Nematocidal Activity Research Articles

Defense Molecules of the Invasive Plant Species Ageratum conyzoides

Ageratum conyzoides L. is native to Tropical America, and it has naturalized in many other tropical, subtropical, and temperate countries in South America, Central and Southern Africa, South and East Asia, Eastern Austria, and Europe. The population of the species has increased dramatically as an invasive alien species, and it causes significant problems in agriculture and natural ecosystems. The life history traits of Ageratum conyzoides, such as its short life cycle, early reproductive maturity, prolific seed production, and high adaptive ability to various environmental conditions, may contribute to its naturalization and increasing population. Possible evidence of the molecules involved in the defense of Ageratum conyzoides against its natural enemies, such as herbivore insects and fungal pathogens, and the allelochemicals involved in its competitive ability against neighboring plant species has been accumulated in the literature. The volatiles, essential oils, extracts, residues, and/or rhizosphere soil of Ageratum conyzoides show insecticidal, fungicidal, nematocidal, and allelopathic activity. The pyrrolizidine alkaloids lycopsamine and echinatine, found in the species, are highly toxic and show insecticidal activity. Benzopyran derivatives precocenes I and II show inhibitory activity against insect juvenile hormone biosynthesis and trichothecene mycotoxin biosynthesis. A mixture of volatiles emitted from Ageratum conyzoides, such as β-caryophyllene, β-bisabolene, and β-farnesene, may work as herbivore-induced plant volatiles, which are involved in the indirect defense function against herbivore insects. Flavonoids, such as nobiletin, eupalestin, 5′-methoxynobiletin, 5,6,7,3′,4′,5′-hexamethoxyflavone, and 5,6,8,3,4′,5′-hexamethoxyflavone, show inhibitory activity against the spore germination of pathogenic fungi. The benzoic acid and cinnamic acid derivatives found in the species, such as protocatechuic acid, gallic acid, p-coumaric acid, p-hydroxybenzoic acid, and ferulic acid, may act as allelopathic agents, causing the germination and growth inhibition of competitive plant species. These molecules produced by Ageratum conyzoides may act as defense molecules against its natural enemies and as allelochemicals against neighboring plant species, and they may contribute to the naturalization of the increasing population of Ageratum conyzoides in new habitats as an invasive plant species. This article presents the first review focusing on the defense function and allelopathy of Ageratum conyzoides.

Paenibacillus polymyxa J2-4 induces cucumber to enrich rhizospheric Pseudomonas and contributes to Meloidogyne incognita management under field conditions.

Root knot nematodes (RKNs) pose a great threat to agricultural production worldwide. The bacterial nematocides have received increasing attention due to their safe and efficient control against RKNs. Here, we investigated the biocontrol efficacy of Paenibacillus polymyxa J2-4 against Meloidogyne incognita in the field and analyzed the rhizosphere microbiome of cucumber under nematode infection after application of the J2-4 strain. Furthermore, a biomarker strain of Pseudomonas spp. was isolated from the J2-4-inoculated rhizosphere soil, and its nematocidal activity and growth-promoting effect on host plants were determined. In addition, chemotaxis assay of P. fluroescens ZJ5 toward root exudates was carried out. The field experiment demonstrated that P. polymyxa J2-4 could effectively suppressed gall formation in cucumber plants, with the galling index reduced by 67.63% in 2022 and 65.50% in 2023, respectively, compared with controls. Meanwhile, plant height and yield were significantly increased in J2-4 treated plants compared with controls. Metagenomic analysis indicated that J2-4 altered the rhizosphere microbial communities. The relative abundance of Pseudomonas spp. was notably enhanced in the J2-4 group, which was consistent with Linear discriminant analysis Effect Size results that Pseudomonas was determined as one of the biomarkers in the J2-4 group. Furthermore, the ZJ5 strain, one of the biomarker Pseudomonas strains, was isolated from the J2-4-inoculated rhizosphere soil and was identified as Pseudomonas fluorescens. In addition, P. fluorescens ZJ5 exhibited high nematicidal activity in vitro and in vivo, with 99.20% of the mortality rate of M. incognita at 24 h and 69.75% of gall index reduction. The biocontrol efficiency of the synthetic community of ZJ5 plus J2-4 was superior to that of any other single bacteria against M. incognita. Additionally, ZJ5 exhibited great chemotaxis ability toward root exudates inoculated with J2-4. Paenibacillus polymyxa J2-4 has good potential in the biological control against M. incognita under field conditions. Enrichment of the beneficial bacteria Pseudomonas fluorescens ZJ5 in the J2-4-inoculated rhizosphere soil contributes to M. incognita management. © 2024 Society of Chemical Industry.

