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Microbiology Spectrum Apr 2016Invading pathogens are exposed to a multitude of harmful conditions imposed by the host gastrointestinal tract and immune system. Bacterial defenses against these... (Review)
Review
Invading pathogens are exposed to a multitude of harmful conditions imposed by the host gastrointestinal tract and immune system. Bacterial defenses against these physical and chemical stresses are pivotal for successful host colonization and pathogenesis. Enteric pathogens, which are encountered due to the ingestion of or contact with contaminated foods or materials, are highly successful at surviving harsh conditions to colonize and cause the onset of host illness and disease. Pathogens such as Campylobacter, Helicobacter, Salmonella, Listeria, and virulent strains of Escherichia have evolved elaborate defense mechanisms to adapt to the diverse range of stresses present along the gastrointestinal tract. Furthermore, these pathogens contain a multitude of defenses to help survive and escape from immune cells such as neutrophils and macrophages. This chapter focuses on characterized bacterial defenses against pH, osmotic, oxidative, and nitrosative stresses with emphasis on both the direct and indirect mechanisms that contribute to the survival of each respective stress response.
Topics: Adaptation, Physiological; Animals; Bacteria; Bacterial Physiological Phenomena; Defense Mechanisms; Gastrointestinal Tract; Humans; Microbial Viability; Stress, Physiological; Virulence
PubMed: 27227312
DOI: 10.1128/microbiolspec.VMBF-0007-2015 -
Current Biology : CB Nov 2023The aerial surfaces of quinoa (Chenopodium quinoa) and common ice plant (Mesembryanthemum crystallinum) are covered with a layer of epidermal bladder cells (EBCs), which...
The aerial surfaces of quinoa (Chenopodium quinoa) and common ice plant (Mesembryanthemum crystallinum) are covered with a layer of epidermal bladder cells (EBCs), which are modified non-glandular trichomes previously considered to be key to the extreme salt and drought tolerance of these plants. Here, however, we find that EBCs of these plants play only minor roles, if any, in abiotic stress tolerance and in fact are detrimental under conditions of water deficit. We report that EBCs instead function as deterrents to a broad range of generalist arthropod herbivores, through their combined function of forming both a chemical and a physical barrier, and they also serve a protective function against a phytopathogen. Our study overturns current models that link EBCs to salt and drought tolerance and assigns new functions to these structures that might provide novel possibilities for protecting crops from arthropod pests.
Topics: Herbivory; Urinary Bladder; Sodium Chloride; Plants; Defense Mechanisms
PubMed: 37852262
DOI: 10.1016/j.cub.2023.09.063 -
Translational Psychiatry Jan 2023Despite the clinical relevance of defense mechanisms, there are no published studies in nationally representative samples of their prevalence, correlates, and...
Despite the clinical relevance of defense mechanisms, there are no published studies in nationally representative samples of their prevalence, correlates, and association with psychosocial functioning. We sought to estimate the prevalence and correlates of 12 defense mechanisms in the general adult population by approximating from items used to assess personality traits in the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a representative sample of US adults (N = 36,653). We examined the associations between sociodemographic characteristics and prevalence of 3 types of defenses mechanisms (pathological, immature, and neurotic). For each defense mechanism, we used the Short-Form 12 to compare psychosocial functioning among 3 groups: those who (1) endorsed the mechanism with self-recognized impairment, (2) endorsed the mechanism without self-recognized impairment, and (3) did not endorse the defense mechanism. The prevalence of defense mechanisms ranged from 13.2% (splitting) to 44.5% (obsessive/controlling behavior). Pathological defenses were more strongly associated with immature defenses (OR = 5.4, 95% CI = 5.2-5.6) than with neurotic defenses (OR = 2.0, 95% CI = 1.9-2.0), whereas the association between immature and neurotic defenses had an intermediate value between the other two (OR = 2.2, 95% CI = 2.1-2.2). Pathological and immature defenses were associated with younger age, having been never married, lower educational attainment, and lower income. After adjusting the crude results for age and sex, individuals who did not endorse a given defense generally had higher scores on the mental health component of the SF-12 than those who endorsed the defense without self-recognized impairment who, in turn, had on average higher scores than those with self-recognized impairment. These results suggest that neurotic, immature, and pathological defense mechanisms are prevalent in the general population and associated with psychosocial impairment. Recognizing defense mechanisms may be important in clinical practice regardless of treatment modality.
Topics: Humans; Adult; Defense Mechanisms; Prevalence; Surveys and Questionnaires
PubMed: 36690611
DOI: 10.1038/s41398-022-02303-3 -
Medical Science Monitor : International... Jun 2015It is a struggle to identify the most adaptive coping strategies with disease-mediated stress. Here, we hypothesize that intensity of coping strategies, including...
