Search Results (30)

Twelve undescribed peptidic compounds, bukhansantaibols A–K (1–10) and bukhansantaibals A–B (11–12), were isolated from the soil fungus Trichoderma atroviride through LC-MS and bioactivity-guided purification. Their structures were elucidated by the analysis of 1D and 2D NMR spectra, HRESIMS, and acid hydrolysis using modified Marfey’s method. All compounds were evaluated for their cytotoxic activity against HCT-8 (colon cancer) and SK-OV-3 (ovarian cancer) cells. Among them, compounds 1–5 exhibited significant inhibitory effects, with IC₅₀ values ranging from 2.1 to 19.6 μM. Full article

The potential of Trichoderma fungi as biocontrol agents has not yet been fully explored, as there is a large repertoire of inter- and intra-species variation in their phytopathogenic antagonistic effects due to different adaptations of individual Trichoderma strains. In the present study, we investigated the biocontrol efficacy of eight native isolates of Trichoderma spp. against the soilborne phytopathogens Sclerotinia sclerotiorum and Rhizoctonia solani and a representative of the Mucoromycota, Phycomyces blakesleeanus. An in vitro dual culture test showed a complete (100%) inhibition of S. sclerotiorum and P. blakesleeanus by each tested Trichoderma strain and a high (80–100%) inhibition of R. solani. The crude chloroform extracts, whose peptide contents were confirmed by thin-layer chromatography, caused a concentration-dependent reduction in the growth of the target fungi, with inhibition comparable to the effect of the peptaibol standard alamethicin. Despite the differences between fungi from the phyla Basidiomycota, Ascomycota, and Mucoromycota, their inhibition by alamethicin followed the same dose–response dependence. The growth inhibition of P. blakesleeanus induced by Trichoderma extracts was characterized by a significantly increased activity of antioxidative defense enzymes. Both variants of biocontrol agents, the native strains of Trichoderma spp. and their extracts, are efficient in controlling fungal growth and should be considered for the development of new potent bioformulations applicable in agriculture. Full article

Peptaibols are linear fungal peptides featuring α,α-dialkylated amino acids (e.g., α-aminoisobutyric acid (Aib), isovaline (Iva)) and characteristic C-terminal alcohol groups. Despite their promising antibacterial and antiplasmodial activities, detailed biosynthetic studies remain limited. A genome-guided study of the fungus Trichodema sp. SK1-7, isolated from decaying wood, revealed the production of previously described trichorozin IV (1), along with novel SF4-type peptaibol 2 (trichorozin V). The structures of these compounds were elucidated through MS analysis, NMR study and advanced Marfey’s method. The genome of Trichoderma sp. SK1-7 harbors two PKS-NRPS hybrid gene clusters containing 14 and 18 adenylation domains. Analysis of the modular architecture suggested that trichorozins are synthesized by a 14-module protein via a module skipping mechanism. Genome mining revealed several types of short peptaibol synthase architectures (10–14 adenylation domains) across various Trichoderma species, accompanied by similar long peptaibol synthases. Furthermore, putative Aib/Iva biosynthesis machinery in Trichoderma was identified, showing specific architectures potentially involved in regulating peptaibol biosynthesis. Feeding experiments demonstrated that peptaibol production depends on the ratio of Iva/Aib. The isolated compounds exhibited moderate antibacterial and cytotoxic activities along with a synergistic effect when combined with membrane-targeting antibiotics. Our findings suggest that genome-guided approaches hold promise for further development of peptabiotics with a wide range of applications, including antibiotic adjuvants. Full article

Lanzhou lily is a plant native to China with high edible, medicinal, and ornamental value that is relatively susceptible to Fusarium wilt. In this study, the application of Trichoderma longibrachiatum SMF2 (TlSMF2) effectively controlled Lanzhou lily wilt disease caused by Fusarium oxysporum and F. solani. TlSMF2 and the antimicrobial peptaibols trichokonins (TKs) produced by TlSMF2 inhibited the mycelial growth and spore germination of these two pathogens. Transcriptome analysis revealed that the TKs-induced defense responses of Lanzhou lily were mainly related to the production of plant hormones and defense enzymes. In detail, TKs treatment increased the levels of salicylic acid (SA) and jasmonic acid (JA) and the expression of their related genes and upregulated the activities of chitinase and phenylalanine ammonia-lyase (PAL). Moreover, TKs caused the induction of LzWRKY26 and LzWRKY75, which is highly homologous to LrWRKY3 that positively regulates Lilium regale resistance to F. oxysporum. LzWRKY26 expression was also induced by SA and MeJA treatments and F. oxysporum infection, which was consistent with the findings that many cis-acting elements associated with phytohormones and stress responses are present in the promoter region of LzWRKY26. Therefore, the biocontrol mechanisms of TlSMF2 against Lanzhou lily wilt disease involve substrate competition and toxicity against pathogens, as well as the induction of systemic resistance in plants. Our results highlight a promising biological control agent for soil-borne fungal diseases and offer deeper insights into the biocontrol mechanisms of TlSMF2. Full article

