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71.
Visceral leishmaniasis is a major neglected tropical disease, with an estimated 500,000 new cases and more than 50,000 deaths attributable to this disease every year. Drug therapy is available but costly and resistance against several drug classes has evolved. Despite all efforts, no commercial, let alone affordable, vaccine is available to date. Thus, the development of cost effective, needle-independent vaccines is a high priority. Here, we have continued efforts to develop live vaccine carriers based on recombinant Salmonella. We used an in silico approach to select novel Leishmania parasite antigens from proteomic data sets, with selection criteria based on protein abundance, conservation across Leishmania species and low homology to host species. Five chosen antigens were differentially expressed on the surface or in the cytosol of Salmonella typhimurium SL3261. A two-step procedure was developed to select optimal Salmonella vaccine strains for each antigen, based on bacterial fitness and antigen expression levels. We show that vaccine strains of Salmonella expressing the novel Leishmania antigens LinJ08.1190 and LinJ23.0410 significantly reduced visceralisation of L. major and enhanced systemic resistance against L. donovani in susceptible BALB/c mice. The results show that Salmonella are valid vaccine carriers for inducing resistance against visceral leishmaniasis but that their use may not be suitable for all antigens. 相似文献
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B. Nemry L. FrançOis J. -C. Grard A. Bondeau M. Heimann ThE. Participants OF. ThE. Potsdam NpP. Model Intercomparison 《Global Change Biology》1999,5(Z1):65-76
Eight terrestrial biospheric models (TBMs) calculating the monthly distributions of both net primary productivity (NPP) and soil heterotrophic respiration (RH) in the Potsdam NPP Model Intercomparison workshop are used to simulate seasonal patterns of atmospheric CO2 concentration. For each model, we used net ecosystem productivity (NEP = NPP – RH) as the source function in the TM2 atmospheric transport model from the Max-Planck Institute for Meteorology. Comparing the simulated concentration fields with detrended measurements from 25 monitoring stations spread over the world, we found that the decreasing seasonal amplitude from north to south is rather well reproduced by all the models, though the amplitudes are slightly too low in the north. The agreement between the simulated and observed seasonality is good in the northern hemisphere, but poor in the southern hemisphere, even when the ocean is accounted for. Based on a Fourier analysis of the calculated zonal atmospheric signals, tropical NEP plays a key role in the seasonal cycle of the atmospheric CO2 in the whole southern hemisphere. The relatively poor match between measured and predicted atmospheric CO2 in this hemisphere suggests problems with all the models. The simulation of water relations, a dominant regulator of NEP in the tropics, is a leading candidate for the source of these problems. 相似文献
75.
Olivier Gilg David Boertmann Flemming Merkel Adrian Aebischer Brigitte Sabard 《Polar Biology》2009,32(9):1275-1286
The ivory gull, a rare high-Arctic species whose main habitat throughout the year is sea ice, is currently listed in Greenland
as ‘Vulnerable’, and as ‘Endangered’ in Canada, where the population declined by 80% in 20 years. Despite this great concern,
the status of the species in Greenland has been largely unknown as it breeds in remote areas and in colonies for which population
data has rarely, if at all, been collected. Combining bibliographical research, land surveys, aerial surveys and satellite
tracking, we were able to identify 35 breeding sites, including 20 new ones, in North and East Greenland. Most colonies are
found in North Greenland and the largest are located on islands and lowlands. The current best estimate for the size of the
Greenland population is approx. 1,800 breeding birds, but the real figure is probably >4,000 adult birds (i.e. >2,000 pairs)
since all colonies have not yet been discovered and since only 50% or less of the breeding birds are usually present in the
colonies at the time the censuses take place. Although this estimate is four to eight times higher than that previously arrived
at, the species seems to be declining in the south of its Greenland breeding range, while in North Greenland the trends are
unclear and unpredictable, calling for increased monitoring efforts. 相似文献
76.
Temporal changes in the breeding ecology of European Turtle Doves Streptopelia turtur in Britain, and implications for conservation 总被引:3,自引:1,他引:2
The migratory European Turtle Dove Streptopelia turtur has undergone a 69% decline in population size and a 25% contraction in breeding range in Britain over the last 30 years. An investigation of the breeding ecology of this summer visitor was undertaken in 1998–2000 at two study sites in East Anglia, England. The only previous study of Turtle Dove reproduction in Britain provided pre-decline data for comparison with the current situation in a modern agricultural environment. Territory sizes ranged from 1.91 to 3.08 ha, were established in areas with scrub, hedges and woodland and contained less cropped land than expected from its availability. The majority of nests were sited 1–3 m above ground level within thorny bushes, particularly Hawthorn Crataegus monogyna . Nests found by radiotelemetry were significantly higher above ground level and were found in greater numbers than expected in woodland and coniferous trees than those found by cold searching, which were lower and found predominantly in hedges and thorny bushes. Turtle Dove nest success rate averaged 53% during incubation and 65% during the nestling stage, so that only 35% of nests successfully produced young. A comparison with data collected during the 1960s showed that Turtle Doves today have a shorter breeding season and consequently produce about half the number of clutches and young per pair than formerly. A simple simulation model suggested that the reduction in productivity alone would lead to a population decline of 17% per annum. This study suggests that the recovery of Turtle Doves in Britain is dependent upon the provision and sympathetic management of nesting and foraging habitats. The current arrangements for set-aside and agri-environmental schemes provide the framework for delivering these requirements. 相似文献
77.
