scholarly journals Disentangling the influence of parasite genotype, host genotype and maternal environment on different stages of bacterial infection in Daphnia magna

2012 ◽  
Vol 279 (1741) ◽  
pp. 3176-3183 ◽  
Author(s):  
Matthew D. Hall ◽  
Dieter Ebert
Keyword(s):  
Infectious Disease ◽  
Daphnia Magna ◽  
Parasite Clearance ◽  
Infection Process ◽  
Host Immune System ◽  
Parasite Genotype ◽  
Host Genotype ◽  
Maternal Environment ◽  
Host Infection ◽  
Host Parasite

Individuals naturally vary in the severity of infectious disease when exposed to a parasite. Dissecting this variation into genetic and environmental components can reveal whether or not this variation depends on the host genotype, parasite genotype or a range of environmental conditions. Complicating this task, however, is that the symptoms of disease result from the combined effect of a series of events, from the initial encounter between a host and parasite, through to the activation of the host immune system and the exploitation of host resources. Here, we use the crustacean Daphnia magna and its parasite Pasteuria ramosa to show how disentangling genetic and environmental factors at different stages of infection improves our understanding of the processes shaping infectious disease. Using compatible host–parasite combinations, we experimentally exclude variation in the ability of a parasite to penetrate the host, from measures of parasite clearance, the reduction in host fecundity and the proliferation of the parasite. We show how parasite resistance consists of two components that vary in environmental sensitivity, how the maternal environment influences all measured aspects of the within-host infection process and how host–parasite interactions following the penetration of the parasite into the host have a distinct temporal component.

scholarly journals The infection rate of Daphnia magna by Pasteuria ramosa conforms with the mass-action principle

2003 ◽  
Vol 131 (2) ◽  
pp. 957-966 ◽  
Author(s):  
R. R. REGOES ◽  
J. W. HOTTINGER ◽  
L. SYGNARSKI ◽  
D. EBERT
Keyword(s):  
Daphnia Magna ◽  
Infection Rate ◽  
Infection Process ◽  
Action Principle ◽  
Mass Action ◽  
Infection Model ◽  
Susceptibility To Infection ◽  
Pasteuria Ramosa ◽  
Simple Mass ◽  
Host Parasite

In simple epidemiological models that describe the interaction between hosts with their parasites, the infection process is commonly assumed to be governed by the law of mass action, i.e. it is assumed that the infection rate depends linearly on the densities of the host and the parasite. The mass-action assumption, however, can be problematic if certain aspects of the host–parasite interaction are very pronounced, such as spatial compartmentalization, host immunity which may protect from infection with low doses, or host heterogeneity with regard to susceptibility to infection. As deviations from a mass-action infection rate have consequences for the dynamics of the host–parasite system, it is important to test for the appropriateness of the mass-action assumption in a given host–parasite system. In this paper, we examine the relationship between the infection rate and the parasite inoculum for the water flee Daphnia magna and its bacterial parasite Pasteuria ramosa. We measured the fraction of infected hosts after exposure to 14 different doses of the parasite. We find that the observed relationship between the fraction of infected hosts and the parasite dose is largely consistent with an infection process governed by the mass-action principle. However, we have evidence for a subtle but significant deviation from a simple mass-action infection model, which can be explained either by some antagonistic effects of the parasite spores during the infection process, or by heterogeneity in the hosts' susceptibility with regard to infection.

Mathematical models of parasite responses to host immune defences

Parasitology ◽  
1997 ◽  
Vol 115 (7) ◽  
pp. 155-167 ◽  
Author(s):  
R. ANTIA ◽  
M. LIPSITCH
Keyword(s):  
Immune System ◽  
Simple Model ◽  
Acute Infection ◽  
Multiple Infections ◽  
Host Immune System ◽  
Host Genotype ◽  
Immune Mediated ◽  
Host Parasite ◽  
Immune Defences ◽  
Rates Of Growth

We examine the evolution of microparasites in response to the immune system of vertebrate hosts. We first describe a simple model for an acute infection. This model suggests that the within-host dynamics of the microparasite will be a ‘race’ between parasite multiplication and a clonally expanding response by the host immune system, resulting either in immune-mediated clearance or host death. In this very simple model, in which there is only a single parasite and host genotype, maximum transmission is obtained by parasites with intermediate rates of growth (and virulence). We examine how these predictions depend on key assumptions about the parasite and the host, and consider how this model may be expanded to incorporate the effect of additional complexities such as host–parasite co-evolution, host polymorphism, and multiple infections.

