scholarly journals Biofilm Mode of Cultivation Leads to an Improvement of the Entomotoxic Patterns of Two Aspergillus Species

2020 ◽  
Vol 8 (5) ◽  
pp. 705
Author(s):  
Frédéric Francis ◽  
Florent Druart ◽  
José Diana Di Mavungu ◽  
Marthe De Boevre ◽  
Sarah De Saeger ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Aspergillus Flavus ◽  
Aspergillus Oryzae ◽  
Proteomic Analysis ◽  
Cyclopiazonic Acid ◽  
Aspergillus Species ◽  
Metabolite Profiles

Two fungi, i.e., Aspergillus flavus Link and Aspergillus oryzae (Ahlb.) E. Cohn, were cultivated according to two methodologies, namely submerged and biofilm cultures with the primary aim to use their secondary metabolites the supernatant CL50, and CL90 varied between 1.3% (v/v) to 12.7% (v/v) for incubation times from 24 to 72 h. While the A. flavus supernatant entomotoxicity was higher than this of A. oryzae, the biofilm culture application increased the efficiency of the former. Proteomic analysis of the supernatants revealed discrepancies among the two species and modes of cultivation. Furthermore, the secondary metabolite profiles of both Aspergillus cultures were verified. Aspergillic acid, beta-cyclopiazonic acid, cyclopiazonic acid, ferrineospergillin, flavacol, and spermadin A were most predominant. Generally, these secondary metabolites were present in higher concentrations in the supernatants of A. flavus and biofilm cultures. These molecular identifications correlated positively with entomotoxic activity. Noteworthy, the absence of carcinogenic aflatoxins was remarkable, and it will allow further valorization to produce A. flavus to develop potential biopesticides.

scholarly journals Vibrio gazogenes inhibits aflatoxin production through downregulation of aflatoxin biosynthetic genes in Aspergillus flavus

2022 ◽  
Author(s):  
Shyam L. Kandel ◽  
Rubaiya Jesmin ◽  
Brian M. Mack ◽  
Rajtilak Majumdar ◽  
Matthew K. Gilbert ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Aspergillus Flavus ◽  
Fungal Biomass ◽  
Expression Profiles ◽  
Health Hazard ◽  
Gene Clusters ◽  
Aflatoxin Contamination ◽  
Aflatoxin Biosynthesis ◽  
Control Samples

Aspergillus flavus is an opportunistic pathogen of oilseed crops such as maize, peanut, cottonseed, and tree nuts and produces carcinogenic secondary metabolites known as aflatoxins during seed colonization. Aflatoxin contamination not only reduces the value of the produce but also is a health hazard to humans and animals. Previously, we observed inhibition of A. flavus aflatoxin biosynthesis upon exposure to the marine bacterium, Vibrio gazogenes (Vg). In this study, we used RNA sequencing to examine the transcriptional profiles of A. flavus treated with both live and heat-inactivated dead Vg and control samples. Fungal biomass, total accumulated aflatoxins, and expression profiles of genes constituting secondary metabolite biosynthetic gene clusters were determined at 24, 30, and 40 h after treatment. Statistically significant reductions in total aflatoxins were detected in Vg-treated samples as compared to control samples at 40 h. But no statistical difference in fungal biomass was observed upon these treatments. The Vg treatments were most effective on aflatoxin biosynthesis as was reflected in significant downregulation of majority of the genes in the aflatoxin gene cluster including the aflatoxin pathway regulator gene, aflR. Along with aflatoxin genes, we also observed significant downregulation in some other secondary metabolite gene clusters including cyclopiazonic acid and aflavarin, suggesting that the treatment may inhibit other secondary metabolites as well. Finally, a weighted gene correlation network analysis identified an upregulation of ten genes that were most strongly associated with Vg-dependent aflatoxin inhibition and provide a novel start-point in understanding the mechanisms that result in this phenomenon.

scholarly journals Different Secondary Metabolite Profiles of Phylogenetically almost Identical Streptomyces griseus Strains Originating from Geographically Remote Locations

