Bimetallic nanoparticles and biochar produced by Adansonia Digitata shell and their effect against tomato pathogenic fungi.

Adansonia digitata L. is a royal tree that is highly valued in Africa for its medicinal and nutritional properties. The objective of this study was to use its fruit shell extract to develop new, powerful mono and bimetallic nanoparticles (NPs) and biochar (BC) using an eco-friendly approach. Silver (Ag), iron oxide (FeO), the bimetallic Ag-FeO NPs, as well as (BC) were fabricated by A. digitata fruit shell extract through a reduction process and biomass pyrolysis, respectively, and their activity against tomato pathogenic fungi Alternaria sp., Sclerotinia sclerotiorum, Fusarium equiseti, and Fusarium venenatum were detected by agar dilution method. The Ag, FeO, Ag-FeONPs, and BC were characterized using a range of powerful analytical techniques such as ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform-Infra Red (FT-IR), dynamic light scatter (DLS), and zeta potential analysis. The fabricated Ag, FeO and Ag-FeO NPs have demonstrated a remarkable level of effectiveness in combating fungal strains. UV-Vis spectra ofAg, FeO, Ag-FeONPs, and BC show broad exhibits peaks at 338, 352, 418, and 480 nm, respectively. The monometallic, bimetallic NPs, and biochar have indicated the presence in various forms mostly in Spherical-shaped. Their size varied from 102.3 to 183.5 nm and the corresponding FTIR spectra suggested that the specific organic functional groups from the plant extract played a significant role in the bio-reduction process. Ag and Ag-FeO NPs exhibited excellent antifungal activity against pathogenic fungi Alternaria sp., S. sclerotiorum, F. equiseti, and F. venenatum. The current study could be a significant achievement in the field of antifungal agents since has the potential to develop new approaches for treating fungal infections.

Growth of alfalfa in the presence of metabolites from a dark septate endophyte strain Alternaria sp. 17463 cultured with a nonionic surfactant and emulsifier.

AIM: Dark septate endophytes (DSE) were widely used in the agriculture and ecological restoration. The objective of this work was to assess the effect of culture media nonionic surfactant and emulsifier on the biomass and metabolites of DSE strain Alternaria sp. 17463. METHODS AND RESULTS: Changes in the composition of DSE metabolites following the addition of Tween 80 during liquid culture of a DSE fungus were analyzed and used in growth tests of alfalfa.Shaking flask fermentation was carried out and the surfactant was fed to the fungus during the fermentation. The residual sugar content and pH declined significantly in the medium and the biomass of DSE increased by 7.27% over controls with no surfactant. Metabolomic analysis showed that adding the surfactant significantly increased the content of 63 metabolites (P < 0.05). These include lipids and lipid-like molecules, organooxygen compounds, amino acids and organic acids, and flavonoids. Enrichment analysis of metabolic pathways indicates that surfactant addition promoted carbohydrate metabolism and amino acid synthesis. A plant hydroponic experiment indicated that these changes in metabolites altered the root structure of alfalfa seedlings. They also promoted significant increases in root length and root surface area, and increased alfalfa total biomass by 50.2%. CONCLUSIONS: The addition of the surfactant promoted sugar utilization by the DSE fungus and increased the synthesis of lipids and amino acids, resulting in the ability of the fungal metabolites to change root structure and promote plant growth.

Three new lanostane triterpenoids and two new amides from Alternaria sp. with NLRP3 inflammasome inhibitory activity.

Three new lanostane triterpenoids (1-3) along with two new amides fatty compounds (4-5) were isolated from the ethyl acetate extract of a culture of the endophytic fungus Alternaria sp. gx-2. Their structures were identified by 1D and 2D NMR spectral data and HRESIMS. Compounds 1-12 were evaluated for their anti-inflammatory and tyrosinase inhibition activities. The isolated compounds did not show inhibitory activities at a concentration of 100 µM against tyrosinase, while under the concentration of 10 µM, the release of lactate dehydrogenase (LDH) inhibition rate of compound 1 was 54.45%, indicating that compound 1 had moderate anti-inflammatory activity on the activation of NLRP3 inflammasome.

