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  • 1
    Publication Date: 2018-12-17
    Description: Recent global warming is pronounced in high-latitude regions (e.g. northern Asia), and will cause the vegetation to change. Future vegetation trends (e.g. the “arctic greening”) will feed back into atmospheric circulation and the global climate system. Understanding the nature and causes of past vegetation changes is important for predicting the composition and distribution of future vegetation communities. Fossil pollen records from 468 sites in northern and eastern Asia were biomised at selected times between 40 cal ka bp and today. Biomes were also simulated using a climate-driven biome model and results from the two approaches compared in order to help understand the mechanisms behind the observed vegetation changes. The consistent biome results inferred by both approaches reveal that long-term and broad-scale vegetation patterns reflect global- to hemispheric-scale climate changes. Forest biomes increase around the beginning of the late deglaciation, become more widespread during the early and middle Holocene, and decrease in the late Holocene in fringe areas of the Asian Summer Monsoon. At the southern and southwestern margins of the taiga, forest increases in the early Holocene and shows notable species succession, which may have been caused by winter warming at ca. 7 cal ka bp. At the northeastern taiga margin (central Yakutia and northeastern Siberia), shrub expansion during the last deglaciation appears to prevent the permafrost from thawing and hinders the northward expansion of evergreen needle-leaved species until ca. 7 cal ka bp. The vegetation-climate disequilibrium during the early Holocene in the taiga-tundra transition zone suggests that projected climate warming will not cause a northward expansion of evergreen needle-leaved species.
    Type: Article , PeerReviewed
    Format: text
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  • 2
    Publication Date: 2015-01-19
    Description: The mechanisms that drive microbial turnover in time and space have received considerable attention but remain unclear, especially for situations with anthropogenic perturbation. To understand the impact of long-term oil contamination on microbial spatial turnover, 100 soil samples were taken from five oil exploration fields located in different geographic regions across China. The microbial functional diversity was analyzed with a high-throughput functional gene array, GeoChip. Our results indicated that soil microbial α-diversity (richness and Shannon diversity index) decreased significantly with contamination. All contaminated and uncontaminated samples exhibited significant spatial autocorrelation between microbial community similarity and spatial distance, as described by a distance decay relationship (DDR). However, long-term oil exposure flattened the slopes of the DDRs of all of the functional genes and each functional group involved in C/N/P/S cycling, particularly of those involved in contaminant degradation. The relative importance of deterministic and stochastic processes in microbial assembly was determined. The decrease in microbial spatial turnover with long-term oil contamination was coupled with an increase in the proportion of deterministic processes that structured microbial assembly based on null model analysis. The results indicated long-term oil contamination significantly affects soil microbial community spatial structure by acting as an environmental filter to decrease the regional differences distinguishing soil microbial communities. # doi:10.1890/14-1672.1
    Print ISSN: 1051-0761
    Electronic ISSN: 1939-5582
    Topics: Biology
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  • 3
    Publication Date: 2015-08-08
    Description: SarV, a member of the SarA protein family, is a global transcriptional regulator which has been reported to be involved in the regulation of autolysis in Staphylococcus aureus . In this study, SarV from S. aureus was successfully cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 2.10 Å resolution. The crystals of SarV belonged to the monoclinic space group P 2 1 , with unit-cell parameters a = 36.40, b = 119.64, c = 66.80 Å, α = γ = 90, β = 98.75°. The Matthews coefficient and the solvent content were estimated to be 2.57 Å 3  Da −1 and 52%, respectively, suggesting the presence of four molecules in the asymmetric unit. The results of size-exclusion chromatography (SEC) indicated that S. aureus SarV exists as a homodimer in solution. Unfortunately, the structure cannot be solved by molecular replacement because of the low sequence identity of S. aureus SarV to known structures. Further phase determination by selenomethionine single-wavelength anomalous dispersion (SAD) and the heavy-atom method is in progress.
    Electronic ISSN: 1744-3091
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Physics
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  • 4
    Publication Date: 2015-10-31
    Description: ABSTRACT We report an ingenious method of super-resolution optical microscopy utilizing scannable cantilever-combined microsphere. By scanning the microsphere over the sample surface in a cantilever-combined microsphere-sample contact state, super-resolution images can be acquired at arbitrary sample regions through near-field information collection by the microsphere. In addition, such a state can effectively reduce the possibility of breaking the cantilever and damaging the microsphere or sample surface. This work has developed a new method and technique of sub-diffraction-limit optical microscopy, and can be practically applied in various fields of micro/nanoscopy. Microsc. Res. Tech., 2015 . © 2015 Wiley Periodicals, Inc.
