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61.
Nitrogen fixation in mixed <Emphasis Type="Italic">Hylocomium splendens</Emphasis> moss communities 总被引:1,自引:1,他引:0
The pleurocarpus feather moss, Hylocomium splendens, is one of two co-dominant moss species in boreal forest ecosystems and one of the most common mosses on earth, yet little
is known regarding its capacity to host cyanobacterial associates and thus contribute total ecosystem N. In these studies,
we evaluated the N-fixation potential of the H. splendens–cyanobacteria association and contrasted the N-fixation activity with that of the putative N-fixing moss–cyanobacteria association
of Pleurozium schreberi. Studies were conducted to: quantify N-fixation in H. splendens and P. schreberi in sites ranging from southern to northern Fennoscandia; assess N and P availability as drivers of N-fixation rates; contrast
season-long N-fixation rates for both mosses; and characterize the cyanobacteria that colonize shoots of H. splendens. Nitrogen-fixation rates were generally low at southern latitudes and higher at northern latitudes (64–69°N) potentially
related to anthropogenic N deposition across this gradient. Nitrogen fixation in H. splendens appeared to be less sensitive to N deposition than P. schreberi. The season-long assessment of N-fixation rates at a mixed feather moss site in northern Sweden showed that H. splendens fixed a substantial quantity of N, but about 50% less total N compared to the contribution from P. schreberi. In total, both species provided 1.6 kg fixed N ha−1 year−1. Interestingly, H. splendens demonstrated somewhat higher N-fixation rates at high fertility sites compared to P. schreberi. Nostoc spp. and Stigonema spp. were the primary cyanobacteria found to colonize H. splendens and P. schreberi. These results suggest that H. splendens with associated Nostoc or Stigonema communities contributes a significant quantity of N to boreal forest ecosystems, but the contribution is subordinate to that
of P. schreberi at northern latitudes. Epiphytic cyanobacteria are likely a key factor determining the co-dominant presence of these two
feather mosses across the boreal biome. 相似文献
62.
Sander A. Peters Erwin Datema Dóra Szinay Marjo J. van Staveren Elio G.W.M. Schijlen Jan C. van Haarst Thamara Hesselink Marleen H.C. Abma-Henkens Yuling Bai Hans de Jong Willem J. Stiekema René M. Klein Lankhorst Roeland C.H.J. van Ham 《The Plant journal : for cell and molecular biology》2009,58(5):857-869
63.
The kinase activity of the thanatophoric dysplasia type II-fibroblast growth factor receptor 3 mutant (TDII-FGFR3) hampers its maturation. As a consequence, the immature receptor activates extracellular regulated kinases (ERKs) from the endoplasmic reticulum (ER), which leads to apoptosis. On the other hand, in stable TDII-FGFR3 cells receptor biosynthesis is restored and ERKs are activated from the cell surface. To identify potential mediators of cell adaptation to the activated receptor we investigated gene products that are differently regulated in TDII and wild-type FGFR3 cells. cDNA representational difference analysis reveals Sprouty4 up regulation in the TDII-FGFR3 cells. Interestingly, Sprouty4 inhibits the TDII-FGFR3-mediated ERKs activation from the ER, but fails to suppress ERKs activation from cell surface. We conclude that cell adaptation to activated FGFR3 include Sprouty4 activity, which silences the premature receptor signaling and suppress apoptosis. 相似文献
64.
