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  • 1
    Publication Date: 2015-10-29
    Description: Lake Taihu has undergone severe eutrophication in the past three decades, and harmful cyanobacteria blooms occur nearly every year in Meiliang Bay at the north end of the lake. To elucidate the potential relationship between seasonal nutrient limitation and phytoplankton proliferation, a 20-year (1991-2012) time series of nutrient limitation in Meiliang Bay was analyzed for deviations between trophic state index (TSI) parameters. Results showed that patterns of nutrient limitation in Meiliang Bay were distinctly seasonal, where phytoplankton growth was generally phosphorus (P)-limited in winter and spring, but nitrogen (N)-limited mainly occurred in summer and fall. This general pattern, however, shifted into N limitation across the four seasons during the mid-1990s because a rapid increase in industrialization led to a significant rise in the input of N and P from inflowing tributaries. The initial patterns were restored by environmental regulation in the end of 1990s, including the Zero Actions plan. Using routine monitoring data, a generalised additive model (GAM) with time and deviations between trophic state indexes for nitrogen and phosphorus (TSIN-TSIP) as explanatory variables was used to explore which nutrient was responsible for limitation of phytoplankton chlorophyll-a (Chl-a) in different seasons. Surprisingly, the model revealed a weak N limitation (TSIN-TSIP = -10) corresponded to peak values of Chl-a in summer-autumn season, which is probably because the phytoplankton community is co-limited by N & P during the period. The shift of nutrition limitation during winter-spring would partially explain high values of Chl-a throughout 1996. This study suggests that seasonal patterns of nutrient limitation must be considered to develop effective management measures to control cyanobacterial blooms.
    Print ISSN: 1129-5767
    Electronic ISSN: 1723-8633
    Topics: Biology
    Published by PAGEPress
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  • 2
    Publication Date: 2015-09-24
    Description: The initiation of innate immunology system could play an important role in the aspect of protection for sperms long-term storage when the sperms got into oviduct of turtles and come into contact with epithelium. The exploration of TLR2/4 distribution and expression in oviduct during hibernation could help make the storage mechanism understandable. The objective of this study was to examine the gene and protein expression profiles in Chinese soft-shelled turtle during hibernation from November to April in the next year. The protein distribution of TLR2/4 was investigated in the magnum, isthmus, uterus, and vagina of the turtle oviduct using immunohistochemistry, and the gene expression of TLR2/4 was analyzed using quantitative real-time PCR (qRT-PCR). The results showed positive TLR2 protein expression primarily in the epithelium of the oviduct. TLR4 immunoreactivity was widely observed in almost every part of the oviduct, particularly in the epithelium and secretory gland membrane. Analysis of protein, mRNA expression revealed the decreased expression of TLR2/4 in the magnum compared with the isthmus, uterus, and vagina during hibernation. The protein and mRNA expression of TLR2 in the magnum, isthmus, uterus, and vagina was decreased in April compared with that in November. TLR4 protein and mRNA expression in the magnum, isthmus, uterus and vagina was decreased in November compared with that in April. These results indicated that TLR2/4 expression might protect the sperm from microbial infections. In contrast to the function of TLR2, which protects sperm during the early stages of hibernation, TLR4 might play a role in later stages of storage. The present study is the first to report the functions of TLR2/4 in reptiles. Positive TLR2 protein expressed primarily in the epithelium of the oviduct. TLR4 immunoreactivity had widely spread in the oviduct, particularly in the epithelium and secretory gland membrane. In contrast to the function of TLR2, which protects sperm during the early stages of hibernation, TLR4 might play a role in later stages of storage.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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  • 3
    Publication Date: 2016-12-15
    Description: Grassland ecosystems act as a crucial role in the global carbon cycle and provide vital ecosystem services for many species. However, these low-productivity and water-limited ecosystems are sensitive and vulnerable to climate perturbations and human intervention, the latter which is often not considered due to lack of spatial information regarding the grassland management. Here by the application of a model tree ensemble (MTE-GRASS) trained on local eddy covariance data and using as predictors gridded climate and management intensity field (grazing and cutting), we first provide an estimate of global grassland gross primary production (GPP). GPP from our study compares well (modelling efficiency NSE=0.85 spatial; NSE between 0.69 and 0.94 interannual) with that from flux measurement. Global grassland GPP was on average 11±0.31 Pg C yr −1 and exhibited significantly increasing trend at both annual and seasonal scale, with an annual increase of 0.023 Pg C (0.2%) from 1982 to 2011. Meanwhile, we found that at both annual and seasonal scale, the trend (except for northern summer) and interannual variability of the GPP are primarily driven by arid/semiarid ecosystems, the latter of which is due to the larger variation in precipitation. Grasslands in arid/semiarid regions have a stronger (33 g C m −2 yr −1 /100 mm) and faster (0-1 month time lag) respond to precipitation than that in other regions. Although globally spatial gradients (71%) and interannual changes (51%) in GPP were mainly driven by precipitation, where most regions with arid/semiarid climate zone, temperature and radiation together shared half of GPP variability which is mainly distributed in the high latitude or cold regions. Our findings and the results of other studies, suggest the overwhelming importance of arid/semiarid regions as a control on grassland ecosystems carbon cycle. Similarly, under the projected future climate change, grassland ecosystems in these regions will be potentially greatly influenced. This article is protected by copyright. All rights reserved.
