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201.
Heterogeneity in environmental conditions helps to maintain genetic and phenotypic
diversity in ecosystems. As such, it may explain why the capacity of animals to mount
immune responses is highly variable. The quality of habitat patches, in terms of
resources, parasitism, predation and habitat fragmentation may, for example, trigger
trade-offs ultimately affecting the investment of individuals in various immunological
pathways. We described spatial immunoheterogeneity in bank vole populations with respect
to landscape features and co-infection. We focused on the consequences of this
heterogeneity for the risk of Puumala hantavirus (PUUV) infection. We assessed the
expression of the Tnf-α and Mx2 genes and demonstrated a negative
correlation between PUUV load and the expression of these immune genes in bank voles.
Habitat heterogeneity was partly associated with differences in the expression of these
genes. Levels of Mx2 were lower in large forests than in fragmented forests,
possibly due to differences in parasite communities. We previously highlighted the
positive association between infection with Heligmosomum mixtum and infection
with PUUV. We found that Tnf-α was more strongly expressed in voles
infected with PUUV than in uninfected voles or in voles co-infected with the
nematode H. mixtum and PUUV. H. mixtum may limit the capacity of the
vole to develop proinflammatory responses. This effect may increase the risk of PUUV
infection and replication in host cells. Overall, our results suggest that close
interactions between landscape features, co-infection and immune gene expression may shape
PUUV epidemiology. 相似文献
202.
Supplement comprising of laccase and citric acid as an alternative for antibiotics: In vitro triggers of melanin production
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Mona Chaali Joanna Lecka Gayatri Suresh Mabrouka Salem Satinder Kaur Brar Leticia Hernandez‐Galan Jean Sévigny Antonio Avalos‐Ramirez 《Engineering in Life Science》2018,18(6):359-367
An indiscriminate use of antibiotics in humans and animals has led to the widespread selection of antibiotic‐resistance, thus constricting the use of antibiotics. A possible solution to counter this problem could be to develop alternatives that can boost the host immunity, thus reducing the quantity and frequency of antibiotic use. In this work, for the first time, citric acid and laccase were used as extracellular inducers of melanin production in yeast cells and human cell lines. It is proposed that the formulation of laccase and citric acid together could further promote melatonin‐stimulated, melanocyte‐derived melanin production. Melanization as a probe of immunity described in this study, is an easy and a rapid test compared to other immunity tests and it allows performing statistical analyses. The results showed the synergistic effect of citric acid and laccase on melanin production by yeast cells, with significant statistical differences compared to all other tested conditions (p: 0.0005–0.005). Laccase and citric acid together boosted melanin production after 8 days of incubation. An increase in melanin production by two human colon cells lines (Cacao‐2/15 and HT‐29) was observed on supplementation with both laccase and citric acid in the cell growth medium. Produced melanin showed antimicrobial properties similar to antibiotics. Therefore, a formulation with citric acid and laccase may prove to be an excellent alternative to reduce the antibiotic use in human and animal subjects. 相似文献
203.
Wheat leaves were labelled with [l-14C]-glycerol or [l-14C]-acetateand chase experiments performed in the dark or under light.In plastids, both in the dark and under light, the results indicatea transfer of [l-14C]-glycerol from phospholipids to galactolipidsand of [l-14C]-acetate from phosphatidylcholine (PC) to monogalactosyldiacylglycerol (MGDG). They also argue for a transfer of [l-14C]-glyceroland [1-14C]-acetate from phosphatidylcholine (PC) to phosphatidylethanolamine(PE) in extraplastidial membranes. During chase experimentsin the dark, the chloroplasts accumulated higher amounts ofradioactive precursor in saturated fatty acids. In the darkor under light, oleoyl-PC labelling equally decreased in plastids,but decreased much more under light in extraplastidial membranes.Light enhanced polyunsaturated fatty acid synthesis, mainlyin MGDG, PC, PE and plastidial phosphatidylglycerol (PG). In the dark or under light, all glycerolipids were labelledwhen purified plastids were incubated with [l-14C]-acetate.Light stimulated the incorporation of the label in palmitoyl-MGDG,PG and sulfoquinovosyldiacylglycerol (SL) and also the transferof oleate from PC to MGDG. Only under light and when extraplastidialmembranes were added to isolated plastids, linoleoyl-MGDG, PGand PC were slightly labelled. These results argue for a stimulating effect of light on glycerolipidsynthesis in wheat leaf chloroplasts, on the transfer of oleatefrom PC to MGDG and on the desaturase activity. (Received March 8, 1986; Accepted September 26, 1986) 相似文献
204.
