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Frontiers in Plant Science 2020The molecular basis of plant immunity triggered by microbial pathogens is being well-characterized as a complex sequential process leading to the activation of defense... (Review)
Review
The molecular basis of plant immunity triggered by microbial pathogens is being well-characterized as a complex sequential process leading to the activation of defense responses at the infection site, but which may also be systemically expressed in all organs, a phenomenon also known as systemic acquired resistance (SAR). Some plant-associated and beneficial bacteria are also able to stimulate their host to mount defenses against pathogen ingress via the phenotypically similar, induced systemic resistance phenomenon. Induced systemic resistance resembles SAR considering its mechanistic principle as it successively involves recognition at the plant cell surface, stimulation of early cellular immune-related events, systemic signaling via a fine-tuned hormonal cross-talk and activation of defense mechanisms. It thus represents an indirect but efficient mechanism by which beneficial bacteria with biocontrol potential improve the capacity of plants to restrict pathogen invasion. However, according to our current vision, induced systemic resistance is specific considering some molecular aspects underpinning these different steps. Here we overview the chemical diversity of compounds that have been identified as induced systemic resistance elicitors and thereby illustrating the diversity of plants species that are responsive as well as the range of pathogens that can be controlled via this phenomenon. We also point out the need for further investigations allowing better understanding how these elicitors are sensed by the host and the diversity and nature of the stimulated defense mechanisms.
PubMed: 33304371
DOI: 10.3389/fpls.2020.594530 -
Infection and Immunity Jun 2020Neutrophils kill invading microbes and therefore represent the first line of defense of the innate immune response. Activated neutrophils assemble NADPH oxidase to... (Review)
Review
Neutrophils kill invading microbes and therefore represent the first line of defense of the innate immune response. Activated neutrophils assemble NADPH oxidase to convert substantial amounts of molecular oxygen into superoxide, which, after dismutation into peroxide, serves as the substrate for the generation of the potent antimicrobial hypochlorous acid (HOCl) in the phagosomal space. In this minireview, we explore the most recent insights into physiological consequences of HOCl stress. Not surprisingly, Gram-negative bacteria have evolved diverse posttranslational defense mechanisms to protect their proteins, the main targets of HOCl, from HOCl-mediated damage. We discuss the idea that oxidation of conserved cysteine residues and partial unfolding of its structure convert the heat shock protein Hsp33 into a highly active chaperone holdase that binds unfolded proteins and prevents their aggregation. We examine two novel members of the chaperone holdase family, RidA and CnoX, whose thiol-independent activation mechanism differs from that of Hsp33 and requires N-chlorination of positively charged amino acids during HOCl exposure. Furthermore, we summarize the latest findings with respect to another bacterial defense strategy employed in response to HOCl stress, which involves the accumulation of the universally conserved biopolymer inorganic polyphosphate. We then discuss sophisticated adaptive strategies that bacteria have developed to enhance their survival during HOCl stress. Understanding bacterial defense and survival strategies against one of the most powerful neutrophilic oxidants may provide novel insights into treatment options that potentially compromise the ability of pathogens to resist HOCl stress and therefore may increase the efficacy of the innate immune response.
Topics: Bacteria; Bacterial Infections; Bacterial Physiological Phenomena; Defense Mechanisms; Humans; Hypochlorous Acid; Microbial Viability; Molecular Chaperones; Neutrophils; Oxidants; Oxidation-Reduction; Oxidative Stress; Protein Binding; Respiratory Burst; Structure-Activity Relationship
PubMed: 32152198
DOI: 10.1128/IAI.00964-19 -
PloS One 2023The poultry red mite, Dermanyssus gallinae (Mesostigmata: Dermanyssidae), is a major pest that causes great damage to chicken egg production. In one of our previous...
