Aspergillus niger as a Secondary Metabolite Factory

Effect of Plasma-Activated Water on the Cellulase-Producing Strain Aspergillus niger A32

To investigate the effect and mechanism of plasma-activated water (PAW) on Aspergillus niger, PAW was prepared using a needle array-plate dielectric barrier discharge plasma system. The concentrations of long-lived reactive oxygen and nitrogen species (RONS), namely, H2O2, NO2-, and NO3-, in the PAW were 48.76 mg/L, 0.046 mg/L, and 172.36 mg/L, respectively. Chemically activated water (CAW) with the same concentration of long-lived RONS was also prepared for comparison. A. niger A32 was treated with PAW and CAW. After treatment, the treated strains were observed and analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to screen probable mutants. The results indicated that the pH, conductivity, and ORP values of PAW were 2.42, 1935 μS/cm, and 517.07 mV, respectively. In contrast, the pH and ORP values of CAW were 6.15 and 301.73 mV, respectively, which differed significantly from those of PAW. In addition, the conductivity of CAW showed no change. SEM and TEM analyses revealed that A. niger A32 treated with CAW exhibited less damage compared with the control. In contrast, A. niger A32 treated with PAW showed significant shrinkage, deformation, and exudate attachment over time. Following PAW treatment, after four passages, a high cellulase-producing stable mutant strain A-WW5 was screened, exhibiting a filter paper enzyme activity of 29.66 U/mL, a cellulose endonuclease activity of 13.79 U/mL, and a β-glucosidase activity of 27.13 U/mL. These values were found to be 33%, 38%, and 2.1% higher than those of the original fungus sample, respectively. In total, 116 SNPs and 61 InDels were present in the genome of the mutant strain A-WW5. The above findings indicate that the impact of PAW on A. niger is not only attributed to long-lasting H2O2, NO2-, and NO3- particles but also to other short-lived active particles; PAW is expected to become a new microbial breeding mutagen.

Involvement of LaeA and Velvet Proteins in Regulating the Production of Mycotoxins and Other Fungal Secondary Metabolites

Fungi are rich sources of secondary metabolites of agrochemical, pharmaceutical, and food importance, such as mycotoxins, antibiotics, and antitumor agents. Secondary metabolites play vital roles in fungal pathogenesis, growth and development, oxidative status modulation, and adaptation/resistance to various environmental stresses. LaeA contains an S-adenosylmethionine binding site and displays methyltransferase activity. The members of velvet proteins include VeA, VelB, VelC, VelD and VosA for each member with a velvet domain. LaeA and velvet proteins can form multimeric complexes such as VosA-VelB and VelB-VeA-LaeA. They belong to global regulators and are mainly impacted by light. One of their most important functions is to regulate gene expressions that are responsible for secondary metabolite biosynthesis. The aim of this mini-review is to represent the newest cognition of the biosynthetic regulation of mycotoxins and other fungal secondary metabolites by LaeA and velvet proteins. In most cases, LaeA and velvet proteins positively regulate production of fungal secondary metabolites. The regulated fungal species mainly belong to the toxigenic fungi from the genera of Alternaria, Aspergillus, Botrytis, Fusarium, Magnaporthe, Monascus, and Penicillium for the production of mycotoxins. We can control secondary metabolite production to inhibit the production of harmful mycotoxins while promoting the production of useful metabolites by global regulation of LaeA and velvet proteins in fungi. Furthermore, the regulation by LaeA and velvet proteins should be a practical strategy in activating silent biosynthetic gene clusters (BGCs) in fungi to obtain previously undiscovered metabolites.

Screening and identification of an aflatoxin B1-degrading strain from the Qinghai-Tibet Plateau and biodegradation products analysis