    Print ISSN: 1354-1013
    Electronic ISSN: 1365-2486
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Published by Wiley-Blackwell
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  • 4
    Publication Date: 2018-01-30
    Description: The mechanism of transition from chronic pressure overload-induced cardiac hypertrophy to heart failure is still unclear. Angiotensin II (Ang II) may be an important factor that mediates the transition in the end-stage of cardiac hypertrophy. In the present study, Goldblatt two-kidney one-clip (2K1C) rat model was used to simulate Ang II-induced hypertension. The elevated Ang II not only induced the concentric hypertrophy of left ventricle and cardiac fibrosis, but also increased the expression and glycosylation of CD147 in 2K1C rats. The left ventricular structure and function detected by echocardiogram showed a sign of the transition from cardiac hypertrophy to heart failure in 16 weeks of 2K1C rats. Ang II can activate N-acetylglucosamine transferase V (GnT-V), a key enzyme for CD147 glycosylation. Retinoic acid, an agonist of GnT-V, further increased glycosylated CD147 and activated matrix metalloproteinase-2/-9 (MMP-2 and MMP-9) in the hypertrophied left ventricle of 2K1C rat. Meanwhile, collagen cross-linking in the hypertrophied left ventricle significantly reduced in 2K1C rats. On the contrary, tunicamycin, an inhibitor of N-glycan biosynthesis, inhibited glycosylation of CD147 and activity of MMP-2 and MMP-9, and then maintained a stable of collagen cross-linking in the 2K1C rat hearts. The above results suggested that Ang II increased glycosylated CD147 which activated MMP-2 and MMP-9. Collagens were degraded by the activated MMPs and then reduced collagen cross-linking. Finally, the hypertrophied left ventricle was progressively dilated in chronic pressure overload due to losing the limitation of collagen cross-linking. Therefore, the compensated hypertrophy of left ventricle gradually transited to congestive heart failure. 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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  • 5
    Publication Date: 2017-12-27
    Description: Placental trophoblast invasion is crucial for embryo implantation and successful pregnancy. Urokinase-type plasminogen activator (uPA)/urokinase-type plasminogen activator receptor (uPAR) are expressed on trophoblasts and involved in trophoblast invasion. The transcription factor activator protein 1 (AP-1) (c-FOS and c-JUN) and fucosyltransferase IV (FUT4) have been found to be involved in trophoblast invasion. However, the relationship of uPA/uPAR, AP1 and FUT4 is unclear in trophoblast invasion. The current study aimed to investigate the role of AP1 in uPA/uPAR-induced FUT4 expression and trophoblast invasion. In this study, we found that p-c-FOS and p-c-JUN were decreased in abortion patients compared to that in normal pregnant women. Employing human trophoblastic cell lines, we then demonstrated that uPA/uPAR induced the expression of p-c-FOS and p-c-JUN. Applying an electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP), we further proved that AP1 is the specific trans factor for the FUT4 promoter that could transcriptionally increase FUT4 transcriptional activity, further promoting trophoblast cell migration and invasion. Taken together, these results suggest that uPA/uPAR induces FUT4 expression and trophoblast cell invasion mediated by the AP-1 transcription factors c-FOS and c-JUN. Our findings provide novel insights into the mechanisms of the early events of pregnancy. 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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  • 6
    Publication Date: 2018-03-14
    Description: In the southwestern Okinawa Trough, a cluster of approximate 70 submarine volcanoes is located at the cross back-arc volcanic trail (CBVT), with the eruptive products dominated by rhyolites. New whole-rock major and trace element and Sr–Nd–Pb–O isotopic data and previously available geochemistry data of volcanic rocks from this region are presented to determine the petrogenesis of these rhyolites. The rhyolites have high SiO 2 (〉70.01 wt.%), K 2 O + Na 2 O (6.71–7.16 wt.%) contents and differentiation index (DI) values (DI 〉 93), and are metaluminous to weakly peraluminous (A/CNK = 0.99–1.11) and medium-K calc-alkaline in composition. The relatively low 10 4 *Ga/Al (2.06–2.17) and FeO*/MgO ratios (4.50–6.62), as well as Zr (91–174 ppm) and Zr + Ce + Nb + Y (175–271) contents suggest that the rhyolites, which contain hornblende, are generally similar to those of typical highly fractionated I-type granitoids. The rhyolites show arc-related features such as enrichment in LILEs (Rb, Ba, K), Th, U, Pb, and LREEs ((La/Yb) N  = 6.21–6.74) and strong depletion in HFSEs (Nb, Ta, P, Ti) with both nearly identical and more enriched isotopic compositions, including εNd (from −3.2 to −3.5), 87 Sr/ 86 Sr ratios (0.705552 to 0.705713), δ 18 O values (+8.1‰ to +8.6‰), and Pb isotopic compositions ( 206 Pb/ 204 Pb = 18.568–18.589, 207 Pb/ 204 Pb = 15.641–15.656, and 208 Pb/ 204 Pb = 38.848–38.904). Based on these characteristics, we propose that subduction-related basalt magma and crust-derived magma mixed and homogenized within a shallow magma chamber with a homogeneous “base-level” isotopic signature of 〉0·7055 ( 87 Sr/ 86 Sr) and 〉 −3 (εNd). This magma would have then experienced the extensive fractional crystallization of minerals, including plagioclase, hornblende, apatite, sphene, and Fe–Ti oxides, to form the CBVT rhyolites. Our geochemical interpretation of the existence of a long-lived, convecting magma chamber beneath the CBVT is also consistent with seismic tomography results.
