• Korean Journal of Microbiology
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• v.31 no.2
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• pp.136-140
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• 1993

The A. nidulans expression vector which contained trpC marker gene from A. nidulans was constructed to produce glucoamy]ase. The recombinant plasmid was introduced into auxotrophic mutant A. nidulans B17. Southern blot analysis of the genomic DNA from transformant showed that pKHG2 DNA had integrated into the A. nidulans chromosomes. Northern analysis of the total RNA from transform ant showed that mRNA of glucoamylase gene was synthesized in induction condition. Specific activity of glucoamylase was increased in transform ants. G]ucoamylase was shown to be active in non-denaturing acrylamide gel.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.178-182
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• 2004

In the vegetative hyphae of Aspergillus nidulans, a zymogenic form of the class I chitin synthase activity was successfully measured by the assay condition for Saccharomyces cerevisiae class I chitin synthase, Chsl. The class I chitin synthase activity of the A. nidulans chsC wild type strain was increased about six-fold by trypsin-pretreatment, but that of the chsC disruption strain revealed no increase. Interestingly enough, level of the class I chitin synthase activity of the chsC disruption strain was almost the same as that of the chsC wild type without trypsin-pretreatment. These results indicated that the A. nidulans ChsC activity could be measured by account-ing the class I chitin synthase activity without the trypsin-pretreatment as an internal control. Consistence to the expression pattern of the chsC revealed by northern blot analysis, the activity of ChsC was increased upon reaching the culture time for acquiring developmental competence. Our results shown here also supported the previous report suggesting the possible involvement of ChsC in vegetative hyphal growth of A. nidulans.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1211-1216
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• 2004

A MNNG (N-methyl-N'-nitro-N-nitrosoguanidine) induced chromium resistant strain ($Cr^{r}18$) of unicellular cyanobacterium Anacystis nidulans has been isolated and characterized. The resistant strain could grow (although restricted to $50\%$ of control) in chromium concentration (180${\mu}M$) lethal to the wild-type. Sublethal ($160{\mu}M$) concentration of $Cr^{6+}$ significantly reduced (13-$37.5$) all the photosynthetic pigments of A. nidulans with maximum reduction in phycoerythrin followed by ChI $\alpha$. Pigments of A. nidulans were drastically decreased in lethal concentration of Cr^{6+} with maximum reduction in phycoerythrin ($75\%$) and allophycocyanin ($67.5\%$). Resistant strain $Cr^{r}18$ resisted toxic effects of sublethal and lethal concentrations of $Cr^{6+}$ on photosynthetic pigments as revealed by less decrease in pigments as compared to A. nidulans. Effect of $Cr^{6+}$ stress was also studied on nitrogen assimilation and phosphate uptake. Sublethal concentration of $Cr^{6+}$ drastically reduced ($71.5\%$) nitrate uptake by A. nidulans while a decrease of $29\%$ was observed in strain $Cr^{r}18$. Short (2 day) exposure of A. nidulans and its resistant strain $Cr^{r}18\;to\;Cr^{6+}$ did not affect nitrate reductase and glutamine synthetase (transferase), whereas longer (10 day) exposure to $Cr^{6+}$ lowered activities of both enzymes in A. nidulans but not significantly in the strain $Cr^{r}18$. Ammonium uptake by both strains was not affected by $Cr^{6+}$. Thus, $Cr^{6+}$ affected photosynthetic pigments, nitrogen assimilation, and phosphate uptake of A. nidulans, while strain $Cr^{r}18$ was able to resist toxic effects of the metal. Advantages of using strain $Cr^{r}18$ for bioremediation purposes have been evaluated by studying $Cr^{6+}$ removal from the solution. Resistant strain $Cr^{r}18$ was able to remove $33\%$ more $Cr^{6+}$ than A. nidulans and thus it can prove to be a good candidate for bioremediation of $Cr^{6+}$ from polluted waters.

• Mycobiology
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• v.46 no.4
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• pp.429-439
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• 2018

To develop a convenient promoter analysis system for fungi, a null-pigment mutant (NPG) of Aspergillus nidulans was used with the 4'-phosphopantetheinyl transferase (PPTase) gene, npgA, which restores the normal pigmentation in A. nidulans, as a new reporter gene. The functional organization of serially deleted promoter regions of the A. nidulans trpC gene and the Cryphonectria parasitica crp gene in filamentous fungi was representatively investigated to establish a novel fungal promoter assay system that depends on color complementation of the NPG mutant with the PPTase npgA gene. Several promoter regions of the trpC and crp genes were fused to the npgA gene containing the 1,034-bp open reading frame and the 966-bp 3' downstream region from the TAA, and the constructed fusions were introduced into the NPG mutant in A. nidulans to evaluate color recovery due to the transcriptional activity of the sequence elements. Serial deletion of the trpC and crp promoter regions in this PPTase reporter assay system reaffirmed results in previous reports by using the fungal transformation step without a laborious verification process. This approach suggests a more rapid and convenient system than conventional analyses for fungal gene expression studies.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.312-317
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• 2009

Genome analysis of a model filamentous fungus, Aspergillus nidulans, revealed that there are six putative forkhead genes. Among them, fkhF (AN8949.2) showed A. nidulans-specific. fkhF gene is located in chromosome VII and composed of 2,337 bp coding region for 778 amino acid. Since little is known about the involvement of the forkhead proteins in the developmental process of the filamentous fungi, including A. nidulans, we generated a deletion mutant of fkhF gene and analyzed. Deletion of fkhF resulted in less-dense conidiophore formation in a solid culture. However, the sexual developmental process or cleistothecia formation was normal. Furthermore, fkhF deletion mutant produced conidiophores and conidia under the submerged culture, suggesting that the fkhF gene is involved in repression of inappropriated induction and maturation of asexual developmental process but not in sexual development.

