Variation in immune defence among populations of Gammarus pulex (Crustacea: Amphipoda)

Cornet, Stéphane; Biard, Clotilde; Moret, Yannick

doi:10.1007/s00442-008-1211-y

Cited by 46 publications

(46 citation statements)

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“…However, in preliminary data for this study, and subsequent experiments, PO activity was found to be the more variable parameter compared to ProPO activity; the high variation in honey bee PO activity levels associated with seasonal and treatment effects could cause the ratio of PO to ProPO activity to drop as low as 1 in 50 in some cases (Laughton, 2008). This difference in plasticity between the two measures was also found in G. pulex (Cornet et al, 2009b), and may represent the transient nature of active PO in the haemolymph, and the variation in the relative costs of maintaining the two immune responses. Consequently, the choice of assay within a study should be carefully considered to reflect the questions being asked.…”

Section: Discussionsupporting

confidence: 54%

A standardised protocol for measuring phenoloxidase and prophenoloxidase in the honey bee, Apis mellifera

Laughton¹,

Siva‐Jothy²

2011

Apidologie

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-The prophenoloxidase activating system (ProPO-AS) is an integral part of the constitutive innate immune response in insects, the products of which are commonly assayed to assess an individual's ability to respond to immune challenges. However, there is considerable variation in the methodologies associated with these assays, and as such, it is not always clear how to interpret results. We have optimised assays for measuring phenoloxidase in its active (PO) and zymogen (ProPO) forms in the honey bee, Apis mellifera. Contrary to results for other insects, we found that the activator α-chymotrypsin, when used at a low concentration (0.5 mg mL −1 ), combined with a minimal activation time (5 min), provided optimal conditions for assaying ProPO. In addition, a saturated L-dopa solution was required for assaying both PO and ProPO. The results highlight the importance of defining the working parameters of each assay to be species-specific. honey bee / Apis mellifera / phenoloxidase / innate immunity / activator INTRODUCTIONThe innate immune system of insects consists of two broad categories of effectors: constitutive and induced (Schmid-Hempel, 2005). Constitutive responses generally comprise the humoral prophenoloxidase activating system (ProPO-AS) and cellular responses including coagulation, phagocytosis, nodule formation and encapsulation (Gillespie et al., 1997).Whilst not maintained at a constant maximum, constitutive immune responses are always present Cerenius et al., 2008), are non-specific but immediate in effect, and are responsible for clearing most of a microbial challenge very rapidly after infection (Haine et al., 2008). By contrast the induced responses, such as antimicrobial pepCorresponding author: A.M. Laughton, alice.laughton@emory.edu * Manuscript editor: Bernd Grünewald tides, occur only once the invading pathogen has been recognised. They are specific and take longer to produce, but are longer lasting in their effect (Boman and Hultmark, 1987).We concentrate on one important arm of the constitutive immune responses. The ProPO-AS is a series of complex interactions between enzymes and their zymogens, leading to the production the enzyme phenoloxidase (PO; monophenol, L-dopa:oxygen oxidoreductase, EC 1.14.18.1). PO activity ultimately results in the formation of melanin, which is subsequently involved in cuticle sclerotisation, wound healing and cellular defence responses (Mason, 1955;Ratcliffe et al., 1984;Cerenius et al., 2008). Due to the cytotoxic nature of the by-products of this process, PO is commonly stored as its inactive precursor prophenoloxidase (ProPO), and activated as part of the cascade following the recognition of foreign compounds (Ratcliffe et al., 1984;Riley, 1988; Gillespie et al., 1997; Söderhäll and Apidologie (2011) 42:1 -1

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Section: Discussionsupporting

confidence: 54%

A standardised protocol for measuring phenoloxidase and prophenoloxidase in the honey bee, Apis mellifera

Laughton¹,

Siva‐Jothy²

2011

Apidologie

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“…Given the global rise in disease epizootics (Harvell et al, 2002;Lafferty, 2009), the development of ecological immunology and its application to threatened keystone species is particularly timely. However, there are few investigations into variation in baseline immunity or immune responses of natural populations (Cornet et al, 2009;Palmer et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Patterns of coral ecological immunology: variation in the responses of Caribbean corals to elevated temperature and a pathogen elicitor

