-
Molecular Plant Pathology Jun 2022Extracellular vesicles (EVs) are rounded vesicles enclosed by a lipid bilayer membrane, released by eukaryotic cells and by bacteria. They carry various types of... (Review)
Review
Extracellular vesicles (EVs) are rounded vesicles enclosed by a lipid bilayer membrane, released by eukaryotic cells and by bacteria. They carry various types of bioactive substances, including nucleic acids, proteins, and lipids. Depending on their cargo, EVs have a variety of well-studied functions in mammalian systems, including cell-to-cell communication, cancer progression, and pathogenesis. In contrast, EVs in plant cells (which have rigid walls) have received very little research attention for many decades. Increasing evidence during the past decade indicates that both plant cells and plant pathogens are able to produce and secrete EVs, and that such EVs play key roles in plant-pathogen interactions. Plant EVs contains small RNAs (sRNAs) and defence-related proteins, and may be taken up by pathogenic fungi, resulting in reduced virulence. On the other hand, EVs released by gram-negative bacteria contain a wide variety of effectors and small molecules capable of activating plant immune responses via pattern-recognition receptor- and BRI1-ASSOCIATED RECEPTOR KINASE- and SUPPRESSOR OF BIR1-mediated signalling pathways, and salicylic acid-dependent and -independent processes. The roles of EVs in plant-pathogen interactions are summarized in this review, with emphasis on important molecules (sRNAs, proteins) present in plant EVs.
Topics: Animals; Extracellular Vesicles; Fungi; Mammals; Plants; Signal Transduction; Virulence
PubMed: 34873812
DOI: 10.1111/mpp.13170 -
Molecular Genetics and Genomics : MGG Nov 2022The current pandemic (COVID-19) has made evident the need to approach pathogenicity from a deeper and more systematic perspective that might lead to methodologies to...
The current pandemic (COVID-19) has made evident the need to approach pathogenicity from a deeper and more systematic perspective that might lead to methodologies to quickly predict new strains of microbes that could be pathogenic to humans. Here we propose as a solution a general and principled definition of pathogenicity that can be practically implemented in operational ways in a framework for characterizing and assessing the (degree of) potential pathogenicity of a microbe to a given host (e.g., a human individual) just based on DNA biomarkers, and to the point of predicting its impact on a host a priori to a meaningful degree of accuracy. The definition is based on basic biochemistry, the Gibbs free Energy of duplex formation between oligonucleotides and some deep structural properties of DNA revealed by an approximation with certain properties. We propose two operational tests based on the nearest neighbor (NN) model of the Gibbs Energy and an approximating metric (the h-distance.) Quality assessments demonstrate that these tests predict pathogenicity with an accuracy of over 80%, and sensitivity and specificity over 90%. Other tests obtained by training machine learning models on deep features extracted from DNA sequences yield scores of 90% for accuracy, 100% for sensitivity and 80% for specificity. These results hint towards the possibility of an operational, objective, and general conceptual framework for prior identification of pathogens and their impact without the cost of death or sickness in a host (e.g., humans.) Consequently, a reasonable prediction of possible pathogens might pave the way to eventually transform the way we handle and prepare for future pandemic events and mitigate the adverse impact on human health, while reducing the number of clinical trials to obtain similar results.
Topics: Humans; Virulence; COVID-19; Oligonucleotides; DNA; Biomarkers
PubMed: 36125534
DOI: 10.1007/s00438-022-01951-w -
PeerJ 2022Obligate fungal pathogens (ascomycetes and basidiomycetes) and oomycetes are known to cause diseases in cereal crop plants. They feed on living cells and most of them... (Review)
Review
Obligate fungal pathogens (ascomycetes and basidiomycetes) and oomycetes are known to cause diseases in cereal crop plants. They feed on living cells and most of them have learned to bypass the host immune machinery. This paper discusses some of the factors that are associated with pathogenicity drawing examples from ascomycetes, basidiomycetes and oomycetes, with respect to their manifestation in crop plants. The comparisons have revealed a striking similarity in the three groups suggesting convergent pathways that have arisen from three lineages independently leading to an obligate lifestyle. This review has been written with the intent, that new information on adaptation strategies of biotrophs, modifications in pathogenicity strategies and population dynamics will improve current strategies for breeding with stable resistance.