Pepper root exudate alleviates cucumber root-knot nematode infection by recruiting a rhizobacterium

Root-knot nematodes (Meloidogyne spp.) have garnered significant attention from researchers due to their substantial damage to crops and worldwide distribution. However, controlling this nematode disease is challenging which results from limited chemical pesticides and biocontrol agents effective against them. Here, we demonstrate that pepper-rotation markedly reduces Meloidogyne incognita infection in cucumber and diminishes the presence of p-hydroxybenzoic acid in the soil, a compound known to exacerbate M. incognita infection. Pepper-rotation also structures the rhizobacterial community, leading to the colonization of two Pseudarthrobacter oxydans strains (RH60 and RH97) in the cucumber rhizosphere, facilitated by palmitic acid enrichment in pepper root exudates. Furthermore, both strains exhibit high nematocidal activity against M. incognita, and possess the ability to biosynthesize indoleacetic acid and biodegrade p-hydroxybenzoic acid. RH60 and RH97 additionally induce systemic resistance in cucumber plants and promote their growth. These data suggest that pepper root-exudate palmitic acid alleviates M. incognita infection by recruiting beneficial P. oxydans in the cucumber rhizosphere. Our analyses identify a novel chemical component in root exudates and uncover its pivotal role in crop rotation for disease attenuation, providing intriguing insights into the keystone function of root exudates in plant protection against root-knot nematode infection.

Correction: Nematocidal activity of chitosan nanoparticles conjugated with albendazole against the enteral and parenteral phases of trichinosis in experimentally infected mice

Correction: Nematocidal activity of chitosan nanoparticles conjugated with albendazole against the enteral and parenteral phases of trichinosis in experimentally infected mice

Design, Synthesis, and Nematocidal Evaluation of Waltherione A Derivatives: Leveraging a Structural Simplification Strategy.

Southern root-knot nematodes are among the most pernicious phytoparasites; they are responsible for substantial yield losses in agricultural crops worldwide. The limited availability of nematicides for the prevention and control of plant-parasitic nematodes necessitates the urgent development of novel nematicides. Natural products have always been a key source for the discovery of pesticides. Waltherione A, an alkaloid, exhibits potent nematocidal activity. In this study, we designed and synthesized a series of quinoline and quinolone derivatives from Waltherione A, leveraging a strategy of structural simplification. Bioassays have revealed that the quinoline derivatives exhibit better activity than quinolone derivatives in terms of both nematocidal and fungicidal activities. Notably, compound D1 demonstrated strong nematocidal activity, with a 72 h LC50 of 23.06 μg/mL, and it effectively controlled the infection of root-knot nematodes on cucumbers. The structure-activity relationship suggests that the quinoline moiety is essential for the nematocidal efficacy of Waltherione A. Additionally, compound D1 exhibited broad-spectrum fungicidal activity, with an EC50 of 2.98 μg/mL against Botrytis cinerea. At a concentration of 200 μg/mL, it significantly inhibited the occurrence of B. cinerea on tomato fruits, with an inhibitory effect of 96.65%, which is slightly better than the positive control (90.30%).

Optimization and Stability Assessment of Monochamus alternatus Antimicrobial Peptide MaltAtt-1 in Komagataella phaffii GS115 for the Control of Pine Wood Nematode.

