The Experts below are selected from a list of 13299 Experts worldwide ranked by ideXlab platform

Liise Anne Pirofski - One of the best experts on this subject based on the ideXlab platform.

  • The state of latency in Microbial Pathogenesis.
    The Journal of clinical investigation, 2020
    Co-Authors: Liise Anne Pirofski, Arturo Casadevall
    Abstract:

    The state of latency occurs when a microbe's persistence in a host produces host damage without perturbing homeostasis sufficiently to cause clinical symptoms or disease. The mechanisms contributing to latency are diverse and depend on the nature of both the microbe and the host. Latency has advantages for both host and microbe. The host avoids progressive damage caused by interaction with the microbe that may translate into disease, and the microbe secures a stable niche in which to survive. Latency is clinically important because some latent microbes can be transmitted to other hosts, and it is associated with a risk for recrudescent Microbial growth and development of disease. In addition, it can predispose the host to other diseases, such as malignancies. Hence, latency is a temporally unstable state with an eventual outcome that mainly depends on host immunity. Latency is an integral part of the pathogenic strategies of microbes that require human (and/or mammalian) hosts, including herpesviruses, retroviruses, Mycobacterium tuberculosis, and Toxoplasma gondii. However, latency is also an outcome of infection with environmental organisms such as Cryptococcus neoformans, which require no host in their replicative cycles. For most microbes that achieve latency, there is a need for a better understanding and more investigation of host and Microbial mechanisms that result in this state.

  • What Is a Host? Incorporating the Microbiota into the Damage-Response Framework
    Infection and immunity, 2014
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    Since proof of the germ theory of disease in the late 19th century, a major focus of the fields of microbiology and infectious diseases has been to seek differences between pathogenic and nonpathogenic microbes and the role that the host plays in Microbial Pathogenesis. Remarkably, despite the increasing recognition that host immunity plays a role in Microbial Pathogenesis, there has been little discussion about what constitutes a host. Historically, hosts have been viewed in the context of their fitness or immunological status and characterized by adjectives such as immune, immunocompetent, immunosuppressed, immunocompromised, or immunologically impaired. However, in recent years it has become apparent that the microbiota has profound effects on host homeostasis and susceptibility to Microbial diseases in addition to its effects on host immunity. This raises the question of how to incorporate the microbiota into defining a host. This definitional problem is further complicated because neither host nor Microbial properties are adequate to predict the outcome of host-microbe interaction because this outcome exhibits emergent properties. In this essay, we revisit the damage-response framework (DRF) of Microbial Pathogenesis and demonstrate how it can incorporate the rapidly accumulating information being generated by the microbiome revolution. We use the tenets of the DRF to put forth the following definition of a host: a host is an entity that houses an associated microbiome/microbiota and interacts with microbes such that the outcome results in damage, benefit, or indifference, thus resulting in the states of symbiosis, colonization, commensalism, latency, and disease.

  • Virulence factors and their mechanisms of action: the view from a damage–response framework
    Journal of Water and Health, 2009
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    The virulence factor concept has been a powerful engine in driving research and the intellectual flow in the fields of Microbial Pathogenesis and infectious diseases. This review analyzes virulence factors from the viewpoint of the damage-response framework of Microbial Pathogenesis, which defines virulence factor as Microbial components that can damage a susceptible host. At a practical level, the finding that effective immune responses often target virulence factors provides a roadmap for future vaccine design. However, there are significant limitations to this concept, which are rooted in the inability to define virulence and virulence factors in the absence of host factors and the host response. In fact, this concept appears to work best for certain types of bacterial pathogens, being less well suited for viruses and commensal organisms with pathogenic potential.

  • Virulence factors and their mechanisms of action: the view from a damage-response framework.
    Journal of water and health, 2009
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    The virulence factor concept has been a powerful engine in driving research and the intellectual flow in the fields of Microbial Pathogenesis and infectious diseases. This review analyzes virulence factors from the viewpoint of the damage-response framework of Microbial Pathogenesis, which defines virulence factor as Microbial components that can damage a susceptible host. At a practical level, the finding that effective immune responses often target virulence factors provides a roadmap for future vaccine design. However, there are significant limitations to this concept, which are rooted in the inability to define virulence and virulence factors in the absence of host factors and the host response. In fact, this concept appears to work best for certain types of bacterial pathogens, being less well suited for viruses and commensal organisms with pathogenic potential.

