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At least 19 recordsLinked to original sources
PubMed1979

Physostigmine: effects on fear or defense responses in the rat.

Previous research had shown that the anticholinergic drug, scopolamine, decreased innate defensive responses of rats to a live cat or mechanical robot, and that the effects of scopolamine were attributable to actions of the drug on the central nervous system. In the present research, the anticholinesterase, physostigmine, which increases central cholinergic activity, caused an increase in the defense responses of male hooded rats. Physostigmine caused significantly more freezing and significantly more suppression of feeding and suppression of time near the aversive stimulus (ROBOT). Dose-response curves showed a positive, linear relationship between dose (0.025, 0.05, 0.1 and 0.2 mg/kg) of physostigmine and defense responses. The present results could not be attributed to general response suppression since the effects of physostigmine were situation-specific, i.e., the drug had no significant effect on behavior in the non-aversive or NO ROBOT condition. The present results were taken as further evidence of the involvement of cholinergic activity in the mediation of defense responses. The effects of cholinergic and anticholinergic drugs on the observable defense response of freezing were thought to have important implications for the large literature relating these drugs and avoidance responding.

Aggression↗
PubMed2026

Molecular and transcriptional regulation of plant defense responses to aphid infestation.

Aphids are one of the important agricultural pests causing substantial yield losses in crops grown across the globe. Aphids are known to cause direct feeding damages and indirect losses due to sooty mold development and plant virus transmission. Plants respond to these attacks by mounting a complex defense response at the infested sites and systemic levels. This multilayered defense response involves a highly coordinated network of phytohormones and other signalling components like Ca2+, mitogen activated protein kinases and reactive oxygen species. Key to these complex responses is a well-regulated gene expression involving several transcription factors. A wide range of transcription factors are structurally and functionally characterized across some model plants and in a few agronomically important crops. These transcription factors play diverse roles such as defense gene expression modulation, regulation of hormone signaling, secondary metabolism, oxidative stress response, cell wall modifications, and phloem-based defense. Understanding the integration of signaling pathways, hormone crosstalk, and transcription factor mediated regulation provides a framework for practical applications, including breeding, genome editing, and elicitor-based strategies. This review highlights how plant defense signaling and transcriptional regulation against aphids can be harnessed to develop sustainable and novel pest management solutions.

Aphid↗
PubMed2026

The Key Trichoderma-Induced Gene Encoding a DUF568 Domain-Containing Protein Mediates Defense Responses in Wheat.

Genes encoding DUF568 domain-containing proteins participate in plant stress adaptation. To elucidate the functional role of DUF568 domain-containing genes in Trichoderma-induced wheat defense responses against wheat Fusarium crown rot, we performed a genome-wide identification and characterization of the TaDUF568 gene family in hexaploid wheat (Triticum aestivum L.). In this study, a total of 33 TaDUF568 family genes were systematically identified and characterized at the genome-wide level, exhibiting uneven chromosomal distribution and diverse physicochemical properties. Phylogenetic, structural, and collinearity analyses revealed conserved family characteristics among monocot species. Segmental duplication was verified as the primary driver of gene family expansion. Expression profiling revealed divergent tissue-specific expression patterns among TaDUF568 family members, among which TaDUF568.18 was strongly induced by Trichoderma M2. Subcellular localization assays confirmed that TaDUF568.18 is a plasma membrane-localized protein. Functional validation via stable transgenes demonstrated that overexpression of TaDUF568.18 restricted lesion expansion, improved agronomic traits, and enhanced disease resistance. This study is the first to characterize the wheat DUF568 family and confirm that TaDUF568.18 (annotated as TaAIR12) acts as a positive regulator of Trichoderma-mediated wheat defense, providing a valuable gene resource for wheat disease-resistance breeding.

DUF568↗
PubMed2024

Transcriptome analysis under pecan scab infection reveals the molecular mechanisms of the defense response in pecans.

