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131.
The effect of vascular plants on carbon turnover and methane emissions from a tundra wetland 总被引:7,自引:0,他引:7
Lena Ström Anna Ekberg Mikhail Mastepanov Torben Røjle Christensen 《Global Change Biology》2003,9(8):1185-1192
This paper investigates how vascular plants affect carbon flow and the formation and emission of the greenhouse gas methane (CH4) in an arctic wet tundra ecosystem in NE Greenland. We present a field experiment where we studied, in particular, how species‐specific root exudation patterns affect the availability of acetate, a hypothesized precursor of CH4 formation. We found significantly higher acetate formation rates in the root vicinity of Eriophorum scheuchzeri compared with another dominating sedge in the wetland, i.e. Dupontia psilosantha. Furthermore a shading treatment, which reduced net photosynthesis, resulted in significantly decreased formation rates of acetate. We also found that the potential CH4 production of the peat profile was highly positively correlated to the concentration of acetate at the respective depths, whereas it was negatively correlated to the concentration of total dissolved organic carbon. This suggests that acetate is a substrate of importance to the methanogens in the studied ecosystem and that acetate concentration in this case can serve as a predictor of substrate quality. To further investigate the importance of acetate as a predecessor to CH4, we brought an intact peat‐plant monolith system collected at the field site in NE Greenland to the laboratory, sealed it hermetically and studied the decomposition of 14C‐labelled acetate injected at the depth of methanogenic activity. After 4 h, 14CH4 emission from the monolith could be observed. In conclusion, allocation of recently fixed carbon to the roots of certain species of vascular plants affects substrate quality and influence CH4 formation. 相似文献
132.
Christine Finnie Merethe Bagge Torben Steenholdt Ole Østergaard Kristian Sass Bak-Jensen Gunter Backes Anaïs Jensen Henriette Giese Jørgen Larsen Peter Roepstorff Birte Svensson 《Functional & integrative genomics》2009,9(1):135-143
Two-dimensional gel electrophoresis was used to screen spring barley cultivars for differences in seed protein profiles. In
parallel, 72 microsatellite (simple sequence repeat (SSR)) markers and 11 malting quality parameters were analysed for each
cultivar. Over 60 protein spots displayed cultivar variation, including peroxidases, serpins and proteins with unknown functions.
Cultivars were clustered based on the spot variation matrix. Cultivars with superior malting quality grouped together, indicating
malting quality to be more closely correlated with seed proteomes than with SSR profiles. Mass spectrometry showed that some
spot variations were caused by amino acid differences encoded by single nucleotide polymorphisms (SNPs). Coding SNPs were
validated by mass spectrometry, expressed sequence tag and 2D gel data. Coding SNPs can alter function of affected proteins
and may thus represent a link between cultivar traits, proteome and genome. Proteome analysis of doubled haploid lines derived
from a cross between a malting (Scarlett) and a feed cultivar (Meltan) enabled genetic localisation of protein phenotypes
represented by 48 spot variations, involving e.g. peroxidases, serpins, α-amylase/trypsin inhibitors, peroxiredoxin and a
small heat shock protein, in relation to markers on the chromosome map.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
133.
Klavs B. Hendil Keiji Tanaka Anne-Marie B. Lauridsen Rasmus Hartmann-Petersen 《Journal of molecular biology》2009,394(2):320-2299
26S proteasomes consist of cylindrical 20S proteasomes with 19S regulatory complexes attached to the ends. Treatment with high concentrations of salt causes the regulatory complexes to separate into two sub-complexes, the base, which is in contact with the 20S proteasome, and the lid, which is the distal part of the 19S complex. Here, we describe two assembly intermediates of the human regulatory complex. One is a dimer of the two ATPase subunits, Rpt3 and Rpt6. The other is a complex of nascent Rpn2, Rpn10, Rpn11, Rpn13, and Txnl1, attached to preexisting 20S proteasomes. This early assembly complex does not yet contain Rpn1 or any of the ATPase subunits of the base. Thus, assembly of 19S regulatory complexes takes place on preexisting 20S proteasomes, and part of the lid is assembled before the base. 相似文献
134.
Camilla Noelle Rathcke Johan Holmkvist Lise Lotte N. Husmoen Torben Hansen Oluf Pedersen Henrik Vestergaard Allan Linneberg 《PloS one》2009,4(7)
Background
YKL-40 is a chitinase-like glycoprotein encoded by the chitinase 3-like 1 gene, CHI3L1, localized at chromosome 1q32.1. Increased levels of serum YKL-40 have been reported to be a biomarker for asthma and a reduced lung function. Interestingly, the C-allele of the -131 C→G (rs4950928) polymorphism of CHI3L1 has been shown to associate with bronchial hyperresponsiveness and reduced lung function suggesting that variations in CHI3L1 may influence risk of asthma. The objective of the present study was to investigate the association of common variation in the CHI3L1 locus with asthma, atopy and lung function in a large population-based sample of adults.Methods/Principal Findings
Eleven single nucleotide polymorphisms (SNPs) of CHI3L1 including rs4950928 were genotyped in 6514 individuals. Asthma was defined as self-reported history of physician-diagnosed asthma. Total IgE and specific IgE to inhalant allergens were measured on serum samples. Lung function was measured by spirometry. Homozygosity of the rs4950928 G allele as compared to homozygosity of the C allele was associated with self-reported physician diagnosed asthma (OR 1.5 (95% CI, 1.00–2.26)) and with prevalence of atopic asthma (OR 1.93 (95% CI, 1.21–3.07)) after adjustment for age, sex, smoking status, socio-economic class and BMI. Carriers of rs883125 G allele had a significantly lower prevalence of atopy (OR 0.82 (CI, 0.72; 0.94)) as compared to homozygosity of the C allele. None of the SNPs examined were significantly associated with FEV1. However, two SNPs (rs10399931and rs4950930) appeared to be significantly associated with FEV1/FVC-ratio. Subgroup analyses of never-smokers did not consistently influence the associations in an either positively og negatively way.Conclusions
In contrast to previous studies, the rs4950928 G allele, and not the C allele, was found to be associated with asthma. A few other SNPs of the CHI3L1 was found to be significantly associated with atopy and FEV1/FVC ratio, respectively. Thus, more studies seem warranted to establish the role of CHI3L1 gene in asthma and atopy. 相似文献135.