Topics: Virulence; Plant Breeding; Oomycetes; Adaptation, Physiological; Ascomycota
PubMed: 36042858
DOI: 10.7717/peerj.13794 -
Frontiers in Cellular and Infection... 2023For several decades, questions have been raised about the effects of endocrine disruptors (ED) on environment and health. In humans, EDs interferes with hormones that... (Review)
Review
For several decades, questions have been raised about the effects of endocrine disruptors (ED) on environment and health. In humans, EDs interferes with hormones that are responsible for the maintenance of homeostasis, reproduction and development and therefore can cause developmental, metabolic and reproductive disorders. Because of their ubiquity in the environment, EDs can adversely impact microbial communities and pathogens virulence. At a time when bacterial resistance is inevitably emerging, it is necessary to understand the effects of EDs on the behavior of pathogenic bacteria and to identify the resulting mechanisms. Increasing studies have shown that exposure to environmental EDs can affect bacteria physiology. This review aims to highlight current knowledge of the effect of EDs on the virulence of human bacterial pathogens and discuss the future directions to investigate bacteria/EDs interaction. Given the data presented here, extended studies are required to understand the mechanisms by which EDs could modulate bacterial phenotypes in order to understand the health risks.
Topics: Humans; Endocrine Disruptors; Virulence; Hormones; Homeostasis; Phenotype
PubMed: 38029256
DOI: 10.3389/fcimb.2023.1292233 -
Virulence Dec 2022, a pathogen from class Mollicutes, has been linked to sexually transmitted diseases and sparked widespread concern. To adapt to its environment, has evolved specific... (Review)
Review
, a pathogen from class Mollicutes, has been linked to sexually transmitted diseases and sparked widespread concern. To adapt to its environment, has evolved specific adhesins and motility mechanisms that allow it to adhere to and invade various eukaryotic cells, thereby causing severe damage to the cells. Even though traditional exotoxins have not been identified, secreted nucleases or membrane lipoproteins have been shown to cause cell death and inflammatory injury in infection. However, as both innate and adaptive immune responses are important for controlling infection, the immune responses that develop upon infection do not necessarily eliminate the organism completely. Antigenic variation, detoxifying enzymes, immunoglobulins, neutrophil extracellular trap-degrading enzymes, cell invasion, and biofilm formation are important factors that help the pathogen overcome the host defence and cause chronic infections in susceptible individuals. Furthermore, can increase the susceptibility to several sexually transmitted pathogens, which significantly complicates the persistence and chronicity of infection. This review aimed to discuss the virulence factors of to shed light on its complex pathogenicity and pathogenesis of the infection.
Topics: Adhesins, Bacterial; Humans; Mycoplasma Infections; Mycoplasma genitalium; Virulence; Virulence Factors
PubMed: 35791283
DOI: 10.1080/21505594.2022.2095741 -
Phytopathology Apr 2023Effectors play a central role in determining the outcome of plant-pathogen interactions. As key virulence proteins, effectors are collectively indispensable for disease... (Review)
Review
Effectors play a central role in determining the outcome of plant-pathogen interactions. As key virulence proteins, effectors are collectively indispensable for disease development. By understanding the virulence mechanisms of effectors, fundamental knowledge of microbial pathogenesis and disease resistance have been revealed. Effectors are also considered double-edged swords because some of them activate immunity in disease resistant plants after being recognized by specific immune receptors, which evolved to monitor pathogen presence or activity. Characterization of effector recognition by their cognate immune receptors and the downstream immune signaling pathways is instrumental in implementing resistance. Over the past decades, substantial research effort has focused on effector biology, especially concerning their interactions with virulence targets or immune receptors in plant cells. A foundation of this research is robust identification of the effector repertoire from a given pathogen, which depends heavily on bioinformatic prediction. In this review, we summarize methodologies that have been used for effector mining in various microbial pathogens which use different effector delivery mechanisms. We also discuss current limitations and provide perspectives on how recently developed analytic tools and technologies may facilitate effector identification and hence generation of a more complete vision of host-pathogen interactions. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Topics: Plant Diseases; Plants; Disease Resistance; Plant Proteins; Virulence; Plant Immunity
PubMed: 37126080
DOI: 10.1094/PHYTO-09-22-0337-KD -
Molecular Cell May 2020Commensal microbial communities inhabit biological niches in the mammalian host, where they impact the host's physiology through induction of "colonization resistance"... (Review)
Review
Commensal microbial communities inhabit biological niches in the mammalian host, where they impact the host's physiology through induction of "colonization resistance" against infections by a multitude of molecular mechanisms. These colonization-regulating activities involve microbe-microbe and microbe-host interactions, which induce, through utilization of complex bacterial networks, competition over nutrients, inhibition by antimicrobial peptides, stimulation of the host immune system, and promotion of mucus and intestinal epithelial barrier integrity. Distinct virulent pathogens overcome this colonization resistance and host immunity as part of a hostile takeover of the host niche, leading to clinically overt infection. The following review provides a mechanistic overview of the role of commensal microbes in modulating colonization resistance and pathogenic infections and means by which infectious agents may overcome such inhibition. Last, we outline evidence, unknowns, and challenges in developing strategies to harness this knowledge to treat infections by microbiota transfer, phage therapy, or supplementation by rationally defined bacterial consortia.