Neasham D Gallo V Guarrera S Dunning A Overvad K Tjonneland A Clavel-Chapelon F Linseisen JP Malaveille C Ferrari P Boeing H Benetou V Trichopoulou A Palli D Crosignani P Tumino R Panico S Bueno-De-Mesquita HB Peeters PH van Gib CH Lund E Gonzalez CA Martinez C Dorronsoro M Barricarte A Navarro C Quiros JR Berglund G Jarvholm B Khaw KT Key TJ Bingham S Diaz TM Riboli E Matullo G Vineis P 《DNA Repair》2009,8(1):60-71
We followed-up for mortality and cancer incidence 1088 healthy non-smokers from a population-based study, who were characterized for 22 variants in 16 genes involved in DNA repair pathways. Follow-up was 100% complete. The association between polymorphism and mortality or cancer incidence was analyzed using Cox Proportional Hazard regression models. Ninety-five subjects had died in a median follow-up time of 78 months (inter-quartile range 59-93 months). None of the genotypes was clearly associated with total mortality, except variants for two Double-Strand Break DNA repair genes, XRCC3 18067 C>T (rs#861539) and XRCC2 31479 G>A (rs#3218536). Adjusted hazard ratios were 2.25 (1.32-3.83) for the XRCC3 C/T genotype and 2.04 (1.00-4.13) for the T/T genotype (reference C/C), and 2.12 (1.14-3.97) for the XRCC2 G/A genotype (reference G/G). For total cancer mortality, the adjusted hazard ratios were 3.29 (1.23-7.82) for XRCC3 C/T, 2.84 (0.81-9.90) for XRCC3 T/T and 3.17 (1.21-8.30) for XRCC2 G/A. With combinations of three or more adverse alleles, the adjusted hazard ratio for all cause mortality was 17.29 (95% C.I. 8.13-36.74), and for all incident cancers the HR was 5.28 (95% C.I. 2.17-12.85). Observations from this prospective study suggest that polymorphisms of genes involved in the repair of DNA double-strand breaks significantly influence the risk of cancer and non-cancer disease, and can influence mortality. 相似文献
65.
Elena Gabrielli Eva Pericolini Elio Cenci Federica Ortelli Walter Magliani Tecla Ciociola Francesco Bistoni Stefania Conti Anna Vecchiarelli Luciano Polonelli 《PloS one》2009,4(12)
Background
It has been documented that, independently from the specificity of the native antibody (Ab) for a given antigen (Ag), complementarity determining regions (CDR)-related peptides may display differential antimicrobial, antiviral and antitumor activities.Methodology/Principal Findings
In this study we demonstrate that a synthetic peptide with sequence identical to VHCDR3 of a mouse monoclonal Ab (mAb) specific for difucosyl human blood group A is easily taken up by macrophages with subsequent stimulation of: i) proinflammatory cytokine production; ii) PI3K-Akt pathway and iii) TLR-4 expression. Significantly, VHCDR3 exerts therapeutic effect against systemic candidiasis without possessing direct candidacidal properties.Conclusions/Significance
These results open a new scenario about the possibility that, beyond the half life of immunoglobulins, Ab fragments may effectively influence the antiinfective cellular immune response in a way reminiscent of regulatory peptides of innate immunity. 相似文献66.
Bioremediation of crude oil polluted seawater by a hydrocarbon-degrading bacterial strain immobilized on chitin and chitosan flakes 总被引:6,自引:0,他引:6
Alejandro R. Gentili María A. Cubitto Marcela Ferrero María S. Rodriguz 《International biodeterioration & biodegradation》2006,57(4):222-228
In this laboratory-scale study, we examined the potential of chitin and chitosan flakes obtained from shrimp wastes as carrier material for a hydrocarbon-degrading bacterial strain. Flakes decontamination, immobilization conditions and the survival of the immobilized bacterial strain under different storage temperatures were evaluated. The potential of immobilized hydrocarbon-degrading bacterial strain for crude oil polluted seawater bioremediation was tested in seawater microcosms. In terms of removal percentage of crude oil after 15 days, the microcosms treated with the immobilized inoculants proved to be the most successful. The inoculants formulated with chitin and chitosan as carrier materials improved the survival and the activity of the immobilized strain. It is important to emphasize that the inoculants formulated with chitin showed the best performance during storage and seawater bioremediation. 相似文献
67.