MaltAtt-1 is an antimicrobial peptide isolated from Monochamus alternatus with nematocidal activity against pine wood nematode. In this study, a eukaryotic expression system based on Komagataella phaffii GS115 was established, and its secretory expression of MaltAtt-1 was realized. The basic properties and secondary and tertiary structures of the antimicrobial peptide MaltAtt-1 were identified by bioinformatics analysis. MaltAtt-1 is a hydrophilic stable protein, mainly composed of an α-helix (Hh), β-folds (Ee), and irregular curls (Cc). The optimal fermentation conditions for MaltAtt-1 were determined by a single-factor test and the Box-Behnken response surface method, including an induction time of 72 h, induction temperature of 30 °C, culture medium of pH 7.6, methanol volume fraction of 2.0%, and an initial glycerol concentration of 1%. The stability of MaltAtt-1 indicated its resistant to UV irradiation and repeated freezing and thawing, but the antibacterial activity decreased significantly under the influence of high temperature and a strong acid and base, and it decreased significantly to 1.1 cm and 0.83 cm at pH 2.0 and pH 10.0, respectively. The corrected mortality of B. xylophilus achieved 71.94% in 3 h at a concentration of 300 mg·L-1 MaltAtt-1 exposure. The results provide a theoretical basis for the antimicrobial peptide MaltAtt-1 to become a new green and efficient nematicide.

Lecanicillium psalliotae (Hypocreales: Cordycipitaceae) Exerts Ovicidal and Larvicidal Effects against the Sheep Blood-Feeding Nematode Haemonchus contortus through Its Liquid Culture Filtrates.

Nematophagous fungi (NF) form part of the soil microbiota and are natural enemies of nematodes, helping to regulate nematode populations. A verticillate NF isolated from soil from Tepalcingo, Mexico, was morphologically and molecularly characterised. This fungus was cultured in two different liquid media-Czapek-Dox broth (CzDoxB) and sweet potato dextrose broth (SPDB)-for 21 days. The ovicidal (OA) and larvicidal (LA) activities of fungal liquid culture filtrates (LCFs) were assessed in 96-well microtitre plates at different concentrations against Haemonchus contortus after 48 h. The morphological and molecular identification revealed the presence of Lecanicillium psalliotae. Additionally, the groups of compounds associated with nematocidal activity were determined from a qualitative chemical profile (QCP) using different reagents. The highest OA of the LCFs was obtained at 25 mg/mL from SPDB and CzDoxB and amounted to 97.2 and 99.06%, respectively. Meanwhile, the highest LA recorded with these LCFs at 100 mg/mL was 54.27% and 96.8%, respectively. The QCP revealed the presence of alkaloids and tannins in both LCFs that have previously been associated with nematocidal activity. Lecanicillium psalliotae exerted an important effect on H. contortus and could be of significance in future studies focused on the control and prevention of haemonchosis in small ruminants.

Arthrobotrys oligospora (Fungi: Orbiliales) and its liquid culture filtrate myco-constituents kill Haemonchus contortus infective larvae (Nematoda: trichostrongylidae)

ABSTRACT Arthrobotrys oligospora is a nematode-trapping fungus belonging to the family Orbiliaceae and one of the main antagonists of nematodes in soil, including plant and animal parasitic nematodes and free-living nematodes. This species develops three-dimensional adhesive nets in which nematodes are trapped, destroyed and consumed by the fungus. It also possesses other strategies to immobilise, kill and degrade nematodes, i.e. nematode-attractant substances, cuticle adhesion polymers and a number of nematocidal metabolites. The objective of this study was to assess the in vitro nematocidal activity of a strain of A. oligospora through its predatory activity and its liquid culture filtrates (LCF) against the ruminant parasite Haemonchus contortus (HcL3) and to investigate the presence of myco-compounds with potential nematocidal activity. Predatory activity (PA) was assessed in agar plates; 200 HcL3 were placed on agar plates with the fungus and a control group and incubated for 10 days. The LCF confrontation with nematodes was performed in microtiter plates. Two media, Czapek-Dox Broth (Cz-DB) and potato dextrose broth, were assessed. Three concentrations (25, 50 and 100 mg/mL) were assessed at 48 and 72 h (n = 4, per concentration). The experiment was performed in triplicate. The results showed 73.6 ± 2.7% PA and the highest mortality (83%) with the LCF in Cz-DB after 72 h. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that the A. oligospora ethyl acetate phase was composed of 1,2-benzenedicarboxylic acid, bis (2-methylpropyl) ester, (M) 1,4-benzenedicarboxylic acid, bis (2-methylpropyl) ester and (M) decanedioic acid (2-ethylexyl) ester. These compounds could be responsible for nematocidal activity.

