| purification and characterization of delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase from penicillium chrysogenum. | delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase (acvs) from penicillium chrysogenum was purified to homogeneity by a combination of (nh4)2so4 precipitation, protamine sulphate treatment, ion-exchange chromatography, gel filtration and hydrophobic interaction chromatography. the molecular mass of acvs was estimated with native gradient gel electrophoresis and sds/page. the native enzyme consisted of a single polymer chain with an estimated molecular mass of 470 kda. the denatured enzy ... | 1997 | 9355751 |
| synthesis of some biologically active agents derived from thieno[2,3-d]pyrimidine derivatives. | the key compound 1-amino-8-iminocyclopenta[b]thieno[2,3-d]pyrimidine (5g) was prepared by reaction of 2-amino-3-cyano cyclopenta[b]thiophene (1) with triethyl orthoformate followed by cyclization with hydrazine hydrate in ethanol. refluxing of 1 with triethyl orthoformate in the presence of acetic anhydride gave an unexpected product 2. while reaction with aromatic amines gave the condensation products 4a-c. reaction of 5g with formic acid, other formate derivatives, ethoxymethylenemalononitrile ... | 1997 | 9362089 |
| necrotizing pneumonia caused by penicillium chrysogenum. | we report a case of necrotizing pneumonia due to penicillium chrysogenum in a 57-year-old woman operated on for lung cancer. the residual right lower pulmonary lobe was infiltrated by penicillium chrysogenum. the patient underwent a second pulmonary right lobectomy and was successfully treated with oral itraconazole. to our knowledge, this is the first case of pneumonia due to p. chrysogenum. | 1997 | 9399551 |
| expression of the cefg gene is limiting for cephalosporin biosynthesis in acremonium chrysogenum. | the conversion of deacetylcephalosporin c to cephalosporin c is inefficient in most acremonium chrysogenum strains. the cefg gene, which encodes deacetylcephalosporin c acetyltransferase, is expressed very poorly in a. chrysogenum as compared to other genes of the cephalosporin pathway. introduction of additional copies of the cefg gene with its native promoter (in two different constructions with upstream regions of 1056 bp and 538 bp respectively) did not produce a significant increase of the ... | 1997 | 9421924 |
| evolving enzyme technology for pharmaceutical applications: case studies. | the case studies focus on two types of enzyme applications for pharmaceutical development. demethylmacrocin o-methyltransferase, macrocin o-methyltransferase (both putatively rate-limiting) and tylosin reductase were purified from streptomyces fradiae, characterized and the genes manipulated for increasing tylosin biosynthesis in s. fradiae. the rate-limiting enzyme, deacetoxycephalosporin c (daoc) synthase/hydroxylase (expandase/ hydroxylase), was purified from cephalosporium acremonium, its ge ... | 1997 | 9451830 |
| isolation and analysis of xlnr, encoding a transcriptional activator co-ordinating xylanolytic expression in aspergillus niger. | complementation by transformation of an aspergillus niger mutant lacking xylanolytic activity led to the isolation of the xlnr gene. the xlnr gene encodes a polypeptide of 875 amino acids capable of forming a zinc binuclear cluster domain with similarity to the zinc clusters of the gal4 superfamily of transcription factors. the xlnr-binding site 5'-ggctaaa-3' was deduced after electrophoretic mobility shift assays, dnase i footprinting and comparison of various xylanolytic promoters. the importa ... | 1998 | 9466262 |
| process models for production of beta-lactam antibiotics. | great progress has been made in the modelling of biotechnical processes using filamentous microorganisms. this paper deals with cultivations of penicillium chrysogenum for the production of penicillin and of acremonium chrysogenum for the production of cephalosporin c. the properties of the processes and the existing models are reviewed. models are presented for both processes that consider aspects which are important for industrial cultivation. the process model for penicillin production is bas ... | 1998 | 9468802 |
| elimination of microorganisms from dental operatory compressed air. | compressed air is used to power high-speed handpieces, as well as to dry and clean surfaces in the oral cavity during patient treatment, in all dental operatories. the compressed air used in the dental operatories located in large institutions such as universities or hospitals is generally obtained from a central source, and is produced by continually running compressors. in operatories located in private practice settings, compressed air is obtained from small on-site air compressors, which may ... | 1998 | 9473876 |
| cyclization of alpha-aminoadipic acid into the the delta-lactam 6-oxo-piperidine-2-carboxylic acid by penicillium chrysogenum. | | 1998 | 9544928 |
| sick building syndrome: association of symptoms with serum ige specific to fungi. | | 1998 | 9561392 |
| extracellular phospholipases as universal virulence factor in pathogenic fungi. | microbial pathogens use a number of genetic strategies to invade the host and cause infection. these common themes are found throughout microbial virulence factors. secretion of enzymes, such as phospholipase, has been proposed as one of these themes which is used by bacteria, parasite, and pathogenic fungi. the role of extracellular phospholipase as a potential virulence factor in pathogenic fungi, including candida albicans, cryptococcus neoformans and aspergillus has gained credence recently. ... | 1998 | 9580028 |
| hypersensitivity pneumonitis induced by penicillium notatum antigens in guinea pigs. | data concerning the experimental induction of hypersensitivity pneumonitis in guinea pigs using a glycoprotein derived from penicillium notatum are presented. this antigen was obtained from the mycelial and metabolic products of the cultures passed through a sephadex g-50 column. it was aerosolized for inhalation by adult guinea pigs for 12 weeks to detect specific serum igm, igg and ige antibodies as well as sensitized leukotriene cd4 cells. histopathological studies of the lungs showed interst ... | 1998 | 9580523 |
| enzymatic 7-adca: i said it couldn't be done. | | 1995 | 9634746 |
| production of cephalosporin intermediates by feeding adipic acid to recombinant penicillium chrysogenum strains expressing ring expansion activity. | we demonstrate a novel and efficient bioprocess for production of the cephalosporin intermediates, 7-aminocephalosporanic acid (7-aca) or 7-amino deacetoxycephalosporanic acid (7-adca). the streptomyces clavuligerus expandase gene or the cephalosporium acremonium expandase-hydroxylase gene, with and without the acetyltransferase gene, were expressed in a penicillin production strain of penicillium chrysogenum. growth of these transformants in media containing adipic acid as the side chain precur ... | 1995 | 9634750 |
| the manganese superoxide dismutase from the penicillin producer penicillium chrysogenum. | the antioxidant enzyme superoxide dismutase has been studied in order to define mechanisms for the influence of oxygen on penicillin production. manganese-containing sod activity was purified from penicillin-producing cultures of the filamentous fungus penicillium chrysogenum and reverse genetics was used to identify full-length cdna and genomic clones. sequence analysis revealed a 630-bp orf containing three exons and two introns with fungal consensus splice-site junctions. the deduced amino-ac ... | 1998 | 9644201 |