Polyketides with IDH1 R132h and PTP1B inhibitory activities from the desert-plant-derived fungus Alternaria sp. HM 134.

Five new polyketides named alternafurones A (1) and B (2), alternapyrones M-O (3-5), together with fourteen known ones (6-19), were isolated from the desert-plant-derived fungus Alternaria sp. HM 134. The structures of the new compounds were elucidated from spectroscopic data and ECD spectroscopic analyses. Alternafurones A and B represent polyketides with an unprecedented 6/5/6 skeleton core. Compounds 1, 2 and 4 showed definite inhibitory activities against isocitrate dehydrogenase 1 gene (IDH1 R132h) with IC50 values of 29.38, 19.41 and 14.14 µg/ml, respectively. Seven compounds (6, 7, 9-12, 14) showed potent protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC50 values ranging from 0.97 µg/ml to 89.80 µg/ml.

Growth and metabolism of dark septate endophytes and their stimulatory effects on plant growth.

Dark septate endophytes (DSE) colonize plant roots extensively and increase host plant growth and nutrition. However, the development of DSE-produced metabolites as plant biostimulants has been largely ignored. DSE growth curves and extracellular metabolite components were analyzed and the growth-promoting effects of DSE extracellular metabolites on alfalfa (Medicago sativa L.) grown for 4, 8 12, 16 and 20 days were evaluated. The growth curve of the DSE strain Alternaria sp. shows days 0-8 in the growth phase, days 8-16 in the stable phase, and days 16-20 in the senescent phase. The extracellular metabolite components of DSE were significantly different at different growth stages. The biomass of alfalfa was increased significantly by DSE extracellular metabolites (P < 0.05). Biomass of alfalfa inoculated with DSE extracellular metabolites more than doubled after growth for 8 days and nutrient availability also increased significantly compared with the uninoculated control. Six DSE extracellular metabolites, calycosin 7-galactoside, 1-[(5-amino-5-carboxypentyl)amino]-1-deoxyfructose, N2-fructopyranosylarginine, 2-(4-methyl-5-thiazolyl)ethyl hexanoate, kenposide B, and medinoside E, were significantly positively correlated with alfalfa biomass (P < 0.01). This study combines the DSE extracellular metabolites with plant and soil traits to provide a theoretical basis for the use of DSE metabolites in the product development of plant biostimulants.

Polyketides with anti-inflammatory activity from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7.

Seven undescribed polyketides with particular ortho-trisubstituted benzo[c]furan and benzo[c]oxepin spiro structures were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7. Structural elucidations of these compounds were determined mainly by NMR and HR-ESI-MS analysis. An assumed polyketide biosynthetic pathway of these isolates was proposed. Two undescribed compounds and four known compounds showed significant inhibitory effects on LPS-induced NO production in RAW 264.7 cells without cytotoxicity at their effective concentrations.

Two New Sulfate-Modified Dibenzopyrones With Anti-foodborne Bacteria Activity From Sponge-Derived Fungus Alternaria sp. SCSIOS02F49.

At present, foodborne diseases (FBDs) caused by bacteria are gradually increasing every year, and the development of new antibiotics is an urgent necessity for human beings. To find novel antibacterial compounds, three sponge-derived fungal strains (SCSIOS02F40, F46, and F49) were investigated. As a result, Alternaria sp. SCSIOS02F49 was selected for investigation on its secondary metabolites because its ethyl acetate (EtOAc) extract of potato dextrose broth (PDB) culture showed rich metabolites and strong antibacterial activity. Two new dibenzopyrones with rare sulfate group (1-2), together with 10 known compounds (3-12), were isolated from the Alternaria sp. SCSIOS02F49. Their structures were confirmed by nuclear magnetic resonance (NMR), mass spectrometry (MS) data, and comparison with data from the relevant literature. Almost all compounds showed moderate inhibitory activity against eight foodborne bacteria (FBB) with minimum inhibitory concentration (MIC) values in the range of 15.6-250 µg/ml, and minimum bactericidal concentration (MBC) values in the range of 31.3-250 µg/ml. The antibacterial mechanism of compound 1 was preliminarily investigated using growth curves, scanning electron microscopy (SEM), and flow cytometry (FCM), which revealed that compound 1 altered the external structure of Staphylococcus aureus and caused the rupture or deformation of the cell membranes. This research provides lead compounds for the development of new antibiotics or microbial preservatives.