Nematocidal activity and biocontrol efficacy of endophytic Bacillus velezensis Pt-RP9 from Pinus tabuliformis against pine wilt disease caused by Bursaphelenchus xylophilus

Pine wilt disease (PWD) is a globally significant quarantine forest disease caused by Bursaphelenchus xylophilus (PWN), resulting in substantial ecological and economic losses. Traditional nematode management practices are neither cost-effective nor environmentally friendly, prompting the exploration of biocontrol as a promising alternative for managing this devastating forest disease. Obtaining novel and specific biocontrol agents is extremely crucial for the effective and precise control of PWD. In the present study, a total of 136 endophytic isolates were obtained from the roots, stems and needles of Pinus tabuliformis in the Qinling Mountains of China, which were then subjected to nematocidal activity assay against PWN in vitro. Nine endophytic bacterial isolates exhibited exceptionally strong nematocidal capacity, with a corrected mortality rate exceeding 90 %, which were then identified as the genus of Bacillus through morphological features, endospore staining, and 16S rDNA sequencing, with one strain as B. mycoides, two as B. cereus, and six as B. velezensis. Additionally, the inhibition effects of the three Bacillus species on the reproduction of PWN in vitro was assessed using an original detection model, with B. velezensis Pt-RP9 identified as the most promising strain. Subsequently, the biocontrol efficacy of B. velezensis Pt-RP9 against PWD was evaluated in greenhouse experiments. Pt-RP9 demonstrated significant biocontrol effectiveness against PWD, with control efficiencies ranging from 31.25 % to 68.89 % across all treatments, particularly showing improved efficacy when pine seedlings were pre-treated with Pt-RP9 before PWN inoculation. Furthermore, pine seedlings treated with Pt-RP9 exhibited significantly reduced PWN density and lipid peroxidation levels in cell membranes compared to the control groups, along with increased activities of peroxidase, catalase, and polyphenol oxidase. To our knowledge, this study is the first to showcase the nematocidal activity of endophytes from P. tabuliformis against PWN and their biocontrol efficacy against PWD, marking a significant advancement in the field. The findings highlight the potential of B. velezensis Pt-RP9 as a crucial biological control agent against PWD, presenting a novel and sustainable disease management approach for pine forests.

Hydroalcoholic Extracts from Pleurotus ostreatus Spent Substrate with Nematocidal Activity against Nacobbus aberrans Phytonematode and the Non-Target Species Panagrellus redivivus.

Pleurotus ostreatus, an edible mushroom widely consumed worldwide, generates a by-product known as spent mushroom substrate (SMS). This material has demonstrated biological activity against agricultural crop pathogens. In this study, we evaluated the nematocidal effectiveness of hydroalcoholic extracts (T5, T2, AT5, and AT2) derived from SMS of P. ostreatus against (J2) of the phytonematode Nacobbus aberrans and assessed their potential toxicity towards the non-target nematode Panagrellus redivivus. Among these extracts, AT5 exhibited the highest efficacy against N. aberrans and was the least toxic against P. redivivus. Liquid-liquid partitioning yielded the AQU fraction, which showed significant nematocidal activity against J2 (75.69% ± 8.99 mortality), comparable to chitosan. The GC-MS analysis revealed the presence of several compounds, including palmitic acid, linoleic acid, and 2,4-Di-tert-butylphenol. These findings are consistent with studies confirming the antagonistic effectiveness of these compounds against phytonematodes. Additionally, all extracts exhibited toxicity against P. redivivus, with T2 being the most toxic. Our findings demonstrate that while the AT5 extract displays antagonistic effectiveness against both N. aberrans and P. redivivus, it was the least toxic among the extracts tested. Thus, SMS of P. ostreatus holds potential as a source of nematocidal compounds, which could offer significant benefits for agricultural pest control.

