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The New Phytologist 2009Many biotrophic fungal and oomycete pathogens share a common infection process involving the formation of haustoria, which penetrate host cell walls and form a close... (Review)
Review
Many biotrophic fungal and oomycete pathogens share a common infection process involving the formation of haustoria, which penetrate host cell walls and form a close association with plant membranes. Recent studies have identified a class of pathogenicity effector proteins from these pathogens that is transferred into host cells from haustoria during infection. This insight stemmed from the identification of avirulence (Avr) proteins from these pathogens that are recognized by intracellular host resistance (R) proteins. Oomycete effectors contain a conserved translocation motif that directs their uptake into host cells independently of the pathogen, and is shared with the human malaria pathogen. Genome sequence information indicates that oomycetes may express several hundred such host-translocated effectors. Elucidating the transport mechanism of fungal and oomycete effectors and their roles in disease offers new opportunities to understand how these pathogens are able to manipulate host cells to establish a parasitic relationship and to develop new disease-control measures.
Topics: Algal Proteins; Amino Acid Motifs; Animals; Base Sequence; Biological Transport; Fungal Proteins; Fungi; Genome; Host-Pathogen Interactions; Humans; Oomycetes; Plant Diseases; Plants; Plasmodium falciparum; Translocation, Genetic; Virulence
PubMed: 19558422
DOI: 10.1111/j.1469-8137.2009.02922.x -
Annual Review of Phytopathology Sep 2023Plant bacterial pathogens rely on host-derived signals to coordinate the deployment of virulence factors required for infection. In this review, I describe how diverse... (Review)
Review
Plant bacterial pathogens rely on host-derived signals to coordinate the deployment of virulence factors required for infection. In this review, I describe how diverse plant-pathogenic bacteria detect and respond to plant-derived metabolic signals for the purpose of virulence gene regulation. I highlight examples of how pathogens perceive host metabolites through membrane-localized receptors as well as intracellular response mechanisms. Furthermore, I describe how individual strains may coordinate their virulence using multiple distinct host metabolic signals, and how plant signals may positively or negatively regulate virulence responses. I also describe how plant defenses may interfere with the perception of host metabolites as a means to dampen pathogen virulence. The emerging picture is that recognition of host metabolic signals for the purpose of virulence gene regulation represents an important primary layer of interaction between pathogenic bacteria and host plants that shapes infection outcomes.
Topics: Virulence; Signal Transduction; Plant Diseases; Plants; Bacteria
PubMed: 37253693
DOI: 10.1146/annurev-phyto-021621-114026 -
Memorias Do Instituto Oswaldo Cruz 2018Cryptococcus neoformans is an opportunistic pathogenic yeast that causes serious infections, most commonly of the central nervous system (CNS). C. neoformans is mainly... (Review)
Review
Cryptococcus neoformans is an opportunistic pathogenic yeast that causes serious infections, most commonly of the central nervous system (CNS). C. neoformans is mainly found in the environment and acquired by inhalation. It could be metaphorically imagined that cryptococcal disease is a "journey" for the microorganism that starts in the environment, where this yeast loads its suitcase with virulence traits. C. neoformans first encounters the infected mammalian host in the lungs, a site in which it must choose the right elements from its "virulence suitcase" to survive the pulmonary immune response. However, the lung is often only the first stop in this journey, and in some individuals the fungal trip continues to the brain. To enter the brain, C. neoformans must "open" the main barrier that protects this organ, the blood brain barrier (BBB). Once in the brain, C. neoformans expresses a distinct set of protective attributes that confers a strong neurotropism and the ability to cause brain colonisation. In summary, C. neoformans is a unique fungal pathogen as shown in its ability to survive in the face of multiple stress factors and to express virulence factors that contribute to the development of disease.
Topics: Animals; Blood-Brain Barrier; Central Nervous System Bacterial Infections; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Humans; Virulence
PubMed: 29668825
DOI: 10.1590/0074-02760180057 -
Cellular and Molecular Life Sciences :... May 2003Listeriosis is a severe human and animal disease caused by two species of pathogenic bacteria from the genus Listeria, L. monocytogenes and L. ivanovii. In humans,... (Review)
Review
Listeriosis is a severe human and animal disease caused by two species of pathogenic bacteria from the genus Listeria, L. monocytogenes and L. ivanovii. In humans, listeriosis is overwhelmingly a foodborne disease, yet much remains to be learned regarding the transmission dynamics of pathogenic Listeria from the environment, through food, to humans. Similarly, our understanding of the various host, pathogen and environmental factors that impact the pathogenesis of listeriosis at the cellular and molecular level is incomplete. This review will summarize what is currently known about animal and human listeriosis, detail the pathogen, host and environmental factors that contribute to pathogenesis and, finally, examine the interactions among those factors that influence the occurrence of human infection.