The poultry red mite, Dermanyssus gallinae (Mesostigmata: Dermanyssidae), is a major pest that causes great damage to chicken egg production. In one of our previous studies, the management of red mites using entomopathogenic fungi was evaluated, and the acaricidal fungus Beauveria bassiana JEF-410 was selected for further research. In this study, we tried to elucidate the pathogenesis of B. bassiana JEF-410 and the defense mechanisms of red mites at a transcriptome level. Red mites collected from a chicken farm were treated with B. bassiana JEF-410. When the mortality of infected red mites reached 50%, transcriptome analyses were performed to determine the interaction between B. bassiana JEF-410 and red mites. Uninfected red mites and non-infecting fungus served as controls. In B. bassiana JEF-410, up-regulated gene expression was observed in tryptophan metabolism and secondary metabolite biosynthesis pathways. Genes related to acetyl-CoA synthesis were up-regulated in tryptophan metabolism, suggesting that energy metabolism and stress management were strongly activated. Secondary metabolites associated with fungal up-regulated DEGs were related to the production of substances toxic to insects such as beauvericin and beauveriolide, efflux pump of metabolites, energy production, and resistance to stress. In red mites, physical and immune responses that strengthen the cuticle against fungal infection were highly up-regulated. From these gene expression analyses, we identified essential factors for fungal infection and subsequent defenses of red mites. These results will serve as a strong platform for explaining the interaction between B. bassiana JEF-410 and red mites in the stage of active infection.
Topics: Animals; Poultry; Beauveria; Tryptophan; Mites; Trombiculidae; Chickens; Defense Mechanisms; Poultry Diseases; Mite Infestations
PubMed: 36800366
DOI: 10.1371/journal.pone.0280410 -
International Journal of Molecular... Oct 2022Cotton is an important economic crop. and are the primary pathogenic fungi that threaten both the quality and sustainable production of cotton. As an opportunistic... (Review)
Review
Cotton is an important economic crop. and are the primary pathogenic fungi that threaten both the quality and sustainable production of cotton. As an opportunistic pathogen, causes various human diseases, including fungal keratitis, which is the most common. Therefore, there is an urgent need to study and clarify the resistance mechanisms of cotton and humans toward in order to mitigate, or eliminate, its harm. Herein, we first discuss the resistance and susceptibility mechanisms of cotton to and wilt and classify associated genes based on their functions. We then outline the characteristics and pathogenicity of and describe the multiple roles of human neutrophils in limiting hyphal growth. Finally, we comprehensively compare the similarities and differences between animal and plant resistance to and put forward new insights into novel strategies for cotton disease resistance breeding and treatment of infection in humans.
Topics: Humans; Verticillium; Fusarium; Plant Diseases; Plant Breeding; Disease Resistance; Gossypium; Defense Mechanisms
PubMed: 36293072
DOI: 10.3390/ijms232012217 -
International Journal of Molecular... Sep 2023Being the major cellular component of highly dynamic tissue, endometrial stromal cells (EnSCs) are exposed to cycles of proliferation upon hormonal stimulation, which...
Being the major cellular component of highly dynamic tissue, endometrial stromal cells (EnSCs) are exposed to cycles of proliferation upon hormonal stimulation, which might pose risks for the accumulation of mutations and malignization. However, endometrial stromal tumors are rare and uncommon. The present study uncovered defense mechanisms that might underlie the resistance of EnSCs against oncogenic transformation. All experiments were performed in vitro using the following methods: FACS, WB, RT-PCR, IF, molecular cloning, lentiviral transduction, and CRISPR/Cas9 genome editing. We revealed that the expression of the mutant HRAS leads to EnSC senescence. We experimentally confirmed the inability of HRAS-expressing EnSCs to bypass senescence and resume proliferation, even upon estrogen stimulation. At the molecular level, the induction of oncogene-induced senescence (OIS) was accompanied by activation of the MEK/ERK, PI3K/AKT, p53/p21/Rb, and p38/p16/Rb pathways; however, inhibiting either pathway did not prevent cell cycle arrest. PTEN loss was established as an additional feature of HRAS-induced senescence in EnSCs. Using CRISPR-Cas9-mediated PTEN knockout, we identified PTEN loss-induced senescence as a reserve molecular mechanism to prevent the transformation of HRAS-expressing EnSCs. The present study highlights oncogene-induced senescence as an antitumor defense mechanism of EnSCs controlled by multiple backup molecular pathways.