    Print ISSN: 1059-910X
    Electronic ISSN: 1097-0029
    Topics: Natural Sciences in General
    Published by Wiley-Blackwell
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  • 5
    Publication Date: 2016-05-22
    Description: Global warming during the Paleocene-Eocene Thermal Maximum (PETM) ∼55.5 million years ago (Ma) was associated with a massive release of carbon to the ocean-atmosphere system, as evidenced by a prominent negative carbon isotope excursion (CIE) and widespread dissolution of marine carbonates. The paleohydrologic response to the PETM warming has been studied worldwide; however, relevant records of environmental perturbation in Asia are lacking so far. Here we extend the record of this event in central China, a subtropical paleosetting, through geochemical and mineralogical analyses of lacustrine sediments. Geochemical indicators of authigenic carbonates – including molar Mg/Ca and Sr/Ca ratios – suggest an overall increased precipitation across the PETM, compatible with the disappearance of authigenic dolomite and the appearance of kaolinite in the strata. The relatively humid conditions persisted long after the carbon-cycle perturbation had stopped, implying that the transient hyper-greenhouse warming might have forced the regional climate system into a new climate state that was not easily reversed. Additionally, a gradual increase in chemical index of alteration (CIA) and the appearance of kaolinite are associated with the PETM, indicating an intensified silicate weathering and pedogenesis in the watershed in response to warmer and more humid climate. Our results corroborate the theory that an accelerated continental chemical weathering served as a negative feedback to sequester carbon and lower the atmospheric greenhouse-gas levels during the PETM. This article is protected by copyright. All rights reserved.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
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  • 6
    Publication Date: 2016-05-27
    Description: Autophagy is not only involved in development, but also has been proved to attend immune response against invading pathogens. Autophagy protein 5 (ATG5) is an important autophagic protein, which plays a crucial role in autophagosome elongation. Although ATG5 has been well studied in mammal, yeast, and Drosophila , little is known about ATG5 in lepidopteran insects. We cloned putative SeAtg5 gene from Spodoptera exigua larvae by the rapid amplification of cDNA ends method, and its characteristics and the influences of multiple exogenous factors on its expression levels were then investigated. The results showed that the putative S. exigua SeATG5 protein is highly homologous to other insect ATG5 proteins, which has a conserved Pfm domain and multiple phosphorylation sites. Next, fluorescence microscope observation showed that mCherry-SeATG5 was distributed in both nucleus and cytoplasm of Spodoptera litura Sl-HP cells and partially co-localized with BmATG6-GFP, but it almost has no significant co-localization with GFP-HaATG8. Then, the Western blot analysis demonstrated that GFP-SeATG5 conjugated with ATG12. Moreover, real-time PCR revealed that its expression levels significantly increased at the initiation of pupation and the stage of adult. In addition, the expression levels of SeAtg5 can be enhanced by the starvation, UV radiation, and infection of baculovirus and bacterium. However, the expression levels of SeAtg5 decreased at 24 h post treatments in all these treatments except in starvation. These results suggested that SeATG5 might be involved in response of S. exigua under various stress conditions.
    Print ISSN: 0739-4462
    Electronic ISSN: 1520-6327
    Topics: Biology
    Published by Wiley-Blackwell
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  • 7
    Publication Date: 2017-06-04
    Description: Purpose To assess the efficacy of diffusion kurtosis imaging (DKI) and to compare DKI-derived parameters with that of conventional diffusion-weighted imaging (DWI) for grading the inflammatory activity of Crohn's disease (CD). Materials and Methods In all, 38 patients with CD underwent 3T magnetic resonance enterography (MRE) with DKI (b values of 0–2000 s/mm 2 ). The inflammatory activity of the bowel segments was graded by magnetic resonance index of activity (MaRIA) as inactive (〈7), mild (≥7 and 〈11), or moderate-severe (≥11). Apparent diffusion for non-Gaussian distribution (D app ) and apparent kurtosis coefficient (K app ) on DKI as well as apparent diffusion coefficient (ADC) on DWI were compared. Results In all, 86 bowel segments including inactive (20), mild (19), and moderate-severe (47) CD were analyzed. The differences in K app , D app , and ADC among inactive, mild, and moderate-severe CD were significant (all P 〈 0.05). K app ( r = 0.862), D app ( r = −0.755), and ADC ( r = −0.713) correlated well with MaRIA in all segments. Stronger correlation with MaRIA in moderate-severe CD was found for K app ( r = 0.647) than that of D app ( r = −0.414) and ADC ( r = −0.580). Receiver operating characteristic (ROC) curve analysis showed high accuracy of K app , D app , and ADC for differentiating active from inactive CD (AUC: 0.953 for K app , 0.944 for D app , 0.907 for ADC) as well as differentiating inactive-mild from moderate-severe CD (AUC: 0.946 for K app , 0.887 for D app , 0.846 for ADC). The threshold K app of 0.731 allowed differentiation of active from inactive CD with 89.4% sensitivity and 95% specificity. Conclusion DKI of CD is clinically feasible and might be superior to conventional DWI for grading the inflammatory activity of CD. Level of Evidence : 2 Technical Efficacy : Stage 2 J. Magn. Reson. Imaging 2017.
