Control Agents Research Articles

Assessing the feasibility of pre-emptive biological control against the emerald ash borer, Agrilus planipennis, an imminent biosecurity threat to Europe

As the globalisation of trade increases, so does the spread of arthropod pests, leading to a growing focus on biosecurity preparedness. One approach to this is pre-emptive biological control, involving the importation of classical biological control (CBC) agents for risk assessments and acquiring approval for their release prior to the expected arrival of their target pests. This aims to mitigate the economic and/or environmental consequences of a delayed biological control response to pest invasions. Guidelines to assess the feasibility of pre-emptive biological control for high priority pests were recently developed. Emerald ash borer (EAB), Agrilus planipennis, is an invasive woodboring pest of ash (Fraxinus spp.) in North America, European Russia and Ukraine, and is spreading westward into Europe, threatening the future of European ash (Fraxinus excelsior). We applied the aforementioned guidelines to assess the feasibility of pre-emptive biological control in Europe using four EAB parasitoids, already released in North America for CBC. Three of the parasitoids; Oobius agrili, Spathius galinae, and Tetrastichus planipennisi, were found suitable for pre-emptive biological control. The fourth parasitoid, Spathius agrili, was found to have limited establishment in new environmental conditions, and was therefore deemed less suitable for pre-emptive biological control of EAB in Europe. This assessment can inform scientists and regulators in Europe on the most promising EAB parasitoids that should be considered for pre-emptive applications for importation and risk assessment to acquire pre-approval for immediate release should the target pest subsequently be discovered. In turn, this study contributes to the development of biosecurity preparedness against EAB’s imminent spread throughout Europe.

HDAC inhibitor SAHA enhances antitumor immunity via the HDAC1/JAK1/FGL1 axis in lung adenocarcinoma

BackgroundHistone deacetylase (HDAC), a kind of protease that regulates gene expression by modifying protein acetylation levels, is usually aberrantly activated in tumors. The approved pan-HDAC inhibitors (HDACi) have exhibited clinical...

Natural volatiles preventing mosquito biting: an integrated screening platform for accelerated discovery of ORco antagonists

Insect olfactory receptors are heteromeric ligand-gated cation channels composed of an obligatory receptor subunit, ORco, and one of many variable subunits, ORx, in as yet undefined molar ratios. When expressed alone ex vivo, ORco forms homotetrameric channels gated by ORco-specific ligands acting as channel agonists. Using an insect cell-based system as a functional platform for expressing mosquito odorant receptors ex vivo, we identified small molecules of natural origin acting as specific ORco channel antagonists, orthosteric or allosteric relative to a postulated ORco agonist binding site, which cause severe inhibition of olfactory function in mosquitoes. In the present communication, we have compiled common structural features of such orthosteric antagonists and developed a ligand-based pharmacophore whose properties are deemed necessary for binding to the agonist binding site and causing inhibition of ORco's biological function. In silico screening of an available collection of natural volatile compounds with the pharmacophore resulted in identification of several ORco antagonist hits. Cell-based functional screening of the same compound collection resulted in the identification of several compounds acting as orthosteric and allosteric antagonists of ORco channel function ex vivo and inducing anosmic behaviors to Aedes albopictus mosquitoes in vivo. Comparison of the in silico screening results with those of the functional assays revealed that the pharmacophore predicted correctly 7 out of the 8 confirmed orthosteric antagonists and none of the allosteric ones. Because the pharmacophore screen produced additional hits that did not cause inhibition of the ORco channel function, we also generated a Support Vector Machine (SVM) model based on two descriptors of all pharmacophore hits. Training of the SVM on the ex vivo validated compound collection resulted in the selection of the confirmed orthosteric antagonists with a very low cross-validation out-of-sample misclassification rate. Employment of the combined pharmacophore-SVM platform for in silico screening of a larger collection of olfaction-relevant volatiles produced several new hits. Functional validation of randomly selected hits and rejected compounds from this screen confirmed the power of this virtual screening platform as a convenient tool for accelerating the pace of discovery of novel vector control agents. To the best of our knowledge, this study is the first one that combines a pharmacophore with a SVM model for identification of AgamORco antagonists and specifically orthosteric ones.