Topics: Humans; Phosphatidylinositol 3-Kinases; Cloning, Molecular; Stromal Cells; Defense Mechanisms; Oncogenes
PubMed: 37762392
DOI: 10.3390/ijms241814089 -
International Journal of Environmental... Oct 2022Emotion regulation is an important aspect of psychological functioning that influences subjective experience and moderates emotional responses throughout the lifetime....
Emotion regulation is an important aspect of psychological functioning that influences subjective experience and moderates emotional responses throughout the lifetime. Adaptive responses to stressful life events depend on the positive interaction between explicit and implicit emotion regulation strategies, such as mindfulness and defense mechanisms. This study demonstrates how these emotion regulation strategies predict psychological health during the early phase of the COVID-19 pandemic. A convenience sample of 6385 subjects, recruited via snowball sampling on various social media platforms, responded to an online survey assessing psychological reaction to social restrictions imposed to limit the spread of COVID-19 in Italy. Psychological distress, post-traumatic stress symptoms, mindfulness, and defense mechanisms were assessed using SCL-90, IES-R, MAAS, and DMRS-30-SR, respectively. Higher mindfulness was significantly associated with higher overall defensive maturity and a greater use of high-adaptive defenses ( < 0.0001). Both mindfulness and defense mechanisms acted as good predictors of psychological health (R = 0.541) and posttraumatic symptoms (R = 0.332), confirming the role of emotion regulation in protecting against maladaptive responses to stressful situations.
Topics: COVID-19; Defense Mechanisms; Emotional Regulation; Humans; Mindfulness; Pandemics; Psychological Distress
PubMed: 36231993
DOI: 10.3390/ijerph191912690 -
Veterinary Research 2000The objective of this study was to review the possible relationships between hyperketonemia and the function of phagocytes with respect to the bovine udder defense... (Review)
Review
The objective of this study was to review the possible relationships between hyperketonemia and the function of phagocytes with respect to the bovine udder defense mechanism. We hypothesize that an increased incidence of clinical mastitis in high-producing cows is caused by the impairment of the udder defense mechanism during hyperketonemia. First, we review the acute phase of udder defense mechanisms after intramammary infection. The physiological changes of cows in negative energy balance are subsequently discussed. Finally, possible relationships between udder defense and physiological changes during negative energy balance, especially hyperketonemia, are reviewed. The three stages of an acute phase of udder defense are: (1) immediately eliminating invading pathogens by phagocytes, (2) releasing inflammatory substances, especially chemoattractants, and (3) migration of polymorphonuclear leukocytes into the infected udder. Leukocytes from hyperketonemia subjects show a lower capacity of the phagocytic defense mechanism. In addition, the phagocytic and bactericidal capacities of neutrophils are reduced when these cells are acting in the presence of high concentrations of ketone bodies. Lower amounts of cytokine production after bacterial infection are observed in ketotic subjects. The chemotactic capacity of blood leukocytes is impaired in leukocytes obtained from ketotic cows. Lower numbers of blood leukocytes are observed in ketotic cows. In conclusion, the impairment of the udder defense mechanism in negative energy balance cows seems related to hyperketonemia.
Topics: Animals; Cattle; Female; Ketone Bodies; Lactation; Leukocytes; Mammary Glands, Animal; Mastitis, Bovine; Phagocytosis
PubMed: 10958241
DOI: 10.1051/vetres:2000128 -
Neuron Jul 2019The neural basis of defensive behaviors continues to attract much interest, not only because they are important for survival but also because their dysregulation may be... (Review)
Review
The neural basis of defensive behaviors continues to attract much interest, not only because they are important for survival but also because their dysregulation may be at the origin of anxiety disorders. Recently, a dominant approach in the field has been the optogenetic manipulation of specific circuits or cell types within these circuits to dissect their role in different defensive behaviors. While the usefulness of optogenetics is unquestionable, we argue that this method, as currently applied, fosters an atomistic conceptualization of defensive behaviors, which hinders progress in understanding the integrated responses of nervous systems to threats. Instead, we advocate for a holistic approach to the problem, including observational study of natural behaviors and their neuronal correlates at multiple sites, coupled to the use of optogenetics, not to globally turn on or off neurons of interest, but to manipulate specific activity patterns hypothesized to regulate defensive behaviors.
