Search Results (27)

The increasing resistance of agricultural pests to conventional pesticides necessitates the development of alternative biological control strategies. This study evaluated the acaricidal potential of two Photorhabdus luminescens strains (0805-P2R and the newly isolated 2103-RUVI) against the spider mite Tetranychus truncatus. Culture conditions were optimized using a Taguchi L9(3⁴) design to maximize growth, protease activity, and acaricidal efficacy. The optimized medium for strain 2103-RUVI achieved 90% mortality against T. truncatus at 72 h, compared to 83% for strain 0805-P2R under equivalent conditions. Genomic analysis identified putative phosphoporin PhoE genes exclusively in 2103-RUVI, which may contribute to its enhanced virulence, although this association remains correlative and requires functional validation. Histopathological observations confirmed severe tissue disruption in treated mites. Comparative analysis demonstrated complex, strain-specific relationships among bacterial growth, enzyme activity, and acaricidal effects. These results highlight the potential of the P. luminescens strain 2103-RUVI as an effective biocontrol agent, providing insights for its application in sustainable integrated pest management programs. Full article

Air–liquid interface (ALI) cultures offer a physiologically relevant in vitro model of the airway epithelium (AE), capable of recapitulating key structural and functional features observed in vivo. In this study, we established and validated a murine ALI culture system comprising pseudostratified epithelia with functional tight junctions, ciliated cells and goblet cells. To assess their innate immune functions, we designed and 3D-printed an autoclavable aerosol deposition chamber, which allowed us to expose differentiated AE cultures to house dust mite (HDM) allergen. Upon HDM exposure, AE cells mounted a time-dependent innate immune response characterized by the secretion of complement component C3, the generation of its active cleavage products C3a and increased expression of C3aR and C5aR1. This was associated with increased intracellular TSLP and IL-25 production and TSLP release in AE cells. Progressive loss of tight junction integrity and reduced transepithelial electrical resistance (TEER) demonstrated epithelial susceptibility to allergen protease-induced cell damage. Together, we established a murine ALI system preserving airway epithelial architecture and a nebulization system to study innate immune activation of AE cells in response to HDM mimicking the initial phase of allergen sensitization. More generally, we described a powerful and accessible platform for studying epithelial-driven mechanisms in murine airway immune responses. Full article

As the relationship between the gut microbiome and allergies becomes better understood, targeted strategies to prevent and treat allergies through gut microbiome modulation are being increasingly developed. In the study presented herein, we screened various probiotics for their ability to inhibit mast cell degranulation and identified Lactiplatibacillus plantarum HD02 and MD159 as effective candidates. The two strains significantly attenuated vascular permeability induced by mast cell degranulation in a passive cutaneous anaphylaxis (PCA) model and, in the MC903-induced murine atopic dermatitis (AD) model, demonstrated comparable preventive effects against allergies, reducing blood levels of MCPT-1 (mast cell protease-1) and total IgE. In the house dust mite (HDM)-induced murine AD model, both L. plantarum HD02 and MD159 showed therapeutic effects, with L. plantarum HD02 demonstrating superior efficacy. Nevertheless, L. plantarum MD159 better suppressed transepidermal water loss (TEWL). Furthermore, L. plantarum HD02 and MD159 significantly increased the number of splenic Foxp3⁺ regulatory T cells, with L. plantarum MD159 having a more pronounced effect. However, only L. plantarum HD02 achieved a reduction in immune cells in the draining lymph nodes. Our findings highlight L. plantarum HD02 and MD159 as promising candidates for the prevention and treatment of allergies, demonstrating significant efficacy in suppressing mast cell degranulation, reducing the number of allergy biomarkers, and modulating immune responses in experimental models of AD. Their distinct mechanisms of action suggest potential complementary roles in addressing allergic diseases, underscoring their therapeutic promise in clinical applications. Full article

Papain-like cysteine proteases are widespread and can be detected in all domains of life. They share structural and enzymatic properties with the group’s namesake member, papain. They show a broad range of protein substrates and are involved in several biological processes. These proteases are widely exploited for food, pharmaceutical, chemical and cosmetic biotechnological applications. However, some of them are known to cause allergic reactions. In this context, the objective of this review is to report an overview of some general properties of papain-like cysteine proteases and to highlight their contributions to allergy reactions observed in humans. For instance, the literature shows that their proteolytic activity can cause an increase in tissue permeability, which favours the crossing of allergens through the skin, intestinal and respiratory barriers. The observation that allergy to PLCPs is mostly detected for inhaled proteins is in line with the reports describing mite homologs, such as Der p 1 and Der f 1, as major allergens showing a frequent correlation between sensitisation and clinical allergic reactions. In contrast, the plant food homologs are often digested in the gastrointestinal tract. Therefore, they only rarely can cause allergic reactions in humans. Accordingly, they are reported mainly as a cause of occupational diseases. Full article