Diverse polyketides from the marine endophytic Alternaria sp. LV52: Structure determination and cytotoxic activities.

We report the isolation and characterization of five polyketides [alternariol (1), alternariol-9-methyl ether (2), altertoxin I (3), altertoxin II (4) and tenuazonic acid (5)] from the marine endophytic Alternaria sp. LV52 derived from Cystoseira tamariscifolia, collected from the Red Sea at Nabq-Bay, Egypt. The chemical structures of compounds 1-5 were identified by extensive 1D, 2D NMR, and HR mass measurements. Isolation and phenotypic and genotypic characterization of the producing fungus is reported. The antimicrobial activity of the produced extract and derived compounds was examined against a panel of test organisms. In addition, an in vitro cytotoxic activity of 1-5 was performed against diverse cancer cell lines: HEPG2, HELA, A549 and PC3, revealing that compounds 2 and 4 are potentially cytotoxic against A549 and PC3 with EC50 of 0.73 µg/ml (2.69 µM) and 0.17 µg/ml (0.64 µM) for 2, and 0.40 µg/ml (1.15 µM) and 0.12 µg/ml (0.33 µM) for 4, respectively.

Three new phomalone derivatives from a deep-sea-derived fungus Alternaria sp. MCCC 3A00467.

Three new phomalone derivatives, phomalichenones E-G (1-3), and seven known analogues (4-10) were isolated from the cultures of a deep-sea-derived fungus Alternaria sp. MCCC 3A00467. Their structures were elucidated by spectroscopic methods, including the 1D and 2D NMR, and ECD spectrum. Among the compounds isolated, phomalichenone F (2) presented cytotoxic activity against human myeloma cancer U266 cells with IC50 value of 24.99 µg/mL. The most active compound, 10, showed cytotoxicity against U266, HepG2 and A549 cells with IC50 values of 13.26, 14.69 and 24.39 µg/mL, respectively.

Research on the antioxidant activity of metabolites from a sponge-derived fungus Alternaria sp. F49 / 药学学报

To study the chemical constituents from the the deep-sea fungus Alternaria sp. F49. Seven compounds were isolated from the EtOAc extract by using silica gel, Sephadex LH-20, ODS and HPLC methods. Based on the spectroscopic analysis, their structures were identified as (8R)-5-O-methyl-orcinotriol (1), orcinotriol (2), α-acetylorcinol (3), 3'-hydroxyalternariol 5-O-methyl ether (4), altenusiol (5), altenusin (6), and 5'-methoxy-6-methyl-biphenyl-3,4,3'-triol (7). (8R)-5-O-Methyl-orcinotriol (1) is a new phenolic compound which has never been reported in the literature. Compounds 4-7 showed strong DPPH free radical scavenging activity; whereas compounds 1-7 showed strong ABTS free radical scavenging activity.

Optimization of microwave assisted extraction of Artocarpus Heterophyllus leaf polyphenols with inhibitory action against Alternaria sp. and antioxidant capacity.

The Artocarpus heterophyllus extracts are receiving attention due to their agro-food applications. Then, the simultaneous optimization of microwave-assisted extraction of polyphenols from jackfruit leaf with growth inhibitory action against Alternaria sp. was studied. The effects of power and time on total soluble polyphenols and total flavonoids contents, and antifungal activity were investigated using response surface methodology. Temperature behavior was considered also. Models showed good prediction and successfully validation. Treatment at 840 W and 2 min allowed the responses maximization (148.75 mg galic acid equivalent /g dried weight of total soluble polyphenols, 13.28 mg rutin equivalent /g dried weight of total flavonoids, and 39.9% of antifungal activity). Furthermore, high ABTS+ (97%) and DPPH (92%) inhibition was exhibited, as a function of the polyphenol's concentration and composition. Mainly flavonoids with potential antioxidant and antifungal properties were detected. These findings suggest the potentialities of these extracts for Alternaria sp. control during tomato postharvest.

Polyketone metabolites isolated from Rhodiola tibetica endohytic fungus Alternaria sp. HJT-Y7 and their SARS-CoV-2 virus inhibitory activitives.