  • The Damage-Response Framework of Microbial Pathogenesis and Infectious Diseases
    Advances in experimental medicine and biology, 2008
    Co-Authors: Liise Anne Pirofski, Arturo Casadevall
    Abstract:

    Historical and most currently held views of Microbial Pathogenesis and virulence are plagued by confusing and imprecise terminology and definitions that require revision and exceptions to accommodate new basic science and clinical information about microbes and infectious diseases. These views are also inherently unable to account for the ability of some microbes to cause disease in certain, but not other hosts, because they are grounded in singular, either microbe-or host-centric views. The damage-response framework is an integrated theory of Microbial Pathogenesis that puts forth the view that Microbial Pathogenesis reflects the outcome of an interaction between a host and a microbe, with each entiry contributing to the nature of the outcome, which in turn depends on the amount of host damage that results from the host-microbe interaction. This view is able to accommodate new information and explain why infection with the same microbe can have different outcomes in different hosts. This chapter describes the origins and conceptual underpinnings of and the outcomes of infection put forth in, the damage-response framework.

Arturo Casadevall - One of the best experts on this subject based on the ideXlab platform.

  • The state of latency in Microbial Pathogenesis.
    The Journal of clinical investigation, 2020
    Co-Authors: Liise Anne Pirofski, Arturo Casadevall
    Abstract:

    The state of latency occurs when a microbe's persistence in a host produces host damage without perturbing homeostasis sufficiently to cause clinical symptoms or disease. The mechanisms contributing to latency are diverse and depend on the nature of both the microbe and the host. Latency has advantages for both host and microbe. The host avoids progressive damage caused by interaction with the microbe that may translate into disease, and the microbe secures a stable niche in which to survive. Latency is clinically important because some latent microbes can be transmitted to other hosts, and it is associated with a risk for recrudescent Microbial growth and development of disease. In addition, it can predispose the host to other diseases, such as malignancies. Hence, latency is a temporally unstable state with an eventual outcome that mainly depends on host immunity. Latency is an integral part of the pathogenic strategies of microbes that require human (and/or mammalian) hosts, including herpesviruses, retroviruses, Mycobacterium tuberculosis, and Toxoplasma gondii. However, latency is also an outcome of infection with environmental organisms such as Cryptococcus neoformans, which require no host in their replicative cycles. For most microbes that achieve latency, there is a need for a better understanding and more investigation of host and Microbial mechanisms that result in this state.

  • What Is a Host? Incorporating the Microbiota into the Damage-Response Framework
    Infection and immunity, 2014
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    Since proof of the germ theory of disease in the late 19th century, a major focus of the fields of microbiology and infectious diseases has been to seek differences between pathogenic and nonpathogenic microbes and the role that the host plays in Microbial Pathogenesis. Remarkably, despite the increasing recognition that host immunity plays a role in Microbial Pathogenesis, there has been little discussion about what constitutes a host. Historically, hosts have been viewed in the context of their fitness or immunological status and characterized by adjectives such as immune, immunocompetent, immunosuppressed, immunocompromised, or immunologically impaired. However, in recent years it has become apparent that the microbiota has profound effects on host homeostasis and susceptibility to Microbial diseases in addition to its effects on host immunity. This raises the question of how to incorporate the microbiota into defining a host. This definitional problem is further complicated because neither host nor Microbial properties are adequate to predict the outcome of host-microbe interaction because this outcome exhibits emergent properties. In this essay, we revisit the damage-response framework (DRF) of Microbial Pathogenesis and demonstrate how it can incorporate the rapidly accumulating information being generated by the microbiome revolution. We use the tenets of the DRF to put forth the following definition of a host: a host is an entity that houses an associated microbiome/microbiota and interacts with microbes such that the outcome results in damage, benefit, or indifference, thus resulting in the states of symbiosis, colonization, commensalism, latency, and disease.