2019 ◽  
Vol 7 (6) ◽  
pp. 166 ◽  
Author(s):  
Ignacio Sottorff ◽  
Jutta Wiese ◽  
Matthias Lipfert ◽  
Nils Preußke ◽  
Frank D. Sönnichsen ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Secondary Metabolite ◽  
Streptomyces Griseus ◽  
Garden Soil ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Metabolite Profiles

As Streptomyces have shown an outstanding capacity for drug production, different campaigns in geographically distant locations currently aim to isolate new antibiotic producers. However, many of these newly isolated Streptomyces strains are classified as identical to already described species. Nevertheless, as discrepancies in terms of secondary metabolites and morphology are possible, we compared two Streptomyces strains with identical 16S rRNA gene sequences but geographically distant origins. Chosen were an Easter Island Streptomyces isolate (Streptomyces sp. SN25_8.1) and the next related type strain, which is Streptomyces griseus subsp. griseus DSM 40236T isolated from Russian garden soil. Compared traits included phylogenetic relatedness based on 16S rRNA gene sequences, macro and microscopic morphology, antibiotic activity and secondary metabolite profiles. Both Streptomyces strains shared several common features, such as morphology and core secondary metabolite production. They revealed differences in pigmentation and in the production of accessory secondary metabolites which appear to be strain-specific. In conclusion, despite identical 16S rRNA classification Streptomyces strains can present different secondary metabolite profiles and may well be valuable for consideration in processes for drug discovery.

scholarly journals Cleaning the Cellular Factory–Deletion of McrA in Aspergillus oryzae NSAR1 and the Generation of a Novel Kojic Acid Deficient Strain for Cleaner Heterologous Production of Secondary Metabolites

2021 ◽  
Vol 2 ◽  
Author(s):  
Trong T. Dao ◽  
Kate M. J. de Mattos-Shipley ◽  
Ian M. Prosser ◽  
Katherine Williams ◽  
Marija K. Zacharova ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Natural Product ◽  
Secondary Metabolite ◽  
Aspergillus Oryzae ◽  
Kojic Acid ◽  
Negative Regulator ◽  
Secondary Metabolite Production ◽  
Phenotypic Change ◽  
Metabolite Production ◽  
Host Strains

The use of filamentous fungi as cellular factories, where natural product pathways can be refactored and expressed in a host strain, continues to aid the field of natural product discovery. Much work has been done to develop host strains which are genetically tractable, and for which there are multiple selectable markers and controllable expression systems. To fully exploit these strains, it is beneficial to understand their natural metabolic capabilities, as such knowledge can rule out host metabolites from analysis of transgenic lines and highlight any potential interplay between endogenous and exogenous pathways. Additionally, once identified, the deletion of secondary metabolite pathways from host strains can simplify the detection and purification of heterologous compounds. To this end, secondary metabolite production in Aspergillus oryzae strain NSAR1 has been investigated via the deletion of the newly discovered negative regulator of secondary metabolism, mcrA (multicluster regulator A). In all ascomycetes previously studied mcrA deletion led to an increase in secondary metabolite production. Surprisingly, the only detectable phenotypic change in NSAR1 was a doubling in the yields of kojic acid, with no novel secondary metabolites produced. This supports the previous claim that secondary metabolite production has been repressed in A. oryzae and demonstrates that such repression is not McrA-mediated. Strain NSAR1 was then modified by employing CRISPR-Cas9 technology to disrupt the production of kojic acid, generating the novel strain NSARΔK, which combines the various beneficial traits of NSAR1 with a uniquely clean secondary metabolite background.

scholarly journals Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

Toxins ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 74-99 ◽  
Author(s):  
Perng-Kuang Chang ◽  
Kenneth Ehrlich ◽  
Isao Fujii
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Oryzae ◽  
Cyclopiazonic Acid ◽  
Acid Biosynthesis

scholarly journals Occurrence of Aflatoxigenic Aspergillus Species in Various Varieties of Peanuts Produced in Western Kenya

2017 ◽  
Author(s):  
Menza C. Nelson ◽  
Muturi W. Margaret ◽  
Lucy Kamau
Keyword(s):  
Aspergillus Flavus ◽  
Dominant Species ◽  
Aspergillus Parasiticus ◽  
Cyclopiazonic Acid ◽  
Aspergillus Species ◽  
Western Kenya ◽  
Central District ◽  
Aspergillus Section