Pecan scab, caused by the fungal pathogen Venturia effusa, is the most devastating disease of pecan (Carya illinoinensis) in the southeastern United States. Resistance to this pathogen is determined by a complex interaction between host genetics and disease pathotype with even field-susceptible cultivars being resistant to most scab isolates. To understand the underlying molecular mechanisms of scab resistance in pecan, we performed a transcriptome analysis of the pecan cultivar, 'Desirable', in response to inoculation with a pathogenic and a non-pathogenic scab isolate at three different time points (24, 48, and 96 hrs. post-inoculation). Differential gene expression and gene ontology enrichment analyses showed contrasting gene expression patterns and pathway enrichment in response to the contrasting isolates with varying pathogenicity. The weighted gene co-expression network analysis of differentially expressed genes detected 11 gene modules. Among them, two modules had significant enrichment of genes involved with defense responses. These genes were particularly upregulated in the resistant reaction at the early stage of fungal infection (24 h) compared to the susceptible reaction. Hub genes in these modules were predominantly related to receptor-like protein kinase activity, signal reception, signal transduction, biosynthesis and transport of plant secondary metabolites, and oxidoreductase activity. Results of this study suggest that the early response of pathogen-related signal transduction and development of cellular barriers against the invading fungus are likely defense mechanisms employed by pecan cultivars against non-virulent scab isolates. The transcriptomic data generated here provide the foundation for identifying candidate resistance genes in pecan against V. effusa and for exploring the molecular mechanisms of disease resistance.

Carya↗
PubMed2026

Biocontrol effect of a solid-state fermentation-derived extract mixture of Trichoderma asperellum on sunflower Sclerotinia rot and associated host defense responses.

Sclerotinia disease is a destructive fungal disease of sunflowers, soybeans, and other economically important crops, causing substantial yield loss and quality deterioration. Long-term reliance on dose-dependent broad-spectrum fungicides is constrained by resistance risks and potential environmental burdens, creating tension with the sustainability goal of "reducing pesticide use while improving efficacy." Here, we explore a Trichoderma spp.-based microbial disease management strategy. Whole-genome sequencing of Trichoderma asperellum TCS007 isolated from Antarctic marine sediments, coupled with genome mining, predicted diverse biosynthetic gene clusters putatively associated with siderophores, polyketides, nonribosomal peptides, and terpenoids; the corresponding metabolites are not chemically confirmed and require further validation. Using a solid-state fermentation workflow, we prepared a fermentation-derived extract mixture (TCS007-SSF-Ex). In vitro assays showed dose-dependent inhibition of Sclerotinia sclerotiorum by TCS007-SSF-Ex (EC50 = 1.252 mg/L), and microscopy revealed cellular damage-consistent changes, including organelle disruption and plasmolysis. Pathogen transcriptomic and metabolism-related analyses indicated broad perturbations in organelle biogenesis and metabolic processes, with significant alterations in pathways associated with succinate, D-glucose, and phenylacetate; these results are consistent with growth inhibition and reduced pathogenicity, but specific molecular targets and causal links remain to be validated. In vivo, under certain application conditions, triple applications increased APX activity (+492.5%) and β-1,3-glucanase activity (+419.6%). Collectively, this work supports a "pathogen suppression-host defense induction" framework and facilitates subsequent identification of active components and mechanistic validation.IMPORTANCESclerotinia diseases cause recurrent and economically important losses in oilseed crops, while long-term fungicide use is constrained by resistance risks and environmental burdens. Trichoderma-based biocontrol is a promising complementary strategy, yet evidence supporting metabolite-containing Trichoderma-derived preparations as immune elicitors remains less consolidated than that for living inoculants, and scalable production routes are still needed. Here, we examine an Antarctic marine sediment-derived strain, Trichoderma asperellum TCS007, and a solid-state fermentation (SSF)-derived extract mixture (TCS007-SSF-Ex) produced via solid-state fermentation. We combine in vitro antifungal assays, pathogen ultrastructural observations, and correlative omics analyses with in vivo measurements of sunflower defense enzymes (APX and β-1,3-glucanase) to evaluate a "pathogen suppression-host defense induction" framework. Our findings support the potential of SSF-derived Trichoderma metabolite mixtures for greener management of Sclerotinia disease and provide a foundation for future chemical identification of active components and mechanistic validation.

