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251.
Claudia Stamm Julia Barthelmann Natalia Kunz Kai-Michael Toellner Jürgen Westermann Kathrin Kalies 《PloS one》2013,8(6)
The differentiation of CD4 T cells into Th1 and Th2 cells in vivo is difficult to analyze since it is influenced by many factors such as genetic background of the mice, nature of antigen, and adjuvant. In this study, we used a well-established model, which allows inducing Th1 or Th2 cells simply by low (LD, 105) or high dose (HD, 109) injection of sheep red blood cells (SRBC) into C57BL/6 mice. Signature cytokine mRNA expression was determined in specific splenic compartments after isolation by laser-microdissection. LD immunization with SRBC induced T cell proliferation in the splenic T cell zone but no Th1 differentiation. A second administration of SRBC into the skin rapidly generated Th1 cells. In contrast, HD immunization with SRBC induced both T cell proliferation and immediate Th2 differentiation. In addition, splenic marginal zone and B cell zone were activated indicating B cells as antigen presenting cells. Interestingly, disruption of the splenic architecture, in particular of the marginal zone, abolished Th2 differentiation and led to the generation of Th1 cells, confirming that antigen presentation by B cells directs Th2 polarization. Only in its absence Th1 cells develop. Therefore, B cells might be promising targets in order to therapeutically modulate the T cell response. 相似文献
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Anthony S Amend Adam C Martiny Steven D Allison Renaud Berlemont Michael L Goulden Ying Lu Kathleen K Treseder Claudia Weihe Jennifer B H Martiny 《The ISME journal》2016,10(1):109-118
The high diversity of microbial communities hampers predictions about their responses to global change. Here we investigate the potential for using a phylogenetic, trait-based framework to capture the response of bacteria and fungi to global change manipulations. Replicated grassland plots were subjected to 3+ years of drought and nitrogen fertilization. The responses of leaf litter bacteria and fungi to these simulated changes were significantly phylogenetically conserved. Proportional changes in abundance were highly correlated among related organisms, such that relatives with approximately 5% ribosomal DNA genetic distance showed similar responses to the treatments. A microbe''s change in relative abundance was significantly correlated between the treatments, suggesting a compromise between numerical abundance in undisturbed environments and resistance to change in general, independent of disturbance type. Lineages in which at least 90% of the microbes shared the same response were circumscribed at a modest phylogenetic depth (τD 0.014–0.021), but significantly larger than randomized simulations predict. In several clades, phylogenetic depth of trait consensus was higher. Fungal response to drought was more conserved than was response to nitrogen fertilization, whereas bacteria responded equally to both treatments. Finally, we show that a bacterium''s response to the manipulations is correlated with its potential functional traits (measured here as the number of glycoside hydrolase genes encoding the capacity to degrade different types of carbohydrates). Together, these results suggest that a phylogenetic, trait-based framework may be useful for predicting shifts in microbial composition and functioning in the face of global change. 相似文献
254.