| in situ detection of protein-dna interactions in filamentous fungi by in vivo footprinting. | the method described here allows the detection of protein-dna interactions in vivo in filamentous fungi. we outline culture conditions and conditions of in vivo methylation that permit uniform modification of all cells in an apically growing, non-uniform organism, and subsequent visualization of protected areas by ligation-mediated pcr. | 1998 | 9685506 |
| spe3, which encodes spermidine synthase, is required for full repression through nre(dit) in saccharomyces cerevisiae. | we previously identified a transcriptional regulatory element, which we call nre(dit), that is required for repression of the sporulation-specific genes, dit1 and dit2, during vegetative growth of saccharomyces cerevisiae. repression through this element is dependent on the ssn6-tup1 corepressor. in this study, we show that sin4 contributes to nre(dit)-mediated repression, suggesting that changes in chromatin structure are, at least in part, responsible for regulation of dit gene expression. in ... | 1998 | 9725830 |
| molecular regulation of beta-lactam biosynthesis in filamentous fungi. | the most commonly used beta-lactam antibiotics for the therapy of infectious diseases are penicillin and cephalosporin. penicillin is produced as an end product by some fungi, most notably by aspergillus (emericella) nidulans and penicillium chrysogenum. cephalosporins are synthesized by both bacteria and fungi, e.g., by the fungus acremonium chrysogenum (cephalosporium acremonium). the biosynthetic pathways leading to both secondary metabolites start from the same three amino acid precursors an ... | 1998 | 9729600 |
| cloning and disruption of caplb1, a phospholipase b gene involved in the pathogenicity of candida albicans. | the candida albicans plb1 gene was cloned using a polymerase chain reaction-based approach relying on degenerate oligonucleotide primers designed according to the amino acid sequences of two peptide fragments obtained from a purified candidal enzyme displaying phospholipase activity (mirbod, f., banno, y., ghannoum, m. a., ibrahim, a. s., nakashima, s., yasuo, k., cole, g. t., and nozawa, y. (1995) biochim. biophys. acta 1257, 181-188). sequence analysis of a 6.7-kilobase pair ecori-clai genomic ... | 1998 | 9748287 |
| ige-sensitization to cellular and culture filtrates of fungal extracts in patients with atopic dermatitis. | patients with atopic dermatitis may experience exacerbations of eczema triggered by various inflammatory stimuli. one mechanism may be ige-mediated reactions to dermatophytes since these patients are more likely to acquire skin infections with dermatophytes and may become sensitized. | 1998 | 9759803 |
| saprophytic and cycloheximide resistant fungi isolated from golden hamster. | healthy hair samples from golden hamsters were examined for the presence of dermatophytes and non-dermatophytes using baiting technique and direct inoculation. thirty-four species and 2 varieties attributed to 17 genera were recovered. paecilomyces variotii (isolated from 84.4% of the examined hair) and aspergillus niger (81.3%) were the more frequent isolates on sabouraud's dextrose agar (sda) without cycloheximide. our results have clearly demonstrated that the hair of hamster was free from tr ... | 1998 | 9768288 |
| enhanced penicillin production by oligosaccharides from batch cultures of penicillium chrysogenum in stirred-tank reactors. | alginate and galactomannan-derived oligosaccharides enhanced the production of penicillin g when added to stirred tank reactor cultures of penicillium chrysogenum. the addition of oligomannuronate and oligoguluronate blocks increased penicillin g yield by 47% and 49%, respectively. the effect of mannan oligosaccharides was found to be more pronounced with 69% higher yield than the control cultures. the maximum increase in the average specific productivity of the oligosaccharide augmented culture ... | 1998 | 9776634 |
| adenosine 5'-phosphosulfate kinase from penicillium chrysogenum. site-directed mutagenesis at putative phosphoryl-accepting and atp p-loop residues. | the properties of penicillium chrysogenum adenosine 5'-phosphosulfate (aps) kinase mutated at ser-107 were examined. ser-107 is analogous to a serine of the e. coli enzyme that has been shown to serve as an intermediate acceptor in the transfer of a phosphoryl group from atp to aps. replacement of ser-107 with alanine yielded an active enzyme with kinetic characteristics similar to those of wild-type aps kinase. another mutant form of the enzyme in which ser-107 was replaced by cysteine was also ... | 1998 | 9786849 |
| characterization of the lys2 gene of penicillium chrysogenum encoding alpha-aminoadipic acid reductase. | a dna fragment containing a gene homologous to lys2 gene of saccharomyces cerevisiae was cloned from a genomic dna library of penicillium chrysogenum as-p-78. it encodes a protein of 1409 amino acids (mr 154859) with strong similarity to the s. cerevisiae (49.9% identity) schizosaccharomyces pombe (51.3% identity) and candida albicans (48.12% identity) alpha-aminoadipate reductases and a lesser degree of identity to the amino acid-activating domains of the non-ribosomal peptide synthetases, incl ... | 1998 | 9790587 |
| studies on toxigenic fungi in roasted foodstuff (salted seed) and halotolerant activity of emodin-producing aspergillus wentii. | commercial roasted salted peanuts (3% nacl), popcorn (1% nacl), summer-squash (9% nacl), sunflower (3% nacl) and wild-melon (3% nacl) seeds are polluted with fungi, mostly aspergillus flavus, a. niger, penicillium chrysogenum, p. corylophilum and rhizopus stolonifer. contamination of popcorn with the fungi is about 10 times higher than in the other foods. these fungi, common also on unsalted seeds, are significantly inhibited in seeds (30% moisture content) treated with 9-21% nacl. the halotoler ... | 1998 | 9821293 |
| evaluation of proteolytic activity of micro-organisms isolated from dry cured ham. | in order to determine the possible contribution of micro-organisms to the ripening of meat products, 48 cocci, 18 moulds and 20 yeasts isolated from dry-cured iberian ham were evaluated for proteolytic activity. two specific methods were used: the ability to hydrolyse myosin in broth and, for those strains showing high activities, hydrolysis on both myofibrillar and sarcoplasmic proteins on pork slices. moulds and cocci showed the highest proteolytic activity for myosin in broth. both myofibrill ... | 1998 | 9830127 |
| the optimization of penicillin biosynthesis in fungi. | penicillin production by penicillium chrysogenum is not only commercially important but arguably the most intensively investigated secondary-metabolic pathway in fungi. isolation of the structural genes encoding the three main penicillin-biosynthetic enzymes has stimulated the use of molecular approaches to optimize yield and permitted genetic analysis of current production strains, which are themselves the products of 50 years of strain and process improvement. parallel studies on the penicilli ... | 1998 | 9830157 |
| repression of the expression of genes encoding xylanolytic enzymes in aspergillus oryzae by introduction of multiple copies of the xynf1 promoter. | a xylanase gene, xynf1, was cloned and characterized from a shoyu koji mould aspergillus oryzae kbn616. the xynf1 gene was found to be comprised of 1484 bp with ten introns. the deduced amino acid sequence encodes a protein consisting of 327 amino acids (35,402 da) which is very similar to the fungal family f xylanases such as aspergillus nidulans xlnc, aspergillus kawachii xyna and penicillium chrysogenum xylp. the intron/exon organization of xynf1 is very similar to that of the fungal family f ... | 1998 | 9866173 |