Ascomycota↗
PubMed2026

Liver transcriptome analysis revealed multiple immune processes and lipid metabolism pathways involved in the defense response of the turbot (Scophthalmus maximus) against Aeromonas salmonicida.

Aeromonas salmonicida is a significant pathogen causing notable economic losses in Scophthalmus maximus aquaculture. This study utilized Illumina sequencing technology to examine the transcriptional response characteristics of S. maximus liver at 24 h following A. salmonicida infection. A total of 2363 differentially expressed genes (DEGs) were identified when compared to the negative control group. The immunity-related Toll-like receptor signaling pathway, NOD-like receptor signaling pathway, as well as metabolism-related PPAR signaling pathway and insulin signaling pathway, were notably enriched. Significant differences exist in the expression of key genes within the PPAR pathway, particularly cd36, acsl4a, pparαa, and plin2, all of which mediate the interaction between lipid metabolism and the immune response. These results offer valuable insights into the immunometabolic regulatory mechanism of S. maximus response to A. salmonicida infection.

Animals↗
PubMed2025

Cell-type-specific response to silicon treatment in soybean leaves revealed by single-nucleus RNA sequencing and targeted gene editing.

Mineral nutrient uptake and deposition profoundly influence plant development, stress resilience, and productivity. Silicon (Si), though classified as a non-essential element, significantly influences a plant's physiology, particularly in fortifying defense responses and mitigating stress. While the genetic and molecular mechanisms of Si uptake and transport are well studied in monocots, particularly rice, their role in dicot species, such as soybean, remains unclear at the cellular and molecular levels. In this study, we utilized single-nucleus RNA sequencing (snRNA-seq) to dissect cellular responses to Si accumulation in soybean leaves. We identified distinct cellular populations, including a unique Si-induced or Si-associated cell cluster within vascular cells, suggesting a specialized mechanism of Si distribution. Si treatment notably induced the expression of defense-related genes, with a pronounced enrichment in vascular cells, underscoring their pivotal role in activating plant defense mechanisms. Moreover, Si modulated the expression of genes involved in phytoalexin biosynthesis, salicylic acid, and immune receptor signaling, suggesting transcriptional priming of genes involved in defense responses. Further investigation of Si transporters revealed precise expression of an Si efflux gene in epidermal cells in response to Si treatment. We also validated the role of efflux Si transporters using a Xenopus oocyte assay and CRISPR/Cas9 genome editing of composite soybean plant roots. This study provides critical insights into the biotic stress regulatory networks influenced by Si treatment in soybean leaves at the single-cell level, thus laying the foundation for enhancing stress tolerance through optimized mineral nutrient uptake.

Glycine max↗
PubMed1978

The measurement of assertiveness and aggressiveness.

The Bakker Assertiveness-Aggressiveness Inventory is a 36-item self-report inventory designed to measure two separate aspects of what has previously been subsumed under the rubric "assertiveness", namely, (a) defensive, responsive behaviors which protect territory and privileges, and (b) initiating behaviors which augment the person's territory or status. Assertiveness scores increases significantly above aggressiveness scores in a class which focused on the defensive, responsive aspects of behavior. Aggressiveness was found to correlate with occupation level and amount of schooling sought, while assertiveness did not correlate with either of these. Normative, reliability and validity data are presented.

Aggression↗
PubMed1978

Hemagglutinin-specific complement-dependent cytolytic antibody response to influenza infection.