Chronic rhinosinusitis (CRS) is an inflammation of the nasal and paranasal sinus mucosa, and eosinophilic CRS (eCRS) is a subtype characterized by significant eosinophil infiltration and immune response by T-helper-2 cells. The pathogenesis of eCRS is heterogeneous and involves various environmental and host factors. Proteases from external sources, such as mites, fungi, and bacteria, have been implicated in inducing type 2 inflammatory reactions. The balance between these proteases and endogenous protease inhibitors (EPIs) is considered important, and their imbalance can potentially lead to type 2 inflammatory reactions, such as eCRS. In this review, we discuss various mechanisms by which exogenous proteases influence eCRS and highlight the emerging role of endogenous protease inhibitors in eCRS pathogenesis. Full article

The deformed wing virus (DWV) belongs to the genus Iflavirus and the family Iflaviridae within the order Picornavirales. It is an important pathogen of the Western honey bee, Apis mellifera, causing major losses among honey bee colonies in association with the ectoparasitic mite Varroa destructor. Although DWV is one of the best-studied insect viruses, the mechanisms of viral replication and polyprotein processing have been poorly studied in the past. We investigated the processing of the protease-polymerase region at the C-terminus of the polyprotein in more detail using recombinant expression, novel serological reagents, and virus clone mutagenesis. Edman degradation of purified maturated polypeptides uncovered the C- and N-termini of the mature 3C-like (3CL) protease and RNA-dependent RNA polymerase (3DL, RdRp), respectively. Autocatalytic processing of the recombinant DWV 3CL protease occurred at P1 Q₂₁₁₈ and P1′ G₂₁₁₉ (KPQ/GST) as well as P1 Q₂₃₉₃ and P1′ S₂₃₉₄ (HAQ/SPS) cleavage sites. New monoclonal antibodies (Mab) detected the mature 3CL protease with an apparent molecular mass of 32 kDa, mature 3DL with an apparent molecular mass of 55 kDa as well as a dominant 3CDL precursor of 90 kDa in DWV infected honey bee pupae. The observed pattern corresponds well to data obtained via recombinant expression and N-terminal sequencing. Finally, we were able to show that 3CL protease activity and availability of the specific protease cleavage sites are essential for viral replication, protein synthesis, and establishment of infection using our molecular clone of DWV-A. Full article

The thermostable protease TTHA0724 derived from Thermus thermophilus HB8 is an ideal industrial washing enzyme due to its thermophilic characteristics; although it can be expressed in Escherichia coli via pET-22b, high yields are difficult to achieve, leading to frequent autolysis of the host. This paper details the development of a signal peptide library in the expression system of B. subtilis and the optimization of signal peptides for enhanced extracellular expression of TTHA0724. When B. subtilis was used as the host and the optimized signal peptide was used, the expression level of TTHA0724 was 16.7 times higher compared with E. coli. B. subtilis as an expression host does not change the characteristics of TTHA0724. The potential application fields of TTHA0724 are studied. TTHA0724 can be used as a detergent additive at 60 °C, which can sterilize and eliminate mites while thoroughly cleaning protein stains. Soybean meal enzymatic hydrolysis with TTHA0724 at a high temperature produced a higher content of antioxidant peptides. These results indicate that TTHA0724 has great potential for industrial applications. Full article

Tick and mite infestations pose significant challenges to animal health, agriculture, and public health worldwide. The search for effective and environmentally friendly acaricidal agents has led researchers to explore natural alternatives. In this study, we investigated the acaricidal potential of the Monotheca buxifolia plant extract against Rhipicephalus microplus ticks and Sarcoptes scabiei mites. Additionally, we employed a computational approach to identify phytochemicals from the extract that could serve as drug candidates against these ectoparasites. The contact bioassay results demonstrated that the M. buxifolia plant extract exhibited significant efficacy against R. microplus and S. scabiei, with higher concentrations outperforming the positive control acaricide permethrin in terms of mite mortality. Time exposure to the extract also showed a positive correlation with better lethal concentration (LC₅₀ and LC₉₀) values. Similarly, the adult immersion test revealed a notable inhibition of tick oviposition via the plant extract, especially at higher concentrations. The two-protein primary structure, secondary structure and stability were predicted using the Expasy’s ProtParam server, SOPMA and SUSUI server, respectively. Using Homology modeling, the 3D structure of the protein was obtained and validated through the ERRAT server, and active sites were determined through the CASTp server. The docking analysis revealed that Alpha-Amyrenyl acetate and alpha-Tocopherol exhibited the highest docking scores for S. scabiei and R. microplus aspartic protease proteins, respectively. These phytochemicals demonstrated strong binding interactions, suggesting their potential as acaricidal drug candidates. In conclusion, the M. buxifolia plant extract displayed significant acaricidal activity against R. microplus and S. scabiei. Moreover, the computational approach identified promising phytochemicals that could serve as potential drug candidates for controlling these ectoparasites. Full article

