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Host's Ability (host + ability)
Selected AbstractsParasitized Salamanders are Inferior Competitors for Territories and Food ResourcesETHOLOGY, Issue 4 2000Daria S. Maksimowich Parasites have been shown to impair the behaviour of their hosts, compromising the host's ability to exploit and compete for resources. We conducted two experiments to determine whether infestation with an ectoparasitic mite (Hannemania eltoni) was associated with changes in aggressive and foraging behaviour in the Ozark zigzag salamander, Plethodon angusticlavius. In a first experiment, male salamanders with high parasite loads were less aggressive overall than males with low parasite loads during territorial disputes. In addition, males with high parasite loads were more aggressive toward opponents with high parasite loads (symmetric contests) than toward opponents with low parasite loads (asymmetric contests). In contrast, males with low parasite loads did not adjust their level of aggression according to the parasite load of the opponent. In a second experiment, foraging behaviour of females was tested in response to ,familiar' (Drosophila) prey and ,novel' (termite) prey. Latency to first capture was significantly longer for parasitized than non-parasitized females when tested with ,familiar' prey, but not for ,novel' prey. Our results suggest that parasite-mediated effects may have profound influences on individual fitness in nature. [source] TLR2 Arg753Gly, TLR4 Asp299Gly and Thr399Ile gene polymorphisms are not associated with chronic periodontitis in a Turkish populationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2007Afig Berdeli Abstract Aim: Toll-like receptor (TLR) gene polymorphisms could affect the host's ability to respond to microbial pathogens. In this case,control study, the association of TLR2 and TLR4 gene polymorphisms with chronic periodontitis (CP) was investigated. Materials and Methods: Genomic DNA was obtained from the peripheral blood of 83 patients with CP and 106 periodontally healthy subjects. The TLR2 Arg753Gly, Arg677Trp and TLR4 Asp299Gly, Thr399Ile gene polymorphisms were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method. The data were analysed by a ,2 test, logistic regression analysis and the Mann,Whitney U test. Results: The 753Gln allele was found in 6.1% of the CP patients as compared with 6.6% in the control group (p>0.05). The frequency of the 299Gly and 399Ile allele was 2.4% and 1.8% in CP patients. For the healthy subjects, the frequency was 2.8% for the 299Gly and 2.5% for the 399Ile allele (p>0.05). None of the CP patients or healthy subjects showed homozygosity for the TLR2 and TLR4 alleles. Percentage of sites with bleeding on probing and plaque were significantly higher in 299Gly-positive patients compared with 299Gly-negative patients (p<0.05). Conclusion: These results showed that the TLR2 and TLR4 gene polymorphisms studied are not associated with susceptibility to CP in Turkish patients. [source] Alternative measures of response to Pseudomonas aeruginosa infection in Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2007V. CORBY-HARRIS Abstract Studies of invertebrate immune defence often measure genetic variation either for the fitness cost of infection or for the ability of the host to clear the parasite. These studies assume that variation in measures of resistance is related to variation in fitness costs of infection. To test this assumption, we infected strains of the fruit fly, Drosophila melanogaster, with a pathogenic bacterium. We then measured the correlation between host bacterial load and the ability to survive infection. Despite the presence of genotypic variation for both traits, bacterial load and survival post-infection were not correlated. Our results support previous arguments that individual measures of immune function and the host's ability to survive infection may be decoupled. In light of these results, we suggest that the difference between tolerance and resistance to infection, a distinction commonly found in the plant literature, may also be of value in studies of invertebrate immunity. [source] Brief Definitive Report: Human visceral leishmaniasis is not associated with expansion or accumulation of Foxp3+ CD4 cells in blood or spleenPARASITE IMMUNOLOGY, Issue 7 2010R. MAURYA Summary Natural regulatory T cells (CD4+ CD25+ Foxp3+), natural regulatory T cells (nTreg), play an important role in the regulation of inflammatory immune responses. However, the immunosuppressive properties of nTreg may unfavourably affect the host's ability to clear certain infections. In human visceral leishmaniasis (VL), reports on the frequency and function of nTreg are not conclusive. A limitation of our own previous studies that did not indicate a major role for Foxp3+ nTreg in VL pathogenesis was that Foxp3 was measured by mRNA expression alone, as other tools were not available at the time. We have in this study assessed CD4+CD25+Foxp3+ cells in splenic aspirates and peripheral blood mononuclear cells (PBMC) from an extensive series of patients with VL and endemic controls (EC) by flow cytometry (FACS). The results do not show increased frequencies of Foxp3+ cells in patient with VL pre- and post-treatment, neither were they elevated when compared to PBMC of EC. We conclude that active VL is not associated with increased frequencies of peripheral Foxp3 Treg or accumulation at the site of infection. [source] | |||||||||||||