The host defense response to influenza infection is complex. Specific humoral antibodies develop to the strain-specific surface antigens, the hemagglutinin and the neuraminidase, and to the internal antigens (matrix and nucleoprotein) which are common to all influenza A viruses (1). Antibodies to the hemagglutinin, which is the major surface antigen, neutralize viral infectivity (2). In addition to antibodies which have been detected against virion antigens, a cytotoxic T-cell response with specificity against the viral hemagglutinin on influenza-infected target cells (3-5) has been recently described. A more cross-reactive cytotoxic T-cell response has also been observed when a nonpermissively infected target cell is used in cytotoxicity assays (6,7). The present report describes the development during influenza infection and after vaccination of a cytolytic humoral antibody response which is directed against the hemagglutinin on infected target cells. This antibody-mediated lysis of infected cells in complement dependent, as has been reported with other virus infections (8-11).

Animals↗
PubMed1977

Mast cell-mediated reactions of host defense and tissue injury: the regulatory role of eosinophil polymorphonuclear leukocytes.

Immunological stimulation of mast cells, by way of either IgE- or IgG-directed reactions, initiates the rapid release of an array of chemical mediators. The predominant local tissue effects of these mediators collectively constitute a defensive response of the host. The early humoral phase of defense is exemplified by the alterations in microvascular permeability induced by histamine which provide a local concentration of immunoglobulins and complement components. The later cellular phase of defense is composed of the PMN leukocytes that accumulate in response to mast cell-derived chemotactic principles and which phagocytose and degrade opsonized foreign material, thus eliminating the inciting stimulus. Of the several endogenous regulatory mechanisms which act to contain the immediate hypersensitivity reaction, the eosinophil has a special role since it is specifically attracted to sites of mast cell activation and has selective concentrations of several enzymes which degrade the mast cell-derived chemical mediators. Failure of the local regulatory processes can permit the mast cell responses of host defense to become pathological reactions leading to tissue injury by virtue of persistence of high levels of humoral mediators and/or increasing infiltration with PMN leukocytes.

Anaphylaxis↗
PubMed2026

Genome-wide AP2/ERF analysis identifies HmaERF87 as a positive regulator of Hydrangea macrophylla leaf spot resistance.

A total of 164 APETALA2/ethylene-responsive factor (AP2/ERF) genes were identified in Hydrangea macrophylla, and HmaERF87 positively contributes to leaf spot resistance. The APETALA2/ethylene-responsive factor (AP2/ERF) transcription factor family plays important roles in plant stress responses, but its contribution to disease resistance in Hydrangea macrophylla (hydrangea) remains poorly understood. In this study, 164 AP2/ERF genes were identified in the H. macrophylla genome and classified into APETALA2 (AP2), ethylene-responsive factor (ERF), dehydration-responsive element-binding (DREB), and related to ABI3/VP1 (RAV) subfamilies. Their chromosomal distribution, conserved motifs, gene structures, and duplication patterns were analyzed. A total of 46 pathogen-responsive H. macrophylla AP2/ERF (HmaERF) genes were identified from the RNA sequencing (RNA-seq) dataset of resistant and susceptible cultivar leaves collected before and after Corynespora cassiicola inoculation. Promoter analysis revealed that the HmaERF genes with upregulated expression post-C. cassiicola infection showed a higher frequency and copy number of jasmonate-responsive cis-regulatory elements, suggesting their possible involvement in hormone-mediated defense responses. Three infection-induced candidate genes, including HmaERF56, HmaERF87, and HmaERF129, were selected for functional validation using virus-induced gene silencing (VIGS) in hydrangea leaf discs. Silencing of HmaERF87 expression via VIGS significantly increased lesion development after C. cassiicola inoculation, whereas the transient overexpression of HmaERF87 reduced the area of leaf disc lesions. Subcellular localization showed that the HmaERF87 protein was localized in the nucleus, and yeast assays indicated that its transcriptional activation activity was mainly associated with the C-terminal region of the protein. These results support a role for HmaERF87 as a positive regulator of H. macrophylla resistance to leaf spot disease and provide a candidate gene for further studies of disease resistance in hydrangea.

Plant Proteins↗
PubMed2026

Mechanisms of Transcriptional Regulation by Salicylic Acid Receptors.