Topics: Animals; Brain; Defense Mechanisms; Extinction, Psychological; Fear; Humans; Individuality; Neural Pathways; Neurons; Optogenetics
PubMed: 31319049
DOI: 10.1016/j.neuron.2019.05.024 -
BMJ Open Respiratory Research Jul 2023Epidemiological and clinical studies have indicated an association between particulate matter (PM) exposure and acute and chronic pulmonary inflammation, which may be... (Review)
Review
Epidemiological and clinical studies have indicated an association between particulate matter (PM) exposure and acute and chronic pulmonary inflammation, which may be registered as increased mortality and morbidity. Despite the increasing evidence, the pathophysiology mechanism of these PMs is still not fully characterised. Pulmonary alveolar macrophages (PAMs), as a predominant cell in the lung, play a critically important role in these pathological mechanisms. Toxin exposure triggers events associated with macrophage activation, including oxidative stress, acute damage, tissue disruption, remodelling and fibrosis. Targeting macrophage may potentially be employed to treat these types of lung inflammation without affecting the natural immune response to bacterial infections. Biological toxins, their sources of exposure, physical and other properties, and their effects on the individuals are summarised in this article. Inhaled particulates from air pollution and toxic gases containing chemicals can interact with alveolar epithelial cells and immune cells in the airways. PAMs can sense ambient pollutants and be stimulated, triggering cellular signalling pathways. These cells are highly adaptable and can change their function and phenotype in response to inhaled agents. PAMs also have the ability to polarise and undergo plasticity in response to tissue damage, while maintaining resistance to exposure to inhaled agents.
Topics: Humans; Macrophages, Alveolar; Air Pollution; Gases; Lung; Defense Mechanisms
PubMed: 37479504
DOI: 10.1136/bmjresp-2022-001589 -
BMC Psychology Nov 2023Adolescence is recognized as a particularly susceptible developmental period for experiencing multiple types of Adverse Childhood Experiences (ACE), increasing the...
BACKGROUND
Adolescence is recognized as a particularly susceptible developmental period for experiencing multiple types of Adverse Childhood Experiences (ACE), increasing the vulnerability to higher levels of Post-Traumatic Stress Disorder (PTSD) and Complex PTSD symptoms. Some studies found that defense mechanisms play an important role on the association between ACE and psychological symptoms.
METHODS
We analyzed the associations between direct and indirect exposure to ACE and PTSD and Complex PTSD (affective dysregulation, negative self-concept and disturbances in relationships) through the mediation role of mature defense mechanisms: mature, neurotic, and immature defense mechanisms in Indian adolescents. A sample of 411 Indian adolescents (M = 14.2 years old; S.D. = 0.5) completed validated self-report questionnaires. Serial multiple mediation models were tested by conducting a structural equation modelling employing Preacher and Hayes' procedures (2008).
RESULTS
Immature and neurotic defense mechanisms mediated the association between direct exposure to ACE with PTSD symptoms. Immature defense mechanisms were mediators of the relationship between direct exposure to ACE and Complex PTSD symptoms clusters.
CONCLUSIONS
Maladaptive defense mechanisms can disturb the process of self-regulation and emotion regulation capabilities in coping with traumatic experiences, leading to higher PTSD and Complex PTSD symptoms severity.
Topics: Humans; Adolescent; Stress Disorders, Post-Traumatic; Adaptation, Psychological; Emotional Regulation; Surveys and Questionnaires; Defense Mechanisms
PubMed: 38001536
DOI: 10.1186/s40359-023-01456-0