Eva Pericolini Elena Gabrielli Giovanni Bistoni Elio Cenci Stefano Perito Siu-Kei Chow Francesca Riuzzi Rosario Donato Arturo Casadevall Anna Vecchiarelli 《PloS one》2010,5(9)
Previously, we reported that Galactoxylomannan (GalXM) activates the extrinsic and intrinsic apoptotic pathways through an interaction with the glycoreceptors on T cells. In this study we establish the role of the glycoreceptor CD45 in GalXM-induced T cell apoptosis, using CD45+/+ and CD45−/− cell lines, derived from BW5147 murine T cell lymphoma. Our results show that whereas CD45 expression is not required for GalXM association by the cells, it is essential for apoptosis induction. In CD45+/+ cells, CD45 triggering by GalXM reduces the activation of Lck, ZAP70 and Erk1/2. Conversely, in CD45−/− cells, Lck was hyperphosphorylated and did not show any modulation after GalXM stimulation. On the whole, our findings provide evidence that the negative regulation of Lck activation occurs via CD45 engagement. This appears to be related to the capacity of GalXM to antagonize T cell activation and induce T cell death. Overall this mechanism may be responsible for the immune paralysis that follows GalXM administration and could explain the powerful immunosuppression that accompanies cryptococcosis. 相似文献
68.
Mazzola V Latorre V Petito A Gentili N Fazio L Popolizio T Blasi G Arciero G Bondolfi G 《PloS one》2010,5(12):e15268
Individual variability in emotion processing may be associated with genetic variation as well as with psychological predispositions such as dispositional affect styles. Our previous fMRI study demonstrated that amygdala reactivity was independently predicted by affective-cognitive styles (phobic prone or eating disorders prone) and genotype of the serotonin transporter in a discrimination task of fearful facial expressions. Since the insula is associated with the subjective evaluation of bodily states and is involved in human feelings, we explored whether its activity could also vary in function of individual differences. In the present fMRI study, the association between dispositional affects and insula reactivity has been examined in two groups of healthy participants categorized according to affective-cognitive styles (phobic prone or eating disorders prone). Images of the faces of partners and strangers, in both painful and neutral situations, were used as visual stimuli. Interaction analyses indicate significantly different activations in the two groups in reaction to a loved one's pain: the phobic prone group exhibited greater activation in the left posterior insula. These results demonstrate that affective-cognitive style is associated with insula activity in pain empathy processing, suggesting a greater involvement of the insula in feelings for a certain cohort of people. In the mapping of individual differences, these results shed new light on variability in neural networks of emotion. 相似文献
69.
Dora Romaguera Lars ?ngquist Huaidong Du Marianne Uhre Jakobsen Nita G. Forouhi Jytte Halkj?r Edith J. M. Feskens Daphne L. van der A Giovanna Masala Annika Steffen Domenico Palli Nicholas J. Wareham Kim Overvad Anne Tj?nneland Heiner Boeing Elio Riboli Thorkild I. A. S?rensen 《PloS one》2010,5(7)
Background
Given the recognized health effects of visceral fat, the understanding of how diet can modulate changes in the phenotype “waist circumference for a given body mass index (WCBMI)”, a proxy measure of visceral adiposity, is deemed necessary. Hence, the objective of the present study was to assess the association between dietary factors and prospective changes in visceral adiposity as measured by changes in the phenotype WCBMI.Methods and Findings
We analyzed data from 48,631 men and women from 5 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Anthropometric measurements were obtained at baseline and after a median follow-up time of 5.5 years. WCBMI was defined as the residuals of waist circumference regressed on body mass index, and annual change in WCBMI (ΔWCBMI, cm/y) was defined as the difference between residuals at follow-up and baseline, divided by follow-up time. The association between energy, energy density (ED), macronutrients, alcohol, glycemic index (GI), glycemic load (GL), fibre and ΔWCBMI was modelled using centre-specific adjusted linear regression, and random-effects meta-analyses to obtain pooled estimates. Men and women with higher ED and GI diets showed significant increases in their WCBMI, compared to those with lower ED and GI [1 kcal/g greater ED predicted a ΔWCBMI of 0.09 cm (95% CI 0.05 to 0.13) in men and 0.15 cm (95% CI 0.09 to 0.21) in women; 10 units greater GI predicted a ΔWCBMI of 0.07 cm (95% CI 0.03 to 0.12) in men and 0.06 cm (95% CI 0.03 to 0.10) in women]. Among women, lower fibre intake, higher GL, and higher alcohol consumption also predicted a higher ΔWCBMI.Conclusions
Results of this study suggest that a diet with low GI and ED may prevent visceral adiposity, defined as the prospective changes in WCBMI. Additional effects may be obtained among women of low alcohol, low GL, and high fibre intake. 相似文献70.