Search Results (319)

Locusta migratoria manilensis (Meyen) is a highly destructive insect pest worldwide. However, excessive reliance on insecticides has resulted in significant environmental pollution. Biocontrol complexes combine two or more BCAs to address the limitations of individual agents. However, biocontrol complex for locust control has been rarely reported. Here, we propose BioControl 3.0, which integrates Metarhizium anisopliae var. acridum (Driver and Milner) and Carabus smaragdinus (Fischer von Waldheim) for locust control. We evaluated this system through a series of laboratory bioassays and semi-field cage experiments, comparing single-agent applications, sequential combinations (BioControl 2.0), and predator-mediated delivery (BioControl 3.0), and quantified locust mortality and interaction effects between predation and infection We found that M. anisopliae caused >85% mortality of locust nymphs at 1 × 10⁸ conidia/mL (LT₅₀ ≈ 6 days) while exhibiting negligible virulence toward C. smaragdinus. BioControl 2.0 (sequential application) increased mortality compared to single agents. However, this approach revealed a significant negative interaction between predation and infection, which limited the total control efficacy. BioControl 3.0 (predator-vectored fungus) achieved the highest corrected mortality, with predation and infection acting independently and additively (no detectable antagonistic interaction). By leveraging a predatory vector, BioControl 3.0 decouples negative interaction and harnesses dual biotic pressures, offering a cost-effective, environmentally benign alternative to conventional locust control. Our findings provide a blueprint for designing integrated predator-pathogen complexes and optimizing deployment strategies for sustainable management of locust outbreaks. Full article

A growing body of evidence indicates that artificial manipulation of transcriptional regulation is a powerful approach to activate cryptic biosynthetic gene clusters (BGCs) of secondary metabolites (SMs) in fungi. In this study, one mutant strain MNP-2-OE::veA was constructed by overexpressing the global transcription regulator veA in an Arctic-derived strain Aspergillus sydowii MNP-2. Chemical investigation of the mutant OE::veA resulted in the isolation of one novel polyhydroxy anthraquinone (1) together with nine known metabolites (2–10), which were unambiguously characterized by various spectroscopic methods including 1D and 2D NMR and HR-ESI-MS as well as via comparison with literature data. Biosynthetically, compounds 1 and 10 as new arising chemicals were, respectively, formed by type II polyketide synthase (T2PK) and non-ribosomal peptide synthetase (NRPS), which were silent in the wild-type (WT) strain MNP-2. A bioassay showed that only compound 3 had weak inhibitory effect on human pathogen Candida albicans, with a MIC value of 64 ug/mL, and 4 displayed in vitro weak cytotoxic activity against HCT116 cells (IC₅₀ = 44.47 μM). These results indicate that overexpression of veA effectively awakened the cryptic BGCs in fungal strains and enhanced their structural diversity in natural products. Full article

The infestation of Echinochloa crus-galli (L.) P.Beauv. in crop fields results in significant yield loss in many agricultural systems. Currently, the most effective strategy for controlling E. crus-galli is the application of synthetic herbicides. However, biotypes of E. crus-galli that are resistant to different modes of herbicide action often emerge. Thus, it is necessary to develop alternative control methods and address ecological concerns about synthetic herbicides. During the field survey, we observed diseased E. crus-galli exhibiting symptoms of leaf blight. These symptoms indicate a potential pathogen infection and subsequent phytotoxin production during the pathogenesis. Therefore, we aimed to isolate and identify the phytotoxic substances present in the diseased leaves. Aqueous extracts of the diseased leaves exhibited phytotoxicity, suppressing the growth of Echinochloa crus-galli seedlings in a concentration-dependent manner. A phytotoxic substance was isolated from the leaf extracts through a bioassay-guided separation process using the E. crus-galli bioassay. Spectrum analysis revealed that the phytotoxic substance was monocerin. Monocerin inhibited the growth of coleoptiles and roots of E. crus-galli seedlings at concentrations greater than 30 and 10 μM, respectively, and inhibited germination at concentrations greater than 100 μM. Therefore, monocerin may be involved in the phytotoxic activity exhibited by the extracts of E. crus-galli leaves with blight symptoms. Creating bioherbicides based on the monocerin structure could be an environmentally friendly approach to weed management. Full article