Pear fruit brown rot, caused by Monilia yunnanensis, affects pear fruit yields and quality. The present study determined Trichoderma longibrachiatum T6 (T6) peptaibols as a biological control alternative to synthetic fungicides and assessed its efficacy against M. yunnanensis through dual plate culture and surface spraying at different concentrations. T6 peptaibols effectively inhibited M. yunnanensis growth, achieving an 85.99% inhibitory rate at 1250 µg/mL after inoculation on PDA medium for 5 days, and 84.57% control efficacy on pear fruit with the same concentration at 6 days. Treatment with T6 peptaibols significantly decreased the average contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), as well as electrolyte leakage, by 31.99%, 27.93%, and 21.00% from days 1 to 9 post-inoculation, respectively, in comparison to the negative control. Additionally, the average antioxidant enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) increased by 86.27%, 56.76%, 25.94%, and 47.88%, respectively; the average defense enzyme activities of phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), chitinase (CHI), and β-1,3-glucanase (β-Glu) increased by 63.00%, 55.70%, 26.19%, and 16.34%, respectively. Moreover, the expression levels of the antioxidant and defense-related genes (CAT, SOD, POD, PPO, CHI, LOX, PAL, β-Glu) were significantly upregulated by 2.80, 2.81, 3.03, 2.79, 3.37, 2.49, 2.73, and 1.83-folds at 3 days after inoculation compared to the negative control. Thus, T6 peptaibols effectively reduced the pathogen infection through growth inhibition and antioxidant defenses, thereby boosting fruit immunity. Full article

We previously reported on a novel peptaibol, named Tripleurin XIIc (TPN), an 18-residue long sequence produced by the fungus Trichoderma pleuroti. We elucidated its 3D structure via classical and accelerated molecular dynamics simulation (aMD) methods and reported the folding dynamics of TPN in water and chloroform solvents. Peptaibols, in general, are insoluble in water, as they are amphipathic and may prefer hydrophobic environments like transmembrane regions. In this study, we attempted to use aMD simulations to model an all-atom bacterial membrane system while placing a TPN molecule in its vicinity. The results highlighted that TPN was able to introduce some disorder into the membrane and caused lipid clustering. It could also enter the transmembrane region from the water-bilayer interface. The structural dynamics of TPN in the transmembrane region revealed a single energetically stable conformation similar to the one obtained from water and chloroform solvent simulations reported by us previously. However, this linear structure was found to be at the local energy minimum (stable) in water but at a metastable intermediate state (higher energy) in chloroform. Therefore, it could be said that the water solvent can be successfully used for folding simulations of peptaibols. Full article

Peptaibols are proteolysis-resistant, membrane-active peptides. Their remarkably stable helical 3D-structures are key for their bioactivity. They can insert themselves into the lipid bilayer as barrel staves, or lay on its surface like carpets, depending on both their length and the thickness of the lipid bilayer. Medium-length peptaibols are of particular interest for studying the peptide–membrane interaction because their length allows them to adopt either orientation as a function of the membrane thickness, which, in turn, might even result in an enhanced selectivity. Electron paramagnetic resonance (EPR) is the election technique used to this aim, but it requires the synthesis of spin-labeled medium-length peptaibols, which, in turn, is hampered by the poor reactivity of the C^α-tetrasubstituted residues featured in their sequences. After several years of trial and error, we are now able to give state-of-the-art advice for a successful synthesis of nitroxide-containing peptaibols, avoiding deleted sequences, side reactions and difficult purification steps. Herein, we describe our strategy and itsapplication to the synthesis of spin-labeled analogs of the recently discovered, natural, medium-length peptaibol pentadecaibin. We studied the antitumor activity of pentadecaibin and its analogs, finding potent cytotoxicity against human triple-negative breast cancer and ovarian cancer. Finally, our analysis of the peptide conformational preferences and membrane interaction proved that pentadecaibinspin-labeling does not alter the biological features of the native sequence and is suitable for further EPR studies. The nitroxide-containing pentadecaibins, and their synthetic strategy described herein, will help to shed light on the mechanism of the peptide–membrane interaction of medium-length peptaibols. Full article