Two new aromatic tenvermectins from mutant Streptomyces avermitilis HU02-06.

Two new aromatic tenvermectins (TVMs), 13-oleandrosyl-oleandrosyloxy ST906 (1) and aromatic TVM B (2), were isolated from the fermentation broth of Streptomyces avermitilis HU02-06. Their structures were established by extensive spectroscopic analysis, including 1D and 2D NMR and HRESIMS data. Bioassay test showed that these two new tenvermectins exhibited weak nematocidal activity against Bursaphelenchus xylophilus and moderate cytotoxic activity against tumor cell lines HepG2 and HCT116.

Assessing the In Vitro Individual and Combined Effect of Arthrobotrys oligospora and A. musiformis (Orbiliales) Liquid Culture Filtrates against Infective Larvae of the Sheep Blood-Feeding Nematode Haemonchus contortus (Trichostrongylidae).

Arthrobotrys species are nematophagous fungi that secrete extracellular nematocidal products (ECP). The individual and combined effects of ECP from Arthrobotrys oligospora (Ao) and A. musiformis (Am) growth in liquid media against Haemonchus contortus L3 (HcL3) were assessed. The isolation, morphological (MI) and molecular identification (Mol-I), assessment of nematocidal activity (NA) of fungal liquid culture filtrates (LCF) in two liquid media alone and in combination and the myco-compound profile identification (MCP) were performed. The MI suggested that the fungi corresponded to the species Ao and Am. This result was confirmed by PCR analysis followed by sequencing, alignment and a phylogenetic analysis. Likewise, the highest Hc mortalities were 91.4% with individual LCF of Am and 86.2% with those of Ao at the highest concentration (100 mg/mL) in Czapek-Dox Broth. The combination of both LCF resulted in a similarly high larval mortality with no statistical differences in relation to individual activity (p > 0.05). The MCP showed the presence of alkaloids in both fungi. Coumarins, sterols and saponins were found only in Ao. Both fungi produced ECP with a high NA that could be identified and assessed in future studies as potential natural anthelmintic compounds.

The nematode (Ascaris suum) intestine is a location of synergistic anthelmintic effects of Cry5B and levamisole.

A novel group of biocidal compounds are the Crystal 3D (Cry) and Cytolytic (Cyt) proteins produced by Bacillus thuringiensis (Bt). Some Bt Cry proteins have a selective nematocidal activity, with Cry5B being the most studied. Cry5B kills nematode parasites by binding selectively to membrane glycosphingolipids, then forming pores in the cell membranes of the intestine leading to damage. Cry5B selectively targets multiple species of nematodes from different clades and has no effect against mammalian hosts. Levamisole is a cholinergic anthelmintic that acts by selectively opening L-subtype nicotinic acetylcholine receptor ion-channels (L-AChRs) that have been found on muscles of nematodes. A synergistic nematocidal interaction between levamisole and Cry5B at the whole-worm level has been described previously, but the location, mechanism and time-course of this synergism is not known. In this study we follow the timeline of the effects of levamisole and Cry5B on the Ca2+ levels in enterocyte cells in the intestine of Ascaris suum using fluorescence imaging. The peak Ca2+ responses to levamisole were observed after approximately 10 minutes while the peak responses to activated Cry5B were observed after approximately 80 minutes. When levamisole and Cry5B were applied simultaneously, we observed that the responses to Cry5B were bigger and occurred sooner than when it was applied by itself. It is proposed that the synergism is due to the cytoplasmic Ca2+ overload that is induced by the combination of levamisole opening Ca2+ permeable L-subtype nAChRs and the Ca2+ permeable Cry5B toxin pores produced in the enterocyte plasma membranes. The effect of levamisole potentiates and speeds the actions of Cry5B that gives rise to bigger Ca2+ overloads that accelerates cell-death of the enterocytes.