  • Virulence factors and their mechanisms of action: the view from a damage–response framework
    Journal of Water and Health, 2009
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    The virulence factor concept has been a powerful engine in driving research and the intellectual flow in the fields of Microbial Pathogenesis and infectious diseases. This review analyzes virulence factors from the viewpoint of the damage-response framework of Microbial Pathogenesis, which defines virulence factor as Microbial components that can damage a susceptible host. At a practical level, the finding that effective immune responses often target virulence factors provides a roadmap for future vaccine design. However, there are significant limitations to this concept, which are rooted in the inability to define virulence and virulence factors in the absence of host factors and the host response. In fact, this concept appears to work best for certain types of bacterial pathogens, being less well suited for viruses and commensal organisms with pathogenic potential.

  • Virulence factors and their mechanisms of action: the view from a damage-response framework.
    Journal of water and health, 2009
    Co-Authors: Arturo Casadevall, Liise Anne Pirofski
    Abstract:

    The virulence factor concept has been a powerful engine in driving research and the intellectual flow in the fields of Microbial Pathogenesis and infectious diseases. This review analyzes virulence factors from the viewpoint of the damage-response framework of Microbial Pathogenesis, which defines virulence factor as Microbial components that can damage a susceptible host. At a practical level, the finding that effective immune responses often target virulence factors provides a roadmap for future vaccine design. However, there are significant limitations to this concept, which are rooted in the inability to define virulence and virulence factors in the absence of host factors and the host response. In fact, this concept appears to work best for certain types of bacterial pathogens, being less well suited for viruses and commensal organisms with pathogenic potential.

  • The Damage-Response Framework of Microbial Pathogenesis and Infectious Diseases
    Advances in experimental medicine and biology, 2008
    Co-Authors: Liise Anne Pirofski, Arturo Casadevall
    Abstract:

    Historical and most currently held views of Microbial Pathogenesis and virulence are plagued by confusing and imprecise terminology and definitions that require revision and exceptions to accommodate new basic science and clinical information about microbes and infectious diseases. These views are also inherently unable to account for the ability of some microbes to cause disease in certain, but not other hosts, because they are grounded in singular, either microbe-or host-centric views. The damage-response framework is an integrated theory of Microbial Pathogenesis that puts forth the view that Microbial Pathogenesis reflects the outcome of an interaction between a host and a microbe, with each entiry contributing to the nature of the outcome, which in turn depends on the amount of host damage that results from the host-microbe interaction. This view is able to accommodate new information and explain why infection with the same microbe can have different outcomes in different hosts. This chapter describes the origins and conceptual underpinnings of and the outcomes of infection put forth in, the damage-response framework.

Werner Goebel - One of the best experts on this subject based on the ideXlab platform.

  • From the beginning to the present state of molecular Microbial Pathogenesis—A tribute to Pascale Cossart
    Molecular microbiology, 2020
    Co-Authors: Werner Goebel
    Abstract:

    The universe of Molecular Microbial Pathogenesis is filled with many female and male stars. But there are two particularly bright shining supernovae-like stars: the late Stanley Falkow and the very lively and creative Pascale Cossart. These two outstanding luminaries, surrounded by numerous planets, do not only belong to different scientific generations but their splendor also comes from very different scientific concepts. Stanley Falkow, often referred to as the 'Father of Molecular Microbial Pathogenesis', made many groundbreaking contributions to this field by addressing almost all important bacterial pathogens. Pascale Cossart, who could be called in analogy the 'Queen of Modern Molecular Microbial Pathogenesis' by combining the Microbiology and Cell Biology, concentrates in her similarly impressive scientific work essentially on a single bacterial species which she studied and still studies in great depth: the facultative intracellular bacterial pathogen Listeria monocytogenes-and the vast majority of her most prominent publications deals with this pathogen in almost all facets. It is certainly not an exaggeration to say that she together with her co-workers and collaborators developed this model bacterium into a paradigm among the intracellular bacterial pathogens.