New classes of antibacterial drugs are urgently needed to address the global issue of antibiotic resistance. In this context, peptaibols are promising membrane-active peptides since they are not involved in innate immunity and their antimicrobial activity does not involve specific cellular targets, therefore reducing the chance of bacterial resistance development. Trichogin GA IV is a nonhemolytic, natural, short-length peptaibol active against Gram-positive bacteria and resistant to proteolysis. In this work, we report on the antibacterial activity of cationic trichogin analogs. Several peptides appear non-hemolytic and strongly active against many clinically relevant bacterial species, including antibiotic-resistant clinical isolates, such as Staphylococcus aureus, Acinetobacter baumannii, and extensively drug-resistant Pseudomonas aeruginosa, against which there are only a limited number of antibiotics under development. Our results further highlight how the modification of natural peptides is a valuable strategy for obtaining improved antibacterial agents with potential therapeutic applications. Full article

Peptaibols (Paib) are a class of biologically active peptides isolated from fungi and molds, which have attracted the attention of medicinal chemists due to their widely ranging pharmacological properties, including their antimicrobial activity. In the present study, we investigated the effects of various pH levels and cultivation conditions on peptaibol complex emericellipsins A-E (EmiA-E), produced by the alkaliphilic fungus Emericellopsis alkalina. Paib production has been studied in flasks and bioreactors for different pH values ranging from 7 to 11. The study of morphological features based on light and scanning electron microscopy has revealed differences between fungi grown at different pH values and cultivation conditions. Emericellipsins have been purified, sequenced, and identified by mass spectrometry. We have found that an alkaline pH of 10 could promote emericellipsins’ biosynthesis most effectively during stationary fermentation on the 14th day of cultivation. Full article

In the large field of bioactive peptides, peptaibols represent a unique class of compounds. They are membrane-active peptides, produced by fungi of the genus Trichoderma and known to elicit plant defenses. Among the short-length peptaibols, trichogin GA IV is nonhemolytic, proteolysis-resistant, antibacterial, and cytotoxic. Several trichogin analogs are endowed with potent activity against phytopathogens, thus representing a sustainable alternative to copper for plant protection. In this work, we tested the activity of trichogin analogs against a breast cancer cell line and a normal cell line of the same derivation. Lys-containing trichogins showed an IC₅₀ below 12 µM, a peptide concentration not significantly affecting the viability of normal cells. Two analogs were found to be membrane-active but noncytotoxic. They were anchored to gold nanoparticles (GNPs) and further investigated for their ability to act as targeting agents. GNP uptake by cancer cells increased with peptide decoration, while it decreased in the corresponding normal epithelial cells. This work highlights the promising biological properties of peptaibol analogs in the field of cancer therapy either as cytotoxic molecules or as active targeting agents in drug delivery. Full article

Black rot caused by the Gram-negative bacterial pathogen Xanthomonas campestris pv. campestris (Xcc) is considered one of the most destructive diseases affecting crucifers. Xcc is a seedborne pathogen able to infect the host at any growth stage. The management of the pathogen mainly relies on the use of copper-based products with possible negative effects on human health and the environment. Searching for protection alternatives is crucial for achieving a sustainable management of Xcc. Trichoderma spp. has been largely used as a biocontrol agent against several phytopathogens. Among Trichoderma species, Trichoderma longibrachiatum produces the peptaibol trichogin GA IV, a secondary metabolite with antimicrobial activity against Gram-positive bacteria, as well as filamentous and yeast-like fungi. In this work, we tested, at micromolar concentrations, 25 synthetic analogs of the peptaibol trichogin GA IV for their bacteriostatic and bactericidal activity toward the bacterium Xcc. One of the most effective peptides (4r) was also tested against the Gram-negative bacteria Xanthomonas arboricola, Pseudomonas corrugata, Pseudomonas savastanoi pv. savastanoi, Agrobacterium tumefaciens, Ralstonia solanacearum, and Erwinia carotovora subsp. carotovora, as well as the Gram-positive bacterium Bacillus subtilis. The peptide 4r reduced black rot symptoms on cauliflower plants when administered both before and 24 h after inoculation with Xcc. The cytotoxic activity of the peptide 4r was also evaluated towards suspensions of tobacco cells by Evans Blue assay. Full article

