98 research outputs found

    Fighting a losing battle: Vigorous immune response countered by pathogen suppression of host defenses in the chytridiomycosis-susceptible frog Atelopus zeteki

    Get PDF
    The emergence of the disease chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in dramatic global amphibian declines. Although many species have undergone catastrophic declines and/or extinctions, others appear to be unaffected or persist at reduced frequencies after Bd outbreaks. The reasons behind this variance in disease outcomes are poorly understood: differences in host immune responses have been proposed, yet previous studies suggest a lack of robust immune responses to Bd in susceptible species. Here, we sequenced transcriptomes from clutchmates of a highly susceptible amphibian, Atelopus zeteki, with different infection histories. We found significant changes in expression of numerous genes involved in innate and inflammatory responses in infected frogs despite high susceptibility to chytridiomycosis. We show evidence of acquired immune responses generated against Bd, including increased expression of immunoglobulins and major histocompatibility complex genes. In addition, fungal-killing genes had significantly greater expression in frogs previously exposed to Bd compared with Bd-naïve frogs, including chitinase and serine-type proteases. However, our results appear to confirm recent in vitro evidence of immune suppression by Bd, demonstrated by decreased expression of lymphocyte genes in the spleen of infected compared with control frogs. We propose susceptibility to chytridiomycosis is not due to lack of Bd-specific immune responses but instead is caused by failure of those responses to be effective. Ineffective immune pathway activation and timing of antibody production are discussed as potential mechanisms. However, in light of our findings,suppression of key immune responses by Bd is likely an important factor in the lethality of this fungus

    More than skin deep: Functional genomic basis for resistance to Amphibian Chytridiomycosis

    Get PDF
    The amphibian-killing chytrid fungus Batrachochytriumdendrobatidis (Bd) is one of themost generalist pathogens known, capable of infecting hundreds of species globally and causing widespread population declines and extinctions. However, some host species are seemingly unaffected by Bd, tolerating or clearing infections without clinical signs of disease. Variation in host immune responses is commonly evoked for these resistant or tolerant species, yet to date,we have nodirect comparisonof amphibian species responses to infection at the level of gene expression. In this study,we challenged four CentralAmerican frog species that vary in Bd susceptibility, with a sympatric virulent strain of the pathogen. We compared skin and spleen orthologous gene expression using differential expression tests and coexpression gene network analyses.Wefound that resistant species have reduced skin inflammatory responses andincreased expressionofgenes involved inskin integrity. Incontrast, onlyhighly susceptible species exhibited suppressionof splenic T-cell genes. We conclude that resistance to chytridiomycosis may be related to a species’ ability to escape the immunosuppressive activity of the fungus. Moreover, our results indicate that within-species differences in splenic proteolytic enzyme gene expression may contribute to intraspecific variation in survival. This first comparison of amphibian functional immunogenomic architecture in response to Bd provides insights into key genetic mechanisms underlying variation in disease outcomes among amphibian species

    Non-perturbative Landau gauge and infrared critical exponents in QCD

    Get PDF
    We discuss Faddeev-Popov quantization at the non-perturbative level and show that Gribov's prescription of cutting off the functional integral at the Gribov horizon does not change the Schwinger-Dyson equations, but rather resolves an ambiguity in the solution of these equations. We note that Gribov's prescription is not exact, and we therefore turn to the method of stochastic quantization in its time-independent formulation, and recall the proof that it is correct at the non-perturbative level. The non-perturbative Landau gauge is derived as a limiting case, and it is found that it yields the Faddeev-Popov method in Landau gauge with a cut-off at the Gribov horizon, plus a novel term that corrects for over-counting of Gribov copies inside the Gribov horizon. Non-perturbative but truncated coupled Schwinger-Dyson equations for the gluon and ghost propagators D(k)D(k) and G(k)G(k) in Landau gauge are solved asymptotically in the infrared region. The infrared critical exponents or anomalous dimensions, defined by D(k)1/(k2)1+aDD(k) \sim 1/(k^2)^{1 + a_D} and G(k)1/(k2)1+aGG(k) \sim 1/(k^2)^{1 + a_G} are obtained in space-time dimensions d=2,3,4d = 2, 3, 4. Two possible solutions are obtained with the values, in d=4d = 4 dimensions, aG=1,aD=2a_G = 1, a_D = -2, or aG=[93(1201)1/2]/980.595353,aD=2aG a_G = [93 - (1201)^{1/2}]/98 \approx 0.595353, a_D = - 2a_G.Comment: 26 pages. Modified 2.25.02 to update references and to clarify Introduction and Conclusio