Marcelo Magioli Katia Maria Paschoaletto Micchi de Barros Ferraz Eleonore Zulnara Freire Setz Alexandre Reis Percequillo Michelle Viviane de Sá Santos Rondon Vanessa Villanova Kuhnen Mariana Cristina da Silva Canhoto Karen Evelyn Almeida dos Santos Claudia Zukeran Kanda Gabriela de Lima Fregonezi Helena Alves do Prado Mitra Katherina Ferreira Milton Cezar Ribeiro Priscilla Marqui Schmidt Villela Luiz Lehmann Coutinho Márcia Gonçalves Rodrigues 《European Journal of Wildlife Research》2016,62(4):431-446
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Maike Wolters Valeria Pala Paola Russo Patrizia Risé Luis A. Moreno Stefaan De Henauw Kirsten Mehlig Toomas Veidebaum Denés Molnár Michael Tornaritis Claudio Galli Wolfgang Ahrens Claudia B?rnhorst 《PloS one》2016,11(11)
BackgroundPolyunsaturated n-3 and n-6 polyunsaturated fatty acids (PUFA) are precursors of biologically active metabolites that affect blood pressure (BP) regulation. This study investigated the association of n-3 and n-6 PUFA and BP in children and adolescents.MethodsIn a subsample of 1267 children aged 2–9 years at baseline of the European IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) cohort whole blood fatty acids were measured by a validated gas chromatographic method. Systolic and diastolic BP was measured at baseline and after two and six years. Mixed-effects models were used to assess the associations between fatty acids at baseline and BP z-scores over time adjusting for relevant covariables. Models were further estimated stratified by sex and weight status.ResultsThe baseline level of arachidonic acid was positively associated with subsequent systolic BP (β = 0.08, P = 0.002) and diastolic BP (β = 0.07, P<0.001). In thin/normal weight children, baseline alpha-linolenic (β = -1.13, P = 0.003) and eicosapentaenoic acid (β = -0.85, P = 0.003) levels were inversely related to baseline and also to subsequent systolic BP and alpha-linolenic acid to subsequent diastolic BP. In overweight/obese children, baseline eicosapentaenoic acid level was positively associated with baseline diastolic BP (β = 0.54, P = 0.005).ConclusionsLow blood arachidonic acid levels in the whole sample and high n-3 PUFA levels in thin/normal weight children are associated with lower and therefore healthier BP. The beneficial effects of high n-3 PUFA on BP were not observed in overweight/obese children, suggesting that they may have been overlaid by the unfavorable effects of excess weight. 相似文献
259.
James Weger-Lucarelli Claudia Rückert Nunya Chotiwan Chilinh Nguyen Selene M. Garcia Luna Joseph R. Fauver Brian D. Foy Rushika Perera William C. Black Rebekah C. Kading Gregory D. Ebel 《PLoS neglected tropical diseases》2016,10(10)
In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus) emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC) of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas. 相似文献
260.
Anna Kuehne Emily Lynch Esaie Marshall Amanda Tiffany Ian Alley Luke Bawo Moses Massaquoi Claudia Lodesani Philippe Le Vaillant Klaudia Porten Etienne Gignoux 《PLoS neglected tropical diseases》2016,10(8)
Between March 2014 and July 2015 at least 10,500 Ebola cases including more than 4,800 deaths occurred in Liberia, the majority in Monrovia. However, official numbers may have underestimated the size of the outbreak. Closure of health facilities and mistrust in existing structures may have additionally impacted on all-cause morbidity and mortality. To quantify mortality and morbidity and describe health-seeking behaviour in Monrovia, Médecins sans Frontières (MSF) conducted a mobile phone survey from December 2014 to March 2015. We drew a random sample of households in Monrovia and conducted structured mobile phone interviews, covering morbidity, mortality and health-seeking behaviour from 14 May 2014 until the day of the survey. We defined an Ebola-related death as any death meeting the Liberian Ebola case definition. We calculated all-cause and Ebola-specific mortality rates. The sample consisted of 6,813 household members in 905 households. We estimated a crude mortality rate (CMR) of 0.33/10,000 persons/day (95%CI:0.25–0.43) and an Ebola-specific mortality rate of 0.06/10,000 persons/day (95%-CI:0.03–0.11). During the recall period, 17 Ebola cases were reported including those who died. In the 30 days prior to the survey 277 household members were reported sick; malaria accounted for 54% (150/277). Of the sick household members, 43% (122/276) did not visit any health care facility. The mobile phone-based survey was found to be a feasible and acceptable alternative method when data collection in the community is impossible. CMR was estimated well below the emergency threshold of 1/10,000 persons/day. Non-Ebola-related mortality in Monrovia was not higher than previous national estimates of mortality for Liberia. However, excess mortality directly resulting from Ebola did occur in the population. Importantly, the small proportion of sick household members presenting to official health facilities when sick might pose a challenge for future outbreak detection and mitigation. Substantial reported health-seeking behaviour outside of health facilities may also suggest the need for adapted health messaging and improved access to health care. 相似文献