    Print ISSN: 0072-1050
    Electronic ISSN: 1099-1034
    Topics: Geosciences
    Published by Wiley-Blackwell
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  • 7
    Publication Date: 2018-02-14
    Description: Background The present of metastases is a poor prognostic factor in prostate cancer, but the prognostic impact of different distant metastases pattern is unclear. The aim of this study is to investigate the impact of different distant metastases pattern on the survival of patients with stage IV prostate cancer. Methods Data queried for this study include prostate cancer (2010-2014) from the Surveillance, Epidemiology, and End Results (SEER) program. Metastatic distribution information was provided for bone, brain, liver and lung. The overall survival was calculated by the Kaplan-Meier method. Multivariable Cox regression models were used to analyze survival outcome and risk factors. Results A total of 265 900 eligible patients were identified from SEER database. Among these patients, stage of IV prostate cancer accounted for 7.53% (20 034/265 900) at diagnosis. Patients who suffered metastasis to either one of the four organs occupied 61.24% (12 268/20 034) in stage of IV patients. Comparing with other three single metastases, the patients with liver metastasis exhibited worst OS whose mean survival was 17.529 months ( P  〈 0.001). The mean survival of metastases with bong and lung was 25.238 months, which was the best survival of the six forms with two metastatic sites ( P  〈 0.001). The results of univariate survival analysis showed that metastatic forms, race, N-classification and differentiated grade did not have impact on the overall survival of patients with three metastatic sites (all, P  〉 0.05). Conclusions In analysis of both one and two metastatic sites, patients with liver metastasis seemed to have worse survival outcome. On the other hand, bone metastasis had better outcome than other three visceral metastases. Knowledge of these differences in metastatic patterns may help to better guide pre-treatment evaluation of prostate cancer and make determination regarding curative-intent interventions.
    Print ISSN: 0270-4137
    Electronic ISSN: 1097-0045
    Topics: Medicine
    Published by Wiley-Blackwell
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  • 8
    Publication Date: 2017-06-15
    Description: Wood density (WD) is not only an important parameter to estimate aboveground biomass but also an indicator of timber quality and plant adaptation strategies to stressful conditions (i.e., windthrow, pests, and pathogens). This study had three objectives: (1) to compare WD among seven subtropical tree species; (2) to determine how tree growth traits may influence possible differences in WD between the pioneer and shade-tolerant species; and (3) to examine whether or not WD differs by tree social status (dominant vs. suppressed trees) within species. To do this, 70 trees were destructively harvested. From each tree, disks at different stem heights were obtained and subjected to a method of stem analysis to measure whole tree level WD. The results showed that WD differed significantly among the seven species ( p  〈 .001). Their average WD was 0.537 g/cm 3 , ranging from 0.409 g/cm 3 for Choerospondias axillaris to 0.691 g/cm 3 for Cyclobalanopsis glauca . The average WD of the four pioneer species (0.497 ± 0.13 g/cm 3 ) was significantly lower ( p  〈 .01) than that of the three shade-tolerant species (0.589 ± 0.12 g/cm 3 ). The WD of the pioneers had a significant positive correlation with their stem diameter at breast height (DBH), tree height ( H ), and tree age, but WD had a significant negative correlation with relative growth rate (RGR). In contrast, the WD of the shade-tolerant tree species had no significant relationships with DBH, H , tree age, or RGR. The dominant trees of the pioneer species had a higher WD than the suppressed trees, whereas the shade-tolerant species had a lower WD for dominant trees than the suppressed trees. However, the differences in WD between dominant and suppressed trees were not significant. Taken together, the results suggest that classifying species into pioneer and shade-tolerant groups to examine the effects of tree growth traits and social status could improve our understanding of intra- and interspecific variation in WD among subtropical tree species. We investigated inter- and intraspecific variation in WD among seven tree species in the subtropical region of Jingzhou County, Hunan Province, southern China. And the results imply that influences of tree growth traits and social status on WD were more pronounced for early successional tree species than late successional tree species in subtropical China
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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