Aflatoxin contaminates foods including peanuts. Aflatoxin is a carcinogenic toxin mainly produced bty Aspergillus flavus. Other Aspergillus species that rarely produce aflatoxins are A. nomius and A. niger. Aflatoxin is associated with liver failure, hepatocellular carcinoma (HCC) and death. Recent studies have shown that peanuts in Kenya are highly contaminated with aflatoxins but information gaps exist on the characterization of the Aspergillus species that produce aflatoxins in peanuts in Kenya. Therefore, this gap necessitated the determination of the Aspergillus species producing aflatoxins in peanuts from the main growing districts of Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district Aspergillus species were isolated from the peanut samples by using the dilution plate technique on modified Rose Bengal agar. Phenotypical characterization of the identified Aspergillus section flavus isolates from the peanuts samples was determined using the procedure of Mellon and Cotty. This study identified five (5) Aspergillus species as contaminants in peanuts analyzed in this study. They were Aspergillus flavus L-strain, Aspergillus flavus S-strain, Aspergillus parasiticus, Aspergillus niger and Aspergillus tamari. Overall, the occurrence of Aspergillus flavus L- strain and A. flavus S- strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus S-strain was the most dominant species identified in the study with a mean occurrence of 45.1%. Aspergillus flavus L- strain was the most common isolate (58.8%) in peanuts from Busia district while A. flavus S- strain was the most common strain (60.2%) in peanuts from Kisii Central district. Overall, the occurrence of Aspergillus flavus L strain and A. flavus S strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus S-strain was the most dominant species (F=3.15, df =25, P=0.031) with an overall mean occurrence of 45.1%. The confirmation of occurrence of other species that produce toxins such as A. niger and A. tamarii which also produces cyclopiazonic acid suggests the need to screen peanuts for other carcinogenic mycotoxins.

scholarly journals An Updated Review on the Secondary Metabolites and Biological Activities of Aspergillus ruber and Aspergillus flavus and Exploring the Cytotoxic Potential of Their Isolated Compounds Using Virtual Screening

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Fadia S. Youssef ◽  
Abdel Nasser B. Singab
Keyword(s):  
Secondary Metabolites ◽  
Aspergillus Flavus ◽  
Topoisomerase Ii ◽  
High Resolution Mass Spectrometry ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
2D Nmr ◽  
Aspergillus Species ◽  
Cytotoxic Potential ◽  
In Silico Studies

The secondary metabolites and biological activities of Aspergillus ruber and Aspergillus flavus were comprehensively reported. About 70 compounds were isolated from both species that belong to different classes using conventional and advanced chromatographic techniques and unambiguously elucidated employing one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) and high resolution mass spectrometry (HRMS). Some of them displayed promising antiviral, anti-inflammatory, and antioxidant activities. In silico studies were conducted on human cyclin-dependent kinase 2 (CDK-2), human DNA topoisomerase II (TOP-2), and matrix metalloprotinase 13 (MMP-13) in an effort to explore the cytotoxic potential of the diverse compounds obtained from both Aspergillus species. 1,6,8-Trihydroxy-4-benzoyloxy-3-methylanthraquinone (23) revealed the most firm fitting with the active pockets of CDK-2 and MMP-13; meanwhile, variecolorin H alkaloid (14) showed the highest fitting within TOP-2 with ∆G equals to −36.51 kcal/mole. Thus, fungal metabolites could offer new drug entities for combating cancer. Relevant data about both Aspergillus species up to August 2020 were gathered from various databases comprising Scifinder (https://scifinder.cas.org/scifinder/login) for secondary metabolite-related studies; meanwhile, for biology-related articles, data were collected from both PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) and Web of Knowledge (http://www.webofknowledge.com) as well.

scholarly journals The Influence of Seasonality on Secondary Metabolite Profiles and Neuroprotective Activities of Moss Hypnum cupressiforme Extracts: In Vitro and In Silico Study

Plants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Tanja M. Lunić ◽  
Marija R. Mandić ◽  
Mariana M. Oalđe Pavlović ◽  
Aneta D. Sabovljević ◽  
Marko S. Sabovljević ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Biological Activities ◽  
Hypnum Cupressiforme ◽  
Tnf Α ◽  
In Silico Study ◽  
Metabolite Profiles ◽  
Metabolite Content