BACKGROUND
It is a struggle to identify the most adaptive coping strategies with disease-mediated stress. Here, we hypothesize that intensity of coping strategies, including denial, in patients with end-stage renal disease (ESRD), varies with type of renal replacement therapy (RRT).
MATERIAL AND METHODS
We enrolled 60 in-center hemodialyzed patients (HD) and 55 patients treated with continuous ambulatory peritoneal dialysis (CAPD). We administered the Coping Inventory with Stressful Situation, Profile of Mood States, and Stroop Anxiety Inventory to measure patient coping strategies in the context of their ESRD. Denial defense mechanism was measured via the IBS-R/ED. The Nottingham Health Profile was used to evaluate self-perceived quality of life. Serum potassium, urea, creatinine, phosphorus, calcium, albumin, and hematocrit were utilized as the measurements of adequacy of dialysis.
RESULTS
HD patients had higher self-reported intensity of denial mechanism and avoidance-oriented strategies versus CAPD patients. Because a single strategy is almost never employed, we conducted cluster analysis. We identify 3 patterns of coping strategies using cluster analysis. "Repressors" employed denial and avoidance strategies and were predominant in HD. The second cluster consists of subjects employing predominantly task-oriented strategies with equal distribution among dialyzed patients. The third cluster encompassed a small group of patients who shared higher intensity of both denial and task-oriented strategies. Health-related outcome, anxiety, and mood profile were similar across all patients.
CONCLUSIONS
HD patients predominantly used "repressive" strategies. Patients on RRT utilized denial and avoidance-based strategies to achieve satisfactory outcome in terms of perceived quality of life. We conclude that these coping mechanisms that were previously thought to be inferior are beneficial to patient compliance with RRT.
Topics: Adaptation, Psychological; Adult; Affect; Aged; Albumins; Anxiety; Calcium; Cohort Studies; Creatinine; Cross-Sectional Studies; Denial, Psychological; Female; Hematocrit; Humans; Kidney Failure, Chronic; Male; Middle Aged; Peritoneal Dialysis, Continuous Ambulatory; Phosphorus; Potassium; Quality of Life; Renal Dialysis; Statistics, Nonparametric; Urea
PubMed: 26094792
DOI: 10.12659/MSM.893331 -
Insects Apr 2022With the wide-scale adoption of transgenic (Bt) cotton, (Meyer-Dür) has become the most serious pest and has caused extensive yield loss in cotton production....
With the wide-scale adoption of transgenic (Bt) cotton, (Meyer-Dür) has become the most serious pest and has caused extensive yield loss in cotton production. However, little is known about the defense responses of cotton at the seedling stage to feeding. In this study, to elucidate the cotton defense mechanism, cotton leaves were damaged by for 0, 4, 12 and 24 h. The transcriptomic results showed that feeding elicits a rapid and strong defense response in gene expression during the whole infestation process in cotton plants. Further analysis revealed that at each assessment time, more differentially expressed genes were up-regulated than down-regulated. The integrated analysis of transcriptomic and metabolic data showed that most of the genes involved in jasmonic acid (JA) biosynthesis were initially up-regulated, and this trend continued during an infestation. Meanwhile, the content levels of JA and its intermediate products were also significantly increased throughout the whole infestation process. The similar trend was displayed in condensed tannins biosynthesis. This research proved that, after plants are damaged by , the JA pathway mediates the defense mechanisms in cotton plants by promoting the accumulation of condensed tannins as a defense mechanism against . These results will help us to discover unknown defensive genes and improve the integrated pest management of .
PubMed: 35447833
DOI: 10.3390/insects13040391 -
American Journal of Public Health Mar 2022
Topics: Adolescent; Gender Identity; Humans; Transgender Persons; Transsexualism
PubMed: 35196055
DOI: 10.2105/AJPH.2021.306690 -
MSystems Oct 2023Microbiology conferences can be powerful places to build collaborations and exchange ideas, but for queer and transgender (trans) scientists, they can also become...
Microbiology conferences can be powerful places to build collaborations and exchange ideas, but for queer and transgender (trans) scientists, they can also become sources of alienation and isolation. Many conference organizers would like to create welcoming and inclusive events but feel ill-equipped to make this vision a reality, and a historical lack of representation of queer and trans folks in microbiology means we rarely occupy these key leadership roles ourselves. Looking more broadly, queer and trans scientists are systematically marginalized across scientific fields, leading to disparities in career outcomes, professional networks, and opportunities, as well as the loss of unique scientific perspectives at all levels. For queer and trans folks with multiple, intersecting, marginalized identities, these barriers often become even more severe. Here, we draw from our experiences as early-career microbiologists to provide concrete, practical advice to help conference organizers across research communities design inclusive, safe, and welcoming conferences, where queer and trans scientists can flourish.