Impact of biopolymer-based Trichoderma harzianum seed coating on disease incidence and yield in oilseed crops

The use of microbe-based biological control for crop pests is recognized as an environmentally safe substitute for conventional chemical pesticides. However, the practical application of microbial inoculants in large-scale agriculture is underexplored, impeding their widespread commercial adoption. This study addresses the scarcity of research on effective delivery methods for microbial inoculants, particularly through seed coating, which has the potential to be a cost- and time-efficient strategy in crop management. In this research, the Trichoderma harzianum strain Th4d, a biological control agent (BCA), was incorporated into specially formulated biopolymeric compositions based on chitosan and cellulose. The efficacy of this seed coating approach was tested against various soil- and seed-borne pathogens in oilseed crops, including soybean, groundnut, and safflower. Results indicate that safflower treated with the biopolymer chitosan-based T. harzianum Th4d 1 % liquid formulation blend exhibited a higher seed yield of 793 kg/ha, seed germination of 84.7 %, and a significant reduction in wilt and root rot by 64.7 %. In groundnut crops, the seed coating led to a seed germination rate of 88.6 %, a 72 % reduction in root rot incidence, and a seed yield of 3040 kg/ha. Similarly, soybean crops treated with the biopolymer chitosan and T. harzianum Th4d displayed 83.4 % seed germination, a 70.9 % reduction in root rot, and a seed yield of 1239 kg/ha. Further on-farm evaluations demonstrated promising results, with the biopolymer chitosan-based T. harzianum Th4d 1 % liquid formulation blend seed treatment showing a high incremental cost-benefit ratio in safflower (1:4.5), soybean (1:2.5), and groundnut crops (1:3.3). This study underscores the potential of microbe-based seed coating as a sustainable and economically viable strategy for pest management in oilseed crops."

The influence of ball milling conditions on the powder characteristics and sintering densification of Mo[sbnd]Cu alloy

Mechanical alloying was utilized to produce Mo-30Cu(wt%) composite powder. The effects of milling conditions on the powder characteristics and sintering densification were investigated. The morphological evolution during the mechanical alloying process can be categorized into four stages: 1-individual Mo and Cu particles, 2-coexistence of Mo particles and blocky MoCu composite particles, 3-coarse irregular composite particles, and 4-refined near-spherical composite particles or lamellar MoCu composite particles, depending on whether process control agent (PCA) is added. The mechanical alloying degree of the MoCu composite powder was deepened gradually from stage 1 to 4, which is influenced by the ball milling parameters. As the milling speed and milling time increase, the lattice strain and the alloying degree of the MoCu composite powders increase while the grain size of molybdenum particles decreases, which is conducive to accelerating the sintering density. Among these ball milling parameters, an elevated milling speed notably accelerates the mechanical alloying process and the sintering density. Under the milling speed of 600 r/min, ball to powder ratio (BPR) of 10:1, and milling time of 4 h, the grain size, lattice strain, and average particle diameter of the composite powder were measured to be 48.4 nm, 0.247 %, and 21.04 μm, respectively, with the particle morphology being nearly spherical. The sintered density of the MoCu composite reached 98.1 %, larger than the other composites.

Functional structure of the natural enemy community of the fall armyworm, Spodoptera frugiperda in the Americas

Ecosystem functions such as biological pest control are mediated by the richness and abundance of service providers i.e., biological control agents (BCAs), relative contributions of individual taxa and community structure. This is especially relevant in the native range of agricultural herbivores, where a speciose community of co-evolved BCAs can prevent them from attaining pest status. Here, we use a powerful graphical approach to assess the functional structure of BCA communities of the fall armyworm (FAW) Spodoptera frugiperda (Lepidoptera: Noctuidae) on maize in the Neotropics. Drawing upon a curated database of all-time field and laboratory studies, we graphed patterns in the functional contribution, abundance and niche breadth for a respective 69, 53 and 3 taxa of resident parasitoids, predators and pathogens. Regardless of varying taxon coverage and rigor of the underlying studies, functional structure follows a saturating relationship in which the first three taxa account for 90–98% of aggregate biological control function. Abundance-functionality matrices prove critically incomplete, as more than 80% of invertebrate taxa miss empirically derived efficiency metrics while associated FAW infestation data are scarce. Despite its methodological shortfalls and data gaps, our work pinpoints Chelonus insularis, Cryptus albitarsis, several taxa of egg parasitoids, Doru spp. and Orius spp. as taxa with outsized functionality and conservation potential. This is also exemplified by the highly variable aggregate function across studies, with dispersion indices of 1.52 and 2.14 for invertebrate BCAs. Our work underlines the critical importance of functional ecology research, networked trials and standardized methodologies in advancing conservation biological control globally