Trichoderma is recognized as a prolific producer of nonribosomal peptides (NRPs) known as peptaibols, which have remarkable biological properties, such as antimicrobial and anticancer activities, as well as the ability to promote systemic resistance in plants against pathogens. In this study, the sequencing of 11-, 14- and 15-res peptaibols produced by a marine strain of Trichoderma isolated from the ascidian Botrylloides giganteus was performed via liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-MS/MS). Identification, based on multilocus phylogeny, revealed that our isolate belongs to the species T. endophyticum, which has never been reported in marine environments. Through genome sequencing and genome mining, 53 biosynthetic gene clusters (BGCs) were identified as being related to bioactive natural products, including two NRP-synthetases: one responsible for the biosynthesis of 11- and 14-res peptaibols, and another for the biosynthesis of 15-res. Substrate prediction, based on phylogeny of the adenylation domains in combination with molecular networking, permitted extensive annotation of the mass spectra related to two new series of 15-res peptaibols, which are referred to herein as “endophytins”. The analyses of synteny revealed that the origin of the 15-module peptaibol synthetase is related to 18, 19 and 20-module peptaibol synthetases, and suggests that the loss of modules may be a mechanism used by Trichoderma species for peptaibol diversification. This study demonstrates the importance of combining genome mining techniques, mass spectrometry analysis and molecular networks for the discovery of new natural products. Full article

Peptaibols (P_aib), are a class of biologically active peptides isolated from soil, fungi and molds, which have interesting properties as antimicrobial agents. P_aib production was optimized in flasks by adding sucrose as a carbon source, 2-aminoisobutyric acid (Aib) as an additive amino acid, and F. oxysporum cell debris as an elicitor. P_aib were purified, sequenced and identified by High-performance liquid chromatography (HPLC)coupled to mass spectrometry. Afterward, a P_aib extract was obtained from the optimized fermentations. The biological activity of these extracts was evaluated using in vitro and in vivo methods. The extract inhibited the growth of specific plant pathogens, and it showed inhibition rates similar to those from commercially available fungicides. Growth inhibition rates were 92.2, 74.2, 58.4 and 36.2% against Colletotrichum gloeosporioides, Botrytis cinerea, Alternaria alternata and Fusarium oxysporum, respectively. Furthermore, the antifungal activity was tested in tomatoes inoculated with A. alternata, the incidence of the disease in tomatoes treated with the extract was 0%, while the untreated fruit showed a 92.5% incidence of infection Scanning electron microscopy images showed structural differences between the fungi treated with or without P_aib. The most visual alterations were sunk and shriveled morphology in spores, while the hyphae appeared to be fractured, rough and dehydrated. Full article

Features of the biochemical adaptations of alkaliphilic fungi to exist in extreme environments could promote the production of active antibiotic compounds with the potential to control microorganisms, causing infections associated with health care. Thirty-eight alkaliphilic and alkalitolerant Emericellopsis strains (E. alkalina, E. cf. maritima, E. cf. terricola, Emericellopsis sp.) isolated from different saline soda soils and belonging to marine, terrestrial, and soda soil ecological clades were investigated for emericellipsin A (EmiA) biosynthesis, an antifungal peptaibol previously described for Emericellopsis alkalina. The analysis of the Emericellopsis sp. strains belonging to marine and terrestrial clades from chloride soils revealed another novel form with a mass of 1032.7 Da, defined by MALDI-TOF Ms/Ms spectrometers, as the EmiA lacked a hydroxyl (dEmiA). EmiA displayed strong inhibitory effects on cell proliferation and viability of HCT 116 cells in a dose- and time-dependent manners and induced apoptosis. Full article

Fungal species of genus Sepedonium are rich sources of diverse secondary metabolites (e.g., alkaloids, peptaibols), which exhibit variable biological activities. Herein, two new peptaibols, named ampullosporin F (1) and ampullosporin G (2), together with five known compounds, ampullosporin A (3), peptaibolin (4), chrysosporide (5), c(Trp-Ser) (6) and c(Trp-Ala) (7), have been isolated from the culture of Sepedonium ampullosporum Damon strain KSH534. The structures of 1 and 2 were elucidated based on ESI-HRMSⁿ experiments and intense 1D and 2D NMR analyses. The sequence of ampullosporin F (1) was determined to be Ac-Trp¹-Ala²-Aib³-Aib⁴-Leu⁵-Aib⁶-Gln⁷-Aib⁸-Aib⁹-Aib¹⁰-GluOMe¹¹-Leu¹²-Aib¹³-Gln¹⁴-Leuol¹⁵, while ampullosporin G (2) differs from 1 by exchanging the position of Gln⁷ with GluOMe¹¹. Furthermore, the total synthesis of 1 and 2 was carried out on solid-phase to confirm the absolute configuration of all chiral amino acids as L. In addition, ampullosporin F (1) and G (2) showed significant antifungal activity against B. cinerea and P. infestans, but were inactive against S. tritici. Cell viability assays using human prostate (PC-3) and colorectal (HT-29) cancer cells confirmed potent anticancer activities of 1 and 2. Furthermore, a molecular docking study was performed in silico as an attempt to explain the structure-activity correlation of the characteristic ampullosporins (1–3). Full article