Phytochemical Profile and GC-MS-Identified Bioactive Compounds in Pluchea ovalis (Pers.) DC. Leaves

Background: Pluchea ovalis is a significant medicinal plant that belongs to the Asteraceae family. It is also known as “Woolly Camphor-Weed” and has traditionally been used in Ayurveda, Siddha, and Folk medicine for treating numerous ailments, particularly Jaundice, Piles, Bronchial Asthma, inflammation, and Carcinoma. Purpose: Phytochemical Profile and GC-MS-Identified Bioactive Compounds in Pluchea ovalis Research Design: The phytochemical composition of P. ovalis leaves was screened using a Soxhlet apparatus after hot, continuous, and consecutive extraction. A variety of solvents were used for the qualitative assay. Different solvents were used in increasing polarity order to carry out the extraction operation. Total content of tannins, phenolic compounds, alkaloids (bromocresol green), and flavonoids (aluminum chloride) quantified (Folin-Ciocalteu). Additionally, quick and precise GC was used in conjunction with the Mass Hunter tool and mass spectrometry method to examine the absorbed components and determine the complete elements. Results: The qualitative phytochemical screening revealed that alkaloids, flavonoids, saponins, steroids & terpenoids, phenols, tannins, glycosides, phytosterols, coumarins, quinones resins, cardiac glycosides, leuco anthocyanins, anthraquinones and fixed oils were found in all the extracts, the quantification of alkaloids in methanol, showcasing a remarkable concentration of 502 mg/g equivalent, while chloroform exhibits a substantial alkaloid content of 310 mg/g, flavonoids, yielding the highest concentration in methanol at 520 mg/g and ethyl acetate at 440 mg/g. Phenols and tannins in methanol 390 mg/g and 320 mg/g . Gas chromatography-mass spectrometry (GC-MS) analysis of P. ovalis leaf methanol extract revealed 50 peaks, identifying bioactive compounds based on retention time, molecular formula, structure, weight, and concentration (peak area%). The results indicated that the single major component, dodecanoic acid, 1,2,3-propanetriyl ester (C39H74O6), had a peak area of 38.16%, a molecular weight of 638, and was reported to have hypercholesterolemic, anti-arthritic, nematocidal and hepatoprotective activity. 2-Ethoxyethylamine (C4H11NO), on the other hand, had the second-highest peak area, at 26.46%

Torenia sp. Extracts Contain Multiple Potent Antitumor Compounds with Nematocidal Activity, Triggering an Activated DNA Damage Checkpoint and Defective Meiotic Progression.

Previously, we analyzed 316 herbal extracts to evaluate their potential nematocidal properties in Caenorhabditis elegans. In this study, our attention was directed towards Torenia sp., resulting in reduced survival and heightened larval arrest/lethality, alongside a noticeable decrease in DAPI-stained bivalent structures and disrupted meiotic progression, thus disrupting developmental processes. Notably, Torenia sp. extracts activated a DNA damage checkpoint response via the ATM/ATR and CHK-1 pathways, hindering germline development. LC-MS analysis revealed 13 compounds in the Torenia sp. extracts, including flavonoids, terpenoids, tanshinones, an analog of resveratrol, iridoids, carotenoids, fatty acids, and alkaloids. Of these, 10 are known for their antitumor activity, suggesting the potential of Torenia species beyond traditional gardening, extending into pharmaceutical and therapeutic applications.

Transcriptome analysis highlights the influence of temperature on hydrolase and traps in nematode-trapping fungi.