Several plant papain-like cysteine proteases are exploited by the food, cosmetic, pharmaceutical and textile industries. However, some of these enzymes can cause allergic reactions. In this context, we investigated the frequency of sensitization and allergic reactions to some fruit and/or latex cysteine proteases, which are used as additives by the food industry to improve and modify the quality of their products. The FABER test was used to analyse the patients‘ sensitization towards five plants and, for comparison, two homologous mite cysteine proteases. In an Italian population of 341 allergic patients, 133 (39%) had IgE specific for at least one of the seven cysteine proteases under investigation. Most of the patients were IgE positive for Der p 1 and/or Der f 1 (96.38%) reported a clinical history suggestive of respiratory allergy to mites, whereas none of the subjects sensitized to the homologs from papaya, pineapple and fig reported allergy symptoms following ingestion of these foods. Only one patient referred symptoms from ingesting kiwifruit. Therefore, the obtained results showed that sensitization to the fruit enzymes was only rarely concomitant with allergic reactions. These observations, together with the literature reports, suggest that the allergy to plant papain-like cysteine proteases might mainly be an occupational disease. Full article

Group 1 protease allergens that persist in fecal particles from house dust mites (HDM) are the prevalent indoor aeroallergens and the primary triggers of dust mite allergy. Consequently, it is vital to discover a secure, efficient, affordable, and eco-friendly inhibitor to restrain these allergens. Herein, an assessment on the suppression of allergens Der f 1 and Der p 1 (predominant Group 1 allergens) with todomatsu oil derived from the remnants of Abies sachalinensis was performed using enzyme-linked immunosorbent assay (ELISA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and molecular docking analysis in silico. The results demonstrated that todomatsu oil effectively suppresses allergens Der f 1 and Der p 1 by lowering their allergen contents, and the decline rate rises with increasing todomatsu oil concentration. The formation of alkyl hydrophobic interactions, pi-sigma bonds, and hydrogen bonds have been observed between oil ingredients and allergens Der f 1 and Der p 1. Intriguingly, the majority of oil ingredients prefer to dock on hydrophobic amino acids. Additionally, oil ingredients docked to the cysteine protease site on Der f 1 or IgG epitope on Der p 1 were discovered. Notably, the binding affinity (BA) score and inhibition constant (Ki) revealed that bornyl acetate, the component with the maximum relative proportion in todomatsu oil, is included in the top five ingredients with the best inhibition effectiveness. As a result, todomatsu oil has been identified as an efficient inhibitor against Group 1 HDM allergens and a viable measure to improve indoor air quality. Full article

Emaravirus (Order Bunyavirales; Family Fimoviridae) is a genus comprising over 20 emerging plant viruses with a worldwide distribution and economic impact. Emaraviruses infect a variety of host plants and have especially become prevalent in important long-living woody plants. These viruses are enveloped, with a segmented, single-stranded, negative-sense RNA genome and are transmitted by eriophyid mites or mechanical transmission. Emaraviruses have four core genome segments encoding an RNA-dependent RNA polymerase, a glycoprotein precursor, a nucleocapsid protein, and a movement protein. They also have additional genome segments, whose number varies widely. We report here that the proteins encoded by these segments form three main homology groups: a homolog of the sadwavirus Glu2 Pro glutamic protease; a protein involved in pathogenicity, which we named “ABC”; and a protein of unknown function, which we named “P55”. The distribution of these proteins parallels the emaravirus phylogeny and suggests, with other analyses, that emaraviruses should be split into at least two genera. Reliable diagnosis systems are urgently needed to detect emaraviruses, assess their economic and ecological importance, and take appropriate measures to prevent their spread (such as routine testing, hygiene measures, and control of mite vectors). Additional research needs include understanding the function of emaravirus proteins, breeding resistant plants, and clarifying transmission modes. Full article