  • from the beginning to the present state of molecular Microbial Pathogenesis a tribute to pascale cossart
    Molecular Microbiology, 2020
    Co-Authors: Werner Goebel
    Abstract:

    The universe of Molecular Microbial Pathogenesis is filled with many female and male stars. But there are two particularly bright shining supernovae-like stars: the late Stanley Falkow and the very lively and creative Pascale Cossart. These two outstanding luminaries, surrounded by numerous planets, do not only belong to different scientific generations but their splendor also comes from very different scientific concepts. Stanley Falkow, often referred to as the 'Father of Molecular Microbial Pathogenesis', made many groundbreaking contributions to this field by addressing almost all important bacterial pathogens. Pascale Cossart, who could be called in analogy the 'Queen of Modern Molecular Microbial Pathogenesis' by combining the Microbiology and Cell Biology, concentrates in her similarly impressive scientific work essentially on a single bacterial species which she studied and still studies in great depth: the facultative intracellular bacterial pathogen Listeria monocytogenes-and the vast majority of her most prominent publications deals with this pathogen in almost all facets. It is certainly not an exaggeration to say that she together with her co-workers and collaborators developed this model bacterium into a paradigm among the intracellular bacterial pathogens.

Jorge H. Leitão - One of the best experts on this subject based on the ideXlab platform.

Takaaki Akaike - One of the best experts on this subject based on the ideXlab platform.

  • nitrative stress through formation of 8 nitroguanosine insights into Microbial Pathogenesis
    Nitric Oxide, 2006
    Co-Authors: Teruo Akuta, Mohammad Hasan Zaki, Tatsuya Okamoto, Jun Yoshitake, Takaaki Akaike
    Abstract:

    Reactive oxygen and nitrogen species, respectively, mediate oxidative and nitrative stresses by means of oxidation and nitration of various biomolecules including proteins, lipids, and nucleic acids. We have observed nitric oxide (NO)-dependent formation of 8-nitroguanosine and 3-nitrotyrosine during Microbial infection, and we determined that both 8-nitroguanosine and 3-nitrotyrosine are useful biomarkers of nitrative stress. Of importance, however, is the great difference in biological characteristics of these two nitrated compounds. 8-Nitroguanosine has unique biochemical and pharmacological properties such as redox activity and mutagenic potential, which 3-nitrotyrosine does not. In this review, we discuss the mechanism of nitrative stress occurring during Microbial infections, with special emphasis on biological functions of 8-nitroguanosine formed via NO during the host response to pathogens. These findings provide insights into NO-mediated Pathogenesis not only of viral infections but also of many other diseases.

  • nitric oxide induced nitrative stress involved in Microbial Pathogenesis
    Journal of Pharmacological Sciences, 2005
    Co-Authors: Mohammad Hasan Zaki, Teruo Akuta, Takaaki Akaike
    Abstract:

    Abstract The pathogenic mechanism of infections is a complicated but important scientific theme that is now attracting great attention because of its association with host-derived as well as Microbial factors. Recent advances in free radical research revealed that reactive oxygen and nitrogen oxide species such as superoxide (O2−) and nitric oxide (NO) play a leading role in the Pathogenesis of infections caused by viral pathogens including influenza virus and other RNA viruses. Although NO and O2− have antiMicrobial activity against bacteria, fungi, and parasites, in some viral infections they have an opposite effect. This exacerbation caused by NO and O2− is mediated by reactive nitrogen oxides, for example, peroxynitrite (ONOO−), generated by reaction of NO with O2−. These nitrogen oxides have strong oxidation and nitration potential and can modify biological molecules, thereby creating oxidative and nitrative stress that contributes to pathogenic processes during viral infection. Nitrative stress-mediated 8-nitroguanosine formation during influenza or Sendai virus infection has been the focus of enormous interest because it involves unique biochemical and pharmacological properties such as redox activity and mutagenic potential. In this review, we discuss the nature and impact of nitrative stress in viral infection, with emphasis on nitrative stress-mediated viral Pathogenesis, which we have recently been investigating.