Bacterial-induced Inflammation in Germ-free Rabbit Appendix

Shanmugam, Malathy; Sethupathi, Periannan; Rhee, Ki Jong; Yong, Sherri; Knight, Katherine L.

doi:10.1097/01.mib.0000182869.74648.0f

Cited by 16 publications

(12 citation statements)

References 22 publications

(48 reference statements)

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“…This model is derived, in part, from the mechanism of mammalian sepsis in which gut-derived microbiota serve as both sources of infectious bacteria and modulators of the innate immune system [51-54]. Germ-free mammals are less susceptible to sepsis, just as gypsy moth larvae lacking enteric bacteria are less susceptible to B. thuringiensis [53,55-57]. Further support for our model can be derived from recent work demonstrating that ingestion of non-pathogenic bacteria can induce the immune response of lepidopteran larvae [58].…”

Section: Discussionmentioning

confidence: 99%

Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis

2010

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BackgroundThe gut comprises an essential barrier that protects both invertebrate and vertebrate animals from invasion by microorganisms. Disruption of the balanced relationship between indigenous gut microbiota and their host can result in gut bacteria eliciting host responses similar to those caused by invasive pathogens. For example, ingestion of Bacillus thuringiensis by larvae of some species of susceptible Lepidoptera can result in normally benign enteric bacteria exerting pathogenic effects.ResultsWe explored the potential role of the insect immune response in mortality caused by B. thuringiensis in conjunction with gut bacteria. Two lines of evidence support such a role. First, ingestion of B. thuringiensis by gypsy moth larvae led to the depletion of their hemocytes. Second, pharmacological agents that are known to modulate innate immune responses of invertebrates and vertebrates altered larval mortality induced by B. thuringiensis. Specifically, Gram-negative peptidoglycan pre-treated with lysozyme accelerated B. thuringiensis-induced killing of larvae previously made less susceptible due to treatment with antibiotics. Conversely, several inhibitors of the innate immune response (eicosanoid inhibitors and antioxidants) increased the host's survival time following ingestion of B. thuringiensis.ConclusionsThis study demonstrates that B. thuringiensis infection provokes changes in the cellular immune response of gypsy moth larvae. The effects of chemicals known to modulate the innate immune response of many invertebrates and vertebrates, including Lepidoptera, also indicate a role of this response in B. thuringiensis killing. Interactions among B. thuringiensis toxin, enteric bacteria, and aspects of the gypsy moth immune response may provide a novel model to decipher mechanisms of sepsis associated with bacteria of gut origin.

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Section: Discussionmentioning

confidence: 99%

Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis

2010

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“…‘colonization resistance’ reviewed in Bik 2009). Individuals without microbiota are less capable of fighting bacterial, fungal or viral infections (Gilturnes & Fenical 1992; Shanmugam et al. 2005; Rawls et al.…”

Section: Measuring Immunitymentioning

confidence: 99%

“…'colonization resistance' reviewed in Bik 2009). Individuals without microbiota are less capable of fighting bacterial, fungal or viral infections (Gilturnes & Fenical 1992;Shanmugam et al 2005;Rawls et al 2006). Mechanisms to explain these complex interactions between parasites, the host's microbial flora and immune system are not yet fully understood (but see Rakoff-Nahoum et al 2004;Ryu et al 2008;Rodrigues et al 2010).…”

Section: Natural Parasites In the Host Organism And Their Interactionsmentioning

confidence: 99%

Outdoor immunology: methodological considerations for ecologists

2011

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Summary 1.Immune defence is an incredibly complicated system, but to understand how it functions in an ecological context is challenging. Our focus is to outline the diversity of ways to measure immune function for ecologists, and to provide some details on the limitations in interpretation of results. 2. There are two broad questions that ecological immunologists have to deal with. The first is what assays are appropriate for the research question of interest? Some researchers assume the biological relevance of an immune assay without investigation or a complete understanding of the immune response. Therefore, the second question is, what parasite challenge does one choose, and does a measurement of immune function reflect the response of the host towards that parasite? There are many assumptions, caveats, and pitfalls facing ecological immunologists, and investigating the relationships between immune assays and whole organismal defence will help us to understand variations in immune responses. 3. We provide an extensive listing of immune function measures, presenting examples from both the vertebrate and invertebrate literature, and wherever possible from non-model organisms. We also outline how these responses are part of an integrated immune defence and encourage thinking about immune function as a hierarchical defence model. We describe how immune responses interact with one another, identify concerns regarding when to measure an immune response, and describe general problems faced when trying to collect a measure of immune function in wild organisms. 4. Extrinsic factors influence immune measurements and the importance of parasites is often overlooked. We give several examples of how parasites interact with organism's immune systems, suggest greater inclusion of parasites into ecological immunology experiments, describe how micro-organisms may interact symbiotically with their host's immune system, and advocate the inclusion of tolerance and resistance in ecological immunological thinking.

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“…Thus, variation in microbial symbionts can support or hinder adaptation of the holobiont (coral host and associated microorganisms). In the absence of microorganisms, many eukaryotic organisms may be less able to fight infections from pathogenic bacteria and viruses (Shanmugam et al 2005). Microorganisms likely prevent infection by producing antibacterial and antifungal compounds in addition to occupying niches that would otherwise be available to opportunistic pathogens (Koh 1997;Castillo et al 2001;Ritchie 2006).…”

Section: Introductionmentioning

confidence: 99%

Allelochemicals produced by Caribbean macroalgae and cyanobacteria have species-specific effects on reef coral microorganisms

Morrow

Paul²,

Liles

et al. 2011

Coral Reefs

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Coral populations have precipitously declined on Caribbean reefs while algal abundance has increased, leading to enhanced competitive damage to corals, which likely is mediated by the potent allelochemicals produced by both macroalgae and benthic cyanobacteria. Allelochemicals may affect the composition and abundance of coral-associated microorganisms that control host responses and adaptations to environmental change, including susceptibility to bacterial diseases. Here, we demonstrate that extracts of six Caribbean macroalgae and two benthic cyanobacteria have both inhibitory and stimulatory effects on bacterial taxa cultured from the surfaces of Caribbean corals, macroalgae, and corals exposed to macroalgal extracts. The growth of 54 bacterial isolates was monitored in the presence of lipophilic and hydrophilic crude extracts derived from Caribbean macroalgae and cyanobacteria using 96-well plate bioassays. All 54 bacterial cultures were identified by ribotyping. Lipophilic extracts from two species of Dictyota brown algae inhibited[50% of the reef coral bacteria assayed, and hydrophilic compounds from Dictyota menstrualis particularly inhibited Vibrio bacteria, a genus associated with several coral diseases. In contrast, both lipo-and hydrophilic extracts from 2 species of Lyngbya cyanobacteria strongly stimulated bacterial growth. The brown alga Lobophora variegata produced hydrophilic compounds with broad-spectrum antibacterial effects, which inhibited 93% of the bacterial cultures. Furthermore, bacteria cultured from different locations (corals vs. macroalgae vs. coral surfaces exposed to macroalgal extracts) responded differently to algal extracts. These results reveal that extracts from macroalgae and cyanobacteria have species-specific effects on the composition of coral-microbial assemblages, which in turn may increase coral host susceptibility to disease and result in coral mortality.

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Bacterial-induced Inflammation in Germ-free Rabbit Appendix

Cited by 16 publications

References 22 publications

Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis

Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis

Outdoor immunology: methodological considerations for ecologists

Allelochemicals produced by Caribbean macroalgae and cyanobacteria have species-specific effects on reef coral microorganisms

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