Jean Emberlin Siegfried Jaeger Eugenio Dominguez-Vilches Carmen Galan Soldevilla Lene Hodal Paolo Mandrioli Auli Rantio Lehtimäki Mike Savage Frits Th. Spieksma Catherine Bartlett 《Aerobiologia》2000,16(3-4):373-379
Geographical and temporal variations in the start dates of grass pollen seasons are described for selected sites of the European
Pollen Information Service. Daily average grass pollen counts are derived from Network sites in Finland, the Netherlands,
Denmark, United Kingdom, Austria, Italy and Spain, giving a broad longitudinal transect over Western Europe. The study is
part of a larger project that also examines annual and regional variations in the severity, timing of the peak and duration
of the grass pollen seasons. For several sites, data are available for over twenty years enabling long term trends to be discerned.
The analyses show notable contrasts in the progression of the seasons annually with differing lag times occurring between
southern and northern sites in various years depending on the weather conditions. The patterns identified provide some insight
into geographical differences and temporal trends in the incidence of pollinosis. The paper discusses the main difficulties
involved in this type of analysis and notes possibilities for using data from the European Pollen Information service to construct
pan European predictive models for pollen seasons.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
205.
Nutrient cycling through phytoplankton, bacteria and protozoa, in selectively filtered Lake Vechten water 总被引:2,自引:0,他引:2
Bloem Jaap; Albert Claudia; Bar-Gillissen Marie-Jose B.; Berman Thomas; Cappenberg Thomas E. 《Journal of plankton research》1989,11(1):119-131
The breakdown of organic carbon of dead Synechococcus cell walls,added to selectively filtered Lake Vechten water, was not acceleratedby protozoa. During 4 weeks of incubation at 15°C no significantdecrease of total organic carbon was observed. However, heterotrophicnanoflagel-lates (HNAN) and ciliates strongly increased theremineralization of N and especially P, from both cell wallsand cell extract. Bacterioplankton growth did not result innet P mineralization but in P uptake. P was remineralized onlyin the presence of protozoan grazers. Both HNAN and ciliatesgrazed on bacteria, with ingestion rates estimated at 2796bad HNAN1 h1 and 129 bact ciliate1 h1respectively. Grazers increased N mineralization too, althoughN was also mineralized in the absence of protozoa. The phytoplanktoncell walls yielded less P but more N remineralization than thecell extract. Thus, protozoa can strongly accelerate cyclingof specific nutrients through plankton. Nuclepore filters werefound to cause artificial DOC release during selective filtration. 相似文献
206.
K. Arévalo-Niño C. F. Sandoval L. J. Galan S. H. Imam S. H. Gordon R. V. Greene 《Biodegradation》1996,7(3):231-237
Plastic formulations containing up to 40% starch were prepared and blown into thin films using extrusion methods. Extruded films were evaluated for their biodegradability by exposing them to a consortium of starch degrading bacteria in the laboratory for 45 days and in the ‘La Silla’ river located in Monterrey, N.L. Mexico for up to 60 days. Biodegradability was assessed by measuring changes in weight loss and chemical composition of the films using Fourier transform infrared (FTIR) spectroscopy. While little or no degradation was apparent in control films made up of 100% low density polyethylene (LDPE) or 100% poly-(ethylene-co-acrylic acid) (EAA), most of the starch was depleted in starch-containing films exposed in the river. Starch degradation in films exposed to amylolytic bacteria in the laboratory was relatively slower. Also, increasing the amount of EAA from 25% to 50% substantially reduced starch depletion in these films. 相似文献
207.
E. Redeker J. M. N. Hoovers M. Alders C. J. A. van Moorsel A. C. Ivens S. Gregory L. Kalikin J. Bliek L. de Galan R. van den Bogaard J. Visser R. van der Voort A. P. Feinberg P. F. R. Little A. Westerveld M. Mannens 《Genomics》1994,21(3)
Using a panel of patient cell lines with chromosomal breakpoints, we constructed a physical map for the short arm of human chromosome 11. We focused on 11p15, a chromosome band harboring at least 25 known genes and associated with the Beckwith-Wiedemann syndrome, several childhood tumors, and genomic imprinting. This underlines the need for a physical map for this region. We divided the short arm of chromosome 11 into 18 breakpoint regions, and a large series of new and previously described genes and markers was mapped within these intervals using fluorescence in situ hybridization. Cosmid fingerprint analysis showed that 19 of these markers were included in cosmid contigs. A detailed 10-Mb pulsed-field physical map of the region 11p15.3-pter was constructed. These three different approaches enabled the high-resolution mapping of 210 markers, including 22 known genes. 相似文献
208.