Pine wilt disease caused by Bursaphelenchus xylophilus poses a serious threat to the economic and ecological value of forestry. Nematode trapping fungi trap and kill nematodes using specialized trapping devices, which are highly efficient and non-toxic to the environment, and are very promising for use as biological control agents. In this study, we isolated several nematode-trapping fungi from various regions and screened three for their high nematocidal efficiency. However, the effectiveness of these fungi as nematicides is notably influenced by temperature and exhibits different morphologies in response to temperature fluctuations, which are categorized as "NA," "thin," "dense," and "sparse." The trend of trap formation with temperature was consistent with the trend of nematocidal efficiency with temperature. Both of which initially increased and then decreased with increasing temperature. Among them, Arthrobotrys cladodes exhibited the highest level of nematocidal activity and trap formation among the tested species. Transcriptome data were collected from A. cladodes with various trap morphologies. Hydrolase activity was significantly enriched according to GO and KEGG enrichment analyses. Eight genes related to hydrolases were found to be consistent with the trend of trap morphology with temperature. Weighted gene co-expression analysis and the Cytoscape network revealed that these 8 genes are associated with either mitosis or autophagy. This suggests that they contribute to the formation of "dense" structures in nematode-trapping fungi. One of these genes is the serine protein hydrolase gene involved in autophagy. This study reveals a potentially critical role for hydrolases in trap formation and nematocidal efficiency. And presents a model where temperature affects trap formation and nematocidal efficiency by influencing the serine protease prb1 involved in the autophagy process.

1H-NMR Metabolomic Study of the Mushroom Pleurotus djamor for the Identification of Nematocidal Compounds.

Due to the increasing populations of anthelmintic-resistant gastrointestinal nematodes and as a consequence of the adverse effects of synthetic drugs, this study focuses on the search for secondary metabolites with nematocidal activity from the edible mushroom Pleurotus djamor using The proton nuclear magnetic resonance (1H-NMR) metabolomics. The highest activity was shown by the ethyl acetate fractions of mycelium (EC50 290.8 µg/mL) and basidiomes (EC50 282.7 µg/mL). Principal component analysis (PCA) and hierarchical data analysis (HCA) of the 1H-NMR metabolic profiles data showed that the ethanolic extracts, the ethyl acetate, butanol, and water fractions from mycelium have different metabolic profiles than those from basidiomes, while low polarity (hexane) fractions from both stages of fungal development show similar profiles. Orthogonal partial least squares discriminant analysis (OPLS-DA) allowed the identification of signals in the 1H-NMR metabolic profile associated with nematocidal activity. The signals yielded via OPLS-DA and bidimensional NMR analysis allowed the identification of uracil as a component in the ethyl acetate fraction from basidiomes, with an EC50 of 237.7 µg/mL. The results obtained showed that chemometric analyses of the 1H-NMR metabolic profiles represent a viable strategy for the identification of bioactive compounds from samples with complex chemical profiles.

Linking the protease activity to the nematicidal action of edible mushroom.

Biological control using edible mushrooms as natural enemies is a sustainable alternative for pest management. Despite the well-established literature on toxins and secondary metabolites produced by these fungi in the biochemical control of nematodes, the nematicidal activity of proteases from different Pleurotus species is yet to be investigated. Therefore, this study aimed to correlate protease to the nematicidal activity of different mushrooms, Pleurotus sp., P. ostreatus (SB), P. ostreatus (Pearl), and P. djamor. For such a purpose, we performed motility assays of Panagrellus sp. at different time intervals, 6, 12, and 24h for each of the mushrooms. In addition, the protease activity was measured using different pH (5, 7, and 9) and fermentation time intervals (45 and 75 days). Furthermore, we also evaluated the effect of this cell-free extract on Panagrellus sp. In response to these experiments, all edible mushrooms showed a reduction over 82% for the nematode-feeding activity (p < 0.01). The cell-free crude extract of each of the fungi studied showed nematocidal activity (p < 0.01). For the 45-day fermentation, P. djamor exhibited statistical significance (p < 0.01) compared with the others, reaching a reduction percentage of 73%. For the 75-day fermentation, Pleurotus sp. and P. ostreatus (Pearl) showed significant differences compared with the other fungi (p < 0.01), with reduction percentages of 64 and 62%, respectively. Herein, protease activity was associated with the nematicidal action of different Pleurotus species in controlling Panagrellus sp.