| adenosine 5'-phosphosulfate (aps) kinase: diagnosing the mechanism of substrate inhibition. | adenosine 5'-phosphosulfate (aps) kinase is subject to strong substrate inhibition by aps. the inhibition has been variously reported to be uncompetitive with respect to mgatp (resulting from the formation of a dead-end e. aps. mgadp complex) or competitive with mgatp (resulting from the formation of a dead-end e. aps complex). it is shown that these two types of substrate inhibition can be differentiated for ordered kinetic mechanisms by simple inspection of the v versus [aps] plots at differen ... | 1999 | 9882457 |
| [residential colonization of orbital complex "mir" environment by penicillium chrysogenum and problem of ecological safety in long-term space flight]. | results of many years of the survey of highly specific evolution of quantitative and species composition of microflora of the mir environment are reviewed. analysis of the data enabled listing of microorganisms-declinous fungi with the ability of residential colonization of structural materials of the interior and equipment of habitable modules of the space station. results of the studies of variability and level of similarity/affinity on the basis of dna, polymorphism of strains isolated in spa ... | 1998 | 9883336 |
| characterization and lysine control of expression of the lys1 gene of penicillium chrysogenum encoding homocitrate synthase. | a 2071-bp dna fragment, containing a gene (lys1) encoding a protein that showed 71.1% identical amino acids with the yarrowia lipolytica homocitrate synthase and 71.7% identity with the saccharomyces cerevisiae homologous enzyme, was cloned from a genomic library of penicillium chrysogenum. the lys1 gene contained three introns and encoded a protein of 474 amino acids with a deduced molecular mass of 52kda. lys1 was located in chromosome ii (9.6mb) in the wild-type p. chrysogenum nrrl 1951, wher ... | 1999 | 9889317 |
| gene targeting in penicillium chrysogenum: disruption of the lys2 gene leads to penicillin overproduction. | two strategies have been used for targeted integration at the lys2 locus of penicillium chrysogenum. in the first strategy the disruption of lys2 was obtained by a single crossing over between the endogenous lys2 and a fragment of the same gene located in an integrative plasmid. lys2-disrupted mutants were obtained with 1.6% efficiency when the lys2 homologous region was 4.9 kb, but no homologous integration was observed with constructions containing a shorter homologous region. similarly, lys2- ... | 1999 | 9973344 |
| organization of the gene cluster for biosynthesis of penicillin in penicillium nalgiovense and antibiotic production in cured dry sausages. | several fungal isolates obtained from two cured meat products from spain were identified as penicillium nalgiovense by their morphological features and by dna fingerprinting. all p. nalgiovense isolates showed antibiotic activity in agar diffusion assays, and their penicillin production in liquid complex medium ranged from 6 to 38 microgram. ml-1. we constructed a restriction map of the penicillin gene cluster of p. nalgiovense and found that the organization of the penicillin biosynthetic genes ... | 1999 | 10049889 |
| isolation, characterization and disruption of the area nitrogen regulatory gene of gibberella fujikuroi. | the gene area-gf, a homologue of the major nitrogen regulatory genes nit-2, area, nre and nut1 of neurospora crassa, aspergillus nidulans, penicillium chrysogenum and magnaporthe grisea, respectively, was cloned from the gibberellin (ga)-producing rice pathogen gibberella fujikuroi. area-gf encodes a protein of 972 amino acid residues which contains a single putative zinc finger dna-binding domain that is at least 98% identical to the zinc finger domains of the homologous fungal proteins. the ar ... | 1999 | 10071216 |
| transcription of the pcbab, pcbc and pende genes of penicillium chrysogenum as-p-78 is repressed by glucose and the repression is not reversed by alkaline phs. | glucose repressed transcription of the penicillin biosynthesis genes pcbab, pcbc and pende when added at inoculation time to cultures of penicillium chrysogenum as-p-78 but it had little repressive effect when added at 12 h and no effect when added at 24 or 36 h. a slight increase in the expression of pcbc and pende (and to a smaller extent of pcbab) was observed in glucose-grown cultures at ph 6.8, 7.4 and 8.0 as compared with ph 6.2, but alkaline phs did not override the strong repression exer ... | 1999 | 10075414 |
| measurement of autolysis in submerged batch cultures of penicillium chrysogenum. | the process of cellular autolysis was studied in an industrial strain of penicillium chrysogenum by a range of methods, including assessment of biomass decline, nh+4 release, changes in culture apparent viscosity, and by means of a quantitative assessment of changes in micromorphology using a computerized image analysis system. the pattern of total intracellular proteolytic and beta-1, 3-glucanolytic activity in the culture was also examined. the overall aim was to identify a suitable method, or ... | 1998 | 10099206 |
| dependence of penicillium chrysogenum growth, morphology, vacuolation, and productivity in fed-batch fermentations on impeller type and agitation intensity | the influence of the agitation conditions on the growth, morphology, vacuolation, and productivity of penicillium chrysogenum has been examined in 6 l fed-batch fermentations. a standard rushton turbine, a four-bladed paddle, and a six-bladed pitched blade impeller were compared. power inputs per unit volume of liquid, p/vl, ranged from 0.35 to 7.4 kw/m3. the same fermentation protocol was used in each fermentation, including holding the dissolved oxygen concentration above 40% air saturation by ... | 1998 | 10099397 |
| uptake of phenylacetic acid by two strains of penicillium chrysogenum. | uptake of phenylacetic acid, the side-chain precursor of benzylpenicillin, was studied in penicillium chrysogenum wisconsin 54-1255 and in a strain yielding high levels of penicillin. in penicillin fermentations with the high-yielding strain, 100% recovery of phenylacetic acid in benzylpenicillin was found, whereas in the wisconsin strain only 17% of the supplied phenylacetic acid was incorporated into benzylpenicillin while the rest was metabolized. accumulation of total phenylacetic acid-deriv ... | 1998 | 10099433 |
| modelling of the protonophoric uncoupling by phenoxyacetic acid of the plasma membrane potential of penicillium chrysogenum. | physiological effects of phenoxyacetic acid, the penicillin v side-chain precursor, on steady-state continuous cultures of penicillium chrysogenum have been studied both theoretically and experimentally. theoretical calculations show that at an extracellular ph of 6.50, phenoxyacetic acid has negligible influence on the growth energetics due to protonophoric uncoupling of membrane potentials by passive diffusive uptake. on the other hand, when the extracellular ph is lowered to 5.00, a severe ma ... | 1998 | 10099485 |