Assessing the Efficacy of Melia azedarach Leaf Extracts as a Mosquito Control Agent Against Aedes aegypti and Culex quinquefasciatus

Assessing the Efficacy of Melia azedarach Leaf Extracts as a Mosquito Control Agent Against Aedes aegypti and Culex quinquefasciatus

Evaluating Treatments for the Protection of Grapevine Pruning Wounds from Natural Infection by Trunk Disease Fungi.

Infection of grapevines by fungal pathogens causing grapevine trunk diseases (GTDs) primarily arises from annual pruning wounds made during the dormant season. While various studies have showcased the efficacy of products in shielding pruning wounds against GTD infections, most of these investigations hinge on artificial pathogen inoculations, which may not faithfully mirror real field conditions. This study aimed to evaluate and compare the efficacy of various liquid formulation fungicides (pyraclostrobin + boscalid) and paste treatments, as well as biological control agents (BCA: Trichoderma atroviride SC1, T. atroviride I-1237, and T. asperellum ICC012 + T. gamsii ICC080), for their potential to prevent natural infection of grapevine pruning wounds by trunk disease fungi in two field trials located in Samaniego (Northern Spain) and Madiran (Southern France) over three growing seasons. Wound treatments were applied immediately after pruning in February. One year after pruning, canes were harvested from vines and brought to the laboratory for assessment of Trichoderma spp. and fungal trunk pathogens. More than 1,200 fungal isolates associated with five GTDs (esca, Botryosphaeria, Diaporthe and Eutypa diebacks, and Cytospora canker) were collected from the two vineyards each growing season. Our findings reveal that none of the products under investigation exhibited complete effectiveness against all the GTDs. The efficacy of these products was particularly influenced by the specific year of study. A notable exception was observed with the biocontrol agent T. atroviride I-1237, which consistently demonstrated effectiveness against Botryosphaeria dieback infections throughout each year of the study, irrespective of the location. The remaining products exhibited efficacy in specific years or locations against particular diseases, with the physical barrier (paste) showing the least overall effectiveness. The recovery rates of Trichoderma spp. in treated plants were highly variable, ranging from 17 to 100%, with both strains of T. atroviride yielding the highest isolation rates. This study underscores the importance of customizing treatments for specific diseases, taking into account the influence of environmental factors for BCA applications.

The synergistic potential of polyethylene glycol 400 for the control of Hyphantria cunea larvae by Beauveria bassiana

The efficacy of entomopathogenic fungi as pest control agents is constrained by both their physiological state and external environmental factors. This study identified synergists capable of enhancing the insecticidal activity of Beauveria bassiana (Bb) and investigated the underlying synergistic mechanisms. Our results found that among 6 potential synergists, polyethylene glycol 400 (PEG) and trehalose significantly improved Bb's lethality against Hyphantria cunea larvae, with PEG demonstrating the most pronounced effect. PEG treatment markedly increased Bb spore adhesion and germination rates, while spore hydrophobicity and growth rates remained unaffected. Moreover, PEG-treated spores exhibited higher thermal tolerance compared to untreated ones. In the Bb + PEG treatment group, the hemocyte count, encapsulation and melanization activities, and the expression of related regulatory genes were significantly lower than those in the Bb treatment group. Additionally, pathogen recognition, signal transduction, and humoral immunity effector genes expression were markedly suppressed in the Bb + PEG group. A significant reduction in the content of total amino acids, free fatty acids, glucose, and trehalose, alongside decreased expression of key regulatory genes in the tricarboxylic acid cycle and glycolysis pathways, was observed in the Bb + PEG treatment group. Furthermore, PEG enhanced Bb-induced apoptosis in H. cunea larvae, as evidenced by the upregulation of apoptosis-related genes. Notably, PEG alone did not significantly impact the innate immunity, energy metabolism, or apoptosis in H. cunea larvae. Overall, PEG exhibits considerable potential in amplifying Bb's insecticidal activity by directly optimizing spore performance and indirectly modulating the larvae's innate immunity, energy metabolism, and apoptosis.