136.
The secreted morphogens of the Hedgehog family have important roles in normal development as well as in associated pathologies, including cancer. The Hedgehog signalling pathway has been studied in Drosophila and is thought to be conserved in vertebrates. Hedgehog elicits a signalling response that activates Smoothened (Smo). There is evidence of differences between Drosophila and vertebrates concerning signalling downstream of Smo, as well as in Smo itself. Here, we discuss this evidence and its importance for investigations of the pathway and related biology, as well as for the development of drugs targeting components of the pathway for treatment of associated pathologies. 相似文献
137.
Jørgensen JP Lauridsen AM Kristensen P Dissing K Johnsen AH Hendil KB Hartmann-Petersen R 《Journal of molecular biology》2006,360(5):1043-1052
We have identified Adrm1 as a novel component of the regulatory ATPase complex of the 26 S proteasome: Adrm1 was precipitated with an antibody to proteasomes and vice versa. Adrm1 co-migrated with proteasomes on gel-filtration chromatography and non-denaturing polyacrylamide gel electrophoresis. Adrm1 has been described as an interferon-gamma-inducible, heavily glycosylated membrane protein of 110 kDa. However, we found Adrm1 in mouse tissues only as a 42 kDa peptide, corresponding to the mass of the non-glycosylated peptide chain, and it could not be induced in HeLa cells with interferon. Adrm1 was present almost exclusively in soluble 26 S proteasomes, albeit a small fraction was membrane-associated, like proteasomes. Adrm1 was found in cells in amounts equimolar with S6a, a 26 S proteasome subunit. HeLa cells contain no pool of free Adrm1 but recombinant Adrm1 could bind to pre-existing 26 S proteasomes in cell extracts. Adrm1 may be distantly related to the yeast proteasome subunit Rpn13, mutants of which are reported to display no obvious phenotype. Accordingly, knock-down of Adrm1 in HeLa cells had no effect on the amount of proteasomes, or on degradation of bulk cell protein, or accumulation of polyubiquitinylated proteins. This indicates that Adrm1 has a specialised role in proteasome function. 相似文献
138.
P25alpha/tubulin polymerization promoting protein (TPPP) is a brain specific phosphoprotein that displays microtubule bundling activity. In the mature brain, p25alpha/TPPP distributes to oligodendrocytes and choroid plexus epithelium. We mapped the spatial and temporal distribution of p25alpha/TPPP in the developing rat brain. Having localized its expression to neuronal tissue by Western blot analyses, the distribution of p25alpha/TPPP to developing oligodendrocytes was confirmed using a specific antibody. In the pre-natal and post-natal brain, p25alpha/TPPP was localized to the perinuclear cytoplasm of myelinating oligodendrocytes from embryonic (E) day E20 as verified from cellular co-localization with 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP). Oligodendrocyte progenitor cells and pre-myelinating oligodendrocytes identified by the expression of NG2 proteoglycan and CD9, respectively, both failed to contain p25alpha/TPPP. In contrast, P25alpha/TPPP co-localized with beta(IV)-tubulin from post-natal (p) day P10 suggesting that p25alpha/TPPP plays an important role for tubulin-related transport in developing, myelinating oligodendrocytes. 相似文献
139.
Lise Lotte N. Husemoen Torben J?rgensen Knut Borch-Johnsen Torben Hansen Oluf Pedersen Allan Linneberg 《PloS one》2010,5(8)
Background
Epidemiological studies have shown a J- or U-shaped relation between alcohol and type 2 diabetes and coronary heart disease (CHD). The underlying mechanisms are not clear. The aim was to examine the association between alcohol intake and diabetes and intermediate CHD risk factors in relation to selected ADH and ALDH gene variants.Methodology/Principal Findings
Cross-sectional study including 6,405 Northern European men and women aged 30–60 years from the general population of Copenhagen, Denmark. Data were collected with self-administered questionnaires, a physical examination, a 2 hour oral glucose tolerance test, and various blood tests. J shaped associations were observed between alcohol and diabetes, metabolic syndrome (MS), systolic and diastolic blood pressure, triglyceride, total cholesterol, and total homocysteine. Positive associations were observed with insulin sensitivity and HDL cholesterol, and a negative association with insulin release. Only a few of the selected ADH and ALDH gene variants was observed to have an effect. The ADH1c (rs1693482) fast metabolizing CC genotype was associated with an increased risk of impaired glucose tolerance (IGT)/diabetes compared to the CT and TT genotypes. Significant interactions were observed between alcohol and ADH1b (rs1229984) with respect to LDL and between alcohol and ALDH2 (rs886205) with respect to IGT/diabetes.Conclusions/Significance
The selected ADH and ALDH gene variants had only minor effects, and did not seem to markedly modify the health effects of alcohol drinking. The observed statistical significant associations would not be significant, if corrected for multiple testing. 相似文献140.