| analysis of the oxidative stress response of penicillium chrysogenum to menadione. | the intracellular superoxide and glutathione disulphide concentrations increased in penicillium chrysogeum treated with 50, 250 or 500 microm menadione (mq). a significant increase in the intracellular peroxide concentration was also observed when mycelia were exposed to 250 or 500 microm mq. the specific activity of cu,zn and mn superoxide dismutases, glutathione reductase and glutathione s-transferase as well as the glutathione producing activity increased in the presence of mq while glutathio ... | 1999 | 10193580 |
| molecular cloning of a second phospholipase b gene, caplb2 from candida albicans. | accumulating evidence suggests that phospholipase b, secreted by pathogenic fungi such as candida albicans, cryptococcus neoformans and aspergillus fumigatus, functions as one of the virulence factors. in the present study, we have attempted to clone phospholipase b gene from c. albicans. by rt-pcr analysis with degenerate primers based on conserved regions of phospholipase b from saccharomyces cerevisiae, penicillium notatum and torulaspora delbrueckii two similar but different cdna fragments w ... | 1999 | 10200936 |
| influence of microbial concentration on the rheology of non-newtonian fermentation broths. | the objective of this study was to quantify the effect of fungal biomass concentration on the rheology of non-newtonian fermentation systems. batch fermentations of penicillium chrysogenum were carried out with glucose as the sole carbon source. the flow behavior of the system was characterized at various fermentation times and was adequately described by the power-law model. the apparent viscosity of the fermentation broth was significantly affected by biomass concentrations in the fermenter. f ... | 1999 | 10222579 |
| characterization of allergens from penicillium oxalicum and p. notatum by immunoblotting and n-terminal amino acid sequence analysis. | penicillium species are important causative agents of extrinsic bronchial asthma. however, little is known about the allergens of these ubiquitous fungal species. objective the object was to analyse the composition, the allergenic cross-reactivity and the n-terminal sequences of allergens from two prevalent airborne penicillium species, p. oxalicum and p. notatum. | 1999 | 10231324 |
| disruption of phaca, an aspergillus nidulans gene encoding a novel cytochrome p450 monooxygenase catalyzing phenylacetate 2-hydroxylation, results in penicillin overproduction. | aspergillus nidulans utilizes phenylacetate as a carbon source via homogentisate, which is degraded to fumarate and acetoacetate. mutational evidence strongly suggested that phenylacetate is converted to homogentisate through two sequential hydroxylating reactions in positions 2 and 5 of the aromatic ring. using cdna substraction techniques, we have characterized a gene, denoted phaca, whose transcription is strongly induced by phenylacetate and which putatively encodes a cytochrome p450 protein ... | 1999 | 10329644 |
| molecular mechanisms of chromosomal rearrangement in fungi. | both sexual and asexual fungi undergo chromosomal rearrangements, which are the main cause of karyotype variability among the populations. different recombination processes can produce chromosomal reorganizations, both during mitosis and meiosis, but other mechanisms operate to limit the extent of the rearrangements; some of these mechanisms, such as the rip (repeat-induced point mutations) of neurospora crassa, have been well established for sexual fungi. in laboratory strains, treatments such ... | 1999 | 10342097 |
| microfungal contamination of damp buildings--examples of risk constructions and risk materials. | to elucidate problems with microfungal infestation in indoor environments, a multidisciplinary collaborative pilot study, supported by a grant from the danish ministry of housing and urban affairs, was performed on 72 mold-infected building materials from 23 buildings. water leakage through roofs, rising damp, and defective plumbing installations were the main reasons for water damage with subsequent infestation of molds. from a score system assessing the bioavailability of the building material ... | 1999 | 10347000 |
| biotransformation of the diperpenoid, isosteviol, by aspergillus niger, penicillium chrysogenum and rhizopus arrhizus. | the biotransformation of isosteviol (ent-16-ketobeyeran-19-oic acid) by three fungi is described. aspergillus niger produced the 7 beta-oh derivative, ent-7 alpha-hydroxy-16-ketobeyeran-19-oic, and the 1 alpha, 7 beta-dioh derivative, ent-1 beta, 7 alpha-dihydroxy-16-ketobeyeran-19-oic acid. the 17-oh compound, ent-17-hydroxy-16-ketobeyeran-19-oic acid, was obtained with penicillium chrysogenum. rhizopus arrhizus produced the 7 beta-oh derivative, ent-7 alpha-hydroxy-16-ketobeyeran-19-oic acid. ... | 1999 | 10389273 |
| aerobiological analysis in a salami factory: a possible case of extrinsic allergic alveolitis by penicillium camembertii. | a 39-year-old man was hospitalized with a history of fatigue, dyspnoea and low grade fever which seemed to be related to his working environment. the patient was employed in a salami factory, working near the area where the salami are seasoned with fungal inocula. chest x-ray showed diffuse initial changes of reticulonodular pattern that disappeared after a brief course of steroids therapy. precipitating antibodies to penicillium notatum and aspergillus fumigatus were found both in plasma and br ... | 1999 | 10421864 |
| the beta-lactam antibiotics: past, present, and future. | the discovery and development of the beta-lactam antibiotics are among the most powerful and successful achievements of modern science and technology. since fleming's accidental discovery of the penicillin-producing mold, seventy years of steady progress has followed, and today the beta-lactam group of compounds are the most successful example of natural product application and chemotherapy. following on the heels of penicillin production by penicillium chrysogenum came the discoveries of cephal ... | 1999 | 10422578 |
| penicillin and cephalosporin biosynthesis: mechanism of carbon catabolite regulation of penicillin production. | penicillins and cephalosporins are synthesized by a series of enzymatic reactions that form the tripeptide delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine and convert this tripeptide into the final penicillin or cephalosporin molecules. one of the enzymes, isopenicillin n synthase has been crystallyzed and its active center identified. the three genes pcbab, pcbc and pende involved in penicillin biosynthesis are clustered in penicillium chrysogenum, aspergillus nidulans and penicillium nalgiove ... | 1999 | 10422579 |
| compartmentalization and transport in beta-lactam antibiotic biosynthesis by filamentous fungi. | a proper description of the biosynthesis of fungal beta-lactam antibiotics requires detailed knowledge of the cell biology of the producing organisms. this involves a delineation of the compartmentalization of the biosynthetic pathways, and of the consequential transport steps across the cell-boundary plasma membrane and across organellar membranes. of the enzymes of the penicillin biosynthetic pathway in penicillium chrysogenum and aspergillus nidulans, delta-(l-alpha-aminoadipyl)-l-cysteinyl-d ... | 1999 | 10422581 |