Evaluation of Biocides Susceptibility and Expression of Qace-Δ1 And Suge1 Genes of Pseudomonas Aeruginosa in Exposure to Biocides and Meropenem

Pseudomonas aeruginosa is a species of medical significance that plays a role in nosocomial infections, particularly those resulting from burns and wounds. Bacterial antibiotic resistance may have developed as a result of the abuse of biocides in hospitals. This study aimed to determine the minimum inhibitory concentrations (MICs) of carbapenem-resistant P. aeruginosa isolates in relation to ethylenediaminetetraacetic acid (EDTA), chlorohexidine (CHX), and resazurin dye using a microtiter plate assay. Additionally, it evaluated the expression of the efflux pump genes (qacE-Δ1 and sugE1) at sub-inhibitory concentrations of the biocides using RT-qPCR (delta delta Ct method) to improve their efflux pump system. The MICs of 24 P. aeruginosa isolates (14 isolates were resist to carbapenems and 10 isolates sensitive to carbapenems) against Chloroxylenol (Dettol) revealed that the range of MICs were (0. 125-2%). The results of MICs of Chlorohexidine (CHX) revealed that the range of inhibitory activity was (0.8-102.4 µg/ml), also the findings of MICs of EDTA demonstrated that the range of inhibitory activity was (125-2000 µg/ml). The genes involved in efflux pump (qacE -Δ1 and sugE1) were found to be significantly up-regulated in the local isolates, according to our findings.. The four isolates' sugE1 gene expression folds ranged from 1.81 to 5.39; this result was more than the fold of the control (the fold change is 1), with the meropenem isolate having the highest fold value (5.39) and sub-MIC value (8 µg/ml). Furthermore, the four isolates' qacE-Δ1 gene expression folds ranged from 2.11 to 5.01, which was higher than the fold of the control, where the highest fold value was recorded for the EDTA (5.01) with the sub-MIC value (125-500 µg/ml). Also, a high value of upregulation of the gene qacE –Δ1, during the treatment with dettol with sub-MIC (0.25-0.5%), and the fold change was 4.19. In conclusion, the present findings indicated to the significant relationship between the treatments with meropenem and the high values of gene expression of the gene sugE1 in comparison with the control and other agents, Furthermore, compared to the antibiotic and control, there was a strong correlation found between the high fold changes of the gene qacE -Δ1 with the presence of dettol and EDTA.

The influence of genetic variation on pre‐oviposition processes for host‐parasitoid co‐evolution

Abstract Despite the importance of parasitoid wasps as biological control agents and the vast literature available on different aspects of their natural history and ecology, it is only recently that an interest in integrating genetics into aphid‐parasitoid studies has emerged. Some studies have been completed on the effect of genetic variation on aphid parasitism outcomes, especially after the description of aphid physiological resistance to parasitoids and its role in their co‐evolution. The interaction between aphids and parasitoids goes beyond the physiological conflict between the parasitoid egg and the aphid internal defences. A series of aphid and parasitoid attributes, that can be influenced by biotic and abiotic factors, precedes that last step in the oviposition process. The understanding of how genetic variation can play a crucial role in influencing the pre‐egg‐laying stages of the aphid‐parasitoid interaction remains relatively unexplored. Here, we review currently available information on this topic. We contextualise the aphid‐parasitoid co‐evolution process exemplified by the post‐oviposition approach. Knowledge gaps are also discussed and the significance of fulfilling them is addressed. An ecology‐evolutionary perspective on aphid‐parasitoid research is advocated, by incorporating genetic variation into the study of aphid‐parasitoid co‐evolution. This will increase the understanding of the adaptation and evolution of both organism's characteristics in response to each other and abiotic pressures, and also the implications for pest management.

Novel heterocyclic amide derivatives containing a diphenylmethyl moiety: systematic optimizations, synthesis, antifungal activity and action mechanism.