This research aimed to address the issue of aflatoxin B1 (AFB1) contamination, which posed severe health and economic consequences. This study involved exploring unique species resources in the Qinghai-Tibet Plateau, screening strains capable of degrading AFB1. UPLC-Q-Orbitrap HRMS and NMR were employed to examine the degradation process and identify the structure of the degradation products. Results showed that Bacillus amyloliquefaciens YUAD7, isolated from yak dung in the Qinghai-Tibet Plateau, removed 91.7% of AFB1 from TSB-AFB1 medium with an AFB1 concentration of 10 μg/mL (72 h, 37°C, pH 6.8) and over 85% of AFB1 from real food samples at 10 μg/g (72 h, 37°C), exhibiting strong AFB1 degradation activity. Bacillus amyloliquefaciens YUAD7's extracellular secretions played a major role in AFB1 degradation mediated and could still degrade AFB1 by 43.16% after boiling for 20 min. Moreover, B. amyloliquefaciens YUAD7 demonstrated the capability to decompose AFB1 through processes such as hydrogenation, enzyme modification, and the elimination of the -CO group, resulting in the formation of smaller non-toxic molecules. Identified products include C12H14O4, C5H12N2O2, C10H14O2, C4H12N2O, with a structure consisting of dimethoxyphenyl and enoic acid, dimethyl-amino and ethyl carbamate, polyunsaturated fatty acid, and aminomethyl. The results indicated that B. amyloliquefaciens YUAD7 could be a potentially valuable strain for industrial-scale biodegradation of AFB1 and providing technical support and new perspectives for research on biodegradation products.

Establishing a one-step marker-free CRISPR/Cas9 system for industrial Aspergillus niger using counter-selectable marker Ang-ace2

OBJECTIVES

To develop a one-step, marker-free CRISPR/Cas9 system for highly efficient genome editing in industrial Aspergillus niger, with a short genetic operation cycle.

RESULTS

Firstly, evaluation of different promoters for sgRNA expression revealed tRNAGly15 as the most efficient, achieving a remarkable 100% gene editing efficiency. Furthermore, a counter-selectable marker, Ang-ace2, was identified for A. niger. Subsequently, a CRISPR/Cas9 plasmid was developed, utilizing a truncated AMA1 element and the Ang-ace2 conditional expression cassette driven by a Tet-on promoter. In the presence of doxycycline, the plasmid demonstrated a 33% loss efficiency in the progeny of A. niger spores after a single generation, resulting in a shortened genetic operation cycle of 16 days for CRISPR/Cas9.

CONCLUSIONS

The one-step marker-free CRISPR/Cas9 system was successfully developed in industrial A. niger, allowing for efficient gene editing while simultaneously reducing the editing time.

Pharmacological activities of chemically characterized essential oils from Haplophyllum tuberculatum (Forssk.)

The present work aimed at characterizing the phytochemical composition of Haplophyllum tuberculatum essential oil (HTEO), assessing its antifungal activity against various fungal strains, evaluating its insecticidal and repulsive properties against Callosobruchus maculatus, and determine its antioxidant capacity. To this end, Gas chromatography-mass spectrometry analysis detected 34 compounds in HTEO, with β-Caryophyllene being the major constituent (36.94%). HTEO demonstrated predominantly modest antifungal effects, however, it sustains notable activity, particularly against Aspergillus flavus, with an inhibition rate of 76.50% ± 0.60%. Minimum inhibitory concentrations ranged from 20.53 ± 5.08 to 76.26 ± 5.08 mg/mL, effectively inhibiting fungal growth. Furthermore, the antifungal, and antioxidant activities of HTEO were evaluated in silico against the proteins Aspergillus flavus FAD glucose dehydrogenase, and beta-1,4-endoglucanase from Aspergillus niger, NAD(P)H Oxidase. Moreover, HTEO displayed strong insecticidal activity against C. maculatus, with contact and inhalation tests yielding LC50 values of 30.66 and 40.28 μL/100g, respectively, after 24 h of exposure. A dose of 5 μL/100g significantly reduced oviposition (48.85%) and inhibited emergence (45.15%) compared to the control group. Additionally, HTEO exhibited a high total antioxidant capacity of 758.34 mg AAE/g EO, highlighting its antioxidant potential. Insilico results showed that the antifungal activity of HTEO is mostly attributed to γ-Cadinene and p-Cymen-7-ol, while antioxidant is attributed to α-Terpinyl isobutyrate displayed. Overall, HTEO offers a sustainable and environmentally friendly alternative to synthetic products used to manage diseases.