Palmer

McGinty

Cummings

et al. 2011

Journal of Experimental Biology

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SUMMARYDisease epizootics are increasing with climatic shifts, yet within each system only a subset of species are identified as the most vulnerable. Understanding ecological immunology patterns as well as environmental influences on immune defenses will provide insight into the persistence of a functional system through adverse conditions. Amongst the most threatened ecosystems are coral reefs, with coral disease epizootics and thermal stress jeopardizing their survival. Immune defenses were investigated within three Caribbean corals, Montastraea faveolata, Stephanocoenia intersepta and Porites astreoides, which represent a range of disease and bleaching susceptibilities. Levels of several immune parameters were measured in response to elevated water temperature and the presence of a commercial pathogen-associated molecular pattern (PAMP) -lipopolysaccharide (LPS) -as an elicitor of the innate immune response. Immune parameters included prophenoloxidase (PPO) activity, melanin concentration, bactericidal activity, the antioxidants peroxidase and catalase, and fluorescent protein (FP) concentration. LPS induced an immune response in all three corals, although each species responded differently to the experimental treatments. For example, M. faveolata, a disease-susceptible species, experienced significant decreases in bactericidal activity and melanin concentration after exposure to LPS and elevated temperature alone. Porites astreoides, a disease-resistant species, showed increased levels of enzymatic antioxidants upon exposure to LPS independently and increased PPO activity in response to the combination of LPS and elevated water temperature. This study demonstrates the ability of reef-building corals to induce immune responses in the presence of PAMPs, indicating activation of PAMP receptors and the transduction of appropriate signals leading to immune effector responses. Furthermore, these data address the emerging field of ecological immunology by highlighting interspecific differences in immunity and immunocompetences among Caribbean corals, which are reflected in their life-history characteristics, disease susceptibilities and bleaching-induced mortality.

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“…Before use, a 1 : 3 dilution of aged water with well-aerated control water was done. Gammarids were isolated in glass vials filled with 20 ml of either control or micro-organism-enriched water (Cornet et al 2009c). The water was renewed every 2 days to provide enough oxygen to the animals since the micro-organism-enriched water might be more rapidly impoverished in dissolved oxygen.…”

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confidence: 99%

Parasite virulence when the infection reduces the host immune response

Cornet

Sorci

2010

Proc. R. Soc. B.

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Parasite infections often induce a reduction in host immune response either because of a direct manipulation of the immune system by the parasite or because of energy depletion. Although infection-induced immunodepression can favour the establishment of the parasite within the host, a too severe immunodepression may increase the risk of infection with opportunistic pathogens, stopping the period over which the parasite can be transmitted to other hosts. Here, we explore how the risk of contracting opportunistic diseases affects the survival of the amphipod Gammarus pulex infected by the acanthocephalan Pomphorhynchus laevis. Previous work with this system has shown that upon infection, G. pulex has a substantially reduced immune response. Non-infected and P. laevis-infected hosts were maintained either in control or in micro-organism-enriched water, so as to vary the risk of encountering opportunistic pathogens. As predicted, we found that host mortality was exacerbated when infected gammarids were maintained in micro-organism-enriched water compared with clean, control water; whereas for noninfected gammarids, living in micro-organism-enriched water only moderately increased the risk of mortality. These results show that the virulence of parasites that reduce the host immune response is an environmentally sensitive trait that depends on the concomitant risk for the host of contracting opportunistic diseases. This extra source of host mortality probably represents a cost for P. laevis, and we tentatively predict that the optimal level of parasite exploitation should depend on environmental conditions.

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Variation in immune defence among populations of Gammarus pulex (Crustacea: Amphipoda)

Cited by 46 publications

References 74 publications

A standardised protocol for measuring phenoloxidase and prophenoloxidase in the honey bee, Apis mellifera

A standardised protocol for measuring phenoloxidase and prophenoloxidase in the honey bee, Apis mellifera

Patterns of coral ecological immunology: variation in the responses of Caribbean corals to elevated temperature and a pathogen elicitor

Parasite virulence when the infection reduces the host immune response

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