series of complex and synthetic media have been developed that are suitable for the production of cephalosporin C and cephalosporin N by a mutant strain of Cephalosporium (C.M.I. 49,137). dl-Methionine increased the yield of both antibiotics, with more effect on cephalosporin N. l-Cystine had a greater enhancing effect on formation of cephalosporin C than on formation of cephalosporin N in synthetic media; serine increased yields of cephalosporin C under certain conditions. Disaccharides or polysaccharides appeared to be the best source for carbohydrates. No evidence was found for precursor action such as is found in penicillin fermentations. The ability of resting cells to produce antibiotic was demonstrated.

Journal Article↗

PubMed1966

Formation of 6-aminopenicillanic acid, penicillins, and penicillin acylase by various fungi.

Several penicillin-producing fungi were examined for ability to produce 6-aminopenicillanic acid (6-APA) and penicillin acylase. 6-APA was found in corn steep liquor fermentations of Trichophyton mentagrophytes, Aspergillus ochraceous, and three strains of Penicillium sp. 6-APA was not detected in fermentations of Epidermophyton floccosum although penicillins were produced. 6-APA formed a large part of the total antibiotic production of T. mentagrophytes. The types of penicillins produced by various fungi were identified by paper chromatography, and it was found that all cultures produced benzylpenicillin. T. mentagrophytes and A. ochraceous showed increased yields of benzylpenicillin and the formation of phenoxymethylpenicillin in response to the addition to the fermentation medium of phenylacetic acid and phenoxyacetic acid, respectively. Washed mycelia of the three Penicillium spp. and two high penicillin-yielding strains of P. chrysogenum possessed penicillin acylase activity against phenoxymethylpenicillin. A. ochraceous, T. mentagrophytes, E. floccosum, and Cephalosporium sp. also had penicillin acylase activity against phenoxymethylpenicillin. Only two of the above fungi, T. mentagrophytes and E. floccosum, showed significant penicillin acylase activity against benzylpenicillin; in both cases it was very low. The acylase activity of A. ochraceous was considerably increased by culturing in the presence of phenoxyacetic acid. It is concluded that 6-APA frequently but not invariably accompanies the formation of penicillin, and that penicillin acylase activity against phenoxymethylpenicillin is present in all penicillin-producing fungi.

Acremonium↗