Aspergillus niger CJ6 extract with antimicrobial potential promotes in-vitro cytotoxicity and induced apoptosis against MIA PaCa-2 cell line

Nowadays, the increased number of multidrug-resistant strains among pathogens is a severe public health concern and cancer is posing a great threat for humans. These problems should be tackled with the development of novel and broad-spectrum antimicrobials from microbial origin. During the present study, the bioactive secondary metabolites from Aspergillus niger CJ6 were extracted, characterized; their biological properties were evaluated by subjecting them for antimicrobial, antifungal and anticancer activities. The potent isolate Aspergillus niger CJ6 with nucleotide sequence of 959 base pairs showed antagonistic activity against fungal pathogens in dual culture. The chemical profiling of crude ethyl acetate extract indicated the presence of various bioactive molecules belonging to phenolic, hydrocarbons, and phthalate derivative classes. In antimicrobial activity, the crude extract displayed increasing activity with increased concentration; the highest activity observed against Shigella flexneri with 15 ± 1.0, 19 ± 0.5, 20 ± 1.0 and 24 ± 1.0 mm zones of inhibition at 25, 50, 75 and 100 μl concentrations. The MTT assay illustrated deformed cells of MIA PaCa-2 cell line in in-vitro cytotoxic activity; outflow of cell matrix and membrane rupture; the IC₅₀ of 90.78 μg/ml suggested moderate potential of extract to prevent cancer cell growth. The apoptosis/necrosis study by flow cytometer exhibited 8.98 ± 0.85% early and 73 ± 0.7% of late apoptotic population with 3.8 ± 1.1% necrotic cells; only 14.22 ± 0.6% of healthy cells suggested the increased apoptosis inducing capacity of Aspergillus niger CJ6 crude extract. The outcomes of this study persuade further exploration on the identification, purification and development of novel bioactive agents that could help battle fatal diseases in humans.

Cell-free synthesis of silver nanoparticles in spent media of different Aspergillus species

The recovery and valorization of metals and rare earth metals from wastewater are of great importance to prevent environmental pollution and recover valuable resources. Certain bacterial and fungal species are capable of removing metal ions from the environment by facilitating their reduction and precipitation. Even though the phenomenon is well documented, little is known about the mechanism. Therefore, we systematically investigated the influence of nitrogen sources, cultivation time, biomass, and protein concentration on silver reduction capacities of cell-free cultivation media (spent media) of Aspergillus niger, A. terreus, and A. oryzae. The spent medium of A. niger showed the highest silver reduction capacities with up to 15 μmol per milliliter spent medium when ammonium was used as the sole N-source. Silver ion reduction in the spent medium was not driven by enzymes and did not correlate with biomass concentration. Nearly full reduction capacity was reached after 2 days of incubation, long before the cessation of growth and onset of the stationary phase. The size of silver nanoparticles formed in the spent medium of A. niger was influenced by the nitrogen source, with silver nanoparticles formed in nitrate or ammonium-containing medium having an average diameter of 32 and 6 nm, respectively.

Polyketides as Secondary Metabolites from the Genus Aspergillus

Polyketides are an important class of structurally diverse natural products derived from a precursor molecule consisting of a chain of alternating ketone and methylene groups. These compounds have attracted the worldwide attention of pharmaceutical researchers since they are endowed with a wide array of biological properties. As one of the most common filamentous fungi in nature, Aspergillus spp. is well known as an excellent producer of polyketide compounds with therapeutic potential. By extensive literature search and data analysis, this review comprehensively summarizes Aspergillus-derived polyketides for the first time, regarding their occurrences, chemical structures and bioactivities as well as biosynthetic logics.

Electron microscopic imaging and NanoSIMS investigation on physiological responses of Aspergillus niger under Pb(II) and Cd(II) stress

In the bioremediation process, coexistence of lead (Pb) and cadmium causes complex toxicity, resulting in the difficulty of bioremediation. This study investigated the physiological responses and bioaccumulation mechanisms of the typical filamentous fungus Aspergillus niger under the coexistence of Pb and Cd. Four treatments were set up, i.e., control, sole Pb, sole Cd, and coexistence of Pb and Cd. The morphology of A. niger were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Then, nano-scale secondary ion mass spectrometry (NanoSIMS) was applied to accurately investigate the distribution of heavy metals in the fungal cells under the coexistence of Pb and Cd. Finally, the metallogenic process and mineral types were simulated by Geochemist's Workbench (GWB). The electron microscopic and NanoSIMS imaging showed that Pb and Cd were accumulated in both the extracellular and intracellular regions of the A. niger cells. In particular, the accumulated Pb content was ten times higher than that of Cd. However, Cd showed stronger toxicity than Pb to A. niger. Compared with the control treatment, Cd stress resulted in a two-fold increase of cell diameter and more extracellular substances, whereas the cell diameter increased nearly four times in the coexistence treatment. Moreover, the bioaccumulation of Pb was more intense than that of Cd during competitive sorption. The GWB simulation confirmed that Pb²⁺ can form multiple minerals (e.g., PbC₂O₄, PbHPO₄, and Pb₃(PO₄)₂, etc.), which significantly weakened its toxicity on the cell surface. This study elucidated the morphological characteristics of A. niger and competitive bioaccumulation under the coexistence of Pb and Cd, which would facilitate the application of microorganisms to the bioremediation of coexisted metals.