Topics: Animals; Biofilms; Environment; Genetic Predisposition to Disease; Humans; Listeria monocytogenes; Listeriosis; Risk Factors; Virulence
PubMed: 12827280
DOI: 10.1007/s00018-003-2225-6 -
Gut Microbes 2012Much is known about the molecular effectors of pathogenicity of gram-negative enteric pathogens, among which Shigella can be considered a model. This is due to its... (Review)
Review
Much is known about the molecular effectors of pathogenicity of gram-negative enteric pathogens, among which Shigella can be considered a model. This is due to its capacity to recapitulate the multiple steps required for a pathogenic microbe to survive close to its mucosal target, colonize and then invade its epithelial surface, cause its inflammatory destruction and simultaneously regulate the extent of the elicited innate response to likely survive the encounter and achieve successful subsequent transmission. These various steps of the infectious process represent an array of successive environmental conditions to which the bacteria need to successfully adapt. These conditions represent the selective pressure that triggered the "arms race" in which Shigella acquired the genetic and molecular effectors of its pathogenic armory, including the regulatory hierarchies that regulate the expression and function of these effectors. They also represent cues through which Shigella achieves the temporo-spatial expression and regulation of its virulence effectors. The role of such environmental cues has recently become obvious in the case of the major virulence effector of Shigella, the type three secretion system (T3SS) and its dedicated secreted virulence effectors. It needs to be better defined for other major virulence components such as the LPS and peptidoglycan which are used as examples here, in addition to the T3SS as models of regulation as it relates to the assembly and functional regulation of complex macromolecular systems of the bacterial surface. This review also stresses the need to better define what the true and relevant environmental conditions can be at the various steps of the progression of infection. The "identity" of the pathogen differs depending whether it is cultivated under in vitro or in vivo conditions. Moreover, this "identity" may quickly change during its progression into the infected tissue. Novel concepts and relevant tools are needed to address this challenge in microbial pathogenesis.
Topics: Adaptation, Physiological; Bacterial Proteins; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Immunity, Innate; Shigella; Virulence; Virulence Factors
PubMed: 22356862
DOI: 10.4161/gmic.19325 -
International Journal of Molecular... May 2021This review focuses on the molecular chaperone ClpB that belongs to the Hsp100/Clp subfamily of the AAA+ ATPases and its biological function in selected bacterial... (Review)
Review
This review focuses on the molecular chaperone ClpB that belongs to the Hsp100/Clp subfamily of the AAA+ ATPases and its biological function in selected bacterial pathogens, causing a variety of human infectious diseases, including zoonoses. It has been established that ClpB disaggregates and reactivates aggregated cellular proteins. It has been postulated that ClpB's protein disaggregation activity supports the survival of pathogenic bacteria under host-induced stresses (e.g., high temperature and oxidative stress), which allows them to rapidly adapt to the human host and establish infection. Interestingly, ClpB may also perform other functions in pathogenic bacteria, which are required for their virulence. Since ClpB is not found in human cells, this chaperone emerges as an attractive target for novel antimicrobial therapies in combating bacterial infections.
Topics: ATPases Associated with Diverse Cellular Activities; Animals; Bacteria; Bacterial Infections; Bacterial Physiological Phenomena; Bacterial Proteins; Bacterial Zoonoses; Endopeptidase Clp; Heat-Shock Proteins; Host Microbial Interactions; Humans; Models, Molecular; Protein Conformation; Virulence
PubMed: 34070174
DOI: 10.3390/ijms22105319 -
Trends in Microbiology Sep 1997In many pathogens, virulence can be conferred by a single region of the genome. In contrast, the facultative intracellular lifestyle of Salmonella demands a large number... (Review)
Review
In many pathogens, virulence can be conferred by a single region of the genome. In contrast, the facultative intracellular lifestyle of Salmonella demands a large number of genes distributed around the chromosome. The evolution of Salmonella has been marked by the acquisition of several 'pathogenicity islands', each contributing to the unique virulence properties of this microorganism.
Topics: Chromosome Mapping; Gene Expression Regulation, Bacterial; Genes, Bacterial; Gram-Negative Bacteria; Host-Parasite Interactions; Phylogeny; Salmonella; Virulence
PubMed: 9294889
DOI: 10.1016/S0966-842X(97)01099-8 -
Genome Biology 2008Metazoans contain multiple complex microbial ecosystems in which the balance between host and microbe can be tipped from commensalism to pathogenicity. This transition... (Review)
Review
Metazoans contain multiple complex microbial ecosystems in which the balance between host and microbe can be tipped from commensalism to pathogenicity. This transition is likely to depend both on the prevailing environmental conditions and on specific gene-gene interactions placed within the context of the entire ecosystem.
Topics: Animals; Bacteria; Host-Pathogen Interactions; Humans; Mutation; Virulence
PubMed: 18598378
DOI: 10.1186/gb-2008-9-6-225 -
FEMS Microbiology Reviews Jan 2016Modern society and global ecosystems are increasingly under threat from pathogens, which cause a plethora of human, animal, invertebrate and plant diseases. Of... (Review)
Review
Modern society and global ecosystems are increasingly under threat from pathogens, which cause a plethora of human, animal, invertebrate and plant diseases. Of increasing concern is the trans-kingdom tendency for increased pathogen virulence that is beginning to emerge in natural, clinical and agricultural settings. The study of pathogenicity has revealed multiple examples of convergently evolved virulence mechanisms. Originally described as rare, but increasingly common, are interactions where a single gene deletion in a pathogenic species causes hypervirulence. This review utilised the pathogen-host interaction database (www.PHI-base.org) to identify 112 hypervirulent mutations from 37 pathogen species, and subsequently interrogates the trans-kingdom, conserved, molecular, biochemical and cellular themes that cause hypervirulence. This study investigates 22 animal and 15 plant pathogens including 17 bacterial and 17 fungal species. Finally, the evolutionary significance and trans-kingdom requirement for negative regulators of hypervirulence and the implication of pathogen hypervirulence and emerging infectious diseases on society are discussed.
Topics: Animals; Bacteria; Bacterial Infections; Fungi; Host-Pathogen Interactions; Humans; Mutation; Mycoses; Plant Diseases; Plants; Virulence
PubMed: 26468211
DOI: 10.1093/femsre/fuv042 -
PLoS Pathogens Nov 2009