Aspergillus Cristatus Research Articles

Modulation of gut homeostasis by exopolysaccharides from Aspergillus cristatus (MK346334), a strain of fungus isolated from Fuzhuan brick tea, contributes to immunomodulatory activity in cyclophosphamide-treated mice.

In this study, the crude exopolysaccharides (CEPSs) from fungus Aspergillus cristatus (MK346334, NCBI) isolated from Fuzhuan brick tea and its main purified fraction (EPSs-2) were investigated. Using the RAW264.7 cell model, EPSs-2 exhibited an excellent immunomodulatory effect in vitro. Then, the regulating effects of EPSs on immune function and gut microbiota were evaluated using a cyclophosphamide (Cy)-induced mice model. It was found that both CEPSs and EPSs-2 improved the body weight loss, immune organ indexes as well as the levels of TNF-α, IL-1β, IFN-γ and IgA, exhibiting potent immunoregulatory activity. Moreover, CEPSs and EPSs-2 not only attenuated the intestinal tissue damage, but also promoted the production of short-chain fatty acids and modulated the microbial composition by increasing the growth of Muribaculaceae, Prevotellaceae_UCG-001, Bacteroides, Parabacteroides and Tidjanibacter, while decreasing the relative abundances of Helicobacter, Bilophila, Mucispirillum, Lachnospiraceae, Ruminococcaceae and Clostridiales. These results indicated that the EPSs, especially EPSs-2, exhibited immunomodulatory activity associated with the modulation of gut microbiota to maintain gut homeostasis, which provided evidence for the development of novel potential prebiotics and immunomodulators.

Simulated digestion and fermentation in vitro by human gut microbiota of intra- and extra-cellular polysaccharides from Aspergillus cristatus

Fuzhuan brick tea is characterized in unique “golden flower” of Aspergillus cristatus. However, little information is available for intra- and extra-cellular polysaccharides from A. cristatus (IPS and EPS, respectively). Therefore, simulated digestion and fermentation in vitro were carried out to investigate whether IPS and EPS could be broken down in digestive system. Furthermore, their interactions with gut microbiota were investigated. It was found that IPS and EPS were utilized by gut microbiota to metabolize into short-chain fatty acids (SCFAs). The contents of total acids (SCFAs and lactic acid) in IPS and EPS groups increased to 39.30 ± 0.66 and 45.18 ± 1.68 mmol/L, respectively. IPS and EPS could obviously modulate the composition of gut microbiota. Thereinto, IPS could maintain the growth of OTU26 and OTU69 (Prevotella) and increase the relative levels of OTU30, OTU31, OTU35 and OTU56 (Bacteroides), whereas, EPS could maintain the growth of OTU26 and OTU48 (Prevotella) and increase the relative levels of OTU35, OTU56 and OTU63 (Bacteroides). OTU26, OTU61 and OTU69 (Prevotella) showed significantly positive correlations with propionic acid, OTU48 (Prevotella) and OTU56 (Bacteroides) showed significantly positive correlations with acetic acid. Hence, IPS and EPS could regulate the composition of gut microbiota, thereby promote production of SCFAs.

Recycling of Chinese herb residues by endophytic and probiotic fungus Aspergillus cristatus CB10002 for the production of medicinal valuable anthraquinones