The development of fungicides with low cross resistance, high efficacy and low resistance plays a central role in protecting crops, reducing yield losses, improving quality and maintaining global food security. Based on this important role, after a systematic optimization strategy, novel heterocyclic amide derivatives bearing diphenylmethyl fragment were screened, synthesized and verified with the spectrographic and x-ray diffraction analysis. In this study, the aforementioned optimization obtained compound B19 that was measured for antifungal activity against Rhizoctonia solani (median effective concentration, EC50 = 1.11 μg mL-1). Meanwhile, the anti-R. solani protective effect (79.34%) of compound B19 was evaluated in vivo at 100 μg mL-1, which is comparable to that of the control agent fluxapyroxad (80.67%). Thence, morphological observations revealed that compound B19 induced mycelium disruption and shrinking, mitochondrial number reduction and apoptosis acceleration, consistent with the results of the mitochondrial membrane potential and cell membrane permeability. Further investigations found that the potential target enzyme of compound B19 was SDH, which exerted fluorescence quenching dynamic curves similar to that of the commercialized SDHI fluxapyroxad. Additionally, research by molecular docking and MD simulations demonstrated that compound B19 had a similar binding mode acting on the surrounding residues in the SDH active pocket to that offluxapyroxad. The above results demonstrated that heterocyclic amide derivatives containing a diphenylmethyl moiety are promising scaffolds for targeting SDH of fungi and provide valuable antifungal leads with the potential to develop new SDH inhibitors. © 2024 Society of Chemical Industry.

Development of a Multiplex Polymerase Chain Reaction Assay for Detecting Five Previously Unreported Papaya Viruses for Quarantine Purposes in Korea

There are concerns about the introduction and spread of plant pests and pathogens with globalization and climate change. As commercial control agents have not been developed for plant viruses, it is important to prevent virus spread. In this study, we developed a multiplex polymerase chain reaction (PCR) detection method to rapidly diagnose and control three DNA (papaya golden mosaic virus, Lindernia anagallis yellow vein virus, and melon chlorotic leaf curl virus) and two RNA (papaya leaf distortion mosaic virus and lettuce chlorosis virus) viruses that infect papaya. Specific primer sets were designed for the virus coat protein. Performing PCR, clear bands were observed with no non-specific reaction. Our multiplex PCR method can simultaneously detect small amounts of DNA/RNA to diagnose five viruses infecting papaya and prevent the spread of the virus.

Characterization of Twelve Erwinia amylovora Bacteriophages

Erwinia amylovora bacteriophages are of interest as fire blight control agents. This paper presents data on the biology and molecular genetic properties of 12 E. amylovora tailed bacteriophages. Genome sequences of seven of them were determined and the phages were identified as the representatives of Caudoviricetes; Vequintavirinae, Ounavirinae and Autographiviridae families. The bacteriophages studied were active against E. amylovora, Pantoea agglomerans and Pantoea ananatis strains. The myovirus Hena1 had the narrowest host range lysing 12% of the bacterial cultures tested, the remaining myoviruses—had broader host ranges (56%) for this collection. The phages showed different reactions to the presence of a chelating agent in the cultivation medium. A significant proportion of phage-resistant E. amylovora cells were found both in infected liquid cultures and in the experiments on the plates with the phage agar (more than 20% in case of exposure to podoviruses), which correlates with the data of limited number of previous investigations of the phenomenon for E. amylovora interactions with phages. High prevalence of resistant cells in the host cultures suggest that they are formed not due to spontaneous mutations but result from another phenotypic or genetic dissociation mechanism(s) that remains to be identified.

Predation Efficiency and Biological Control Potential of Micromus angulatus Against Aphis craccivora

Micromus angulatus (Neuroptera: Hemerobiidae) is a widely distributed and highly effective predator that shows promise as a biological control agent against agricultural pests, particularly Aphis craccivora, the cowpea aphid, which threatens leguminous crops globally. This study aimed to evaluate the predation behaviour, search efficiency, and intraspecific interference of M. angulatus at different developmental stages, including first- to third-instar larvae and adults, in controlling adult A. craccivora populations. The results demonstrated that all developmental stages of M. angulatus exhibited predatory behaviour towards adult aphids, with the functional response fitting the Holling Type II model. The instantaneous attack rates for first-, second-, and third-instar larvae and adults were 1.0017, 1.0448, 0.9581, and 0.9508, respectively; the handling times were 0.0158, 0.0051, 0.0016, and 0.0011 days, respectively; and the theoretical maximum daily predation rates were 63.2911, 196.0784, 625, and 909.0909 aphids, respectively. The pest control efficacies were 63.3989, 204.8672, 598.8311, and 864.3192, respectively. The search efficiency at each developmental stage was negatively correlated with aphid density, which decreased as the prey density increased, with second-instar larvae showing the greatest decrease and adults the least. When the aphid density was fixed, the daily predation rate of individual M. angulatus decreased with increasing conspecific density, indicating that predation was affected by its own density, with the interference effect equation being E = 0.6194P−0.87. These findings indicate that M. angulatus, especially in the third-instar larval and adult stages, has considerable potential as a biological control agent for managing A. craccivora populations in agricultural settings. This study contributes valuable insights for developing sustainable agricultural practices by decreasing reliance on chemical pesticides.