    Advances in estrogen receptor biology: prospects for improvements in targeted breast cancer therapy

    Get PDF
    Estrogen receptor (ER) has a crucial role in normal breast development and is expressed in the most common breast cancer subtypes. Importantly, its expression is very highly predictive for response to endocrine therapy. Current endocrine therapies for ER-positive breast cancers target ER function at multiple levels. These include targeting the level of estrogen, blocking estrogen action at the ER, and decreasing ER levels. However, the ultimate effectiveness of therapy is limited by either intrinsic or acquired resistance. Identifying the factors and pathways responsible for sensitivity and resistance remains a challenge in improving the treatment of breast cancer. With a better understanding of coordinated action of ER, its coregulatory factors, and the influence of other intracellular signaling cascades, improvements in breast cancer therapy are emerging

    Edible Halophytes and Halo-Tolerant Species in Apulia Region (Southeastern Italy): Biogeography, Traditional Food Use and Potential Sustainable Crops

    No full text
    The Mediterranean basin is rich in wild edible species which have been used for food and medicinal purposes by humans throughout the centuries. Many of these species can be found near coastal areas and usually grow under saline conditions, while others can adapt in various harsh conditions including high salinity. Many of these species have a long history of gathering from the wild as a source of food. The aim of this contribution is an overview on the most important halophyte species (Salicornia sp. pl., Arthrocaulon macrostachyum (Moric.) Piirainen & G. Kadereit, Soda inermis Fourr., Cakile maritima Scop., Crithmum maritimum L., Reichardia picroides (L.) Roth., Silene vulgaris (Moench) Garcke subsp. tenoreana (Colla) Soldano & F. Conti, Allium commutatum Guss., Beta vulgaris L. subsp. maritima (L.) Arcang., Capparis spinosa L.) that traditionally have been gathered by rural communities in southern Italy, with special interest on their ecology and distribution, traditional uses, medicinal properties, marketing and early attempts of cultivation. It is worth noting that these species have an attractive new cash crop for marsh marginal lands

    FOLFIRI with or without Celecoxib in avanced colorectal cancer: a randomized phase II study of the Gruppo Oncologico dell’ Italia Meridionale (GOIM)

    No full text
    Background: The aim of the study was to verify the efficacy and safety of the addition of celecoxib to FOLFIRI combination therapy in patients affected by advanced colorectal cancer. Patients and methods: Eighty-one chemotherapy-naı¨ve patients entered in this randomized phase II trial of the GOIM (protocol no. 2301). Patients were randomized to receive FOLFIRI regimen (arm A): irinotecan 180 mg/m2 on day 1 with LV5FU2 regimen (LV at 100 mg/m2 administered as a 2-h infusion before FU at 400 mg/m2 as an intravenous bolus injection, and FU at 600 mg/m2 as a 22-h infusion immediately after 5-FU bolus injection on day 1 and 2); or FOLFIRI plus celecoxib 400 mg twice daily for 14 days (arm B). Both treatments were repeated every 2 weeks. Results: Seventy-seven patients (38 in arm A and 39 in arm B) were evaluable for response. The overall response rate was 41% in arm A (95% CI 27% to 57%) and 35% in arm B (95% CI 20% to 50%). When only assessable patients were analyzed, overall response rate was 45% in arm A (95% CI 29% to 61%) and 36% in arm B (95% CI 21% to 51%). Median time to progression, median duration of response and survival were, respectively, 8 months, 9 months and 16 months in arm A, and 7 months, 9 months and 19 months in arm B. All patients were evaluable for toxicity, which was globally mild in both arms; grade 3–4 toxicity was uncommon, and gastrointestinal disturbances were the most common. Conclusions: FOLFIRI regimen is effective and well-tolerated as a first-line treatment in patients with advanced colorectal cancer. The addition of celecoxib to FOLFIRI regimen does not improve results

    A rare case of multiple sclerosis and McArdle disease

    No full text
    McArdle disease is the most common metabolic myopathy with autosomal recessive inheritance due to mutations in the gene PYGM encoding myophosphorylase. In this report, we describe the first case of a patient affected by MS and McArdle diseas
    corecore