scholarly journals Temperature effects on parasite prevalence in a natural hybrid complex

2010 ◽  
Vol 7 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Corine N. Schoebel ◽  
Christoph Tellenbach ◽  
Piet Spaak ◽  
Justyna Wolinska
Keyword(s):  
Protozoan Parasite ◽  
Parasite Prevalence ◽  
Host Susceptibility ◽  
Host Genotype ◽  
Genotype By Environment ◽  
Hybrid Complex ◽  
Influence Of Temperature On ◽  
Temperature Interaction ◽  
Host Parasite ◽  
Genetic Specificity

Both host susceptibility and parasite infectivity commonly have a genetic basis, and can therefore be shaped by coevolution. However, these traits are often sensitive to environmental variation, resulting in genotype-by-environment interactions. We tested the influence of temperature on host–parasite genetic specificity in the Daphnia longispina hybrid complex, exposed to the protozoan parasite Caullerya mesnili . Infection rates were higher at low temperature. Furthermore, significant differences between host clones, but not between host taxa, and a host genotype-by-temperature interaction were observed.

scholarly journals Stable Fluorescent and Enzymatic Tagging of Bradyrhizobium diazoefficiens to Analyze Host-Plant Infection and Colonization

2015 ◽  
Vol 28 (9) ◽  
pp. 959-967 ◽  
Author(s):  
Raphael Ledermann ◽  
Ilka Bartsch ◽  
Mitja N. Remus-Emsermann ◽  
Julia A. Vorholt ◽  
Hans-Martin Fischer
Keyword(s):  
Fluorescent Proteins ◽  
Root Nodules ◽  
Microscopic Analysis ◽  
Single Copy ◽  
Infection Process ◽  
Model Systems ◽  
Nodule Occupancy ◽  
Developmental Program ◽  
Plant Infection ◽  
Host Infection

Bradyrhizobium diazoefficiens USDA 110 (formerly named Bradyrhizobium japonicum) can fix dinitrogen when living as an endosymbiont in root nodules of soybean and some other legumes. Formation of a functional symbiosis relies on a defined developmental program mediated by controlled gene expression in both symbiotic partners. In contrast to other well-studied Rhizobium-legume model systems that have been thoroughly examined by means of genetically tagged strains, analysis of B. diazoefficiens host infection has been impaired due to the lack of suitable tagging systems. Here, we describe the construction of B. diazoefficiens strains constitutively expressing single-copy genes for fluorescent proteins (eBFP2, mTurquoise2, GFP+, sYFP2, mCherry, HcRed) and enzymes (GusA, LacZ). For stable inheritance, the constructs were recombined into the chromosome. Effectiveness and versatility of the tagged strains was demonstrated in plant infection assays. (i) The infection process was followed from root-hair attachment to colonization of nodule cells with epifluorescent microscopy. (ii) Monitoring mixed infections with two strains producing different fluorescent proteins allowed rapid analysis of nodule occupancy and revealed that the majority of nodules contained clonal populations. (iii) Microscopic analysis of nodules induced by fluorescent strains provided evidence for host-dependent control of B. diazoefficiens bacteroid morphology in nodules of Aeschynomene afraspera and Arachis hypogaea (peanut), as deduced from their altered morphology compared with bacteroids in soybean nodules.

scholarly journals The impact of resource provisioning on the epidemiological responses of different parasites

2021 ◽  
Author(s):  
Diana Erazo ◽  
Amy B Pedersen ◽  
Andy Fenton
Keyword(s):  
Infectious Diseases ◽  
Anthropogenic Activities ◽  
Resource Provisioning ◽  
Transmission Mode ◽  
Host Susceptibility ◽  
Host Immune System ◽  
Trade Offs ◽  
Duration Of Infection ◽  
Host Parasite ◽  
The Impact