Effects of Aspergillus niger on cyanogenic glycosides removal and fermentation qualities of ratooning sorghum

Introduction

Cyanogenic glycosides (CNglcs) are bioactive plant products involving in plant defense against herbivores by virtue of their abilities to release toxic hydrogen cyanide (HCN). Aspergillus niger has been shown to be effective in producing β-glucosidase, which could degrade CNglcs. However, whether A. niger could remove CNglcs under ensiling conditions is still unknown.

Methods

In this study, we first investigated the HCN contents in ratooning sorghums for two years, then the sorghums were ensiled with or without the addition of A. niger.

Results

Two years' investigation indicated that the contents of HCN in fresh ratooning sorghum were larger than 801 mg/kg FW (fresh weight), which could not be reduced by silage fermentation under safety threshold (200 mg/kg FW). A. niger could produce β-glucosidase over a range of pH and temperature, which degraded the CNglcs and removed the hydrogen cyanide (HCN) at early days of ratooning sorghum fermentation. The addition of A. niger (2.56 × 10⁷ CFU/ml) altered the microbial community, increased bacterial diversity, improved the nutritive qualities, and reduced the HCN contents in ensiled ratooning sorghum lower than 100 mg/kg FW after 60 days of fermentation. Overall, the addition of 150 ml A. niger + 50 ml sterile water per 3 kg silage could efficiently remove CNglcs from ratooning sorghum silage.

Conclusion

In conclusion, A. niger could produce β-glucosidase which degraded the CNglcs during the early days of fermentation, benefiting the ensiling process and improving the utilization of ratooning sorghum.

Metabolomic profiling and its association with the bio-efficacy of Aspergillus niger strain against Fusarium wilt of guava

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. The fungus Aspergillus niger is known to produce diverse metabolites with antifungal activity, attracting researchers to exploit it as a bio-control agent for plant disease control. In the present study, 11 A. niger strains were isolated and screened for their antagonism against the guava wilt pathogen under in vitro and in planta conditions. Strains were identified morphologically and molecularly by sequencing the internal transcribed spacer (ITS), β-tubulin, and calmodulin genes. The strains were evaluated through dual culture, volatile, and non-volatile methods under an in vitro study. AN-11, AN-6, and AN-2 inhibited the test pathogen Fusarium oxysporum f. sp. psidii (FOP) at 67.16%, 64.01%, and 60.48%, respectively. An in planta study was conducted under greenhouse conditions with 6 months old air-layered guava plants (var. Allahabad Safeda) by pre- and post-inoculation of FOP. The AN-11 strain was found to be effective under both pre- and post-inoculation trials. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis was carried out to characterize the volatile compounds of the most potential strain, A. niger. The hexane soluble fraction showed the appearance of characteristic peaks of hexadecenoic acid methyl ester (4.41%), 10-octadecanoic acid methyl ester (3.79%), dodecane (3.21%), undecane (3.19%), gibepyrone A (0.15%), 3-methylundecane (0.36%), and citroflex A (0.38%). The ethyl acetate fraction of the bio-control fungi revealed the occurrence of major antifungal compounds, such as acetic acid ethyl ester (17.32%), benzopyron-4-ol (12.17%), 1,2,6-hexanetriol (7.16%), 2-propenoic acid ethanediyl ester (2.95%), 1-(3-ethyloxiranyl)-ethenone (0.98%), 6-acetyl-8-methoxy dimethyl chromene (0.96%), 4-hexyl-2,5-dihydro dioxo furan acetic acid (0.19%), and octadecanoic acid (1.11%). Furthermore, bio-control abilities could be due to hyper-parasitism, the production of secondary metabolites, and competition for sites and nutrients. Indeed, the results will enrich the existing knowledge of metabolomic information and support perspectives on the bio-control mechanism of A. niger.