Terminalia catappa L. (Family: Combretaceae) is used globally to treat various diseases, including bacterial infections. Whilst the antibacterial activity of T. catappa has previously been tested against antibiotic-sensitive bacterial strains, the antimicrobial activity against methicillin and β-lactam-resistant pathogens has been relatively ignored. The antibacterial activity of T. catappa extracts, both alone and combined with selected clinical antibiotics, was evaluated in this study. The inhibition of bacterial growth by the extracts was determined using agar diffusion and broth micro-dilution assays. Combinations of the extracts and several clinical antibiotics were also examined and the ∑FICs were calculated to determine the interaction class. Synergistic combinations were further evaluated by isobologram analysis. The T. catappa leaf extracts were screened for toxicity using Artemia franciscana lethality bioassays (ALA). Orbitrap liquid chromatography–mass spectrometry (LC-MS) profiling analysis was undertaken to identify flavonoid components of the extracts, putatively. The T. catappa methanolic extract inhibited all the tested bacterial strains. It displayed especially good inhibitory activity against E. coli (MIC = 130 µg/mL). Combining the T. catappa extracts with some conventional antibiotics potentiated the inhibitory activity of the combinations compared to the activity of individual components. LC-MS profiling analysis identified multiple flavonoid components, including rutin, quercitin, orientin, the tannin component, and ellagic acid in the extracts. All extracts were non-toxic against Artemia nauplii. The phytochemical constituents present in the T. catappa leaf extracts warrant future investigation as potential antibacterial agents. Full article

Phytoptus avellanae is a key hazelnut pest, causing the swelling of mixed buds during the autumn–winter period and a compromised nut yield. This study aimed to evaluate the effectiveness of commercial biopesticides based on Beauveria bassiana and Akanthomyces muscarius in controlling this pest. Specific laboratory and field protocols were developed. In the laboratory, bud galls were disinfected, dissected, immersed for 30 s in a water suspension of the products and in water (control), dried in a laminar flow hood, incubated for 7 days and inspected to assess mite mortality. Intermediate observations were also recorded. Significantly higher mortality was recorded in the treatment with B. bassiana. Infection with B. bassiana was confirmed by a culture in medium and slide-mounting of infected mites. The orchard assay was performed by immersing buds and nuts in the fungal suspensions applied in the laboratory without separating any organ from the plant. Two weeks after application, the treated plant organs were removed and examined to assess mite mortality. The organs treated with B. bassiana showed higher mite mortality than the control for both buds and nuts. Treatments with arthropod pathogenic fungi appear to be promising for inclusion in the control strategy of P. avellanae. Full article

Crown gall disease, caused by soil-borne bacterial pathogens, such as Allorhizobium vitis, poses a significant threat to grapevine cultivation in Japan, particularly under environmental conditions exacerbated by climate change. Effective chemical control options are limited, highlighting the need for sustainable biocontrol strategies. In this study, we screened a library of soil bacteria with known antagonistic activity against major grapevine fungal pathogens and identified Pseudomonas sp. strain YU44 as a broad-spectrum antagonist of crown gall pathogens A. vitis and Rhizobium radiobacter. In vitro assays demonstrated that YU44 inhibits the growth of both pathogens by secreting bioactive compounds. In vivo bioassays confirmed that pretreatment with YU44 significantly suppresses crown gall formation in grapevine and rose seedlings. Additionally, YU44 application to soil near the stem base reduces disease severity in grapevine seedlings, supporting its potential as a practical biocontrol agent. Although complete disease suppression is not achieved, YU44 represents a promising environmentally friendly alternative for integrated disease management because it can complement resistant rootstocks, sanitation practices, and cultivation methods. These findings highlight YU44’s potential as an adaptive management tool for crown gall disease in the face of climate change. Full article

Plant fungal diseases pose a serious threat to crop production and safety, and natural products are one of the important directions for the development of new green fungicides. This study found that the extract of Murraya euchristifolia had significant antifungal activity, and a main antifungal coumarin (1) was isolated by bioassay-guided fractionation. The structure of 1 was identified by NMR and MS spectroscopic data as a fused bis-furan coumarin (microminutinin) which was first isolated from the Murraya genus and exhibited strong broad-spectrum antifungal activity against eight plant pathogenic fungi from different families and genera. The EC₅₀ value of 1 (11.33 μg/mL) against Pestalotiopsis theae (the most sensitive to 1) was slightly higher than that (7.03 μg/mL) of the positive drug (80% carbendazim WP), indicating that 1 has the potential to serve as a lead compound for botanical fungicides. The bioassay results against P. theae in vivo indicated that 1 also has the potential for field application. Scanning electron microscopy and optical microscopy revealed that 1 disrupted the morphological structure of mycelium, causing hyphae to twist, shrink, and even crack and severely reducing hyphal branching. Furthermore, propidium iodide staining proved that microminutinin destroyed the integrity of the cell membrane, causing leakage of cellular components. In addition, calcofluor white staining and chitin content changes illustrated that microminutinin disrupted the cell wall structure. This research provides compound sources and a theoretical basis for the development of botanical fungicides. Full article