BackgroundThe global prevalence of traditional Chinese medicine stimulates the prosperous development of herb medicines, but the annual generation of massive herb residues becomes big issues about environmental pollution and waste of resources. Microbes play important roles in the circulation of substances in nature, and endophytes represent an underexplored microbial resource possessing the unique symbiotic relationship with plants, not only for discovery of secondary metabolites, but also for potential green recycling of herb residues.ResultsThe recycling capacities of several endophytic strains were respectively evaluated via solid state fermentation with herb residues of commercial Huazhenghuisheng oral-liquid (HOL). Among them, Aspergillus cristatus CB10002, a probiotic fungus isolated from Chinese Fu-brick tea, was competent to recycle HOL residues for the production of medicinal valuable anthraquinones, in which four of them, especially citreorosein with significant anti-obesity activity, were first discovered in A. cristatus. Subsequent quantitative analysis showed that about 2.0 mg/g citreorosein and 7.5 mg/g total anthraquinones could be obtained after 35-day fermentation, which was very competitive and economically beneficial. Further nutritional comparisons also revealed that the recycling process indeed ameliorated the nutrients of HOL residues, and thus proposed a possibility to directly dispose the final leftovers as a compost organic fertilizer.ConclusionsThe endophytic and probiotic fungus A. cristatus CB10002 isolated from Chinese Fu-brick tea was screened out to effectively reutilize HOL residues for the production of nine medicinal valuable anthraquinones, whose biosynthesis may be regulated by the induction of HOL residues. The competitive yields of these anthraquinones, as well as the certain composting properties of final leftovers, have made the microbial recycling of HOL residues economically beneficial. Our work demonstrated a promising applied potential of A. cristatus in reutilization of herb residues, and provided a practical strategy for sustainable and value-added microbial recycling of herb residues.

Analysis of bacterial and fungal communities by Illumina MiSeq platforms and characterization of Aspergillus cristatus in Fuzhuan brick tea

Fuzhuan brick tea (FBT) is an indigenous dark tea fermented by fungal and bacterial communities, and the special favor of FBT attributes to the actions of microbiota, while the correlation between bacteria and fungi attracts little attention. In the present study, therefore, the compositions of microbial communities in 10 samples of FBT from four tea processing factories were evaluated by Illumina MiSeq sequencing. Bacterial taxonomy analysis revealed that the phylum Firmicutes and Proteobacteria were the predominant bacteria in all samples. Fungal taxonomy analysis revealed that the phylum Ascomycota, family Trichocomaceae, genus Aspergillus was the dominant fungus in all samples. Moreover, Aspergillus (OTU1, OTU2, OTU16, OTU30, OTU31 and OTU37), Wallemia (OTU3), Penicillium (OTU32), Candida (OTU33, OTU35, OTU40 and OTU43), Debaryomyces (OTU48) and Rhodotorula (OTU68) showed higher correlation with bacteria in FBT. Furthermore, a strain Aspergillus cristatus was isolated from FBT, and its morphology and molecular taxonomy were observed and analyzed by scanning electron microscopy and sequencing. Hence, this is the first report to reveal the correlation between bacterial and fungal communities in FBT, and A. cristatus may have potential application to improve the quality of FBT.

Genetic Basis and Function of Mating-Type Genes in Aspergillus cristatus

Genetic Basis and Function of Mating-Type Genes in Aspergillus cristatus

Comparative proteomic analysis reveals the regulatory network of the veA gene during asexual and sexual spore development of Aspergillus cristatus.

Aspergillus cristatus is the predominant fungal population during fermentation of Chinese Fuzhuan brick tea, and belongs to the homothallic fungal group that undergoes a sexual stage without asexual conidiation under hypotonic conditions, while hypertonic medium induces initiation of the asexual stage and completely blocks sexual development. However, the veA deletion mutant only produces conidia in hypotonic medium after a 24-h culture, but both asexual and sexual spores are observed after 72 h. The veA gene is one of the key genes that positively regulates sexual and negatively regulates asexual development in A. cristatus. To elucidate the molecular mechanism of how VeA regulates asexual and sexual spore development in A. cristatus, 2D electrophoresis (2-DE) combined with MALDI-tandem ToF MS analysis were applied to identify 173 differentially expressed proteins (DEPs) by comparing the agamotype (24 h) and teleomorph (72 h) with wild-type (WT) A. cristatus strains. Further analysis revealed that the changed expression pattern of Pmk1-MAPK and Ser/Thr phosphatase signaling, heat shock protein (Hsp) 90 (HSP90), protein degradation associated, sulphur-containing amino acid biosynthesis associated, valine, leucine, isoleucine, and arginine biosynthesis involved, CYP450 and cytoskeletal formation associated proteins were involved in the production of conidia in agamotype of A. cristatus. Furthermore, the deletion of veA in A. cristatus resulted in disturbed process of transcription, translation, protein folding, amino acid metabolism, and secondary metabolism. The carbohydrate and energy metabolism were also greatly changed, which lied in the suppression of anabolism through pentose phosphate pathway (PPP) but promotion of catabolism through glycolysis and tricarboxylic acid (TCA) cycle. The energy compounds produced in the agamotype were mainly ATP and NADH, whereas they were NADPH and FAD in the teleomorph. These results will contribute to the existing knowledge on the complex role of VeA in the regulation of spore development in Aspergillus and provide a framework for functional investigations on the identified proteins.