The hidden power of secondary metabolites in plant-fungi interactions and sustainable phytoremediation

The global environment is dominated by various small exotic substances, known as secondary metabolites, produced by plants and microorganisms. Plants and fungi are particularly plentiful sources of these molecules, whose physiological functions, in many cases, remain a mystery. Fungal secondary metabolites (SM) are a diverse group of substances that exhibit a wide range of chemical properties and generally fall into one of four main family groups: Terpenoids, polyketides, non-ribosomal peptides, or a combination of the latter two. They are incredibly varied in their functions and are often related to the increased fitness of the respective fungus in its environment, often competing with other microbes or interacting with plant species. Several of these metabolites have essential roles in the biological control of plant diseases by various beneficial microorganisms used for crop protection and biofertilization worldwide. Besides direct toxic effects against phytopathogens, natural metabolites can promote root and shoot development and/or disease resistance by activating host systemic defenses. The ability of these microorganisms to synthesize and store biologically active metabolites that are a potent source of novel natural compounds beneficial for agriculture is becoming a top priority for SM fungi research. In this review, we will discuss fungal-plant secondary metabolites with antifungal properties and the role of signaling molecules in induced and acquired systemic resistance activities. Additionally, fungal secondary metabolites mimic plant promotion molecules such as auxins, gibberellins, and abscisic acid, which modulate plant growth under biotic stress. Moreover, we will present a new trend regarding phytoremediation applications using fungal secondary metabolites to achieve sustainable food production and microbial diversity in an eco-friendly environment.

The Secondary Metabolites and Biosynthetic Diversity From Aspergillus ochraceus

Aspergillus ochraceus, generally known as a food spoilage fungus, is the representative species in Aspergillus section Circumdati. A. ochraceus strains are widely distributed in nature, and usually isolated from cereal, coffee, fruit, and beverage. Increasing cases suggest A. ochraceus acts as human and animal pathogens due to producing the mycotoxins. However, in terms of benefits to mankind, A. ochraceus is the potential source of industrial enzymes, and has excellent capability to produce diverse structural products, including polyketides, nonribosomal peptides, diketopiperazine alkaloids, benzodiazepine alkaloids, pyrazines, bis-indolyl benzenoids, nitrobenzoyl sesquiterpenoids, and steroids. This review outlines recent discovery, chemical structure, biosynthetic pathway, and bio-activity of the natural compounds from A. ochraceus.

Metabolites with antioxidant and α-glucosidase inhibitory activities produced by the endophytic fungi Aspergillus niger from Pachysandra terminalis

One new compound and 13 known compounds were isolated from Aspergillus niger, a plant endophytic fungus of Pachysandra terminalis collected from Qinling Mountains, Xi'an, China. The structure of new compound 1 was classically determined by extensive spectroscopic analysis. Compounds 5, 6, 8, and 14 were firstly reported from Aspergillus, while compound 2 was isolated from A. niger for the first time. All isolated compounds were further evaluated for their antioxidant and α-glucosidase inhibitory activities. Compounds 2 and 3 exhibited significant antioxidant activities with IC50 values of 31.64 μm and 24.32 μm, respectively, similar to the positive control ascorbic acid. Additionally, compound 1 displayed remarkable inhibitory activity against α-glucosidase with an IC50 value of 96.25 μm, which was 3.4-fold more potent than that of the positive control acarbose. Compound 1 has great potential for development as a new lead compound owing to its simple structure and remarkable biological activity.

A Special Phenotype of Aconidial Aspergillus niger SH2 and Its Mechanism of Formation via CRISPRi

The complex morphological structure of Aspergillus niger influences its production of proteins, metabolites, etc., making the genetic manipulation and clonal purification of this species increasingly difficult, especially in aconidial Aspergillus niger. In this study, we found that N-acetyl-D-glucosamine (GlcNAc) could induce the formation of spore-like propagules in the aconidial Aspergillus niger SH2 strain. The spore-like propagules possessed life activities such as drug resistance, genetic transformation, and germination. Transcriptomic analysis indicated that the spore-like propagules were resting conidia entering dormancy and becoming more tolerant to environmental stresses. The Dac1 gene and the metabolic pathway of GlcNAc converted to glycolysis are related to the formation of the spore-like propagules, as evidenced by the CRISPRi system, qPCR, and semi-quantitative RT-PCR. Moreover, a method based on the CRISPR-Cas9 tool to rapidly recycle screening tags and recover genes was suitable for Aspergillus niger SH2. To sum up, this suggests that the spore-like propagules are resting conidia and the mechanism of their formation is the metabolic pathway of GlcNAc converted to glycolysis, particularly the Dac1 gene. This study can improve our understanding of the critical factors involved in mechanisms of phenotypic change and provides a good model for researching phenotypic change in filamentous fungi.