| gene organization and plasticity of the beta-lactam genes in different filamentous fungi. | the genes pcbab, pcbc and pende encoding enzymes that catalyze the three steps of the penicillin biosynthesis have been cloned from penicillium chrysogenum and aspergillus nidulans. they are located in a cluster in penicillium chrysogenum, penicillium notatum, aspergillus nidulans and penicillium nalgiovense. the three genes are clustered in chromosome i (10.4 mb) of p. chrysogenum, in chromosome ii of p. notatum (9.6 mb) and in chromosome vi (3.0 mb) of a. nidulans. the cluster of the penicilli ... | 1999 | 10422582 |
| transcriptional control of expression of fungal beta-lactam biosynthesis genes. | the most commonly used beta-lactam antibiotics for the therapy of infectious diseases are penicillin and cephalosporin. penicillin is produced as end product by some fungi most notably by aspergillus (emericella) nidulans and penicillium chrysogenum. cephalosporins are synthesised by several bacteria and fungi, e.g. by the fungus acremonium chrysogenum (syn. cephalosporium acremonium). the biosynthetic pathways leading to both secondary metabolites start from the same three amino acid precursors ... | 1999 | 10422583 |
| biosynthesis and molecular genetics of cephamycins. cephamycins produced by actinomycetes. | cephamycin c is produced in a nine steps pathway by the actinomycetes s. clavuligerus and n. lactamdurans. the genes encoding the biosynthesis enzymes are clustered in both microorganisms as well as in the cephabacin producer lysobacter lactamgenus, a gram negative bacterium. the clusters of genes include genes encoding enzymes common to the biosynthesis of penicillin and cephalosporin c by the eukaryotic producers penicillium chrysogenum and cephalosporium acremonium and genes for steps specifi ... | 1999 | 10422584 |
| metabolic control analysis of the penicillin biosynthetic pathway: the influence of the lld-acv:bisacv ratio on the flux control. | an extended kinetic model for the first two steps of the penicillin biosynthetic pathway in penicillium chrysogenum is set up. it includes the formation and reduction of the dimer bis-delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine (bisacv) from the first pathway intermediate lld-acv and their parallel inhibition of the enzyme acv synthetase (acvs). the kinetic model is based on michaelis-menten type kinetics, with non-competitive inhibition of the acvs by both lld-acv and bisacv, and competiti ... | 1999 | 10422587 |
| case report: cutaneous penicilliosis due to penicillium chrysogenum. | a case of cutaneous penicilliosis in a young man, without immunological compromise is reported. the lesions in the neck were characterized by two exudative reddish-purple pruriginous and painless spots. penicilliosis was diagnosed after serial laboratory studies based on the observation of hyphae by direct microscopic examination and histopathology. cultures of the tissue obtained from the lesions, developed mould colonies with typical conidia of penicillium chrysogenum, which was thermotolerant ... | 1999 | 10424109 |
| kinetics of alpha-amylase secretion in aspergillus oryzae. | pulse and pulse-chase experiments have been performed to study l-[(35)s] methionine incorporation and protein secretion kinetics in aspergillus oryzae. pulse experiments confirmed the mechanism of methionine uptake reported previously for penicillium chrysogenum (benko et al., 1967). pulse-chase experiments were carried out to investigate the alpha-amylase secretion kinetics in a. oryzae. no unglycosylated alpha-amylase was detected neither intracellularly nor extracellularly demonstrating that ... | 1999 | 10440673 |
| evaluation of different methods for the extraction of dna from fungal conidia by quantitative competitive pcr analysis. | five different dna extraction methods were evaluated for their effectiveness in recovering pcr templates from the conidia of a series of fungal species often encountered in indoor air. the test organisms were aspergillus versicolor, penicillium chrysogenum, stachybotrys chartarum, cladosporium herbarum and alternaria alternata. the extraction methods differed in their use of different cell lysis procedures. these included grinding in liquid nitrogen, grinding at ambient temperature, sonication, ... | 1999 | 10445315 |
| evaluation of ige-sensitization to fungi in hiv-positive patients with eczematous skin reactions. | human immunodeficiency virus infection is associated with declining immune function and polyclonal b-cell activation leading to elevated ige-levels. in selected patient categories, increased total ige may be associated with allergic diseases. furthermore, a significant number of patients with low cd4+ cell numbers have various skin manifestations, eg, eczema and dermatophytosis. patients with chronic fungal infections and a tendency to produce increased levels of specific ige may become allergic ... | 1999 | 10480590 |
| intrachromosomal recombination between direct repeats in penicillium chrysogenum: gene conversion and deletion events. | recombination between direct repeats has been studied in penicillium chrysogenum using strain td7-88 (lys- py+), which contains two inactive copies of the lys2 gene separated by 4.5 kb of dna (including the pyrg gene) in its genome. gene conversion leading to products with the lys+ pyr+ phenotype was observed at a frequency of 1 in 3.2x10(3) viable spores. two types of deletion events giving rise to lys+ pyr- and lys- pyr- phenotypes were obtained with different frequencies. southern analysis re ... | 1999 | 10485291 |
| fungal utilization of organophosphate pesticides and their degradation by aspergillus flavus and a. sydowii in soil. | fungal species were isolated which utilize organophosphate pesticides, viz. phosphorothioic (pirimiphos-methyl and pyrazophos), phosphorodithioic (dimethoate and malathion), phosphonic (lancer) and phosphoric (profenfos) acid derivatives. pesticide degradation was studied in vitro and in vivo (soil). aspergillus flavus, a. fumigatus, a. niger, a. sydowii, a. terreus, emericella nidulans, fusarium oxysporum and penicillium chrysogenum were isolated from pesticide-treated wheat straw. the number o ... | 1999 | 10489696 |
| molecular tools for identification of penicillium starter cultures used in the food industry. | the main goal of this work was to develop rapid and accurate molecular tools to discriminate species of white industrial penicillia. we applied three different polymerase chain reaction (pcr) based techniques. sequences of the its region of the rrna gene unit and of the 5' end of the beta tubulin gene yielded 1.2% and 5.8% nucleotide variability respectively, between penicillium camembertii and penicillium nalgiovense. polymorphic restriction sites were found in both sequences. these may be used ... | 1999 | 10490221 |
| the nadp-dependent glutamate dehydrogenase gene from penicillium chrysogenum and the construction of expression vectors for filamentous fungi. | the gdha gene encoding the nadp-dependent glutamate dehydrogenase activity from penicillium chrysogenum has been isolated and characterized for its use in gene expression. the nucleotide sequence of a 2816-bp genomic fragment was determined, showing an open reading frame of 1600 bp interrupted by two introns, of 160 bp and 57 bp respectively, with fungal consensus splice-site junctions. the predicted amino acid sequence revealed a high degree of identity to glutamate dehydrogenase enzymes, espec ... | 1999 | 10499259 |
| isolation and characterization of a novel antifungal peptide from aspergillus niger. | a novel antifungal peptide (termed as anafp) was isolated from the culture supernatant of the filamentous fungi, aspergillus niger. the whole amino acid sequence of anafp was determined and the peptide was found to be composed of a single polypeptide chain with 58 amino acids including six cysteine residues. the peptide shows some degree of sequence homology to a cysteine-rich antifungal peptides reported from the seeds of sinapis alba and arabidopsis thaliana or the extracellular media of asper ... | 1999 | 10512732 |