The role of the veA gene in adjusting developmental balance and environmental stress response in Aspergillus cristatus

veA belongs to the velvet regulatory system that regulates the development and secondary metabolism of many fungi. To identify the function of veA in Aspergillus cristatus, veA deletion mutants were constructed by homologous recombination via Agrobacterium tumefaciens-mediated transformation. Deletion of veA led to increased conidial production and reduced sexual sporulation. The regulatory role of veA in A. cristatus was not light-dependent, and this differed from its role in other Aspergilli. Furthermore, veA deletion mutants were more sensitive to environmental stressors, including salt, osmotic pressure, temperature and pH. In contrast, deletion of veA resulted in increased resistance to oxidative stress. veA also affected aerial vegetative growth. Transcriptomic analysis of the veA-null mutant and wild type indicated that most asexual and sexual development genes were upregulated and downregulated, respectively. These findings confirmed that veA has a positive effect on sexual development but represses conidial formation. Overall, these results suggested that the veA gene plays a critical role in maintaining a developmental balance between asexual and sexual sporulation and is involved in vegetative growth and environmental stress response in A. cristatus.

Metabolomics reveals changes in metabolite concentrations and correlations during sexual development of Eurotium cristatum (synonym: Aspergillus cristatus)

Metabolomics reveals changes in metabolite concentrations and correlations during sexual development of Eurotium cristatum (synonym: Aspergillus cristatus)

Comparative genomic and transcriptomic analyses of the Fuzhuan brick tea-fermentation fungus Aspergillus cristatus.

BackgroundAspergillus cristatus is the dominant fungus involved in the fermentation of Chinese Fuzhuan brick tea. Aspergillus cristatus is a homothallic fungus that undergoes a sexual stage without asexual conidiation when cultured in hypotonic medium. The asexual stage is induced by a high salt concentration, which completely inhibits sexual development. The taxon is therefore appropriate for investigating the mechanisms of asexual and sexual reproduction in fungi. In this study, de novo genome sequencing and analysis of transcriptomes during culture under high- and low-osmolarity conditions were performed. These analyses facilitated investigation of the evolution of mating-type genes, which determine the mode of sexual reproduction, in A. cristatus, the response of the high-osmolarity glycerol (HOG) pathway to osmotic stimulation, and the detection of mycotoxins and evaluation of the relationship with the location of the encoding genes.ResultsThe A. cristatus genome comprised 27.9 Mb and included 68 scaffolds, from which 10,136 protein-coding gene models were predicted. A phylogenetic analysis suggested a considerable phylogenetic distance between A. cristatus and A. nidulans. Comparison of the mating-type gene loci among Aspergillus species indicated that the mode in A. cristatus differs from those in other Aspergillus species. The components of the HOG pathway were conserved in the genome of A. cristatus. Differential gene expression analysis in A. cristatus using RNA-Seq demonstrated that the expression of most genes in the HOG pathway was unaffected by osmotic pressure. No gene clusters associated with the production of carcinogens were detected.ConclusionsA model of the mating-type locus in A. cristatus is reported for the first time. Aspergillus cristatus has evolved various mechanisms to cope with high osmotic stress. As a fungus associated with Fuzhuan tea, it is considered to be safe under low- and high-osmolarity conditions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2637-y) contains supplementary material, which is available to authorized users.