Events such as anthropogenic activities and periodic tree masting can alter resource provisioning in the environment, directly affecting animals, and potentially impacting the spread of infectious diseases in wildlife. The effect of these supplemental resources on infectious diseases can manifest through different pathways, affecting host susceptibility, transmission and host demography. To date however, empirical research has tended to examine these different pathways in isolation, for example by quantifying the effects of provisioning on host behaviour in the wild or changes in immune responses in controlled laboratory studies. Further, while theory has investigated the interactions between these pathways, thus far this work has focussed on a narrow subset of pathogen types, typically directly-transmitted microparasites. Given the diverse ways that provisioning can affect host susceptibility, contact patterns or host demography, we may expect the epidemiological consequences of provisioning to depend on key aspects of parasite life-history, such as the duration of infection and transmission mode. We developed a suite of generic epidemiological models to compare how resource provisioning alters responses for different parasites that vary in their biology (micro- and macro-parasite), transmission mode (direct, environmental, and vector transmitted) and duration of infection (acute, latent, and chronic). Next, we parameterised these different parasite types using data from the diverse parasite community of wild wood mice as a case study. We show there are common epidemiological responses to host resource provisioning across all parasite types examined. In particular, the response to provisioning could be driven in opposite directions, depending on which host pathways (contact rate, susceptibility or host demography) are most altered by the addition of resources to the environment. Broadly, these responses were qualitatively consistent across all parasite types, emphasising the importance of identifying general trade-offs between provisioning-altered parameters. Despite the qualitative consistency in responses to provisioning across parasite types, we found notable quantitative differences between parasites, suggesting specific epidemiological outcomes could strongly depend on parasite type, infection duration and permanency of recovery, and whether the parasite is directly, environmentally, or vector transmitted. These analyses therefore highlight the importance of knowing key specific aspects of host-parasite biology, such as host contact behaviours, parasite interactions with the host immune system, and how resource availability shapes host demographics, in order to understand and predict epidemiological responses to provisioning for any specific host-parasite system.

scholarly journals Membrane-Interactive Compounds from Pistacia lentiscus L. Thwart Pseudomonas aeruginosa Virulence

2020 ◽  
Author(s):  
Ali Tahrioui ◽  
Sergio Ortiz ◽  
Onyedikachi Cecil Azuama ◽  
Emeline Bouffartigues ◽  
Nabiha Benalia ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Wall Stress ◽  
Host Immune System ◽  
Pistacia Lentiscus ◽  
Regulatory Pathways ◽  
Ginkgolic Acid ◽  
Host Infection ◽  
Promising Perspective ◽  
Membrane Interactive

ABSTRACTPseudomonas aeruginosa is capable to deploy a collection of virulence factors that are not only essential for host infection and persistence, but also to escape from the host immune system and to become more resistant to drug therapies. Thus, developing anti-virulence agents that may directly counteract with specific virulence factors or disturb higher regulatory pathways controlling the production of virulence armories are urgently needed. In this regard, this study reports that Pistacia lentiscus L. fruit cyclohexane extract (PLFE1) thwarts P. aeruginosa virulence by targeting mainly the pyocyanin pigment production by interfering with 4-hydroxy-2-alkylquinolines molecules production. Importantly, the anti-virulence activity of PLFE1 appears to be associated with membrane homeostasis alteration through the modulation of SigX, an extracytoplasmic function sigma factor involved in cell wall stress response. A thorough chemical analysis of PLFE1 allowed us to identify the ginkgolic acid (C17:1) and hydroginkgolic acid (C15:0) as the main bioactive membrane-interactive compounds responsible for the observed increased membrane stiffness and anti-virulence activity against P. aeruginosa. This study delivers a promising perspective for the potential future use of PLFE1 or ginkgolic acid molecules as an adjuvant therapy to fight against P. aeruginosa infections.

Marine glycosaminoglycan-like carbohydrates as potential drug candidates for infectious disease

2018 ◽  
Vol 46 (4) ◽  
pp. 919-929 ◽  
Author(s):  
Courtney J. Mycroft-West ◽  
Edwin A. Yates ◽  
Mark A. Skidmore
Keyword(s):  
Infectious Disease ◽  
Antimicrobial Properties ◽  
Marine Species ◽  
Host Cells ◽  
Host Immune System ◽  
Potential Drug ◽  
Drug Candidates ◽  
Disease States ◽  
Cellular Attachment ◽  
Potential Use

