81 research outputs found

    Do Termites Avoid Carcasses? Behavioral Responses Depend on the Nature of the Carcasses

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    BACKGROUND: Undertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) (lower termites) and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites). We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses) and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1) the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2) the termites repeatedly crawled under the aging carcass piles; and (3) only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature. CONCLUSION: We conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species

    Nucleolar Proteins Suppress Caenorhabditis elegans Innate Immunity by Inhibiting p53/CEP-1

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    The tumor suppressor p53 has been implicated in multiple functions that play key roles in health and disease, including ribosome biogenesis, control of aging, and cell cycle regulation. A genetic screen for negative regulators of innate immunity in Caenorhabditis elegans led to the identification of a mutation in NOL-6, a nucleolar RNA-associated protein (NRAP), which is involved in ribosome biogenesis and conserved across eukaryotic organisms. Mutation or silencing of NOL-6 and other nucleolar proteins results in an enhanced resistance to bacterial infections. A full-genome microarray analysis on animals with altered immune function due to mutation in nol-6 shows increased transcriptional levels of genes regulated by a p53 homologue, CEP-1. Further studies indicate that the activation of innate immunity by inhibition of nucleolar proteins requires p53/CEP-1 and its transcriptional target SYM-1. Since nucleoli and p53/CEP-1 are conserved, our results reveal an ancient immune mechanism by which the nucleolus may regulate immune responses against bacterial pathogens

    Home visitation program effectiveness and the influence of community behavioral norms: a propensity score matched analysis of prenatal smoking cessation

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    <p>Abstract</p> <p>Background</p> <p>The influence of community context on the effectiveness of evidence-based maternal and child home visitation programs following implementation is poorly understood. This study compared prenatal smoking cessation between home visitation program recipients and local-area comparison women across 24 implementation sites within one state, while also estimating the independent effect of community smoking norms on smoking cessation behavior.</p> <p>Methods</p> <p>Retrospective cohort design using propensity score matching of Nurse-Family Partnership (NFP) clients and local-area matched comparison women who smoked cigarettes in the first trimester of pregnancy. Birth certificate data were used to classify smoking status. The main outcome measure was smoking cessation in the third trimester of pregnancy. Multivariable logistic regression analysis examined, over two time periods, the association of NFP exposure and the association of baseline county prenatal smoking rate on prenatal smoking cessation.</p> <p>Results</p> <p>The association of NFP participation and prenatal smoking cessation was stronger in a later implementation period (35.5% for NFP clients vs. 27.5% for comparison women, p < 0.001) than in an earlier implementation period (28.4% vs. 25.8%, p = 0.114). Cessation was also negatively associated with county prenatal smoking rate, controlling for NFP program effect, (OR = 0.84 per 5 percentage point change in county smoking rate, p = 0.002).</p> <p>Conclusions</p> <p>Following a statewide implementation, program recipients of NFP demonstrated increased smoking cessation compared to comparison women, with a stronger program effect in later years. The significant association of county smoking rate with cessation suggests that community behavioral norms may present a challenge for evidence-based programs as models are translated into diverse communities.</p
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