Six new polyketone metabolites, compounds (1-6) and seven known polyketone compounds (7-13) were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. The structural elucidation of five new polyketone metabolites were elucidated on the basis of spectroscopic including 2D NMR and HRMS and spectrometric analysis. Inhibition rate evaluation revealed that compounds 1(EC50 = 0.02 mM), 3(EC50 = 0.3 mM), 6(EC50 = 0.07 mM), 8(EC50 = 0.1 mM) and 9(EC50 = 0.04 mM) had inhibitory effect on the SARS-CoV-2 virus.

Recent Progress in Enhancing Fungal Disease Resistance in Ornamental Plants.

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.

Diverse anti-inflammation and anti-cancer polyketides isolated from the endophytic fungi Alternaria sp. MG1.

Six new polyketides, alternaritins A-D [(±)-1-4] and isoxanalteric acid I (8), and 25 known Alternaria toxins were isolated from the culture of an endophytic fungi Alternaria sp. MG1. 3 is a rare fungal metabolite. 6 is a new natural product, and 5, 7, and 9 are known previously but their absolute configurations have not been determined. Three enantiomers [(±)-1, (±)-7, and (±)-15] were separated via chiral HPLC resolution. The structures of those polyketides (1-9) were elucidated by spectrometric analysis using MS and NMR. The absolute configurations were established using X-ray diffraction analysis and statistical comparative analysis of the experimental ECD and OR data, in conjunction with quantum mechanical calculations. All of the compounds were evaluated for their bioactivities. Known compound 27 exerted the most potent cytotoxic activities against HT-1080 and NCI-H1299 cell lines. The new compounds, 2 and 3, showed moderate inhibition on COX-2, while a pair of isomers, 8 and 9, exhibited medium activity on COX-2 and uropathogenic Escherichia coli.

Two new cephalochromin derivative from the Alternaria sp. ZG22.

Two new cephalochromin derivatives, prenylcephalochromin A (1), prenylcephalochromin B (2), along with cephalochromin (3) were isolated from the Alternaria sp. ZG22 obtained from a Dasymaschalon rostratum collected from the Hainan. The structures of two new compounds were elucidated by comprehensive spectroscopic methods. Compounds 1-3 showed α-glucosidase inhibitory activity.

Secondary metabolites of endophyte Alternaria sp. W-1 from Laminaria japonica / 药学学报

Six compounds were isolated from the crude extract of the liquid culture of Alternaria sp. W-1 by silica gel column chromatography, Sephadex LH-20 gel column chromatography, and HPLC. They were identified as 6-iso-tricycloalternarene 6a (1), tricycloalternarene 6a (2), tricycloalternarene B (3), uracil (4), 5-methyluracil (5), and lumichrome (6) through HR-MS, NMR and literature comparison. 6-iso-Tricycloalternarene 6a (1) is a new compound which has never been reported in the literature. In cytotoxicity assay, compounds 1-3 showed weak inhibition activity to human hepatoma cell line SMMC-7721 and human gastric cell line SGC-7901.

Cytotoxic Meroterpenoids from the Fungus Alternaria sp. JJY-32.

Two new meroterpenoids, tricycloalternarenes X and Y, together with one known meroterpenoid, tricycloalternarene I, were isolated from the fungus Alternaria sp. JJY-32. The structures including absolute configurations were established by the comprehensive spectroscopic data, electronic circular dichroism (ECD) spectral analyses, and biosynthesis consideration. Tricycloalternarene X showed cytotoxicity against the HL-60 and HO8910 cells with IC50 values of 7.54 and 20.32 µm.

Metabolomics Reveals the Response of the Phenylpropanoid Biosynthesis Pathway to Starvation Treatment in the Grape Endophyte Alternaria sp. MG1.