Improvement of agave bagasse hydrolysates processing under a biorefinery approach

SummaryThe economic viability of producing second-generation bioethanol from agave bagasse (AB) is influenced by the presence of phenolic compounds in the hydrolysates used during fermentation. These compounds substantially constrain the growth in yeasts that convert sugars into bioethanol, thus becoming a limitation for the process. In this study, it was proposed to select an effective adsorbent matrix to remove and recover phenolic compounds from AB hydrolysates. The related adsorption phenomena and processes were described and characterized. Four adsorbents were examined, including activated carbon (CA), as well as three polymeric matrices (MN-102, ADS-800EP, and SP825L). The adsorption parameters, such as maximum equilibrium adsorption capacity (qmax) and percent desorption, were determined through adsorption–desorption experiments in batch systems. Additionally, the impact of removing phenolic compounds on bioethanol yield was evaluated and the potential use of the recovered phenols as biopesticides against plant pathogens, such as fungi and nematodes, was explored. The results showed that activated carbon has a higher phenol adsorption capacity (qmax = 118.1 mg/g) but a lower desorption capacity (59.46 %), meanwhile, the MN-102 matrix displayed comparable adsorption characteristics and superior desorption capacity (95.81 %), rendering it the most appropriate for the process. Subsequently, the detoxification of the AB hydrolyzate, by phenolic compounds remotion, on bioethanol yield was assessed and resulted in a significant increase (3.5-fold). Finally, the fungicidal potential of the recovered phenolic compounds was evaluated on Fusarium oxysporum and Alternaria alternata, while the nematicidal activity was tested on Meloidogyne incognita. The phenolic compounds exhibited high antifungal activity against F. oxysporum (73.91 %) and moderate activity against A. alternata (40 %), in comparison to the positive control. Moreover, they showed very high nematicidal activity, causing 91.23 % mortality in M. incognita. These findings allow to conclude that incorporating the adsorption stage not only enhances bioethanol yields but also enables the efficient recovery of potentially valuable molecules.

The activity of leaf extracts, fractions, and isolated compounds from Ptaeroxylon obliquum against nine phytopathogenic fungi and the nematode Meloidogyne incognita

Phytopathogenic fungi and nematodes cause great losses in economically important crops and food production especially in developing countries. To minimize the use of fungicides and nematicides, researchers have concentrated on the use of natural products for crop disease prevention or control. The aim of the study was to investigate the antifungal activity of Ptaeroxylon obliquum leaf extracts, fractions, and isolated compounds (obliquumol and a mixture of lupeol and β-amyrin) and nematocidal activity of fractions (hexane, chloroform and 30% water in methanol and the isolated compounds) on Meloidogyne incognita. Nine phytopathogenic fungi (Aspergillus niger, A. parasiticus, Colletotrichum gloeosporioides, Fusarium oxysporum, Penicillium digitatum, P. expansum, P. italicum, P. janthinellum, and Rhizoctonia solani) were used for testing and nematocidal activity was determined on motility of plant parasitic nematode Meloidogyne incognita race 2 juveniles. Serial microdilution test was utilized to determine the minimum inhibitory concentration (MIC) of each sample against the fungus. Motility tests was done on the second-stage juveniles (J2s) of M. incognita. The most susceptible phytopathogenic fungal species to the acetone crude leaf extracts were A. niger, C. gloeosporioides and P. digitatum with MIC of 80 μg/ml which is considered pharmacological significant. Rhizoctonia solani was the most susceptible fungus against obliquumol and, lupeol and β-amyrin mixture with MIC values of 8 μg/ml and 16 μg/ml respectively. Lupeol & β-amyrin mixture had good activity on juvenile motility at high concentrations used which was significantly high (p ≤ 0.05) after 24 h, further incubation resulted in temporary paralysis at lower concentrations. Fractions and obliquumol showed good activity after 48 h, stable paralysis was observed up to 72 h. The extracts and isolated compounds may be useful as fungicides if the in vitro results can be confirmed under field conditions at levels not toxic to beneficial soil organisms.