Numerous representatives of mosses, including Hypnum cupressiforme, have been used to alleviate different inflammation-related conditions. However, the mode of action underlying this anti-inflammatory potential has been poorly understood. Moreover, the influence of seasonality on the chemical composition and biological activity of mosses is generally overlooked. This study aimed to investigate the influence of seasonal changes (spring, summer, and autumn) on secondary metabolite composition and biological activities of ethyl acetate H. cupressiforme extracts. Antioxidant activity was measured using β-carotene bleaching assay, while MTT, NBT, ELISA, and Griess assays were carried out to explore the anti-neuroinflammatory and neuroprotective potential of extracts. Inhibitory activities on acetylcholinesterase and tyrosinase were assessed experimentally and by docking analysis. The highest content of secondary metabolites and antioxidant activity were observed in moss during the summer. Extracts inhibited the secretion of ROS, NO, TNF-α, and IL-6, alleviating the inflammatory potential of H2O2 and LPS in microglial and neuronal cells. Strong inhibitory effects on acetylcholinesterase and tyrosinase were observed in vitro. Docking analyses revealed high-affinity interactions of secondary metabolites present in H. cupressiforme with important enzyme residues. Altogether, these results reveal the neuroprotective potential and the significance of seasonal fluctuations on secondary metabolite content and biological activities in moss H. cupressiforme.

scholarly journals Liquid Chromatographic Determination of Major Secondary Metabolites Produced by Aspergillus Species from Section Flavi

1998 ◽  
Vol 81 (1) ◽  
pp. 57-60 ◽  
Author(s):  
Victor S Sobolev ◽  
Bruce W Horn ◽  
Joe W Dorner ◽  
Richard J Cole
Keyword(s):  
Secondary Metabolites ◽  
Cyclopiazonic Acid ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Aspergillus Species ◽  
Uv Detector ◽  
Tetrabutylammonium Hydroxide ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for simultaneous determination of major secondary metabolites—including cyclopiazonic acid (CPA), O-methylsterigmatocystin (OMST), and the versicolorins—produced by Aspergillus species from section Flavi (A. flavus, A. parasiticus, A. tamarii, and A. caelatus) on a liquid medium. Metabolites were extracted with chloroform and quantitated without prior cleanup by means of normal- phase ion-pair partition LC on silica gel with a mobile phase of n-heptane-2-propanol-n-butanolwater- tetrabutylammonium hydroxide (2560 + 900 + 230 + 32 + 8, v/v). Recoveries of CPA and OMST from fungal cultures spiked at 10 μg/mL were 98.90 + 3.27 and 95.92 + 5.27% (n = 5), respectively. At spike levels of 100 μg/mL, recoveries were 98.89 + 3.87 and 97.65 + 4.32% (n = 5), respectively. Limits of detection for pure standards were 0.25 μg/mL for CPA (at 280 nm) and 0.30 μg/mL for OMST (at 310 nm). UV detector responses to CPA and OMST were linear to about 0.5 and 3.5 μg/injection, respectively

Genome sequence of Novosphingobium malaysiense strain MUSC 273T, novel alpha-proteobacterium isolated from intertidal soil

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Hooi-Leng Ser ◽  
Wai-Fong Yin ◽  
Kok-Gan Chan ◽  
Nurul-Syakima Ab Mutalib ◽  
Learn-Han Lee
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Genome Sequence ◽  
Catalase Activity ◽  
Gene Clusters ◽  
Rrna Genes ◽  
Gram Negative ◽  
Genomic Features

Novosphingobium malaysiense strain MUSC 273T is a recently identified Gram-negative, aerobic alpha-proteobacterium. The strain was isolated from intertidal soil with strong catalase activity. The genome sequence comprises 5,027,021 bp, with 50 tRNA and 3 rRNA genes. Further analysis identified presence of secondary metabolite gene clusters within genome of MUSC 273T. Knowledge of the genomic features of the strain may allow further biotechnological exploitation, particularly for production of secondary metabolites as well as production of industrially important enzymes

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