Side effects of semi-synthetic insecticide spinetoram on the whitefly parasitoid Encarsia formosa.

Insecticide risk assessment for biological control agents is essential for implementing integrated pest management (IPM) programs. Spinetoram is a naturally derived insecticide used to control a variety of agricultural sap-sucking insect pests, and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) plays a key role in the biocontrol of greenhouse whiteflies. Despite its presumed safe ecotoxicological profile, the side effects of spinetoram on E. formosa are partially unknown, especially at sublethal doses. In the laboratory, we estimated the lethal concentrations (LC) of spinetoram on E. formosa by topical exposure of pupae and 48 h residual contact exposure of emerged adults. Afterwards, we assessed the impact of spinetoram LCs on the life history traits (juvenile development, adult longevity, parasitism, adult emergence) and population growth parameter (the instantaneous rate of increase, ri) of the parasitoid. Probit analysis allowed the estimation of LC10 = 0.10 mg/L, LC50 = 0.56 mg/L, and LC90 = 3.28 mg/L. Spinetoram at LC10 had no impact on the observed parameters of E. formosa. Conversely, spinetoram at LC50 and LC90 significantly reduced adult longevity by 19.2% and 40.6%, total parasitism by 33.4% and 38.7%, and total adult emergence by 29.6% and 39.1%, respectively. Also, the ri of E. formosa was significantly affected by spinetoram LC50 and LC90 with a reduction of 8.17 and 29.83%, respectively. Our results suggested that spinetoram significantly threatens the effectiveness of E. formosa when applied at the field recommended rate. However, further validation of spinetoram under greenhouse conditions is required for a comprehensive risk assessment for E. formosa in IPM programs. © 2024 Society of Chemical Industry.

Development and Performance Evaluation of a New Conformance Control Agent Gel.

How to effectively plug the multi-scale fractured water channeling has always been the key to achieving efficient water flooding of fractured low-permeability oil reservoirs. In this paper, a new type of supramolecular-polymer composite gel is developed, which is suitable for plugging multi-scale fractured water channeling. The supramolecular-polymer composite gel is composed of a polymer (such as polyacrylamide), cross-linking agent (such as polyethyleneimine), supramolecular gel factor (such as cyclodextrin) and polarity regulator (such as ethyl alcohol). The mass fraction of polyacrylamide, polyethyleneimine, cyclodextrin and ethyl alcohol are 0.15%, 0.2%, 1% and 0.2%, respectively. At the initial state, the viscosity of the composite gelant system is less than 20 mPa·s. It has good injection performance in micro-scale fractures and can enter the deep part of a fractured reservoir. At 40 °C, the composite gelant system can form a gel with a double network structure after gelation. One of the networks is formed by the covalent interaction between polyacrylamide and polyethyleneimine, the other network is formed by the self-assembly of cyclodextrins under the action of the ethyl alcohol. The comprehensive performance of the composite gel is greatly improved. The strength of the composite gel is >5 × 104 mPa·s, and it has good plugging strength in large-scale fractures. The composite gel can be used as a conformance control agent for fractured low-permeability oilfields.

Are1-mediated nitrogen metabolism is associated with iron regulation in the mycoparasite Trichoderma atroviride

Trichoderma atroviride is a mycoparasitic fungus with antagonistic activity against fungal pathogens and is used as a pathogen control agent alternative to synthetic fungicides. Sensing nutrient availability in the environment and adjusting metabolism for optimal growth, development and reproduction is essential for adaptability and is relevant to its mycoparasitic activity. During mycoparasitism, secondary metabolites are produced to weaken the fungal prey and support the attack. Are1-like proteins act as major GATA-type transcription factors in the activation of genes subject to nitrogen catabolite repression. Since the quality and quantity of nitrogen has been proven particularly relevant in remodeling the biosynthesis of secondary metabolites in fungi, we decided to functionally characterize Are1, the ortholog of Aspergillus nidulans AreA, in T. atroviride. We show that the growth of the T. atroviride ∆are1 mutant is impaired in comparison to the wild type on several nitrogen sources. Deletion of are1 enhanced sensitivity to oxidative and cell-wall stressors and altered the mycoparasitic activity. We were able to identify for the first time a link between Are1 and iron homeostasis via a regulatory mechanism that does not appear to be strictly linked to the nitrogen source, but rather to an independent role of the transcription factor.