    Print ISSN: 1053-1807
    Electronic ISSN: 1522-2586
    Topics: Medicine
    Published by Wiley-Blackwell
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  • 8
    Publication Date: 2017-10-03
    Description: Brain-derived neurotrophic factor (BDNF) is a neurotrophin that can promote the development and proliferation of neurons. BDNF has been found to be involved in male reproduction. Leydig cells in testicular interstitial tissues can secrete testosterone in a luteinizing hormone-dependent manner. We showed that BDNF and its receptor TrkB were expressed in mice TM3 Leydig cells in the present study. Furthermore, BDNF can promote proliferation of mouse TM3 Leydig cells in vitro. Results of microRNA (miRNA) deep sequencing showed that BDNF can alter the expression profile of miRNAs in TM3 Leydig cells. Eighty-three miRNAs were significantly different in the BDNF-treated and control groups (fold change of 〉2.0 or 〈0.5, P  〈 0.05) wherein 40 were upregulated and 43 were downregulated. The expression levels of miR-125a-5p, miR-22-5p, miR-342-59, miR-451a, miR-148a-5p, miR-29b-3p, miR-199b-5p, and miR-145a-5p were further confirmed by quantitative real-time polymerase chain reaction. Bioinformatic analysis revealed that miRNAs regulated a large number of genes with different functions. Pathway analysis indicated that miRNAs participate in the pathways involved in signal transduction, cancer, metabolism, endocrine system, immune system, and nerve system. This study indicated that miRNAs might be involved in the BDNF-regulated cellular functions of Leydig cells.
    Print ISSN: 0263-6484
    Electronic ISSN: 1099-0844
    Topics: Biology , Medicine
    Published by Wiley-Blackwell
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  • 9
    Publication Date: 2017-11-29
    Description: Although tobacco smoking has been reported as a risk factor for liver cancer, few studies have specifically explored the association among Chinese females and the potential interaction between smoking and other risk factors. A population-based case-control study was conducted and 2,011 liver cancer cases and 7,933 healthy controls were enrolled in Jiangsu, China from 2003 to 2010. Epidemiological data were collected, and serum HBsAg and anti-HCV antibody were measured. Unconditional logistic regression was used to examine association and potential interaction, while semi-Bayes method was employed to make estimates more conservative. The prevalence of serum HBsAg positivity was 43.2% among cases and 6.5% among controls. The adjusted odds ratio for ever smoking was 1.62 (95% CI: 1.33 - 1.96) among male and was 0.82 (95% CI: 0.53-1.26) among female. Age at first cigarette, duration of smoking and pack-years of smoking were all significantly associated with liver cancer among men. Compared to HBsAg negative never-smokers, the adjusted OR was 1.25 (95% CI: 1.03-1.52) for HBsAg-negative ever smokers, was 7.66 (95% CI: 6.05-9.71) for HBsAg-positive never smokers, and was 15.68 (95% CI: 12.06-20.39) for HBsAg-positive ever smokers. These different odds indicated super-additive (RERI: 7.77, 95% CI: 3.81-11.73) and super-multiplicative interactions (ROR: 1.64, 95% CI: 1.17-2.30) between HBV infection and tobacco smoking. Most associations and interactions detected remained statistically significant after semi-Bayes adjustments. Tobacco smoking and HBV infection positively interact in the development of liver cancer. This article is protected by copyright. All rights reserved.
    Print ISSN: 0020-7136
    Electronic ISSN: 1097-0215
    Topics: Biology , Medicine
    Published by Wiley-Blackwell
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  • 10
    Publication Date: 2017-08-17
    Description: Urothelial carcinoma associated 1α (UCA1α) is a novel long non-coding RNA (lncRNA) that regulates bladder cancer proliferation, migration, and invasion. The target genes of UCA1α have, however, not been identified. To address this, a pCDNA3.1(+)-UCA1α over-expression vector was transfected into UM-UC-2 bladder cancer cells. Genes differentially expressed between pCDNA3.1(+)-UCA1α and pCDNA3.1(+) transfected cell were then detected by microarray and bioinformatics analysis. A total of seventy-one differentially expressed genes were identified, including fifty-two up-regulated genes and nineteen down-regulated genes. As expected, the lncRNA UCA1α expression level was significantly increased when compared to that of pCDNA3.1(+) transfected cells. The five most significantly up-regulated and five most significantly down-regulated genes were selected, and their expression levels were also assessed by real time quantitative polymerase chain reaction and western blot. The mRNA and protein expression levels of FOXI3 and GSTA3 were found to be significantly increased, and those of MED18 and TEX101 were found to be significantly decreased. Gene ontology (GO) clustering identified several significant biological processes, cellular components, and molecular functions, associated with lncRNA UCA1α over-expression. The differentially expressed genes were involved in several significant pathways as shown by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway clustering. Cell proliferation activity was significantly increased following overexpression of lncRNA UCA1α increasing over culture time. The present study identifies, for the first time, potential target genes for lncRNA UCA1α in bladder cancer, and provides a significant reference for studying the role of lncRNA UCA1α in bladder cancer. This article is protected by copyright. All rights reserved
    Electronic ISSN: 0091-7419
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Published by Wiley-Blackwell
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