Search results for "Aspergillus Nidulans"
showing 10 items of 13 documents
Crowdsourced analysis of fungal growth and branching on microfluidic platforms
2021
Fungal hyphal growth and branching are essential traits that allow fungi to spread and proliferate in many environments. This sustained growth is essential for a myriad of applications in health, agriculture, and industry. However, comparisons between different fungi are difficult in the absence of standardized metrics. Here, we used a microfluidic device featuring four different maze patterns to compare the growth velocity and branching frequency of fourteen filamentous fungi. These measurements result from the collective work of several labs in the form of a competition named the “Fungus Olympics.” The competing fungi included five ascomycete species (ten strains total), two basidiomycete…
Transformation of Aspergillus parasiticus using autonomously replicating plasmids from Aspergillus nidulans.
1994
A genetic transformation system for the aflatoxin-producing fungus Aspergillus parasiticus using two autonomously replicating plasmids from A. nidulans (ARp1 and pDHG25) is reported. Transformation frequencies using the plasmid pDHG25 were from 5 x 10(2) to 2.5 x 10(4) transformants per 10(6) viable protoplasts and microgram DNA. The stability of the plasmids in the transformants was also studied. This transformation system offers a new opportunity to clone genes related to aflatoxin production using appropriate aflatoxin-defective mutants.
Identification of the mstE Gene Encoding a Glucose-inducible, Low Affinity Glucose Transporter in Aspergillus nidulans
2006
The mstE gene encoding a low affinity glucose transporter active during the germination of Aspergillus nidulans conidia on glucose medium has been identified. mstE expression also occurs in hyphae, is induced in the presence of other repressing carbon sources besides glucose, and is dependent on the function of the transcriptional repressor CreA. The expression of MstE and its subcellular distribution have been studied using a MstE-sGFP fusion protein. Concordant with data on mstE expression, MstE-sGFP is synthesized in the presence of repressing carbon sources, and fluorescence at the periphery of conidia and hyphae is consistent with MstE location in the plasma membrane. Deletion of mstE …
pH control of the production of recombinant glucose oxidase in Aspergillus nidulans.
2004
Aims: Recombinant Aspergillus nidulans sVAL040, capable of synthesizing and secreting glucose oxidase derived from Aspergillus niger was used to study the influence of pH and carbon source on enzyme production. Methods and Results: Glucose oxidase gene (goxC) was expressed under transcriptional regulation by using the promoter of A. nidulans xlnB gene (encoding an acidic xylanase). A maximum specific glucose oxidase activity of approx. 10 U mg−1 protein and a maximum volumetric productivity of 29·9 U l−1 h−1 were obtained at pH 5·5, after 80 h of growth by using xylose as inducer. Enzyme volumetric productivity increased when xylans were used instead of xylose; however, specific glucose o…
Sequences of isopenicillin N synthetase genes suggest horizontal gene transfer from prokaryotes to eukaryotes
1990
Evolutionary distances between bacterial and fungal isopenicillin N synthetase (IPNS) genes have been compared to distances between the corresponding 5S rRNA genes. The presence of sequences homologous to the IPNS gene has been examined in DNAs from representative prokaryotic organisms and Ascomycotina. The results of both analyses strongly support two different events of horizontal transfer of the IPNS gene from bacteria to filamentous fungi. This is the first example of such a type of transfer from prokaryotes to eukaryotes.
Complementation among developmental mutants in Aspergillus nidulans.
1973
In heterokaryons between pairs of aconidial mutants of Aspergillus nidulans one of the component strains usually shows a striking prevalance in the contribution to the conidial crop. By assuming that the prevailing strain is blocked earlier and the succumbent one later in the process of differentiation, a series of mutations can be arranged in a consistent order. Some mutant strains do not fit the scheme exactly but show a general tendency to be succumbent to “early” mutants and prevalent over the “late” ones. A criterion for arraying genes involved in differentiation according to the order of their physiological action is proposed.
Interaction of Human Phagocytes with Pigmentless Aspergillus Conidia
2000
ABSTRACT A defect in the pksP gene of Aspergillus fumigatus is associated with the loss of conidial pigmentation, a profound change of the conidial surface structure, and reduced virulence. The structural change of the conidial surface structure was not observed in similar A. nidulans wA mutants. Our data indicate that the pigment of both species is important for scavenging reactive oxygen species and for protection of conidia against oxidative damage.
Discovery of an Extended Austinoid Biosynthetic Pathway in Aspergillus calidoustus
2017
Filamentous fungi produce a wide range of natural products that are commonly used in various industrial contexts (e.g., pharmaceuticals and insecticides). Meroterpenoids are natural products of interest because of their various biological activities. Among the meroterpenoids, there is a group of insecticidal compounds known as the austinoids. These compounds have also been studied because of their intriguing spiro-lactone ring formation along with various modifications. Here, we present an extension of the original austinol/dehydroaustinol biosynthesis pathway from Aspergillus nidulans in the recently identified filamentous fungus Aspergillus calidoustus. Besides the discovery and elucidati…
Toxicological Assessment of Recombinant Xylanase X22 in Wine
1999
Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wi…
Phylogenetic analysis of the isopenicillin-N-synthetase horizontal gene transfer.
1996
A phylogenetic study of the isopenicillin-N-synthetase (IPNS) gene sequence from prokaryotic and lower eukaryotic producers of beta-lactam antibiotics by means of a maximum-likelihood approach has been carried out. After performing an extensive search, rather than invoking a global molecular clock, the results obtained are best explained by a model with three rates of evolution. Grouped in decreasing order, these correspond to A. nidulans and then to the rest of the eukaryotes and prokaryotes, respectively. The estimated branching date between prokaryotic and fungal IPNS sequences (852 +/- 106 MY) strongly supports the hypothesis that the IPNS gene was horizontally transferred from bacteria…