Antibiotic-resistant mutants of lactic acid bacteria: potential food control agents

Background: One of the most pressing challenges facing global agriculture today is the restoration of degraded farmland. Organic fertilisers are increasingly being used as a safer alternative to synthetic forms. The most promising form of environmentally friendly fertiliser is a bioconsortium based on different groups of microorganisms. Lactic acid bacteria (LAB) with high antifungal activity, isolated from Armenian dairy products, can form part of such a bioconsortium and protect plants from phytopathogens. In addition, LAB can be used as a preservative in the food industry due to its GRAS (generally recognised as safe) status. Objective: To obtain antibiotic-resistant pleiotropic lactic acid bacterial mutants with higher antifungal activity and broad-spectrum activity compared to natural strains. Methods: The objects of the study were LAB, whose antifungal activity was studied against phytopathogenic fungi of the genera Penicillium, Aspergillus, Alternaria and Fusarium, which cause crop/food spoilage. To increase antifungal activity, spontaneous pleiotropic mutants resistant to the streptomycin, kanamycin or rifampicin were obtained on the basis of original strains. Results: Among all the LAB tested, Lactobacillus bovis MDC 1061, L. paracasei MDC 10898 and L. buchneri BKM 1599 were selected for their antifungal activity. Based on the latter, 78 antibiotic-resistant mutants with different levels of antifungal activity were obtained. L. bovis MDC 1061 STR-25 and L. buchneri BKM 1599 RIF-7 mutants with up to 98% and 95% inhibition of fungal growth, respectively, were selected as potential food control agents. Conclusion: Antibiotic-resistant mutants L. bovis MDC 1061 STR-25 and L. buchneri BKM 1599 RIF-7 with high antifungal ability and a wide range of its effects were obtained. For the first time, the phenomenon of pleiotropic effect has been used in LAB to improve antifungal activity. After extensive study, these mutants can be used as promising components for creating an effective bioconsortium, as well as a preservative in food production, especially in the case of plant-based functional foods to protect against contamination by fungi. Keywords: lactic acid bacteria, pleiotropic mutants, antifungal activity

Morphophysiological and Histopathological Effects of Ammonium Sulfate Fertilizer on Aporrectodea trapezoides (Dugès, 1828) Earthworm.

The present study used the adult earthworm Aporrectodea trapezoides as a bioindicator species to look into the possible dangers of ammonium sulfate (AS) fertilizer. Two complementary toxicity tests were conducted to determine the LC50values, growth rate inhibition, morphological alterations, and histopathological texture of worms. The lethality test included four increasing concentrations of AS fertilizer (ranging from 2500 to 7500 mg/kg of dry soil weight (d.w.)), while sub-lethal concentrations were based on 10%, 30%, 40%, and 50% of the 14-day median lethal concentration (LC50), with a control group included for both tests. The LC(50) values for AS fertilizer were significantly higher at 7 days (4831.13 mg/kg d.w.) than at 14 days (2698.67 mg/kg d.w.) of exposure. Notably, earthworms exhibited significant growth rate inhibition under exposure to various concentrations and time durations (14/28 exposure days). Morphological alterations such as clitellar swelling, bloody lesions, whole body coiling and constriction, body strangulation, and fragmentation were accentuated steadily, with higher concentrations. Histopathological manifestations included severe injuries to the circular and longitudinal muscular layers, vacuolation, muscle layer atrophy, degradation of the chloragogenous tissue in the intestine, collapsed digestive epithelium of the pharynx with weak reserve inclusion, and fibrosis of blood vessels. These effects were primarily influenced by increasing concentrations of fertilizer and time exposure. The study highlights the strong relationship between concentration and exposure time responses and underscores the potential of A. trapezoides earthworms as valuable biological control agents against acidic ammonium sulfate fertilizer. Importantly, this research contributes to the use of such biomarkers in evaluating soil toxicity and the biological control of environmental risk assessment associated with chemical fertilizers.