| effect of phenylacetic acid feeding on the process of cellular autolysis in submerged batch cultures of penicillium chrysogenum. | the effects of feeding the 'toxic' penicillin precursor, phenylacetic acid (paa) at varying rates, upon the process of cellular autolysis, was assessed in batch bioreactor cultures of an industrial strain of penicillium chrysogenum. five processes were fed at rates which resulted in extracellular concentrations of paa ranging from zero (the control) to approximately ten times levels said to be optimal for penicillin biosynthesis. the culture response was assessed chemically and morphologically, ... | 1999 | 10553656 |
| production of mycotoxins on artificially and naturally infested building materials. | in this study, the ability to produce mycotoxins during growth on artificially infested building materials was investigated for penicillium chrysogenum, pen. polonicum, pen. brevicompactum, chaetomium spp., aspergillus ustus, asp. niger, ulocladium spp., alternaria spp., and paecilomyces spp., all isolated from water-damaged building materials. spores from the different isolates of the above mentioned species were inoculated on gypsum board with and without wallpaper and on chipboard with and wi ... | 1999 | 10560628 |
| antimicrobial activity of selected cyclic dipeptides. | cyclic dipeptides are products of rational drug design, which may exhibit both antimicrobial and antitumor properties. the aim of this study was to investigate both the antimicrobial effects of the cyclic dipeptides cyclo(l-phenylalanyl-l-prolyl), cyclo(l-tyrosyl-l-prolyl), cyclo(l-tryptophanyl-l-prolyl) and cyclo(l-tryptophanyl-l-tryptophanyl) and the effects of these cyclic dipeptides on the gastrointestinal epithelium in vitro. furthermore, a relevant solvent for the possible pharmaceutical a ... | 1999 | 10563376 |
| sulfate transport in penicillium chrysogenum: cloning and characterization of the suta and sutb genes. | in industrial fermentations, penicillium chrysogenum uses sulfate as the source of sulfur for the biosynthesis of penicillin. by a pcr-based approach, two genes, suta and sutb, whose encoded products belong to the sulp superfamily of sulfate permeases were isolated. transformation of a sulfate uptake-negative sb3 mutant of aspergillus nidulans with the sutb gene completely restored sulfate uptake activity. the suta gene did not complement the a. nidulans sb3 mutation, even when expressed under c ... | 1999 | 10572125 |
| sensitization to local dust-mite fauna in singapore. | recent studies showed the presence of a unique dust-mite fauna in the indoor environment of singapore. immediate hypersensitivity to these dust mites, along with other known indoor allergens, may play a role in the pathogenesis of allergic respiratory diseases. this study evaluated the sensitization rates of the local atopic population to these allergens. | 1999 | 10604550 |
| a novel heptameric sequence (ttagtaa) is the binding site for a protein required for high level expression of pcbab, the first gene of the penicillin biosynthesis in penicillium chrysogenum. | the first two genes pcbab and pcbc of the penicillin biosynthesis pathway are expressed from a 1.01-kilobase bidirectional promoter region. a series of sequential deletions were made in the pcbab promoter region, and the constructions with the modified promoters coupled to the lacz reporter gene were introduced as single copies at the pyrg locus in penicillium chrysogenum npe10. three regions, boxes a, b, and c, produced a significant decrease in expression of the reporter gene when deleted. pro ... | 2000 | 10644695 |
| [different age of asthmatic patients affected by different aeroallergens]. | a total of 1070 cases of bronchial asthma, aged from 3 to 70 years, were analyzed for their hypersensitivity to the four most common aeroallergens, dermatophagoides pteronyssinus, german cockroaches, penicillium notatum and candida albicans. the severity of hypersensitivity was classified as mild, moderate and severe based on the concentration of allergen specific ige in the sera. results showed that there were 77.9% patients allergic to d. pteronyssinus, 40.0% to g. cockroaches, 9.6% to p. nota ... | 1999 | 10650494 |
| crystal structure of adenosine 5'-phosphosulfate kinase from penicillium chrysogenum. | adenosine 5'-phosphosulfate (aps) kinase catalyzes the second reaction in the two-step conversion of inorganic sulfate to 3'-phosphoadenosine 5'-phosphosulfate (paps). this report presents the 2.0 a resolution crystal structure of ligand-free aps kinase from the filamentous fungus, penicillium chrysogenum. the enzyme crystallized as a homodimer with each subunit folded into a classic kinase motif consisting of a twisted, parallel beta-sheet sandwiched between two alpha-helical bundles. the walke ... | 2000 | 10677210 |
| characterization of pen n 13, a major allergen from the mold penicillium notatum. | penicillium notatum is a well-known indoor aeroallergen and is frequently included in skin test panels for allergic diagnosis. on two-dimensional immunoblotting using patients' sera containing ige and monoclonal antibody d7b8 specific for pen c 1 of p. citrinum, two allergens with a molecular mass of 33 kda but different isoelectric points were identified. a novel cdna coding for pen n 13 was cloned and sequenced. the nucleotide sequence codes for a protein 397 amino acids including a putative s ... | 2000 | 10694469 |
| the true history of the discovery of penicillin, with refutation of the misinformation in the literature. | in 1928, while investigating variant strains of staphylococcus aureus, alexander fleming found that a fungus growing near the edge of a culture of s. aureus produced a substance which had diffused into the medium, lysed the nearest organisms and thus produced a clear area immediately surrounding the fungus. further away was a zone of transparent, degenerate colonies, while those in the outer zone appeared healthy. this culture plate was one of several left on his laboratory bench at room tempera ... | 1999 | 10695047 |
| the specific transport system for lysine is fully inhibited by ammonium in penicillium chrysogenum: an ammonium-insensitive system allows uptake in carbon-starved cells. | the regulation exerted by ammonium and other nitrogen sources on amino acid utilization was studied in swollen spores of penicillium chrysogenum. ammonium prevented the l-lysine, l-arginine and l-ornithine utilization by p. chrysogenum swollen spores seeded in complete media, but not in carbon-deficient media. transport of l-[14c]lysine into spores incubated in presence of carbon and nitrogen sources was fully inhibited by ammonium ions (35 mm). however, in carbon-derepressed conditions (growth ... | 2000 | 10696883 |
| role of proteases in autolysis of penicillium chrysogenum chemostat cultures in response to nutrient depletion. | an industrial strain of penicillium chrysogenum was subjected to carbon or nitrogen limitation in a chemostat and the response monitored in terms of the "classical" indicators of autolysis (biomass decline and ammonia release), culture degradation (as measured by image analysis) and by obtaining profiles for three classes of proteases implicated in autolysis. under both sets of conditions (carbon or nitrogen limitation), once started, autolysis involved a succession of different protease activit ... | 2000 | 10709988 |