Phenylpropanoid (PPPN) compounds are widely used in agriculture, medical, food, and cosmetic industries because of their multiple bioactivities. Alternaria sp. MG1, an endophytic fungus isolated from grape, is a new natural source of PPPNs. However, the PPPN biosynthesis pathway in MG1 tends to be suppressed under normal growth conditions. Starvation has been reported to stimulate the PPPN pathway in plants, but this phenomenon has not been well studied in endophytic fungi. Here, metabolomics analysis was used to examine the profile of PPPN compounds, and quantitative reverse transcription-polymerase chain reaction was used to detect the expression of key genes in the PPPN biosynthesis pathway under starvation conditions. Starvation treatment significantly increased the accumulation of shikimate and PPPN compounds and upregulated the expression of key genes in their biosynthesis pathways. In addition to previously reported PPPNs, sinapate, 4-hydroxystyrene, piceatannol, and taxifolin were also detected under starvation treatment. These findings suggest that starvation treatment provides an effective way to optimize the production of PPPN compounds and may permit the investigation of compounds that are undetectable under normal conditions. Moreover, the diversity of its PPPNs makes strain MG1 a rich repository of valuable compounds and an extensive genetic resource for future studies.

Molecular heterogeneity in the 18s DNA gene of Alternaria sp. and Fusarium sp. producing mycotoxins in rice and maize grains.

BACKGROUND: Food contaminated with fungi and their toxins is a problem that threatens many developing countries. Kingdom of Saudi Arabia depends on the exported grain and legume seeds. MATERIALS AND METHODS: The study involved examination of 160 samples of rice and maize seeds collected from different locations in the Kingdom of Saudi Arabia. Heterogeneity in the 18s rRNA gene of toxigenic Alternaria sp. and Fusarium sp. was unraveled. The seeds were disinfected and cultured on Potato Dextrose Agar (PDA), Yeast Extract Sucrose (YES) media and incubated at 25 °C/7 days. The isolated fungi were subjected to 18s rRNA gene sequencing. Five toxins were extracted from maize and rice grains infected with isolated fungi. RESULTS: The isolated fungi were identified based on morphological and spores characters as Fusarium sp. and Alternaria sp. Molecular identification based on18s rDNA barcode' was performed due to its high degree of inter specific variability, conserved primer sites and multi-copy nature in the genome. Fusarium sp. produced the highest detected (2070 µg/kg) fumonisin especially in cereal production season 2011. The collected grain from Dammam recorded the highest percentage (5485.2 g/kg) of toxins. CONCLUSION: This work highlights that 50% of samples were found contaminated with toxins in various concentrations which impose a threat for public health and necessitate rapid identification methods for toxigenic fungi such as 18s rDNA sequencing.

Enzymatic rhamnosylation of anticancer drugs by an α-L-rhamnosidase from Alternaria sp. L1 for cancer-targeting and enzyme-activated prodrug therapy.

The synthesis of rhamnosylated compounds has gained great importance since these compounds have potential therapeutic applications. The enzymatic approaches for glycosylation of bioactive molecules have been well developed; however, the enzymatic rhamnosylation has been largely hindered by lacking of the glycosyl donor for rhamnosyltransferases. Here, we employed an α-L-rhamnosidase from Alternaria sp. L1 (RhaL1) to perform one-step rhamnosylation of anticancer drugs, including 2'-deoxy-5-fluorouridine (FUDR), cytosine arabinoside (Ara C), and hydroxyurea (Hydrea). The key synthesis conditions including substrate concentrations and reaction time were carefully optimized, and the maximum yields of each rhamnosylated drugs were 57.7 mmol for rhamnosylated Ara C, 68.6 mmol for rhamnosylated Hydrea, and 42.2 mmol for rhamnosylated FUDR. It is worth pointing out that these rhamnosylated drugs exhibit little cytotoxic effects on cancer cells, but could efficiently restore cytotoxic activity when incubated with exogenous α-L-rhamnosidase, suggesting their potential applications in the enzyme-activated prodrug system. To evaluate the cancer-targeting ability of rhamnose moiety, the rhamnose-conjugated fluorescence dye rhodamine B (Rha-RhB) was constructed. The fluorescence probe Rha-RhB displayed much higher cell affinity and cellular internalization rate of oral cancer cell KB and breast cancer cell MDA-MB-231 than that of the normal epithelial cells MCF 10A, suggesting that the rhamnose moiety could mediate the specific internalization of rhamnosylated compounds into cancer cells, which greatly facilitated their applications for cancer-targeting drug delivery.