Nutrition Component Adjustment of Distilled Dried Grain with Solubles via Aspergillus niger and Its Change about Dynamic Physiological Metabolism

The low fiber digestibility and unbalanced amino acids restricted the use of DDGS in swine diets. Key nutrition components dynamic monitoring and key regulatory pathways analysis were performed to find the rules of nutrition changes for DDGS fermented by Aspergillus niger. Cellulose and hemicellulose were reduced to 15.3% and 15.2%. 1,4-D-Xylobiose was decreased from 16.8 μg/mL to 0.2 μg/mL. Lys, Arg, and Thr were increased to 3.00%, 2.89%, and 4.40%, and met the requirements of pigs. The whole fermentation process was divided into three stages. Cellulose degradation and Lys and Arg synthesis occurred in the early stage, while Asp synthesis occurred in the last stage. α-Ketoglutarate was the key factor for Aspergillus niger degrading cellulose to synthesize Lys and Arg. The key active metabolic pathways that respond to the changes in nutrition were identified which preliminarily revealed the rules of nutrition adjustment of DDGS during fermentation with Aspergillus niger.

Aurasperone A Inhibits SARS CoV-2 In Vitro: An Integrated In Vitro and In Silico Study

Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC50 = 12.25 µM) with comparable activity with the positive control remdesivir (IC50 = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC50 = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC50 = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested Mpro to be its primary viral protein target. More potent anti-SARS CoV-2 Mpro inhibitors can be developed according to our findings presented in the present investigation.

Biocontrol Activity of Aspergillus terreus ANU-301 against Two Distinct Plant Diseases, Tomato Fusarium Wilt and Potato Soft Rot

To screen antagonistic fungi against plant pathogens, dual culture assay (DCA) and culture filtrate assay (CFA) were performed with unknown soil-born fungi. Among the different fungi isolated and screened from the soil, fungal isolate ANU-301 successfully inhibited growth of different plant pathogenic fungi, Colletotrichum acutatum, Alternaria alternata, and Fusarium oxysporum, in DCA and CFA. Morphological characteristics and rDNA internal transcribed spacer sequence analysis identified ANU-301 as Aspergillus terreus. Inoculation of tomato plants with Fusarium oxysporum f. sp. lycopersici (FOL) induced severe wilting symptom; however, co-inoculation with ANU-301 significantly enhanced resistance of tomato plants against FOL. In addition, culture filtrate (CF) of ANU-301 not only showed bacterial growth inhibition activity against Dickeya chrysanthemi (Dc), but also demonstrated protective effect in potato tuber against soft rot disease. Gas chromatography-tandem mass spectrometry analysis of CF of ANU-301 identified 2,4-bis(1-methyl-1-phenylethyl)-phenol (MPP) as the most abundant compound. MPP inhibited growth of Dc, but not of FOL, in a dose-dependent manner, and protected potato tuber from the soft rot disease induced by Dc. In conclusion, Aspergillus terreus ANU-301 could be used and further tested as a potential biological control agent.

Assignment of Absolute Configurations of Two Promising Anti-Helicobacter pylori Agents from the Marine Sponge-Derived Fungus Aspergillus niger L14

A chemical investigation into endozoic fungus Aspergillus niger L14 derived from the marine sponge of Reniera japonica collected off Xinghai Bay (China) resulted in the isolation of two dimeric naphtho-γ-pyrones, fonsecinone A (1) and isoaurasperone A (2). Through a combination of ECD spectra and X-ray diffraction analysis, the chiral axes of compounds 1 and 2 were unambiguously determined as R_α-configurations. Bioassay results indicated that these substances exhibited remarkably inhibitory effects on human pathogens Helicobacter pylori G27 and 159 with MIC values of ≤4 μg/mL, which are similar to those of the positive control, ampicillin sodium. To the best of our knowledge, this is the first report on absolute configuration of 1 and crystallographic data of 2, as well as their potent anti-H. pylori activities.