Background: A vaccine against Helicobacter pylori would be a desirable alternative to antibiotic therapy. Vaccination has been shown to be effective in animal models but the mechanism of protection is poorly understood. Previous studies investigating the gene expression in stomachs of vaccinated mice showed changes in adipokine expression correlated to a protective response. In this study, we investigate a well-characterized adipokine-leptin, and reveal an important role for leptin receptor signaling in vaccine-induced protection.
Materials and Methods: Leptin receptor signaling-deficient (C57BL/Ks Leprdb ), wild-type C57BL/Ks m littermates and C57BL/6 mice were vaccinated, and then challenged with H. pylori . Levels of bacterial colonization, antibody levels, and gastric infiltrates were compared. The local gene expression pattern in the stomach of leptin receptor signaling-deficient and wild-type mice was also compared using microarrays.
Results: Interestingly, while vaccinated wild-type lean C57BL/6 and C57BL/Ks m mice were able to significantly reduce colonization compared to controls, vaccinated obese C57BL/Ks Leprdb were not. All mice responded to vaccination, i.e. developed infiltrates predominantly of T lymphocytes in the gastric mucosa, and made H. pylori -specific antibodies. A comparison of expression profiles in protected C57BL/6 and nonprotected C57BL/Ks Leprdb mice revealed a subset of inflammation-related genes that were more strongly expressed in nonprotected mice.
Conclusions: Our data suggest that functional leptin receptor signaling is required for mediating an effective protective response against H. pylori . 相似文献
Materials and Methods: Leptin receptor signaling-deficient (C57BL/Ks Lepr
Results: Interestingly, while vaccinated wild-type lean C57BL/6 and C57BL/Ks m mice were able to significantly reduce colonization compared to controls, vaccinated obese C57BL/Ks Lepr
Conclusions: Our data suggest that functional leptin receptor signaling is required for mediating an effective protective response against H. pylori . 相似文献
78.
79.
Goralczyk R Wertz K Lenz B Riss G Buchwald Hunziker P Geatrix B Aebischer CP Bachmann H 《Biochimica et biophysica acta》2005,1740(2):179-188
We studied the influence of beta-carotene on the tobacco smoke carcinogen 4-(N-Methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumor development in the A/J-mouse model. The normally low beta-carotene absorption was facilitated with a diet enriched in fat and bile salt, resulting in plasma and lung tissue levels similar to humans. beta-Carotene enhanced NNK-induced early bronchial cell proliferation, however, this effect was not predictive for later tumor development. Tumor multiplicity was not significantly affected by beta-carotene, neither in carcinogen-initiated nor in uninitiated mice, and regardless of dose and time point of supplementation during tumor development. RARbeta isoform and CYP26 gene expression levels analyzed by quantitative RT-PCR were weakly, but significantly, inversely correlated and showed evidence for altered retinoid signaling and catabolism in the lungs of NNK-initiated, beta-carotene supplemented mice. However, this interaction did not translate into enhanced tumor multiplicity. These results indicate that impaired retinoid signaling is not likely a key factor in lung tumorigenesis in this mouse model. 相似文献
80.
Haas G Karaali G Ebermayer K Metzger WG Lamer S Zimny-Arndt U Diescher S Goebel UB Vogt K Roznowski AB Wiedenmann BJ Meyer TF Aebischer T Jungblut PR 《Proteomics》2002,2(3):313-324
The Gram negative bacterium Helicobacter pylori is a human pathogen which infects the gastric mucosa and causes an inflammatory process leading to gastritis, ulceration and cancer. A systematic, proteome based approach was chosen to detect candidate antigens of H. pylori for diagnosis, therapy and vaccine development and to investigate potential associations between specific immune responses and manifestations of disease. Sera from patients with active H. pylori infection (n = 24), a control group with unrelated gastric disorders (n = 12) and from patients with gastric cancer (n = 6) were collected and analyzed for the reactivity against proteins of the strain HP 26695 separated by two-dimensional electrophoresis. Overall, 310 antigenic protein species were recognized by H. pylori positive sera representing about 17% of all spots separated. Out of the 32 antigens most frequently recognized by H. pylori positive sera, nine were newly identified and 23 were confirmed from other studies. Three newly identified antigens which belong to the 150 most abundant protein species of H. pylori, were specifically recognized by H. pylori positive sera: the predicted coding region HP0231, serine protease HtrA (HP1019) and Cag3 (HP0522). Other antigens were recognized differently by sera from gastritis and ulcer patients, which may identify them as candidate indicators for clinical manifestations. The data from these immunoproteomic analyses are added to our public database (http://www.mpiib-berlin.mpg.de/2D-PAGE). This platform enables one to compile many protein profiles and to integrate data from other studies, an approach which will greatly assist the search for more immunogenic proteins for diagnostic assays and vaccine design. 相似文献