Glycosaminoglycans (GAGs), present in the extracellular matrix, are exploited by numerous, distinct microbes for cellular attachment, adhesion, invasion and evasion of the host immune system. Glycosaminoglycans, including the widely used, clinical anticoagulant heparin and semi-synthetic analogues thereof, have been reported to inhibit and disrupt interactions between microbial proteins and carbohydrates present on the surface of host cells. However, the anticoagulant properties of unmodified, pharmaceutical heparin preparations preclude their capabilities as therapeutics for infectious disease states. Here, unique Glycosaminoglycan-like saccharides from various, distinct marine species are reported for their potential use as therapeutics against infectious diseases; many of which possess highly attenuated anticoagulant activities, while retaining significant antimicrobial properties.

scholarly journals An alternative route of bacterial infection associated with a novel resistance locus in the Daphnia–Pasteuria host–parasite system

Heredity ◽  
2020 ◽  
Vol 125 (4) ◽  
pp. 173-183
Author(s):  
Gilberto Bento ◽  
Peter D. Fields ◽  
David Duneau ◽  
Dieter Ebert
Keyword(s):  
Host Resistance ◽  
Natural Populations ◽  
Attachment Site ◽  
Genomic Region ◽  
Infection Process ◽  
Resistance Locus ◽  
Significant Qtls ◽  
Novel Host ◽  
Trait Locus ◽  
Host Parasite

Abstract To understand the mechanisms of antagonistic coevolution, it is crucial to identify the genetics of parasite resistance. In the Daphnia magna–Pasteuria ramosa host–parasite system, the most important step of the infection process is the one in which P. ramosa spores attach to the host’s foregut. A matching-allele model (MAM) describes the host–parasite genetic interactions underlying attachment success. Here we describe a new P. ramosa genotype, P15, which, unlike previously studied genotypes, attaches to the host’s hindgut, not to its foregut. Host resistance to P15 attachment shows great diversity across natural populations. In contrast to P. ramosa genotypes that use foregut attachment, P15 shows some quantitative variation in attachment success and does not always lead to successful infections, suggesting that hindgut attachment represents a less-efficient infection mechanism than foregut attachment. Using a Quantitative Trait Locus (QTL) approach, we detect two significant QTLs in the host genome: one that co-localizes with the previously described D. magna PR locus of resistance to foregut attachment, and a second, major QTL located in an unlinked genomic region. We find no evidence of epistasis. Fine mapping reveals a genomic region, the D locus, of ~13 kb. The discovery of a second P. ramosa attachment site and of a novel host-resistance locus increases the complexity of this system, with implications for both for the coevolutionary dynamics (e.g., Red Queen and the role of recombination), and for the evolution and epidemiology of the infection process.

scholarly journals Clinical Candida albicans Vaginal Isolates and a Laboratory Strain Show Divergent Behaviors during Macrophage Interactions

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Franziska Gerwien ◽  
Christine Dunker ◽  
Philipp Brandt ◽  
Enrico Garbe ◽  
Ilse D. Jacobsen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Infections ◽  
Laboratory Strain ◽  
Infection Process ◽  
Vulvovaginal Candidiasis ◽  
Host Immune System ◽  
Host Pathogen Interactions ◽  
Content Type ◽  
Host Pathogen

ABSTRACT Typically, established lab strains are widely used to study host-pathogen interactions. However, to better reflect the infection process, the experimental use of clinical isolates has come more into focus. Here, we analyzed the interaction of multiple vaginal isolates of the opportunistic fungal pathogen Candida albicans, the most common cause of vulvovaginal candidiasis in women, with key players of the host immune system: macrophages. We tested several strains isolated from asymptomatic or symptomatic women with acute and recurrent infections. While all clinical strains showed a response similar to the commonly used lab strain SC5314 in various in vitro assays, they displayed remarkable differences during interaction with macrophages. This coincided with significantly reduced β-glucan exposure on the cell surface, which appeared to be a shared property among the tested vaginal strains for yeast extract/peptone/dextrose-grown cells, which is partly lost when the isolates faced vaginal niche-like nutrient conditions. However, macrophage damage, survival of phagocytosis, and filamentation capacities were highly strain-specific. These results highlight the high heterogeneity of C. albicans strains in host-pathogen interactions, which have to be taken into account to bridge the gap between laboratory-gained data and disease-related outcomes in an actual patient. IMPORTANCE Vulvovaginal candidiasis is one of the most common fungal infections in humans with Candida albicans as the major causative agent. This study is the first to compare clinical vaginal isolates of defined patient groups in their interaction with macrophages, highlighting the vastly different outcomes in comparison to a laboratory strain using commonly applied virulence-determining assays.

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