| effect of biomass concentration and mycelial morphology on fermentation broth rheology. | the effect of biomass concentration and mycelial morphology on fungal fermentation broth rheological properties has been investigated. in previous work it had been shown that commonly used rheological parameters, such as the power law consistency and flow behavior indices, could be correlated successfully with the broth biomass concentration and clump morphological parameters of roughness and compactness. more recent work on a broader range of data showed a correlation between roughness and comp ... | 2000 | 10712732 |
| allergen-specific ige levels against crude mould and storage mite extracts and recombinant mould allergens in sera from horses affected with chronic bronchitis. | immunoglobulin e antibody (ige) levels against four recombinant (r) mould allergens (r-aspergillus fumigatus [rasp f] 7, 8 and 9; r-alternaria alternata 1 [ralta1]) and crude mould (aspergillus fumigatus, alternaria alternata, penicillium notatum) and storage mite extracts were determined by elisa in sera from 24 pulmonary sound control horses and 26 horses suffering from chronic bronchitis/bronchiolitis (cb), also called chronic obstructive pulmonary disease (copd). serum igg and iga titres wer ... | 2000 | 10713338 |
| the fungal cpcr1 protein, which binds specifically to beta-lactam biosynthesis genes, is related to human regulatory factor x transcription factors. | here we report the isolation and characterization of a novel transcription factor from the cephalosporin c-producing fungus acremonium chrysogenum. we have identified a protein binding site in the promoter of the beta-lactam biosynthesis gene pcbc, located 418 nucleotides upstream of the translational start. using the yeast one-hybrid system, we succeeded in isolating a cdna clone encoding a polypeptide, which binds specifically to the pcbc promoter. the polypeptid shows significant sequence hom ... | 2000 | 10734077 |
| catalytic decomposition of 3-chloroperoxybenzoic acid by immobilized catalase in a non-aqueous medium. | catalytic activities of catalase (cat) immobilized on graphite--gmz, soot--"norit" and "pm-100" to mediate decomposition of 3-cl-c6h4coooh (3-cpba) in acetonitrile have been investigated. under these conditions, the kinetic parameters km, k, ea, vmax, and z0 were calculated. conclusions on a probable mechanism of the catalytic process observed were drawn from the calculated values of deltag*, deltah*, and deltas*. a quantitative uv-spectrophotometrical approach was used as the basic analytical t ... | 2000 | 10739100 |
| dynamic biochemical reaction process analysis and pathway modification predictions. | recently, the area of model predictive modification of biochemical pathways has received attention with the aim to increase the productivity of microbial systems. in this study, we present a generalization of previous work, where, using a sensitivity study over the fermentation as a dynamic system, the optimal selection of reaction steps for modification (amplification or attenuation) is determined. the influence of metabolites in the activity of enzymes has also been considered (through activat ... | 2000 | 10745197 |
| penicillin fermentation: mechanisms and models for industrial-scale bioreactors. | even after many years of research and industrial practice, the production of penicillin g in fed-batch fermentation by penicillium crysogenum continues to attract research interest. there are many reasons: the commercial and therapeutic importance of penicillin and its derivatives, the complexity of cell growth, and the impact of engineering variables, the last of which are significant in large bioreactors but are not yet fully understood. extensive research has generated new information on the ... | 2000 | 10770225 |
| physiological aspects of fungi isolated from root nodules of faba bean (vicia faba l.). | the present study was made to isolate and assess some physiological characteristics of root nodule-colonizing fungi. during this study, 17 fungal species were isolated from root nodule samples taken from faba bean plants (vicia faba l.) collected from different sites at assiut area (egypt). the growth of faba bean plants in pots was significantly promoted by soil inoculation with most fungi. growth was checked in pots with inocula of cladosporium cladosporioides, fusarium moniliforme, f: oxyspor ... | 2000 | 10772156 |
| application of metabolic flux analysis for the identification of metabolic bottlenecks in the biosynthesis of penicillin-g. | a detailed stoichiometric model was developed for growth and penicillin-g production in penicillium chrysogenum. from an a priori metabolic flux analysis using this model it appeared that penicillin production requires significant changes in fluxes through the primary metabolic pathways. this is brought about by the biosynthesis of carbon precursors for the beta-lactan nucleus and an increased demand for nadph, mainly for sulfate reduction. as a result, significant changes in flux partitioning o ... | 2000 | 10799985 |
| metabolic network analysis of penicillium chrysogenum using (13)c-labeled glucose. | using (13)c-labeled glucose fed to a penicillin-overproducing strain of penicillium chrysogenum, the intracellular fluxes were quantified, and the presence of two new pathways, not previously described in this organism, is suggested. thus, glycine was synthesized not only by serine hydroxymethyltransferase, but also by threonine aldolase. the formation of cytosolic acetyl-coa was found to be synthesized both via the citrate lyase-catalyzed reaction and by degradation of the penicillin side-chain ... | 2000 | 10799990 |
| an animal model for allergic penicilliosis induced by the intranasal instillation of viable penicillium chrysogenum conidia. | a study was undertaken to determine the consequences of long term intranasal instillation of penicillium chrysogenum propagules in a mouse model. | 2000 | 10817798 |
| agitation induced mycelial fragmentation of aspergillus oryzae and penicillium chrysogenum. | given the impact of mycelial morphology on fermentation performance, it is important to understand the factors that influence it, including agitation-induced fragmentation. the successful application of the energy dissipation/circulation function (edc) to correlate fragmentation of penicillium chrysogenum with agitation intensity and with different impeller types [5] has already been demonstrated. the edc function takes into account the specific energy dissipation rate in the impeller swept volu ... | 2000 | 10817815 |
| evaluation of the mycological status of luncheon meat with special reference to aflatoxigenic moulds and aflatoxin residues. | the luncheon meat samples analyzed, which were produced locally by the two main luncheon meat producing companies in egypt were relatively highly contaminated either by moulds and yeasts in general, aflatoxigenic species and aflatoxin residues in particular. the most frequently encountered fungi from the samples were yeasts, aspergillus niger, a. flavus, penicillium chrysogenum, rhizopus stolonifer, mucor circinelloides. less common were cladosporium sphaerospermum, alternaria alternata, mycosph ... | 1999 | 10823186 |