Topics: Anti-Bacterial Agents; Bacteria; Drug Resistance, Microbial; Host-Pathogen Interactions; Humans; Infections; Microbiota; Virulence
PubMed: 32208169
DOI: 10.1016/j.molcel.2020.03.001 -
Frontiers in Cellular and Infection... 2019During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of... (Review)
Review
During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of adaptation requires a robust modulation of their physiological and metabolic features. Additionally, virulence determinants, which include host invasion, colonization and survival despite the host's immune responses and antimicrobial therapy, must be optimally orchestrated by the pathogen at all times during infection. This can only be achieved by tight coordination of gene expression. A large body of evidence implicate the prolific roles played by bacterial regulatory RNAs in mediating gene expression both at the transcriptional and post-transcriptional levels. This review describes mechanistic and regulatory aspects of bacterial regulatory RNAs and highlights how these molecules increase virulence efficiency in human pathogens. As illustrative examples, , the uropathogenic strain of , and have been selected.
Topics: Animals; Bacterial Infections; Bacterial Physiological Phenomena; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; RNA, Bacterial; Species Specificity; Virulence; Virulence Factors
PubMed: 31649894
DOI: 10.3389/fcimb.2019.00337 -
Nature Microbiology Jan 2020Microbial pathogens possess an arsenal of strategies to invade their hosts, evade immune defences and promote infection. In particular, bacteria use virulence factors,... (Review)
Review
Microbial pathogens possess an arsenal of strategies to invade their hosts, evade immune defences and promote infection. In particular, bacteria use virulence factors, such as secreted toxins and effector proteins, to manipulate host cellular processes and establish a replicative niche. Survival of eukaryotic organisms in the face of such challenge requires host mechanisms to detect and counteract these pathogen-specific virulence strategies. In this Review, we focus on effector-triggered immunity (ETI) in metazoan organisms as a mechanism for pathogen sensing and distinguishing pathogenic from non-pathogenic microorganisms. For the purposes of this Review, we adopt the concept of ETI formulated originally in the context of plant pathogens and their hosts, wherein specific host proteins 'guard' central cellular processes and trigger inflammatory responses following pathogen-driven disruption of these processes. While molecular mechanisms of ETI are well-described in plants, our understanding of functionally analogous mechanisms in metazoans is still emerging. In this Review, we present an overview of ETI in metazoans and discuss recently described cellular processes that are guarded by the host. Although all pathogens manipulate host pathways, we focus primarily on bacterial pathogens and highlight pathways of effector-triggered immune defence that sense disruption of core cellular processes by pathogens. Finally, we discuss recent developments in our understanding of how pathogens can evade ETI to overcome these host adaptations.
Topics: Animals; Bacteria; Bacterial Infections; Immune Evasion; Immunity, Innate; Inflammasomes; Receptors, Pattern Recognition; Signal Transduction; Virulence; Virulence Factors
PubMed: 31857733
DOI: 10.1038/s41564-019-0623-2 -
Frontiers in Bioscience (Landmark... Mar 2020Infectious diseases caused by numerous parasitic pathogens represent a global health conundrum. Several animal and plant pathogens are responsible for causing acute... (Review)
Review
Infectious diseases caused by numerous parasitic pathogens represent a global health conundrum. Several animal and plant pathogens are responsible for causing acute illness in humans and deadly plant infections. These pathogens have evolved a diverse array of infection strategies and survival methods within the host organism. Recent research has highlighted the role of protein kinases in the overall virulence and pathogenicity of the pathogens. Protein kinases (Pks) are a group of enzymes known to catalyse the phosphorylation of a wide variety of cellular substrates involved in different signalling cascades. They are also involved in regulating pathogen life cycle and infectivity. In this review, we attempt to address the role of parasite kinome in host infection, pathogen survival within the host tissue and thereby disease manifestation. The understanding of the parasite kinome can be a potential target for robust diagnosis and effective therapeutics.
Topics: Animals; Bacteria; Fungi; Host-Pathogen Interactions; Humans; Nematoda; Phosphorylation; Plant Diseases; Plasmodium; Protein Kinases; Virulence
PubMed: 32114442
DOI: 10.2741/4865