• The Korean Journal of Ecology
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• v.25 no.5
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• pp.353-358
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• 2002

We examined the effect of 12 main monoterpenes in Pinus plants on growth inhibition of Escherichia coli and Aspergillus nidulans. We tested four concentrations of each compound by comparing the clear zone with controls. (R)-(-)carvone, (S)(+)carvone, (1R)(-)fenchone, (-)menthone, α-pinene, (1S) (-)verbenone and (+)β - pinene had a inhibition effect on E. coli. (R)-(-)carvone, (S)(+)carvone, (+) β-pinene, geranyl-acetate, α-pinene, and (1S)(-)verbenone had inhibitory effects on the growth of A. nidulans. Geranyl-acetate inhibit growth of A. nidulans, however not to E. coli. And (1R)(-)fenchone and (-)menthone inhibit growth of E. coli, but not to A. nidulans. Myrcene, sabinene, bornyl acetate, and limonene had no inhibitory effects on E. coli and A. nidulans, eventhough at the highest concentration. All these results suggested that some selected monoterpenes had antifungal activities depend on the species of microorganism.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.39-39
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• 2014

In a homothallic filamentous fungus Aspergillus nidulans, sexual and asexual developments are largely affected by the genetic and environmental factors. To regulate the complex subsets of genes involved in the developmental processes accurately, tight regulations of transcription factors are required. The forkhead type transcription factors are the class of regulators that function in a broad spectrum of cellular and developmental processes in many species from yeast to human. Here, we identified the fkhA and fkhB genes that encode a conserved forkhead transcription factors. The fkhA deletion resulted in the complete loss of fruiting body formation under all conditions favoring sexual development, suggesting that the fkhA gene is required for sexual development in A. nidulans. Overexpression of fkhA resulted in enhanced formation of fruiting bodies under induction condition not only in the normal condition but also in the condition of presence of 0.6 M KCl, which strongly inhibits sexual development. To know the function of the fkhB gene, we also generated fkhB knock-out strain in A. nidulans. Deletion of fkhB resulted in abnormal conidiophore formation under standard conditions and delayed sexual development process, suggesting that the fkhB gene plays an important role in conidiophore morphogenesis Taken together, these results suggest that the fkhA gene is necessary and sufficient for regulating sexual development and the fkhB gene is a transcription factor related in asexual developmental process in A. nidulans.

• Mycobiology
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• v.47 no.4
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• pp.457-465
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• 2019

MonA is a subunit of a guanine nucleotide exchange factor that is important for vacuole passing and autophagy processes in eukaryotes. In this study, we characterized the function of MonA, an orthologue of Saccharomyces cerevisiae Mon1, in the model fungus Aspergillus nidulans and a toxigenic fungus A. flavus. In A. nidulans, the absence of AnimonA led to decreased fungal growth, reduced asexual reproduction, and defective cleistothecia production. In addition, AnimonA deletion mutants exhibited decreased spore viability, had reduced trehalose contents in conidia, and were sensitive to thermal stress. In A. flavus, deletion of AflmonA caused decreased fungal growth and defective production of asexual spores and sclerotia structures. Moreover, the absence of monA affected vacuole morphology in both species. Taken together, these results indicate that MonA plays conserved roles in controlling fungal growth, development and vacuole morphology in A. nidulans and A. flavus.

• Mycobiology
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• v.37 no.3
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• pp.171-182
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• 2009

Many aspergilli that belongs to ascomycetes have sexuality. In a homothallic or self-fertile fungus, a number of fruiting bodies or cleistothecia are formed in a thallus grown from a single haploid conidia or ascospores. Genome-sequencing project revealed that two mating genes (MAT) encoding the regulatory proteins that are necessary for controlling partner recognition in heterothallic fungi were conserved in most aspergilli. The MAT gene products in some self-fertile species were not required for recognition of mating partner at pheromone-signaling stage but required at later stages of sexual development. Various environmental factors such as nutritional status, culture conditions and several stresses, influence the decision or progression of sexual reproduction. A large number of genes are expected to be involved in sexual development of Emericella nidulans (anamorph: Aspergillus nidulans), a genetic and biological model organism in aspergilli. The sexual development process can be grouped into several development stages, including the decision of sexual reproductive cycle, mating process, growth of fruiting body, karyogamy followed by meiosis, and sporulation process. Complicated regulatory networks, such as signal transduction pathways and gene expression controls, may work in each stage and stage-to-stage linkages. In this review, the components joining in the regulatory pathways of sexual development, although they constitute only a small part of the whole regulatory networks, are briefly mentioned. Some of them control sexual development positively and some do negatively. Regarding the difficulties for studying sexual differentiation compare to asexual one, recent progresses in molecular genetics of E. nidulans enlarge the boundaries of understanding sexual development in the non-fertile species as well as in fertile fungi.

• Mycobiology
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• v.49 no.3
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• pp.258-266
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• 2021

The velvet regulators VosA and VelB are primarily involved in spore maturation and dormancy. Previous studies found that the VosA-VelB hetero-complex coordinates certain target genes that are related to fungal differentiation and conidial maturation in Aspergillus nidulans. Here, we characterized the VosA/VelB-inhibited developmental gene vidD in A. nidulans. Phenotypic analyses demonstrated that the vidD deleted mutant exhibited defect fungal growth, a reduced number of conidia, and delayed formation of sexual fruiting bodies. The deletion of vidD decreased the amount of conidial trehalose, increased the sensitivity against heat stress, and reduced the conidial viability. Moreover, the absence of vidD resulted in increased production of sterigmatocystin. Together, these results show that VidD is required for proper fungal growth, development, and sterigmatocystin production in A. nidulans.