Topics: Humans; Transgender Persons; Sexual and Gender Minorities; Gender Identity; Transsexualism
PubMed: 37800938
DOI: 10.1128/msystems.00433-23 -
Frontiers in Psychology 2022When shame and guilt emotional experiences related to stressful events remain unresolved, they can be related to psychological impairment and recursive thoughts. The...
When shame and guilt emotional experiences related to stressful events remain unresolved, they can be related to psychological impairment and recursive thoughts. The present study aims to explore the association between state shame and state guilt related to past stressful experiences and psychopathological symptoms and evaluating a mediation role by immature defenses. A total of 90 participants (48.9% female; mean age 23.66) were considered in the present study to (a) investigate correlations between state guilt and shame scores related to personal stressful events and psychopathological symptoms related to global severity index; (b) assess whether state guilt and shame scores related to personal stressful events are positively correlated with immature defenses; (c) test whether immature defenses mediates the relationship between, respectively, state shame and state guilt with psychopathological symptoms. Significant correlations between state shame, state guilt, psychopathological symptoms, and immature defenses were found. Higher activations on immature defenses partially mediated the relationship between psychopathological symptoms and state shame and state guilt, respectively. Past experiences related to shame and guilt should be targeted by specific treatments that could help stop recursive maladaptive thoughts and empower more adaptive defensive strategies.
PubMed: 35592158
DOI: 10.3389/fpsyg.2022.832237 -
ELife Aug 2022Bacteria use diverse immunity mechanisms to defend themselves against their viral predators, bacteriophages. In turn, phages can acquire counter-defense systems, but it...
Bacteria use diverse immunity mechanisms to defend themselves against their viral predators, bacteriophages. In turn, phages can acquire counter-defense systems, but it remains unclear how such mechanisms arise and what factors constrain viral evolution. Here, we experimentally evolved T4 phage to overcome a phage-defensive toxin-antitoxin system, , in . Through recombination, T4 rapidly acquires segmental amplifications of a previously uncharacterized gene, now named , encoding an inhibitor of the toxin, ToxN. These amplifications subsequently drive large deletions elsewhere in T4's genome to maintain a genome size compatible with capsid packaging. The deleted regions include accessory genes that help T4 overcome defense systems in alternative hosts. Thus, our results reveal a trade-off in viral evolution; the emergence of one counter-defense mechanism can lead to loss of other such mechanisms, thereby constraining host range. We propose that the accessory genomes of viruses reflect the integrated evolutionary history of the hosts they infected.
Topics: Bacteriophage T4; Bacteriophages; Defense Mechanisms; Escherichia coli; Host Specificity; Toxin-Antitoxin Systems
PubMed: 35924892
DOI: 10.7554/eLife.79549 -
Current Research in Microbial Sciences Dec 2021Numerous harmful microorganisms and insect pests have the ability to cause plant infections or damage, which is mostly controlled by toxic chemical agents. These... (Review)
Review
Numerous harmful microorganisms and insect pests have the ability to cause plant infections or damage, which is mostly controlled by toxic chemical agents. These chemical compounds and their derivatives exhibit hazardous effects on habitats and human life too. Hence, there's a need to develop novel, more effective and safe bio-control agents. A variety of microbes such as viruses, bacteria, and fungi possess a great potential to fight against phytopathogens and thus can be used as bio-control agents instead of harmful chemical compounds. These naturally occurring microorganisms are applied to the plants in order to control phytopathogens. Moreover, practicing them appropriately for agriculture management can be a way towards a sustainable approach. The MBCAs follow various modes of action and act as elicitors where they induce a signal to activate plant defense mechanisms against a variety of pathogens. MBCAs control phytopathogens and help in disease suppression through the production of enzymes, antimicrobial compounds, antagonist activity involving hyper-parasitism, induced resistance, competitive inhibition, etc. Efficient recognition of pathogens and prompt defensive response are key factors of induced resistance in plants. This resistance phenomenon is pertaining to a complex cascade that involves an increased amount of defensive proteins, salicylic acid (SA), or induction of signaling pathways dependent on plant hormones. Although, there's a dearth of information about the exact mechanism of plant-induced resistance, the studies conducted at the physiological, biochemical and genetic levels. These studies tried to explain a series of plant defensive responses triggered by bio-control agents that may enhance the defensive capacity of plants. Several natural and recombinant microorganisms are commercially available as bio-control agents that mainly include strains of and . However, the complete understanding of microbial bio-control agents and their interactions at cellular and molecular levels will facilitate the screening of effective and eco-friendly bio-agents, thereby increasing the scope of MBCAs. This article is a comprehensive review that highlights the importance of microbial agents as elicitors in the activation and regulation of plant defense mechanisms in response to a variety of pathogens.
PubMed: 34841345
DOI: 10.1016/j.crmicr.2021.100054