House flies (Musca domestica L.) are major vectors of numerous pathogens affecting both humans and animals. The global distribution of house flies has been steadily increasing the expansion of human settlements, increased waste production, and the growth of livestock farms established to meet the demand for animal-derived products. Frequent exposure to intensive pesticide applications in agricultural and livestock areas has accelerated the development of insecticide resistance, posing a serious challenge to sustainable control efforts. The widespread and repeated use of conventional chemical insecticides has contributed to rapid resistance evolution in many populations worldwide. In this study, the acute toxic effects of two insect growth regulators (IGRs)—cyromazine and methoprene—commonly used in the larval stages of house flies were evaluated against adult flies. Treatments were applied (3 replicates) orally via 40% sugar-water solutions containing 1%, 5%, and 10% concentrations, and bioassays were conducted on eight distinct house fly populations. The results showed that cyromazine caused average adult mortalities of 76.35%, 81.00%, and 84.50% within 48 h, while methoprene produced 70.62%, 99.37%, and 100% mortality at the same concentrations. At 10%, methoprene achieved 100% mortality across all populations, whereas cyromazine induced mortality ranging from 44.28% to 100%. These findings suggest that IGRs can be effective alternatives to conventional insecticides and can be integrated into IPM/IVM programs to reduce chemical use and delay resistance. Full article

Francisella tularensis is a pathogenic bacterium and the causative agent of the disease tularemia. Because of the virulence of this bacterium and the potential for weaponization, the Centers for Disease Control and Prevention (CDC) has classified F. tularensis as a Category A Bioterrorism Agent. Therefore, the need for new treatments for tularemia is critical. In this work, we screened a cataloged library of natural extracts to identify those that inhibit the growth of F. tularensis only during infection of THP-1 monocyte cells. One of the most promising extracts identified in this screen was derived from Foeniculum vulgare (fennel). Using bioassay-guided fractionation, the fennel extract was fractionated, and the bioactive compound was isolated and structurally elucidated as the phenylpropanoid dillapiole. We subsequently confirmed that dillapiole alone could limit the replication of F. tularensis in infected THP-1 cells, but not outside of this infection model. Investigations on host responses suggested that dillapiole was not substantially augmenting the immunity of these THP-1 cells. We then investigated the potential virulence modulation activity of dillapiole. To test this hypothesis, RNA-seq analysis was carried out on F. tularensis bacteria that were treated with dillapiole. This showed that dillapiole caused a significant downregulation of genes controlled by the transcriptional regulators MglA and SspA, including those encoded in the Francisella pathogenicity island. Western blotting validated these findings as both IglA and IglC expression was diminished in F. tularensis LVS bacteria treated with dillapiole. Because dillapiole dampens the virulence gene expression of F. tularensis, we concluded that this compound has potential to be used as a novel therapeutic for tularemia with a unique mechanism of action. Full article

The black bug, Antiteuchus tripterus (Hemiptera: Pentatomidae), is one of the most important pests of cacao in Peru. Its control relies primarily on synthetic insecticides, which negatively impact the environment and the health of cacao farmers. Therefore, the use of natural enemies, such as entomopathogenic fungi, represents a promising and sustainable alternative. In this study, we aimed to characterize entomopathogenic fungal isolates obtained from naturally infected A. tripterus adults in Peru. Using morphological and molecular approaches, we identified the isolates as Purpureocillium takamizusanense. Then, we assessed their pathogenic potential against A. tripterus and identified their functional cell wall groups. To evaluate pathogenicity, A. tripterus nymphs were exposed to serially diluted conidial suspensions (10⁵–10⁹ conidia mL⁻¹; isolate 24M) in both laboratory and field trials. The isolates exhibited conidial viability above 99%. Concentration-mortality bioassays confirmed the lethal effect of P. takamizusanense against A. tripterus nymphs. The LC₅₀ was 1.65 × 10⁶ conidia mL^–1, while the LT₅₀ and LT₉₀ were 3.08 and 7.29 days, respectively. The field mortality rate was about 52%, which can be explained by the influence of the environment. Spectroscopy analyses revealed functional groups including chitin, glucans, lipids, aliphatic chains, and proteins, which may contribute to infection and fungal persistence. This study presents the first record of P. takamizusanense in the Americas and highlights its potential as a biocontrol agent against A. tripterus in cacao plantations. Full article