Monitoring the mycobiota of three plants manufacturing Culatello (a typical Italian meat product)

This study reports the composition of the mycobiota growing on the surface of Culatello (a typical Italian meat product) and occurring in the environments of three processing plants. Samples were collected in both winter and summer. A total of 84 culatelli and 14 samples from the plant environment were examined. A total of 331 (from food samples) and 2030 (from air samples) fungal isolates belonging to six genera and 29 species were identified. The substantial correspondence between air- and product-mycobiota in all the manufacturing plants studied seems to indicate a natural selection of those species that have adapted to the thermal–hygrometric conditions to which meat products were subjected. In particular, all sexual Aspergillus spp. with Eurotium-type ascomata, all Scopulariopsis spp. and Sporendonema casei from culatelli exactly matched with those from air samplings, and a prevalence of xerotolerant and xerophilic species belonging to Aspergillus or Penicillium was observed for both culatelli and environments, depending on the plant considered. Aspergillus candidus (16.0%), Penicillium solitum (19.6%), and Aspergillus cristatus (≡ Eurotium cristatum) (17.2%) were the prevalent species in Plants 1, 2, and 3, respectively. Fungal species producing unsightly spots on the casings (Scopulariopsis spp. and Sporendonema casei) were mainly found in the first steps of the aging, but tended to diminish or to change color throughout the process, so ultimately they did not represent a matter of concern. Fungal species potentially producing ochratoxin A (Penicillium nordicum and Aspergillus westerdijkiae) were the least prevalent species collected from a minor number of culatelli, so their presence could be defined as sporadic and did not represent a risk for consumers' health. This study reports the dominance of desirable species over undesirable molds on culatelli, but also highlights the importance of monitoring those meat products where no bacterial starter can degrade mycotoxins and where neither fungal starters nor a skin can inhibit fungal development. The control of the so-called “house mycobiota” in such products should be periodically assessed both in artisanal and industrial plants, since it proved to be fundamental to focus the potential risks connected to consumption of these meat products.

Biosorption of Cadmium from Aqueous Solutions Using A local Fungus Aspergillus cristatus (Glaucus Group)

Cadmium (Cd) (II) resistant strain of a marine fungus, named Aspergillus cristatus was isolated from heavy metals polluted area in the Mediterranean Sea, Alexandria, Egypt during autumn, 2009. It could tolerate up to 100 mg l –1 . Optimization of culture conditions for production of fungal biomass fortifying maximum Cd (II) removal was done by applying Placket Burman experimental design. Under optimized culture conditions, metal uptake was (82%) achieved in a medium predicted to contain (gl -1 ): glucose, 5; yeast extract, 1; KH 2 PO 4 , 4.00; (NH 4 ) 2 SO 4 , 4; MgSO 4 , 0.75; CaCl 2 .H 2 O, 0.2 and inoculums size, 6%. A verification experiment was applied. Results show that the metal uptake increased by about 1.86 fold for optimized medium. The increase in the pH value from 3 to 6 led to an increase in the Cd (II) uptake which reached the maximum level at pH 6. The biosorption equilibrium time was 4 h. Sorption isotherms follow the typical Langmuir adsorption pattern. Living biomass was more efficient for Cd (II) uptake compared to its dried biomass. A successful trial showed good applicability of the marine fungal isolate to remove 98.1% of Cd (II), in the waste effluent of El- Nesr Varta Company for Batteries after 2 h of contact. The free living fungus succeeds to remove Cd (II) more than the luffa adsorbed fungal biomass from the waste effluent. These quantitative biosorption and accumulation capacities demonstrate the potential application of marine A. cristatus for the bioremediation of Cd (II) from water systems. Key words : Aspergillus cristatus , cadmium, experimental design.