House dust mites (HDMs) are one of the most important allergy-causing agents of asthma. In central Taiwan, the prevalence of sensitization to Dermatophagoides microceras (Der m), a particular mite species of HDMs, is approximately 80% and is related to the IgE crossing reactivity of Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f). Integrated OMICs examination was used to identify and characterize the specific group 1 mite-allergic component (Der m 1). De novo draft genomic assembly and comparative genome analysis predicted that the full-length Der m 1 allergen gene is 321 amino acids in silico. Proteomics verified this result, and its recombinant protein production implicated the cysteine protease and α chain of fibrinogen proteolytic activity. In the sensitized mice, pathophysiological features and increased neutrophils accumulation were evident in the lung tissues and BALF with the combination of Der m 1 and 2 inhalation, respectively. Principal component analysis (PCA) of mice cytokines revealed that the cytokine profiles of the allergen-sensitized mice model with combined Der m 1 and 2 were similar to those with Der m 2 alone but differed from those with Der m 1 alone. Regarding the possible sensitizing roles of Der m 1 in the cells, the fibrinogen cleavage products (FCPs) derived from combined Der m 1 and Der m 2 induced the expression of pro-inflammatory cytokines IL-6 and IL-8 in human bronchial epithelium cells. Der m 1 biologically functions as a cysteine protease and contributes to the α chain of fibrinogen digestion in vitro. The combination of Der m 1 and 2 could induce similar cytokines expression patterns to Der m 2 in mice, and the FCPs derived from Der m 1 has a synergistic effect with Der m 2 to induce the expression of pro-inflammatory cytokines in human bronchial epithelium cells. Full article

Asthma is a chronic heterogeneous respiratory condition that is mainly associated with sensitivity to airborne agents such as pollen, dust mite products and fungi. Key pathological features include increased airway inflammation and airway wall remodelling. In particular, goblet cell hyperplasia, combined with excess mucus secretion, impairs clearance of the inhaled foreign material. Furthermore, structural changes such as subepithelial fibrosis and increased smooth muscle hypertrophy collectively contribute to deteriorating airway function and possibility of exacerbations. Current pharmacological therapies focused on airway wall remodelling are limited, and as such, are an area of unmet clinical need. Sensitisation to the fungus, Aspergillus fumigatus, is associated with enhanced asthma severity, bronchiectasis, and hospitalisation. How Aspergillus fumigatus may drive airway structural changes is unclear, although recent evidence points to a central role of the airway epithelium. This review provides an overview of the airway pathology in patients with asthma and fungal sensitisation, summarises proposed airway epithelial cell–fungal interactions and discusses the initiation of a tissue remodelling response. Related findings from in vivo animal models are included given the limited analysis of airway pathology in patients. Lastly, an important role for Aspergillus fumigatus-derived proteases in triggering a cascade of damage-repair events through upregulation of airway epithelial-derived factors is proposed. Full article

The two-spotted spider mite, Tetranychus urticae, also known as the red spider, is one of the most harmful pests in agriculture and causes large losses of many crops. These mites have rapidly developed a resistance to many chemical pesticides in recent years. In this study, the essential oil of seeds of the anise plant (Pimpinella anisum) was extracted by hydrodistillation, and the chemical composition of the oil was analyzed. The antioxidant activity of the volatile oil was determined by the DPPH radical scavenging assay. The acaricidal activity of the anise oil, a natural acaricide, was evaluated for its ability to protect green bean plants from mite injury. The two-spotted spiders were spread on green bean seedlings for 1 week; then, different plants were sprayed with different concentrations of anise oil (10, 20, 30, or 40 µL/L). Our results revealed that anethole was the major component of anise oil, at 53.23%. The acaricidal effect of the various concentrations on T. urticae was recorded after 24, 48, and 72 h of treatment. Our findings suggest that anise oil showed significant acaricidal activity against T. urticae in a dose- and time-dependent manner. Anise oil at a concentration of 40 µL/L killed 96.0% of the red spiders after 72 h. Also, all concentrations of anise oil inhibited acetylcholinesterase, and the spiders’ protease activity declined when the plants were treated with 30 or 40 µL/L of anise oil. The concentrations of 10 and 20 µL/L did not significantly affect the protease activity of T. urticae mites. We can conclude that anise oil exhibited acaricidal activity against T. urticae and that this was highly correlated with the inhibition of acetylcholinesterase and protease activities in the mites. Full article

Poultry red mite (PRM; Dermanyssus gallinae) is a hazardous, blood-sucking ectoparasite of birds that constitutes a threat to poultry farming worldwide. Acaricides, commonly used in poultry farms to prevent PRMs, are not effective because of the rapid emergence of acaricide-resistant PRMs. However, vaccination may be a promising strategy to control PRM. We identified a novel cystatin-like molecule in PRMs: Dg-Cys. Dg-Cys mRNA expression was detected in the midgut and ovaries, in all stages of life. The PRM nymphs that were artificially fed with the plasma from chickens that were immunized with Dg-Cys in vitro had a significantly reduced reproductive capacity and survival rate. Moreover, combination of Dg-Cys with other antigen candidates, like copper transporter 1 or adipocyte plasma membrane-associated protein, enhanced vaccine efficacies. vaccination and its application as an antigen for cocktail vaccines could be an effective strategy to reduce the damage caused by PRMs in poultry farming. Full article