| fusarinines and dimerum acid, mono- and dihydroxamate siderophores from penicillium chrysogenum, improve iron utilization by strategy i and strategy ii plants. | cucumber, as a strategy i plant, and maize as a strategy ii plant, were cultivated in hydroponic culture in the presence of a ferrated siderophore mixture (1 microm) from a culture of penicillium chrysogenum isolated from soil. the siderophore mixture significantly improved the iron status of these plants as measured by chlorophyll concentration to the same degree as a 100-fold higher feedta supply. analysis of the siderophore mixture from p. chrysogenum by hplc and electrospray mass spectrometr ... | 2000 | 10831223 |
| continuous production of antibiotics in an airlift fermentor utilizing a transverse magnetic field. | in this study, a series of experiments was conducted to demonstrate the feasibility of continuous production of penicillin antibiotic using a three-phase magneto airlift fermentor with immobilized penicillium chrysogenum. the fermentation processes were carried out in a 2.4-l external loop airlift utilizing a transverse magnetic field. it was found that the application of the magnetic field to a bed of ferromagnetic beads affects both the hydrodynamics of the reactor and the rate of the bioconve ... | 2000 | 10850672 |
| karyotype of penicillium nalgiovense and assignment of the penicillin biosynthetic genes to chromosome iv. | the karyotype of penicillium nalgiovense was determined by pulsed-field gel electrophoresis and compared to the karyotype of p. chrysogenum. both species have four chromosomes, but they differ in the size of the chromosomes and in the overall size of the genome. the sizes of the p. nalgiovense chromosomes as determined by pulsed-field gel electrophoresis are: 9.1 mb, 7.9 mb, 5.4 mb and 4.1 mb which gives in summary a genome size of 26.5 mb. this compares to 34.1 mb for p. chrysogenum. the penici ... | 2000 | 10898462 |
| environmentally safe production of 7-aminodeacetoxycephalosporanic acid (7-adca) using recombinant strains of acremonium chrysogenum. | medically useful semisynthetic cephalosporins are made from 7-aminodeacetoxycephalosporanic acid (7-adca) or 7-aminocephalosporanic acid (7-aca). here we describe a new industrially amenable bioprocess for the production of the important intermediate 7-adca that can replace the expensive and environmentally unfriendly chemical method classically used. the method is based on the disruption and one-step replacement of the cefef gene, encoding the bifunctional expandase/hydroxylase activity, of an ... | 2000 | 10932155 |
| isotopomer analysis using gc-ms. | knowledge of the complete isotopomer distribution represents the ultimate amount of information on the labeling pattern of a metabolite. one technique for measuring the isotopomer distributions is the analysis of the multiplet intensities arising from the 13c-13c couplings in nmr spectroscopy. while this technique has proven to be very valuable in the elucidation of labeling patterns of c2 and c3 units of various amino acids, fragments larger than c3 are very difficult to measure. another techni ... | 1999 | 10937821 |
| overexpression of the lys1 gene in penicillium chrysogenum: homocitrate synthase levels, alpha-aminoadipic acid pool and penicillin production. | homocitrate synthase activity (encoded by the lys1 gene) catalyzes the first step of the lysine and penicillin pathway and is highly sensitive to feedback regulation by l-lysine. the transcript levels of the lys1 gene and the homocitrate synthase activity are high during the growth phase and decrease during the antibiotic production phase, except in the high penicillin producer strain as-p-99 which maintained high levels of homocitrate synthase activity in cultures at 96 h and 120 h. the lys1 ge ... | 2000 | 10952007 |
| induction of positive cooperativity by amino acid replacements within the c-terminal domain of penicillium chrysogenum atp sulfurylase. | atp sulfurylase from penicillium chrysogenum is an allosteric enzyme in which cys-509 is critical for maintaining the r state. cys-509 is located in a c-terminal domain that is 42% identical to the conserved core of adenosine 5'-phosphosulfate (adenylylsulfate) (aps) kinase. this domain is believed to provide the binding site for the allosteric effector, 3'-phosphoadenosine 5'-phosphosulfate (paps). replacement of cys-509 with either tyr or ser destabilizes the r state, resulting in an enzyme th ... | 2000 | 10956658 |
| synthesis and evaluation of some new fluorinated hydroquinazoline derivatives as antifungal agents. | the key intermediate octahydroquinazoline (1) was obtained in one pot synthesis by a modification of the biginelli reaction. compound 1 was allowed to react with phenacyl bromide and bromomalononitrile to furnish thiazolo[2,3-b]quinazoline 3 and 12, respectively. interaction of compound 12 with formamide, formic acid and phenyl isothiocyanate yielded the corresponding pyrimidino[4',5':4.5]thiazolo[2,3-b] quinazolines 13, 14 and 17, respectively. the structure of the synthesized compounds were el ... | 2000 | 10966155 |
| synthesis and antifungal activity of novel pyrano[2',3':4,5]thiazolo[2,3-b]quinazolines, pyrido[2',3':4,5]thiazolo[2,3-b]quinazolines and pyrazolo[2',3':4,5]thiazolo[2,3-b]quinazolines. | the starting materials thiazolo[2,3-b]quinazolines (5a,b) were obtained in one pot synthesis by treating octahydroquinazoline (2) with chloroacetic acid and aromatic aldehydes. thiazoloquinazoline (5) was reacted with ch2(cn)2/piperidine and ch2(cn)2/naoh (ch3oh), to furnish pyrano[2',3':4,5]thiazolo[2,3-b]quinazolines (6a,b) and pyrido[2',3':4,5]thiazolo[2,3-b]quinazoline (7), respectively. refluxing of 5a with nh2csnh2/koh and hydrazines in ethanol furnished the corresponding, [1,3]thiazino[4' ... | 2000 | 10966160 |
| metabolic characterization of high- and low-yielding strains of penicillium chrysogenum. | a recently developed method for analyzing metabolic networks using 13c-labels was employed for investigating the metabolism of a high- and a low-yielding strain of penicillium chrysogenum. under penicillin-producing conditions, the flux through the pentose phosphate (pp) pathway in the high- and the low-yielding strains was estimated to 70 and 66, respectively. when the high-yielding strain was cultivated in a medium without the penicillin side chain precursor, phenoxyacetic acid, the pp pathway ... | 2000 | 10968635 |
| isolation of penicillium chrysogenum pex1 and pex6 encoding aaa proteins involved in peroxisome biogenesis. | in penicillium chrysogenum, key enzymes involved in the production of penicillin reside in peroxisomes. as a first step to understand the role of these organelles in penicillin biosynthesis, we set out to isolate the genes involved in peroxisome biogenesis. here we report the cloning and characterization of p. chrysogenum pex1 and pex6, which encode proteins of the aaa family of atpases. the second aaa module, which is essential for the function of pex1p and pex6p in peroxisome biogenesis, is hi ... | 2000 | 10968639 |
| [a model for the formation of ring-shaped structures in colonies of mycelial fungi]. | mathematical model of the development of the pattern of colonies is considered. the model represents the systems of differential equations of the first order. it includes non-dimensional parameters characterizing the following features: concentration of substrate, concentration of metabolic products--growth inhibitor, mycelium and spores, radial and specific rate of mycelium growth, rate of substrate consumption and production of metabolic products, coefficients of diffusion of substrate and met ... | 2000 | 10999006 |