Salicylic acid (SA) is a key phytohormone that activates plant defense responses 1-3. In Arabidopsis, NPR1 (also known as NIM1) and NPR3/NPR4 have been identified as dual SA receptors responsible for perceiving SA 4-6. However, the mechanisms of how SA binding to the NPR proteins leads to induction of defense gene expression remain unclear. Here, we elucidate how SA triggers transcriptional activation via NPR1 and relieves transcriptional repression mediated by NPR3/NPR4. We identified Mediator Complex Subunit 15A (MED15A) as a bridge between NPR1 and the Mediator complex governing transcription. SA induces direct interaction of NPR1 with MED15A. Structural and functional analysis showed that the binding of NPR1 to MED15A is essential for NPR1-mediated transcriptional activation. Meanwhile, SA relieves transcriptional repression mediated by NPR3/NPR4. NIM1-interacting 1 (NIMIN1) interacts with NPR3/NPR4 and the Topless (TPL) co-repressor, connecting them to Polycomb Repressive Complex 2 (PRC2) to mediate H3K27 trimethylation of SA-responsive genes. SA inhibits the interactions between NPR3/NPR4 and NIMIN1, reduces H3K27 trimethylation levels and increases histone acetylation of the target genes to release NPR3/NPR4-mediated repression. Our study offers a comprehensive view of SA-mediated defense gene activation. These findings lay a foundation for designing more effective SA analogs as agrochemicals and for engineering crop resistance by manipulating SA perception and signaling.

Journal Article↗
PubMed1979

Rejection of adenovirus 2-transformed cell tumors and immune responsiveness in Syrian hamsters.

Transplantation of adenovirus type 2-transformed cell-induced newborn tumor lines to different aged hamsters revealed that the cell-mediated host defenses responsible for tumor graft rejection matured early in the second week of life. When light microscopic examinations were performed during the course of tumor development, the primary histopathological difference between progressing tumors removed from newborn or thymectomized weanling hamsters and regressing lesions from normal weanlings was the lack of an early, mononuclear cell infiltrate in neoplasms from newborn and thymectomized hosts. These results suggest that the maturation of cellular immunity determines resistance to tumor transplantation in this system. This conclusion was supported by the in vitro detection of concanavalin A-responsive lymphocytes in spleens from tumor-resistant suckling but not tumor-susceptible neonatal hamsters. Although the incomplete seeding of thymus-dependent lymphocytes to the peripheral lymphoid tissues of newborn hamsters may partially explain the deficient concanavalin A responses of neonatal spleen cells, there appears to be an additional requirement for a radioresistant, adherent accessory cell population. These findings suggest that the development of a cell-mediated immune response is necessary for the rejection of adenovirus type 2-transformed cells and transformed cell-induced tumors and that this response requires the interaction of T-cells and accessory cell populations.

Adenoviridae↗
PubMed2025

GhDMT7-mediated DNA methylation dynamics enhance starch and sucrose metabolism pathways to confer salt tolerance in cotton.

This study provides a comprehensive analysis of the impact of DNA methylation in cotton under salt stress conditions, elucidating its effects on gene expression and biological processes. Here, we determined the structures of the DNA methylation landscape across the cotton genome subjected to salt stress using whole-genome bisulfite sequencing (WGBS) and RNA-seq methodologies. We identified 4938 differentially methylated regions (DMRs) correlated with alterations in gene expression. Salt stress induced significant shifts in DNA methylation patterns, particularly in CHH contexts, suggesting context-dependent epigenetic regulation. DMRs were found to be implicated in diverse biological processes and pathways, encompassing protein metabolism, cellular homeostasis, starch and sucrose metabolism, and plant hormone signaling, all pivotal for cotton's adaptation to salt stress. Furthermore, RNA-seq analysis confirmed the impact of DNA methylation on gene expression, uncovering 9642 salt stress-responsive differentially expressed genes (DEGs). These DEGs exhibited enrichment in pathways such as carbohydrate metabolism, cell wall synthesis, and defense response, underscoring the intricate interplay between methylation and gene regulation in stress response. Moreover, the study investigated the role of the key DNA methyltransferase gene GhDMT7 in modulating cotton's response to salt stress, revealing that its downregulation enhanced cotton's salt tolerance, potentially attributed to decreased DNA methylation levels, reduced membrane damage, and enhanced antioxidant capacity. These findings elucidate the role of DNA methylation in abiotic stress resilience and provide insights for crop improvement.