Three previously undescribed clerodane diterpenoids, including two cis-clerodanes, solidagolactone IX (1) and solidagoic acid K (2), and one trans-clerodane, solidagodiol (3), along with two known cis-clerodane diterpenoids, (−)-(5R,8R,9R,10S)-15,16-epoxy-ent-neo-cleroda-3,13,14-trien-18-ol (4) and solidagoic acid J (5), were isolated and comprehensively characterized from the ethanolic and ethyl acetate root extract of Solidago gigantea Ait. (giant goldenrod). Compound 4 has previously been reported from the roots of this species, whereas compound 5 was identified from the leaves of S. gigantea but not from the roots. The bioassay-guided isolation involved thin-layer chromatography–direct bioautography (TLC–DB) with a Bacillus subtilis antibacterial assay, preparative flash column chromatography, and TLC–mass spectrometry (MS). The chemical structures of the isolated compounds (1–5) were elucidated through extensive in-depth spectroscopic and spectrometric analyses, including one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy, high-resolution tandem mass spectrometry (HRMS/MS), and attenuated total reflectance Fourier-transform infrared (ATR–FTIR) spectroscopy. Their antimicrobial activities were evaluated using in vitro microdilution assays against B. subtilis and different plant pathogens. Compound 3 was the most active against the tested Gram-positive strains, exerting particularly potent effects against Clavibacter michiganensis with a minimal inhibitory concentration (MIC) value of 5.1 µM as well as B. subtilis and Curtobacterium flaccumfaciens pv. flaccumfaciens (MIC 21 µM for both). Compound 4 also strongly inhibited the growth of C. michiganensis (MIC 6.3 µM). Compounds 2, 4, and 5 displayed moderate to weak activity against B. subtilis and C. flaccumfaciens pv. flaccumfaciens with MIC values ranging from 100 to 402 µM. Rhodococcus fascians bacteria were moderately inhibited by compounds 3 (MIC 41 µM) and 4 (MIC 201 µM). Bactericidal activity was observed for compound 3 against C. michiganensis with a minimal bactericidal concentration (MBC) value of 83 µM. Compounds 2 and 3 demonstrated weak antifungal activity against Fusarium graminearum. Our findings underscore the value of bioassay-guided approaches in discovering previously undescribed bioactive compounds. Full article

Using the one-strain-many-compounds (OSMAC) culturing approach, metabolomic studies, and bioassay-guided purification, we have isolated and characterised three new chlorinated natural products, agelolines B-D (1–3), together with two known compounds, ageloline A (4) and gausemycin A (5), which have been identified by high-resolution mass spectrometry and 1D and 2D NMR analyses. The preliminary evaluation of three small-scale extracts (M400, R358 and SGG) against the fish pathogen, Aeromonas salmonicida subsp. achromogenes KELDUR265-87, showed that the R358 extract displayed significant activity. Furthermore, the natural products (1–5) were evaluated against the fish pathogen Aeromonas salmonicida and human pathogens (Stenotrophomonas maltophilia L2125, Staphylococcus aureus ATCC6538P, and S. pneumoniae L44) using a serial dilution assay. Compound 3 displayed activity against Staphylococcus aureus ATCC6538P, S. maltophilia L2125, and S. pneumoniae L44 with MIC values of 6, 32, and 64 µg/mL, respectively. Interestingly, only gausemycin A (5) exhibited considerable inhibition against A. salmonicida with an MIC value of 32 µg/mL, and the activity increased by two-fold when supplemented with 0.45 mM calcium salt, while 2 and 4 showed moderate inhibition against S. maltophilia L2125. The biosynthetic pathways of compounds 1–4 were proposed. This is the first report of specific inhibition of A. salmonicida by 5. Full article