Gossypium↗
PubMed1979

Adrenergic modulation of the hypothalamic cholinergic mechanism in the control of emotional-defensive behavior in the cat.

Effects of drugs influencing the activity of the hypothalamic noradrenergic system on the carbachol-induced emotional-defensive response were investigated. Intrahypothalamic injections of noradrenalin, amphetamine and reserpine did not produce any changes in cats' behavior. Injections of carbachol into the same hypothalamic loci, following the injections of noradrenalin, amphetamine or reserpine evoked all the characteristic symptoms of emotional-defensive behavior. However, a strong decrease in the number of growls and the duration of growling was observed when reserpine injections preceded the injections of carbachol into the same hypothalamic areas. Adrenergic alpha and beta agonists (methoxamine and isoprenaline) as well as antagonists (phentolamine and oxprenolol) when injected alone had no influence on the cats' behavior. Their effect on vocal responses evoked by subsequent injections of carbachol was not statistically significant. Results show that emotional-defensive behavior cannot be triggered by an activation of the hypothalamic noradrenergic system. However, emotional defensive behavior induced by cholinergic stimulation of the hypothalamus may be modified by changes in the activity of the hypothalamic noradrenergic system.

Animals↗
PubMed2026

The bZIP54 (GBF2)-SARD1 module regulates salicylic acid-mediated resistance to Pst DC3000 in Arabidopsis.

Salicylic acid (SA)-mediated defense responses are crucial for plant immunity, yet transcription factors (TFs) that coordinate SA biosynthesis with immune activation remain incompletely characterized. Here, a basic leucine zipper (bZIP) TF, bZIP54, was identified as a positive regulator in response to Pseudomonas syringae pv. tomato (Pst) DC3000. Consistent with this finding, bZIP54 regulated SA accumulation and a suite of SA-related defense genes following Pst DC3000 infection. Mechanistically, bZIP54 directly bound to a G-box-like motif in the SARD1 promoter, activating its expression-an interaction that was further enhanced by SA. Genetic analysis demonstrated that SARD1 operates downstream of bZIP54 to confer resistance to Pst DC3000. Additionally, bZIP54 also contributed to defense against the fungal pathogen Sclerotinia sclerotiorum, indicating a broader role in plant immunity. Together, these findings revealed a bZIP54-SARD1 regulatory module, thus providing insights into the transcriptional networks governing disease resistance in Arabidopsis.

Arabidopsis↗
PubMed1976

Action of enpiprazole on emotional behavior induced by hypothalamic stimulation in rats and cats.

Action of enpiprazole on emotional behavior elicited by hypothalamic stimulation in rats and cats was investigated and comparisons were made with effects of diazepam. Two behavioral patterns were elicited by stimulation of the postero-medial part of the hypothalamus in rats: a food-carrying response beginning with exploratory movement and an analogue of fear. Enpiprazole frequently changed the food-carrying response into food-taking response and occasionally analogues of fear into food-carrying and /or food-taking responses. Thresholds for these behaviors were also elevated. Diazepam showed the same effects on the thresholds as enpiprazole, having but little effect on the behavioral patterns. In cats, enpiprazole evelvated the thresholds for affective-defensive responses induced by hypothalamic stimulation in 6 of 8 cases, but lowered them in 2 cases. This suggests that enpiprazple has a 'biphasic effect' in the central nervous system. By contrast,diazepam consistently elevated thresholds. Comparing the action of enpiprazole with that of diazepam it can be presumed that the former is a different type of anxiolytic drug than the latter.

Animals↗