With the goal of bioprospecting for growth-promoting endophytes that could become yield-enhancing inoculants in maize agriculture, we isolated 129 endophytic bacteria from 22 wild plants growing in a nature preserve and an urban park in Cali, Colombia. These strains were put through a bioassay with surface-sterilized seeds of perennial ryegrass (Lolium perenne) grown in sealed tubes, and growth promotion assessed by measuring plant fresh weight. The top two strains Pseudomonas delhiensis and Serratia marcescens, along with five different subcultured root endophytic communities, were put into a secondary screen along with two uninoculated controls of untreated and surface-sterilized seed of both the turfgrass and a commercial maize hybrid. Impact on plant microbiomes was assessed using molecular fingerprinting and high-throughput sequencing. This second bioassay indicated that plant growth promotion was corelated not with inoculation but with seed surface sterilization which shifted root microbiomes, increased endophyte diversity and probably eliminated pathogens. Inoculating maize (but not ryegrass) seed with either pure bacteria or microbial communities was also able to shift the root microbiome. Because the majority of plant microbiome researchers employ seed surface sterilization as a method to standardize their experiments, they could be inadvertently studying unusual plant phenotypes and microbiomes; a possible reason why field trials correlate poorly with those of lab tests. Full article

Despite significant medical advancements, two major health challenges persist: antibiotic resistance in microbial pathogens and drug resistance in cancer cells. To address these issues, research has increasingly focused on discovering novel natural compounds with dual antimicrobial and anticancer activities. Among such candidates, antimicrobial peptides (AMPs) have attracted attention due to their ability to selectively target microbial and cancer cells while exhibiting minimal toxicity toward normal cells. Although Vietnam possesses rich biodiversity, including a wide range of Anura species, studies on AMPs from these organisms remain limited. In this study, a novel AMP, brevinin-1 E8.13, was identified from the skin secretion of Sylvirana guentheri, a frog species native to Vietnam. The brevinin-1 E8.13 peptide was successfully cloned, sequenced, and chemically synthesized. Functional assays revealed that brevinin-1 E8.13 possesses strong antibacterial activity against Staphylococcus aureus and exerts significant antiproliferative effects on various human cancer cell lines, including A549 (lung), AGS (gastric), Jurkat (leukemia), HCT116 (colorectal), HL60 (leukemia), and HepG2 (liver). The peptide demonstrated moderate to potent cytotoxic activity, with IC₅₀ values ranging from 7.5 to 14.8 μM, depending on the cell type. Notably, brevinin-1 E8.13 exhibited low cytotoxicity toward normal human dermal fibroblast (HDF) cells and even promoted cell proliferation at lower concentrations. Furthermore, Chemically Activated Fluorescent Expression (CAFLUX) bioassay results confirmed that the peptide significantly downregulated Cyp1a1 gene expression in HepG2 cells. Collectively, these findings highlight the therapeutic potential of brevinin-1 E8.13 as a dual-function antimicrobial and anticancer agent derived from the skin secretion of Sylvirana guentheri. Full article

(1) Background: Tolypocladium spp. are fungi known for producing cyclosporin A and their ability to infect insects. However, their pathogenicity against the lepidopteran pest Plutella xylostella has not been previously reported. (2) Methods: Four Tolypocladium strains were isolated from soil and identified through morphological and phylogenetic analyses (ITS, gene sequencing). Growth rates, sporulation capacity, and stress tolerance (45 °C heat, UV) were evaluated. Pathogenicity was assessed via larval bioassays, and immune responses were analyzed by quantifying Toll pathway gene expression and enzyme activities (PO, CAT, POD, GSTs, CarE, AChE) from 24 to 96 h post-inoculation. (3) Results: Strains N8-SF-04092 and O1/O2/O3-SF-04630/04927/04931 were identified as Tolypocladium cylindrosporum and Tolypocladium inflatum, respectively. Strain O2 showed the highest growth rate (p < 0.05), while O3 and N8 exhibited superior sporulation (>7 × 10⁵ spores/mm²). N8 also demonstrated notable thermotolerance. In pathogenicity assays, O1, O3, and N8 caused 98.3%, 93.3%, and 96.7% larval mortality, respectively, with LT₅₀ values (3.89–4.45 days) significantly lower than O2 (p < 0.05). Immune gene expression in P. xylostella was transiently activated at 24 h but suppressed from 48 to 96 h by N8 (p < 0.05), while O1 induced partial activation at 24 h and 96 h but suppression at 48 h and 72 h. Protective enzymes (PO, CAT) were initially upregulated (24–48 h) but inhibited after 72 h (p < 0.01). POD activity showed opposing trends between O1 (initially activated then suppressed) and N8 (initially suppressed then activated). Detoxification enzymes (GSTs, CarE, AchE) were predominantly suppressed, except for GSTs, which increased at 72–96 h. (4) Conclusions: Strains O1 and N8 exhibit high virulence against P. xylostella by disrupting immune responses through dynamic modulation of Toll pathway genes and enzyme activities. The thermotolerance of strain N8 further enhances its promising biocontrol agent for field application. Full article